Automatic Injection Devices
2 Assignments
0 Petitions
Accused Products
Abstract
An injection device comprises a syringe (1) extendible against a spring bias (9) from a retracted position in a housing (2) to a projecting injecting position. A spring biased plunger has collapsible elbows (10) which, when the plunger is released, initially engage the end of the syringe to drive it to the projecting position, whereupon arresting of the syringe movement causes the elbows to collapse inside the syringe to allow the plunger to engage and drive the bung (3).
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Citations
20 Claims
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1-7. -7. (canceled)
- 8. An injection device for causing a dose of liquid to be ejected from a needle at one end of a syringe (1) located within a housing (2) of the device, the syringe containing a moveable bung (4) and the syringe being movable by a plunger (7), upon release of an actuating bias member (8) at one end of the housing (2), to move the syringe (1), from a first position wherein the needle (5) is shrouded by the housing (2), to a second position wherein the needle projects from the other end of the housing, the plunger being in the form of a rod with a longitudinally centrally located flexible projecting portion (10) which, prior to release of said actuating bias member, is situated beyond the other end (6) of the syringe (1) and initially spaced from the bung (4), such that a primary movement of the plunger (7), under the bias of the actuating bias member (8), will cause the projecting portion (10) to bear against the other end (6) of the syringe such that the syringe is moved from said first to said second position, whereupon arresting of further movement of the syringe, results in the flexible portion (10) collapsing inwardly so that it enters the syringe, thus enabling the plunger (7) to move by a secondary movement, within the syringe, into contact with and to act upon said bung (4) to compress the liquid within the syringe and cause expression of the liquid through the syringe needle (5).
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14. An injection device comprising:
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a housing (2); a syringe (1) slideably mounted within said housing for movement between a shrouded retracted position and an extended injecting position; a bung (4) slideably mounted in said syringe (1) and moveable to expel a liquid dose through a needle (5) at the distal end of the syringe; a plunger (7) having an end initially spaced from, but operable to engage said bung (4) and to transmit an expulsion force thereto, and a bias spring (8) operable to move said plunger from a first position to a second position, characterised in that said plunger is provided with at least one integrally formed collapsible projecting region (10) which is outside said syringe when said plunger (7) is at its first position but which in use on movement away from said first position engages the proximal end (6) of said syringe (1) to drive it to its extended position whereupon arresting of further movement of said syringe (1) causes said collapsible projecting region (10) to collapse inwardly so that it enters the syringe to allow said plunger to engage said bung (4) and expel a liquid dose.
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Specification