Injection device
First Claim
1. An injection device including:
- a housing for containing a syringe having a bore extending from an end surface, a needle communicating with the bore through the end surface and a dispensing piston movable in said bore towards said end surface so as to expel the contents of the syringe through the needle, the housing having an opening at one end through which the needle may extend;
a resilient member for biassing the syringe and needle inwardly of the housing;
a drive element movable towards said one end so as to move the needle of the syringe out of the opening and to move the dispensing piston of the syringe towards the end surface;
a mechanism operable to release the syringe such that the needle moves inwardly of the housing;
a drive coupling for extending from said drive element to the dispensing piston of the syringe so as to transfer movement of said drive element to the dispensing piston;
wherein the drive coupling is compressible in length such that, after the drive element has moved the dispensing piston to the end surface, the drive coupling gradually reduces in length and transfers sufficient force to maintain the needle in its extended position whilst the dispensing piston is maintained at the end surface until said mechanism releases the syringe.
4 Assignments
0 Petitions
Accused Products
Abstract
An injection device is for use with a syringe having a bore extending from an end surface, a needle communicating with the bore through the end surface and a dispensing piston movable in the bore towards the end surface. The injection device includes a housing having an opening, a resilient member for biasing the syringe and needle inwardly of the housing, a drive element movable towards the one end so as to move the needle out of the opening against the bias of the resilient member, a delatch mechanism operable to release the syringe such that the needle moves inwardly of the housing, and a drive coupling. The drive coupling gradually reduces in length such that, after the drive element has moved the dispensing piston to the end surface, the drive element continues to move to the dispensing piston at the end surface.
33 Citations
57 Claims
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1. An injection device including:
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a housing for containing a syringe having a bore extending from an end surface, a needle communicating with the bore through the end surface and a dispensing piston movable in said bore towards said end surface so as to expel the contents of the syringe through the needle, the housing having an opening at one end through which the needle may extend; a resilient member for biassing the syringe and needle inwardly of the housing; a drive element movable towards said one end so as to move the needle of the syringe out of the opening and to move the dispensing piston of the syringe towards the end surface; a mechanism operable to release the syringe such that the needle moves inwardly of the housing; a drive coupling for extending from said drive element to the dispensing piston of the syringe so as to transfer movement of said drive element to the dispensing piston; wherein the drive coupling is compressible in length such that, after the drive element has moved the dispensing piston to the end surface, the drive coupling gradually reduces in length and transfers sufficient force to maintain the needle in its extended position whilst the dispensing piston is maintained at the end surface until said mechanism releases the syringe. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 16, 17, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 55, 56)
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11. An injection device according to claim I wherein the drive coupling includes:
a drive frictional surface engaging a driven frictional surface, the drive frictional surface being movable by said drive element and said driven frictional surface being operable to move the dispensing piston such that when the dispensing piston reaches the end surface the drive frictional surface slips relative to the driven frictional surface. - View Dependent Claims (12, 13)
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20. A drive coupling for use in an injection device, wherein the injection device comprises a housing for containing a syringe having a bore extending from an end surface, a needle communicating with the bore through the end surface and a dispensing piston movable in said bore towards said end surface so as to expel the contents of the syringe through the needle, the housing having an opening at one end through which the needle may extend;
- a resilient member for biassing the syringe and needle inwardly of the housing;
a drive element movable towards said one end so as to move the needle of the syringe out of the opening and to move the dispensing piston of the syringe towards the end surface;
a mechanism operable to release the syringe such that the needle moves inwardly of the housing;
a drive coupling for extending from said drive element to the dispensing piston of the syringe so as to transfer movement of said drive element to the dispensing piston;
wherein the drive coupling is compressible in length such that, after the drive element has moved the dispensing piston to the end surface, the drive coupling gradually reduces in length and transfers sufficient force to maintain the needle in its extended position whilst the dispensing piston is maintained at the end surface until said mechanism releases the syringe, wherein the drive coupling having;a length for extending from the drive element to the dispensing piston of the syringe so as to transfer movement of the drive element to the dispensing piston; wherein the drive coupling is compressible in length whilst overcoming the bias of the resilient member such that, after the drive element has moved the dispensing piston to the end surface, the drive coupling gradually reduces in length whilst the dispensing piston is maintained at the end surface until the mechanism releases the syringe. - View Dependent Claims (57)
- a resilient member for biassing the syringe and needle inwardly of the housing;
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22. An injection device including:
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a housing for containing a syringe having a bore extending in a syringe body from an end surface, a needle communicating with the bore through the end surface and a dispensing piston movable in said bore towards said end surface so as to expel the contents of the syringe through the needle, the housing having an opening at one end through which the needle may extend; a resilient member for biassing the syringe and needle inwardly of the housing; a drive element movable towards said one end so as to move the needle of the syringe out of the opening and to move the dispensing piston of the syringe towards the end surface; a drive coupling for extending from said drive element to the dispensing piston of the syringe so as to transfer movement of said drive element to the dispensing piston, wherein the drive coupling maintains direct connection between the drive element to the dispensing piston; and an engagement for transferring drive directly from the drive coupling to the syringe body such that movement of the drive element towards said one end causes no relative movement of the dispensing piston in the syringe; wherein the engagement is releasable once the needle of the syringe extends out of the opening such that movement of the drive element towards said one end causes relative movement of the dispensing piston in the syringe body. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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Specification