A single-use lancet device is provided for drawing capillary blood
samples. The device includes a body having an upper portion and a lower
portion and a trigger carried by the upper portion of the body. The
trigger is movable between a first raised position wherein the device is
cocked and a second depressed position wherein the device is fired. A
needle assembly is provided which is movable between a cocked position
and a striking position. A free-floating drive spring is provided for
moving the needle assembly from its cocked position to its striking
position. A bounceback spring is integrally molded with the needle
assembly and includes a pair of generally V-shaped spring arms. A trigger
bar has a first position wherein it holds the needle assembly in its
cocked position, and the trigger bar has a second position wherein it
allows the needle assembly to move to its striking position as the drive
spring expands. The trigger carries a pair of guillotine-type blades
which sever the trigger bar and thereby releases the needle assembly from
its cocked position. Alternate trigger bars are provided which may be
deformed rather than severed. The device is also capable of assembly by
automatic equipment. The device is incapable of a second use because of
the deformation or severing of the trigger bar.