Outer shell structure to assist in accurate syringe injections

Abstract

To provide an exostructure to assist in accurate syringe injection.SOLUTION: A syringe exostructure includes a main body which removably receives a syringe having a syringe barrel and a syringe plunger. A drive plunger is reciprocatably mounted on the main body, and a plunger bar is slidably received on the drive plunger. The plunger bar is configured to removably couple to the syringe plunger. A drive pawl is coupled to the drive plunger in order to transfer downward motion to the plunger bar as the drive plunger is advanced, and to disengage from the plunger bar as the drive plunger is retracted.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] This application claims the benefit of U.S. Patent Application No. 16 / 279,907 (Attorney Docket No. 54094 - 703.501), filed on February 19, 2019, the entire disclosure of which is incorporated herein by reference.

[0002] 1. Field of the Invention. The present invention generally relates to the field of medical devices and methods. More specifically, the invention described herein relates to devices and methods for delivering a dose of a drug from a syringe to a patient.

Background Art

[0003] Existing syringes utilize a plunger to push fluid out of a barrel through a needle into an injection site. In a typical clinical setting, the free hand of the operator uses the thumb to depress the plunger and the index and middle fingers placed on a flange to provide direction and stabilization to deploy the syringe. Using the standard free - hand injection method, existing disposable syringes function well when delivering the total volume of the barrel as a single measured dose. However, some clinical interventions (e.g., botulinum toxin, deoxycholic acid, and hyaluronic acid) require that the contents of the syringe be reproducibly dispensed in discrete units (i.e., doses) across multiple injection sites during the same procedure.

[0004] Free - hand injection is an inaccurate and imprecise technique for delivering discrete units to multiple sites during the same procedure with convenience. This practice subjects even skilled medical professionals to the risk of administering incorrect doses to injection sites. The risk of administering incorrect doses using the same syringe can result from several factors, including variations in the thumb force applied to the plunger required to reproducibly extrude the same volume of fluid from the syringe and measurement errors when attempting to visualize syringe markings at different angles.

[0005] Therefore, there is a need for devices and methods for administering precise volume units from syringes filled with sufficient drug volume for multiple dosages.

[0006] 2. Description of background technology. Background patents and publications include US2015025502, US4415101, US4022207, and US2491978. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2015-025502 [Patent Document 2] U.S. Patent No. 4415101 [Overview of the Initiative] [Means for solving the problem]

[0008] The present invention provides a syringe shell structure intended to receive a conventional syringe and needle assembly that is either pre-filled or adapted to be filled with a drug (but not limited to botulinum toxin, deoxycholic acid, and hyaluronic acid) to be delivered to a patient in multiple successive fractional amounts or doses having volumes typically in the range of 0.01 ml to 0.1 ml, and usually in the range of 0.025 ml to 0.05 ml. The total number of fractional amounts or doses may be in the range of 10 to 100, and typically in the range of 20 to 40, and the syringe may carry a total volume of drug in the range of 0.3 ml to 10.0 ml.

[0009] In a first aspect, the present invention provides a syringe shell structure comprising a main body, a drive plunger, a plunger bar, a drive claw, and a locking claw. The main body has an upper end and a lower end and is configured to removably receive a syringe having a syringe barrel and a syringe plunger. The syringe is typically pre-filled with a selected drug, and the drive plunger is mounted reciprocally on the main body. The plunger bar is slidably mounted relative to the drive plunger and has an upper end configured to removably engage with the syringe plunger when the syringe is received on the main body. The drive claw is located at the lower end of the drive plunger and is configured to engage with the plunger bar and transmit downward motion to the plunger bar when the drive plunger is advanced downward. The drive claw is further configured to disengage from the plunger bar when the drive plunger is retracted upward. This allows the drive plunger to progressively advance the plunger bar, as described in more detail below, thereby delivering a pre-selected dose of medication from the syringe. The locking claw is fixed to the main body and is configured to engage with the plunger bar to allow the plunger bar to advance downward when the drive plunger advances downward, but to prevent the plunger bar from being retracted upward when the drive plunger retracts upward.

[0010] In specific embodiments, the plunger bar has a toothed ratchet surface that engages with both a drive pawl and a locking pawl. In such cases, the locking pawl is preferably formed as an integrated hinge coupled to the main body and oriented toward the toothed ratchet surface, allowing downward movement of the plunger bar relative to the main body while preventing upward movement of the plunger bar relative to the main body. Similarly, the drive pawl may be formed as an integrated hinge at the lower end of the drive plunger and is typically oriented toward the toothed ratchet surface so as to cause downward movement of the plunger bar relative to the main body when the drive plunger is typically pressed down by the user's thumb. The drive pawl disengages from the toothed ratchet surface when the drive plunger is raised relative to the main body (typically by a return spring), while the plunger bar is held in place by the locking pawl.

[0011] In alternative embodiments, as further detailed below, the drive pawl comprises a pair of pawl assemblies, the pair of pawl assemblies forming a cam mechanism pivotably mounted on the drive plunger, and having tips configured to engage with opposing inner surfaces of a channel formed within the bottom of the plunger bar. Typically, the tip of each pawl in the drive pawl assembly comprises a toothed surface, the toothed surface configured to engage with a smooth, roughened, or toothed surface formed on the inner surface of the channel formed within the bottom of the plunger bar. The toothed surface on each pawl engages with the inner surface of the channel when the drive plunger is advanced and disengages from the inner surface of the channel when the drive plunger is retracted.

[0012] In a more specific example, the plunger bar may be slidably received within an axial channel formed on the drive plunger. The locking claw may extend through a slot, window, or other opening formed within the axial channel of the drive plunger, and the main body may comprise an upper shell having an upper surface with a syringe groove for removably receiving a syringe barrel, and a bottom shell having an upper surface for transporting the locking claw assembly. Furthermore, the main body may comprise a T-handle fixed to the main body having a slot or other receptacle for receiving a plunger button on the syringe.

[0013] In a further aspect of the present invention, a method for delivering multiple doses of a drug from a pre-filled syringe includes the steps of mounting the pre-filled syringe onto a syringe shell structure and coupling the plunger button of the pre-filled syringe to a plunger bar. The drive plunger is pushed downward, advancing the plunger bar downward by a predetermined distance, and consequently advancing the plunger button downward, thereby dispensing a predetermined dose of the drug from the syringe. After the dose is delivered, the drive plunger is retracted upward (typically by a return spring), while the plunger bar is immobilized relative to the syringe shell structure. Multiple sequential doses are delivered by repeating the second and third steps described above and delivering additional predetermined doses of the drug from the syringe.

[0014] In specific examples of these methods, the drive plunger may be coupled by a drive pawl to a toothed ratchet surface on the plunger bar. The plunger bar may further be immobilized by a locking pawl fixed to the syringe casing structure, which engages with the toothed ratchet surface on the plunger bar, allowing the plunger bar to advance downward relative to the syringe casing structure and preventing it from moving upward relative to the syringe casing structure.

[0015] In a further exemplary embodiment, the syringe shell structure comprises a main body configured to removably receive a syringe having a syringe barrel and a syringe plunger. A drive plunger is mounted reciprocally on the main body, and a plunger bar is slidably received in an axial channel on the drive plunger. The drive plunger is configured to removably couple with the syringe plunger when the syringe is introduced into the main body, and a drive pawl assembly is fixed to the upper surface of the drive plunger and configured to transmit the forward motion of the drive plunger to the plunger bar when the drive plunger is advanced, and further configured to disengage from the plunger bar when the drive plunger is retracted. A locking pawl assembly is fixed to the main body and extends through a slot, which is formed in the bottom of an axial channel in the drive plunger, and is configured to engage with the plunger bar, allowing the plunger bar to be advanced in one direction by the drive plunger when the drive plunger is advanced, but preventing the plunger bar from being retracted by the drive plunger when the drive plunger is retracted.

[0016] In an additional specific embodiment of the syringe shell structure of the present invention, the drive pawl assembly comprises a pair of pawls, the pair of pawls having tips configured to engage with opposing inner surfaces of a channel formed within the bottom of the plunger bar, forming a cam mechanism pivotably attached to the drive plunger. Typically, the tip of each pawl on the drive pawl assembly comprises teeth or other surfaces configured to engage with and drive the opposing inner surface of the channel formed within the bottom of the plunger bar, typically a smooth plastic surface. Typically, the engaging surface on each pawl engages with the meshing surface on the inner surface of the channel when the drive plunger is advanced and disengages from the surface on the inner surface of the channel when the drive plunger is retracted.

[0017] In a further specific embodiment of the syringe shell structure of the present invention, the main body comprises an upper shell having an upper surface with a syringe groove for removably receiving a syringe barrel, and a bottom shell having an upper surface for transporting a locking claw assembly. The main body may further comprise a hinged cover for enclosing the syringe barrel when placed in the syringe groove.

[0018] In other exemplary embodiments, a syringe shell structure constructed according to the principles of the present invention may comprise a main body front having a syringe groove, a flange slot, and a plunger shroud. A plunger bar comprises a plunger button mounting portion, a set of locking teeth, and a set of drive teeth. A plunger comprises a plunger head, a plunger spring, a set of drive pawls, a pawl spring, and a fastener. The main body rear comprises locking pawls and a spring mounting portion. The syringe groove may be enclosed by a hinged door attached to the main body front, and the plunger button mounting portion may be movably positioned between the flange slot and the plunger head. The plunger shroud may be positioned between the flange slot and the plunger head, and the set of drive teeth may be detachably coupled to the set of drive pawls using a pawl spring. The plunger spring may be elastically engaged with a spring mounting portion facing the plunger head, and the locking pawls may be detachably coupled to the set of locking teeth.

[0019] In further exemplary embodiments, the distance between the plunger head and the plunger shroud corresponds to the distance advanced by the locking claws between each tooth of the set of locking teeth, and the syringe shell structure may further feature being formed surrounding a flange slot.

[0020] In a further aspect of the present invention, the system may have any and / or all of the substitutions and combinations of features described previously. The present invention provides, for example, the following: (Item 1) Syringe shell structure, A main body having an upper end and a lower end, wherein the main body is configured to removably receive a syringe having a syringe barrel and a syringe plunger, the main body, A drive plunger mounted on the main body so as to be reciprocally movable, A plunger bar slidably disposed on the drive plunger, the plunger bar having an upper end, the upper end being configured to removably couple to the syringe plunger when the syringe is received on the main body, the plunger bar, A drive claw at the lower end of the drive plunger, the drive claw engaging the plunger bar and transmitting a downward movement to the plunger bar when the drive plunger is advanced downward, and disengaging from the plunger bar when the drive plunger is retracted upward, the drive claw, A locking claw fixed to the main body, the locking claw engaging the plunger bar and enabling the plunger bar to be advanced downward by the drive plunger when the drive plunger is advanced downward, but preventing the plunger bar from being retracted upward by the drive plunger when the drive plunger is retracted upward, the locking claw Comprising a syringe outer shell structure. (Item 2) The syringe outer shell structure according to item 1, wherein the plunger bar has a toothed ratchet surface engaged by both the drive claw and the locking claw. (Item 3) The locking claw is formed as an integral hinge coupled to the main body and is directed toward the toothed ratchet surface, the locking claw enabling downward movement of the plunger bar with respect to the main body and preventing upward movement of the plunger bar with respect to the main body, the syringe outer shell structure according to item 2. (Item 4) The drive claw is formed as an integral hinge at the lower end of the drive plunger, is directed toward the surface of the toothed ratchet, and causes a downward movement of the plunger bar relative to the main body when the drive plunger is advanced, and enables an upward movement of the drive plunger relative to the main body when the plunger bar is held in place by the locking claw. The syringe outer shell structure according to item 3. (Item 5) The drive claw comprises an assembly of a pair of claws, and the assembly of the pair of claws forms a cam mechanism pivotally attached to the drive plunger and has tips configured to engage with opposing inner surfaces of channels formed in the bottom of the plunger bar. The syringe outer shell structure according to item 1. (Item 6) The tip of each claw of the drive claw assembly comprises a toothed surface configured to engage with a surface formed on the inner surface of the channel formed in the bottom of the plunger bar. The toothed surfaces on each claw engage with the toothed surfaces on the inner surface of the channel when the drive plunger is advanced and disengage from the toothed surfaces on the inner surface of the channel when the drive plunger is retracted. The syringe outer shell structure according to item 5. (Item 7) The plunger bar is slidably received within an axial channel on the drive plunger. The syringe outer shell structure according to item 1. (Item 8) The locking claw extends through a slot formed in an axial channel of the drive plunger. The syringe outer shell structure according to item 7. (Item 9) The main body comprises an upper shell having an upper surface with a syringe barrel groove for removably receiving the syringe barrel, and a bottom shell having an upper surface for carrying the locking claw assembly. The syringe outer shell structure according to item 1. (Item 10) The syringe shell structure according to item 9, wherein the main body further comprises a T-handle fixed to the main body using a slot for receiving a plunger button on the syringe. (Item 11) A method for delivering multiple doses of a drug from a pre-filled syringe, (a) The steps of attaching the pre-filled syringe to the syringe shell structure and connecting the plunger button of the pre-filled syringe to the plunger bar of the syringe shell structure, (b) The steps of pressing the drive plunger on the syringe shell structure downward, advancing the plunger bar downward by a predetermined distance, advancing the plunger button downward, and dispensing a predetermined dose of the drug from the syringe, (c) The step of retracting the drive plunger upward while immobilizing the plunger bar relative to the syringe shell structure, (d) Repeat steps (b) and (c), and deliver an additional predetermined dose of the drug from the syringe. Methods that include... (Item 12) The method according to item 11, wherein the drive plunger is coupled to the toothed ratchet surface on the plunger bar by a drive pawl coupled to the drive plunger. (Item 13) The method according to item 12, wherein the plunger bar is immobilized by a locking claw fixed to the syringe shell structure, the locking claw engaging with the toothed ratchet surface on the plunger bar, allowing the plunger bar to advance downward relative to the syringe shell structure and preventing the plunger bar from moving upward relative to the syringe shell structure. [Brief explanation of the drawing]

[0021] To facilitate the identification of any particular element or action in discussion, the most significant digit or number of digits in the reference number refer to the figure number in which that element is first introduced.

[0022] [Figure 1] Figure 1 illustrates a first embodiment of a syringe shell structure constructed according to the principles of the present invention, as shown in the exploded view.

[0023] [Figure 2] Figure 2 shows a top view of the syringe shell structure shown in Figure 1.

[0024] [Figure 3] Figure 3 shows a side view of the syringe shell structure shown in Figure 1.

[0025] [Figure 4] Figure 4 shows the proximal end or "plunger" end of the syringe shell structure shown in Figure 1.

[0026] [Figure 5] Figure 5 is a perspective view of a second exemplary embodiment of a syringe shell structure constructed according to the principles of the present invention.

[0027] [Figure 6] Figure 6 illustrates an exemplary plunger bar incorporated into the embodiment shown in Figure 5.

[0028] [Figure 7] Figure 7 illustrates an exemplary drive plunger incorporated into the embodiment shown in Figure 5.

[0029] [Figure 8] Figure 8 illustrates an exemplary T-handle incorporated into the embodiment shown in Figure 5.

[0030] [Figure 9] Figure 9 illustrates an exemplary locking claw assembly incorporated into the embodiment shown in Figure 5.

[0031] [Figure 10] Figure 10 illustrates an exemplary lower cap or bracket incorporated into the embodiment shown in Figure 5.

[0032] [Figure 11] Figure 11 is a side cross-sectional view of the syringe shell structure embodiment shown in Figure 5.

[0033] [Figure 12] Figure 12 is a detailed exploded view showing the details of the drive claw and locking claw when they engage with the plunger bar in the embodiment of Figure 5.

[0034] [Figure 13] Figure 13 is a detailed view of the upper part of the syringe casing structure shown in Figure 5, illustrating the engagement of the syringe plunger button by the drive plunger.

[0035] [Figure 14A] Figures 14A-14C illustrate step by step how the drive claw and locking claw advance the drive plunger according to the method of the present invention. [Figure 14B] Figures 14A-14C illustrate step by step how the drive claw and locking claw advance the drive plunger according to the method of the present invention. [Figure 14C] Figures 14A-14C illustrate step by step how the drive claw and locking claw advance the drive plunger according to the method of the present invention. [Modes for carrying out the invention]

[0036] Syringe shell structures assist in the precise delivery of individual units from standard single-use, disposable syringes filled with multiple doses. Syringe shell structures are single-use and disposable and can be configured to accommodate different syringe sizes and dosing requirements. Syringe shell structures include formed features that ergonomically replicate the feel of a standard syringe. The syringe shell structure holds the syringe in place while a cam mechanism advances the syringe plunger a set distance within the syringe barrel, discharging a volume measured by the compression of each exoskeleton plunger. Tactile and / or audible feedback(single or multiple) is provided when the plunger is compressed. The filled syringe is held within the main body of the syringe shell structure and secured in place by the formed features and a hinged door that permanently closes and prevents tampering.

[0037] The plunger button of the syringe engages with a plunger bar that advances a set distance toward the flange and syringe barrel when the plunger is compressed. The advance of the plunger bar is driven by a set of drive pawls connected to the plunger, which disengages to advance the plunger bar forward, then returns to its starting position with the plunger, and reengages with the plunger bar closer to the plunger button. The distance advanced by the plunger head relative to the plunger shroud corresponds to the distance advanced by the locking pawls between each tooth of the set of locking teeth. During each advance of the plunger bar, the locking pawls disengage the plunger bar and reengage when the plunger returns to its starting position, preventing the plunger bar from reversing direction. Once the contents of the syringe have been discharged, the entire outer shell structure is discarded and cannot be reused, provided the syringe remains undamaged.

[0038] On one side, the syringe shell structure includes a main body front having a syringe barrel groove, a flange slot, and a plunger shroud; a plunger bar having a plunger button mounting section; a set of locking teeth; and a set of drive teeth. The plunger used in conjunction with the syringe shell structure includes a plunger head; a plunger spring; a set of drive pawls; a pawl spring; and a fastener connecting the pawl spring and the set of drive pawls to the plunger. The main body rear portion of the shell structure includes locking pawls and a spring mounting section.

[0039] The syringe groove is positioned to be sealed into a hinged door mounted on the front of the main body, and the plunger button is movably positioned between the flange slot and the plunger head. The plunger shroud is positioned between the flange slot and the plunger head. The set of drive teeth is detachably coupled to the set of drive pawls using a pawl spring, which elastically engages with a spring mount facing the plunger head. The locking pawl is detachably coupled to the set of locking teeth.

[0040] Referring to Figure 1, the syringe casing structure 100 includes a door 102, a hinge pin 106, a main body front 108, a plunger bar 110, a fastener 112, a first drive claw 114, a claw spring 116, and a second drive claw 118. The plunger 120 includes a plunger head 134, and the main body rear 122 includes a locking claw 126 and a spring mounting section 144. The plunger bar 110 includes a plunger button mounting section 136. The main body front 108 includes a syringe barrel groove 142, a flange slot 138, and a plunger shroud 140.

[0041] The syringe shell structure 100 engages with a standard disposable syringe 104, which includes a syringe barrel 128, a flange 130, and a plunger button 132. The syringe shell structure 100 delivers a highly controlled volume of fluid from the syringe 104 in response to the compression of the plunger 120. The main body front 108 includes a formed cavity for receiving the syringe 104. The formed cavity includes structures for retaining the flange 130 and syringe barrel 128 of the syringe 104. The flange slot 138 is surrounded by a protruding structure similar to an enlarged version of the flange 130. The main body front 108 includes a hinge for mounting a door 102 adjacent to the syringe barrel of the syringe 104. The hinge of the door 102 and the main body front 108 are secured through a hinge pin 106. While fixed using the hinge pin 106, the door 102 swings and surrounds the syringe 128 of the syringe 104 in the cavity formed in the main body front 108.

[0042] The plunger bar 110 engages with the plunger button 132 of the syringe 104. The plunger bar 110, the plunger 120, and the main body back surface 122 are aligned to match the length of the syringe 104. The plunger bar 110 is operably coupled to the plunger 120 through a first drive pawl 114 and a second drive pawl 118, and to the main body back surface 122 through a locking pawl 126. The first drive pawl 114 and the second drive pawl 118 are mounted on the plunger 120 through fasteners 112. The first drive pawl 114 and the second drive pawl 118 elastically engage with the plunger bar 110 using a pawl spring 116. The plunger head 134 of the plunger 120 protrudes from the main body back surface 122. The plunger 120 is elastically coupled to the main body back surface 122 through the plunger spring 124. The locking claw 126 on the back of the main body 122 passes through the bottom of the plunger 120 across the slotted opening and engages with the plunger bar 110 on the opposite side of the syringe 104.

[0043] During the operation of the syringe casing structure 100, the plunger head 134 is pushed toward the main body rear surface 122 until the plunger head 134 aligns with the main body rear surface 122. The movement of the plunger head 134 toward the main body rear surface 122 pushes the fluid out of the syringe barrel 128 of the syringe 104. This push occurs when the first drive pawl 114 and the second drive pawl 118 move the plunger bar 110, driving the plunger button mounting portion 136 toward the flange 130 and pushing the plunger button 132 into the syringe barrel 128. The first drive pawl 114 and the second drive pawl 118 drive the movement of the plunger bar 110 toward the flange 130 while the plunger spring 124 is compressed, repositioning the locking pawl 126 closer to the plunger button 132.

[0044] When the plunger head 134 is released, the pawl spring 116 compresses, allowing the first drive pawl 114 and the second drive pawl 118 to move toward the plunger button 132 to the length of the plunger bar 110 as the plunger 120 returns to its starting position. The plunger bar 110 is held in place relative to the movement of the plunger 120 through the engagement of the locking pawl 126. The distance the plunger head 134 travels toward the rear of the main body 122 is a set distance that matches the distance the locking pawl 126 travels toward the plunger bar 110, resulting in a matched volume being pushed out with each compression of the plunger head 134. The locking pawl 126 typically engages with a toothed or "ratcheted" surface formed on the bottom of the plunger bar 110, allowing the plunger bar to move forward when the plunger 120 is pressed and preventing the plunger bar from moving backward when the plunger returns to its initial position. Typically, the locking claw 126 also provides audible and / or tactile feedback when the toothed or ratcheted bottom of the plunger bar 120 is advanced by the plunger 110 on the locking claw.

[0045] Figure 2 shows a front view of one embodiment of the syringe shell structure 100, and shows the door 102, the main body front 108, the flange 130, the plunger button 132, the plunger head 134, the plunger button mounting section 136, the flange slot 138, and the plunger shroud 140.

[0046] Figure 3 shows a side view of the syringe shell structure 100, showing the door 102, the main body front 108, the main body rear 122, the plunger head 134, and the flange slot 138.

[0047] Figure 4 shows a top elevation view of one embodiment of the syringe shell structure 100, showing the main body front 108, the main body rear 122, and the plunger head 134.

[0048] A second embodiment of the syringe shell structure of the present invention is illustrated in Figures 5 to 14A-14C. Referring particularly to Figures 5-11, the syringe shell structure 200 comprises a main body having a lower portion 201a and an upper portion 202b. A T-handle 204 is fixed to the main body between the upper and lower portions. The drive plunger 206 and plunger bar 208 are mounted within the upper portion of the main body 202b, typically within a channel 203, as best seen in Figure 5.

[0049] The plunger bar 208 will typically have a plurality of ratchet teeth 210 formed on its front surface. The ratchet teeth 210 allow the reciprocating movement of the drive plunger 206 to advance the plunger bar 208 progressively, as will be described in more detail below.

[0050] A conventional syringe S comprises a syringe barrel BR having a syringe plunger SP and a plunger button SB. The lower end of the syringe S above the needle N is held in place by the lower cap or bracket 212 of the exoskeleton, while the flange F on the central portion of the syringe is held in a slot 236 in the T-handle 204, and the upper end of the syringe is held by being attached to the plunger button SB in a slot 246 in the button mounting portion 244 of the plunger bar 208, as seen in Figure 13. The syringe plunger SP passes downward through a cutout 248 in the button mounting portion 244.

[0051] Referring here to Figure 7, the drive plunger 206 has a head 224 that is typically manually pressed by the user using their thumb, and a channel 226 is formed within the front surface of the head for receiving the plunger bar 208, as is best observed in Figures 12 and 13. A window 228 is formed within the lower end of the drive plunger 206 above the drive claw 230, and the window and drive claw structures together form a single hinge 231, as is also seen in Figure 12.

[0052] Details of the T-handle 204 can be seen in Figure 8. The T-handle includes a base 234 having a pair of lateral phalanx receiving portions 235 at its upper end. The base 234 has a passage 240 for receiving the main body of the syringe, as is best seen in Figure 5. A slot 236 formed in the plane of the surface of the T-handle 204 removably receives the phalanx on the syringe, and the syringe plunger SP passes upward through a groove 238.

[0053] A locking pawl assembly 216 is shown in Figure 9. The assembly includes a locking pawl 218 formed at its lower end and a yoke 220 formed at its upper end. The locking pawl 218 is attached to the yoke by an integrated hinge 219, which allows the pawl to pivot or flex when force is applied to the locking pawl by ratchet teeth 210 on a plunger bar 208, as will be described in more detail below herein.

[0054] Referring here to Figure 10, the lower cap or bracket 212 includes a ring 213 that is received around the lower end of the lower portion 202a of the main body. A clasp or bracket 214 is formed on its front surface, as is best seen in Figure 5, and removably receives the lower end of the syringe.

[0055] Referring now to Figure 11, the assembly of the syringe S within the syringe shell structure 200 is shown in a partial cross-section. In particular, it can be seen that the syringe button SB is received in the button mounting portion 244 of the plunger bar 208, and the lower end of the toothed ratchet surface 210 of the plunger bar is engaged by the locking pawl 218 and the drive pawl 230.

[0056] Referring here to Figures 11 and 12, when the syringe is unused and the syringe plunger is not pressed, the drive pawl 230 first engages with the lower teeth of the toothed ratchet surface 210. The locking pawl 218 also engages with the toothed ratchet surface 210 through a window 228 formed in the drive plunger 206, as shown in Figure 13, and is coupled to the lower end of the drive plunger 206 by an integrated hinge 231. The channel 203 of the upper portion 202a of the main body receives the drive plunger 206, and consequently, the channel 226 and the drive plunger slidably receive the plunger bar 208. The syringe plunger SP is mounted such that the plunger button SB is in the slot 244.

[0057] Referring here to Figures 14A-14C, the forward movement of the syringe plunger SP by continuously pressing the drive plunger head 224 is described. The drive plunger 206 and plunger bar 208 are shown in their initial configuration in Figure 14A, with the plunger bar extending completely vertically as shown in Figures 5 and 11. By pressing the drive plunger head 224, the drive pawl 230 on the drive plunger 206 is driven downward, engaging with the lower teeth on the toothed ratchet surface 210 of the plunger bar 208. As the plunger bar 208 moves downward, the locking pawl 218 is displaced to the right (relative to the image in Figures 14A-14C), allowing the adjacent teeth to pass the locking pawl downward. After the drive plunger 206 is fully depressed, the plunger bar 208 is in the configuration shown in Figure 14, and the syringe plunger is correspondingly depressed to dispense a certain dose of medication. After the driver plunger 206 is fully depressed, the spring 252 moves the drive plunger back upward, as shown in Figure 14C. The engagement of the locking pawl 218 with adjacent teeth on the ratchet tooth surface 210 will immobilize the plunger bar 208 so that the plunger bar remains in place as the drive plunger moves upward to return to its initial position. The drive pawl 230 is displaced to the right as the adjacent teeth move upward in a conventional ratchet motion. As shown in Figure 14C, the plunger bar 208 is now displaced downward relative to its initial position by the notch, as shown in Figure 14A. Pressing the drive plunger 206 can be repeated to continuously press the plunger bar 208 until the plunger bar 208 is fully extended and the drug is fully delivered from the syringe, in order to deliver multiple doses of the drug.

[0058] The examples described above are not intended to limit the scope of the invention. Any modifications, equivalents, and substitutions are within the scope of the invention.

Claims

1. A device for delivering one or more individual units of a drug, wherein the device is a) An outer shell structure configured to be attached to a syringe comprising a plunger and a syringe barrel, b) A locking claw assembly comprising a locking claw and a yoke integrally connected to the locking claw, wherein the yoke is configured to at least partially surround the plunger, and the locking claw of the locking claw assembly is operably coupled to the outer shell structure, and Equipped with, The outer shell structure comprises a main body for holding the syringe, The yoke of the locking claw assembly is fixed to the main body, The locking claw assembly is configured to deliver a single individual unit of the drug from among the one or more individual units for each of the multiple set distances, by allowing the plunger to be advanced in a first direction by a plurality of set distances. The locking claw assembly is further configured to prevent the plunger from being retracted in a second direction opposite to the first direction, The locking claw assembly, when displaced, causes the plunger to advance by a set distance out of a plurality of set distances, by generating tactile feedback or audible feedback or both when the plunger is pressed.

2. The device according to claim 1, wherein the outer shell structure is permanently attached to the syringe.

3. The device according to claim 1, wherein the syringe is disposable.

4. The device according to claim 1, wherein the outer shell structure further comprises a plunger bar movable relative to the main body, and the plunger bar further comprises one or more ratchet surfaces.

5. The device according to claim 4, wherein the locking claw engages with one or more ratchet surfaces of the plunger bar, thereby preventing the plunger from being retracted in the second direction and enabling the plunger to be pushed in the first direction.

6. The device according to claim 5, wherein engaging the locking claw with one or more ratchet surfaces of the plunger bar generates tactile feedback or audible feedback or both when the plunger is pressed.

7. The device according to claim 1, wherein each of the one or more individual units of a drug comprises a measured volume of the drug, and the drug is contained within the syringe of the syringe.

8. The device according to claim 7, wherein pushing the plunger in the first direction delivers the chemical, the chemical comprising a liquid.

9. The device according to claim 8, wherein pushing the plunger in the first direction delivers the measured volume of the liquid, which contains a volume of 0.01 mL to 0.1 mL.

10. The device according to claim 9, wherein pushing the plunger in the first direction delivers the measured volume of the liquid, which contains a volume of 0.025 mL to 0.05 mL.

11. The device according to claim 1, wherein the plunger is repeatedly pressed in the first direction and repeatedly engages with the locking claw to deliver a repeatedly measured volume of the drug.

12. The device according to claim 1, wherein the plunger delivers 10 to 100 individual units of the drug by being repeatedly pressed.

13. The device according to claim 12, wherein the plunger delivers 20 to 60 individual units of the drug by being repeatedly pressed.

14. The device according to claim 1, wherein the outer shell structure houses the locking claw assembly.

15. The device according to claim 14, wherein the outer shell structure houses the locking claw assembly so that the outer shell structure prevents external access to the locking claw assembly.

16. The device according to claim 1, wherein the locking claw assembly is pivotably actuated.

17. The device according to claim 1, wherein the syringe is attached to the outer shell structure and is disposable.

18. The device according to claim 1, wherein at least a portion of the locking claw is flexible.

19. The device according to claim 1, wherein the locking claw is integrally connected to the yoke by an integrated hinge.

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