Relating to automatic injection devices
First Claim
Patent Images
1. An injection device comprising:
- a housing;
a syringe coupled to a needle at one end and having a syringe barrel with an inner circular circumference, the syringe slideably mounted within the housing for movement between a first position relative to the housing in which the needle is shrouded by the housing and a second position relative to the housing in which the needle projects from the housing;
a bung slideably mounted in the syringe and moveable to expel a liquid through the needle;
a plunger comprising;
an upper solid portion having a circular cross-sectional profile,a lower solid portion having a distal end operable to move a bung and to transmit an expulsion force thereto, the lower solid portion having a circular cross-sectional profile, anda collapsible projecting portion comprising two flexible elbows on either side of a central void extending along a central axis of the plunger between the upper and lower solid portions, wherein the flexible elbows project outwardly from the central void when the projecting portion is in a projecting position, and wherein the flexible elbows are inwardly collapsible toward the central void to fit within the inner circular circumference of the syringe barrel when the projecting portion is in a collapsed position; and
an actuating bias member provided at one end of the housing and operable to move the plunger toward another end of the housing.
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0 Petitions
Accused Products
Abstract
An injection device comprises a syringe extendible against a spring bias from a retracted position in a housing to a projecting injecting position. A spring biased plunger has collapsible elbows 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.
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Citations
21 Claims
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1. An injection device comprising:
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a housing; a syringe coupled to a needle at one end and having a syringe barrel with an inner circular circumference, the syringe slideably mounted within the housing for movement between a first position relative to the housing in which the needle is shrouded by the housing and a second position relative to the housing in which the needle projects from the housing; a bung slideably mounted in the syringe and moveable to expel a liquid through the needle; a plunger comprising; an upper solid portion having a circular cross-sectional profile, a lower solid portion having a distal end operable to move a bung and to transmit an expulsion force thereto, the lower solid portion having a circular cross-sectional profile, and a collapsible projecting portion comprising two flexible elbows on either side of a central void extending along a central axis of the plunger between the upper and lower solid portions, wherein the flexible elbows project outwardly from the central void when the projecting portion is in a projecting position, and wherein the flexible elbows are inwardly collapsible toward the central void to fit within the inner circular circumference of the syringe barrel when the projecting portion is in a collapsed position; and an actuating bias member provided at one end of the housing and operable to move the plunger toward another end of the housing. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A syringe assembly comprising:
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a syringe having a distal end couplable to a needle, a proximal end and a syringe barrel having an inner circular circumference; a bung slideably mounted in the syringe; and a plunger comprising; an upper solid portion having a circular cross-sectional profile, a lower solid portion having a distal end insertable into the proximal end of the syringe and operable to move the bung and to transmit an expulsion force thereto, the lower solid portion having a circular cross-sectional profile and an outer circumference, and a collapsible projecting portion comprising two flexible elbows on either side of a central void extending along a central axis of the plunger between the upper and lower solid portions, wherein the flexible elbows project outwardly from the central void in a projecting position and have an outer circumference greater than the inner circular circumference of the syringe barrel, and wherein the flexible elbows are inwardly collapsible toward the central void to fit within the inner circular circumference of the syringe barrel when the projecting portion is in a collapsed position. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A syringe plunger, comprising:
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an upper solid portion having a circular cross-sectional profile; a lower solid portion having a circular cross-sectional profile and a distal end operable to move a bung in a syringe barrel and to transmit an expulsion force thereto; and a collapsible projecting portion comprising two flexible elbows on either side of a central void extending along a central axis of the syringe plunger between the upper and lower solid portions, wherein the flexible elbows project outwardly from the central void in a projecting position and have an outer circumference greater than an inner circumference of the syringe barrel, wherein the flexible elbows are inwardly collapsible toward the central void when the projecting portion is in a collapsed position and the outer circumference of the projecting portion fits within the inner circumference of the syringe barrel. - View Dependent Claims (14, 15, 16)
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17. A syringe assembly, comprising:
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a housing of an automatic injection device; a syringe couplable to a needle at a distal end, the syringe slideably mounted within the housing for movement between a shrouded retracted position relative to the housing and an extended injecting position relative to the housing; a bung slideably mounted in the syringe and moveable to expel a liquid dose through the needle at the distal end of the syringe; a plunger having an end operable to move the bung and to transmit an expulsion force thereto; and wherein the plunger is provided with a projecting region which is outside the syringe when the plunger is at a first position but which in use, on movement away from the first position, engages a proximal end of the syringe to drive the syringe to the extended injecting position, whereupon arresting of further movement of the syringe causes the projecting region to collapse inwardly so that it enters the syringe to allow the plunger to expel the liquid dose. - View Dependent Claims (18, 19, 20, 21)
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Specification