Randall D Mitchell

US Patent:

45238928, Jun 18, 1985

Filed:

May 14, 1984

Appl. No.:

6/609676

Inventors:

Randall M. Mitchell - Washington IL
John T. Armstrong - Chillicothe IL

Assignee:

Caterpillar Tractor Co. - Peoria IL

International Classification:

F04B 4900
F04B 126

US Classification:

417 34

Abstract:

An apparatus for controlling both pump displacement of a variable displacement hydraulic pump and the quantity of fuel delivered to an internal combustion engine for the purpose of delivering a requested hydraulic flow at a highly efficient operating point. The apparatus includes an underspeed control means for reducing pump displacement in response to the operating speed of the engine lugging below a desired operating speed. Additionally, a fuel control means operates to reduce the quantity of fuel delivered to the engine in response to the operating speed of the engine rising above the desired operating speed.

US Patent:

54563330, Oct 10, 1995

Filed:

Mar 25, 1993

Appl. No.:

8/037045

Inventors:

Chris D. Brandt - Peoria IL
Michael F. Coffman - Metamora IL
Randall M. Mitchell - Washington IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

B60K 2302

US Classification:

180336

Abstract:

An electrohydraulic control device for a drive train of a vehicle including an engine, a transmission, a source of pressurized fluid, and an input clutch driving connected between the engine and the transmission. The device includes a control lever or handle having a control member progressively manually movable between first and second positions, wherein the transmission is adapted to responsibly shift between a FORWARD and a REVERSE gear ratio in response to movement of the control member from the first position to the second position. An electronic control module is adapted to determine a transmission clutch relative speed as a function of the transmission output speed and the transmission input speed and responsively engage and disengage the input clutch during a directional shift.

US Patent:

55803326, Dec 3, 1996

Filed:

Apr 13, 1995

Appl. No.:

8/421724

Inventors:

Randall M. Mitchell - Washington IL
Todd D. Creger - Metamora IL
James R. Talbott - Westborough MA
Gregory L. Williamson - Metamora IL
Richard B. League - Peoria IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F16H 6104

US Classification:

477143

Abstract:

The present invention is directed toward determining when a clutch of an automatic transmission substantially fills with fluid. Once it is accurately determined when a clutch fills with fluid, then control over the transmission shifting may reliably be performed. The present invention determines when an on-coming speed clutch substantially fills with fluid in response to determining when an off-going speed clutch releases. Further, the present invention determines when an on-coming direction clutch substantially fills with fluid in response to determining when the torque converter output torque suddenly changes.

US Patent:

54939283, Feb 27, 1996

Filed:

Oct 14, 1994

Appl. No.:

8/323527

Inventors:

Randall M. Mitchell - Washington IL
Ashok Kajjam - Peoria IL
Alan L. Stahl - Peoria IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

F16H 6112

US Classification:

74335

Abstract:

A diagnostic system is provided for responding to a fault condition in a transmission having an electronic control including diagnostics for both electrical and mechanical failures, said diagnostics indicating the affected clutch and the type of failure. The diagnostic system includes a processor for selecting a first table of available gears in response to the affected clutch and a first subset of electrical and mechanical failure types being diagnosed and for selecting a second table of available gears in response to the affected clutch and a second subset of electrical and mechanical failure types being diagnosed.

US Patent:

45347077, Aug 13, 1985

Filed:

May 14, 1984

Appl. No.:

6/609675

Inventors:

Randall M. Mitchell - Washington IL

Assignee:

Caterpillar Tractor Co. - Peoria IL

International Classification:

F04B 4900

US Classification:

417 34

Abstract:

An apparatus for regulating the speed of internal combustion engine of a hydrostatic system. A fuel control means acts to control the quantity of fuel delivered to the engine responsive to the immediate hydraulic flow demanded by operation of the hydrostatic system. The speed of the engine is set to one of a plurality of discrete levels in response to the required flow being within one of a corresponding plurality of preselected ranges.

US Patent:

61156612, Sep 5, 2000

Filed:

Apr 9, 1998

Appl. No.:

9/057567

Inventors:

Javad Hosseini - Edelstein IL
Randall M. Mitchell - Washington IL
Ashok Kajjam - Peoria IL
Alan L. Stahl - Peoria IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

G06F 1700
G06F 1900

US Classification:

701 51

Abstract:

In one aspect of this invention, a fluid actuated clutch is disclosed. The fluid actuated clutch is operatively connected to a control valve that is actuated by an electronic controller that receives a signal from an input mechanism, including a value for speed of an engine drive and a value of output speed for a torque converter. The method includes detecting a torque converter ratio which is the output speed of the torque converter divided by the engine drive speed, and detecting if there is at least one torque converter decrease exceeding a predetermined level and preferably detecting if there are at least two consecutive decreases in the torque converter ratio with at least one of the torque converter decreases exceeding a predetermined minimum level. This condition represents the end-of-fill point for the fluid actuated clutch.

US Patent:

53056574, Apr 26, 1994

Filed:

May 11, 1992

Appl. No.:

7/881279

Inventors:

Steven C. Bray - Metamora IL
Daniel C. Wood - East Peoria IL
Randall M. Mitchell - Washington IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

B60K 4112

US Classification:

74861

Abstract:

An apparatus is provided for use in a vehicle having an engine driven transmission which includes a plurality of gear ratios. The apparatus includes a sensor adapted to sense a parameter indicative of vehicle speed and responsively produce a vehicle speed signal. A downshift switch is provided to controllably produce a downshift signal. An engine speed sensor senses engine speed and responsively produces an engine speed signal. A controller is adapted to receive the vehicle speed, engine speed, and downshift signals, process the vehicle speed signal to produce a transmission control signal, produce a down shift enable value as a function of the engine speed signal, and modify the transmission control signal to correspond to a lower gear ratio in all but the lowest gear ratio when the downshift signal is received and a value responsive to the vehicle speed signal is less than the down shift enable value signal. An actuator is adapted to receive the transmission control signal and responsively control the transmission gear ratio.

US Patent:

50406485, Aug 20, 1991

Filed:

Nov 5, 1990

Appl. No.:

7/608868

Inventors:

Randall M. Mitchell - Washington IL
David W. Bump - late of Morton IL
Michael F. Coffman - Metamora IL
Dwight S. Holloway - Chillicothe IL
Lowell E. Johnson - East Peoria IL
Tony L. Marcott - Peoria IL
Philip C. McKenzie - Peoria IL
Noel J. Rytter - Peoria IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

B60K 4128

US Classification:

192 358

Abstract:

A vehicle such as an earthmoving wheel loader has an engine, a torque converter having an impeller element, a reactor element and a turbine element, and an input clutch connected between the engine and the impeller element. An electrohydraulic control device is provided to controllably engage the input clutch and that includes a microprocessor-based electronic control module, an actuator mechanism having a control member that is progressively movable between first, second and third positions to deliver a first electrical signal to the electronic control module, and a valve for directing fluid to the input clutch at a decreasing pressure level when the control member is moved from the first to the second positions in response to another signal from the electronic control module. The electronic control module is programmed to maintain at least a minimal pressure level to the actuating piston of the input clutch when the control member is between the second and third positions. Moreover, a service brake is increasingly engaged by a service brake mechanism in response to the control member moving between the second and third positions.