Cascade Corporation

David W Petronek

Pat S McKernan

Gregory A Nagle

Andrea Dal Dosso

D Clark Jordan

Harry F Weinert

Glenn Steven Prentice

Dennis W Gaibler

Troy J Schweitzer

Patrick A Armony

Clark D Jordan

Hydraulic valve circuitry adapted for hydraulic connection to a lift truck having a mast and at least one lift cylinder for alternately raising and lowering the mast. The hydraulic assembly is also adapted for hydraulic connection to an attachment to the lift truck, the attachment having opposed clamps actuated by respective clamp cylinders. The hydraulic assembly preferably comprises a valve circuit capable of causing the at least one lift cylinder to be an accumulator.

Equalized hydraulic clamp force control

A side shift limiting attachment for a material handing vehicle alerts the vehicles operator and restricts side shifting, lifting, tilting and/or rotation of the attachment when the side shift displacement is approaching or has reached a limit for a lift height.

Side-shift limiter

Hydraulic valve circuitry adapted for automatic weight-responsive control of load-clamping members of a load-lifting system having a free lift mast. The load-lifting system generally includes one or more fluid power actuator for applying a gripping force to a load, at least one elongate, longitudinally-extensible fluid power lifting device having a free lift range of motion and at least one main lift range of motion, and manually operated load-clamping and load-lifting selector valves. The hydraulic valve circuitry provides, independently, weight-responsive control of the load-clamping members when lifting a load, full-time automatic weight-responsive force control of the load-clamping members without concurrent manual actuation of load-clamping or load-lifting selector valves, and equalization of sensed load weight so that the sensed load weight is substantially independent of the longitudinally-extensible position of the lifting device.

Different exemplary control systems for a hydraulically powered load-handling clamp, of the type usually mountable on industrial lift trucks or automatically guided vehicles, are disclosed. The disclosed systems variably limit a hydraulic force, by which load-clamping arms move a load substantially transversely, automatically depending on the weight of the load being moved, so as to avoid excessive transverse force applied to fragile loads.

Hydraulic clamping systems having load side-shifting variably responsive to load weight

A regenerative hydraulic circuit for a clamping attachment limits the clamping force applied to a clamped load.

Clamping attachment with regenerative hydraulic circuit

A fork positioner, usable alternatively either as an attachment to an existing load-lifting carriage with forks, or as part of the original equipment of a load-lifting carriage, has a pair of elongate hydraulic piston and cylinder assemblies mountable in an interconnected parallel relationship between an upper transverse fork-supporting member and a lower transverse member of the carriage. Each of a pair of fork-positioning guide members has a fork-engagement surface movable by a respective piston and cylinder assembly and connectable thereto so that the fork-engaging surfaces face substantially perpendicularly away from an imaginary plane containing the respective longitudinal axes of the piston and cylinder assemblies. An exemplary carriage mounting the fork positioner is also disclosed, together with a wireless hydraulic function control system for use with the fork positioner or other multi-function load handlers.

Lift truck load handler

Hydraulic valve circuits capable of variably limiting respective maximum hydraulic pressures at which an assembly of bidirectional hydraulic power devices can move respective clamping members, such as forks or clamp arms, selectively in a closing movement toward each other, in an opening movement away from each other, or in a side-shifting movement in unison with each other, so as to provide damage-control capabilities for the control of the clamping members. The circuits preferably include one or more pressure-regulating valves interconnected with the assembly of power devices, and capable of variably limiting a maximum side-shifting pressure, at which said assembly can cause said side-shifting movement, in response to a maximum pressure selection. The circuits preferably include at least one override assembly, capable of overriding the maximum pressure selection to thereby lower the maximum side-shifting pressure automatically irrespective of the maximum pressure selection.

Hydraulic valve circuit with damage-control override

A lift truck fork positioner for respective inner and outer pairs of load-handling forks includes power actuators for selectively extending and retracting the outer pair of forks and latch assemblies for selectively detachably connecting an inner fork fixedly to a respective adjacent outer fork in spaced relation thereto automatically in response to the extension of the outer forks beyond a predetermined inner range of extension. Each latch assembly, when connecting the inner fork to the outer fork, fixedly prevents any narrowing of the spacing between the interconnected inner and outer forks, as well as fixedly preventing any widening of such spacing.

Growing community of inventors

Boring, OR, United States of America

David W Petronek