GB2187151A - Measuring wear in fifth wheel couplings - Google Patents

Abstract

An apparatus for measuring the wear or slack in a fifth-wheel coupling member 32 comprises a Kingpin 11 rigidly connected to a support plate 13 and which is adapted for coupling with the fifth-wheel coupling member 32, and a rod 19 slidably mounted in a tube 15 connected to the support plate 13 and having a bent-over end 21 for engagement with the fifth-wheel coupling member externally of the coupling point. The degree of movement of the rod 19 relative to the support plate 13, as shown by a gauge 26 to 28, indicates the degree of wear or slack in the coupling member. The apparatus preferably includes a spring between the end 21 of the rod 19 and the Kingpin 11. <IMAGE>

Description

SPECIFICATION Fifth-wheel coupling tester This invention relates to an apparatusfortesting a fifth-wheel coupling member of the kind which is mounted on a tractor for coupling the tractor to a trailer. The invention relates, in particular, to an apparatus for indicating the wear or slack in such coupling members.

Atrailerwhich is to be coupled to a tractor or towing vehicle has a pin, known as a "Kingpin", fitted to its underside, this pin interengaging with the fifth-wheel coupling membertoform an articulated trailer/towing vehicle combination. It is necessaryfor all such vehicles to pass a roadworthiness test as outlines by E.E.C. regulations. The testing of fifth-wheel coupling members forms a part ofthe above regulations. The present maximum combined wear or slack allowed between a tractor and trailers one half inch - "forthe Kingpin and 1/4 "forthe fifth-wheel coupling. It is expected that in the near future the maximum combined wear or slack allowed between tractor and trailer will be reduced to 6mm-3mm forthe Kingpin and 3mmforthe fifth-wheel coupling member.

One known method oftesting for wear or slack in a fifth-wheel coupling member is as follows.

First, the trailer and tractor are coupled in the normal manner and the brakes are then applied to thetrailerto immobilise it. An attempt is then made to move the tractor forwards and rearwardsto determine if there is any wear or slack in the fifth-wheel/Kingpin coupling. This test is only a visual test and is unlikely to be acceptable in the future due to the reduced maximum tolerance. This test also does not indicate whether the wear is in the Kingpin or in the fifth-wheel coupling member itself.

Another problem with this test is that it involves coupling a tractor and trailer which is tedious and furthermore, it requires two people, one to drive the tractor and the other to observe any movement.

A known form of apparatus for testing fifth-wheel coupling members is manufactured by Newbridge Metal Products Ltd., County Kildare, Ireland, under licence from Dayton-Walter Ltd., U.S.A. This apparatus basically comprises a flat plate having a pair of handles on its uppermost surface and a Kingpin mounted on its lowermost surface. To use this apparatus, a person must climb on top ofthe tractor and engage the Kingpin in the coupling member. The area of the tractor adjacent to the fifth-wheel coupling member is usually covered with grease and there is a danger that the person using this apparatus may slip.Also, although this apparatus may provide an indication of wear or slackness, it does not provide an accurate measurement of such wear or slackness, and this apparatus is also difficult to handle and awkward to use.

Thus, it is an object ofthe present invention to mitigate the above problems of measuring the wear or slack in fifth-wheel coupling members.

According to the invention there is provided an apparatus for indicating the wear or slack in a fifth-wheel coupling member, comprising a Kingpin fixed relative to a support member and adapted for coupling with a fifth-wheel coupling member, and a slide memberslidablyconnected to the support member and having means for engagement withthe fifth-wheel coupling member externally of the coupling point, the degree of movement of the slide member relative to the support member indicating the degree of wear or slack in the coupling member.

Embodiments of the invention will now be described, by way of example, with reference to and as illustrated in the accompanying drawings, in which: Figure 1 is an underneath perspective view of a first embodiment of an apparatus according to the invention, Figure 2 is a perspective view of the embodiment of Figure 1 in use on a fifth-wheel coupling member, and Figure3 is a top plan view of a second embodimentofthe invention.

Referring now to Figures 1 and 2 of the drawings, wherein similar numerals have been used to indicate like parts, there is shown therein an apparatus 1 0for measuring wear or slack in a fifth-wheel coupling member. The apparatus 10 comprises a conventional Kingpin 11 fixed on the underside 12 of a circular plate 13. One end 140f atubularT-shaped support member 15 is welded to the upper side 16 of the circular plate 13. The other end 17 of the support member 15 has a hollow cross-piece 18 which acts as a handle as will be described. A rod 19 is slidably engaged within the tubular support member 15. As shown, the rod 19 is longer than the support member 15 and projects beyond each end 14,17 ofthe support member.Further, the rod 19 is generally cylindrical for most of its length to be rotatable within the support member 15 but has an end portion 20 which is of substantially rectangular cross-section and has a hook portion 21 which is bent at right angles. The end of the rod 19 adjacent to the cross-piece 18 has engaged thereon a coil spring 23 which acts between the extreme end 24 of the support member 15 and an enlarged end portion 25 of the rod 19. An aperture 26 is defined in the upper surface of the support member 15 and a zero or null position is indicated by a marking 27 on the support member adjacent to the aperture 26. Similarly,a marking 28 is provided on the rod 19 adjacent to the aperture 26so that when the markings 27 and 28 are aligned the Kingpin 11 is at the correct distance from the portion 21. In this position the spring 23 is in compression.

A pair of flat support bars 30 are fixed on the underside 12 of the circular plate 13. As shown in figure 2, these bars 30 in use engage the upper surface 31 of a fifth-wheel coupling member 32. The fifth-wheel coupling member 32 is mounted on the chassis 33 of a conventional tractorortowing vehicle only a portion of which isgenerallyindicated at 34.

The hook portion 21 is engaged overthe front edge 35 ofthefifth-wheel coupling member32 with the Kingpin 11 engaged in normal manner in the coupling member atthe point indicated at 36 which is located underthe plate 13. In this position there should ideally be no relative displacement between the support member 15 and the rod 19, and the markings 27 and 28 should be aligned. Then with the hook portion 21 engaged over the front edge 35 of thefifth-wheel coupling member 32, the cross piece 18 is manually gripped byan operatorand pulled rearwards againstthe bias of the spring 23.If there is any wear or slack atthe coupling point 36the support member 15 will move rearwards relative to the rod 19 and the relative movementwill be indicated buy a displacement of the two markings 27,28. Similarly, if the cross-piece 18 is released the bias of the spring 23 will move the Kingpin 11 towards the portion 21 to indicate any wear in the opposite (forward) direction.

Ascale (not shown) may be located adjacent to the aperture 26 to measure the relative movementwhich may be noted visually on the scale. Alternatively, a clockguage may be incorporated in suitable manner to indicate relative movement between the support member 15and rod 19.

The main advantage of the apparatus is that it is easyto use and provides an accurate indication of wear or slack at the coupling point 36. It may be used by an operator at ground level and it may also be used as an adjustment tool for adjusting the coupling setting ofthefifth-wheel coupling member.

Asecond embodiment of the invention is shown in Figure 3. In this embodiment the circular plate 13 and bars 30 have been replaced by a single generally rectangularflat plate 13' for lightness, and the spring 23 atthe end of the rod 19 remote from the portion 21 has been replaced by a spring 40 which extends around the rod 19 between a flange (not shown) fixed to the end 44 of the member 15 and a further collar or shoulder (not shown) fixed to the inside of thetubularsupportmember15,thespring40 extending inside the member 15 to the further collar.

It will be appreciated thattheflange fixed to the end 44 of the member 15 has an aperture (notshown)to accommodate the rod 19.

In this case the measuring scale which indicates the degree of movement of the rod 19 relative to the tubular support 15 is marked at 42 on the end ofthe rod 19 remote from the portion 21, the null position being indicated by the alignment of a mark on the scale with the end 43 of the member 1 5. Itwill be appreciated that in this embodimentthe spring 40 will be in tension at the null position. Further, a slidable collar45 may be provided on the rod 19 adjacent the end 43 of the member 15, so that priorto use the collar 45 is pushed adjacentthe end 43 and whenthe member15is pulied rearwardsthe movement of the collar 45 provides a measure ofthe movement.

Claims (8)

1. An apparatus for indicating the wear or slack in a fifth-wheel coupling member, comprising a Kingpin fixed relative to a support member and adapted for coupling with a fifth-wheel coupling member, and a slide member slidably connected to the support member and having means for engagementwith the fifth-wheel coupling member externally of the coupling point, the degree of movement of the slide member relative to the support member indicating the degree of or slackinthecoupling member.

2. An apparatus as claimed in Claim 1,further including a resilient coupling between the slide member and the support member.

3. An apparatus as claimed in Claim 2, wherein the support member comprises an elongate slide support means, wherein the slide member comprises a rod slidably mounted in the slide supportmeansand projecting therefrom ateach end, and wherein the engagement means of the slide member is provided at one projecting end ofthe slide member.

4. An apparatus as claimed in Claim 3, wherein the slide support means is a tube in which the slide member is accommodated.

5. An apparatus as claimed in Claim 4, wherein the tube has a cross-piece serving as a handle.

6. An apparatus as claimed in Claim 3,4 or 5, wherein the engagement means ofthe slide member is a bent-over portion of the said one end of the slide member.

7. An apparatus as claimed in any preceding Claim,furthercomprising guage means for indicating the degree of movement of the slide member relative to a null position on the support member.

8. An apparatus as claimed in Claim 1, substantially as described herein with reference to Figures 1 and 2 or Figures 3 of the accompanying drawings.