1
Robert G Miller, Allen D Myers, Weldon L Phelps, Alfred W Sieving: Method and apparatus for controlling differentially driven wheel slip. Caterpillar Tractor Co, Krass Young & Schivley, August 10, 1982: US04344139 (63 worldwide citation)

A slip control system for vehicles having spaced apart differentially driven wheels (200,202) including means (220) for calculating wheel slip according to the ratio of wheel speeds, means (242,230,232) for entering a slip control mode wherein a braking force is applied to the slipping wheel and inc ...


2
Robert G Miller, Weldon L Phelps: Failsafe wheel slip control system and method of operating same. Caterpillar Tractor Co, Krass & Young, November 30, 1982: US04361871 (54 worldwide citation)

A slip control system for vehicles having spaced apart drive wheels (200,202) driven by an input shaft (204) through a differential unit (206) including means (220) for calculating wheel slip according to the ratio of wheel speeds, means (220,230,232) for entering a slip control mode wherein a braki ...


3
Weldon L Phelps, Alan L Stahl: Multiple threshold wheel slip control apparatus and method. Caterpillar Tractor Co, Stephen L Noe, June 4, 1985: US04521856 (37 worldwide citation)

Anti-wheel spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems operate automatically and not be unduly influenced by false slip signals caused by steering of the vehicle. It is further desirable that the operability of the control be readi ...


4
James P Mueller, Weldon L Phelps: Clutch brake steering control. Caterpillar, Terry D Morgan, October 27, 1987: US04702358 (33 worldwide citation)

Clutch-brake steering systems are known to operate on track vehicles which are highly reliable and cost effective, but lacked the fine degree of controllability found in the more expensive differential steering. An electronically controlled clutch-brake steering control apparatus provides control si ...


5
Javad Hosseini, Eric A Hutchison, Randall M Mitchell, Weldon L Phelps, James E Schimpf: Method and apparatus for controlling an implement. Caterpillar, Steven R Janda, March 2, 1993: US05189940 (27 worldwide citation)

Vehicles having implements are typically used to perform repetitive functions in work cycles. An implement control system raises and lowers an implement relative to the vehicle and reduces the stresses applied to the vehicle from abruptly stopping the motion of the implement. A lever pilot signal is ...


6
John P Hoffman, Weldon L Phelps: Dual current sensing driver circuit. Caterpillar, Terry D Morgan, April 28, 1987: US04661766 (27 worldwide citation)

A hybridized solenoid driver circuit includes a first and second current sensing resistor. The first current sensing resistor is disposed within the flyback current path of the windings of an electrically actuated solenoid and provides a signal proportional to the flyback current only. Control of th ...


7
Weldon L Phelps: Pulse width modulated constant current servo driver. Caterpillar Tractor Co, Krass & Young, February 15, 1983: US04373697 (21 worldwide citation)

A method and apparatus for controlling a coil (40) operated hydraulic valve (48) employs a constant current source (36) to consistently control valve response (P.sub.o) irrespective of variations in power supply voltage and coil resistance (R.sub.c). A switching circuit (58) controls the delivery of ...


8
Gregory L Williamson, Larry E Kendrick, Weldon L Phelps: Fault tolerant serial communications network. Caterpillar, Stephen L Noe, February 16, 1993: US05187709 (16 worldwide citation)

A communications network is adapted to provide communication between control modules on a vehicle. Each control module includes a first and second transceiver. A control module checks for the presence of a data message from another control module before transmitting a data message. If there is no ot ...


9
Weldon L Phelps, Alan L Stahl, Giles K Sorrells: Anti-spin control apparatus and method. Caterpillar, Stephen L Noe, May 17, 1988: US04745552 (11 worldwide citation)

Anti-spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems exhibit rapid response to adverse working conditions, and be capable of quickly applying braking forces to whichever driven wheel is rotating at a higher velocity at a given time. Th ...


10
Val G Boucher, Weldon L Phelps, Daniel R Ekstrand: Electrical transmission control mechanism. Caterpillar, Charles E Lanchantin Jr, June 5, 1990: US04930366 (9 worldwide citation)

An electrical transmission control mechanism includes first and second control members which are individually limitedly rotatable to respectively select the directional and neutral modes or the speed ratio modes of a transmission. First and second electrical rotary type switching devices which are r ...