TYRE LINE FOR USE IN WORKSHOPS

Tyre Line for Use in Workshops

The present invention concerns a tyre line for use in workshops, including a number of apparatus units, inter alia a wheel lift, a tyre pressing apparatus, a tyre changing ma- chine, a pump station, a transfer unit and a balancing machine. For effecting diverse work on vehicle wheels already in use, it is necessary to perform a pressing free of the tyre sides at first from the engagement established between the tyre beads and the rims, as this engagement grows more and more permanent over time. In connection with semi-industrial tyre changing machines, it is well-known to use an integrated free pressing equipment, which more or less automatically can perform the necessary pressing free as an integrated operation, but with more common workshop machines this integration is not driven farther than e.g. at the side of the machine there may be found pressing tool, which can be operated for an initial pressing with the wheel standing on the floor. This provides a bad working position at positioning the wheel and inspection of correct placing in relation to the tool, and furthermore the operator is then to lift the wheel up by himself to lying position on the work plane of the tyre changing machine.

By the invention it has been found that these circumstances may be improved consid- erably if instead use is made of apparatus units, which can fulfil the task of lifting the wheel up to lying position on a work table, above which the necessary pressing free tool is provided, from which table the wheel can be laterally pushed, rolled or turned over upon the work plane of the tyre changing machine. From the tyre changing machine the wheel can be laterally pushed over to a pump station where the tyre is in- flated. From the pump station, the wheel is rolled/tipped down on a transfer unit, where the wheel is turned 180° and is passed over the shaft of the balancing machine. With a tyre line according to the invention there is possibility of using an ergonomically far more suitable arrangement, both for lifting, handling and for taking down the renovated wheel.

On this background, by the invention there is aimed at indicating a tyre line which with simple means is able to function in a suitable way and which can be provided with a minimum use of space. The tyre pressing apparatus according to the invention includes a supporting chassis with an upper side provided with rollers and which a overlying pressing tool and a wheel lift or lifting unit disposed at one side of the chassis, the lifting unit/ramp being connected with an actuator such as an air cylinder for lifting the ramp between a lowered position in which at least one wheel can be rolled in on a wheel carrying member at floor level and be lifted to a position in plane with the fixed roller top side, so that the lifted wheel then in a simple way can be tipped down on or rolled in on the "work table". The wheel lifter may be provided in continuation of the fixed roller top side, or it may be disposed transversely of the fixed roller top side.

After being pressed free by means of the overlying pressing tool, the wheel can then be turned directly over upon the tyre changing machine. When the work with this has been finished, the wheel can be moved back to the ramp under use of the fixed roller top side as a passive rollerway, after which the ramp can be actuator controlled for lowering to the starting position, from which the finished wheel may readily be rolled out on the floor.

However, here it is to be noted that the wheel normally will be delivered from the tyre changing machine to a pump station or a balancing machine at the opposite side, so that no use is made of the said returning of the wheels. The lifting unit is then only to be lowered for getting the next wheel.

With this controlled lowering of the lifting unit, the free end is to be controlled down to floor level for achieving that the wheels may easily be rolled to and from, this implies the problem that by such lowering a risk of pinching a foot may occur, be it the foot of the operator or an interested spectator, and it has not been desirable to prescribe a hollow below the end of the lowered lift unit for removing this risk of pinching. By the lifting unit according to the invention it has been realised, however, that the pinching potential will mainly come from the actuator control, as the gravity contribution will be very limited, since the lifting unit is viewed in almost completely down pivoted condition. On this background, by the invention there is indicated the simple solution that the freely hinged ramp only rests against a corresponding co- hinged gallows or frame part, which is projecting appreciably shorter than the lifting arm itself of the ramp, and which constitutes the element interacting with the actuator. This element may thus, under normal conditions, be positively controlling the lifting and lowering of the ramp, and with occurrence of pinching risk, the element may be forcibly controlled to its fully lowered position without presenting any risk by itself, while the ramp then may be stopped in its pinching position without pinching with any contribution from the actuator. Hereby, it is found completely secure to use the construction in question, which is both cheap and very suited.

As mentioned, the tyre line includes further units. These units are known individually, but are not coupled together for a line in which all functions may easily be executed ergonomically correctly.

In order to facilitate the workflow at this line, there are disposed suitable means be- tween or before the different operations for easy transfer of the wheel to the next operation. In particular, the transfer unit between balancing machine and the previous operation, such as a pump station, may be emphasised. This transfer is special, as the wheel is here to be raised and simultaneously to be turned 180° about its vertical axis and finally be moved a distance in over the shaft of the balancing machine, after which it is to be fastened for balancing.

The transfer occurs e.g. from a pump station from which the wheel is received lying on a roller table with a horizontal section and an end pointing downwards with an angle between 0° and 90°, where the roller table has means for braking a wheel that is rolling hereon. The roller table is special in that the last roller before a downward sloping end is equipped with brake means acting as a drag brake and with at least one freely running roller at the downwardly sloping end. When the wheel is brought to stop, it lies in a position where a part of the wheel protrudes over the downwardly sloping end. From this position, the wheel may easily be tipped/raised by the wheel on the projecting part being pressed downwardly and thereby being brought into contact with a roller located at the end of the downward sloping end. From there the wheel rolls, still under the action of the drag brake, down on the platform of the transfer unit in a controlled way. The transfer itself occurs by the wheel, as mentioned, is tipped down on a platform which is equipped with a flat or plate-shaped turntable.

When the wheel has been placed on the turntable of the transfer unit, it may be rotated about its vertical axis and then moved horizontally in over the shaft of the balancing machine without any strenuous lifting. This operation is possible to execute with several different sizes of wheels as the transfer unit according to the invention is provided with a platform which can be displaced to both sides of the centre line of the unit. This pulling provides the possibility of placing the platform in a position allowing that the wheel is turned 180° about its vertical axis without coming in conflict with the delivering unit/roller table or the shaft on the balancing machine.

When the wheel is put on the platform of the transfer unit, it is in a kind of "weight- less" state based on methods known from WO 95/30617 and WO 99/40406. With this unit, the wheel can be moved the whole way from one operation to the next. After e.g. balancing, the transfer unit is used again for moving the wheel to the next operation, which typically will be feeding to a delivering area, e.g. to a wheel dolly known from

WO 99/38713, or similar. The wheel can also be delivered at floor level or at an arbi- trary level between floor and table level.

In a preferred embodiment, the tyre line is arranged so that several common wheel sizes may be handled without any problems of lack of space, still with minimal use of space and with optimal ergonomic work conditions.

The invention is explained in the following in more detail with reference to the drawing, on which:

Fig. 1 is a front view of a tyre line according to the invention, Fig. 2 is a perspective view of a tyre pressing apparatus according to the invention,

Fig. 3 is the same, shown with a received wheel,

Fig. 4 is the same with the wheel turned up,

Fig. 5 is the same with the wheel pushed onto the work table of the apparatus, Fig. 6 is the same under use of an occurring pressing tool, Fig. 7 is a close-up view of the work table of the pressing tool, Fig. 8 is a view corresponding to Fig. 1 with the wheel during turning, Fig. 9 is a plan view of the pressing apparatus shown during pivoting down of the wheel carrying ramp,

Figs. 10 and 11 are perspective views of a modified embodiment of the work table of the tyre pressing apparatus, Figs. 12 and 13 are perspective views of a modified and space saving embodiment of the lifting unit, Fig. 14 is a perspective view of the freely hinged ramp and the co-hinged gallows or frame part, and Fig. 15 is a perspective view of a transfer unit before the balancing machine. Fig. 16 is a front view of a roller table with braking means and of a transfer unit.

Fig. 1 shows a front view of a tyre line 100 according to the invention. The tyre line

100 here consists of six units, namely: a wheel lift 110, a tyre pressing apparatus 120, a tyre changing machine 130, a pump station 140 with roller table 142, a transfer unit 150 and a balancing machine 160. In this embodiment, the line 100 as seen in Fig. 1 is made so that it takes up the least possible space, and so it fulfils the functional re- quirements demanded. In particular, it is the wheel lift 110 and the transfer unit 150 that provides for the special space saving design. The wheel lift 110 is made so it only takes up about one wheel width in the longitudinal direction of the line. One version of the lift 110 can be made so that it can lift one or more wheels 14 at the same time so that they are ready for being pressed free. The transfer unit 150 is made so that its plat- form can be displaced to both sides of a centre line of the unit for better receiving and delivering the wheel 14 to the next operation. The feature that the platform 152 can be displaced to both sides of the centre line of the unit provides the possibility of handling even large wheels without any form of space problems as it is possible to bring the wheel in a position allowing the wheel to be turned about its vertical axis without coming into conflict with a roller table or shaft on the balancing machine. In Fig. 1 is shown two different wheel sizes, illustrating that several sizes can be easily handled with requiring more space for the tyre line 100 in the longitudinal direction. The tyre pressing apparatus shown in Fig. 2 is made with a box chassis 2, which at the top has a work table face with slightly raised, transverse rollers 4 and at the rear have an upright structure 5 for carrying a pressing tool 6 above a retainer plate 8. At the right side a roller ramp 10 is pivotably connected to the table, the ramp 10 resting on the floor in a slightly outward sloping position in the turned-down condition. Outermost or lowermost, this pivoting ramp has a projecting bracket piece 12, which, as outlined in Fig. 3, is suited for forming centred support for a wheel 14 rolled in from the wheel and leaning against the ramp 10.

By operating a control button 16, a not shown air cylinder is actuated for, by extending its piston rod 18, to turn the ramp up to horizontal, Fig. 4, whereby the ramp lies in plane with the work table, so that the wheel quite easily may be displaced over on the table and be brought in correct working position relative to the tool 6.

In a known way, the tool 6 is constituted by an inclining pressing plate with curved front edge, which more or less fits the periphery of the wheel rim. The tool is disposed on a swing arm 19, which by means of a strong air cylinder and a pedal valve 20 can be depressed against the tyre side immediately outside the rim edge for pressing free the said rim bead. Preferably, the tool is suspended in such a tilting way that by de- pressing it will seek to tilt forward its front edge so that it will tilt into the rim immediately after being pressed down from the free rim horn and there scrape along the rim side, whereby is achieved a very secure pressing free of the bead area itself, cf. Fig. 6. By the invention it has be realised that the movement of the tool 6 in between the rim edge and the tyre edge entirely into the root of the tyre edge is decisive for the tyre edge being loosened from the rim with certainty, instead of only bending the bead wire by a straight pressing with the result that the bead wire only becomes even more tight, and the tool moving out against the tyre side with the risk of damaging the tyre side by too strong pressure.

Hereby, it has also been found that the resisting force necessary for achieving the moving of the tool entirely in between rim and tyre edge is so great that a mechanical securing of the rim during the insertion is essential. By the preferred embodiment, this is, however, achieved in a simple way, namely by using a manually moved stopper 22 on a swing arm 24 projecting from the carrier structure 5 of the swing arm 19.

The system may be so adapted that the retainer plate 8 is lifted a bit by a force exerted by the pressure cylinder for the tool 6, so that the table rollers 4 are saved from the strong work pressure without the retainer plate impeding the mobility of the wheel on the work table.

When the pressing free on the chosen position of the wheel has been executed, it will normally be desirable to repeat the pressing free at other places on the rim periphery, i.e. turning the wheel to a new working position. For facilitating such turning, the work table, cf. Fig. 7, is provided with a pair of slightly diverging rollers 26 and two transverse roller 28, which are suspended on a tilting frame 30, which by means of a pedal 32 can be tilted for slightly upward displacing of these rollers, whereby the wheel is very easy to turn.

When all of the first tyre side is hereby pressed free, the wheel is to be turned for pressing free the second side. The apparatus is also provided with an aid for facilitating this operation, namely a flat or possibly slightly bowl shaped disc member 34 at a corner of the work table. When the operator tilts the wheel up on this disc, it will then be very easy to turn the wheel 180° and to tip it down in reversed position, see Fig. 8.

When pressing free has been completed, the wheel is normally rolled over upon the clamping table of the tyre changing machine, which will be located centrally immedi- ately at the left side of the press and will have the same height.

When the wheel has finished renovation on the tyre changing machine, it will usually be pumped and tipped over for vertical mounting on a balancing machine, from where the wheel can be delivered directly to the floor or to a transport vehicle. If a wheel is not to be balanced, it may easily be displaced, tipped or rolled over onto the pressing apparatus, the work table of which then being a passive rollerway for easy further moving of the lying wheel to the raised roller ramp 10, after which the actuator of which may be operated for swinging down the ramp for delivering the wheel to floor level in an almost upright and thereby easily rolled out position. However, it is this pivoting down which, as mentioned before, with or without wheels can give rise to the said pinching risk.

As shown in Fig. 9, the pivoting ramp may, however, be loosely supported against a carrier element 36 on a swing arm or frame 38, which is operatively joined with the piston rod 18 from the air cylinder now designated 40, which is pivotable about a front axis 42. The element 38 is appreciably shorter than the ramp, and it will thus not by itself provide any relevant pinching risk by a forced pivoting down. Furthermore, it will not induce a forced pivoting down of the ramp when this is only loosely supported on the element 38. Hereby, there will not be any serious pinching between the floor and the floor supported end of the pivoting ramp.

It may be an alternative to let the pivoting down only occur by passive aeration of the cylinder 40, possibly through a suitably throttled aeration valve, so that the pivoting down does not become particularly violent by a wheel loaded pivoting ramp, and not at all by an unloaded pivoting ramp.

It is now to be mentioned that the discussed arranging of the pressing table, cf. par- ticularly Fig. 7, is relatively tedious, and the invention also comprises a preferred alternative to this, namely as illustrated in Fig. 10 and 11. The table 50 shown there carries a wheel-sized base plate 52 for a lying wheel, the disc consisting of an upper rubber disc 54 laminated on a lower steel disc 56. The steel disc 56 rests on some fixed plastic blocks 58 and 60, of which the block 58 in functionally identical with the block 8, cf. Fig. 7, i.e. placed on a separate, strongly supported carrying part 62, whereas the blocks 60 are only supported on and fastened to a carrying tabletop 64. In a further alternative, the steel disc 56 can be suspended on balls 60', providing easy turning of the disc 56 on the tabletop 64. At the middle of this tabletop there is formed an aperture 66 accommodating a not shown central pin projecting down from the plate 52.

The disc 52, which immediately can receive a wheel supplied from the roller ramp 10 pivoted up, will hereby be easily turned by manual turning action on the lying wheel, as its tyre will be in distinct frictional connection with the upper rubber disc 54, whereas the lower smooth steel disc will be in low factional contact with support blocks 58 and 60,60'. A particularly low friction with the steel is noted when using support blocks of polyethylene, but it is true that a lying wheel in resting position is not "totally floatingly" supported, so that with a reasonable degree of positional safety it can be turned to a position in which the pressing tool 6 can interact with any peripheral area of the tyre bead.

To this may be added that the base plate 52 will not only be rotatable, but also displacing in plane within the limitation set by the mobility of the said downward pro- jecting centre pin on the base plate 52 within the edges of the central aperture 66 in the tabletop 64. Hereby, for the operator it will be very easy to rotate and displace any wheel lying within a relevant size range for suitable pressing positions with the rim edge /tyre bead lying right under the pressing tool 6.

A further embodiment of the pressing apparatus 120 is made with the base plate 52 suspended on steel balls 60' so that the plate 52 can be freely rotated when displaced in the plane towards the user, and cannot be freely rotated when displaced in the plane in under the pressing tool 6 and away from the user.

Furthermore, wheels of different sizes will be received on a base plate which is placed in advance close to a receiving position for the wheel, and which subsequently is displaced to a delivering or turning position, if need be on a turntable 34 for the raised wheel.

Figs. 12 and 13 both show the same wheel lift 110 but in lowered and lifted positions, respectively. The wheel carrying part 12 is here made with a hole ensuring that the wheel 14 does not roll during lifting. As mentioned above, there may be space for more wheels 14 at a time. In such a case there will be a device securing all wheels, possibly a hole for each wheel. In Fig. 14 the same wheel lifter 110 is seen again though here with the wheel lifting part fixed in raised position in order to show how the ramp 10 is loosely support against a carrier element 36 on a swing arm 38, which, as described by Fig. 9, is in operational connection with the piston rod 18 from the air cylinder 40, which is pivoting about an axis 42. The system seen in Fig. 14 has the same advantages as described by Fig. 9.

The transfer unit 150 seen in Fig. 15 is disposed between a pump station 140, only the roller table 142 is here seen, and a balancing machine 160. On the roller table 142 is seen the brake means 144 ensuring that the wheel 14 stops at the end of the roller table 142 when the next wheel is pushed into the pump station 140. On the transfer unit 150 is sees the platform 152 which the wheel 14 is tipped down upon. On the platform 152 is mounted a turntable 34 of the same type used at the tyre pressing apparatus 120. The turntable 34 provides that the wheel 14 is easily and unhindered can be rotated about its vertical axis before balancing. As mentioned by Fig. 1, the transfer unit has the feature that even large wheels are allowed to be handled without any space problems, whereas the tyre line still may be made so that it only takes up minimal space in a workshop.

Fig. 16 shows, as does Fig. 15, a roller table 142, a transfer unit 150 and a balancing machine 160. In this Figure is clearly seen how the wheel 14 is tipped from the roller table 142 over the roller 143, which is provided with brake means 144 in the form of a drag brake 144, and down towards the downwardly sloping end 146 for abutment on a roller 148, which is placed at the end of the roller table. From here the wheel 14 rolls, still under the action from the drag brake 144, in a controlled manner down upon the platform 152 of the transfer unit. In a preferred embodiment, the downward sloping end 146 of the roller table has an angle about 40° with a horizontal plane.

When the wheel 14 is in contact with the platform 152 of the transfer unit, it is raised easily and unencumbered and may be rotated about its vertical axis for mounting on the balancing machine 160.