Abstract: Lift frames for a vehicle in this disclosure may include a frame body on a top portion of a frame, the frame body extending from a first end to a second end; a lift mechanism moveable with respect to the first end of the frame body, the lift mechanism comprising: a lift body having a first end and a second end, a lifting surface on the first end of the lift body and the second end of the lift body being positioned so as to be movable with respect to the first end of the frame body, wherein the lifting surface is positioned to engage an underside of a cargo container when placed on an upper side of the frame body; and an inflatable air bag having an upper side and a lower side and mounted on the lower side to a platform positioned on the frame beneath the lift body, wherein the inflatable air bag is connected on the upper side thereof to a mounting surface attached to the lift body; and a source of compressed air in fluid communication with the inflatable air bag.

Abstract: Lift frames for a vehicle in this disclosure may include a frame body on a top portion of a frame, the frame body extending from a first end to a second end; a lift mechanism moveable with respect to the first end of the frame body, the lift mechanism comprising: a lift body having a first end and a second end, a lifting surface on the first end of the lift body and the second end of the lift body being positioned so as to be movable with respect to the first end of the frame body, wherein the lifting surface is positioned to engage an underside of a cargo container when placed on an upper side of the frame body; and an inflatable air bag having an upper side and a lower side and mounted on the lower side to a platform positioned on the frame beneath the lift body, wherein the inflatable air bag is connected on the upper side thereof to a mounting surface attached to the lift body; and a source of compressed air in fluid communication with the inflatable air bag.

Abstract: A method for attaching a rear frame suspension module to an existing vehicle that will operate on the existing automotive engine, heating, and cooling system. The rear frame suspension module supports passengers sitting straddled in a front to back position to give an existing vehicle a motorcycle-like appearance. The rear suspension module can be attached and removed from an existing automobile front frame suspension module. The resulting wider front structure of the vehicle makes for safer riding compared to a two wheel motorcycle. Vehicle maintenance can be done at most automotive repair shops.

Abstract: A method of manufacturing a vehicle frame body, the method includes: a placement process of placing a reinforcing member at a portion of a frame member, the portion being located in a length direction of the frame member and within the frame member, the frame member being a single member having an elongated shape and configuring a chamber structure; and, after the placement process, a bending process of bending the frame member at a placement region of the reinforcing member, causing reaction force to be generated by the reinforcing member against the frame member undergoing cross-sectional deformation, and pressure joining the reinforcing member to the frame member.

Abstract: A kingpin assembly comprises a housing having a recess located therein, a kingpin having at least a portion located within the recess of the housing, a coupler member operably coupled to the kingpin, and a collet member engaging the housing and the kingpin, and engaging the coupler member such that an uncoupling of the coupler member from the kingpin at least partially disengages the collet member from the kingpin.

Abstract: A kingpin assembly comprises a housing having a recess located therein, a kingpin having at least a portion located within the recess of the housing, a collar member operably coupled to the kingpin, and a collet member extending about the kingpin and frictionally engaging the housing and the kingpin.

Abstract: A bearing assembly having a bearing block of a fifth wheel coupling. The bearing block has at least one vertical fastening flange. The tractive unit has a frame element, which has a vertical section. The vertical fastening flange is connected to the outside of the vertical section by a screw connection. A component, on which the vertical fastening flange is supported at least in the vertical direction, is fastened to the vertical section.

Abstract: A trailer slider locking system includes body rails longitudinally slidable relative to a suspension frame side rail. The body rails have holes providing multiple suspension positions. A pin locking system includes a pin moveable between retracted and locked positions. An end of the pin is received in one of the holes in the locked position. The pins have tapered ends so that the pin will extend through the body rail hole prior to advancing to the fully locked position.

Abstract: A high-performance, light-duty, utility trailer that is pulled by a tow vehicle utilizing a two point coupling to the tow vehicle and a swiveling axle assembly. This novel design includes a tilting hitch assembly attached to the trailer frame and swiveling casters attached to the rear corners of the trailer frame, creating a three point “landing gear” for easy installation onto the tow vehicle and providing good un-hitched mobility allowing the trailer owner to easily move the trailer out-of-the-way when stored between each use. A wheel swiveling assembly that can be configured to provide steering geometry capable of being customized to accommodate driving habits and road conditions. A two point hitch assembly that allows the removal of adaptors when not in use for both functional and aesthetic purposes.

Abstract: Two fifth wheels of different throat diameters are mounted facing each other 180 degrees apart on a turntable member that can be rotated on an underlying support member. The underlying support member may be a permanent part on a towing or tractor vehicle, or a detachable part such as a fifth wheel support body. This enables a single towing vehicle to tow semitrailers having kingpins of different sizes without changing the kingpins.

Abstract: A portable sensor and indication system and method for sensing the position of a trailer body relative to an axle frame and providing an alert signal to an operator when the locking pins on the trailer body and the holes on the axle frame rails are aligned. Once the alert signal is provided, the locking pins may be engaged to lock the trailer body to the axle frame.

Abstract: A locking pin mechanism for a transport semi-trailer, the locking pin mechanism is used for locking longitudinally extending members of a frame of a transport semi-trailer together with a trailer body movably arranged on the longitudinally extending members. The locking pin mechanism comprises at least two bolt assemblies and a linkage assembly for driving the at least two bolt assemblies. The bolt assembly comprises a bolt, an inner spring, a sliding sleeve, an outer spring and a bracket. The sliding sleeve at an end away from its sliding sleeve end-plate is connected with the linkage assembly; the linkage assembly can be pulled such that the sliding sleeve of the bolt assembly is compresses the inner and outer springs to force the bolt to be pulled out from a locating hole under an action of an elastic force of the inner spring; and after the linkage assembly is released, the bolt can be inserted into the locating hole under the action of the elastic force of the outer spring.

Abstract: A trailer slider locking system includes body rails longitudinally slidable relative to a suspension frame side rail. The body rails have holes providing multiple suspension positions. A pin locking system includes a pin moveable between retracted and locked positions. An end of the pin is received in one of the holes in the locked position. The pin has a first centerline and the holes have a second centerline. The end of the pin extends through the hole with the centerlines being offset from one another in the locked position. The pins have tapered ends so that the pin will extend through the body rail hole prior to advancing to the fully locked position.

Abstract: A device for adjusting a fifth wheel, comprising a displacement device provided with two guide rails placed on the vehicle, in particular on a tractor semi-trailer combination in the longitudinal direction thereof, said guide rails whereon a slide may be installed capable of being moved by means of an actuating device, said actuating device being designed such that, upon a displacement, the positive connection between the guide rails and the slide is maintained. The actuating device, which is designed to move the slide, comprises a first powered device. Additionally, at least one first position sensor is arranged to detect the position of the slide, at least said first position sensor being connected to a control device.

Abstract: A system and method for determining whether a vehicle and its axles exceed predetermined roadway weight limitations. Air fittings are installed in the air-ride systems of the vehicle. Air pressure readings taken using a hand held gauge are compared to maximum pressure values marked on the vehicle. If the air pressure exceeds the values, weight may be redistributed, if possible, until measured pressure is equal to or less than the maximum pressure values. The method allows an operator to quickly confirm that the total weight and axle weight does not exceed legal limits without the use of truck scales.

Abstract: A device for adjusting a fifth wheel, comprising a displacement device provided with two guide rails placed on the vehicle, in particular on a tractor semi-trailer combination in the longitudinal direction thereof, said guide rails whereon a slide may be installed capable of being moved by means of an actuating device, said actuating device being designed such that, upon a displacement, the positive connection between the guide rails and the slide is maintained. The actuating device, which is designed to move the slide, comprises a first powered device. Additionally, at least one first position sensor is arranged to detect the position of the slide, at least said first position sensor being connected to a control device.

Abstract: A dual trailer has a first trailer with a king pin for a tractor and a rear fifth wheel for the king pin of a second trailer. The rear end of the first trailer and the front end of the second trailer is lifted into an empty transport position so that the first and second trailers are supported solely on the tractor and the rearmost axle of the second trailer. The remaining axles are held raised from the ground by the lifting of the trailers and by an individual lifting hook supporting the axle raised relative to the frame. In the empty transport position, the first and second trailers are maintained as a single integral trailer in a directly aligned position. Each axle includes an air bag so that the hook is engaged when the axle is raised relative to the frame by releasing the air from the bag.

Abstract: A fifth wheel assembly for coupling a trailer to a truck tractor is provided and includes a fifth wheel and a supporting structure for supporting the fifth wheel on the rear part of the tractor truck. The supporting structure includes a sliding arrangement enabling the fifth wheel to be repositioned between different positions. A number of sensors are positioned on the supporting structure and on the fifth wheel and are included in a control system for predetermined information and control of operating conditions.

Abstract: A trailer slider locking system includes body rails longitudinally slidable relative to a suspension frame side rail. The body rails have holes providing multiple suspension positions. A pin locking system includes a pin moveable between retracted and locked positions. An end of the pin is received in one of the holes in the locked position. The pin has a first centerline and the holes have a second centerline. The end of the pin extends through the hole with the centerlines being offset from one another in the locked position. The pin has a tapered end so that the pin will extend through the body rail hole prior to advancing to the fully locked position.

Abstract: The invention concerns a device for adjusting a fifth wheel, comprising a displacement device provided with two guide rails placed on the vehicle, in particular on a tractor semi-trailer combination in the longitudinal direction thereof, said guide rails whereon a slide may be installed capable of being moved by means of an actuating device, said actuating device being designed such that, upon a displacement, the positive connection between the guide rails and the slide is maintained. The invention is characterized in that said actuating device which is designed to move the slide, comprises a first powered device. Additionally, at least one first position sensor is arranged to detect the position of the slide, at least said first position sensor being connected to a control device.

Abstract: A slide rail assembly for a fifth wheel hitch assembly is disclosed that includes an angle member for directly mounting the assembly to a truck frame member, and a t-shaped slide rail attached to a horizontal portion of the angle member, the t-shaped slide rail including a row of spaced gaps.

Abstract: A fifth wheel assembly comprises a fifth wheel having a plurality of journal bearings extending generally downward from its underside, and an “I-shaped” transverse beam member for mounting the assembly to a truck frame. The beam member is dimensioned to span across parallel longitudinal truck frame members and it includes mounting flanges extending generally downward from either lateral side where the mounting flanges have a plurality of apertures for receiving suitable fasteners inserted therein for mounting said beam member to the truck frame members. The transverse member also includes a plurality of pivot bearing pairs to receive the journal bearings of the fifth wheel which is coupled thereto by a trunnion.

Abstract: Improved trailers (e.g., semi-trailers) are disclosed. The trailers may include a floor having a top surface and a bottom surface, where the top surface is adapted to transport a payload, and an elongated shell connected to the bottom surface of the floor, where the elongated shell defines a portion of a substantially closed torsion-resistant chamber of the trailer. The trailers may have a torsion resistance that is substantially higher than conventional trailers of similar size and/or load capacity. The trailers may weigh substantially less than conventional trailers of similar size and/or load capacity. The trailers may realize a bending resistance that is at least equivalent to the bending resistance of conventional trailers of similar size and/or load capacity.

Abstract: A sliding suspension includes a plurality of locking pins that are selectively moved between extended and retracted positions to allow adjustment of the sliding suspension relative to a trailer frame structure. A lever is fixed to a tube that is supported by a cross-member of a slider frame. A cam is supported on the tube for rotational movement relative to the tube. Laterally spaced locking pins each include a pin connection link that is coupled to the cam. Each locking pin includes a single compression spring, and each pin connection link includes a slot, which cooperate with each other to provide independent pin extension at each pin location. A torsion spring is coaxial with the tube and includes one spring end that is coupled to the lever and another spring end that is coupled to the cam. The torsion spring allows the lever to be decoupled from the locking pins if one or more pins are stuck such that the pull handle can be pulled and locked into place to allow adjustment.

Abstract: A disengagement assembly for maintaining a disengaging force on a tandem assembly. The disengagement assembly operates with an actuating arm of a retractable pin assembly of a tandem wherein the actuating arm reciprocates between an engaged position and a disengaged position. The disengagement assembly maintains an applied force on the actuating arm in the disengaged position so that the tandem remains in a movable relationship with respect to frame members of a trailer.

Abstract: A lowboy trailer is described having a pair of rear wheel assemblies mounted to a chassis of the trailer for movement between transport and loading positions such that the wheel assemblies are aligned across a back of the body when they are in the transport position and raised and positioned outwardly when the chassis is in the loading position. A linkage mechanism moves each of the wheel assemblies between the transport and loading positions. Each linkage mechanism automatically fastens the wheel assembly to the chassis of the trailer when the assembly is moved to its transport position. In operation, each of the wheel assemblies is moved from its transport position to the loading position by first moving to an intermediate raised position. By moving the wheel assemblies to the raised position they are automatically unfastened from the chassis and freed to move outwardly about a vertical pivot axis.

Abstract: A fifth wheel assembly comprises a fifth wheel having a plurality of journal bearings extending generally downward from its underside, and a transverse beam member for mounting the assembly to a truck frame. The beam member is dimensioned to span across parallel longitudinal truck frame members and it includes mounting flanges extending generally downward from either lateral side where the mounting flanges have a plurality of apertures for receiving suitable fasteners inserted therein for mounting said beam member to the truck frame members. The transverse member also includes a plurality of pivot bearing pairs to receive the journal bearings of the fifth wheel which is coupled thereto by a trunnion.

Abstract: A slidable trailer hitch apparatus comprises a trailer hitch head operable to receive a cooperating portion of a trailer, the trailer hitch head adapted to be slidable and rotatable relative to the vehicle about an axis of rotation, first and second parallel spaced part guides fixedly located relative to the vehicle, and a body affixed to and rotatable with the trailer hitch head, the body having a center of rotation about the axis and a distal surface adapted to engage either of the first or second guides when the body is rotated relative to the first and second guides. The engagement of the distal surface upon either of the first or second guides displaces the center of the body and the trailer hitch head parallel to the first or second guide when the trailer hitch head is rotated relative to the first and second guides.

Abstract: A portable rock crawl course, including one or more trailers, each having a trailer bed, side walls, top panels, front end wall, and tailgate, each having synthetic rocks formed thereon and arranged such that when the walls, top panels and tailgates are pivoted to form a closed trailer, the synthetic rocks are nested inside and such that the side and end walls, top panels and tailgate are pivotable to form a crawl course over which vehicles travel, and wherein multiple trailers can be arranged to form multiple trailer crawl courses.

Abstract: A compact, portable locking pin locator device adapted to assist the driver of a semi truck including a tractor and a trailer to locate the trailer over the tandem axle under the back end of the trailer to achieve proper weight and balance of the load carried in the trailer over the wheels of the truck.

Abstract: A locking pin system is operated through an air spring which rotates a torque tube to remove a spring bias from a multiple of locking pins. Operation of the locking pin system is controlled by a trailer spring brake valve which operates in response to actuation of the slider parking brakes.

Abstract: The invention provides a trailer for use as part of an articulated vehicle (15) with improved cornering characteristics. The trailer includes: a main chassis (18) connectable to a wheeled section (16) of the vehicle immediately ahead of the trailer so that the trailer is rotatable relative to the wheeled section (16) about a substantially upright first axis (19) in the main chassis (18); a sub-chassis (20) having ground-engaging wheels (21) mounted thereto, the sub-chassis (20) being connected to the main chassis (18) and pivotable about a substantially upright second axis (23) in the main chassis (18); and stop means arranged for limiting rotation of the sub-chassis (20) about the second axis (23) and away from a position of a longitudinal alignment with the main chassis (18). The stop means is movable responsively to relative rotation of the wheeled section (16) and the main chassis (18) about the first axis (19).

Abstract: A carrier assembly is mounted on the spaced frame members of a tractor for movably supporting a fifth wheel assembly thereon. An integral one piece slide rail is secured to each of the frame members and has a plurality of individual rack sections separately welded to a U-shaped member of the slide rail. Each of the rack sections contain a plurality of spaced teeth. The teeth extend into a channel formed in mounting brackets of a carriage assembly of the fifth wheel to slidably mount the carriage assembly on the carrier assembly. A leg of the U-shaped member extends into a channel formed in the carriage assembly and is engaged by a set bolt to adjust the carriage assembly for various frame widths. A pair of stop assemblies are adjustably movably mounted across the ends of the slide rails of the carrier assembly. A pair of adjustable plungers secure the carriage assembly in a fixed position on the carrier assembly.

Abstract: A slider locking pin control receives feedback of the actual position of the locking pins. If the locking pins are not engaged in the trailer frame rails, then the interlock valve will vent air to release a parking brake. Once the locking pins are engaged, the interlock valve will allow the flow of air to release the parking brakes. If the vehicle operator attempts to move the vehicle, but the locking pins are not engaged, the operator will be unable to release the parking brakes. This will prevent movement of the trailer until the locking pins are engaged. The interlock valve is placed downstream of a spring brake control valve and pressurized air reservoir, such that the pressurized air reservoir can still receive pressurized air to charge, and provide air for use by various components on the trailer.

Abstract: A detachable suspension mounting includes a pair of plates each having an upper surface and a lower surface. The upper surface of a first of the plates is fixedly coupled to a bottom side of the trailer. A plurality of securing members selectively secures a second plate of the pair of plates to the first plate such that the upper surface of the second plate is adjacent to the lower surface of the first plate. A suspension is fixedly coupled to the lower surface of the second plate and wheels are rotatably coupled to the suspension.

Abstract: The present invention relates to a system for adjusting weight distribution throughout all axle groups of the truck and trailer. The trailer has at least one axle group mounted on a pair of rails attached to the frame of the trailer. These axle groups are locked in position on the rails by locking pins. The system for adjusting weight distribution according to the present invention measures the weight on every axle group on the truck and trailer. The measurement may be of weight directly by load cells etc. or indirectly, by taking measurements from the air suspension system to calculate weight. The measurements are delivered as an electrical signal to one or more microprocessors capable of receiving the electrical signals and calculating the optimum position of the axle group on the trailer. The position of the trailer axle groups relative to the rails is also determined and the position delivered to the microprocessor(s).

Abstract: A trailer slider pin control system is provided including a vehicle body and a rail supported along the body. The rails are moveable between a plurality of positions defined by a plurality of holes in the rail. A pin assembly is supported on the vehicle body and includes a pin moveable between unlocked and locked positions. The pin is disposed in the hole locking the rail to the vehicle body in the locked position. Conversely, the rail is free to move along the vehicle body in the unlock position. A sensor senses a location of a portion of the pin assembly, which corresponds to the unlock position. A vehicle speed control device, such as an engine, transmission, or braking system, is actuatable to limit the speed of the vehicle. A controller is connected to the sensor and the vehicle speed control device to actuate the vehicle speed control device to limit the speed of the vehicle in response to the sensors sensing the unlocked position.

Abstract: A system for connecting a slider to a trailer frame includes a rotatable locking member having a plurality of teeth that engage with a plurality of openings in the trailer from. The locking member is biased by a rotary biasing in a locked position.

Abstract: An improved suspension system includes a plurality of slider pins which are biased radially outwardly into engagement with openings in the suspension rails of the suspension system and the mating openings in the slider rail. The slider pins are provided with spring clamp structure and a wedged surface. The wedged surface forces the spring clamp radially outwardly into engagement with the openings in the suspension rails to secure the slider pins. Upon withdrawal of the slider pins, the spring clamp is biased radially inwardly to facilitate removal.

Abstract: A number of improved ways of connecting a slider to a trailer frame are disclosed. In one general type of solution, a wedge-shaped locking surface is formed on both the slider and the trailer. The wedged surfaces provide a very secure connection. In another general way of describing the embodiments, several of the embodiments have a plurality of locking surfaces which again provide a more secure connection.

Abstract: A operating system for slider locking pins includes an air compressor connected to an air supply tank. An air pressure protection valve is connected to the air tank to protect the brake system of the trailer. A flipper valve is connected to the air pressure protection valve and provides selective fluid communication between the air tank and a plurality of locking pin driver assemblies. Each locking pin driver assembly is adapted to move a locking pin to a disengaged position when in fluid communication with the air tank while being adapted to move the locking pin to the engaged position when not in fluid communication with the air tank. Each driver assembly is configured to substantially provide protection to each of its elements from adverse weather conditions and articles thrown up from the road. In one embodiment, the driver assembly includes a fixed bracket attached to the frame of the sliding undercarriage. A traveling bracket is connected to a locking pin.

Abstract: A slider pin release mechanism for a slider suspension system of a semi-trailer which includes a trailer body and a slider suspension which is movable longitudinally forwardly and rearwardly relative to the trailer body. Locking pins carried on the slider suspension are movable laterally into and out of locking engagement with the slider suspension and the trailer body. A longitudinally extending pivot rod connects to the locking pins. A ratchet gear is affixed to the forward end of the pivot rod. A handle is mounted on the pivot rod for rotation relative to the ratchet gear. A drive pawl is mounted on the handle and engages the ratchet gear to drive the ratchet gear upon rotation of the handle. A holding pawl is engageable with said ratchet gear. A drive pawl release rod is connected to the drive pawl. The drive pawl includes a release tooth which is moved into contact with the holding pawl to disengage the holding pawl from the ratchet gear.

Abstract: An extension coupling for releasably interconnecting a trailer to a fifth wheel tow hitch. This extension coupling includes a mount that is secured to the trailer, and an elongated arm that is pivotally secured to the mount and one end. A universal joint with lateral pins is attached to the other end of the arm to mate with the tow hitch. This allows the trailer to be displaced rearwardly of the tow hitch a distance equal to the length of the elongated arm while at the same time maintaining the loading point on a tractor vehicle forward of the rear axle. The assembly allows the trailer to pivot normally, without hitting the cab of short-bed pickup trucks. It also ensures that the weight of the trailer is carried forward of the rear axle for stability.

Abstract: A suspension repositioning system for a trailer is provided that includes a trailer frame having spaced apart rails with a plurality of sets of holes in the rails. A suspension unit is movable relative to the frame along the rails. The suspension unit has a set of pins movable between locked and unlocked positions which are engageable with one of the plurality of sets of holes in the locked position to secure the suspension unit to the trailer frame. A speed sensor detects a speed of the suspension unit, and a pin position sensor detects the unlocked position of at least one of the pins. An alarm is connected with the speed sensor and the pin position sensor. The alarm sends an alert signal in response to the speed sensor detecting a predetermined speed and the pin position sensor detecting the at least one of the pins in the unlocked position.

Abstract: A trailer slider pin control system is provided including a vehicle body and a rail supported along the body. The rails are moveable between a plurality of positions defined by a plurality of holes in the rail. A pin assembly is supported on the vehicle body and includes a pin moveable between unlocked and locked positions. The pin is disposed in the hole locking the rail to the vehicle body in the locked position. Conversely, the rail is free to move along the vehicle body in the unlock position. A sensor senses a location of a portion of the pin assembly, which corresponds to the unlock position. A vehicle speed control device, such as an engine, transmission, or braking system, is actuatable to limit the speed of the vehicle. A controller is connected to the sensor and the vehicle speed control device to actuate the vehicle speed control device to limit the speed of the vehicle in response to the sensors sensing the unlocked position.

Abstract: An apertured track and brace system for mounting a slider for adjusting the weight distribution of a semi-trailer. The apertured track is adapted to be mounted to both a semi trailer and to a carriage carrying a rear axle tandem, while a single type of brace is adapted to link the apertured track to other elements operable to slidably longitudinally position the axle tandem relative to the semi trailer itself.

Abstract: A pin retractor operator is provided for use on a trailer having a movable bogie secured to the trailer frame with pins which are retractable by pulling on a handle of a pin retractor. The pin retractor operator includes a case for engaging the bogie, a handle engager coupled to a spring both of which are within the case. A tensioner extends through the case and is coupled to the spring so that linear movement of the tensioner stores energy within the spring when the handle of the pin retractor is received in the handle engager. A regulator coupled to the case controls movement of the tensioner. Tension stored in the spring pulls on the handle of the pin retractor while urging the case against the bogie allowing the trailer to be moved relative to the bogie with the pin retractor operator attached to the bogie. Components of the tensioner are adapted to serve as a positioning mechanism.

Abstract: A locking mechanism for a movable subframe of a semi-trailer includes at least a pair of transversely spaced pins. Each pin is extendable into and retractable from an opening formed in its respective longitudinally extending main member of the subframe and a selected aligned one of a plurality of openings formed in its respective longitudinally extending rail of the trailer main frame. An elastomeric bladder is disposed between the pins and is operatively connected to one or more cables and/or linkage members which in turn are operatively connected to the pins. When the bladder is voided of air and is in its collapsed state, sufficient slack exists in the bladder, cables and/or linkage members to enable the bias force of a coil spring disposed about each of the pins to independently cause the pins to extend through their respective aligned openings to lock the subframe in a selected longitudinal position with respect to the trailer main frame.

Abstract: A locking mechanism for a movable subframe of a semi-trailer includes at least a pair of transversely spaced pins. Each pin is extendable into and retractable from an opening formed in its respective longitudinally extending main member of the subframe and a selected aligned one of a plurality of openings formed in its respective longitudinally extending rail of the trailer main frame. An elastomeric bladder is disposed between the pins and is operatively connected to one or more cables and/or linkage members which in turn are operatively connected to the pins. When the bladder is voided of air and is in its collapsed state, sufficient slack exists in the bladder, cables and/or linkage members to enable the bias force of a coil spring disposed about each of the pins to independently cause the pins to extend through their respective aligned openings to lock the subframe in a selected longitudinal position with respect to the trailer main frame.

Abstract: A method and apparatus involves selectively relieving the load from the rearmost wheels of a trailer to shorten the effective wheel base of the trailer. When the effective wheel base is shortened, off-tracking of the trailer during turning is reduced. The load may relieved while the trailer and vehicle are traveling at, for example, less than a first speed, with the vehicle turning at least at a first angle. The axle may be reloaded when the vehicle speed is increased to a second speed above the first speed and the vehicle is turning at an angle which is less than the first angle.