| 摘要 |
A wheel chair (A) has at least one wheel (50) rotatably mounted to a side frame (14). A combined wheel lock and hill holder assembly (D) is mounted adjacent an outermost peripheral surface of a tire (60) mounted to a rim (58) of the wheel. The wheel lock and hill holder assembly has a linkage including a handle member (74) and a brake lever (80) both pivotally connected to the base. A link (84) is pivotally connected in between. Shifting the handle member causes the brake lever to move an axle (90) toward and away from the peripheral surface of the tire. A cam surface (94) having a plurality of projections (102) is rotatably mounted on the axle. In a first mode (FIG. 3), the wheel is free rolling. In a second mode (FIG. 4), the cam surface is moved by the handle into firm friction engagement with the tire peripheral surface to lock the wheel against any rotation. In a third mode (FIG. 5), the cam surface is spring biased into engagement with the wheel such that rotation in one direction is permitted but rotation in the opposite direction causes increasing engagement between the cam and the tire peripheral surface locking the wheel against rotation in that direction.
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