Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
2000-09-20
2003-09-23
Morris, Lesley D. (Department: 3611)
Land vehicles
Wheeled
Articulated vehicle
C384S421000
Reexamination Certificate
active
06623024
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a fifth wheel coupling for the articulated connection of a tractor to a semitrailer, with a fifth wheel coupling plate secured by bearing elements on the tractor, having a cutout with a central recess and a lock for accommodation of a kingpin permanently mounted on the semitrailer at the center of an upper plate, and which has a friction-reducing sliding layer.
BACKGROUND OF THE INVENTION
Fifth wheel couplings are used for form-fitting, yet articulated connection of a tractor to a semitrailer, which then together form a so-called double train. The fifth wheel coupling has a fifth wheel plate with a typically V-shaped or mouthlike insertion cutout, also known as the coupling or capture mouth, which is bounded on both sides by a somewhat downward sloping horn. The V-shaped notch is typical, but not necessary. There can also be a coupling from above in the cutout. The insert cutout, the coupling mouth, passes into a central recess, in which a wearing ring is typically but not necessarily placed. On either side of the wearing ring, if present, there are lock elements, especially a locking hook, which are disengaged from the central recess when the fifth wheel coupling is open. The coupling plate can swivel and is joined to the frame of the tractor primarily by means of bearing blocks and possibly a mounting plate.
On the semitrailer, at the bottom of the front end, there is an upper plate on which is arranged a downwardly pointing coupling or kingpin. In the coupling process, this pin is guided by the coupling mouth in the coupling plate and inserted into its central recess until it comes to lie against the wearing ring. The upper plate forms, as it were, the counterplate to the coupling plate. As soon as the kingpin lies against the wearing ring, the lock elements are brought into the locking position, whereupon the locking hook embraces the kingpin with form fit, yet able to rotate.
Fifth wheel couplings of the above kind are generally known and are largely standard equipment on double trains (DIN74080=ISO 337).
Fifth wheel couplings of the above kind must satisfy several requirements. The weight of the semitrailer, the supporting or surface load, as well as all tensile and compressive forces occurring during turns and uphill travel, which are introduced via the kingpin, must be transmitted to the frame of the tractor. Coupling plates which according to the state of art were heretofore exclusively single-piece design (for example, see DE 296 03 641 U1) therefore have to be massively constructed in order to absorb the aforesaid forces. As a consequence, a relatively large amount of material is required for the production of the coupling plate and this is therefore correspondingly heavy.
Another fundamental problem with such couplings is the friction between the coupling plate and the upper plate on the semitrailer, especially because of the constant relative motions between them while traveling on curves.
In order to deal with this problem, it is known (DE 35 30 467 A1; EP 0 117 319 B1; DE 44 18 533 C2) how to provide a coating or fastening of antifriction materials on the coupling plate. Usually these antifriction materials have the form of arc-shaped sliding coatings which preferably consist of plastic and which are embedded in corresponding recesses in the metallic coupling plate and secured there, for example, by gluing or preferably by screwing, so that the sliding layer projects somewhat above the metallic coupling plate. The sliding layer can be bent like a horseshoe or have two approximately semicircular sliding layers, as in the case of the aforesaid DE 296 03 641 U1, which are screwed together with the coupling plate.
SUMMARY OF THE INVENTION
The basic goal of the invention is to configure the above-mentioned fifth wheel coupling such that, while reducing the material outlay, its weight is considerably decreased and a modular construction is possible.
The solution of this problem, according to the invention, is that the coupling plate consists of two mechanically connectable, separate structural components, with an upper bearing component, which interacts with the upper plate, and with a lower carrying component, in which the central cavity with the lock is placed.
The lower beamlike carrying component is basically assigned the function of transmitting the force from the kingpin to the bearing and, thus, to the frame of the tractor. It accommodates the locking mechanism with the wearing ring, if present.
In the fifth wheel coupling according to the invention, therefore, only the lower beamlike carrying component absorbs the support load and the large forces introduced by the kingpin, namely, the tensile forces when traveling on level and rising terrain, the compressive forces on falling terrain, as well as the transverse and lift forces when traveling on curves, so that only this carrying component needs to be mechanically stable in configuration, and a considerable savings in material can be achieved thanks to the beamlike construction. The upper plate-like bearing component need only be designed for the surface load of the semitrailer, also known as the vertical load, since its only task is to bundle the forces originating in the upper plate of the semitrailer and to transfer them to the carrying component, and therefore certain degrees of freedom in design result in terms of the shape of this component and the materials used for its production.
Another task of the bearing component is to provide low frictional moments when traveling on curves.
Since the upper bearing component is exposed to the greatest wear, besides the friction in the wearing ring (if present), now that it is free from the function of absorbing the considerable forces produced by the kingpin it can be designed, in particular by choice of appropriate materials, specifically for the requirements of:
low maintenance
corrosion protection
low weight.
The breaking up of the functions of a fifth wheel coupling between the two components also enables a modular design with great benefit.
One can keep in stock lower beam carrying components designed for different load uptake in the manner of a prefabricated unit and combine them in easy and economical fashion with upper bearing components of various design.
According to a first embodiment of the invention, the bearing component is screwed together with the carrying component. This embodiment allows a simple construction.
Several structural options are available to the practitioner for the connection of the two components. Preferably, because it allows a good and easy to produce fastening, the connection of the two components is by means of screws. For this, according to another embodiment of the invention, a circular ring-shaped molding with several fastening holes is provided on the lower beamlike carrying component, and a congruent crown of fastening holes is provided on the upper bearing component to receive fastening screws.
By separating the functions, one obtains degrees of freedom in the configuration of the upper bearing component. Thus, according to one embodiment of the invention, it is possible to make them out of metal, preferably steel, or aluminum or cast iron. Connection elements can be provided on it for a preferably form-fitting connection to sliding linings forming a sliding layer.
One alternative to this is to coat the entire upper bearing component with a sliding layer, consisting preferably of a plastic which has good sliding properties, like teflon, and which forms a corrosion protection for the steel plate.
According to another embodiment of the invention, the upper bearing component can consist entirely of plastic. The plastic is preferably a fiberglass-reinforced plastic and/or has a reinforcement in the form of embedded pieces. It can also be a multilayered body, with a lower carrying layer and an upper sliding layer.
There are also several possible configurations for the horns bordering the typically V-shaped notch. Thus, these horns can be formed either on the upper bearing com
Alguera Gallego José Manuel
Koetter Stefan
Spitz Rainer
Hudak, Shunk & Farine Co. LPA
Jost--Werke AG
Morris Lesley D.
Winner Tony
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