WO2024261445A1

WO2024261445A1 - Wheel retaining device

Info

Publication number: WO2024261445A1
Application number: PCT/GB2024/000028
Authority: WO
Inventors: Christopher Richard COGHILL
Original assignee: Coghill Christopher Richard
Priority date: 2023-06-23
Filing date: 2024-06-21
Publication date: 2024-12-26
Also published as: GB202309487D0; GB202408980D0; GB2632916A

Abstract

A wheel retaining device comprises threaded wheel studs (12) and threaded wheel nuts (17). Each stud has a longitudinal axial bore (16) and a radial bore (19) intersecting with the longitudinal bore. A locking pin (24) is disposed within the longitudinal bore. Two ball-bearings (33,34) are located within the radial bore. Each wheel nut has an elongate recess (23) extending transversely to a direction of the threads. In a first configuration, the locking pin contacts a first of the ball bearings (33), causing the second of the ball bearings (34) to extend outwardly from the lateral bore into the elongate recess, preventing the wheel nut from turning on the stud. In a second configuration, the first ball bearing moves partially into the longitudinal bore, allowing the second ball bearing to move fully into the lateral bore and out of the elongate recess, freeing the wheel nut to rotate.

Description

WHEEL RETAINING DEVICE

The present invention relates to apparatus to retain a wheel of a vehicle securely attached to the vehicle. More particularly but not exclusively, it relates to a wheel retaining nut that is resistant to coming loose from a wheel hub mounting.

It is conventional for a wheel of a motor vehicle to be secured releasably to a respective wheel hub mounting by means of a plurality of threaded wheel studs that extend outwardly from the wheel hub mounting, which is located on an outer end of an axle of the vehicle. The wheel studs extend through corresponding apertures in a hub portion of the wheel. Co-operating wheel nuts (also known as lug nuts) are threaded on to the studs and tightened on to the wheel hub portion to retain the wheel in place.

On some vehicles, there are instead threaded sockets extending into the wheel hub mounting on the axle, while co-operating wheel bolts (alias lug bolts) are inserted through the apertures in the wheel hub portion and threaded into the sockets. However, these are currently restricted to certain makes of car and are not commonly used on larger vehicles.

It is vitally important that the wheel nuts stay in place to secure the wheel to the axle of the vehicle. If a wheel nut comes loose, then the forces exerted on other wheel nuts on the same wheel will increase, and the other wheel nuts will themselves be more likely to come loose. The forces on a wheel with a loose nut will tend to be unbalanced, varying as the wheel rotates, and leading to vibrations that are both uncomfortable and tend to encourage the other wheel nuts to come loose, in a feedback cycle. These vibrations could even lead to structural distortion and fatigue in the components of the wheel and mounting. Ultimately, loosened wheel nuts could come completely free and the wheel would then part company with the vehicle. For smaller, four-wheeled vehicles, loss of a wheel would probably cause loss of control and a crash. For many-wheeled vehicles, such as heavy goods vehicles and buses, the loss of a particular wheel might or might not be catastrophic for the stability of the vehicle itself, but in any case a wheel coming off the vehicle at speed would have very high momentum and could cause other vehicles to crash or could easily be lethal if the wheel impacted on a bystander.

If wheel nuts are tightened using exactly the right torque, then they will grip the wheel securely to the hub mounting, as designed, and would be unlikely to come loose in use. However, if they are not sufficiently tightened, for whatever reason, then there is an increasing chance that they will become looser, ultimately unthreading completely and falling off.

Another issue is when wheel nuts or studs are damaged, such that there is a loss of engagement which may not be immediately evident, but which can make it easier for the nut to loosen and potentially unthread from the stud. The same effects can result from undetected manufacturing flaws in the wheel nuts or wheel studs.

Also, it is possible for debris to penetrate or become trapped in between components such as the wheel nuts, the wheel studs and even the wheel itself. If this debris is then dislodged, or if it is crushed by the forces imposed on the components in use, then once again the wheel nuts may lose engagement and star to come loose.

Most of these issues ultimately stem from incorrect maintenance and human error. It is therefore desirable to improve procedures and/or equipment to reduce or ideally eliminate the adverse effects of such errors,

Simply tightening the wheel nuts more forcibly on to the wheel studs is not a satisfactory solution. The wheel nuts should not be fastened too tightly, as it must be possible to undo them without excessive effort, in order to remove a wheel and replace it, for example in the event of a flat tyre, or in order to access the wheel hub mounting, brake components located on the respective axle axle or other adjacent portions of the vehicle for maintenance purposes. For much the same reasons, the application of known compositions to the threaded surfaces in order to “lock” the threads, known from other applications, is also not a satisfactory solution.

Overtightened wheel nuts can also cause additional tensile strain on the wheel stud thus leading to metal fatigue, reducing the strength of the stud and leading to component failure. Overtightening of wheel nuts can also damage the threads of the wheel nuts and studs, affecting the engagement between them and thus potentially also increasing the risk of the wheel nuts becoming detached from the wheel studs and hub mounting.

Ideally, all wheel nuts should be correctly tightened and thereafter regularly checked for tightness and condition. However, this puts the entire responsibility for safety on to the vehicle user, which is contrary to optimum principles for safety management. The vehicle operator is legally responsible for daily driver checks and the overall safety of the vehicle, but mistakes can be made, checks can be hurried, and so it is still preferable to provide equipment that lifts some of the burden from the individual. In practice, it is still going to be possible for checks on wheel nuts not to be done often enough or thoroughly enough, whatever the underlying reason.

It is known to position indicating elements on the wheel studs, which are held in place by friction when secured tightly on to the wheel nut. These elements will rotate with the nut, should the nut turn on the stud. If these elements are aligned in a particular direction when the wheel nuts are tightened, a nut that subsequently loosens will show a changed alignment of the indicating element, providing a visual indication that the wheel nut has started to come loose. These devices have been widely adopted and have to some degree improved safety in this respect.

However, these indicating elements still require the vehicle user to make frequent visual assessments of their alignment, and so still leave safety depending essentially on human factors. It is also possible for a careless or lazy user to remove and refit the indicating element manually, without adjusting the tightness and position of the wheel nut itself. In some quarters, there has also grown up an unfounded belief that these indicating devices actually secure the wheel nut and the wheel in place, which might lull inexperienced vehicle users into a false sense of security and discourage regular checks of the wheel nuts and wheel studs themselves. The indicating elements could also potentially obscure the operator’s view of the wheel nuts and studs, preventing the operator from carrying out sufficiently thorough checks of the components of the wheel and its mounting.

In a development of the indicating element concept, a single element is attached to two adjacent wheel nuts with a physical linking element between them. Thus, neither nut should be able to rotate on its respective stud. These arrangements do not however operate as planned if a wheel nut has not been sufficiently tightened when fitted. The nut will still suffer the effects of being loose as set out above/ Also, since the indicating elements are generally made from common thermoplastics materials, the imposed forces may well become enough for the linking element between adjacent nuts to deform and break.

Advanced ABS systems have been developed which can detect the vibrations resulting from a loosening wheel nut at an early stage. However, these systems are currently limited to a few expensive and high performance cars, and as with other systems described herein, they can only indicate when loosening is already under way. In any event, these systems cannot physically resist loosening of a nut, once it is under way.

Systems have been designed in which the wheel nuts comprise washers with a complex cammed arrangement between the washer and the nut proper. These have had some success but have not at the time of filing achieved widespread acceptance. It is believed that it is still important to have these nuts correctly tightened when fitted, and there would still be problems if a wheel nut was incorrectly tightened or if it started to come loose for any other reason.

It is hence an object of the present invention to provide apparatus that obviates the above disadvantages of existing systems for securing a wheel to a vehicle and reduces the likelihood of a wheel nut (or a wheel bolt) becoming detached from a wheel and a wheel hub mounting. It is a further object of the present invention to provide a vehicle operator with such apparatus that provides an operator with an indication that a nut is coming loose. It is also an object of the present invention to provide a method of operation of such apparatus.

According to a first aspect of the present invention, there is provided fastening apparatus for securing a vehicle wheel to a respective hub mounting, comprising a plurality of threaded stud means extending from the hub mounting and so located that the vehicle wheel is locatable on the hub mounting with each said stud means extending through a corresponding aperture in the vehicle wheel, and a plurality of wheel nut means threaded to engage with respective stud means, so as to hold the vehicle wheel securely to the hub mounting; wherein an axial bore extends longitudinally into each said stud means from a distal end thereof, and a radial bore extends inwardly from a threaded surface of each said stud means to intersect with said axial bore; and wherein each stud means comprises: an elongate locking pin longitudinally moveable within said axial bore, and a lateral locking element radially moveable within said radial bore; and wherein: each said locking pin is provided with first recess means adapted to receive a respective first end of the lateral locking element; and each said wheel nut means is provided with second recess means adapted to receive a respective second end of the lateral locking element; each said locking pin being moveable between a first disposition in which its first recess means is aligned with the radial bore, the first end of the lateral locking element is located within the first recess means, and the second end of the lateral locking element is located within the radial bore, and a second disposition in which said first recess means is not aligned with the radial bore, the first end of the lateral locking element is displaced in the direction of the lateral bore, and the second end of the lateral locking element then extends outwardly from the radial bore into the second recess means of the wheel nut means.

Preferably, the locking pin is biased towards said second disposition.

Thus, in said second disposition of the locking pin, the second end of the lateral locking element, extending into the second recess means of the wheel nut means prevents the wheel nut means from rotating on the threaded surface of the respective wheel stud means.

In said first disposition of the locking pin, the second end of the lateral locking element, being disposed within the radial bore and outside the second recess means, allows the wheel nut means to be rotated along the threaded surface of the stud means to fasten or unfasten the wheel nut means. Preferably, the lateral locking element comprises a plurality of separate spherical bodies located within the radial bore.

Advantageously, the lateral locking element comprises two said spherical bodies.

Said two spherical bodies may then comprise the respective first and second ends of the lateral locking element.

Preferably, said first recess means comprises an elongate channel extending longitudinally of the locking pin.

Advantageously, the locking pin is also provided with third recess means, also adapted to receive the first end of the lateral locking element, and comprising an elongate channel extending longitudinally of the locking pin and parallelly to and adjacent the first recess means.

The first and third recess means may be connected adjacent a respective end of each.

Preferably, the locking pin is provided with fourth recess means disposed adjacent an end of the first recess means, also adapted to receive the first end of the lateral locking element, the fourth recess means having a depth substantially less than a depth of the first recess means.

When the first end of the lateral locking element is received in the fourth recess means, it thus extends less far from the radial bore into the axial bore than it does when received in the first recess means.

The second end of the lateral locking element as a result extends outwardly from the radial bore and into the second recess means of the wheel nut means.

Preferably, the second recess means of the wheel nut means is located within a threaded surface thereof.

Advantageously, said second recess means comprises an elongate recess.

Said elongate recess may be extend transversely to a direction of the threads of said threaded surface. Said elongate recess may extend substantially orthogonally to the direction of the threads of said threaded surface.

The elongate recess may be deeper than the threads of said threaded surface.

According to a second aspect of the present invention, there is provided a wheel nut for securing a vehicle wheel to a respective hub mounting, comprising wheel nut means threaded to engage with respective threaded stud means, so as to hold the vehicle wheel securely to the hub mounting; wherein a thread-bearing surface of the wheel nut means is provided with recess means extending transversely to its thread.

Preferably, said recess means comprises an elongate recess.

Said elongate recess may extend substantially orthogonally to a direction of the threads of said threaded surface.

The elongate recess may be deeper than the threads of said threaded surface.

According to a third aspect of the present invention, there is provided a wheel stud for securing a vehicle wheel to a respective hub mounting, comprising a threaded stud means fixedly mountable to the hub mounting and threaded for a wheel nut to engage therewith; wherein an axial bore extends longitudinally into said stud means from a distal end thereof, and a radial bore extends inwardly from a threaded surface of said stud means to intersect with said axial bore; and wherein the stud means comprises: an elongate locking pin longitudinally moveable within said axial bore, and a lateral locking element radially moveable within said radial bore; and wherein: said locking pin is provided with first recess means adapted to receive a first end of the lateral locking element; said locking pin being moveable between: a first disposition in which its first recess means is aligned with the radial bore, the first end of the lateral locking element is located within the first recess means, and a remote second end of the lateral locking element is located within the radial bore, and a second disposition in which said first recess means is not aligned with the radial bore, the first end of the lateral locking element is displaced in the direction of the radial bore, and the second end of the lateral locking element then extends outwardly from the radial bore.

Preferably, the locking pin is biased towards said second disposition.

Preferably, the lateral locking element comprises a plurality of separate spherical bodies located within the radial bore.

When the first end of the lateral locking element is received in the fourth recess means, it thus extends less far into the axial bore than it does when received in the first recess means. The second end of the lateral locking element as a result extends outwardly from the radial bore and into the second recess means of the wheel nut means.

According to a fourth aspect of the present invention, there is provided a hub mounting adapted for a vehicle wheel to be secured thereto, comprising a plurality of threaded stud means as disclosed in the third aspect above, mounted to extend from the hub mounting and so located that the vehicle wheel is locatable on the hub mounting with each said stud means extending through a corresponding aperture in the vehicle wheel.

Preferably, the hub mounting is provided with a plurality of wheel nuts as disclosed in the second aspect above, each adapted to engage with a respective threaded stud means.

According to a fifth aspect of the present invention, there is provided a method for securing a wheel to a vehicle, comprising the steps of: providing fastening apparatus for securing a vehicle wheel to a respective hub mounting, as disclosed in the first aspect above; mounting the threaded stud means thereof to a hub mounting of the vehicle; locating a wheel on the hub mounting with each threaded stud means extending through a respective aperture in a hub portion of the wheel; threading each wheel nut means of the fastening apparatus on to a respective threaded stud means; and tightening each wheel nut means on to the hub portion of the wheel so as to hold the wheel securely between the wheel nut means and the hub mounting.

An embodiment of the present invention will now be more particularly described by way of example and with reference to the Figures of the accompanying drawings, in which:

Figure 1 is a schematic perspective view of a conventional vehicle wheel mounting arrangement;

Figure 2 is a perspective view of a wheel stud of the present invention;

Figure 3 is a perspective view of a wheel nut of the present invention;

Figure 4 is a frontal elevation of a distal end of a wheel nut and wheel stud of the present invention, assembled; Figure 5 is a perspective view of a locking pin separated from a wheel stud of the present invention;

Figure 6 is an alternative perspective view of the locking pin of Figure 5;

Figure 7 is a partially-sectioned lateral elevation of a wheel nut and a wheel stud of the present invention, in a locked configuration;

Figure 8 is a partially-sectioned lateral elevation of the wheel nut and wheel stud of Figure 7, in an unlocked configuration;

Figure 9 is a schematic lateral cross-section of the locking pin of Figure 5 in an unlocked configuration;

Figure 10 is a schematic lateral cross-section of the locking pin of Figure 5 in a locked configuration; and

Figure 11 is a schematic representation of the operation of the locking pin of Figure 5.

Referring now to the Figures, and to Figure 1 in particular, this shows a conventional form of wheel hub mounting for a motor vehicle such as a heavy goods vehicle (HGV), a bus or coach or a van. Wheel hub mountings for smaller vehicles, such as cars and light vans, are generally similar in principle but are usually simpler.

A wheel hub mounting 1 is mounted to one end of an axle of the vehicle (omitted from Figure 1 for clarity). In a conventional arrangement, a plurality of threaded wheel studs 2 are each mounted to extend through a corresponding hole 3 in an annular periphery of the wheel hub mounting 1, so that a threaded shaft of each wheel stud 2 projects outwardly from the wheel hub mounting 1 (only one of these wheel studs 2 is shown in Figure 1 , for simplicity).

A wheel 4 is fitted removably to the wheel hub mounting 1. The wheel 4 has an annular central hub portion 5, which is provided with a plurality of apertures 6. These apertures 6 are arranged so that when the hub portion 5 is offered up to the wheel hub mounting 1 , each aperture 6 may be aligned with a corresponding wheel stud 2 extending from the wheel hub mounting 1.

A wheel nut 7 of conventional form is then threaded on to a distal end of each wheel stud 2 so that an external thread of the wheel stud 2 and an internal thread of the wheel nut 7 engage. The wheel nut 7 is then rotated to travel along the wheel stud 2, until the wheel nut 7 contacts an outer face of the hub portion 5 of the wheel 4, around the respective aperture 6, while an inner face of the hub portion 5 contacts a reverse face of the annular periphery of the wheel hub mounting 1. The wheel nut 7 is then tightened on the wheel stud 2, such that the hub portion 5 of the wheel 4 is firmly gripped between the wheel nut 7 and the wheel hub mounting 1.

In the ideal case, each of the wheel nuts 7 is tightened to such a torque that the wheel 4 is safely held in position, all forces on the wheel 4 are balanced and the wheel nuts 7 do not come loose under the conventional stresses and vibrations experienced in use. If the wheel 4 has to be removed - for example to maintain those brake components that are generally also mounted to the wheel hub mounting 1 , or to change a wheel 4 having a flat tyre - then the wheel nuts 7 can be loosened without applying excessive force/torque and then removed from the respective wheel studs 2. The hub portion 5 of the wheel 4 is then removable from the wheel hub mounting 1.

(Note: the wheel nuts 7 and the apertures 6 are often provided with co-operating coned profiles, to allow easier location and centring of the wheel nuts 7 and the apertures 6, and to provide a greater contact surface between them, spreading the loads imposed thereon. This feature does not affect the operation of the present invention, so has been omitted for simplicity).

In practice, one or more of the wheel nuts 7 may not have been fully tightened, or (for various reasons as set out above) it may start to come loose during operation of the vehicle. Once a wheel nut 7 has begun to loosen, it will usually continue to migrate outwardly along the wheel stud 2 to its distal end and ultimately fall off. Once one wheel nut 7 has come loose, the forces acting on the wheel 4 in normal operation will be concentrated on to other wheel nuts 7, mostly likely the wheel nuts 7 neighbouring the loose wheel nut 7, which will then in turn become more likely to loosen and fall off. Ultimately, if not caught in time, all the wheel nuts 7 will have fallen off, and the wheel 4 will then be free to part company with the vehicle, catastrophically.

The present invention seeks to address this problem.

Figure 2 shows a wheel stud 12 for use in the present invention. This wheel stud 12 has a discoidal base 13 at its proximal end with an elongate cylindrical shaft extending coaxially therefrom. A proximal portion 14 of the shaft is provided with a plurality of splines extending longitudinally along its surface, and a distal portion 15 has a threaded outer surface. (Note: these features are also present in the conventional wheel stud 2 of Figure 1.) For both existing and inventive wheel studs 2,12, the shaft is sized such that its threaded portion 15 can be passed through one of the holes 3 in the wheel hub mounting 1 , while the splined proximal portion 14 fits tightly within the hole 3 and the discoidal base 13 abuts against a reverse face of the wheel hub mounting 1 , thus mounting the wheel stud 2,12 fixedly to the wheel hub mounting 1.

The wheel stud 12 of the present invention has two features not present in the conventional wheel stud 2. An axial bore 16 extends coaxially into the threaded distal portion 15 of the shaft from its distal end face 18, while a lateral bore 19 extends radially into the shaft part-way along the threaded distal portion 15. The lateral bore 19 intersects with the axial bore 16 as described below and illustrated in Figures 7 and 8.

Figure 3 shows a wheel nut 17 for use in the present invention. This wheel nut 17 has a conventional hexagonal-section outer surface 20, a radially-extending basal flange 21 and a threaded central bore 22, which is configured to engage co- operatingly with the threaded distal portion 15 of a wheel stud 2,12.

The wheel nut 17 of the present invention however differs from the conventional wheel nut 7 in that an elongate recess 23 extends longitudinally along the threaded internal surface of the central bore 22. The elongate recess 23 is enclosed at each end, thus stopping short of each end of the threaded central bore 22 and leaving a brief uninterrupted threaded section at either end of the central bore 22.

When the wheel nut 17 is threaded on to the wheel stud 12, this appears when viewed from a distal end of the wheel stud 12 as shown in Figure 4. This view shows more clearly the presence of indicia on the distal end face 18 of the wheel stud 12, just visible in Figure 2. Also visible is a distal end face 25 of a locking pin 24, which is located substantially within the axial bore 16 of the wheel stud 12 (this locking pin 24 is omitted from Figure 2 for clarity). The distal end face 25 of the locking pin 24 also bears indicia. The functions of these indicia will be set out below.

Figures 5 and 6 show the locking pin 24 in more detail, isolated from the wheel stud 12. The locking pin 24 has a generally cylindrical symmetry. A short cylindrical distal cap 26 forms a distal end of the locking pin 24. A circular distal end face of the distal cap 26 comprises the distal end face 25 of the locking pin 24 as a whole, and bears the indicia noted above.

Adjacent the distal cap 26 is a short cylindrical spring support section 27 having a lesser diameter than the distal cap 26 (the respective spring is omitted from Figures 5 and 6 for clarity - see Figure 7 and 8 for details).

A pair of adjacent grooves or channels 28a, 28b extend in parallel longitudinally of a central portion of the locking pin 24. Each groove 28a, 28b has a part-circular crosssection, shown more clearly in Figures 9 and 10.

A first of the grooves 28a extends between the spring support section 27 and a cylindrical proximal end section 30 of the locking pin 24. A second of the grooves 28b extends at its distal end as far as the spring support section 27, but at its proximal end the groove 28b stops short of the proximal end section 30 of the locking pin 24. The two grooves 28a, 28b are connected at their distal ends adjacent the spring support section 27.

Between the proximal end of the second groove 28b and the proximal end section 30 of the locking pin 24, there is located an intermediate platform 29, conveniently formed as a groove shallower than the second groove 28b, but still recessed below the cylindrical profile of the proximal end section 30 (again, see Figures 9 and 10 for more detail).

Figures 7 and 8 illustrate an internal structure of the wheel stud 12 with its locking pin 24 in position. Figures 7 and 8 also show how the wheel stud 12 interacts with the wheel nut 17 in two alternative configurations.

The axial bore 16 extending into the wheel stud 12 from its distal end 18 can be seen to have a profile with two distinct diameters. A wider portion 31 of the axial bore 16 adjacent the distal end face 18 of the wheel stud 12 is wide enough to receive the distal cap 26 of the locking pin 24 freely. A remainder of the axial bore 16 is narrower, but is still dimensioned to receive a remainder of the locking pin 24, including its proximal end section 30, freely. The axial bore 16 as a whole is long enough to receive the entire locking pin 24. A coil spring 32 is located within the wider portion 31 of the axial bore 16, surrounding the spring support portion 27 of the locking pin 24. The coil spring 32 is retained between the distal cap 26 of the locking pin 24 and a proximal end of the wider portion 31 of the axial bore 16.

Thus, in Figure 7, the distal cap 26 of the locking pin 24 projects outwardly from the distal end face 18 of the wheel stud 12, and the proximal end section 30 is spaced from a proximal end of the axial bore 16.

In Figure 8, the distal cap 26 of the locking pin 24 is disposed within the wider portion 31 of the axial bore 16, with the distal end face 25 of the locking pin 24 flush with the distal end face 18 of the wheel stud 12. The proximal end section 30 of the locking pin 24 is now close to the proximal end of the axial bore 16.

Due to the distal cap 26 filling part of the wider portion 31 of the axial bore 16, the coil spring 32 is significantly more compressed in the configuration of Figure 8, relative to the configuration of Figure 7. Thus, when the locking pin 24 is in the disposition of Figure 8, the coil spring 32 is urging the locking pin 24 outwardly from the axial bore 16, towards the disposition of Figure 7.

We now come to the core of the locking arrangement between the wheel nut 17 and the wheel stud 12.

As is illustrated in Figures 7 and 8, the lateral bore 19 extends between the axial bore 16 and the threaded outer surface 15 of the wheel stud 12. Within the lateral bore 19 are retained a first and a second ball-bearing 33,34, which between them comprise a locking element of the arrangement of the present invention. It should be noted that the lateral bore 19 is too short to hold both ball-bearings 33,34 at the same time, and a portion of the second ball-bearing 34 at least must therefore project from an end of the lateral bore 19. (Suitably-sized single-piece locking elements may be used in other versions of the invention, but it is currently preferred to use a pair of ballbearings 33,34, sized to be able to travel and turn freely within the lateral bore 19).

In the configuration of Figure 8, with the locking pin 24 disposed within the axial bore 16, the lateral bore 19 is aligned with one of the grooves 28a, 28b. The first of the ball-bearings 33 may thus project from the lateral bore 19 into the axial bore 16 and thus be received into the groove 28a, 28b. The depth of the grooves 28a, 28b, the length of the lateral bore 19 and the diameters of the ball-bearings 33,34 are selected such that this leaves sufficient space within the lateral bore 19 to accommodate an whole of the second ball-bearing 34.

This leaves the wheel nut 17 free to turn and move along the threaded surface 15 of the wheel stud.

In the configuration of Figure 7, on the other hand, the locking pin 24 is displaced slightly outwardly from the axial bore 16, such that the lateral bore 19 is aligned instead with the intermediate platform 29 of the locking pin 24. Since the intermediate platform 29 is not cut as deeply into the locking pin 24 as are the grooves 28a, 28b, the adjacent first ball-bearing 33 cannot project as far into the axial bore 16 as it does in Figure 8. Thus, there is insufficient space within the lateral bore 19 to accommodate the whole of the second ball-bearing 34, which must therefore project from the outer end of the lateral bore 19, proud of the threaded surface 15 of the wheel stud 12.

With the wheel nut 17 threaded on to the wheel stud 12, this is only possible when the elongate recess 23 in the threaded surface of the wheel nut 17 is aligned with the lateral bore 19. The elongate recess 23 may thus receive a portion of the ballbearing 34 projecting from the lateral bore 19.

The elongate recess 23 extends longitudinally of the wheel nut 17 so that it may align with the lateral bore 19 over a significant range of locations of the wheel nut 17 along the threaded surface 15 of the wheel stud 12. However, as shown in Figure 3, the elongate recess 23 is relatively narrow. Thus, the portion of the second ball-bearing 34 that projects into the elongate recess 23 prevents rotational movement of the wheel nut 17 on the threaded portion 15 with which it is engaged.

The configuration of Figure 7 thus represents a locked configuration in which the wheel nut 17 is restrained from turning on the threaded portion 15 of the wheel stud 12 and further movement of the wheel nut 17 along the wheel stud 12 is thus prevented. The configuration of Figure 8 is then an unlocked configuration, in which the wheel nut 17 is free to turn and to move along the wheel stud 12.

As noted above, the coil spring 32 is urging the locking pin 24 to move outwardly from the axial bore 16. However, in the unlocked configuration of Figure 8 this is not possible. The lateral bore 19 is not currently aligned with the elongate recess 23 of the wheel nut 17, so to accommodate the whole of the second ball-bearing 34 within the lateral bore 19, the first ball-bearing 33 must project into the axial bore 16 and be received in one of the grooves 28a, 28b. The intermediate platform 29, being shallower than the grooves 28a, 28b, comes into contact with the first ball-bearing 33 and prevents outwards motion of the locking pin 24.

However, if the wheel nut 17 then travels along the wheel stud 12 far enough for the elongate recess 23 to come into alignment with the lateral bore 19, this changes. The coil spring 32, urging the locking pin 24 outwardly of the axial bore 16, causes an edge of the intermediate platform 29 to bear on the first ball-bearing 33 (at this stage partially received into the groove 28b). Since the second ball-bearing 33 is now free to travel outwardly from the lateral bore 19 into the elongate recess 23, the first ballbearing 33 can be deflected upwardly from the groove 28b into the lateral bore 19. The locking pin 24 is now free to move into the disposition shown in Figure 7, with the first ball-bearing 33 held on the intermediate platform 29. The second ballbearing 34, projecting into the elongate recess 23, locks the wheel nut 17 against turning and moving any further along the wheel stud 12.

This mechanism effectively intercepts a wheel nut 17 that has come loose and is moving along the wheel stud 12, and automatically locks the wheel nut 17 in place, resisting further motion.

Additionally, when the mechanism has engaged in this way with a loosening wheel nut 17 that is migrating along the wheel stud 12, the distal cap 26 of the locking pin 24 will then stand proud of the distal end face 18 of the wheel stud 12. This provides a clear visual indication to a user checking the vehicle's wheels 4 that there is an issue with that wheel nut 17, and that all of the wheel nuts 17 on that wheel 4 should probably be checked and tightened where necessary.

Figures 9 and 10 show in more detail the interaction of the grooves 28a, 28b, the intermediate platform 29 and the first ball-bearing 33.

Figure 9 corresponds to the unlocked configuration shown in Figure 8. Conveniently, the locking pin 24 from the spring support section 27 to the proximal end section 30 is manufactured from a cylindrical body of constant diameter. The two parallel longitudinal grooves 28a, 28b are then each machined into this cylindrical body, both grooves 28a, 28b having a part-cylindrical profile, sized for the first ball-bearing 33 to fit accurately within either of the grooves 28a, 28b. This precise location of the first ball-bearing 33 in the groove 28b allows the second ball-bearing 34 within the lateral bore 19 to sit just within the lateral bore 19 without projecting outwardly.

Figure 10 corresponds to the locked configuration from Figure 7. The intermediate platform 29 is also machined into the cylindrical body of the locking pin 24, also with a part-cylindrical profile sized for the first ball-bearing 33 to fit accurately. However, the intermediate platform 29 is significantly shallower than the grooves 28a, 28b. This produces a significantly raised location for the first ball-bearing 33, such that the second ball-bearing 34 is displaced to project from the lateral bore 19 into the elongate recess 23 in the wheel nut 17.

As is also visible in Figures 9 and 10, the proximal end section 30 remains proud once the grooves 28a, 28b and the intermediate platform 29 have been machined into the cylindrical body of the locking pin 24. The proximal end section 30 thus contacts the first ball-bearing 33 and prevents the locking pin 24 from moving any further outwardly from the wheel stud 12 than in Figure 7.

Figure 11 , viewed in conjunction with the remaining Figures, helps to illustrate how a user may manually lock and unlock the wheel stud 12 and wheel nut 17 combination.

The first ball-bearing 33 is shown in three alternative positions: on the intermediate platform 2,9 or within either of the grooves 28a, 28b (note: the first ball-bearing 33 is shown undersized in this schematic view for clarity).

In Figure 4, the locking pin 24 is shown aligned such that the arrow symbol on its distal end face 25 points to a “locked” symbol on the distal end face 18 of the wheel stud 12. This corresponds also to the alignment of the locking pin 24 shown in Figures 9 and 10. The first ball-bearing 33 sits conformably in groove 28b, as in Figure 8, but is ready to move up and on to the intermediate platform 29, if the wheel nut 17 and its elongate recess 23 come into alignment with the lateral bore 19, thus leading to the locked configuration of Figure 7.

However, a user needs to be able to fit the wheel nut 17 on to the wheel stud 12 in the first place without this locking arrangement engaging. Furthermore, once the locking arrangement has engaged, it must be possible for the user to disengage it at will, so that the wheel nut 17 can be re-tightened to grip the hub portion 5 of the wheel 1 .

The user may therefore manually press on the distal end face 25 of the locking pin 24, pushing the locking pin 24 inwardly into the axial bore 16, against the outwardly urge from the coil spring 32.

Where the first ball-bearing 33 is already on the intermediate platform 29 in the locked configuration, moving the locking pin 24 inwardly in this way drops the first ball-bearing 33 back into the groove 28b, and the second ball-bearing 34 is no longer held in a position projecting into the elongate recess 23. The wheel nut 17 is now free to be turned - even if the second ball-bearing 34 still remains projecting out of the lateral bore 19, rotation of the wheel nut 17 will push it down into the lateral bore 19, which now has room to accommodate it.

To prevent the locking arrangement from operating again until needed, the user may then twist the locking pin 24 clockwise until the arrow symbol on the distal end face 25 of the locking pin 24 points to an “unlocked” symbol on the distal end face 18 of the wheel stud 12, again most clearly shown in Figure 4.

This clockwise twist of the locking pin 24 effectively moves the first ball-bearing 33 into the other groove 28a (see the chain of arrows 35 in Figure 11). Releasing the locking pin 24 at this stage allows the coil spring 32 to push the locking pin 24 back outwardly, with the result that the first ball-bearing 33 effectively moves to a proximal end of this groove 28a. Owing to the depth of this groove 28a, this first ball-bearing 33 still projects far enough into the axial bore 16 that the second ball bearing 34 remains completely within the lateral bore 19. The wheel nut 17 thus remains free to turn. From this position, the ball bearing cannot move directly on to the intermediate platform 29 and the locking arrangement does not engage, even if the elongate recess 23 aligns with the lateral bore 19. The wheel nut 17 can thus be tightened without hindrance.

To prime the locking arrangement, all the user has to do is to push the locking pin 24 inwardly once more, twist it anti-clockwise until the arrow points to the “locked” symbol, and then release it. This effectively moves the first ball-bearing 33 into the groove 28b, with the locking arrangement still unlocked but ready. Then, as described above, as soon as the wheel nut 17 moves such that the elongate recess 23 is aligned with the lateral bore 19, the first ball-bearing 33 can move on to the intermediate platform 29, displace the second ball-bearing 34 outwardly from the lateral bore 19, and thus automatically engage the locking arrangement.

Claims

CLAIMS:

1. Fastening apparatus for securing a vehicle wheel to a respective hub mounting, comprising: a plurality of threaded stud means extending from the hub mounting and so disposed that the vehicle wheel is locatable on the hub mounting with each said stud means extending through a corresponding aperture in the vehicle wheel, and a plurality of wheel nut means threaded to engage with respective said stud means, so as to hold the vehicle wheel securely to the hub mounting; wherein an axial bore extends longitudinally into each said stud means from a distal end thereof, and a radial bore extends inwardly from a threaded surface of each said stud means to intersect with said axial bore; and wherein each said stud means comprises: an elongate locking pin longitudinally moveable within said axial bore, and a lateral locking element radially moveable within said radial bore; and wherein: each said locking pin is provided with first recess means adapted to receive a respective first end of the lateral locking element; and each said wheel nut means is provided with second recess means adapted to receive a respective second end of the lateral locking element; and each said locking pin being moveable between a first disposition in which its first recess means is aligned with the radial bore, the first end of the lateral locking element is located within the first recess means, and the second end of the lateral locking element is located within the radial bore, and a second disposition in which said first recess means is not aligned with the radial bore, the first end of the lateral locking element is displaced in the direction of the lateral bore, and the second end of the lateral locking element extends outwardly from the radial bore into the second recess means of the wheel nut means.

2. Fastening apparatus as claimed in Claim 1 , wherein the locking pin is biased towards said second disposition.

3. Fastening apparatus as claimed in Claim 2, wherein in said second disposition of the locking pin, the second end of the lateral locking element, extending into the second recess means of the wheel nut means, prevents the wheel nut means from rotating in engagement with the threaded surface of the respective stud means.

4. Fastening apparatus as claimed in Claim 2 or Claim 3, wherein in said first disposition of the locking pin, the second end of the lateral locking element, being disposed within the radial bore and outside the second recess means, allows the wheel nut means to be rotated in engagement with and along the threaded surface of the stud means, so as to fasten or unfasten the wheel nut means.

5. Fastening apparatus as claimed in any one of the preceding claims, wherein the lateral locking element comprises a plurality of separate spherical bodies located within the radial bore.

6. Fastening apparatus as claimed in Claim 5, wherein the lateral locking element comprises two said spherical bodies.

7. Fastening apparatus as claimed in Claim 6, wherein said two spherical bodies comprise the respective first and second ends of the lateral locking element.

8. Fastening apparatus as claimed in any one of the preceding claims, wherein said first recess means comprises an elongate channel extending longitudinally of the locking pin.

9. Fastening apparatus as claimed in Claim 8, wherein the locking pin is further provided with third recess means, also adapted to receive the first end of the lateral locking element, and comprising an elongate channel extending longitudinally of the locking pin, adjacent the first recess means and parallelly thereto.

10. Fastening apparatus as claimed in Claim 9, wherein the first and third recess means are connected adjacent a respective end of each, optionally adjacent a distal end of each.

11. Fastening apparatus as claimed in any one of the preceding claims, wherein the locking pin is provided with fourth recess means disposed adjacent an end of the first recess means, also adapted to receive the first end of the lateral locking element, wherein the fourth recess means has a depth substantially less than a depth of the first recess means.

12. Fastening apparatus as claimed in Claim 11 , wherein when the first end of the lateral locking element is received in the fourth recess means, the second end of the lateral locking element extends outwardly from the radial bore and into the second recess means of the wheel nut means.

13. Fastening apparatus as claimed any one of the preceding claims, wherein said second recess means comprises an elongate recess.

14. A wheel nut for securing a vehicle wheel to a respective hub mounting, comprising wheel nut means threaded to engage with respective threaded stud means, so as to hold the vehicle wheel securely to the hub mounting; wherein a thread-bearing surface of the wheel nut means is provided with recess means extending transversely to its thread.

15. A wheel nut as claimed in Claim 14, wherein said recess means comprises an elongate recess.

16. A wheel nut as claimed in Claim 15, wherein said elongate recess extends substantially orthogonally to a direction of the threads of said threaded surface.

17. A wheel nut as claimed in any one of Claims 14 to 16, wherein the elongate recess is deeper than the threads of said threaded surface.

18. A wheel stud for securing a vehicle wheel to a respective hub mounting, comprising: a threaded stud means fixedly mountable to the hub mounting and threaded for a wheel nut to engage therewith; wherein an axial bore extends longitudinally into said stud means from a distal end thereof, and a radial bore extends inwardly from a threaded surface of said stud means to intersect with said axial bore; and wherein the stud means comprises: an elongate locking pin longitudinally moveable within said axial bore, and a lateral locking element radially moveable within said radial bore; and wherein: said locking pin is provided with first recess means adapted to receive a first end of the lateral locking element; said locking pin being moveable between: a first disposition in which its first recess means is aligned with the radial bore, the first end of the lateral locking element is located within the first recess means, and a remote second end of the lateral locking element is located within the radial bore, and a second disposition in which said first recess means is not aligned with the radial bore, the first end of the lateral locking element is displaced in the direction of the radial bore, and the second end of the lateral locking element extends outwardly from the radial bore.

19. A wheel stud as claimed in Claim 18, wherein the locking pin is biased towards said second disposition.

20. A wheel stud as claimed in Claim 18 or Claim 19, wherein the lateral locking element comprises a plurality of separate spherical bodies located within the radial bore.

21. A wheel stud as claimed in Claim 20, wherein the lateral locking element comprises two said spherical bodies.

22. A wheel stud as claimed in Claim 21 , wherein said two spherical bodies comprise the respective first and second ends of the lateral locking element.

23. A wheel stud as claimed in any one of Claims 18 to 22, wherein said first recess means comprises an elongate channel extending longitudinally of the locking pin.

24. A wheel stud as claimed in Claim 27, wherein the locking pin is further provided with third recess means, also adapted to receive the first end of the lateral locking element, and comprising an elongate channel extending longitudinally of the locking pin, adjacent the first recess means and extending parallelly thereto.

25. A wheel stud as claimed in Claim 24, wherein the first and third recess means are connected adjacent a respective end of each, optionally a distal end of each.

26. A wheel stud as claimed in any one of Claims 18 to 25, wherein the locking pin is provided with fourth recess means disposed adjacent an end of the first recess means, also adapted to receive the first end of the lateral locking element, the fourth recess means having a depth substantially less than a depth of the first recess means.

27. A wheel stud as claimed in Claim 26, wherein when the first end of the lateral locking element is received in the fourth recess means, the lateral locking element extends less far into the axial bore than it does when received in the first recess means.

28. A wheel stud as claimed in Claim 27, wherein the second end of the lateral locking element then extends outwardly from the radial bore and into the second recess means of the wheel nut means.

29. A hub mounting adapted for a vehicle wheel to be secured thereto, comprising: a plurality of threaded stud means as claimed in any one of Claims 18 to 28, so mounted as to extend from the hub mounting and so disposed that the vehicle wheel is locatable on the hub mounting with each said stud means extending through a corresponding aperture in the vehicle wheel.

30. A hub mounting as claimed in Claim 29, provided with a plurality of wheel nuts as claimed in any one of Claims 14 to 17, each adapted to engage with a respective threaded stud means.

31. A method for securing a wheel to a vehicle, comprising the steps of: providing fastening apparatus for securing a vehicle wheel to a respective hub mounting, as disclosed in any one of Claim 1 to 13; mounting the threaded stud means thereof to a hub mounting of the vehicle; locating a wheel on the hub mounting with each threaded stud means extending through a respective aperture in a hub portion of the wheel; threading each wheel nut means of the fastening apparatus engagingly on to a respective threaded stud means; and tightening each wheel nut means into contact with the hub portion of the wheel so as to hold the wheel securely between the wheel nut means and the hub mounting.