Injection device

• US 5,591,136 A
• Filed: 10/27/1995
• Issued: 01/07/1997
• Est. Priority Date: 04/15/1991
• Status: Expired due to Term

• Current Assignee: B D Medico SARL
• Original Assignee: Medico Development Investment Company
• Inventors: Gabriel, Jochen
• Primary Examiner(s): McDermott, Corrine M.
• Assistant Examiner(s): STRIGHT, RONALD K
• Application Number:
  US08/549,641
• Time in Patent Office: 438 Days
• Field of Search: 604/207-211, 604/186, 604/187, 604/218, 604/220, 604/224, 604/232, 604/234, 222/287, 222/309, 222/325, 222/326, 222/327, 222/336, 222/340, 222/391, 222/137
• US Class Current: 604/211
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• CPC Class Codes: A61M 5/31538 Permanent blocking, e.g. by medical personnel
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31563 interacting with a displaceable stop member
• CPC Class Codes: A61M 5/3158 performed by axially moving actuator operated by user, e.g. an injection button
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

A safety injection device, such as a hypodermic needle, for dispensing liquid from a cartridge in quantities determined by the length of a plunger which may be selectively adjusted in one position only of the plunger. The plunger comprises first and second threadedly connected sections cooperating with a connector which may be selectively activated when the plunger is moved into the one position to permit rotation of one plunger section relative to the other. Preferably, the adjustment position of the plunger coincides with its positions assumed in preparation of an injection stroke, with the connector preferably providing for undirectional rotation of the one plunger section.

Claims

1. An injection device for injecting adjustable dose of an injection liquid (13), comprising:

a housing (11,

     21) having a space therein for receiving a container (12) having a piston (14) displaceably arranged therein and containing the injection liquid (13);

an adjustable-length plunger (29,

     38) in said housing, said plunger being axially displaceable in said housing between a first dosage-setting axial position and a second axial position;

said plunger acting upon the piston (14) in the container (12) when said plunger moves from said first dosage setting axial position to said second axial position thereof;

said plunger (29,

     38) comprising adjustment means for selectively adjusting the effective length of said plunger, said plunger and adjustment means including a threaded member (38);

a threaded spindle (29) guided in an interior thread (35) of said threaded member (38);

a guide member (34) rotatably connected to said threaded member;

means (30, 31,

     36) arranged between said guide member and said threaded spindle (29) for axially guiding said threaded spindle and for preventing rotation of said threaded spindle relative to said guide member (34);

enabling/disabling means (55,

     56) automatically enabling said adjustment means when said plunger is in said first dosage setting axial position and automatically disabling said adjustment means when said plunger is in said second axial position, said enabling/disabling means being operatively arranged between said plunger (29,

     38) and said housing (11,

     21) and responsive to the axial position of said plunger relative to said housing,

whereby adjustment of the effective length of said plunger by said adjustment means is automatically disabled when said plunger is in said second axial position.

2. The injection device of claim 1, comprising a control member (23) coupled to said adjustable-length plunger for at least one of rotating and axially displacing said plunger.

3. The injection device of claim 2, wherein said control member is manually operable.

4. The injection device of claim 2, further comprising a stop member (76) operatively connected in said housing (22, 21) and arranged to limit rotation of said control member (23) to an extent proportional to a predetermined dose of injection fluid.

5. The injection device of claim 1, wherein said enabling/disabling means (55, 56) includes means for preventing rotation of said guide member (34) in said first position of said plunger and for enabling rotation of said guide member in said second position of said plunger.

6. The injection device of claim 5, wherein said enabling/disabling means provides, in said first position of said plunger, a force-locking connection between said housing and said guide member (34) to prevent relative rotation therebetween.

7. The injection device of claim 5, wherein said enabling/disabling means comprises one of a first and a second complementary engaging means (55, 56) provided on said guide member (34), and the other of said first and second complementary engaging means provided on said housing, said first and second complementary engaging means engaging with each other when said plunger is in the first axial position thereof.

8. The injection device of claim 1, further comprising restricting means (60, 66) arranged in said housing (11, 21) and coupled between said housing and said plunger (29, 38) for restricting axial displacement of said plunger from said second position to said first position, when said plunger is in a predetermined rotational position relative to said housing.

9. The injection device of claim 8, wherein said restricting means (60, 66) is disabled during movement of said plunger from said first position to said second position thereof.

10. The injection device of claim 1, wherein means (48, 49) is provided between said threaded member (38) and said guide member (34) for preventing unintentional relative rotation therebetween.

11. The injection device of claim 10, wherein said means for preventing said unintentional relative rotation comprises a ratchet-pawl arrangement (48, 49) coupled between said threaded member (38) and said guide member (34).

12. The injection device of claim 1,

wherein said enabling/disabling means comprises rotation control means, said rotation control means, when the enabling/disabling means are in an enabled state, preventing rotation of said adjusting element relative to said housing and further comprises positional control means, controlled by the axial position of said plunger (29, 38) relative to said housing (11, 21), enabling said rotation control means when said plunger is in said first dosage setting axial position and for disabling said rotation control means when said plunger is in said second axial position, said adjusting element being freely rotatable in said housing when said plunger (29, 38) is in said second axial position.

13. The injection device of claim 1, comprising rotation limiting means provided between said threaded member (38) and said guide member (34) for limiting relative rotation therebetween to one direction.

14. An injection device for injecting an adjustable dose of an injection liquid, comprising:

a housing (11,

     21) having a space therein for receiving a container (12) having a piston (14) displaceably arranged therein and containing the injection liquid (13);

setting means for setting a dose to be injected, said setting means being connected to an adjustable-length plunger (29,

     38), said plunger being axially bidirectionally displaceable within said housing between a first axial position of said plunger and a second axial position of said plunger;

said plunger acting upon the piston (14) in the container;

said plunger comprising length adjustment means responsive to application of a predetermined torque thereto for adjusting the effective length of said plunger including

a threaded member (38);

a threaded spindle (29) guided in an interior thread (35) of said threaded member (38);

a guide member (34) rotatably connected to said threaded member;

means (30, 31,

     36) arranged between said guide member and said threaded spindle for axially guiding said threaded spindle and for preventing rotation of said threaded spindle relative to said guide member; and

means (55,

     56) operatively arranged between said guide member (34) and said housing and responsive to the axial position of said guide member (34) relative to said housing for preventing rotation of said guide member (34) relative to said housing in said first axial position of said plunger to enable application of a user-supplied torque between said threaded member (38) of the length adjustment means and said housing in said first position, and

for enabling rotation of said guide member (34) relative to said housing in said second axial position of said plunger for automatically preventing application of the user-supplied torque between said threaded member of said length adjustment means and said housing when said plunger is in said second axial position,

whereby length-adjustment of said plunger is automatically disabled when said plunger is in said second axial position.

15. The injection device of claim 14, comprising a control member (23) coupled to said adjustable-length plunger for at least one of rotating and axially displacing said plunger.

16. The injection device of claim 15, wherein said control member is manually operable.

17. The injection device of claim 15, comprising a stop member (76) operatively connected in said housing (11, 21) and arranged to limit rotation of said control member (23) to an extent proportional to a predetermined dose of injection fluid.

18. The injection device of claim 14, wherein means (48, 49) is provided between said threaded member (38) and said guide member (34) for preventing unintentional relative rotation therebetween.

19. The injection device of claim 18, wherein said means for preventing said unintentional relative rotation comprises a ratchet-pawl arrangement (48, 49) coupled between said threaded member (38) and said guide member (34).

20. The injection device of claim 14, further comprising restricting means (60, 66) arranged in said housing and coupled between said housing and said plunger for restricting axial displacement of said plunger from said second position to said first position, when said plunger is in a predetermined rotational adjustment position relative to said housing.

21. The injection device of claim 20, wherein said restricting means (60, 66) is disabled during movement of said plunger from said first axial position to said second axial position thereof.

22. The injection device of claim 14, wherein said means operatively arranged between the plunger and the housing for axially guiding the threaded spindle (29) provides, in said first position of said plunger, a force-locking connection preventing relative rotation between said housing (11, 21) and said guide member (34).

23. The injection device of claim 14, wherein said means operatively arranged between the plunger and the housing for axially guiding the threaded spindle (29) comprises a first and a second complementary engaging means (55, 56), one (55) of said engaging means being provided on said guide member (34), and the other (56) of said complementary engaging means being provided on said housing (21), said first and second complementary engaging means engaging with each other when said plunger (29, 38) is in the first axial position thereof.

24. The injection device of claim 14, comprising rotation limiting means provided between said threaded member (38) and said guide member (34) for limiting relative rotation therebetween to one direction.

25. An injection device for injecting an adjustable dose of a liquid, comprising:

a housing (11,

     21) having a space therein for receiving a container (12) having a piston (14) displaceably arranged therein and containing the liquid (13);

an adjustable-length plunger (29,

     38) positioned in said housing, said plunger being axially displaceable in said housing between two axial terminal positions relative to said housing, said plunger (29,

     38) being axially aligned with, operatively coupled to, and acting upon the piston (14) in the container (12) upon said axial displacement thereof in a direction toward said container;

said plunger (28,

     38) comprising;

a threaded member (38),

a threaded spindle (29) guided in an interior thread (35) of said threaded member (38),

a guide member (34) rotatably connected to said threaded member, and

means (30, 31,

     36) arranged between said guide member and said threaded spindle for preventing rotation of said threaded spindle relative to said guide member while permitting axial movement therebetween; and

means operatively arranged between said guide member (34) and said housing (11,

     21) and controlled by the axial position of said plunger (29,

     38) relative to said housing for establishing a torque-transferring connection between said guide member (34) and said housing in one of said terminal positions of said plunger, and for interrupting said torque-transferring connection in another one of said terminal positions of said plunger.

26. The injection device of claim 25, wherein means (48, 49) is provided between said threaded member (38) and said guide member (34) for preventing unintentional relative rotation therebetween.

27. The injection device of claim 26, wherein said means for preventing said unintentional relative rotation comprises a ratchet-pawl arrangement (48, 49) coupled between said threaded member (38) and said guide member (34).

28. The injection device of claim 25, comprising restricting means (60, 66) coupled between said housing (12, 21) and said plunger (29, 38) for restricting axial displacement of said plunger from a second terminal position of said plunger to a first terminal position of said plunger, when said plunger is in a predetermined rotational position relative to said housing.

29. The injection device of claim 28, wherein said restricting means (60, 66) is adapted to be disabled during movement of said plunger (29, 38) from said first terminal position to said second terminal position thereof.

30. The injection device of claim 25, comprising a control member (23) coupled to said adjustable-length plunger for at least one of rotating and axially displacing said plunger.

31. The injection of claim 30, wherein said control member is manually operable.

32. The injection device of claim 25, comprising rotation limiting means provided between said threaded member (38) and said guide member (34) for limiting relative rotation therebetween to one direction.