US1595755A - Pneumatic control apparatus - Google Patents

Description

Aug- :10 1926.- 1,595,755

R. BROOKS ET AL PNEUMATIC CONTROL APPARATUS Filed July 13, 1922 Fig.1 9

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1 Z4 1 2'7 5 so 15 WITNESSES: INVENTORS ATTORNEY Patented Aug. 10, 192, 3,

PAT EM 3 te M ansissteps elem t reis u s er emimm LaNn, AssIeNons o wnsrmenousn ELECTRIC AND MANUFACTUBING'CQMPAZHNYI,

i nnuiv mprc CONTROL APrARnTUs. 7

Application filed July 13, 1922, Serial- No.

Gui: invention relates to 'apparatus for controlling the raising and lowering 'ot the trolley in systems of electric'traction with overhead conductors and in particular tov systems of this nature in which a number of- 'trol'leys are to be simultaneously"operated throughoutan electrictrain. 1

For this purpose, it is usual to provide. devices operated by means of compressed air the supply of which is controlled'by' electricall-yoperated valves located in thetrolley ears or locomotives and'control'led by a suitable arrangement of master switches and train lines. Where the current for operating the master switches is obtained from an auxiliary motor generator, which is driven by current suppliedfrom the main supply conductors or trolley wires, a plainsolenoim. operated valve wilil give rise to trouble in the eveutof either a breakdown of the auxiliary generator or drop" in the potential of, the main conductors as, under these circumstances, the trolleys will be automatically lowered and thus prevent any current beingsupplied from the main conductors;

One ofythe objects of'our invention is to provide means for so controlling the supply of compressed air'tothe trolley raising and lowering apparatus that, when the controlling; devices are moved into either the raised or lowered positions, they will remain in the position to which they were.

last moved; until positively moved to the other position;

. Anotherobject of ourinvention is to sim plify and improve generally, the construction and'operation of fluid-actuated devices.

To enable the invention to be clearly .un. dersto'od, it will now be described with reference to the accompanying drawings, ,lIl which i o Fig. 1 is a view, insectional elevatiomof the apparatus ,whi'chI employ for governing the supply ofrcompressed air to the operat-? ing cylinderiof atroll'ey, and o I Fig; 2 is an electricaldiagram of control circuits for operating thevalve device shown in Fig:1.- j

The valve device: comprises a suitable casing 1 containing the inlet port'2 connected m supply of compre'ssed air (not shownand a port connected-by a-pipez-with the Gj l1IIC1QI 'WlI1QlI oonta instlie usual piston that raises the" trolley through suitable iiuk may be actuated 574,721, and in England July is, 1921..

and lever connections (also not shown). Vithin the casing 1 is disposed an inlet valve): having a webbed stem 5 extending through the valve seat- 6 with which it"cooperates. The "valve 4 operates Within an inlet pocket? in the casing 1 and is normal-' ly pressed upon the seat 6'by means of a spring" 8 I screwed into the end of the casing 1accord'-' ing towell known practice.

' [in exhaust'valye 10 is also located within thev casing'l, in axial alinement with the in let valve; 4: and is provided'with. webbed stem 11 extending through the seat 12' with which said valve cooperates;

The stems 5v and 11 of the inlet and exhaust valves, re spectively, are'of such length'that, when the exhaust valve is closed its stem engages the stemgof the inlet valve andopens :thelatter to the full extent'so i-a-sito adimit air-to the trolley operating cylinder. "On' the other hand, when the inlet valve 4 is closed the exhaust valve '10 is "fully opened to permit the air in the trolley-operating cylinder to escape through an exhaust; port 18 in the back ofthe' casing 1; 1 In axial alinement with the inlet and exhaust'valves,"is arranged a piston 14 that operates 'in a cylinder 'lfi in the lower. part of the casing 1. The piston 14 is provided with an upwardly extending ste'mlfith'at engages the' underside of the exhaust valve 10. A compression spring 17 is arranged on the upper side of the piston 14 so that the latter is normally biased to its lower position. 7' Attached to the lower end of the casing-'1 is, a casting 18 containing the electro-phew matic mechanism for admitting compressed air to, and releasing it'from beneath' the piston 14:. nism comprises an admission Valve 19 no1 mally closed upon a seat 20 by means of a spring QLQAs' will be observed, the. valve; 19 h to control communication between a pipe 23, which leads to "a source. of supp y and a pasSageQQ-provided in the casting 18. Th Pa ag -2 c m unicates with rea sage 2 th oug cheek Ya1ve2 tha s nan m 'llY'rPF SS Q: ige llet$ 5593 ?i by eri s 21 The assa fi ees m eieetss with the pa 2 b eath th 9 m 1 -5 The-Pa fitted within a recessed "cap 9 Such elGtlQ-pileumatic jmecha of compressed air (not-shown),

have communication through a passage 30 with a chamber 31 that contains a valve 32 which is normally pressed by a spring upon a seat 34, the valve 32, when opened, placing the passage 30 in communication with an exhaust port 35.

The admission valve 19 and the exhaust valve 32 are operated electro-magnetically, one of the electromagnetic mechanisms being shown in section, at the righthand side of Fig. 1, by way 01: example. Said mechanism comprises a coil 36 having suitabl terminals 37 and wound upon a tubular iron core 38 through which passes a pin 39 which rests upon the upper end of the stem of they valve 32. The pin 39 extends above the up per end of the core 33 and an armature 4" rests upon the upper end of the pin 39.

Upon energization of the coil 36, the armature 40 is attracted by the core 38 so that the pin 39 is biased downwardly and, engaging the valve 32, opens the latter, thereby placing the space 29 beneath the piston 14- in communication with the exhaust port 35. An external button 41, extending through a casing 42 which covers the electromagnetic mechanism, is provided to enable the valve 32 to be manually opened.

The admission valve 19 is operated in an exactly similar manner but, in addition, the valve operating pin 43 is itself provided with a valve face 44 adapted to engage a seat 45 when the coil 36a is energized, that is to say, while the admission valve 19 is normally closed by means of the spring 21, the auxiliary valve 44 is normally open to place the passage 24 in communication with an exhaust port 46;

A by-pass for compensating for loss of pressure in the chamber 29 is indicated at 47 and is conveniently provided in the wall of the casing 1, to place the space above the exhaust valve 10 in communication with the space 29. A screw pin 43 is provided for adjusting the sectional area of the by-pass 47, for the purpose of regulating the relative pressure upon the two sides of the piston 14.

The operation of the valve device is as follows: When it is desired to raise the trol ley into contact with the trolley conductor, the coil 36a is energized by the closure of a suitable switch or the button 41 may be depressed by hand, so that compressed air from the pipe 23 is admitted through the valve 19 to the passage 24 which is now out off from the exhaust port 46 by closure of the auxiliaryvalve 44. The compressed air traverses the passage 24 and passes the check valve 26 and traverses the passage 25 into the chamber 29, to force the piston 14 upwardly, the exhaust valve 32 being at this time closed. The piston thus closes the exhaust valve 10, and the stem 11 of this valve engages 131165139125 ot-the normally closed inlet valve 4 and opens the latter to admit compressed air through the port 2 from the supply to the port 3 connected with the cylinder which operates the trolley whereby the latter is raised.-

The inlet valve 19 may be then permitted to close. lVhen this occurs, the valve 44 exhausts the passage 24 but the pressure is retained within the chamber 29 behind the piston 14 by reason of the non-return valve 26, Compressed air is admitted from the space above the exhaust valve 10 through the bypass 47, thereby compensating for any leakage of pressure past the piston 14 or elsewhere in the auxiliary pneumatic control system. It will thus be seen that, when the trolley has been raised, it will bemaintained in its elevated position, irrespective of any electrical circuits which may fail.

In order to lower the trolley, the right hand coil 36 is energized, or the button 41 depressed, so that the valve 32 is opened to exhaust the pressure behind the piston 14 to atmosphere through the passage 30 and exhaust port 35. The piston 14 is then forced downwardly by pressure upon the valve 10, assisted by the spring 17. The exhaust port 35 is of relatively larger area than the effective area ofthe by-pass 47.

Upon the piston 14 moving down, the inlet valve 4 is closed to cut off the pressure from the supply connected to the port 2 and, at the same time, the air in the operating cylinder of the trolley is exhausted through the port 3, the valve 10 and the exhaust port 13 to atmosphere. This having occurred and the inlet valve 4 being closed, no pressure can be supplied beneath the piston 14 by the by-pass 47. The coil 36 may then be de-energized to permit the valve 32 to close in readiness for a ain. operating the device for raising the trolley. The extent of the by-pass is regulated by an adjusting screw 48, which is necessary, since, if the opening be too large, the opening of the chamber 29 to exhaust through the valve 32 may not result in a sufiicient reduction of pressure below the piston 14 to eifect the proper opening of the exhaust valve 10. On the other hand, if the by-pass opening is too small and the piston 14 is somewhat worn or leaky, the valve 10 would tend ,to open to the exhaust instead of remaining properly closed. The spring 17 is provided to insure that the valve 10 and also the piston 14 will always return to the exhaust position when the pressure within the space 29 is released.

In trains where a number of trolleys are to be simultaneously operated, the electromagnet coils 3636a of the several trolleys may be energized from circuits extending throughout the length of the train. Referring to Fig, 2, wherein two valve e ate s awards-we w he i ee iaa are lowering coils 36(L36' is connected to the conductor 51 while the other ends of the said coils are respectively connected to the selection conductors 52 and 53.

In each motormans compartment of the train is disposed a two-way switch 54, the blade of which is connected to the positive -1nain train bus 50. The switch 5a normally occupies its oii position, being thus biased by means of a spring or otherwise i, and it may be moved by hand into engagement with either of the contact members 55 or 56, to efl ect the connection of the trolley raising and lowering coils 36a-36 to the main bus conductors 51. With this arrangement, the operation of any one of the switches L will raise Or lower all the trolleys of the train.

In the event of the auxiliary electric supply being inoperative for any reason, such as when no trolley is elevated and in contact with the trolley wire, the raising of all the trolleys may be effected "by pressing the left-hand button 41 of anyone of the valve devices In this manner, compressed air is admitted to that valve device, the button of which has been depressed so that the trolley of that particular device is raised and thereby establishes the auxiliary supply which will then permit the remaining trolleys, if any, to be raised by the operation of any one of the switches 54:.

It will be understood that various modi lications may be made in the construction of the valve devices and in the arrangement of the control circuits therefor, without departing from the scope of the invention. 1

W e claim as our invention: I 1. In combination, a chamber having an inlet opening and an outlet opening, valves for controlling said openings, said valves being adapted to close one opening when they open the other, a piston for operating the valves, a cylinder in which the piston is slidably mounted, means for supplying fluid pressure to the piston to efl'fect its operation in ing, a by-pass for connecting the chamber with the cylinder to equalize the pressure in the cylinder and chamber to maintain the piston in a predetermined position 2. In C0l'Ilb1Il&l?lOI1,-3. chamber having an inlet opening and an outlet opening, valves {or controlling said openings, said valves one direction to close the exhaust openbeing adapted to close one opening when they open the other, a piston for operating the valves, a cylinder in which the piston is slidably mounted, means for supplying fluid pressure to the piston'to eflect its operation in one direction to close the exhaust open- 1 ing, a bypass for connecting'the chamber with the cylinder to equalize the pressure in the cylinder and chamber to maintain the piston in a predetermined position and means for controlling the flow of fluid through the by-pass. 8. In combination, a chamber having an inlet opening and an outlet opening, valves for controlling said openings, said valves being adapted to close one opening when they open the other, a pistonfor operating the valves, a cylinder in which the piston is slidably mounted, means for supplying fluid pressure to the piston to effect its operation exhaust opening, a bypass for connecting the chamber with the cylinder to equalize the pressurein the cylinder and chamber to maintain the piston in a predetermined position, means disposed for independent operation to release the pressure on the piston and means energized by the movement of the piston under the influence of fluid inopen position.

5. The combination with a fluid pressure chamber, of a valve for controlling the admission of fluid thereto, an exhaust valve therefor, fluid pressure operated means for normally maintaining the valves in open and closedpositions respectively, and means for utilizing pressure from the said chamber to assist in maintaining the said valves in their normal positions,

In testimony whereof, we have hereunto subscribed our names this 23rd day of June, 1922. I

ROBERT BROOKS. ALAN PRIESTLEY.

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