For plunger rods and syringes that fail due to compression

Abstract

A plunger rod (104) for use in combination with a syringe barrel (102) is provided. The plunger rod (104) includes a distal plunger top (105) having a proximal bottom surface (113) and a proximal elongated shaft (106), the proximal elongated shaft (106) including a proximal end (107a) adapted to receive an applied force along an axis (1000) and a distal end plate (107b) adapted to transmit the applied force along the axis (1000). The plunger rod (104) is adapted to be inserted into the barrel (102) of a syringe (100) extending along the axis (1000). The distal plunger top (105) and the proximal elongated shaft (106) are connected to each other by a releasable connector (115). The releasable connector (115) comprises: a distal top breaking means (116) comprising at least one distal top rib (125a) eccentrically disposed with respect to an axis (1000) on a proximal bottom surface (113), and wherein a proximal shaft breaking means (117) comprises at least one proximal shaft rib (125b) eccentrically disposed with respect to an axis (1000) on a distal end plate (107b). Each of the at least one distal top rib (125a) is connected to a corresponding at least one proximal shaft rib (125b), the ribs (125a, 125b) being connected at a contact area (118), and wherein the distal top breaking means (116) is configured to separate from the proximal shaft breaking means (117) due to compression failure when the distal plunger top (105) is pushed into the distal end (110) in the barrel (102). A syringe is also provided.

Description

Technical Field

[0001] The invention relates to a plunger rod of a syringe, which is used to prevent the syringe from being reused, and the manufacturing cost thereof is similar to that of a traditional syringe. The invention also relates to a syringe comprising the plunger rod. Background Art

[0002] Injections are one of the most common healthcare procedures, with at least 16 billion injections performed worldwide each year. Multiple injections using the same syringe on multiple people can lead to the spread of multiple infectious diseases. It is estimated that more than 2 million patients and users are infected with serious blood-borne diseases such as HIV, hepatitis B and hepatitis C each year due to syringe misuse. Most of these injections are performed using conventional syringes or pre-filled conventional syringes available on the market.

[0003] In 2015, the World Health Organization (WHO) set a time limit of 2020 for all syringes worldwide to be replaced with so-called “smart syringes” such as auto-disabled (AD) syringes.

[0004] The auto-disabling syringes available on the market have several disadvantages. Most smart syringes are based on a locking mechanism between the plunger rod and the syringe barrel. When the plunger rod is inserted and reaches the front of the syringe barrel, the locking mechanism is activated. During an attempt to retract the plunger rod, a tensile failure occurs and the plunger rod breaks into two separate parts. Thus, the reuse of the syringe is prevented. Such an auto-disabling syringe is described, for example, in US 2013 / 0110044 A1.

[0005] However, these types of syringes have a complex design. For example, the inner wall of the barrel may include a flange and the piston rod is correspondingly designed to engage with the flange. This difficult design results in production costs that are substantially higher than the production costs of conventional syringes.

[0006] Another type of auto-disabling syringe is a syringe with a sharps protection feature (SIP) and a reuse prevention feature (RUP). SIP+RUP syringes are available in manual or automatic versions. In the manual version, the user manually activates the safety feature. Automatic retractable models are basically similar to the manual version, but they include a device, such as a spring, which automatically pulls the needle into the plunger once the plunger rod hits the bottom of the barrel. When pressure is applied to the plunger rod, the spring mechanism in the syringe is triggered, forcing the needle to retract into the syringe barrel. Therefore, after a single use, additional injections are impossible. This more or less eliminates the risk of injury due to contact with the needle during disposal. However, this design includes many different parts and multiple installation steps. This in turn results in very high production costs.

[0007] Therefore, there is a need for an auto-disabling syringe that addresses the disadvantages and shortcomings of the prior art and that can be manufactured in a cost-effective manner. Summary of the invention

[0008] Therefore, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-mentioned defects and disadvantages in the art, alone or in any combination, and to at least solve the above-mentioned problems by proposing solutions according to the attached independent claims. Advantageous embodiments are defined in the attached dependent claims.

[0009] In a first aspect, a plunger rod is provided for use in conjunction with a syringe. The plunger rod comprises a distal plunger top having a proximal bottom surface and a proximal elongated shaft, the proximal elongated shaft comprising a proximal end adapted to receive an applied force along an axis and a distal plate adapted to transmit the applied force along the axis. The plunger rod is adapted to be inserted into a syringe extending along the axis. The distal plunger top and the proximal elongated shaft are interconnected by a releasable connector, comprising a distal top breaking device having at least one distal top rib, the distal top rib being eccentrically disposed with respect to the axis on the proximal bottom surface, and the proximal shaft breaking device having at least one proximal shaft rib being eccentrically disposed with respect to the axis on the distal plate. Each at least one distal top rib is connected to a corresponding at least one proximal shaft rib, and the ribs are connected at a contact area. The distal top breaking device is configured to separate from the proximal shaft breaking device by compression failure when the distal plunger top is pushed into the distal end of the barrel.

[0010] In a second aspect, a syringe is provided, the syringe comprising a barrel having a syringe tip disposed at a distal end of the barrel. The barrel is adapted to contain a medicament and has a tubular wall extending from the distal end to the proximal end, the barrel extending along an axis. The barrel comprises an orifice disposed at a proximal end of the barrel and the syringe further comprises a plunger rod extending along the axis.

[0011] Further advantages will be apparent from the detailed description and the appended dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other aspects, features and advantages that can be achieved by the present invention will become apparent and elucidated from the following description of embodiments of the present invention, with reference to the accompanying drawings, in which

[0013] Figure 1A is a longitudinal view of a syringe and an isometric view of a plunger rod according to one example;

[0014] Figure 1B is based on Figure 1A A longitudinal view of a syringe and plunger rod of an example in FIG.

[0015] Figure 2 is a longitudinal view of a syringe and a plunger rod, and an isometric view of a plunger rod according to a second example;

[0016] Figure 3 is a longitudinal view of a syringe and a plunger rod, and an isometric view of a plunger rod according to a third example;

[0017] Figure 4 is a longitudinal view of a syringe and a plunger rod, and an isometric view of a plunger rod according to a fourth example;

[0018] Figure 5 shows a cross-sectional view of a syringe and plunger rod according to a fifth embodiment, and an isometric view of a plunger rod according to a fifth example;

[0019] Figure 6 According to the sixth example, Figure 4 Alternative examples of syringes and plunger rods shown;

[0020] Figure 7 According to the seventh example, Figure 4 Yet another alternative example of a syringe and plunger rod as shown in ; and

[0021] Figure 8 are longitudinal and isometric views of a prefilled syringe and plunger rod according to an eighth example. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to implement the present invention, embodiments of the present invention will be described in more detail below in conjunction with the accompanying drawings. However, the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. The embodiments do not limit the present invention, but the present invention is limited only by the attached patent claims. In addition, the terms used in the detailed description of the specific embodiments shown in the accompanying drawings are not intended to limit the present invention.

[0023] Referring to Fig. 1, an example of a syringe 100 and a plunger rod 104 according to the teachings herein is shown. The syringe 100 includes a barrel 102 having a distal end 110 and a proximal end 112. The distal end 110 includes a distal tip 111 to which a needle can be attached. The barrel 102 of the syringe 100 can be made of any material suitable for containing a drug, but is preferably made of plastic. The plastic is preferably transparent. The barrel 102 is configured to contain a drug. The drug can be in liquid form for injection into the body of a patient or user. In addition, the barrel 102 has a tubular wall 101.

[0024] The syringe 100 extends along an axis 1000 , which defines a direction in which the barrel 102 extends. For example, the barrel 102 extends along the axis 1000 .

[0025] The syringe 100 of FIG. 1 further includes a plunger rod 104 disposed within the barrel 102. The plunger rod 104 extends along the tubular wall 101 and the axis 1000. A washer 103 is disposed on a distal plunger top 105 of the plunger rod 104. The distal plunger top 105 includes a proximal bottom plate 113. The plunger rod 104 further includes an elongated proximal shaft 106 having a proximal end 107a and a distal end plate 107b.

[0026] The gasket 103 is adapted to be in fluid-tight engagement with the tubular wall 101 of the barrel 102. By being in fluid-tight engagement with the tubular wall 101 of the barrel 102, the drug or liquid contained in the barrel 102 is prevented from leaking out of the syringe 100 in any other direction except through the distal tip 111 on the distal end 110 of the barrel 102 (or a needle attached to the distal tip).

[0027] The distal plunger tip 105 and the elongated proximal shaft 106 are connected to each other via a releasable connection 115 . Figure 1A The releasable connector 115 includes a plurality of distal top breaking devices 116 and a plurality of proximal shaft breaking devices 117. The distal top breaking device 116 is arranged on the proximal bottom surface 113 of the distal plunger top 105. The proximal shaft breaking device 117 is arranged on the distal end plate 107 of the elongated proximal shaft 106. The distal top breaking device 116 on the proximal bottom surface 113 includes three distal top ribs 125a. The proximal shaft breaking device 117 on the distal end plate 107b includes three proximal shaft ribs 125b. The distal top rib 125a is arranged centrally relative to the proximal shaft rib 125b. Therefore, the proximal shaft rib 125b is arranged on the outside relative to the distal top rib 125a. Reference Figure 1B The connection between the distal top rib 125a and the proximal shaft rib 125b is further explained.

[0028] Figure 1A-8 Each of the examples shows a different non-limiting embodiment of a releasable connector 115 connecting the distal tip 105 to the proximal elongated shaft 106 of the plunger rod 104. In all embodiments, the axis 1000 defines a longitudinal direction of the syringe and the plunger rod, having a distal end and a proximal end. The axis 1000 extends along the center of the syringe. The perimeter of the plunger rod and the syringe barrel defines an outer perimeter.

[0029] The distal top rib 125a and the proximal shaft rib 125b of the releasable connector 115 disclosed herein are eccentrically arranged relative to each other and the axis 1000. When the plunger rod 104 receives a force applied along the axis 1000 so that the distal plunger top 105 is pushed into the distal end 110 of the barrel 102, the releasable connector 115 breaks. When the distal plunger top 105 reaches the distal end 110 and is further pressed toward the distal end 110, compression failure occurs between the distal top breaking device 116 and the proximal shaft breaking device 117, and they separate from each other. Therefore, when the user withdraws the plunger rod 104, the distal plunger top 105 will remain in the barrel 102, and only the elongated proximal shaft 106 is withdrawn from the barrel 102. Obviously, the syringe 100 cannot be reused.

[0030] Figure 1B Shows Figure 1A Cross-section of the plunger rod 104 in the use positions AE disclosed in FIG.

[0031] Position A (installed position): The plunger rod 104 is disposed within the barrel 102. The releasable connection 115 connects the distal plunger top 105 to the plunger rod 104.

[0032] In this embodiment, the releasable connector 115 is shown in an enlarged view of position A. The distal plate 107b and the proximal bottom surface 113 include three spaced apart proximal shaft ribs 125b and three spaced apart distal top ribs 125a, respectively. Figure 1B 114 is a longitudinal cross-sectional view, so only two distal top ribs 125a and two proximal shaft ribs 125b are visible. Each distal top rib 125a arranged on the proximal bottom surface 113 is paired and connected to the corresponding proximal shaft rib 125b arranged on the distal end plate 107b. The distal top rib 125a is connected to the proximal shaft rib 125b at a contact area 118. The longitudinal cross-sections of the distal top rib 125a and the proximal shaft rib 125b have a conical or pyramidal shape.

[0033] The distal top rib 125a of the distal top breaking device 116 and the proximal shaft rib 125b of the proximal shaft breaking device 117 are connected to each other along the extension of the axis 1000. Each distal top rib 125a is connected to a corresponding proximal shaft rib 125b. Two connected distal top ribs 125a and proximal shaft ribs 125b are arranged eccentrically relative to each other and the axis 1000. A center-facing surface (facing the axis 1000) of one proximal shaft rib 125b is connected to an outward-facing surface (away from the axis 1000) of the distal top rib 125a at the contact area 118. Therefore, the normal of the surface of the distal top rib 125a points laterally outward from the center. The normal of the surface of the proximal shaft rib 125b points toward the center towards the central axis 1000. This provides great stability in the lateral / center direction (perpendicular to the axis 1000). The distal top breaking device 116 is arranged centrally relative to the proximal shaft breaking device 117 , closer to the axis 1000 .

[0034] Position B (withdrawn position): The plunger rod 104 has been withdrawn, exposing a lumen 108 in the barrel 102. In the enlarged view of position B, the releasable connector 115 is intact and connects the distal plunger top 105 to the elongated shaft 106. In addition, the barrel 102 includes a flat angle 120 extending from the orifice 109 of the barrel 102 to a circumferential flange 119 formed on the inner wall of the barrel 102. This helps the gasket 103 contact the inner wall of the barrel 102 earlier during installation. In addition, this design prevents the accumulation of friction when the gasket 103 is to pass through the circumferential flange 119. In addition, the proximal bottom plate 113 has an inclined side edge 128, which also reduces friction when the proximal bottom plate 113 is to pass through the circumferential flange 119.

[0035] The diameter of the proximal base plate 113 is smaller than the diameter of the circumferential flange 119 to avoid contact between them, which may damage the releasable connector 115 during installation. The distal plate 107b ensures that after the drug is drawn into the lumen 108, the piston rod 104 cannot be withdrawn from the barrel 102.

[0036] Position C (Front Position - No Pressure Load): The plunger rod 104 has been pushed to the distal end 110 of the barrel 102. The pressure load that has been applied has been sufficient to expel the contents of the lumen 108 from the syringe 100, but has not applied sufficient force to cause compression failure of the releasable connector 115. The releasable connector 115 is therefore intact. A distal interface between the distal top rib 125a of the distal top break 116 and the proximal shaft rib 125b of the proximal shaft break 117 includes a weakening in the form of a sharp edge 122. A proximal interface between the distal top break 116 and the proximal shaft break 117 includes a reinforcement in the form of a bend 121. The sharp edge 122 acts as a weakening of the releasable connector 115, accelerating and promoting compression failure when the plunger rod 104 is pushed distally as further described with reference to position D. Conversely, the bend 121 prevents undesired tensile fracture from occurring during withdrawal of the plunger rod 104 as shown in position B.

[0037] Position D (Front Position - Compressive Load Applied): The plunger rod 104 has received further force along the axis 1000 and has therefore been pressed further toward and into the distal end 110 of the barrel 102. This results in the activation and rupture of the releasable connection 115. Compression failure occurs and the distal top rib 125a and the proximal shaft rib 125b are disconnected from each other. A cavity 114 allows the proximal shaft rib 125b to be pushed forward and compression failure occurs, even though the distal plunger top 105 has reached the distal end 110 and is in contact with the distal end 110. As shown in the enlarged portion of position D, there is no longer any direct contact between the distal top rib 125a and the proximal shaft rib 125b. When rupture occurs, the distal top rib 125a has a distal rib section 135 and the proximal shaft rib 125b has a proximal shaft rib section 136. The distal rib section 135 points toward the center. The proximal axial rib section 136 points outward.

[0038] Position E (distal plunger top detached): When the user withdraws the plunger rod 104 in the barrel 102, the distal plunger top 105 detaches from the plunger rod 104. Therefore, the syringe 100 cannot be reused. Each distal top rib 125a and proximal shaft rib 125b are inclined to each other (shown in the enlarged view of position A and position D). The angle between the center-facing surface of the rib 125b and the distal plate 107b is less than 90 degrees. The angle between the outward-facing surface of the rib 125a and the proximal bottom surface 113 is greater than 90 degrees. This reduces the risk of the distal top breaking device 116 and the proximal shaft breaking device 117 engaging each other when the distal plunger top 105 is to be disengaged from the plunger rod 104.

[0039] refer to Figure 2-8 , seven additional embodiments of plunger rods 204, 304, 404, 504, 604, 704, 804 will be described. Figure 2-7 The use of the plunger rod in the embodiments shown all includes positions AE. Figure 8 Position A is not included because Figure 8 The example in relates to a pre-filled auto-disabling syringe 800. Position A is the installed position. Position B is the withdrawal position, in which the lumen 108 of the barrel 102 is filled with a drug. Position C is the front position, in which the contents of the lumen 108 have been emptied, but no excessive force has been applied to the plunger rod 104. Therefore, the releasable connectors 115, 215, 315, 415, 515, 615, 715, 815 remain intact. Position D is the front position in which a pressure load has been applied and the releasable connector has undergone compression failure. In position E, which is the separation position, the distal plunger top 105 is detached from the plunger rod 104.

[0040] Figure 2 A plunger rod 204 according to a second embodiment is shown, comprising a releasable connection 215. The releasable connection 215 comprises a plurality of distal tip breaking means 216 disposed on a proximal bottom surface 213 of the distal tip 205. A plurality of shaft breaking means 217 are disposed on a distal end plate 207 of the elongated proximal shaft 206.

[0041] The distal top breaking device 216 and the proximal shaft breaking device 217 include two eccentrically disposed multiple distal top ribs 225a and multiple proximal shaft proximal shaft ribs 225b, respectively. The distal top breaking device 216 and the proximal shaft breaking device 217 may include more than two eccentrically disposed distal top ribs 225a and proximal shaft ribs 225b. The distal top ribs 225a and the proximal shaft proximal shaft ribs 225b are linearly disposed along a diameter of the bottom surface 213 and the distal end plate 207, respectively. The proximal shaft ribs 225b are disposed close to the center and closer to the axis 2000 relative to the distal top ribs 225a.

[0042] The distal top rib 225a includes two distal rib protrusions 223a, and the proximal shaft rib 225b includes two proximal rib protrusions 223b. The distal top rib 125a and the proximal shaft rib 125b are connected to each other by the distal rib protrusions 223a and the proximal shaft protrusions 223b. The protrusions are also referred to as fracture cones in this article. The distal rib protrusions 223a and the proximal shaft protrusions 223b extend radially from the distal top rib 225a and the proximal shaft rib 225b.

[0043] The distal rib projection 223a on the rib 225a points to the center. The proximal shaft projection 223b points to the outside along the same diameter of the linear arrangement of the distal top rib 225a and the proximal shaft rib 225b. Each distal rib projection 223a is connected to the corresponding proximal rib projection 223b. The corresponding distal rib projection 223a and proximal rib projection 223b are arranged to be longitudinally horizontal to each other so that they face each other. The distal rib projection 223a and proximal rib projection 223b connected form an hourglass shape connection between the distal top rib 225a and the proximal shaft rib 225b.

[0044] The hourglass-shaped connection formed by the distal rib protrusion 223a and the proximal rib protrusion 223b may include a weakened groove 224. Figure 2 In the embodiment, the grooves 224 are located at the nodes of the hourglass-shaped connection. The grooves 224 will accelerate the fracture during compression failure and enable sharp / obvious rupture.

[0045] The distal rib protrusions 223a and the proximal rib protrusions 223b may have different diameters and lengths. The smaller distance between the distal top rib 225a and the proximal shaft rib 225b prevents viscoelastic deformation and / or shearing of the distal rib protrusions 223a and the proximal rib protrusions 223b before compression failure occurs, thereby causing more effective / significant compression failure of the distal rib protrusions 223a and the proximal rib protrusions 223b. The distal rib protrusions 223a and the proximal rib protrusions 223b are linearly positioned on the distal top rib 225a and the proximal shaft rib 225b along the axis 2000 to use more than two distal rib protrusions 223a and proximal rib protrusions 223b.

[0046] When the fracture shown in position D occurs, the distal rib 225a has a distal rib section 235, and the proximal axial rib 225b has a proximal axial rib section 236. The distal rib section 235 points to the center, and the proximal axial rib section 236 points to the outside.

[0047] Figure 3 A plunger rod 304 according to a third embodiment is shown. The plunger rod 304 has a distal tip 305 and an elongated proximal shaft 306. The releasable connector 315 is similar to Figure 2The embodiment shown. The releasable connector 315 includes a plurality of distal top breaking means 316, which has two distal top ribs 325a eccentrically located on the proximal bottom plate 313. Two proximal shaft ribs 325b of the proximal shaft breaking means 317 are eccentrically arranged on the distal top 307b. The proximal shaft ribs 325b are arranged laterally relative to the distal top ribs 325a. The distal top ribs 325a and the proximal shaft ribs 325b extend along the axis 3000.

[0048] The distal top rib 325a and the proximal shaft rib 325b are linearly arranged along the bottom surface 313 and the central diameter of the distal end plate 307b, respectively. The proximal shaft rib 325b is arranged closer to the center than the distal top rib 325a and closer to the axis 3000.

[0049] The distal top ribs 325a each include a distal rib protrusion 323a, and the proximal shaft ribs 325b each include a proximal rib protrusion 323b. The distal top ribs 325a and the proximal shaft ribs 325b are connected to each other through the distal rib protrusions 323a and the proximal shaft protrusions 323b. The distal rib protrusions 323a and the proximal shaft protrusions 323b extend radially from the distal top ribs 325a and the proximal shaft ribs 325b.

[0050] The distal rib projection 323a on the rib 325a points to the center. The proximal shaft projection 323b points to the outside and along the same diameter of the linear arrangement with the distal top rib 325a and the proximal shaft rib 325b. Each distal rib projection 323a is connected to corresponding proximal rib projection 323b. Corresponding distal rib projection 323a and proximal rib projection 323b are arranged to be longitudinally horizontal to each other so that they face each other. The distal rib projection 323a and proximal rib projection 323b connected form an hourglass shape connection between distal top rib 325a and proximal shaft rib 325b.

[0051] The hourglass-shaped connection formed by the distal rib protrusion 323a and the proximal rib protrusion 323b may include a weakened groove 324 (at Figure 3 The position D in FIG. 2 is shown in an enlarged view. The groove 224 is located at the node of the hourglass-shaped connection. The groove 324 facilitates a sharp break between the cones 323.

[0052] The distal top rib 325a and the proximal shaft rib 325b are hexagonal and asymmetrical.An advantage of this embodiment is that the compression failure characteristics are easily optimized.

[0053] Use location AD such as Figure 3In position C, an enlarged view shows the third embodiment with and without the optional groove 324. In position D, the proximal shaft breaking device 317 has been disengaged from the distal top breaking device 316, and the proximal shaft rib 325b has been pushed into the cavity 314. Once compression failure is established (position D), the plunger rod 304 can be withdrawn from the barrel 302 (position E- Figure 3 When fracture occurs, the distal rib 325a has a distal rib section 335, and the proximal rib 325b has a proximal rib section 336. The distal rib section 335 points to the center, and the proximal rib section 336 points to the outside.

[0054] Figure 4 A fourth embodiment of a plunger rod 404 is shown. The plunger rod 404 has a distal plunger tip 405 and an elongated proximal shaft 406. The releasable connector 415 is similar to Figure 2 , and comprises a breaking device 416 having two distal top ribs 425a eccentrically located on the proximal bottom plate 413 of the distal top 405. Two proximal shaft ribs 425b of the proximal shaft breaking device 417 are eccentrically arranged on the distal top 407b.

[0055] The distal top rib 425a and the proximal shaft rib 425b extend along the axis 4000. Each distal top rib 425a includes two distal rib protrusions 423a. Each proximal shaft rib 425b includes two proximal rib protrusions 423b. The distal rib protrusions 423a and the proximal rib protrusions 423b extend substantially perpendicularly from the distal top rib 425a and the proximal shaft rib 425b and the axis 4000.

[0056] The distal top rib 425a and the proximal shaft rib 425b are connected to each other through the distal rib protrusion 423a and the proximal shaft protrusion 423b. The distal rib protrusion 423a and the proximal shaft protrusion 423b extend radially from the distal top rib 425a and the proximal shaft rib 425b.

[0057] The distal rib projection 423a on the rib 425a points to the center. The proximal shaft projection 423b points to the outside along the same diameter of the linear arrangement of the distal top rib 425a and the proximal shaft rib 425b. Each distal rib projection 423a is connected to the corresponding proximal rib projection 423b at a contact area 418. The corresponding distal rib projection 423a and the proximal rib projection 423b are arranged to be vertically horizontal to each other so that they face each other. The distal rib projection 423a and the proximal rib projection 423b connected form an hourglass shape connection between the distal top rib 425a and the proximal shaft rib 425b.

[0058] When broken, the distal rib 425a has a distal rib section 435 and the proximal rib 425b has a proximal rib section 436. The distal rib section 435 points to the center, and the proximal rib section 436 points to the outside.

[0059] The distal top rib 425a and the proximal shaft rib 425b are respectively provided linearly along the bottom surface 413 and the central diameter of the distal end plate 407. The proximal shaft rib 425b is located closer to the axis 4000 than the distal top rib 425a.

[0060] In this embodiment, the protrusion 423 is in the shape of a triangular prism. This results in the contact area 418 having a long width 426. Due to the elongated width 426, the embodiment of the releasable connector 415 has good stability. The contact area 418 may also include a reinforcement 427 facing the elongated shaft 406. The contact area 418 may also include a groove 424 facing the distal top 405.

[0061] Figure 5 A plunger rod 504 according to a fifth embodiment is shown. The distal end plate 507b and the proximal end bottom plate 513 each include two eccentrically disposed plurality of distal top ribs 525a and a plurality of proximal shaft ribs 525b.

[0062] Each distal top rib 525a includes a distal rib protrusion 523a. Each proximal shaft rib 525b includes a proximal side rib protrusion 523b. The distal top rib 525a and the proximal shaft rib 525b are connected to each other through the distal rib protrusion 523a and the proximal shaft protrusion 523b. The distal rib protrusion 523a and the proximal shaft protrusion 523b extend radially from the distal top rib 525a and the proximal shaft rib 525b.

[0063] The distal rib projection 523a on the rib 525a points to the center. The proximal shaft projection 523b points to the outside. Each distal rib projection 523a is connected to the corresponding proximal rib projection 523b at a contact area 518. The corresponding distal rib projection 523a and proximal rib projection 523b are arranged longitudinally horizontally to each other so that they face each other.

[0064] In contrast to the embodiment shown in FIGS. 1-4 , the distal rib projection 523a and the proximal shaft projection 523b in this embodiment are not linearly facing each other. Instead, the contact area 518 is formed by the overlap between the side edges of the distal rib projection 523a and the proximal shaft projection 523b. Each center-facing side edge of the distal rib projection 523a is connected to the center-facing side edge of the proximal rib projection 523b.

[0065] The two distal top ribs 525a are arranged eccentrically relative to the axis 5000 and relative to the proximal shaft ribs 525b. As shown in the enlarged view of position C, the distal top ribs 525a are arranged centrally relative to the proximal shaft ribs 525b. In addition, as can be seen in the enlarged view of the top view of the plunger rod 504, the distal top ribs 525a are also horizontally offset relative to the proximal shaft ribs 525b, and the horizontal direction is perpendicular to the longitudinal axis 5000. Therefore, the distal top ribs 525a and the proximal shaft ribs 525b are not arranged linearly along the diameter of the bottom surface 513 and the distal end plate 507b.

[0066] Preferably, the contact area 518 is relatively small, for example, 0.2 mm 2 The overlap in the contact area 518 provides stability during rotation of the plunger rod 504 within the barrel 502 .

[0067] When the plunger rod 504 is pushed to the front position and an excessive load is applied, the distal rib protrusion 523a and the proximal rib protrusion 523b are separated from each other, and the proximal shaft rib 525b is pushed into the cavity 514, as shown in FIG. Figure 5 Position D is shown in the enlarged figure.

[0068] When broken, the distal rib 525a has a distal rib section 535 and the proximal shaft rib 525b has a proximal shaft rib section 536. The distal rib section 535 and the proximal shaft rib section 536 face the central axis 5000.

[0069] Figure 6 The third embodiment ( Figure 3 ) of a plunger rod 604 with a releasable connection 615, wherein the gasket is an O-ring seal 603. Since the distal plunger top 605 is not covered by the gasket, such as Figure 3 As shown, in this embodiment, compression failure is performed when two solid and rigid polymers, such as polypropylene (PP), are in direct contact with each other. The distal end 610 of the barrel 602 is in direct contact with the top surface 629 of the distal plunger top 605 at positions C and D. This produces a sharper and more obvious rupture of the fracture cone 623. The O-ring seal 603 is made of an attenuating material, such as an elastomer, such as synthetic rubber or silicone. The O-ring seal 603 can be combined with any other embodiment disclosed herein.

[0070] Figure 7A plunger rod 704 according to a third embodiment is shown, wherein the syringe 700 further includes an additional locking mechanism 730. The plunger top 705 includes a terminal protrusion 731 extending from the top surface 729 through the gasket 703. The distal tip 711 of the syringe 700 includes an inner retaining wall 732 configured to engage a retaining portion 733 disposed on the terminal protrusion 731. The releasable connector 715 is connected to the Figure 3 and Figure 6 Same type as shown.

[0071] The addition of the locking mechanism 730 results in an automatically disabling syringe 700 that includes features that enable both compression failure and tension failure. Figure 7 733 is located near the distal end 710 of the barrel 702 and the distal tip 711 of the syringe 700. When the retaining portion 733 on the terminal protrusion 731 is pushed through the retaining wall 732, the locking mechanism is triggered. This is shown in the enlarged view of position C. In position D, the locking mechanism 730 has been engaged and the releasable connector 715 has been disengaged. In position E, the locking mechanism 730 is triggered, but the releasable connector 715 is still intact. As shown in the enlarged view of position F, if the releasable connector 715 fails to break during compression, the retaining portion 733 will engage in the retaining wall 732, and the plunger top 705 will be disengaged from the plunger rod 704 as shown in position G.

[0072] The additional locking mechanism 730 may be combined with any other releasable connector 115 , 215 , 315 , 415 , 515 , 615 , 815 of the embodiments disclosed herein.

[0073] exist Figure 7B In the Figure 7 Another embodiment of the syringe 700. The syringe 700' has a plunger rod 704' and Figure 7 The distal plunger top 705' includes a distal projection 731' extending from the top surface 729' through the gasket 703'. The distal tip 711' of the syringe 700' includes an inner retaining wall 732' configured to engage a retaining portion 733' disposed on the distal projection 731'. The releasable connector 715' is connected to the Figure 3 , 6 Same type as shown in 7.

[0074] In addition, the washer 703' has a central hole 737'. The distal plunger top 705' has a raised socket 738' extending through the central hole 737' of the washer 703'. The central hole 737' can be formed, for example, by injection molding or stamping. The diameter of the socket 738' is in the same range as the diameter of the central hole 737' or slightly wider. If the diameter of the socket 738' is greater than the width of the central hole 737', the socket 737' can be installed in the hole 738' by a press fit.

[0075] The distal end surface 739' of the socket 738' is located at the same longitudinal level as the washer 703', for example Figure 7B When the distal plunger top 705' reaches the distal end 710', the distal end surface 739' of the socket 738' and the distal end 710' of the barrel 702' are in direct contact with each other. Since the socket 738' and the distal end 710' preferably include two solid and rigid polymers, such as polypropylene (PP), the break between the plunger rod 704' and the distal plunger top 705' is sharper and more obvious, in the same manner as Figure 6 The embodiments shown are described identically.

[0076] Similar to Figure 3 In the embodiment shown, when Figure 6 , 7 When a break occurs between the distal plunger top 605, 705, 705' and the plunger rod 604, 704, 704' in 7B, the distal rib 625a, 725a, 725a' has a distal rib section 635, 735, 735' and the proximal shaft rib 625b, 725b, 725b' has a proximal shaft rib section 636, 736, 736'. The distal rib section 635, 735, 735' points to the center. The proximal shaft rib section 636, 736, 736' points to the outside.

[0077] refer to Figure 8 , shows a plunger rod 804 according to an eighth embodiment. The plunger rod 804 is designed to be disposed in a pre-filled syringe 800 and includes an elongated proximal shaft 806 and a distal top 805. The distal top 805 includes a proximal base plate 813 connected to a distal end plate 807 by a releasable connector 815, which is similar to Figure 5 The fifth embodiment of the present invention. The barrel 802 is preferably made of glass. In position A, the lumen 808 of the barrel 802 is filled with a liquid or a drug. The syringe 800 includes a needle 840 covered with a needle cover 841. The distal plunger top 805 includes a threaded protrusion 845 extending from the distal surface of the bottom plate 813.

[0078] When installing the pre-filled syringe 800, preferably, the washer 803 is first inserted into the hole 809 of the barrel 802. Subsequently, the plunger rod 804 is inserted into the hole 809 by screwing the threaded protrusion 845 into the washer 803. The releasable connector 815 in this embodiment is adapted to withstand such threads without being damaged during installation.

[0079] The releasable connector 815 includes a plurality of distal top ribs 825a and a plurality of proximal shaft ribs 825b eccentrically arranged on the bottom surface 813 and the distal plate 807, respectively. The bottom surface 813 and the distal plate 807 include two distal top ribs 825a and two proximal shaft ribs 825b, respectively. The proximal shaft ribs 825b are linearly arranged along the diameter of the distal plate 807b. The distal top ribs 825a are centrally arranged relative to the proximal shaft ribs 825b, closer to the axis 8000. The distal top ribs 825a each include a distal rib protrusion 823a. The proximal shaft ribs 825b each include a proximal rib protrusion 823b. The distal rib protrusion 823a and the proximal rib protrusion 823b are connected to each other at a contact area 818. The contact area 818 is located on a joint plane extending along the axis 8000 and passing through the axis 8000. The two distal top ribs 825a are arranged on opposite sides relative to the engagement plane. The two proximal shaft ribs 825b are arranged on opposite sides relative to the engagement plane. The two formed contact areas 818 are the central lateral overlap between the distal rib protrusions 823a and the proximal rib protrusions 823b.

[0080] therefore, Figure 8 The construction of the releasable connector 815 in is overlapping and cross-connected. The central lateral overlap of the contact area 818 enables the releasable connector 815 to withstand rotation, such as when assembling and installing a prefilled syringe. When the plunger rod 804 is rotated in one direction, the distal rib protrusion 823a will be pushed against the proximal rib protrusion 823b in the contact area 818. If the plunger rod 804 is rotated in the opposite direction, the proximal rib protrusion 823b will be pushed against the distal rib protrusion 823a in the contact area 818. Therefore, the construction of the releasable connector 815 is durable during both clockwise and counterclockwise rotation. Preferably, the contact area 818 is minimal, such as 0.2mm 2 .

[0081] The releasable connector 815' comprises an eccentrically arranged distal top rib 825a and a proximal shaft rib 825b. The distal top rib 825a is disposed on the bottom surface 813, and the proximal shaft rib 825b is disposed on the distal end plate 807b. In the same manner as described for the releasable connector 815, the distal top rib 825a and the proximal shaft rib 825b are connected to each other in an overlapping manner. The releasable connector 815' is, for example, suitable for a syringe having a small diameter barrel 802. In the same manner as described for the releasable connector 815, the overlap between the distal top rib 825a and the proximal shaft rib 825b enables the releasable connector 815' to withstand the rotation of the plunger rod 804.

[0082] when Figure 8 When a break occurs between the distal plunger top 805 and the plunger rod 804, the distal rib 825a has a distal rib section 835 and the proximal shaft rib 825b has a proximal shaft rib section 836.

[0083] The embodiment shown in Figures 1-8 minimizes the production cost of the automatic disabling syringe. Since the structure relies on the rupture caused by compression failure, rather than the interaction between the plunger rod and the syringe barrel, the plunger rod herein can be used with an existing syringe (Examples 1-6) or an existing pre-filled syringe (Example 8). The seventh embodiment requires the formation of an internal retaining groove 732. However, this feature is easy to manufacture during injection molding. The design disclosed herein is simpler than the features of existing syringes for tensile failure or spring loading. Therefore, the production cost can be reduced to the same or lower level as a conventional syringe or a conventional pre-filled syringe.

[0084] In addition, the new design provides good stability, which enables a high-speed installation process. In addition, the plunger rod disclosed herein can be made of different polymers suitable for medical devices, with changed material properties. The brittleness and impact strength of the polymer will affect the performance of the plunger rod. Therefore, the possibility of optimizing strength and compression failure during the process of extracting the plunger rod to fill the barrel with the drug is extensive.

[0085] All embodiments herein may include fewer or more ribs than the description of each example. In addition, each rib may include fewer or more protrusions extending from the rib. The ribs described as being closer to the axis may be arranged on the distal end plate of the proximal elongated shaft or on the proximal bottom surface of the distal plunger top. The ribs may have different sizes, i.e. different lengths and widths. The protrusions may have varying shapes and sizes.

[0086] Furthermore, the invention has mainly been described with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are possible within the scope of the invention, as defined by the appended claims.

[0087] In the claims, the term "comprises / comprising" does not exclude the presence of other elements or steps. Furthermore, although listed separately, multiple means, elements or method steps may be implemented by, for example, a single unit or processor. Furthermore, although individual features may be included in different claims, these features may be advantageously combined, and the inclusion in different claims does not mean that the combination of features is not feasible and / or advantageous. Furthermore, singular references do not exclude pluralities. The terms "a", "an", "first", "second", etc. do not exclude pluralities. Element numbers in the claims are provided merely as illustrative examples and should not be interpreted as limiting the scope of the claims in any way.

Claims

1. A plunger rod (104) for use in conjunction with a barrel (102) of a syringe (100), characterized in that: The plunger rod (104) includes a distal plunger top (105) having a proximal bottom surface (113), and a proximal elongated shaft (106) including a proximal end (107a) adapted to receive an applied force along an axis (1000) and a distal plate (107b) adapted to transmit the applied force along the axis (1000); wherein the plunger rod (104) is adapted to be inserted into the barrel (102) of the syringe (100) extending along the axis (1000); and The distal plunger top (105) and the proximal elongated shaft (106) are connected to each other via a releasable connection member (115), and the releasable connection member (115) comprises: a plurality of distal top breaking means (116), the distal top breaking means (116) comprising at least one distal top rib (125a) disposed eccentrically with respect to the axis (1000) of the proximal bottom surface (113); a plurality of proximal shaft breaking means (117), said proximal shaft breaking means (117) comprising at least one proximal shaft rib (125b) disposed eccentrically with respect to said axis (1000) of said distal plate (107b); Each of the at least one distal top rib (125a) is connected to a corresponding at least one proximal shaft rib (125b), the distal top rib (125a) and the proximal shaft rib (125b) are connected at a contact area (118), and the plurality of distal top breaking devices (116) are configured to separate from the plurality of proximal shaft breaking devices (117) due to compression failure when the distal plunger top (105) is pushed into a distal end (110) in the barrel (102); the diameter of the proximal bottom surface (113) is smaller than the diameter of the distal plate (107b).

2. The plunger rod according to claim 1, characterized in that: The distal top rib (125a) and the proximal shaft rib (125b) extend from the distal end plate (107b) and the proximal bottom surface (113) along the axis (1000), respectively.

3. The plunger rod according to claim 1, characterized in that: The plunger rod (104) further includes a cavity (114) formed between the proximal axial rib (125b) and the proximal bottom surface (113) of the distal end plate (107b), configured to receive the proximal axial rib (125b) when the applied force is transmitted along the axis (1000) to the distal plunger top (105) and causes the distal top rib (125a) and the proximal axial rib (125b) to release from each other.

4. The plunger rod according to claim 2, characterized in that: The distal top rib (125a) is radially offset relative to the proximal shaft rib (125b).

5. The plunger rod according to claim 1, characterized in that: When the distal top rib (125a) and the proximal shaft rib (125b) are disconnected from each other, the distal top rib (125a) has a distal rib section (135) and the proximal shaft rib (125b) has a proximal shaft rib section (136), which point to the center and the outside respectively relative to the axis (1000).

6. The plunger rod according to claim 2, characterized in that: The distal top rib (125a) and the proximal shaft rib (125b) are linearly aligned along the diameter of the proximal bottom surface (113) and the distal end plate (107b).

7. The plunger rod according to claim 1, characterized in that: The distal top ribs (125a) and the proximal shaft ribs (125b) extend along the axis (1000), and a centrally facing side of each distal top rib (125a) is connected to an outwardly facing side of a corresponding proximal shaft rib (125b), or vice versa.

8. The plunger rod according to claim 7, characterized in that: The distal top rib (125a) forms an angle with the axis (1000), and the proximal shaft rib (125b) is inclined toward the axis (1000), or vice versa.

9. The plunger rod according to claim 1, characterized in that: The distal top rib (125a) and the proximal axial rib (125b) are arranged as follows: one side edge of the distal top rib (125a), perpendicular to the side of the distal top rib (125a) away from the axis (1000), is connected to one side edge of the proximal axial rib (125b), perpendicular to the side of the proximal axial rib (125b) away from the axis (1000).

10. The plunger rod according to claim 1, characterized in that: The shapes of the distal top rib (125a) and the proximal shaft rib (125b) are substantially cones, cubes, cuboids, prisms, cones, tetrahedrons, cylinders or any other geometric three-dimensional shapes that enable connection between the distal top rib (125a) and the proximal shaft rib (125b).

11. The plunger rod according to claim 1, characterized in that: The distal top rib (125a) and the proximal shaft rib (125b) include at least one distal rib protrusion (123a) and a proximal rib protrusion (123b), respectively.

12. The plunger rod according to claim 11, characterized in that: Each distal rib protrusion (123a) faces the corresponding proximal rib protrusion (123b) and is arranged opposite to the corresponding proximal rib protrusion (123b), and wherein the distal rib protrusion (123a) and the proximal rib protrusion (123b) form a connection between the distal top rib (125a) and the proximal shaft rib (125b).

13. The plunger rod according to claim 12, characterized in that: The connection portion between each distal rib protrusion (123a) formed on the distal top rib (125a) and each corresponding proximal rib protrusion (123b) on the proximal shaft rib (125b) has a longitudinal cross-section along the axis (1000) having an hourglass-like shape.

14. The plunger rod according to claim 1, characterized in that: The distal plunger top (105) includes a gasket (103), wherein the gasket (103) is adapted to fluid-tightly engage with a tubular wall (101) of the barrel (102), and the gasket (103) can be displaced along the axis (1000) within the barrel (102).

15. The plunger rod according to claim 14, characterized in that The gasket (103) is an O-ring seal.

16. The plunger rod according to claim 1, characterized in that: The distal plunger top (105) also includes a terminal protrusion (731) arranged on the distal side of the distal plunger top (105), and the terminal protrusion (731) includes a retaining portion (733) configured to engage with an internal retaining groove (732) of the syringe tip (111) of the syringe (100).

17. The plunger rod according to claim 16, characterized in that: The distal plunger top (105) includes a raised socket (738') having a distal surface (739') arranged at a proximal end of the terminal protrusion (731) so that when the plunger top (105) is pushed into the distal end (110) of the barrel (102) of the syringe (100), the distal surface (739') is in direct contact with the distal end (110) of the barrel (102).

18. The plunger rod according to claim 11, characterized in that :The distal rib protrusion (123a) and the proximal rib protrusion (123b) are substantially cones, cubes, cuboids, prisms, cones, tetrahedrons, cylinders or any other geometric three-dimensional shapes that enable the distal rib protrusion (123a) and the proximal rib protrusion (123b) to be connected.

19. The plunger rod according to claim 1, characterized in that The contact area (118) includes a weakened portion arranged on a distal side of the contact area (118), wherein the weakened portion is a groove (124) or a sharp edge (122).

20. The plunger rod according to claim 1, characterized in that The contact area (118) includes a reinforcement member arranged on a proximal side of the contact area (118), and the reinforcement member is in the form of a bend (121) or an excess material (427).

21. The plunger rod according to claim 1, characterized in that The diameter of the proximal bottom surface (113) is smaller than the diameter of a circumferential flange (119) formed on an inner wall of the tube (102).

22. A syringe (100), characterized in that The syringe (100) comprises a barrel (102), wherein the barrel (102) has a syringe tip (111) arranged at a distal end (110) of the barrel (102), the barrel (102) is suitable for containing a drug, and the barrel (102) has a tubular wall (101) extending proximally from the distal end (110), so that the barrel (102) extends along an axis (1000), wherein the barrel (102) comprises an orifice (109) disposed at a proximal end of the barrel (102), and; Wherein, the syringe (100) further comprises a plunger rod (104) according to any one of claims 1 to 19, extending along the axis (1000).

23. The syringe (100) according to claim 22, characterized in that :The syringe (100) contains the medicine.

24. The syringe (100) according to claim 22 or 23, characterized in that :The cylinder (102) is made of plastic or glass.

25. The syringe (100) according to claim 22 or 23, characterized in that :The syringe tip (111) includes a needle (840).

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