Allis-chalmers Corporation

Dean A Matthews

Benonie C Ehrhardt

Walter A Pivarunas

The carriage lift and mast lift cylinders are sequentially extended and retracted in the reverse order of pressure required to actuate them by a sequencing valve to insure proper sequential movement of the lift carriage and extension of the mast sections.

Automatic sequencing circuit for lift cylinders

An improved structural arrangement for mechanically and hydraulically interconnecting a cluster of three hydraulic cylinders of the hydraulic jacks associated with the load carriage elevating and mast structure elevating functions of a forklift truck. The clustered cylinders include a centrally located 'secondary' cylinder and two oppositely disposed 'primary' cylinders symmetrically positioned contiguous to the centrally located secondary cylinder. Each cylinder has a corresponding attachment block rigidly secured thereto, each attachment block being provided with a hydraulic passage therethrough which communicates with an aligned hydraulic passage through the wall of its corresponding cylinder. An interconnecting block having an internal hydraulic manifold and outlet ports which are adapted to be aligned with the hydraulic passages of the respective attachment blocks and corresponding hydraulic passages through the walls of the respective cylinders, and thus to hydraulically communicate with the interior of the respective cylinders, is adapted to be bolted to the attachment blocks of the respective cylinders. An important feature of the construction is the 'shear ledge' construction for supporting the structural load on the interconnecting block to relieve the shear load on the bolts which secure the interconnecting block to the attachment blocks of the respective hydraulic cylinders. In accordance with this shear ledge construction the interconnecting block is provided with a welded plate defining an overhanging shoulder which seats on the upper surface of the attachment block of the centrally located secondary cylinder, and the attachment blocks of the oppositely disposed primary cylinders are recessed to define oppositely disposed shoulders which seat on the upper surface of the interconnecting block.

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Homewood, IL, United States of America

Dean A Matthews