Elevator – industrial lift truck – or stationary lift for vehicle – Having specific load support drive-means or its control – Includes fluid supporting ram in drive-means
Patent
1997-03-06
1999-01-05
Noland, Kenneth
Elevator, industrial lift truck, or stationary lift for vehicle
Having specific load support drive-means or its control
Includes fluid supporting ram in drive-means
91447, 13711507, B66B 904
Patent
active
RE0360228
ABSTRACT:
A hydraulic elevator up direction control system is provided that has a circulating valve connected between the supply and the return of a source that normally supplies pressure to the cylinder of an elevator. The circulating valve is controlled by a computer regulated stepless variable solenoid valve that influences the pilot fluid pressure in the operating chamber of the circulation valve to control the size of the opening of the circulating valve and thereby the volume of fluid passing through the circulating valve. This affects inversely the volume of fluid passing through a fluid flow measuring valve, to the cylinder, to provide selectably variable up speeds of travel facilitating a fast, smooth, accurate ride of the elevator car as it approaches a stopping point relative to an upper floor of a building. Such operation is substantially independent of the system pressure and fluid viscosity. A selectably variable speed down direction control system operates on largely the same principle.
REFERENCES:
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patent: 5014823 (1991-05-01), Pelto-Huikko
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patent: 5156088 (1992-10-01), Pelto-Huikko
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Flow Measurement & Meters, A. Linford, E.& F.N. Spon, Ltd., London, 1961, p. 261.
Chovanes Eugene
Noland Kenneth
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