An improvement is that the anesthesia needle guiding passage (3) is arranged in a guiding groove (4) on the outer wall of the tube wall.
一种改进是所述麻醉针引导通道(3)是设置于管壁的外壁上的引导槽(4)。
2
A needle valve with a threaded spindle is unscrewed to open a passage for the liquid to escape to the reservoir from the cylinder when the jack is required to be lowered.