GB2215691A

GB2215691A - Bearing arrangement for coupling plate of a fifth wheel coupling

Info

Publication number: GB2215691A
Application number: GB8902140A
Authority: GB
Inventors: Lothar Jakob
Original assignee: Georg Fischer AG
Current assignee: Georg Fischer AG
Priority date: 1988-02-09
Filing date: 1989-02-01
Publication date: 1989-09-27
Anticipated expiration: 2009-02-01
Also published as: SE468892B; SE8900435D0; DE3803815C2; CH676831A5; FR2626835B1; GB8902140D0; DE3803815A1; SE8900435L; GB2215691B; IT8919227A0; FR2626835A1; IT1228057B

Description

SADDLE COUPLING The present invention relates to a saddle coupling for connecting a towing vehicle to a vehicle to be towed.

Commonly, the coupling is arranged, with a kingpin on the semi-trailer or vehicle to be towed and with a coupling plate which receives the kingpin in a slit with run-in bevels and a seal. The coupling plate is supported on at least two pillow blocks, arranged on both sides of the slit by means of a hemispherical bearing head located in a hemispherical bearing shell, wherein the pillow block is attached to the tractor or towing vehicle by way of wall members which are inclined to the horizontal.

With saddle couplings, the semi-trailer is supported by means of a slide plate disposed on the coupling plate provided on the towing vehicle or. tractor. It is primarily the vertical forces which are absorbed by way of these plates. In addition, a kingpin is arranged on the semi-trailer and is received by a slit in the coupling plate on the tractor. The kingpin is locked in the coupling position by means of a lock which at least partly embraces it. It is primarily the horizontal forces which are transmitted via the kingpin. In order to equalize bending movements between the vehicle and semi-trailer, and to facilitate the coupling process, the coupling plate is mounted with limited pivotability about an axis running transverse to the longitudinal axis of the vehicle.

This pivotability is facilitated by one or more pillow blocks attached to the sub-frame of the tractor and which support the coupling plate.

With regard to the support of the coupling plate, there are basically two types of saddle coupling. The first type comprises journal/pivot bearings in which the coupling plate is equipped with journals which are seated in an all-round closed bearing and is disclosed in published German Patent Application 1 655 555 and in German Gebrauchmuster 1 936 350. The second type is related to the saddle coupling outlined above and comprises a simple shell-type bearing and is disclosed in published European Patent Application 0 038 928 and German Patents 1 031 141,1 205 394 and 2 303 163. For this purpose the pillow block has a bearing head on which the coupling plate rests by means of an appropriate bearing shell. To prevent the coupling place lifting off the pillow block cross-bolts are provided, which are attached to the coupling plate and pass through the bearing head.

Since it is advantageous to use the minimum amount of material while providing for the greatest possible stability, present saddle couplings commonly comprise those in which the bearing head is formed as a circular tubular profile on the pillow block, or those which have two pillow blocks and which are each provided with hemispherical bearing heads.'In this case the pillow block has inclined wall members which have terminal flanges for fixture to the vehicle sub-frame as is disclosed in published German Patent Application 2 303 163 and published European Patent Application 0 038 928.

A further requirement is for as low a centre of gravity as possible for the tractor. This necessitates a low arrangement of the pillow blocks, which can be

achieved by providing wall members having a small degree of inclination and also by arranging the bearing head supported by them to be only partly cylindrical or hemispherical. However, in order to obtain a sufficiently large bearing surface, the wall members must extend from the lower region of the bearing head.

When the pillow block is under load a disadvantageously high amount of stress is experienced at the transition between the wall member and bearing head, particularly due to the small angle of inclination of the wall members. In addition, by virtue of the essentially free support of the bearing head, the pillow block does not exhibit optimum rigidity.

Commonly, the pillow block is designed as a single casting, together with the bearing head, the walls and the terminal fixing flanges so as to minimize the use of materials and the cost of installation. Since the bearing head consists of a hollow profile, manufacture is only possible as cored work.

It would be advantageous if a saddle coupling could be provided which did not exhibit the above disadvantages. The present invention seeks to provide a saddle coupling having a high degree of. rigidity, an improved load distribution and a lower structural height (lower centre of gravity), and which may be madeby cost effective production methods.

According to the present invention there is provided a saddle coupling for connecting a towing vehicle to a semi-trailer, including a kingpin arranged on the semi-trailer and a coupling plate for receiving the kingpin in a slit with run-in bevels and a seal, wherein the coupling plate is supported on each of at least two pillow blocks, arranged on opposite sides of the slit, by means of a substantially hemispherical bearing head received in a substantially hemispherical

bearing shell, and wherein the hemispherical bearing head is arranged on the underside of the coupling plate and the hemispherical bearing shell is arranged on the pillow block and is connected thereto by inclined wall means.

The design of the saddle coupling according to the present invention provides the advantage that the bearing shell can rest on the pillow block with its lower crown in the region of the attachment plane of the pillow block, so that the bearing as whole assumes the lowest possible position, thereby minimizing the structural height of the pillow block and thus the height of the saddle coupling as a whole. In addition it also provides for a favourable position of the centre of gravity for the trailer. Further, the arrangement of the bearing shell on the pillow block provides the possibility of arranging the wall means in the region of the top edge of the bearing shell, so that they assume a steeper angle of inclination without increasing the structural height of the coupling, and thereby permitting a more favourable forcedistribution. Also, the stress at the transition between the wall members and the bearing shell is reduced, and an overall greater rigidity is achieved.

Preferably, the bearing shell of the pillow block has its lower crown in the region of the attachment plane of the pillow block and is thereby supported on the tractor. By virtue of the direct support of the bearing shell in the region of its lower crown on the tractor, the vertical forces are introduced into the sub-frame essentially vertically and radially, and the inclined supporting wall means are thus largely relieved of stress. The wall means therefore experience the tensile and transverse forces.

Advantageously, the bearing shell can have a short

projection at its lower crown, by which it is supported on the tractor, and wherein provision is preferably made for the projection to be part of a supporting wall extending as far as the top edge of the bearing shell and arranged in the perpendicular diametric plane of the bearing shell. In this way, the vertical force is transmitted directly to the sub-frame by way of the entire circumference of the bearing shell.

A further advantageous feature of the present invention is characterized by the fact that the hemispherical bearing head is hollow in form and is covered by a plate set into the surface of the coupling plate. In this manner it is possible to produce the bearing head by coreless casting as a single-piece part of the coupling plate, thereby reducing production costs. Also, the plate sealing the top of the bearing head can be designed as a sealing plate, i. e. it can consist of a material best suited for c. he application and for the particular location of use. The pillow block, with its cavities open on opposite sides, can also be produced as a coreless casting.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which: Fig 1 illustrates a longitudinal sectioned side view through one embodiment of a saddle coupling according to the present invention in the region of a pillow block; and Fig 2 illustrates a section through the saddle coupling of fig 1 perpendicular thereto.

The saddle coupling illustrated in the drawings comprises a coupling plate 1 arranged on a towing vehicle or tractor (not shown). The plate 1 is supported on the sub-frame (not shown) of the tractor

via a pillow block 2 located on each side of the kingpin or of a slit receiving the kingpin. The pillow block 2 has a semi-spherical, preferably hemispherical c bearing shell 3 which opens upwards. In the region of the top boundary edges of the bearing shell 3, wall members 4 are arranged at opposite sides of the shell 3. The wall members 4 are inclined in relation to the plane 5 of attachment ot the towing vehicle (not shown). The wall members 4 have strip-like flanges 6 at their end remote from the shell, which flanges 6 are provided with holes 7 in a standard hole-pattern. The pillow block 2 is bolted to the sub-frame of the towing vehicle.

The bearing shell 3 of the pillow block 2 is provided with a short projection 8 in the region of its lower crown. The lower face of the projection 8 extends to the fixing plane 5 and consequently rests on the sub-frame. A lubricating hole 9 is provided n the region of the short projection 8. The projection 8 forms part of a vertical supporting wall 17 located in the diametric plane of the bearing shell (see Fig 2).

The bearing shell 3 is thus supported over its entire diameter via a surface strip on the sub-frame.

The coupling plate 1 has a bearing head 10, designed as a single piece therewith, which has, on its outside, a semi-spherical, preferably hemispherical, bearing surface 11. As is apparent from the drawing, the bearing head 10 is designed with a hollow profile, wherein the inner wall 12 is void of undercuts. The cavity of the bearing head 10 is covered by a sealing plate 13, which is fitted flush into the coupling plate 1 and is fixed with bolts 14. In this way the coupling plate 1 can be produced with the bearing head 10 as a

single-piece core-less casting. \ In its side region, the bearing head 10 has

recesses 15 with which a pin 16, attached to the pillow block, engages so as to secure the coupling plate 1 to the pillow block 2,. and thus prevent the plate 1 from lifting from the pillow block 2.

Claims

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CLAIMS 1. A saddle coupling for connecting a towing vehicle to a semi-trailer, including a kingpin arranged on the semi-trailer and a coupling plate for receiving the kingpin in a slit with run-in bevels and a seal, wherein the coupling plate is supported on each of at least two pillow blocks, arranged on opposite sides of the slit, by means of a substantially hemispherical bearing head received in a substantially hemispherical bearing shell, and wherein the hemispherical bearing head is arranged on the underside of the coupling plate and the hemispherical bearing shell is arranged on the pillow block, and is connected thereto by inclined wall means.
2. A saddle coupling as claimed in claim 1, wherein the inclined wall means extend from the region of the top edges of the bearing shell.
3. A saddle coupling as claimed in claim 1 or 2, wherein the bearing shell is arranged with its lower crown in the region of the plane of attachment of the pillow block to the towing vehicle and is thereby supported on the towing vehicle.
4. A saddle coupling as claimed in claim 1,2 or 3, wherein the bearing shell has a short projection extending from its lower crown and by means of which it is supported on the towing vehicle.
5. A saddle coupling as claimed in claim 4, wherein the projection acts ion combination with a supporting wall which is arranged in the perpendicular diametric place of the bearing shell and which extends from the upper edge of the bearing shell.
6. A saddle coupling as claimed in any preceding claim, wherein the hemispherical bearing head is hollow and is covered by a plate set into the coupling plate

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flush with its surface.
7. A saddle coupling as claimed in claim 6, wherein the plate set into the coupling plate is designed as a sealing plate.
8. A saddle coupling for connecting a towing vehicle to a trailer substantially as hereinbefore described with reference to the accompanying drawings.