Sheet-feed tractor with resilient spring clamping subassembly

In a drive tractor for web material, the combination comprising:

• A. a chassis having a transversely extending support shaft aperture therein;
• B. a flexible endless belt extending about said chassis, said belt defining a closed path of travel thereabout and having an outer driving surface to engage the web material and an inner driven surface;
• C. a pulley rotatably mounted in said chassis and having it outer surface in driving engagement with said inner driven surface of said belt, said pulley having an aperture therethrough for receiving a drive shaft to effect rotation of said pulley and thereby said belt;
• D. guide means on said chassis overlying said endless belt along a portion of said closed path;
• and
• E. a unitary integrally molded spring clamp subassembly of resiliently deflectable material having a spring clamp element and a support element, said spring clamp element including a barrel portion extending outwardly from a side of said chassis and defining a passage for releasable reception of a support shaft there, said barrel portion having a first slot therein extending axially from the inner end of said barrel portion to a point spaced outwardly from the inner end thereof, said barrel portion having a second slot therein extending from the outer end of said first slot circumferentially for a segmental length around said barrel portion, said barrel portion having a third slot therein extending axially along said barrel portion from said second slot at a point spaced circumferentially from said first slot to the outer end of said barrel portion, said clamp means further including a pair of tab portions extending laterally outwardly from said barrel portion adjacent said first and third slots, said barrel portion has an arcuately shaped wall portion spaced oppositely from said circumferentially extending slot, resilient hinge portions adjacent each side of said arcuate wall portion and arcuate spring portions extending from each of said resilient hinge portions to said tab portions, whereby manually moving said tab portions toward one another enlarges said passage for releasable reception of a support shaft.