Coupling links coupled at one end to terminal ends of the working belt and rotatably coupled at the other end to the conveyance body, the coupling links being configured to rotate when the seat cushion body rotates with a front end portion thereof acting as a pivot and both end portions of the working belt move in an up-and-down direction, and a working link mechanism provided in a manner to operate in interlock with the rotation the coupling link, the working link mechanism being configured to shift a brake member in accordance with a direction of rotation of the coupling link into a state that the brake member is separated from a rear wheel to release braking, or into such a state that the brake member is brought into contact with the rear wheel to apply braking.本發明包含有:座位緩衝體,係於座部載置成可將前端部作為支點而旋動者;作動帶,係中途部配置於座位緩衝體之下表面側者;導引滾輪,係將作動帶之兩端部導向車體之兩側之下方者;彈簧,係朝下方彈性地拉伸作動帶之兩端部者;連結連桿,係一端與作動帶之末端連結,另一端與車體連結成可旋動,又,當座位緩衝體將前端部作為支點而旋動,且作動帶之兩端部朝上下方向移動時會旋動者;及作動連桿機構,係設置成與連結連桿之旋動連動而作動,並依照連結連桿之旋動方向,使煞車構件變位成離開後輪而解除煞車之狀態,或使煞車構件壓接於後輪而啟動煞車之狀態者。5‧‧‧座部6‧‧‧肘靠部8‧‧‧後輪15‧‧‧座位緩衝體25‧‧‧作動帶25a‧‧‧導出部分26‧‧‧導引體27,41,46‧‧‧支軸28‧‧‧擺動構件33‧‧‧連結件34‧‧‧彈簧36‧‧‧連結連桿36a‧‧‧第1連桿片36b‧‧‧第2連桿片37‧‧‧短管38‧‧‧作動桿39‧‧‧板料42‧‧‧第1作動連桿43‧‧‧第2作動連桿44‧‧‧煞車構件45‧‧‧作動連桿機構47‧‧‧卡止銷48‧‧‧凹部D,L,R‧‧‧箭頭記號方向
