To provide a backing brake mechanism of a safe wheelchair, a mechanism which automatically brakes to stop the backing movement of wheels simultaneously with standing-up of a user.SOLUTION: The seat frame 10 of a wheelchair W is structured with freely laterally movable left/right plates around a side edge shaft installed on the outside end, with the seat frame constituted in a rising state through an energization mechanism during the unseated time. In the seated time, it is constituted in a lowering state against the energization mechanism by a body weight load, with the seat frame connected freely interlocking manner with a bending connection rod 20R. The tip of the bending connection rod is connected with the base end of a brake shaft pivotally supported on the wheelchair frame in the middle part. The tip of the brake shaft is made a nearly U-shaped braking hook 41R which is freely pressed on/released from the wheel tire surface of the wheelchair. A distance from the middle part of the brake shaft 40R pivotally supported on the wheelchair frame to the braking hook of the brake shaft tip is formed shorter than a distance from the wheel shaft to the wheel tire surface. The pivotal support part of the brake shaft in the middle of the brake shaft is arranged forward from the wheel shaft.SELECTED DRAWING: Figure 1【課題】立ち上がりと同時に自動的に車輪の後退移動にブレーキがかかる安全な車椅子の後進ブレーキ機構を提供する。【解決手段】車椅子Ｗの座フレーム１０を外側端に設けた側縁軸を中心に左右回動自在の左右プレートで構成し、座フレームは非着座時には付勢機構を介して上昇状態に構成する。着座時には体重負荷により付勢機構に抗して降下状態に構成し、座フレームは折曲連結ロッド２０Ｒと連動自在に連結する。折曲連結ロッドの先端は中途部を車椅子フレームに枢支したブレーキシャフト基端と連結し、ブレーキシャフト先端は車椅子の車輪タイヤ表面に圧着離脱自在の略Ｕ字状のブレーキングフック４１Ｒとし、車椅子フレームに枢支したブレーキシャフト４０Ｒの中途部からブレーキシャフト先端のブレーキングフックまでの距離は車輪軸から車輪タイヤ表面までの距離より短く形成する。ブレーキシャフト中途のブレーキシャフト枢支部は車輪軸より前方に配設した。【選択図】図１
