Abstract: A lift axle suspension system to be mounted under a vehicle for selectively raising a tire wheel assembly out of engagement with a road surface which vehicle includes a lift axle mounted to a hanger bracket via a pivot connector. The hanger bracket is rigidly attached to a vehicle frame and has articulating arms pivotally connected thereto. These arms connect at their opposite ends to the axle. A pair of diaphragm chambers such as brake chambers each include upper and lower chambers separated by a flexible bladder that moves under pressurization causing a push rod affixed thereto to translate. The diaphragm chambers and push rods extending therefrom are connected in different embodiments to the hanger bracket or other rigid structures as well as the articulating arm such that movement of the push rods causes movement of the articulating arms and thus movement such as lifting of the axle.

Abstract: Vehicle suspension device, specifically applicable to vehicles provided with rolling arrangements that has a resistance to the roll, pitch vertical rebound and axle crossing such that allows a weight distribution on every rolling arrangement, being such rolling arrangements connected all to a central device that is attached to the vehicle body, and that includes elastic means that through transmission means related to each other, receive the movements or forces originated in each wheel because of the weight variations and dynamic forces created on the vehicle during its traveling.

Abstract: An actuator assembly for moving an air valve between a position in which air is admitted to an air bag mounted in a vehicle and another position in which air is released from the air bag. The actuator assembly has a U-shaped rail that is attached to a cross member of the vehicle. The rail has a channel. A linear actuator is attached to the rail. The actuator has a moveable shaft. An actuator arm is attached to the rail and has a first end attached to the actuator. The actuator operates to linearly move the arm. A ball bearing is movably retained within the channel. The ball bearing has a stud extending from the ball bearing through the actuator arm and is attached to the actuator shaft. A mounting plate has an end attached to the air valve and another end attached to a second end of the actuator arm. The actuator operates to move the air valve so as to adjust the ride firmness of the vehicle.

Abstract: An accumulator is provided for a vehicle air system including a vehicle frame. A wheel end is spaced from the frame for supporting the vehicle frame on a roadway. A suspension assembly includes a suspension structure. The suspension structure may be a portion of an axle, a stabilizer bar, a control arm, or other suspension components. The suspension structure is interposed between the frame and the wheel end and is movable relative to the vehicle frame in response to the wheel end receiving inputs from the roadway. A fluid chamber forms the accumulator and is defined by a portion of the suspension structure for storing pressurized air. Preferably a valve is disposed within the fluid chamber to protect the valve from the environment. For light vehicle applications where a conventional air pump may be cost prohibitive, a mechanical pump may be connected between the vehicle frame and the suspension assembly.

Abstract: A pneumatic spring system is provided for a motor vehicle with a compressor unit, a storage unit, as well as on-off valves, via which the individual pneumatic springs of the individual wheels are supplied with compressed air. In the area between the compressor unit and the on-off valves, there is provided a vent line that empties out into the atmosphere and that can be locked or cleared by a locking valve. Provision is also made for measures with whose help the air mass flow, emerging via the cleared vent line during a certain time interval, can be limited with respect to an unlimited state in order to prevent any undesirable noise generation during the venting of the system. One measure connects in parallel to a separately lockable main vent line, a separately lockable high-pressure vent line whose clear through flow cross section is smaller than that of the main vent line. Alternatively, a choke element can be provided in the vent line.

Abstract: A closed level control system includes an air dryer (10) which is mounted in a pressurized air line (4). The compressor output (16) can be connected to the pressurized air supply vessel (12) via the pressurized air line (4). Air from the atmosphere can be transferred via an intake valve (30) into the pressurized air supply vessel (12) via the compressor and the air dryer (10). Furthermore, pressurized air can be discharged into the atmosphere from the pressurized air supply vessel (12) via the air dryer (10) and the intake valve (30). There is a flow in the opposite direction through the air dryer than when filling the pressurized air supply vessel (12) from the atmosphere. In this way, an excellent regeneration of the air dryer (10) is ensured.

Abstract: An automatic air suspension control system for a tractor trailer includes a system for allowing suspension air pressure to be dumped for the suspension system during a necessary and required loading/unloading of the tractor trailer. The control system includes a transmission device and an receiving device for activating a valve for exhausting the air pressure from a suspension unit.

Abstract: The invention relates to a closed level control system for a vehicle. The closed level control system includes a pump which transfers a pressurized medium between a pressurized medium supply vessel (4) and pressurized medium chambers (2a to 2d). The input (8) of the pump (6) is connected to the supply vessel (4) and the output (10) of the pump (6) is connected to the pressurized medium chambers (2a to 2d) when the pressurized medium is to be pumped from the supply vessel (4) into the pressurized medium chambers (2a to 2d). If, in contrast, pressurized air is to be pumped from a pressurized medium chamber (2a to 2d) into the supply vessel (4), then the input (8) of the pump (6) is connected to the pressurized medium chamber and the output (10) of the pump (6) is connected to the supply vessel (4). The above-mentioned connections preferably take place via controllable directional valves (14, 18). The level control system makes it possible that the pump (6) has to always run only in one direction.

Abstract: A suspension system that restricts side-to-side airflow between air springs on opposite sides of a vehicle or trailer. In one embodiment, active airflow discs in suspension ports of a valve operate in two modes; restrictive and non-restrictive. A disc attains a non-restrictive mode when air is exhausted from an air spring. A disc attains a restrictive mode when air is injected into the suspension port from the valve toward an air spring. Airflow discs in opposing suspension ports both attain a non-restrictive state to rapidly dump air from the springs and lower vehicle ride height. In another embodiment, a pneumatic circuit includes one-way check valves, in fluid communication with opposing air springs, aligned to restrict airflow between the opposing springs under uneven loading conditions. A pair of electronic solenoids acts in concert with the check valves to selectively inflate or deflate the air springs.

Abstract: A suspension hanger assembly for receiving the bush end of a control arm is provided for adjusting axle alignment, without vertical displacement, and includes spaced-apart sides; each having aligned bores for a spindle, a bush pin and a fastening bolt. Two cams, having openings for the spindle, bush pin and fastening bolt, are aligned with the bracket bores. The bush pin bore of the bracket is horizontally elongated limiting vertical displacement of the bush pin. The fastening bolt opening of each cam is arcuate-shaped which allows cam actuation in an eccentric pattern. As the cam is moved, the bush pin moves horizontally respective to the bracket. The control arm bush is secured via the bush pin and fastening bolt. The control arm is fixed to the axle and horizontal movement of the control arm within the hanger bracket results in linear movement of that axle respective to the vehicle chassis.

Abstract: A control system is designed to lift and lower the body of an air-suspended vehicle including an axle and level control.

Abstract: Valve arrangement for multi-axle vehicles having air suspension, which vehicle is provided with at least one axle (1, 2, 3) having two or more air suspension elements (4,5, 6,7, 8, 9, 30) which can be pressurized by means of a source of compressed air (10), valves (13,14,15,16,17,18) for pressurizing or venting said air suspension elements, and a control unit (25) for controlling opening and closing of said valves. A valve unit can also be provided for each air suspension element, which valve unit comprises a first valve (15a, 16a, 44) between the source of compressed air (10) and the air suspension element (4, 5,6,7,8, 9, 30), for pressurizing said air suspension element, and a second valve (15b, 16b, 49) connected between the first valve and the air suspension element, for venting said air suspension element, which valves are normally closed. The invention further relates to a valve unit for said valve arrangement and a vehicle provided with such a valve arrangement.

Abstract: A suspension assembly for a vehicle is provided that includes a frame supporting upper and lower control arms in spaced relation to one another that are pivotally connected to the frame. A steering knuckle is supported between the control arms and supports a wheel. The orientation of the knuckle defines the wheel attitude, which includes caster, camber, toe, and track. The knuckle is rotated about its axis in response to mechanical inputs from a steering wheel. First and second actuators may be supported on one of the control arms and connected to a portion of the knuckle. A third actuator may be supported on the other control arm and connected to another portion of the knuckle. At least one sensor detects vehicle ride conditions such as braking, vehicle yaw, and steering position. A controller is connected to the sensors and the actuators to command the actuators to adjust at least one of the caster, camber, toe, and track in response to the vehicle ride conditions.

Abstract: A vehicle suspension has one or more hydraulic cylinders connecting an axle to a frame of the vehicle and each cylinder has a first and second chambers. The suspension operates in either a regeneration mode, in which a fluid path is provided between the first and second chambers, and a double acting mode, in which the first and second chambers are isolated from each other and fluid flows between each chamber and a separate accumulator. The selection between the regeneration and double acting modes is made in response to the pressure level in the cylinder as determined by a pressure sensor of a closed loop control system or by the pressure versus current characteristics of a electrically operated valve in the suspension for a loop control system. The hydraulic system also is able to raise and lower the suspension as necessary due to changes in the load carried by the vehicle.

Abstract: A suspension for a heavy duty vehicle is provided that includes a frame. A lower linkage is supported by the frame at a first pivotal connection. A drive axle assembly is supported by a lower linkage at a second pivotal connection. The drive axle assembly includes an input shaft defining a pinion angle. An upper linkage interconnects the drive axle assembly and the frame at third and fourth pivotal connections, respectively. The upper linkage includes an adjustment member, such as a turnbuckle, for modifying the length of the upper linkage to obtain a predetermined pinion angle. In this manner, the pinion angle may be adjusted upon assembly of the suspension system. Furthermore, by permitting the drive axle assembly to pivotally move relative to the linkages, the pinion angle may be maintained during suspension movement.

Abstract: A lift axle control system is provided for a vehicle that has fixed axles and a lift axle. The lift axle is configured to move between a raised position spaced apart from the ground and a lowered position in contact with the ground to reduce the load carried by the fixed axles. The lift axle control system is configured to control the raising and lowering of the lift axle. According to a preferred embodiment of the disclosure, the lift axle control system includes a housing and a valve configured to control the flow of air to a lower bag that lowers the lift axle into contact with the ground.

Abstract: A vehicle roll control system comprises a torsion bar and a first arm extending-substantially perpendicular to the torsion bar. The first arm is fixed to the torsion bar at one end and connectable to one of the axles at the other end. A hydraulic actuator is attached to the torsion bar; and a control connected to the hydraulic actuator controls the operation thereof on detection of a predetermined vehicle condition. The hydraulic actuator comprises a housing, a piston making a sealing sliding fit inside the housing to define a first fluid chamber and a second fluid chamber, and a piston rod connected to the piston and extending through the second fluid chamber and out of the housing.

Abstract: A hydraulic suspension strut (30) has a first on-off valve (58) connecting the first and second chambers (42 and 44), and a second on-off valve (62) connected to chamber (42) only. Suspension arm (3) of wheel (1) can be retracted beyond normal road travel, or protracted to road travel mode, by use of pump (9) and valves (58 and 62). The space in the strut above port (56) may be used as a hydraulic bump stop. An accumulator (50) may be included, as a hydraulic spring. Alternatively, strut (70) (FIG. 6; note alternative accumulator position) allows suspension to be raised above normal road travel. Strut (100) (FIG. 8) may be operated in roadgoing raised, or retracted mode. These struts may be applied to reconfigurable suspensions; particularly for amphibious vehicles, which may require wheels to be withdrawn above the hull water line to reduce drag on water, particularly during cornering.

Abstract: An actuator assembly for moving an air valve between a position in which air is admitted to an air bag mounted in a vehicle and another position in which air is released from the air bag. The actuator assembly has a U-shaped rail that is attached to a cross member of the vehicle. The rail has a channel. A linear actuator is attached to the rail. The actuator has a moveable shaft. An actuator arm is attached to the rail and has a first end attached to the actuator. The actuator operates to linearly move the arm. A ball bearing is movably retained within the channel. The ball bearing has a stud extending from the ball bearing through the actuator arm and is attached to the actuator shaft. A mounting plate has an end attached to the air valve and another end attached to a second end of the actuator arm. The actuator operates to move the air valve so as to adjust the ride firmness of the vehicle.

Abstract: A system and method for improving the traction of a vehicle uses weight distribution control to improve wheel to driving surface friction. A driven axle and a non-driven axle support a vehicle load through adjustable suspension members. The suspension members are, for example, air bags. Actuators and controllers adjust the suspension members in a selectable predetermined manner. The selection can be based on operator preference, vehicle operating mode, or a sensed loss of traction. The driven axle carries a drive axle maximum rated load in order to maximize drive wheel traction at all times.

Abstract: The invention is directed to a method of filling a pressurized medium chamber of a level control system which includes a pressurized medium store and a compressor. The pressurized medium chamber is filled from the pressurized medium store over a time span during which the pressurized medium difference between the pressurized medium store and the pressurized medium chamber exceeds a threshold value. When the pressurized medium difference between the pressurized medium store and the pressurized medium chamber reaches the threshold value, a further filling of the pressurized medium chamber is necessary and takes place by means of the compressor of the level control system.

Abstract: An air spring system for a two axle motor vehicle has a compressed air source and control valves. The control valves are assigned to the individual motor vehicle wheels and by means of which the respective vehicle wheel air springs can be connected by choice to a compressed air supply line which is connected to the compressed air source. The air springs of the vehicle front axle and the air springs of the vehicle rear axle have their own compressed air line branches, whose cross sections differ at least by segments; and the line branch of one of the two axles is designed in such a manner that its flow cross section during compressed air infeed into the assigned air springs differs at least by segments from the flow cross section during compressed air bleeding from the assigned air springs.

Abstract: A suspension system for a vehicle having left and right wheels is disclosed and claimed. The system includes first and second suspension struts and first and second hydraulic cavities to supply first and second suspending spring force for the left and right wheels, respectively. The system also includes a volume modulator to selectively push fluid into and vent fluid from the first and second hydraulic cavities, thereby actively modulating the first and second suspending spring forces. The volume modulator includes first and second modulator pistons and first and second cavity-side valves. In a preferred embodiment, the modulator pistons are cycled and the cavity-side valves are opened and closed to counteract roll of the vehicle. Further, in a preferred embodiment, the first modulator piston and the second modulator piston are located approximately 180° apart relative to an eccentric to minimize power consumption of the volume modulator during roll of the vehicle.

Abstract: Suspension system for a vehicle is disclosed and claimed. The suspension system includes a fluid, a suspension strut, a hydraulic cavity, an accumulator, and a volume modulator. The hydraulic cavity is at least partially defined by the suspension strut and is adapted to contain a portion of the fluid. The hydraulic cavity supplies a suspending spring force that biases a wheel of a vehicle toward the road surface. The volume modulator selectively pushes the compressible fluid into the hydraulic cavity and vents the compressible fluid from the hydraulic cavity, thereby actively modulating the suspending spring force.

Abstract: A suspension system that restricts side-to-side airflow between air springs on opposite sides of a vehicle or trailer. In one embodiment, active airflow discs in suspension ports of a valve operate in two modes; restrictive and non-restrictive. A disc attains a non-restrictive mode when air is exhausted from an air spring. A disc attains a restrictive mode when air is injected into the suspension port from the valve toward an air spring. Airflow discs in opposing suspension ports both attain a non-restrictive state to rapidly dump air from the springs and lower vehicle ride height. In another embodiment, a pneumatic circuit includes one-way check valves, in fluid communication with opposing air springs, aligned to restrict airflow between the opposing springs under uneven loading conditions. A pair of electronic solenoids acts in concert with the check valves to selectively inflate or deflate the air springs.

Abstract: The invention relates to a pneumatic system for a motor vehicle, said pneumatic system comprising a compressor unit, an accumulator unit and switch valves, via which the individual springs of the individual vehicle wheels are provided with pressurized air. A vent line is provided in the zone between the compressor unit and the switch valves. Said vent line opens into the atmosphere and can be blocked or released by a stop valve. The inventive system is further provided with devices that are used to limit the air mass flow discharged via the released vent line in certain intervals vis-à-vis an unlimited state in order to prevent undesired noises caused by the venting of the system. For example, a separately blockable high-pressure vent line can be connected parallel to a separately blockable main vent line, the free effective area of flow of the high-pressure vent line being smaller than that of the main vent line.

Abstract: Improved adjustable shock absorbers comprising a cylinder, a piston movable within said cylinder, a source of hydraulic or pneumatic fluid, a pump, means connecting said source to supply fluid through said pump to said cylinder, valve means operable from the driver's seat for regulating the flow of fluid from said source to said cylinder, damper means located within said cylinder for controlling oscillation of said piston, said cylinder and piston being connected between the axle and frame of said vehicle to regulate the ground clearance and ride stiffness of said vehicle.

Abstract: A vehicle suspension control system that allows substantially vertical motion of each wheel relative to the vehicle body includes front and rear resilient support means for supporting the body, a front roll stabilization assembly interconnecting at least one forward pair of wheels and a rear roll stabilization assembly interconnecting at least one rearward pair of wheels. Each roll stabilization assembly includes at least one lateral torsion bar (2) and a double-acting hydraulic actuator (3) interconnected to the at least one lateral torsion bar (2), the front and rear hydraulic actuators (3) being interconnected by first and second fluid conduits (5). Roll moments applied to the vehicle body generate pressure within the fluid conduits (5) thereby transmitting the roll moment into each lateral torsion bar (2).

Abstract: A height control valve is preferably adapted to be mounted in a trailing arm suspension and fluidly interconnected to a source of pressurized air and to an air spring. The height control valve comprises a housing having a cylindrical bore, a supply port, an exhaust port and an air spring port each of which extends through the housing and fluidly communicates with the bore. A rotor is preferably rotatably mounted in the bore and interconnected to the arm wherein pivotal movement of the arm rotates the rotor with respect to the housing between first, second and third rotational positions.

Abstract: Disclosed is a suspension system for equalizing the load on a vehicle, preferably a farm wagon. The system comprises four double acting hydraulic cylinders at each of the four corners of a farm wagon which are plumbed in a closed loop circuit. Fluid displaces between the four cylinders during use in order to maintain equilibrium within the system. The displacing fluid results in movement of each respective corner and wheel with respect to the ground.

Abstract: A trailing arm suspension, alone or in combination with a vehicle having a vehicle frame supported by an axle with ground engaging wheels. The trailing arm suspension comprises a pair of spaced trailing arm assemblies, each of which includes a trailing arm pivotally mounted to a the vehicle frame and a spring operably coupling the trailing arm to the frame to resist the pivotal movement of the trailing arm. A pneumatic lift mechanism is provided to selectively raise the trailing arm relative to the frame. The axle has at least a portion of which that is hollow and defines a pressurized air reservoir, which is coupled to the spring and/or the pneumatic lift mechanism to provided pressurized air for altering the resistance of the spring and/or actuating the pneumatic lift mechanism to selective lift the trailing arm.

Abstract: A vehicle suspension system includes a hydraulic anti-roll mechanism in which a pair of suspension arms (10a, 10b), on opposite sides of the vehicle, are mounted to the vehicle body pivots (16a, 16b). A pair of hydraulic struts (22a, 22b) are connected between the suspension arms and the body (14). The struts are asymmetrically mounted so that one is inboard of its suspension arm pivot and the other is outboard of its suspension arm pivot. The two lower chambers of the struts (22a, 22b), through which the connecting rods (32) of the pistons extend, are hydraulically interconnected, and so are the two upper chambers.

Abstract: A device for controlling the flow rate of hydraulic fluid in a supply line for the cylinder chambers of suspension cylinders in vehicles, especially tractors, having a permanent suspension axle, whose height is regulated by a level control device, a choke being inserted into the supply line for limiting the flow rate of the hydraulic fluid, the supply line (2) being furnished with a bypass line (15) circumventing the choke (4), an auxiliary choke (16), controlled by a control unit (17) having level sensors, being inserted into the bypass line, the auxiliary choke being switched on in response to pronounced static load change when the limit stops of the vehicle axle are reached, permitting a larger flow rate of the hydraulic fluid.

Abstract: A towed implement is provided with ground support wheels mounted to its chassis by trailing wheel support arms and respective suspensions including lift cylinders with which are associated damping devices that operate in such a way as to prevent damage to a respective cylinder from rebounding forces resulting when the suspension is being returned to its operating position by the release of energy stored in spring arrangements of the suspension after being loaded by an obstacle engaging the associated wheel. In one embodiment, the spring arrangement includes a damping spring located between an end of the associated cylinder and piston, and in another embodiment, the spring arrangement includes a gas pressure reservoir which, by virtue the operation of a reversing link in the suspension, is loaded both when the wheel is caused to move in a first direction by engaging an obstacle, and when the wheel is moved in the opposite direction by the airborne wheel once past the obstacle.

Abstract: An adjustable vibration damper, having a displacer in a cylinder, a damping medium exerting a damping force via an adjustable damping valve. The adjustable damping valve is activated by a control pressure of a pneumatic spring A safety device is provided which, in the event of a control pressure reduced as a result of damage to the pneumatic spring, provides a sufficiently high damping force of the vibration damper. At least two pneumatic springs are connected to the safety device, which is constructed from a pneumatic circuit functioning as a pressure balance between the pneumatic springs which releases the higher control pressure of a pneumatic spring in the pneumatic circuit. The adjustable vibration dampers which belong to the pneumatic springs are connected via at least one pressure outlet connection of the pneumatic circuit and are activated by the highest control pressure of the pneumatic springs involved.

Abstract: The invention relates to a level control arrangement for vehicles having air springs (6a) to (6d) and a pneumatically controllable directional valve (26). A residual pressure holding function and an overpressure function are integrated into the directional valve (26). The directional valve (26) is controlled by the air pressure in the air springs (6a) to (6d). The air pressure can be applied via a control line (20) to a control input (24) of the directional valve (26). The air from the air springs (6a) to (6d) is released with the aid of the venting line (28). The venting line (28) is guided separately from the control line (20) through the directional valve (26). In this way, a large air flow can be conducted through the venting line (28) without the static air pressure in the control space (50) of the directional valve (26) being reduced. The venting line is blocked by a stepped piston (44) of the directional valve when no air is to be released from the air springs.

Abstract: Level adjustment device for vehicles with air springs 8a through 8d, by which a vehicle body is furnished with suspension on at least one vehicle axle, which includes the following: a source of compressed air 2, which, for the purpose of filling air springs 8a through 8d, can be connected to air springs 8a through 8d via an air dryer 4, the air dryer 4, for the purpose of filling the air springs, is connected on one side to air springs 8a through 8d through a check valve 6 that is open to air springs 8a through 8d, each air spring 8a through 8d, for the purpose of emptying them, can be connected through the air dryer 4 and through a pneumatically controlled first distribution valve 10 to the atmosphere, wherein the pneumatic control input 38 of this distribution valve 10 is then impinged through a second controllable distribution valve 12 with the pressure in air springs 8a through 8d against a restoring force 50 acting on the pneumatic control input 38, the pneumatic control input 38 of the pneumatically co

Abstract: An air-suspension system has at least one air spring arranged between a chassis and a vehicle component mounted relative to said chassis for movement along an oscillatory path. A control valve is arranged inside the air spring and has control positions for feeding, blocking and discharging compressed air in the air spring. The control valve is activated via a control element also arranged inside the air spring. A guideway of the control element acts on one of an outer tube air-spring subassembly and a rolling tube air-spring subassembly which are movable relative to one another. The control valve is designed as a rotary-slide valve and is activated via the guideway and a rotary-slide valve body. The guideway of the control element is shorter than the stroke length of the air spring, the one of the subassemblies which actuates the control element being in releasable operative connection with the control element.

Abstract: A suspension system with an oscillating, rigid axle, particularly for tractors, is described; the axle is supported on a sub-frame with oscillating arms which in turn can be mounted for oscillating on a load-bearing structure of the tractor by suspension means interposed between the axle and the load-bearing structure, the sub-frame comprising at least two pairs of arms arranged so as to form a so-called pantograph-like kinematic linkage.

Abstract: An emergency brake backup system is achieved by selectively interconnecting the air suspension as an additional reservoir to the air brake system. That is, if the charging system or primary reservoir fails, compressed air in the air spring reservoirs is used as an energy source to supply the pressurized air required for brake function. This can be achieved with minor modification to existing tractor and trailer brake systems that employ air suspension assemblies.

Abstract: A levelling valve actuating apparatus is provided for converting a linear displacement resulting from a vehicular height change into a rotational displacement and controlling operation of a levelling valve, the apparatus positioned between a wheel-side suspension and the levelling valve, the valve being supplied with operating air from an air source and the air supply to an air spring adjusted by means of actuation of a rotary plate for intermittently interrupting a hydraulic fluid passage within the valve body, comprising a lever for adjusting vehicle height one end of which is connected to the rotating plate of the levelling valve outside of the valve body, a connecting slot being formed at an opposite end of the lever in a longitudinal direction, a rack being formed on the inside of the connecting slot along the longitudinal direction; a rod for adjusting vehicular height having an arcuate external shape, an end of the rod being mounted on a side of the suspension through a ball joint, an arcuate slot bein

Abstract: A proportional load transfer valve is disclosed to shift a predetermined ratio of approximately fifty percent (50%) of the weight on a tag axle to the drive axle. The load transfer valve acts in response to a pneumatic signal indicative of a traction event. The valve alters the ratio of supply port pressure associated with the air suspension bags of the drive axle that is forwarded to the delivery port associated with the air bag suspension assembly of the tag axle. As the weight imposed on the drive axle approaches a predetermined maximum, the load transfer valve transfers less weight so that the drive axle is not overloaded.

Abstract: An apparatus for controlling pivoting of a forklift rear axle. A hydraulic damper is arranged between a rear axle and a forklift body. The damper includes two oil chambers. The oil chambers are connected to a first passage and a second passage. A two-way switch valve is arranged between the oil chambers. The valve permits the flow of oil between the oil chambers and allows pivoting of the rear axle when opened. The valve restricts the flow of oil between the oil chambers and prohibits pivoting of the rear axle, thereby locking the rear axle when closed. When the rear axle is released from a locked state, the valve repeats a valve cycle, which includes opening and closing the valve, to regulate the amount of fluid that flows between the chambers. The valve is then kept in an opened state. This prevents shock that may be produced by sudden tilting of the body when the rear axle is released from a locked state.

Abstract: A suspension system for a vehicle tandem axle has air springs positioned adjacent the ends of the trailing and lead axles of the tandem axle. Pairs of air springs on each side of the vehicle are pneumatically connected to form a common reservoir. Displacement of the ends of the lead and trailing axles of the tandem axle are averaged to provide a controlling input to air spring pressurization controllers provided for each pair of air springs.

Abstract: A height control valve is preferably adapted to be mounted in a trailing arm suspension and fluidly interconnected to a source of pressurized air and to an air spring. The height control valve comprises a housing having a cylindrical bore, a supply port, an exhaust port and an air spring port each of which extends through the housing and fluidly communicates with the bore. A rotor is preferably rotatably mounted in the bore and interconnected to the arm wherein pivotal movement of the arm rotates the rotor with respect to the housing between first, second and third rotational positions.

Abstract: An anti-creep device for a trailer includes a support arm adapted to be mounted to a trailer frame proximate a trailer axle for rotational movement between a retracted position and an extended position. An actuator is associated with the support arm for rotating the arm at least to the extended position to thereby lock the frame at a selected height when the frame is raised with respect to the axle. A sensor switch is mounted to the frame in the vicinity of the support arm for sensing the position of the support arm and an indicator is operably connected to the sensor for indicating when the support arm is in the extended position.

Abstract: A number of embodiments of suspension systems for vehicles having at least two wheels, each of which is independently suspended by a system including a respective shock absorber. The shock absorbers may be generally conventional in nature but are interconnected by a system that includes an accumulator and a flow control so as to provide a damping for vehicle characteristics that is independent of the individual damping of each wheel's shock absorber. The systems also provide constructions so that both the vehicle and individual wheel damping can be independently controlled to permit the use of smaller shock absorbers.

Abstract: A vehicle comprising a body having a front end and a rear end, front wheels carried by a front axle mounted to the body proximate the front end of the vehicle, rear wheels carried by a rear axle mounted to the body proximate the rear end of the vehicle, a cargo body mounted to the body for carrying a load, a framework having an inner end pivotally mounted to the rear end of the vehicle and having an outer end, wheels mounted for rotation to a trailing axle, the trailing axle mounted to the outer end of the framework for transverse pivotal movement relative the cargo body, the trailing axle movable between an extended orientation wherein the trailing axle is located generally outboard of the outer end of the framework and a retracted orientation wherein the trailing axle is located generally inboard of the outer end of the framework, and a pair of lifting arms for moving the framework relative the cargo body of the vehicle from an operative position wherein the trailing axle is positionable in the extended ori

Abstract: A body leveling system for a motor vehicle including a rigid axle housing, a pair of dirigible wheels on the rigid axle housing, and a pair of air springs between the body and the rigid axle housing. During a turn, links between the body and the rigid axle housing effect roll understeer by turning the axle housing toward the center of the turn in response to pivotal movement of the body about its longitudinal roll axis. When the load on the vehicle body is in a moderate range from empty to four average passengers, the air springs are selectively inflated and deflated to maintain the body at curb trim. When the load on the body exceeds the moderate range in either a high range or an overload range, the air springs are sealed closed and incrementally vertically deflect as the load increases. The GVW trim of the vehicle body is below its curb trim and its center of gravity is lower at GVW than at curb trim for improved dynamic performance at GVW.

Abstract: A load distribution unit for a hydraulic vehicle suspension system has a pair of cylinders with each cylinder defined by a block which is common to the cylinders and four cylinder sleeves, two sleeves for each cylinder extending from opposite sides of the block. The sleeves are fixed to the block by an end cap for each sleeve, with fasteners extending from the end cap to the block to compress the associated sleeve between the end cap and the block and estalish a seal between the block and the sleeve and the end cap and the sleeve. The LDU is mounted to the vehicle with a three point mounting, and with the cylinder sleeve cantilevered from the block. A clam shell compartment is mounted and sealed to one of the end caps of each cylinder, which is covered so that its interior is accessible without breaking the seal of the clam shell compartment with the end cap.