Motors: expansible chamber type – Plural relatively movable or rigidly interconnected working... – Condition responsive means for modifying working member...
Patent
1984-09-10
1990-01-09
Garrett, Robert E.
Motors: expansible chamber type
Plural relatively movable or rigidly interconnected working...
Condition responsive means for modifying working member...
91518, 91520, 91420, 254 89H, B66F 346, B66F 704, B66F 720
Patent
active
048920282
ABSTRACT:
A fluid operated circuit for controlling the movement of pistons contained in the drive and idler cylinders of a conventional dual post vehicle lift assembly of the type wherein the cylinders are hydraulically connected in tandem so that movement of the idler cylinder piston is dependent upon movement of the drive cylinder piston and wherein the pistons, while operative to lift and lower movable article supporting structures, are not fixedly connected thereto. The circuit employs a pilot operated check valve responsively connected to the lower ends of the two cylinders for preventing the drive cylinder piston from descending when the article supporting structure associated with the idler cylinder is locked or jammed in an elevated postion, a first tow-position control valve for perventing the drive cylinder piston from descending when the article supporting structure associated with the drive cylinder is locked or jammed, a simple check valve connected in shunting relation across the first control valve for restoring the latter to an open state after it has closed, and a second two-position control valve which is manually operated as desired to drain hydraulic fluid from the drive cylinder to permit lowering of the pistons and their associated article supporting structures so long as both of the latter are free of restraint.
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ANSI Graphic Symbols: Fluid Power Diagrams, ANSI.
Hydraulic Handbook 2nd Ed., Trade & Technical Press Ltd.: Surrey, England 9/1960, p. 378.
Garrett Robert E.
Kapsalas George
Miller Jr. Maurice L.
VBM Corporation
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