DE2442401A1 - METHOD OF APPLYING A TREAD TO A TIRE - Google Patents

Description

PATENT LAWYERS

MANITZ, FI NSTERWALD & GRÄMKOW

Munich, the - "* ^SEP · P / Sv - K 2012

KENTREDDER LIMITED

Longueville, St. Savior
Jersey, British Channel Islands

Method of applying a tread to a tire

The invention relates to the application of a tread to a tire, for example a pneumatic tire, wherein either used tires with a new tread or the treads are applied to new tires.

Such processes are also called retreading and, in particular, tire soling.

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The terms tread and R _e ifen, as used here as being generic, the Vergchleißoberfläche or the carcass or the carcass is meant a tire assembly made of natural rubber or synthetic rubber.

It has already been proposed to manufacture a tire assembly or to provide it with a new tread, by preparing a band-shaped tread in a mold, so that the desired tread pattern or profile results; then the band-shaped running surface is applied to a prepared (for example roughened and aligned or centered) carcass of a tire applied. The tread tape can be vulcanized before it is applied Carcass is applied. Between the carcass and the tread band, a binding material such as unvulcanized rubber; Pressure and / or heat can be used to set the binding material and the tread tape with the tire carcass to unite. The pressure can be generated and brought into effect in different ways; for example can placing an air bag with the tire carcass; the Air bag is inflated to press the carcass outward against the tread band while it is in a mold is held. It is also possible to arrange the tire carcass and tread band in layers between two air bags in a relatively large shape and then this

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Inflate bags around the tread tape and the tire carcass to press against each other (this method is particularly suitable for radial tires). In the floating British Patent applications No. 34080/71 and No. 48368/71 become such Procedure described.

The invention is based, inter alia, on the object of a new method and a new device for applying a Creating tread tape on a tire carcass producing a tire that has improved performance; In particular, this tire shows improved wear properties, so that it has a longer service life.

The invention provides a method for applying a tread to a tire carcass, in which a preformed Tread is arranged in strip form on the carcass, at least the wear surface of the tread in is compressed in a direction parallel to the longitudinal Is the axis of the strip and wherein the tread is connected to the carcass; the compression is maintained, while the tread is bonded to the carcass, thus reducing the wear surface of the ultimately obtained Unit remains in the compressed state.

According to a preferred embodiment, the compression is carried out in such a way that the circumference of the wear area is shortened by at least 0.5%, and in particular 1 # to 10 #; rschleißeigenschaften best available V _e arise

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with a shortening from 1 # to

The tread band can be formed from any conventional material such as that used in the manufacture of tires is used; this includes, for example, natural rubber or synthetic rubber (including plastics such as polyurethane). If the tape is made of rubber, it is essential that it is made prior to application on the carcass should be vulcanized, as this is for an optimal improvement of the wear properties of the after of the present invention is necessary.

The tread strip can be prepared, for example, as an annular band that is manufactured in a form whose radius is designed so that the annular band is a little too large for the carcass. According to the present invention the annular band is then compressed and bonded to the surface of the carcass while it is compressed in it State is maintained. According to a preferred embodiment, the annular band is on its inner Surface coated with a solution of a binding agent (for example a non-vulcanized rubber), while a thin layer of cushion rubber is placed between the tape and the carcass, on which a suitable binder is applied has been applied; then pressure is generated to press the annular band against the carcass while

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the radius of the annular band is reduced so that there is compression of the tread band.

A pressure that is generated by a fluid medium can be used to apply the tread band to the carcass to muster; z. B. the combination of tread and carcass can be supported by an inflatable container (such as an air bag), which in turn is surrounded by a rigid frame is surrounded so that the pressure exerted on the tread-carcass assembly is controlled can be by controlling the inflation process and in particular the size of the inflated airbag. As alternative for this purpose, a clamping device, for example a glipring, of the type which is also referred to as "Jubilee", used to compress the tread tape onto the carcass.

It is also possible to use the tread band, if necessary together with the cushion rubber strip, (in the compressed state) to be connected with a non-expandable intermediate structural strip so that the tread is held in the compressed state will; the combination of tread and spacer strip is then applied to the carcass.

According to a further preferred method, if a preformed annular tread band is used, this be made in a mold in a conventional manner; the

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Tread tape can then be compressed into another shape that is smaller in diameter than the first shape while it is held in the other shape, while the carcass is being applied to it and while the connection is being made. This procedure is special Well suited for radial tires that are to be provided with a new tread, as there is no stretching of the Requires tire carcass, which can only be carried out with difficulty or not at all in such tires. Farther it is possible to use an adjustable shape whose radius is reduced, for example by mechanical means can be.

According to an alternative method, instead of a preformed annular band, a strip of a band-like band can be used Tread material are used. The strip is shaped as a curved strip with a radius of curvature that is smaller than that of the carcass. This results in the following: If the strip is applied to the carcass, it becomes his outer or wear surface compressed relative to the inner or bond surface. In this case it should be aimed at to form the strip so that it has a non-expandable along or near its inner surface Contains reinforcement strips so that when applying the strip on the carcass the binding surface of the strip is not under tension.

This procedure can also be used when a

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g, for example a tire for an agricultural Commercial vehicle to be provided with new studs. In this pail there is a stud that points to a certain Part of the surface of a tire carcass can be applied is to be formed with a radius of curvature smaller than that of the surface to which it is to be applied. In this case too, a reinforcement strip should be installed near the binding surface of the cleat.

It is intended to provide an annular tread band according to the present invention Invention are applied to a tire carcass, so the tread band can be in an annular shape with smaller Diameter (as mentioned above) are introduced, after which the tire carcass is inserted into the interior of the tread band will. This can be achieved by spreading the beads of the tire carcass apart so that their circumference is decreased. In practice, however, it has been found that the spreading apart, especially in radial tires of the beads cause a single, large, inward turn or fold to form in the carcass can, which can only be eliminated with difficulty, if the tire is in the mold; such a crease usually results in a defective end product when it is still present during the entire vulcanization process. A similar problem can occur, but to a lesser extent, when compressing the tread band in the smaller diameter mold; occurs in this case

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inwardly directed curl or fold, so it can be achieve uniform compression with difficulty.

The present invention provides a device with which this inward deformation can be avoided occurs; this device can be adapted so that the band-shaped tread is evenly compressed in the mold will.

The present invention provides a device having a tire shape having an inner, annular surface, to hold a belt-shaped tread; facilities are provided at certain intervals around the perimeter of the mold, to prevent a tire carcass or tread band introduced into the mold from hitting the inner surface touch in places where these facilities are located; the bodies can be taken out after the Tire carcass or tread band arranged in the mold have been so that the tire carcass or tread band then exactly against the entire inner annular surface the shape.

The facilities can be a sequence of pairs of holes (e.g. 6 pairs) equally spaced extending through the side walls of the mold and having corresponding rods, which can be pushed through any pair of holes so that the rods are spaced from the inner, annular upper

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surface of the form are arranged. If the rods are in the designated places in the corresponding pairs of holes, the tread band is thus arranged in the form, so that instead of a single large pallet, there is a small, after result in inwardly directed folds or twists (e.g. 6); then the rods are taken out so that the small gaps can be easily removed and the tread tape can be compressed evenly.

The following is also important: After the tread band has been arranged in the mold in this way, you can the rods are reinserted through the corresponding pairs of holes, and then the tire carcass can be put into the mold are introduced, where they also have a corresponding number (for example 6) of small, inwardly directed turns or wrinkles that form after removal of the rods can also be easily absorbed or eliminated. In this way an optimal contact of the binding surfaces can be achieved of the tread band and the tire carcass can be achieved.

In the method according to the invention can (with or without use the special device just described) the connection of the tire tread to a wheel or carcass be carried out under the action of heat. This can be done by the pressurized arrangement that the tread and the carcass unfilted, placed in a heating chamber will. If a metal mold is used, it can be used directly

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exposed to heat, which is then transmitted to the sanitary napkin surface.

Generally, in the present invention, the circumference of the 'tread band is _{reduced by at least 0.5 ^ 5} in a preferred embodiment 1 to 10 #, by being compressed by a force applied to it in accordance with the present invention.

The essential feature of the present invention is therefore that the wear surface of the tread band is under the influence of a compressive force. This is usually achieved particularly easily when the tread band is compressed over its entire thickness; however, this is not essential, in particular then not if the tread band is of considerable thickness. It is only essential that the wear surface (the surface, which rests on the surface of the road) is compressed in the specified manner.

The invention is described below on the basis of exemplary embodiments with reference to the accompanying schematic drawings explained in more detail.

Show it:

Pig. 1 a section through a mold with a positioned, compressed, pre-vulcanized

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nized tread tape;

2 shows a section through a mold with a tread band and a strip-shaped one Intermediate layer, these parts being arranged so that they form the carcass a tire can accommodate;

Fig. 3 is a section through a conventional mold comprising a tread band and includes a radial tire;

Fig. 4 is a cross-section through a mold. Which is provided with means to to facilitate the insertion of a Güntel tire;

Figures 5 and 6 are sections through the mold according to Figure 4, showing the introduction of a radial tire;

7 shows a partial cross-section of a tire carcass, which is suitable for a tire for agricultural vehicles;

FIG. 3 shows a cross section through a cleat which extends onto the carcass shown in FIG.

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can be brought; and

Pig. 9 a A _u devour a tire whose tread segments, so each section, has been applied. ¹

1 shows a tire carcass which is to be retreaded, that is to say in particular to be provided with a new tread; this operation is also referred to as'! soling ¹¹ . The tire carcass is roughened down to a size which is suitable for a smooth, simple, undivided ring shape 1 and corresponds exactly to the size of the ring shape. A pre-vulcanized belt-shaped tread 2, the circumference of which is approximately 2 # longer than the circumference of the mold 1, is then prepared. The pre-vulcanized tread tape 2 is then placed in the shape as shown in Fig. 1 so that it is compressed evenly over its entire surface. Since the tread band 2 is oversized, it can be more easily compressed in the mold 1 if a lubricant, for example a silicone rubber, is distributed around the surface of the mold 1, for example by spraying.

In the remaining (not shown) operations of the method a layer of binding material, with or without a rubber or adhesive solution, is applied to the roughened surface the carcass or on the inside of the tread band 2 (according to a preferred embodiment on the roughened

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th surface) applied while the beads of the tire are spread apart to reduce its diameter, so that the tire is on the inside of the tread belt 2 can be inserted into the mold. If the beads are released, the prepared connective surfaces are in Brought into contact with each other, being exposed to the action of heat and pressure, to keep the bond secure and secure to make tight. This method can be used with diagonal tires or radial tires.

A very similar workflow can be used when installing an intermediate strip. Like in Pig. 2 As shown, the tread band 2 is similarly compressed in a mold 1, and then becomes an inextensible one Intermediate structural strips 3 connected to the tread band, for example glued. The intermediate building strip 3 ensures that the tread band 2 is held when pressed together will. A layer of binding material 4 is then applied to the. Intermediate structural strips 3 applied, after which a tire carcass is introduced into Form 1. In this case the roughened tire carcass has the same diameter as the intermediate building strip 3 · If this method is applied to a diagonal tire, the tire is converted to a radial tire.

In the method shown in Figures 1 and 2, the necessary pressure, which is used, for example, to the To support binding effect, generated by means of an airbag

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inflated in the tire carcass in the mold; the exposure to heat can be done by the entire The mold is placed in an oven; alternatively, a mold having internal heating elements can be used.

When the prepared tire is on the compressed tread band is placed, there is a risk that air is trapped between these two parts. This can can be avoided by providing Gajis outlet holes, which run through the thinner parts of the vulcanized tread; The air can then escape through these holes step out.

4, an annular mold 21 is channeled to receive a tread band 22. The sidewalls of the mold protrude beyond the tread band 22 and contain a series of pairs of holes 7, 7 ¹ spaced around the circumference. In each pair of holes 7, 7 'there is received a rod 8 which extends through the mold at a distance from the inner (the running surface receiving) wall of the mold.

In Fig. 3 a mold 21 is shown which contains a tread band 22, but wherein the rods 8 are not yet are in their positions; furthermore, the mold 21 has received a carcass 5 of a radial tire. A big one, after inward winding or fold 6 has become in the tire

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Carcass 3 formed; this fold can only be made with large. Remove difficulties and cause the finished tire to have a relatively weak area.

Referring to Figures 5 and 6 21 assumes a generally similar form to a tread band 22 and six rods 8, the Clen each i ⁿ it is intended positions. The tire carcass 5 _5, which is arranged in the mold 21 with the rods 8 in their positions, now forms six small folds 9 instead of a single large fold or turn. If the rods 8 are now removed (FIG. 6), then the small folds or turns are easily absorbed in the mold and disappear, so that a good seal of the tread band 2 on the carcass 5 is now possible. .

7 shows a section of a tire carcass 10 which is suitable for an agricultural utility vehicle is. The radius of curvature of the outer surface of this portion of the carcass is r. Figure 8 shows a tunnel 12 to be applied to that portion of the tire. The cleat has a pre-vulcanized rubber: -

1 1

strip with a radius of curvature r, where r is smaller than r. The wear surface of the cleat is at indicated; near the other surface 13 is one Reinforcement 1A- (for example, a wire mesh) in the Rubber provided so that the cleat at this point is non-expandable. "

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The cleat 12 is installed over the tire section 10; as its radius of curvature is increased, the wear surface becomes of the tunnel brought under the influence of a force that compresses them.

Figure 9 shows a tire carcass 5, the tread in sections should be renewed, as it is z. B. in pending British patent application, aratl. British file number J4-395 / 73 of the applicant is described. A number of strips, for example four, are prepared to be applied to the crown of the carcass so that they come together form a complete running surface, which can have a smooth, even wear surface for certain purposes. A strip 23 (Fig. 9) is formed with a radius of curvature which is smaller than that of the tire, so that the Strip, in the figure the strip 24, has a compressed wear surface.

It has been found that by means of the present invention #the lifespan of a tire compared to the Tires can be increased very much where the soling is done in the traditional way. That is why pneumatic tires, which have been provided with a new tread according to the present invention, are used much longer than tires made in a similar manner, but without compressing the tread surface with a new tread have been provided; these tires can be used even longer than new tires; which are produced in a conventional way

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have been presented.

- patent claims -

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Claims (16)

Patent claims j1. ^ Method of applying a tread to a Tire carcass in which a preformed tread is arranged in strip form on the carcass and with it is connected, characterized in that at least the wear surface of the tread (2, 12, 22, 2 $) in one direction which is parallel to the longitudinal axis of the strip, maintaining the compression is while the tread (2, 12, 22, 23) is connected to the carcass - (5), and the wear surface the final unit remains compressed. 2.Verfahren according to claim 1, characterized in that the compression is carried out in such a way that the wear surface of the tread (2, 12, 22, 23) is in front the connecting step is shortened by at least 0.5 ^. 3. The method according to claim 2, characterized in that the wear surface is shortened by 1 to 10 #. 4-. Method according to claim 3? characterized in that the surface is shortened by $ 1 to $ 6. 5. The method according to any one of claims 1 to 4, characterized in that that the preformed tread strip 509 811/0357 (2, 22) is designed as an annular band. 6. The method of claim 5, wherein the inner surface of the annular band and the outer surface of the carcass are coated with a binding material and a layer of cushion rubber is disposed between the annular band and the carcass, characterized in that that the pressure is exerted on the wear surface of the tread, around the annular band (2, 22) to press against the carcass (5) while reducing the radius of the annular band (2, 22), whereby the tread band is compressed. 7. The method according to claim 6, characterized in that the pressure of a fluid medium is used to compress the tread band (2, 22). 8. The method of claim 5, wherein the inner surface of the annular band is coated with a binding material, characterized in that the annular Band (2) in the compressed state is connected to a non-expandable intermediate structural strip (3), wherein then the combination of tread and intermediate strip (5) is connected to the carcass (5). 9. The method according to any one of claims 5 or 8, in which the annular band in a shape with a certain - 20 509811/0357 -20- 2ΑΑ2Λ01 th diameter is formed, characterized in that the band (2, 22) in a further shape (21) with a smaller diameter than the first shape is compressed, while it is held in the other shape (21) will while the connection. . the tread is carried out. 10. The method of any one of claims 1 to 4, wherein the preformed tread is in the form of a curved strip has, characterized in that the strip (12, 23) has a radius of curvature which is smaller than that of Is the carcass surface to which the strip (12, 23) is to be applied, so that the wear surface of the strip, which is the convex surface of the strip (12, 23), is compressed when the Strip (12, 23) is connected to the carcass (5). 11. The method according to claim 10, characterized in that the strip (12) is designed so that it is longitudinal or in the vicinity of its concave surface (13) contains an inextensible reinforcing strip (14) so that when applying the strip (12) to the carcass, the binding surface (13) of the strip is not under tension stands. 12. The method according to claim 10, characterized in that the strip (12, 23) on the carcass (5) in a direction - 21 50981 1/0357 -21- 2U2401 device is applied, which is parallel to its circumference. 13. The method according to claim 12, characterized in that a plurality of tread strips (23) are applied next to one another around the tire carcass (5), so that a complete running surface is created. 14. The method according to claim 10, characterized in that the strip (12) onto the carcass in one direction is applied, which is transverse to its central circumferential axis. 15 · Method according to one of claims 13 or 14, characterized characterized in that each tread strip (23) has a smooth wear surface. 16. Device for carrying out the method according to one of claims 1 to 1.5 with a tire mold which has an inner, annular surface for holding a tread band, characterized in that at intervals around the circumference of the mold (21) devices (7, 8 ) are provided which prevent a tire carcass or a tread band to be introduced into the mold (21) from touching the inner surface at the points where the devices (8) are located, these devices (8) being removable after the R _e ifen carcass, or the tread band in the form 509811/0357 -22- -22- 2U2401 (21) has been arranged so that the tire carcass or the tread band then exactly against the entire inner annular surface of the mold (21) can abut. Device according to claim 16, characterized in that the devices (7, 8) have a sequence of pairs of holes (7-7 ') which run at a distance from one another through the side walls of the mold (21) and have corresponding rods (8) , which can be pushed through each pair of holes (7, 7 ¹ ), so that the rods (ß) are at a distance from the inner, annular surface of the mold (21). 509811/0357 Blank page