Injection device

• US 5,370,629 A
• Filed: 10/13/1993
• Issued: 12/06/1994
• Est. Priority Date: 02/21/1992
• Status: Expired due to Term

• Current Assignee: TecPharma Licensing AG (Ypsomed Holding AG)
• Original Assignee: Medimpex Ets
• Inventors: Kirchhofer, Fritz, Michel, Peter
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US08/133,108
• Time in Patent Office: 419 Days
• Field of Search: 604/207, 604/208, 604/209, 604/210, 604/211, 604/218, 604/232, 604/187
• US Class Current: 604/207
• 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 5/31543 piston rod reset means, i.e. means for causing or facilitating retraction of piston rod to its starting position during cartridge change
• 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

Abstract

The invention concerns an injection device (1) receiving in exchangeable manner an ampoule (4) with a plunger (5) and an injection needle (6). It further comprises an actuation means (7) essentially consisting of an operating head (8), a drive element (11), a guide element (24) and an output member (9, 19) preferably in the form of a rod (9) and flange (19). The output member is non-rotatably affixed to the guide element (11) itself rigidly mounted inside the device (1) and seated by its own thread in an internal thread (27) of the drive element (11) which can be displaced axially and into rotation by the manual operating head (8). When rotating the operating head (8), the output member (9, 19) is advanced and in the process forces forward the plunger (5), the result being injection. The stationary guide element (24) of the disclosed device is located axially ahead of the axially displaceable drive element (11). Accordingly the length of the actuation system (7) is shorter than in state-of-the-art injection devices, whereby a larger maximum dose can be injected with a device (1) of the same length. The device (1) is applicable in medicine.

Claims

1. Injection device to inject particular, selectable quantities of liquid from a liquid receptacle (4), in particular an ampoule (4), fitted with a plunger (5) and comprising a manual, tubular actuation system (7),

comprising an output member (9, 19) displaceable in the direction of advance of the plunger (5), an operating head (8) which can be moved axially and rotationally, further a drive element (11) which can rotate relative to the output member (9, 19) seated inside it, and a guide element (24) for the output member (9, 19)

wherein upon axial displacement of the operating head (8) the drive element (11) is displaceable in the direction of advance of the plunger (5) from a rest position into an end position and back and where this motion is transmitted to the output member (9, 19) connected to the drive element (11),

wherein for the rest position the output member (9, 19) moved away from the plunger (5) by rotating the operating head (8) can be displaced by the drive element (11) in the direction of advance in relation to a plunger stroke required for the related particular quantity of liquid which must be injected without the output member (9, 19) thereby touching the plunger, and

wherein during the transit of the drive element (9, 19) from the rest position to the end position the output member (9, 19) impacts the plunger (5) which is thereby displaced along a pre-set plunger path, characterized in that

the drive element (11) is non-rotatably connected to the operating head (8) and both carry out jointly all their motions,

the guide element (24) is rigidly affixed to the rear part (3) of the device (1),

the output member (9, 19) is non-rotatably supported in the guide element (24),

the guide element (24) is in front of the drive element (11) inside the actuation system (7).

2. Device defined in claim 1, characterized in that the drive element (11) is kept in the rest position by a first spring (16) and is displaceable into the end position against the force of this first spring (16).

3. Device defined in claim 1, characterized in that the output member (9, 19) comprises a rod (9) fitted with a front flange and has planar surfaces (12, 12'"'"') at two mutually opposite sides and elsewhere threaded circular areas (13, 13'"'"').

4. Device defined in claim 1, characterized in that a rotary detent (20) is present between the guide element (24) or parts non-rotatably affixed to it and the drive element (11) or parts non-rotatably affixed to it.

5. Device defined in claim 4, characterized in that the rotary detent (20) is a serrated detent.

6. Device defined in claim 4, characterized in that the parts (21, 22) of the rotary detent (20) are mutually displaceable against springs (16, 35) located either between the nonrotatable parts such as the ampoule holder (29) and the rear part (3) or between rotary parts such as the drive element (11) and the sleeve part (21).

7. Device defined in claim 6, characterized in that the rotational direction of the operating head (8) setting the injection dose is that direction allowing the rotary detent (20) to move with little drag.

8. Device defined in claim 4, characterized in that the rotary detent (20) can be relieved by removing the ampoule (4) from the device (1) in that the ampoule holder (34)--which otherwise presses by means of the spring (35) against the ampoule (4)--is being advanced, whereby the operating head (8) and with it the drive element (11) are rotatable without drag in both directions and the output member (9, 19) thereby is rotatable back into its initial position.