| 摘要 |
A metering unit for metering measured-off quantities of a liquid 3 comprises a cylindrical housing 1 for receiving a container 2 of the liquid 3 in question. The housing has, at the distal end, a liquid discharge needle 5. The metering unit further has a plunger shaft 8 for actuating a plunger 4 for expelling the liquid. The plunger shaft 8 comprises a body part 11 having axially running, substantially flat side faces 12, 13, whilst the housing has a passage part arranged for the reception of the body part 11, which passage part is delimited by a substantially flat side face 14, which is arranged to bear against one 13 of the parallel side faces 12, 13 of the body part. The passage part 19 is also delimited by a number of flexible pins 15,16, which, in the relaxed state, extend essentially perpendicularly in towards the flat side face 14 of the passage part from an opposite- situated side, the free end of each pin being located at a distance therefrom which is less than the thickness of the said body part 11. The plunger shaft 8 can in this case only be moved forward in the direction of the distal end of the housing. <IMAGE>
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