Abstract: A carriage (11) has a carriage body (12) to extend across the top face of a track. A fixed bearing arrangement (14) includes a bearing (15a, 15b) to engage a first side of the track and having a rotational axis located in a fixed position on the carriage body. A self-adjusting bearing arrangement (19) includes a movable bearing (20) to engage a second side of the track and mounted on a pivot arm (21) having a pivotal connection (24, 25) with the carriage body. A bias spring is arranged to act on the pivot arm such as to maintain contact between the movable bearing and the second side of the track. The movable bearing (20) is not driven. The movable bearing (20) and the pivotal connection (24, 25) of the pivot arm (21) are both located at a first end of the pivot arm. The bias spring is spaced from the pivotal connection (24, 25) in a first direction.

Abstract: A track system includes a track 1 and one or more carriages 10 having bearing wheels engaged with the track such that the carriages can travel along the track. Each carriage has a single bearing 12 engaged with the inner side of the track and a pair of bearing wheels 13, 14 engaged with an opposite side of the track. The width of the track between the two sides varies such as to maintain a tolerance better than 0.05 mm between the bearing wheels and the respective sides of the track. The load capacity of the carriage can be increased and centred by making the single bearing 12 larger than the other two bearing wheels 13 and 14. The track 1 may be machined in one piece, optionally with an integral base plate. In another embodiment the track has spaced inner and outer sections with a rack engaged by a drive pinion mounted on the carriage between the two sections.