| 摘要 |
A rail trolley has two sets of rotatable, peripherally grooved rollers (20a, 20b), for running on opposite edges respectively of a fixed rail (12) disposed therebetween. One set of rollers (20b) is displaceable, against the bias of springs (28), in a direction away from the other set of rollers (20a), to enable the trolley to be applied to or removed from the rail (12). A cam lever, (32) which carries two friction brake shoes, is arranged on the trolley such that angular displacement of the cam lever (32) causes one of the friction shoes to engage the rail (12) and thereby lock the trolley to the rail (12). The trolley is able to function as a fall arrest device with the rail fixed at any attitude. <IMAGE> |
