Abstract: A hydraulic system is disclosed having at least two hydraulic circuits. The disclosed system apportions flow between the two hydraulic circuits based on an assumed flow rate that is held constant in both power-limited and non-power-limited conditions.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: A method of loading a truck with material using a loader includes a step of determining a target load for a final pass. Material is loaded into a bucket of the loader in excess of the target load. Excess material is dumped from the bucket back to the pile in a controlled manner to arrive at a target load of reposed material in the bucket. The target load amount of the material in the bucket, which is less than a total amount of material originally loaded in the bucket is dumped into the truck by pitching the bucket. The bucket may be pitched to a determined pitch angle that is based upon the target load using an appropriate material curve stored on the loader. The pitch control algorithm can be calibrated by sensing the reposed weight of material in the bucket, and comparing that to an expected reposed weight, and then updating one of the material curves if there is a deviation.

Abstract: A cylinder assembly is disclosed. The cylinder assembly may include a cylinder body having an internal cavity therein and a piston and rod assembly disposed for axial movement within the internal cavity of the cylinder body. The piston and rod assembly may have an axial passage extending therein. The cylinder assembly may further include a tubular element received within the axial passage of the piston and rod assembly. At least a portion of the tubular element may extend out of the axial passage and into the internal cavity of the cylinder body between the axial passage and a wall of the cylinder body.

Abstract: A steering system for a machine having at least one steerable traction device is disclosed. The steering system may have a steering actuator operatively connected to the at least one steerable traction device, and a travel speed sensor configured to generate a signal indicative of a travel speed of the machine. The steering mechanism may also have an operator input device having a deadzone. The deadzone may vary in response to the signal. The steering system may also have a controller in communication with the steering actuator, the operator input device, and the travel speed sensor. The controller may be configured to affect operation of the steering actuator in response to operation of the operator input device only when the operation of the operator input device deviates from the deadzone.

Abstract: A cylinder assembly is disclosed. The cylinder assembly may include a cylinder body having an internal cavity therein and a piston and rod assembly disposed for axial movement within the internal cavity of the cylinder body. The piston and rod assembly may have an axial passage extending therein. The cylinder assembly may further include a tubular element received within the axial passage of the piston and rod assembly. At least a portion of the tubular element may extend out of the axial passage and into the internal cavity of the cylinder body between the axial passage and a wall of the cylinder body.

Abstract: A method and apparatus for detecting the position of a rod member of a cylinder assembly are provided. The cylinder assembly may have a cylinder body with a cylinder chamber therein, a gland member disposed within the cylinder chamber, and a rod member movably arranged within the cylinder chamber and a rod opening of the gland member. The method may include moving the gland member within the cylinder chamber to substantially align a gland aperture of the gland member with a cylinder aperture of the cylinder body; substantially fixing the gland member relative the cylinder body; positioning a position sensor within at least one of the cylinder aperture and the gland aperture; moving the rod member within the rod opening of the gland member and the cylinder chamber of the cylinder body; and operating the position sensor to detect the position of the rod member.

Abstract: A method and apparatus for detecting the position of a rod member of a cylinder assembly are provided. The cylinder assembly may have a cylinder body with a cylinder chamber therein, a gland member disposed within the cylinder chamber, and a rod member movably arranged within the cylinder chamber and a rod opening of the gland member. The method may include moving the gland member within the cylinder chamber to substantially align a gland aperture of the gland member with a cylinder aperture of the cylinder body; substantially fixing the gland member relative the cylinder body; positioning a position sensor within at least one of the cylinder aperture and the gland aperture; moving the rod member within the rod opening of the gland member and the cylinder chamber of the cylinder body; and operating the position sensor to detect the position of the rod member.

Abstract: A hydraulic control system having a pump for delivering fluid under pressure from a fluid reservoir, a hydraulic actuator selectively driven by the fluid, the system comprises a main flow control valve connected between the pump and the actuator for selectively providing the fluid to and from the actuator, and a control unit connected to the main flow control valve for controlling operation of the main flow control valve to control the rate of change of the area of the main flow control valve relative to the delivery of fluid from the pump, and the control unit connected to the pump to increase or decrease the actual pump command proportional to the inverse of the pump command.

Abstract: Apparatus and methods for controlling the resistance to the movement of a steering shaft that is operable to move as a function of an operator input. A position sensor is coupled with the steering shaft and transmits a shaft position signal as a function of the position of the steering shaft. A processing device is coupled with the position sensor to receive the shaft position signal and transmits a resistance signal as a function of the shaft position signal. A resistance device is coupled with the processing device to receive the resistance signal and is coupled with the steering shaft, the resistance device resists the movement of the steering shaft as a function of the resistance signal.

Abstract: A control system and method for detecting and inhibiting an impending full saturation condition in a hydraulic system of a work machine wherein the hydraulic system includes a hydraulic pump for supplying fluid under pressure to the hydraulic system and a plurality of control valves for controllably passing fluid from the pump to a plurality of work elements, the present control system including an electronic controller coupled to both an operator input device actuatable to control the operation of the work elements and a plurality of control valves for controlling the fluid flow to the work elements, the controller being operable to determine the actual margin pressure of the hydraulic pump in response to comparing the pump pressure to the pressure of the heaviest loaded work element requested by an operator through the actuation of the operator input device and to compare the actual margin pressure to the established margin pressure for the pump.

Abstract: A method and apparatus for controlling a mobile machine during start-up. The mobile machine has a prime power source, a means for transport, and at least one auxiliary system; the means for transport and the at least one auxiliary system are controllably driven by the prime power source. The method and apparatus includes determining an actual angle of steering of the mobile machine, comparing the actual angle of steering with a desired angle of steering, starting the prime power source, enabling engagement of the at least one auxiliary system, and disabling engagement of the means for transport in response to the difference between the actual angle of steering and the desired angle of steering being greater than a predetermined threshold value.

Abstract: A control scheme is provided that controls the maximum pressure level in desired locations of a hydraulic system. This control scheme eliminates the need of separate line relief valves that many times create pressure spikes in the hydraulic system. In one example, the control scheme functions to sense the operating pressure at the desired location and compares it to a differential pressure and a desired input command during one step or loop to establish a predicted pressure level. The predicted pressure level is compared to the pressure necessary to initiate movement of the valving element in an electrically actuated control valve mechanism. The result is used to move the valving element to a predetermined position if the predicted pressure level is less than cracking pressure level and the differential pressure is greater than zero.

Abstract: The invention is an apparatus for determining a valve transform curve in a fluid system. The fluid system has a valve and a fluid actuator arranged to initiate movement of a load. The invention includes a desired velocity manager, a load responsive device, and a valve transform curve manager. The desired velocity manager determines a desired velocity of the load. The load responsive device determines a characteristic of the load, such as weight or position. The valve transform curve manager receives responsively determine a valve transform curve based on the desired velocity and load characteristic.

Abstract: A control system is typically used for controlling the implements of a machine. The control system includes a lift circuit and a tilt circuit. The control system includes a module which receives a signal from the lift circuit and the tilt circuit and selects a signal for controlling a valve to meter pump-to-cylinder fluid flow.

Abstract: A method and apparatus for providing control of multiple actuators with a single control lever is provided. The method and apparatus is adapted for use in an electro-hydraulic system having a microprocessor, multiple actuators, respective electro-hydraulic directional control valves for each actuator, and individual control levers operatively associated with the microprocessor for controlling movement of the respective electro-hydraulic directional control valves. The method and apparatus is accomplished by providing a switch on each of the control levers that is operational to condition the microprocessor to direct simultaneous signals to the respective electro-hydraulic directional control valves to control each of the multiple actuators in proportion to the degree of movement of the one actuator when the switch thereon is depressed.

Abstract: An apparatus for indicating efficiency losses in a pump is provided. The apparatus includes a temperature sensor located at the pump input, a second temperature sensor located at a second location, a fluid flow sensor located at the second location, a processor for producing a difference signal in response to signals from the first and second temperature sensors and for quantifying efficiency losses of the pump in response to the difference signal and a signal from the fluid flow sensor. A fault indicator is also provided that is responsive to the efficiency losses.