Patents by Inventor Keith Howell

Keith Howell 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).

  • Patent number: 4650259
    Abstract: Method and apparatus for selectively tensioning an endless, inextensible elastomeric belt entrained about a cooperating drive structure and idler structure having respective axes of rotation. A roller frame joined to a vehicular main frame supports the idler structure and constrains movement thereof to a longitudinal recoil path. The drive and idler structures are biasingly separated by a compression spring which exerts biasing force thereon in opposite longitudinal directions through a drive strut and an idler strut, respectively. The idler strut is connected to the idler structure longitudinally in front of the idler's axis. The length of one of the struts is adjustable to provide the desired tension in the spring and, thus, the entraining belt.
    Type: Grant
    Filed: November 12, 1985
    Date of Patent: March 17, 1987
    Assignee: Caterpillar Inc.
    Inventors: Phillip W. Alexander, Michael S. Freberg, Keith A. Howell, James E. Johnston
  • Patent number: 4292612
    Abstract: The contacts of a conventional molded case residential circuit breaker are opened and closed in relay fashion by a remotely controllable operator module. The operator module, utilizing the compliance of the breaker operating mechanism in its ON condition, acts directly on the breaker movable contact arm to effect a separation of the movable contact from the stationary contact sufficient to switch rated current.
    Type: Grant
    Filed: November 14, 1979
    Date of Patent: September 29, 1981
    Assignee: General Electric Company
    Inventor: E. Keith Howell
  • Patent number: 4115829
    Abstract: A circuit breaker electronic trip unit is equipped with a plurality of current transformers for sensing overcurrent and ground fault conditions in a distribution circuit. A ground fault signal voltage is applied to a differential amplifier together with an adjusted voltage establishing a desired ground fault signal pick-up level. The differential amplifier controls a variable duty cycle switch to establish charging versus discharging rates for a timing capacitor in accordance with the ground fault signal amplitude. When the voltage across the capacitor exceeds a predetermined threshold, a thyristor is triggered to draw a safe level of energizing current through a trip coil. Secondary open circuited protection is provided for any of the current transformers disposed externally of the circuit breaker.
    Type: Grant
    Filed: May 6, 1977
    Date of Patent: September 19, 1978
    Assignee: General Electric Company
    Inventor: Edward Keith Howell
  • Patent number: 4001646
    Abstract: A GFCI utilizes a single transformer in responding to ground faults on either of the line and neutral conductors of a distribution circuit. The transformer, a differential current transformer, has a secondary winding which is periodically strobed during a first sampling interval for the presence of a fault signal indicative of a line-ground fault. During a second sampling interval, a negative resistance network sets up a ringing oscillation in the transformer secondary circuit. If the neutral conductor is grounded through a low impedance ground fault, the oscillation is damped, and circuit interruption is initiated. Absent a low impedance ground fault on the neutral conductor, the oscillation amplitude increases to exceed a predetermined threshold level during the second sampling interval, and circuit interruption is not initiated.
    Type: Grant
    Filed: June 16, 1975
    Date of Patent: January 4, 1977
    Assignee: General Electric Company
    Inventor: Edward Keith Howell
  • Patent number: 3973171
    Abstract: The secondary winding of the differential current transformer in a ground fault circuit interrupter is normally short circuited through an electronic switch. A relaxation oscillator, including a timing capacitor, acts to periodically open the switch and divert any secondary current through a burden resistor, developing thereacross a relatively high amplitude fault signal voltage indicative of a liine ground fault. The timing capacitor discharges through the primary winding of a second transformer coupled with the neutral conductor to develop, in the event of a desensitizing neutral ground fault, a fault signal voltage across the burden resistor.
    Type: Grant
    Filed: May 19, 1975
    Date of Patent: August 3, 1976
    Assignee: General Electric Company
    Inventor: Edward Keith Howell
  • Patent number: 3963959
    Abstract: The secondary winding of a differential current transformer in a ground fault circuit interrupter is short circuited through an electronic switch. The switch is periodically opened to force any secondary current occasioned by the existence of a ground fault to flow through a burden resistor, thereby developing a relatively high amplitude signal voltage thereacross for processing by a signal processor pursuant to initiating circuit interruption.
    Type: Grant
    Filed: April 28, 1975
    Date of Patent: June 15, 1976
    Assignee: General Electric Company
    Inventor: Edward Keith Howell
  • Patent number: 3953766
    Abstract: An electronic module for ground fault circuit interrupters (GFCI) in both circuit breaker and receptacle configurations includes a signal processor having a plurality of fault signal threshold stages for differentially charging an integrating capacitor in accordance with the magnitude of the fault signal as amplified by a high gain differential amplifier. The accumulated charge on the integrating capacitor controls the generation of a trip signal. The processor also includes a highly stable grounded neutral excitation oscillator and a noise rejection network to combat nuisance tripping.
    Type: Grant
    Filed: September 16, 1974
    Date of Patent: April 27, 1976
    Assignee: General Electric Company
    Inventors: Edward Keith Howell, Donald Leland Watrous, Robert George Hodgins
  • Patent number: 3950677
    Abstract: An electronic module for use in ground fault circuit interrupting devices comprises an improved shell design structurally adapted for ease of assembly therein of the electronics and magnetics. The electronics, carried on a printed circuit board, is positionally mounted and retained in one shell compartment by integrally formed latching means. The magnetics are positionally mounted in other shell compartments and locked in place by the insertion therethrough of single-turn transformer winding elements. Potting of the electronics and magnetics thus becomes unnecessary.
    Type: Grant
    Filed: October 30, 1974
    Date of Patent: April 13, 1976
    Assignee: General Electric Company
    Inventors: Keith William Klein, Edward Keith Howell, Joseph Michael Palmieri