| 主权项 |
1. 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; anda 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. |
