Cascade Corporation

Harlan D Olson

Stanley E Farmer

An extensible-contractible four-stage telescopic mast for a lift truck having a single fluid-actuated ram of low-collapsed height for high visibility which accomplishes both free lift and mast extension. The associated chain reeving of the mast provides a lesser ratio of load carriage speed to ram extension speed during free lift than during mast extension. To obtain substantially uniform speed of the load carriage throughout its lifting range, the ram assembly has a variable speed of extension substantially inversely proportional to such ratio such that ram speed is higher during free lift than during mast extension. An arrangement of the four mast sections, associated chain reeving and hydraulic conduits is provided which is especially conducive to high visibility and maximum load capacity.

Lift truck mast having high visibility and extensibility

A hidden chain assembly adaptable for use in multi-stage telescopic masts for lift trucks. A lifting chain is positioned transversely between two juxtaposed elongate upright members within an elongate enclosure defined by transversely-extending longitudinal flanges of the upright members. The chain is connected to one of the upright members by an anchor located within the enclosure adjacent to one end of the upright member, and extends from the anchor through the enclosure longitudinally toward the opposite end of the upright member where it is trained about a sheave rotatably attached to the other upright member. The anchor includes a detachment structure which is operatively accessible while the anchor is within the enclosure for permitting detachment of the chain from the first upright member despite the hidden location of the anchor within the enclosure. This permits removal, for servicing or replacement, of the chain while the mast is in a fully-retracted position without requiring disassembly of the mast sections from each other. A detachable mast guide roller, and detachable interference stop for preventing hyperextension of the mast sections with respect to each other, are associated with the detachable chain anchor.

Hidden chain assembly for lift truck mast

A high visibility telescopic mast assembly for lift trucks having a pair of mutually reciprocable mast sections, a load carriage movably mounted thereon and a fluid actuated extensible-contractable fluid ram assembly for selectively lifting the load carriage and one of the mast sections with respect to the other mast section. The fluid ram assembly is mounted centrally between the uprights of the respective mast sections and is contractable to a height adjacent the longitudinal midpoint of the fully contracted mast so as to provide relatively unimpeded visibility over the top of the ram assembly between the uprights when the mast is contracted. The ram assembly is connected to the extensible mast section in such a way that the ram begins to lift the mast section at a speed identical to the speed of ram extension while the ram assembly is still substantially fully contracted. Two alternative embodiments of the invention are disclosed, one featuring no free-lift and one featuring partial free-lift of the load carriage.

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Sandy, OR, United States of America

Harlan D Olson