Merit Medical Systems, Inc.

Fred P Lampropolous

William Padilla

Jerrold L Foote

Darla R Gill

A syringe and method for use which may be selectively operated between a free position and a locked position. A triggering device configured with a trigger attached to the plunger of the syringe is employed. The triggering device includes a set of threads located on the plunger and a corresponding set of threads on the barrel of the syringe. Upon actuation of the trigger, the threads on the plunger are retracted from their position of engagement with the threads on the barrel, thereby placing the syringe in position for free movement of the plunger with respect to the barrel. The threads are biased in the engaged position. Thus, when the trigger is released, the threads on the plunger return to their position of engagement with the threads on the barrel. In the locked position, the plunger may be screwed into or out of the barrel by rotating the plunger, enabling the operator of the syringe to maintain strict control over the amount of pressure in the syringe. The triggering device employs a plurality of ramp and channel configurations which are disposed at approximately the same angle as the threads on the plunger and barrel. Thus, upon actuation of the triggering device, no net force results on the plunger which would cause movement of the plunger with respect to the barrel.

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Salt Lake City, UT, United States of America

Fred P Lampropolous