Safety needle syringe braking system
AssigneeCredence Medsystems, Inc.
InventorRichard B. Oliver
Life of this patent
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Abstract
A braking mechanism for a retractable safety syringe is disclosed herein. In a first embodiment, the braking mechanism is disposed about the distal end of a piston. The braking mechanism may comprise a friction material about a post attached to a piston. The friction material is displaced from a seat to a landing when the piston is traversed to a fully extended position to disengage the braking mechanism. In a second embodiment, the braking mechanism is disposed at a proximal end of a syringe body. The braking mechanism has a friction member which engages an outer surface of a rigid shaft of a plunger. The friction member is selectively pivotable to disengage the braking mechanism.
Claims15
A retractable safety syringe for preventing syringe reuse and accidental needle pricking, the syringe comprising:
- a syringe body defining a distal end, proximal end and inner surface;
- a plunger having a piston disposed within the syringe body, a rigid shaft extending through the proximal end of the syringe body, and a thumb platform attached to the rigid shaft which is operative to traverse the piston between a retracted position and a fully extended position, the piston further having a braking mechanism comprising;
- a protuberance having a seat and a landing, an outer periphery of the seat being larger than the outer periphery of the landing;
- a friction material disposable about the seat or the landing, a maximum friction force between the friction material and the inner surface of the body being greater than or about equal to a retraction force of to retraction mechanism when the friction material is disposed about the seat, and the friction force between the friction materials and the inner surface of the body being less than the retraction force when the friction material is disposed about the landing;
- and
- a punch attached to the distal end of the body and operative to displace the friction material from the seat to the landing when the piston is traversed to the fully extended position.
A retractable safety syringe for preventing syringe reuse and accidental needle pricking, the syringe comprising:
- a syringe body defining a distal end and a proximal end;
- a plunger having a piston disposed within the syringe body, a rigid shaft extending through the proximal end of the syringe body and a thumb platform attached to the rigid shaft which is operative to traverse the piston between a retracted position, a first extended position, and a second extended, the plunger being biased toward the retracted position via a retraction mechanism;
- a braking mechanism adjacent the proximal end of the syringe body, the braking mechanism comprising:
- a friction member having a through hole, the rigid shaft slidably disposed through the through hole, the friction member having an up position and a down position, an inner edge of the through hole frictionally engages the rigid shaft to resist a retraction force of the retraction mechanism that urges the plunger to the retracted position when the friction member is in the up position and the inner edge of the through hole frictionally disengages the rigid shaft when the friction member is in the down position to permit the retraction force to urge the plunger to the retracted position.
Dependencies are inferred from the claim text.