| 摘要 |
An injection device is adapted to eject a sequence of doses from the needle (8) of a capsule (5) carried within its barrel-like body (1). A plunger (11) extending rearwardly from the capsule (5) has ratchet teeth (12) along its length engaged by pawls (21) at the forward end of a drive tube (23) biased forwardly by a spring (29) and manipulable by a knob (24) at the rear end of the body (1). The capsule (5) is in a sleeve-like carrier (4) having limited longitudinal travel, a lost motion connection (18, 19) to the drive tube (23) and an engagement with the ratchet teeth (12) by pawls (13). The drive tube (23) can be releasably retained in a rearward position by a trigger mechanism (26). When released, the drive tube (23) urges the plunger (11), capsule (5) and carrier (4) forwards to project the needle (8). The liquid charge acts effectively as a solid. With the carrier (4) stopped, the plunger (11) carries on to eject a dose, clicking past the carrier pawls (13). The re-prime, the knob (24) is pulled to retract the drive tube (23) and the carrier (4), the lost motion connection (18, 19) allowing the drive tube (23) to move further and have its pawls (21) click back along the plunger (11) until the trigger mechanism (26) re-engages. |
