Abstract:
A method of making a wheel from a rim selected from a plurality of rims of different nominal diameters, a plurality of flanges of different configurations, and a disc, the method including selecting from the plurality of rims a rim of a desired diameter, selecting from the plurality of flanges a flange of an appropriate configuration so that when the flange is secured to the rim, the flange provides a mounting for the disc, and mounting the disc in the rim by attaching the disc to the flange.

Description:
BACKGROUND TO THE INVENTION 
     This invention relates to a method of making a wheel and more particularly but not exclusively a ground engaging wheel for a vehicle such as a tractor or an excavating/loading or like vehicle or machine. However the invention may be applied to a method of making a wheel for another purpose, although preferably for a ground engaging wheel of a vehicle or machine. 
     DESCRIPTION OF THE PRIOR ART 
     Tractor wheels for example, are made in different sizes to suit the vehicles on which the wheels are used. Tractor wheels made by different manufacturing methods are known. 
     First, a tractor wheel may be made by fixing a, usually round, disc in a rim, for example by welding. The configuration of the wheel is thus fixed and to produce a range of wheels of different diameters it is necessary to make a range of rims of varying diameter, and to make a range of discs of matching size. It is common for the disc of such a wheel to be fixed in the rim by means of a flange means which is secured to the rim and provides a mounting for the disc. 
     Thus for example, to produce a range of three wheel diameters, three alternative rims and three alternative discs need to be produced although a common configuration flange means for the wheels may be used. 
     Second, a tractor wheel may be made by securing in the rim e.g. by welding, a plurality of lugs to which the disc is attached at discrete mounting positions. The disc is usually nominally square with the corners removed to provide mounting positions. 
     Such a construction has the advantage over a fixed disc wheel that the disc may be mounted on either side of the lugs, with or without spacers, and the disc may be reversed, so as to provide a variety of wheel configurations so that the tracking between a pair of such wheels on a common axle, may be changed. This is a desirable feature for farmers for example who may require the tracking to be set to match the distance between furrows for example, in a field. Hence the disc is usually attached to the lugs by fastenings such as bolts which are releasable to enable track adjustments to be made. 
     With such a construction, to produce a range of wheels of different diameters it is necessary to make a range of rims of varying diameter as in the first construction described, and again to make a range of discs of matching size. 
     Thus again, to produce a range of three wheel diameters, three alternative rims and three alternative discs need to be produced although a common configuration lugs for the wheels may be used. 
     Third, to provide a wheel construction having sufficient torque strength for use on a modern higher power tractor, whilst being adjustable to accommodate different desired track widths, a construction similar to the lug construction described may be used but in which there is a flange means secured in the rim, e.g. by welding, rather than lugs. A disc is thus fixed in the rim by attaching the disc to the flange means, usually at discrete mounting positions provided by the flange means, again by means of releasable fastenings. 
     Again to produce a range of say, three wheel diameter sizes, three alternative diameter rims, and three alternative size discs are required, although a common flange configuration for the three wheel sizes may be used. 
     In each case described, it is necessary to produce a range of discs in order to provide different sized wheels which is expensive in terms of tooling and production. 
     SUMMARY OF THE INVENTION 
     According to the first aspect of the invention we provide a method of making a wheel from a rim selected from a plurality of rims of different nominal diameters, a plurality of flange means of different configurations, and a disc, the method comprising selecting from the plurality of rims a rim of a desired diameter, selecting from the plurality of flange means a flange means of an appropriate configuration so that when the flange means is secured to the rim, the flange means provides a mounting for the disc, and mounting the disc in the rim by attaching the disc to the flange means. 
     Thus in contrast with all of the prior art methods described, a range of wheels of alternative diameters may be produced in which each of the different diameter wheels utilises the same configuration disc thus resulting in a substantial saving in production costs. Of course, different flange means need to be made for the different diameter wheels but such flanges are much less expensive components to produce. 
     In one embodiment the disc may be circular around its periphery and may be attached to the flange means around substantially the entire circumference of the disc, for example by welding. 
     Preferably though the disc is of a non-circular configuration around its periphery, and the method comprises attaching the disc to the flange means at a plurality of mounting stations provided by the flange means. 
     Thus the disc may be nominally square around its periphery, with the corners of the square removed to provide positions at which the disc is attached to the flange means at the mounting stations. 
     Where it is desired to provide a wheel which is adjustable, the disc is preferably attached to the flange means by reusable releasable fastening means such as threaded fasteners which may provide formations whereby the fasteners may readily be released and re-used, so as to provide an adjustable wheel. The attachment of the disc to flange means may utilise spacers as desired so that the wheel tracking of a pair of wheels on a common axle may be adjusted to a desired tracking. 
     However it is envisaged that the disc may be attached to the flange means by permanent fasteners by which we mean fasteners which cannot be readily released and re-used, such as rivets, for one example, or even threaded fasteners which when tightened to a desired torque, become permanently damaged and are not re-usable. For example a formation necessary to tighten and release such a fastener may break off so that the faster cannot then readily be released. 
     In this way, the wheel is not adjustable by for example a vehicle operator, although the disc and flange means may be separated e.g. by drilling out the fastener so that the wheel may be repaired for example, by replacing a component part thereof, i.e. the rim or the disc. 
     The flange means may each comprises a first generally circular part which is adapted to be secured to the rim and a second generally circular flange part which is adapted to extend radially inwardly of the rim and provide the mounting for the disc, the method comprising attaching the disc to the second flange part. 
     The flange means may be of alternative configurations by virtue of at least some of the second flange parts of the plurality of flange means being longer in a direction in use radially inwardly of the rim, than others of the second flange parts, so that the method may comprise selecting a flange means from the plurality of flange means, in which the second flange part is of a sufficient length so that in use the second flange part extends radially inwardly sufficiently far for the disc to be attached to the second flange part of the selected flange means. 
     A typical range of wheels comprises three wheels of different diameter. Thus the method may comprise providing at least three alternative configurations of flange means, the first configuration having a second flange part of a length greater than the length of the second flange part of the second configuration of flange means, and the second flange part of the second configuration flange means being of a length greater than the second flange part of the third configuration of flange means. 
     According to a second aspect of the invention we provide a method of making a wheel from a rim and a disc, utilising mounting means secured to the rim to provide a mounting for the disc in the rim, wherein the method comprises attaching the disc to the mounting means by permanent fasteners which cannot be readily released and re-used. 
     According to a third aspect of the invention we provide a set of wheels each comprising a rim, a disc and a flange means providing a mounting for the disc in the rim, each of the wheels of the set having a rim with a different nominal diameter, a disc of common configuration to all the wheels of the set, and a flange means of a different configuration to the flange means of the other wheel or wheels of the set. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an illustrative side view of a tractor wheel which may be made by the method of the invention; 
     FIG. 2 shows how a range of three such wheels of different diameters may be made by a prior art method; 
     FIG. 3 shows how a range of three such wheels of different diameters are made by the method of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1 of the drawings, there is shown a wheel  10 , being a tractor wheel comprising a rim  11  on which a tyre  12  is mounted. 
     Within the rim  11 , there is provided a disc  15  by means of which the wheel  10  may be secured relative to an axle on a tractor. 
     The disc  15  is of a nominally square configuration with the corners removed and the disc  15  is fixed in the rim  11  by a plurality of fastenings  18  which engage a flange means  20  at four mounting stations. The flange means  20  extends circumferentially around the rim  11  and is secured in the rim by means of welding. 
     Similar wheels are known in which the periphery of the disc  15  is generally circular and is secured to a flange means  20 , by welding around substantially the entire periphery. 
     In order to produce a range of such wheels  10 , of different diameters, conventionally it is essential to provide different configurations of discs  15  as well as different configuration rims  11 , as shown in FIG.  2 . 
     In FIG. 2, cross sections through three wheels  10   a ,  10   b  and  10   c  are indicated (only half the wheel being shown), the rims  11   a,    11   b  and  11   c  being of different diameters. Rim  11   b  is of larger diameter than rim  11   a,  but of smaller diameter than  11   c.    
     In each case, a wheel is produced to the required diameter by taking a rim  11   a,    11   b,    11   c  of the appropriate diameter, and securing in the rim a flange means  20 . The flange means  20  comprises a first part  21  and second flange part  22 , integrally provided preferably, by pressing for example. 
     The first part  21  is secured by welding in the rim  11   a,    11   b  or  11   c  and the second part  22  is transverse to the first flange part  21  and extends radially inwardly of the rim  11   a,    11   b,    11   c  and provides a mounting for a disc  15   a ,  15   b ,  15   c.    
     Because the flange means  20  are common to the three wheels  10   a ,  10   b,    10   c  of the range, necessarily, three different size and configuration discs  15   a ,  15   b  and  15   c  are required in order to produce a range of three wheels. 
     The discs  15   a ,  15   b  and  15   c  are large and expensive to produce and accordingly production of three discs of alternative configuration, is expensive. 
     The discs  15   a ,  15   b ,  15   c  may be attached to the second part  22  of the flange means  20  in each respective wheel construction, either permanently e.g. by welding, or preferably by means of fasteners  18 , utilising spacers as necessary so that the wheel produced is an adjustable wheel, the disc  15   a ,  15   b ,  15   c  being attachable to either side of the flange means  20  and spacers being used as required, so that the tracking distance between a pair of such wheels on a common axle may be adjusted. 
     In accordance with the invention, a range of three wheels  10   a ,  10   b,    10   c  is produced without a requirement for producing three discs  15   a ,  15   b ,  15   c  of alternative configurations. 
     Referring particularly to FIG. 3, it can be seen that in each of the three wheel constructions  10   a,    10   b,    10   c,  a common disc  15  may be used. Thus tooling is only required to produce a disc  15  of a single configuration. 
     To achieve this, it is necessary to provide alternative flange means  20   a ,  20   b  and  20   c  for each of the three wheels sizes. 
     Each of the flange means  20   a ,  20   b ,  20   c  comprises a first part  21   a ,  21   b ,  21   c  which is secured to the respective rim  11   a,    11   b,    11   c  by welding for example, and a second flange part  22   a ,  22   b ,  22   c  which again is integrally provided with the first flange part  21   a ,  21   b ,  21   c , but extends in use radially inwardly of the wheel  10   a,    10   b,    10   c.  The second part  22   a  of flange means  20   a  is shorter in length (radially inwardly of the wheel) than the second part  22   b  of the second flange means  20   b . This in turn is of shorter length than the second flange part  22   c  of the flange means  20   c  of the wheel construction  10   c,  in which the rim  11   c  is of the greatest diameter. 
     Thus the flange means  20   a ,  20   b  and  20   c  are each of a different configuration so as to provide an appropriate mounting for a common disc  15  within the different diameter rims  11   a,    11   b  and  11   c.    
     The flange means  20   a  of the smallest diameter wheel construction  10   a  is of a simple L shape, with one limb of the L providing the flange part  21  a which is secured to the rim  11   a,  and the second limb of the L providing the second flange part  22   a.    
     The second flange part  22   b  of the second flange means  20   b  is of a more convoluted configuration so as to provide the necessary strength for the longer second flange part  22   b  of the flange means  20   b , and the second flange part  22   c  of the flange means  20   c  of the largest diameter wheel construction  10   c  is of even more convoluted configuration, so as to provide even greater strength to support the rim  11   c  relative to the disc  15 . 
     In a method of making a wheel in accordance with the invention, the common disc  15  may be attached to the respective flange means  20   a ,  20   b ,  20   c  in any desired manner. Where the disc  15  is circular around its periphery, it may be welded to the respective flange means  20   a ,  20   b ,  20   c . Alternatively, the disc  15  may be attached to its respective flange means  20   a ,  20   b ,  20   c  by reusable threaded fasteners such as nuts and bolts, and spacers may be utilised so that the wheel  10   a ,  10   b,    10   c  is adjustable, for different track widths between a pair of such wheels on a common axis. In another arrangement, the disc  15  may be attached to its respective flange means  20   a ,  20   b ,  20   c  by fastenings which are not reusable. Examples of such fastenings are rivets, or fasteners which are threaded and which may be tightened to a predetermined torque before the fasteners become permanently damaged so that they cannot subsequently be readily released. 
     Thus where it is required to provide a wheel in which the track of the wheel is fixed rather than adjustable, non-reusable fasteners may be utilised. 
     Of course, with non-reusable fasteners, it would always be possible to separate the disc  15  and rim  11   a,  or  11   b,  or  11   c  by drilling out such fasteners for example, to facilitate repair of the wheel, but an operator of a tractor for example, would not be able readily to adjust the wheel track. 
     Various modifications may be made with departing from the scope of the invention. 
     In the example described with reference to FIG. 3 the drawings, a range of three wheel sizes may be produced from the components described. In another arrangement, only two wheels of alternative size, but utilising a common disc configuration may be made, or more than three wheels of different diameters may be produced. 
     Although as described, the flange means  20   a ,  20   b  and  20   c  have been secured in the rim  11   a,    11   b,    11   c  by welding, any other suitable technique for securing the flange means  20   a ,  20   b ,  20   c  in position in the rim may alternatively be used. 
     The flange means  20   a  and  20   b  and  20   c  obviously need to be of different configurations so as to enable a common disc  15  to be used with different diameter rims  11   a,    11   b,    11   c,  but one or more of the flange means  20   a ,  20   b ,  20   c  may be of alternative configurations to those shown in FIG.  3 . 
     Although the invention has been described with reference to a tractor wheel, the invention may be applied to produce a range of wheels for other uses, from common components, for example, wheels for excavators, loaders or other working machines, or for vehicles in general. Preferably though the invention is utilised to produce a range of ground engaging wheels. 
     As shown in FIGS. 2 and 3, the disc  15  is of a simple plain construction, but it will be appreciated by those skilled in the art, that a disc  15  more usually is of a complex shape which is what makes its production in three alternative sizes, so expensive.