Patents by Inventor John P. Hoffman

John P. Hoffman 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: 5949330
    Abstract: Systems for monitoring sensed parameters and diagnosing fault conditions are useful in connection with many machines. Advantageously, such systems are capable of indicating the level of the sensed parameters in both a graphical and a digital format. In the subject invention, a switch selects one of a normal mode and a numeric readout mode. A sensor produces a sensor signal. A device displays a number in digital form that is representative of the sensor signal in response to the switch selecting the numeric readout mode. A gauge is provided to display the sensor signal in graphical form in response to the switch selecting the normal mode and to flash an illuminable device in response to the switch selecting the numeric readout mode.
    Type: Grant
    Filed: November 12, 1993
    Date of Patent: September 7, 1999
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney
  • Patent number: 5646373
    Abstract: An apparatus for improving the power dissipation of a semiconductor device surface mounted on a printed circuit board having at least a top printed circuit board layer and a bottom printed circuit board layer is provided. The apparatus includes a first pad of metallic material connected to a top surface of the top printed circuit board layer. The semiconductor device is connected to the first pad. A second pad of metallic material is connected a to the top surface of at least one of the top and bottom printed circuit board layers, wherein the second pad is electrically isolated from the semiconductor device. The apparatus also includes at least one thermal via for heat transfer through the printed circuit board layers thermally coupled to the thermal pad. A heat sink is thermally coupled to the at least one thermal via.
    Type: Grant
    Filed: October 5, 1995
    Date of Patent: July 8, 1997
    Assignee: Caterpillar Inc.
    Inventors: Larry C. Collins, James G. Cook, John P. Hoffman
  • Patent number: 5546264
    Abstract: An apparatus for providing reverse protection to an electronic circuit is provided. The electronic circuit has a positive input terminal and a negative input terminal. The positive input terminal is coupled to a positive battery terminal via the apparatus. The negative input terminal is connected to a negative battery terminal. The apparatus includes a MOSFET transistor having a gate terminal, a drain terminal and a source terminal. One of the drain terminal and the source terminal is connected to the positive battery terminal and an other of the drain terminal and the source terminal is connected to the positive input terminal. One end of a resistor is connected to the gate terminal. One end of a pair of Zener diodes is connected to the gate terminal. The other end is connected to the source terminal.
    Type: Grant
    Filed: December 22, 1994
    Date of Patent: August 13, 1996
    Assignee: Caterpillar Inc.
    Inventors: Gregory L. Williamson, John P. Hoffman
  • Patent number: 5541806
    Abstract: A driver circuit for controllably connecting an inductive load to a source of electrical power in response to an input control signal is provided. The inductive load includes an inductive winding of a solenoid. The driver circuit controllably connects and disconnects the inductive load to and from the source in response to a first control signal and controllably provides a discharge path for a flyback current of the inductive load in response to a second control signal. The driver circuit senses both the energizing current and the flyback current and responsively provides an energization path and a flyback discharge path in a non-overlapping manner.
    Type: Grant
    Filed: August 1, 1994
    Date of Patent: July 30, 1996
    Assignee: Caterpillar Inc.
    Inventor: John P. Hoffman
  • Patent number: 5457435
    Abstract: The present invention an apparatus provides a pulse width modulated signal to a load in response to an input signal. The apparatus receives the input signal and a feedback signal, determines a difference between the received signals, integrates the difference, and responsively produces an error signal. The error signal is compared with a reference wave signal and a correction signal is produced. The apparatus produces the pulse width modulation signal by conditioning the correction signal. The apparatus determines the feedback signal by attenuating the pulse width modulation signal in a manner similar to the attenuation caused by the load.
    Type: Grant
    Filed: March 25, 1994
    Date of Patent: October 10, 1995
    Assignee: Caterpillar Inc.
    Inventor: John P. Hoffman
  • Patent number: 5453939
    Abstract: Systems for monitoring sensed parameters and diagnosing fault conditions are useful in many applications. Advantageously, such systems are capable of operating in a plurality of operating modes and in connection with each of a plurality of machines. In the subject invention, a plurality of gauges are included for indicating the levels of the sensed parameters. A plurality of symbols are included for identifying sensed parameters. A control receives an identification code and selectively illuminates one or more of a plurality of gauges and symbols in response to the identification code. A plurality of warning lights are each associated with a switch-type input. A display selectively indicates a pin code for each switch-type input having a fault condition. The indicator lights having an associated switch-type input in the fault condition are flashed. A device selectively indicates a pin code in response to each diagnosable input having a present or a previous fault condition.
    Type: Grant
    Filed: September 16, 1992
    Date of Patent: September 26, 1995
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney, Joseph G. Kozlevcar
  • Patent number: 5401004
    Abstract: A method and apparatus for inserting a nozzle into the discharge bore of a steelmaking vessel including a carriage and a clamp means for demountably attaching the nozzle to the carriage. The apparatus further includes means to move the carriage toward or away from the steelmaking vessel while at the same time rotating the nozzle about its longitudinal axis as it is pressed into the discharge bore.
    Type: Grant
    Filed: May 3, 1994
    Date of Patent: March 28, 1995
    Assignee: Bethlehem Steel Corporation
    Inventors: Alvin M. Nestler, John P. Hoffman, John L. Hogan, Edward T. Witek
  • Patent number: 5374917
    Abstract: Instruments are often designed to operate in connection with a variety of machine types. Advantageously, such gauges are sufficiently flexible to indicate the levels of parameters in either a high warning or a low warning format. In the subject invention, a gauge includes a plurality of indicating segments being selectively illuminable for indicating the levels of the sensed parameter in the normal operating range, a high warning segment being selectively illuminable for indicating the level of the sensed parameter being above the normal operating range, and a low warning segment being selectively illuminable for indicating the level of the sensed parameter being below the normal operating range. An identification code is produced and received by an instrument which responsively enables one of the high and low warning segments.
    Type: Grant
    Filed: November 12, 1993
    Date of Patent: December 20, 1994
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney, Joseph G. Kozlevcar
  • Patent number: 5371487
    Abstract: Systems for diagnosing fault conditions in a plurality of inputs are useful in many applications. Advantageously, such systems allow troubleshooting by a single technician. The subject invention includes a plurality of sensors for producing sensor signals, each of the sensor signals indicating one of plurality of states of a parameter. A device is included to indicate that one or more of the sensor signals has changed states.
    Type: Grant
    Filed: November 10, 1993
    Date of Patent: December 6, 1994
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney
  • Patent number: 5369392
    Abstract: Systems for diagnosing fault conditions in a plurality of inputs are useful in many applications. Advantageously, such systems allow a technician to quickly and clearly identify the fault condition. The subject invention includes a plurality of sensors to produce a plurality of sensor signals. Each of the sensor signals is in one of a normal state or a fault condition and has an associated pin number. A plurality of indicator lights are also each associated with one of the sensor signals. A display individually indicates each pin number associated with a sensor signal in the fault condition. Each of the indicator lights associated with one of the sensor signals in the fault condition is flashed. The indicator light associated with the sensor signal for which the associated pin number is indicated by the display is steadily illuminated.
    Type: Grant
    Filed: September 16, 1992
    Date of Patent: November 29, 1994
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance
  • Patent number: 5361059
    Abstract: Gauges for indicating the level of sensed parameters are often provided in connection with a variety of machines. Advantageously, such gauges are sufficiently flexible to indicate the level of a parameter having a warning level that is dependent upon the level of a second sensed parameter. In the subject invention, a gauge indicates the level of a primary sensed parameter having a normal operating range. A sensor produces a signal indicative of the level of a secondary sensed parameter and the levels of the primary sensed parameter associated with the normal operating range are modified in response to the level of the secondary sensed parameter.
    Type: Grant
    Filed: November 12, 1993
    Date of Patent: November 1, 1994
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney, Joseph G. Kozlevcar
  • Patent number: 5337470
    Abstract: A nozzle extraction tool for removing a worn nozzle insert from a steelmaking vessel. The nozzle extraction tool including a support frame, a gripper assembly, and a drive piston for applying a force to the gripper assembly. The gripper assembly includes pivotal gripper arms and a rod assembly for pivoting and rotating the gripper assembly 360.degree. about the longitudinal axis of the worn nozzle insert. The rod assembly enables the gripper arms to be securely seated against the uneven surfaces of the worn discharge bore extending through the nozzle insert.
    Type: Grant
    Filed: April 26, 1993
    Date of Patent: August 16, 1994
    Assignee: Bethlehem Steel Corporation
    Inventors: John P. Hoffman, Alvin M. Nestler, Edward T. Witek, Donald J. Idstein
  • Patent number: 5335896
    Abstract: A two piece nozzle insert for use in a steelmaking ladle comprising a nozzle segment and a lock ring segment. The nozzle segment includes a prefired refractory block suited for insertion into the discharge bore of a ladle well block, and the lock ring segment includes a fastening means for removeably attaching the lock ring segment within the discharge bore of a ladle mounting plate. The nozzle segment and lock ring segment include cooperating tapered surfaces to provide a slip plane for compressing and extruding bonding material from between mortar joints of the two piece nozzle insert.
    Type: Grant
    Filed: March 3, 1993
    Date of Patent: August 9, 1994
    Assignee: Bethlehem Steel Corporation
    Inventors: Donald J. Idstein, John P. Hoffman, Harry J. Beesley
  • Patent number: 5327344
    Abstract: Instruments are often designed to operate in connection with a variety of machine types. Advantageously, the instrument is capable of modifying the appearance and function of its displays in response to the machine to which the instrument is connected. The subject invention includes a device for producing an identification code and a plurality of gauges for indicating levels of the sensed parameters. Each of the gauges has an outline segment for illustrating a range of levels of the sensed parameter indicated by the gauge and a symbol for identifying the sensed parameter indicated by the gauge. A controller receives the identification code and selectively enables one or more of the plurality of gauges and illuminates the outline segment and symbol associated with each of the enabled gauges in response to the identification code.
    Type: Grant
    Filed: September 16, 1992
    Date of Patent: July 5, 1994
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Ricky D. Vance, Dennis A. Barney, Joseph G. Kozlevcar
  • Patent number: 5321875
    Abstract: A centering tool for coaxially aligning a well block with a discharge bore of a steelmaking vessel, the centering tool comprising a support frame and a cluster of pivotable centering arms. Each centering arm includes a wedge shaped portion having a first edge adapted to engage a drive means, and a second edge having a first surface adapted to engage the wall of a bore extending through the well block, and a second surface adapted to engage the wall of the discharge bore of the steelmaking vessel. The drive means includes an expansion plug for engaging and pivoting centering arms positioned within the bore of the well block.
    Type: Grant
    Filed: June 22, 1993
    Date of Patent: June 21, 1994
    Assignee: Bethlehem Steel Corporation
    Inventors: John P. Hoffman, Alvin M. Nestler, Donald J. Idstein
  • Patent number: 5040119
    Abstract: Implement draft control devices are typically utilized on agricultural vehicles such as tractors and on other earthworking type vehicles. Advantageously, such control systems should respond quickly to changing soil conditions, while remaining stable so that the hitch and implement systems do not oscillate or are not changed in a rapid or erratic fashion. The instant embodiment of a draft control system includes a control system that receives hitch position control signals and engine acceleration signals, and controllably modifies the hitch position control signals in response to the rate of acceleration and deceleration of the engine. By utilizing engine acceleration and deceleration rates as opposed to mere changes in engine speed, the system is able to respond quickly to needed changes in implement depth while remaining stable during operation.
    Type: Grant
    Filed: April 5, 1990
    Date of Patent: August 13, 1991
    Assignee: Caterpillar Inc.
    Inventors: Gerald D. Hardy, John P. Hoffman, Larry E. Kendrick, Stephen W. Rector
  • Patent number: 4982315
    Abstract: A signal generator is provided for delivering non-overlapping charge and discharge signals to a voltage multiplier circuit. The multiplier circuit has a discharge switch for receiving the discharge signal and connecting a booster capacitor in series with an input voltage source and in parallel with a storage capacitor, thereby transferring charge from the booster capacitor to a storage capacitor. The multiplier circuit further includes charge switch which receives the charge signal and delivers the input voltage potential to the booster capacitor for charging. The signal generator advantageously provides an interval of time between the charge and discharge signals, thereby preventing sporadic discharges from the booster capacitor and undesirable power losses.
    Type: Grant
    Filed: March 19, 1990
    Date of Patent: January 1, 1991
    Assignee: Caterpillar Inc.
    Inventor: John P. Hoffman
  • Patent number: 4967309
    Abstract: A driver circuit for an inductive load, such as a solenoid winding, includes flyback and energization current sensors which respectively sense the current through the coil during flyback and energization. The flyback current sensor includes a flyback current resistor disposed in the flyback current path of the winding for producing a flyback signal proportional to the flyback current. The energization current sensor includes an energization current resistor disposed within the energization current path of the winding. The energization current resistor is adapted to produce an energization signal in response to the energization current flowing through the winding. Control of the solenoid winding is effected by a switch which connects and disconnects the winding from a power source in response to the duty factor of a control signal. A first summing amplifier receives the flyback and energization signals and produces an actual current signal in response to the received signals.
    Type: Grant
    Filed: December 26, 1989
    Date of Patent: October 30, 1990
    Assignee: Caterpillar Inc.
    Inventor: John P. Hoffman
  • Patent number: 4852657
    Abstract: Agricultural vehicles have heretofore lacked an adaptive implement hitch control and have correspondingly suffered from poor controllability of the hitch when the mass of the implement is varied significantly. The apparatus employs a sensor connected to and movable with the hitch such that a variable magnitude electrical signal is delivered which corresponds to the instantaneous hitch position. This signal is electronically differentiated to produce a signal indicative of actual hitch velocity. The hitch position and velocity signals are both used as feedback signals to close the control loop of the control and thereby provide an adaptive hitch velocity control.
    Type: Grant
    Filed: July 2, 1986
    Date of Patent: August 1, 1989
    Assignee: Caterpillar Inc.
    Inventors: Gerald D. Hardy, John P. Hoffman, Larry E. Kendrick
  • Patent number: D384341
    Type: Grant
    Filed: September 16, 1992
    Date of Patent: September 30, 1997
    Assignee: Caterpillar Inc.
    Inventors: John P. Hoffman, Dennis A. Barney, Joseph G. Kozlevcar