Abstract: This self-propelled articulation-steered tractor has a positive adjustment system for controlling the orientation (both elevation and lateral tilt) of a transverse implement mounted on either the front or rear assembly of the tractor, and a reactive adjustment system for allowing terrain-responsive orientation of the axle of the other assembly (front or rear) not carrying the transverse implement. The positive adjustment system is operator controlled. The reactive system may comprise a mounting of the axle for the non-implement-carrying assembly so it freely pivots with respect to the frame of that assembly. An articulation joint transverse swivel pivot system is provided for lateral tilt movement between the front and rear assemblies of the articulation-steered tractor.

Abstract: A vehicle height control apparatus for a vehicle is comprised of a fluid chamber installed for each wheel. The fluid chamber changes the vehicle height by receiving or discharging the fluid supplied from a fluid supply source. The vehicle height control apparatus operates to decrease the difference between right and left vehicle heights when the difference between the right and left vehicle heights is greater than a predetermined value, the vehicle is in a parked condition, and the fluid supply source cannot supply the fluid to the fluid chamber. The operation by the apparatus is carried out such that the right and left fluid chambers are communicated with each other.

Abstract: A leveling system for a combine having a transaxle. The leveling system comprises a three point linkage coupling the transaxle to the supporting structure of the combine. The first and second links of the three point linkage are coupled to the underside of the transaxle. The third link is coupled to the top of the transaxle. A transverse sway bar is positioned between the supporting structure and the transaxle. Two hydraulic cylinders are mounted between the first and second links and the supporting structure for manipulating the angle of inclination of the transaxle relative to the supporting structure.

Abstract: A system for leveling a vehicle, such as a recreational vehicle, includes three extendable and retractable fluid-operated jacks. The jacks are spring-biased to their retracted position. Supply of hydraulic fluid under pressure extends the jacks, and the jacks are retracted by relieving the supply of hydraulic fluid pressure to the jacks to allow the springs to expel fluid from the jacks. A number of unique aspects are incorporated in the leveling system for providing highly advantageous construction, operation and installation.

Abstract: An active suspension system for an automotive vehicle is arranged to regulate the attitude of a vehicle body in a flat or balanced state by controlling hydraulic cylinders respectively disposed between a vehicle body and a road wheel, in response to an attitude change of the vehicle body. The active suspension system comprises electromagnetically operated variable vibration attenuation valves, each of which is fluidly connected with each hydraulic cylinder and is followed by an accumulator. Each variable vibration attenuation valve is adapted to be variable in its attenuation constant in response to a vertical acceleration experienced by the road wheel. The variable vibration attenuation valve takes on a low attenuation constant to maintain a high riding quality of the vehicle under a normal cruising condition, and a high attenuation constant to suppress the response of the road wheel under a rough road cruising condition.

Abstract: An automatic leveling system for a four-wheel vehicle system having outrigger assemblies at each of the four corners of the vehicle chassis and in which each outrigger assembly has an outrigger pad and a hydraulic cylinder for moving the pad downwardly and upwardly relative to the ground. The leveling system includes a low-pressure high-flow source of hydraulic fluid which is connected for one-way flow into the head ends of all four of the cylinders to lower all pads to the ground and then maintain them in contact with the ground. A level sensor senses the relative levelness of the right front and left rear corners of the vehicle and high-pressure low-flow hydraulic fluid is connected to the head end of the cylinder at the lower of those two corners to raise that corner of the vehicle relative to the ground.

Abstract: A system for automatically leveling a vehicle, such as a recreational vehicle installed with a plurality of extensible jacks and disposed at strategic positions on the vehicle underside, and responsive to an automatic level control electronics to extend simultaneously all of the jacks and at different speeds as determined by the angle of vehicle versus gravity and bring vehicle to a level condition. The jacks are stopped when they are use higher current than that used before the jacks contact the ground, to assure ground contact, and the vehicle is level.

Abstract: A device for suspension of a driver's cab (2) in relation to chassis (1) of a motor vehicle includes four hydraulic cylinders (5a-5d), each consisting of a hollow body connected to the chassis. A piston (9) slides axially in each body and delimits an upper chamber (10) and a lower chamber (11) therein. Each piston is integral with a first rod (12) connected to the cab and with a second rod (13) connected to the chassis. Ducts (17a-17d) are filled with virtually incompressible fluid and connect the upper chamber of a given cylinder to the lower chamber of the cylinder which is diagonally opposite thereto.

Abstract: A vehicular height controlling arrangement changing a length of a suspension cylinder by supplying or draining the hydraulic oil through a damping force selector valve. The damping force selector valve changes a damping force of a suspension cylinder by changing an orifice therein. When the vehicular height is lowered under a vehicle stopping condition, a large orifice is selected in the damping force selector valve so as to quickly lower the vehicular height. Thereafter, a small orifice is immediately selected to suppress the swinging of the automotive vehicle.

Abstract: The vehicle is supported on the ground by tiltable propulsion units carried by a vehicle body. The vehicle includes force sensors for forming force signals representative of the forces applied to each propulsion unit from the vehicle body. Support signal forming means receive and process these force signals to form support signals representative of the support forces applied to the propulsion unit by the ground. The invention is particularly applicable to the nuclear industry.

Abstract: A vehicle having a suspension control system that is especially applicable to an aircargo transport loader which is adapted for storage in a cargo hold of an aircraft. The suspension control system utilizes sensors to monitor the clearance between the vehicle and an underlying or overlying surface such as the ramp leading into a cargo hold or the roof of the cargo hold. The sensors relay information concerning clearance to a central control where the necessary suspension adjustments are made to allow the vehicle to avoid a clearance problem once travel is continued after stopping for the suspension adjustment. The system allows for suspension adjustments to be made either automatically or manually. The invention also includes an under deck support system which allows for limited pitch, yaw, roll and side to side adjustments to be made to the deck with respect to the underlying base frame.

Abstract: An active suspension system for use with a mass suspended relative to a movable structure and subject to external forces such as the chassis of off-road vehicles, and in particular the hull of heavy combat vehicles, has a passive hydropneumatic suspension system (PHSS) connected to a servopump and an accumulator, and wherein the servopump transfers fluid energy between the accumulator and the suspension system, in accordance with sensed operating conditions which are inputted to a processor whose output commands the velocity of the servopump to control the pressure and volume relationships of the PHSS and accumulator to improve the ride of said vehicle and to substantially reduce energy requirements when operating off-road.

Abstract: An apparatus for controlling the lateral disposition of a guide roller of a traveling service unit on a textile machine is provided. The apparatus includes a first support wheel rotatably mounted on the traveling service unit and an adjustable wheel assembly. The adjustable wheel assembly includes a second support wheel laterally spaced from the first support wheel, a device for rotatably mounting the second wheel to the traveling service unit and a device for selectively adjusting the vertical displacement of the second wheel relative to the traveling service unit to maintain the guide roller at a predetermined disposition relative to a guide surface of the textile machine. The device for selectively adjusting the vertical displacement of the second wheel includes, in one aspect of the invention, a cylinder and piston assembly and, in another aspect of the invention, a pair of bell cranks interconnected to one another by a cylinder and piston assembly.

Abstract: A vehicular height control system, according to the invention employs mutually different first and second target vehicular heights, about which normal vehicular height range is determined. The first target height is used during normal vehicle driving conditions, in which the power is supplied. On the other hand, the second target height is used during vehicular parking. The vehicular height control system according to the invention is responsive to turning OFF of the power supply to perform height adjustment utilizing the second target height to sligthly raise the vehicular height and maintains the raised height during parking. In order to maintain the vehicular height at a slightly higher level, slightly greater suspension force than that required for maintianing the vehicular height at a height level in the normal driving condition is provided. This reduces height adjustment when power supply is resumed.

Abstract: A cross-country vehicle includes a mobile chassis and a superstructure carrying a driver's cab wherein the superstructure is mounted on the chassis for tilting movement about a horizontal axis and a transverse axis and wherein a hydraulic cylinder on each side of the longitudinal axis acts between the chassis and the superstructure to tilt the superstructure about either or both axes in order to position the superstructure horizontally as the vehicle moves over rough ground.

Abstract: According to the present vehicle height control system, vehicle height adjustment does not begin unless the difference found between outputs of any two of sensors is within a predetermined range, each of which detects a height between a rotating center of a corresponding wheel and a body of the vehicle. Thus, upon the occasion of any one of the following events, the vehicle height adjustment may not be performed unnecessarily: (1) a vehicle is parking with its engine operating in such a manner that any one of its wheels is run onto the sidewalk which is considerably higher than a road surface, (2) a body of a vehicle is jacked-up at a position near any one of the wheels in a service shop, or (3) any one of the wheels has fallen into a gutter or pothole along a road and the engine is operating.

Abstract: Modular element of module (M) for an articulated vehicle formed therefrom. The vehicle must be able to travel over various obstacles (corridors, staircases, level changes). The modules (M) are joined by double hinges (20) and have internal degrees of freedom (flexible chassis, twisting displacement, adjustment of the pitch of the load 69), so that the vehicle is given flexibility and stability. The vehicle is intended to operate in hostile or dangerous environments.

Abstract: A vehicular height regulating system monitors a vehicular height level. The monitored height level is compared with upper and lower criteria which are higher than and lower than a predetermined target height level in a given magnitude. The system generally performs height adjustment for rising or lowering the actual vehicular height when the monitored vehicular height is out of a target height range defined by the upper and lower criteria. The system also monitors an a preselected vehicular driving parameter which reflects vehicular running condition. The system adjusts the upper and lower criteria depending upon the monitored vehicular driving parameter.

Abstract: A suspension control apparatus for an automotive vehicle has a plurality of suspension units which are disposed between each of the wheels of the vehicle and the vehicle body. An acceleration sensor measures the lateral acceleration of the vehicle body. A contol unit corrects the output of the acceleration sensor for drift of the neutral point of the sensor from a prescribed value. Based on the corrected output, the control unit controls the suspension units so as to suppress rolling of the vehicle body.

Abstract: The suspension system of the present invention includes an elongated spring having one end attached to the vehicle frame and having a second end. A pneumatic bag includes an upper end which is attached to the vehicle frame and a lower end. A securing bracket attaches the lower end of the bag and the second end of the elongated spring to the axle so that the weight of the vehicle frame above the axle is supported in combination by the spring and the air bag. A pneumatic control system is in communication with the bag for selectively introducing air to the bag so as to control the pressure within the bag and thereby control the height that the bag supports the vehicle frame above the axle. A stabilizer bar is pivotally connected at one end of the vehicle frame and at the other end to the axle so as to cause the vehicle frame to be centered over the axle while at the same time permitting the vehicle frame to move vertically with respect to the axle.

Abstract: An integrated roll rigidity and differential slip control system for a wheeled vehicle comprises roll rigidity changing means for changing roll rigidity distribution to front and rear wheel sides, roll rigidity control means for controlling the operation of said roll rigidity changing means based on vehicle running conditions, a differential interposed between the rear wheels, clutch means for supplying a slip limiting force to the differential to limit differential action thereof, and slip control means for controlling engagement of the clutch means based on vehicle running conditions and integrated control means for controlling, in preference to the control by the roll rigidity control means, the roll rigidity distribution in such a way that a roll rigidity is larger on the front wheel side and smaller on the rear wheel side in response to a cornering condition in which a driving force is distributed more to a cornering outside driving wheel than to a cornering inside driving wheel.

Abstract: An improved method and means for control and accomplishment of semi-active damper means transition between high damping and low damping states is provided which takes advantage of the available inherent dynamic fluid pressure forces produced by the condition of motion between supported and supporting members. Deferral or delay of damper state transitions to avoid force discontinuities or system noise is accomplished mechanically, or automatically internal to the structure of the adjustable valve means. The delay of damper state transition from high to low and low to high damping is accomplished independent of the particular control policy utilized until the fluid pressure differential across the valve ring members is a preselected low value. Commanded valve switching and motion condition sensing requirements are also minimized by reversible check valve means.

Abstract: A vehicle leveling strut of the type having a direct-acting hydraulic shock absorber provided with a reciprocable piston rod having a dirt shield mounted thereon. A tubular rolling diaphragm member secured at one end to the shock absorber and to the opposite end to the dirt shield and defining therewith a variable volume chamber adapted to be selectively pressurized and de-pressurized for controlling the distance between the sprung and unsprung portions of an associated vehicle. Located interiorly of the pressurizable chamber and concentrically positioned between the shock absorber and fixedly mounted to the dirt shield is a generally tubular support member upon which is mounted at least one pair of electrical coil windings for sensing changes in the electromagnetic field of each coil winding.

Abstract: An active suspension system for use with a mass suspended relative to a movable structure and subject to external forces such as the chassis of off-road vehicles, and in particular the hull of heavy combat vehicles, has a passive hydropneumatic suspension system (PHSS) connected to a servopump and an accumulator, and wherein the servopump transfers fluid energy between the accumulator and the suspension system, in accordance with sensed operating conditions which are inputted to a processor whose output commands the velocity of the servopump to control the pressure and volume relationships of the PHSS and accumulator to improve the ride of said vehicle and to substantially reduce energy requirements when operating off-road.

Abstract: Disclosed is a level regulator for automotive vehicles, including a hydraulically operating level adjusting device located on at least one axle of the automotive vehicle. A fluid separator provided in the level regulator includes a hydraulic cylinder having at least one inlet pressure chamber confined by a hydraulic piston and separated from at least one outlet pressure chamber capable of being connected to the level adjusting device. Pressure is applied to the hydraulic piston by a restoring force acting in opposition to the pressure in the inlet pressure chamber. The inlet pressure chamber, through switch valves is capable of being temporarily connected to a primary hydraulic pressure source such as that for the brake system of the vehicle and, normally, is capable of being connected to a hydraulic fluid return reservoir. The fluid separator includes an input cylindrical housing in which is disposed a first piston portion closing the inlet pressure chamber.

Abstract: Disclosed is a suspension control apparatus for a vehicle having a plurality of suspension units each disposed between a road wheel and the body of a vehicle for effectively and quickly correcting any deviation of the vehicle height from a normal height level immediately upon finishing of active suspension control operations. Priority is determined for vehicle-height control and various active suspension control operations such as roll control, nose-dive and squat control, and pitching and bouncing control so that normal vehicle-height control is stopped or inhibited during active suspension control operations are being carried out, thereby preventing the traveling attitude of the vehicle from being made unstable.

Abstract: Underneath a load, on both sides, there are several transporter frames with transporter blocks for wheels. The wheels travel on tracks or rails, on which they are guided with wheel flanges or guide rollers. Each transporter frame has a vertical, U-shaped transporter frame foot, with a pivot shaft for the transporter block, which on the side opposite the pivot shaft has a support plate for the rounded head of a piston of a hydraulic cylinder. Each hydraulic cylinder is supported with its rounded head in a support bearing under the transporter frame. All the hydraulic cylinders of a series are connected by a connecting line and a check valve with a pump.

Abstract: A vehicular height control system detects lock condition of a drive wheel and a power train. When the lock condition of the drive wheel and the power train is detected, magnitude of the height adjustment is limited within a predetermined magnitude which corresponds to magnitude of rotation of the drive wheel allowed by play in the power train. By adjusting the vehicular height within a limited range, height difference between the predetermined height range and the actual vehicular height can be reduced. On the other hand, by limiting magnitude of height adjustment in the drive wheel and the power train clocked condition, overshooting in the height adjustment can be successfully prevented.

Abstract: In a traveling service unit of the type utilized in conjunction with a textile spinning mill machine, the transverse and longitudinal inclination of the service unit with respect to the machine is monitored and adjusted with respect to a fixed horizontal reference plane by at least two electronic levels or like inclination detectors each operatively connected through an associated controller with a vertically-adjustable roller wheel supporting assembly of the service unit for controlling the elevation of the service unit at each supporting assembly to compensate for detected inclination deviations.

Abstract: A mounting structure of a vehicle height sensor employs a reference height indicative marking put on a sensor body to be rigidly fixed onto a vehicle body, which marking represents a position of a movable sensor component corresponding to a predetermined vehicular height indicative signal level. On the other hand, a target height indicative marking is put on the vehicle body. Alignment of the vehicle height sensor can be adjusted with reference to the reference height indicative marking and the target height indicative marking. Alignment of the vehicle height sensor is achieved by aligning the reference height indicative marking to the target height indicative marking.

Abstract: A road-finishing machine provided with a level-compensation arrangement. A directional wheel installed on each side of a frame includes an axle to which a vertical pin is attached. The pin is slidably and rotatably accomodated with a cylinder housing having a hydraulic fluid-filled chamber therein into which the top of the pin, shaped like a piston head, is placed. Veertical motion of the wheel and corresponding motion of the pin cause hydraulic fluid to be expelled from or drawn into the chamber. The chambers of the wheels on opposite sides of the frame are in communication with each other. Consequently, as one wheel rises, the other is forced downward by the compensating hydraulic fluid, and vice-versa, to attain a level compensation effect.

Abstract: A four track vehicle especially adapted for logging on steep slopes includes a running unit and an upper unit. The upper unit is articulated relative to the lower unit to maintain a center of gravity within the four tracked pods upon which the running unit is mounted. Sensing systems are utilized to alert the operator when the machine is in an incipient tipping condition. Moreover, a unique suspension system combining a torsion frame and swingable pod mounting arms are employed. The pods are locked in position when the vehicle is in an operating mode and are unlocked when the vehicle is in a travel mode.

Abstract: A control system for governing multiple operating mode adjustable suspension units in an automotive vehicle with an adjustment mechanism for receiving an adjustment control signal for placing the suspension units in any of the multiple adjustment modes, and a fault warning mechanism for detecting an inability of the adjustment mechanism to adjust one or more of the suspension units and for generating a fault warning signal in response to such detection.

Abstract: A vehicle height control system wherein vehicle height control is inhibited when the vehicle is turning and in a rolling state, the state when the control is inhibited being based upon the vehicle's speed from a speed sensor, the steering angular velocity of a steering wheel from a steering angle sensor and the outputs from sensors detecting the height of the vehicle body on both sides of the vehicle with respect to the wheels, which by the pattern of their outputs, represent that the vehicle is inclined from side-to-side and in the rolling state.

Abstract: An actively controlled suspension system includes a vehicle rolling responsive component to adjust the suspension characteristics for suppressing vehicular rolling. In addition, the actively controlled suspension control system may be provided for adjusting roll-stabilization load distribution between the front and rear suspension systems for adjusting vehicular cornering characteristics.

Abstract: A four track vehicle especially adapted for logging on steep slopes includes a running unit and an upper unit. The upper unit is articulated relative to the lower unit to maintain a center of gravity within the four tracked pods upon which the running unit is mounted. Sensing systems are utilized to alert the operator when the machine is in an anticipitated tipping condition. Moreover, a unique suspension system combining a torsion frame and swingable pod mounting arms are employed. The pods are locked in position when the vehicle is in an operating mode and are unlocked when the vehicle is in a travel mode.

Abstract: This controller controls a varible damping force shock absorber taking the cycle time and the oscillating phase of the body vibration. The controller increases the damping force when the body is moving toward its mean position. Before that, the damping force is kept weak so that the body vibration is hastened to become moving toward the mean position. Some criteria for determining that the body is moving toward its mean position are proposed.

Abstract: In the forward undercarriage of a self-propelled hillside combine, all components for support and control of the transverse equalizing or balance beam, are below the floor level of a forward portion of the combine's separator body. In a compact structure which maintains good access to the separator concave and stone trap, and also to the hydraulic cylinders used to control the balance beam, the leveling cylinders diverge widely from a center pivot assembly so as to provide smooth action in control of the balance beam and also to minimize bending moments in the balance beam.

Abstract: In combination for use in a vehicle having a front, a back and sides to level the vehicle relative to gravity. A plurality of devices each disposed at an individual position relative to the vehicle and in displaced relationship to the other devices for adjusting the vertical position of the vehicle relative to gravity in accordance with the operation of pairs of adjacent devices. A sensor disposed relative to the vehicle for sensing the tilting of the vehicle from a level disposition relative to gravity. An operating structure responsive to the sensor for operating pairs of adjacent devices in a particular order to obtain an adjustment in the vertical position of the vehicle from side to side and front to back to obtain a resultant leveling of the vehicle relative to gravity.

Abstract: A system for automatically levelling a vehicle, such as a recreational vehicle, relative to gravity includes a plurality of extensible jacks, preferably hydraulic, disposed at strategic positions on the vehicle underside. Switches sense the downward tilting of the vehicle relative to gravity at the strategic positions and produce signals to operate the jacks in accordance with such tilting. Before the jacks are extended, air bags in the vehicle are deflated. When the hydraulic pressure in a hydraulic circuit exceeds a first value, the jacks are extended in a particular sequence depending upon the particular directions in which the vehicle is tilted relative to gravity. A delay is preferably provided between the operations of each jack and the next jack in the sequence to eliminate transients in the next jack operation. When the vehicle has been levelled, jacks not previously extended are extended until they engage the ground with a second pressure less than the first pressure.

Abstract: According to the present invention, as soon as the sporadic protrusion or sinking of a road surface is detected at the front wheel of the vehicle during its running on the road surface, the air chambers of the air suspensions for the right and the left rear wheels of the vehicle are connected to each other to alter the spring constant of the rear suspensions to `soft` when the rear wheel passes over the sporadic protrusion or sinking of the road surface, so that the feel of ride of the vehicle and the controllability and stability thereof are kept good. After the rear wheel moves over the sporadic protrusion or sinking, the characteristic of the rear suspensions is returned to the original state appropriate to the normal running state of the vehicle. Detectors for the sporadic protrusion or sinking of the road surface may be provided for the right and the left front wheels of the vehicle, respectively. The rear suspensions of the vehicle can be more appropriately controlled by that.

Abstract: A fork lift truck includes a mast support bar to which the mast supporting carriage and fork lift tines are mounted. The mast support bar includes a central arc-shape segment on which a concentric arc-shape mast support sleeve is slidably mounted. The mast is mounted to the sleeve and power means are provided to slide the sleeve in either direction on the mast support bar. When the fork lift truck encounters uneven ground so that the wheels on one side of the truck are higher than the wheels on the other, the operator will slide the mast support sleeve with respect to the mast support bar to keep the mast in a vertical position over the truck.

Abstract: A mower vehicle includes a vehicle frame and single front and rear driven wheels. The vehicle is adapted to conform generally to slopes and the like by maintaining the frame in a generally upright orientation. First and second blade housings are pivotally connected to the frame and swingable about an axis extending longitudinally of the frame. The first and second blade housings extend laterally from opposite sides of the frame. Each blade housing carries a driven cutting blade. The blade housings are open to one another and have a shared discharge passage at a center rear section thereof. The blades overlap slightly and rotate in synchronized reverse rotations relative to one another. Hydraulic cylinder assemblies are provided to actuate the first and second blade housings about the longitudinal axis in response to changes in slope of the surrounding terrain.

Abstract: Apparatus for leveling the front axle of an agricultural combine includes left and right wheel linkages in the form of four-bar linkages. A connecting rod synchronizes the motion of the four-bar linkages. Hydraulic cylinders are connected between the vehicle frame and the wheel linkages respectively to actuate the linkages such that as one wheel is raise above the axle the other wheel is lowered beneath the axle substantially the same amount as the first wheel is raised thereby maintaining the axle in a generally horizontal disposition.

Abstract: The vehicle height control apparatus according to the present invention comprises, vehicle height detecting unit (M3) provided at an appropriate position of a vehicle (M1) for detecting the distance between a body (M2) of the vehicle (M1) and the surface of road; vehicle height adjusting members (M5) provided between the body (M2) of the vehicle (M1) and wheels (M4) of the vehicle (M1) for adjusting the height of the a vehicle (M1); vehicle height control unit (M6) for obtaining controlled variable of the vehicle height adjusting members (M5) so that the actual vehicle height detected by the vehicle height detecting unit (M3) equals the predetermined target height and for driving the vehicle height adjusting members (M5), the vehicle height control unit (M6) being formed as an integral-added optimal regulator which determines the controlled variable of the vehicle height adjusting members (M5) on the basis of an optimal feedback gain predetermined in accordance with dynamic model of the system relating to the

Abstract: The present invention relates to mobile land vehicles having a boom assembly, and more particularly to vehicles used for felling and handling trees on steep mountainous terrain. The vehicle of this invention includes apparatus for providing multi-directional relative movement between a conventional tread assembly of the caterpillar type and a swing-house assembly which includes a boom subassembly supporting tree-felling and handling equipment, so that the swing-house assembly is maintained in a substantially level relationship with the horizontal, regardless of the inclination of the ground on which the vehicle rides, and so that the center of gravity of the vehicle is optimized by weight transfer corresponding to the type of ground inclination encountered.

Abstract: A suspension controller for controlling the suspension characteristic of a vehicle having a suspension which supports a vehicle body on plural wheels, wherein the distance between the vehicle body and at least one of the wheels is measured and a corresponding signal indicating the height of the vehicle is produced. This height signal is compared against preset reference signals and the characteristic of the suspension is altered, e.g., the suspension is made harder or softer, in dependance on the comparison. Additionally, the preset reference signals themselves are changed depending upon the alteration in the characteristic of the suspension. Changing the reference signals eliminates influence of the change in the amplitude of vibration of the height of the vehicle as a result of altering of the suspension characterisitc, whereby exact detection of a change in the amplitude of the vibration due to irregularities of the road surface is enabled to prevent overcontrol and hunting.

Abstract: An improvement in a working vehicle, such as a tractor, which includes a first frame part to which a steering wheel axle is coupled and a second frame part to which a second wheel axle is coupled with the frame part being pivotally interconnected to allow steering of the vehicle and wherein one of the wheel axles is swivelly mounted to its respective frame part to rock about a substantially horizontal axis so that one end of the rocking wheel axle is elevated when the vehicle is driven over uneven terrain.

Abstract: An elevating system for a vehicle load bed including a vehicle suspension system incorporating a .Iadd.suspension .Iaddend.support assembly pivotally mounted at one end to the load bed and releasably mounted at the second end .Iadd.thereof.Iaddend.. Selective release of the .[.secured.]. .Iadd.second .Iaddend.end allows pivotal separation of the load bed and suspension system .[.and.]. .Iadd.resulting in .Iaddend.a corresponding elevation of the load bed. Jacks interposed between the load bed and the suspension system control the pivotal separation. .Iadd.The elevating system is adapted to be installed on a conventional vehicle load bed and suspension system either during assembly of the vehicle or as an after market addition. .Iaddend.

Abstract: Present invention relates to an apparatus to improve the riding feel of the vehicle when the rear wheels pass over a sporadic hollows or protrusions of a ground by altering the rear suspension characteristic, i.e. the spring constant and the damping force of the shock absorbers after such hollows or protrusions are detected by front wheels of the vehicle passing thereover and the detected hollow or protrusion is judged to exceed a predetermined size. Besides that, the present invention has another control measures to give a priority to the maintenance of the vehicle posture when the driving condition is that need drivability and stability more than the riding comfort over the above-mentioned rear suspension characteristic alteration.