Safety device for mobile work platform lift
AssigneeAmerican Mobile Corporation
InventorLeonard L. Lenz
Life of this patent
Estimating the term…
Abstract
A mobile work platform lift assembly is illustrated wherein a platform carriage is movable up and down by power operated cables on rails carried by a tower. The tower is movable from a horizontal to a vertical position. A safety mechanism is provided for locking the platform carriage with respect to the rails when the tower is in a vertical position if for any reason the cables no longer offer support for the carriage and when the tower is in a lowered horizontal position, the same mechanism fixes the platform carriage with respect to the rails to avoid longitudinal movement of the platform carriage with respect to the tower.
Claims3
In a mobile work platform lift assembly wherein a wheeled vehicle carries a pivoted tower movable from a substantially lowered position to an upright substantially vertical position for carrying a work platform and having a platform carriage movable responsive to a supporting cable on parallel rails longitudinally mounted on said tower, the improvement including:
- A. means mounting the horizontal work platform on said platform carriage extending outwardly in cantilevered relation on said platform carriage;
- B. a first pair of transversely spaced wheels carried on an upper portion of said platform carriage engageable with the rails on a side thereof remote from the work platform;
- C. a second pair of transversely spaced wheels carried on a lower portion of said platform carriage engageable with the rails on the other side of the rails;
- D. a stop member opposite said first pair of wheels on said other side of the rails in spaced relation thereto;
- E. wedging means carried by said carriage opposite said stop member held out of engagement by said supporting cable when said platform carriage is supported thereby;
- F. an oscillatable shaft carried transversely of said platform carriage in horizontal alignment with a respective rail;
- G. linkage means normally held by cable tension so as to maintain said wedging means in deactivated position;
- H. resilient means normally urging said linkage means to move said wedging means into wedging engagement with said rail;
- I. an outwardly extending crank arm fixed adjacent one end to said shaft;
- J. a pair of arms extending across said platform carriage;
- K. means pivotally supporting each of said arms with respect to said platform carriage in an intermediate portion thereof;
- L. means connecting an adjacent end of each of said arms to a respective crank arm;
- M. means connecting the other end of each arm to an adjacent cable;
- O. a compression spring bearing against each arm intermediate said means pivotally supporting each of said arms and said means connecting the other end of each arm to an adjacent cable;
- and
- P. means limiting upper movement of said arms as a result of force exerted thereon by said cable;
- whereby when said cable is no longer supporting said platform carriage said wedging means engages said rails engaging said stop member.
Dependencies are inferred from the claim text.