| 摘要 |
<p>The bed can be raised up to a required different horizontal level, and consists of a fixed base to which the legs are attached. It is joined to the mattress base or mobile frame on which the mattress base rests by at least two and pref. four links. The links are pivot mounted on axles fixed to the base. Each link is fixed to one of the ends of a spiral spring one end of which is fixed to an axle on the base, and the other end rests against the base. A catch fixed underneath the mattress base or its frame holds the links down against the base.</p> |
