Tensioning device

Claim 1

IN A TENSION DEVICE FOR USE WITH A THERMOCOMPRESSION LEAD BONDING MACHINE OF THE TYPE HAVING A BONDING TOOL MOVABLE TO URGE THE LEAD WIRE INTO ENGAGEMENT WITH THE ELEMENT TO WHICH THE LEAD WIRE IS TO BE BONDED, A SPOOL HAVING A QUANTITY OF LEAD WIRE WOUND THEREON, MEANS FOR ROTATABLY MOUNTING THE SPOOL FOR ROTATION ABOUT A HORIZONTAL AXIS AND FOR MOVEMENT SOLELY IN VERTICAL AND HORIZONTAL DIRECTIONS, THE SPOOL BEING FORMED WITH AN ANNULAR RACE WHICH HAS AN AXIS WHICH IS COINCIDENT TO THE AXIS OF ROTATION OF THE SPOOL, AT LEAST TWO FREE-RUNNING BALLS DISPOSED IN THE RACE IN FRICTIONAL ENGAGEMENT WITH EACH OTHER, THE BALLS AND THE SPOOL ASSUMING A POSITION SO THAT THE BALLS ARE IN THEIR LOWERMOST POSITION WHEN THE END OF THE LEAD WIRE IS FREE, THE BALLS MOVING UPWARDLY WITH THE SPOOL WITHOUT ROTATION BECAUSE OF FRICTIONAL ENGAGEMENT BETWEEN THE BALLS AS THE LEAD WIRE IS UNWOUND FROM THE SPOOL BY ROTATION OF THE SPOOL TO A PREDETERMINED ANGLE ABOVE THEIR LOWERMOST POSITION TO PROVIDE A TENSIONING FORCE ON THE WIRE, THE BALLS AFTER THE SPOOL IS ROTATED BEYOND SAID PREDETERMINED ANGLE ROLLING AGAINST EACH OTHER DOWN THE ANNULAR RACE BUT ABOVE SAID LOWERMOST POSITION BECAUSE OF FRICTIONAL ENGAGEMENT BETWEEN THE BALLS TO PROVIDE A PREDETERMINED UNIFORM TENSION ON THE LEAD WIRE AS IT IS UNWOUND FROM THE SPOOL, THE FREERUNNING BALLS REMAINING ABOVE THEIR LOWERMOST POSITION BECAUSE OF FRICTIONAL ENGAGEMENT BETWEEN THE BALLS WHEN THE SPOOL HAS STOPPED TO APPLY A PREDETERMINED UNIFORM TENSION TO THE LEAD WIRE EACH TIME THE SPOOL HAS STOPPED, THE BALLS AND THE SPOOL ON WHICH THE BALLS ARE MOUNTED ROTATING IN A DIRECTION OPPOSITE TO THE NORMAL DIRECTION OF ROTATION WHEN THE LEAD WIRE IS RELEASED TO REWIND A PORTION OF THE LEAD WIRE ONTO THE SPOOL.