초록 ▼

An hydraulic elevator control system is provided including a by-pass valve connected between the supply and return of a source that normally supplies pressure fluid to the cylinder of the elevator and a setting valve that is operable by fluid supplied from the operating chamber of the by-pass valve

An hydraulic elevator control system is provided including a by-pass valve connected between the supply and return of a source that normally supplies pressure fluid to the cylinder of the elevator and a setting valve that is operable by fluid supplied from the operating chamber of the by-pass valve to control the operation of the check valve, thereby to achieve a creeping speed of travel of the elevator car as it approaches a stopping point relative to the floor of a building to compensate for variation in oil temperature and/or pressure that occur through increased loading of the elevator, there is mixed with the primary flow of fluid to the setting valve a secondary flow of pressure－and viscosity－responsive fluid that flows over a long-edged restrictor device.

대표청구항 ▼

In an hydraulic elevator control system including a pressure fluid source (10) having a supply and a return, means including a check valve (2) connecting the supply of said source with a cylinder 17 of the elevator, and means including a by-pass valve (3) connected across said source for by-passing

In an hydraulic elevator control system including a pressure fluid source (10) having a supply and a return, means including a check valve (2) connecting the supply of said source with a cylinder 17 of the elevator, and means including a by-pass valve (3) connected across said source for by-passing said check valve, said by-pass valve normally being biased by biasing means (33) to the open condition and including a by-pass chamber (18) for receiving pressure fluid from said source via a fluid restrictor (35) for displacing said by-pass valve to the closed condition against the force of said biasing means, and means including a solenoid valve (29) operable to connect said chamber with the return of said source and setting valve means (4) for controlling the operation of said check valve means as a function of the pressure of fluid in said by-pass chamber; the improvement which includes means (44,170) for mixing with the fluid supplied from said by-pass chamber to said setting valve a secondary volume of fluid that flows over pressure and viscosity sensitive long-edged restrictor means (170).