Patent ID: 8578707
Filing Date: 2013-11-12
Classification: F15B,F16K,Y10T

Abstract:
1. A protection valve for a hydraulic drive system, the protection valve comprising: a valve body having a first end and an opposite second end; an actuator shaft movably disposed within the valve body; a thermal actuator body attached to the valve body at the first end, the thermal actuator body having an inlet for receiving a hydraulic fluid from a hydraulic drive system and an outlet for returning the hydraulic fluid to the hydraulic drive system; a thermal actuator disposed within the thermal actuator body in fluid communication with the hydraulic fluid for moving the actuator shaft from an un-actuated position wherein the valve body is closed to the ambient atmosphere to an actuated position wherein the valve body is open to the ambient atmosphere; a valve seat body attached to the valve body at the second end opposite the first end; a spring disposed between the valve body and the valve seat body, the spring being retained on the actuator shaft between the valve seat body and the valve body and biasing the actuator shaft towards the un-actuated position; a valve poppet movably disposed within the valve seat body and attached to the actuator shaft for movement therewith against the bias of the spring; wherein the thermal actuator is configured to move the actuator shaft and the valve poppet relative to the valve body, the thermal actuator body and the valve seat body from the un-actuated position to the actuated position in response to a temperature of the hydraulic fluid exceeding a predetermined maximum temperature.