| 摘要 |
A folding backrest of a wheelchair has two attendant handles fixed to upper tubes hinged to vertical lower tubes so as to be turnable into lowered positions. Supported on the upper tubes are respective cams turnable rearwardly by an attendant about a horizontal axis and in opposition to springs, from positions in which they bear against horizontal pins fixed at the rears of the lower tubes and maintain the upper tubes in their raised positions, into positions which allow them to be lowered past the pins to permit the backrest to be lowered. |
