Chain tensioning device for bindery lines

A bindery gathering chain and conveyor apparatus, timed to signature delivery stations, comprising:

• first and second idling sprockets mounted in fixed relation to one another to define first and second fixed reference points;
• an endless conveyor chain which rides on the first and second idling sprockets;
• a tensioning sprocket support located relative to the first and second fixed reference points;
• a tension sprocket attached to the tensioning sprocket support and having the endless conveyor chain riding on the tension sprocket;
• a pneumatic actuator using a first predetermined air pressure to move the tensioning sprocket support and the tension sprocket thereon and to apply a first force thereto for a high chain-tensioning mode of operation during rest, start or stop and a second low air pressure to move the tensioning sprocket support and to apply a second, lower force for the tension sprocket to provide a lower chain-tensioning mode of operation during other operating modes.

A bindery gathering chain and conveyor apparatus, timed to signature delivery stations, comprising:

• first and second idling sprockets mounted in fixed relation to one another to define first and second fixed reference points;
• an endless conveyor chain which rides on the first and second idling sprockets;
• a tensioning sprocket support located relative to the first and second fixed reference points;
• a tension sprocket attached to the tensioning sprocket support and having the endless conveyor chain riding on the tension sprocket;
• a pneumatic actuator moving the tensioning sprocket support and the tension sprocket to apply a first predetermined force thereto for a high chain-tensioning mode of operation during rest, start or stop and also to move the tensioning sprocket support and the tension sprocket to provide a second, lower predetermined force for a lower chain-tensioning mode of operation during other operating modes;
• and
• a fail safe tension stop positioned adjacent the tensioning sprocket support and cooperating therewith if the actuator should fail to stop movement of the tensioning sprocket support at a minimum tensioning position adjacent the low tensioning position.

A bindery gathering chain and conveyor apparatus, timed to signature delivery stations, comprising:

• first and second idling sprockets mounted in fixed relation to one another to define first and second fixed reference points;
• an endless conveyor chain which rides on the first and second idling sprockets;
• a tensioning sprocket support located relative to the first and second fixed reference points;
• a tension sprocket attached to the tensioning sprocket support and having the endless conveyor chain riding on the tension sprocket;
• a pneumatic actuator moving the tensioning sprocket support and the tension sprocket to apply a first predetermined force thereto for a high chain-tensioning mode of operation during rest, start or stop for a predetermined period and also to move the tensioning sprocket support and the tension sprocket to provide a second, predetermined lower force for a lower chain-tensioning mode of operation during other operating modes;
• a base for mounting the pneumatic actuator for sliding movement for shifting the actuator and to shift the location of the tension sprocket relative to the first and second idling sprockets to change the range of motion of the actuator when shifting between high and low forces being applied to the chain;
• and
• an electronic control system which recognizes start up and stop modes and switches the pneumatic actuator between the high chain-tensioning mode and the low chain-tensioning mode.