Apparatus and method for enhancing heating uniformity for setting adhesive in corrugated paperboard manufacturing

An apparatus for setting an adhesive in corrugated paperboard during the manufacturing thereof, said apparatus comprising:

• heating means for defining a heating surface;
• a conveyor belt positioned opposite said heating surface for advancing a corrugated paperboard sheet longitudinally along a predetermined path of travel over said heating surface;
• and
• sliding contact means associated with a back side of said conveyor belt for slidably contacting and pressing upon the back side of said conveyor belt so as to urge the advancing corrugated paperboard sheet into substantially uniform contact with the heating surface, said sliding contact means comprising a plurality of contact assemblies, each contact assembly comprising
• a laterally extending frame positioned adjacent the back side of said conveyor belt,
• a plurality of contact shoes carried by said frame and arranged in side-by-side laterally extending relation, each of said contact shoes having a contact surface for slidably contacting the back side of said conveyor belt,
• respective springs operatively connected between said frame and each of said contact shoes for independently biasing the contact surface of each of said shoes against the back side of said conveyor belt,
• mounting means for mounting each of said contact shoes to said frame so that the contact surface of each of said shoes is independently moveable along a predetermined path of travel generally normal to said conveyor belt, and
• stop means operatively connected between said frame and each of said contact shoes for defining a predetermined minimum spacing between each of said contact surfaces and a respective portion of said heating surface so that backing pressure is provided for a corrugated paperboard sheet having a predetermined minimum thickness and to thereby relieve pressure on the back side of said conveyor belt when the apparatus is operated without the corrugated paperboard sheet in place adjacent a respective portion of said conveyor belt.

A contact assembly adapted to be positioned on an apparatus of the type for setting an adhesive in corrugated paperboard during the manufacturing thereof, the apparatus comprising heating means for defining a heating surface and a conveyor belt positioned opposite the heating surface for advancing a corrugated paperboard sheet along a predetermined path of travel over said heating surface, said contact assembly comprising:

• a frame adapted to be positioned adjacent the back side of the conveyor belt and extending laterally thereacross;
• a plurality of contact shoes carried by said frame and arranged in side-by-side laterally extending relation, each of said contact shoes having a contact surface adapted for slidably contacting the back side of said conveyor belt;
• biasing means operatively connected between said frame and each of said contact shoes and adapted for independently urging the contact surface of each of said shoes against the back side of the conveyor belt;
• mounting means for mounting each of said contact shoes to said frame so that the contact surface of each of said shoes is independently moveable along a predetermined path of travel generally normal to the conveyor belt, and
• stop means operatively connected between said frame and each of said contact shoes for defining a predetermined minimum spacing between each of said contact surfaces and a respective portion of said heating surface so that backing pressure is provided for a corrugated paperboard sheet having a predetermined minimum thickness and to thereby relieve pressure on the back side of said conveyor belt when the apparatus is operated without the corrugated paperboard sheet in place adjacent a respective portion of said conveyor belt.

A contact assembly adapted to be positioned on an apparatus of the type for setting an adhesive in corrugated paperboard during the manufacturing thereof, the apparatus comprising heating means for defining a heating surface and a conveyor belt positioned opposite the heating surface for advancing a corrugated paperboard sheet along a predetermined path of travel over said heating surface, said contact assembly comprising:

• a frame adapted to be positioned adjacent the back side of the conveyor belt and extending laterally thereacross;
• a plurality of contact shoes carried by said frame and arranged in side-by-side laterally extending relation, each of said contact shoes having a contact surface adapted for slidably contacting the back side of said conveyor belt;
• shoe mounting means for mounting each of said contact shoes to said frame so that each contact surface is adapted to be independently moveable along a predetermined path of travel generally normal to the heating surface;
• respective springs operatively connected between said frame and each of said contact shoes and adapted for independently urging the contact surface of each of said shoes against the back side of the conveyor belt, and
• stop means operatively connected between said frame and each of said contact shoes for defining a predetermined minimum spacing between each of said contact surfaces and a respective portion of said heating surface so that backing pressure is provided for a corrugated paperboard sheet having a predetermined minimum thickness and to thereby relieve pressure on the back side of said conveyor belt when the apparatus is operated without the corrugated paperboard sheet in place adjacent a respective portion of said conveyor belt.

A method for uniformly heating corrugated paperboard during the manufacturing thereof to set adhesive in the corrugated paperboard with an apparatus of the type including a plurality of heating chests arranged in side-by-side relation and defining a series of laterally extending heating surfaces, and a conveyor belt positioned opposite the series of heating surfaces, the method comprising the steps of:

• driving the conveyor belt to advance a corrugated paperboard sheet longitudinally along a predetermined path of travel over the heating surfaces;
• and
• slidably contacting and pressing upon a back side of the driven conveyor belt to urge the advancing corrugated paperboard sheet into substantially uniform contact with the adjacent laterally extending heating surfaces despite any thermally induced deflection thereof, said step of slidably contacting the back side of the conveyor belt comprising the steps of
• providing a series of contact assemblies associated with the back side of the conveyor belt, each contact assembly comprising a plurality of contact shoes arranged in side-by-side relation extending laterally across the conveyor belt, each of the contact shoes having a contact surface for slidably contacting the back side of the conveyor belt and being mounted to said frame for independent movement in a direction generally normal to the back side of the conveyor belt,
• biasing each of the contact shoes for independently urging the contact surface of each of the contact shoes against the back side of the conveyor belt, and
• defining a predetermined minimum spacing between each of said contact surfaces and a respective portion of said heating surface so that backing pressure is provided for a corrugated paperboard sheet having a predetermined minimum thickness and to thereby relieve pressure on the back side of said conveyor belt when the apparatus is operated without the corrugated paperboard sheet in place adjacent a respective portion of said conveyor belt.