DE1270272B - Reinforcement insert made of at least two cord fabric layers embedded in rubber - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

B29h

German class: 39 ate- 17/14

Number:
File number:
Registration date:
Display day:

P 12 70 272.6-16
February 14, 1963
June 12, 1968

The invention relates to a reinforcement insert made of at least two cord fabric layers embedded in rubber, the threads of which cross each other in the adjacent layers, for endless bands to build up of pneumatic tire blanks with a cord angle 5 at the zenith of 5 to 30 °.

It is known to let cord fabric layers follow one another to build up a pneumatic tire blank, in which the cords run at an angle of more than 45 ° to the central circumferential plane. the Layers are cut at an angle to the longitudinal edge of a cord, which corresponds to the »complement angle« corresponds to the cord angle in the blank. It is recommended to use this angle to choose with 50 ° and less. When later crowning to a cord angle at the zenith of 5 to 30 ° the cords approach each other to such an extent that the rubber that connects them displaces them becomes what happens with considerable expenditure of force and to considerable tension in the structure of the blank leads. In addition, the shear movement of the cords, which are in the successive Crossing layers, made difficult by the leakage of rubber between the cords and is hindered, which can also cause distortions in the structure.

It is also known to use the reinforcement insert of a tire with a cord angle of less than 30 ° at the zenith on a high shoulder drum to set up the blank right from the start to give a shape that approximates the shape of the finished tire.

The invention is based on the object of designing the reinforcing insert so that when it is crowned of the reinforced green tire that does not displace the rubber between the cords will.

This is achieved according to the invention in that the endless belt has a diameter which is much smaller than the outer diameter of the one used to build the green tire Tire building drum is, the cord angle of the tape is approximately the complementary angle to the for correspond to the intended cord angle at the zenith of the finished tire.

This ensures that during the process of expanding from the initial diameter of the blank to the final diameter of the finished tire, the distance between the cords is initially expanded until the shear angle of 45 ° is reached, and the intermediate rubber is stretched and the threads are reinforced during the rest of the shear movement from at least two in
Cord fabric layers embedded in rubber

Applicant:

Dunlop Rubber Company Limited, London

Representative:

Dipl.-Ing. R. Mertens, patent attorney,

6000 Frankfurt, Neue Mainzer Str. 40-42

Named as inventor:

Vernon Eric Gough,

Sutton Coldfield, Warwickshire (UK)

Claimed priority:

Great Britain 16 February 1962 (5971)

are brought closer to each other again by the same amount and the stretched rubber relaxes again. With this measure it is further achieved that the occurring in the course of the shear movement Resistance of the rubber goes back to zero after an initial increase, so that in this Relationship the finished tire has a stress-free structure, and that the squeezing of the rubber between the threads and thus prevents irregularities in the structure and the thread layer be avoided. This means that green tires for cord angles of less than 30 ° can also be used Zenit can be produced in a flat structure, but it is just as possible to have a carcass in a partially cambered To build the state on a high shoulder drum and after the endless tape has been put on camber the carcass into the shape of the finished tire.

Appropriately, the cord angle of the tape deviates by up to ± 10 ° from the angle that the Complement angle of the cord thread angle provided for the finished tire at the zenith.

In the drawing, exemplary embodiments of the reinforcement insert are shown.

Fig. 1 shows a diagrammatic representation of a Two-layer tape made of steel cables, which is used as a tread reinforcement insert is to be installed in a pneumatic tire; Parts of the tape are broken away to reveal more details;

809 559/211

sensitive carcass can be placed. To his To increase diameter, it is necessary to stretch the tape in the circumferential direction. That will be on the in F i g. The stretching device 10 shown in FIG. 2 is carried out.

The device 10 contains a roller 11 driven by an electric motor, and a second, detachable and roller 15 mounted freely at one end of arm 16.

In order to stretch the endless belt, it is used as shown in FIG. 2 shown, in the manner of a drive belt around the two rollers are placed, the electric motor is set in motion and the spindle 19 in the appropriate direction rotated to move the rollers apart and

F i g. FIG. 2 shows in a diagrammatic representation how an endless belt shown in FIG. 1 is inserted into a device is inserted in which it is to be stretched in the circumferential direction;

F i g. 3 is a perspective view of a cylindrical built up green tire, this being the endless belt according to FIG. 1 and 2 includes and axial is stepped to reveal details of the carcass;

F i g. 4 is one of the F i g. 3 similar view of the blank according to FIG. 3 after this in the guise the finished tire has been cambered;

FIGS. 5 and 6 are top plan views of a portion of the FIG. 1 to 4 shown endless belt and

show the arrangement of the ropes in the layers before 15 thus stretching the tape until it is essentially the the stretching of the tape and after the crowning has a diameter that is suitable for placing on the the carcass on which it is placed; carcass located on a building drum requires

F i g. 7 shows a second embodiment, which is confusing, which is displayed on a scale. then Reinforcement pad and is a view similar to that in when the engine is turned off and the belt is removed from the F i g. 1, an endless two-ply belt made of steel so rolls are taken.

ropes used for the carcass reinforcement Before the tape 6 a is to be attached to the tire carcass; is placed, a single tread reinforcement

F i g. 8 is a diagrammatic representation of a kung installation 24 (see FIGS. 3 and 4) made of steel cables in FIG axially cut green tire, which is placed in the essential crown area of the carcass. The ropes of the borrowed cylindrical shape and that in 25 position 24 are at an angle of 80 ° to the center-F i g. 7 includes tape shown; arranged circumferential plane of the tire carcass. Of the

The area of the carcass on which the band 6 a is to be placed is lightly dusted with zinc stearate powder, except for a narrow strip in the area of the central circumferential line of the carcass.

The tape is then, as shown in Fig. 3, placed symmetrically on the tire carcass and only in the area where it is on the narrow strip the carcass that is not powdered with zinc stearate

built. The carcass is rolled onto the carcass from a single ply 3 35 which is resting on it. It formed from steel cables embedded in rubber, which is zinc stearate on the outer surface of the belt, at an angle of 90 ° to a circumferential line again with the exception of a narrow strip in the the building drum are arranged. A pair of bead cores 4 are dusted, one on each drum, and a barrel strip 25 of unvulcanized Front side, applied to the carcass ply, and the rubber mixture is placed on the belt and Edges of the carcass ply are known in the area that is on the narrow strip on-way wrapped around the associated bead cores, which is not powdered with zinc stearate powder tet. Bead protection tapes 5 are then applied, rolled on.

and rolled up. A tread reinforcement insert 6. Sidewall rubber 26 is then applied, and for the carcass described above, an end 45 of the finished green tire is removed from the building streamless belt 6a, which is constructed in the following way: mel, into the shape of the finished tire As shown in FIG , the endless band is cambered and vulcanized in a mold. The two layers 7 and 8 of beers embedded in rubber, molding and vulcanizing the green tire formed from steel cables. In the two layers 7 and 8, in a conventional inflatable bellows vulcanizing machine, the steel cables 9 are passed through at an angle of 65 ° to 5 ° and result in a pressure as shown in FIG. 4 a circumferential line of the band 6 α, the finished tire shown 2. the ropes of one layer in the opposite one.

Direction to the circumferential line are arranged as the expands, wherein the expansion takes place in that that of the other layer. 5 shows a plan view of rubber mixture stretched between the ropes part of one side of a band 6 a in which it is instead of the scissors movement, through which initial state, whereby the two-layer band is stretched at an angle, so that the angle cut ends of the ropes 9 along the ply edges of the ropes in the ply 24 are essentially unchanged. The approximate ratio of the diameter remains. During crowning, the belt forming the run of the belt at this stage becomes the diameter, strip reinforcing insert of which it is designed to have a diameter of 1: 2 in the finished tire 60 with which it is to be on the building drum. The approximate ratio. was applied to the diameter it is in

finished tire is said to have stretched, and the rope angle of its ropes is, as in FIG. 4 and 6, reduced to 25 °. The zinc stearate powder between the carcass and ply 24 on the one hand and the belt 6 a on the other hand and between the belt and the running strip acts as a lubricant before vulcanization, around both sides of the center circumference

Fig. 9 is a view similar to Fig. 8 and shows the blank shown in Fig. 8 after it has been cambered into the shape of the finished tire.

In the case of the in FIG. 1 to 6 illustrated embodiment is a green tire 1 (Fig. 3) of a tire ^ (Fig. 4) in a conventional manner on a (not shown) cylindrical folding drum

the width of the band at this stage is equal to the width it will be in the finished tire,
measured in the axial direction of the tape or the
Tires, 2: 1.

As shown in Figure 1, the initial diameter of the tape is smaller than what it is should so that it falls on the

Gluing these parts to one another and thus a mutual influence of these parts during the To prevent shear movement of the ropes of the belt and the reduction in width of the belt.

In a modification of that in the first embodiment Reinforcing insert described are, when building a tire, with the very large angular changes are required during crowning of the tread and the tread reinforcement insert by means of pins that are inserted through the tread and tread reinforcement insert into the carcass at certain intervals along the center circumference of the tire are secured on the carcass. These pens are after removed from the tire after crowning and before vulcanizing.

If you make such a large change from an angle of, for example, 65 ° to an angle of 25 °, this means a fabric stretch of around 120% on the circumference of the tire. That's why a stretching process is sent before the tape is placed on the building drum for cambering will.

The pre-stretching process increases the diameter of the tape to the diameter the shape and at the same time connects the rubber between the adjacent ropes, so that the rubber can be squeezed again and the rope distance returned to its original value can be, if then the green tire from the cylindrical into the shape of the finished Tire is transferred.

In a further modification by means of the above-described method, two or more belts 6 a to form a reinforcing insert with more than one pair of layers are laid. It is not necessary that the final cord angle of each pair of plies should be the same as the final angle of the other pairs of plies which make up the reinforcing insert.

According to a further modification, two or more tread reinforcement layers 24 are built into the tread reinforcement insert in addition to the band 6 a. The cords in the layers are arranged at cord angles in the range from 65 to 90 °.

In a further embodiment of the reinforcing insert, the manufacture of a tire 27 (FIG. 9) containing a carcass similar to the endless belt 28 (see FIG. 7) formed from two layers 29 and 30 of steel cables Structure as the endless belt 6a in Fig. 1 is carried out by a method similar to that described in the first example. In this case, the layers of the tape 28 are cut so that their cables are arranged at an angle of 65 ° to the central circumferential plane. This angle is the complementary angle to the final rope angle of 25 ° in the crown area of the finished tire.

After the tape is in the form shown in FIG. 2 to the outer diameter of a (not shown) cylindrical building drum has been stretched, it is, as in F i g. 8 shown on the Building drum placed, bead cores 31 are placed on the end faces of the building drum, the Edges of the plies are folded around the bead cores and chafers 32 are applied. Tread and sidewall rubber 33 are then placed on the carcass, and the green tire is removed from the building drum into which in FIG. 9 shape of the finished tire shown cambered and vulcanized.

In the final state, the cord thread angles of the cord threads in the carcass have increased from 65 to 25 ° the central circumference in the crown area and changed to 60 ° in the two bulge areas.

If steel cable layers are used, the layers forming the tape can be if they are made of the cable fabric are cut off, are cut at a relatively high rope angle, as shown in FIG. 5 shows what results in each rope being cut at an angle with respect to its longitudinal direction, which closer to 90 ° than it would be if the plies were cut at the small cutting angle that was previously required when installing the plies in the tire. The ropes will thus almost severed with a cut made at a right angle and consequently the The cutting process does not expose as large a metal area at the ends of the ropes as it does when cutting underneath would be done at a small angle. The ropes are usually brass plated to make them good on the rubber adhere, and since the metal exposed when the layers are cut is untreated, between the Rope ends and the rubber surrounding them may not adhere to them. The resulting Reducing the exposed metal area allows the rope ends to be more secure to the one surrounding them Stick rubber.

Cutting the rope layers at a relatively high cutting angle can be easier than with A small cutting angle can be executed precisely because of the direction in which the rope layers are cut is at a larger angle to the direction of the ropes and therefore the probability there is less deflection of the ropes by the cutting tool. Because the layers are under one cut at a large angle is also the length of the cutting stroke required for the severing a layer of a cable car of a given width is relatively small compared to that, which is required to separate a layer from the same web at a small cutting angle.

This allows the cut to be made faster and, in some cases, can make a simple cut Guillotine shears are used instead of the usual circular knives to be pulled over the cable car will.

While in the embodiments described above, the rope layers first at an angle of 65 °, which is equal to the complementary angle to the crown angle of 25 °, it may be advantageous in some cases to cut the layers at a cutting angle to cut that is slightly larger or smaller than the complement angle of the rope angle in the finished Tire is. If the plies are cut at an angle greater than the complement, then is crowning the endless belt to the desired final crown angle is easier than in the case in which the layers cut at an angle exactly corresponding to the complement angle will. If the plies are cut at an angle smaller than the complement angle, the rope spacing in the layers in the finished tire is reduced compared to the rope spacing in

uncompromised condition of the layers, which leads to a closer agglomeration of the ropes and the surrounding area Rubber leads.

Claims (2)

Patent claims: 1. Reinforcement insert made of at least two cord fabric layers embedded in rubber, the threads of which intersect in the adjacent layers, for endless belts for the construction of pneumatic tire blanks with a cord thread angle at the zenith of 5 to 30 °, characterized in that the endless belt (6a, 28) has a diameter that is significantly smaller than the outer diameter of the Fenrohlings tire building drum used, and wherein the cord angle of the tape approximately correspond to the complement angle to the intended for the finished tire (2, 27) cord angle at the zenith. 2. Reinforcing insert according to claim 1, characterized in that the cord angle of the tape (6 a, 28) deviates by up to ± 10 ° from the angle which is the complement angle of the cord angle provided for the finished tire (2, 27) at the zenith. Considered publications:
German Patent No. 398,374;
German interpretative document No. 1093 985. For this purpose 2 sheets of drawings 809 559/211 5.6 »© Bundesdruckerei Berlin