The Raymond Corporation

Ralph E Allen

Christian D Gibson

Isaac Avitan

Stephen L Page

David L Kellogg

David J Radley

Donald G Peters

A travel speed limiting control system for lift trucks, particularly of the 'orderpicker' type, having an extendible mast, is disclosed. The truck travel speed which the operator can command is limited by factors including load weight, load elevation, heading angle and direction of truck travel (forward or reverse) . Optionally, other factors may be involved, such as lateral tilt and load moment. An algorithm including the desired input factors is continually processed by an on-board microcomputer to provide an instantaneous speed limit signal. In addition to its normal operating mode, the microcomputer is also arranged to operate in a 'learn' mode, whereby it runs through the ranges of various input signals and develops a set of stored values which indicate the allowable ranges of the inputs, as well as offset or bias values which compensate for manufacturing tolerances occurring in the components of the system.

Lift truck control systems

A lift truck mast arrangement minimizes stresses occurring in mast members using rearward chain anchor placement to apply a rearward counterbalancing moment to the mast so as to create a bending moment in portions of the mast below the instantaneous position of the load carriage which is substantially equal to the bending moment then occurring in portions of the mast above the load carriage.

Material handling apparatus

Use of a laterally-shiftable C-shaped frame which supports an auxiliary mast above its upper and lower extremities allows a lift truck to handle wider loads in a given aisle width, and decreases bending moments and inertial forces.

Elevations of a lift truck load carrier relative to shelves of a storage rack are accurately indicated by photosensor means on the load carrier operated by light reflected from reflectors on the storage rack. Raising and lowering the load carrier rotates the shaft of a retractable cable reel. Photosensor signals operate a clutch which connects the reel shaft to rotate a potentiometer over a limited range of heights surrounding the desired load carrier heights for each shelf in a vertical stack of shelves.

Lift truck having height indicating means

The fork carriage of a side-loader truck is journalled for rotation about a vertical axis between two arms, one above and one below the carriage, which transmit lateral load moments to a narrow vertical member. A vertically-extending torque shaft journalled on the vertical member carries gears on its opposite ends. The gears engage laterally-extending racks spaced widely vertically apart on a rearward carriage, so that lateral load moments apply minimum forces to the racks, and rotation of the torque shaft also serves to laterally position the vertical member and the fork carriage. The rearward carriage may comprise an elevatable, mast-guided laterally-fixed carriage, or an intermediate carriage may be interposed between the vertical member and the laterally-fixed carriage to provide greater lateral load extension. An intermediate carriage having a roller arrangement insuring adequate support at any lateral load position is shown. By mounting the truck load wheels on the ends of an axle member, a given truck design can be readily adapted for use in aisles by numerous different widths without changes in a heavy welded base frame of the truck.

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Greene, NY, United States of America

Ralph E Allen