Patent ID: 8317812

Claim:
A lancet device comprising, in combination: a. a hollow housing with a longitudinal axis and a proximal end and distal end, the hollow housing having, a proximal end opening extending through the hollow housing to a housing interior, and at least one guide rail on an interior wall of the housing interior, extending in a direction between the proximal end and distal end, the guide rail having a free end; b. a slider retained by the hollow housing in sliding engagement with the hollow housing, the slider comprising, a trigger portion to protrude at least in part from the proximal end, at least one drive portion extending into the housing interior, that includes a driving surface; c. a needle holder that carries a lance, the needle holder in sliding and rotational engagement within the housing interior, the needle holder defining a drivable surface that can engage the driving surface of the slider, the lance carried by the needle holder in an orientation with a puncturing end of the lance directed toward the proximal end; and d. a biasing means to urge the needle holder toward the proximal end and against the slider, wherein at least one of the driving and drivable surfaces is angled to bias the needle holder against the guide rail during displacement of the needle holder towards the distal end, and to send the drivable surface over the free end once the drivable surface is driven towards the distal end until the drivable surface is able to rotate about the longitudinal axis, and then to pass over the free end and be fired by the biasing means with sufficient momentum toward the proximal end to extend the puncturing end through the proximal end opening with sufficient force to pierce tissue brought into contact therewith, and then to be retracted by the biasing means sufficient to hold the puncturing end not beyond the proximal end opening; wherein a guide body is provided to locate with the distal end opening of the hollow housing to enable assembly in the correct pre-firing rotational orientation of the slider and needle holder within the hollow housing, the guide body being removable after assembly of the slider and needle holder with the hollow housing; wherein a guide aperture is provided in the guide body complimentary to the axial cross sectional shape of the slider and the needle holder and opening into the hollow housing when assembled therewith, and wherein the guide body comprises, at least one locating portion to engage with the hollow housing, wherein the at least one locating portion aligns the guide aperture on the hollow housing to allow assembly there-through of the slider and the needle holder into the correct pre-firing orientation against the guide rail of the hollow housing.