US1951367A

US1951367A - Pneumatic dispatch tube apparatus

Info

Publication number: US1951367A
Application number: US500443A
Authority: US
Inventors: John T Needham
Original assignee: General Conveyors Ltd
Current assignee: General Conveyors Ltd
Priority date: 1930-12-06
Filing date: 1930-12-06
Publication date: 1934-03-20
Anticipated expiration: 1951-03-20

Description

March 20, 1934. J. T. NEEDHAM PNEUMATIC DISPATCH TUBE APPARATUS Original Filed Dec.

INVENTOR JOHN T. NEEDHAM l am ATTORN EYS March 20, 1934. J, T NEEDHAM 1,951,367

PNEUMATIC DISPATCH TUBE APPARATUS Original Filed Dec. 6, 1930 3 Sheets-Sheet 2 W. 5 23u71 Z3/72 76 @i 4p .3.5i 1E, `9A/Z5 y`7Z INVENTOR JOHN T. NEEDHAM ATTORNEYS 6, 195o 3 Sheets-sheet s J. T. NEEDHAM PNEUMATIC DISPATCH TUBE APPARATUS Original Filed Deo.

40 gf@ @60m S wO m TE N N R E N O WT. .Ww l A N. H O Y .UB w. @I y .Z A 6 f m .7/// 13S :L 7i

March 20, 1934.

Patented Mar. 20, 1934 UNITED STATES PATENT OFFICE to General Conveyors Limited, Montreal,

Quebec, Canada, a corporation of Canada Application December 6, 1930, Serial No. 500,443 Renewed March 30, 1932 28 Claims.

Important objecs of the present invention are, to provide a sending terminal device of generally improved design for a pneumatic dispatch tube apparatus; to provide an improved sending terminal device designed to expedite the passage of inserted carriers from a carrier inlet to a dispatch tube; to provide for positive and quick pneumatic propulsion of inserted carriers from the inlet to the dispatch tube; to provide satisfactory valve means for controlling said carrier propulsion; to provide a multiple sending terminal device of improved design; to provide a multiple sending terminal device formed of a plurality of terminal units designed for

convenient assembly

1,5 in varying numbers; to provide a multiple sending terminal device wherein each terminal has means for controlling the carrier propelling air, and means are provided for automatically restoring a previously operated air control means of one 2G terminal to normal position when the control means of another terminal is operated; and to provide a sending terminal device with other irnproved features of design which will be described hereinafter.

In the drawings, Fig. 1 is a top plan view of the multiple terminal device;

Fig. 2 a horizontal section taken through one end of the device, on the line 2--2 of Fig. 4;

Fig. 3 a horizontal section taken through the opposite end of the device, on the line 3.-3 of Fig. 4;

Fig. 4 a vertical section taken on the line 4-4 of Fig. 1;

Fig. 5 a vertical section taken on the line 5-5 of Fig. 4; and

Fig. 6 a vertical section taken on the line 6-.6 of Fig. 5, showing one of the control levers depressed.

In the present instance the device comprises three sending terminal units detachably joined together and forming a compact assembly. Ihe number of units may be varied according to the needs of the service. Each unit includes two sending terminals together with improved air f control means for causing positive Jtransmission of carriers from said terminals to and along the dispatch tubes connected to the device. A single manifold supplies compressed air to all of the units for the propulsion of the carriers, and the air control means for the various terminals are all operaively connected together by means which cause the return of a previously operated control means to normal position when another one is operated.

Each terminal unit includes a narrow, box-like casing 1, preferably formed by a single casting. Said casing has

vertical end walls

2 and 3, a bottom wall 4 and a central partition web 5 dividing the interior of the casing into halves. Each half is subdivided by vertical webs 6 and 7 60 and by horizontal webs or

walls

8, 9, 10 and 11. Thereby at each side of the partition web 5 a number of spaces and chambers are dened, in-v cluding a space 12 containing part of the air control means, an air passage 13 directly below 65 space l2, an air supply space 14 below said passage, a valve chamber 15 below space 14, and upper and

lower air chambers

16 and 17 along the central web 5. Each chamber 17 opens downward into a discharge nozzle 18 formed upon the bot- '(0V tom 4 and a dispatch tube 19 is connected to said nozzle. At their upper. ends the casings 1 .are closed by four flat, elongated cover plates 20 which are disposed edge to edge and extend transversely across all of the casings. Said plates are sup.- 75 ported upon flanges 21 formed upon the upper ends of the casings 1, and upon anges 22 formed upon

cover sections

2,3. The cover sections 23 are mounted upon the outermost casings 1, at opposite sides of the assembly and detachably held 30 by screws 24. Other screws 25 detachably hold the plates 20 to said supporting 'anges. y

`The casings 1 are all similarly formed and th various webs within the different casings aline edgewise throughout the length of the assembly. 95 Therefore at each side of the central web 5 the various spaces and chambers lie in straight rows. Spaces Y12 open, one into another in succession,

as do the air supply chambers 14. Each casing is formed at one side with walls 26 which sepa- 9 rate the

chambers

15, 16 and 17 of one casing from the corresponding chambers of the next adjacent casing and abut sealing flanges 26a formed on said next casing. Abutting walls 26b upon the successive casings separate the passages 95 13. Along their

ends walls

2 and 3 the successive casings are formed with inwardly extending flanges 27 which abut and are detachably fastened together by screws 28 to holdthe casings together. The flanges 27 extend across 100 the communicating spaces 12 and across the communicating spaces 14, and the screws 28 are accessible through said spaces. At their opposite ends the rows of communicating spaces 12 are closed by the detachable cover sections 105 23. At one end, the rows of spaces 14 are closed by a detachably mounted plate 29 and at the opposite end an air supply manifold 30 opens into both rows. This manifold is detachably fastened to the endmost casing 1 and is connected to an |10 istering with the bushing ports 44. This valve a shouldei` 54 bearing against the web 9.

air supply pipe 31. Removal of one of the cover sections 23 and the plate 29 gives access to the screws 28.

Two of the cover plates 20 serve to cover the two rows of chambers 16 and are formed with bell mouths 32 defining entrances for the insertion of carriers. Each entrance is located directly over one of said chambers and is normally closed by a pair of trap doors 33. The latter open downward and are yieldably held closedby springs 34. Beneath each entrance, within the casing, is a tube section 35, 'disposed in vertical alinement with the entrance. At an intermediate point said tube section is formed with an enlarged threaded portion 36 which is screwed into an aperture in the wall 11 separating the

chambers

16 and 17 so that the tube section extends into both chambers. Its upper end is flared to form a bell mouth spaced a short distance below the carrier entrance and its lower end terminates near the nozzle 18. Downwardly opening trap doors 37 are mounted upon the lower end and are normally held closed by springs 38. Above the wall 11 the tube section is formed with air ports 39 and its bell mouth is notched as at 40 for screwing it into place. The tube section forms a carrier transmission passage as will be explained hereinafter.

For each terminal there is a valve mechanism to control a flow of air for propulsion of carriers throughthe tube section 35 and through the dispatch tube 19. Within each chamber 15, which is in effect a lateral branch of chamber 17, is mounted a cylindrical valve bushing 41. The latter is disposed vertically and has its ends fitted in apertures 42 formed in the web 10 and the casing bottom 4. Just beneath the web 10 the bushing is formed with ports 43 at one level, and at a lower level it is formed with ports 44. A cylindrical valve 45 is tted to slide within the bushing and is formed with ports 46 for regis cup-shaped and opens upward into the valve bushing and the space 14.

The webs 8 and 9 are formed with apertures 47. and 48 respectively vertically alining with the apertures 42. A plate 49 is disposed within the upper space 12 and is formed with a depressed central portion 50 fitting in the aperture 47 and centrally formed with an aperture 51. Said depressed portion of the plate is formed with a downwardly extending valve cage 52 which terrninates in an annular beveled valve seat 53 which is fitted in the web aperture 5l and provided with The upper aperture 47 is large enough to permit the insertion of the shoulder 54 through it for mounting the valve seat in place. Screws 55 detachably fasten the plate 49 to the web 8 and hold the shoulder 54 against the web 9. The plate 49 forms a valve guide and a support for certain control means within the space 14.

A beveled disk valve 56 is adapted to seat upward against the valve seat 53 and is formed with guide lugs tting in the cage 52. Said valve is formed with a tubular stem 57 extending above and below the valve. Above the valve said stem slidably iits through the plate aperture 51 and extends upward into the space 12. Below the valve the stem is formed with a disk valve 58 formed to slidably iit in the upper end of the bushing 41 to close communication between'the air supply space 14 and the interior of the bushing. Valve 45, Within the bushing, has fixed to it a vertical stem 59 which extends upward through `the tubular stem and is slidably tted in it.V A

compression spring 66 bears against the under side of valve 58 and encircles the stem 57 of valve 45. At its lower end said spring bears upon several abutment pins 6l which extend upward through apertures in the bottom of valve 45 and are carried by a bottom plate 62. The latter closes the lower end or the valve bushing and is detachably held to the bottom of casing 1 by screws. Normally, as shown at the right hand -side of Fig. 4, the spring 60 holds the valve 56 against its seat 53 and holds the valve 58 elevated above the bushing 41.

Plate 49, within each upper chamber 12, is formed Vwith a pair of upstanding ears 63 and plvoted between said ears is an angular operating lever 64. Said lever has an operating handle 65 extending upward through a slot in the adjacent cover plate 20, and a lateral arm 66 which extends across the upper ends of the valve stems 57 and 59. For operatively contacting said stems arm 66 bears a roller 67. kAt its free end said arm bears a suitably insulated electrical contact disk 68. Beneath said disk the plate 49 bears a pair of spring contact ngers 69 suitably insulated. These lingers extend upward and are flared apart at their upper ends to receive the contact 68 between them when the lever is operated.v Thereby, an electrical circuit, not shown, is closed and, in the usual manner causes the operation of a timer which, in turn controls the operation of a compressor and causes a ilow of air to the terminal device.

Detachably supported by the upstanding leversupporting ears 63 are brackets 70 each of which rotatably bears a grooved pulley 71. In the present instance, with three terminal units, there are four of these pulleys for each row of terminals, two of the pulleys being disposed between the operating levers and two at the ends of the row. All of the pulleys are at the same level and in each row they are in the same Vertical plane. The brackets 70 at the ends of the rows are provided with bracket extensions 72 Y which rotatably-bear cross-over pulleys 73. The latter are all disposed at a level below that or" the pulleys 71 and'in planes at right angles thereto. Each valve stem 59 also rotatably bears a pulley 74, to provide clearance for which, the tubular stem 57 is out away at one side as at 75. These pulleys 74 are disposed in the same verticaly planes with pulleys 71 and normally are at the same level as 4the pulleys 70, or substantially so. Trained around all of the pulleys is a ilexible strand in the form of an endless chain 76. The latter passes over the pulleys 7l, under the pulleys 74V in a serpentine course and under the cross-over pulleys '73, there`- by making cross-over connections between the two rows of terminals. For l accommodating said cross-over connections the end closure sections 23 are outwardly bulged. The chain has only suicient slack to permit the depression of one ci the pulleys and its connected valve stem 59 at a time. Consequently when a handle is voperated to de-` press one of said pulleys a previously depressed pulley in either row is automatically elevated to normal position by the tension of the chain.

In the operation of the device a carrier is in# serted intoone of the entrances 32 of a terminal whose control means are in the normal position, shown at the right hand side of Fig. 4. Here the valve 56 is in closed position against the seat 53 and valve 45 is in elevated closed position so that communication between the air supply space 14 and

chambers

16 and 17 is cut off. Also, the valve stems 57 and 59 are in elevated position and their upper ends are coincident. The carrier is inserted by thrusting it through the trap doors 33 and into the transmission passage dened by the tube section 35, the door springs 34 automatically closing the entrance behind the carrier. The control lever 64 is then operated to engage the contact 68 with the fingers 69 to close the timer circuit and start a flow of air through the manifold 30 and into the spaces 14. Said operation of lever 64 also depresses valve stems 57 and 59 and their

connected Valves

45, 56, and 58. Depression of valve 56 opens communication between space 14 and the upper chamber 16. Valve 45 is also in open position but Valve 58 is in a position within the bushing 41 and shuts off communication between space 14 and lower chamber 17. Air which has been admitted to upper chamber 16 enters the upper portion of the tube section 35 and forces the inserted carrier out of the tube section through the trap doors 37, whereupon the latter are closed by their springs 38. Such operation of one of the terminals is shown in Fig. 6.

The connection for a now of air into chamber 16 exists only while the handle is held in operated position, ordinarily only a moment. When the handle is released the spring 60 automatically elevates valve 56 to closed position and elevates the valve 58 to open position. Such an adjustment is shown in Fig. 4, at the left hand side. Air then iiows through the

bushing ports

43 and 44 into the chamber 16, nozzle 18 and dispatch tube 19 for the propulsion of a carrier therealong to its destination.

Valve 45 remains in its lower, open position, after the return of the operating lever to normal position, until another one of said levers is operated. Then a tension will be exerted upon the chain 76 which will elevate the previously depressed pulley 74, valve stem 59 and valve 45 to normal closed position.

The trap doors 33 prevent escape of air while it is flowing into chamber 16 and tube section 35 and trap doors 37 prevent escape of air through the tube section to the entrance while the air is owing into chamber 17 and the dispatch tube. Therefore if a carrier should be inserted into the entrance 32 while air is still flowing into the dispatch tube, as the result of a previous operation, escape of said air through the entrance will be prevented by the trap doors 37.

The various parts Within veach casing 1 are readily removable through the top of the casing. For removal of the control means for one of the terminals the appropriate cover plate 20 is removed and the plate 49 is released from its connections Within the space 12. Then, plate 49, switch 69, contact lever 64, valve cage 52 and the

valves

56, 58 and 45 are all removable upward as a unit. When it is required to remove one of the transmission tubes 35, the adjacent cover plate 20 is removed, giving access to the upper end of said tube and permitting it to be unscrewed and Withdrawn upward.

The device provides for positive and quick pneumatic propulsion of the carriers from the terminal entrances to the dispatch tubes. It is also designed for convenient installation, maintenance and operation. The Various units are interchangeable and are designed for ready assembly into a compact form. All of their internal parts are readily accessible and removable for cleaning, repairing and replacement.

What I claim is:

1. A sending terminal head for a pneumatic dispatch tube line, comprising means dening a carrier entrance; an inwardly opening trap clo'- sure for said entrance; a carrier passage leading -from. the entrance toward the tube line; an exit trap closure for said passage spaced therealong from said entrance closure and opening toward the tube line; a communication for leading air to said carrier passage for propelling a carrier through the passage, the entrance trap closure preventing escape of air through the entrance; a communication for leading air to the tube line at a point beyond said exit trap closure to propel a carrier through the tube line; and valve means to open and close said communications for the propulsion of a carrier through the said passage and through the tube line.

2. A sending terminal head for a pneumatic dispatch tube line, comprising means dening a carrier entrance; an inwardly opening trap closure for said entrance; a carrier passage leading from the entrance toward the tube line; an exit trap closure for said passage spaced therealong from said entrance closure and opening toward the tube line; a. normally closed communication for leading air to said carrier passage for propelling a carrier through the passage, the entrance trap closure preventing escape of air through the entrance; a communication for leading air to the tube line at a point beyond said exit trap closure to propel a carrier through the tube line; and valve means to first open said rst communication and close said second communication and next close the first communication and open the second one for the propulsion of a carrier through the said passage and through the tube line.

3. A sending terminal head for a pneumatic dispatch tube line, comprising means defining a carrier entrance; ,an inwardly opening trap olosure for said entrance; a carrier passage leading from the entrance toward the tube line; an exit trap closure for said passage spaced therealong from said entrance closure and opening toward the tube line; a normally closed lcommunication for leading air to the inner side of the entrance closure and to said carrier passage for propelling a carrier lthrough the passage, the entrance closure preventing escape of air through the entrance; a communication for'leading air to the tube line at a point beyond said exit trap closure to propel a carrier through the tube line; valve means manually operable to open said first communication and close said second communication for the propulsion of a carrier through the passage and the eXit closure; and means to automatically operate said valve means to close the rst communication and openy the second one for the propulsion of the carrier through the tube line.

4. A multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of sending terminal devices each connected to a dispatch tube line and comprising a carrier entrance, an inwardly opening trap closure for said entrance, a carrier passage leading from the entrance toward the tube line, an exit trap closure for said passage spaced therealong from said entrance closure and opening to-ward the tube line, a communication for leading air to said carrier passage for propelling a carrier through the passage, the entrance closure preventing escape of the air through the entrance, a communication leading air to the tube line at a point beyond said exit trap closure to propel the carrier through the tube line, and valve means to open and close said communications for the propulsion of. a carrier through said passage and through the tube line; and means to automatically restore said valve means ci one sending terminal device to normal position when the valve means of another device is operated for the propulsion of a carrier.

5. A sending terminal head for a pneumatic dispatch tube line, comprising means defining a carrier entrance; an inwardly opening trap closure for said entrance; a carrier passage leading from the entrance toward the tube line; an exit trap closure for said passage spaced therealong from said entrance closure and opening toward the tube line; a communication for leading air to said carrier passage for propelling a carrier through the passage, the entrance trap closure preventing escape of airthrough the entrance; a corrununication for leading air to the tube line at a point beyond said exit trap closure to propel a carrier through the tube line; valve means to open and close said communications for the propulsion of a carrier through the said passage and through the tube line; an electric switch to 'control a supply of air to said communications; and manually operable means to operate said switch and operate said valve means.

6. A sending terminal head for a pneumatic dispatch tube line, comprising means dening a carrier entrance; anl inwardly opening trap closure for said entrance; a carrierV passage leading from the entrance toward the tube line; an exit trap closure for said passage spaced therealong from said entrance closure and opening toward the tube line; a communication for leading air to said carrier passage for propelling a carrier through the passage, the entrance trapY closure preventing escape of air through the entrance; a communication for leading air to the tube line at a point beyond said exit trap closure to propel a carrier through the tube line; valve means to open and close said communications for the propulsion of a carrier through said passage and through the tube line; an electric switch to cause a dow of air to said communications; manually operable means to close said switch and operate said valve means to open said first communication and close said second communication tor the propulsion of a carrier through the passage and through the exit closure; and means to automatically open the switch and operate the valve means to close the rst communication and open the second one for the propulsion of the carrier through the tube line.

7. A multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of sending terminal devices each connected to a dispatchtube line and comprising a casing provided with a carrier entrance, a passage within the casing for directing a carrier from said entrance to the tube line, air conduits. within the casing for admitting air to said passage and to the tube line for the propulsion of the carrier, valve means within the casing to control the flow of air through said conduits, means to prevent escape' of airl through the entrance, and manually operable means to operate said valve means; and means to automatically restore the valve means of one of said terminal devices to normal position when the valve means of another of said devices is subsequently manually operated.

8. A multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of sending terminal devices each connected to a dispatch tube line and comprising a casing provided with a carrier entrance, a passage within the casing for directing a carrier from said entrance to the tube line, an air sup-r ply space within the casing, conduits leadingy from said space to the carrier passage and to the tube line for the propulsion of the carrier, and valve means within the casing to control the ilow of air-through said conduits; and means attaching the casings of the several devices side to side, the attached casings being formed at their opposed walls to place their air supply spaces in communication with each other.

9. A sending terminal head for a pneumatic vdispatch tube line comprising means dening a carrier entrance; a carrier passage leading from the entrance toward the tube line; a communication or leading air to said carrier passage for propelling a carrier through the passage; a communication for leading air to the tube line to propel the carrier therethrough; valve means to open and close said communications for the propulsion of a carrier through said passage and through the tube line means to prevent air delivered through said rst communication-from escaping through the entrance; and means to prevent air delivered from said second communication from escaping through the carrier passage to the entrance.

10. A multiple sending terminal head for a pneumatic dispatch tubesystem, comprising a plurality of sending terminals, each connected to a dispatch tube; a manually operable device for each terminal to controla now of air from a compressed air supply source to the terminal for propelling a carrier away from the terminal; and means to automatically restore a previously operated one of said devices to normal position when another one of said devices is operated.

l1. A multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of adjacent sending terminals, a manually operable device for each terminal to control a flow of air for propelling a carrier away froml the terminal; and a flexible strand trained to engage said air control devices and automatically restore a previously operated device to normal position when another one is operated.

Vi2. A multiple sending terminal head for a pneumatic dispatch tube system comprising a plurality of rows of adjacent sending terminals; a manually operable device for each terminal to control a flow of air for propelling a carrier away from the terminal; and a flexible endless strand trained to engage all of said air control devices and automatically restore a previously operated device to normal position when another one is operated.

13. A. multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of similarly formed, interchangeable sending terminal units attached together, each connected to a dispatch tube and including a manually operable device for each terminal to control a :dow of air from a compressed air supply source to the terminal for propelling acarrier away from the terminal; and means to automatically restore a previously operated one of said devices to normal position when another one of said devices is operated.

i4. A sending terminal head for a pneumatic dispatch tube system, comprising a casing open at the top; a cover member for the top of said casing provided with a carrier entrance; a dispatch tube line connection at the lower end of the casing in alinement with said carrier entrance; a carrier Vtransmission tube extending between said entrance and dispatch tube convmunication; and means to automatically close nection, detachably supported in the casing and formed for endwise upward withdrawal from the casing when said cover member is removed; and control means detachably supported within the casing for controlling a ow of air for the propulsion of'a carrier from the entrance through the transmission tube and the dispatch tube, the casing and said control means being formed for upward withdrawal of the latter through the top of the casing.

15. A sending terminal head for a pneumatic dispatch tube line comprising means deiining a carrier entrance; a carrier passage leading from the entrance toward the tube line; a communication for leading air to said carrier passage for propelling a carrier through the passage; a communication for leading air to the tube line to propel the carrier therethrough; valve means to open and close said communications for the propulsion of a carrier through said carrier passage and through the tube line including telescoping, relatively shiitable valve stems, a pair of valves iixed to one of said stems, one of said valves to control said passage air communication and the other to control said tube line communication, and a valve xed to the other stem to cooperate with said second valve for controlling said tube line air communication; means to shift said valves in unison for opening the rst valve, closing the second valve and opening the third valve for admission of air to said carrier passage; and means to close the rst valve and open the second valve independently of the third valve for admission of air to the tube line.

16. A sending terminal head for a pneumatic dispatch tube line comprising means dening a carrier entrance; a carrier passage leading from the entrance toward the tube line; a communication for leading air to said carrier passage for propelling a carrier through the passage; a communication for leading air to the tube line to propel the carrier therethrough; valve means to open and close said communications for the propulsion of a carrier through said carrier passage and through the tube line including telescoping, relatively shiftable valve stems and cooperating valves upon said stems.

17. A multiple sending terminal head for a pneumatic dispatch tube system, comprising a plurality of sending terminals, each connected to a dispatch tube; a device for each terminal to control a flow of air from a compressed air supply source to the terminal for propelling a carrier away from the terminal; and means to automatically restore a previously operated one of said devices to normal position when another one of said devices is operated. Y

18. A multiple sending terminal apparatus for a pneumatic dispatch tube system, comprising a plurality of carrier sending terminals each having a dispatch tube connection and a normally closed communication with a compressed air supply source to admit a carrier-propelling flow of air to said tube connection; a manually operable device for each terminal to open its said coma previously opened air flow communication of one terminal when the air flow communication of another terminal is opened.

19. A multiple sending terminal apparatus for a pneumatic dispatch tube system, comprising a plurality of parallel rows of adjacent carrier sending terminals each having a dispatch tube connection and a normally closed communication to lead a carrier-propelling flow of air` to said tube connection; amanually operable device forl each terminal to open said communication; andA means to automatically close a previously opened air flow communication of any one of they terminals in either row when the air flow communication of any of the other terminals in either row is opened;

20. A multiple sending terminal apparatus for a pneumatic dispatch tube system, comprising a plurality of parallel rows of carrier sending terminals, a manually operable device for each terminal to control a flow of air for propelling a carrier away from the terminal; and a flexible tension strand trained in operative engagement with said control devices of the rows and Aoperable to automatically restore a previously operated device in either row to normal position when another one of the devices in either row i operated. Y Y

21. A multiple sending terminal apparatus for a pneumatic dispatch tube system, comprising a; plurality of carrier sending terminals each having a dispatch tube connection and a normally closed communication with a compressed' 'air supply source to admit a carrier-propelling'flow of air to said tube connection, a common air supply connection for all of said communications; a manually operable device for each terminal to open its said air flow communication; and means.

to automatically close a previously opened air ow communication of one terminal when the communication of any one of the other terminals is subsequently opened. Y

22. A multiple sending head for a pneumatic dispatch tube system, comprising a plurality of similar, interchangeable, detachably connected terminal units each having a dispatch tube line connection and comprising a casing having a carrier entrance, a passage within the casing for directing a carrier from said entrance to the tube line, an air supply space within the casing, communications leading from said space to the carrier passage and to the tube line for the propulsion of a carrier; and manually operable valve means within the casing to control the ovv of air through said communications, the casings being disposed side to side and having their opposed sides open to place their said air supply spaces in successive communication.

23. A sending terminal head for a pneumatic dispatch tube line, comprising a sending terminal having a dispatch tube connection; a communication to admit a carrier-propelling flow of air to said tube connection; a shiftable closure for said communication; a manually operable device to shift said closure to open the communication; and an electric switch to control a supply of air to said communication and operable by said manually operable device to close the switch when the manually operable device is operated to shift said closure to open position.

24. A sending terminal head for a pneumatic dispatch tube line, comprising a sending terminal having a dispatch tube connection; a'communication to admit a carrier-propelling flow of air vto said tube connection; a shiftable closure for said communication; a manually operable device to shift said closure to open the communication; an electric switch to control a supply of air to said communication; an operative connection between said manually operable device and the switch to close the switch when the manually operable device is operated to shift said closure to open position; and means to automatically open the switch independently of the closure when the said device is manually released. y

25. A multiple sending terminal apparatus for a pneumatic dispatch tube'system, comprising a plurality of carrier sending'terminals each having a dispatch tube connection and a communication with a compressed air supply means` to admit carrier-propelling air to a dispatch tube connectedr to the terminal; a shiftable closure device for each of said communications manually operable to open the communication; and a flexible Ytension strand trained in operative connection with said closure devices to automatically Vshifta previously opened one of the closure devices to closed position when another` one of said devices is manually operated to open position.

26. A multiple sending terminal apparatus for a pneumaticdispatch tube system, comprising a plurality of carrier sending terminals each having a dispatch tube connection and Aa communication with a compressed air supply means to admit carrier-propelling air to a dispatch tube connected to the terminal; a shiftable closure device for each of said communications manually operable to open the communication; pulleys carried by said closure devices and shiftable therewith; pulleys mounted in fixed positions; and a flexible tension strand trained by said iiXed and shiftable pulleys to automatically shift a previously` opened one of the closure devices to closed position when another one of said devices is manually operated to open position.

27. A multiple sending terminal apparatus for a pneumatic dispatch tube system, comprising a plurality of side -by side rows of carrier sending terminals, each terminal having a dispatch tube connection and a communication with a compressed air supply means to admit carrier-propelling air to ia dispatch tube connected to the terminal, a shiftab-le closure device for each of said communications manually operable to open the communication; and a flexible tension strand trained in a serpentine course and in operative connection with the closure devices of both rows to automatically shift a previously opened one oi` said devices to closed position when another one of the devices is manually shifted to open position.

28. A sending terminal apparatus for a pneumatic dispatch tube system, comprising a plurality of sending terminals each having a dis- Y patch tube connection and also a communication to lead a carrier-propelling iiow of air to said tube connection; a shiftable closure member for each of said communications; a manually operable device for each of said-closure members to shift it to open the communication; a plurality of electric switches to control supply of airto said communications and each operable lby one of said manually operable devices to close the switch when the said device is operated to shift