Latch mechanism for preventing lancet oscillation in a lancing device

Abstract

A lancing device including a latch that pivots between a non-blocking position allowing a lancet carrier and a lancet to advance and retract through a first forward and reverse lancing stroke and a blocking position preventing further/excess/secondary oscillation of the lancet carrier and lancet. The pivotal latch can pivot about an axis perpendicular (e.g., for an L-shaped latch) or parallel/coaxial (e.g., for a sleeve latch) to the advancement and retraction motion of the lancet carrier and lancet.

What is claimed is: 
     
         1 . A lancing device, comprising:
 a housing;   a lancet carrier capable of receiving a lancet, the lancet carrier including a latch-engaging element and a pressed surface;   a drive mechanism operable to drive the lancet carrier through a lancing stroke, the lancing stroke including a forward position and a return portion;   a charging mechanism operable to charge the drive mechanism to a charged state, the charging mechanism including a latch-pivoting element; and   a latch mechanism comprising a latch member and a latch retainer, wherein the latch member is capable of pivoting between a blocking position and an intermediate non-blocking position, wherein the latch retainer is configured to releasably constrain the latch member to the blocking or intermediate non-blocking positions, and wherein the latch member includes a charge-pivot surface, a pressing surface, and a drive-stop surface.   
     
     
         2 . The lancing device of  claim 1 , wherein the latch-pivoting element is configured to engage the charge-pivot surface of the latch member to pivot the latch member from the blocking position to the intermediate non-blocking position. 
     
     
         3 . The lancing device of  claim 1 , wherein, as the lancet carrier travels along the forward portion the lancing stroke, the latch member pivots from the intermediate non-blocking position to a press non-blocking position. 
     
     
         4 . The lancing device of  claim 3 , wherein, in the press non-blocking position, the pressed surface of the lancet carrier interferes with the pressing surface of the latch member to prevent pivoting of the latch member to the blocking position 
     
     
         5 . The lancing device of  claim 4 , wherein, as the lancet carrier travels along the return portion of the lancing stroke, the pressed surface of the lancet carrier clears interference with the pressing surface of latch member and the latch member pivots to the blocking position whereby the drive-stop surface engages the latch-engaging element of the lancet carrier to prevent excess oscillation of the lancet-carrier. 
     
     
         6 . The lancing device of  claim 1 , wherein the lancet is integrated to the lancet carrier. 
     
     
         7 . The lancing device of  claim 1 , wherein the lancet is disposable. 
     
     
         8 . The lancing device of  claim 7 , further comprising an ejection mechanism operable to eject the disposable lancet from the lancet carrier. 
     
     
         9 . The lancing device of  claim 1 , further comprising a release mechanism for releasing the lancet carrier from the charged state and initiating the lancing stroke. 
     
     
         10 . The lancing device of  claim 1 , wherein the latch member comprises a body and a foot extending from the body, the foot defining the pressing surface and the drive-stop surface. 
     
     
         11 . The lancing device of  claim 1 , wherein the latch member is in the form of an L-shaped body. 
     
     
         12 . The lancing device of  claim 11 , wherein the charge-pivot surface is defined on the foot of the latch member. 
     
     
         13 . The lancing device of  claim 11 , wherein the latch member is biased to the intermediate non-blocking and blocking positions by a latch retainer. 
     
     
         14 . The lancing device of  claim 1 , wherein the latch member is in the form a sleeve body. 
     
     
         15 . The lancing device of  claim 14 , wherein the charge-pivot surface is defined on the body of the latch member. 
     
     
         16 . The lancing device of  claim 14 , wherein the latch member is releasably retained in the intermediate non-blocking position by a latch retainer. 
     
     
         17 . A method of lancing skin, comprising:
 charging a lancing device having a lancet for puncturing the skin during a lancing stroke, a lancet carrier holding the lancet and movable through the lancing stroke wherein the lancet carrier includes a latch-engaging face and a pressed face, and a latch mechanism with a pivotal latch member having a pressing face, a drive-stop face, and a charge-pivot face;   pivoting the latch member from a blocking position to an intermediate non-blocking position, wherein in the blocking position the drive-stop face of the latch member is positioned in a travel path of the latch-engaging face of the lancet carrier, and wherein in the intermediate non-blocking position the drive-stop face is removed from the travel path of the latch-engaging face;   retaining the latch member in the intermediate non-blocking position and the lancet carrier in a charged state;   releasing the lancet carrier from the charged state wherein as the lancet carrier travels along a forward portion of the lacing stroke the latch member is released and the latch member reverse-pivots from the intermediate non-blocking position to a press non-blocking position, wherein in the press non-blocking position the drive-stop face of the latch member is not positioned in the travel path of the latch-engaging face of the lancet carrier and the pressed face of the lancet carrier interferes with and is pressed against by the pressing face of the latch member; and   after the lancet carrier has reached an advanced position lancing the skin and then traveled along a return portion of the lancing stroke far enough that the pressed face of the lancet carrier has cleared interference with the pressing face of the latch member, reverse-pivoting the latch member from the press non-blocking position to the blocking position, wherein the drive-stop face of the latch member in the blocking position intercepts the latch-engaging face of the lancet carrier and prevents further lancet-carrier oscillations.   
     
     
         18 . The lancing method of  claim 17 , wherein the latch member includes a body and a protrusion extending therefrom, with the pressing face and the drive-stop face defined by the protrusion. 
     
     
         19 . The lancing method of  claim 17 , wherein the latch mechanism further includes a latch retainer that retains the latch member in the intermediate non-blocking position and upon release allows the latch member to reverse-pivot to the press non-blocking position, wherein the latch retainer is in the form of a resilient finger. 
     
     
         20 . A latch mechanism for preventing lancet oscillation in a lancing device, the latch mechanism comprising:
 a latch member including a charge-pivot surface, a pressing surface, and a drive-stop surface; and   a latch retainer,   wherein the latch member is capable of pivoting between a blocking position and an intermediate non-blocking position, wherein the latch retainer is configured to releasably constrain the latch member to the blocking or intermediate non-blocking positions, wherein the latch member is configured to pivot from the blocking position to the intermediate non-blocking position by engagement of a latch-pivoting element of a charging mechanism with the charge-pivot surface of the latch member, wherein the latch member is configured to pivot from the intermediate non-blocking position to a press non-blocking position as a lancet carrier translates along a forward portion of a lancing stroke and a pressed surface of the lancet carrier interferes with the pressing surface of the latch member, the interference preventing the latch member to pivot further, and wherein the pressed surface of the lancet carrier clears the interference with the pressing surface of the latch member as the lancet carrier travels along a return portion of the lancing stroke and the latch member pivots to the blocking position whereby the drive-stop surface of the latch member is positioned along a path of the lancet carrier to prevent excess lancet carrier oscillations.