Abstract: An improved coupling device for connecting a towing vehicle to a semi-trailer and including a kingpin for attachment to a trailer and a tractor coupling plate for attachment to a towing vehicle, the tractor coupling plate having locking elements for positive and rotatable grasping of substantially rotationally symmetrical surfaces of the kingpin. The kingpin surfaces are formed by the outer surfaces of a thermally coated sleeve disposed about a kingpin stud and rotatable thereon. A method for corresponding modification of used coupling devices is also disclosed.

Abstract: A coupling device for connecting a trailer to a towing vehicle is provided. The coupling comprises a drawbar with a first drawbar eye having a first inner diameter, and at least a second drawbar eye having a second inner diameter. A coupling pin of a coupling element on a towing vehicle is adapted to be stucked through one of the two drawbar eyes for coupling the drawbar to the trailer coupling element. The drawbar is adapted to be pivoted by means of a swivel-joint and to swivel in a horizontal plane about at least 180.degree., and to be secured to said coupling. Further, the trailer coupling element comprises, at its free end, two horizontal legs arranged one upon another between which the drawbar is pivoted, and at least one releasable locking pin is provided being stucked through the two legs and through one of the two drawbar eyes located between the legs for locking the drawbar at the forked drawbar (FIG. 2 ).

Abstract: A hydraulically-operated support device for semitrailers is disclosed comprising a hydraulic cylinder semitrailer support and a pump subassembly having three independently operable pumps for generating and controlling the hydraulic operating pressure. The hydraulic cylinder semitrailer support has an extending piston in an extending cylinder, in the bottom end of which is formed a load-raising cylinder for a load raising-piston. A first annular space is formed between the extending piston and the extending cylinder and a second annular space is formed between the load-raising piston and the load-raising cylinder. The annular spaces allow application of pressure in the retraction direction. The pump subassembly comprises an extending pump acting on the extending piston, a load-raising pump acting on the load-raising piston and a retracting pump acting on the annular spaces.

Abstract: A fifth wheel coupling for connection of a semitrailer to a tractor unit is disclosed in which a pair of symmetrical, swivel-articulated closing jaws having semicircular recesses for grasping the king pin have a split bearing comprising an outer bearing half fixed in each closing jaw and inner bearing halves rotatable with respect to the outer bearing halves. The split bearing includes a mechanism for returning each inner bearing half to a position aligned with its respective outer bearing half for uncoupling. The split bearing eliminates friction between the king pin and the closing jaws and is substantially free from wear and maintenance.

Abstract: A fifth wheel coupling for connecting a semitrailer to a towing vehicle, which provides two swivel-articulated closing jaws with semicircular clearances for grasping a semitrailer king pin, and means for opening and closing the jaws which provide a hydraulic cylinder, a piston disposed therein with a rod having a central bore, a tappet disposed within the bore and protruding into the semicircular clearances, piston head and piston rod spaces, and a channel connecting the spaces which is closable by the tappet. Pressurization of the hydraulic cylinder opens the jaws, and contact of the semitrailer king pin against the tappet automatically closes the jaws.

Abstract: Disclosed is a sealing unit comprising a soft sealing ring and a thrust ring which has a greater hardness than the sealing ring. The two rings are permanently connected along a central surface of contact (b). Also disclosed is a process for producing the sealing unit comprising the steps of extruding both the sealing ring and the thrust ring, and then connecting the extruded rings along the central surface of contact.

Abstract: A trailer coupling is provided with a sliding plate and a coupling plate having an anti-friction layer, preferably of a PTFE composite material. To make it possible that in operation the anti-friction surface always remains paired with the same counter surface so that they may matingly wear with each other, a steel plate is placed onto the king journal of the tractor covering the slide plate itself. The steel plate is finished to a depth of roughness of 1 .mu.m. The bore of the steel plate permits passage of the king journal without additional clearance, so that the steel plate is maintained in position by tilting and no further connection is necessary between the steel plate and the slide plate.

Abstract: A packing arrangement for a floating piston dividing a cylinder into first and second chambers comprising a circumferential groove formed in the sliding surface of the floating piston; a circumferential elevation dividing the bottom of the groove into first and second spaces situated on either side of the elevation; backing material placed in the groove; a sealing ring radially situated upon the backing material; first and second extensions on the backing material projecting into the first and second spaces, respectively; each extension having first and second lips forming an annular space between the bottom of the groove and the internal surface of the backing material; the first lip of each extension abutting a lateral wall of the groove and the second lip of each extension abutting a lateral surface of the elevation; a first pressure channel connecting the first chamber with the annular space formed by the first extension; and a second pressure channel connecting the second chamber with the annular space f

Abstract: A guide ring having a seating surface of `U`-shaped cross-section. A plurality of the guide rings may be carried by a piston, piston rod or the like in abutting relation to provide a continuous imperforate surface, or axially spaced from one another with a sealing member interposed between adjacent rings, the sealing member being biased into its operative position by fluid pressure. A ring of resilient material is positioned radially inwardly of the rings and sealing member and is provided with chamfered surfaces which are acted on by biasing means. A sealing arrangement is also provided comprising ring seals and/or stripper rings disposed in a groove in a piston or piston rod and formed of soft material with a lip seal in contact with a surface to be sealed. A shaped sliding ring of abrasion-resistant material which bears on the surface to be sealed is disposed in the ring seal and/or stripper ring.