US1832893A - Fluid pressure braking apparatus - Google Patents

Description

3 Sheets-Sheet l A. CHEVILLQT FLUID PRESSURE BRAKING APPARATUS Filed Oct. 1, 1928 Nov. 24, 1931.

INVENTOR ALFRED CHEVILLOT 1931- A. CHEVELLOT 1,832,893

FLUID PRESSURE BRAKING APPARATUS Filed Oct. 1, 1928 3 Sheets-Sheet 2 Fig.2

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ATTORNEY "ALFRED CHEVILLOT FLUID PRESSURE BRAKING APPARATUS Filed Oct. 1, 1928 3 Sheets-Sheet 5 INVENTOR ALFRED CHEVILLOT ATTOR EY Patented Nov. 24, '1931 PATENT OFFICE ALFRED CHEVILLOT, 0F PARIS, FRANCE, ASSIGNOR TO THE WESTINGHOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA ruin) PRESSURE BRAKING APPARATUS Application filed. October 1, 1928, Serial No. 309,432, and in Great Britain October 28, 1927.

This invention relates to' fluid. pressure braking apparatus of the kind comprising a controlling or distributing valve adapted to be operated by variations in train pipe pressure to control the supply of fluid under pressure to and its release from the brake cylinder.

A controlling valve of the character above indicated usually comprises a movable abutment subject to the opposing pressures ob taining in the train pipe and in a reservoir or chamber which may or may not constitute a source of fluid for supply to the brake cylinder and is generally arranged to contain fluid at the train pipe pressure being usually charged from the train pipewhen the abutment'is in a position corresponding to the release of the brakes. During the restoration of the train pipe pressure to its normal value in order to effect the release of the brakes by the movement of the abutment of thecontrolling valve to the release position above referred to, there is a possibility of the reservoir or chamber being charged to a pressure greater than that desired owing to a local 2 rapid release of the brakes the train pipe pressure is rapidly restored to its normal value or is temporarily increased to some extent above this value and the invention accordingly has for its object to provide arrangements whereby the establishment of a pressure in excess of that desired in the reservoir or chamber may be prevented inspite of local or generalexcessive pressure in any part of the train pipe.

According to the principal feature of the invention the supply of fluid underpressure to the chamberor reservoirjis arranged to be effected through a valve mechanism which permits such supply only when the train pipe'pr'essure is at its normal or stable value or materially restricts such supply until such conditions have been attained. This valve mechanism is preferably arranged to cut off or restrict communication between the train pipe and the chamberor reservoir when the train pipe pressure is reduced during an application of the brakes or during the restoration of the train pipe pressure to eflect the release of the brakes until this release or a considerable portion thereof has been completely effected. By this arrangement the pressure in the chamber or reservoir is caused to correspond to the stable pressure normally obtaining within the train pipe under running conditions, and the pressure in the chamber or reservoir as a controlling factor in the operation of the controlling or distributing valve is thus maintained substantially constant and uniform throughout the sure obtained in the brake cylinder and an opposing pressure such as spring pressure so as to cut ofi communication with the chamber or reservoir so long as the brake cylinder pressure predominates over the opposing pressure and this valve mechanism may be arranged to be combined with or constituted by a valve device for controlling the rate of re-charging of the chamber or reservoir where this is employed as a source of fluid for supplying the brake cylinder, the rate of re-charging being dependent upon the pressure obtaining within the chamber or reservoir and upon the pressure obtaining'within the brake cylinder at any time during the application or releaserof the brakes.

The invention will now be described, by Way of example only, with reference to the accompanying drawings, Figure 1 of which is a diagrammatic View ofa fluid pressure braking system embodying the invention,

Figure 2 being a view of a modification, and Figure 3 is a diagrammatic view of a further modification of the invention.

, Referring first to Figure 1, the braking apparatus comprises a triple or distributing valve device 1 adapted to control the supply of fluid under pressure to an auxiliary reservoirv 2 and a brake cylinder 3 and the release of fiuid under pressure from the latter under the influence of variations in the pressure in the train pipe 4 of the apparatus. The rate of supply of fluid under pressure to the auxiliary reservoir 2 and its release from the brake cylinder 3 is arranged to be controlled by a release valve device 5 in such a manner that the rate of re-charging is dependent upon the pressure obtaining within the auxiliary reservoir 2 and upon the pressure obtaining within the brake cylinder 3 at any time during the application or release of the brakes.

The triple valve device 1 comprises a piston 6 subject continuously on one side to the pressure in the train pipe 4, which is connected to the chamber 7 on the right hand face of the piston through a conduit 8, and on the other side to the pressure in the auxiliary reservoir 2. The piston 6 is adapted to operate a slide valve 9 controlling communication from the brake cylinder 3 through a conduit 10 and a conduit 11 to a chamber 12 in the release valve d vice 5. The piston 6 is also arranged when in its release position to establish communication between the train pipe 4 and the auxiliary reservoir 2 through conduits 13, 14, a chamber 15 in the release valve device 5 and a conduit 16, this com munication being cut off by the piston 6 during an application of the brakes.

The release valve device 5 comprises four chambers 12, 15, 17 and 18 by three flexible diaphragms 19, 20 and 21, the diaphragm 19 being subject to brake cylinder pressure in the chamber 12 during release of the brakes communication between this chamber and the atmosphere being controlled by a valve 22 mounted on a stem 23 to which the three diaphragms are secured. The diaphragms 19 and 20 are both continuously subject to the auxiliary reservoir pressure in the chamber 15, the diaphragm 21 being subject to atmospheric pressure in the chamber 18. The diaphragms 20 and 21 are also subject to the pressure in the chamber 17 which is connected through a conduit 85 to a control chamber 24 which is connected through a conduit 25 and a valve device 26 and the triple valve device 1 to the train pipe 4. The valve device 26 comprises a slide valve 27 adapted to be actuated by a piston 23 subject to brake cylinder pressure in the chamber 29 of the device and to the pressure of a spring 30 located in a chamber 31 on the other side or the piston. Communication from the train pipe through the chamber 7 and conduits 13 and 25 to the control chamber 24 is arranged to be cut off by the slide valve 27 so long as there is a predetermined minimum pressure in the brake cylinder 3, which is connected to the chamber 29 through a conduit 32.

The operation of the apparatus is as follows Assuming that the braking system has been charged to the normal pressure and that the triple valve device 1 and its associated valve devices 5 and 26 are in their release positions when the train pipe pressure is reduced in order to effect an application of the brakes the piston 6 of the triple valve device is moved under the influence of the pressure in the auxiliary reservoir 2 to cut off communication between the brake cylinder 3 and the atmosphere through the release valve 22 of the release valve device 5 and between the train pipe 4 and the auxiliary reservoir 2 and control chamber 24, fluid under pressurebeing supplied from the auxiliary reservoir 2 to the brake cylinder 3 through a conduit 33, a chamber 34 in the triple valve device 1 and the conduit 10.

In order to release the brakes the train pipe pressure is raised to normal pressure and in order to raise the train pipe pressure to normal pressure it may be desirable temporarily to increase the train pipe pressure above its normal value. In the event of the train pipe pressure being raised above its normal value by design or owing to a local surge of excessive pressure in the train pipe for any reason, the triple valve piston 6 is rapidly moved to its release position (as illustrated in the drawings), in which the brake cylinder 3 is connected through the conduits 10 and 11 to the chamber 12 in the release valve device 5 and thence to the atmosphere past the release valve 22. Communication is also established from the train pipe 4 through the conduits 13 and 14 past the re-charging valve 35 and through the chamber 15 and conduit 16 to the auxiliary reservoir 2. The control chamber 21- how ever, is cut off from the train pipe 4 and from the auxiliary reservoir 2 by the slide 27 of the valve device 26 the piston 28 of which is subject during the initial period of the release of the brakes to the brake cylinder pressure obtaining in the chamber 29. It will thus be observed that a local surge of eX- cessive pressure in the train pipe will not cause the establishment of a pressure in the control chamber 24 in excess of that desired in the chamber that is to say in excess of the normal train pipe pressure. The fluid under pressure in the chamber 24 and in the chamber 17 in the release valve device 5 with which the control chamber 24 is in communication serves during the release of the brakes as a control spring for the release valve device 5, the brake cylinder and auxiliary reservoir pressures being butted against the control reservoir pressure. The re-charging valve 35 controlling communication between the train pipe 4 and the auxiliary reservoir 2 and the release valve 22 controlling communication between the brake cylinder 3 and the atmosphere are so mounted upon the stem 23 connected to the three diaphragms 19, 20 and 21 of the release valve device 5 that a certain amount of play is permitted between these two valves, the release valve 22 being influenced by a spring 36 for this purpose. Should the aux iliary reservoir pressure rise too suddenly as for instance on account of a local surge of excessive pressure in the train pipe 4 the pressure in this reservoir acting in the chamber 15 on the under side of the diaphragm 20 will close or restrict by means of the recharging valve 35, the communication through conduits 13, 14 and 16 between the train pipe 4 and the auxiliary reservoir 2'and open the release valve 22 controlling communication between the brake cylinder 3 and the atmosphere to a greater extent. If on the other hand the brake cylinder 3 is being vented too rapidly in relation to the rate of re-charging of the auxiliary reservoir 2, the recharging Valve 35 will open a wider communication between the train pipe 4 and the auxiliary reservoir 2, and the release valve 22 will close or restrict communication between the brake cylinder 3 and the atmosphere. It will thus be observed that the rate of re-charging the auxiliary reservoir 2 is dependent upon the pressure obtaining within the latter, the pressure obtaining in the brake cylinder 3 and also upon the pressure obtainingin the control chamber 24 which serves in the release valve device 5 as a spring abutting against the brake cylinder and auxiliary reservoir pressures.

In an alternative constructional embodiment of the invention diagrammatically illustrated in Figure 2 of the drawings instead of the pressure in the control chamber which is charged after the release of the brakes being utilized as a control spring for the release valve device, the pressure obtaining inthe accelerating'bulb' of the triple valve device may be employed for this purpose. V p

Referring now to Figure 2, the accelerating bulb 37 of a triple valve device 1, which bulb is charged with fluid under pressure from the train pipe 4 during an application of the brakes, through a conduit 38 is connected to the chamber 17 between the diaphragms 20 and 21 of the valve device 5 while during release of the brakes the chamber 17 is vented to atmosphere through a conduit 39, a recess 40 in the slide valve 41 of the valve device 26, a conduit 42 and a recess 43 in the slide valve of the triple valve device. Inthis constructional embodiment of the invention the auxiliary reservoir 2 is arranged to be re charged from the train pipe 4, through the valve device 5 on the one hand and also through a conduit 44, a recess 45 in the slide valve 41 of the valve device 26, the piston 28 of which is subject to the pressure in the chamber 29 which is connected to the brake cylinder 3,- through a conduit 46, communication between the train pipe 4 and the auxiliary reservoir 2 being arranged'to be cut ofl' by the slide valve 41 as longas there is a predetermined pressure in the'brake cylin:

der3 so as to prevent the attainment of a pressure higher than that which is desired in the auxiliary reservoir owing to a local surge of excessive pressure in the train pipe. A- non-return Valve 47 is located in the conduit 48 between the recess 45 and auxiliary reser voir 2. The slide valve 41 is also arranged to control communication through passages 38, 39 and 42 from the accelerating bulb 37 ofthe triple valve device 1 and the chamber 17 of the valve device 5to the atmosphere, this communication being cut oil as long as thereis a predetermined pressure obtaining in the brake cylinder 3. The auxiliary reservoir 2 is in this case in constant communica tion through a conduit 49 with the chamber 15 between the diaphragms 19 and 20 of the valve device 5 and is arranged to be recharged from the train pipe 4 through a conduit 50, past the re-charging valve 35through the chamber 15 and conduit49, the rate of recharging being controlled by the re-charging valve 35 which is controlled by the diaphragms. 1 a

The operation of the embodiment of the invention described above with reference to Figure 2 is similar to that ofthe embodiment described withreference to Figure 1 but in this case the rate-of re-charging of the aux iliary reservoir 2 is dependent upon the pressure obtaining within the accelerating bulb (Figure 2) of the triple valve device 1 and also the pressure obtaining within the brake cylinder 3 at any time during. the application or release of the brakes instead of upon the pressure obtaining within the control chamber 24 (Figure 1) and the pressure obtaining within the brake cylinder 3.

' It will be observed that in the alternative constructionalembodiment of the invention the auxiliary reservoir 2 and the chamber 17 of the. release valve device cannot be overcharged with fiuid under pressure owing to .a

surge of excessive pressure in the train pipe 4 during the release of the brakes,as during the release ofthe brakes the chamber 17 and the auxiliary reservoir 2 are both cut oil from the train pipe 4, and should the pressure in the auxiliary reservoir 2 rise too rapidly by flow through the valve device 5, then the latter will cut'oii' or restrict this flow automatically as described withreference to Figure' 1 of the drawings.

Referring now to Figure 3, the train pipe of the braking system is in communication with a-chamber 51 on one side of the controlling or triple valve piston 52 through a port 53 and in the release position of the piston 52 is also incommunication with a chamber 54 on the otherside of the piston'52 through a groove 55. The chamber 54'is connected through a conduit'56, a port 57 in a piston valve 58 of a valve device 59 and a conduit 60 with a control chamber 61 which is also connected through a conduit 62 and a cali- 1 brated orifice 63 to a chamber 64 inside a valve seat 65 of the triple or controlling valve device.

The valve device 59 comprises a piston 66 subject in chamber 67 to the pressure in the brake cylinder of the apparatus which is directly connected to the chamber 67 through a conduit 68. The piston 66 is subject to the action of a spring 69 and acts through its piston valve stem 58 and a spring 70 on a piston 71 connected to avalve piston 72 adapted to control communication between a chamber 73 on the top of the piston valve 7 2 and a conduit 7 t which is connected indirect ly (preferably through the triple or controlling valve device) with the brake cylinder of the apparatus. The chamber 7 3 contains a spring 75 acting upon the piston valve 72 and is connected directly to the auxiliary reservoir of the apparatus through a conduit 76. Seats 77, 78 and 7 9 adapted to cooperate respectively with cooperating valve members 80, 81 and 82 respectively are provided in order to prevent leakage of fluid past the various joints in the valve device 59.

In the release position, the various parts of the apparatus are in the positions in which they are illustrated in the drawings, and communication between the train pipe and the control chamber 61 through the conduit 53, the. groove 55 and conduit 62 is cut off at the valve seat 65. Communication between the train pipe and the control chamber 61 is, however, established through the conduit 53, the groove 55, the chamber 54:, the conduit 56, the port 57 in the valve piston 58, and the conduit 60, the piston valve 58 and the piston 66 being maintained in their lowest position by the auxiliary reservoir pressure acting in the chamber 73 above the piston 7 2, the brake cylinder pressure acting in the chamber 67 being substantially equal to atmospheric pressure.

Vhen the train pipe pressure is reduced in order to effect an application of the brakes, the triple or controlling valve piston 52 is moved upwards by the pressure obtaining in the chamber 54: and as soon as the piston 64: leaves the seat 65, the pressure obtaining in the control chamber 61 also acts in the chamber 54. Communication between the train pipe and the chamber 54: through the groove 55 is cut off in this application position of the piston 52 and fluid under pressure is supplied through the triple or controlling valve device to the brake cylinder to apply the brakes. As soon as the brake cylinder pressure attains a predetermined value (e. g. 0.50 kg.) the piston 66 is raised owing to this pressure acting in the chamber 67 and communication between the chamber 54 in the triple or controlling valve device and the control chamber 61 is cut off by the valve piston 58, and the valve piston 7 2 outs oflf communication between the auxiliary reservoir and the brake cylinder through the chamber 73 and the conduit 7 4:.

If the train pipe pressure is now raised in order to release the brakes the piston 52 upon the train pipe pressure attaining a predetermined value (e. g. 5 kg.) descends and cuts ofl communication between the train pipe and the control chamber 61 through the conduit 62 and as the valve piston 58 remains in its upper position until the brake cylinder pressure has been reduced to a predetermined value (e. g. 0.50 kg.) by flow of fluid from the brake cylinder to the atmosphere through the triple or controlling valve device, communication between the train pipe and the control chamber 61 through conduits 56 and 60 is also cut off by the piston valve 58.

There is therefore no danger of the pressure in the control chamber 61 rising above a predetermined value (e. g. normal train pipe pressure) by flow of fluid from the train pipe even if the train pipe pressure is raised temporarily above its normal value in order to effect a rapid release of the brakes, as there is no communication between the train pipe and the control chamber 61 during the release of the brakes until the brake cylinder pressure acting in the chamber 67 has decreased to a predetermined low value (e. g. 0.50 kg.) and permitted the piston valve 58 to descend under the action of the spring 73 and auxiliary reservoir pressure acting in the chamber 75.

It will be understood that the invention may be put into practice in a variety of ways and, although two preferred constructional embodiments of the invention have been described by way of example, the invention is not in any way limited to such embodi ments which may be varied as desired to suit particular requirements without exceeding the scope of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. Fluid pressure braking apparatus comprising a controlling valve device influenced by the pressure in a chamber, in which the chamber is in communication with the train pipe during application of the brakes through 1 two conduits until the brake cylinder pressure attains a predetermined value whereupon one of these communications is cut off, the other communication being also cut off when the train pipe pressure attains a pre- 1 determined. pressure during release.

2. In a fluid pressure brake, the combination with a brake pipe and brake cylinder, of a valve device subject to the opposing pressures of a controlling chamber and the brake pipe for controlling the brakes and a valve device influenced by the pressures in the controlling chamber and the brake cylinder for controlling the charging of said chamber 1 from the brake pipe. v

3. In a fluid pressure brake, the combina tion with a brake pipe and brake cylinder, of a valve device subject to the opposing pressures of a controlling chamber and the brake pipe for controlling the brakes and a valve device influenced by the pressures in the controlling chamber and the brake cylinder for controlling the supply of fluid from the brake pipe to said chamber.

chamber is charged with fluid under pressure, means for charging said regulating chamber from the brake plpe, and means op- ALFRED CHEVILLOT.

4. In a fluid pressure brake, the combination with a brake pipe and brake cylinder, of a valve device subject to the opposing pressures of a controlling chamber and the brake pipe for controlling the brakes and a valve device subject to the pressures of the controlling chamber and a regulating chamber charged with fluid from the brake pipe for controlling communication through which the controlling chamber is charged with fluid under pressure from the brake pipe.

5. In a fluid pressure brake, the combination with a brake pipe and brake cylinder, of a valve device subject to the opposing pressures of a controlling chamber and the brake pipe for controlling the brakes, a. valve device subject to the pressures of the controlling chamber, and a regulating chamber charged with fluid from the brake pipe and the brake cylinder for controlling the rate of charging of the controlling chamber from the brake 1 e. p In a fluid pressure brake, the combination with a brake pipe, auxiliary reservoir, and brake cylinder, of a triple valve device subject to the opposing pressures of the auxiliary reservoir and brake pipe and operated upon a reduction in brake pipe pressure for supplying fluid from the auxiliary reservoir to the brake cylinder and a valve device subject to theopposing pressures of the brake cylinder and a regulating chamber for controlling communication through which the auxiliary reservoir is charged from the brake P In a fluid pressure brake, the combination with a brake pipe, auxiliary reservoir, and brake cylinder, of a triple valve device subject to the opposing pressures of the auxil- V iary reservoir and brake pipe and operated upon a reduction in brake pipe pressure for supplying fluid from the auxiliary reservoir to the brake cylinder and a valve device subject to the opposing pressures of the brake cylinder and a regulating chamber for controlling communication through which said triple valve device releases fluid from the brake cylinder.

8. In a fluid pressure brake, the combination with a brake pipe and brake cylinder, of a valve device subject to the opposing pressures of a controlling chamber and the brake pipe for controlling the brakes, and a valve device influenced by the pressure in a regulating chamber for controlling communication through which said controlling

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