| 摘要 |
A load-carrying dolly having four wheels (6, 7) adjacent the corners of i ts platform (1) is rendered immobile by conversion to a pallet-like conditio n by lowering bearers (9, 10, 11) into contact with the floor or ground (24) and then raising the platform (1) slightly to raise the wheels (6, 7) clear of the floor or ground by means of either of two pedals (25, 32), one below each end of the platform (1), with linkage (of either of two forms, not sho wn) to bars (23) connecting in ~slave~ pairs of toggle links (20, 21) by mea ns of which the bearers are suspended through beams (33) connecting upward e xtensions (12, 13, 14) at the ends of the bearers (9, 10, 11), the toggle li nks in each pair becoming locked by mating abutments (28) coming together wh en the links have passed slightly beyond in-line position, the mechanical ad vantage of the depressed pedal (25 or 32) being amplified by that of the pai rs of toggle links when passing through in-line positions.
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