Crown Equipment Corporation

James L Hoying

John R Harman

Randall D Plaugher

A lift truck provided with a fixed mast section, several moveable mast sections and a carriage supporting load carrying forks and operator's platform is hydraulically raised and lowered. Mast chains interconnect the fixed mast section and the moveable mast sections and the moveable mast sections and the carriage. One pair of cushioning devices is placed between the fixed mast section and lower most moveable mast section and a second pair of cushioning devices is placed between the uppermost moveable mast section and the carriage. Each cushioning device two spring elements, one with a relatively soft spring rate, the other with a relatively stiff spring rate. The cushioning devices and a common hydraulic connection between hydraulic cylinders combine to reduce the shock and jerk felt by the operator during mast staging while raising or lowering the mast in either an empty or loaded condition.

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Chickasaw, OH, United States of America

James L Hoying