Tire assembly drum

• US 6,234,227 B1
• Filed: 12/10/1998
• Issued: 05/22/2001
• Est. Priority Date: 06/11/1996
• Status: Expired due to Term

• Current Assignee: Compagnie Generale Des Etablissements Michelin
• Original Assignee: Compagnie Generale Des Etablissements Michelin
• Inventors: Bosseaux, Bernard
• Primary Examiner(s): Knable, Geoffrey L.
• Application Number:
  US09/209,661
• Time in Patent Office: 894 Days
• Field of Search: 156/131, 156/135, 156/398, 156/415, 156/111, 156/132, 156/414, 156/416-420
• US Class Current: 156/398
• CPC Class Codes: B29D 2030/3214 Locking the beads on the drum; details of the drum in the bead locking areas, e.g. drum shoulders
• CPC Class Codes: B29D 30/246 Drums for the multiple stage building process, i.e. the building-up of the cylindrical carcass is realised on one drum and the toroidal expansion is realised after transferring on another drum expansion to a toroidal shape B29D30/36
• CPC Class Codes: B29D 30/36 Expansion of tyres in a flat form , i.e. expansion to a toroidal shape independently of their building-up process, e.g. of tyres built by the flat-tyres method or by jointly covering two bead-rings

Abstract

A shaping drum for a tire having two bead holding systems mounted facing one another on a central shaft. Each of the bead holding systems includes a support mounted to be movable axially relative to the shaft. On each support there is mounted an assembly which includes a plurality of rigid segments and an elastic membrane which surrounds them. The rigid segments are each mounted on the support and swing about an articulation, the axis of which is perpendicular to a radial plane. A seat is formed on each assembly, the seat being arranged axially on the inside of the articulations, the articulations forming a crown on the support. The elastic membrane is fixed to the support axially on the inside and on the outside of the crown of articulations.

Claims

1. A shaping drum for accommodating bead rotation in the manufacture of a tire on the drum, the drum including two bead holding systems mounted opposite each other on a central shaft, each bead holding system comprising:

a support movable axially relative to the shaft,

a plurality of rigid segments distributed in a circular array around the shaft, an articulation for mounting an axially outer end of each segment on the support for swinging motion of an axially inner end about the articulation from a retracted position to a bead clamping position, an elastic membrane at least partially covering the rigid segments, a bead seat formed in the segments axially inside the articulations, an axially outer fastening and an axially inner fastening fixing the membrane on the support, the membrane defining a stretchable span between the two fastenings which stretchable span extends above the bead seats and around the swinging inner ends of the segments, the distance of the span of the membrane from the axially outer fastening to the axially inner swinging ends of the segments in retracted positions being greater than three times the width of the bead seat and the span of the membrane between the axially inner fastening and the inner ends of the segments in retracted positions being greater than the width of the bead seat,

the said drum further comprising means for introducing a pressurizing fluid into the space about the central shaft for shaping the tire.

2. A drum as set forth in claim 1 in which, in each of the bead holding systems, the elastic membrane is fixed on the support so that the stretchable span extends entirely across the segments.

3. A drum according to claim 1 in which the stretchable span of the membrane between the inner swinging ends of the segments and the axially inner fastening extends beneath the axially inner ends of the segments spanning the bead seats in the retracted positions of the segments.

4. A drum according to claim 1, in which the support comprises a slide forming a cam with at least one ramp inclined relative to the axis of the drum, said slide being axially movable relative to said segments and to said support, and including rollers integral with said segments and cooperating with said cam to cause the swinging of said rigid segments.

5. A drum according to claim 4, in which the axially inner fixing means for said membrane is integral with the slide.

6. A drum according to claim 5, in which the axially inner fixing means is located radially beneath the segments when they are in the restrained position.

7. A drum according to claim 1, in which each rigid segment comprises a recess on its axially inner end, and including a spring arranged around the recesses of all the segments, so as to cause the return of the segments to a restrained position, said spring forming a projection on each segment, said projection defining a seat.