US 4,359,137 AGranted

Safeload indicator for aerial lift platform apparatus

AssigneeJLG Industries, Inc.

InventorsErnest J. Merz, Charles W. Walters

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Abstract

A workman's lift platform apparatus has a vertically swingable and extensible boom with a workman's platform at the outer end. A color coding indicating the amount of boom extension is provided on the fly section of the boom, visible to the workman in the platform, and an indicator plate having corresponding color coding is provided adjacent the controls on the platform. The indicator plate in the form of a drum is driven proportionately to the angular movement of the boom by a pair of sheathed, push-pull cables, or by a sheathed torsion cable. In other embodiments, the indicator plate is tilted in proportion to the angular movement of the boom by a sheathed push-pull cable or by a parallel bar linkage. A cursor is provided adjacent the indicator plate, and is part of a gravity-operated pendulum.

Claims16

Dependent claims

In a workman's lift platform apparatus comprising a telescopic boom pivotally mounted for luffing movement about a horizontal axis and having base and fly sections, means for extending and retracting the telescopic boom, means for luffing the boom, a workman's platform adjacent the outer end of the boom, a horizontal pivotal connection between the platform and the boom parallel to said horizontal axis, means for maintaining the platform level during luffing movement of the boom, and control means on the workman's platform for controlling boom luffing and boom extension, the improvement comprising:

means on the fly section of the boom visible to a workman at said control means for visually indicating the amount of extension of the boom,
an indicator drum on said platform adjacent said control means having thereon visual indicating means corresponding to the indicating means on said boom fly section, means for supporting said indicator drum on a horizontal axis parallel to said first mentioned horizontal axis,
means for driving said drum proportionately to the angle of the boom to the horizontal comprising cable means connected at one end to said drum and at the other end to said boom, and
a cursor adjacent said indicator drum.

1 more element

means on the fly section of the boom visible to a workman at said control means for visually indicating the amount of extension of the boom,
an arcuate indicator plate on said platform adjacent said control means having thereon visual indicating means corresponding to the indicating means on said boom fly section,
a cursor,
means mounting said cursor adjacent said arcuate plate for rotational movement about the axis of said arcuate plate,
a pendulum weight on said cursor,
means for mounting said indicator plate on said platform for pivotal movement about a horizontal axis parallel to said first mentioned horizontal axis, and
means for maintaining said indicator plate in a predetermined orientation relative to said boom when said boom is luffed about said horizontal axis to different angular positions.

4 more elements

Dependencies are inferred from the claim text.