Retractable lancet

Abstract

A retractable, non-reusable bleeding time lancet apparatus comprises a housing having an end opening, a blade, and a carrier for fixedly mounting the blade and mounted in the housing for sliding motion toward and away from the end opening. A resilient biasing member is mounted in the housing in a prestressed condition and is operatively coupled for selectively urging the carrier for achieving sliding motion toward and away from the housing end opening. A non-resettable release member normally retains the biasing member in its prestressed condition and is selectively activatable for releasing the resilient biasing member to urge the carrier in a sliding motion for projecting at least a cutting edge of the blade through the end opening. Cooperating surfaces on the housing and carrier define respective limits of sliding motion of the carrier corresponding to extended and retracted positions of the blade cutting edge relative to the housing end opening. The resilient biasing member is operatively engaged with the carrier for achieving a compound sliding movement of the carrier comprising an initial portion including extension of the carrier for projecting the blade cutting edge outwardly of the housing end opening, immediately followed by a second portion including retraction of the carrier for retraction of the blade cutting edge back into the housing.