Patents by Inventor Philip C. Sefton

Philip C. Sefton 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).

  • Security equipment including trigger circuit
    Patent number: 4310835
    Abstract: Security equipment comprises a plurality of normally-open or normally-closed switch contacts connected in a loop circuit to a central control circuit. Each pair of switch contacts has a respective resistor connected in parallel therewith and the control circuit is operable to detect changes in resistance due, for example, to an intruder operating one of the switches.
    Type: Grant
    Filed: February 11, 1980
    Date of Patent: January 12, 1982
    Assignee: Donald Arthur Arnold
    Inventor: Philip C. Sefton
  • Touch switches
    Patent number: 4125783
    Abstract: A touch switch having two electrodes, one of which is driven by a pulse signal having a fast leading edge, and the other of which is connected to a logic detector circuit which is selectively triggered by said leading edge. The detector circuit operates to compare the pulse signal passed via the electrodes with one passed directly from the drive pulse generator, and gives an output to a triac trigger circuit dependent upon the amplitude of the signal coupled from one electrode to the other.
    Type: Grant
    Filed: September 23, 1976
    Date of Patent: November 14, 1978
    Inventor: Philip C. Sefton