US 3,995,761 AGranted

Anti-lowering device for a boom loader

AssigneeSperry Rand Corporation

InventorJoseph C. Hurlburt

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Abstract

In a loader having a boom structure that reciprocates along its sidewalls, at least one stop member, having a cam surface and an abutment surface, is disposed at a predetermined height adjacent one of the sidewalls and operative between first and second positions. In the first position, the stop member projects outwardly from the sidewall into the path of travel of the boom structure whereby a portion of the boom structure may be lowered into engagement with the abutment surface to prohibit further downward movement of the boom structure. As the boom structure is swung upwardly and engages the cam surface, the stop member retracts inwardly to the second position, thereby permitting the boom structure to be raised above the predetermined height. Preferably, a pair of stop members, each one disposed on opposite sidewalls of the loader, may be used.

Claims9

Dependent claims

An improved anti-lowering device for a boom loader having a frame including upwardly-extending laterally-spaced side members, a boom structure including a pair of arms and means for pivotally mounting said boom structure to the frame, and power means operably associated with said boom structure for raising and lowering in concert each of said arms along a path adjacent a corresponding side member, said anti-lowering device comprising:

a. a stop member including a cam surface and an abutment surface;
b. means for mounting the stop member at a predetermined height on one of the side members of the frame so that said abutment surface faces generally upwardly;
c. means for moving said stop member relative to said side member between a locking position and a retracted position;
d. means acting upon said moving means for biasing said stop member in the locking position with its abutment surface projecting outwardly from said side member into the path of travel of the corresponding arm so that said arm may be lowered into supporting engagement with said abutment surface to prohibit movement of said boom structure beyond a given height;
and
e. said biasing means yieldable to permit said stop member to be urged to said retracted position under conditions where said arm is raised upwardly into engagement with said cam surface.

3 more elements

An improved anti-lowering device for a boom loader mounted on a vehicle having an operator's station including an operator's seat, a frame including upwardly-extending laterally-spaced side members, a boom structure including a pair of arms and means for pivotally mounting said boom structure to the frame, and power means operably associated with said boom structure for raising and lowering in concert each of said arms along a path adjacent a corresponding side member, said anti-lowering device comprising:

a. a stop member;
b. means for mounting the stop member at a predetermined height adjacent one side member and spaced inwardly of the vertical plane of a respective arm, said stop member being movable between an outwardly extendible locking position and an inwardly retractable unlocking position;
c. means for biasing said stop member in a locking position wherein a portion of said stop member projects outwardly from said side member through the path of movement of a respective arm, the outwardly projecting portion comprising a cam surface and an abutment surface, the abutment surface engages the lower surface of said arm as said arm is lowered from a position above the predetermined height and thereby prohibits further downward movement of said arm;
d. said biasing means yieldable inwardly towards said frame to a retracted position as said arm is raised from a position below said predetermined height and engages said cam surface of the stop member;
and
e. means for retracting said stop member inwardly towards the frame and out of the path of movement of said arm to an unlocking position for unobstructed travel of said arm along a path adjacent said side member, said retracting means is interconnected to said seat member and operably associated therewith so that said stop member is retracted inwardly to the unlocking position as said seat member is moved downwardly with respect to said vehicle and as said seat member moves upwardly from its downward position, the stop member is extended outwardly to the locking position.

3 more elements

Dependencies are inferred from the claim text.