| 摘要 |
The preferred embodiment is a platen drive unit that propels the platens of vehicles moving along a track. The platen drive unit may be readily used at any portion of the track, since it acts as a castor about a kingpin assembly, thereby substantially reducing the effects of roller scrub in curved track portions. A self energizing structure balances a dual-pivot arrangement of frames, such that the drive roller of the unit is balanced to intersect the conveyance plane without imposing a "bump" or lurch upon a vehicle that first engages the drive roller. Additionally, the drive roller is preferably a dual-rate tire which features a compliant range, within which the tire is readily deformed, but which continues to drive the platen with a large normal force. Beyond the compliant range, the tire is not compliant to deformation. The dual-rate tire may be created by constricting the circumference and filling the deformed tire with a urethane filler, which is allowed to cure. The constricting influence is removed, and the tire tread punctured to allow air to fill an ullage between the filler and the tread, creating the compliant region.
|
