Abstract: A slide-out undercarriage mounted on an underside of a first trailer pulled by a highway tractor. The slide-out undercarriage is adapted for attaching a rear of the first trailer to a front of a second trailer. The slide-out undercarriage includes a fixed undercarriage frame mounted on an underside of a first trailer. A front axle with front wheels is mounted on a front axle frame and a rear axle with rear wheels is mounted on a rear axle frame. The rear axle frame includes a fifth wheel adapted for engaging a king pin on the front of the second trailer. A pair of first slide out tubes are attached to the front axle frame. A pair of second slide out tubes are attached to the rear axle frame. The first and second slide out tubes provide for allowing an operator of the first trailer to adjust the front and rear axles in various load positions under the first trailer when pulling the second trailer.

Abstract: A system for adjusting a sliding undercarriage along a length of a semitrailer and adjusting a sliding fifth wheel along a length of a tractor. The tractor used for pulling the semitrailer. The system is used for balancing a load on the semitrailer, adjusting the truck and semitrailer turning radius and for operator convenience. The sliding undercarriage and sliding fifth wheel may be adjusted from the cab of the tractor when the tractor and trailer are in operation. The system includes a control panel under computer control. The control panel is received inside the cab of the tractor and electrically connected to a first electric motor and first gear box mounted on the tractor. The first gear box drives a pair of parallel screws threadably attached to a pair of ball screws. The ball screws are secured to the fifth wheel of the tractor. When the first gear box is actuated, the screws attached to the fifth wheel move the fifth wheel forward and aft on the tractor.

Abstract: A locking system for securing an expandable semitrailer chassis and for securing a removable container received on top of the chassis when the container is transported on the semitrailer. The expandable semitrailer allows for receiving different lengths of removable containers thereon. The semitrailer pulled by a tractor. In one embodiment the locking system is used with the expandable chassis for securing and releasing a telescoping rail slidably mounted inside a rail receiving member. The chassis includes the telescoping rail cross beam support members and rail receiving member. The chassis is supported on an undercarriage. The rail receiving member include spaced apart locking pin holes disposed along the length thereof. The locking system includes an air cylinders with piston. The air cylinder is mounted on a rail crossbar and disposed next to pin holes in the rail receiving member.

Abstract: A locking system with air pressure protection valve mounted on a sliding undercarriage of a semitrailer, the semitrailer pulled by a tractor. The locking system is used for securing and releasing the sliding undercarriage from a pair of parallel rails mounted on an underside of the semitrailer. The locking system may be a pneumatic system or electro-pneumatic system and includes at least one air cylinder with piston. The air cylinder is mounted on the sliding undercarriage and disposed next to the parallel rails. A locking pin is attached to the piston with a portion of the locking pin inserted into selected locking pin hole in a locked position in the parallel rails. An air valve directs pressurized air to the air cylinder for retracting and extending the piston. The air pressure protection valve is attached between a pressurized air source and the air valve and prevents the operation of the air valve if the air pressure in the pressurized air source drops below a predetermined amount of air pressure.

Abstract: Improved locking pins and parallel rails used with a locking pin system mounted on a sliding undercarriage of a semitrailer. The locking pin system used for securing and releasing a sliding undercarriage from a pair of the parallel rails mounted on an underside of the semitrailer. The parallel rails have spaced apart locking pin holes. The rails are designed to withstand dynamic loads placed thereon when the pins are extended against the rails prior to being received in the next available pin holes. The new locking pins are integrally formed in a one piece construction and are substantial cylindrical in shape. Each pin is characterized by having a flat circular insertion end with a pin hole entry collar. The pin hole entry collar is circular having a diameter in a range of one half to three quarters of the diameter of the locking pin hole. From the pin hole entry collar and extending rearwardly is an outwardly tapered center portion connected to a pin hole seating collar.

Abstract: A pneumatic locking system mounted on a sliding undercarriage of a semitrailer, the semitrailer pulled by a tractor. The locking system is used for securing and releasing a sliding undercarriage from a pair of parallel rails mounted on an underside of the semitrailer, the parallel rails having spaced apart locking pin holes along their length. The locking system includes one pair or two pair of air cylinders with pistons. The air cylinders are mounted on the sliding undercarriage and disposed next to the parallel rails. Locking pins are attached to each piston with a portion of the locking pins inserted into selected locking pins holes in the parallel rails when in a locked position. A 4-way air valve is connected to the air cylinders and a pressurized air source on the semitrailer. The air valve directs pressurized air to the air cylinders for retracting and extending the pistons in the cylinder. An air pressure switch is connected to a pressurized air line to the semitrailer air brakes.

Abstract: A locking system mounted on a semitrailer sliding undercarriage and used for securing and releasing the sliding undercarriage from an underside of a semitrailer. The sliding undercarriage is also known commonly in the trucking industry as a sliding tandem and further referred to as a longitudinally shiftable running gear. The system includes two or more air cylinders mounted on the sliding undercarriage. Each air cylinder is attached to a locking pin which is inserted into locking pin holes disposed along a length of a pair of parallel rails. The rails are mounted on the underside of the semitrailer. The system prevents retraction of the locking pins if the semitrailer brakes have not been set. Further, the system is fail-safe and automatically reinserts the locking pins in the locking pin holes if the power to a control panel is interrupted or air pressure is applied to release the semitrailer's air brakes. The air cylinders have electronic position sensors wired to the control panel.