Conveyor drive system for a glass sheet manufacturing system

In a conveyor drive system for transporting a sheet glass load through a glass processing station along a direction of travel of the type having:

• a conveyor drive defined by at least one continuous drive loop trained over first and second pulleys mounted at opposite ends of a lateral side of the processing station;
• a plurality of elongated rollers spaced apart from one another along the direction of travel and extending transversely with respect thereto, the plurality of rollers being in driving engagement with the conveyor drive for rotational motion upon motion of the continuous drive loop;
• first torque means, coupled to the first pulley of the conveyor drive and responsive to a first control signal, for applying a drive torque to the first pulley in accordance with the first control signal;
• first and second electrical drive motors associated with the second pulley of the conveyor drive and responsive to first and second electrical control signals, for applying a resultant counter-drive torque to the second pulley;
• feedback means associated with the first torque means for producing a feedback signal representative of the rotational speed of the first pulley;
• an improved control circuit, wherein said control circuit is responsive to a transport speed command signal and the feedback signal, for providing the first control signal to drive the first pulley in accordance with the transport speed command, said control circuit including first and second electrical channel circuits for providing the first and second electrical control signals, respectively, and first and second electrical feedback circuits coupled, respectively, to the first and second electrical drive motors and the first and second electrical channel circuits for providing first and second electrical feedback signals related to an electrical characteristic of the first and second electrical drive motors, respectively, wherein said first and second electrical channel circuits are responsive to said first and second electrical feedback signal for the purpose of stabilizing the motion of the conveyor drive.