Three stage mast

Details Three stage mast Three stage mast

2007-08-01

2010-11-02

Langdon, Evan H (Department: 3654)

Elevator, industrial lift truck, or stationary lift for vehicle

Industrial lift truck or required component thereof

Having extensible vertical guide for load support

C187S227000, C187S229000, C187S234000

Reexamination Certificate

active

07823698

ABSTRACT:
The present invention is directed to an apparatus and method for raising and lowering a three-stage forklift mast assembly having a reduced overall lowered height. A first linkage system on the outer and middle masts creates a 2:1 movement ratio of the middle mast with respect to movement of a piston arm in the first linkage system. A second linkage system on the middle and inner masts creates a 2:1 movement ratio of the inner mast with respect to the movement of the middle mast and an overall 4:1 movement ratio with respect to the movement of the piston arm in the first linkage system. A third linkage system on the inner mast creates a 2:1 movement ratio of a set of forks on the inner mast with respect to the movement of a piston arm in the third linkage system, allowing free lift of the forks.

REFERENCES:
patent: 1977815 (1934-10-01), Abbe
patent: 2883003 (1959-04-01), Arnot
patent: 3172500 (1965-03-01), Dolphin et al.
patent: 3589541 (1971-06-01), Melin
patent: 3774726 (1973-11-01), Bredberg
patent: 3774727 (1973-11-01), Berkestad
patent: 3786902 (1974-01-01), Ramsey
patent: 3841442 (1974-10-01), Erickson et al.
patent: 3968859 (1976-07-01), Ehrhardt
patent: 4015686 (1977-04-01), Bushnell, Jr.
patent: 4059172 (1977-11-01), Stedman
patent: 4261438 (1981-04-01), Olson
patent: 4307792 (1981-12-01), Benson et al.
patent: 4421208 (1983-12-01), Robinson, Jr.
patent: 4467893 (1984-08-01), Hobson
patent: 4476960 (1984-10-01), Yarris
patent: 4600084 (1986-07-01), Ray
patent: 5326217 (1994-07-01), Simpson et al.
patent: 5328321 (1994-07-01), Moffett et al.
patent: 5374156 (1994-12-01), Simpson et al.
patent: 5549437 (1996-08-01), Kishi
patent: 5984050 (1999-11-01), Ronald
patent: 2005/0036864 (2005-02-01), O'Keeffe
patent: 2077224 (1981-12-01), None
patent: 50-130124 (1977-05-01), None

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