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United States Patent Office»

K. H. C. PRESTON, OF MANLIES, NEW YORK, ASSIGNOR TO Ε. P. RUSSELL, OF SAME PLACE.

IMPROVEMENT IN HARVESTERS.

Specification forming part of Letters Patent No. 33,975, dated December 17, 1861.

To all whom it may concern:

Be it known that I, King H. C. Preston, of Manlius, in the county of Onondaga and State of New York, have invented a new and useful Improvement in Harvesters; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing, which forms a part of this specification.

My improvement in harvesters consists in transmitting the requisite rate and force of motion from the driving-wheel A to the crankshaft C through the medium of the series of rollers e e which are pivoted to the face of the said driving-wheel, and the tapering single screw-thread d, which proj ects from the periphery of the said crank-shaft.

By employing but a single screw-thread upon the crank-shaft C for the aforesaid series of rollers e e to act upon, and by giving the said screw-thread a gradually-tapering shape, lam enabled to place the crank-shaft in such aposition that its axis will be exactly opposite to a portion of an imaginary circular line passing through the centers of the pivots of each of the rollers e e, and I am also enabled to place the saidrollers in such near proximity to each other that an unusually-smooth niovementis imparted to the crank-shaft, and everything like “ backlash” in the working of the said screw-thread d and the rollers e e is.entirely prevented. If the screw-thread d were of uniform thickness -from pnd to end, the rollers e e would have to be jilaced at a'much greater distance from each other, and consequently a great .amount of backlash would be the result.

The position of the crank-shaft with relation to the pivots of the series of rollers e e, before referred to, enables me to act upon the thread d of the crank-shaft by means of rollers, instead of oval-headed pins, as is the case in the “ Haviland harvester,” and the said position of the crank-shaft in my machine also enables me to use rollers e e which have tapering bearing-peripheries of substantially the shape represented in the drawings.

The tapering screw-thread d I shall generally cast in one piece with a tube. B, and then fit the said tube to the crank-shaft in. such a manner that it will only cariy the said shaft around with it when it is rotated by means of the forward movement of the driving-wheel A. The tapering-shape of the screw-thread d enables the pattern of the thread-bearing tube B to be easily drawn from the sand during the process of molding the same preparatory to casting.