Importance

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Abstract

A hydraulic elevator up direction control system is provided including a circulating valve connected between the supply and the return of a source that normally supplies pressure to the cylinder of an elevator controlled by a two position switchable setting valve that influences the pilot fluid pressure in the operating chamber of the circulating valve to control the size of opening of the circulating valve and thereby the volume of fluid passing through the circulating valve affecting inversely the volume of fluid passing through a check valve, to provide two distinctive intermediate up speeds of travel in addition to the nominal full speed of travel facilitating a fast, smooth and accurate ride of the elevator car as it approaches a stopping point relative to an upper floor of a building. A three speed down direction control system presents no problems of significance and is not dealt with.

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First Claim