Popular Science Monthly 



Applying a Change- Speed Device 

 to an Automobile Clutch 



INVENTORS have made many efforts to 

 provide a change-speed mechanism for 

 automobiles in order to dispense with the 

 unsatisfactory gears now universally used. 

 A system, to be effective, should be so 

 arranged as to avoid intermesh'ing gears. 

 For availability of control the ratio of speed 

 should be indefinite, the speed increased or 

 decreased by the simple movement of a 

 wheel or lever, and devoid of friction while 

 in operation. 



The hydraulic system has been exploited 

 in Various ways, but 

 the devices, as here- 

 tofore constructed, 

 showed certain dis- 

 advantages, namely: 

 the liability of the 

 expansion of the oil 

 to such an extent as 

 to injure the device 

 or greatly lessen its 

 efficiency; the in- 

 ability to make the 

 device small enough 

 for easy installation ; 

 the great weight in- 

 volved ; the necessity for using both pumps 

 and motors, and the slip due to leakage past 

 the working parts. 



The foregoing objections appear to be 

 overcome by a new development of the 

 hydraulic drive, which utilizes the clutch as 

 one element in the change-speed mech- 

 anism. The entire device occupies but a 

 little more space than the male part of the 

 standard clutch, which it displaces, as no 

 clutch is necessary in using a car with this 

 invention. 



The drawings give a comprehensive view 

 of the device, as all of the elements are 

 shown in the two views. The body of the 

 device is a cylindrical shell, the perimeter of 

 which fits the standard clutch element 

 inside of the fly-wheel. This is held in 

 place either by friction or by means of cap- 

 screws, so that it is permanently fixed to 

 the wheel. 



The rear side of the shell has a removable 

 plate, the mechanism for changing the 

 speed being secured to the inner surface of 

 the plate, while the reversing mechanism is 

 on the outside of the plate. 



Within the shell are four radially- 

 disposed cylinders, each cylinder having 

 within it a piston, suitably packed with 

 rings, following the usual practice. The 



The speed is changed by air pressure applied 

 to the four cylinders used instead of the clutch 



775 



stub-shaft, which enters the rear plate of 

 the shell, has a single crank to which the 

 four connecting rods are secured, so that 

 the pistons have a successive motion to and 

 fro as the shell turns, provided, of course, 

 that the oil is confined in the pistons. 



The head, or outer end of each cylinder, 

 has ports on two opposite sides, the outer 

 surface of each cylinder, along the ports, 

 being planed flat and covered by slide 

 valves which move axially, or parallel 

 with the stub-shaft. The valves are re- 

 shaped and provided with suitable openings 

 to co-ordinate with the ports of the cylin- 

 ders, each valve being 

 designed to open or 

 close the ports of 

 two adjoining cylin- 

 ders. To effect this, 

 each L- valve has a 

 stem which passes 

 through the remov- 

 able plate of the 

 shell, the outer ends 

 of these stems being 

 rigidly attached to a 

 rim which, although 

 it turns with the 

 shell, is, neverthe- 

 less, easily adapted to connect with an 

 operating lever. 



It is obvious that, as the cylinders are 

 rigidly attached to the shell, the stub-shaft 

 will not turn if oil is permitted to freely 

 pass in and out of the cylinders. The only 

 effect in such a case would be to produce a 

 reciprocating motion of the pistons. When, 

 however, the driver of the car moves 

 forward the lever which causes the L- valves 

 to travel inwardly, and the ports of the 

 cylinders are closed thereby, the pistons are 

 restricted in their reciprocal motions, and 

 the shaft turns, the rate of speed, relative to 

 the engine speed, being dependent on the 

 quantity of oil which is displaced at each 

 revolution. If the ports are entirely closed, 

 then the stub-shaft will travel at the same 

 rate of speed as the engine-shaft. 



It will thus be seen that there is no 

 appreciable loss of power, and the slight 

 amount of oil which escapes past the valves 

 imparts a resiliency, or flexibility, to the car 

 comparable to the electric or magnetic 

 drive. There is not a single gear in the 

 entire mechanism for driving the car 

 forward. 



For reversing, however, a train of gears is 

 employed; or conical friction wheels may 

 be used. A small bevel gear is fixed to the 



