GB2401159A

GB2401159A - A device for locking a nut on a threaded stud

Info

Publication number: GB2401159A
Application number: GB0310043A
Authority: GB
Inventors: Jason C Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-05-01
Filing date: 2003-05-01
Publication date: 2004-11-03

Abstract

A device for locking two proximal wheel nuts comprises a base plate 20 having a coupling flange 22, and a connection plate 40, carrying a pair of independently rotatable washers 30, 31. The washers each have a central hexagonal aperture, which corresponds with the hexagonal profile of the nut, and the connection plate has two corresponding oversized apertures, which allow the nut to turn freely. The base plate is fitted over threaded studs 12 and 14 and the nuts are fitted such that they retain the base plate in position. The connection plate and washers are then fitted to the nuts, as shown in the diagram. Ratchet teeth and grooves disposed on the mating surfaces of the connection plate and washer enable the nuts to be tightened but prevent the nut from working loose. The connection plate is joined to the base plate at the flange 22 using a split pin (not shown).

Description

24011 59

A DEVICE FOR LOCKING A NUT ON A THREADED STUD

This invention relates to a device for locking a nut on a threaded stud. It is particularly applicable, but by no means limited, to locking vehicle wheel nuts, in particular those of heavy commercial vehicles.

Background to the Invention

In many circumstances a nut may be prone to become loosened from a studded thread or bolt. Typically, a nut is prone to unwind from its thread if there is a loss of tension in the stud/nut assembly. Furthermore, the likelihood of a nut unwinding from its stud may be increased if the nut and stud are part of a vibrating object, such as a piece of machinery, in particular a vehicle.

With vehicles, and heavy commercial vehicles in particular, the problem of wheel nuts becoming loose is particularly serious. A number of people are killed each year after being struck by a detached lorry wheel moving at speed, the wheel having become separated from the vehicle after its wheel nuts becoming loose. It is likely that some non-fatal injuries also occur every year for the same reason. Even if the wheel does not actually detach, considerable and expensive damage may be caused to the wheel and its studs following loosening of the nuts.

For vehicle wheels, indicator devices which attach around vehicle wheel nuts are known.

These indicator devices comprise a pointing part which is attached to the nut, and the device rotates with the nut should the nut unwind. Such indicator devices only provide a visual indication as to whether the nut has started to become unwound, and require regular checking. They cannot themselves prevent the wheel nut from becoming undone. Various devices and methods are known for preventing a nut from turning on a stud. However, none of these methods and devices enable the nut to be tightened, or its tightness checked, without removing or dismantling the device.

Accordingly, it is a general object of the present invention to provide a device for locking a nut on a threaded stud that overcomes or at least mitigates at least some of the problems and disadvantages identified above.

Summary of the Invention

According to a first aspect of the invention there is provided a device for locking a nut on a threaded stud, said device comprising: a first member adapted to be mounted in a fixed position with respect to the nut; a second member having an open region corresponding in shape to the profile of the nut when viewed along the axis of the stud, the second member being arranged such that, in use, the nut fits securely within the open region such that the nut cannot turn independently of the second member; and means for coupling the second member to the first member, thereby locking the nut in a fixed position in use. The device advantageously prevents the nut from loosening, and does not require periodic checking.

The term "threaded stud" as used herein should be interpreted broadly to encompass bolts and other types of threaded fastener onto which a nut may be attached.

Preferably the first member is adapted to locate around the stud. l (

Particularly preferably the first member incorporates two apertures arranged such that, in use, the first member locates around two studs, the two studs being in fixed mutually proximal positions. By locating around two studs the first member is secured in position and is prevented from rotating. The first member may be adapted to be fastened in place by the application of one or more nuts to one or more of the studs.

Preferably the first member further comprises an anchoring portion extending substantially parallel to the axis of the stud, onto which anchoring portion the second member is coupled.

Preferably the second member comprises an aperture corresponding substantially in shape to the profile of the nut when viewed along the axis of the stud. That is to say, the second member passes entirely around the nut in use.

Preferably the means for coupling the second member to the first member comprises a third member, the third member comprising means for engaging the third member with the first member, and means for engaging the third member with the second member. The third member may include an aperture arranged to locate around a nut, such that the nut can turn independently of the third member.

Particularly preferably the second and third members incorporate a ratchet mechanism acting between the second member and the third member, the ratchet mechanism enabling the nut and the second member to turn in only one direction of rotation with respect to the third member. This ratchet mechanism provides the advantage that the nut may be tightened if necessary, without having to undo or remove the device of the present invention.

( ( r ( ( l Preferably the third member comprises one or more ratchet teeth and the second member comprises a plurality of holes or recesses disposed around the open region, the holes being arranged to receive the one or more ratchet teeth. The term "hole" as used herein should be interpreted broadly to cover any aperture, indentation or recess operable to receive a ratchet tooth. Alternatively the second member may comprise one or more ratchet teeth disposed around the open region and the third member may comprise a plurality of holes or recesses, the holes being arranged to receive the one or more ratchet teeth. The plurality of holes is preferably sufficiently great in number that the device is able to lock the nut effectively, irrespective of its rotational position with respect to the stud.

Preferably the third member is arranged to couple two second members to a first member.

In such a case, the two second members on which the third member acts preferably act around the nuts of the two studs around which the first member locates.

Preferably the third member comprises one or more portions shaped and configured to support the second member. This advantageously enables the second member to be held in an optimum position relative to the height of the nut.

Preferably the means for engaging the third member with the first member comprises an aperture through which the anchoring portion securely locates. The anchoring portion may be secured using a split pin arrangement.

In a preferred embodiment of the invention the device is adapted for locking vehicle wheel nuts. r r '

r ( , , According to a second aspect of the invention a vehicle wheel is provided having a locking device according to the first aspect of the invention.

Brief Description of the Drawings

S An embodiment of the invention will now be described, by way of example, and with reference to the drawings in which: Figure 1 illustrates a side view of the locking device in use, locking two nuts; Figure 2a illustrates a plan view of the base plate component, before being bent into shape; Figure 2b illustrates a side view of part of the base plate, when bent into shape during I O manufacture; Figure 3 illustrates a plan view and corresponding side view of the locking washer component; Figure 4a illustrates a plan view of the locking plate component, before being bent into shape; Figure 4b illustrates a side view of the locking plate component; Figure 4c illustrates a close up side view of a ratchet tooth of the locking plate; Figure 5a illustrates a plan view of the locking device once assembled and in use; Figure 5b illustrates a side view of the locking device in use; Figures 6a and 6b show the drawings of Figures 2a and 2b with example dimensions in millimetres; Figure 7 shows the drawing of Figure 3 with example dimensions in millimetres; and Figures 8a, 8b and 8c show the drawings of Figures 4a, 4b and 4c with example dimensions in millimetres.

Consistent numbering of equivalent components is used throughout the drawings. is

i c r I r r r r r f r r r r r I À r r r r (

Detailed Description of Preferred Embodiments

The present embodiments represent the best ways known to the applicant of putting the invention into practice. However they are not the only ways in which this can be achieved.

The embodiment described below relates to the use of the Invention in locking vehicle wheel nuts. It will be appreciated by those skilled in the art that the invention may readily be applied to the locking of nuts in other applications, for example, on pieces of industrial machinery.

Overview Figure 1 illustrates the locking device 10 installed in use. The device 10 acts around two studs 12, 14, the studs being in fixed positions in the hub of a vehicle wheel. Each stud is fitted with a wheel nut 16, 18. The locking device prevents the wheel nuts 16, 18 from unwinding should there be a loss of tension in the wheel stud/nut assembly.

The locking device 10 of Figure 1 comprises four principal components: The first is a base plate 20 (shown separately in Figure 2a) located around the two studs 12, 14. The studs 12, 14 pass through apertures in the base plate 20, and the nuts 16, 18 themselves hold the base plate in a fixed position. Since two studs 12, 14 pass through the device, it is prevented from rotating relative to the wheel. The base plate 20 comprises an integral anchoring portion 22 which extends substantially parallel to the studs 12, 14.

A lock washer 30, 31 (shown separately in Figure 3) is located around each nut 16, 18.

Each nut 16, 18 passes through an aperture in each lock washer 30, 31, the shape of each r I I ( r r ( aperture being substantially that of the nut such that the nut cannot turn independently of the lock washer. In this example the aperture in each lock washer 30, 31 is hexagonal, to fit snugly around each of the two hexagonal nuts 16, 18.

Spanning the two lock washers 30, 31 is a locking plate 40 (shown separately in Figure 4a) which acts on the lock washers 30, 31 to prevent them from turning so as to undo the nuts 16, 18 from the studs 12, 14. The locking plate 40 includes two circular apertures to enable it to pass around the nuts 16, 18. The shape of these apertures is such that the nuts are not prevented from rotating therein. A ratchet mechanism exists between each lock washer 30, 31 and the locking plate 40. The ratchet mechanism prevents each nut from undoing, but does allow each nut to be tightened as required. The locking plate 40 is fastened to the anchoring portion 22, thereby preventing the locking plate from becoming detached from the nuts.

The base plate 20 The base plate 20 is fabricated from stainless steel 2 mm thick. Figure 2a shows the base plate as cut from a piece of steel sheet. The base plate 20 includes two apertures 27, 28 shaped and sized to allow a stud to pass through each one. Regions 22 and 24 are bent through 90 , as shown in Figure 2b, to form anchor portions perpendicular to the part of the base plate containing the apertures. Each anchor portion 22, 24 is provided with a hole 21, 26 (to receive a split pin in use) and a detent tooth 23, 25. Each detent tooth 23, 25 is formed by punching the steel sheet and bending the tooth out, as shown in an enlarged form in Figure 2b.

NI ( r À À Figures 6a and 6b show the drawings of Figures 2a and 2b with example dimensions given in millimetres.

The lock washer 30 The lock washer 30, as shown in Figure 3, is also fabricated from stainless steel 2 mm thick.

The lock washer 30 includes a central hexagonal aperture (shaped to correspond with the profile of the nut) and a plurality (in this case 24) equally spaced holes 34 around the perimeter of the washer 30. These holes 34 form part of the ratchet mechanism with the locking plate 40.

As mentioned above, the holes could be recesses or indentations rather than through-holes per se. Each hole may be formed by punching out on all sides of the hole, so that the punched-out material falls away. Alternatively each hole may be punched out on fewer than all its sides, thereby forming a tab that is bent away from the plane of the lock washer to form the hole.

Figure 7 shows the drawings of Figure 3 with example dimensions given in millimetres.

The locking plate 40 The locking plate 40 is fabricated from stainless steel 1.5 mm thick. Figure 4a shows the locking plate as cut from a piece of steel sheet. The locking plate 40 includes two circular apertures 42, 43 sufficiently large to enable a nut to rotate freely therein. Around each aperture 42, 43 a plurality (in this case 24) of equally spaced ratchet teeth 47 are formed in the sheet steel by punching out some sides of the tooth and then bending the material into shape (as shown in close up in Figure 4c). These teeth 47 are shaped and positioned to I I r r I r À r engage with the corresponding holes 34 provided in each lock washer 30, 31. It will be appreciated that, for the ratchet mechanism to function satisfactorily, it is not necessary for every hole 34 to have a corresponding ratchet tooth 47.

In an alternative embodiment the ratchet teeth may be provided around each lock washer and the corresponding holes may be provided in the locking plate.

The ratchet mechanism described above is only one of a wide range of possible ratchet mechanisms that could be employed in this context. A variety of ratchet assemblies are known in the prior art and could be used in the context of this invention, if necessary making design modifications or adaptations as would be readily appreciated by those skilled in the art. This disclosure is intended to encompass all known ratchet mechanisms, and those yet to be discovered, when used in this context. For example, one or more radially-extending ratchet teeth or arms, and corresponding holes or recesses, may be employed.

The locking plate 40 also comprises a number of tabs 46a - 46f, which are bent as shown in Figure 4b to form members for retaining and supporting the lock washers 30, 31 (as shown assembled in Figures 1 and 5b).

Also provided in the locking plate 40 are a pair of slots 44, 45 configured to engage with the anchor portions 22, 24 of the base plate 20.

figures 8a, 8b and 8c show the drawings of Figures 4a, 4b and 4c with example dimensions given in millimetres.

r À ( r r À ' ' r ( Assembly of the locking device The base plate 20 is first placed over two wheel studs 12, 14 and the wheel nuts 16, 18 are tightened down onto it. The two lock washers 30, 31 are then installed in the locking plate 40, such that they are retained and supported by the tabs 46a - 46f and the ratchet mechanism is operational. The locking plate 40 (containing the lock washers 30, 31) is then fitted over the nuts 16, 18, such that each nut engages in the correspondingly-shaped aperture 32 in each of the two lock washers 30, 31. Sufficient ratchet holes 34 are provided in the lock washers to enable each lock washer to be rotated to align with the rotational position of the corresponding nut. The locking plate 40 is fitted over the anchor portions 22, 24 of the base plate such that the anchor portions pass through the slots 44, 45 in the locking plate. In doing so, the detent teeth 23, 25 spring into position as shown in Figure 5b, preventing the inadvertent subsequent removal of the locking plate 40 from the base plate 20.

As shown in Figure 5a, a split pin 50 may be fastened through the holes 21, 26 in the anchor portions to further secure the locking plate 40 in place.

The locking device in use The ratchet system prevents the wheel nuts from vibrating loose should there be a loss of tension in the wheel nuVstud assembly. Highly advantageously, the ratchet mechanism also allows the for the independent re-tensioning (re-torquing) of each wheel nut without disassembly of the locking device, thus encouraging regular re-tensioning of the wheel nuts.

Although the device cannot prevent some loss of tension in the wheel nuVstud assembly, by preventing the nut from unwinding the device does ensure that there can never be sufficient r r r À cr rotational movement of the nut to allow the wheel to become damaged. Moreover, the nut can never become undone to the extent that the wheel becomes detached from the vehicle.

On a vehicle, in particular a heavy commercial one, the locking device is preferably fitted to all the wheel nuts of the road wheels, or to as many pairs of wheel nuts as possible.

Altemative applications for the locking device The locking device is applicable to many situations other than vehicle wheels. For example, the device may be use to lock nuts on threaded studs in industrial machinery, particular in cases where the machinery produces (or is susceptible to) vibrations that could cause the nuts to come undone. The inadvertent unwinding of nuts on such machinery in use could cause costly damage to the machinery and may also give rise to an accident.

It will also be appreciated that, while this description has been in terms of a nut fitting onto a threaded stud, the present invention applies equally well to the arrangement of a bolt fixed into a threaded hole or bore. Thus, in the description above and the claims which follow the terms 'nut' and 'bolt' may be used interchangeably as may the terms 'stud' or 'threaded bore', as the context allows.

Claims

À À r, r r r r I r r r r CLAIMS

1. A device for locking a nut on a threaded stud, said device comprising: a first member adapted to be mounted in a fixed position with respect to the nut; a second member having an open region corresponding in shape to the profile of the nut when viewed along the axis of the stud, the second member being arranged such that, in use, the nut fits securely within the open region such that the nut cannot turn independently of the second member; and means for coupling the second member to the first member, thereby locking the nut in a fixed position in use.

2. A device as claimed in Claim 1, wherein the first member is adapted to locate around the stud.

3. A device as claimed in Claim 1 or Claim 2, wherein the first member incorporates two apertures arranged such that, in use, the first member locates around two studs, the two studs being in fixed mutually proximal positions.

4. A device as claimed in any preceding claim, wherein the first member is adapted to be fastened in place by the application of one or more nuts to one or more of the studs.

- r r r r À À r À r t I r rr r r

5. A device as claimed in any preceding claim, wherein the first member further comprises an anchoring portion extending substantially parallel to the axis of the stud, onto which anchoring portion the second member is coupled.

6. A device as claimed in any preceding claim, wherein the second member includes an aperture corresponding substantially in shape to the profile of the nut when viewed along the axis of the stud.

7. A device as claimed in any preceding claim, wherein the means for coupling the second member to the first member comprises a third member, the third member comprising means for engaging the third member with the first member, and means for engaging the third member with the second member.

8. A device as claimed in Claim 7, wherein the third member includes an aperture arranged to locate around a nut, such that the nut can turn independently of the third member.

9. A device as claimed in Claim 7 or Claim 8, wherein the second and third members incorporate a ratchet mechanism acting between the second member and the third member, the ratchet mechanism enabling the nut and the second member to turn in only one direction of rotation with respect to the third member.

10. A device as claimed in Claim 9, wherein the third member comprises one or more ratchet teeth and the second member comprises a plurality of holes or recesses r r À, t ( r t disposed around the open region, the holes being arranged to receive the one or more ratchet teeth.

11. A device as claimed in Claim 9, wherein the second member comprises one or more ratchet teeth disposed around the open region and the third member comprises a plurality of holes or recesses, the holes being arranged to receive the one or more ratchet teeth.

12. A device as claimed in any of Claims 7 to 11, wherein the third member is arranged to couple two second members to a first member.

13. A device as claimed in any of Claims 7 to 12, wherein the third member comprises one or more portions shaped and configured to support the second member.

14. A device as claimed in any of Claims 7 to 13 when dependent on Claim 5, wherein the means for engaging the third member with the first member comprises an aperture through which the anchoring portion securely locates.

15. A device as claimed in any preceding claim adapted for locking vehicle wheel nuts.

16. A vehicle wheel provided with a device as claimed in Claim 15.

17. A device substantially as herein described with reference to and as illustrated in any combination of the accompanying drawings.