Process and drum for constructing a green tire

• US 20010000582A1
• Filed: 12/20/2000
• Published: 05/03/2001
• Est. Priority Date: 09/24/1997
• Status: Active Grant

• Current Assignee: Continental Reifen Deutschland GmbH (Continental AG)
• Original Assignee: Continental AG
• Inventors: Menell, Hans, Sergel, Horst
• Granted Patent: US 6,539,998 B2
• Time in Patent Office: Days
• US Class Current: 156/131
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29D 2030/2692 by using suction means, e.g. vacuum producing devices
• 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 30/26 Accessories or details, e.g. membranes, transfer rings

Abstract

Expandable drum for constructing a green carcass of a tire has a periphery and includes a plurality of metal segments positioned to form a substantially cylindrical arrangement, adapted for radial expansion and compression. A thick-walled casing, positioned over the plurality of metal segments, forms the drum periphery. The thick-walled casing includes rubber and a plurality of voids arranged to have an outer periphery in the thick-walled casing. An evacuating pump is coupled to the plurality of voids. The plurality of voids form suctioning voids to suction the green carcass onto the drum periphery during compression of the drum periphery, and are coupled at radially outermost extents to a network of grooves arranged to provide wave-free and smooth contraction of green carcass during its compression, thereby avoiding bulges and creases in contracting green carcass. Radially innermost extents of the voids are coupled to evacuating pump to create vacuum in the grooves.

Claims

1. An expandable drum for constructing a green carcass of a tire, the drum having a periphery and comprising:

a plurality of metal segments positioned to form a substantially cylindrical arrangement, which is adapted for radial expansion and compression;

a thick-walled casing comprising rubber, the thick-walled casing being positioned over the plurality of metal segments, thereby forming the drum periphery;

the thick-walled casing comprising a plurality of voids arranged radially inwardly into the thick-walled casing; and

an evacuating pump coupled to the plurality of voids, wherein the plurality of voids form suctioning voids adapted to suction the green carcass onto the drum periphery during compression of the drum periphery,

wherein the plurality of voids are coupled at their radially outermost extents to a network of grooves arranged to provide a wave-free and smooth contraction of the green carcass during its compression, thereby avoiding bulges and creases in a contracting green carcass, and

wherein radially innermost extents of the voids are coupled to the evacuating pump to create a vacuum in the grooves.

2. The drum in accordance with

claim 1

, the grooves have a width and a depth of approximately 3% of a drum diameter.

3. The drum in accordance with

claim 2

, the grooves being arranged substantially axially along the drum periphery.

4. The drum in accordance with

claim 3

, further comprising a peripherally arranged groove positioned at each end of the drum periphery, the peripherally arranged groove being coupled to each of the substantially axially arranged grooves.

5. The drum in accordance with

claim 3

, the plurality of voids being arranged in two peripherally positioned rows;

and

each void is coupled to an adjacent void in the peripheral direction.

6. The drum in accordance with

claim 5

, adjacent voids in different peripherally positioned rows are coupled by the substantially axially arranged grooves.

7. The drum in accordance with

claim 1

, the casing being mounted while the metal segments are contracted to a diameter D0 whereby the sum D1 of the diameter D0 plus twice the thickness of the casing is smaller than the smallest diameter D2 being used during the process and during conveyance and preferably also positioning bead cores and preferably during pulling off the produced carcass, so that the casing has during the entire process an internal tensile stress in the circumferential direction.

8. The drum in accordance with

claim 1

, wherein the plurality of voids comprise substantially circular voids.

9. The drum in accordance with

claim 1

, wherein the interior of each void includes a connecting hole coupled to the evacuating pump via a tube line.

10. The drum in accordance with

claim 9

, wherein each connecting hole is located in a bottom surface of the each of the plurality of voids.

11. The drum in accordance with

claim 1

, wherein the plurality of suctioning voids are located on an outer surface of the thick-walled casing and one of on the inner surface of the thick-walled casing and one the outer surface of the metal segments.

12. An expandable drum for constructing a green tire comprising:

a plurality of metal segments arranged to form a substantially cylindrical arrangement, which is adapted for radial expansion and compression;

a casing slidably positionable over said plurality of metal segments, thereby forming a drum periphery, wherein said plurality of metal segments are radially expandable so that a diameter of said drum periphery corresponds to an inside diameter of a carcass sleeve;

a plurality of voids formed in said drum periphery;

an evacuating pump coupled to said plurality of voids in order to suction the carcass sleeve onto said drum periphery during a radial compression of said plurality of metal segments, whereby substantially even radial compression of the carcass sleeve occurs.

13. The expandable drum in accordance with

claim 12

, further comprising a plurality of grooves formed in said drum periphery, which are arranged to coupled said plurality of voids to each other and to provide additional suction on the carcass sleeve to said drum periphery, whereby bulges and creases in the green tire during radial compression is avoided.

14. An expandable drum for constructing a green carcass of a tire, the drum having a periphery and comprising:

a plurality of metal segments positioned to form a substantially cylindrical arrangement, which is adapted for radial expansion and compression;

a thick-walled casing comprising rubber, the thick-walled casing being positioned over the plurality of metal segments, thereby forming the drum periphery;

the thick-walled casing comprising a plurality of voids arranged to have an outer periphery in the thick-walled casing; and

an evacuating pump coupled to the plurality of voids, wherein the plurality of voids form suctioning voids adapted to suction the green carcass onto the drum periphery duting compression of the drum periphery,

wherein the plurality of voids are coupled at their outer peripheries to a network of grooves arranged to provide a wave-free and smooth contraction of the green carcass during its compression, thereby avoiding bulges and creases in a contracting green carcass, and

wherein an interior of the voids are coupled to the evacuating pump to create a vacuum in the grooves.