| 摘要 |
Apparatus for force restoration of a bearing retainer uses a loop of resilient line around a pulley at an end of the bearing retainer. One end of the loop attached to a slide and the other end is attached to a base of a positioning table. A second loop is similarly attached at the opposite end of the retainer. These loops apply equal tension to both ends of the bearing retainer as long as the bearing retainer remains in its proper position without creep. When the bearing retainer moves out of position, unequal forces are exerted by the two loops, with a resultant force in a direction necessary to return the bearing retainer to its proper position. This controls the position of the bearing retainer relative to the slide. Provision for detecting and controlling broken force restoration lines may be included. In a second embodiment, a positioning table is disposed in a non-level position wherein gravity tends to produce bearing creep in a downward direction. A loop applying force in the upward direction overcomes the tendency for downward creep. In a further embodiment, a pinion engages racks on the base and the slide. The axis of the pinion is resiliently connected to the retainer to tend to urge the retainer in a direction opposite to a resulting creep.
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