| 摘要 |
Attachments are described for enabling small front wheels of wheelchairs to negotiate side-walk curbs or the like. An arcuate rocker end for engaging the curb is fixed to a strut pivoted above the wheel and held in a ready position, determined by engaging abutments, by a prestressed, i.e. strained, spring which is further strained when the rocker end engages a curb and the advancing wheelchair causes the strut to swing backwards lifting the wheel onto the side-walk, whereupon, the rocker end is free to return to the ready position. The rocker end may be manually shifted to an idle position in which it is firmly held by the spring. In one example, one of the abutment members, which is normally fixed, is withdrawn to enable the strut to be forced behind it, the member then being released to retain the rocker end in the idle position. In another example, a mechanism is interposed between the strut and spring such that the spring can be further stressed as the mechanism passes over a dead-center position carrying the rocker end from the ready to the idle position or vice versa in each of which positions it is held by the stressed spring. In a third example the strut and spring form parts of a sub-assembly that can be rotated from the ready to the idle position of the rocker and latched in each position. |
