System for positioning glass sheets for forming

Abstract

A forming system ( 10 ) having particular utility for making outer and inner formed windshield glass sheets provides glass sheet positioning centrally on a forming face ( 34 ) of a forming mold ( 32 ) to form each glass sheet to a design shape regardless of any size difference between the glass sheets from one cycle to the next.

1 . A glass sheet forming system comprising:
 a conveyor for conveying a heated glass sheet in a horizontally plane of conveyance along a direction of conveyance;   a forming station to which the conveyor conveys the heated glass sheet;   the forming station having a forming mold including a downwardly facing curved forming face that is positioned above the plane of conveyance and has a forming portion for forming a glass sheet of a predetermined size;   a detection system for measuring the spacing along the direction of conveyance between downstream and upstream extremities of the conveyed glass sheet;   a controller that coordinates the conveyor and the detection system to convey the glass sheet to a central position below the forming portion of the mold; and   transfer apparatus for transferring the centrally positioned glass sheet from the conveyor to the forming mold for forming of the glass sheet against the forming face.   
   
   
       2 . A glass sheet forming system as in  claim 1  wherein the detection system includes a single detector that initially detects the downstream extremity of the conveyed glass sheet and subsequently detects the upstream extremity of the conveyed glass sheet to generate a control signal corresponding to the size of the glass sheet, and the controller processing the control signal in coordination with the conveyor detection system to convey the glass sheet to the central position for the transfer to the mold forming face without stopping the conveyance prior to the transfer. 
   
   
       3 . A glass sheet forming system as in  claim 1  wherein the transfer apparatus is selected from the group consisting of: a lifter including a continuous ring for lifting the glass sheet upwardly from the conveyor to the forming mold; a lifter including a segmented ring for lifting the glass sheet upwardly from the conveyor to the forming mold; a vacuum supply for drawing a vacuum at the curved forming face of the forming mold; a control for moving the forming mold downwardly toward the conveyor; a gas supply for blowing gas upwardly from below the glass sheet to lift the glass sheet upwardly from the conveyor; and any combination of two or more of the continuous ring lifter, the segmented ring lifter, the vacuum supply, the mold control and the gas supply. 
   
   
       4 . A glass sheet forming system as in  claim 1  which includes a lateral positioner that laterally positions the glass sheet on the conveyor at a central lateral position. 
   
   
       5 . A glass sheet forming station as in  claim 4  further including a furnace to which the glass sheet is conveyed after the lateral position for heating prior to the conveyance to the central position below the forming mold for the transfer to its forming face. 
   
   
       6 . A glass sheet forming system for forming larger outer glass sheets and smaller inner glass sheets in an alternate manner, the system comprising:
 a conveyor for conveying a heated glass sheet in a horizontally plane of conveyance along a direction of conveyance;   a loading station at which the outer glass sheets and the inner glass sheets are alternately loaded onto the conveyor;   a lateral positioner that initially laterally positions each glass sheet on the conveyor at a central lateral location;   a furnace to which the conveyor conveys the glass sheets for heating;   a forming station to which the conveyor conveys the heated glass sheet from the furnace;   the forming station having a forming mold including a downwardly facing curved forming face of a design shape that is positioned above the plane of conveyance and has a forming portion for forming a glass sheet of a predetermined size;   a detection system including a detector for initially detecting a downstream extremity of the conveyed glass sheet and for subsequently detecting an upstream extremity of the conveyed glass sheet to measure the spacing of the glass sheet along the direction of conveyance between its downstream and upstream extremities, and the subsequent detection by the detector of the upstream extremity of the conveyed glass sheet generating a control signal;   a controller that controls the conveyor in response to the control signal of the detection system to convey the glass sheet to a central position below the forming portion of the forming mold; and   transfer apparatus for transferring the centrally positioned glass sheet from the conveyor to the forming mold for forming of the glass sheet against the forming face, and the transfer apparatus being selected from the group consisting of: a lifter including a continuous ring for lifting the glass sheet upwardly from the conveyor to the forming mold; a lifter including a segmented ring for lifting the glass sheet upwardly from the conveyor to the forming mold; a vacuum supply for drawing a vacuum at the curved forming face of the forming mold; a control for moving the forming mold downwardly toward the conveyor; a gas supply for blowing gas upwardly from below the glass sheet to lift the glass sheet upwardly from the conveyor; and any combination of two or more of the continuous ring lifter, the segmented ring lifter, the vacuum supply, the forming mold control and the gas supply.