Tilting roller system for folding a pneumatic tire carcass insert around a bead core and folding-up method

1 . A folding-up system intended to fold an end section of a cylindrical wall of a tire carcass assembly around a reinforcing bead core of said carcass assembly, said cylindrical wall extending along and around a central roll axis, and said reinforcing bead core extending along a generatrix forming a ring around said roll axis, said system comprising:

a folding device, comprising at least one pressing member such as a pressure roller, and arranged to cause said pressing member to be applied against a radially outer face of the end section, in an angular working sector of the cylindrical wall which corresponds to a fraction of a circumference of the end section around the roll axis, and to cause said pressing member to execute a tilting pitching movement about the generatrix of the reinforcing bead core, so that the pressing member folds the portion of the end section located in the angular working sector concerned towards a radially inner face of the cylindrical wall of the carcass assembly, around the reinforcing bead core,

a drive device designed to modify a relative position of the pressing member, by successive angular increments, with respect to the carcass assembly about the roll axis, so that the pressing member can execute its tilting pitching movement in different angular working sectors in order to fold the corresponding portions of the end section one after another,

a selector designed to place the pressing member, alternately, in a working configuration, enabling said pressing member to bear against the radially outer face of the end portion in the angular working sector concerned and to force the corresponding portion of the end section to be folded when the folding device executes the tilting pitching movement in said angular working sector concerned, and then in a withdrawn configuration which prevents said pressing member from interfering with the end section when the drive device modifies the relative position of said pressing member with respect to the cylindrical wall of the carcass assembly, about the roll axis, to change the angular working sector,

wherein the system comprises an automatic sequencer that is programmed to execute and repeat, as often as required, until the end section has been pressed, along its whole circumference about the roll axis, against the radially inner face of the wall of the carcass assembly, during an elementary sequence:

the selector places at least one pressing member in the working configuration;

the folding device causes said at least one pressing member to execute the tilting pitching movement about the generatrix of the reinforcing bead core, in the angular working sector in question, so as to fold towards the radially inner face of the wall of the carcass assembly the portion of the end section that is located in said angular working sector;

the selector places the at least one pressing member back in the withdrawn configuration;

the drive device offsets the wall of the carcass assembly about the roll axis by a chosen angular increment, relative to the at least one pressing member, so as to place said at least one pressing member in a new angular working sector, separate from the preceding angular working sector in question.

2 . The system according to claim 1 , wherein the folding device comprises a plurality of pressing members which are offset angularly from one another in azimuth about the roll axis, so as to engage with the radially outer face of the end section in different angular working sectors placed in succession around the roll axis, along the generatrix of the reinforcing bead core, and wherein said plurality of pressing members have ranges of pitch travel about the generatrix that are complementary to one another, so that each pressing member intensifies in turn, by an individual contribution, the folding of the end section over and around the reinforcing bead core towards the radially inner face of the wall of the carcass assembly.

3 . The system according to claim 2 , wherein each of the plurality of pressing members provides, in its tilting pitching movement, the individual contribution to the folding of the end section, which individual contribution corresponds to an amplitude of angular movement of the pressing member in question, in pitching about the generatrix of the reinforcing bead core, which is at least equal to 30 degrees for the each pressing member in question.

4 . The system as set forth in claim 3 , wherein the amplitude of the angular movement of the pressing member is in the range of 60 degrees to 120 degrees.

5 . The system according to claim 1 , wherein the drive device comprises a receiving support which is mounted on a frame and which is arranged to receive the carcass assembly and to drive said carcass assembly in rotation relative to the frame, by successive angular increments, about the roll axis, and in that the folding device comprises a tilting base carrying an arm supporting the pressing member, which tilting base is mounted for rotation relative to the frame about a pitch axis, which is transverse and orthogonal to the roll axis, and which embodies the axis about which the tilting pitching movements of the pressing member.

6 . The system according to claim 5 , wherein the arm carrying the pressing member has a degree of freedom in differential pitch rotation relative to the tilting base, this differential pitch rotation taking place about the pitch axis or about an axis parallel to said pitch axis and separate from said pitch axis, and being dependent on an elastic member.

7 . The system according to claim 5 , further comprising a plurality of pressing members, and wherein the plurality of pressing members are carried by the same tilting base, so that the rotation of said tilting base drives said plurality of pressing members jointly in their tilting pitching movement about the reinforcing bead core.

8 . The system according to claim 1 , wherein the selector comprises a pneumatic actuator associated with the pressing member, or a plurality of pneumatic actuators, each associated with one of the plurality of pressing members, said pneumatic actuator being arranged, to control a passage of the pressing member associated therewith from the withdrawn configuration to the working configuration and vice versa, and to provide, in the working configuration, pre-stressing and elastic suspension of the pressing member in question against the end section.

9 . The system according to claim 1 , wherein the folding device is arranged so as to cause the pressing member to execute, in the angular working sector concerned, an outward and return tilting pitching movement about the generatrix of the reinforcing bead core, from a pitch starting position to a pitch arrival position, and then in reverse, from the pitch arrival position, to return to the pitch starting position.

10 . The system according to claim 1 , wherein the pressing member, and if appropriate each pressing member, is formed by a pressure roller which is mounted rotatably on its central axis, which central axis is, and remains during the tilting pitching movement, substantially parallel, at +/−10 degrees to the normal to a radial bisecting plane that contains the roll axis together with the bisector of the angular working sector where the tilting pitching movement of the pressure roller starts.

11 . The system as set forth in claim 1 , wherein the automatic sequencer is an electronic control unit.