A NEW MOTOR CYCLE ENGINE.—The engine illustrated in the accompanying engraving represents three years of work in perfecting a design which should be perfectly suited to the requirements of the motor bicycle. It is a very light engine, weighing only 28 pounds and developing 214 horse-power on the brake. Its principal claim to novelty lies in the fact that the cylinder is screwed into the crank case instead of being fastened thereto with lugs and bolts. The crank case is formed with an internally threaded cylinder. A setscrew threaded through one side of the crank case bears against the threaded portion of the cylinder to prevent it from being unscrewed. When thus locked there is no danger of the cylinder working loose, and thus are. avoided the objections to the usual construction in which the bolts and nuts are often loosened by the vibration of the machine. The screw joint permits of a lighter, as well as a more lasting construction. The power of the motor is sufficient to climb grades of -from twenty to thirty per cent. It may be applied to standard bicycles of 22 or 24-inch frame. ANNULAR BALL BEARING.—A recent improvement, particularly designed for motor cycles, though also adapted for automobiles, is an annular ball bearing with two rows of balls running in separate ball races and designed to take both radial load and end thrust. The device is, in reality, two bearings in one, and it is claimed that it will bear twice the radial load of other bearings of the same size, and also an end thrust nearly equal to its radial load capacity. Our illustration shows the bearing broken away to reveal the interior arrangement. It will be noted that the balls are kept in place j by means of a separator ring which is j V-shaped in cross-section, and is formed . with semi-circular indentations along the j two edges which fit over the balls. The separator ring rests on the balls without friction at any stationary point. The two rows of balls are designed to distribute the load evenly between them. The bearing may be used as a substitute for end thrust and radial load bearings at present used in most automobiles. In such places as a bevel gear bearing where the line of strain is at right angles with the base of the gear teeth, the thrust is intermediate between the radial and end pressure, and with a bearing, such as here illustrated, this diagonal thrust may be taken care of to the best possible advantage. TWO-SPEED GEAR.—The primary object of the gear illustrated herewith is to allow a motor cycle to run on the high speed without friction. This is accomplished by bringing the friction band into engagement with the pulley wheel and thus permitting practically the en- tire mechanism of the gear to rotate as a single pulley. The usual fiber friction surfaces are dispensed with and the frictional engagement takes place between metal surfaces. When set for low speed the friction band is held stationary and the power is transmitted through step-down gearing connected with the band. The construction will be understood by referring to the sectional views. The power shaft is shown at A, and it carries a sleeve B to which is keyed the pulley O. The latter is provided with a V-shaped groove into which the friction band D is adapted to fit. The friction band is mounted to slide in axial direction on a drum E, to which it is secured by means of pins d on the periphery of the drum and engaging slots in the friction band. A series of spring-actuated plungers e serve to press the band D against the pulley C. At the opposite edge of the band D there is a flange which engages a slot formed in the inner periphery of an operating band F. The latter is provided with ratchet teeth f adapted to engage ratchet teeth g on a stationary band G secured to the crank box. Owing to the ratchet form of the teeth when the operating band F is rotated, it is moved axially away from the stationary band G, withdrawing the friction band j) from the groove in the pulley C. Keyed to the shaft A is a pinion H which engages a gear wheel J. The latter is Keyed to a pinion K, which is mounted on a shaft J journaled in the drum E. The pinion K in turn engages a gear L. formed on the sleeve B. When the mechanism is set for high 345 speed the operating band F is turned to permit the friction band D to engage the pulley. No relative motion can take place between pinion K and gear L because the drum E and pulley 0 are locked together by the band D, hence the power transmitted from shaft A through pinion H to the gear 7 serves to turn the drum and pulley as a single pulley. For the low speed the friction band D is withdrawn by a turn of the operating band F, and brought into engagement with the stationary band G. This serves to keep the drum E stationary. The power of shaft A is then transmitted through pinion H, gear I, pinion K, to gear L on the sleeve B, thus driving the pulley 0, which is keyed to this sleeve. The gearing is arranged to step down the speed the required amount. If the operating band is moved sufficiently to carry the friction band D clear of the pulley 0 and fixed band G, the engine will run free, for the drum E will then turn idly without transmitting any power to the pulley O. The inventor of this ingenious speed gear is Dr. Sherman T. Lewis, of Room 1018 Hartford Building, Chicago, Ill.
This article was originally published with the title "Some Improvements for the Motor Bicycle" in Scientific American 97, 19, 344-345 (November 1907)