WO1991008163A1

WO1991008163A1 - An auxiliary for the mounting of car wheels on wheel hubs, particularly of balancing machines

Info

Publication number: WO1991008163A1
Application number: PCT/DK1990/000316
Authority: WO
Inventors: Arne Hjorth Hansen
Original assignee: Arne Hjorth Hansen
Priority date: 1989-12-04
Filing date: 1990-12-04
Publication date: 1991-06-13
Also published as: AU7895591A

Abstract

Motorcar wheels being mounted in a vertical position on rotation hubs (6) of wheel balancing machines are guided into an accurately centered position by means of cooperating conical portions on the hub and on the wheel, but nevertheless it can be observed that the centering is not entirely correct, because the wheel 'pulls downwardly' due to the gravity. According to the invention this effect is counteracted by placing the wheel on a support member (22) of an auxiliary apparatus (18) adapted to provide an air spring underneath the support member to the effect that the air spring equalizes the gravity of the wheel, such that the wheel be freely movable in a 'weightless' condition a certain distance up and down. Thus, the wheel can easily be height adjusted to assume its mounting level, and by its final tightening to the hub the wheel will still be 'weightless', whereby it will be very accurately centered. Moreover, the auxiliary apparatus can be arranged so as to be horizontally displaceable, such that it can be used also for bringing the wheel (8) onto the carrier hub (6). Preferably use is made of a permanent air spring and of power driven means (62, 64) for temporarily pressing down the support member (22) to a lower receiving and delivering position of the wheels.

Description

An auxiliary for the mounting of car wheels on wheel hubs, particularly of balancing machines.

The present invention relates to an auxiliary device for use when mounting car wheels on rotary hubs. It is an almost universal standard that the wheel rims are provided with bolting holes of a conical shape for cooperation with hub portions or mounting bolts of a corresponding conical shape, whereby a centered tighten¬ ing of the wheel on the hub carrier can be ensured, which is of course of utmost importance.

It is a quite common practice to rely fully on the centering effect obtained by the tightening of the coni¬ cal bolt heads, the wheel initially being placed just approximately centered next to the wheel holder, where¬ after the bolts are tightened, usually with the wheel hanging on the bolts. It has been found, however, that the expected accurate centering is not really achieved, since e.g. a hanging wheel will be secured with a small, yet noticeable decentering in the downward direction, such that it is quite necessary to thereafter carry out a balancing of the wheel.

Similar circumstances occur when according to modern practice a wheel is mounted on a hub portion of a special or separate balancing apparatus, by means of which the balancing is accomplished externally, where¬ after the wheel is mounted on a hub of the car, with or without a subsequent fine balancing. In principle the same problem will then occur again, but now it is less pronounced, because the wheel itself has now already been 'correctly' balanced, though with the said inherent gravity conditioned centering error.

While this has so far been accepted as a kind of basic condition in connection with wheel mounting, then by the invention it has been recognized that a more accurate centering and therewith in many cases an avoidance of a subsequent balancing can be achieved if care is taken that the wheel already by the initial mounting is brought into a position, in which it is centered with high accuracy relatively to the wheel holder. Then the final tightening of the bolts may be effected without the wheel at the same time being in¬ fluenced by noticeable displacement forces, whereby it will be possible to obtain an improved centering by the tightening of the wheel bolts. This could be realized by the use of a height adjustable support for the wheel, but presumably such an arrangement would be difficult to work with.

By the invention a more advantageous solution has been provided, in that the invention is based on the consideration that the initial centering of the wheel is not particularly critical, if the wheel is supported in a manner such that it appears as weightless, and on that basis the invention is characterized in that the wheel is mounted on a vertically movable support, which is influenced upwardly by a force corresponding substan¬ tially to the weight of the wheel. When the wheel weight is thus balanced out it will be possible to freely displace the wheel up- and downwardly, and when the support is additionally displaceable towards the hub, on which the wheel is to be mounted, then the operator may rapidly and easily cause the wheel to be guided inwardly against the hub and effect the height adjustments neces¬ sary to make the wheel assume a correct or very nearly correct height position. For the final mounting it will then not be particularly important whether the wheel is somewhat displaced by the final bolting and the associ¬ ated centering, since an associated displacement of the wheel will take place without any resistance, not either in the horizontal direction, in which the wheel may just roll on the support. It should be mentioned that the wheel mounting on the particular balancing machines will normally be ef¬ fected by means of a central nut, without the use of the said conical spanner bolts, but with the use of a cen¬ tral cone cooperating with the central hole of the wheel rim such that the same centering accuracy can be ascer¬ tained. Hereby the wheel is not bound to assume any specific angular position relative the hub, and for that reason the wheel may well roll freely on the support in connection with the horizontal final centering of the wheel.

Systems for making objects 'weightless' with the use of springs, air springs or counterweights are al¬ ready known, but mostly they are used for specific ob¬ jects having a specific weight, while with the invention the weight of the objects is liable to be variable. On that background it is preferred to make use of an air spring with a large volume and with a controllable sup¬ ply of compressed air thereto, such that the spring pressure can be adapted to an actual object weight. Due to the large air volume of the air spring the heavy object may then very easily, e.g. 'by a push with a little finger', be brought to change its height posi¬ tion, such that the wheel in a simple manner can be brought into an 'almost correct' mounting position, in which it will be practically weightless, also by the subsequent forced centering by the mounting.

For the invention it is particularly advantageous that by the building up of the required spring pressure it is possible to obtain at the same time that a wheel supplied at floor level can be lifted to the mounting height of the wheel, e.g. on a balancing spindle, where¬ by the manual handling of the wheel is facilitated con¬ siderably. Likewise, after the balancing operation the wheel can be brought down to the floor level only by relieving the applied air pressure. It will happen frequently, however, that work is carried out on a series of wheels of approximately uni¬ form weight, e.g. because the wheel weight of passenger cars does not vary much, just as the four wheels of a single car will normally have exactly identical weights. According to the invention it will hereby be particular¬ ly suitable if the need for building up and subsequently relieving the required air pressure for each single wheel handling, and this is achievable by the use of means for a power driven depressing of the wheel carrier element in such a manner that this element can be pressed down into a low receiving and delivering level with an associated increase of the air spring force of an air spring having a pre-adapted spring pressure. From this lowered position the wheel carrier element may then be raised to the relevant mounting height just by re¬ leasing the depressing means, whereby the 'almost cor¬ rect' mounting height will reached automatically, with¬ out any separate adjustment of the air pressure in the air spring system.

The entire support apparatus may be placed on a horizontal carrier frame, on which it is displaceable towards the mounting hub. Hereby the wheels, once placed on the carrier plate, can be handled with a minimum of applied force for being moved vertically and horizontal¬ ly as required.

Alternatively a support platform for the wheels may be mounted horizontally displaceably at the upper end of an underlying, stationary support structure, this being preferred with equipment for handling large and heavy wheels.

In the following the invention is described in more detail with reference to the drawing, in which:-

Fig. 1 is a perspective view of a balancing appara¬ tus provided with a carrier device according to the invention. Fig. 2 is a lateral view of a modified carrier device, and

Fig. 3 is a perspective view of a further modified carrier device.

In Fig. 1 is indicated a balancing apparatus 2 having in the usual manner a horizontally projecting balancing shaft 4 with an outer mounting head 6 for a wheel 7 to be balanced. The head 6 has contact flange 8 and a cone 10 protruding therefrom, the cone continuing in an outer, threaded pin 12. In its rim the wheel 8 has a central hole 14 that can be inserted over the pin 12, whereafter the wheel is mountable on the headβ by means of an outer, non-illustrated nut and an associated washer disc or cup. The cone 10 is designed so as to match the hole 14 for centering the wheel when it is mounted. In the rim there are further holes 16 to be used for receiving tightening bolts by the later, cen¬ tered mounting of the wheel on a wheel hub of a vehicle.

It has been common practice to lift the wheel 8 manually up onto the shaft pin 12 and then mount it while it hangs freely on the pin, with the drawback already discussed. It adds to this drawback that it is very labour and time consuming to effect the manual lifting and positioning of the wheel.

Once the wheel has been brought into position and is fixed the shaft 4 is rotated, and the apparatus will then indicate which unbalance there is, whereafter the unbalance can be equalized by means of weight members that are mounted on the edge of the wheel rim.

According to the present invention the apparatus is supplemented with a support device for the wheel 8, the device comprising a telescopic post 18, the upper part 20 of which having a top carrier plate 22 for the wheel. The post 18 is placed on a horizontal guiding frame 24 comprising a guiding shaft 26, which is surrounded by a bushing 28 on the post 18, and a rail 30 forming a rol- ling way for a support roller 32 on the post. To the lower end of the post is connected a compressed air conduit 34, which passes through a pedal valve 36.

Inside the post, as shown in dotted lines, there is mounted a vertical air cylinder 38 having its lower end connected to the conduit 34, this further being con¬ nected to a relatively large container 40 inside the post 18.

When a wheel is to be balanced it is placed upright on the plate 22, and by operating a pedal 42 on the pedal valve 36 compressed air is let into the system 34,38,40 until til pressure has been built up suffi¬ ciently -for the cylinder 38 to force the plate 22 up¬ wardly. This will not happen in any particularly well defined manner, as the air in the relatively large con¬ tainer or tank 40 will act as an air spring. On the other hand, however, this will imply that the operator, after having released the valve 42, can easily push the plate 22 up and down, as a displacement of e.g. 10-15 cm of the piston in the relatively narrow cylinder 38 will result in but a very small pressure change in the system. Unavoidably a certain movement friction will occur in the cylinder, and even though this friction should preferably be low, it will nevertheless exhibit the effect of stabilizing the raised system in each new position, to which it is brought, such that the vertical movements are not entirely uncontrolled.

Hereby the operator can very easily bring the wheel to an approximately correct level and then displace the whole carrier device towards the mounting head 6. During this displacement the operator can effect required small corrections of the height position of the wheel, such that the central hole 14 can easily be placed correctly for its introduction over the shaft pin 12.

After being mounted and balanced the wheel will be correspondingly easy to release from its engagement with the mounting head, and the operator may then actuate a relief pedal 44 on the valve 36, whereby the wheel will be calmly lowered into its lower position, from which it can be taken down or rolled out.

An alternative solution will be to begin with an automatic weighing of the wheel loaded system, whereby the valve 36 can be controlled so as to provide just the required air pressure. A similar automatic control can be achieved with the use of a sensor sensing the initial raising of the system, when the pressure is sufficiently high, and thereby causes the supply of compressed air to be stopped at a suitable pressure, which may well be slightly higher than the pressure, at which the initial raising occurs.

There may be other fields of application, where a support system according to the invention can be used with advantage, so the invention is not necessarily limited to the use here discussed. Another relevant example of use will be the mounting of the finished wheels on the wheel hubs of a motor car or truck, where the invention may be used for a continued mounting of the wheels in an easily movable, 'weightless' condition. Here there is no room for a supporting device underneath the wheel, but the device may be designed such that from the top plate 22 there is a connection down to the ground level, where a plate can then be held for receiv¬ ing the wheel and lifting it slightly off the ground or floor. The device may be supported on wheels for easy insertion of the wheel onto the hub, and of course the device will also be usable by the dismounting of wheels or lowering of other heavy objects in an easy, con¬ trolled manner.

The preferred device shown in Fig. 2 comprises a pressure tank 46, in which there is provided a depending piston cylinder 48 that is open in the bottom and holds an upwardly displaceable piston rod 50 having a lower piston 52 and an upper carrier platform 54 for a wheel. Through a side stub 56 compressed air can be fed to the tank to such an extent that the lower side of the piston will be permanently exposed to a force which is suitable for raising the platform to a relevant mounting height, when loaded by a car wheel. However, the air supply conduit passes through a +/- valve 58, such that should the need arise it is possible to adjust the pressure upwards or downwards for adaptation to special wheels.

At the top the piston rod passes through a sealing bushing 60, which is provided with a radial connection to an inlet 62 for compressed air supplied from an air source through an on/off valve 64, e.g. a pedal operated valve. The inlet 62 is in open connection with the inte¬ rior of the piston cylinder, such that a pressure ap¬ plied through this inlet will act on the top side of the piston 52, thus seeking to force the piston downwardly. The conditions are adapted such that by an opening of the valve 64 the piston will be forced down to its bot¬ tom position against the action of the air pressure from the surrounding tank, whereby it is possible to move the platform down to a lower position for easy reception of a wheel. When thereafter the valve 64 is switched to a closing/venting position the air pressure in the tank will be activated for raising the piston rod 50 and therewith the wheel to the desired mounting height.

It is thus achieved that the air pressure in the tank may remain constant, though with the said possibi¬ lity of being adjusted by the handling of nontypical tyres, and that the volume of air which is to be let in and out by each operation will be much smaller than with the embodiments in which it is the air pressure in the tank itself which should be built up and relieved, re¬ spectively.

The invention is not limited with respect to the temporary pressing down of the platform having to be done by means of compressed air, as in principle other means may well be used, e.g. a mechanical rod system or a driving pinion cooperating with a tooth rack on the piston rod; such a pinion can be switched to free rota¬ tion when the platform is ready to be lifted.

For the embodiment shown in Fig. 3, which is adapted for handling heavy wheels, it is endavoured that the carrier platform 22 in its lowermost position shall be located in a low height above the floor, such that the wheel can be rolled directly onto the platform and thereafter be lifted to the required height, i.e. with¬ out any manual lifting of the wheel. As illustrated this is achieved by a carrier rail system 70 for the platform 22 being moveably connected with with a floor supported chassis 72 through a pair of parallelogram rods 74, which are pivotal between a lying position and a swung up position, in both positions with the carrier platform 22 disposed horizontally. The pivoting up and down is controlled by means of a cylinder 76, which corresponds entirely to the cylinder 46 of Fig. 2 and is mounted in a lying position between the chassis 72 and and the carrier rail system 70 in such a manner that it can effect the desired pivoting up and down of this system 70 and support the same in the raised position thereof with the said air spring action.

In this embodiment the carrying chassis 72 is sup¬ ported non-displaceably on the floor surface, while the upper platform 22 is displaceably arranged on the car¬ rier rail system 70, such that the desired lateral dis- placeability of the supported wheel is secured anyway. It is deemed unnecessary at this place to explain in more detail why, by the handling of heavy wheels, it is preferable to arrange for the displaceability of the platform 22 at the top rather than at the bottom of the device.

Claims

C L A I M S

1. An auxiliary apparatus for use by the mounting of car wheels on a rotation hub, primarily in a balanc¬ ing machine, characterized in that it comprises a car¬ rier element (22,54) for the wheel and a support for this carrier element, said support being designed such that the carrier element is easily displaceable up- and downwardly against the action of an upwardly directed force, preferably from an air spring, which substantial¬ ly equalizes the weight of the carrier element and the wheel.

2. An apparatus according to claim 1, characterized in that additionally it comprises guiding means for an easy horizontal displaceability of the carrier element towards and away from the rotation hub.

3. An apparatus according to claim 1, characterized in that the support comprises a vertical cylinder/piston system associated with means for building up the re¬ quired pressure for establishing the said upwardly di¬ rected force, and that the air volume of the system is so large that the pressure therein will not change es¬ sentially when the carrier element is moved up and down along a predetermined stretch, e.g. of 10-20 cm.

4. An apparatus according to claim 3, characterized in that the cylinder/piston system is constituted by a narrow air cylinder, the active pressure chamber of which is connected with a pressure tank, which has a relatively large volume, and with a valve for introduc¬ ing compressed air into the pressure chamber until the said required pressure has been established.

5. An apparatus according to claim 3, characterized in that the support comprises a pressure tank with a relatively large volume and with a dive piston rod pro¬ jecting downwardly therein.

6. An apparatus according to claim 1, characterized in that the air spring is substantially constantly oper¬ ative and that the apparatus comprises power driven means for temporarily pressing the carrier element down into a bottom position apt for receiving and delivering the the wheels, against the action of the air spring.

7. n apparatus according to claim 6, characterized in that the bottom pressing means are constituted by means for introducing compressed air above a pressure piston, the underside of which is affected by the pres¬ sure of the air spring.

8. An apparatus according to claim 1, characterized in that the support of the carrier element is designed such that it can move the carrier element between a lowered position very close to the floor and a mounting position lifted thereabove.