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EP-4267218-B1 - SIMPLE MEDICAMENT DELIVERY DEVICE

EP4267218B1EP 4267218 B1EP4267218 B1EP 4267218B1EP-4267218-B1

Inventors

  • BOSTRÖM, Anders

Dates

Publication Date
20260506
Application Date
20211209

Claims (12)

  1. A medicament delivery device (1; 1') comprising: a front assembly (3), and a rear assembly (5) configured to be attached to the front assembly (3), wherein the front assembly (3) has a front body (11; 11') and a syringe holder (13; 13') arranged in the front body (11; 11'), wherein the rear assembly (5) has a rear body (19) provided with a plunger rod (19e), wherein the front body (11; 11') is configured to move axially relative to the rear body (19) to enable the plunger rod (19e) to move forward inside the syringe holder (13; 13'), wherein the front assembly (3) and the rear assembly (5) are configured to be attached by means of a bayonet connection, wherein the front body (11; 11') has a radial pin (11d) forming one part of the bayonet connection and the rear body (19) has a bayonet slot (19b) forming another part of the bayonet connection, and wherein the pin (11d) is configured to run in the bayonet slot (19b), wherein the bayonet slot (19b) transitions into an axial slot (19c) extending rearwards along the rear body (19), wherein the pin (11d) is configured to run in the axial slot (19c) to enable axial movement of the front body (11; 11') relative to the rear body (19) when the front body (11) and the rear body (19) are locked by the bayonet connection, and wherein the rear body (19) has an outer shell (19d), and the plunger rod (19e) is arranged immovable relative to the outer shell (19d), wherein the plunger rod (19e) extends in the forward direction inside the outer shell (19d).
  2. The medicament delivery device (1; 1') as claimed in claim 1, wherein the axial length of the axial slot (19c) defines a stroke length of the front body (11; 11').
  3. The medicament delivery device (1; 1') as claimed in any of claims 1-2, wherein the pin (11d) is provided on an outer surface of the front body (11; 11') and the bayonet slot (19b) extends radially through the rear body (19).
  4. The medicament delivery device (1; 1') as claimed in claim 3, comprising an outer rear body (7) configured to receive the rear body (19) and a rear part of the front body (11; 11'), wherein the outer rear body (7) has an axial rib (7c) provided on its inner surface, the axial rib (7c) being configured to restrict movement of the pin (11d) in the bayonet slot (19b) to maintain the front body (11; 11') and the rear body (19) in a locked state.
  5. The medicament delivery device (1; 1') as claimed in claim 4, wherein the outer rear body (7) has a front flange (7a) provided with a radial opening (7b) aligned with the mouth (20) of the bayonet slot (19b), the radial opening (7b) being configured to receive the pin (11d) when the front assembly (3) and rear assembly (5) are assembled or disassembled with each other.
  6. The medicament delivery device (1; 1') as claimed in claim 4 or 5 dependent on claim 3, wherein the outer rear body (7) has a release button (9) which in a default position has a radially inwards extending structure (9a) configured to prevent axial movement of the pin (11d) rearwards in the axial slot (19c), to thereby prevent the front body (11; 11') to move axially rearwards relative to the rear body (19), wherein the release button (9) is configured move the radial structure radially outwards (9a) when the release button (9) is depressed to enable the pin (11d) to run rearwards in the axial slot (19c).
  7. The medicament delivery device (1; 1') as claimed in claim 6, wherein the release button (9) has a seesaw-structure with one end being provided with the radially inwards extending structure (9a).
  8. The medicament delivery device (1; 1') as claimed in any of the preceding claims, comprising a front resilient member (13a) arranged in the front body (11) and configured to bias the syringe holder (13; 13') towards a rear end of the front body (11; 11').
  9. The medicament delivery member (1; 1') as claimed in any of the preceding claims, comprising an axially movable syringe stop (17) arranged in the rear body (19) concentrically with the plunger rod (19e), wherein the syringe stop (17) has radial protrusions (17b) and the rear body (19) comprises axial slots (19a) in which the radial protrusions (17b) are configured to run to guide axial movement of the syringe stop (17), and a rear resilient member (21) configured to bias the syringe stop (17) towards a front end of the rear body (19).
  10. The medicament delivery device (1; 1') as claimed in claim 9, wherein the syringe stop (17) is configured to bear against a rear end of the syringe holder (13).
  11. The medicament delivery device (1; 1') as claimed in claim 9 or 10, wherein the rear resilient member (21) has a higher stiffness than the front resilient member (13a).
  12. The medicament delivery device (1; 1') as claimed in any of the preceding claims, wherein the front body (11) is a needle cover.

Description

TECHNICAL FIELD The present disclosure generally relates to medicament delivery devices. BACKGROUND Medicament delivery devices such as injectors are nowadays often handled by the end user during medicament delivery. Some medicament delivery devices contain a syringe. Syringes are used for a single medicament delivery operation. In some cases, the entire medicament delivery device may be disposable so that a user only has to be concerned about the medicament delivery operation and the disposal of the medicament delivery device. In other cases, the medicament delivery device may be configured to be used multiple times. This requires changing of the syringe. Such an operation may be relatively complex, especially if the user has a functional impairment. US2013/0267897A1 describes a back-end device of an autoinjector adapted to be attached to a packaged syringe. JP2014/079375A describes a liquid administration device which makes it possible for a user having difficulties in pressing and operating an operating member, to administer liquid easily and reliably. US3605744A1 describes an injection apparatus usable for both pre-injection and completing the injection of an anesthetic. US2016/0175528A1 describes a substance delivery device for use with a container containing the substance. US2020/0054838A1 describes a device for the parenteral delivery of a medication, such as a drug. US2011/0306936A1 describes a medicament delivery device comprising a front housing and a rear housing connected to each other. SUMMARY It would be desirable to provide a multi-use medicament delivery device for syringes, which is simple to handle for the user. The invention is defined by the appended claims. An object of the present disclosure is to provide a medicament delivery device which solves, or at least mitigates problems of the prior art. There is hence provided a medicament delivery device comprising: a front assembly, and a rear assembly configured to be attached to the front assembly, wherein the front assembly has a front body and a syringe holder arranged in the front body, wherein the rear assembly has a rear body provided with a plunger rod, wherein the front body is configured to move axially relative to the rear body to enable the plunger rod to move forward inside the syringe holder, wherein the front assembly and the rear assembly are configured to be attached by means of a bayonet connection. A medicament delivery device which is simple to assembly when loading with a syringe and to disassemble when removing a used syringe can thereby be provided. The bayonet connection ensures simple handling for connecting and disconnecting the front assembly and the rear assembly before and after use of the medicament delivery device. With "rearwards" and "rearward direction" as used herein is meant an axial direction from the front body towards the rear body. With "forward" and "forward direction" is meant an axial direction from the rear body towards the front body. According to the invention the front body has a radial pin forming one part of the bayonet connection and the rear body has a bayonet slot forming another part of the bayonet connection, and wherein the pin is configured to run in the bayonet slot. According to the invention the bayonet slot transitions into an axial slot extending rearwards along the rear body, wherein the pin is configured to run in the axial slot to enable axial movement of the front body relative to the rear body when the front body and the rear body are locked by the bayonet connection. According to one embodiment the axial length of the axial slot defines a stroke length of the front body. The stroke length is the amount that the front body is configured to be moved axially relative to the rear body to perform medicament delivery. According to one embodiment the pin is provided on an outer surface of the front body and the bayonet slot extends radially through the rear body. One embodiment comprises an outer rear body configured to receive the rear body and a rear part of the front body, wherein the outer rear body has an axial rib provided on its inner surface, the axial rib being configured to restrict movement of the pin in the bayonet slot to maintain the front body and the rear body in a locked state. According to one embodiment the outer rear body has a front flange provided with a radial opening aligned with the mouth of the bayonet slot, the radial opening being configured to receive the pin when the front assembly and rear assembly are assembled or disassembled with each other. The radial opening acts as a guide for the pin into the bayonet slot when the front assembly is being assembled with the rear assembly. According to one embodiment the outer rear body has a release button which in a default position has a radially inwards extending structure configured to prevent axial movement of the pin rearwards in the axial slot, to thereby prevent the front body to move axially rearwards re