Abstract: An injection device has a needle (22) which, when the device is operated, is first caused to project, then liquid is forced out through it, and finally the needle is automatically retracted. The needle (22) extends forwardly from a capsule (18) that can slide longitudinally within a barrel-like body (1), a relatively weak spring (19) normally maintaining the capsule and needle retracted. A more powerful spring (14) acts oppositely on a plunger (26) which, when released, shoots the capsule forward by acting on the liquid therein, and then forces the liquid out through the projecting needle (22). At the end of the forward stroke the plunger (26) and capsule (18) are decoupled and the weak spring (14) returns the exhausted capsule and its needle to the retracted position.

Abstract: A disposable pricker has a two part body with the parts connected by a hinge (6). A spring (10) and a lancet (1) are entered in one tubular part (7) which is then hinged to a ready position in which the leading end of the lancet, projecting from the tube (7), is confined by guide (17,22) on the other part. The tip (4) of the lancet is protected by a cap (5) which is removed before or as the two parts (7,11) are hinged closely together. This takes the leading end of the lancet clear of the guide (17) and into a passage (13) with a restricted mouth (14). The spring (10), which may be energized at the ready position or by the guide (22) wedging the lancet (1) back, can then act to shoot the lancet (1) forward to cause momentary projection of the tip (4) through the mouth (14). Retraction is assured by the spring (10) or resilient tabs (21) at the mouth.

Abstract: A disposable pricker has a body (1,2) lance (4) spring (3) and cap (13) integrally moulded in plastics, the cap being subsequently separable. The lance tip (5) is a needle embedded in the moulding and relatively inaccessible within the body. Formations (17) within the cap compress the spring (3) as the cap is fitted until they are flexed aside by co-operation with abutments (7) within the body. The lance (4) is released and shoots forward for the tip (5) momentarily to project proud of the cap (13). The latter is made captive to the lance (4) during this movement and cannot be removed to repeat the operation. The lance tip (5) thus remains concealed within the cap (13). In another capless version, squeezing the body (31) wedges the lance (36) back until it escapes and is shot forward by a spring (38). On recovery within the body, the lance is blocked from reverting to the position where it can be re-actuated.