US1556590A - Pneumatic power control - Google Patents

Description

J. T. COWLEY PNEUMATIC POWER CONTROL Filed g y 1925' 2 Sheets-Sheet 1 Patented Oct. 13, 1925.

UNITED STATES PATENT OFFICE.

JAMES '1, COWLEY, OE SYRACUSE, NEW- YORK, ASSIGNOBT-O THE LAMSON COMPANY, OF SYRACUSE, NEW YORK, A CORPORATION. OF MASSACHUSETTS.

PNEUMTIC POWER. CONTROL.

Application filed July 12, 1923. Serial No. 651,064.

To all whom it may concern:

Be it known that I, J AMES T. COWLEY, a citizen of the United States of- America, and resident of Syracuse, in, the county of Onondaga and State of New York, have invented new and useful Improvements in Pneumatic Power Controls, of which the following is a specification.

This invention relates to power control apparatus for pneumatic despatch systems of the general type. ofthat disclosed in the patent to Libby, 968,576, August 30, 1910 and comprising a main valve operated by a diaphragm which moves inaccordance with pressure variations in the transmission line.

Principal objects of'the present invention are to provide a controlling apparatus of the above type which is verysensiti've both to the slight decrease in pressure in the transmission line occasioned by the introduction of a carrier and to the slight increase'in pressure-in the line resulting from discharge of a carrier; to provide such an apparatus having means for closing the main valve 7 quickly upon such slight decrease in pressure incident to the delivery of a carrier or optionally to permit it to close more slowly and in accordance witha timing device and irrespective of the discharge of. a carrier from the transmission line, but so designed that the valve will-not flutter; or chatter under rapid pressure variations; and to pro vide controlling means for the main valve operating diaphragm which imposes substantially no load upon said diaphragm so that the latter may be sensitively responsive to slight pressure variations and capable of moving the valve quickly and reliably.

In the accompanyingdrawing a preferred embodiment of the invention is illustrated by way of example and in such drawings:

Fig. 1 is a side elevation, partly in vertical section and partly diagrammatic, illustrating a controlling apparatus embodying 7 the present invention;

Fig. 2 is a cross section on the line 22 of Fig. 1, certain parts being indicated diagrammatically and Fig. 3 is a fragmentary vertical section through theright hand portion of the de vice shown in Fig. 1 illustrating details of construction.

Referring to the drawings, the power controlling apparatus is shown as comprising 5 a housing consisting of the lower part 1 and the upper. part or cover 2. The lower part 1 is provided with an outlet cavity 3 which is connected by means of a pipe 4 with the usual vacuum drum (not shown) of such a system.

A casing 5 projects intothe outlet cavity 3, such casing preferably being integral with the wall of the lower partofthe housing. This casing is hollow, furnishing an inlet cavity 6 which communicates by means of a pipe 7 with a transmission line of the system. Preferably the controlling apparatus is arranged at the central station ofsuch a sys tem and is connectedto the transmission line at a point adjacent to thedelivery terminal of such transmission line.

The upper and lower walls 8 9' respectively of the casing 5 are provided with openings for the reception of the heads 10, 11 of a balanced piston valve 12. The lower head of'this valve is preferably provided with a small passage 13'connecting the chambers 6 and 3 whenthe valve is closed. The upper head 10 of the valve hasa-stem 1 1 which slides in a suitable opening in a boss 15 projecting from the upper wall 16' of the member '1 ofthe housing.

This upper wall extends outwardly in the form of a substantially radial flange-which terminates in a circumferential'seat 17. The outer edges ofa flexible diaphragm 18 are secured to the seat 17 by means-of'a flange member 19 forming apart of the cover 2. The central part ofthis diaphragm is clamped between two plates 20, 21 respectively which are secured totheupper end of the stem 14 by means of a nut 22.

The diaphragm 18 thusdivides'the upper part of the housing into upper and lower chambers 23, 24 respectively.

The upper chamber 23 of the housing is connected to the outlet cavity 3 by means of a passage 25 preferably extending through a boss 26 outstanding from the housing. The diaphragm is provided with an opening at 27 where it crosses the passage 25 in order that the passage may not be interrupted at this point.

The lower chamber 24iis provided with a passage 28 within a boss 29: outstanding from the side wall ofthe housing, and this passage terminates in aport 30 opening to the atmosphere. This port is surrounded by a suitable valve seat with which a valve 31 engages for closing the port. This valve is Ill) rovided with a stem 32 which neferably orms the core of a solenoid 33. 'I he weight 0f the valve 31 with its stem is ordinarily siiflicient to hold it normally against its seat although a spring may be provided for seating it if desired.

A passage 34 (Fig. 3), extends through a boss 35 arranged at a suitable point on the flanged portion of the housing and connects the chambers .23 and 24. This passage is controlled by a needle valve 36 which may be set so as to provide for the pass e of air at any desired rate fromone of the c ambers to the other.

A slidable pastor stem 37 is arranged coaxially with the stem 14 of the main valve 12 find is guided for vertical movement by passmg through a bore in a threaded sleeve 38 mounted in an opening at the central part of the cover .2. A spring 39 encircles the stem 37 and bears at its upper end, against the inner surface, of the sleeve 38'. Its other end rests upon a nut 40 secured to the lower end of the stem 37. This spring is normall under tension and tends to move the stem 3 downwardly so as to cause it topress upon the upper end of the stem 14, thus holding the diaphragm 18 and the main valve 12 in the posltion shown in F i 2.

An auxiliary or contro motor 41 is mounted upon the cover member 2. This auxiliary motor preferably comprises a housing, one part of whichfis integral with the cover, and which eomprisesthe upper and lower cham- 7 bers 42,43 respectivel separated by the flexible diaphragm 44. he lowerchamber 43 communicates with the atmosphere by means of a small port 45 while the upper chamber communicates with the transmission line of the system by means of a pipe 46.

The diaphr 44 is furnished with a stem 47 encirc ed by a spring 48. This spring is of'just suificient stiffness to hold the diaphragm in substantially horizontal position agalnst the pressure of the atmosphere in the lower chamber 43 when conditions in the transmission line are normal and no carrier is passing but to permit the diaphragm to bulge upwardly upon the slight decrease in pressure in the transmission line incident to the introduction of a carrier therein. The upper end of the stem 47 underlies the lowermost of a pair of resilient contact fingers 48, 49 respectively secured to an insulating block 50. These fingers are provided with opposed contacts which are normally separated from each other but which may be caused to contact by upward movement of the stem 47.

A conducting wire 51 extends from the resilient finger 49 to one terminal of the solenoid 33. Preferably a battery 52 or other source of electrical energy is interposed in this wire. The other resilient finger 48 is connected by means of a wire 53 to a resilient fi r .54 mounted"- on an, insulating block A second resilient fin r 56 is mounted upon an insulating bloc 57 and normally engages the finger 54. Preferably these fingers are inclined -11 their supporting blocks to t eir points of engagement as indicated in Fig. 2. A conducting wire 58 leads from the finger 56 to the other terminal 'of the solenoid.

A circuit breaker 59 is arranged immediately beneath the point of contact of the fingers 54 and56. This circuit breaker is a tapering plug or wedge of insulating In terial carried by the upper end of a slide member 66 arranged to reciprocate m a lo 61 formed in'a boss 62 carried by the coverfl, A spring 63 is secured to the outer c of the boss and bearsagainst the side of the slide member seas frictionally to retain the latter in any position which i may'p, a?

r fir 3' I v The slide memher 60,15 fiui mshedwith axially elongate slot or recess 64 in its side and: a finger or lug 65 carried y t e up r .1 end of the stem or post 37 projects intotfis .0

recess. y

A second auxiliary or control motor 661,5; also carried'by the cover 2 (Fig. 1). This second auxiliary motor is of the same construction as that 41, comprising the upper and. lower chambers 67, 68 respectively separated by the flexible diaphragm 69. .The lower chamber 68 commim ce es' w the l here by pper means of a small port 70, while. chamber is connected line by means oi a pipe, 71. 3 r I The diaphragm 69 s proyided wi h a, 72 encircled by1a s ring 73]., This 5pm (18 somewhat heavier an the spring 48 of motor 41 so that the diaphragm 69 is net moved to anysubstantial extent when a can riege is first introduced into the tra tu The upper end of the stem 72 underlies the The operation of the device is euhstmtially as follows, it being assumed that the parts are in the position shown in 1 and 2, that no carrier is in the transmission line and that the needle valve 36 has been so set as to of air from the ciia mber 24 of the housing to the chamber 23. When the parts are thus positioned a slight flow of air is maintained in the transmission tube, being drawn through the passage 13 in the lower ardly from N submtially of the motor to the on a m The u per finger 75 is connected rmit a rapid movement 3 head 11 of the main valve. This lowers the. pressure in the transmission tube somewhatbelow atmospheric pressure and this low pressure is also maintained in the chambers 42 and 67 of the auxiliary motors 41 and 66 respectively. The. upper chamber 23 of the housing being in direct communication with the outlet chamber 3, is also under low pressure, substantially lower than that of the auxiliary motors.

en a carrier is introduced into the transmission line its resistance to movement results in a further decrease in pressure in the transmission line. This immediately causes the diphragm 44 of the auxiliary motor 41 to rise, thus completing an electrical circuit through the contacts carried by the fingers 48 and 49. This circuit includes the wire 51, the battery or other source of energy 52, the, solenoid 33, the wire 58, the resilient lingers 56, 54, and the wire 53. Immediately upon completing this circuit, the solenoid 33 is energized, lifting the valve 31 and admitting atmospheric pressure beneath the diaphragm 18. The latter rises very quickly, thus opening the main valve 12 and admitting a rush of air from the transmission line through the outlet passage 3 to the vacuum drum. This sudden rush of air lowers the pressure in the transmission line to a. very marked degree, thus rapidly moving the carrier toward its destination and decreasing the pressure in the auxiliary motor 66, suificiently to raise the dia hragm 69 and close the contacts carrie by the members 74 and 75. This completes an electrical circuit through the wire 78, the wire 58, the solenoid 33, the wire 51, the battery 52, the contact fingers 49 and 48 which are still in engagement, the wire 53, and the wire 77.

As the main valve approaches its upper limit of movement the lug comes into contact with the upper end wall of the recess 64, thus raisin the slide member 60 and thrusting the pfiig 59 between the contact fingers 54, 56. This immediately breaks the circuit first described through these fingers and would result, were it not for the closure of the circuit between the fingers 74 and 75, in deenergizing the solenoid 53 and closing the valve 31. However, as the circuit is complete at this time through the fingers 74 and 7 5, the solenoid remains active and the valve 31 is kept open.

lVhen the carrier is delivered from the transmission line and the pressure in the latter drops slightly, the spring 73 of the auxiliary motor 66 returns the stem 72 to normal position, thus braking the circuit between the fingers 74 and 75, deenergizing the solenoid, and permitting valve 31 to close.

As soon as the valve 31 is closed the spring 39 begins to act to depress the diaphragm 18, this action being controlled by the rate at which the air in the chun'iber 24 is able to escape from the passage 34 into the chamber 23. As above stated, the needle valve 36 is so set as to permit a rapid move ment of the air from the chamber 24 so that the main valve 12 is rapidly returned to its seat, thus stopping the flow in the transmission line. As the diaphragm 18 approaches the lower limit of its movement, the lug 65 engages the lower wall of the recess 64 and restores the slide 60 to normal position, pern'iitting the fingers 54, 56 to come into contact. As the pressure in the transmission line is now restored to normal the diaphragm 44 reassumes. the position shown in Fig. 2, breaking the contact between the fingers 48 and 49 and restoring the system to normal condition.

The controlling valve 31 of the main valve actuating motor is very sensitively controlled by the slight decrease in pressure in the transmission line incident to the introduction of a carrier, but the main valve may be restored to normal position by the slight increase in the pressure in the transmission line incident to the delivery of a carrier, although at such time the pressure in the transmission line is far below that necessary initially to open said valve. The device thus operates independently of any predetermined timing action to open the main valve upon the introduction of a carrier into the transmission line and to close the main valve quickly after the discharge of the last carrier therefrom. The carriers are thus moved to their destination with certainty and all danger of premature stoppage of the air supply before the last. carrier has been discharged is eliminated.

\Vhile the complete device as above described is preferred, it is possible, by eliminating the second auxiliary motor 66 with its associated parts, to employ the controlling device to advantage when it. is desired to have the main valve close a predetermined interval after its opening.

If the second auxiliary motor 66 be eliminated, the rising of the diaphragm 18 causes 3 the circuit breaker 59 to break the circuit between the fingers 54 and 56 in the manner above described, but in this case, the solenoid 33 is immediately deenergized and the controlling valve 31 is closed. By'setting the needle valve 36 at the proper point, the return of the diaphragm 18 to its normal position, and the closing of the main valve may be caused to take place after almost any desired predetermined interval regardless of the presence or absence of a carrier in the transmission line. If under such circumstances the main valve should be closed prior to the delivery of the last carrier, the continuedlow pressure in the transmissiol'i line will again actuate the auxiliary motor 41, thus reenergizing the solenoid and causing the main diaphragm 18 with the valve 12 to rise, thus again breaking the circuit and closing a repetition of the cycle of movement.

The apparatus described is of relatively simple construction, reliable in operation, and is very effective in conserving the air supply and preventing waste of power in the transmission system.

I claim:

1. Power control apparatus for pneumatic dispatch systems comprising a main valve, a motor for operating it, means operative upon the occurrence of a slight decrease in pressure in the system to initiate operation of the motor to open the valve, and independent means operative upon a slight subsequent increase in pressure in the system for initiating operation of the motor to close the valve. 7

2. Power control apparatus for a pneu matic dispatch system having a transmission line, comprising a main valve,"a pneumatic motor for opening and closing the valve, a controlling valve for the motor, means for actuating the controlling valve to initiate operation'of the motor to open the main valve upon the decrease in pressure in the transmission line incident to the introduction of a carrier therein, and independent means for initiating closing of the main valve upon increase in pressure in the transmission line due to delivery of a carrier from the latter.

3. Power control apparatus for pneumatic dispatch systems comprising a pneumatic motor, a valve for controlling its operation, electro-magnetic means for actuating the valve, an auxiliary, pressure controlled motor, a circuit closer operable thereby to close an electrical circuit through said electromagnetic means, and a circuit breaker actuable by the pneumatic motor to break the circuit through the electro-magnetic means.

4. Power control apparatus for pneumatic dispatch systems comprising a pneumatic motor having a diaphragm, a valve for controlling admission of power fluid to one side of the diaphragm, electrical means for actuating the valve, an auxiliary, pressure controlled motor for completing the electrical circuit through the valve actuating means, and a slide member actuable by the diaphragm and provided with a circuit breaker for opening the circuit through said valve actuating means.

5. Power control apparatus for pneumatic dispatch systems comprising a pneumatic motor having a diaphragm exposed on one side to reduced pressure, a valve for controlling admission of atmospheric air to the other side of the diaphragm, an electro-magnetic device for opening the valve,an auxiliary motor operating under decreased pressure in the system to complete the circuit through the electro-magnetic means, a sliding post movable by the diaphragm upon the opening of said valve, and a circuitbreaker carried by the post and operableito break :the circuit through said electromagnetic, device as the diaphragm completes its movement;

6. Power control apparatus for a pneumatic dispatch system having a pneumatic motor comprising a housing having chambers separated by a movable wall, one of said chambers communicating with a low pressure space, a valve controlling admission of power fluid to the other chamber, a solenoid for actuating the valve, an auxiliary pneumatic motor having an element subject to fluctuations in pressure in the system- I. circuit closer connected to said element :ior completing an electrical circuit through the solenoid, a slidable stem resting upon the diaphragm and movable thereby, and moircuit breaker carried by the stem: for breaking the circuitthrough the solenoid as like diaphragm approaches the'limit ocf its'momment in one direction. i i 1: H

7. Power control apparatus for pneumatic dispatch systems comprising a mamvalve, a pneumatic motor for operating it, anormally closed controlling .valve for the motor, means operable by a slight decrease in' ressure in the system to open the centre ling valve, means operable as the main valve approaches the limit of its opening movement to permit the controlling valve to close, and 190 other means for holding the controlling valve open until the pressure in the system has increased. a

8. Power control apparatus for apneumatic dispatch system having a transmi sion tube, comprising a main valve, a pneumatic motor for actuating said; main vatve and a pair of pneumatic motors for eontrollin the operation of the first named motor, eac of said pneumatic control m'otors having 1 a spring pressed diaphragm exposed to the air pressure in the system and movable under fluctuations in such pressure induced by the introduction into or discharge of carriers from the transmission tube, one of said diaphragms being subject to greater spring pressure than the other. p l 1 9. Power cont 1 apparatusfor pneumatic dispatch systems comprising a main valve actuating motor and a pair of auxiliary motors for controlling said main valve motor, each of said auxiliary motors normally operating in accordance with variations 1n pressure in-the system, connections between the respective control motors and the main valve motor, and means actuated by the main valve motor for rendering the connections to one of the auxiliary motors temporarily inoperative.

10. Power control apparatus for a pneuto fluctuation in pressure in the line, one of said penumatic motors being constructed and arranged to initiate valve opemng .znove- 'ment of 'the first named motor when a car rier is introduced into the line, the second pneumatic motor being constructed and arranged to initiate valve closing movement of the first named motor upon discharge of a carrier from the line.

11. Power control apparatus for a pneumatic dispatch system, having a transmission line, comprising a main valve for de termining the air flow in said line, a motor for actuating the valve, and a pair of auxiliary motors for controlling said first motor, said auxiliary motors operating in accordance with pressure variations in the transmission line induced by the introduction into or discharge of carriers from said line, one of said auxlilary motors being more sensitively responsive to slight pressure decrease in the system than the other.

12. Power control apparatus for pneumatic dispatch system comprising a main valve, a pneumatic motor for operating it, a controlling valve for the motor, an electromagnetic device for moving said controlling valve, a pair of auxiliary pneumatic motors each having a diaphragm movable by pressure variations in the system, independent circuit closers connected to the diaphragms of the respective motors for closing circuits through said electro-magnetic device, and means actuated by the main motor for interrupting the circuit closed by one of the auxiliary motors.

13. Power control apparatus for pneumatic dispatch systems comprising a main valve, a pneumatic motor for operating it, a controlling valve for the motor, a pair of auxiliary motors each having a part movable in accordance with pressure fluctuations in the system, connections operable by the moving part of one of said motors for causing the controlling valve to open, means actuable as the main valve approaches fully open position to render said connection inoperative, and means operable by the mov ing part of the other auxiliary motor to prevent the closing of the controlling valve.

14. Power control apparatus for pneumatic dispatch systems comprising a main pneumatic motor having av diaphragm, a normally closed controlling valve for the motor, an electro-magnetic device for opening the controlling valve, a pair of auxiliary motors each having a diaphragm movable under fluctuations in pressure in the system, electrical circuits each including said electro-magnetic device, a circuit closer connected with the diaphragm of each auxiliary motor and constructed and arranged to close one of the respective circuits through the electro-magnetic 'device, and a circuit breaker movable with the diaphragm of the main motor to break one of said circuits the main valve approaches the limit oi its movement in one direction.

15. Power control apparatus for pneumatic dispatch systems comprising a main motor having a reciprocable element, a movable controlling element therefor, an electromagnetic device for moving the controlling element, a pair of auxiliary pneumatic motors each having a diaphragm movable by variations in pressure in the system, elec trical circuits each including said electromagnetic device, a slidable stem movable by the diaphragm of each auxiliary motor, a circuit closer carried by each stem and operable to close one of the circuits, respectively, through the electro-magnetic device, and a circuit breaker operable by the reciprocable element of the main motor as the latter approaches its limit of movement in one direction for interrupting one of said circuits.

16. Power control apparatus for pneumatic despatch systems comprising a pneumatic motor having a diaphragm, a controlling valve for the motor, an electro-magnetic device for operating the valve, an electrical circuit including the electro-magnetic device, a sliding circuit breaker for interrupting said circuit, said circuit breaker having an axially elongate recess, and a part actuable by the motor and engaging the recess for actuating the circuit breaker.

17. Power control apparatus for pneumatic despatch systems comprising a pneumatic motor having a diaphragm provided with a sliding, spring pressed stem, at normally closed valve for controlling the motor, said valve having a. stem constituting the core of a solenoid, an electrical circuit including the solenoid, a pair of normally contacting resilient elements in said circuit, a non-conducting circuit breaker movable between said members to interrupt the circuit, and lost motion connections between the circuit breaker and the diaphragm stem.

18. A power control apparatus for a pneumatic transmission line comprising a main valve and a plurality of pneumatic motors, one of said motors acting, upon decrease in pressure in the transmission line, to admit pressure fluid to one of the motors for actuating the main valve, and another motor acting upon increase in pressure in the transmission line, to cut ofi pressure fluid from the main valve actuating motor to allow the main valve to close.

19. Power control apparatus for a pneumatic transmission line comprising a valve, and electro-magnetic means operative upon slight decrease in )ressure in the transmission line due to t e insertion of a carrier therein to initiate opening of the valve and upon slight increase in pressure in the transmission line incident to the discharge of a carrier therefrom to initiate closing of the valve.

20. Power control ap aratus for a pneumatic dispatch system aving a transmission line, comprising a valve, a pneumatic motor for opening and closing the valve,

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