The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 31, 1993
Filed:
Jun. 04, 1990
Michael H Schrick, Lexington, KY (US);
Donald E Moore, Lexington, KY (US);
Link-Belt Construction Equip. Co., Lexington, KY (US);
Abstract
A traveling crane incorporates a self-retracting/erecting live mast or the like, pivotally mounted on the base unit and capable of moving to and from a flipped, stowed position on the opposite side of vertical from the positions of the normal operating mode. A cable and winch is provided to raise and lower the mast during the normal operating mode and to move the mast toward the stowed position. A power cylinder operates to control the mast during retraction and to erect the mast from the stowed position. A control system operates the power cylinder to controllably move the mast during retraction/erection. Flexible pendants and telescopic guide links interconnect the cylinder with the mast and the base unit. Optimum operating angles are provided. The control system includes an electrical circuit and a hydraulic circuit, the hydraulic circuit having a restricted orifice to resist movement of the mast by gravity during retraction. The electrical circuit includes interlocks to disable the cable and winch at a selected angle and to place the cylinder in a free float mode during normal crane operation. The method includes the steps of pivotally moving the mast with the cable and winch, engaging the mast by the power cylinder during retraction/erection and counterbalance controlling the mast movement.