US1600198A - Power controller - Google Patents

Description

Sept. 14, 1926. I 1,600,198

J. T. COWLEY POWER CONTROLLER Filed April 25, 1925 2 Sheets-Sheet 1 20 .0 177116711507": Jiunaf ozuZey.

129 w GEM 11 viii gs.

Patented Sept. 14, 1926.

JAMES '1'. cownEY, or :SYRRCUSENEW Yank, gssmlmn'iqifig Lmsfoi (ibniPAnY,

OF SYRACUSE, NEW'YQRK, A CORPORATION OF MASSACHUSETTS.

I hi n eii i n i li li to PO E it fo 'le'i s fdrJPneumtti despat'ch systeins fan'd felat'es nig fe particularly} to automutic'allyhztctugted CQlitlQlilfQ of the s -cstlledfniiniinuth fflgwiypeb' hih th p l ilt l jl i ll N0- 968,678 nu ustsmieio, fufnishs familr 7 ell times vpermi tted '21 continuous giir' new pf relajtlvely' small volume, ln'sufliciel t to 0- 'ell rf .;an pk n t ffj lll uli flowi, and

eliminating the timing device and thereof providing means hich isF 'pOnsiye directly to 'the change in pressure the ti'ans niss'icn tube, incidentfto disjch zinge of the last carrier therefrom, 'for 'in itia closure pf'the'cdntrclling Value. Inn l dance with e h present inx' entien siich i-esponse Of the pne'uinz tic to dischaifie qf the carrier 'results indirectly in equalizing the pressure upon 'oppcqsite sides ofsuch pneu- C mat-i0 the eby pei niitti ngcldsu e of the controlling i xlv'e byineans of a sprin brother 4 .Inh omp nyin T r i gs v P i fei'red. emliddiinent bf the invention is illusa d y M m em lar- N Fig. 1 beingfla diagrammatic 'eleyatlon, Pi i t y in se t q E O'W 'I h imPIQX cqntnoller installed betwe'en Qne trans issign tube of e jneumaticfsystem kind the exhaust header thereof;

station desk p o'vided' w'ith the id es iteif- "tion. The cbnespcnding "'i'eturn trathsinie l'iir'ery terminal 5 with an ezttensi'on 6 pewter controller hs it "u hdle. This cont-iol- 181 the einliddiiilnt illustnated'c crnp ises afhollcwcasing 10 having therein a cha nber 10f which communicates fieely fat 'all tiines'with the pipe leading to the suction header 9. A suhstz ntizilly l J-shaped piu titicn '01 septum :11, comprising substantially parallel upper and lo tyer alls 12 and 13 respectively, separates the main bddy of the chamber 1 0 fi'bin an iiilet chan ber 'le Which comrnunic zites diielctly nf ith the tube r lf e iip nd o' t" till li fid'liefi l PWII JU 3 6. i fpi i fi e valve ties '5 #1 1115; T Pi V I 1A t med t pe [he 1 "header 9.

carrier prop; 1mg fair f lb ii thi oli'h the e transmission line but at all times a small continuous flow of air through the trans mission line is permitted by the provision of a conduit leading directly from the pipe 6 to the pipe 8 outside of the controller casing 10. Vhile such an outside pipe is preferred, similar results may be obtained if desired by providing a small orifice through one of the walls of the septum 11,

seat for the outer edge or a flexible diaphragm 24 which is clamped against the flange 23 by the marginal flange 25 01 a downwardly concave cover -member 26 which' may be secured to the flange 23 in any desired manner, for example by means of bolts, not shown. The members 22 and 26 thus constitute a pneumatic main motor casingv which is divided by the diaphragm 24 into upper and lower chambers 27 and 28 respectively. The lower chamber 23 communicates freely at all times with the outer air by means of one or more large orifices 29 in the member 22 while the chamher 27 communicates with the atmosphere by means of a single very small orifice 29 preferably controlled by an adjustable nee dle valve. I

The central part of the diaphragm is preferably stifl ened by means of clamping plates 30 and 31 disposed upon its opposite sides and is secured to the upper end of the stem 32 of the main valve 17 by means of a bolt 33 which passes through the plates 30 and 31 and the central part of the diaphragm and has threaded engagement with an axial opening in the stem 32. For conve'nience in assemblage of the parts it-is preferred to provide the upper wall 21 of the casing lO with a central aperture which is normally covered by a removable plate 34 having a boss 35 provided with a guideway for thestem 32 of the valve; r

A rod 36, forming an extension of'the stem 32, has screw-threaded engagement at its lower end with a threaded opening in the head ofthe bolt 33. This rod 36 passes through a guide opening in the upper end of a gland 37 havingthreaded engagement with an opening in a boss 38 projecting from; the cover 26. One end of a compression spring 39 bears against the inner surface of the gland 37. This spring en circles the rod 36 and bears at its lower end againsta collar 40 secured to the rod 36. By sc'ewing. the gland 37 in or out the tension of the spring 39 may be varied, the tendency oi the spring being to depress the diaphragm 34 and retain it in the normal position indicated in full lines in Fig. 2. The upper end of the rod 36 is screw-threaded at 41 for the reception of an adjustable contact thimble 42. r

The cover 26 is provided at one side with an upstanding boss 43 which forms a support for the case of an auxiliary motor pneumatic comprising the lower saucer-like receptacle 44 having a radial flange 45 at its edge which forms a seat for the edge of an flexible diaphragm 46. The edge of the diaphragm is clamped between the flange 45 and the flange 47 of the downwardly concave cover member 48 of the auxiliary motor case The central part of the diaphragm 46 is preferably clamped between the stiffening plates 49 and is provided with a two-part stem comprising an upwardly extending member 51 and the downwardly extending member 59/ The members 50 and 51 have threaded engagement with each other at their opposed ends and clamp the plates 49 between them.

The member 50 of the stem, is furnished with a restricted axial passage 53 of small cross section which opens laterally thro'ugl'i the side of the stem at the point 54(outside of the auxiliary motor casing, and also at the point 55 within the casing and above the diaphragm 46.

r A valve disk 56 is securedto the lower end of the stem member 50 and cooperates with an annular valve seat 57 defining a large valve orifice 58 opening into the chamber 27 of the main motor and normally connecting said chamber through passages 59 and 60 with the chamber 14 and the transmission tube extension 6.

The stem member 51 slides in a'guide 7 opening in gland 61 having threaded engagement with a boss 62 upon the cover member 48 of the auxiliary motor casing and is provided at its upper end with'an adjustable contact member 65. A coiled spring 63 bears at its upper end against the inner surface of this gland while the lower end of the spring bears against a flange 64 upon the lower end of the stem member 51. The spring thus tends to depress the diaphragm 46 and to restore it to the normal position indicated in Fig. 2. By turning the gland 61 the tension of the spring may be varied.

A bracket 66 is secured'to the cover mem' 1 ber 43 of the main auxiliary motor and forms a support for a pivot pin 67 constituting the fulcrum for a lever 68, This lever is pivoted to swing in the plane defined. by the parallel stem members 36 and 51 of the main and auxiliary diaphragms respectively and at its end 69 is guided by passing through a vertical slot 70 in a bracket member 71 secured to the cover 48, The slot 70 is closed at its upper end as indicated at 70%(0 form; a limiting abutment for the end of the lever 69. This end'of the lever is normally held againstisaid abutment by a.

spring 73. Oneqend of the spring is secured to theend 72 of the lever; its other end being attached to-an eye bolt 7 a passing through a suitable opening in the flanges 23 and 25 and-having an adjustable nut 75 atits lower end. v j The operation of the device is substantial ly as follows; it beingassumed that when the transmission tube is idle the parts occupy the position indicated in full lines in Fig 2. Then in this position theicontact members 42 and 65 are both spaced from the lower edge of the lever 68: Under these conditions a minimuini low of air entersthrotigh the-open transmission terminalQ of the tube 3 and passes'through the outlying station tube 4, aipefi'and messed to'xthe exhauster;

ll ihenfacarrier'is inserted, in the transmission tube either at the point 2 or at the outlying station this ,niinimum flow-is cut off or substantially diminished with aresultant increa'sein the'vacu'um in the transmissionxline. fThisdecrease in pressure is immediately transmitted through the pars sage 59 and the openvalve orifice 58 to the chamber 271W-l13f8 it is effective to raise the diaphragm 524 against the resistance of :the spring 39 and thus to open the inam valve: 1.7.. As soon as the ni'ain valve'begins to open the vacuum, in the transmission tub'eis furtherincreased so that thediaphragm 24- rises Withiincreasing force until the main. valve is fully open.- As the main Valve approaches its fully open position the-contact member 42 engages the lower edge of the lever 68 andtilts the. latter to, the dotted line positionindic a-ted atfZGin Fig.2; thus tensioning spring 73.. This moves the end 69 of the lever downwardly and brings the lower edge of the lever into substantial engagement withzthe contact member 65 of the valve-stem 51.. v

WVhile thexabove operations have taking place the -,decrease3'(1 pressure in the passage 59, due first to insert on of the carrier, and second to opening of the-main valve, s

slowlvtransmitted through the passage 53' to the upper chamber 48 of the auxiliary motor.- As. the lower chamber 48 of this motor is always freely open to the atmosphere throughya vent {lh'the diaphragm tends to rise; but as the pressure in ;the chamber 48 drops much more slowly than that in the chamber '27 of the main diaphragmthe latter-has time torise to its uppermost position before the vacuum in the chamber 48 is suflici'ent to overcome the spring 63; When the vacuiun inth'e chainher 48 finally beceines great enoughto'overcome-the spring 63 theup'ward movement of the diaphragm is reven'ted by engagement of the'contact member 65:1vith theleverl'arm 69 The parts thus remain inthis position with the vahie'orific e 58wide5open'so' long as, a carrier remains in the transmission tube;

\Vhen the last carrier emerges from the YES its meet. Since the 'valvechamber :27 is now no longer connected to the transmission tube" and ezkhauster; atmospheric air leaks in through the aperture 29 until the presshre upon opposite sides of the diaphragm QA has been equalized whereupon the spring 39 i de-- presses the diaphragm 24 and closes the valve 17 thus cutting .01? the carrier @pro pelling air flow through the \trahsmission tube: I v a r a I As soon assuch fi'owi-s cut off-the pressure in the chamber 48* begins'sl ovvly ;to rise as air leaks :in'throughthe passage and after a short interval the spring :63 restores the valve 56 to its normal open-position. 1 I 13y the arrangemehtthus described the opening-of the main valve is accomplished automatically by theslight dropin pressure in the transmission tube incident to introducti-on of a carrier and such vali eaizs positively held open 'hntil the last carrier emerges from the; line. The slight increase in pressure incident to delivery of the last carrier then nitiates closure of the main valve. The device thus operates independently of any timing arrangement and solely in accordance Withcthe presence or i'absence of a carrier or carriers fromith transmis; siontube. 1 i 7 While [I haverherein illirstrated a preferred embodiment ofthe invention 1 wish it to be understood that various changes in relativeposition and proportion i at parts (as Well as the substitutioh of equivalents for the elements herein described .as fQr-mingthe combination may be made ivith'outxdepart' ing from-the spirit oft-he invention; andiin' my copending application Serial No. 25 766 filedApril 25,219 25; I have'disclo sedaii d claimed: a "modified arrangement fe udeter mining the time ofclosure of the atlXilifllj valve. a

I claim: i v 1. Pneumatic despatch apparatus [comprising a condui-t and an exhauster' Cannes ill) ed therewith, a controlling valve located in the conduit, a minimum flow of air through the conduit being permitted when the valve is in closed position, a motor pneumatic for opening said valve when a carrier is inserted in the conduit, one side of said pneumatic normally being exposed to transmission tube pressure, said pneumatic holding the valve wide open so long as a carrier remainsin the conduit, and means acting automatically upon delivery of the last carrier from the tube to cut off transmission line pressure from the pneumatic whereby to initiate closure of the valve.

2. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow of air through the transmission'tube, a minimum flow of air through the tube'being permitted when the valve is in closed position, a pneumatic normally exposed to transmission tube pressure, said pneumatic responding to decrease in pressure in the tube incident to insertion of a carrier in the latter whereby to open thecontrolling valve, said pneumatic also responding to pressure change in the tube incident to discharge of the lastcarrier from the latter, and means actuable by said pneumatic when responding to such last named pressure change for initiating the cutting off of such transmission tube pressure from the pneumatic.

3. Pneumatic desp'atch apparatus having a transmission tube, an exhauster connected therewith and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic for actuating said valve, said pneumatic being constantly exposed uponone side to full atmospheric pressure, a normally open passage admitting transmission tube pressure to act upon the opposite side of thepneumatic, and an auxiliary valve controlling said passage, said auxiliary valve remaining open while a carrier is in the tubeand closing when the last carrier is delivered from the tube.

4. Pneumatic despatch apparatus havinga transmission tube, an exhauster connected therewith and a valve for controlling the flow of airthrough the transmission tube, a minimum flow ofair through the tube being permitted when the valve is in closed position, a pneumatic for operating the valve, said pneumatic being exposed on one side to atmospheric pressure, a passage admitting transmission line pressure to act upon the other side of the pneumatic, a normally open auxiliary valve controlling said passage, means for closing said auxiliary valve, said means tending to respond to decrease in transmission line pressure incident to insertion of a carrier in the transmission tube, the Closing of said auxiliary valvebeing delayed until the carriers are discharged from the tube, and means permitting pressure to equalize upon opposite sides of the pneumatic when the auxiliary valve is closed.

5- Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic for operating theivalvepsaid pneumatic being exposed on one side to atmospheric pressure, a passage normally admitting transmission line pressure'to act upon the other side of the pneumatic, an auxiliary valve controlling said passage, an-auxiliary pneumatic responsive to decrease in pressure in the transmission tube for closing said auxiliary valve, and means actuated by the first named pneumatic for determining the time of closureot' said auxiliary valve. 7

6. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is inclosed position, a pneumatic for operating the valve, said pneumatic being exposed on one side to atmospheric pressure, a passage normally admitting transmission line pressure to act upon the other side of the pneumatic, an auxiliary valve controlling said passage, means tending to close the auxiliary valve upon insertion of a carrier in the transmission tube, and stop means actuable by the main motor positively to prevent closure of the auxiliary valve until the carrier has emerged from the tube.

7. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, and a pneumatic main motor for actuating the valve, said motor comprising a casing having a chamber therein, a flexible diaphragh forming one wall of said chamber, the outer surface of said diaphragm being exposed at all times to atmospheric pressure, means connecting the diaphragm to the valve, there being a passage normally open to admit transmission tube pressure to the chamber, an auxiliary valve for closing said passage, means tending to close said auxiliary valve when a carrier is introduced into the transmission tube, and means actuable by the aforesaid diaphragm for delaying closure of said auxiliary valve until the car-- rier is discharged from the transmission tube. 8. Pneumatic despatch apparatus having a transmission tube, an exhauster connected. therewith and a valve for controlling the flow of air through the transmission tube, a mini;

mitted when the val ve is in closed position, and a pneumatic main motor for actuating the' valvepsaid motor comprisinga casing having a chamber therein, a flexible dia phragm forming-one all of'sai d chamber, the outer surface otsaid diaphragni-being exposed at alltimes to atmosphericrpressure,

7 means co'nnecting*the diaphragm-to the siontubef valve, tl 1ere being-a passage normally open to admit transmission tube pressure to "the chamber, an 'auxi'liary valve for closing said passage, means tending to close the auxiliary valve when a carrier isinserted inthe'transmission tube, and means aetuable fby t-he main motor'tor-de'laying closure of the auxiliary valve until the oarrierhas been delivered'from the tube, a restricted passageloeing provided-to permit air'tolilejed into the motor chamber when the: auxiliary valve is 'closedto equalize the pressure upon opposite mating the tliaphragmto the valveftherebeing ajpassage normally 'open to" admit transmission tt'ih'e pressure tothe -ehamber, an

.attxili-ary' valve 'forelesm'g said passage, an

auxiliary pneumatic 3 for aetuatin g'the tWlXlliar'y val-v aid auxiliary pneumatic tending "to closefsaid' valve that transmission tube pressure drops below: normal 'tlue' lto" intro- ;duction o'f'a carrier ,and stop 'meansactu alil'e bythe aforesaid diaphra for delaying Llosure ofthe auiiil-iary'valv Uimtili thel'ast carrier has Tbeen'} delivered ffrom'ftlie transmis- '10. Pneumatic despatch-appa'ratus having a transmission-tube, an e-Xhauster' connected -tlierewith,-and a valve forcoiitrollii-ig the flow: of'air throughf'the" transmissio tube, a

minimum flow of are througlithe tabs being.

- permitted 7 When the valve is 4 in closed position, a pneumatic mainimotorcomprising' a .fieirible diaphragm for operating 't he ai'r controlling valve, said diaphragm; being eonnertedto Said-valve, an'au iiliary valve for controlling press-ure"con"d1 oin s in the pneumatic main motor, means inoluding'a reciprocating-part tending to close the "an-X- -iliai'y "vaive when a" ca'ijrier is inserted "in the transmission tube, a d" a stop positiona l t wea mevmefi at "said x ciip i' esir tis id t ies wi h? main'niotordiaphragm;

ing a casing having a chamber t-h 1 1; Pneumatio despatch apparatus having a transmission tube, an exhausterconnected therewith and a Valve for controlling the flow of air through the transmission tube, a minimum flow of air through'the tubebei'ng permitted When the valve is in closedposition, a pneumatic main motor for operating the air controlling valve, a'norma'lly open auxiliar y valve for controlling pressure conditions in the pneumatic main motor," means tending to close the auxiliary"valve when a carrier is inserted in the transmissioirtu-he, a. normally inoperative stop "forpreventing closure of the auxiliary valve, and a part actua ble by the pneumatic main motor for setting said stop in operative position.

'12. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith and a valve for" controlling the flo-W of air through the transmission tube, a minimum flow'of air througlr the"tubebe ing permitted Whenthe'val-ve'is incl-osed position, pneumatic main motor for operating the air controlling valve, an auxiliary valve, for controlling pressure conditions in the pneumatic main motor, a pneumatic auxiliary motor for' actuating itl ie auxiliary valve, said auxiliary motor comprising a casing "having a chamber thereing a flexible diaphragmformi'ng one Wall of said cham her, the outer surfae'eof said diaphragm means connecting said auxiliary motor diaphragm to the auxiliary valve," tlierebeing arestricted passage permitting-slowtransfer of transmission tulo'ei pressure to the chamber of-the auXi'li-aryirlotorwhereby the {diatherewith and a valve 'forcontroll'ng flow of air through the tube, a'inini umflov'v v M 1 of air being permitted When the"valve 1s'=1-n closed position, a pneumatic main motor-for operatlng the air controlling valve, an auX- {il-iary valv'e' for controlling pressureoondibeing exposed to 1 atmospheric pressure,

tionsin-th'e. pneumatic main iiiotoh'ap'nea matic auxiliary motor re;- actuating thea ili-ary valve, said are flexible diaphragmiorming one wall of said chamber, stem connecting "the latter diaphragm With the auxiliary'valve','-said'stem having 'a' restricted axially eXten' n pas'- sage permit-ting the slo vtrans'iero mission tube pressure to the chamber ofl he auxiliary motor iwliereby, uponidec rease 'belownormal in-transmission""tr ihe pressure due to introduction of a'c-arrier; theauX- iliary motor diaphragm tends to move after a slight delay thereby to close the auxiliary valve, and stop means actuable by the main motor for further delaying closure of the auxiliary valve until the carrier has been discharged from the tube.

14. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith and a valve for controlling the liowof air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic main motor comprising a flexible diaphragm having a stem, means connecting one end of the stem to said valve, a normally open auxiliary valve for controlling pressure conditions in the pneumatic main motor, an auxiliary pneumatic for actuating the auxiliary valve,'said auxiliary pneumatic having a stem con nected at one end to the auxiliary valve, the auxiliary pneumatic tending to close the auxiliary valve when a carrier is inserted in the transmission tube, a stop lever positionable .to prevent movement of the stem of the auxiliary diaphragm, and means normally holding said lever out of operative position, said lever being actuable by the maln motor to prevent closure of the auxiliary valve until the carrier has emerged from thetransmission tube.

15. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow 01": air throughthe transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic for operating the valve, said pneumatic being exposed on one side to atmospheric pressure, a passage admitting transmission line pressure to act upon the other side of the pneumatic, an auxiliary valve controlling said passage, an auxiliary pneumatic responsive to decrease in pressure in the transmission tube for closing said auxiliary valve, and a movable stop positioned during flight of a carrier through the tube to prevent said auxiliary valve from closing but permitting said auxiliary valve to close when the carrier emerges from the tube.

16. Pneumatic despatch apparatus having tuating the auxiliary valve, said auxiliary pneumatic having a stem connected at one the stop to release the auxiliary diaphragm and permit the auxiliary valve to close.

17. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic main motor comprising a flexible diaphragm having a stem, means connecting one end of the'stem to said'valve, a normally open auxiliary valve for controlling pressure conditions in the pneumatic main motor, an auxiliary pneumatic for actuating the auxiliary valve, said auxiliary pneumatic having a stem connected atone .end to the auxiliary valve, the auxiliary pneumatic tending to close the auxiliary valve when a carrier is inserted in the transmission tube, and a movable stop normally held in inoperative position against a limiting abutment by a spring, said stop being movable by the diaphragm of the main motor away from said abutment and into the path of the stem of the auxiliary diaphragm.

l8. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith, and a valve for controlling the flow of'air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic main motor comprising a,flexible diaphragm having a stem, means connecting one end of the stem to said valve, an auxiliary valve for controlling pressure conditions in the pneumatic main' motor, an auxiliary pneumatlc for actuating the auxiliary valve, said auxiliary pneumatic having a stem connected at one end to the auxiliary valve, the auxiliary pneumatic tending to close the auxiliary valve when a carrier is inserted in the transmission tube, a stop lever, a spring tending to swing the lever in one direction, an abutment for limiting such movement, means to adjust the tension of the spring and means for transmitting movement :trom the diaphragm of the main motor to the lever whereby to swing the latter away from its abutment and into the path of the stem of the auxiliary motor.

19, Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed position, a pneumatic main motor comprising a flexible diaphragm having a stem, means connecting one end of the stem to said valve, an auxiliary valve for controlling pressure conditions in the pneumatic main motor, an auxiliary pneumatic for actuating the auxiliary valve, said auxiliary pneumatic having a stem connected at one end to the auxiliary valve, the auxiliary pneumatic tending to close the auxiliary valve when a carrier is inserted in the transmission tube, and a stop lever swinging in the plane of movement of the stem of the auxiliary motor diaphragm and normally positioned to permit free movement of said stem, said lever being positionable by the main motor to prevent movement of the auxiliary diaphragm.

20. Pneumatic despatch apparatus having a transmission tube, an exhauster connected therewith and a valve for controlling the flow of air through the transmission tube, a minimum flow of air through the tube being permitted when the valve is in closed positlon a neumatlc main motor com r1s1n a flexible diaphragmhaving a stem, means' connecting one end of the stem to said valve,

an auxiliary valve for controlling pressure conditions in the pneumatic main motor, an

auxiliary pneumatic for actuating the auxiliary valve, said auxiliary pneumatic having a stem connected at one end to the auxiliary valve, the auxiliary pneumatic tending to close the auxiliary valve when a carrier is inserted in the transmission tube, the stems I l of the main and auxiliary motor diaphragm being substantially parallel, a stop lever swinging in the plane of said stems, the opposite ends of thelever being disposed in

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