Technical Field

The invention concerns a device for preparing rubberized fabric cord which is used in radial tyre production, where the preparation of rubberized fabric cord is performed by means of rubberizing individual fabric threads, adhesion of which is modified by plasma application.

Background Art

In the process of radial tyre production, wound overlapping belt, also called the spiral belt, as a part of the belt assembly, improves considerably the use properties of radial tyres. The wound overlapping belt is actually a strip of rubberized fabric cord of a certain width (usually of 1 to 20 mm), which is in confection lines for tyre production spirally wound onto the preceding belt layers of the belt-tread assembly. Positive effect of using the wound overlapping belt in a tyre demonstrates itself by decreasing tyre rolling resistance, increasing its highspeed performance and increasing steering performance and tyre life.

The very preparation of wound overlapping belt consists of rubberizing fabric cord and of subsequent operations. Nevertheless, before rubberizing it is necessary to treat the fabric cord chemically so, that it achieves sufficient adhesion necessary for the rubberizing process of good quality. Subsequently, the rubberized fabric cord is longitudinally slit to final width. Slitting is usually performed in two stages. Chemical treatment of the fabric cord is accompanied with considerable negative environmental effects, and it increases the total costs for wound overlapping belt preparation.

Devices, known so far, for preparing rubberized fabric cord, suitable for the wound overlapping belt production, use a three-stage production method for the wound overlapping belt. First, the fabric cord is rubberized, usually on a 4-cylinder rubberizing device. The fabric cord entering a rubberizing device is chemically adhesively modified. Adhesion is necessary for perfect rubberizing process and

the resulting qualitative properties of the rubberized fabric cord, as well as of the produced tyres. After rubberizing, the rubberized fabric cord is wound on reels which are introduced into the second stage.

The second stage consists of a further device - a slitting machine for slitting the rubberized fabric cord to a width of approximately 80 to 100 mm. After rubberizing, the rubberized fabric cord is wound on reels which are introduced into the third stage.

The reels with rubberized cord are subsequently slit in the third stage, which consists of a further slitting machine, where the slitting leads to final width of the wound overlapping belt, which is then wound on reels and subsequently used in confection lines.

A disadvantage of the above method of preparation of rubberized fabric cord for wound overlapping belt consists in higher production costs resulting from higher price of adhesively modified fabric cord, necessity of operating the respective devices, manipulation of material reels, higher energy demands, as well as negative environmental effects.

A further known device for preparing rubberized fabric cord makes use of one-stage method. The device comprises unwinding stations for individual cord threads, an extruder, a slitter and winders. Cord threads then enter the head of a transversely arranged extruder, where the strip of entering threads is rubberized. Individual cord threads entering the rubberizing device are chemically adhesively modified. Adhesion is necessary for perfect rubberizing process and the resulting qualitative properties of the rubberized fabric cord. After rubberizing, the rubberized fabric cord is slit to final width, wound on reels and subsequently used in confection lines.

A disadvantage of the above method of preparing rubberized fabric cord consists in higher production costs resulting from higher price of adhesively modified cord threads, as well from its negative influence on the environment.

A solution for this problem is a device for preparing rubberized fabric cord, where the rubberized fabric cord is prepared using direct rubberizing fabric threads by means of a transversely arranged extruder, wherein adhesion of fabric threads is modified by plasma application before rubberizing.

Disclosure of Invention

The above disadvantages of the devices for preparing rubberized fabric cord used in radial tyre production are eliminated by the technical solution of the device according to the present invention, the nature of which consists in that the device consists of a section of unwinding stations for individual cord threads, a plasma unit, a transversely arranged rubberizing extruder, a cooling unit, a longitudinal slitting machine and a section of winding stations for the rubberized fabric cord.

The section of winding stations of the device according to the present invention may include equal or smaller number of stations for winding the rubberized fabric cord up than that of the section of unwinding stations for individual cord threads.

Individual adhesively unmodified cord threads are unwound from the unwinding stations and enter the plasma unit. In the plasma unit, surface layer of the cord threads is modified using low-temperature plasma, which results in an increase of adhesion necessary for the subsequent rubberizing of cord threads. After exiting the plasma unit, the adhesive surface treated cord threads enter the head of a transversely arranged extruder, where they are rubberized by a rubber composition. The rubberized strip of fabric cord of an appropriate width proceeds to a cooling unit, where it is cooled. Subsequently, the rubberized fabric cord is longitudinally slit to final width and individual strips of the rubberized fabric cord are wound on reels at the winding stations.

An advantage of the above device for preparing rubberized fabric cord, suitable to be used as wound overlapping belt, is the fact that using it there are achieved reduction of costs of the cord, reduction of energy costs, increase in effectiveness of the production process, reduction of tyre weight, as well as positive environmental effects.

Overview of pictures in the drawing

The device for preparing rubberized fabric cord, suitable to be used as wound overlapping belt, used in radial tyre production according to the present invention, is explained in more detail in the enclosed drawing, schematically showing the device for preparing rubberized fabric cord, used in radial tyre

production, where the preparation of rubberized fabric cord is performed by means of rubberizing individual fabric threads, adhesion of which is modified by application of low-temperature plasma.

An example of invention embodiment

A device for preparing rubberized fabric cord, used in radial tyre production, consists of section 1 of unwinding stations for individual cord threads, a plasma unit 2, a transversely arranged rubberizing extruder 3, a cooling unit 4, a longitudinal slitting machine 5 and a section 6 of winding stations for rubberized fabric cord.

Individual adhesively unmodified cord threads are unwound from unwinding stations of section 1 and enter the plasma unit 2. In the plasma unit 2, surface layer of the cord threads is modified using low-temperature plasma, resulting in creation of adhesion necessary for the subsequent rubberizing of cord threads. After exiting the plasma unit 2, cord threads with adhesive layer enter the head of a transversely arranged extruder 3, where they are rubberized by a rubber composition. Rubberized strip of fabric cord of a width of 40 mm proceeds to the cooling unit 4, where it is cooled. Subsequently, the rubberized fabric cord is longitudinally slit into 4 parts with the final width, which is 10 mm in this case, in a slitting machine 5, and individual semi finished products of wound overlapping belts are wound on reels at the winding stations of section 6. Nominal speed of rubberizing was 25 m/min.

Industrial applicability

Method according to the present invention may be used in rubber industry in radial tyre production.