Drive system for hay harvesting and conditioning machine

A crop harvesting and conditioning machine of the type adapted to be drawn by a tractor having a power take-off, comprising:

• a transversely arranged header assembly including a main frame, rearwardly positioned support wheels, and a sickle mower positioned along the front of said frame;
• a tongue subframe, a pivotal mount between said subframe and one end of said main frame sidewalls and having at its other end a drawbar coupling having provision for attachment to said tractor;
• a pair of crop conditioning rolls rotatably mounted relative to said main frame on generally transverse axes above and behind said mower, each roll having a shaft extending axially outward therefrom, said shafts allowing rotatable journalling of said rolls to said machine;
• lever arm plates swingably mounted on the sidewalls of the main frame, the lower of said rolls being journaled on a fixed axis relative to said main frame and the upper of said rolls being journaled at its ends on said lever arm plates;
• spring means adjacent each end of said upper crop conditioning roll for exerting a compressive force urging the crop conditioning rolls together, one end of each of said spring means being anchored to said frame, the other end of each of said spring means being attached to the swingable end of one of said lever arm plates;
• a transmission mounted on said subframe and coupled to said power take-off, said transmission including an output element having an axis coaxial with said pivot;
• belt drive means for transferring power from said output element to said upper crop conditioning roll, said belt drive means including a pulley attached to the axially extending shaft on the end of said upper crop conditioning roll;
• and
• an arrangement of means for utilizing said upper crop conditioning roll to drive said lower crop conditioning roll, said arrangement of means comprising:
• a driving sprocket on the outward extending shaft of said upper crop conditioning roll,
• a driven sprocket on the outward extending shaft of said lower crop conditioning roll,
• a yieldably restricted slide element attached to one of said spring means and moving in synchronism with any displacement of the companion lever arm plate,
• a plurality of chain positioning elements of which one is rotatably mounted on said slide element, and
• an endless chain entrained around said sprockets and chain positioning elements, said one chain positioning element being both within the chain periphery and secured to said slide to move linearly to compensate for sprocket chain slack variation introduced as said crop conditioning rolls are separated in response to varying amounts of crop material passing therebetween.