The mechanism is intended for maintaining constant speed of a machine tool table regardless of the load (cutting variables). Pump 1 delivers fluid through flow-control valve 6 and pipeline 7 to the power cylinder whose piston is linked to the table. The upper chamber in housing 2 of the relief valve is connected to pipeline 7, and the lower chamber to pump 1 through pipeline 5. Housing 2 contains diaphragm 3 subject to the constant pressure of spring 8. Provided in the lower chamber of housing 2 is an orifice into which needle valve member 4 enters. If the load on the piston of the power cylinder increases at a constant setting of flow-control valve 6, the pressure of the fluid in the system increases, as it does in the upper chamber of housing 2. This bends diaphragm 3 downwards moving needle member 4, attached to the diaphragm, into the discharge orifice, thereby increasing the amount of fluid delivered by the pump into pipeline 7. As a result, the speed of the piston and table is automatically equalized. Table speed is varied by flow-control valve 6. If valve 6 is closed to some extent, the pressure in the lower chamber of housing 2 increases, diaphragm 3 is bent upward, opening the discharge orifice. When flow-control valve 6 is opened, the discharge orifice is closed.
$4042$EHP,Va$