The invention relates to a roller device for crumbling stripes of carcasses of worn tires and recovering steel wires, fibres and warps separated from rubber grains.

5 At the present state of art the machines for the recovery of rubber from worn tires are based upon the cooling principle at very low temperature. Such method is the socalled cryogenic method. Otherwise they make use of conventional shears for cutting to small pieces as little

10 as possible. However, such shears do not separate from rubber the warps and the steel wires which form the carrying structure of the tire. Both methods have very high processing cost due to the further machining requested to completely separate rubber from the other

15 materials of the tire.

The present invention seeks to provide a solution to solve in an extremely easy and complete way the problem of crumbling and separating wires from warps in only one

20 passage of the tire through the nip formed by a roller and a counteracting member. This is achieved by the described device in which the material is passed between a suitably shaped roller and a counteracting member which can be a stationary plane provided or not with balls in

? ^ the counteracting area. The basic effect of such roller along with the counteraction of the above-mentioned plane is an uniform compression which can crumble an elastomer material such as rubber like a concrete test piece in a

compression test machine. Thus rubber is reduced in grains of different size separated from the other component materials such as warps and the steel wire lenghts included in the carcass of used and worn tires. 5 It should be pointed out that the only preliminary treatment to be carried out on such carcasses is to cut them in stripes by a common shear for allowing them to be inserted into the device.

The solution with a counteracting stationary plane is 10 extremely effective, however, it was sperimentally found that by eliminating the stretch of the material against the stationary plane or a part thereof, the machining times are considerably reduced.

To this purpose, in a second embodiment of the invention 15 the material is moved by rotating surfaces. According to such embodiment the device essentially consists of two rollers each having a side edge or shoulder. The two rollers with the relative edges are juxtaposed to each other with parallel axes so as to form a nip or a passage 20 - between each other having a rectangular section closed at .. the four sides of the rectangle. If a stripe of the carcass of a worn tire is inserted between the two rollers and if for example the upper roller is rotated, the stripe is confined between the two side edges or 25 shoulders so that its thickness is considerably reduced, and due to the high pressure the stripe is then crumbled in grains. Also the steel wire and the warps are separated from the wrapping rubber due to such considerable pressure and the different elasticity of the ™ materials.

The result of such compression and the successive

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crumbling is a granular material containing small pieces of steel wires, warps or loose wires or fibers and rubber grains of different size. By easily separating the three mentioned materials obtained by crumbling stripes of worn tires, it is possible to recover the three materials at low cost and to use them again for industrial purposes. As many pairs of rollers as desired can be provided in a crumbling machine for the treatment of stripes of worn tires, the distance between the axes of the two rollers being chosen according to the granulometry desired by the user .

The present invention will be described in detail with reference to the accompanying drawings which show by way of a non-limitative example the two above-mentioned preferred embodiments. In the drawings:

Fig. 1 is a front section view of the device according to a first embodiment _>

Fig. 2 is a longitudinal section view along the line A-A of Fig. 1;

Fig. 3 is a detail of the compressed material in which the uniform distribution of the load all over the periphery can be seen;

Fig. 4 shows a variant in which balls projecting from the counteracting plane are provided;

Fig. 5 is a front view of a second embodiment of the Invention: and

Fig. 6 is a side view of the embodiment of Fig. 5>

The following numerals indicate the several components of the device of the invention and the steps of treatment of the material :

1 - compression roller provided as a whole with two shoulders 1A and IB of such a diameter as to be placed upon or cover the edges of plane 2 ;

1A and IB - side shoulders of roller 1 having the function of avoiding that material 3 can be laterally discharged during the compression between the body of roller 1 and the counteracting plane 2 ;

1C - generic drive shaft for rotating roller 1 which is connected to a suitable geared assembly driven by an electric motor or an explosion engine or the like;

2 - counteracting plane provided between the two shoulders 1A and IB of roller 1;

3 - generic stripe of a worn tire compressed and shown in section, said stripe containing lengths of steel wire 7 , rubber grains S, synthetic threads or fibers of warps 9

- support frame or carrying structure made of sheet or high-resistance section bars of steel;

5 - direction of rotation of the roller or rollers in this example;

6 - generic cover placed on frame 4 ,'

7 - lengths of steel wire of a tire carcass;

8 - rubber grains of several size crumbled in such. device ;

9 - pieces of synthetic warps or threads or fibers obtained from the crumbling of tires and originally contained in the tire;

10 - arrows indicating the forces and their directions towards the stripe of tire which is crossing the restricted section between roller 1 and plane 2 while being compressed;

11 - balls placed in a row parallel to the generatrix of roller 1 in the section between roller 1 and plane 2;

12 - cover and support containing balls 11;

L - arrows indicating the direction of movement of the material .

Fig. 1 shows the main section of the device of the present industrial invention from which the form of the compression roller provided with two shoulders 1A and IB having a diameter such as to cover the short sides of the

counteracting plane 2 can be seen. Material 3 , i.e. the stripes of worn tires, is forced by the rotation of roller 1 in the direction of arrow 5 to pass between roller 1 itself and plane 2 while being sideways confined between shoulders 1A and IB. Therefore, a strong, as high as desired, compression is provided which is above all evenly distributed on the four sides of material 3 - Such compression causes a complete crumbling of the rubber and the removal of foreign bodies, as already described, i.e. lengths of warps, threads and steel wires, all of them well separated from the rubber.

The longitudinal section of Fig. 2 shows a number of balls like those of Fig. 1 having the function of carrying out different compressions of the material during the movement of the latter in the direction of the two arrows, such different compressions being carried out by progressively reducing the passage section. Fig. 2 shows in particular the reduction of the gap P between compression roller 1 and the counteracting plane 2 as the materials move to the output of the device. As can be seen, PI is larger than P2 and so on up to PN which is the smallest gap among all sections. At the output of the device the pieces produced by the crumbling action of roller 1 and plane 2, i.e. lengths 7 , rubber grains 8 and warps or threads 9 , are shown.

Fig. shows the compression section where arrows 10 indicates the uniform distribution of the compression load along the periphery of the section, such load causing the rubber to be completely crumbled and the

threads, fibers, warps and broken steel wires to be removed.

Fig. 4 shows a number of balls placed along a line parallel to a generatrix of roller 1 in the compression section and projecting upwards from plane 2. The balls designated in that figure by 11 are inserted from the lower side of plane 2 and held in their positions by a generic cover 12. Balls 11 cause the material to move at uniform speed along the restricted section so that also the compression of the processed material is in that case practically uniform. Otherwise, if balls 11 are not provided, material 3 is also subjected to a tensile stress perpendicular to the section of Fig. 3 and due to the contact between material 3 and stationary plane 2.

The effect of such tensile stress due to the slippage of the material on plane 2 promotes the removal of the foreign bodies from rubber . - Therefore a combination between roller 1 and plane 2, and between roller 1 and balls 11 assures a final result of very good quality and provides as end product nearly clean steel wire lengths, rubber grains of different (in any case very small) size, and warps or the threads thereof well separated from the rubber.

The gap (PI, P2, ... PN) is not a determinant feature of the system formed of roller 1, shoulders 1A and IB and the counteracting plane 2 with or without balls 11. Determinant are, however, the two shoulders 1A and IB which have to enclose the restricted section at the sides of plane 2 in order to allow the stripes of the worn

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tires to be evenly compressed.

The alternate embodiment of Figs. 5 and 6 can be applied also in combination with the assembly formed of roller and stationary plane in order to shorten the processing time. In those figures the same numerals designate the same components as in the preceding embodiment. In Fig. 5 the stationary plane is replaced by a second roller 2' rotatable about its own axis, and each roller i _s provided with an edge or shoulder 1A and 2A. respectively. The two rollers rotate in the direction 'of arrow 5 . thus causing a stripe of tire to be compressed and the section thereof to be reduced. Numerals 3 indicates the materials to be crumbled and also the small section between the two rollers 1 and 2' between which the maximum compression according to arrows 6 takes place. Such compression is perpendicular to the four sides of section 3 so that no elastic recovery typical of such materials is given.

In such embodiment of the present invention particular reference should be made to the specific form of rollers 1 and 2 ' and to their relative positions in order to achieve the basic effect of the device, i.e. the above-mentioned uniform compression on the four sides of the rectangular section 3 which is determinant both for the crumbling of the stripes of worn tires and for the removal of the steel wires and the warps rom the rubber .

Fig. 6 shows a general side view illustrating the effects of the particular machining, i.e. the end products 7 , 8 and 9 of the crumbling of worn tires.

As for PI, i.e. the minimum gap between rollers 1 and 2' , it is necessary to point out that such gap may be varied as a function both of the number of rollers which have to be mounted in a crumbling machine and above all of the desired granulometry of the rubber at the end of the crumbling operation.

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