ATTEMPTS TO DEAL WITH CHAIN FRICTION.
THAMES
TWIN-ROLLER.
The friction of the chain is of three sorts and at three places. First is the “block” friction, where and when a few blocks at a time enter and leave contact with the sprockets on the upper side, the action on the lower side (except in back-pedalling) being so free that it need not be taken into account; the second is the “pin” friction, made by the side links as they turn on the rivets; the third is where and when the ends of the links rub on the sprockets while bending.
MORSE ROLLER-JOINT
CHAIN.
There have been many attempts to turn these rubbing frictions into rolling movements. Only a few months ago application was filed for an English patent on putting balls into the chain joints; but the great number of joints and the small size of the parts make this plainly impracticable. A far better and really practical thing is the [Morse roller-joint chain], made in Trumansburg, N. Y., and now in use on several makes, among them the Sterling; it would undoubtedly make its way faster into use except that the parts have to be a little larger, and therefore the pitch a little more than the regular inch, and so the sprockets must be cut specially; sprockets of inch pitch can, however, be recut to fit. As the illustration shows, the principle of this joint is the same as that of scales—the knife-edge bearing. The pin with the two edges is fast to the side link; the pin with one edge is dropped in loosely and the two rock on each other instead of rubbing, producing no wear and so not needing lubrication. The maker claims a frictional loss by his chain of less than one per cent. of the power developed; there is always some loss, it should be observed, and so the advertisement of the Eadie roller-chain, that “it transmits practically 100 per cent. of the force applied,” is somewhat too enthusiastically worded.