Injection device
First Claim
1. A device for delivering a plurality of preselected doses of a liquid drug from a loaded liquid reservoir (3), co-axially abutting against a plunger (5) at its upper end and a needle holder (7) at its lower end, having a first housing member (2) to accommodate the liquid reservoir (3) and a second housing member (1) coaxially and telescopically movably connected relative to the first housing member (2), and a drive stem (39) connected on the axis (36) of the device for reciprocal movement forward and backward exclusively by the same stroke distance l1 moveable into contact with the plunger (5) to cause the plunger (5) to advance to deliver doses of liquid from the liquid reservoir through the needle holder, the improvement comprising:
- means (11, 30, 32, 31, 35, 44, 29, 42, 50,) connected in said second housing member (1) and connected (9, 50, 25,
26) for rotative movement to both said first and second housing members (2,
1) to move the first and second housing members (2,
1) into each other by a selectable axial path lx ;
said means including push button means (11, 30, 32,
31) connected for reciprocal movement in said second housing member (1) and said means (11, 30, 32, 31, 35, 66, 29, 42,
50) and having a portion (11,
30) projecting from said second housing member (1);
said drive stem (39) connected at one end to said push button means (11, 30, 32,
31) and connected for reciprocal movement in said means (11, 30, 32, 31, 35, 44, 29, 42
50) to position the opposite end (41) of said drive stem (39) relative to the plunger (5) at an axial distance corresponding to the stroke path l1, and the opposite end (41) of said drive stem (39) extending from said means (11, 30, 32, 31, 35, 44, 29, 42,
50) into said first housing member (2) adjacent said plunger 5, whereby rotation of said means (11, 30, 32, 31, 35, 44, 29, 42,
50) by said push button means (11) by a selected amount moves said first housing member (2) into said second housing member (1) by a selected axial distance lx corresponding to the selected dose to be delivered thereby reducing the preset axial distance l1 between said opposite end (41) of the drive stem (39) and the plunger (5) to l1 -lx and causing the plunger (5) to be axially advanced by the amount of lx only upon reciprocally moving the drive stem (39) along its stroke path l1 by said push button means (11).
1 Assignment
0 Petitions
Accused Products
Abstract
A prefilled syringe (3) with plunger (5) is arranged in the lower housing member (2) of the injection device, and a drive stem (39) for the advancement of the plunger is supported in the upper housing member (1), this drive stem being advanceable by a specific stroke (11) by means of a knob (11) and being retractable by the same stroke (11) by means of a spring (49). The two housing members (1, 2) can be telescoped by means of a helical gear mechanism (9, 50) approximately by the entire advancement path (13) of the plunger (5) within the ampoule (3). The amount of fluid to be injected in each case is determined by the respective extent of telescoping of the two housing members (1, 2).
The length of the injection device is a measure for the content of the ampoule (3) so that the user, without giving special attention, will recognize when the liquid reservoir is running low by the feature that the device becomes increasingly shorter with progressive injections.
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Citations
10 Claims
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1. A device for delivering a plurality of preselected doses of a liquid drug from a loaded liquid reservoir (3), co-axially abutting against a plunger (5) at its upper end and a needle holder (7) at its lower end, having a first housing member (2) to accommodate the liquid reservoir (3) and a second housing member (1) coaxially and telescopically movably connected relative to the first housing member (2), and a drive stem (39) connected on the axis (36) of the device for reciprocal movement forward and backward exclusively by the same stroke distance l1 moveable into contact with the plunger (5) to cause the plunger (5) to advance to deliver doses of liquid from the liquid reservoir through the needle holder, the improvement comprising:
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means (11, 30, 32, 31, 35, 44, 29, 42, 50,) connected in said second housing member (1) and connected (9, 50, 25,
26) for rotative movement to both said first and second housing members (2,
1) to move the first and second housing members (2,
1) into each other by a selectable axial path lx ;said means including push button means (11, 30, 32,
31) connected for reciprocal movement in said second housing member (1) and said means (11, 30, 32, 31, 35, 66, 29, 42,
50) and having a portion (11,
30) projecting from said second housing member (1);said drive stem (39) connected at one end to said push button means (11, 30, 32,
31) and connected for reciprocal movement in said means (11, 30, 32, 31, 35, 44, 29, 42
50) to position the opposite end (41) of said drive stem (39) relative to the plunger (5) at an axial distance corresponding to the stroke path l1, and the opposite end (41) of said drive stem (39) extending from said means (11, 30, 32, 31, 35, 44, 29, 42,
50) into said first housing member (2) adjacent said plunger 5, whereby rotation of said means (11, 30, 32, 31, 35, 44, 29, 42,
50) by said push button means (11) by a selected amount moves said first housing member (2) into said second housing member (1) by a selected axial distance lx corresponding to the selected dose to be delivered thereby reducing the preset axial distance l1 between said opposite end (41) of the drive stem (39) and the plunger (5) to l1 -lx and causing the plunger (5) to be axially advanced by the amount of lx only upon reciprocally moving the drive stem (39) along its stroke path l1 by said push button means (11). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification