US593923A - George h - Google Patents

Description

{No Model.)

v G. H. COOPER.

AIR MOTOR.

No. 593,923. Patented Nov. 16, 1897.

WITNESSES I /N VE N 70/? A TTOHNEYS.

UNITED STATES PATENT mar.

GEORGE H. COOPER, OF NEW WESTMINSTER, CANADA.

AlR-MQTOR.

SPECIFICATION forming part of Letters Patent No.'593,'923, dated November 16, 1897.

Application filed April 14, 1897.

, act description.

My invention relates to air-motors, particularly such as are employed. for propelling street-cars. v v

The object of my invention is to provide an air-motor in which a compound effect may be obtained, the air being used at the same pressure it has in the reservoir. Provision is also made for applying air under the same pressure to two or more pistons after the pressure in the reservoir has fallen so much as to render a compound effect impracticable or uneconomlc.

Another object of my invention is to utilize the surplus power not required for propulsion to operate a compressor for the purpose of partly replenishing the supply of air in the reservoir. I also provide improved means for governing the speed of the motor. The compressor above referred to also forms a very efficient brake.

The features of construction whereby the above-indicated results are obtained will be fully described hereinafter and the novelty pointed out in the appended claim.

Reference is to be had to the accompanying drawing, which is a longitudinal section of an air-motor constructed according to my invention.

A is the supply-pipe connected to the airreservoir. (Not shown.)

B is a throttle-valve or other suitable valve located in the supply-pipe, said valve being operated to start or stop the motor.

The supply-pipe A leads tofthe chest 0, in which moves the slide-valve D of the highpressure cylinder E, having inlet-ports E and an exhaust-poptflsubstantially like those of an ordinary steam-engine. The exhaustport E is connected by a pipe or channel F to the chest 0 of the slide-valve D, controlling the admission of air to the second or me-' dium-pressure cylinder E". This cylinder is of larger diameter than the hi gh-pressure cylinder E. The exhaust-port E of the second cylinder is .connected by a channel or pipe F $eria1 No. 632,101. (nomad) cylinder J of an air-compressor,said-compressor having port-s K K at its upper end, which ports are connected by means of pipes L to the supply-pipeA at a point between the reservoir and the valve B. The pipes Lhave outwardly-opening check-valvesM. Between said valves and the ports K K the pipes L are connected to branch pipes N, having inwardly-opening check-valves O, and the two pipes N are connected into one, as shown at N, their connection with the atmosphere beingcontrolled by a valve P, placed within ready reach of the operator. The supply- -pipe A is also directly connected to the slidevalve chests O and O of the medium-pressure and low-pressure cylinders E and E respectively, the connection being efiected by means of pipes Q and controlled by valves Q, so that the compressed air may be admitted to the cylinders E and E directly from the supply-pipe A, if desired.

The operation of my air-motor is as follows: The valve B being opened and the valves Q closed, air is admitted to the highpressure cylinder E under the same pressure it has in the reservoir. The air operates the piston H in the well-known manner and then escapes through the pipe F to the mediumpressure cylinder E, where it operates the piston H and finally travels in a like manner-through the pipe F into the low-pressure cylinder E, whence it escapes to the atmosphere after actuating the piston H The reciprocating piston-rod I actuates the piston H of the compressor, forcing the air from the cylinder'J at each stroke through one of the, pipes L to the air-reservoir. At each stroke air is drawn into the cylinder J through one of the pipes N, and by opening the valve P more or less the operator can control the re sistance opposed to the motion of the piston H and thereby regulate the speed of the car.

It will be understood that the compressor is operated only by the excess of power above that required for propulsion. The compressor will act as a brake, particularly on a downgrade, and will, moreover, partly replenish the supply of air in the reservoir.

It will be evident that the air is used expansively in the cylinders E and E the motor shown being thus a triple-expansion motor. The same construction could of course be applied as well to a motor having two, four, or more cylinders receiving the air successively.

When the pressure in the reservoir becomes so low that little or no power is obtained by expansion in the low-pressure cylinder E, I open the valve Q, leading to the mediumpressurc cylinder E so that the piston H (of larger area than the piston H) becomes the high-pressure piston and only the cylinder E is a compound cylinder. Aftera further reduction of pressure in the reservoir air may be admitted directly to the largest cylinder E The advantages of myimproved motor are an economic utilization of the air at the reservoir-pressure, dispensing with a reducingvalve, an easy control of the speed, a powerful braking action,the change from compound to direct action as the pressure falls in the reservoir, and the partial replenishing of the air-supply. By connecting the pipe L to the supply-pipe A instead of directly to the reservoir I secure the advantage that the heated air from the compressor enters the motor-cylinders first, and thus prevents the formation of ice.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- An air-motor having a cylinder and a piston therein, an air-supply channel connected to said cylinder, a compressor operated by said piston, and a valved compressed air-channel leading from said compressor directly to the air-supply pipe to partly replenish the supply of air, substantially as described.

GEORGE ll. COOPER.

WVitnesses: v

CHARLES E. RoBsoN, JAMES G. SMITH.

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