Parallel work operations and automatic carcass feeding

In the two-stage process of building a passenger car tire the first stage is to make the carcass. Our PU 15 SB tire building machine is used for the second stage of production, namely for assembling the belt package - which consists of two steel cord belts, the jointless cap ply and the tread -and of combining it with the carcass to make up the green tire.

The principle of the PU 15 SB machine is based on separating and paralleling the work operations of assembling the belt package and building the tire. This results in high machine productivity combined with very short cycle times, in particular, as well as a high level of tire quality.

Principle of Operation

How the PU15 SB works is clearly illustrated in our diagram showing one complete work cycle (see drawing). The carcass loader positions the carcass on the shaping head. This is where the centering and preshaping operations take place. At the same time the belt transfer ring takes the belt assembly from belt drum 1 and positions it centrally and symmetrically in the middle above the carcass.
The carcass is then expanded into the belt assembly. After the stitching procedure, the belt transfer ring carries the tire to the take-off point. Parallel to this,two processes take place at the belt machine:

• The first and second belt plies are assembled via partial automatic control on belt drum1.
• The jointless cap ply is automatically placed on belt drum 2 which already holds the steel belts.

Winding the cap ply, applying the belt and tread "from below"

Assemblies

Belt Machine
The belt machine contains two swing shafts, staggered by 180°, that receive and actuate the belt drums.

Shaping Machine
The main component of the shaping machine is its revolving, axially adjustable shaft system that accommodates the expander head. Its internal, wear-free, threaded spindle enables the carcass bead spacing to beadjusted.

Thanks to the bead-encompassing design of the expander head, the carcass is seated extremely precisely. Pressure regulation during the shaping process ensures the high quality of the uncured tire.

Transport Device
The transport device comprises the belt transfer ring carriage and the rigid, box-design, conveyor system. This system links up the belt and shaping machines and guarantees - together with the foundation plate - the whole unit's uniformly high level of precision.

Lamp Positioning Unit and Central Projectors

This unit consists of a total of four lasers arranged at the conveyor above the belt drum and the shaping tool. One laser points precisely to the center of the tread on the belt drum and another to the center of the belt assembly on the shaping head, so as to enable the operator to make a visual quality check. The other two lasers are adjusted by motor to comply with current recipe requirements and mark the target position of the belt ply edges.

Stitching Unit
The static stitcher is equipped with three pairs of rollers (1 x cylindrical, 2 x conical) which are successively swiveled forward to stitch the belt assembly down onto the shaped carcass. The stitching down process depends to a large extent on the product concerned. This is why we supply special versions on request.

Carcass Loader
The expanding and stretching unit takes the carcass from the conveyor, which can hold a maximum of six carcasses at once, gets it properly aligned and passes it on to the carcass mounting device which positions the carcass on the shaping head in according with recipe specifications.

Belt Ply Servicer
The servicer is designed to be used with cassettes for the provision of the belt material. Belt conveyors take on the job of advancing the belt strips into cutting position and - once they have been cut to length accordingly - into delivery position.
The two belt plies are placed on the drum one after the other. Synchronization between drum rotation and conveyor speed is carried out via digital synchronizing.

Jointless Cap Ply Station
This station consists of the let-off unit, the accumulator, the winding head holder and the winding heads. The strip material is unwound continuously from two spools. Automatic application of the jointless cap ply is carried out,
recipe-controlled, on the top of the belt drum with two separately controlled winding heads.

Tread Servicer
Via adjustable axial and vertical carriages the servicer is brought in line with the drum center and drum diameter and moved into the right position for tread delivery.
The integrated guide strip guarantees that the tread is placed exactly in the center.

Control
Electric controls are designed in conformity with currently EN directives. Machine sequences are controlled by an industrial PC. The operator works at a central panel with clearly arranged functional elements and a monitor. The controls permit editing of more than 100 recipes, machine data and parameters as well as the display of operating and error messages as diagnostic aids.
The machine's safety system is provided for by special, hardware-based electric circuits.

It is possible to work in the following modes of operation:

• Semi-automatic mode
• Manual mode
• Setup and maintenance mode

Tools

Belt Drum
The 32-piece belt drums are infinitely adjustable in diameter ranges
520 – 670 mm, 565 – 715 mm, 600 – 750 mm and 650 – 800 mm.

Belt Transfer Ring
The 11-piece belt transfer ring is infinitely adjustable in diameter ranges
520 – 700 mm, 600 – 770 mm and 720 – 840 mm.

Expander Head
For each tire size to be manufactured (tire bead diameter in inches) we can also supply the right expander head as shaping tool.

TECHNICAL DATA             POWER DATA                 DRAWING