US745735A - Air-brake. - Google Patents

Description

PATENTED DEC. 1, 1903 M. H. NEFF.

AIR BRAKE.

AiPLIOATION FILED MAY 21, 1903.

N0 MODEL.

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No. 745,735. iatented December 1, 1903.

UNITED STATES PATENT OFFICE.

MILTON H. NEFF, OF WATERTOWVN, NEW YORK, ASSIGNOR TO NEW YORK AIR BRAKE COMPANY, A CORPORATION OF NEW JERSEY.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 745,735, dated December 1, 1903.

Application filed May 21,1903. Serial No. 158,186. (No model.)

To all whom it may concern: it would be effective if said passage were left Beit known that I, MILTON H. NEFF, of Waconstantly open, as in prior constructions of tertown,'county of Jefferson, and State of New this general nature. York, have invented an Improvement in Air- The drawing shows in longitudinal vertical 55 Brakes, of which the following description, in section a triple valve of an air-brake apparaconnection with the accompanying drawing, tus embodying this invention, the parts being is a specification, like figures on the drawing shown with the emergency-valve mechanism representing like parts. in the same vertical plane with the triple- This invention relates to an air-brake apvalve mechanism, although in the practical 6o paratus, and has for its object the attainment construction of the apparatus this arrangeof very prompt individual application of the ment or relative location of the parts may be brakes on the several cars of the train. and commonly is different from that shown The invention is embodied inan air-brake in the drawing. apparatus having provision for locally vent- The triple valve proper actuated by the pis- 65 [5 ing the train-pipe for the purpose of hastenton 1 and comprising the exhaust-valve 4 for iug the serial application of the brakes on the connecting the passage 5 from the brake-cylseveral cars of a train, and is shown as apinder with the passage 6 to the atmosphere plied to a triple-valve structure of the kind and the valve 7 for controlling the flow of air shown in patent to A. P. Massey, No. 537,057, from the auxiliary reservoir 23 through the 70 dated April 9, 1895. As shown in said Maspassage 8 into the brake-cylinder are shown sey patent, the escaping train-pipe air when as of the same construction as in the Massey vented to produce quick serial operation acpatent, No. 537,057, the specific construction tuates a valve controlling a duct from the of these parts of the apparatus constituting auxiliary reservoir to the brake-cylinder, so no part of the present invention and it being 75 z 5 that the air is permitted to flow from the auX- unnecessary to describe their mode of operailiary reservoir to the brake-cylinder through tion, as it is well known to those acquainted said passage more copiously than through the with this art and is set forth in the said Maspassage employed in ordinary service or gradsey patent. uated applications of the brakes. The train-pipe vent-valve l3, controlling 80 The present invention relates mainly to the communication between the train-pipe air means for controlling the operation of the chamber or space 9 and the train-pipe escape train-pipe vent-valve, which, as shown in said port or duct 11, is actuated by the motor-pis- Massey patent, is operated by a piston exton 2, which is constantly exposed to trainposed to train-pipe pressure on one side and pipe air-pressure on one side and at the other 85 to the pressure of air contained in a small side to the pressure of the air confined in the chamber at the other side, there being a small small chamber 21, which in the normal posiduct or passage through or past the piston tion of the piston 2 occupied when the ventconnectingthe train-pipeandsaidsmallchamvalve 13 is closed communicates with the her, which duct remains constantly open, so train-pipe by a small duct or passage 33, 0

that the air may flow therethrough at all times formed in the stem 20 of said piston 2.

in either direction, according as the pressure The small chamber 21 containing air at at one or the other side of the piston preponone side of the vent-valve motor-piston 2 is derates. shown as formed Within the triple-valve pis- The present invention consists mainly in ton 1, which, together with the vent-valve 95 means for controlling the duct through the motor-piston 2, constitutes a compound pis vent-valve motor-piston, whereby said duct ton, the same as in the structure shown in is closed in response to a very rapid or sudthe Massey patent; but this construction is den fall in train-pipe pressure, and thus connot essential to the present invention, which fines the air in the small chamber at the other resides mainly in the arrangement and contoo side of the piston, so as to continue the effect trol of the duct 33. Said duct 33, as before of the said confined air beyond the time that stated, is formed in the piston-stem 20 and has a lateral opening 34 near the guide-passage in the casing of the valve in which the said stem 20 works. The result of this arrangement is that when the piston 2 has moved only a slight distance from its normal position in the direction to open the trainpipe vent-valve 13 and has dislodged the said valve 13 from its seat the opening 34 of the connecting-duct 33 has passed within the guide-passage for the piston-stem and is covered and closed thereby, and thus further communication between the train-pipe and the interior of the chamber 21 is cut 01?, so that the air in said chamber 21, that caused the valve-opening movement of the piston 2, remains confined in said chamber, and thus retains the piston 2 in the position in which it holds the vent-valve 13 open. But for such closure of the connecting-duct 33 34 the air would very quickly escape from the chamber 21, and thus permit the vent-valve 13 to be closed very shortly after it was opened, so that only a sudden puff of air would be permitted to escape from the train-pipe.

The escape of train-pipe air when the ventvalve is open hastens the application of the brakes on the next car of the train, producing the quick serial action that is exhibited in an emergency application of the brakes, and the escaping train-pipe air also serves in the apparatus herein shown to actuate an emergency brake-cylinder supply-valve 27, controlling the duct 29 30, which leads from the auxiliary reservoir to the brake-cylinder through the check-valve 28. Said brake'cylinder supply-valve 27 is actuated by a piston 14, working in a chamber 16, communicating with the train-pipe escape-passage 11 and having an outlet 15 to the atmosphere so located that the air in escaping through the vent-passage 11 will actuate the piston 14, and thereby unseat the valve 27, which is thus retained open while the train-pipe air is escaping through the passages 11 and 15. These means for operating the brake-cylinder supply-valve when the train-pipe'air is vented in an emergency application are embodied in the structure shown in the Massey patent and serve. to hasten the individual application of the brakes when having the quick serial action operation; but the appliances employed in the structure of the Massey patent for opening the train-pipe vent-valve open the same only for an instant, and the escaping train-pipe air consequently opens the brake-cylinder supply-valve 27 only for an instant.

By the construction forming the subject of the present invention, however, the closing of the duct 34, connecting the air-spaces at the two sides of the vent-valve motor-piston, causes the train-pipe vent-valve to remain open for a short interval of time, and the continued escape of train-pipe air acting upon the piston 14 will retain the brake-cylinder supply-valve 27 open long enough to permit the air to flow from the auxiliary reservoir to the brake-cylinder until the pressures therein are very nearly equalized, so that the maximum braking force is attained. Although it requires more than a mere instantaneous opening of the valve 27 to accomplish the full charging of the brake-cylinder, it requires that the valve should be retained open only a small fraction of a second, so that by the construction forming the subject of the present invention, in which the valve 27 is retained opened longer than it would be by the mere impact or blow of the piston 14, the brakes are individually applied with maximum force in an extremely short interval of time, as is especially desirable in connection with trains running at very high speed when an emergency arises demanding the stopping of the train in the shortest possible distance.

Except for the prolonging of the time that the vent-valve 13 is opened and the corresponding prolonging of the period in which the brake-cylinder supply-valve 27 is opened the operation of the apparatus shown is substantially the same as that of the apparatus shown in the Massey patent, which is well known.

Briefly described, the operation is as follows: In making service applications of the brakes the train-pipe air is permitted by the engineer to escape slowly, and the reduction in train-pipe pressure causes the triple valve proper to be operated by the auxiliary-reservoir pressure to close the exhaust from the brake-cylinder and admit air to the brakecylinder through the passage 8 from the auxiliary reservoir. With such slow reduction of train-pipe pressure the air will escape from the chamber 21 through the passage 33, so as to reduce the pressure in the chamber 21 substantially as fast as the train-pipe pressure is reduced, so that no appreciable pressure is brought to bear on the motor-piston 2 for opening the train-pipe vent-valve 13, which consequently remains unaffected in the service applications of the brakes. In making an emergency application the trainpipe air is permitted to escape as rapidly as possible, and the fall of train-pipe pressure takes place very rapidly, and the pressure in the chamber 21 does not fall so rapidly, owing to the smallness of the duct There thus arises a preponderance of pressure upon the motor-piston 2, tending to force its stem against the lever 17 of the vent-valve 13, which is thus opened and permits the trainpipe air to escape locally through the passage 11. The movement of the motor-piston 2, which thus opens the vent-valve 13, also closes the opening 31 of the duct 33 by carrying it into the guideway of the stem 2, and thus prevents, or rather greatly diminishes, the flow of air from the chamber 21,so that the airremains entrapped in said chamber 21 and retains the vent-valve 13 open for a short period of time. The volume of air in the chamber 21 is very small, and the air will escape from said chamher in ashort time by reason of the inevitable leakage around the piston oraround its stem 20, even though the passage 33 3i is closed, and consequently the vent-valve 13 will be closed shortly after it has been opened by the motor-piston, although its closing movement Will not instantly follow the opening movement, as is the case in the construction in which the passage through the motor-piston is constantly open. The guideway for the stem 20 of the vent-valve motor-piston 2,in connection with the passage 33 34, thus constitutes means for closing the duct from the small chamber 21, containing the air for actuating the motor-piston, said means for closing said duct being called into operation by a relatively sudden reduction in train-pipe pressure, and the duct remaining open when the reduction of train-pipe pressure is relatively slow; but the invention is not limited to this specific construction of the means for thus controlling the said duct.

Theinvention, which resides mainly in the novel means for controlling the train-pipe vent-valve motor-piston, is not limited to the specific construction of triplevalve structure, and it is not essential that the trainpipe vent-valve and its motor and the brakecylinder supply-valve and passage controlled by the escaping train-pipe air should be structurally associated with or constitute a part of the triple-valve structure.

I claim 1. The combination with the train-pipe,

auxiliary reservoir, and brake-cylinder of an air-brake apparatus; of a train-pipe ventvalve for permitting air to escape from the train-pipe; a brake-cylinder supply-duct from the auxiliary reservoir to the brake-cylinder,

and valve controlling said duct; and means actuated by the air escaping from train-pipe when vented for actuating said valve in the brake-cylinder supply-duct; and a motor-piston for the train-pipe vent-valve exposed to train-pipe pressure on one side and to pressure of air confined ina small chamber at the other side; a duct connecting the said small chamber with the space containing train-pipe air; and means for closing said duct in response to a sudden reduction in train-pipe pressure.

2. The combination with the train-pipe, auxiliary reservoir, and brake-cylinder, of an air-brake apparatus; of a train-pipe ventvalve for permitting air to escape from the train-pipe; a brake-cylinder supply-duct from the auxiliary reservoir to the brake-cylinder, and valve controlling said duct; means actuated by the air escaping from train-pipe when Vented for actuating said valvein the brakecylinder supply-duct; a motor-piston for the train-pipe vent-valve exposed to train-pipe pressure on one side and to pressure of air confined in a small chamber at the other side; a stem for said piston working in a guideway; and a duct from one to the other side of said piston opening in the portion of the stem that enters the guideway whereby said duct is closed when the piston is moved by preponderance of pressure in the small chamber.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

MILTON H. NEFF.

Witnesses:

JNo. F. MALONEY, R. HOLDEN.

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