The invention concerns a method of fitting a tyre round a rim provided with spokes and a valve hole, which tyre comprises an innertube that can be filled with air through a valve and an outer cover having edges, wherein first the valve of the innertube is put through the valve hole of the rim, and the edges of the outer cover near the valve hole are positioned between the rim's legs, and wherein subsequently the entire edge of the outer cover is placed between the rim' s legs with the aid of guide means moving along the rim while engaging the entire edge of the outer cover.

Such a method is known, for instance, from US 2439615, describing an apparatus wherein the guide means are mounted on two arms moving in opposite directions. Moving the arms in opposite directions aims to prevent the tyre from moving in relation to the rim.

The disadvantage of the known apparatus is, however, that the guide means have to be provided in duplicate, while the movement of the guide means has to be synchronized, requiring costly driving gear. Also, it is not certain that the innertube cannot move in relation to the rim, so that the valve may be pulled into the rim askew.

It is the object of the invention to remove the above disadvantages and to that end the guide means are moved in one direction during placing and the innertube is, with respect to the rim, clamped near the valve.

This ensures that the tyre is drawn along the guide means without displacement of the innertube with respect to the rim, which displacement would result in the valve becoming askew.

In another improved version of the invention the guide means are, after having travelled more or less over the entire circumference of the rim so that the edges of the outer cover are positioned between the legs of the

rim, moved over a short distance in opposite direction along the tyre.

This relieves the tension developing in the inner¬ tube or in the outer cover resulting from the guide means being drawn along the tyre. This ensures that after the guide means and tyre vice have been removed, the innertube and/or outer cover do not after all cause undesirable non- alignment of the valve.

In another improved version of the invention the innertube is during fitting pressed between the edges of the outer cover with the aid of a roller, which roller is withdrawn just before placing between the edges of the tyre is completed.

This simple measure prevents that the innertube becomes lodged between the edges of the outer cover and the rim, and that it becomes damaged.

In a further improved version of the invention, after the innertube and the outer cover are clamped, the tyre is placed between guide means engaging on both sides of the outer cover.

This is a simple manner for placing a tyre wherein the guide means are firmly positioned and the tyre is gripped at both sides.

The invention also concerns a tyre placing appar- atus for carrying out a method in accordance with the invention comprising a foundation having a rotatingly driven turn table, a rim vice mounted onto the turn table, as well as guide means connected with the foundation, wherein the turn table is provided with a tyre vice for fixing the tyre in respect to the rim.

By mounting a tyre vice onto the turn table a simple and efficiently operating tyre placing apparatus is provided.

The invention is elucidated in the now following description of an embodiment with reference to a drawing in which:

Figure 1 shows a schematic side view of the tyre placing apparatus in accordance with the invention, wherein Figure IA shows the position of the turn table in

respect to the guide means during placing of the tyre, and Figure IB shows the movement effectuating placement of the rim and tyre between the guide means.

Figure 2 shows a schematic front view of the tyre placing apparatus of Figure 1, while also showing the position of the rim and tyre.

Figure 3 shows a perspectivic detail of the rim vice and the tyre vice of the tyre placing apparatus of Figures 1 and 2. Figure 4 shows a detail of the rim vice of the tyre placing apparatus of Figures 1 and 2, showing also the position of the rim and tyre.

Figure 5 shows schematically the drive of the rim vice of the tyre placing apparatus of Figures 1 and 2. Figure 6 is a schematic side view of the tyre vice as shown in detail in Figure 3, showing also the position of the rim and tyre.

Figure 7 shows the cross-section VII-VII of Figure 6, omitting the rim and tyre. The corresponding parts in the various Figures are always indicated by corresponding reference numbers.

Figure IA shows a tyre placing apparatus 1 in which a turn table 2 is driven round a rotation axis 4 by a gear box 3. The gear box 3 is mounted on a swivelling arm 5 and a middle section 10 of the turn table 2 is mounted on the output axis of the gear box 3. The vertical frame 8 is joined to a horizontal frame 9 standing on the ground. To the vertical frame 8 brackets 22 are attached which are provided with control knobs 23. The control box 24 houses the controls for the tyre placing apparatus 1.

The swivelling arm 5 having a point of rotation 6 is mounted in the vertical frame 8 and by means of a lift cylinder is able to travel a limited distance up and down, so that the turn table 2 is in a loading position 26 (see Fig. IB) when the rotation axis 4 is at its lowest and in a placing position 25 (see Fig. IB) when the turn table 2 is at its highest. The embodiment shows the rotation axis 4 which can swivel round rotation point 6 and when at its highest, is more or less horizontal. However, embodiments

are also feasible, wherein the turn table 2 can be moved in a straight line up and down, or wherein the direction of the rotation axis 4 in its various positions differs from the one shown here. In the middle section 10 two guide rods 11 are mounted such as to point into four directions at right angles to each other, along which guide rods a carriage 12 can slide with an adjusting strip 13 attached to it. The carriage 12 is provided with a rim support 1 . To an upper frame 16, which is connected to the vertical frame 8, a roller frame 15 is adjustably attached in such a manner that it is movable by means of an adjusting screw 17 in a direction A toward and away from a rotation axis 4. On the roller frame 15 swivelling arms 19 are provided at a rotation point 18, each swivel arm 19 being provided with a guide roller 20. The swivel arms 19 can be moved by means of a clamp cylinder 21.

Figure IB shows how the cylinder 21 separates the swivel arms 19 in order to allow a rim to be placed on the rim support 14 between the rollers 20, by moving the turn table 2 in a direction B from the loading position 26 to the fitting position 25. By means of the cylinder 21 the rollers are moved toward each other again so that they push against a tyre which is placed in the rim. Figure 2 shows the tyre placing apparatus 1 with a rim 27 and a tyre 28 placed in the tyre placing apparatus 1, wherein the rim 27 is clamped by separating the four rim supports 14 outward. The spokes 37 (see Figure 4) of the rim 27 rest against the spoke supports 29, while the four rim supports 14 always come between two spokes because the number of spokes on most tyres is made up of multiples of four.

Figure 3 shows a tyre vice 30 integrated in the rim support 14, onto which the rim 27 may be clamped by means of a supporting surface 31. The tyre vice comprises a rear bracket 35 and a front bracket 36 which are movable by a cylinder 34, so that the tyre 28 is clamped between the front bracket 36 and the rear bracket 35.

The tyre placing apparatus 1 operates as follows: the turn table 2 is brought into the loading position 26 by means of the lift cylinder 7 and the rim 27 is clamped onto the turn table 2 by resting the spokes against the spoke supports 29 and by simultaneously separating all four rim supports 14 outward in a manner discussed below, so that the rim 27 is fixed. By moving all four rim supports 14 simultaneously the centre of the rim 27 is brought into the centre of the turn table 2, thus keeping deformation of the rim 27 at a minimum. Subsequently the edges of part of the circumference of the tyre 28 with innertube (not shown) are placed between the legs 47 (see Fig. 4) of the rim 27.

The rim 27 is placed onto the rim supports 14 in such a way that a valve hole (not shown) is at the top. When the tyre 28 is placed it hangs vertical and by immediately placing the valve of the tyre 28 into the valve hole, the tyre 28 hangs as a matter of course along the rim 27. Then the valve of the innertube is pushed through the valve hole of the rim 27 and, if necessary, such as with a Woods valve, the valve is closed by screwing in the non-return valve. Then the innertube is inflated slightly, making it more or less ring shaped so that the outer cover can be placed around it. Also, as for instance with a Schrader valve, the innertube may first be inflated slightly and be placed into the outer cover. This is possible because the valve with a built-in non-return valve can easily be pushed through the valve hole.

After placing the tyre at the position of the valve between the legs 47 of the rim 27, the innertube and the outer cover are fixed in relation to the rim 27 by means of the tyre vice 39 such that they will not become displaced in relation to each other in the direction of the rim, which displacement could cause the valve to protrude through the rim askew.

The turn table 2 is subsequently brought into the placing position 25 and the guide rollers 20 are pressed against the tyre 28, while the tyre 28 is more or less supported by the rim 27. The turn table 2 then rotates

round its axis in a direction C and the guide rollers 20 push the tyre 28 between the legs 47 of the rim 27. It is possible, for instance, to have several sets of guide rollers 20, with a first set of guide rollers 20 exerting a tensile force on the tyre 28 due to an adjustable brake being mounted in the guide rollers 20. A second set of guide rollers 20 can push the edge of the tyre 28 above the legs of the rim 27 and a third set of guide rollers 20 can force the edge of the tyre 28 between the legs 47 of the rim. The above-mentioned tensile force is necessary for pulling the tyre 28 taut round the rim 27, thus providing some room for pushing the final piece of tyre 28 over the legs of the rim 27.

By mounting the guide rollers 20 on hinged swivel arms 19 and by having opposite rollers 20 always moved by the same clamp cylinder 21, the pressing force of opposite rollers 20 are equal. The centre of the rim 27 is always substantially positioned in the centre above the rim sup¬ port 14. This results in a symmetrically distributed load on the tyre 28 and avoids deforming forces being exerted on the rim 27. It is also possible to have one of the sets of guide rollers resting on the rim 27, so that due to the rotation points 18, the force exerted on the rim 27 is also symmetrically distributed. It is possible that during placing the tyre 28 pops out of the rim or that due to the tensile force described above, it is displaced along the rim 27, which is undesir¬ able because it hampers placing. There is also the draw¬ back that an innertube in the outer cover may move so that the valve of the innertube becomes askew. To prevent this, after placing the tyre 28, it is kept in a fixed position in relation to the rim 27 by means of a tyre vice 30.

To prevent the innertube becoming jammed between the rim 27 and the outer cover 28, it is usually slightly inflated and pushed into the outer cover with the aid of a guide roller 32 and a cylinder 33. While the final piece of tyre is being placed this guide roller 32, which rests on a support, is pushed away between the tyre 28 and the rim 27 by the cylinder 33.

After the tyre is placed round the rim 27 through the rotation of the turn table 2, whereby the tyre 28 has been forced between the legs 47 of the rim 27 by the guide rollers 20, the turn table 2 is pivoted over a small adjustable angle in the opposite direction. In this way the guide rollers 20 pull the tyre 28 into the opposite direction along the rim 27, so that the extra clearance created at the location of the guide rollers 20 between the tyre 28 and the rim 27, is taken up again and the tyre 28 again fits evenly round the rim 27. The angle over which rotation in the opposite direction takes place is chosen such that no tension remains in the tyre 28, so that on removal of the tyre vice no tension is released which could cause the valve to protrude from the valve hole askew.

Figure 4 shows the rim support 14 which is attached to the carriage 12 and which can be moved along the guide rods 11 with the adjusting strip 13 placed round a roller 39. The roller 39 can rotate round an axis 38. One can also see how always one spoke 37 rests against the spoke support 29, so that the centre of the rim 27 is always placed more or less in the centre of the support surface 31 and the guide rollers 20 are also always positioned more or less symmetrically in relation to the rim 27 and tyre 28, irrespective of the width of the rim 27.

Figure 5 shows how the toothed adjusting strip 13 can be moved. The adjusting strip 13 is moved along the rollers 39 and along guide rollers 42 attached to the middle section 10. There is also an adjusting roller 41 attached to the middle section 10, which roller is provided with teeth engaging the teeth on the adjusting strip 13. By rotating the adjusting roller 41 in a direction E the carriages 12 move in a direction D. The adjusting roller 41 is rotated over a limited angle by a cylinder 40. Altering the positioning of a lever 46 in relation to the adjusting roller 41 by means of a catch or elastic pin, allows the place of the carriage 12 to be adjusted to the diameter of the rim 27.

The tyre placing apparatus 1 can easily be adjusted to rims and tyres of different diameters and widths by manually adjusting the rim support 14 and the roller frame 15 (see Figs. 1 and 2) in the manner described above. The adjustments to the guide rollers 20 necessary for the dif¬ ferent tyres such as, for instance, the braking force that a roller set exerts on the tyre, can also simply be adjusted manually.

Figures 6 and 7 show the tyre vice 30 wherein the rear bracket 35 is moved in a press-on direction F by the cylinder 34, wherein a guide rod 43 can move in a bearing bush 44 provided in the rim support. The linear movement of the rear bracket 35 is converted by a lever 45 into a tilting movement G of the front bracket 36. The tyre placing apparatus 1 may, of course, be provided with means to inflate the innertube with air, whereby a small amount of air is pumped into the innertube before placing and the tyre is brought up to pressure after placing. Automatic supply and discharge of rims, tyres and wheels is also feasible.