초록 ▼

A locking assembly for the plunger of a syringe locks the plunger head inside the body of the syringe when the plunger is depressed at the end of an injection cycle. The inner wall of the syringe body has a constriction which projects inwardly toward the center. The head of the plunger has a catch a

A locking assembly for the plunger of a syringe locks the plunger head inside the body of the syringe when the plunger is depressed at the end of an injection cycle. The inner wall of the syringe body has a constriction which projects inwardly toward the center. The head of the plunger has a catch adapted to cooperate with the constriction and hook the plunger when the plunger is depressed. A flexible shield or seal member is mounted on the plunger head adjacent the catch to prevent trapping of air bubbles under the catch during movement of the plunger while the syringe is being filled with injection fluid and readied for use. The locking assembly is particularly suited for use with a retractable syringe design.

대표청구항 ▼

In a syringe having a hollow syringe body elongated longitudinally between a front tip end and a back end, raid syringe body having an inner wall surface, a front portion and a hollow back portion, an exposed injection needle in fluid communication with the hollow back portion of the syringe body, a

In a syringe having a hollow syringe body elongated longitudinally between a front tip end and a back end, raid syringe body having an inner wall surface, a front portion and a hollow back portion, an exposed injection needle in fluid communication with the hollow back portion of the syringe body, a movable plunger having a head end disposed within the hollow syringe body and a sliding seal mounted on the plunger head in sliding contact with the inner wall surface to define a variable chamber for injection fluid in the back portion of the syringe body behind the front portion thereof whereby injection fluid may be passed through the needle upon movement of the plunger, wherein the improvement is a syringe having an improved locking assembly comprising: a constriction being located on the inner wall surface of the syringe body; the head of the plunger having a catch adapted to cooperate with said constriction to hook the plunger when the plunger is depressed to complete an injection and thereby lock the plunger in the syringe body, said catch comprising a plurality of resilient fingers which serve to engage said constriction in response to depression of the plunger at the end of an injection cycle; and a flexible shield adjacent the catch on the plunger head to prevent trapping bubbles under the catch during movement of the plunger while the syringe is being filled with injection fluid and readied for use.