Medical injector meter pump with interlocking

Abstract

A metering pump for a medical syringe includes a housing, a sleeve received at least partially within the housing, a piston received at least partially within the sleeve, and an interlock. The piston has a first position in which the chamber has a first volume and a second position in which the chamber has a second volume, where the first volume is greater than the second volume. The sleeve has a first rotational position in which the inlet is in fluid communication with the chamber, a second rotational position in which the outlet is in fluid communication with the chamber, and a third rotational position in which the inlet and the outlet are isolated from the chamber. The interlock includes a resilient member positioned on one of the sleeve and the housing and a protrusion positioned on the other of the sleeve and the housing, where engagement between the resilient member and the protrusion is configured to limit movement of the sleeve until the sleeve overcomes a predetermined torque value.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 17 / 860,506, filed on July 8, 2022, entitled “Medical Injector Metering Pumpwith Interlock,” the entire disclosure of which is incorporated herein by reference in its entirety.

[0003] Background of the Invention

[0004] Field of the Invention

[0005] The present disclosure relates to an interlock for a medical syringe metering pump.

[0006] Description of Related Technology

[0007] The benefit of a wearable medical device, such as an auto-injector, is to provide treatment to a patient at a location remote from a clinical facility and / or while being worn separately under the patient's clothing. The wearable medical device can be applied to the patient's skin and configured to automatically deliver a dose of a pharmaceutical composition within a predetermined time period after the wearable medical device is applied to the patient's skin (such as after a 27-hour delay). After the device delivers the pharmaceutical composition to the patient, the patient can then remove and dispose of the device. Summary of the invention

[0008] In one aspect or embodiment, a metering pump for a medical syringe including a reservoir and a cannula includes a housing, a sleeve at least partially received in the housing, a piston at least partially received in the sleeve, and an interlock. The piston and the sleeve define a chamber, wherein the piston has a first position and a second position, in which the chamber has a first volume, in which the chamber has a second volume, and wherein the first volume is greater than the second volume. The sleeve has a first rotational position, a second rotational position, and a third rotational position, in which the inlet is in fluid communication with the chamber, in which the outlet is in fluid communication with the chamber, and in which the inlet and the outlet are isolated from the chamber in the third rotational position. The interlock includes an elastic member and a protrusion, the elastic member is positioned on one of the sleeve and the housing, the protrusion is positioned on the other of the sleeve and the housing, wherein the engagement between the elastic member and the protrusion is configured to limit the movement of the sleeve until the sleeve overcomes a predetermined torque value.

[0009] The resilient member may be positioned on the housing and the protrusion may be positioned on the sleeve. When the sleeve rotates relative to the housing, the resilient member may be elastically deformed by the protrusion. The resilient member may extend radially inwardly from the housing and the protrusion may extend radially outwardly from the sleeve, wherein when the sleeve rotates relative to the housing, the resilient member is compressed by the protrusion. The resilient member may be overmolded onto the housing.

[0010] The piston can be configured to rotate and move axially relative to the housing and the sleeve, wherein the piston is configured to rotate relative to the housing together with the sleeve. The piston can be connected to the sleeve via a pin, and the pin is received in the spiral groove defined by the sleeve. The inlet can be configured to be communicated with the reservoir fluid of the medical syringe, wherein the outlet is configured to be communicated with the sleeve fluid of the medical syringe. The rotation of the piston in a first rotational direction can be configured to pump fluid in the chamber and move the sleeve from the first rotational position to the second rotational position, and the rotation of the piston in a second rotational direction can be configured to pump the fluid in the chamber and move the sleeve from the second rotational position to the first rotational position, wherein the second rotational direction is opposite to the first rotational direction.

[0011] The predetermined torque value can be 5 millinewton meters to 15 millinewton meters. The predetermined torque value can be 5 millinewton meters to 9 millinewton meters. The interlocking piece can be configured to generate a maximum torque while maintaining the fluid communication between the chamber and the outlet, and the maximum torque is at least equal to the torque difference between the maximum operating pressure and the minimum operating pressure of the metering pump. The torque curve (torque profile) provided by the interlocking piece can be symmetrical when the sleeve moves between the first rotational position and the second rotational position. The maximum torque provided by the interlocking piece when the sleeve moves from the first rotational position to the second rotational position can be less than the maximum torque provided by the interlocking piece when the sleeve moves from the second rotational position to the first rotational position. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other features and advantages of the present disclosure and the manner in which they are achieved will become more apparent, and the present disclosure itself will be better understood, by referring to the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, in which:

[0013] FIG1 is a perspective view of a conventional interlocking member and metering pump assembly;

[0014] FIG2 is a perspective view of the interlock and metering pump assembly of FIG1 , illustrating the ready-to-dispense stage of operation;

[0015] FIG3 is a perspective view of the interlock and metering pump assembly of FIG1 , showing the ready-to-pump stage of operation;

[0016] FIG4 is a schematic diagram of a conventional medical syringe;

[0017] Figure 5 is a perspective view of a metering pump assembly with interlocking parts according to one aspect or embodiment of the present application;

[0018] Figure 6 yes Figure 5 An exploded view of the components;

[0019] Figure 7 yes Figure 5 a cross-sectional view of a housing and a sleeve of an assembly of; and

[0020] Figure 8 yes Figure 5 A cross-sectional view of the housing and sleeve of the assembly.

[0021] Corresponding reference numerals indicate corresponding parts throughout the several views.The exemplifications set out herein illustrate exemplary embodiments of the disclosure, and such exemplifications should not be construed as limiting the scope of the disclosure in any way. DETAILED DESCRIPTION

[0022] Spatial or directional terms (such as "left", "right", "inner", "outer", "upper", and "lower", etc.) are not to be considered limiting as the invention can assume various alternative orientations.

[0023] All numbers used in the specification and claims are to be understood as being modified in all cases by the term "about". "About" means a range of plus or minus ten percent of the value recorded. As used in the specification and claims, the singular forms "a", "an", and "the" include plural references unless the context clearly indicates otherwise. The terms "first", "second", etc. are not intended to refer to any particular order or sequence, but rather to different conditions, characteristics, or elements. "At least" means "greater than or equal to".

[0024] Referring to Figures 1 to 4, Figures 1 to 4 show a conventional metering pump 10 for a medical syringe or drug delivery device 12. The metering pump 10 is a rotary metering pump described in the international publication document of publication number WO 2015 / 157174, which is incorporated herein by reference in its entirety. The metering pump 10 is configured to be connected to a direct current (DC) motor and a gearbox assembly (not shown) to rotate the sleeve 14 in the housing 16. A spiral groove 18 is provided on the sleeve 14. When the sleeve 14 rotates in one direction and then rotates in the opposite direction, the coupling pin 20 connected to the piston 22 translates along the spiral groove 18 to guide the piston 22 to retract and insert in the sleeve 14, respectively. The sleeve 14 has an end plug 24. When the piston 22 retracts after the suction stroke (as shown in Figure 2) and is therefore ready to be dispensed, two seals 26 located on the corresponding ends of the piston 22 and the end plug 24 and located inside the sleeve 14 define a cavity or chamber 28. The volume of chamber 28 varies depending on the degree of retraction of piston 22. When piston 22 is fully inserted after a dispensing stroke and seals 26 are substantially in contact with each other (as shown in FIG. 3 ) and are therefore ready for aspiration, the volume of chamber 28 is negligible or substantially zero.

[0025] Two ports 30, 32 are provided relative to the housing 16, including an inlet port 30 through which drug can flow from the reservoir 58 (Figure 4) for use in the pump 10 (Figure 4), and an outlet port 32 through which drug that has been drawn into the chamber 28 (for example, by retracting the piston 22 during the aspiration phase of operation) can be reinserted into the chamber 28 through the piston 22 and dispensed from the chamber 28 to, for example, a fluid path leading to the cannula 50 (Figure 4) in the patient.

[0026] 1 to 3, the sleeve 14 includes an orifice (not shown) that is aligned with the outlet port 32 or the inlet port 30 (i.e., depending on the degree of rotation of the sleeve 14, and therefore the degree of translation of the piston 22, to allow the drug in the chamber 28 to flow through the corresponding one of the ports 30, 32). A pump metering device 34 (FIG. 4) such as a sleeve rotation limit switch may be provided, having, for example, an interlock 36 and one or more stops 38 located on the sleeve 14 or the end plug 24 of the sleeve, which cooperate with the interlock 36. The interlock 36 may be mounted to the housing 16 at each end of the housing. The stops 38 at the end face of the sleeve 14 are adjacent to the protrusion 40 of the interlock 36.

[0027] Under certain conditions (such as back pressure), the friction between the piston 22 and the sleeve 14 may be sufficient to rotate the sleeve 14 before the piston 22 and the coupling pin 20 reach either end of the spiral groove 18, which may result in an incomplete volume of liquid pumped per stroke. To prevent this, the interlock 36 prevents the sleeve 14 from rotating until the torque exceeds a predetermined threshold (as shown in FIG. 2 ). This ensures that the piston 22 rotates fully within the sleeve 14 until the coupling pin 20 reaches the end of the spiral groove 18. Once the coupling pin 20 hits the end of the spiral groove 18, further movement generated by the DC motor and gearbox assembly or other type of pump and valve actuator 62 ( FIG. 4 ) increases the torque on the sleeve 14 to exceed the threshold, thereby causing the interlock 36 to flex and allow the stopper 38 to pass the protrusion 40. Upon completion of the rotation of the sleeve 14 so that the sleeve port or orifice is oriented with the cannula or outlet port 32, the stopper 38 moves past the protrusion 40 (shown in FIG. 3 ) in the interlock 36. Another sleeve feature 42 may be provided to engage an electrical switch (e.g., an end stop switch disposed on a printed circuit board and disposed relative to the sleeve 14 and / or end plug 24 to cooperate with the pump metering device 34 (shown in FIG. 4 )).

[0028] 4, the medical syringe 12 may include a metering pump 10 as described above, an electronics subsystem 44 for controlling the operation of components in a fluid subsystem 46 (such as the pump 10), and an insertion mechanism 48 for deploying a cannula 50 for insertion into an infusion site on the patient's skin. A power storage subsystem 52 may include batteries 54, which are used, for example, to provide power to components in the electronics subsystem 44 and components in the fluid subsystem 46. The fluid subsystem 46 may include, for example, an optional filling port 56 for filling a reservoir 58 (e.g., with a drug), although the medical syringe may be optionally shipped from the manufacturer with its reservoir already filled. The fluid subsystem 46 also has a metering subsystem 60, which includes the metering pump 10 and a pump and valve actuator 62.

[0029] As described above, the metering pump 10 can have two ports 30, 32 and associated valve subassemblies that control when fluid enters and leaves the chamber 28 via the respective ports 30, 32. One of these ports is the inlet port 30 through which fluid (such as a liquid drug) flows from a reservoir 58 into the metering pump 10 due to the pump suction or pull stroke. The fluid leaves the chamber 28 of the metering pump 10 through the outlet port 32 due to the pump discharge or push stroke of the metering pump 10 and flows toward the cannula 50 for administration. The pump and valve actuator 62 can be a DC motor and gearbox assembly or other pump drive mechanism for controlling the plunger or piston 22 and other associated pump components (such as the sleeve 14), which can rotate with the translational movement of the piston 22. The microcontroller 64 may be provided with an integrated or separate memory device having computer software instructions to actuate, for example, rotation of the sleeve 14 in a selected direction, translation or axial movement of the piston 22 in the sleeve 14 for aspiration or dispensing stroke, and optionally rotation of the sleeve 14 and piston 22 together during a valve state change, as described in WO 2015 / 157174 cited above. The metering pump 10 and interlock 36 may be the same metering pump and interlock shown and described in International Publication No. WO 2019 / 156848, which is incorporated herein by reference in its entirety.

[0030] The interlock 36 of the metering pump 10 shown in Figures 1 to 3 is formed separately from the housing 16. In particular, the interlock 36 is formed of sheet metal and attached to the housing 16. Due to manufacturing tolerances and other variability, the performance of the interlock 36 may be inconsistent between the suction movement and the dispensing movement, and may also be inconsistent between devices, which may result in different force distributions or force patterns between devices, which makes it more difficult to detect blockages. Separately forming the interlock 36 also requires the manufacture of separate components and subsequent assembly steps.

[0031] refer to Figures 5 to 8 , shows an interlocking member 70 for a metering pump 10 according to one aspect or embodiment of the present application. In one aspect or embodiment, the interlocking member 70 replaces the interlock 36 of the metering pump 10 of Figures 1 to 4, wherein the metering pump 10 operates as described above in other respects.

[0032] In one aspect or embodiment, the metering pump 10 includes a housing 16, a sleeve 14 at least partially received in the housing 16, and a piston 22 at least partially received in the sleeve 14, wherein the piston 22 and the sleeve 14 define a chamber 28. As described above, the piston 22 has a first position and a second position, in which the chamber 28 has a first volume, and in which the chamber 28 has a second volume, wherein the first volume is greater than the second volume. The sleeve 14 has a first rotational position, a second rotational position, and a third rotational position, in which the inlet port 30 is in fluid communication with the chamber 28, in which the outlet port 32 is in fluid communication with the chamber 28, and in which the inlet port 30 and the outlet port 32 are isolated from the chamber 28. The metering pump 10 also includes an interlock 70 having an elastic member 72 positioned on one of the sleeve 14 and the housing 16 and a protrusion 74 positioned on the other of the sleeve 14 and the housing 16. The engagement between the resilient member 72 and the protrusion 74 is configured to limit the movement of the sleeve 14 until the sleeve 14 overcomes the predetermined torque value. Thus, the interlock 70 is configured to ensure that the piston 22 fully completes its linear movement when rotating between the first rotational position and the second rotational position. In other words, the predetermined torque value cannot be too high to prevent the metering pump 10 from operating, nor too low to prematurely rotate the metering pump 10 between the first rotational position and the second rotational position before the piston 22 completes its linear movement.

[0033] refer to Figure 7 and Figure 8 In one aspect or embodiment, the resilient member 72 is positioned on the housing 16 and the protrusion 74 is positioned on the sleeve 14. When the sleeve 14 rotates relative to the housing 16, the resilient member 72 is elastically deformed due to the protrusion 74. In one aspect or embodiment, the protrusion 74 and the resilient member 72 form a cam interference feature. The resilient member 72 extends radially inward from the housing 16, and the protrusion 74 extends radially outward from the sleeve 14, wherein when the sleeve 14 rotates relative to the housing 16, the resilient member 72 is compressed by the protrusion 74. When the protrusion 74 rotates past the resilient member 72, the resilient member 72 is disengaged from the protrusion 74. In one aspect or embodiment, the resilient member 72 is overmolded onto the housing 16, but the resilient member 72 can be formed by other suitable methods and arrangements. The resilient member 72 can be formed of the same material as the housing seal (not shown) formed between the sleeve 14 and the housing 16. The resilient member 72 may be spaced apart from the housing seal to allow the resilient member 72 to deform without compromising the seal between the housing 16 and the sleeve 14 .

[0034] In one aspect or embodiment, the predetermined torque value is 5 millinewtons meters to 15 millinewtons meters. In one aspect or embodiment, the predetermined torque value is 5 millinewtons meters to 9 millinewtons meters.

[0035] In one aspect or embodiment, the interlock 70 is configured to generate a maximum torque while maintaining fluid communication between the chamber 28 and the outlet 32, the maximum torque being at least equal to the torque difference between the maximum operating pressure and the minimum operating pressure of the metering pump 10. The maximum torque can be determined by the shape of the elastic member 72, the shape of the protrusion 74, and / or the elasticity and superelastic material properties of the elastic member 72. In some aspects or embodiments, the torque curve provided by the interlock 70 can be symmetrical when the sleeve 14 moves between the first rotational position and the second rotational position. In some aspects or embodiments, the maximum torque provided by the interlock 70 when the sleeve 14 moves from the first rotational position to the second rotational position is less than the maximum torque provided by the interlock 70 when the sleeve 14 moves from the second rotational position to the first rotational position.

[0036] Reference again Figures 5 to 8 As described above, the piston 22 is configured to rotate and move axially relative to the housing 16 and the sleeve 14, wherein the piston 22 is configured to rotate relative to the housing 16 with the sleeve 14. The piston 22 is connected to the sleeve 14 via the pin 20, which is received in the spiral groove 18 defined by the sleeve 14. The inlet 30 is configured to be in fluid communication with the reservoir 58 of the medical syringe 12, and the outlet 32 ​​is configured to be in fluid communication with the sleeve 50 of the medical syringe 12. As described above, the rotation of the piston 22 in the first rotational direction is configured to draw fluid into the chamber 28 and move the sleeve 14 from the first rotational position to the second rotational position, and the rotation of the piston 22 in the second rotational direction is configured to pump the fluid in the chamber 28 and move the sleeve 14 from the second rotational position to the first rotational position. The second rotational direction is opposite to the first rotational direction.

[0037] Figures 5 to 8 The interlock 70 is configured to be less expensive to manufacture than the interlock 35, requires a fewer number of parts, a fewer number of assembly steps, increases tolerance control, and increases the reliability of the interlock 70. Due to the resilient member 72, the interlock 70 is also quieter during operation of the metering pump 10 than the interlock 35.

[0038] Although for the purpose of illustration, the present invention has been described in detail based on what is currently considered to be the most practical and preferred embodiments, it should be understood that such details are only for this purpose, and the present invention is not limited to the disclosed embodiments, but on the contrary, the present invention is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

1. A metering pump for a medical syringe, the medical syringe comprising a reservoir and a cannula, the metering pump comprising: case; a sleeve at least partially received within the housing; a piston at least partially received within the sleeve, the piston and the sleeve defining a chamber, the piston having a first position and a second position, in the first position the chamber having a first volume, in the second position the chamber having a second volume, the first volume being greater than the second volume, the sleeve having a first rotational position, in the first rotational position the inlet is in fluid communication with the chamber, in the second rotational position the outlet is in fluid communication with the chamber, in the third rotational position the inlet and the outlet are isolated from the chamber; as well as An interlocking piece includes a resilient member and a protrusion, wherein the resilient member is positioned on one of the sleeve and the housing, and the protrusion is positioned on the other of the sleeve and the housing, wherein the engagement between the resilient member and the protrusion is configured to limit the movement of the sleeve until the sleeve overcomes a predetermined torque value.

2. The metering pump according to claim 1, wherein: The elastic member is positioned on the housing, and the protrusion is positioned on the sleeve.

3. The metering pump according to claim 2, wherein: When the sleeve rotates relative to the housing, the elastic member is elastically deformed due to the protrusion.

4. The metering pump according to claim 3, wherein: The resilient member extends radially inwardly from the housing and the protrusion extends radially outwardly from the sleeve, and wherein the resilient member is compressed by the protrusion when the sleeve is rotated relative to the housing.

5. The metering pump according to any one of claims 2 to 4, wherein: The resilient member is overmolded onto the housing.

6. The metering pump according to any one of claims 1 to 5, wherein: The piston is configured to rotate and move axially relative to the housing and the sleeve, and wherein the piston is configured to rotate relative to the housing together with the sleeve.

7. The metering pump according to claim 6, wherein: The piston is connected to the sleeve via a pin received in a helical groove defined by the sleeve.

8. The metering pump according to claim 7, wherein: The inlet is configured to be in fluid communication with the reservoir of the medical syringe, and wherein the outlet is configured to be in fluid communication with the cannula of the medical syringe.

9. The metering pump according to claim 8, wherein: Rotation of the piston in a first rotational direction is configured to draw fluid into the chamber and move the sleeve from the first rotational position to the second rotational position, and wherein rotation of the piston in a second rotational direction is configured to pump fluid in the chamber and move the sleeve from the second rotational position to the first rotational position, the second rotational direction being opposite to the first rotational direction.

10. The metering pump according to any one of claims 1 to 9, wherein: The predetermined torque value is 5 millinewtons meters to 15 millinewtons meters.

11. The metering pump according to any one of claims 1 to 9, wherein: The predetermined torque value is 5 millinewtons meters to 9 millinewtons meters.

12. The metering pump according to any one of claims 1 to 11, wherein: The interlock is configured to generate a maximum torque at least equal to a torque difference between a maximum operating pressure and a minimum operating pressure of the metering pump while maintaining fluid communication between the chamber and the outlet.

13. The metering pump according to any one of claims 1 to 12, wherein: The torque curve provided by the interlock is symmetrical as the sleeve moves between the first rotational position and the second rotational position.

14. The metering pump according to any one of claims 1 to 12, wherein: A maximum torque provided by the interlock when the sleeve moves from the first rotational position to the second rotational position is less than a maximum torque provided by the interlock when the sleeve moves from the second rotational position to the first rotational position.

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