THE PROBLEM OF EFFECT UPON BEARINGS.
A question arises as to the effect upon the bearings and the balls in them when any sort of shaft is used for chainless driving. Looking again at the cut of the shaft and adjacent parts, the reader will see that power applied on the pedal tends to roll the pinion directly away from the large gear, because if the pinion could roll clear away the axle would then be left free to turn; similarly, pressure at the back end tends to push apart those two pinions also. This pressure to separate comes upon the balls and the bearing surfaces, there being nothing else to take it. It is true that the draw of the chain, already explained, is thrown at once directly on the balls and the bearing surfaces, and that no large amount of trouble has been caused thereby, in all the last six years of use of chain driving. But it seems well settled that the old “League” bevel chainless did develop an experience of breaking balls and cups and cones, and it is claimed that bevel-gears produce a peculiar twisting strain on bearings. How much there is in this claim, and what precautions have been or can be taken by makers to meet the difficulty, time will show. Yet it should be said that the pin-roller gear, while free from any exposure to “end-thrust,” must take its chances with the other chainless models which have connecting shafts in respect to “side-thrust” on the bearings.