Disposable syringe

• US 4,973,318 A
• Filed: 02/09/1989
• Issued: 11/27/1990
• Est. Priority Date: 02/10/1988
• Status: Expired due to Term

• Current Assignee: DCP AF 1988 A/S Denmark
• Original Assignee: DCP AF 1988 A/S Denmark
• Inventors: Bressendorff, Anders, Thogersen, Klaus, Rex, Jorn, Spork, Allan, Holm, Niels E.
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US07/308,399
• Time in Patent Office: 656 Days
• Field of Search: 604/206, 604/207, 604/208, 604/209, 604/210, 604/211, 604/187, 604/232, 604/236, 604/246, 604/248, 604/192, 604/263, 604/71, 604/72, 604/186, 604/218
• US Class Current: 604/208
• CPC Class Codes: A61M 2005/3126 Specific display means related to dosing
• 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 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/31551 including axial movement of dose setting 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
• CPC Class Codes: A61M 5/3202 Devices for protection of the needle before use, e.g. caps A61M5/50 takes precedence; for infusion spikes A61M5/1626; protectors for sharps A61B50/3001
• CPC Class Codes: A61M 5/50 having means for preventing re-use, or for indicating if defective, used, tampered with or unsterile retractable needles or needle protectors with means for preventing re-use A61M5/321

Abstract

A disposable syringe includes first and second housing elements which are coupled together for rotation without axial movement therebetween. The first housing element receives a cartridge of a solution to be injected, and mounts a liquid outlet needle at its front end. A piston rod is disposed in the second housing element to move axially therein, and this piston rod includes a rod element and a nut element. The rod element is coupled to the first housing element to move axially therein without relative rotation therewith, and the nut element is threaded to the rod element for telescoping movement therewith and is configured to move axially in the second housing element without relative rotation therein. A pressure receiving element is mounted on the nut element. The housing, rod, nut and pressure receiving elements cooperate such that relative rotation between the housing elements in a selected direction causes relative rotation between the nut and rod elements and thereby increases the effective length of the piston rod and causes the pressure receiving element to extend from the second housing element. A protective cap is removably mounted over the first housing element and is configured to abut second housing element while mounted in place on the first housing element. This protective cap is engaged with the first housing element such that rotation of the cap with respect to the second housing element causes rotation of the first housing element with respect to the second housing element.

Claims

1. In a disposable syringe for injecting a number of measured doses of a liquid, of the type comprising first and second housing elements coupled together to allow rotation of the first housing element with respect to the second housing element, said first housing element adapted to receive a quantity of liquid and comprising means for mounting a liquid outlet needle at a front end thereof, said second housing element having a rear end situated opposite the front end of the first housing element, the improvement comprising:

a piston rod disposed in the second housing element to move axially therein, said piston rod comprising a rod element and a nut element, said rod element coupled to the first housing element to move axially therein without relative rotation therewith, said nut element threaded to the rod element for telescoping movement therewith and configured to move axially in the second housing element without relative rotation therein; and

a pressure receiving element on the nut element;

said housing, rod, nut and pressure receiving elements cooperating such that relative rotation between the housing elements in a selected direction causes relative rotation between the rod and nut elements and thereby increases the effective length of the piston rod and causes the pressure receiving element to extend from the second housing element such that a measured quantity of liquid is expressed from the needle when the pressure receiving element is moved back toward the second housing element.

2. The invention of claim 1 wherein the first and second housing elements are coupled together for rotation without axial displacement therebetween.

3. The invention of claim 1 wherein the pressure receiving element defines a first stop surface that limits travel of the nut element inwardly, towards the first housing element.

4. The invention of claim 2 wherein the nut element defines an axially oriented scale positioned to indicate the axial position of the nut element with respect to the second housing element.

5. The invention of claim 4 wherein the scale is integrally formed on the nut element.

6. The invention of claim 1 wherein the first housing element is configured to receive a cartridge having a pierceable diaphragm at a front end thereof, a slideable piston at a rear end thereof, and containing the quantity of liquid.

7. The invention of claim 2 wherein the nut element defines at least one radially protruding, axially extending projection on an exterior portion thereof, and wherein the projection is received in an axially extending groove in an inner portion of the second housing element.

8. The invention of claim 1 wherein the nut element comprises a second stop surface configured to contact the second housing element to limit axial movement of the nut element out of the second housing element.

9. The invention of claim 1 wherein the nut element and the pressure receiving element are substantially axially symmetrically shaped, and wherein the pressure receiving element defines an outer diameter substantially equal to that of the second housing element.

10. The invention of claim 1 further comprising

a removable protective cap configured to receive the first housing element and substantially abut the second housing element while mounted on the first housing element;

and

means for releasably coupling the protective cap and the first housing element for rotation together such that rotation of the protective cap with respect to the second housing element causes rotation of the first housing element with respect to the second housing element.

11. The invention of claim 10 wherein the substantially abutting front portion of the second housing element and rear portion of the protective cap together comprise scale means for measuring relative rotation of the protective cap with respect to the second housing element.

12. The invention of claim 11 further comprising means for providing detents at selected rotational positions of the first housing element with respect to the second housing element.

13. The invention of claim 12 wherein the coupling means allows the protective cap to receive the first housing element in multiple different angular positions of the protective cap with respect to the first housing element to allow the protective cap to be oriented at a selected position with respect to the second housing element, regardless of the detent rotational position of the first housing element in the second housing element.

14. The invention of claim 10 wherein the substantially abutting front portion of the second housing element and rear portion of the protective cap together comprise interlocking means for defining a selected angular position of the protective cap with respect to the second housing element.

15. The invention of claim 14 wherein the interlocking means comprises a recess on the rear portion of the protective cap and a projection on the front portion of the second housing element, said projection shaped to fit into the recess to define the selected angular position.

16. The invention of claim 1 wherein the rod element defines at least one toothed axial groove, and wherein the rod element is coupled to the first housing element by at least one pawl that rides in the groove to prevent rotation of the rod element in the first housing element, said pawl engaging the toothed groove to prevent retraction of the rod element.

17. The invention of claim 16 wherein the at least one groove in the rod element comprises two diametrically opposed grooves, and wherein the at least one pawl comprises two pawls, one riding in each of the grooves.

18. The invention of claim 16 wherein the liquid is contained in a cartridge and wherein the first housing element comprises a locking ring that snaps in place to lock the cartridge within the first housing element.

19. The invention of claim 18 wherein the locking ring mechanically interlocks with a mating portion of the first housing element to prevent rotation therebetween.

20. In a disposable syringe for injecting a number of measured doses of a liquid, of the type comprising first and second housing elements coupled together to allow rotation of the first housing element with respect to the second housing element, said first housing element adapted to receive a quantity of liquid and comprising means for mounting a liquid outlet needle at a front end thereof, said second housing element having a rear end situated opposite the front end of the first housing element, the improvement comprising:

a piston rod disposed in the second housing element to move axially therein, said piston rod comprising a piston actuating end and a force receiving end, said force receiving end positioned at the rear end of the second housing element when in an initial position;

means, responsive to relative rotation between the first and second housing elements, for causing the force receiving end of the piston rod to move away from the initial position to preset a dose to be delivered through the needle when the force receiving end is returned to the initial position;

a protective cap removably mounted over the front end of the first housing element to protect the needle; and

means for releasably coupling the protective cap and the first housing element for rotation together such that rotation of the protective cap with respect to the second housing element causes rotation of the first housing element with respect to the second housing element.

21. The invention of claim 20 wherein the protective cap is configured to receive the first housing element such that a front portion of the second housing element substantially abuts a rear portion of the protective cap when the protective cap is mounted in place over the first housing element.

22. The invention of claim 21 wherein the substantially abutting front portion of the second housing element and rear portion of the protective cap together comprise scale means for measuring relative rotation of the protective cap with respect to the second housing element.

23. The invention of claim 22 wherein the scale means comprises a circumferential scale on the rear portion of the protective cap and a marker on the front portion of the second housing element.

24. The invention of claim 20 wherein the releasably coupling means comprises a set of interengaging splines on the protective cap and the first housing element.

25. The invention of claim 24 wherein the splines are configured to allow the protective cap to receive the first housing element in multiple different angular positions of the protective cap with respect to the first housing element.

26. The invention of claim 21 wherein the substantially abutting front portion of the second housing element and rear portion of the protective cap together comprise interlocking means for defining a selected angular position of the protective cap with respect to the second housing element.

27. The invention of claim 26 wherein the interlocking means comprises a recess on the rear portion of the protective cap and a projection on the front portion of the second housing element, said projection shaped to fit into the recess to define the selected angular position.

28. The invention of claim 20 wherein the piston rod comprises a rod element and a nut element threadedly engaged with the rod element, and wherein the nut element is configured to move axially without rotating in the second housing element.

29. The invention of claim 28 further comprising ratchet means for preventing the rod element from retracting from the first housing element while allowing the rod element to move into the first housing element.

30. The invention of claim 20 wherein the first housing element is configured to receive a cartridge having a pierceable diaphragm at a front end thereof, a slideable piston at a rear end thereof, and containing the quantity of liquid.