STERLING CHAINLESS
CONNECTING SHAFT.
These special features of the [Sterling chainless construction] are shown in the [accompanying illustrations]. The rear fork on the gear side has a boss in which the axle is screwed. The opposite fork end has a circular opening larger than the cross section of the axle and a short slot for inserting the axle. A threaded sleeve fills the circular opening, which is also threaded, abutting against the outside face of the fork end with a shoulder. A lock-nut fits upon the inner projecting portion of the sleeve. In assembling, the wheel is first mounted on the axle; the latter is then screwed into the fork end on the gear side by applying a wrench on the hexagonal portion of the axle projecting beyond the hub on the opposite side. When the gears mesh properly and the lock-nut has been placed on the left side end of the axle, the threaded sleeve is placed in position and the lock-nut is tightened.
The lines of mesh along the teeth of bevel-gears or radial gears, as they are more properly called, always point to a common centre when the gears are in proper engagement. The common centre in the front row gears of a chainless bicycle is at a point in the axis of the crank shaft; but if the two front pinions were interchanged they would cease to have a common apex, and could not be made to co-operate. With the driving shaft at right angles with the crank shaft and the rear axle, the pinions in front as well as in the rear could be made interchangeable only at a pitch of forty-five degrees, which would make the interchangeability of no value. With the driving shaft at another angle with the rear axle, as in all chainless bicycles, it is possible to so proportion the two rear pinions that the mesh lines point to the same centre whether the smaller pinion is on the hub or on the driving shaft. The possibility is limited to two sets of interchangeable gears for any given angle of the driving shaft, which has been taken advantage of by the Sterling Company.
The Sterling Chainless will be made in two models; one for men and a drop frame design for women. Each lists at $125.
THE DAYTON CHAINLESS.
This chainless wheel is constructed on an entirely new and distinct principle by which all bearing points of the transmitting mechanism are incased and made absolutely proof against dust, dirt and weather conditions. The most noticeable part of this construction is the transmission of motive power to the rear hub, equally on both sides of the frame, this action being continuous at all times. It therefore gains over a bevel-gear construction not only the advantage of eliminating the friction always present in a cog gear, but also removes the danger of springing the rear forks out of line by a sudden strain, which has been so difficult in all chainless wheels heretofore produced.
The crank-hanger of this wheel consists of a steel box in which is located the gearing mechanism. Within this box are two double-flanged, notched pulleys, over which runs a link belt especially made and designed for this construction. These pulleys are placed on the central line of the bicycle, the larger or front pulley which corresponds to the driving sprocket on the chain wheel, being secured to the driving crank axle by means of a thread and held in place by a reversed threaded lock-nut. The smaller or rear pulley is made in one piece with a crank axle, having on each end short cranks set quartering.
On each side of the frame, a Pitman or connecting rod extends from the short crank on the auxiliary axle in the crank box to a similar crank attached to each side of the rear hub, a dust-proof ball bearing being provided at each end of the Pitman rod. The rear hub being journaled in ball bearing in the rear fork and fittings, is forced to revolve in unison with the auxiliary axle by the connection formed through the corresponding cranks and connecting rod on each side. A dead centre is prevented by the Pitman crank being set quartering, as explained. An eccentric adjustment is provided at the front bearing of each Pitman rod, making it possible to slightly vary the length of the rod when necessary. This adjustment can be effected as easily as the adjustment of a chain on the ordinary type of wheel. The adjustment of the driving belt is also readily effected by mounting the front or driving crank shaft in an eccentric on the hanger boxing. The tread of the machine is made as narrow as possible by the use of flattened tubing in the rear forks, and by cranking the driving rods, the crank portion being reinforced by a forged connection. The outward appearance of the wheel is attractive, and in quality of material and workmanship, and elegance of finish, it upholds the standard heretofore maintained on all products of the Dayton factory. It is claimed that this construction produced less friction than any bevel-gear chainless wheel, in addition to the other important features noticed.