High temperature limit thermostat with manual lockout safety
AssigneeRobertshaw Controls Company
InventorsMark I. Berns, Tom Buckshaw
Life of this patent
Estimating the term…
Abstract
A manual reset high temperature limit thermostat is provided. The manual reset lockout feature is provided by a lock rod that is outwardly transitioned upon actuation of the thermostat when the sensed temperature reaches its high level limit. A manual reset reset slide then engages the lock rod to prevent automatic resetting of the thermostat once the sensed temperature decreases below the thermostat set point. Resetting of the thermostat once the temperature has decreased may be accomplished by sliding the switch to disengage the reset slide from the locking rod. The thermostat internal snap action mechanism then retracts the lock rod and resets the thermostat's electrical contacts.
Claims20
A high limit electric thermostat having a temperature sensing bulb coupled via a capillary tube to a diastat within the thermostat housing, the diastat deflecting in response to expansion and contraction of fluid within the temperature sensing bulb, the deflection of the diastat acting through a member activates a snap-action mechanism at a particular temperature to transition an actuating mechanism from a first position to a second position to actuate a switch therein, the thermostat comprising:
- a terminal block having a first channel defined therein;
- a lock rod affixed to the actuating mechanism and extending through the first channel in the terminal block;
- a back cover having a second channel defined therein, the second channel terminating in a spring tab;
- a reset slide slidably accommodated in the second channel, the reset slide having a locking sled extending therefrom;
- and
- a bias spring operably positioned between the spring tab and the reset slide to bias the reset slide toward the lock rod.
A high limit electric thermostat comprising:
- a thermostat housing;
- a diastat positioned within the thermostat housing;
- a temperature sensing bulb coupled via a capillary tube to the diastat;
- a switch mechanism operably coupled to the diastat;
- a lock rod affixed to the switch mechanism and extending through the thermostat housing;
- a reset slide operably engaging the lock rod to allow transition of the switching mechanism from a first state to a second state and to prevent transition of the switching mechanism from the second state to the first state.
A temperature regulation system, comprising:
- a primary temperature control thermostat having a first temperature sensing element positioned within an environment to be regulated;
- a high temperature limit thermostat having a second temperature sensing element positioned within an environment to be regulated;
- a heating control mechanism electrically coupled to the primary temperature control thermostat and to the high temperature limit thermostat such that the heating control mechanism shuts off when either of the primary temperature control thermostat and the high temperature limit thermostat commands the heating control mechanism to shut off;
- and
- wherein the high temperature limit thermostat includes a manual reset mechanism comprising a lock rod affixed to a switch mechanism of the high temperature limit thermostat and extending through housing thereof, and a reset slide operably engaging the lock rod to allow transition of the switching mechanism from a first state to a second state and to prevent transition of the switching mechanism from the second state to the first state.
Dependencies are inferred from the claim text.