Fail-safe thermostat

A fail-safe thermostat apparatus for controlling fluid flow through an engine cooling system in response to changes of an ambient temperature surrounding the apparatus, the apparatus comprising:

• a stationary valve member configured to be positioned between conduit components of the engine cooling system, the stationary valve member being formed to include a flange ring and a valve seat configured to define an opening into a conduit;
• a movable valve member for engaging the valve seat to block fluid flow into the conduit through the opening;
• an operating spring for biasing the movable valve member to a closed position against the valve seat of the stationary valve member;
• a thermally responsive actuator coupled to the stationary valve member and to the movable valve member to move the movable valve member to an open position away from the valve seat when the ambient temperature exceeds a first predetermined temperature to permit fluid flow into the conduit;
• a bimetallic frame member having at least two fingers configured to engage the flange ring of the stationary valve member to couple the frame member to the stationary valve member and having a base to compress and hold the operating spring in engagement with the movable valve member, the fingers of the frame member being configured to move radially inwardly and disengage from the flange ring of the stationary valve member when the ambient temperature exceeds a second predetermined temperature greater than the first predetermined temperature;
• and
• a fail-safe spring located on an opposite side of the movable valve member from the operating spring, the fail-safe spring applying a biasing force against the movable valve member away from the valve seat to move the movable valve member to the open position upon disengagement of the frame member from the stationary valve member, the movable valve member being configured to block inward movement of the fingers when the movable valve member is in the open position, thereby preventing disengagement of the frame member from the stationary valve member.

A fail-safe thermostat apparatus for controlling fluid flow through an engine cooling system in response to changes of an ambient temperature surrounding the apparatus, the apparatus comprising:

• a valve configured to be positioned between conduit components of the engine cooling system, the valve being movable from a closed position to block fluid flow into a conduit to a radiator to an open position to permit fluid flow into the conduit;
• means for actuating the valve to move the valve to the open position when the ambient temperature exceeds a first predetermined temperature, the actuating means moving the valve to the closed position when the ambient temperature drops below the first predetermined temperature;
• means for permanently moving the valve to the open position when the ambient temperature exceeds a second predetermined temperature greater than the first predetermined temperature and upon failure of the actuating means to open the valve;
• and
• means for preventing operation of the moving means when the actuating means is functioning properly to open and close the valve.

A thermostat apparatus for controlling fluid flow through an engine cooling system in response to changes of an ambient temperature surrounding the apparatus, the apparatus comprising:

• a stationary valve member formed to include a valve seat configured to define an opening into a conduit;
• a movable valve member for engaging the valve seat to block fluid flow into the conduit through the opening;
• an operating spring for biasing the movable valve member to a closed position against the valve seat;
• a thermally responsive actuator for moving the movable valve member to an open position away from the valve seat when the ambient temperature exceeds a first predetermined temperature to permit fluid flow through the conduit;
• and
• a bimetallic frame member for compressing the operating spring in engagement with the movable valve member, the frame member being configured to release the compression on the operating spring when the ambient temperature exceeds a second predetermined temperature greater than the first predetermined temperature to permit the movable valve member to move away from the valve seat.

A thermostat apparatus for controlling fluid flow through an engine cooling system in response to changes of an ambient temperature surrounding the apparatus, the apparatus comprising:

• a valve configured to be positioned between conduit components of the engine cooling system, the valve being movable from a closed position to block fluid flow into a conduit to a radiator to an open position to permit fluid flow into the conduit;
• means for actuating the valve to move the valve to the open position when the ambient temperature exceeds a first predetermined temperature, the actuating means moving the valve to the closed position when the ambient temperature drops below the first predetermined temperature;
• and
• a bimetallic frame member for supporting the actuating means, the frame member releasing the actuating means to cause the valve to move to the open position when the ambient temperature exceeds a second predetermined temperature greater than the first predetermined temperature and upon failure of the actuating means to open the valve.