| 摘要 |
<p>The easy chair which converts into a bed incorporates five successively interhinging (A, B, C, D) metal frames in the conversion mechanism. the frames fold onto one another to form the chair seat, and two only operational movements are reuired to effect the conversion. With the frames retracted and folded three of the inter-frame hinges are in alignment. This arrangement produces frame stabilising moments which are in excess of those due to the folded mattress and tend to open the folded frame-work. After the primary operational movement the three frames (TE, QQ, Q1) remote from the chair back remain folded. At this stage two of the relevant inter-frame hinges are still in alignment counteracting the opening moments due to the residual folded mattress. The folding mechanism may include two pin-jointed lever arms (E.L. and LE) and a coil spring (M.L.).</p> |
