Systems and methods for syringe plunger engagement with an injector

Abstract

A plunger (326) for use with a syringe includes a plunger body (332) defining a central longitudinal axis (334) and having a proximal end (336), a distal end (338), and a circumferential sidewall (339) connecting the proximal and distal ends. The plunger further includes at least one retention member (368) associated with the plunger body and extending proximally therefrom. The at least one retention member has a first end connected to the plunger body, a second end proximal to and radially resiliently deflectable relative to the first end, and at least one catch (374) on the second end. A fluid injector system includes a piston (400) having a plunger engagement mechanism configured to interact with the at least one retention element of the plunger to releasably engage the plunger for reciprocally driving the plunger within a barrel of the syringe.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 705,265, filed June 18, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to systems including a front-loading syringe and / or pressure sheath for use with a fluid injector, and further relates to a connection interface for securing a syringe plunger to a piston of the fluid injector, and a method for engaging and disengaging the syringe plunger from the piston of the fluid injector. Background Technology

[0004] In many medical diagnostic and treatment procedures, healthcare practitioners administer one or more medical fluids to patients. Various injector-actuated syringes and fluid injectors have been developed for pressurized injection of fluids such as contrast solutions (often simply referred to as "contrast"), irrigants (such as saline or Ringer's lactate), and other medical fluids, for use in contrast-enhanced imaging procedures such as angiography, computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), positron emission tomography (PET), and other imaging processes. Generally, these fluid injectors are designed to deliver a predetermined amount of one or more fluids at a predetermined flow rate.

[0005] Typically, a fluid injector has at least one drive member, such as a piston, connected to a syringe, for example, via an engagement feature on the proximal wall of a plunger or syringe. The syringe may include a rigid barrel in which a syringe plunger is slidably disposed. At least one drive member drives the plunger in a proximal and / or distal direction relative to the longitudinal axis of the barrel to draw fluid into or deliver fluid from the syringe barrel.

[0006] Various connection interfaces have been developed to facilitate engagement between the syringe plunger and the piston of the fluid injector. In some embodiments, the syringe, having a retaining feature, is inserted into the syringe port on the fluid injector by aligning the syringe with a corresponding locking feature disposed on the fluid injector. This alignment also aligns the plunger in the syringe with the piston on the fluid injector, such that the piston can engage the plunger and reciprocate to drive the plunger through the syringe barrel to draw fluid into or deliver fluid from and to the syringe barrel. In other embodiments, upon initial engagement with the plunger, the piston rotates clockwise or counterclockwise until the piston engages with a snap-fit ​​on the plunger. In a further embodiment, the piston has a radially extendable pin that engages a lip on the plunger.

[0007] Many existing connectors require complex piston heads with various sensor elements and active engagement mechanisms. There is a need in the art for improved connectors that allow for simpler and easier engagement and disengagement of the syringe plunger with the fluid injector piston. There is also a need in the art to reduce or eliminate the need for the operator to rotate the syringe to align it with the fluid injector before engaging the syringe plunger with the fluid injector piston. While various syringe connectors and methods are known in the medical field, there remains a need for improved connectors between the syringe plunger and the fluid injector piston, as well as methods for engaging and disengaging the syringe plunger with the fluid injector piston. Summary of the Invention

[0008] There is a need in the art for an improved connection interface between the syringe plunger and the piston of the fluid injector to overcome the shortcomings of the prior art. There is also a need for improved methods for engaging and disengaging the syringe plunger from the piston of the fluid injector to allow for easy loading or removal of the syringe from the fluid injector.

[0009] According to some embodiments, a plunger for use with a syringe may include: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and circumferential sidewalls connecting the proximal and distal ends; and at least one retaining member associated with and extending proximally from the plunger body, the at least one retaining member including: a first end connected to the plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one latch on the second end, wherein the at least one retaining member may have an outer surface configured to engage the plunger on a piston of a fluid injector system when the plunger is in a locked state with a piston. A plunger engagement sleeve of an engagement mechanism, wherein at least one retaining member may have an inner surface configured to engage a plunger engagement post of the plunger engagement mechanism when the plunger is in a locked state with a piston, wherein at least one latch may be configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger is in a locked state with a piston to prevent axial movement of the plunger relative to the piston, and wherein at least one latch may be configured to cause a second end of at least one retaining member to radially deflect when the piston moves axially relative to the plunger in an unlocked state due to engagement of at least one latch with a locking feature on one of the plunger engagement sleeve and the plunger engagement post.

[0010] According to some embodiments, at least one retaining member may include a plurality of retaining members spaced apart around the central longitudinal axis. The plurality of retaining members may be spaced apart at equal intervals around the central longitudinal axis. At least one retaining member may extend proximally in a direction parallel to the central longitudinal axis or in a direction angular to the central longitudinal axis. At least one retaining member may be linearly or curvilinearly abutted between a first end and a second end. The plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector.

[0011] According to some embodiments, at least one snap may have a first surface at the proximal end of at least one snap and a second surface at the distal end of at least one snap, the first surface being configured to engage the distal end of a locking feature on one of the plunger engagement sleeve and the plunger engagement post during plunger engagement with piston, and the second surface being configured to engage the proximal end of a locking feature on one of the plunger engagement sleeve and the plunger engagement post during plunger disengagement from piston.

[0012] According to some embodiments, at least one snap-fit ​​may project radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis or radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis. At least one snap-fit ​​may define a locking recess for receiving at least a portion of the plunger engagement mechanism when the plunger is connected to the piston. At least one snap-fit ​​may project radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis, and at least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove projecting radially inward from the outer surface of the plunger engagement post.

[0013] According to some embodiments, the plunger body may have a conical portion at its distal end and a cylindrical portion at its proximal end. At least one retaining member may project proximally from the inner surface of the conical portion. A plurality of release tabs may project radially inward or proximally from the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with a plunger engagement sleeve to release the plunger from the piston as the plunger rotates about a central longitudinal axis. The proximal end of each of the plurality of release tabs may have a sharp guide surface.

[0014] According to some embodiments, the plunger cap may cover at least a portion of the distal surface of the plunger body and may include a seal disposed around at least a portion of the circumferential sidewall of the plunger body.

[0015] According to some embodiments, the plunger may be configured to be slidably positioned within the barrel of the syringe. The plunger may be configured to reciprocate within the barrel of the syringe.

[0016] According to some embodiments, a fluid injector system may include: at least one reciprocating piston having a piston head; and a plunger engagement mechanism associated with the piston head and configured to engage a plunger of a syringe connected to the fluid injector system to reciprocately drive the plunger in the syringe due to movement of at least one piston. The plunger engagement mechanism may include: a plunger engagement sleeve having a hollow body; a plunger engagement post receivable within the hollow body of the plunger engagement sleeve; and an actuator operatively connected to one of the plunger engagement sleeve and the plunger engagement post and configured to move one of the plunger engagement sleeve and the plunger engagement post between an engaged position and a disengaged position, wherein, in the engaged position, the plunger engagement post may be positioned within the hollow body of the plunger engagement sleeve to capture at least one resilient flexible retaining member associated with the plunger in a receiving space between the plunger engagement sleeve and the plunger engagement post, and wherein, in the disengaged position, the plunger engagement post may be positioned at least partially outside the hollow body of the plunger engagement sleeve to allow at least one resilient flexible retaining member of the plunger to be flexibly inserted into or removed from the receiving space.

[0017] According to some embodiments, the actuator may be a rotary electric motor, a linear electric motor, a linear actuator, or a solenoid. According to some embodiments, the actuator may be manually operated. The actuator may have an engaged state for moving one of the plunger engagement sleeve and the plunger engagement pin to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and the plunger engagement pin to a disengaged position. The actuator automatically moves to the disengaged state during actuator de-energization. The actuator may be in the engaged state only during proximal movement of at least one piston. At least one biasing element may be configured to move the actuator from the engaged state to the disengaged state.

[0018] According to some embodiments, rotational movement of the actuator can move one of the plunger engagement sleeve and the plunger engagement post proximally or distally in a linear direction. According to some embodiments, linear movement of the actuator can move one of the plunger engagement sleeve and the plunger engagement post proximally or distally in a linear direction. The actuator can be operatively connected to a controller configured to control the actuation of the actuator.

[0019] According to some embodiments, one of the plunger engagement sleeve and the plunger engagement ring can be linearly or rotatably movable relative to the piston, while the other of the plunger engagement sleeve and the plunger engagement ring can be stationary relative to the piston. The plunger engagement pin and the plunger engagement ring can be linearly or rotatably movable relative to the piston.

[0020] According to some embodiments, at least one sensor may be configured to detect the position of at least one of the plunger engagement collar and the plunger engagement post between an engaged position and a disengaged position. A plunger detection sensor may be configured to detect the presence of at least one retaining member of the plunger in a receiving space between the plunger engagement collar and the plunger engagement post.

[0021] According to some embodiments, the hollow body of the plunger engagement sleeve may have an opening having a stepped inner diameter that decreases in the direction from the distal end to the proximal end of the plunger engagement sleeve. The plunger engagement post may include a locking groove projecting radially inward from the outer surface of the plunger engagement post, and the locking groove may be configured to receive at least one snap on at least one retaining member of the plunger. The distal edge of the locking groove may be configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one snap of at least one retaining member from engagement with the locking groove when one of the plunger engagement sleeve and the plunger engagement post can be moved to a disengaged position. The plunger engagement post may have a body having a stepped outer diameter that decreases in the direction from the distal end to the proximal end of the plunger engagement post.

[0022] According to some embodiments, the plunger engagement collar may include a locking feature projecting radially inward from the inner surface of the plunger engagement collar. The locking feature may be configured to engage at least one latch on at least one retaining member of the plunger when one of the plunger engagement sleeve and the plunger engagement pin is movable to an engaged position. The locking feature may be configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one latch of the at least one retaining member from engagement with the locking feature when one of the plunger engagement sleeve and the plunger engagement pin is movable to a disengaged position.

[0023] According to some embodiments, the fluid injector system may also include a syringe having: a barrel having a proximal end, a distal end having a discharge nozzle, and a barrel sidewall extending between the proximal and distal ends; and a plunger slidably disposed within the barrel and capable of reciprocating between the proximal and distal ends.

[0024] According to some embodiments, the plunger may include: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and at least one retaining member associated with and extending proximally from the plunger body.

[0025] According to some embodiments, at least one retaining member may include: a first end connected to a plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one latch on the second end, wherein the at least one retaining member may have an outer surface configured to engage a plunger engagement sleeve when the plunger is engageable with a piston, wherein the at least one retaining member may have an inner surface configured to engage a plunger engagement post when the plunger is engageable with a piston, wherein the at least one latch may be configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger is engageable with a piston to prevent axial movement of the plunger relative to the piston, and wherein the at least one latch may be configured to radially deflect the second end of the at least one retaining member due to contact between the at least one latch and the locking feature when the piston moves axially relative to the plunger in a disengaged state.

[0026] According to some embodiments, the plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector. At least one snap-fit ​​is radially inwardly projecting from the inner surface of at least one retaining member in a direction toward the central longitudinal axis. At least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove radially inwardly projecting from the outer surface of the plunger engagement post.

[0027] According to some embodiments, at least one latch may protrude radially inward from the inner surface of at least one retaining member in a direction toward the central longitudinal axis. According to some embodiments, at least one latch may protrude radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis.

[0028] According to some embodiments, the plunger body may have a conical portion at its distal end and a cylindrical portion at its proximal end. At least one retaining member may project proximally from the inner surface of the conical portion. A plurality of release tabs may project radially inward from the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with a plunger engagement sleeve to release the plunger from the piston as the plunger rotates about a central longitudinal axis. The proximal end of each of the plurality of release tabs may have a sharp guide surface.

[0029] According to some embodiments, a fluid injector system may include: at least one reciprocating piston having a piston head; and a plunger engagement mechanism associated with the piston head and configured to engage a plunger connected to a syringe of the fluid injector system to reciprocately drive the plunger in the syringe due to movement of at least one piston. The plunger engagement mechanism includes: a plunger engagement sleeve having a hollow body with a longitudinal axis; and a plunger engagement pin retractable within the hollow body of the plunger engagement sleeve and axially movable relative to the plunger engagement sleeve between an engagement position and a disengagement position, wherein the plunger engagement sleeve is rotatable about the longitudinal axis between a first position and a second position, and wherein the plunger engagement pin can be axially moved along the longitudinal axis from the engagement position to the disengagement position by rotation of the plunger engagement sleeve.

[0030] According to some embodiments, the plunger engagement pin can be axially moved from the proximal end of the piston toward the distal end of the piston. The plunger release sleeve may include a plurality of plunger release teeth projecting radially outward from the outer surface of the hollow body. The plurality of plunger release teeth may be configured to engage a plurality of release tabs on the plunger, such that rotation of the plunger about its longitudinal axis causes rotation of the plunger engagement sleeve about its longitudinal axis.

[0031] According to some embodiments, a plunger release sleeve may surround at least a portion of a plunger engagement sleeve, wherein the plunger release sleeve may be configured to rotate about a longitudinal axis as the plunger engagement sleeve rotates. The plunger release sleeve may include an opening having an inclined surface that is angled relative to the longitudinal axis in a direction from the distal end of the plunger release sleeve toward the proximal end of the plunger release sleeve.

[0032] According to some embodiments, the plunger engagement post may have a guide pin extending in a direction perpendicular to the longitudinal axis, wherein the guide pin may be received within an opening of the plunger release sleeve. Rotation of the plunger engagement sleeve may cause a corresponding rotation of the plunger release sleeve. The guide pin may be guided along an inclined surface from a proximal end of the inclined surface toward a distal end of the inclined surface, thereby moving the plunger engagement post from an engaged position to a disengaged position.

[0033] According to some embodiments, the biasing member can be operatively connected to the plunger engagement sleeve and the plunger engagement post. The biasing member can be configured to bias the plunger engagement sleeve to a first position.

[0034] According to some embodiments, an actuator is operatively connected to a plunger engagement post and configured to move the plunger engagement post between an engaged position and a disengaged position. In the engaged position, the plunger engagement post is positioned within the hollow body of a plunger engagement sleeve and configured to capture at least one resilient flexible retaining member associated with the plunger in a receiving space between the plunger engagement collar and the plunger engagement post. In the disengaged position, the plunger engagement post is at least partially positioned outside the hollow body of the plunger engagement sleeve to allow at least one resilient flexible retaining member of the plunger to flexibly insert or remove from the receiving space.

[0035] According to some embodiments, the actuator may be a rotary electric motor, a linear electric motor, a linear actuator, or a solenoid. According to some embodiments, the actuator may be manually operated. The actuator may have an engaged state for moving one of the plunger engagement sleeve and the plunger engagement pin to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and the plunger engagement pin to a disengaged position. During actuator de-energization, the actuator may automatically move to the disengaged state. The actuator may be in the engaged state only during the proximal movement of at least one piston.

[0036] According to some embodiments, at least one biasing element is used to move the actuator from an engaged state to a disengaged state. Rotation or linear movement of the actuator causes one of the plunger engagement sleeve and plunger engagement post to move proximally or distally in a linear direction. The actuator may be operatively connected to a controller configured to control the actuation of the actuator.

[0037] According to some embodiments, at least one sensor may be configured to detect the position of at least one of the plunger engagement collar and the plunger engagement post between an engaged position and a disengaged position. A plunger detection sensor may be configured to detect the presence of at least one retaining member of the plunger in a receiving space between the plunger engagement collar and the plunger engagement post.

[0038] According to some embodiments, the hollow body of the plunger engagement sleeve may have an opening having a stepped inner diameter that decreases in the direction from the distal end to the proximal end of the plunger engagement sleeve. The plunger engagement post may include a locking groove projecting radially inward from the outer surface of the plunger engagement post, wherein the locking groove may be configured to receive at least one snap on at least one retaining member of the plunger. The distal edge of the locking groove may be configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one snap of at least one retaining member from engagement with the locking groove when one of the plunger engagement sleeve and the plunger engagement post can be moved to a disengaged position.

[0039] According to some embodiments, the fluid injector system may also include a syringe having: a barrel having a proximal end, a distal end having a discharge nozzle, and a barrel sidewall extending between the proximal and distal ends; and a plunger slidably disposed within the barrel and reciprocating between the proximal and distal ends.

[0040] According to some embodiments, the plunger may include: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and at least one retaining member associated with and extending proximally from the plunger body.

[0041] According to some embodiments, at least one retaining member may include: a first end connected to a plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one latch on the second end, wherein the at least one retaining member may have an outer surface configured to engage a plunger engagement sleeve when the plunger engages with a piston, wherein the at least one retaining member may have an inner surface configured to engage a plunger engagement post when the plunger engages with a piston, wherein the at least one latch may be configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger is engageable with a piston to prevent axial movement of the plunger relative to the piston, and wherein the at least one latch is configured to radially deflect the second end of the at least one retaining member due to contact between the at least one latch and the locking feature when the piston moves axially relative to the plunger in a disengaged state.

[0042] According to some embodiments, the plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector.

[0043] According to some embodiments, at least one snap-fit ​​may protrude radially inward from the inner surface of at least one retaining member in a direction toward the central longitudinal axis, and at least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove protruding radially inward from the outer surface of the plunger engagement post.

[0044] According to some embodiments, at least one latch may project radially inward from the inner surface of at least one retaining member in a direction toward the central longitudinal axis, or at least one latch may project radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis. At least one latch may define a locking recess for receiving at least a portion of the plunger engagement mechanism when the plunger is connectable to the piston.

[0045] According to some embodiments, the plunger body may have a conical portion at its distal end and a cylindrical portion at its proximal end. At least one retaining member may project proximally from the inner surface of the conical portion. A plurality of release tabs may project radially inward or proximally from the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with a plunger engagement sleeve to release the plunger from the piston as the plunger rotates about a central longitudinal axis. The proximal end of each of the plurality of release tabs may have a sharp guide surface.

[0046] Other embodiments or aspects of this disclosure are described in the following numbered clauses:

[0047] Clause 1. A plunger for use with a syringe, the plunger comprising: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and at least one retaining member associated with and extending proximally from the plunger body, the at least one retaining member comprising: a first end connected to the plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one snap on the second end, wherein the at least one retaining member has an outer surface configured to engage a plunger contact on a piston of a fluid injector system when the plunger is in a locked state with a piston. A plunger engagement sleeve for a coupling mechanism, wherein at least one retaining member has an inner surface configured to engage a plunger engagement post of the plunger engagement mechanism when the plunger is in a locked state with the piston, wherein at least one snap is configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger is in a locked state with the piston to prevent axial movement of the plunger relative to the piston, and wherein at least one snap is configured to cause a second end of at least one retaining member to radially deflect when the piston moves axially relative to the plunger in an unlocked state due to engagement of at least one snap with the locking feature on one of the plunger engagement sleeve and the plunger engagement post.

[0048] Clause 2. The plunger according to Clause 1, wherein at least one retaining member comprises a plurality of retaining members spaced apart around a central longitudinal axis.

[0049] Clause 3. The plunger as described in Clause 2, wherein a plurality of retaining members are spaced apart at equal intervals around a central longitudinal axis.

[0050] Clause 4. The plunger according to any one of Clauses 1 to 3, wherein at least one retaining member extends proximally in a direction parallel to the central longitudinal axis.

[0051] Clause 5. The plunger according to any one of Clauses 1 to 3, wherein at least one retaining member extends proximally in a direction angled relative to the longitudinal axis.

[0052] Clause 6. The plunger according to any one of Clauses 1 to 5, wherein at least one retaining member is linearly adjacent between the first end and the second end.

[0053] Clause 7. The plunger according to any one of Clauses 1 to 5, wherein at least one retaining member is flexurally abutted between the first end and the second end.

[0054] Clause 8. The plunger according to any one of Clauses 1 to 7, wherein the plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector.

[0055] Clause 9. The plunger according to any one of Clauses 1 to 8, wherein at least one latch has a first surface at the proximal end of the at least one latch and a second surface at the distal end of the at least one latch, the first surface being configured to engage the distal end of a locking feature on one of the plunger engagement sleeve and the plunger engagement post during engagement of the plunger with the piston, and the second surface being configured to engage the proximal end of a locking feature on one of the plunger engagement sleeve and the plunger engagement post during disengagement of the plunger from the piston.

[0056] Clause 10. The plunger according to any one of Clauses 1 to 9, wherein at least one latch protrudes radially inward from the inner surface of at least one retaining member in a direction toward the central longitudinal axis.

[0057] Clause 11. The plunger according to any one of Clauses 1 to 10, wherein at least one latch protrudes radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis.

[0058] Clause 12. The plunger according to any one of Clauses 1 to 11, wherein at least one snap defines a locking recess for receiving at least a portion of the plunger engagement mechanism when the plunger is connected to the piston.

[0059] Clause 13. The plunger according to any one of Clauses 1 to 12, wherein at least one snap-fit ​​protrudes radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis, and wherein at least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove protruding radially inward from the outer surface of the plunger engagement post.

[0060] Clause 14. The plunger according to any one of Clauses 1 to 13, wherein the plunger body has a conical portion at the distal end and a cylindrical portion at the proximal end.

[0061] Clause 15. The plunger according to Clause 14, wherein at least one retaining member protrudes proximally from the inner surface of the conical portion.

[0062] Clause 16. The plunger according to Clause 14 or 15 further includes a plurality of release tabs projecting radially inward from the inner surface of the cylindrical portion or proximal to the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with the plunger engagement sleeve to achieve release of the plunger from the piston as the plunger rotates about a central longitudinal axis.

[0063] Clause 17. The plunger as described in Clause 16, wherein the proximal end of each of the plurality of release tabs has a sharp guiding surface.

[0064] Clause 18. The plunger according to any one of Clauses 1 to 17 further includes a plunger cap that covers at least a portion of the distal surface of the plunger body and includes a seal disposed around at least a portion of the circumferential sidewall of the plunger body.

[0065] Clause 19. The plunger according to any one of Clauses 1 to 18, wherein the plunger is configured to be slidably positioned within the barrel of the syringe.

[0066] Clause 20. The plunger as described in Clause 19, wherein the plunger is configured to reciprocate within the barrel of the syringe.

[0067] Clause 21. A fluid injector system comprising: at least one reciprocating piston having a piston head; and a plunger engagement mechanism associated with the piston head and configured to engage a plunger connected to a syringe connected to the fluid injector system to reciprocately drive the plunger in the syringe due to movement of at least one piston, the plunger engagement mechanism comprising: a plunger engagement sleeve having a hollow body; a plunger engagement post receivable within the hollow body of the plunger engagement sleeve; and an actuator operatively connected to one of the plunger engagement sleeve and the plunger engagement post and configured to move one of the plunger engagement sleeve and the plunger engagement post between an engaged position and a disengaged position, wherein, in the engaged position, the plunger engagement post is positioned within the hollow body of the plunger engagement sleeve to capture at least one resilient flexible retaining member associated with the plunger in a receiving space between the plunger engagement sleeve and the plunger engagement post, and wherein, in the disengaged position, the plunger engagement post is at least partially positioned outside the hollow body of the plunger engagement sleeve to allow at least one resilient flexible retaining member of the plunger to be flexibly inserted into or removed from the receiving space.

[0068] Clause 22. The fluid injector system as described in Clause 21, wherein the actuator is a rotary electric motor, a linear electric motor, a linear actuator, or a solenoid.

[0069] Clause 23. The fluid injector system as described in Clause 21, wherein the actuator is manually operated.

[0070] Clause 24. The fluid injector system according to any one of Clauses 21 to 23, wherein the actuator has an engaged state for moving one of the plunger engagement sleeve and the plunger engagement post to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and the plunger engagement post to a disengaged position.

[0071] Clause 25. A fluid injector system according to any one of Clauses 21 to 24, wherein the actuator automatically moves to a disengaged state during actuator de-energization.

[0072] Clause 26. A fluid injector system according to any one of Clauses 21 to 25, wherein the actuator is engaged only during the proximal movement of at least one piston.

[0073] Clause 27. The fluid injector system according to any one of Clauses 21 to 26 further includes at least one biasing element for moving the actuator from an engaged state to a disengaged state.

[0074] Clause 28. A fluid injector system according to any one of Clauses 21 to 27, wherein rotational movement of the actuator causes one of the plunger engagement sleeve and the plunger engagement post to move proximally or distally in a linear direction.

[0075] Clause 29. A fluid injector system according to any one of Clauses 21 to 28, wherein linear movement of the actuator causes one of the plunger engagement sleeve and the plunger engagement post to move proximally or distally in a linear direction.

[0076] Clause 30. A fluid injector system according to any one of Clauses 21 to 29, wherein the actuator is operatively connected to a controller configured to control the actuation of the actuator.

[0077] Clause 31. A fluid injector system according to any one of Clauses 21 to 30, wherein one of the plunger engagement sleeve and the plunger engagement sleeve is linearly or rotatably movable relative to the piston, while the other of the plunger engagement sleeve and the plunger engagement sleeve is stationary relative to the piston.

[0078] Clause 32. A fluid injector system according to any one of Clauses 21 to 31, wherein the plunger engagement post and the plunger engagement collar are linearly or rotatably movable relative to the piston.

[0079] Clause 33. The fluid injector system according to any one of Clauses 21 to 32 further includes at least one sensor configured to detect the position of at least one of the plunger engagement collar and the plunger engagement post between an engaged position and a disengaged position.

[0080] Clause 34. The fluid injector system according to any one of Clauses 21 to 33 further includes a plunger detection sensor configured to detect the presence of at least one retaining member of the plunger in the receiving space between the plunger engagement collar and the plunger engagement post.

[0081] Clause 35. The fluid injector system according to any one of Clauses 21 to 34, wherein the hollow body of the plunger engagement sleeve has an opening having a stepped inner diameter that decreases in the direction from the distal end of the plunger engagement sleeve to the proximal end of the plunger engagement sleeve.

[0082] Clause 36. The fluid injector system according to any one of Clauses 21 to 35, wherein the plunger engagement post includes a locking groove projecting radially inward from the outer surface of the plunger engagement post, and wherein the locking groove is configured to receive at least one snap on at least one retaining member of the plunger.

[0083] Clause 37. The fluid injector system according to Clause 36, wherein the distal edge of the locking groove is configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one latch of at least one retaining member from engagement with the locking groove when one of the plunger engagement sleeve and the plunger engagement post moves to a disengaged position.

[0084] Clause 38. A fluid injector system according to any one of Clauses 21 to 37, wherein the plunger engagement post has a body having a stepped outer diameter that decreases in the direction from the distal end of the plunger engagement post to the proximal end of the plunger engagement post.

[0085] Clause 39. The fluid injector system according to any one of Clauses 21 to 38, wherein the plunger engagement collar includes a locking feature that projects radially inward from the inner surface of the plunger engagement collar, and wherein the locking feature is configured to engage at least one latch on at least one retaining member of the engagement plunger when one of the plunger engagement sleeve and the plunger engagement pin is moved to the engagement position.

[0086] Clause 40. The fluid injector system according to Clause 39, wherein the locking feature is configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one latch of at least one retaining member from engagement with the locking feature when one of the plunger engagement sleeve and the plunger engagement post moves to a disengaged position.

[0087] Clause 41. The fluid injector system according to any one of Clauses 21 to 39 further includes a syringe comprising: a barrel having a proximal end, a distal end having a discharge nozzle, and a barrel sidewall extending between the proximal and distal ends; and a plunger slidably disposed within the barrel and reciprocating between the proximal and distal ends.

[0088] Clause 42. The fluid injector system according to Clause 41, wherein the plunger comprises: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and at least one retaining member associated with and extending proximally from the plunger body.

[0089] Clause 43. The fluid injector system according to Clause 41 or 42, wherein at least one retaining member comprises: a first end connected to a plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one latch on the second end, wherein the at least one retaining member has an outer surface configured to engage a plunger engagement sleeve when the plunger engages with a piston, wherein the at least one retaining member has an inner surface configured to engage a plunger engagement post when the plunger engages with a piston, wherein the at least one latch is configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger engages with a piston to prevent axial movement of the plunger relative to the piston, and wherein the at least one latch is configured to radially deflect the second end of the at least one retaining member due to contact between the at least one latch and the locking feature when the piston moves axially relative to the plunger in a disengaged state.

[0090] Clause 44. A fluid injector system according to any one of Clauses 41 to 43, wherein the plungers are configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector.

[0091] Clause 45. The fluid injector system according to any one of Clauses 41 to 44, wherein at least one snap-fit ​​protrudes radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis, and wherein at least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove protruding radially inward from the outer surface of the plunger engagement post.

[0092] Clause 46. The fluid injector system according to any one of Clauses 41 to 45, wherein at least one latch protrudes radially inward from the inner surface of at least one retaining member in a direction toward the central longitudinal axis, or wherein at least one latch protrudes radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis.

[0093] Clause 47. A fluid injector system according to any one of Clauses 41 to 46, wherein the plunger body has a conical portion at the distal end and a cylindrical portion at the proximal end.

[0094] Clause 48. The fluid injector system according to Clause 47, wherein at least one retaining member protrudes proximally from the inner surface of the conical portion.

[0095] Clause 49. The fluid injector system according to Clause 47 or 48 further includes a plurality of release tabs projecting radially inward from the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with a plunger engagement sleeve to release the plunger from the piston as the plunger rotates about a central longitudinal axis.

[0096] Clause 50. The fluid injector system according to Clause 49, wherein each of the plurality of release tabs has a sharp guiding surface at its proximal end.

[0097] Clause 51. A fluid injector system comprising: at least one reciprocating piston having a piston head; and a plunger engagement mechanism associated with the piston head and configured to engage a plunger of a syringe connected to the fluid injector system to reciprocately drive the plunger in the syringe due to movement of at least one piston, the plunger engagement mechanism comprising: a plunger engagement sleeve having a hollow body with a longitudinal axis; and a plunger engagement pin retractable within the hollow body of the plunger engagement sleeve and axially movable relative to the plunger engagement sleeve between an engaged position and a disengaged position, wherein the plunger engagement sleeve is rotatable about the longitudinal axis between a first position and a second position, and wherein the plunger engagement pin is axially moved along the longitudinal axis from the engaged position to the disengaged position by rotation of the plunger engagement sleeve.

[0098] Clause 52. The fluid injector system according to Clause 51, wherein the plunger engagement post is axially movable from the proximal end of the piston toward the distal end of the piston.

[0099] Clause 53. The fluid injector system according to Clause 51 or 52, wherein the plunger release sleeve includes a plurality of plunger release teeth projecting radially outward from the outer surface of the hollow body.

[0100] Clause 54. The fluid injector system according to Clause 53, wherein a plurality of plunger release teeth are configured to engage a plurality of release tabs on the plunger such that rotation of the plunger about the longitudinal axis of the plunger causes rotation of the plunger engagement sleeve about the longitudinal axis.

[0101] Clause 55. The fluid injector system according to any one of Clauses 51 to 54 further includes a plunger release sleeve surrounding at least a portion of the plunger engagement sleeve, wherein the plunger release sleeve is configured to rotate about a longitudinal axis as the plunger engagement sleeve rotates.

[0102] Clause 56. The fluid injector system according to any one of Clauses 51 to 55, wherein the plunger release sleeve includes an opening having an inclined surface that is angled relative to the longitudinal axis in a direction from the distal end of the plunger release sleeve toward the proximal end of the plunger release sleeve.

[0103] Clause 57. The fluid injector system according to Clause 56, wherein the plunger engagement post has a guide pin extending in a direction perpendicular to the longitudinal axis, and wherein the guide pin is received within an opening in the plunger release sleeve.

[0104] Clause 58. The fluid injector system according to Clause 57, wherein rotation of the plunger engagement sleeve causes a corresponding rotation of the plunger release sleeve, and wherein a guide pin is guided along an inclined surface from the proximal end of the inclined surface toward the distal end, thereby moving the plunger engagement pin from the engaged position to the disengaged position.

[0105] Clause 59. The fluid injector system according to any one of Clauses 51 to 58 further includes a biasing member operatively connected to the plunger engagement sleeve and the plunger engagement post.

[0106] Clause 60. The fluid injector system according to Clause 59, wherein the biasing member is configured to bias the plunger engagement sleeve to a first position.

[0107] Clause 61. The fluid injector system according to any one of Clauses 51 to 60 further includes an actuator operatively connected to the plunger engagement post and configured to move the plunger engagement post between an engaged position and a disengaged position.

[0108] Clause 62. The fluid injector system according to Clause 61, wherein, in the engaged position, the plunger engagement post is positioned within the hollow body of the plunger engagement sleeve and configured to capture at least one resilient flexible retaining member associated with the plunger in a receiving space between the plunger engagement collar and the plunger engagement post, and wherein, in the disengaged position, the plunger engagement post is at least partially positioned outside the hollow body of the plunger engagement sleeve to allow at least one resilient flexible retaining member of the plunger to be flexibly inserted into or removed from the receiving space.

[0109] Clause 63. The fluid injection system according to Clause 61 or 62, wherein the actuator is a rotary electric motor, a linear electric motor, a linear actuator, or a solenoid.

[0110] Clause 64. The fluid injector system according to any one of Clauses 61 to 63, wherein the actuator is manually operated.

[0111] Clause 65. The fluid injector system according to any one of Clauses 61 to 63, wherein the actuator has an engaged state for moving one of the plunger engagement sleeve and the plunger engagement post to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and the plunger engagement post to a disengaged position.

[0112] Clause 66. A fluid injector system according to any one of Clauses 61 to 65, wherein the actuator automatically moves to a disengaged state during a power outage.

[0113] Clause 67. A fluid injector system according to any one of Clauses 61 to 66, wherein the actuator is engaged only during the proximal movement of at least one piston.

[0114] Clause 68. The fluid injector system according to any one of Clauses 61 to 67 further includes at least one biasing element for moving the actuator from an engaged state to a disengaged state.

[0115] Clause 69. A fluid injector system according to any one of Clauses 61 to 68, wherein rotational movement of the actuator causes one of the plunger engagement sleeve and the plunger engagement post to move proximally or distally in a linear direction.

[0116] Clause 70. A fluid injector system according to any one of Clauses 61 to 69, wherein linear movement of the actuator causes one of the plunger engagement sleeve and the plunger engagement post to move proximally or distally in a linear direction.

[0117] Clause 71. A fluid injector system according to any one of Clauses 61 to 70, wherein the actuator is operatively connected to a controller configured to control the actuation of the actuator.

[0118] Clause 72. The fluid injector system according to any one of Clauses 51 to 71 further includes at least one sensor configured to detect the position of at least one of the plunger engagement collar and the plunger engagement post between an engaged position and a disengaged position.

[0119] Clause 73. The fluid injector system according to any one of Clauses 51 to 72 further includes a plunger detection sensor configured to detect the presence of at least one retaining member of the plunger in the receiving space between the plunger engagement collar and the plunger engagement post.

[0120] Clause 74. The fluid injector system according to any one of Clauses 51 to 73, wherein the hollow body of the plunger engagement sleeve has an opening having a stepped inner diameter that decreases in the direction from the distal end of the plunger engagement sleeve to the proximal end of the plunger engagement sleeve.

[0121] Clause 75. The fluid injector system according to any one of Clauses 51 to 74, wherein the plunger engagement post includes a locking groove projecting radially inward from the outer surface of the plunger engagement post, and wherein the locking groove is configured to receive at least one snap on at least one retaining member of the plunger.

[0122] Clause 76. The fluid injector system according to Clause 75, wherein the distal edge of the locking groove is configured to flexibly deflect at least one retaining member of the plunger during axial movement of the plunger relative to the piston, so as to disengage at least one latch of at least one retaining member from engagement with the locking groove when one of the plunger engagement sleeve and the plunger engagement post moves to a disengaged position.

[0123] Clause 77. The fluid injector system according to any one of Clauses 51 to 76 further includes a syringe comprising: a barrel having a proximal end, a distal end having a discharge nozzle, and a barrel sidewall extending between the proximal and distal ends; and a plunger slidably disposed within the barrel and reciprocating between the proximal and distal ends.

[0124] Clause 78. The fluid injector system according to Clause 77, wherein the plunger comprises: a plunger body defining a central longitudinal axis and having a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and at least one retaining member associated with and extending proximally from the plunger body.

[0125] Clause 79. The fluid injector system according to Clause 77 or 78, wherein at least one retaining member comprises: a first end connected to a plunger body; a second end adjacent to and radially resiliently deflectable relative to the first end; and at least one latch on the second end, wherein the at least one retaining member has an outer surface configured to engage a plunger engagement sleeve when the plunger engages with a piston, wherein the at least one retaining member has an inner surface configured to engage a plunger engagement post when the plunger engages with a piston, wherein the at least one latch is configured to engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger engages with a piston to prevent axial movement of the plunger relative to the piston, and wherein the at least one latch is configured to radially deflect the second end of the at least one retaining member due to contact between the at least one latch and the locking feature when the piston moves axially relative to the plunger in a disengaged state.

[0126] Clause 80. A fluid injector system according to any one of Clauses 77 to 79, wherein the plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector.

[0127] Clause 81. The fluid injector system according to any one of Clauses 77 to 80, wherein at least one snap-fit ​​protrudes radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis, and wherein at least one snap-fit ​​is configured to be received within a locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove protruding radially inward from the outer surface of the plunger engagement post.

[0128] Clause 82. The fluid injector system according to any one of Clauses 77 to 81, wherein at least one latch protrudes radially inward from the inner surface of at least one retaining member in a direction toward a central longitudinal axis, or wherein at least one latch protrudes radially outward from the outer surface of at least one retaining member in a direction away from a central longitudinal axis.

[0129] Clause 83. A fluid injector system according to any one of Clauses 77 to 82, wherein at least one latch protrudes radially outward from the outer surface of at least one retaining member in a direction away from the central longitudinal axis.

[0130] Clause 84. A fluid injector system according to any one of Clauses 77 to 83, wherein the plunger body has a conical portion at the distal end and a cylindrical portion at the proximal end.

[0131] Clause 85. The fluid injector system according to Clause 84, wherein at least one retaining member protrudes proximally from the inner surface of the conical portion.

[0132] Clause 86. The fluid injector system according to Clause 84 or 85 further includes a plurality of release tabs that project radially inward from the inner surface of the cylindrical portion or proximal from the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with a plunger engagement sleeve to achieve release of the plunger from the piston as the plunger rotates about a central longitudinal axis.

[0133] Clause 87. The fluid injector system according to Clause 86, wherein each of the plurality of release tabs has a sharp guiding surface at its proximal end.

[0134] These and other features and characteristics of syringes, syringe plungers, pressure jackets, and systems having syringes and / or syringe plungers, as well as the methods of operation and function of related structural elements, the combination of parts, and the economy of manufacture, will become more apparent upon consideration of the following description and appended claims with reference to the accompanying drawings, all of which form part of this specification, wherein like reference numerals denote corresponding parts in the figures. However, it should be clearly understood that the drawings are for illustrative and descriptive purposes only. Attached Figure Description

[0135] Figure 1 A perspective view of a fluid injector system according to an embodiment of the present disclosure;

[0136] Figure 2 for Figure 1 A schematic diagram of a fluid injector system;

[0137] Figure 3 A perspective view of a fluid injector system according to another embodiment of this disclosure;

[0138] Figure 4 A schematic diagram of a controller for a fluid injector system according to an embodiment of the present disclosure;

[0139] Figure 5A A perspective view of a syringe according to an embodiment of the present disclosure;

[0140] Figure 5B for Figure 5A A cross-sectional view of the syringe, showing the plunger located inside the syringe barrel;

[0141] Figure 6 An exploded perspective view of a plunger according to an embodiment of the present disclosure;

[0142] Figure 7 for Figure 6 A perspective view of the cross-section of the plunger support ring;

[0143] Figure 8A A cross-sectional perspective view of a plunger support ring according to another embodiment of the present disclosure;

[0144] Figure 8B A cross-sectional perspective view of a plunger support ring according to another embodiment of the present disclosure;

[0145] Figure 8C A cross-sectional perspective view of a plunger support ring according to another embodiment of the present disclosure;

[0146] Figure 9 A perspective cross-sectional view of the piston of a plunger engagement mechanism according to an embodiment of the present disclosure;

[0147] Figure 10A for Figure 9 A perspective view of the plunger engagement sleeve of the plunger engagement mechanism shown;

[0148] Figure 10B for Figure 10A A cross-sectional view of the plunger engagement sleeve shown;

[0149] Figure 11A for Figure 9 A perspective view of the actuator and plunger release sleeve of the plunger engagement mechanism shown.

[0150] Figure 11B for Figure 11A Cross-sectional view of the actuator and plunger release sleeve shown;

[0151] Figure 12 for Figure 9 and 13A -13J shows a perspective view of the plunger engagement column of the plunger engagement mechanism.

[0152] Figure 13A-13J for Figure 9 A perspective cross-sectional view of the operation of the piston and plunger engagement mechanism;

[0153] Figure 14A-14C A cross-sectional view of the operation of the piston in a plunger engagement mechanism according to another embodiment of the present disclosure;

[0154] Figure 15 for Figure 14A-14C A perspective view of the plunger engagement column of the plunger engagement mechanism shown.

[0155] Figure 16 for Figure 14A-14C A perspective view of the plunger release sleeve of the plunger engagement mechanism shown.

[0156] Figure 17A and 17B for Figure 14A-14C Perspective view of the plunger engagement sleeve of the plunger engagement mechanism shown. Figure 17A ) and perspective cross-sectional view ( Figure 17B );

[0157] Figure 18A A perspective cross-sectional view of the operation of the piston in a plunger engagement mechanism according to another embodiment of the present disclosure;

[0158] Figure 18B for Figure 18A A perspective view of the plunger engagement column of the plunger engagement mechanism shown.

[0159] Figure 19 A perspective view of a piston in a fluid injector system having a plunger engagement mechanism according to another embodiment of the present disclosure;

[0160] Figure 20 for Figure 19 Exploded perspective view of the plunger engagement mechanism;

[0161] Figure 21A-21B for Figure 19 A cross-sectional view of the operation of the plunger engagement mechanism;

[0162] Figure 22A-22E A cross-sectional view of the operation of a plunger engagement mechanism according to another embodiment of the present disclosure;

[0163] Figure 23A-23G A cross-sectional view of the piston in operation of a plunger engagement mechanism according to another embodiment of the present disclosure;

[0164] Figure 24A A perspective view of a piston having a plunger engagement mechanism according to another embodiment of the present disclosure;

[0165] Figure 24B for Figure 24A Exploded view of the plunger engagement mechanism;

[0166] Figure 24C for Figure 24A A cross-sectional view of the piston and plunger engagement mechanism;

[0167] Figure 25A-25B A cross-sectional view of the piston in operation of a plunger engagement mechanism according to another embodiment of the present disclosure;

[0168] Figure 26 A perspective cross-sectional view of a piston in a fluid injector system having a plunger engagement mechanism according to another embodiment of the present disclosure;

[0169] Figure 27A-27B for Figure 26 Perspective view of the plunger engagement sleeve of the plunger engagement mechanism ( Figure 27A ) and perspective cross-sectional view ( Figure 27B );

[0170] Figure 28 for Figure 26 A perspective view of the plunger release sleeve of the plunger engagement mechanism;

[0171] Figure 29 for Figure 26 A perspective cross-sectional view of the plunger engagement column of the plunger engagement mechanism shown.

[0172] Figure 30A-30D for Figure 26 A perspective cross-sectional view of the engagement operation of the piston and plunger engagement mechanism, showing the plunger engagement mechanism at different stages during plunger engagement.

[0173] Figure 31A-31D for Figure 26 A perspective cross-sectional view of the piston and plunger engagement mechanism during disengagement, showing the plunger engagement mechanism at different stages during plunger disengagement.

[0174] Figure 32 A top view of a system including a fluid injector and a pressure sheath according to another embodiment of the present disclosure;

[0175] Figure 33 for Figure 32 A top-down view of the system's decomposed structure;

[0176] Figure 34 A perspective view of a pair of pressure sheaths according to another embodiment of the present disclosure;

[0177] Figure 35A A perspective view of a syringe cap according to another embodiment of the present disclosure; and

[0178] Figure 35B This is a perspective view of a syringe assembly according to another embodiment of the present disclosure. Detailed Implementation

[0179] For the purposes described below, the terms “up,” “down,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “horizontal,” “vertical,” and their derivatives should be used in relation to the orientation disclosed in the accompanying drawings. Spatial or directional terms, such as “left,” “right,” “inner,” “outer,” “up,” “down,” etc., should not be considered limiting, as the embodiments described herein can employ various alternative orientations.

[0180] As used herein, the singular forms of “a,” “an,” and “the” include plural indicators unless the context clearly specifies otherwise. All figures used in the specification and claims should, in all cases, be understood to be modified by the term “about.” The terms “approximately,” “about,” and “substantially” refer to a range of plus or minus ten percent of the specified value.

[0181] Unless otherwise stated, all ranges or ratios disclosed herein should be understood to encompass the starting and ending values, as well as any and all subranges or subratios contained therein. For example, the specified range or ratio of “1 to 10” should be considered to include any and all subranges or subratios between the minimum value of 1 and the maximum value of 10 (inclusive); that is, all subranges or subratios begin with a minimum value of 1 or greater and end with a maximum value of 10 or less. The ranges and / or ratios disclosed herein represent averages over the specified ranges and / or ratios.

[0182] As used herein, the term "at least one" is synonymous with "one or more." For example, the phrase "at least one of A, B, and C" means any one of A, B, and C, or any combination of any two or more of A, B, and C. For example, "at least one of A, B, and C" includes one or more individual A's; or one or more individual B's; or one or more individual C's; or one or more A's and one or more B's; or one or more A's and one or more C's; or one or more B's and one or more C's; or one or more of all A's, B's, and C's. Similarly, as used herein, the term "at least two" is synonymous with "two or more." For example, the phrase "at least two of D, E, and F" means any combination of any two or more of D's, E's, and F's. For example, "at least two of D, E, and F" includes one or more D's and one or more E's; or one or more D's and one or more F's; or one or more E's and one or more F's; or one or more of all D's, E's, and F's.

[0183] The terms “first,” “second,” etc., are not intended to refer to any particular order or sequence, but rather to different conditions, properties, or elements. All documents mentioned herein are incorporated herein by reference in their entirety. The term “at least” is synonymous with “greater than or equal to.” The term “not greater than” is synonymous with “less than or equal to.”

[0184] It should be understood that this disclosure may assume alternative variations and sequences of steps unless the opposite is expressly stated. It should also be understood that the specific apparatus and processes shown in the accompanying drawings and described in the following specification are merely exemplary aspects of this disclosure. Therefore, specific dimensions and other physical characteristics relating to the examples disclosed herein should not be considered limiting.

[0185] As used herein, the term “parallel” or “fundamentally parallel” refers to the relative angle between two objects (if extended to theoretical intersection), such as slender objects and including reference lines, i.e., from 0° to 5°, or from 0° to 3°, or from 0° to 2°, or from 0° to 1°, or from 0° to 0.5°, or from 0° to 0.25°, or from 0° to 0.1°, including the listed values.

[0186] As used herein, the term “perpendicular” or “nearly perpendicular” means that the relative angle between two objects at their actual or theoretical point of intersection is 85° to 90°, or 87° to 90°, or 88° to 90°, or 89° to 90°, or 89.5° to 90°, or 89.75° to 90°, or 89.9° to 90°, including the listed values.

[0187] When the term "distal" is used relative to a component of a fluid delivery system, such as a fluid reservoir, syringe, pressure sheath, or fluid line, it refers to the portion of that component closest to the patient. When used relative to a component of an injector system, such as a fluid reservoir, syringe, pressure sheath, or fluid line, the term "proximal" refers to the portion of that component closest to the injector of the injector system (i.e., the portion of that component furthest from the patient). When used relative to a component of a fluid delivery system, such as a fluid line, the term "upstream" refers to a direction away from the patient and towards the injector of the injector system. For example, if a first component is referred to as "upstream" of a second component, the first component is located closer to the injector than the second component. When used relative to a component of a fluid delivery system, such as a fluid line, the term "downstream" refers to a direction towards the patient and away from the injector of the fluid delivery system. For example, if a first component is referred to as "downstream" of a second component, the first component is located closer to the patient than the second component.

[0188] When the term "automatic" or "automatically" is used relative to the movement of one or more components of a fluid delivery system, such as a piston engagement mechanism associated with a piston, the term "automatic" or "automatically" means the movement of one or more components without manual assistance.

[0189] While the systems and apparatus described herein reference computed tomography (CT) angiography injection systems, CV angiography injection systems, positron emission tomography (PET) angiography injection systems, and magnetic resonance imaging (MRI) angiography injection systems, other pressurized injection protocols may also be incorporated into the various embodiments described herein for securing the syringe plunger to the piston of the fluid injector.

[0190] Referring to the accompanying drawings, wherein like reference numerals refer to the same parts in various views, this disclosure generally relates to a syringe plunger and a connection interface for connecting the syringe plunger to a piston of a fluid injector. Various embodiments relate to a syringe plunger that can be connected to and disconnected from a piston. In various embodiments, such a piston can be manually, mechanically, hydraulically, or electrically actuated. Furthermore, this disclosure provides a quick and simple solution for engaging and / or disengaging a syringe plunger from a piston without requiring a specific rotational orientation or alignment of the plunger relative to the piston. For example, the piston can be advanced forward until it engages the plunger, regardless of the plunger's orientation about its longitudinal axis relative to the piston's longitudinal axis, as will be described in more detail herein. Furthermore, when the piston can be attached to the plunger, a simple rotation of the plunger relative to the piston, for example by the rotation of the syringe about its longitudinal axis, can result in the separation of the two elements. In other embodiments, the engagement and disengagement of the piston and plunger can be performed by a fluid injector controller, for example, automatically as part of a programmed injection scheme during the initiation and completion of a fluid injection program, or initiated by the user, for example, through user input to the fluid injector controller. In further embodiments or aspects, this disclosure also relates generally to pressure sheaths and caps for pressure sheaths, wherein the same connection interface for connecting a syringe plunger to a piston of a fluid injector can be used to connect the pressure sheath to the fluid injector and / or to the cap of the pressure sheath itself.

[0191] refer to Figure 1 Non-limiting examples of a fluid injector system 10 (hereinafter referred to as "injector 10"), such as an automatic or powered fluid injector, are adapted to engage and actuate at least one syringe 12 and a corresponding plunger 26, each of which can be independently filled with a medical fluid F, such as contrast media, saline solution, or any desired medical fluid. Injector 10 can be used during a medical procedure to deliver fluid via at least one actuating member (e.g., at least one piston 13). Figure 2 As shown, the injector 10 drives the plunger 26 of at least one syringe 12 to inject medical fluid into a patient. The injector 10 can be a multi-syringe injector, wherein several syringes 12 may be oriented in a side-by-side or other configuration, and include plungers 26 separately actuated by corresponding pistons 13 associated with the injector 10. In embodiments having two syringes arranged side-by-side and filled with two different medical fluids, the injector 10 can deliver fluid from one or both syringes 12.

[0192] The injector 10 can be encapsulated within a housing 14 formed of a suitable structural material (e.g., plastic or metal). Depending on the desired application, the housing 14 can have various shapes and sizes. The injector 10 includes at least one syringe port 16 for connecting at least one syringe 12 to a corresponding piston 13. Figure 2 ).

[0193] At least one fluid pathway kit 17 may be fluidly connected to at least one syringe 12 for delivering medical fluid F from at least one syringe 12 to a catheter, needle, or other fluid delivery connector (not shown) inserted into a patient at a vascular access site. Fluid flow from at least one syringe 12 may be controlled by a controller 200. Figure 2 The controller 200 can operate various pistons, piston mechanical components (e.g., components for engagement and disengagement of the piston and plunger), valves, and / or flow regulating structures to regulate the delivery of medical fluids (e.g., saline solutions and contrast agents) to the patient based on user-selected injection parameters. One aspect of a suitable preloaded fluid injector is disclosed in U.S. Patent No. 5,383,858, which can be modified for use with the system described above, comprising at least one syringe and at least one piston for engagement and releasable retention with reference herein. Figures 1-2 The fluid injector described engages with the plunger of the syringe, and another aspect of a related multifluid delivery system that can be modified for use with this system can be found in U.S. Patent Nos. 7,553,294, 7,666,169, International Patent Application No. PCT / us 2012 / 037491, and U.S. Application Publication No. 2014 / 0027009; the disclosure of each patent is incorporated herein by reference. Other embodiments may include novel fluid injector systems designed to include various embodiments of a connection interface between the piston 13 of the injector 10 described herein and the plunger 26 of the syringe 12.

[0194] Reference Figure 3 A representative embodiment of a dual-injector angiography injector system 100 (hereinafter referred to as "injector 100") is illustrated. Injector 100 is configured to inject two medical fluids, such as an imaging contrast medium for angiography injection procedures, through a first fluid path 17A, and a second fluid path 17B, such as saline or Ringer's lactate, for flushing fluids. Injector 100 may include an injector housing 14 having two injector ports 16 configured to engage two injectors 12.

[0195] The injector housing 14 may also include at least one user interface 11 through which an operator can view and control the status of the injection process. The user interface 11 can be connected to a controller (similar to the controller 200 described herein). Figure 2 Operable communication. The controller sends commands to and receives commands from the user interface 11.

[0196] The injector 100 may also include at least one upstream air detector 240 for detecting one or more air bubbles within an air detection conduit region 250 of the first fluid path 17A and the second fluid path 17B. The air detection conduit region 250 may, for example, be associated with a proximal portion of the first fluid path 17A and the second fluid path 17B. At least one air detector 240 may include ultrasonic sensors and optical sensors, etc., configured to detect one or more air bubbles within the fluid paths.

[0197] Continue to refer to Figure 3 The injector 100 may further include bulk fluid containers 19A and 19B for filling and refilling the respective syringes 12 with imaging contrast media and flushing fluid, respectively. The bulk fluid containers 19A and 19B may be selectively fluidly connected to the syringes 12 via respective bulk fluid paths 21A and 21B and bulk fluid valves 23A and 23B.

[0198] Further details and examples of suitable non-limiting powered injector systems, including injectors, controllers, and air detectors, are described in U.S. Patent Nos. 5,383,858, 7,553,294, 7,666,169, 8,945,051, 10,022,493, and 10,507,319, the disclosures of which are incorporated herein by reference in their entirety. While injector 100 is described herein in the context of a dual-injector angiography (CV) injector, it should be understood that injector 100 can be adapted to single-injector and multi-injector configurations for any injection procedure, such as CT, PET, MRI, ultrasound, etc.

[0199] Injector 100 may include a piston, similar to that described herein. Figure 2 The piston 13 described herein is associated with each syringe 12. Each piston is configured to drive a corresponding plunger within the barrel of the respective syringe 12. Due to the high pressure associated with CV angiography, the syringe 12 can be inserted into a pressure sheath 15 to control the radial expansion of the syringe. A controller is operably associated with the piston to reciprocate the plunger within the syringe 12 and thereby perform the injection process.

[0200] The controller can be programmed or configured to perform a filling operation during which a piston associated with each syringe 12 is pulled back proximally to the syringe 12 to aspirate injection fluid (e.g., imaging contrast media and flushing fluid) from bulk fluid containers 19A, 19B into the syringe 12. During this filling operation, the controller can be programmed or configured to selectively actuate bulk fluid valves 23A and 23B to establish fluid communication between the respective syringe 12 and the bulk fluid containers 19A, 19B via bulk fluid paths 21A and 21B to control the filling of the syringe 12 with the appropriate injection fluid. Once the filling operation is completed, and optionally the infusion operation to remove any air from the syringe 12 (e.g., by infusing any such air back into the bulk fluid containers 19A, 19B or through the infusion tube), the controller can be programmed or configured to selectively actuate the bulk fluid valves 21A and 21B to block the fluid communication between the respective syringe 12 and the bulk fluid containers 19A, 19B via the bulk fluid paths 17A and 17B.

[0201] Following the filling and infusion operations, the controller can be programmed or configured to perform a delivery operation during which one or both pistons associated with syringe 12 move toward the distal end of syringe 12 to inject fluid into a first fluid path 17A and a second fluid path 17B. The controller can be programmed or configured to selectively actuate fluid valves 23A and 23B to establish fluid communication between syringe 12 and the patient via fluid paths 17A and 17B. According to various embodiments, the first fluid path 17A and the second fluid path 17B may converge at a fluid mixing connector providing turbulent mixing of the first and second fluids, such as the fluid mixing connectors described in International PCT Applications No. PCT / US2021 / 019507 and PCT / US2014 / 026324, the disclosures of which are incorporated herein by reference.

[0202] Now for reference Figure 4 The present disclosure illustrates schematic diagrams of example components of an embodiment of a controller 200 for implementing and performing the systems and methods described herein. In some embodiments, the controller 200 may include components that are more complex than... Figure 4 The diagram shows more components, fewer components, different components, or components arranged differently. The controller 200 may include a bus 202, at least one processor 204, a memory 206, a storage unit 208, and an input unit 210 (e.g., ...). Figure 3The diagram shows a GUI, keyboard, or other user interface 11, an output component 212 (e.g., a GUI or other user interface 11), and a communication interface 214 (e.g., a GUI or other user interface 11). Bus 202 may include components that allow communication between components of controller 200. In some non-limiting embodiments, at least one processor 204 may be implemented in hardware, firmware, or a combination of hardware and software. For example, at least one processor 204 may include a processor (e.g., a central processing unit (CPU), graphics processing unit (GPU), accelerated processing unit (APU), etc.), a microprocessor, a digital signal processor (DSP), and / or any processing component that can be programmed to perform functions (e.g., a field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), etc.). Memory 206 may include random access memory (RAM), read-only memory (ROM), and / or another type of dynamic or static memory device (e.g., flash memory, magnetic storage, optical storage, etc.) that stores information and / or instructions used by at least one processor 204.

[0203] Storage component 208 may store information and / or software related to the operation and use of controller 200. For example, storage component 208 may include a hard disk and / or another type of computer-readable medium. Input component 210 may include components that allow controller 200 to receive information, for example, via user input (e.g., GUI, touchscreen display, keyboard, keypad, mouse, buttons, switches, microphone, etc.). Additionally or alternatively, input component 210 may include sensors for sensing information (e.g., Global Positioning System (GPS) components, accelerometers, gyroscopes, actuators, etc.). Output component 212 may include components that provide output information from controller 200 (e.g., GUI, display, speaker, one or more light-emitting diodes (LEDs), etc.). Communication interface 214 may include transceiver-like components (e.g., transceiver, separate receiver and transmitter, etc.) that enable controller 200 to communicate with other devices, for example, via a wired connection, a wireless connection, or a combination of wired and wireless connections. Communication interface 214 may allow controller 200 to receive information from another device and / or provide information to another device. Input component 210, output component 212 and / or communication interface 214 may correspond to user interface 11 (see...) Figure 3 (or a component of the user interface 11.)

[0204] The controller 200 can execute the methods described herein based on software instructions stored in a computer-readable medium, such as memory 206 and / or storage unit 208, executed by at least one processor 204. The computer-readable medium can include any non-transitory memory device. Memory devices include memory space located within a single physical storage device or memory space distributed across multiple physical storage devices. The software instructions can be read into memory 206 and / or storage unit 208 via communication interface 214 from another computer-readable medium or from another device. When executed, the software instructions stored in memory 206 and / or storage unit 208 can cause the processor 204 to perform one or more processes described herein. Additionally or alternatively, hardwired circuitry can be used in place of or in conjunction with the software instructions to perform one or more processes described herein.

[0205] The overall structure and function of injectors 10 and 100 have been described. The following will refer to... Figures 5A-5B A more detailed discussion of the construction used with Figures 1-2 Injector 10 or Figure 3 A non-limiting embodiment of a syringe 300 used in conjunction with an injector 100. The syringe 300 typically has a cylindrical syringe barrel 318 formed of glass, metal, or a suitable medical-grade plastic. The syringe 318 has a proximal end 320 and a distal end 324, wherein sidewalls 319 (as shown in the image) are... Figure 5B (As shown) The nozzle 322 extends between the proximal end 320 and the distal end 324 along the length of the syringe's longitudinal axis 315, which extends through the center of the barrel 318. The barrel 318 may be made of a transparent or translucent material. The nozzle 322 extends from the distal end 324 of the barrel 318. Figure 5B As shown, the cylinder 318 has an outer surface 321 and an inner surface 323, the inner surface 323 defining an internal volume 325 for containing fluid therein. The proximal end 320 of the cylinder 318 can be sealed with a plunger 326 slidably passing through the cylinder 318. When the plunger 326 is advanced through the cylinder 318, the plunger 326 forms a liquid-tight seal against the inner surface 323 of the sidewall 319 of the cylinder 318. According to various engagement mechanisms as described herein, the plunger 326 is configured to releasably engage the piston of the fluid injectors 10, 100.

[0206] The drip flange 335 extends radially outward from the outer surface 321 of the syringe barrel 318 and prevents fluid dripping from the nozzle 322 from entering the syringe port on the injector. In some embodiments, the drip flange 335 defines a stop surface that defines the insertion portion 330 of the syringe 300.

[0207] refer to Figure 5A In some embodiments, the proximal end 320 of the syringe 300 is sized to be removably inserted into the syringe port of the injector 10, 100 (e.g., Figure 1 and3 (As shown) or a pressure sheath (not shown) that engages with a fluid injector. The proximal end 320 of the syringe 300 may define an insertion portion 330 that is removably inserted. Figure 1 The injector 10 shown or Figure 3 The syringe port of the injector 100 is shown, while the remainder of the syringe 300 remains outside the syringe port. In other embodiments, the syringe 300 may be inserted into a hole in a pressure sheath and releasably retained in the pressure sheath by one or more retaining features, such as those described in PCT International Application No. PCT / US2020 / 049885, the disclosure of which is incorporated herein by reference. In some embodiments, the proximal end 320 of the syringe 300 includes one or more syringe retaining members 331 adapted to form a locking engagement with a corresponding locking mechanism in the syringe port of the injector 10, 100 for releasably retaining the syringe 300 in the syringe port. Suitable non-limiting constructions for releasably locking the syringe 300 to the injector 10, 100 are described in U.S. Patent Nos. 9,173,995 and 9,199,033, the disclosures of which are incorporated herein by reference in their entirety. For clarity, the syringe 300 has been omitted from many of the figures of the corresponding plunger engagement mechanism of this disclosure.

[0208] refer to Figures 6-8C According to one embodiment of this disclosure, a plunger 326 is shown. The plunger 326 includes a plunger body 332 defining a longitudinal axis 334 and having a proximal end 336, a distal end 338, and a circumferential sidewall 339 connecting the proximal end 336 and the distal end 338. The sidewall 339 may have a uniform or non-uniform thickness between the proximal end 336 and the distal end 338. At least a portion of the sidewall 339 may be conical. The plunger body 332 may be formed of glass, metal, or a suitable medical-grade plastic.

[0209] The plunger body 332 has an inner cavity 340 ( Figure 7The plunger body 332 has a conical portion 342 at its distal end 338 and a cylindrical portion 344 at its proximal end 336. The conical portion 342 may be integrally formed with the cylindrical portion 344. In some embodiments, the conical portion 342 may be attached to the cylindrical portion 344 of the plunger body 332 using, for example, friction fit and / or adhesive, welding, or by molding or other means. The conical portion 342 may have a truncated end 346 with a molded protrusion 348 configured to engage with a sensing member, as described herein. In some embodiments, the distal end 338 of the plunger body 332 may be open or closed. In some embodiments, the cylindrical portion 344 may have a boss 345 projecting radially outward relative to the longitudinal axis 334. In this way, the boss 345 divides the cylindrical portion 344 into a first portion 347a having a first inner diameter and a second portion 347b having a second inner diameter greater than the first inner diameter.

[0210] refer to Figure 7 The plunger 326 may have one or more release tabs 380 projecting from the inner surface 352 of the cavity 340 of the plunger body 332. In some embodiments, the one or more release tabs 380 may project radially inward from the inner surface 352 of at least a portion (e.g., a first portion 347a) of the cylindrical portion 344 of the plunger body 332. The one or more release tabs 380 may be configured to interact with at least a portion of a plunger engagement mechanism on the piston to release the plunger 326 from the piston, for example, by rotation of the syringe 300, as the plunger 326 rotates about its longitudinal axis 334. In some embodiments, a plurality of release tabs 380 may be radially separated relative to the longitudinal axis 334 of the plunger along the circumference of the inner surface 352 of the cavity 340. In such embodiments, the release tabs 380 are separated from each other by portions of the inner surface 352 of the cavity 340. In embodiments providing more than two release tabs 380, the release tabs 380 may be evenly spaced from each other. In some embodiments, the release tabs 380 may have unequal angular extensions and / or unequal angular spacings between retaining ribs 350 surrounding the inner surface 352 of the inner cavity 340. The proximal end 382 of each release tab 380 may have a sharp or angled guide surface 384 configured to orient the plunger 326 relative to at least a portion of the plunger engagement mechanism, as described in some embodiments herein.

[0211] refer to Figure 6 The plunger 326 may have a plunger cap 357 with a resilient seal 358 covering at least a portion of the outer surface 360 ​​of the plunger body 332. The seal 358 may be a flexible seal that engages the inner surface 323 of the syringe barrel 318. Figure 5BAs shown in the diagram, the seal 358 liquid-tightly seals the internal volume 325 of the syringe barrel 318. The seal 358 may be separate from the plunger body 332, or it may be integrally formed with the plunger body 332, for example, by co-molding. In some embodiments, the outer surface 360 ​​of the plunger body 332 may have a circumferential groove 362. At least a portion of the seal 358 may be retained within the circumferential groove 362. The outer surface 364 of the seal 358 may have one or more lips, protrusions, or other sealing elements 366 that slidably engage the inner surface of the syringe barrel 318. In some embodiments, at least the sealing element 366 of the seal 358 may be made of an elastomeric material that elastically engages with the inner surface 323 of the syringe barrel 18. At least one extension 356 on the plunger body 332 may prevent the seal 358 from disaligning axially with the syringe 300 as the plunger 326 moves through the syringe barrel 318.

[0212] refer to Figure 7 The plunger 326 may have at least one resiliently deflectable retaining member 368 (hereinafter referred to as "retaining member 368") projecting proximally from the plunger body 332. In some embodiments, at least one retaining member 368 may project proximally from an inner surface 352 of a cavity 340 of the plunger body 332. At least one retaining member 368 has a first distal end 370 connected to the plunger body 332 and a second proximal end 372 radially deflectable relative to the first end 370 in a direction toward and / or away from the longitudinal axis 334. As described herein, when at least one retaining member 368 engages the injector 10, 100 ( Figure 1 and Figure 3When at least a portion of the plunger engagement mechanism on the piston of the piston 326 is engaged, the second end 372 may be radially deflected relative to the first end 370. That is, as a portion of the plunger engagement mechanism moves in a distal direction and contacts the retaining member 368, the portion of the plunger engagement mechanism causes the retaining member 368 to be radially deflected. Similarly, during the disengagement operation of the piston from the plunger, as a portion of the plunger engagement mechanism moves in a proximal direction and contacts the retaining member 368, the portion of the plunger engagement mechanism causes the retaining member 368 to be radially deflected. The first end 370 and the second end 372 may be spaced apart in a direction extending substantially along the direction of the plunger longitudinal axis 334 of the plunger 326. At least one retaining member 368 may be linearly or curvilinearly abutted between the first end 370 and the second end 372. In some embodiments, one or more retaining members 368 may extend in a direction parallel to the direction of the plunger longitudinal axis 334. In other embodiments, one or more retaining members 368 may extend in a direction angled relative to the direction of the plunger longitudinal axis 334. For example, one or more retaining members 368 may be angled toward or away from the longitudinal axis 334 of the plunger in a direction extending from the proximal end 336 of the plunger body 332 to the distal end 338 of the plunger body 332.

[0213] In some embodiments, a plurality of retaining members 368 are radially spaced apart from the longitudinal axis 334 of the plunger along the circumferential direction of the inner surface 352 of the inner cavity 340. In such embodiments, the retaining members 368 are separated from each other by portions of the inner surface 352 of the inner cavity 340. In embodiments providing more than two retaining members 368, the retaining members 368 may be evenly spaced apart from each other. In an exemplary and non-limiting aspect, six retaining members 368 have equal angular spacing, for example, as shown in the figure. Figures 7-8C As shown, each retaining member 368 is spaced 60 degrees from the retaining member 368 adjacent on either side. In some embodiments, the retaining members 368 may have unequal angular extensions and / or unequal angular spacings between the retaining members 68 surrounding the inner surface 352 of the inner cavity 340. The radial spacing of at least one retaining member 368 relative to the longitudinal axis 334 of the plunger is selected to correspond to the outer circumferential direction of the piston, as described herein.

[0214] The second end 372 of the retaining member 368 has at least one latch 374. The at least one latch 374 projects radially from the retaining member 368. The at least one latch 374 is configured to interact with a portion of the plunger engagement mechanism to deflect the second end 372 as the portion of the plunger engagement mechanism passes the at least one latch 372. In some embodiments, the at least one latch 374 may project radially inward toward the plunger longitudinal axis 334 of the plunger body 332. In this way, the at least one retaining member 368 is configured to deflect in a radially outward direction due to contact between the latch 374 and at least a portion of the plunger engagement mechanism on the piston, as described herein. In some embodiments, the at least one latch 374 may project radially outward away from the plunger longitudinal axis 334 of the plunger body 332. In this way, the at least one retaining member 368 is configured to deflect in a radially inward direction due to contact between the latch 374 and at least a portion of the plunger engagement mechanism on the piston, as described herein. The at least one retaining member 368 is configured to return to its undeflected state by moving in a radially inward direction.

[0215] At least one snap-fit ​​374 may be integrally formed with the second end 372 of at least one retaining member 368, or it may be fastened to the second end 372 of at least one retaining member 368 by, for example, friction fit and / or adhesive, welding, or by co-molding or other means. In other embodiments, at least one snap-fit ​​374 may be formed on the second end 372 of at least one retaining member 368 by etching, laser cutting, or machining. As described herein, at least one snap-fit ​​374 is shaped to be received within a snap-fit ​​receiving space or groove of a plunger engagement mechanism disposed on the piston of the injector 10, 100, to lock at least one retaining member 368 relative to the piston when the plunger engagement mechanism is in a locked state or position. Figures 7-8C As shown, the latch 374 may have a distal surface 377 with a rounded edge. In some embodiments, the latch 374 may have a proximal surface 379 with a rounded edge. The shapes of the distal surface 377 and the proximal surface 379 allow the latch 374 itself to not form a locking engagement with the corresponding locking feature on the plunger engagement mechanism on the piston. Instead, the latch 374 must act in conjunction with the actuation of the plunger engagement mechanism to form a locking engagement with the piston.

[0216] refer to Figures 8A-8C The plunger 326 is shown according to various embodiments of the present disclosure. Figures 8A-8C The components of plunger 326 shown are substantially similar to or equivalent to those described herein. Figures 6-7 The plunger 326 is a component of that plunger. Therefore, Figures 8A-8C The reference markers in the text are used to show Figures 6-7The same parts corresponding to the reference numerals are discussed here, and only the relative differences between embodiments of plunger 326 are discussed here.

[0217] refer to Figures 8A-8C The plunger 326 may have one or more release tabs 380 protruding from the inner surface 352 of at least a portion (e.g., the second portion 347b) of the cylindrical portion 344 of the plunger body 332. The one or more release tabs 380 may project axially from the boss 345 and radially inwardly from the inner surface 352 of the second portion 347b of the cylindrical portion 344, and may extend along the entire width of the boss 345. Figure 8A Or along a portion of the width of boss 345 ( Figure 8B and 8C The second part 347b protrudes radially inward from its inner surface 352. As described herein, one or more release tabs 380 are configured to interact with at least a portion of the plunger engagement mechanism on the piston to release the plunger 326 from the piston as the plunger 326 rotates about its longitudinal axis 334, for example, due to the rotation of the syringe 300.

[0218] Figure 8C An embodiment of the central plunger 326 has at least one retaining member 368 with a latch 374, the latch 374 protruding radially outward in a direction away from the longitudinal axis 334 of the plunger. In this way, Figure 8C At least one retaining member 368 shown is configured to deflect in a radially inward direction due to contact between the snap 374 and at least a portion of the plunger engagement mechanism on the piston, as described herein. Figure 8C At least one retaining member 368 shown is configured to return to its undeflected state by moving in a radially outward direction.

[0219] refer to Figure 9 An embodiment of a piston 400 separate from the injector is shown. In other embodiments, the piston 400 may be configured for use with a fluid injector such as that described herein or with any fluid injector configured for medical use. The piston 400 is configured to reciprocate within the housing of the syringe via a drive mechanism. The drive mechanism may include, for example, a motor 402 (such as...). Figure 2 (As shown), hydraulic system, pneumatic system, or any combination thereof. Controller 200 ( Figure 2 The controller 200 can be configured to control the operation of the drive mechanism, thereby controlling the reciprocating movement of the piston 400. In some embodiments, the controller 200 may be configured to control the engagement and / or disengagement of the piston 400 from the plunger.

[0220] Continue to refer to Figure 9The piston 400 has a body 404 and a piston head 406 at the distal end of the body 404. The piston head 406 is configured to be removably connected to a plunger of a syringe, for example... Figure 8C The plunger 326 is shown. The piston head 406 extends radially outward beyond the radial edge of the body 404. The piston 400 is constructed of a relatively rigid material resistant to deformation, such as metal, plastic, or a combination thereof. The piston head 406 has a generally cylindrical structure, with its distal end configured to be received within the internal cavity 340 of the plunger 326. Figure 8C At least a portion of the piston head 406 may be made of a transparent or translucent material configured to allow electromagnetic radiation emitted by one or more electromagnetic radiation sources in the piston 400 to pass through, illuminating at least a portion of the plunger 326 and / or the syringe 300.

[0221] In some embodiments, a sensing element, such as a spring-loaded pin connected to the sensor (see, for example...), may be provided. Figures 21A-21B (Pin 767 in the piston). A sensing member may extend along the longitudinal axis of piston 400 and may protrude through at least a portion of piston head 406. The sensing member is operable to sense contact with a surface (e.g., surface 348 of plunger 326) and control movement of piston 400 based on the sensed condition. For example, initial contact between the sensing member and surface 348 of plunger 326 may cause the pin to retract proximally, thereby contacting the sensor. The sensor may be connected to a drive mechanism of piston 400 such that when the sensor is activated by the pin, the sensor controls movement of the drive mechanism. For example, the drive mechanism may stop or slow down from a first rate to a second, slower rate.

[0222] In some embodiments, the piston head 406 has a plunger engagement mechanism 412 configured to releasably engage the plunger 326 to facilitate reciprocating drive of the plunger 326 within the barrel of the syringe 300. Figures 5A-5B (Continue to refer to...) Figure 9The plunger engagement mechanism 412 has a plunger engagement sleeve 414 and a plunger engagement pin 418. The plunger engagement sleeve 414 has a central opening 416, and the plunger engagement pin 418 is reciprocating within the central opening 416 of the plunger engagement sleeve 414 along the direction of the longitudinal piston axis 420. The plunger engagement pin 418 is reciprocated by an actuator 422. The plunger engagement mechanism 412 is operable between an engaged position or state and a disengaged position or state. In the engaged position or state, the plunger engagement pin 418 is positioned within the plunger engagement sleeve 414 to capture at least one retaining member 368 associated with the plunger 326 in a receiving space 415 between the plunger engagement sleeve 414 and the plunger engagement pin. Conversely, in the disengaged position or state, the plunger engagement post 418 may be positioned relative to the plunger engagement sleeve 414 to allow removal from the receiving space 415 between the plunger engagement sleeve 414 and the plunger engagement post 418 of at least one retaining member 368 associated with the plunger 400. Figure 9 The portions of the plunger engagement mechanism 412 are shown in both the engaged and disengaged positions or states. Specifically, Figure 9 The plunger engagement pin 418 is shown in both its engaged position or state (right side of the cross-section) and its disengaged position or state (left side of the cross-section). During the movement of the plunger engagement mechanism 412 from the engaged position or state to the disengaged position or state, the plunger engagement sleeve 414 and / or the plunger engagement pin 418 may move linearly and / or rotatably relative to the piston 400.

[0223] refer to Figures 10A-10B The plunger engagement sleeve 414 has a hollow body 424, wherein at least a portion of the outer surface of the hollow body 424 defines at least a portion of the piston head 406 (e.g., Figure 9 (As shown). The distal portion or distal end 426 of the plunger engagement sleeve 414 is formed to be received within the internal cavity 340 of the plunger 326, while at least a portion of the plunger 326 (e.g., at least one retaining member 368) is configured to be received within the central opening 416 (see, for example). Figure 9 The central opening 416 extends through the hollow body 424 of the plunger engagement sleeve 414.

[0224] refer to Figure 10BThe inner surface 428 of the central opening 416 may have a bevel 430 at a portion of the distal end of the opening 416, such that the inner diameter of the opening 416 narrows in the direction from the distal end 426 of the hollow body 424 toward the proximal portion or proximal end 432. The bevel 430 may be configured to engage with a snap 374 during the connection of the plunger 326 to the distal portion or distal end 426 of the plunger engagement sleeve 414 and deflect at least one retaining member 426 associated with the plunger 326 in a radially inward direction. The bevel 430 may terminate at a locking rib 434. At least one snap 374 may be bent and abut against the proximal surface of the locking rib 434 in such a way that if the piston moves in a proximal direction, at least one snap 374 may be easily bent and moved past the locking rib 434 unless the plunger engagement mechanism 412 moves into a locking engagement configuration. That is, if the piston is in a disengaged configuration, at least one retaining member 426 and the corresponding snap 374 can be easily bent and moved into and out of the central opening 416 of the plunger engagement sleeve 414. In some embodiments, a locking rib 434 extends continuously or discontinuously around the inner surface 428 of the hollow body 424 of the plunger engagement sleeve 414 and defines the surface of at least one snap 374 on at least one retaining member 368 on the engaging plunger to prevent the plunger 326 from being removed from the piston 400 when the plunger 326 is locked engaged with the plunger engagement mechanism 412, as described herein. The inner surface 426 of the central opening 416 may be substantially cylindrical on the proximal side of the locking rib 434.

[0225] The proximal portion or proximal end 432 of the hollow body 424 is integrally formed with the distal portion or distal end 426, and its inner surface 436 has a longitudinal groove 438, the longitudinal groove 438 being configured to receive the guide pin 439 of the plunger engagement post 418. Figure 9 The longitudinal groove 438 has a distal stop 440 for defining distal movement of the guide pin 439, and thereby defining distal movement of the plunger engagement pin 418 relative to the plunger engagement sleeve 414. The outer surface 442 of the proximal portion or proximal end 432 of the hollow body 424 may have a toothed portion 444 configured to interact with one or more release tabs 380 on the plunger 326 during removal from the plunger engagement mechanism 412.

[0226] refer to Figures 11A-11B The plunger engagement mechanism 412 also includes a housing 446 configured to accommodate the actuator 422. For example... Figure 11BAs shown, the housing 446 may have a cylindrical structure with a connecting member 448 configured to connect to a connector 450 on the actuator 422. In some embodiments, the connecting member 448 on the housing 446 may be an internally threaded surface configured to thread-engage the externally threaded connector 450 on the actuator 422. In other embodiments, the connecting member 448 may be an adhesive, clip, interference fit, fastener, or any other connection feature for removably or non-removably connecting the housing 446 to the connector 450 on the actuator 422.

[0227] refer to Figures 11A-11B As shown, the housing 446 has a proximal portion 452 connected to the distal portion 454. In some embodiments, the distal portion 454 may have a smaller outer diameter than the proximal portion 452, such that a boss 456 is defined at the transition between the proximal portion 452 and the distal portion 454. In some embodiments, the boss 456 may be configured to support the proximal end of a biasing member 496 configured to engage with the piston engagement mechanism 412 during disengagement of the plunger 326 from the piston 400. Figure 9 Release plunger 326.

[0228] A plunger release sleeve 458 surrounds the distal portion 454 of a housing 446. In some embodiments, the plunger release sleeve 458 has a cylindrical sidewall 460 having an opening 462 extending therethrough. The opening 462 may have a longitudinal surface 463 substantially parallel to the longitudinal axis 464 of the plunger release sleeve 458, and an inclined surface 466 adjacent to the longitudinal surface 463 and inclined downward relative to the longitudinal axis 464 of the plunger release sleeve 458 in a direction from the distal end 468 toward the proximal end 470. As described herein, the longitudinal surface 463 is configured to guide the guide pin 439 of the plunger engagement pin 418 during movement of the plunger engagement pin 418 in the longitudinal direction along the longitudinal axis 420 of the piston 400. Figure 9 Meanwhile, the inclined surface 464 is configured to guide the guide pin 439 during the rotational movement of the plunger 326 relative to the piston 400 (e.g., during the removal of the plunger 326 from the piston 400). One or more lamps 472 may be disposed on a printed circuit board 474 connected to the distal end 468 of the plunger release sleeve 458. As described herein, one or more lamps 472 may be configured to illuminate at least a portion of the plunger 326.

[0229] refer to Figure 11BActuator 422 may be configured to have an engaged state for moving one of the plunger engagement sleeve 414 and plunger engagement post 418 to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and plunger engagement post to a disengaged position. In some embodiments, actuator 422 may automatically move to the disengaged state, for example, during de-energization of actuator 422. In some embodiments, actuator 422 may be in the engaged state only during proximal movement of piston 400. In some embodiments, actuator 422 may be a solenoid configured to be primarily in the disengaged state and may be in the engaged state only during plunger 326 connection to piston 400. In other embodiments, actuator 422 may be a rotary motor, a linear motor, or a linear actuator. In some embodiments, actuator 422 is a linear actuator that can be manually reversed in the event of injector de-energization.

[0230] refer to Figure 9 The plunger engagement sleeve 414 is rotatable about the longitudinal piston axis 420 relative to the housing 446 and the plunger release sleeve 458 between a first position and a second position. In some embodiments, the plunger engagement sleeve 414 can rotate in a clockwise and counterclockwise direction, or in one of a clockwise and counterclockwise direction. The plunger engagement sleeve 414 can rotate from the first position to the second position due to the rotational movement of the plunger 326 about the longitudinal piston axis 420. For example, the plunger engagement sleeve 414 can rotate about the longitudinal axis 420 due to the interaction between the release tab 390 on the plunger 326 and the toothed portion 444 on the piston engagement sleeve 414. In some embodiments, rotation of the plunger engagement sleeve 414 can move the guide pin 439 along the inclined surface 466 of the plunger release sleeve 458 to move the plunger engagement pin 418 to a disengaged or engaged position. A biasing member 496 may be provided to bias the plunger engagement sleeve 414 to the first position. In this way, as the plunger engagement sleeve 414 rotates from the first position toward the second position, the biasing member 496 builds up potential energy therein, which is then used to help the plunger engagement sleeve 414 return toward the first position. In some embodiments, the biasing member 496 may be a torsion spring, with one end connected to the plunger engagement sleeve 414 and the other end connected to the housing 446 or the plunger release sleeve 458.

[0231] refer to Figure 12The plunger engagement post 418 is shown separate from the plunger engagement mechanism 412. The plunger engagement post 418 has a shaft 472 with a proximal end 474 and a distal end 476. The distal end 476 of the shaft 472 has a tapered end face 478 configured to contact at least one flexible retaining member 368 on the plunger 326 when the plunger engagement post 418 is in the engaged position, to lock at least one snap 374 onto a locking rib 434 of the plunger engagement sleeve 414, thereby preventing the plunger 326 from being removed from the piston 400. A seal 480 may be provided at the distal end 478 for sealing the inner surface 428 of the plunger engagement sleeve 414 (e.g., ...). Figures 10A-10B (As shown). Seal 480 can be an O-ring seal.

[0232] The plunger engagement post 418 also includes a guide pin 439 configured to guide movement of the plunger engagement post 418 relative to the plunger engagement sleeve 412. In some embodiments, the guide pin 439 extends through the shaft 472 and is arranged substantially perpendicular to the longitudinal axis 482 of the shaft 472. A restoring resilient member 484 surrounds the shaft 472 and has a distal end 486 of a boss 488 adjacent to the distal end 478 of the shaft 472. The proximal end 490 of the restoring resilient member 484 may be configured to contact the actuator 422 or the housing 446. The restoring resilient member 484 may be a compression spring configured to bias the plunger engagement post 418 in a distal direction toward the engagement position, as described herein. In other embodiments, the restoring resilient member 484 may be a tension spring configured to bias the plunger engagement post 418 in a proximal direction toward the disengagement position.

[0233] The structure of the plunger 326 and piston 400 has been described according to a non-limiting embodiment of this disclosure, and will now be referred to... Figures 13A-13J Describe the method of engaging and disengaging the plunger 326 and the piston 400.

[0234] Figure 13A The piston 400 is shown before connection to the plunger 326, with its plunger engagement mechanism 412 in an engaged position or state. In some embodiments, the default state of the plunger engagement mechanism 412 may be the engaged position or state. To connect the plunger 326 to the piston 400, the syringe 300 is first connected to the injectors 10, 100 (…). Figure 1 and 3 During the connection of syringe 300 to injectors 10, 100, piston 400 retracts into the housing of injectors 10, 100. After connecting syringe 300 to injectors 10, 100, piston 400 can be advanced in a direction toward the distal side of plunger 326.

[0235] refer to Figure 13BActuator 422 is energized to retract shaft 472 of plunger engagement post 418 from the engaged position or state to the disengaged position or state in the proximal direction indicated by arrow A. The proximal movement of shaft 472 opens receiving space 415 between plunger engagement sleeve 414 and plunger engagement post 418 to allow insertion into or removal from receiving space 415 of plunger 326 or one or more retaining members 368. This movement also compresses restoring elastic member 484 between boss 488 on the distal end of shaft 472 and actuator 422. The compression of restoring elastic member 484 establishes potential energy therein, which, upon release, can be used to guide plunger engagement post 418 toward the engaged position or state.

[0236] In other embodiments, actuator 422 can be de-energized, and shaft 472 of plunger engagement post 418 can retract from the engaged position or state to the disengaged position or state in the proximal direction indicated by arrow A, due to the elastic restoring force of restoring member 484. In such an embodiment, restoring member 484 may be a tension spring that is stretched from a first state to a second state due to actuation of actuator 422. Once actuator 422 is de-energized, the restoring force in restoring member 484 pushes plunger engagement post 418 to the disengaged position or state. In this way, plunger engagement post 418 is in the normal disengaged position or state, which allows plunger 326 to be removed from piston 400 in the event that actuator 422 is inoperable (e.g., due to de-energization).

[0237] refer to Figure 13C The piston 400 can move axially in a direction toward the distal side of the plunger 326 (as indicated by arrow B). In some embodiments, a controller 200 can be used. Figure 2 The drive mechanism 402, operated by the piston, propels the piston 400 distally. In other embodiments, the piston can be moved distally manually.

[0238] refer to Figure 13D The piston 400 is axially advanced distally, causing at least one retaining member 368 of the plunger 326 to be received within the central opening 416 of the plunger engagement sleeve 414. Initially, the inner surface 428 of the central opening 416 contacts the snap 374 of the at least one retaining member 368. Because the snap 374 projects radially outward relative to the at least one retaining member 368, it is positioned at a greater radial distance from the longitudinal axis 334 of the plunger than the ramp 430 of the central opening 416. In this way, continued distal movement of the piston 400 causes at least one retaining member 368 to deflect radially inward due to the contact between the snap 374 and the ramp 430. In embodiments with multiple retaining members 368, each retaining member 368 deflects radially inward.

[0239] During sustained axial movement of the piston 400 in a distal direction, the latch 374 deflects on the locking rib 434 of the piston engagement sleeve 414. After the latch 374 is positioned proximally relative to the locking rib 434, distal movement of the piston 400 relative to the plunger 326 ceases, or contact between the distal portion or distal end 426 of the plunger engagement sleeve 414 and the inner surface 352 of the inner cavity 340 of the plunger body 332 causes the plunger 326 to move distally together with the piston 400, and at least one retaining member 368 can be resiliently deflected radially inward, such that the latch 374 is positioned proximally to the locking rib 434. In some embodiments, distal movement of the piston 400 relative to the plunger 326 may cease when a portion of the plunger engagement sleeve 414 engages with the drive shoulder 327 of the plunger 326. When at least one retaining member 368 is in Figure 13D In the indicated position, plunger 326 is not locked into engagement with piston 400 because at least one retaining member 368 can deflect radially inward as piston 400 moves proximally or plunger 326 moves distally (e.g., due to removal of the syringe from the injector). As plunger 326 engages piston 400, one or more release tabs 380 on plunger 326 align with toothed portions 444 on the outer surface 442 of plunger engagement sleeve 414. In some embodiments, plunger 326 may not be in the engaged locked position with piston 400 as piston 400 moves distally and only moves to the engaged locked position during proximal movement of piston 400. This feature allows for easy removal of syringe 300 and plunger 326 after a short distal movement of piston 400 and can reduce wear on system components and / or motors by requiring only locking engagement when piston 400 is retracted.

[0240] refer to Figure 13E When actuator 422 is de-energized, it allows the shaft 472 of plunger engagement post 418 to move from a disengaged position or state to an engaged position or state in the distal direction indicated by arrow C. In other embodiments, actuator 422 may be energized to move the shaft 472 of plunger engagement post 418 in the distal direction.

[0241] Movement of shaft 472 in the distal direction closes the receiving space 415 between plunger engagement sleeve 414 and plunger engagement post 418, thereby locking at least one latch 374 onto locking rib 434 to prevent one or more retaining members 368 of plunger 326 from being removed from the receiving space 415, thus preventing plunger 326 from being removed from piston 400. Due to the release of potential energy stored in restoring elastic member 484, plunger engagement post 418 moves from a disengaged position or state to an engaged position or state. In other embodiments, plunger engagement post 418 moves from a disengaged position or state to an engaged position or state due to actuation of actuator 422, which establishes potential energy in restoring elastic member 484. Once plunger engagement post 418 has moved to the engaged position or state, at least one retaining member 368 of plunger 326 is captured between plunger engagement sleeve 414 and plunger engagement post 418, such that axial movement of piston 400 causes corresponding axial movement of plunger 326 within syringe barrel. The piston 400 and the connected plunger 326 can then reciprocate within the barrel 318 of the syringe 300. Figures 5A-5B In a particular embodiment, the piston 400 and the connected plunger 326 can move proximally within the cylinder 318, and the piston 400 can move distally when it is in an engaged or disengaged position from the plunger 326. In some embodiments, the piston 400 can be controlled by a controller 200. Figure 2 The drive mechanism 402 is advanced distally to deliver fluid from the syringe 300 or proximally to fill the syringe 300 with fluid.

[0242] In some embodiments involving manual disengagement of the syringe, in order to unlock the syringe 300 from the syringe port of the injector and disengage the plunger 326 from the piston 400, the syringe 300 can be rotated clockwise or counterclockwise relative to the syringe port about the longitudinal axis of the syringe. Because the plunger 326 is substantially stationary due to frictional interaction against the syringe barrel 318, rotation of the syringe 300 also causes the plunger 326 to rotate relative to the piston 400 about the longitudinal piston axis 420. Rotation of the plunger 326 also causes the plunger engagement sleeve 414 to rotate from a first position to a second position relative to the plunger release sleeve 458 of the plunger engagement mechanism 412, as one or more release tabs 380 on the plunger 326 align with the toothed portion 444 on the outer surface 442 of the plunger engagement sleeve 414. Because the guide pin 439 on the plunger engagement post 418 is received within the longitudinal groove 438 of the plunger engagement sleeve 414, the plunger engagement post 418 also rotates with the rotation of the plunger engagement sleeve 414. Rotation of the plunger engagement pin 418 causes the guide pin 439 to be guided along the inclined surface 466 of the plunger release sleeve 458 (see...). Figure 13FFurthermore, the compression of the restoring elastic member 484. In addition, the rotation of the plunger engagement sleeve 414 about the longitudinal piston axis 420 establishes potential energy in the biasing member 496.

[0243] In other embodiments, such as when the syringe is contained within a pressure sheath, rotating the syringe and plunger to disengage the plunger 326 from the piston 400 may not be possible. According to these embodiments, disengagement and engagement of the piston 400 from the plunger 326 can be achieved electromechanically, for example, by using a motorized or electric actuator to disengage the plunger 326 from the piston 400. As described herein, an electric motor (e.g., a linear motor or rotary electric motor) or an electric actuator (e.g., a solenoid) can be used to move the plunger engagement post 418 between an engaged position and a disengaged position to engage and disengage the plunger 326 from the piston 400. When the plunger 326 is in the disengaged position, for example at the end of the injection process, the syringe 300 can be removed from the injector, and the injector can be prepared for the next process.

[0244] refer to Figure 13G Movement of the guide pin 439 along the inclined surface 466 of the plunger release sleeve 458 causes the plunger engagement pin 418 to move axially from the engaged position or state to the disengaged position or state in the proximal direction of arrow D. In some embodiments, the piston engagement pin 418 can be moved proximally by energizing the actuator 422 to retract the shaft 472 of the plunger engagement pin 418. In this way, the plunger engagement pin 418 can be moved manually, for example by rotation of the plunger 326 relative to the piston 400, or by actuation of the actuator 422. Thus, in the event of a power failure, the plunger 326 can be removed from the piston 400. Proximal movement of the plunger engagement pin 418 opens a receiving space 415 between the plunger engagement sleeve 414 and the plunger engagement pin 418 to allow removal of one or more retaining members 368 of the plunger 326 from the receiving space 415. Furthermore, this configuration, which requires only the actuation of actuator 422 for engagement, can reduce wear on system components and / or motors by requiring only locking engagement when piston 400 moves in the proximal direction.

[0245] With the plunger engagement mechanism 412 in the disengaged position or state, the syringe 300 can be pulled distally or the piston 400 can be retracted proximally to remove the plunger 326 from the piston 400 and remove the syringe 300 and plunger 326 from the fluid injector. During this relative movement of the piston 326 relative to the plunger 400 in a direction away from each other, the latch 374 deflects on the locking rib 434 of the piston engagement sleeve 414 to allow removal of one or more retaining members 368 from the piston. The plunger 326 can then be freely pulled away from the piston 400, as... Figure 13H As shown.

[0246] refer toFigures 13I-13J After the plunger 326 is removed from the piston 400, due to the restoring force provided by the biasing member 496, the plunger engagement sleeve 414 and the plunger engagement post 418 revolve around the longitudinal piston axis 420. Figure 9 (As shown) it automatically rotates from the second position to the first position. As the plunger engagement sleeve 414 and plunger engagement pin 418 move to the first position, the guide pin 429 is guided toward the distal end of the plunger release sleeve 458 along the inclined surface 466 of the plunger release sleeve 458 due to the restoring force provided by the restoring elastic member 484. This causes the plunger engagement pin 418 to move in the distal direction of arrow E. Figure 13J The position of the plunger engagement mechanism 412 in the middle and Figure 13A The position of the plunger engagement mechanism 412 is the same.

[0247] refer to Figures 14A-14C This shows a piston 500 and a plunger engagement mechanism 512 according to another embodiment of the present disclosure. Figures 9-13J The components of the piston 500 and plunger engagement mechanism 512 shown herein are the same as those referenced herein. Figures 14A-14C The components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Therefore, Figures 9-13J The reference marker in is used to indicate Figures 14A-14C The same parts corresponding to the reference marks, except Figures 9-13J The leading number in the reference marker used has changed from "4" to "5". For example, combined with Figures 14A-14C The piston described is indicated by the reference numeral "400", while Figures 9-13J The piston in the designation is marked with the reference numeral "500". This is because of the preceding information... Figures 14A-14C The discussion of the piston 400 and plunger engagement mechanism 412, which are roughly shown in the figure, applies to... Figures 9-13J The piston 500 and plunger engagement mechanism 512 are shown in the figure, so the following discussion will only focus on the relative differences between the components shown in these figures.

[0248] Figures 6-8B The piston 400 and plunger engagement mechanism 412 shown are configured to work with Figures 14A-14C The plunger 326 shown interacts, while Figure 8C The piston 500 and plunger engagement mechanism 512 are configured to work with Figures 6-8B The plunger 326 interacts. In this way, Figures 6-8B At least one retaining member 368 shown is configured to deflect in a radially outward direction due to contact between the snap 374 and at least a portion of the plunger engagement mechanism 518 on the piston, as described herein. Figure 14A At least one retaining member 368 shown is configured to return to its undeflected state by moving in a radially inward direction.

[0249] Continue to refer to Figure 15 The plunger engagement mechanism 512 has a plunger engagement sleeve 514 and a plunger engagement pin 518, the plunger engagement sleeve 514 having a central opening 516. The plunger engagement pin 518 has a proximal portion 519 rotatably connected to the plunger release sleeve 558, such that the plunger engagement pin 518 can rotate about a longitudinal piston axis 520. (Reference) Figures 9-13J The proximal portion 519 may have a toothed portion 544 at its distal end. (See references herein.) Figure 8A Like the toothed portion 444 of the described plunger engagement mechanism 412, the toothed portion 544 is configured to interact with the release tab 380 on the plunger 326. Figures 14A-14C , 8B (and 14A). The plunger engagement post 518 also has a post portion 521 extending distally from a proximal portion 519. In some embodiments, the proximal portion 519 and the post portion 521 may be integrally formed to constitute an integral part. One or more openings 523 may be formed in the plunger engagement post 518 by means of a connector 525 connecting the proximal portion 519 to the post portion 521. The openings 523 may be configured to receive a portion of the plunger engagement sleeve 514 passing through them. The upper surface of the connector 525 defines an engagement surface for contacting at least a portion of the plunger 326, such as the drive shoulder 327 of the plunger 326. The plunger engagement post 518 also has a longitudinal groove 538 configured to receive a guide pin 539. The longitudinal groove 538 has a distal stop 540 for defining distal movement of the guide pin 539, thereby defining distal movement of the plunger engagement sleeve 514 relative to the plunger engagement post 518.

[0250] Figure 9 The plunger engagement post 518 can rotate only about the piston's longitudinal axis 520. The plunger engagement post 518 can rotate between a first position and a second position about the longitudinal piston axis 520 and the plunger release sleeve 558. In some embodiments, the plunger engagement post 518 can rotate clockwise and counterclockwise, or one of clockwise and counterclockwise directions. The plunger engagement post 518 can rotate from the first position to the second position due to the rotational movement of the plunger 326 about the longitudinal piston axis 520. For example, the plunger engagement post 518 can rotate about the longitudinal axis 520 due to the interaction between the release tab 390 on the plunger 326 and the toothed portion 544 on the piston engagement post 518. Similar to... Figure 15The biasing member 496 shown has a biasing member (not shown) to bias the plunger engagement post 518 to a first position. In this way, as the plunger engagement post 518 rotates from the first position toward a second position, the biasing member builds up potential energy therein, which is then used to help the plunger engagement post 518 return to the first position. In some embodiments, the biasing member may be a torsion spring, with one end connected to the plunger engagement post 518 and the other end connected to the plunger release sleeve 558.

[0251] Continue to refer to Figure 14A The plunger engagement post 518 has a post portion 521 with a locking groove 527 that forms a latch 374 for receiving at least one flexible retaining member 368 of the plunger 326. The distal end of the post portion 521 may be shaped to deflect at least one retaining member 368 radially outward due to contact between the latch 374 and the outer surface of the post portion 521. In some embodiments, the distal end of the post portion 521 may include a bevel to further deflect at least one retaining member 368 radially outward. In this way, distal movement of the piston 500 relative to the plunger 326 causes at least one retaining member 368 to deflect radially outward due to contact between the latch 374 and the outer surface of the post portion 521. In embodiments with multiple retaining members 368, each retaining member 368 deflects radially outward.

[0252] Reference Figure 16 The plunger release sleeve 558 is at least partially housed within the hollow main structure of the plunger engagement sleeve 514 and the plunger engagement post 518. (Refer to...) Figure 14A The plunger release sleeve 558 has a cylindrical sidewall 560 with an opening 562 extending therethrough. The opening 562 may have a longitudinal surface 563 substantially parallel to the longitudinal axis 564 of the plunger release sleeve 558, and an inclined surface 566 adjacent to the longitudinal surface 563 and inclined downward relative to the longitudinal axis 564 of the plunger release sleeve 558 in a direction from the distal end 568 toward the proximal end 570. As described herein, the longitudinal surface 563 is configured to guide the guide pin 539 during movement of the plunger engagement sleeve 514 in the longitudinal direction along the longitudinal axis 520 of the piston 500. Figures 17A-17B The inclined surface 564 is configured to guide the guide pin 539 during the rotational movement of the plunger 326 relative to the piston 500 (and vice versa), for example, during the removal of the plunger 326 from the piston 500.

[0253] refer to Figure 15This illustrates a plunger engagement sleeve 514, separate from the rest of the plunger engagement mechanism 512. The plunger engagement sleeve 514 has a hollow body 524, at least a portion of which is configured to be received within a proximal portion 519 of the plunger engagement post 518. The distal portion or distal side 526 of the plunger engagement sleeve 514 is shaped to pass through the plunger engagement post 518 (…). Figures 14A-14B The opening 523 on the plunger 326 is received and positioned within the internal cavity 340 of the plunger 326. Figures 14A-14C At least a portion of the plunger 326, such as at least one retaining member 368, is configured to be received within a central opening 516 and within a receiving space 515 between the post portion 521 of the plunger engaging post 518 and the distal portion or distal end 526 of the plunger engaging sleeve 514. A portion of the inner surface 528 of the central opening 516 may have a chamfer 530 such that the inner diameter of the opening 516 narrows in a direction from the distal end 526 of the hollow body toward the proximal portion or proximal end 532. The chamfer 530 may be configured to deflect at least one retaining member 368 associated with the plunger 326 in a radially inward direction during the connection of the plunger 326 to the piston 500, and to create a tight-fitting interaction between the snap 374 of at least one flexible retaining member 368 and the locking groove 527 of the plunger engaging post 518.

[0254] Continue to refer to Figure 14B The hollow body 524 of the plunger engagement sleeve 514 has a through hole 533, which is configured to receive a guide pin 539 passing through it. The plunger engagement sleeve 514 is configured to rotate about its longitudinal axis 531 due to the rotation of the plunger 326 and the plunger engagement pin 518, and due to the engagement between the guide pin 539 and the inclined surface 566 of the plunger release sleeve 558.

[0255] The structure of the plunger 326 and piston 500 has been described according to a non-limiting embodiment of this disclosure, and will now be referred to... Figure 14B The method of engaging and disengaging the plunger 326 and the piston 500 is described.

[0256] Figure 2 The image shows the piston 500 before it locks into engagement with the plunger 326, with its plunger engagement mechanism 512 in a disengaged position or state. Figure 14B In this process, piston 400 is already advancing towards the distal side of plunger 326. In some embodiments, a controller 200 can be used ( Figure 14B The drive mechanism 402, operated by the piston, propels the piston 500 distally. In other embodiments, the piston can be moved distally manually.

[0257] Continue to refer to Figure 7Due to contact with the outer surface of the plunger portion 521, the latch 374 on at least one retaining member 368 of the plunger 326 deflects radially outward. After the latch 374 is positioned within the locking recess 527, for example when the upper surface of the connector 525 engages the drive shoulder 327 of the plunger 326, the distal movement of the piston 500 relative to the plunger 326 stops, and at least one retaining member 368 is resiliently deflected radially inward, such that the latch 374 is positioned within the locking recess 527. When at least one retaining member 368 is in Figure 14B In the position shown, plunger 326 is not locked into engagement with piston 500 because of the flexibility of the material between the first distal end 370 and the second proximal end 372 (see...). Figure 14A At least one retaining member 368 may deflect in a radially outward direction as the piston 500 moves proximally or the plunger 326 moves distally (e.g., due to removal of the syringe from the injector). As the plunger 326 contacts the piston 500, as... Figures 9-13J As shown, one or more release tabs 380 on the plunger 326 are aligned with the toothed portion 544 on the plunger engagement post 518.

[0258] refer to Figure 16 and 14C The plunger engagement sleeve 514 moves from the disengaged position or state to the engaged position or state. This movement of the plunger engagement sleeve 514 may be due to actuator de-energization and allows for the restoring force of the elastic member (e.g., referred to herein). Figures 9-13J The restoring elastic member 484 axially pushes the plunger engagement sleeve 514 in the distal direction. In other embodiments, this movement of the plunger engagement sleeve 514 may be due to the actuator being energized to axially push the plunger engagement sleeve 514 in the distal direction. For example, the actuator may be actuated by a rotary or linear motor to move the actuator from a disengaged position to an engaged position in the distal direction. Energizing the actuator in this way causes the plunger engagement sleeve 514 to move in the distal direction and establishes an elastic restoring force in the restoring elastic member. The distal movement of the plunger engagement sleeve 514 closes the receiving space 515 between the plunger engagement sleeve 514 and the plunger engagement post 518 to prevent one or more retaining members 368 of the plunger 326 from being removed from the receiving space 515 and from the latches 374 and locking grooves 527 of one or more flexible retaining members 368. Once the plunger engagement sleeve 514 is moved to the engagement position or state, at least one retaining member 368 of the plunger 326 is captured between the plunger engagement sleeve 514 and the plunger engagement post 518, such that proximal axial movement of the piston 500 causes a corresponding proximal axial movement of the plunger 326 within the syringe barrel. The piston 500 and the connected plunger 326 can then reciprocate within the syringe 318 of the syringe 300.

[0259] To unlock the syringe 300 from the syringe port of the injector and disengage the plunger 326 from the piston 500, the syringe 300 rotates clockwise or counterclockwise relative to the syringe port about the longitudinal axis of the syringe. Since the plunger 326 does not rotate substantially within the syringe barrel 318 due to friction, the rotation of the syringe 300 also causes the plunger 326 to rotate relative to the piston 500 about the longitudinal piston axis 520. Because one or more release tabs 380 on the plunger 326 align with the toothed portion 544 on the plunger engagement post 518, the rotation of the plunger 326 also causes the plunger engagement post 518 to rotate relative to the plunger release sleeve 558 from a first position to a second position. Because the guide pin 539 on the plunger engagement sleeve 514 is received within the longitudinal groove 538 of the plunger engagement post 518, the plunger engagement sleeve 514 also rotates with the rotation of the plunger engagement post 518. Rotation of the plunger engagement sleeve 514 causes the guide pin 539 to be guided along the inclined surface 566 of the plunger release sleeve 558 (see...). Figures 9-13J (, similar to the reference here) Figure 14A The described operation of the restoring elastic member 484 involves moving the plunger engagement sleeve 514 proximally and compressing the restoring elastic member. Furthermore, the rotation of the plunger engagement pin 518 about the longitudinal piston axis 520 can be similar to that described herein. Figures 18A-18B The described operation of the bias member 496 involves establishing potential energy within the bias member.

[0260] The movement of the guide pin 539 along the inclined surface 566 of the plunger release sleeve 558 causes the plunger engagement sleeve 514 to move axially from the engagement position or state in the proximal direction. Figures 18A-18B The disengaged position or state is shown. In some embodiments, the plunger engagement sleeve 514 can be moved proximally by energizing or de-energizing the actuator to retract the plunger engagement sleeve 514. The proximal movement of the plunger engagement sleeve 514 opens the receiving space 515 between the plunger engagement sleeve 514 and the plunger engagement post 518 to allow removal of the snap 374 and locking groove 527 of one or more flexible retaining members 368, and to allow removal of one or more retaining members 368 of the plunger 326 from the receiving space 515.

[0261] refer to Figures 9-13J This shows a piston 600 and a plunger engagement mechanism 612 according to another embodiment of the present disclosure. Figures 18A-18B The piston 600 and plunger engagement mechanism 612 shown herein are components referenced herein. Figures 9-13J The components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Therefore, Figures 18A-18B The reference marker in is used to indicate Figures 9-13J The same parts corresponding to the reference marks, except Figures 18A-18BThe first digit in the reference marker used has changed from "4" to "6". For example, although combined Figures 9-13J The piston described is indicated by the reference numeral "400", but Figures 18A-18B The piston in the designation is marked with reference numeral "600". This is in accordance with the preceding information regarding... Figure 18A The discussion of the piston 400 and plunger engagement mechanism 412, which are roughly shown in the figure, applies to... Figure 9 The piston 600 and plunger engagement mechanism 612 are shown in the figure, so the following discussion will only focus on the relative differences between the components shown in these figures.

[0262] refer to Figure 18A The plunger engagement mechanism 612 has a plunger engagement sleeve 614 and a plunger engagement pin 618. The plunger engagement sleeve 614 has a central opening 616, and the plunger engagement pin 618 is reciprocating within the central opening 616 of the plunger engagement sleeve 614 along the longitudinal piston axis 620. The plunger engagement pin 618 is reciprocated by an actuator, for example, see here. Figures 9-13J The actuator 422 is described. In some embodiments, the actuator may be a solenoid configured to be primarily in a disengaged state and may be engaged only during the period when the plunger 326 is connected to the piston. In other embodiments, the actuator may be a rotary motor, a linear motor, or a linear actuator. In some embodiments, the actuator is a linear actuator that can be manually reversed in the event of a power outage to the syringe.

[0263] The plunger engagement mechanism 612 is operable between an engaged position or state and a disengaged position or state. In the engaged position or state, the plunger engagement post 618 is positioned within the plunger engagement sleeve 614 to capture at least one retaining member 368 associated with the plunger 326 in a receiving space 615 between the plunger engagement sleeve 614 and the plunger engagement post 618. Conversely, in the disengaged position or state, the plunger engagement post 618 is positioned proximally relative to the plunger engagement sleeve 614 to allow removal of at least one retaining member 368 associated with the plunger 600 from the receiving space 615 between the plunger engagement sleeve 614 and the plunger engagement post 618.

[0264] Continue to refer to Figure 8CThe plunger engagement sleeve 614 has a hollow body 624, wherein at least a portion of the outer surface of the hollow body 624 defines at least a portion of the piston head 606. A distal portion or distal end 626 of the plunger engagement sleeve 614 is formed to be received within an internal cavity 340 of the plunger 326, while at least a portion of the plunger 326 (e.g., at least one retaining member 368) is configured to be received within a central opening 616. The central opening 616 extends through the hollow body 624 of the plunger engagement sleeve 614. The inner surface of the central opening 616 may have a chamfer 630 such that the inner diameter of the opening 616 narrows in the direction from the distal end of the hollow body 624 toward the proximal portion or proximal end. The ramp 630 may be configured to deflect at least one retaining member 368 associated with the piston 326 in a radially inward direction during distal movement of the piston head 606 relative to the plunger 326, through contact of the snap 374 of one or more flexible retaining members 368 with the plunger engagement sleeve 614. The ramp 630 may terminate at a locking rib 634. The outer surface 642 of the plunger engagement sleeve 614 may have a toothed portion 644, similar to those referenced herein. Figure 18B The described toothed portion 444. The toothed portion 644 may be configured to interact with one or more release tabs 380 on the plunger 326 during rotation of the plunger 326 relative to the piston 600 (e.g., Figures 9-13J (As shown).

[0265] refer to Figure 18B The diagram shows a plunger engagement post 618 separate from the plunger engagement mechanism 612. The plunger engagement post 618 has a shaft 672 with a proximal end 674 and a distal end 676. The distal end 676 of the shaft 672 has a tapered end face 678 configured to contact at least one retaining member 368 on the plunger 326 when the plunger engagement post 618 is in the engaged position to prevent the plunger 326 from being removed from the piston 600. The proximal end 674 of the shaft 672 is configured to connect to an actuator, similar to the one referenced herein. Figure 18B The described actuator 422 is used to move the plunger engagement pin 618 relative to the plunger engagement sleeve 614 between an engaged position or state and a disengaged position or state.

[0266] Continue to refer to Figure 8CThe plunger engagement post 618 also includes at least one groove 665 recessed into the body of the shaft 672 at its distal end 676. In some embodiments, the at least one groove 665 may be configured to receive at least one retaining member 368 of the plunger 326 when the plunger engagement post 618 is rotated about a longitudinal axis 667. The at least one groove 665 may be linearly or curvilinearly abutted between a boss 679 near the proximal end 674 of the shaft 672 and the distal end 676 of the shaft 672. In some embodiments, the at least one groove 665 may extend in a direction parallel to the longitudinal axis 667 of the plunger engagement post 618.

[0267] Continue to refer to Figure 18A Multiple grooves 665 are radially spaced apart from the longitudinal axis 667 along the circumference of the distal end 676 of the shaft 672. In embodiments providing more than two grooves 665, the grooves 665 may be evenly spaced apart from each other and separated from each other by the outer surface 667 of the shaft 672. In some embodiments, the number and spacing of the grooves 665 may correspond to the number and spacing of the retaining members 368 on the plunger 326. In an exemplary and non-limiting aspect, the six retaining members 368 have equal angular spacing, for example, as shown in the figure. Figure 18A As shown, the corresponding plunger engagement post 618 has six grooves 665, which are spaced 60 degrees apart from the adjacent grooves 665 on any side.

[0268] refer to Figures 13A-13J The proximal end 674 of shaft 672 is housed within a rotating mechanism 671, which is slidably mounted within the hollow body 624 of plunger engagement sleeve 614. In some embodiments, the rotating mechanism 671 may have a first portion 673 and a second portion 675. The first portion 673 is slidably mounted within the hollow body 624 and is fixed relative to the plunger engagement sleeve 614 without rotation, while the second portion 675 is fixed to the plunger engagement post 618 and is rotatable relative to both the first portion 673 and the plunger engagement sleeve 614. In some embodiments, the rotating mechanism 671 may be configured to rotate in one direction, for example, clockwise or counterclockwise about a longitudinal axis 620. For example, the rotating mechanism 671 may be a one-way clutch.

[0269] The structure of the plunger 326 and piston 600 has been described according to a non-limiting embodiment of the present disclosure, and the method of engaging and disengaging the plunger 326 and piston 600 will now be described.

[0270] Figure 2 A piston 600 is shown, with its plunger engagement mechanism 612 in an engaged position or state with the plunger 326. (See references herein.) Figures 9-14CThe plunger 326 can be connected to the piston 600 by moving the piston 600 distally to allow one or more retaining members 368 of the plunger 326 to be inserted into the receiving space 615 between the plunger engagement sleeve 614 and the plunger engagement post 618. In some embodiments, a controller 200 can be used ( Figure 2 The drive mechanism 402, operated by the piston, propels the piston 600 distally. In other embodiments, the piston 600 can be moved manually distally.

[0271] The piston 600 is axially advanced distally, causing at least one retaining member 368 of the plunger 326 to be flexibly received within the central opening 616 of the plunger engagement sleeve 614, such that at least one retaining member 368 is radially inwardly deflected due to contact between the snap 374 and the ramp 630. In embodiments with multiple retaining members 368, each retaining member 368 is deflected in a radially inward direction. In some embodiments, guide surfaces may be provided on the sides of the tapered end face 678 to assist the plunger engagement post 618 in rotating to the correct orientation, thereby self-aligning with the retaining member 368 on the plunger 326.

[0272] During the continued axial movement of piston 600 in the distal direction, latch 374 is radially inwardly deflected on locking rib 634 of piston engagement sleeve 614. After latch 374 is positioned proximally relative to locking rib 634, for example when drive shoulder 327 of plunger 326 engages corresponding drive boss 637 on piston 600, distal movement of piston 400 relative to plunger 326 stops, and at least one retaining member 368 is resiliently deflected in the radially outward direction, such that latch 374 is positioned proximally to locking rib 634. In this configuration, plunger engagement post 618 remains in the disengaged position or state, for example, as referred to herein. Figures 19-21B The actuator is activated as described. As the plunger 326 is connected to the piston 600, one or more release tabs 380 on the plunger 326 are aligned with the toothed portion 644 on the outer surface 642 of the plunger engagement sleeve 614.

[0273] As the plunger engagement post 618 moves distally from a disengaged state or position to an engaged state or position, the receiving space 615 between the plunger engagement sleeve 614 and the plunger engagement post 618 closes to prevent one or more retaining members 368 of the plunger 326 from being removed from the receiving space 615. As the plunger engagement post 618 moves to the engaged position or state, a latch 374 of at least one retaining member 368 of the plunger 326 is engaged between the outer surfaces 667 of the plunger engagement sleeve 614 and the plunger engagement post 618 near the locking rib 634. The piston 600 and the engaged plunger 326 can then reciprocate within the barrel 318 of the syringe 300. In some embodiments, the piston 600 can be advanced distally to deliver fluid from the syringe 300, or advanced proximally using a drive mechanism 402 operated by the controller 200 to fill the syringe 300 with fluid. Figures 19-21B ).

[0274] To unlock the syringe 300 from the syringe port of the injector and disengage the plunger 326 from the piston 600, the syringe 300 can rotate clockwise or counterclockwise relative to the syringe port about the longitudinal axis of the syringe. Rotation of the plunger 326 also causes rotation of the plunger engagement sleeve because one or more release tabs 380 on the plunger 326 align with the toothed portion 644 on the plunger engagement sleeve 614. Because the plunger engagement post 618 is connected to the plunger engagement sleeve 614 via a rotating mechanism 671, the plunger engagement post 618 does not rotate with the rotation of the plunger engagement sleeve 614. In this way, the retaining member 368 of the plunger 326 slides into the groove 665 on the plunger engagement post 618.

[0275] When the retaining member 368 of the plunger 326 is positioned in a groove 665 on the plunger engagement post 618, the receiving space 615 between the plunger engagement sleeve 614 and the plunger engagement post 618 opens to allow removal of one or more retaining members 368 of the plunger 326 from the receiving space 615 by distal bending movement of the latch 374 of at least one retaining member 368 on the locking rib 634. The syringe 300 can be pulled out distally or the plunger 600 can be retracted proximally to remove the plunger 326 from the piston 600. During this relative movement of the piston 326 and the plunger 600 in a direction away from each other, the latch 374 deflects on the locking rib 634 of the piston engagement sleeve 614 to allow removal of one or more retaining members 368 from the piston 600.

[0276] refer to Figures 9-13J The image shows a piston 700 and a plunger engagement mechanism 712 according to another embodiment of the present disclosure. Figures 19-21B The components of the piston 700 and plunger engagement mechanism 712 shown herein are the same as those referenced herein. Figures 9-13JThe components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Therefore, Figures 19-21B The reference marker in is used to indicate Figures 9-13J The same parts corresponding to the reference marks, except ​ The first digit in the reference mark used has changed from "4" to "7". This is because of the preceding information... ​ The discussion of the piston 400 and plunger engagement mechanism 412, which are roughly shown in the figure, applies to... Figure 19-21B The piston 700 and plunger engagement mechanism 712 are shown in the figure, so the following discussion will only focus on the relative differences between the components shown in these figures.

[0277] First refer to Figure 19 The piston 700 and plunger engagement mechanism 712 are shown with the injector (such as...). Figure 1 The syringe port 16 of the injector 10 shown is coupled. The piston 700 can be inserted within the syringe port 16 along the longitudinal piston axis 720, for example, through... Figure 2 The drive mechanism 402 shown reciprocates.

[0278] refer to Figure 20 An exploded view of the piston 700 and plunger engagement mechanism 712 is shown. The piston 700 has a body 704 and a piston head 706 located at the distal end of the body 704. The piston head 706 is configured to be removably connected to a plunger of a syringe, for example... Figure 7-8B The plunger 326 is shown. A plunger engagement mechanism 712 is integrated into the piston head 706. In some embodiments, at least a portion of the piston head 706 and / or the plunger engagement mechanism 712 may be made of a transparent or translucent material configured to allow light emitted by one or more lamps in the piston 700 to pass through, illuminating at least a portion of the syringe 300 and / or the plunger 326.

[0279] Continue to refer to Figure 20 The piston 700 has sensing elements 705, such as a pin 707 and a sensor 709. The pin 707 has a proximal end 713 configured to contact the sensor 709 when the distal end 715 of the pin 707 is pushed proximally, for example, due to contact between the plunger 326 and the distal end 715 of the pin 707. The pin 707 may extend along the longitudinal axis 720 of the piston 700 and may protrude through at least a portion of the piston head 706. The pin 707 is operable to sense contact with a surface (e.g., the surface of the plunger 326) and to the controller 200. Figure 2One or more signals are sent to control the movement of piston 700 based on sensed conditions. For example, initial contact between the distal end 715 of pin 707 and plunger 326 can cause pin 707 to move proximally, contacting sensor 709. Sensor 709 can be operatively connected to controller 200 such that when sensor 709 is activated via pin 707, sensor 709 controls the movement of the drive mechanism of piston 700. For example, the drive mechanism can stop or slow down from a first rate to a second slower rate, and the distal end 715 of pin 707 and plunger 326. Pin 707 can be biased to its distal position by spring 711.

[0280] Continue to refer to Figure 20 The plunger engagement mechanism 712 has a plunger engagement sleeve 714 and a plunger engagement pin 718, the plunger engagement sleeve 714 having a central opening 716. Due to the actuator 722 (e.g., Figures 21A-21B Upon activation (as shown), the plunger engagement post 718 can translate along the longitudinal piston axis 720 relative to the plunger engagement sleeve 714. In some embodiments, the plunger engagement post 718 can move axially between an engaged position and a disengaged position, in which the plunger 326 is locked engaged with the piston 700 because at least one retaining member 368 of the plunger 326 is captured between the plunger engagement sleeve 714 and the plunger engagement post 718, and in the disengaged position, the plunger 326 can be removed from the piston 700.

[0281] Continue to refer to Figure 20 The plunger engagement post 718 has a post portion 721 extending distally from a proximal portion 723. The plunger engagement post 718 also has a radial groove 737 configured to receive a guide pin (not shown). The post portion 721 of the plunger engagement post 718 has a locking lip 729 configured to interact with a snap 374 of at least one retaining member 368 of the plunger 326. Due to the contact of the snap 374 with the outer surfaces of the post portion 721 and / or the locking lip 729, the post portion 721 can be shaped to deflect at least one retaining member 368 in a radially outward direction. In this way, distal movement of the piston 700 relative to the plunger 326 causes at least one retaining member 368 to deflect radially outward due to the contact between the snap 374 and the post portion 721. In embodiments with multiple retaining members 368, each retaining member 368 deflects in a radially outward direction.

[0282] Continue to refer to Figure 20 The plunger engagement sleeve 714 has a hollow body 724, wherein at least a portion of the outer surface of the hollow body 724 defines at least a portion of the piston head 706. The distal portion or distal end 726 of the plunger engagement sleeve 714 is formed to be received within the internal cavity 340 of the plunger 326 (e.g., Figure 21A As shown), at least a portion of the plunger 326 (e.g., at least one retaining member 368) is configured to be received in a central opening 716. The central opening 716 extends through the hollow body 724 of the plunger engagement sleeve 714.

[0283] A portion of the inner surface 728 of the central opening 716, located at the distal end of the opening 716, may have a stepped inner diameter that decreases in diameter along a direction from the distal end of the plunger engagement sleeve 726 to the proximal end of the plunger engagement sleeve 714. For example, the opening 716 may have a first step 717 having a first inner diameter and a second step 719 positioned proximal to the first step 717, the second step 719 having a second diameter smaller than the first diameter of the first step 717. A ramp 730 may be provided between the first step 717 and the second step 719 for deflecting at least one retaining member 368 associated with the plunger 326 in a radially inward direction during the connection of the plunger 326 to the distal portion or distal end 726 of the plunger engagement sleeve 714.

[0284] According to a non-limiting embodiment of this disclosure, plunger 326 has been described (see references herein). Figure 6-8C (The publicly available information) and the structure of piston 700, will now be referenced. Figures 21A-21B The method of engaging and disengaging the plunger 326 and the piston 700 is described. Figures 21A-21B A portion of syringe 300 is shown.

[0285] Figure 21A The image shows a piston 700 prior to locking engagement with plunger 326, with its plunger engagement mechanism 712 in a disengaged position or state. In some embodiments, a controller 200 (…) is used… Figure 2 The drive mechanism 402, operated by the piston, propels the piston 700 distally. In other embodiments, the piston can be moved manually in the distal direction.

[0286] As the piston 700 advances distally, the latch 374 on at least one retaining member 368 of the plunger 326 deflects radially outward due to contact with the locking lip 729 on the plunger portion 721. The plunger engagement post 718 is in its disengaged position and moves axially relative to the plunger engagement sleeve 714 distally, allowing the retaining member 368 to deflect radially outward into the space defined by the first step 717. After the latch 374 is positioned proximally relative to the locking lip 729, at least one retaining member 368 can be resiliently deflected radially inward, for example, due to the resilient flexibility of the retaining member 368 engaging with the ramp 730 between the first and second steps 717, 719. When at least one retaining member 368 is in Figure 21AIn the position shown, the plunger 326 is not locked into engagement with the piston 700 because at least one retaining member 368 can be flexibly deflected radially outward as the piston 700 moves proximally or the plunger 326 moves distally (e.g., due to removal of the syringe from the injector), as described herein.

[0287] refer to Figure 21B By moving proximally along the longitudinal piston axis 720, the plunger engagement pin 718 moves from a disengaged position or state to an engaged position or state. This movement of the plunger engagement pin 718 may be due to actuator de-energization and allows for the movement of a restoring elastic member (e.g., referred to herein). Figure 9-13J The described restoring elastic member 484 axially pushes the plunger engagement post 718 proximally, or alternatively, moves the plunger engagement post 718 proximally by energizing an actuator. The proximal movement of the plunger engagement post 718 locks at least one retaining member 368 and a latch 374 within the space defined by the second step 719 of the plunger engagement sleeve 714. Due to the combination of the smaller second diameter of the second step 719 and the increased diameter of the locking lip 729, one or more retaining members 368 of the plunger 326 are captured within the receiving space 715 between the plunger engagement sleeve 714 and the plunger engagement post 718, such that reciprocating axial movement of the piston 700 causes a corresponding reciprocating axial movement of the plunger 326 within the syringe barrel 318. To unlock the plunger 326 from the plunger engagement mechanism 712, the plunger engagement post 718 is moved to a disengaged position by axial movement of the plunger engagement post 718 in the distal direction, while the locking lip 729 moves distally, allowing the latch 374 of one or more retaining members 368 to move around the locking lip 729 in the first step 717, and allowing the removal of one or more retaining members 368 of the plunger 326 from the receiving space 715 between the plunger engagement sleeve 714 and the plunger engagement post 718.

[0288] refer to Figures 22A-22E This shows a piston 800 and a plunger engagement mechanism 812 according to another embodiment of the present disclosure. Figures 22A-22E The components of the piston 800 and plunger engagement mechanism 812 shown herein are the same as those referenced herein. Figure 9-13J The components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Therefore, Figures 22A-22E The reference marker in is used to indicate Figure 9-13J The same parts corresponding to the reference marks, except Figures 22A-22E The leading number in the reference mark used has changed from "4" to "8". This is because of the preceding information... Figure 9-13J The discussion of the piston 400 and plunger engagement mechanism 412, which are roughly shown in the figure, applies to... Figures 22A-22EThe piston 800 and plunger engagement mechanism 812 are shown in the figure, so the following discussion will only focus on the relative differences between the components shown in these figures.

[0289] refer to Figure 22A The piston 800 has a body 804 and a piston head 806 located at the distal end of the body 804. The piston head 806 is configured to be removably connected to a plunger of a syringe, for example... Figure 8C The plunger 326 is shown. A plunger engagement mechanism 812 is integrated into the piston head 806. In some embodiments, at least a portion of the piston head 806 and / or the plunger 326 may be made of a transparent or translucent material configured to allow light emitted by one or more lamps 803 in the piston 800 to pass through, illuminating at least a portion of the plunger 326 and / or the syringe 300.

[0290] Piston 800 has sensing elements 805, such as sensing sleeve 807 and sensor 809. Sensing sleeve 807 has a proximal end 813 configured to interact with sensor 809, for example, due to contact between the distal end 815 of piston 326 and the distal end 815 of sensing sleeve 807 when the distal end 815 of sensing sleeve 807 is pushed proximally. Sensing sleeve 807 may extend along longitudinal axis 820 of piston 800 and may be recessed within piston head 806. Sensing sleeve 807 is operable to sense contact with a surface (e.g., the surface of piston 326), and controller 200 may be signaled based on the sensed condition to control movement of piston 800. In some embodiments, the distal end 815 of sensing sleeve 807 may be configured to contact one or more retaining members 368 of piston 326 when piston 326 is connected to piston 800. Initial contact between the distal end 815 of the sensing sleeve 807 and one or more retaining members 368 of the plunger 326 can cause the sensing sleeve 807 to retract proximally, thereby activating the sensor 809. The sensor 809 can be operatively connected to the controller 200 and the drive mechanism of the piston 800, such that when the sensor 809 is activated by the sensing sleeve 807, the sensor 809 sends a signal to the controller 200 to control the movement of the drive mechanism. For example, the drive mechanism can stop or slow down from a first rate to a second, slower rate. The sensing sleeve 807 can be biased to its distal position by a biasing member (e.g., a spring 817).

[0291] The plunger engagement mechanism 812 has a plunger engagement sleeve 814 and a plunger engagement pin 818, the plunger engagement sleeve 814 having a central opening 816. Due to the actuator (e.g., referred to herein)... Figure 9-13JUpon activation of the described actuator 422), the plunger engagement post 818 can translate along the longitudinal piston axis 820 relative to the plunger engagement sleeve 814. In some embodiments, the plunger engagement post 818 can move axially between an engaged position and a disengaged position, in which the plunger 326 is locked engaged with the piston 800 due to a latch 374 that captures at least one retaining member 368 of the plunger 326 below the locking rib 834 on the plunger engagement sleeve 814 and the plunger engagement post 818, and in the disengaged position, the plunger 326 can be removed from the piston 800.

[0292] The plunger engagement sleeve 814 has a hollow body 824, wherein at least a portion of the outer surface of the hollow body 824 defines at least a portion of the piston head 806. A distal portion or distal end 826 of the plunger engagement sleeve 814 is formed to be received within an internal cavity 340 of the plunger 326, while at least a portion of the plunger 326 (e.g., at least one retaining member 368) is configured to be received within a central opening 816. The central opening 816 extends through the hollow body 824 of the plunger engagement sleeve 814.

[0293] The inner surface of the central opening 816 has a locking rib 834 that projects radially inward from the inner surface 828. The locking rib 834 is configured to deflect at least one retaining member 368 associated with the plunger 326 in a radially inward direction during the engagement of the plunger 326 with the distal portion or distal end of the plunger engagement sleeve 814. In some embodiments, the locking rib 834 extends continuously or discontinuously around the inner surface 828 of the hollow body 824 of the plunger engagement sleeve 814 and defines a surface for at least one snap 368 on at least one retaining member 368 on the engaging plunger 326 to prevent the plunger 326 from being removed from the piston 800 when the plunger 326 is locked into engagement with the plunger engagement mechanism 812, as described herein.

[0294] The structure of the plunger 326 and piston 800 has been described according to a non-limiting embodiment of this disclosure, and will now be referred to... Figures 22A-22E Describes the method of engaging and disengaging the plunger 326 and the piston 800.

[0295] Figure 22A The piston 700 is shown with its plunger engagement mechanism 812 in a disengaged position or state, prior to locking engagement with the plunger 326. In some embodiments, a controller 200 can be used... Figure 2 The drive mechanism 402, operated by the piston, propels the piston 800 distally. In other embodiments, the piston can be moved manually in the distal direction.

[0296] from Figure 22A Move to Figure 22BAs the piston 800 advances toward the plunger 326, at least one retaining member 368 on the plunger 326 contacts the sensing sleeve 807, causing the sensing sleeve 807 to move proximally toward the sensor 809. Due to contact with the locking rib 834 on the plunger engaging sleeve 814, the latch 374 on at least one retaining member 368 of the plunger 326 deflects radially inward. The plunger engaging post 818 is in its disengaged position, for example, retracted proximally. When at least one retaining member 368 is in... Figure 22B In the position shown, the plunger 326 is not locked into engagement with the piston 800 because at least one retaining member 368 can be flexibly deflected in a radially inward direction as the piston 800 moves proximally or the plunger 326 moves distally (e.g., due to removal of the syringe from the injector).

[0297] refer to Figure 22C When the sensing sleeve 807 moves proximally due to contact with at least one retaining member 368 of the plunger 326, the sensor 809 detects the presence of the sensing sleeve 807 and actuates the actuator 822 to axially move the plunger engagement post 718 distally from a disengaged position or state to an engaged position or state. This movement of the plunger engagement post 718 may be due to de-energization of the actuator 822. In other embodiments, the movement of the plunger engagement post 718 may be due to energizing the actuator 822 (e.g., a solenoid) or by moving the actuator through operation of a motor.

[0298] As the plunger engagement post 818 moves from a disengaged state or position to an engaged state or position, the receiving space 815 between the plunger engagement sleeve 814 and the plunger engagement post 818 near the locking rib 834 closes to prevent the latches 374 of one or more retaining members 368 of the plunger 326 from being removed from the receiving space 815. As the plunger engagement post 818 moves to the engaged position or state, the latches 374 of at least one retaining member 368 of the plunger 326 are engaged between the locking rib 834 on the plunger engagement sleeve 814 and the plunger engagement post 818. The piston 800 and the connected plunger 326 can then reciprocate within the syringe barrel 318. In some embodiments, the piston 800 can be advanced distally to deliver fluid from the syringe 300, or proximally using a drive mechanism 402 operated by the controller 200 to fill the syringe 300 with fluid. Figure 2 ).

[0299] refer to Figure 22DTo unlock plunger 326 from plunger engagement mechanism 812, plunger engagement post 818 is moved to a disengaged position by axial movement in the distal direction, for example by a stored restoring force of an actuator (as described herein) or a biasing member. This removes one or more locking members 368 of plunger 326 from the receiving space 815 between plunger engagement sleeve 814 and plunger engagement post 718. Removal of plunger 326 from piston 800 allows sensing sleeve 807 to move distally due to the restoring force provided by spring 817. Figure 22E ).

[0300] refer to Figures 23A-23G This shows a piston 900 and a plunger engagement mechanism 912 according to another embodiment of the present disclosure. Figures 23A-23G Some components of the piston 900 and plunger engagement mechanism 912 shown herein are referenced herein. Figure 9-13J The components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Due to the preceding... Figure 9-13J Some features of the piston 400 and plunger engagement mechanism 412, which are generally shown in the discussion, are applicable to... Figures 23A-23G The piston 900 and plunger engagement mechanism 912 are shown in the figure, so the following discussion will only focus on the relative differences between the components shown in these figures.

[0301] refer to Figure 23A The plunger 326 has at least one retaining member 368 with a snap-fit, the snap-fit ​​374 projecting radially outward relative to the longitudinal axis 334 of the plunger. The snap-fit ​​374 is shaped to be received within at least a portion of the piston engagement mechanism 912. In some embodiments, the snap-fit ​​374 has a circular or angled snap-fit ​​surface 375 forming an acute or obtuse angle relative to the longitudinal axis 334 of the plunger. The angled snap-fit ​​surface 375 is configured to interact with at least a portion of the plunger engagement mechanism 912 during engagement of the plunger 326 with the piston 900, as described herein. The at least one retaining member 368 may also have at least a circular or an angled release surface 369. The angled release surface 369 may be disposed on at least a portion of the snap-fit ​​374, for example, opposite to the angled snap-fit ​​surface 375. The circular or angled release surface 369 forms an acute or obtuse angle relative to the longitudinal axis 334 of the plunger in a direction opposite to the arc or angle of the circular or angled snap-fit ​​surface 375. As described herein, the circular or angled release surfaces 369 are configured to interact with at least a portion of the plunger engagement mechanism 912 during disengagement of the plunger 326 from the piston 900. In various embodiments, without additional support, the frictional and locking interactions between the circular or angled release surfaces 369b are insufficient to lock the plunger 326 into contact with the plunger engagement mechanism 912 of the piston 900.

[0302] Piston 900 can extend and retract from the housing of fluid injectors 10 and 100. Figure 1 and 3 The piston 900 includes a rod 901 and a piston head 920 formed on the distal end of the rod 900. In some embodiments, the piston head 920 may extend radially outward beyond the radial edge of the rod 900. The piston head 920 may be structurally substantially cylindrical and have a piston cavity 940 configured to receive at least a portion of the plunger 326, such as at least one retaining member 368, when the plunger 326 is engaged with the piston 900. The piston cavity 940 may have at least one locking lip 950 projecting radially inward from an inner surface of the piston cavity 940. The at least one locking lip 950 is configured to engage at least a portion of the retaining member 368, such as a snap 374. The at least one locking lip 950 may be continuous or discontinuous in the circumferential direction around the piston cavity 940.

[0303] In some examples, at least one locking lip 950 has a rounded or angled distal surface 960 and a rounded or angled proximal surface 970. The rounded or angled distal surface 960 is arcuate or angled in the same direction as the rounded or angled snap-fit ​​surface 375 of the plunger 326. In this way, during the connection process between the piston 900 and the plunger 326, the distal surface 960 engages the snap-fit ​​surface 375 to flexibly and elastically deflect one or more retaining members 368 radially inward toward the longitudinal axis 334 of the plunger, thereby allowing the plunger 326 to be inserted into the piston chamber 940. The rounded or angled proximal surface 970 is arcuate or angled in the opposite direction to the rounded or angled distal surface 960. The rounded or angled proximal surface 970 is arcuate or angled in the same direction as the rounded or angled release surface 369 of the plunger 326. In this manner, when the piston 900 and / or plunger 326 move axially to disengage the plunger 326 from the piston 900, the proximal surface 970 engages the release surface 369. The engagement between the release surface 369 on the plunger 326 and the proximal surface 970 on the piston 900 causes one or more retaining members 368 to deflect radially inward toward the longitudinal axis 334 to allow the plunger 326 to be pulled back from the piston chamber 940.

[0304] refer to Figures 23A-23G The piston 900 has a locking member 980, which is configured to lock the plunger 326 relative to the piston 900. The locking member 980 can be in a first position ( Figure 23D ) and second position ( Figure 23EAxial movement between the piston 900 and piston 326. In some examples, the locking member 980 is movable such that it extends at least partially within the piston chamber 940. When extended in the second position, the locking member 980 is inserted into the cavity 340 of the plunger 326 to prevent at least one retaining member 368 from deflecting in a radially inward direction. For example, in the second engaged position, the locking member 980 locks the latch 374 against at least one locking lip 950 by abutting the release surface 369 on the retaining plunger 326 against the proximal surface 970 on the piston 900, such that the latch 374 cannot move past at least one locking lip 950. In some embodiments, a sensing member (not shown), such as a spring-loaded pin connected to a sensor, may be provided for sensing contact with a surface (e.g., the surface of the plunger 326) and controlling the movement of the piston 900 based on the sensed condition.

[0305] The structure of the plunger 326 and piston 900 has been described according to a non-limiting embodiment, and reference will now be made to... Figures 23A-23G Describe the engagement and disengagement of plunger 326 and piston 900. For clarity, Figure 23A The syringe 12 shown is from Figure 23B-23G The rest is omitted.

[0306] To engage the plunger 326 with the piston 900, first insert the syringe 12 into the syringe port 16 of the fluid injector 10. Figure 1 ) or pressure sleeve 15 ( Figure 3 Once the syringe 12 is inserted into the syringe port 16, various locking mechanisms (not shown) can be used to retain the syringe 12 within the syringe port 16 or within the pressure sheath to prevent the syringe 12 from disengaging from the syringe port 16. Initially, the plunger 326 can be positioned at the proximal end 20 of the syringe barrel 18. The piston 900 can then be advanced distally toward the plunger 326 for engagement of the piston head 920 with the plunger 326.

[0307] refer to Figures 23A-23B Piston 900 propels axially in the distal direction ( Figures 23A-23BArrow A in the diagram causes the angled distal surface 960 of the piston head 920 to contact at least one locking member 368 of the plunger 326. Initially, the angled distal surface 960 contacts a latch 374, such as a latch surface 375, of at least one retaining member 368. Because the latch 374 projects radially outward relative to at least one retaining member 368, the latch 374 is positioned at a greater radial distance from the longitudinal axis 334 of the plunger than the inner surface of the piston cavity 940, which is close to the angled distal surface 960. In this way, due to the contact between the latch surface 375 on the plunger 326 and the distal surface 960 on the piston 900, the continued distal movement of the piston 900 causes at least one retaining member 368 to be flexibly and elastically deflected radially inward. Figure 23B In an example with multiple retaining members 368, each retaining member 368 is radially inwardly deflected relative to the longitudinal axis 334 of the plunger.

[0308] refer to Figure 23C During the sustained axial movement of the piston 900 in the distal direction, the latch 374 is axially advanced through at least one lip 950 of the piston head 920. Due to the restoring force generated during the radial deflection of at least one flexible retaining member 368, the latch 374 latches radially outward into a recess 990 located proximal to at least one locking lip 950. Figure 23A The plunger 326 is thus releasably retained within the piston chamber 940. To lock the plunger 326 to the piston 900 and prevent its removal from the piston 900, the locking member 980 is moved in the axial direction (arrow B), from the first position (…). Figure 23D Extending to the second position ( Figure 23E In the second position, the locking member 980 is positioned such that the retaining member 368 is locked between the inner surface of the piston chamber 940 and the outer surface of the locking member 980, and cannot be flexibly deflected inward to disengage. The locking member 980 prevents the retaining member 368 from moving radially inward, thereby preventing the plunger 326 from disengaging from the piston 900. In this way, the piston 900 can move in a proximal or distal direction, resulting in a corresponding movement of the plunger 326. The locking member 980 can be moved between the disengaged and engaged positions by an electromechanical actuator (e.g., a solenoid actuator, rotary motor, linear motor, etc.). Figures 23A-23B As shown, the locking member 980 can be reciprocated using a rotary motor to rotate the mating surfaces of the threaded screw driver.

[0309] To unlock syringe 12 from syringe port 16 and disengage plunger 326 from piston 900, by... Figure 23FThe locking member 980 is moved axially in the direction of arrow C, moving from the second position to the first position. When the locking member 980 is in the first position, it is moved distally via syringe 12. Figure 23G As indicated by arrow D), the plunger 326 moves along the piston 900 in a proximal direction, disengaging the plunger 326 from the piston 900. This relative movement between the piston 900 and the plunger 326 causes the angled release surface 369 of the retaining member 368 to engage the angled proximal surface 970 of the piston 900. Continued movement of the plunger 326 away from the piston 900 causes the retaining member 368 to deflect radially inward over the lip 950. After overcoming the lip 950, the retaining member 368 springs back radially outward, thereby completely disengaging the plunger 326 from the piston 900.

[0310] refer to Figures 24A-24C This shows a piston 1000 and a plunger engagement mechanism 1012 according to another embodiment of the present disclosure. Figures 24A-24C The components of the piston 1000 and plunger engagement mechanism 1012 shown herein are the same as those referenced herein. Figure 9-13J The components of the piston 400 and the plunger engagement mechanism 412 described are substantially similar or identical. Therefore, Figures 24A-24C The reference marker in is used to indicate Figure 9-13J The same parts corresponding to the reference marks, except Figures 24A-24C The leading number in the reference mark used has changed from "4" to "10". This is because of the preceding information... Figure 9-13J The discussion of the piston 400 and plunger engagement mechanism 412, which are roughly shown in the figure, applies to... Figures 24A-24C The piston 1000 and plunger engagement mechanism 1012 shown in the figure are discussed below only, and therefore only the relative differences between the components shown in these figures will be discussed below.

[0311] refer to Figure 24B The plunger engagement mechanism 1012 has a plunger engagement sleeve 1014 and a plunger engagement pin 1018. The plunger engagement sleeve 1014 has a central opening 1016, and the plunger engagement pin 1018 is reciprocating within the central opening 1016 of the plunger engagement sleeve 1014 along the direction of the longitudinal piston axis 1020. The plunger engagement pin 1018 is reciprocated by an actuator, such as the one described herein. Figure 9 The actuator 422 described herein or other embodiments of the plunger engagement mechanism described herein. The plunger engagement mechanism 1012 is operable between an engaged position or state and a disengaged position or state. In the engaged position or state, the plunger engagement post 1018 can be positioned within the plunger engagement sleeve 1014 to capture at least one retaining member 368 associated with the plunger 326 in a receiving space 615 between the plunger engagement sleeve 1014 and the plunger engagement post 1018 (e.g., Figure 24C(As shown). Conversely, in the disengaged position or state, the plunger engagement post 1018 can be positioned relative to the plunger engagement sleeve 1014 to allow removal from the receiving space 1015 between the plunger engagement sleeve 1014 and the plunger engagement post 1018 at least one retaining member 368 associated with the plunger 326.

[0312] refer to Figure 24B The plunger engagement sleeve 1014 has a hollow body 1024, wherein at least a portion of the outer surface of the hollow body 1024 defines at least a portion of the piston head 1006. A distal portion or distal end 1026 of the plunger engagement sleeve 1014 is formed to be received within an internal cavity 340 of the plunger 326, while at least a portion of the plunger 326 (e.g., at least one retaining member 368) is configured to be received within a central opening 1016. The central opening 1016 extends through the hollow body 1024 of the plunger engagement sleeve 1014. The outer surface 1042 of the plunger engagement sleeve 1014 may have a toothed portion 1044. The toothed portion 1044 may be configured to interact with a corresponding toothed portion 329 on the plunger 326 during rotation of the plunger 326 relative to the piston 1000.

[0313] The plunger engagement sleeve 1014 also includes at least one locking groove 1065 recessed into the inner surface of the central opening 1016. In some embodiments, the at least one groove 1065 may be configured to receive a snap 374 of at least one retaining member 368 of the plunger 326 when the plunger 326 is engaged with the plunger engagement sleeve 1014.

[0314] The plunger engagement post 1018 has a shaft 1072 with a proximal end 1074 and a distal end 1076. The distal end 1076 of the shaft 1072 has a tapered end face 1078 configured to contact at least one retaining member 368 on the plunger 326, so as to flexibly deflect at least one retaining member 368 in a radially inward direction when the piston 1000 contacts the plunger 326. When moved to the engaged position, the plunger engagement post 1018 prevents the plunger 326 from being removed from the piston 1000 (e.g., when moved to the engaged position). Figure 24C As shown), for example, by locking at least one retaining member 368 of the plunger 326 under a locking recess 1065 on the plunger engagement sleeve 1014 via a snap 374. The proximal end 1074 of the shaft 1072 is configured to connect to an actuator (similar to the one referenced herein). Figure 9-13J The described actuator 422) is used to move the plunger engagement pin 1018 relative to the plunger engagement sleeve 1014 between an engaged position or state and a disengaged position or state.

[0315] refer to Figure 24CThe proximal end 1074 of shaft 1072 is received within a rotating mechanism 1071, which is slidably mounted within the hollow body 1024 of plunger engagement sleeve 1014. In some embodiments, the rotating mechanism 1071 may be configured to rotate in one direction, for example, clockwise or counterclockwise about the longitudinal piston axis 1020, as described in various embodiments herein. For example, the rotating mechanism 1071 may be a one-way clutch.

[0316] The structure of the plunger 326 and the piston 1000 has been described according to a non-limiting embodiment of the present disclosure, and the method of engaging and disengaging the plunger 326 and the piston 1000 will now be described.

[0317] Figure 24C The piston 1000 is shown, with its plunger engagement mechanism 1012 engaged with the plunger 326 in an engaged position or state. (See references herein.) Figure 13A-13J The plunger 326 can be connected to the piston 1000 by moving the piston 1000 distally to allow one or more retaining members 368 of the plunger 326 to be inserted into the receiving space 1015 between the plunger engaging sleeve 1014 and the plunger engaging post 1018, such that the snap 374 is located within the locking recess 1065. In some embodiments, a controller 200 ( Figure 2 The drive mechanism 402, operated by the piston, propels the piston 1000 distally. In other embodiments, the piston 1000 can be moved manually in the distal direction.

[0318] The piston 1000 is axially advanced in a distal direction, causing at least one retaining member 368 of the plunger 326 to be received within the central opening 1016 of the plunger engagement sleeve 1014, such that at least one retaining member 368 is radially inwardly deflected due to contact between the snap 374 and the inner surface of the plunger engagement sleeve 1014. In embodiments with multiple retaining members 368, each retaining member 368 is deflected in a radially inward direction.

[0319] During the continued axial movement of the piston 1000 in the distal direction, the latch 374 deflects radially outward into the locking groove 1065 of the piston engagement sleeve 1014. After the latch 374 is positioned within the locking groove 1065, the distal movement of the piston 1000 relative to the plunger 326 ceases, for example, due to the engagement between the toothed portion 329 on the plunger 326 and the toothed portion 1044 on the outer surface 1042 of the plunger engagement sleeve 1014. The plunger engagement pin 1018 is in the disengaged position or state, and the plunger 326 is connected to the piston 1000, with the toothed portion 329 on the plunger 326 aligned with the toothed portion 1044 on the outer surface 1042 of the plunger engagement sleeve 1014.

[0320] As the plunger engagement post 1018 moves from a disengaged state or position to an engaged state or position, the receiving space 1015 between the plunger engagement sleeve 1014 and the plunger engagement post 1018 closes to prevent one or more retaining members 368 of the plunger 326 from being removed from the receiving space 1015 and the locking groove 1065. As the plunger engagement post 1018 moves to the engaged position or state, at least one retaining member 368 of the plunger 326 is captured between the outer surfaces of the plunger engagement sleeve 1014 and the plunger engagement post 418. The piston 1000 and the engaged plunger 326 can then reciprocate within the barrel 318 of the syringe 300. In some embodiments, the piston 1000 can be advanced distally to deliver fluid from the syringe 300, or advanced proximally using a drive mechanism 402 operated by the controller 200 to fill the syringe 300 with fluid. Figure 2 ).

[0321] To unlock the syringe 300 from the syringe port of the injector and disengage the plunger 326 from the piston 1000, the syringe 300 rotates clockwise or counterclockwise relative to the syringe port about the longitudinal axis of the syringe. Rotation of the plunger 326 also causes rotation of the plunger engagement sleeve 1014 because the toothed portion 329 on the plunger 326 aligns with the toothed portion 1044 on the plunger engagement sleeve 1014. Because the plunger engagement pin 1018 is connected to the plunger engagement sleeve 1014 via a rotating mechanism 1071, the plunger engagement pin 1018 does not rotate with the rotation of the plunger engagement sleeve 1014. In some embodiments, the plunger engagement pin 1018 can be activated by an actuator (e.g., see here). Figure 9-13J The described actuator 424) moves between an engaged position and a disengaged position.

[0322] Figure 25A and 25B An embodiment of a piston-plunger engagement system according to another embodiment is shown. Figure 25A A system in the disengaged position is shown, wherein the plunger includes an inwardly facing engagement flange or snap 2774 extending proximally from the inner surface of the plunger base. The piston includes at least one flexible retaining member 2750 having at least one retaining snap 2755 configured to engage a corresponding engagement flange or snap 2774 of the plunger base. In the disengaged position, a movable locking member 2798 is configured in a distal first position such that the locking member 2798 does not engage with at least one flexible retaining member 2750 of the piston 2700. Figure 25B As shown, the piston-plunger engagement system is in the engaged position, wherein the movable locking member 2798 moves proximally, for example by a motor, solenoid, or cam system. When the locking member 2798 moves proximally, the proximal surface 2799 (e.g., Figure 25A and25B The angled surfaces shown contact and engage at least one flexible retaining member 2750, which bends the retaining member 2750 radially outward. As the retaining member 2750 moves radially outward, at least one retaining latch 2755 engages at least one inwardly facing engagement flange or latch 2774, locking the plunger base to the piston. Typically, the at least one inwardly facing engagement flange or latch 2774 is substantially inflexible, for example, due to structural strength or the outer surface of the plunger engagement sleeve 2714 preventing the engagement flange or latch 2774 from bending radially outward and disengaging from at least one retaining latch 2755 of the at least one flexible retaining member 2750. Moving the locking member 2798 distally releases the force applied to the at least one flexible retaining member 2750, thereby allowing the retaining member 2750 to return to a non-bent disengaged position, in which at least one retaining latch 2755 does not contact or engage at least one inwardly facing engagement flange or latch 2774, and allowing the plunger to be removed from the piston.

[0323] In some embodiments, a restoring elastic member 2784 is configured to bias the locking member 2798 toward a disengaged or engaged position. For example, the restoring elastic member 2784 may be a compression spring configured to bias the locking member 2798 in a distal direction toward the disengaged position. In this way, the locking member 2798 is in a normally disengaged state, such that the plunger can disengage from the locking member 2798 in the event of a power failure. In other embodiments, the restoring elastic member 2784 may be a tension spring configured to bias the locking member 2798 in a proximal direction toward the engaged position. In such embodiments, the locking member 2798 is in a normally engaged position and must be moved to the disengaged position, for example, using references herein. Figure 9 The actuator 422 is described to allow the plunger to be removed from the locking member 2798.

[0324] refer to Figure 26 According to another embodiment of this disclosure, a piston 1100 having a plunger engagement mechanism 1112 is shown. In some embodiments, the piston 1100 may be configured to engage with... Figure 1 and 3 The injectors 10 and 100 shown are used together. In other embodiments, piston 1100 may be configured for use with any fluid injector configured for medical purposes (e.g., injection of contrast agents and saline solution during contrast-enhanced imaging). Piston 1100 is configured to reciprocate within the housing of the syringe via a drive mechanism. The drive mechanism may include, for example, an electric motor 402 ( Figure 2 ), hydraulic system, pneumatic system, or any combination thereof. Controller 200 ( Figure 2It can be configured to control the operation of the drive mechanism, and thus control the reciprocating movement of the piston 1100.

[0325] Piston 1100 has a body 1104 and a piston head 1106 located at the distal end of the body 1104. Piston head 1106 is configured to be removably connected to plunger 326 of syringe 300. Piston head 1106 has a generally cylindrical structure with a partially conical distal end configured to be received within at least a portion of the internal cavity 340 of plunger 326. In some embodiments, piston head 1106 and / or at least a portion of plunger 326 may be made of a transparent or translucent material configured to allow light emitted by one or more lamps in piston 1100 to pass through for illuminating plunger 326 and / or at least a portion of syringe 300.

[0326] The piston head 1106 has a plunger engagement mechanism 1112 configured to releasably engage the plunger 326 to facilitate reciprocating drive of the plunger 326 within the barrel of the syringe 300 and to rapidly remove the syringe 300 and plunger 326 from the piston head 1106 and the fluid injector at the end of the injection process. The plunger engagement mechanism 1112 has a plunger engagement sleeve 1114 and a plunger engagement pin 1118. The plunger engagement sleeve 1114 has a central opening 1116, and the plunger engagement pin 1118 is reciprocating within the central opening 1116 of the plunger engagement sleeve 1114 along the longitudinal piston axis 1120. The plunger engagement pin 1118 is reciprocated by an actuator 1122 of the fluid injector. The plunger engagement mechanism 1112 is operable between an engaged position or state and a disengaged position or state. In the engaged position or state, the plunger engagement post 1118 can be positioned within the plunger engagement sleeve 1114 to capture at least one retaining member 368 associated with the plunger 326 in a receiving space 1115 between the plunger engagement sleeve 1114 and the plunger engagement post 1118. Conversely, in the disengaged position or state, the plunger engagement post 1118 can be positioned relative to the plunger engagement sleeve 1114 to allow removal of at least one retaining member 368 associated with the plunger 1100 from the receiving space 1115 between the plunger engagement sleeve 1114 and the plunger engagement post 1118.

[0327] Actuator 1122 may be configured to have an engaged state for moving one of the plunger engagement sleeve 1118 and the plunger engagement post 1118 to an engaged position and a disengaged state for moving one of the plunger engagement sleeve and the plunger engagement post to a disengaged position. In some embodiments, actuator 1122 may automatically move to the disengaged state, for example, during a power outage of actuator 1122. In some embodiments, actuator 1122 may be in the engaged state only during proximal movement of piston 1100. In some embodiments, actuator 1122 may be a solenoid configured to be primarily in the disengaged state and may be in the engaged state only during the engagement of plunger 326 with piston 1100. In other embodiments, actuator 1122 may be a rotary motor, a linear motor, or a linear actuator. In some embodiments, actuator 1122 is a linear actuator that can be manually reversed in the event of a power outage of the injector. In various embodiments, moving one of the plunger engagement sleeve 1118 and the plunger engagement post 1118 to a disengaged state to remove the plunger 326 from the piston 1100 can be achieved by rotating the plunger 326 relative to the piston 1100, as described herein.

[0328] refer to Figure 27A The description includes a plunger engagement sleeve 1114 according to one embodiment. The plunger engagement sleeve 1114 has a hollow body 1124, wherein at least a portion of the outer surface of the hollow body 1124 defines at least a portion of a piston head 1106. Figure 26 In some embodiments, the distal portion or distal end 1126 of the hollow body 1124 may have a conical shape, which is configured to correspond to the shape of the internal cavity 340 of the conical portion of the plunger 326. At least a portion of the plunger 326, such as at least one retaining member 368, is configured to be received within a central opening 1116. The central opening 1116 extends through the hollow body 1124 of the plunger engagement sleeve 1114. The proximal end or proximal portion 1132 of the hollow body 1124 may be configured to be received within a plunger release sleeve 1158 (e.g., Figure 28 (As shown).

[0329] At least a portion of the outer surface 1142 of the hollow body 1124 has a toothed portion 1144, which is configured to interact with one or more release tabs 380 on the plunger 326 during attachment of the plunger 326 to and removal of the plunger 326 from the plunger engagement mechanism 1112, as described herein. The toothed portion 1144 has one or more plunger release teeth 1145 projecting from the outer surface 1142. The one or more plunger release teeth 1145 can project radially outward from the outer surface 1142 of the hollow body 1124. The one or more plunger release teeth 1145 are separated from each other by portions of the outer surface 1142 of the hollow body 1124, thereby forming grooves between adjacent plunger release teeth 1145. In embodiments providing more than two plunger release teeth 1145, the plunger release teeth 1145 may be uniformly spaced apart from each other. In some embodiments, the plunger release teeth 1145 may have unequal angular extensions and / or unequal angular spacing. The radial spacing of the plunger release teeth 1145 may be selected to correspond to the spacing between one or more release tabs 380 on the plunger 326. The distal end 1147 of each plunger release tooth 1145 may have a pointed end 1149 configured to guide one or more release tabs 380 on the plunger 326 from its orientation during engagement of the plunger 326 with the plunger engagement sleeve 1114. As described herein, one or more plunger release teeth 1145 are configured to interact with one or more release tabs 380 on the plunger 326 to achieve release of the plunger 326 from the piston as the plunger 326 rotates about its longitudinal axis 334, for example, due to rotation of the syringe 300.

[0330] refer to Figure 27BA portion of the inner surface 1128 of the central opening 1116 at its distal end may have a chamfer 1130, such that the inner diameter of the opening 1116 narrows in a direction from the distal end 1126 of the hollow body 1124 toward the proximal portion or proximal end 1132. In some embodiments, the chamfer 1130 may be configured to deflect at least a portion of at least one retaining member 368 associated with the plunger 326 in a radially inward direction during the connection of the plunger 326 to the distal portion or distal end 1126 of the plunger engagement sleeve 1114. In other embodiments, the chamfer 1130 may define a clearance space for at least a portion (e.g., a snap 374) of at least one retaining member 368 during the connection of the plunger 326 to the plunger engagement sleeve 1114. The inner surface 1128 of the central opening 1116 may have an inclined inner diameter that decreases in the direction from the distal end 1126 of the plunger engagement sleeve 1114 toward the proximal end of the plunger engagement sleeve 1114. For example, the opening 1116 may have a first inner diameter and a second diameter, the first inner diameter being proximal to the ramp 1130 and the second diameter being smaller than the first diameter distal to the ramp 1130. The inner surface 1128 of the central opening 1116 proximal to the ramp 1130 may be generally cylindrical. In other embodiments, one or both portions of the inner surface 1128 before and after the ramp 1130 may be slightly inclined at an angle in the same direction as the ramp 1130.

[0331] refer to Figure 26 and Figure 28 A plunger release sleeve 1158 surrounds at least a portion of a plunger engagement sleeve 1114. In some embodiments, the plunger release sleeve 1158 has a hollow body 1159 having an inner cavity 1161 configured to receive a proximal or proximal portion 1132 of the plunger engagement sleeve 1114. In some embodiments, the plunger release sleeve 1158 has a cylindrical sidewall 1160 having an opening 1162 extending therethrough. The opening 1162 may have a longitudinal surface 1163 substantially parallel to the longitudinal axis 1164 of the plunger release sleeve 1158, and an inclined surface 1166 adjacent to the longitudinal surface 1163 and inclined downward relative to the longitudinal axis 1164 of the plunger release sleeve 1158 in a direction from the distal end 1168 toward the proximal end 1170. As described herein, the longitudinal surface 1163 is configured to guide the guide pin 1139 associated with the plunger engagement post 1118 during movement of the plunger engagement post 1118 in the longitudinal direction along the longitudinal axis 1120 of the piston 1100, while the inclined surface 1164 is configured to guide the guide pin 1139 to move the plunger engagement post 1118 during rotational movement of the plunger 326 relative to the piston 1100, such as during removal of the plunger 326 from the piston 1100.

[0332] refer to Figure 29 The plunger engagement mechanism 1112 also includes a housing 1146 for receiving the actuator 1122. The housing 1146 has a proximal portion 1152 connected to the distal portion 1154. In some embodiments, the distal portion 1154 may have a smaller outer diameter than the proximal portion 1152, such that a boss 1156 is defined at the transition between the proximal and distal portions 1154. In some embodiments, the boss 1156 may be configured to support the proximal end of a biasing member 1196 configured to release the plunger 326 from the piston engagement mechanism 1112 during disengagement of the plunger 326 from the piston 1100. In some embodiments, the biasing member 1196 may be a torsion spring having a first end connected to the housing 1146 and a second end connected to the plunger release sleeve 1158.

[0333] refer to Figure 26 The plunger engagement sleeve 1114 and the plunger release sleeve 1158 are fixed and do not rotate relative to each other, but both can rotate relative to the plunger release pin 1118 about the longitudinal piston axis 1120 between a first position and a second position, as referenced herein. Figures 30A-30D In some embodiments, the plunger engagement sleeve 1114 and the plunger release sleeve 1158 can rotate clockwise and counterclockwise, or one of clockwise and counterclockwise. Due to the rotational movement of the plunger 326 about the longitudinal piston axis 1120, the plunger engagement sleeve 1114 and the plunger release sleeve 1158 can rotate from a first position to a second position. For example, due to the interaction between the release tab 380 on the plunger 326 and the toothed portion 1144 on the piston engagement sleeve 1114, the plunger engagement sleeve 1114 and the plunger release sleeve 1158 can rotate about the longitudinal axis 1120. The biasing member 1196 can be configured to bias the plunger engagement sleeve 1114 and the plunger release sleeve 1158 to the first position. In this way, as the plunger engagement sleeve 1114 and the plunger release sleeve 1158 rotate from the first position toward the second position, the biasing member 1196 builds up potential energy therein, which is then used to help the plunger engagement sleeve 1114 and the plunger release sleeve 1158 return toward the first position.

[0334] refer to Figure 29The diagram shows a plunger engagement post 1118 separate from the plunger engagement mechanism 1112. The plunger engagement post 1118 has a shaft 1172 with a proximal end 1176 and a distal end 1174. The proximal end 1176 of the shaft 1172 is connected to a housing 1146. The distal end 1174 of the shaft 1172 has a tapered or rounded end face 1178 configured to contact at least one retaining member 368 on the plunger 326, so as to flexibly deflect the at least one retaining member 368 radially outward as it passes the end face 1178. Seal 1180 ( Figure 26 It can be located at the proximal end 1176 to seal the inner surface 1128 of the plunger engagement sleeve 1114. The seal 1180 can be an O-ring seal.

[0335] The plunger engagement post 1118 also includes a guide pin 1139 configured to guide movement of the plunger engagement post 1118 relative to the plunger engagement sleeve 1112 and the plunger release sleeve 1158. In some embodiments, the guide pin 1139 extends through the housing 1146 and is arranged substantially perpendicular to the longitudinal axis 1120 of the plunger engagement post 1118.

[0336] The plunger engagement post 1118 has a locking groove 1127, which forms a latch 374 for receiving at least one locking member 368 of the plunger 326. The end face 1178 can be shaped to deflect at least one retaining member 368 radially outward due to contact between the latch 374 and the outer surface of the end face 1178. In this way, distal movement of the piston 1100 relative to the plunger 326 causes at least one retaining member 368 to deflect radially outward due to contact between the latch 374 and the circular or conical outer surface of the end face 1178.

[0337] The plunger engagement post 1118 has sensing elements 1105, such as a pin 1107 and a sensor 1109. The pin 1107 has a proximal end 1113 configured to contact the sensor 1109 when the distal end 1117 of the pin 1107 is pushed proximally, for example, due to contact between the plunger 326 and the distal end 1117 of the pin 1107. The pin 1107 may extend along the longitudinal axis 1120 of the piston 1100 and may protrude through at least a portion of the piston head 1106. The pin 1107 is operable to sense contact with a surface (e.g., the inner surface of the plunger 326) and to send one or more signals to the controller 200 of the fluid injector to control the movement of the piston 1100 based on the sensed condition. For example, initial contact between the distal end 1117 of the pin 1107 and the plunger 326 may cause the pin 1107 to retract proximally, thereby activating the sensor 1109. Sensor 1109 can be operatively connected to controller 200, which controls the drive mechanism of piston 1100 such that when sensor 1109 is activated by pin 1107, sensor 1109 controls the movement of the drive mechanism. For example, the drive mechanism can stop or slow down from a first rate to a second, slower rate. Pin 1107 can be biased to its distal position by spring 1111. A seal 1119 can be provided between pin 1107 and plunger engagement post 1118 to prevent fluid ingress.

[0338] Continue to refer to Figure 29 One or more lamps 1173 may be disposed on a printed circuit board 1175 on the base of the plunger engagement post 1118. As described herein, one or more lamps 1173 may be configured to illuminate at least a portion of the plunger 326 and the plunger engagement sleeve 1114.

[0339] The structure of the plunger 326 and piston 1100 has been described according to a non-limiting embodiment of this disclosure, and will now be referred to... Figures 30A-30D Describe the engagement method of plunger 326 and piston 1100. Figures 31A-31D The plunger engagement mechanism 1112 is shown during the various stages of plunger 326 disengaging from piston 1100.

[0340] Figure 30AA piston 1100 is shown with its plunger engagement mechanism 1112 in a disengaged position or state before being connected to the plunger 326. In some embodiments, the default state of the plunger engagement mechanism 1112 may be the engaged position or state. In other embodiments, the default state of the plunger engagement mechanism 1112 may be the disengaged position or state. To connect the plunger 326 to the piston 1100, a syringe 300 is first connected to an injector. During the connection of the syringe 300 to the injector, the piston 1100 is retracted into the syringe housing. After the syringe 300 is connected to the injector, the piston 1100 may be advanced distally toward the plunger 326 within the orifice of the syringe 300.

[0341] refer to Figure 30A Operator 1122 (e.g.) Figure 26 (As shown) to its disengaged position or state, wherein the plunger engagement pin 1118 is positioned in its distal position. Distal movement of the plunger engagement pin 1118 opens a receiving space 1115 between the plunger engagement sleeve 1114 and the plunger engagement pin 1118 to allow one or more retaining members 368 of the plunger 326 to be inserted into the receiving space 1115. The pin 1107 is in its distal position, while the guide pin 1139 is located in the opening 1162 on the plunger release sleeve 1158 (…). Figure 28 At the distal end 1151 of the longitudinal surface 1163.

[0342] refer to Figure 30B The piston 1100 moves axially toward the distal side of the plunger 326 (indicated by arrow A1). In some embodiments, a controller 200 of the injector can be used. Figure 2 The drive mechanism 402, operated by the piston, propels the piston 1100 distally. In other embodiments, the piston can be manually moved in the distal direction. The piston 1100 is axially advanced in the distal direction such that at least one retaining member 368 of the plunger 326 is received within the central opening 1116 of the plunger engagement sleeve 1114. As the piston 1100 advances distally toward the plunger 326, at least a portion of one or more retaining members 368 on the plunger 326 contacts the tapered end face 1178 of the plunger engagement post 1118, which flexibly deflects the retaining member 368 in a radially outward direction. For example, because the latch 374 protrudes radially inward relative to the second end of each retaining member 368, the latch 374 contacts the tapered surface 1178 of the plunger engagement post 1118, which causes the retaining member 368 to deflect in a radially outward direction. In embodiments with multiple retaining members 368, each retaining member 368 deflects in a radially outward direction.

[0343] refer to Figure 30CDuring the continued axial movement of the piston 1100 in the distal direction, the locking member 328 is positioned such that the latch 374 can be deflected into the locking recess 1127 of the piston engagement post 1118. After the latch 374 is positioned in the locking recess 1127, at least one retaining member 368 can be resiliently deflected in a radially inward direction, and the retaining member 328 can straddle the ramp 1130 on the inner surface 1128 of the central opening 1116 and enter into the second diameter of the inner surface 1128. When at least one retaining member 368 is in Figure 30C In the indicated position, plunger 326 is not locked into engagement with piston 1100 because at least one retaining member 368 can be deflected radially outward as piston 1100 moves proximally or plunger 326 moves distally (e.g., due to removal of the syringe from the injector), and latch 374 can be disengaged from locking recess 1127. With plunger 326 engaged with piston 1100, one or more release tabs 380 on plunger 326 align with the toothed portion 1144 on the outer surface 1142 of plunger engagement sleeve 1114. Figure 30A The pin 1107 of the sensing member 1105 moves axially in the proximal direction due to contact with the plunger 326, so that the proximal end 1113 of the pin 1107 can be detected by the sensor 1109, thereby sending a signal to the controller 200 to stop the piston 1100 from moving further distally.

[0344] refer to Figure 30D Operating actuator 1122 ( Figure 26 The plunger engaging post 1118 is moved from a disengaged position or state to an engaged position or state in the proximal direction as indicated by arrow B1. The distal movement of the plunger engaging post 1118 closes the receiving space 1115 between the plunger engaging sleeve 1114 and the plunger engaging post 1118, locking the latch 374 within the locking groove 1127 to prevent one or more retaining members 368 of the plunger 326 from disengaging and moving out of the receiving space 1115. Once the plunger engaging post 1118 is moved to the engaged position or state, at least one retaining member 368 of the plunger 326 (including the latch 374) is captured between the plunger engaging sleeve 1114 and the plunger engaging post 1118, such that axial movement of the piston 1100 causes a corresponding axial movement of the plunger 326 within the syringe barrel. As the plunger engaging post 1118 moves proximally, the guide pin 1139 extends proximally from the opening 1162 on the plunger release sleeve 1158. Figure 28 The distal end 1151 of the longitudinal surface 1163 is axially moved to the proximal end 1153.

[0345] The piston 1100 and the connected plunger 326 can then reciprocate within the barrel 318 of the syringe 300. In some embodiments, the piston 1100 can be advanced distally to deliver fluid from the syringe 300, or advanced proximally using a drive mechanism 402 operated by the controller 200 to fill the syringe 300 with fluid. Figure 2 ).

[0346] refer to Figures 31A-31D To unlock the syringe 300 from the syringe port of the injector and disengage the plunger 326 from the piston 1100, the syringe 300 may be positioned relative to the syringe port about the longitudinal axis 315 of the syringe. Figure 5B Rotation clockwise or counterclockwise. Because the plungers 326 do not rotate substantially within the syringe barrel 318 due to frictional contact between them, rotation of the syringe 300 also causes the plungers 326 to rotate relative to the piston 1100 about the longitudinal piston axis 1120. As one or more release tabs 380 on the plunger 326 align with the plunger release teeth 1145 on the toothed portion 1144 of the plunger engagement sleeve 1114, rotation of the plunger 326 also causes the plunger engagement sleeve 1114 and the plunger release sleeve 1158 to rotate relative to the plunger engagement pin 1118 from a first position to a second position. Because the guide pin 1139 on the plunger engagement post 1118 is received within the opening 1162 on the plunger release sleeve 1158, and because the plunger engagement post 1118 does not rotate about the longitudinal piston axis 1120, the rotation of the plunger engagement sleeve 1114 causes the guide pin 439 to follow the inclined surface 1166 of the plunger release sleeve 1158 (see also...). Figure 28 )from Figure 30D The first position shown is guided to Figure 31A The second position shown is (e.g., from the proximal end of the inclined surface 1166 to the distal end of the inclined surface 1166). Furthermore, the rotation of the plunger engagement sleeve 1114 about the longitudinal piston axis 1120 establishes potential energy in the biasing member 1196.

[0347] Continue to refer to Figure 31A The movement of guide pin 1139 along the inclined surface 1166 of plunger release sleeve 1158 causes plunger engagement post 1118 to move axially from the engaged position or state to the disengaged position or state in the distal direction of arrow C1. The distal movement of plunger engagement post 1118 opens the receiving space 1115 between plunger engagement sleeve 1114 and plunger engagement post 1118 to allow one or more retaining members 368 of plunger 326 to move distally from the receiving space 1115 (see...). Figure 31B ).

[0348] When the plunger engagement mechanism 1112 is in the disengaged position or state, the syringe 300 can be pulled distally or the piston 1100 can be retracted proximally to remove the plunger 326 from the piston 1100. During this relative movement of the piston 326 and the plunger 1100 in a direction away from each other, the latch 374 of at least one of the retaining members 368 engages the plunger engagement post 1118 distally in the locking groove 1127, such that each retaining member 368 is flexibly deflected in a radially outward direction. Figure 31C The continuous movement of piston 1000 relative to plunger 326 allows plunger 326 to be freely pulled away from piston 1100, as... Figure 31D As shown, this allows the syringe 300 to be removed from the injector port.

[0349] refer to Figure 31D After the plunger 326 is removed from the piston 1100, the plunger engagement sleeve 1114 and the plunger engagement pin 1118 automatically rotate from the second position to the first position about the longitudinal axis 1120 due to the restoring force provided by the biasing member 1196. As the plunger engagement sleeve 1114 and the plunger engagement pin 1118 move to the first position, the guide pin 1129 is guided along the top surface 1179 within the opening 1162 of the plunger release sleeve 1158 due to the restoring force provided by the biasing member 1196.

[0350] Next, refer to Figure 32-35B This illustrates an injector assembly 2000 according to another aspect of the present disclosure. The injector assembly 2000 includes a housing 2002 that houses an automated or powered fluid injector. The fluid injector is adapted to engage and actuate one or more syringes, wherein each syringe can be independently filled with a medical fluid, such as contrast media, saline solution, or any desired medical fluid, as referenced above. Figure 1 or Figure 3 Similar descriptions exist. For example, the injector housing 2002 is configured to hold syringes 2006a, 2006b, each containing medical fluid.

[0351] As is known in the art, syringes 2006a and 2006b are typically made of polypropylene or similar materials with a specific minimum wall thickness. During certain procedures, such as angiography imaging, syringes 2006a and 2006b may be subjected to pressures up to 1200 psi when used to inject fluid into a patient; therefore, the wall thickness and elasticity of the syringe are important to ensure that the syringe does not expand radially, rupture, detach from the injector, or leak. To further prevent possible radial expansion of syringes 2006a and 2006b during high-pressure injection, corresponding pressure sleeves 2004a and 2004b are used to seal and retain syringes 2006a and 2006b. Pressure sleeves 2004a and 2004b are used to limit the radial expansion of the syringe barrel. That is, during the injection process, the outer wall of syringes 2006a and 2006b expands against the inner wall of the corresponding pressure sleeves 2004a and 2004b, thereby limiting the radial expansion of the outer wall of the syringe, which would otherwise lead to rupture or leakage.

[0352] Pressure sleeves 2004a and 2004b may be individual components or may be formed as a single integral design. Pressure sleeves 2004a and 2004b are held on the injector head of housing 2002 via corresponding attachment interfaces 2010a and 2010b. A suitable non-limiting example of a pressure sleeve including syringe holding features for a CV injection process is described in international PCT application PCT / US2020 / 049885, which is incorporated herein by reference.

[0353] In addition to the radial forces acting on syringes 2006a, 2006b and pressure jackets 2004a, 2004b, significant axial movement may also occur during high-pressure injection due to the elastic properties of the structural components that suppress the injection of syringes 2006a, 2006b. For example, a single 150 ml syringe with a cross-sectional area of ​​1.6 square inches may require a force of 2400 psi to suppress forward movement of the syringe at 1200 psi. To limit this axial movement of syringes 2006a, 2006b, corresponding caps 2008a, 2008b can be used to partially enclose the distal ends of syringes 2006a, 2006b and retain syringes 2006a, 2006b within the injector and pressure jackets 2004a, 2004b during high-pressure injection. The caps 2008a and 2008b may have openings formed at their distal ends to allow at least a portion of the necks 2009a and 2009b of the syringes 2006a and 2006b to protrude therefrom, thereby allowing the syringes 2006a and 2006b to be connected to a fluid line leading to the patient.

[0354] Due to the axial forces applied to syringes 2006a and 2006b, the attachment interfaces between pressure sheaths 2004a and 2004b and housing 2002, and / or between caps 2008a and 2008b and pressure sheaths 2004a and 2004b, are expected to have sufficient strength to resist axial movement or accidental separation. However, while strength is critical, it is also important for the operator to be able to easily remove caps 2008a and 2008b and / or pressure sheaths 2004a and 2004b, as syringes 2006a and 2006b need to be removed or inserted. Therefore, the connection interface between pressure sheaths 2004a and 2004b and housing 2002 is expected to be sufficiently secure while allowing for easy attachment and removal. Similarly, the connection interface between caps 2008a and 2008b and pressure sheaths 2004a and 2004b is expected to be secure, while also allowing for easy attachment and removal.

[0355] To achieve these desired properties, the attachment interfaces 2010a and 2010b of the pressure jackets 2004a and 2004b may have features related to... Figure 6-8C The connector features shown are similar to those of the plunger 326, while Figure 32 The attachment interfaces 2020a and 2020b of the housing 2002 shown may have the same characteristics as the reference. Figure 9-31D The connector features are similar to those shown and described in various embodiments of the plunger engagement mechanism. That is, the attachment interfaces 2010a, 2010b may include one or more resilient flexible retaining members with snap-fit ​​mechanisms, similar to those described in the reference series. Figure 6-8C The resilient flexible retaining member 368 and the snap-fit ​​374 shown and described are circumferentially positioned around an opening on the proximal end of the pressure sheaths 2004a, 2004b. Similarly, the attachment interfaces 2020a, 2020b of the housing 2002 may include one or more features similar to those described above. Figure 9-31D The plunger engagement sleeve and plunger engagement post shown and described.

[0356] In operation, attachment interfaces 2010a, 2010b and 2020a, 2020b are configured to interact in a manner substantially similar to the interaction between plunger 326 and plunger engagement mechanism, as per [reference to...]. Figure 9-31DDetailed illustration and description are provided. Specifically, when attachment interfaces 2010a, 2010b are axially aligned with their respective attachment interfaces 2020a, 2020b, the respective attachment interfaces 2010a, 2010b and 2020a, 2020b interact to secure pressure sleeves 2004a, 2004b to the housing 2002. One or more retaining members within attachment interfaces 2020a, 2020b (which in some embodiments may project inwardly from the distal end of attachment interfaces 2020a, 2020b) are then configured to engage the lip of an engagement ring within each attachment interface 2010a, 2010b to securely attach pressure sleeves 2004a, 2004b to the housing 2002.

[0357] To detach pressure sleeves 2004a and 2004b from housing 2002, pressure sleeves 2004a and 2004b can rotate relative to housing 2002 (together or separately). Rotation of pressure sleeves 2004a and 2004b allows attachment interfaces 2010a and 2010b to interact with attachment interfaces 2020a and 2020b, similar to the above description regarding... Figure 9-31D The aforementioned situation. This interaction is used to push at least one retaining member radially outward or inward, such that at least one retaining member no longer engages with the corresponding structure on the attachment interfaces 2010a, 2010b, at which point the pressure sleeves 2004a, 2004b can be axially separated from the housing 2002.

[0358] Alternatively, during insertion, the proximal ends of the bodies of syringes 2006a and 2006b within the pressure sleeves 2004a and 2004b can function similarly to plunger engagement posts, locking the corresponding flexible retaining member of the pressure sleeve in the corresponding locking groove or lip in the pressure sleeve port on the injector. For example, after completing the injection procedure, removing syringes 2006a and 2006b from the pressure sleeves 2004a and 2004b disengages the flexible retaining member of the pressure sleeve from the corresponding locking groove or lip in the pressure sleeve port, thereby allowing the pressure sleeve to be removed from the port.

[0359] According to another aspect of this disclosure, the structural details of the aforementioned attachment interfaces 2010a, 2010b and 2020a, 2020b can be reversed. That is, attachment interfaces 2010a, 2010b of the pressure sleeves 2004a, 2004b may include, for example, at least one retaining member and corresponding features, while attachment interfaces 2020a, 2020b may include, as referred to herein... Figure 9-31D The characteristics of the described plunger engagement mechanism.

[0360] Next, refer to Figure 34 , Figure 35A and Figure 35BThis illustrates an alternative aspect of the present disclosure. As stated above regarding... Figures 32-33 As described, caps 2008a and 2008b are typically disposed around the distal ends of the corresponding pressure sleeves 2004a and 2004b to axially retain the corresponding syringes therein. For example... Figure 35A As shown, the cap 2008 may have an attachment interface 2014 for attachment to a pressure sheath, and an opening 2016 formed therein to allow a portion of the distal end of the syringe to extend through.

[0361] To achieve a secure connection between the pressure sleeves 2004a, 2004b and the covers 2008a, 2008b, it is advantageous to construct corresponding interfaces between the pressure sleeves 2004a, 2004b and the covers 2008a, 2008b, such that they are configured in various embodiments substantially similar to the plunger 326. Figure 9-31D The various embodiments of the plunger engagement mechanism are shown and described in detail in the manner in which they interact. For example... Figure 33 As shown, pressure sleeves 2004a and 2004b may have corresponding attachment interfaces 2012a and 2012b at their distal ends for engaging with corresponding covers 2008a and 2008b. Attachment interfaces 2012a and 2012b may include, as per [reference to...] Figure 9-31D The one or more plunger engagement mechanisms shown and described. Similarly, Figure 35A The attachment interface 2014 of the cover 2008 shown may include one or more resiliently deflectable retaining members 368 and corresponding snap fasteners 374, as shown in reference. Figure 6-8C As shown and described, the engagement between the attachment interfaces 2012a, 2012b of the pressure sleeves 2004a, 2004b and the attachment interface 2014 of the corresponding cover 2008 can be as described above. Figure 9-31D The engagement between the plunger 326 and the plunger engagement mechanism is the same or substantially similar. In this way, the covers 2008a, 2008b can be securely engaged with the distal ends of the pressure sleeves 2004a, 2004b, and can be easily disengaged from the distal ends of the pressure sleeves 2004a, 2004b.

[0362] As an alternative to the 2008 cap, which is separate from and surrounds part of the syringe, Figure 35B A syringe assembly 2030 is shown, having a syringe body 2032 with a cap 2036 integrated therewith. That is, the cap 2036 can be molded or formed directly with the syringe body 2032. A neck 2034 extends from the distal surface of the cap 2036 to provide a connection point for a fluid line leading to the patient. (Similar to...) Figure 35A The attachment interface 2014 is shown and described, and the attachment interface 2038 is formed in the cover 2038. Similar to the above regarding... Figure 32 and 35A As described above, attachment interface 2038 may include features that interact with one of the corresponding attachment interfaces 2012a, 2012a of pressure sheaths 2004a, 2004b. Similarly, engagement between attachment interfaces 2012a, 2012b of pressure sheaths 2004a, 2004b and attachment interface 2038 of the corresponding syringe assembly 2030 may be as described above regarding… Figure 9-31D The same or substantially similar.

[0363] According to another aspect of this disclosure, the structural details of the aforementioned attachment interfaces 2012a, 2012b, and 2014 can be reversed. That is, the attachment interfaces 2012a and 2012b of the pressure sleeves 2004a and 2004b may include, for example, at least one retaining member and corresponding features, while the attachment interface 2014 of each cover 2008 may include features consistent with those described herein. Figure 9-31D The corresponding features associated with the described plunger engagement mechanism. Similarly, the structural details of the aforementioned attachment interfaces 2012a, 2012b, and 2038 can be reversed.

[0364] Although shown and described as integrated with pressure sleeves 2004a and 2004b, one or both attachment ports 2010a, 2010b and 2012a, 2012b of pressure sleeves 2004a and 2004b may optionally be constituted by separate components that can be attached to the proximal or distal end of pressure sleeves 2004a and 2004b. In this way, conventional pressure sleeves can be adapted to one or more separate attachment ports so that the pressure sleeve can be securely engaged with a suitably fitted housing (similar to the cap of cap 2008) and / or a syringe assembly with an integrated cap (similar to the syringe assembly 2030 described above).

[0365] While this disclosure has been described in detail based on embodiments currently considered most practical and preferred for illustrative purposes, it should be understood that such details are for this purpose only, and that this disclosure is not limited to the disclosed embodiments, but rather is intended to cover modifications and equivalent arrangements. For example, it should be understood that this disclosure contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. A plunger for use with a syringe, the plunger comprising: A plunger body that defines a central longitudinal axis and has a proximal end, a distal end, and a circumferential sidewall connecting the proximal end and the distal end; and At least one retaining member, said at least one retaining member being associated with and extending proximally from said plunger body, said at least one retaining member comprising: The first end is connected to the plunger body; The second end is close to the first end and radially elastically deflectable relative to the first end; and At least one latch on the second end, Wherein, the at least one retaining member has an outer surface configured to engage a plunger engagement sleeve of a plunger engagement mechanism on the piston of the fluid injector system when the plunger is in a locked state with the piston. Wherein, the at least one retaining member has an inner surface configured to engage a plunger engagement post of the plunger engagement mechanism when the plunger is in the locked state with the piston. Wherein, the at least one latch is configured to securely engage a locking feature on one of the plunger engagement sleeve and the plunger engagement post when the plunger is in the locked state with the piston, to prevent axial movement of the plunger relative to the piston. Wherein, the at least one latch has a rounded or angled first proximal surface at its proximal end and a rounded or angled second distal surface at its distal end; the rounded or angled first proximal surface is used to flexibly engage the distal end of the locking feature on one of the plunger engagement sleeve and the plunger engagement post during engagement of the plunger with the piston; the rounded or angled second distal surface is used to flexibly engage the proximal end of the locking feature on one of the plunger engagement sleeve and the plunger engagement post during disengagement of the plunger from the piston; and In the unlocked state of the plunger engagement mechanism, the rounded or angled first proximal surface and the rounded or angled second distal surface of at least one latch are configured to cause the second end of the at least one retaining member to radially deflect due to the bending interaction of the at least one latch with the locking feature on one of the plunger engagement sleeve and the plunger engagement post when the piston moves axially relative to the plunger.

2. The plunger according to claim 1, wherein, The at least one retaining member includes a plurality of retaining members spaced apart around the central longitudinal axis.

3. The plunger according to claim 2, wherein, The plurality of retaining members are spaced apart at equal intervals around the central longitudinal axis.

4. The plunger according to any one of claims 1 to 3, wherein, The at least one retaining member extends proximally in a direction parallel to the central longitudinal axis.

5. The plunger according to any one of claims 1 to 4, wherein, The at least one retaining member is linearly adjacent between the first end and the second end.

6. The plunger according to any one of claims 1 to 5, wherein, The plunger is configured to engage the plunger engagement mechanism regardless of the angular orientation of the plunger relative to the piston of the fluid injector system.

7. The plunger according to any one of claims 1 to 6, wherein, The at least one latch protrudes radially inward from the inner surface of the at least one retaining member in a direction toward the central longitudinal axis.

8. The plunger according to any one of claims 1 to 7, wherein, The at least one latch protrudes radially outward from the outer surface of the at least one retaining member in a direction away from the central longitudinal axis.

9. The plunger according to any one of claims 1 to 8, wherein, The at least one snap-fit ​​defines a locking recess for receiving at least a portion of the plunger engagement mechanism when the plunger is connected to the piston.

10. The plunger according to any one of claims 1 to 9, wherein, The at least one latch protrudes radially inward from the inner surface of the at least one retaining member in a direction toward the central longitudinal axis, and wherein the at least one latch is configured to be received within the locking feature when the plunger is in a locked state with the piston, the locking feature being shaped as a locking groove protruding radially inward from the outer surface of the plunger engagement post.

11. The plunger according to any one of claims 1 to 10, wherein, The plunger body has a conical portion at the distal end and a cylindrical portion at the proximal end.

12. The plunger according to claim 11, wherein, The at least one retaining member protrudes proximally from the inner surface of the conical portion.

13. The plunger of claim 11 or 12 further comprises a plurality of release tabs projecting radially inward from the inner surface of the cylindrical portion or proximal to the inner surface of the cylindrical portion, each of the plurality of release tabs being configured to interact with the plunger engagement sleeve to release the plunger from the piston as the plunger rotates about the central longitudinal axis.

14. The plunger according to claim 13, wherein, Each of the plurality of release tabs has a sharp guiding surface at its proximal end.

15. The plunger according to claim 1, wherein, When the plunger is in a locked state with the piston, the at least one latch protrudes radially outward from the outer surface of the at least one retaining member in a direction away from the central longitudinal axis, and wherein the at least one latch is configured to be received within the locking feature, the locking feature being shaped as a locking groove protruding radially outward from the inner surface of the plunger engagement post.

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