| 摘要 |
A track slide (4) intended to be moved along a track, particularly a mast or boom, having a groove (5) with an enlarged inner portion (18) and a narrow slot (20) defined by two opposite walls (38, 39) of the track. The slide (4) comprises a central profiled member (16) having an enlarged inner portion (17) for being received in the enlarged inner portion (18) of the groove (5) and a shaft portion (19) for extending through the slot (20). Furthermore, the slide (4) comprises a roller member for coacting with the outer face of the opposite side walls (38, 39) on each side of the groove (5). The roller member is formed of a plurality of roller bodies (27) arranged to rotate freely in a circumferential continuous path (22) with an outwardly open, longitudinal slot (23) and a return passage (24) on each side of the central profiled member (16). The use of freely rotating roller bodies ensures a relatively small rolling resistance in all situations, even if the slide should tilt in relation to the track. Moreover, the plurality of roller bodies ensures that the load on the wall portions, on which the roller bodies roll, is within an acceptable level. |
