GB2356908A - Preventing loosening of nuts - Google Patents

Abstract

To prevent loosening of nuts 4, 4', such as wheelnuts, each nut has a ring-shaped element 1, 1' fitted on it with each element having a plurality of external nodes or a single exernal engagement surface (Fig. 11). Adjacent pairs of the elements (Figs 9 and 10) are connected by a respective adjustable strut 7 which acts on nodes or external surfaces of the elements in the tightening direction D of the nuts. Each strut 7 comprises an outer sleeve screwed on a shaft 9, end caps for engagement with elements 1, 1' and a spring clip to retain the strut in its adjusted position.

Description

23569Tx3 NUT LOCK This invention relates to the field of apparatus for

locking nuts so as to reduce their tendency to loosen over time, in -particular but not exclusively, the wheel nuts on a vehicle such as a commercial HGV.

It is a well-recognised problem that the nuts which hold vehicle wheels in place have a tendency to loosen over time through the constant vibration of use and/or poor maintenance.

I n a worst case scenario, the wheel nuts loosen sufficiently for the wheel to come off the vehicle is entirely, wit-h possibly disastrous consequences on a motorway for example.

Various methods and devices are known for locking wheel nuts. For example, a resilient plastics ring is available which is force-fitted over all of the nuts on a wheel, each nut being received in a splined cavity in the ring which grips the nut, reducing its tendency to loosen. However, the manufacturer of this product itself warns "after several occasions of use (about eighteen months to two years of routine service procedures) the Lug Nut Retaining Ring will start to lose its efficiency". It is clear that such a device offers an "all or nothing" solution to the problem of loosening wheel nuts - once the retaining ring has lost its efficiency, none of the nuts will be prevented from loosening.

The "all or nothing" problem is addressed by using a 2 plurality of devices which each lock two or more adjacent nuts together. The plastics nut lock available from Kellett (UK) Limited (advertised and illustrated on page 23 of Commercial Motor 1-7-July 1999) comprises two rings adapted to fit over two adjacent nuts and joined by a resilient link. Splines on the internal surfaces of the rings grip the nuts and the link prevents relative rotation of the two rings, so that each nut effectively holds the other in place.

-his device does, however, suffer from the problem that here is a relati-,,,ely small area of contact: between the sciJines on the rings and tl.-e nu--s -,,V'rich Lhey surround.

This may lead to slippage and hence loosening of the nucs.

The general problem of wheel loss is discussed in Commercial Motor, 2-8 September 1999, pages 36-37, which concludes that "although they [nut-locking methods] offered some comfort against complete loss, they neither gave assurance that enough clamp force was being generated, nor precluded subsequent tightness checks".

There is therefore a need for a wheel nut lock which is cheap to manufacture, given the volume of nut locks required by - a typical fleet, whilst being reliable and effective to resist the tendency of the nuts to loosen over time.

According to the present invention, there is provided a nut lock for locking two or more nuts relative to one another in a common plane, comprising a plurality of shaped ring elements, each adapted to 3 fit over one of said nuts substantially in said common plane; an urging means co-operable simultaneously with two of said ring elements so as to urge each of said ring elements and nuts in the direction of tightening of said nuts.

Preferably, each of said ring elements has an aperture therethrough having the same number of sides as a nut to be locked.

Preferably each of said ring elements is provided with a plurality of nodes at its periphery.

Preferably said urging means is provided with a lock which, when engaged, substantially prevents rotation of said urging means about its longitudinal axis.

Preferably said lock is a spring clip.

Preferably said urging means is provided with means for engaging said two of said ring elements so as to substantially prevent movement thereof out of said common plane.

Preferably the number of nodes is not a factor or a multiple of said number of sides of the aperture.

Preferably the number of nodes is not a multiple of two or three. Ideally the number of nodes is seven.

Preferably said urging means is a turnbuckle.

Preferably said turnbuckle has an internal screw thread at one end thereof. Alternatively said turnbuckle has screw thread at both ends thereof.

Preferably said turnbuckle has a substantially hexagonal cross-section.

Preferably said nodes are substant --Jally semi-circular.

In an alternative embodiment, each of said ring elements comprise an inner, nut-engaging ring cooperable with an outer -zing having a least one node.

Preferred embodiments of -_h_e oresent: invention will -now be more particularly described, by way example only, with reference to the accompanying drawings in which:

Figure!a is a to-- view of a shaped r-ing element or (node wheel) Figure lb is a perspective view of the node wheel of Figure Ia.

Figure 2 is a schematic representation of the node wheels in position on the nuts of a vehicle wheel; Figure 3 is a cross-sectional view of the urging means or turnbuckle; Figure 4 is a schematic view of a spring clip suitable for preventing rotation of the stud; Figure 5 is an exploded view of the turnbuckle, including E the spring clip; Figure 6 shows how the turnbuckle fits between two of the L L.

node wheels in order to lock the wheel nuts in position; Figure 7 shows the correct alignment of a turnbuckle between two node wheels; Figure 8 is an illustration of the 36 unique relative positions available when there are six flats and seven nodes; Figure 9 shows a full set of nut- locks in -rosition on a vehicle wheel (incorrectly aligned) Figure 10 shows a full set of nut locks in position on a vehicle wheel (correctly aligned); and Figure 11 shows an alternative embodiment of the nut locks in position on a vehicle wheel.

Referring to Figure la and 1b, the shaped ring element or "node wheel" 1 comprises a aluminium element having a plurality of substantially semi-circular protrusions or "nodes" which are preferably equally spaced around the ring element 1. The ring element I has a hexagonal aperture 3 therethrough, whose dimensions closely match those of the wheel nuts it is intended to lock.

It will be appreciated that aperture 3 may be another shape, for example a square, if the nut to be locked has more or fewer sides than six. What is important is that the node wheel can be fitted over the nut and prevented from rotation relative thereto by the close fitting of the nut within aperture 3.

The node wheel 1 has a thickness T which can be selected according to the depth of the nut to be locked.

Figure 2 shows how a node wheel 1 can be fitted over each of the nuts 4 on a vehicle wheel 5. Each of the nuts 4 is screwed on to a bolt 6 and it is an object of the present invention to prevent loosening of the nuts 4 on the bolts _L 6 after tightening and once the vehicle is in use.

the nuts '- each fit can be seen from Figure 2 i:l-a-_ s-iu(,gl--%/, within the aperture 3 of t'ne node wheels 1.

The relationship between the hexagonal aperture 3 and the nodes 2 is important. Clearlv, as a wheel nut is tichtened to the required torque, the final orientation of the nut relative to the vehicle wheel cannot be predicted. It is likely that each of the nuts on a single wheel may be aligned differently from one another when each is tightened to the required torque. There is thus a need for the nut lock to be able to cope with as many different orientations of nuts 4 as possible. This issue is discussed in greater detail below with reference to the other key part of the nut lock which is the urging means or turnbuckle.

The urging means is intended to urge, in use, two of the node wheels in the direction of tightening of nuts 4 so as to resist the tendency of the nuts to loosen. The direction of tightening is indicated in Figure 7 and depends on the whether the nut has a left-hand or right- 7 hand screw thread.

A suitable urging means is the turnbuckle 7 shown in Figure 3, although other suitable means can be envisaged.

The turnbuckle 7 comprises a sleeve 8 of hexagonal cross section having a screw-threaded internal surface which co-operates with a screw-threaded shaf t 9 so that the shaft 9 can be screwed into and out of the sleeve 8 as indicated by the arrow in Figure 3.

The turnbuckle 7 is provided with two end caps 10, 11.

Hexagonal end cap 10 is fixed with respect to the screw threaded shaft 9. At the other end of the turn-buckle 7, is hexagonal end cap 11 which is part of a stud 12 which fits into the hexagonal sleeve 8. Optionally, the stud 12 could also be screw-threaded so that it can be screwed in and out of the sleeve in the direction indicated by the arrow in Figure 3. The stud 12 is normally free to rotate with respect to the sleeve 8 about axis X.

The turnbuckle may optionally be made from brass, nylon 66 or other suitable material depending upon the locking force required.

The sleeve 8 need not be of hexagonal cross-section but could, for example, be cylindrical (i.e. circular cross section) and having one or more flats which a spanner can engage so as to rotate the sleeve 8 about its longitudinal axis X.

Each of the end caps 10, 11 has a recess (13,14 respectively) formed therein. The recesses 13 and 14 are shaped to enable them to receive the edge of one of the node wheels 1 and theretore need t -o be large enough to accommodate thickness T shown in Figure 1b. A close fit is preferable so as to minimise movement of the node wheels, in use, relative to the longitudinal axis of the -vehicle wheel bolts 6.

The turnbuckle 7 is provided with apertures 15, 16 which can receive a spring clip 17 (shown more clearly in Figure 4) - The spring clip 17 operates by aligning apertures 15, 16 with corresponding apertures on the end of the stud 12 and engaging the ends of the spring clip in the aligned apertures. The s-cring clip 17, once engaged in this wa-,,,, pre-,,,encs -the sz_ud 12 rotating w i tllri respect to the sleeve a about axis X (shown in Figure 3) is Figure 5 is an exploded view of the turnbuckle, including the spring clip.

Figure 6 shows how the turnbuckle 7 fiLs between two of the node wheels 1 in order to lock the wheel nuts in position. In order to lock two adjacent nuts 4, 4 1, the node wheels 1, 1' are placed over the nuts as shown in Figure 6 and the turnbuckle 7 is placed intermediate the two with the recesses 13, 14 each receiving a node 2 of a node wheel.

if the nodes 2, 21 have the shape illustrated in Figure 6, then it is preferable for the recesses 13, 14 to have a "half-moon" shape so that their curved shape closely abuts the curved outer surface of each node 2, 21 The relative alignment of node 2 and node 2' is fundamental to the effectiveness of the turnbuckle 7.

As mentioned above, the relationship between the number of sides the aperture 3 has and the number of nodes 2 is important. In the preferred embodiment, the number of sides the aperture 3 has (,,number of flats") is six and the number of nodes is seven. This gives a total number of unique relative positions between two adjacent node wheels as 36 (i.e. 66) Figure 8 is an illustration of the 36 unique relative positions starting at 2.5 degrees from top dead centre. 36 is the maximum number of conceivable relative positions of two six-sided figures.

in practice, the total number of unique positions can be doubled by simply flipping over one of the node wheels, is i.e. rotating it 180 degrees about an axis perpendicular to the longitudinal axis of the wheel bolt 6 in Figure 7.

Therefore the total number of unique relative positions is 72.

With this large number of available unique relative positions between two adjacent node wheels, it is easy by trial and error to find an optimum orientation for each of the two node wheels 1, 11 so that the turnbuckle 7 can be ideally positioned, as will be described below.

In the preferred embodiment, the number of flats is six and the number of nodes is seven. However node wheels having different numbers of nodes are envisaged and, indeed, it is possible to apply the device of the present invention to nuts having fewer (or more) than six sides or flats. However it is important to note that the number of unique relative positions can be undesirably reduced if the number of nodes is a multiple or a factor 1. C.

of the number oF flat:s. For example, with the number o'ff flats being six, if there are nine nodes, the number of unique relative positions is 4 (or 8 if one additionally flips over one ol- the node wheels) Generally, where P the number of unique relative positions, F number of flats and N = the number ocL nodes:

P = 2 (most simplified denominator of NIF 2 The ideal posit:ioning of the turnbuckle 7 will no-,,; be more pa-1-:-1cularly described. Figure 6 shows a turnbuc,-,Ie 7 in a non-ideal or "of f line" orientatioz-1. The is longitudinal axis X passes undesirably close to the centre point of bolts 6, 61.

I,- is Dreferable to have the turnbuckle 7 with its axis X in the "correct" alignment shown in Figure 6 and shown most clearly in Figure 7. In this alignment, the turnbuckle 7 urges each of the node wheels 1, 1' (and hence the nuts 4, 4') in their direction of tightening.

in this way the undesirable loosening of the nuts over time is greatly reduced.

Figure 9 shows a full set of nut locks in position on a vehicle wheel 5.. In Figure 9, node wheel numbers 5 and 6 are orientated suitably to allow ideal alignment of the turnbuckle 7 between them. Each of the other illustrated turnbuckles are not ideally aligned because their longitudinal axes pass too close to the centre of the bolts 6.

:::.0 0.: 0.:

0% so a::0 000 004 This problem can be rectified by rotating each of node wheel numbers 1, 3, 7 and 9 clockwise by 60 degrees to the next unique relative position. This results in the correct alignment illustrated in Figure 10.

Fitting instructions for the nut lock of the present invention are as follows:

A. Fit the wheel nuts Clean all mating surfaces with a wire brush to remove any paint, rust or other foreign mattez; Check all screw-threads for damage and ensure that the nuts can be run on the -thread by hand (recommend a rust preventative on the threads before fitting the nuts); Tighten the wheel nuts to the manufacturer's recommended torque; 1B. Fit the nut locks Fit a node wheel over each nut; Place a turnbuckle between two adjacent node wheels so that it points in the direction of tightening (see Figure 7); Rotate one node wheel by one flat (60 degrees) with respect to the nut and repeat until the turnbuckle can be correctly aligned. If necessary flip the node wheel over to double the number of available positions f Rotate the sleeve 8 of the turnbuckle about its longitudinal axis so that the shaft 9 emerges from the SCreW-threaded sleeve 8 and urges each of the caps 10, 11 against their respective node wheels.

Whe-n the turnbuckle is finger-tight, use a 16mm key to give the sleeve a further half turn tighter plus any excra rotation needed to align the holes for the spring clip; Engage the sprIng clip to pre-,,,ent rotation of 7-he L stud 12 and hence the turnbuckle sleeve 8.

Once the vehicle is in use, the wheel nuts should be checked for the correct torcrue after half a day or 200 miles. T-F there has been relief on the wheel nuts, the spring clip should be removed so that. the turnbuckle can be re-adjusted. If there has been significant movement, it may be necessary to re-align the node wheels.

Figure 11 shows an alternative embodiment- CL the nut locks in position on a vehicle wheel.

The nut lock according to the present invention can be utilised on any size of vehicle and wheels having any number of wheel nuts and is suitable for all axles' weights. The nut lock needs little or no maintenance if correctly fitted and will effectively retain vehicle wheels by greatly reducing the tendency of the wheel nuts to loosen. The invention is equally applicable to nuts having left-hand or right-hand screw threads.

It is envisaged that the invention is not limited to the locking of vehicle wheel nuts; it could be used in any situation where two or more nuts in the same plane need to be locked relative to one another.

1 A

Claims (1)

1 Nut- lock for locking two or more nuts relative to one another in a common plane, comprising a plurality of shaped ring elements, each adapted to fit over one of said nuts substantially in said common plane; and an urging means co-operable simultaneously with two of said ring elements so as to urge each of said ring elements and nuts n the direction of tightening of said nuts.

ock. as c., a im ed in claim 1 l.,i-.erein each of said ri, ng element-s has an aperr-ure theretlirough having is the same number of sides as a nut- to be locked.

3. i-,Tut lock as claimed in claim 2 wherein each of said ring elements is c)ro-,rided plurality of nodes at: its -oeri-Qhe--v.

4. Nut lock as claimed in any of the preceding claims wherein said urging means is provided with a lock which, when engaged, substantially prevents rotation of said urging means about its longitudinal axis.

5. Nut lock as claimed in claim 4 wherein said lock is a spring clip.

6. Nut lock as claimed in any of the preceding claims wherein said urging means is provided with means for engaging said t of said ring elements so as to -wo substantially prevent movement thereof out of said common plane.

7. Nut lock as claimed in claim 3 wherein the number of nodes is not a factor or a multiple of said number of sides of the aperture.

8. Nut lock as claimed in claim 3 or claim 7 wherein the number of nodes is not a multiple of two or three.

9. Nut lock as claimed in any of claims 3, 7 or 8 wherein the number of nodes is seven.

10. f the preceding claims Nut lock as claimed in any o.L wherein said urging means is a turnbuckle.

is ii. Nut lock as claimed in claim 10 wherein said turnbuckle has an internal screw thread at one end thereof.

12. Nut lock as claimed in claim 10 wherein said turnbuckle has screw thread at both ends thereof.

13. Nut lock as claimed in any of claims 10 - 12 wherein said turnbuckle has a substantially hexagonal cross- section.

14. Nut lock as claimed in any of claims 3 - 13 wherein said nodes are substantially semi-circular.

15. Nut lock as claimed in any of the preceding claims wherein each of said ring elements comprise an inner, nut-engaging ring cooperable with an outer ring having at least one node.

16. A nut lock substantially as described herein with reference to the accompanying drawings.

17. A vehicle wheel including one or more nut locks as described in any of the preceding claims.

!8. A method of locking nuts using a nut lock as described in any of the preceding clams.

19. A method of locking wheel nuts substantially as described herein with reference to the accompanying drawings.