Abstract: A turning speed control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle to the right or left; a steering instructing device which can be displaced from a neutral position by operation and which instructs, according to the direction and distance of its displacement, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; and a control unit for performing a control such that when making the turning radius of the vehicle small by increasing the revolution speed of the steering motor according to the displacement of the steering instructing device detected by the displacement detector such that the crawler belts are driven with a relative travel difference therebetwe

Abstract: A control mechanism for a hydrostatic-mechanical power transmission system having a mechanical transmission unit driven through an input shaft connectable to a power source, and a hydrostatic transmission unit that is connectable to the input shaft and includes a pump and a motor each having a displacement setting swash plate. The control mechanism further includes a differential unit for connecting an output shaft to the mechanical transmission unit and the hydrostatic transmission unit to drive. At least either of the displacement setting swash plates is variable in angle.

Abstract: A steering system for use in a track-laying vehicle comprising: a steering motor that is forwardly and reversely rotatable and designed to drive crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a forward/reverse drive state detector for detecting whether the vehicle is in its forward drive state or reverse drive state; a lateral turn instructing device for instructing right turn or left turn of the vehicle; and a steering motor forward/reverse rotation control unit for determining the forward or reverse rotation of the steering motor in accordance with the forward or reverse drive state of the vehicle detected by the forward/reverse drive state detector, such that the vehicle turns to the right or left in response to a right turn instruction or left turn instruction released from the lateral turn instructing device.

Abstract: A turning system for use in a track-laying vehicle comprising: a power source; a steering motor driven by the rotation of the power source, for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a power source revolution speed detector for detecting the actual revolution speed of tile power source; and a steering motor control unit for performing a control such that, a target revolution speed set for the steering motor is decreased when the actual revolution speed of the power source detected by the power source revolution speed detector decreases below a target revolution speed set for the power source by a specified revolution speed or more.

Abstract: A turning control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, in accordance with its displacement direction and displacement distance, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; a vehicle speed detector for detecting the vehicle speed at which the vehicle moves forwards or backwards; and a steering motor revolution speed control unit for controlling the revolution speed of the steering motor such that the revolution speed of the steering motor becomes proportional to the vehicle speed detected by the vehicle spee

Abstract: A steering control system for use in a track-laying vehicle comprising: a power source; a steering motor driven by the rotation of the power source, for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, according to the direction and distance of its displacement, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; and a steering motor revolution speed control unit for obtaining a target steering motor revolution speed which is made proportional to the revolution speed of the power source based on the displacement of the steering instructing device detected by the displacement detector and controlling

Abstract: A mechanical - hydraulic transmission for a crawler-type vehicle is provided having a reduced dimension in a widthwise direction perpendicular to input/output shafts and capable of ready installation on an existent crawler steering device. The transmission is arranged such that a power input shaft (1), directly connected to a prime mover, an intermediate shaft (9) and an output shaft (19), are concentrically related and arranged in a longitudinal column. Normal- and reverse-rotation planetary gear devices (5, 6), having respective clutches (7, 8) thereof, are mounted on a periphery of the power input shaft (1), and the power input shaft (1) is connected to a variable displacement hydraulic pump (2).

Abstract: A transmission and control mechanism for a hydrostatic-mechanical power transmission system, provided with a mechanical transmission driven through an input shaft connected to a engine, a hydrostatic transmission connected to the input shaft, and a differential unit for connecting an output shaft to the mechanical and hydrostatic transmissions. The hydrostatic transmission includes a swashplate type pump and motor, with at least one of the swashplates being variable in angle. There is an engine revolution speed sensor, a target motor speed ratio setting device for setting a target motor speed ratio based on whether the engine speed is above, below or within a predetermined speed range, and a swashplate angle controller for controlling the swashplates according to the target motor speed ratio.

Abstract: The present invention relates to a method for controlling a power output of an engine of a crawler vehicle; such as, large sized bulldozers, at a time when shoe slip of such crawler vehicle occurs in operation, the crawler vehicle being provided with working equipments; such as, dozing units or blades, ripping units or rippers or the like. More particularly, the present invention relates to an adaptive engine power output mode setting method for automatically keeping the engine of the crawler vehicle in an optimum power output condition according to rates of the shoe slip or shoe slip rates of the crawler vehicle.

Abstract: At the time of starting movement as well as at the time when a crawler type tractor, e.g., a bulldozer for performing a dosing operation and a ripping operation is held in a three-point grounding state, an output from an engine (10) is automatically reduced further from a normal cut-off state, whereby an operator is not required to depress a deceleration pedal (13). Consequently, a burden to be borne by him can be reduced substantially.

Abstract: This invention relates to a method and apparatus for controlling shoe slip of a crawler vehicle directed to automatically prevent an endless track from slipping beyond the state where maximum pulling force is attained thereby liberating an operator from troublesome operations requiring a high level of skill. The shoe slip control method is accomplished by switching the operation mode to a predetermined engine output mode when a shoe slip ratio exceeds a predetermined value during the operation of the vehicle.

Abstract: An exhaust purification system has an upstream exhaust gas sensor and a downstream exhaust gas sensor disposed downstream of a catalytic device. Each sensor detects an oxygen concentration in exhaust gases and provides an output which inverts between a lean state, representative of a lean air/fuel ratio, and a rich state, representative of a rich air/fuel ratio, according to oxygen concentrations. The upstream exhaust sensor is determined to have deteriorated when an output from the upstream exhaust sensor is kept in a predetermined correlation with an output from the downstream exhaust sensor while the output from the downstream exhaust sensor remains the same.

Abstract: The present invention relates to a method for controlling a power output of an engine of a crawler vehicle; such as, large sized bulldozers, at a time when shoe slip of such crawler vehicle occurs in operation, the crawler vehicle being provided with working equipments; such as, dozing units or blades, ripping units or rippers or the like. More particularly, the present invention relates to an adaptive engine power output mode setting method for automatically keeping the engine of the crawler vehicle in an optimum power output condition according to rates of the shoe slip or shoe slip rates of the crawler vehicle.

Abstract: A vehicle equipped with four-wheel drive has a transfer case including a center-differential which delivers driving power to both front and rear axle assemblies when needed and is shiftable between a two-wheel and a four-wheel drive mode of operation and between a differential-locked and a differential-unlocked drive mode of operation. A free wheeling drive mechanism with a clutch member is incorporated in an output shaft of an axle differential in association with wheels non-driven in the two-wheel drive mode of operation and is adapted to disconnect when the vehicle is in the two-wheel drive mode of operation. A controller causes a forced drive mode shift of the center-differential from the four-wheel differential-underlined drive mode of operation either to the four-wheel differential-locked or to the two-wheel drive mode of operation when the disconnection of the free-wheeling drive mechanism is detected while the vehicle is in the four-wheel differential-unlocked drive mode of operation.

Abstract: A control device for a power shovel having a first boom, a second boom and an arm rotatable around the longitudinal axis of the arm, detects the angle of the arm with respect to the horizontal plane based on the posture angles of the first and second booms and the arm, and controls the arm cylinder such that the angle of the arm with respect to the horizontal plane is held to a reference angle. Further, the control device detects a deviation angle between the current direction and the initial directions and controls the revolution angle of the arm so as to make the deviation angle zero. Furthermore, the control device designates a moving direction of the connection point between the second boom and the arm along a plane including the first boom, the second boom and the arm, and controls cylinders for the booms such that their connection point may be moved in the moving direction thus designated.

Abstract: A turning control system for use in a track-laying vehicle comprising: a steering motor for driving crawler belts provided at both sides of the vehicle such that a relative travel difference is caused between the crawler belts, thereby turning the vehicle rightwards or leftwards; a steering instructing device which can be displaced from a neutral position by operation and which instructs, in accordance with its displacement direction and displacement distance, a turning direction and a turning radius for the vehicle, the turning radius decreasing as the displacement distance increases; a displacement detector for detecting the displacement of the steering instructing device; a vehicle speed detector for detecting the vehicle speed at which the vehicle moves forwards or backwards; and a steering motor revolution speed control unit for controlling the revolution speed of the steering motor such that the revolution speed of the steering motor becomes proportional to the vehicle speed detected by the vehicle spee