Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-05-03
2001-06-26
Davis, Robert (Department: 1722)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S909000, C157S013000, C425S017000, C425S019000
Reexamination Certificate
active
06251204
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to a machine for retreading tires; the invention concerns, in particular, a buffer as well as a combined machine further containing means for application and rolling down of the treads.
It is known that most tires can be retreaded, that is, it is possible—after normal wear of the tread —to replace that tread and even some of the plies reinforcing the belt of the tire. Such operations are very common for truck tires; they can be carried out in factories or at relatively large shops.
Numerous machines designed to remove remains of the tread from worn tires, a “detreading” operation, have been proposed. Among them, many use a buffer to carry out that detreading.
Such a buffer consists of a series of blades containing cutting teeth on the outside and arranged side by side. Such a machine is disclosed in U.S. Pat. No. 4,116,256. Those machines often contain complex adjustments for enabling the whole variety of necessary buffing profiles to be obtained.
More or less complex machines making it possible to reduce the different detreading or buffing and retreading operations, without resorting to overly frequent adjustments or repairs, have also been imagined. For example, U.S. Pat. No. 4,036,677 and French Patent 2,271,037, based on an Italian priority of May 14, 1974, describe an “all-purpose” machine comprising a rotary chuck on which the tire to be detreaded-retreaded is mounted, carcass buffing tools, a coaxial radial expander with the chuck, which brings the new tread around the carcass in the form of a ring, and means for rolling down in order to make the new tread adhere to the carcass.
The tire treated remains on the same chuck during buffing and molding, that is, application of the new tread, but without any interaction of the different parts of the machine, which results in a redundancy of drive units, and the need to mark several times the respective positions of the carcass and of the tread of the tire in the course of the successive operations.
The new tread can also be cut to the desired length and placed continuously on the carcass and then butted, that is, its two ends, once joined, are welded; a machine of that type is described in patent EP 0,704,296, but that machines carries out only the application of the new tread on the tire, the so-called “molding” operation.
SUMMARY OF THE INVENTION
According to the invention, a machine for retreading tires comprises a rotary chuck on which the tire to be treated is mounted and buffing tools. The machine is characterized in that the chuck is mounted on a first carriage guided in rails and moved by a first motor, in that the buffing tools are borne by a second carriage guided in rails oriented parallel to the axis of rotation of said chuck and moved by a second motor, in that means are provided for precisely positioning the first carriage relative to the second carriage and in that any relative displacement between the axis of rotation of the chuck and the center of the buffing tools is contained in a single plane passing through the axis of rotation of said chuck.
Such a machine makes it possible, by the combination of two simple translational movements, to obtain buffing profiles of the surface of the crown of a tire. The fact that any relative displacement between the axis of rotation of the chuck and the center of the buffing tools is contained in a single plane passing through the axis of rotation of the chuck has the advantage of remarkably simplifying the interpretation of each displacement, since any moving closer, by five millimeters, for example, will correspond to a reduction of radius of the tire precisely equal to five millimeters. Any relative displacement can thus be directly linked to a thickness of rubber to be removed.
According to one preferred embodiment, the first carriage is guided in vertical rails and the second carriage is guided in horizontal rails. The buffing tools are also preferably placed above the tire. This arrangement makes possible a saving of floor space.
According to an additional characteristic, the machine of the invention contains means for reversing the direction of rotation of the buffing tools. It can also embody additional means for setting parameters for the number of tires treated after which the direction of rotation of the buffing tools is reversed.
This characteristic has the advantage of optimizing wear of the buffing tools and of simplifying use of the machine. In fact, it is well known that the blades of a buffer wear irregularly on operation. Consequently, on the known machines, after having detreaded a given number of tires, in the order of 15 to 20, the blades of the buffer are usually removed, they are turned 180° (and they are remounted. This operation is particularly tedious. The machine according to the invention makes it possible to accomplish this by a simple reversal of the direction of rotation of the buffer, for example, after every three to ten tires have been treated, and the reversal can be accomplished automatically.
In case the machine according to the invention has to treat only tires recapped with flat treads, the axis of rotation of the buffer can be arranged parallel to the axis of rotation of the chuck. In that case, it is advantageous to reverse the direction of rotation of the machine automatically at the same time as the direction of rotation of the buffer is reversed. Of course, the direction of rotation of the tire and that of the buffer are identical in order to obtain a tangential speed on the surface of maximum contact.
When said machine must also detread tires which are to receive treads having tapered wings, usually called “bandes a bavettes,” these wings having to cover the shoulders and the height of the sides of the tires, it is advantageous to have the direction of rotation of the buffer perpendicular to the axis of rotation of the chuck.
This arrangement has the advantage of making it possible to treat all parts of the crown and shoulders of the tires by simple combination of both vertical movement of the chuck and horizontal movement of the buffing tools in very simple fashion. In that case, it is not necessary to reverse the direction of rotation of the chuck of the tire when the direction of rotation of the buffing tools is reversed.
The invention also concerns a similar machine further equipped with means for application of a tread and means for rolling down said tread after its application. Said means for application and said means for rolling down are carried by the second carriage and can be the same means.
The machine also makes it possible to combine all the means necessary for detreading and molding of a worn tire with a very low space requirement. Use of the same carriage for moving the buffing tools as well as the means of application and rolling down of the new tread also makes it possible to use the same markings for all the retreading operations; it is not necessary to use additional means of measurement.
The machine preferably also contains means for separating the position of the application and rolling down means from the movement of said second carriage. This makes it possible, notably, to place the buffing tools axially away from the tire during the molding operations. This is very important in order to guarantee that there will be no contamination of the surface of the tire, for example, during the usual operations of rubber coating, placement of the bonding rubber or application of the new tread. Such contamination by particles coming off the blades of the buffer would be unacceptable.
The invention further concerns a machine for retreading tires comprising a rotary chuck on which the tire to be treated is mounted, means of application of a tread and means of rolling down said tread after its application, characterized in that the chuck is mounted on a first carriage guided in vertical rails and moved by a first motor, in that the means of application of a tread and the means of rolling down said tread after its applications are borne by a second carriage guided in
Andersson Thomas
Reppel Emil Willi
Baker & Botts L.L.P.
Davis Robert
Del Sole Joseph S
Recamic S.A.
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