THE BROWN ROLLER-SPROCKET.
While giving due credit to the [Morse chain], we must point out that it attempts to deal with only the second of the sources of friction above stated. The [Brown roller-sprocket] apparently attempts to deal with all three, involving an action unlike any other. It has a rim with a double flange, in which are inserted hardened steel rollers three-quarters of an inch in diameter, running on hardened steel bushings, which in turn are free to revolve on hard steel rivets. The chain is 3⁄16 and of 1¼ inches pitch; it is reversible and the side links are longer than the blocks, which in action ride over the rollers, reaching from one roller to another without touching the rim of the sprocket. Instead of the block rubbing on the tooth as it leaves the sprocket, it turns the roller and rolls off; thus, if the stress of use develops no other action of the parts than is claimed, the only rubbing friction is at the axes of the rollers, where the motion is comparatively slight. A drawback is that the sprockets must be very large in order to get a goodly number of rollers in the rear one, and the same difficulty of being special in both sprocket and chain, which retards some other devices in the market probably affects this one.