Method for producing pulling rods for use in manufacturing sheet glass

Abstract

Pulling rolls ( 13 ) for glass ribbons ( 11 ) and methods for manufacturing such rolls are provided. The rolls include a shaft ( 17 ), a plurality of heat-resistant discs ( 15 ) mounted on the shaft in face-to-face contact, and a pair of fittings ( 25 or 25,31 ) affixed to the shaft which apply an axial compressive force to the discs. The magnitude of the axial compressive force is adjusted so that the portions ( 27 ) of the roll surface ( 33 ) which contact the glass ribbon during use have a Shore D hardness at room temperature of between 30 and 55. The rolls achieve a long service life without applying excessive force to the glass ribbon or generating high levels of particulate contamination.

What is claimed is: 
     
       1. A method for producing a roll for pulling a glass ribbon comprising:
 (a) providing a shaft, two fittings, and a plurality of heat-resistant discs, said discs comprising refractory ceramic fibers, mica, and a heat resistant binder;   (b) assembling the plurality of heat-resistant discs on the shaft and compressing the discs between the fittings; and   (c) monitoring the amount of force used in step (b) to compress the discs and adjusting the number of discs if said force is outside a predetermined range;   wherein:
 (i) the roll has a roll surface, one or more portions of which are adapted to contact the glass ribbon during use of the roll; and 
 (ii) the predetermined range in step (c) is selected so that the one or more portions have a Shore D hardness at room temperature of between 30 and 55. 
   
     
     
       2. The method of  claim 1  wherein prior to step (a), the heat-resistant discs are pre-fired so that they exhibit substantially no compositional changes when exposed to the temperatures at which the roll pulls the glass ribbon. 
     
     
       3. The method of  claim 2  wherein the heat-resistant discs are pre-fired at a temperature of at least 700° C. for a period of at least two hours. 
     
     
       4. The method of  claim 2  wherein the heat-resistant discs prior to pre-firing comprise cellulose fibers. 
     
     
       5. The method of  claim 1  including the additional step of using the roll to pull a glass ribbon for at least 40 days. 
     
     
       6. A method of making glass sheets comprising:
 (A) forming a glass ribbon;   (B) applying tension to the glass ribbon using a pair of pulling rolls; and   (C) forming glass sheets from the glass ribbon;   
       wherein
 (I) each pulling roll comprises a shaft and a plurality of heat-resistant discs mounted on the shaft in face-to-face contact and compressed against one another, and 
 (II) each pulling roll has a roll surface which has one or more glass-engaging portions which contact the glass ribbon, wherein:
   (a) the discs, and thus each of the one or more glass-engaging portions, comprise refractory ceramic fibers, mica, and a heat resistant binder, and   (b) at room temperature, each of the one or more glass-engaging portions has a Shore D hardness of between 30 and 55.   
 
 
     
     
       7. The method of claim 6 wherein each of the one or more glass-engaging portions has a Shore D hardness at room temperature of between 40 and 55. 
     
     
       8. The method of claim 6 wherein in the absence of externally caused damage, each pulling roll is used to perform step (B) for at least 40 days. 
     
     
       9. The method of claim 6 wherein in the absence of externally caused damage, each pulling roll is used to perform step (B) for at least 75 days. 
     
     
       10. The method of claim 6 wherein in the absence of externally caused damage, each pulling roll is used to perform step (B) for at least 100 days. 
     
     
       11. The method of claim 6 wherein before being mounted on the shaft, the discs are fired so that they exhibit substantially no compositional changes when the pulling rolls are used in step (B). 
     
     
       12. The method of claim 11 wherein the discs are fired at a temperature of at least 700° C. for a period of at least two hours.