Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-04-26
2003-10-14
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S117000, C156S130000, C156S397000
Reexamination Certificate
active
06632307
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a tread band applicator device operable to apply a tread band raw material mass onto a carcass of a tire to form thereon a tread band and, in particular, to form a tread band on the carcass of a tire having an especially long performance life.
A conventional tread band applicator device is described in FR-OS 23 59 700. This conventional tread band applicator device comprises a forming applicator which is connected to an extruder and is operable to apply a tread band raw material mass on the tire carcass. The application of the tread band raw material mass includes deposing a predetermined excess of the material mass onto the tire carcass, whereby a rubber roller is deployed to effect the filling of inadequately filled locations on the tire carcass.
A disadvantage of the just noted conventional tread band applicator device is that a special forming applicator configured with respect to the diameter of the tire to be handled must be used so that an inventory of different forming applicators for handling tires of differing diameters must be kept on hand.
The conventional tread band applicator device described in the above-noted publication may, however, fail to reliably completely fill the relatively deeper recesses in the tire carcass so that it is necessary, prior to the tread band applying process, to perform a labor intensive preparation of the tire with a small hand extruder in order to foreclose the possibility that air pockets and inadequately filled locations will remain in the tire to such an extent that the quality requirements of the tire retreader and its customers would not be met.
Additionally, the afore-described tread band applicator device is effective in its operation only within the range of applications in which the carcass diameter does not deviate substantially from a given diameter; otherwise, the tread bands applied in an application outside of this range will be markedly thick and/or markedly thin, either of which leads to unsatisfactory results upon vulcanization of the tire.
In order that the afore-described tread band applicator device can perform in a relatively satisfactory manner, it is additionally necessary that a relatively soft rubber mixture is used to form the tread band raw material mass. In such relatively soft rubber mixtures, the portion of solid particles is reduced; the traction of the retreaded tire formed therefrom is for the most part very good while, on the other hand, the performance life of the tire is decidedly short.
It must be noted, however, that, in view of the rising quality demands of customers, tires with a high performance life are increasingly in demand. The incorporation of solid particles of various types into the rubber mixture, as well as adjustment of the rubber mixture, permits not only that the traction of the tire and its performance life be adjusted, but also permits adjustment of the accumulated drum work and the degree of heat build up in the tire during use. Thus, tires have been proposed for commercial vehicles and trucks whose performance life extends to over 800,000 kilometers, whereby correspondingly relatively hard and wear resistant tread bands are required.
A further disadvantage of conventional tread band applicator devices is that the impact of the tread strips must be renewed with higher precision. Careful follow up labor is required to achieve a relatively acceptable result. Moreover, an undesirable value of the so-called mold filling factor comes into play which leads to a correspondingly greater generation of scraps. This disadvantage should be overcome by the so-called camelback process in which a pre-prepared tread band is applied onto the tire carcass. To be sure, grinding holes occur in connection with this process which then must be filled in a labor intensive operation.
The tread band applicator device described in FR-OS 23 59 700 would not be suitable for producing those tires upon which the high quality demands noted herein are placed.
Numerous other tread band applicator devices have been proposed. EP-A1 637 506 makes note of several patent publications which set forth the state of the art of such tread band applicator devices. A tire retreading device, which operates relatively independently of the given diameter of the tire being handled, is described in DE 42 03 027 and the width of the tread band applied by this device can be adjusted to accommodate the retreading requirements.
It has been known for several years, moreover, to apply tread bands by winding them onto the tire carcass in spiral strips. This manner of applying tread bands was implemented in the 1970s, whereby, for example, DE-PS 17 29 555 describes one such exemplary application of this type. This tread band applying approach is today, however, only infrequently implemented as it cannot be ensured by this approach that air has not been trapped in the applied tread bands. At the same time, the geometry of the tread bands is relatively inexact and the production of a tread band can require up to 5 minutes.
SUMMARY OF THE INVENTION
The present invention offers a solution to the challenge of providing a tread band applicator device which is advantageous as well for applying tread bands to tires of large diameter, even if a high performance life of the tire is demanded.
In accordance with the present invention, it is particularly advantageous that the configuration of the press applicator head of the tread band applicator device of the present invention, which moves transversely over the tire carcass to apply the tread band raw material mass, permits the advantages of the known tread band applicator devices to be combined: the press applicator head, which is preferably configured as the extruder itself or as a component of the extruder, can be moved transversely across the outer surface of the tire carcass in such a manner that the tread band strips are circumferentially applied to the tire carcass in thin bands during rotation of the tire carcass. In this manner, the already applied tread band strips act as support for the newly applied tread band strips. In view of the fact that the tread band rubber mixture is relatively hard, a good driving out or expulsion of air results. It is particularly advantageous in connection with this process that the extrusion front, which is formed by the simultaneous pressure and extrusion movement of the tread band raw material mass which has just exited the extruder structure, effectively pushes away the air so that the risk of included or trapped air is foreclosed.
It is particularly advantageous if a side flank of the extruder is formed with a ball or curved shape and if this side flank of the extruder initially leans against the carcass and then, after the beginning of the application of the tread band, leans against the already applied tread band. The thickness of the tread band strips allows for very responsive and precise control of their application by these techniques, whereby, at the same time, it is possible to compensate for any out of roundness areas.
The extrusion of the tread band raw material mass is preferably performed in a manner such that a deliberate over extrusion of the tread band raw material mass is provided which is wrapped around the carcass due to the rotation of the carcass and which is beneficial for a uniform loading of the carcass with the tread band raw material mass.
In accordance with the present invention, it is particularly advantageous if the extruder is pivotable relative to four axes and, in particular, is pivotable relative to five axes. In this manner, it is possible to control the extruder to follow the desired contour of the tire without necessitating an additional capability to adjust the carcass mounting during the tread band applying process.
In accordance with a modified embodiment of the tread band applicator device of the present invention, it is provided that the extruder is configured with a special extruder outlet piece which serves as the press applicator head and is pivotable r
A-Z Formen- und Maschinenbau GmbH
Becker R W
Knable Geoffrey L.
R W Becker & Associates
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