Elevator – industrial lift truck – or stationary lift for vehicle – Stationary lift for roadway vehicle or required component... – Having specific drive means for support
Patent
1988-10-31
1990-09-11
Look, Edward K.
Elevator, industrial lift truck, or stationary lift for vehicle
Stationary lift for roadway vehicle or required component...
Having specific drive means for support
91443, 91447, 414674, B66B 920
Patent
active
049554611
ABSTRACT:
A hydraulic lift valve system for fork lift trucks comprising a three way valve including a spool in a bore having a first neutral position, a second lift position and a third lower position. In the second lift position, the spool functions to apply fluid from a source to a cylinder for lifting the fork of the truck only after the pressure exceeds the load pressure and a predetermined value as established by a first poppet valve. Upon shifting to the third position the spool functions to permit exhaust of the fluid in the cylinder and therefore lowering the fork only after a predetermined pressure is established in a pilot valve which permits the first poppet valve to open, thereby insuring that the fork of the lift truck is not lowered unless there is a predetermined load on the fork. By this arrangement, the problem of uncontrolled descent of the fork upon engagement of the fork with an object is obviated.
REFERENCES:
patent: 1628390 (1927-05-01), Cochran
patent: 2874681 (1959-02-01), Vander Kaay
patent: 3151455 (1964-10-01), Tennis
patent: 3241462 (1966-03-01), Karazija
patent: 3382771 (1968-05-01), Nutter
patent: 3438308 (1966-09-01), Nutter
patent: 3630216 (1971-12-01), Kelly
patent: 3871266 (1975-03-01), Schwab et al.
patent: 3960286 (1976-06-01), Spooner et al.
patent: 3990583 (1976-11-01), Nishida et al.
patent: 4088151 (1978-05-01), Schurger
patent: 4392771 (1983-07-01), Smalley
patent: 4593791 (1986-06-01), Matthews
patent: 4762203 (1988-08-01), Ryan
patent: 4892028 (1990-01-01), Stivers
Look Edward K.
Ryznic John E.
Vickers Incorporated
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