Inventors:
Michael D'Alessio - Flushing NY
Charles Matcovich - Pearl River NY
Assignee:
Harsco Corporation - Camp Hill PA
International Classification:
B66B 1104
Abstract:
A drive pinion disengaging device for use in rack and pinion hoists includes an outer section of rack having toothed portions above and below, an at least potentially toothless portion, and a bridging rack section adapted to be removed at the toothless portion by the drive pinion when under a predetermined load to permit the latter to disengage the rack in case of malfunction. This permits the large rotational inertia to be dissipated without injury to the drive mechanism. The point of disengagement is such as to occur preferably only when the hoist is engaged by the safety landing buffers (since the drive pinion is normally the only effective support for the hoist). The bridging rack section may be in the form of a narrow sliding rack maintained in a longitudinal slot in the main rack (extending along the entire toothless portion and slightly up into the toothed portion above) and normally secured in place across such actually toothless portion by a shear pin, detent, and the like; or may be a rack having shearable teeth (preferrably thinner than the main rack, or optionally of a softer material).