| 摘要 |
<p>A dental apparatus retracts supply hoses connected to associated dental instruments. A coil spring is used within a housing. The hose is interposed between the windings of the spring. When the hose is extended, the radius of the coil contracts causing control switches to be activated. A ratchet engages dogs on the spring preventing unwanted retraction. Upon release of the ratchet, the coil spring expands drawing the hose into the housing.</p> |
