Method of taking up wear of a grinding wheel on a machine for grinding sheets of glass, and grinding machine implementing such a method

Abstract

A method of taking up wear of a grinding wheel on a machine for grinding sheets of glass, whereby the position of an abrasive surface of the grinding wheel, initially set to an ideal work position such as to obtain a sheet of a given size, is adjusted, following wear of the grinding wheel, by moving the abrasive surface towards a reference surface on the machine, positioned facing and at a predetermined distance from the abrasive surface when the abrasive surface is in the ideal work position; determining the instant of contact between the abrasive surface and the reference surface; arresting the grinding wheel at the instant of contact; and moving the abrasive surface away from the reference surface to an adjustment distance at least equal to the predetermined distance.

1 ) A method of taking up wear of a grinding wheel ( 7 ) on a machine ( 1 ) for grinding sheets ( 2 ) of glass; the method comprising the steps of setting an abrasive surface ( 12 ) of the grinding wheel to an ideal work position, such as to obtain a sheet of desired characteristics; and adjusting the position of the grinding wheel ( 7 ) to restore said abrasive surface ( 12 ) to said ideal work position following wear of the grinding wheel ( 7 ); characterized in that adjustment of the position of the grinding wheel ( 7 ) comprises the steps of moving said abrasive surface ( 12 ) towards reference means ( 31 ) on said machine ( 1 ), positioned facing and a predetermined distance (A) from said abrasive surface ( 12 ) when the abrasive surface ( 12 ) is in said ideal work position; determining the instant of interference between said abrasive surface ( 12 ) and said reference means ( 31 ); arresting said grinding wheel ( 7 ) at said instant of interference; and moving said abrasive surface ( 12 ) away from said reference means ( 31 ) to an adjustment distance at least equal to said predetermined distance (A).  
     
     
         2 ) A method as claimed in  claim 1 , characterized in that said adjustment distance is greater than said predetermined distance (A); and by comprising the further step of moving said abrasive surface ( 12 ) towards said reference means ( 31 ) by a quantity equal to the difference between said adjustment distance and said predetermined distance (A).  
     
     
         3 ) A method as claimed in  claim 1 , characterized in that the instant of interference is determined by detecting a shift-start condition of said reference means ( 31 ) with respect to a frame ( 5 ) of the machine ( 1 ).  
     
     
         4 ) A method as claimed in  claim 3 , characterized in that the instant of interference is determined by elastically locking said reference means ( 31 ) with respect to the frame ( 5 ) of the machine ( 1 ).  
     
     
         5 ) A method as claimed in  claim 3 , characterized in that the shift-start condition of said reference means ( 31 ) is detected by detecting a variation in a shift signal.  
     
     
         6 ) A method as claimed in  claim 5 , characterized in that the shift-start condition of said reference means ( 31 ) is detected by detecting a variation in an electric signal emitted by an electric detector ( 47 ) connected to said reference means ( 31 ).  
     
     
         7 ) A machine ( 1 ) for working sheets ( 2 ) of glass, comprising a supporting frame ( 5 ); a grinding wheel ( 7 ) defined by an abrasive surface ( 12 ); actuating means ( 16 ,  17 ) for setting and maintaining said abrasive surface ( 12 ) in an ideal work position such as to obtain a sheet of desired characteristics; and adjusting means ( 20 ) for adjusting the position of the grinding wheel ( 7 ) with respect to said supporting frame ( 5 ), and restoring said abrasive surface ( 12 ) to said ideal work position following wear of the grinding wheel ( 7 ); characterized in that said adjusting means ( 20 ) comprise reference means ( 31 ) fitted to said supporting frame ( 5 ) and facing and a predetermined distance (A) from said abrasive surface ( 12 ) when the abrasive surface ( 12 ) is in said ideal work position; first actuating means ( 16 ,  17 ,  18 ) for moving said abrasive surface ( 12 ) towards said reference means ( 31 ); detecting means ( 21 ) for determining the instant of interference between said abrasive surface ( 12 ) and said reference means ( 31 ); stop means ( 16 ,  17 ,  18 ) for arresting said grinding wheel at the instant of interference; and second actuating means ( 16 ,  17 ,  18 ) for moving said abrasive surface ( 12 ) away from said reference means ( 31 ) and to an adjustment distance at least equal to said predetermined distance (A).  
     
     
         8 ) A machine as claimed in  claim 7 , characterized in that said first and said second actuating means comprise a single drive motor ( 16 ), and a respective slide ( 13 ) supporting said grinding wheel ( 7 ).  
     
     
         9 ) A machine as claimed in  claim 7 , characterized in that said reference means comprise a reference surface ( 31 ).  
     
     
         10 ) A machine as claimed in  claim 9 , characterized in that said reference surface ( 31 ) is parallel to said abrasive surface ( 12 ).  
     
     
         11 ) A machine as claimed in  claim 7 , characterized in that said reference means ( 31 ) comprise a reference line.  
     
     
         12 ) A machine as claimed in  claim 7 , characterized by comprising relatively movable means ( 23 ,  25 ,  39 ) interposed between said supporting frame ( 5 ) and said reference means ( 31 ); and in that said detecting means ( 21 ) comprise sensor means ( 47 ) for detecting movement of said reference means ( 31 ) with respect to said supporting frame ( 5 ).  
     
     
         13 ) A machine as claimed in  claim 12 , characterized in that said sensor means comprises an electric switch ( 47 ); connecting means ( 25 ,  49 ) being provided to connect said electric switch ( 47 ) to said reference means ( 31 ).  
     
     
         14 ) A machine as claimed in  claim 13 , characterized by comprising elastic forcing means ( 39 ) for locking said reference means ( 31 ) elastically with respect to said supporting frame ( 5 ).  
     
     
         15 ) A machine as claimed in  claim 14 , characterized in that said relatively movable means and said connecting means comprise a rod ( 25 ) fitted to said supporting frame ( 5 ) to slide in a longitudinal direction ( 15 ); said elastic means ( 39 ) forcing said rod ( 25 ) against a stop ( 42 ) carried by said supporting frame ( 5 ).  
     
     
         16 ) A machine as claimed in  claim 15 , characterized in that said rod ( 25 ) extends to the side of said grinding wheel ( 7 ); said reference means ( 31 ) projecting from an end portion of said rod ( 25 ); and said sensor means( 47 ) extending on the opposite side of said grinding wheel ( 7 ) to said reference means ( 31 ), and at a distance from the grinding wheel ( 7 ).  
     
     
         17 ) A machine as claimed in  claim 16 , characterized by comprising adjusting means ( 25 ,  42 ) for adjusting the position of said reference means ( 31 ) with respect to said supporting frame ( 5 ).