| 摘要 |
<p>The hypodermic syringe has a pressure mechanism between the top of the cylinder and the needle holder. A locking device is provided at the level of the latter. Pressure can be exerted by a spring, or by a rolling membrane filled with compressed gas, while the locking device can consist of a thrust ring, and a fixed tapering one in the cylinder wall. Alternatively there can be a tapering portion of the wall itself.</p> |
