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Retractable lancet

  • US 4,735,203 A
  • Filed: 12/12/1986
  • Issued: 04/05/1988
  • Est. Priority Date: 12/12/1986
  • Status: Expired due to Term
First Claim
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1. A retractable, non-reusable bleeding time lancet apparatus, comprising:

  • a housing having an end opening;

    blade means;

    carrier means for fixedly mounting said blade means and mounted in said housing for sliding motion toward and away from said end opening;

    resilient biasing means comprising one and only one torsion spring mounted in said housing in a prestressed condition and operatively coupled for selectively and in sequence, urging said carrier means in opposite directions for achieving said sliding motion in a compound motion comprising, in sequence, motion first toward and then away from said housing end opening as said resilient biasing means goes from said prestressed condition toward an unstressed condition;

    non-resettable release means for initially retaining said biasing means in said prestressed condition and selectively activatable once and only once for releasing said resilient biasing means to urge said carrier means in said compound for momentarily projecting and then rapidly retracting at least a cutting edge of said blade means through said end opening;

    cooperating means on said housing and said carrier means for defining respective limits of sliding motion of said carrier means corresponding to extended and retracted positions of said blade means cutting edge relative to said housing end opening; and

    means operatively engaging said resilient biasing means with said carrier means for achieving said compound motion of said carrier means;

    said release means being operatively disengaged from said biasing means upon release thereof and incapable of re-engagement therewith;

    said compound motion comprising an initial portion including extension of said carrier means for projecting said blade means cutting edge outwardly of said housing end opening, immediately followed by a second portion including retraction of said carrier means for retraction of said blade means cutting edge back into said housing and for thereafter positively holding said blade within said housing to prevent further projection of said cutting edge outwardly of said end opening; and

    wherein said torsion spring comprises a coiled spring having a helical body and at least one outwardly projecting free end portion, and wherein said free end portion urges said carrier means in said compound motion.

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