Paper feed tractor with compensating drive pulley

In a web feeding assembly, the combination comprising:

• A. a web feeding drive apparatus having spaced, parallel extending drive and support shafts;
• B. a pair of tractors each mounted on said pair of shafts in axially spaced relationship therealong, each of said tractors having:
• (i) a chassis having a pair of spaced transversely extending apertures therein, at least one of said apertures being adjacent one end of said chassis said shaft extending through, said at least one aperture and said support shaft extending through the other of said apertures;
• (ii) a flexible endless belt extending about said chassis generally perpendicularly to the axes of said apertures and shafts, said belt defining a closed path of travel thereabout and having an outer driving surface adapted to engage web material and an inner driven surface;
• (iii) a pulley rotatably mounted in said at least one chassis aperture and in engagement with the driven surface of said belt, said pulley having an aperture therethrough receiving said drive shaft therein to effect rotation of said pulley and thereby said belt, said pulley having resiliently deflectable means for accommodating irregularities in said drive shaft and variations in spacing between the axes of said drive and support shafts during operation of each of said tractors, said deflectable means defining at least a portion of said shaft receiving aperture and resiliently bearing upon said drive shaft over a portion of its length, said deflectable means providing a portion of reduced cross section therefor over the area bearing upon said shaft, whereby said drive shaft may produce deflection of said deflectable means.