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Blood sampling device

  • US 5,873,887 A
  • Filed: 10/25/1996
  • Issued: 02/23/1999
  • Est. Priority Date: 10/25/1996
  • Status: Expired due to Term
First Claim
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1. A blood sampling device, comprising:

  • a housing (12, 14, 18,

         20);

    a shaft (50) disposed in said housing (12, 14, 18,

         20);

    a lancet (40) operatively coupled to said shaft (50), said lancet (40) being movable between a retracted position in which said lancet (40) is disposed within said housing (12, 14, 18,

         20) and an extended position in which said lancet (40) extends outside of said housing (12, 14, 18,

         20);

    means (50, 52, 60,

         64) for retaining said lancet (40) in said retracted position;

    means (51) for causing said lancet (40) to automatically move from said retracted position to said extended position; and

    means for generating a reduced internal pressure within an area in said housing (12, 14, 18,

         20) as said lancet (40) moves from said retracted position to said extended position to facilitate drawing blood from a skin puncture to be made by said lancet (40) into an interior portion of said housing (12, 14, 18,

         20), said internal pressure being less than an ambient pressure outside of said housing (12, 14, 18,

         20), said means for generating a reduced internal pressure comprising;

    a suction chamber (88) disposed in said housing (12, 14, 18,

         20), said suction chamber (88) having a diameter and a substantially air-tight end;

    an acceleration chamber (92) disposed in said housing (12, 14, 18,

         20) and being disposed generally coaxially with said suction chamber (88), said acceleration chamber (92) having a diameter larger than said diameter of said suction chamber (88); and

    a plunger (46) connected to said shaft (50), said plunger (46) having an exterior portion (94) which makes sealing contact with said suction chamber (88) so that said reduced internal pressure is formed within said suction chamber (88) when said plunger (46) is moved in a direction away from said substantially air-tight end of said suction chamber (88), said exterior portion (94) of said plunger (46) having a diameter smaller than said diameter of said acceleration chamber (92) to facilitate acceleration of said shaft (50) towards said extended position.

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