Bending of sheets of glass running on a bed of rolls
A device for bending sheets of glass running between a bed of upper rolls and a bed of lower rolls forming a shaping bed that pinches the sheets as they run, the shaping bed being disposed in a path having a curved profile in the running direction of the sheets of glass, the shaping bed including at least one roll of what is known as the rod/sheath type including a fixed metal rod preformed in a curved profile lengthwise and a flexible sheath that is able to rotate about the rod, the sheath being rotated about the rod. The roll of the rod/sheath type may include a metal rod preformed in a curved profile lengthwise and a flexible sheath that is able to rotate about the rod, the sheath including a first envelope made of a polymer material and a second envelope made of a flexible metal material disposed around the first envelope, the first and the second envelope rotating together as one.
1. A device for bending sheets of glass running between a bed of upper rolls and a bed of lower rolls forming a shaping bed that pinches the sheets of glass as the sheets of glass run, said device comprising said shaping bed that is disposed in a path having a curved profile in a running direction of the sheets of glass, a rotating assembly and a clamp,
wherein said shaping bed comprises at least one roll, said roll comprising a metal rod preformed in a curved profile lengthwise and a flexible sheath that is able to rotate about the rod, said sheath comprising a first envelope made of a polymer material and a second envelope made of a flexible metal material disposed around the first envelope so that the sheath is sufficiently deformable to follow the curved profile of the preformed metal rod, the first and the second envelope arranged to rotate together as one,
wherein said clamp is arranged to clamp the flexible sheath to the rotating assembly only by way of the second envelope so that rotation of the flexible sheath by the rotation assembly is carried out only by way of the second envelope and rotation of the second envelope by the rotating assembly rotates the first envelope.
2. The device as claimed in claim 1 , wherein the flexible metal material is made of woven or braided fibers.
3. The device as claimed in claim 1 , wherein the polymer material is made of PTFE or polyethylene.
4. The device as claimed in claim 1 , wherein the second envelope is covered by a sock of fibers.
5. The device as claimed in claim 1 , comprising a lubricant between the preformed metal rod and the first envelope.
6. The device as claimed in claim 1 , wherein the flexible sheath is rotated by one side of the roll and the metal rod is kept fixed by another side of the roll.
7. The device as claimed in claim 1 , wherein the shaping bed comprises at least one pair of said rolls placed on either side of the running sheets of glass in order to pinch them together.
8. The device as claimed in claim 1 , comprising three juxtaposed pairs of said rolls, the axes of the three upper rolls of the three juxtaposed pairs not being aligned, and the axes of the three lower rolls of the three juxtaposed pairs not being aligned, such that the sheets of glass are deformed as the sheets of glass pass between the three juxtaposed pairs of rolls.
9. A method for bending sheets of glass by the device of claim 1 .
10. The device as claimed in claim 1 , wherein said second envelope is detached from the first envelope along a portion thereof and wherein said clamp is configured to clamp said portion to the rotating assembly.
11. The device as claimed in claim 1 , further comprising a first mandrel provided at a first end of the rod, wherein the mandrel is provided with securing elements that prevent the rod from rotating.
12. The device as claimed in claim 11 , wherein the rotating assembly comprises a second mandrel that is rotatable about the rod by way of a ball bearing.