Patents by Inventor George L. Hetrick

George L. Hetrick has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Oven thermostat
    Patent number: 5025242
    Abstract: An oven control for self-cleaning ovens provides a hydraulic sensing system having a wafer-like bellows. The position of the bellows is adjusted by a face cam on a control shaft in the BAKE and BROIL modes of operation. The bellows also controls the temperature of the oven for SELF-CLEANING. However, the face cam does not determine the SELF-CLEANING temperature. A door lock operator switch is also operated by the bellows, but is connected so that the adjusted position of the bellows does not affect the door lock operating temperature. Three separate calibration adjustments are provided. The first calibrates the operating temperature in the BAKE and BROIL modes of operation. The second calibrates the SELF-CLEANING temperature, and the third calibrates the door lock operating temperature. A bimetal ambient temperature compensator is provided to compensate for variations in the ambient temperature of the control.
    Type: Grant
    Filed: July 24, 1990
    Date of Patent: June 18, 1991
    Assignee: Robertshaw Controls Company, Inc.
    Inventors: Calvin J. Holtkamp, George L. Hetrick, Richard Warren
  • Thermal cycling switch
    Patent number: 5021762
    Abstract: A thermal cycling switch has an insulated housing carrying a centrally located rotating cam. The cam operates a first ON/OFF switch connectable between a pair of contacts that are connected to one side of a load and one power line. The rotary cam also moves an adjusted contact mounted on an adjustable arm which cooperates with a cyling arm contact to operate as another switch between the other side of the load and another power line. The cycling arm includes a bimetal member which is electrically insulated at the base, as well as a current conducting strip formed of pure nickel metal extending along the low expansion side of the bimetal member.
    Type: Grant
    Filed: August 3, 1990
    Date of Patent: June 4, 1991
    Assignee: Robertshaw Controls Company, Inc.
    Inventor: George L. Hetrick
  • Temperature limiting wattage control for a ceramic cooking platform
    Patent number: 3946201
    Abstract: A sensor, located to respond to the temperature of the cooking platform and having a positive temperature coefficient of resistance throughout a range of temperatures up to the maximum selected safe operating temperature of the platform, is connected to a thermal cycling control switch and provides an increasing resistance with an increasing platform temperature to effect a wattage limiting control of the heating element supplying heat to the platform.
    Type: Grant
    Filed: February 27, 1975
    Date of Patent: March 23, 1976
    Assignee: White-Westinghouse Corporation
    Inventor: George L. Hetrick