| 摘要 |
A syringe of cartridge type with such a structure that a cartridge filled with liquid medicine is fitted in a holder having a needle cannula at the tip thereof and the cartridge is moved forward and pierced with said cannula so that the medicine can be injected into an object, in which an erroneous injection of excessive quantity of the medicine when the piston rod of the cartridge is pushed and pierced with the needle cannula is prevented. The syringe is provided with a releasable locking mechanism which advances the piston rod (15) and barrel (11) integrally with each other without the movement of the piston (14) in the barrel (11) of the cartridge (10) when the piston rod (15) is pushed forward. For instance, in the first embodiment, after the locking mechanism (21) is released by pressing an engaging piece (24) for close contact thereof with the piston rod (14) when the needle cannula (5) pierces the tip of the barrel (11), the piston (14) is driven forward in the barrel (11) when the piston rod (15) is pushed, whereby the medicine is injected through the needle cannula (5). <IMAGE> |
