Endless chain apparatus for forming spur and helical gears

In apparatus of the type which includes an endless chain provided with stock removing tools arranged in at least one row for contacting a workpiece and for removing stock therefrom, the improvement in means for driving and controlling the endless chain characterized by

• tightening means for stiffening the endless chain as its passes through a work zone in which its tools make contact with a workpiece, said tightening means including
• a pair of gears mounted in meshing contact with the endless chain in spaced apart positions which define a flat plane in the cutting direction of movement of the endless chain, each of the gears of said pair of gears being mounted and fixed to a separate shaft, and including
• a third gear mounted on a main drive shaft for imparting driving moments to said pair of gears and endless chain,
• a fourth gear carried on said main drive shaft,
• a fifth gear carried on one of the shafts for one of said pair of gears, said gears being arranged so that said third gear meshes with and drives one of said pair of gears while said fourth gear carried on said main drive shaft is simultaneously rotated therewith, said fourth gear being arranged to mesh with said fifth gear fixed to the shaft associated with the other of said pair of gears, and wherein said fourth gear is releasably secured in its connection to said main drive shaft, so that the gear train can be adjusted and the articulated links of the endless chain can be stretched and tightened in the flat plane defined between the driven members, and
• driving means for moving said driven members in synchronism with each other.