Technical field The present invention relates to a screw device and an assembly for theft-proofing, which make undue thefts of vehicle wheels more difficult. The invention further relates to a motor vehicle with vehicle wheels which have been theft-proofed by means of the screw device being part of the assembly.

The invention can be applied for all types of vehicle wheels, and particularly advantageously when exclusive private cars provided with special rims or the like are concerned.

Background of the invention Recently, it has become more and more common with car thefts and other undue thefts such as, for example, thefts of vehicle wheels from unattended motor vehicles. Since vehicle wheels today are expensive, such thefts result in a significant economic loss for the vehicle owner, in particular if the motor vehicle is provided with exclusive wheel rims with special design or the like.

Accordingly, it is desirable to make it as difficult as possible for criminals, or persons which otherwise are unable to let things alone, to remove vehicle wheels from an unattended motor vehicle. A number of different devices and assemblies which render undue thefts of vehicle wheels difficult have been suggested previously.

Accordingly, the patent publication US 3,241,408 discloses nuts or screws for retaining vehicle wheels, which are reported to prevent thefts and means for applying or removing such nuts or screws. According to US 3,241,408, a threaded fastener for vehicle wheels

comprises means which are adapted for engagement with a wrench for applying and removing the fastener from a cooperating threaded member. Thereby, the means comprise a frusto-conical body having a relatively flat radial outer face at its small end, and a curvi- linearly extending channel of substantially constant width in the outer face forming a continuous, closed figure substantially devoid of straight line portions and of varying curvature, whereby various portions of the closed figure lie at various distances from the axis of the frusto-conical body. In use, a projecting flange formation of the wrench fits within the channel of the means.

Furthermore, the patent publication GB 2 298 691 A discloses an anti-theft device for mounting an object, preferably a vehicle wheel. According to GB 2 298 691 A, unauthorised release of a bolt or a nut is prevented by a freely rotatable, frusto-conical bush fitted over the head of a fastener. Thereby, a ring fits into an annular groove on the outside surface of the head and engages with a corresponding groove on the inside of the bush when in operation. The head of the fastener has an axially projecting section which has lobes on its outer surface. Release is possible with a hollow key with a cylindrical portion with an inner surface of a corresponding shape to the lobate section of the fastener.

The lobes can be varied in shape so as to ensure that they are individual.

However, it has become evident that previously known devices and assemblies for theft- proofing can be circumvented by criminals or unauthorised persons which otherwise cannot let things alone.

Accordingly, wheel bolts having heads with specially designed lock grooves or the like, intended to receive corresponding proj ecting portions of a special wrench can still in many cases be rotated by means of a slightly to small socket or the like which is punched down or pressed down around the head. Recently, it has happened that special socket wrench sets are offered for sale and used for this purpose by unauthorised persons.

When wheel bolts in which the theft-proofing comprises a rotatable bush enclosing the head of the bolt are concerned, it has been found that unauthorised persons can drill in drills between the bush and the head of the wheel bolt in order to achieve a locking

between these. By means of drilling in two drills on both sides of the longitudinal axis of the wheel bolt, the wheel bolts can subsequently be released, for example by means of a shaft with holes in positions corresponding to the two drills, in spite of the claimed theft- proofing.

Summary of the invention Accordingly, a first object of the present invention is to provide a screw device for theft- proofing vehicle wheels which solves the above-mentioned problem with the previously known technique, and which prevents unauthorised persons from removing one or several vehicle wheels from an unattended motor vehicle on which the vehicle wheels are retained by means of one or several screw devices according to the invention.

In accordance with claim 1, this first object of the invention is achieved by means of the screw device comprising a screw, a sleeve and a lock member, wherein the screw has a head and a threaded portion intended to be screwed into a thread of a wheel hub. Thereby, the threaded portion is intended to be screwed into the thread of the wheel hub via a recess arranged in a central portion of a vehicle wheel. The lock member comprises an endless, smoothly undulating or curved lock groove in its first end, and a coupling portion in its second end for torsionally rigid coupling to the head, wherein the sleeve is designed for being retained between the screw and the lock member after the coupling. Thereby, according to the invention, the dimensions of the sleeve are adapted to the dimensions of the recess, so that regions of the central portion adjacent to the recess substantially entirely and with close fitting come to encompass a circumference of the sleeve when the threaded portion has been screwed into the thread.

A second object of the invention is to provide an assembly for theft-proofing vehicle wheels which utilises the screw device according to the invention.

In accordance with claim 11, this second object is achieved by means of the assembly comprising a vehicle wheel in which a central portion forms at least one through-opening, a wheel hub with at least one thread for screwing in or screwing out a threaded portion of a screw, wherein the central portion is designed with a recess encompassing the through-

opening and through which recess the threaded portion is to be screwed into the thread of the wheel hub. The assembly further comprises a key which is intended to turn the screw around its longitudinal axis via a lock member which is coupled to said screw in a torsionally rigid way, wherein the key is designed in order to fit into an endless, smoothly undulating or curved lock groove in a first end of the lock member. The assembly further comprises a sleeve which is retained between the screw and the lock member. According to the invention, the dimensions of the sleeve are adapted to the dimensions of the recess, so that regions of the central portion adjacent to the recess substantially entirely and with close fitting will encompass a circumference of the sleeve when the threaded portion has been screwed into the thread.

A third object of the present invention is to provide a motor vehicle with theft-proofed vehicle wheels.

In accordance with claim 19, this third object of the invention is achieved by means of the motor vehicle comprising a plurality of wheel hubs and at least one vehicle wheel, which is/are mounted to the wheel hub or wheel hubs by means of at least one screw device according to the invention being part of at least one assembly according to the invention.

Brief description of the drawings In the following, the invention will be described with reference to the attached drawings, in which Fig. 1 shows a schematic perspective view of a screw device according to a preferred embodiment of the invention, Fig. 2 shows a schematic sectional view through the central portion of the screw device shown in Fig. 1, Fig. 3 shows a schematic perspective view of the different parts included in the screw device shown in Figures 1 and 2,

Fig. 4 shows a schematic sectional view through an assembly according to a preferred embodiment of the invention, Fig. 5 shows a schematic sectional view through an assembly according to an alternative embodiment of the invention, Figs. 6-8 show three further schematic sectional views through assemblies according to three further alternative embodiments of the invention, Fig. 9 shows a schematic sectional view through an assembly according to a particularly preferred embodiment of the invention.

Detailed description of preferred embodiments In Figures 1-3, different views of a screw device according to a preferred embodiment of the invention are shown. In Fig. 4, the screw device is shown when being part of an assembly according to a preferred embodiment of the invention, while Figs. 5-8 show alternative embodiments of the assembly according to the invention.

The screw device 1; 1'according to the invention and the preferred embodiment comprises a screw 2; 2', a sleeve 3,3'and a lock member 4; 4'. Thereby, the screw 2; 2 has a head 5; 5'and a threaded portion 6; 6'intended to be screwed into a thread 7,7'of a wheel hub 8; 8', wherein the threaded portion 6,6'of the screw 2; 2'is intended to be screwed into the therad 7; 7'of the wheel hub 8; 8'via a recess 14; 14'arranged in a central portion of a vehicle wheel 13; 13'. The lock member 4; 4'comprises an endless, smoothly undulating or curved lock groove 9; 9'in its first end 10; 10'. This design of the lock groove 9; 9' makes it more difficult for an unauthorised person to obtain any stable contact surface inside the lock groove with a tool which is not intended therefore. The shape and other dimensions of the lock groove can of course be varied in a number of different ways within the scope of the invention, as long as the lock groove does not have any edges or sharp notches which could facilitate undue thefts with tools or keys which are not adapted to the lock groove.

The lock member 4; 4'further comprises a coupling portion 11; 11'in its second end 12; 12'for torsionally rigid coupling to the head 5; 5'of the screw 2; 2'. This enables the screw 2; 2'and the lock member 4; 4 to rotate together after coupling, if a sufficient torsional force is applied onto the lock member 4; 4'. Thereby,"torsionally rigid"means that the lock member 4; 4'and the head 5; 5'cannot rotate in relation to each other, but only together with each other.

The above-mentioned sleeve 3; 3'is designed so that it is retained between the screw 2; 2' and the lock member 4; 4'after the coupling, wherein the sleeve in principle is impossible to remove without any special tools or without the screw device being heavily deformed.

According to the invention and the preferred embodiment, the dimensions of the sleeve 3; 3'are adapted to the dimensions of the recess 14; 14', so that regions of the central portion adjacent to the recess 14; 14'substantially entirely and with close fitting will encompass a circumference 15; 15'of the sleeve 3; 3'when the threaded portion 6; 6'has been screwed into the thread 7; 7'. When being used in an assembly according to the invention, screw devices according to the preferred embodiment will make it impossible for an unauthorised person, since there will be no space available for this, to press or punch down an encompassing socket or a similar tool with a slightly smaller inner dimension than the outer dimensions of the sleeve 3; 3'around the sleeve 3; 3'in order to obtain a locking between the sleeve 3; 3'and the lock member 4; 4'.

According to the preferred embodiment of the screw device according to the invention, the sleeve 3; 3'encompasses the first end 10; 10'of the lock member 4; 4'with close fitting.

This makes it more difficult for an unauthorised person to insert a tool which is not intended therefore with the intention of reaching the head 5; 5'of the screw 2; 2'.

Furthermore, according to the preferred embodiment, the sleeve 3; 3'consists of a first material with a high resistance against crack-formation, whereas the first end 10; 10' consists of a second material, wherein the first material is softer than the second material, so that the sleeve 3; 3'can be deformed more easily that the first end 10; 10'when subjected to mechanical damage. This implies that it becomes very difficult for an

unauthorised person to drill in drills or to punch in sharp objects between the sleeve 3; 3' and the lock member 4; 4 with the intention to obtain a stable locking between the sleeve and the lock member, since a drill or a sharp object will slip out into the softer first material of the sleeve so that no stable locking and contact surface can be obtained.

The high resistance against crack formation of the first material also makes it very difficult to break the sleeve without destroying the surrounding and underlying material surfaces. In the preferred embodiment of the invention, the sleeve 3; 3'consists of an aluminium alloy with a high stretchability, whereas the first end 10; 10'is constituted of a steel alloy with a high hardness. However, it is also conceivable with embodiments of the screw device according to the invention with another suitable material choice for the sleeve and the first end.

According to an alternative embodiment of the screw device according to the invention, being part of the assembly shown in Fig. 5, the sleeve 3'comprises a first circumference 16'and a second circumference 15', wherein the first circumference 16'with close fitting encompasses the first end 10'of the lock member 4', and the second circumference 15'is located closer to the screw 2'and is larger than the first circumference 16'. Accordingly, this implies that the sleeve 3'will exhibit a small outer diameter in the outermost end, and a larger outer diameter closest to the surface of the vehicle wheel which the screw device retains. Thereby, the sloping outer walls of the sleeve will make the insertion of objects which are not intended therefore between the sleeve 3'and the lock member 4'difficult, since such objects tend to slip along the sloping sleeve walls without afflicting any damage worth mentioning. Screw devices according to this alternative embodiment are preferably utilised as shown in Fig. 5, where a sleeve 3'with sloping outer walls is cooperating with a recess in a central portion of a vehicle wheel, but can also be utilised for external mounting without cooperating with any recess when they are utilised in an assembly according to the invention.

As is evident from the embodiments of the assembly according to the invention shown in Figs. 6 and 8, the sleeve 3" ; 3""of the screw device can advantageously also comprise a

third circumference 24" ; 24""which is smaller than the second circumference 15" ; 15"".

Amongst other things, this can be advantageous from a weight-saving point of view.

As shown in Figs. 7 and 8, the screw device can also advantageously be designed so that the third circumference 24"', 24""of the sleeve 3"'; 3""encompasses at least a portion of the head 5"'; 5"". This makes it even more difficult for unauthorised persons to be able to reach the head of the screw.

In a particularly advantageous embodiment of the invention, the sleeve 3; 3'is dimensioned so that it can be rotated substantially freely in relation to the lock member 4; 4'and the screw 2; 2'after the coupling. This makes it even more difficult to dislodge the position of a protected screw 5; 5', with a tool which is not intended therefore, in a screw assembly according to the embodiment which is utilised in an assembly according to the invention.

In advantageous embodiments of the screw device according to the invention, as shown in Figs. 1-5, the coupling portion 11; 11'is constituted of a protruding portion which is dimensioned to be pressed into a recess in the head 5; 5'of the screw 2; 2'whe accomplishing the torsionally rigid coupling. However, it is also conceivable with embodiments of the screw device in which the coupling portion comprises a recess in the lock member, and the recess is dimensioned to be pressed over the head of the screw during the torsionally rigid coupling. It is also conceivable with embodiments with another suitable type of coupling between the screw 2; 2'and the lock member 4; 4'. From an economic point of view, it is of course particularly advantageous if the coupling portion 11; 11'is designed to be coupled to wheel screws or wheel bolts with standard dimensions in a torsionally rigid way.

In a particularly advantageous embodiment of the screw device according to the invention, the first end 10; 10'of the lock member 4; 4'comprises a recess 17; 17'for a guiding pin 18 of a key 19, intended to turn the screw 2; 2'around its longitudinal axis 20; 20'via said lock member 4; 4 after insertion into the lock groove 9; 9'. According to this embodiment,

the screw device is designed for facilitating the insertion of a key of an assembly according to the invention.

In the following, a preferred embodiment and a number of advantageous embodiments of an assembly according to the invention will be described with particular reference to Figs.

4 and 5. Thereby, reference is also made to applicable portions of the foregoing description.

According to the invention and the preferred embodiment, the assembly comprises a vehicle wheel 13; 13'in which a central portion forms at least one through-opening 22; 22'.

Thereby, the central portion is usually constituted of a suitably designed rim around which a car tyre is intended to be mounted in order to form the vehicle wheel. However, it is also conceivable with embodiments of the invention in which the central portion is included as a part of a rim, or constitutes a central portion of a vehicle wheel with spokes.

The assembly further comprises a wheel hub 8; 8'with at least one thread 7; 7'for screwing in or screwing out a threaded portion 6; 6'of a screw 2; 2', and a key 19 intended to turn the screw 2; 2'around its longitudinal axis via a lock member 4; 4'which is coupled to said screw 2; 2'in a torsionally rigid way. Thereby, the key 19 is designed for fitting into an endless, smoothly undulating or curved lock groove 9; 9'in a first end 10; 10'of the lock member 4; 4'. As mentioned in the foregoing, this design of the lock groove renders a stable coupling to unauthorised tools or keys difficult.

The assembly further comprises a sleeve 3; 3', which is retained between the screw 2; 2' and the lock member 4; 4'.

In the preferred embodiment of the assembly according to the invention, the central portion is designed with a recess 14; 14'encompassing the through-opening 22; 22'and through which recess 14; 14'the threaded portion 6; 6'is to be screwed into the thread 7; 7'of the wheel hub 8; 8'. Thereby, the dimensions of the sleeve 3; 3'are adapted to the dimensions of the recess 14; 14', so that regions of the central portion adjacent to the recess 14; 14' substantially entirely and with close fitting will encompass a circumference 15; 15'of the

sleeve 3; 3 when the threaded portion 6; 6 has been screwed into the thread 7; 7'. As evident from the foregoing, this prevents unauthorised tools from being pressed or punched down around the sleeve.

According to the preferred embodiment, the sleeve 3; 3'further encompasses the first end 10; 10'of the lock member 4; 4'with close fitting, wherein the sleeve 3; 3'consists of a first material with high resistance against crack-formation, whereas the first end 10; 10' consists of a second material. Thereby, the first material is softer than the second material, so that the sleeve can be deformed more easily than the first end 10; 10'when subjected to mechanical damage.

According to an alternative embodiment of the assembly according to the invention, shown in Fig. 5, the sleeve 3'comprises a first circumference 16'and a second circumference 15', wherein the first circumference 16'with close fitting encompasses the first end 10'of the lock member 4', and the second circumference 15'is located closer to the screw 2'and is larger than the first circumference 16'. As has become evident from the foregoing, this design of the sleeve makes the insertion or drilling-in of an unauthorised tool between the sleeve 3'and the lock member 4'difficult.

As is evident from the embodiments of the assembly according to the invention shown in Figs. 6 and 8, the sleeve 3"; 3""can advantageously also comprise a third circumference 24" ; 24""which is smaller than the second circumference 15" ; 15"". As has become evident from the foregoing, this can be advantageous, amongst other things, from a weight-saving point of view.

As shown in Figs. 7 and 8, the screw device in the assembly can advantageously also be designed so that the third circumference 24"'; 24""of the sleeve 3"'; 3""encompasses at least a portion of the head 5"'; 5"". As has become evident form the foregoing, this makes it even more difficult for unauthorised persons to reach the head of the screw.

According to a particularly preferred embodiment of the assembly according to the invention, the sleeve 3; 3'is dimensioned so that it can be rotated substantially freely in

relation to the lock member 4; 4'and the screw 2; 2'after the torsionally rigid coupling, something which makes it even more difficult for an unauthorised person to influence the screw 2; 2 via the sleeve 3; 3'from the outside.

In another particularly advantageous embodiment of the assembly according to the invention, the first end 10; 10'of the lock member 4; 4'comprises a recess 17; 17'for a guiding pin 18 of the key 19. Thereby, the recess 17; 17'and the guiding pin 18 are arranged and dimensioned so that, when rotating the key 19 around the longitudinal axis 21 of the guiding pin, it is ensured that the key 19 can be fitted into the endless, smoothly undulating or curved lock groove 9; 9'of the lock member 4; 4'. The arrangement with a guiding pin on the key which cooperates with a recess in the lock member enables a user to initially insert only the tip of the guiding pin 18 projecting from the key 19 into the recess 17; 17', in order to subsequently rotate the key 19 until it enters the correct position for enabling a key member 23 of the key to be pressed into the lock groove 9; 9'. In this way, a user having the correct key 19 can obtain a coupling between the key 19 and the lock member 4; 4'without any difficulties.

Furthermore, according to the invention, a preferred embodiment of a motor vehicle with theft-proofed vehicle wheels comprises a plurality of wheel hubs 8; 8'and at least one vehicle wheel 13; 13'. According to this preferred embodiment, the vehicle wheel 13; 13' is mounted, or the vehicle wheels are mounted, to the wheel hub 8; 8'by means of at least one screw device 1; 1'according to the invention being part of an assembly according to the invention.

In a particularly advantageous embodiment of the motor vehicle according to the invention, the motor vehicle is a private car in which the central portions of the vehicle wheels 13; 13'comprise exclusive rims with a special design. In this embodiment, the theft- proofing provided by the present invention is of course of a particularly high value, since the type of rims in question are very expensive and are unusually theft-desirable.

The present invention should by no means be regarded as being limited to what has been described in the foregoing in connection with the preferred embodiments, or to what is

shown in the attached drawings, but the scope of the invention is defined by the accompanying claims.

Accordingly, within the scope of the invention, it is conceivable with embodiments of the motor vehicle according to the invention in which only one, several or all vehicle wheels are theft-proofed by means of one or several assemblies according to the invention.

Furthermore, it is conceivable with embodiments of the assembly according to the invention in which one, several or all included screw devices are in accordance with the invention.

When the geometric design of the sleeve in the screw device according to the invention is concerned, many different embodiments are conceivable.

Accordingly, it is for example conceivable that recesses or cavities have been made in the sleeve with the intention to save weight and material. In such embodiments it must be taken into consideration that the recesses or cavities must not make it easier for unauthorised persons to achieve locking between the sleeve and the screw or to remove the sleeve by means of breaking it.

In the case of a sleeve with the basic shape which is shown in for example Fig. 1, it is conceivable with a suitable number of recesses or grooves which extend radially inwards from the circumference 15 of the sleeve 3. It is also conceivable with embodiments with axially extending through-holes or radial recesses in the periphery of the sleeve. It is also conceivable that a suitable number of recesses are made in the surface of the sleeve 3 which faces upwards in Fig. 1, between the circumference and the central portion.

Similar recesses, cavities or holes can be made in sleeves 3', 3". 3"', 3""with the basic shapes shown in Figs. 5-8. Accordingly, the mantle surface of the sleeve 3", 3"'also can be bevelled, or the sleeve 3""can be designed with a smaller circumference 24""at the bottom that at the top 15"".

It is also conceivable with many different material types for use as the first material in the sleeve, and as the second material in the first end of the lock member, for example embodiments in which the sleeve is of a reinforced polymer material and the lock member of a metal alloy with a higher hardness than the polymer material.

The present invention can advantageously be practised so that a single screw device according to the invention is included in the assembly according to the invention, while the remaining wheel screws are of a conventional type.

In case a combination of conventional wheel screws and screw devices according to the invention are intended to be used for mounting the same vehicle wheel, the geometric design of the sleeve, and the choice of material for sleeve and lock member can also be utilised for regulating the total weight of the screw device according to the invention so that it corresponds as well as possible to the weight of the conventional wheel screws. This makes it possible to avoid bias problems with the mounted vehicle wheel.

Furthermore, it should be noted that the expression"screw"used herein is intended to include all types of members which can be screwed in, independently of the cross-section, length or geometrical design of the threaded portion.

Furthermore, the key being part of the assembly according to the invention can advantageously be attached to or fit together with a suitably designed handle, or function as an intermediate adapter for coupling to a pneumatic screw driver.

In order to render undue thefts even more difficult, assemblies according to the invention are advantageously designed with individual keys/lock grooves.

Fig. 9 shows an assembly according to a particularly preferred embodiment of the invention, including a screw device comprising a screw 2""', a sleeve 3""'and a lock member 4""'. Furthermore, the assembly comprises a key 19', which is indicated with dash- dotted lines in Fig. 9. In the particularly preferred embodiment, a male coupling portion of a key member 23'has been pressed into a female coupling portion in the key 19'.

Furthermore, the key 19'is provided with an annular recessed portion 25, which in Fig. 9 faces downwards towards the sleeve 3""'and receives a an annular protruding portion 26 of the sleeve 3""'. As is evident from Fig. 9, the recessed and protruding portions both have cooperating conical or V-shaped cross sections. When an end user wants to couple the key 19'to the lock member 4""', these corresponding conical or V-shaped surfaces will guide the key member 23'into its correct position in the lock groove 9"'when the end user presses the key 19'against the protruding portion 26 of the sleeve 3""'and simultaneously rotates the key 19'around its longitudinal axis. This is made possible by distance 1 being smaller than distance L in Fig. 9. The protruding portion 26 of the guiding surface of the sleeve 3""'may protrude from the upper surface of the lock member 4""', as shown in Fig.

9, but may also be flush with or slightly below the level of said upper surface.

Accordingly, this geometrical design replaces the above-mentioned guiding pin.

Furthermore, this embodiment is advantageous from an economic point of view since only the key member 23'and the lock member 4""'have to be replaced in order to provide individual assemblies.