US2016946A - Pneumatic dispatch system - Google Patents

Description

Oct. 8, 1935. J. M. SCANLAN PNEUMATIC DISPATCH SYSTEM 2 Sheet-Sneet 1 Filed Sept. 20, 1932 1935 J. M. SCANLAN PNEUMATIC DISPATCH SYSTEM Filed Sept. 20, 1952 2 Sheets-Sheet 2 INVENTOR Zz /AWZ ATTORNEY Patented Oct. 8, 1935 UNITED STATES PATENT OFFICE by mesne assignments, to The Lamson" Com.-

pany, Syracuse, N. Y., a corporat'ibn'of Massachusetts Application September 20, 1932,.Serial-Ne. 633,951.

8 Claims. (01'. 2243-28).

This invention relates to pneumatic dispatch systems: in which carriers are propelled from one point to another in the same building or in ad joining buildings by reason of a differential pres-- 5' sure created in the systems. It has particular reference to systems of sort adapted for the transmission of comparatively large carriers such as employed in the delivery of documents and the like although it is also applicable to the Smaller carrier systems whether operated by suction or pressure.

In the operation of pneumatic dispatch systerns especially of the large carrier type it has been found objectionable toattempt to transmit the carriers while the pressure difierential is largely interfered: with or destroyed by the opening of a discharge door associated with the particular sending tube to be used or by the presence of another carrier in the line. Such an attempt isparticularly objectionable in connection with lines which are commonly known as downsends", i. e'., in which a substantial drop occurs in the line at a point near the dispatching end of the same. When carriers are permitted tobe inserted freely into tubes of this sort there is a danger that several carriers: may become piled up at the lower end of a drop in the line while the discharge door is left open, for example, for an unduly long time. Under various other condi- 301 tions; also, it becomes desirable to know at one point or another along the line whether a tube is in the line, either in transit or awaiting removal at the discharge end.

It has been a primary object of the present invention toovercomethe difiiculties' previously encountered by theprovision of the automatic means for indicating when a carrier is intransit era-waitingremoval. In one form of the invention; as applied to a vacuum system, the desired indication is given by preventing the" insertion of a carrierinto a line so long as thepressuretherein adjacent the inlet is maintained at substantially atmospheric by virtue of some obstruction in the line or-due to the opening of the discharge door. To accomplish this result a pneumatically operated stop is provided, and it is withdrawn only upon the establishment of a substantial dif ference in pressure between the inside of the tube and the outside atmosphere.

In lieu of operating a stop the devices contemplated bythe present invention may bemade tosimply control a signal as-indi'catedl The same system may be employed; if desired, to operate an indicator in conjunctionwith a long line, for

example, which provided with a plurality of inlets. The: indicator may,v in that case, notify operator at onepoi nt that a carrier is in' the line at. a; point more: remote from the terminal so that no carrier should beinserted. A stop may. be providediin' this case inlieu of the indi- 5.

cater so as: tepo'sitiyely prevent introduction of a carrier' under the: conditions mentioned. A further application ot the invention may be made in. connection the removal of. carriers from a pressure systena- It. a. carrier is permitted to 10 remain at the discharge end of a pressure tube it may cause such a back. pressure tobe built up as to interfere withthe transmission of another carrier. 1-,. therefore,v contemplate the provision 0t an automatic signal. adapted. to give a continu- 15 ous indication so long as a-carrier remains at the discharge terminal;

Other. objects;andv advantages of the invention will: appear irons a detailed. description of an illustrative embodiment. otthe same which will now 20 be givenin. eoniunction. with the accompanying drawings, inwhich;

Figure I. is a-more. or less diagrammatic view of. a. pneumatic transmission tube partly broken away showing the inlet and discharge ends of 25 the same;

' Figure. 2 is a vertical). longitudinal, sectional View through the inlet portion of the tube;

Figure 3"i's a transverse sectional view through the tube nearthe inlet takenalo'ng the line 3-3 of Figure 2:

Figure 4 is a. diagrammatic view showing the connections at. the discharge end of the tube;

Figureeis a; diagrammatic view of a: signal applied to a modified form of system, and

Figure 6" is adiagrammatieview indicating a furtherapplicatibn of the invention.

Referring now'to Figures 1 to 4 of the drawings, the transmissiontube F0 may be of the usual construction as preferably employed in connec- 40' t'i'onwi'ththe transmission of largecarriers. As best shown in Figure 31 it is preferably elliptical in cross section so'as'to" adapt it" to receive carriers or the sameness-sectional form; A bell end ll maybeproviued at theinlet of the tube for the reception of the carriers to be transmitted while an'en'larged" chamber or compartment l2 may beprovid'err at the discharge end of the: tube in which the accumulation of a number of carriersmay bepermitted. 1 When the invention is applied to a suction or vacuum systems the lower or discharge: end of the tube may lie-connected by'a; branch line l3 to asuitable suction drum. I 4 from which the air is constantly evacuated, in a manner well known. A door I5 may be provided at the front of the chamber I2 to permit removal of the carriers as they are discharged into the chamber. In the handling of smaller carriers, such as employed on cash-carrier systems, it is generally the practice to discharge the carriers directly into an open receptacle. This is notalways considered practicable, however, in the handling of larger carriers since the force and consequent noise with which they would be discharged into an open receptacle would be excessively great. Accordingly, it is necessary in such a system to discharge the carriers into a closed chamber and the operator at the point of delivery must open the door of the chamber whenever a carrier is to be removed. At such a time it is impossible to establish any appreciable degree of vacuum or suction within the tube I0 due to the fact that. the suction line I3 will be placed in substantially open communication with the outside atmosphere through the chamber I2 and the door I5. It is undesirable under these circumstances to insert a carrier into the tube, particularly where the tube is provided with a sudden drop or downsend adjacent the inlet end. If the door I5 were held open for a sufiiciently long time, due to carelessness, or for other reasons, there would be danger of permitting an accumulation of several carriers at the bottom of the down-send with consequent danger of doing damage to the carriers and of clogging the system by virtue'of the fact that the suction when later developed, upon closing of the door, would be insufficient to cause a movement of all of the accumulated carriers.

In order to avoid the danger of a misoperation of the sort mentioned, astop I6 is extended through an opening in the wall of the tube at a point adjacent the inlet of the tube. This stop is so situated that a carrier II, a portion of which is shown in dotted lines in Figure 2, may normally be introduced a slight distance but may not be fully introduced or be drawn into the tube until the stop has been displaced. In order to automatically remove the stop I6 from the path oi the carrier whenever the tube is in condition for the pneumatic transmission of the carrier, a disc or plunger I8 is attached to the upper end of the stop. Normally the weight of this disc and the stop will serve to carry the latter into the position shown in Figure 2. However, under the conditions which will be mentioned, the disc I8 may be made to rise in the chamber I9 and thus cause withdrawal of the stop from the path of the carrier.

The under surface of the disk I8 is in constant communication with the outside atmosphere through an opening 20 provided at the front of the housing 200 which encloses the stop mechanism. The upper surface of the disk I8 is in communication through an opening 2| and a passage 22 through the casing 200 with the interior of the tube Ill. Now, under normal conditions the minimum flow of air through the tube III, which is ordinarily provided, is insufiicient to cause a pressure differential on the two sides of the disc I8 which will be great enough to lift the latter. However, when a carrier is inserted in the bell II at the inlet of the tube, suitable mechanism, whichis well known in installations of this type but is not shown in the drawings, will be brought into play to greatly increase the suction and thus create a partial vacuum of sufiicient magnitude to cause transmission of the carrier through the tube. The vacuum created at this time, acting through the passage 22 and the opening 2|, establishes such a difference in pressure between the twosides of the disc I8 that the stop IE will be quickly raised out of the path of the carrier and will permit the latter 5 to be drawn through the tube.- It will be obvious that if at the time the carrier is inserted in the bell II the door I5 is held open by the operator at the discharge end of the tube, the partial vacuum will not be set up in the tube It and hence 10 r the stop I6 will not be withdrawn. As soon as the door I5 is closed, however, the vacuum will be established in the manner indicated and withdrawal of the stop will take place. In a similar Way if a preceding carrier is still within the tube 15 I9 and serves to prevent the establishment of a sufiicient vacuum near the inlet end of the tube and in the passage 22, the stop I5 will not be withdrawn.

Referring now to Fig. 5, a modified arrange- 20 ment is diagrammatically indicated. The tube 25 may be a portion of a continuous line forming part of a vacuum system. It may, for example, be an intermediate section of a transmission line adjacent one of a plurality of inlets through which 25 carriers may be introduced into the line. It Would be quite undesirable to place a carrier into the line at an intermediate point if another carrier is already in transit from a point further out in the line. In the first place opening of the inlet door to admit the second carrier would interfere with the suction acting upon the first carrier and might cause it to drop if it were moving up- Wardly in a vertical rise in the line. Furthermore, there would be danger that the two carriers 35 would collide at the point where the branch through which the second carrier is inserted merges with the main line. To avoid these dangers I provide a small branch 26 from the main line leading to a chamber 21 at one side of a dia- 40 phragm 28. The chamber 29 at the opposite side of the diaphragm may be in communication with the atmosphere through an opening 30. A stem or rod 3| connected at one end to the diaphragm may be connected at its opposite end to a contact 45 member 32. One end of this member may be connected with a source of current 33 in series with an indicator 34. When a carrier is in the line 25 beyond the point of connection of the branch 26, a partial vacuum will be created in 50 the chamber 21 and the diaphragm will be lifted until the member 32 engages a contact 35 and thus closes the circuit through the indicator. The latter will be energized so long as the pressure in the line is maintained sufiiciently below 55 atmospheric. As the carrier passes the inlet of the branch 26 the suction will be relieved and the indicator circuit will be broken. Branch 26 may communicate with the main line at any convenient point, as at a point near one of the intake 0 terminals or at a point near the discharge end of the line. In the latter case a single diaphragm unit may control the operation of a series of indicators, one located at each of the intake points, and these will then be active throughout the 55 transit of a carrier. If desired, the indicator may be replaced by a stop, such as shown in Fig.

2, particularly if the diaphragm structure is located adjacent one of the intake branches, or the stop may be electrically operated by a magnet 7 energized in lieu of the indicator 34.

In Fig. 6 a further modification is shown. The transmission line 36 may be considered as part of a pressure system and may be provided with a discharge terminal 31. A carrier 38, indicated in 75 dotted lines, is adapted to extend into the tube a short distance until it is actually removed from the discharge end. In this way so long as it is left in the line it will create a back pressure. A branch 39 communicating with a chamber 40 on one side of a diaphragm 4| will transmit the back pressure to the diaphragm and lift the same against the atmospheric pressure in the chamber 42 which is in communication with the outside through a port 43. The diaphragm is connected with a contact arm 44 which is in series with a source of current 45 and an indicator 4B of any suitable type. When the diaphragm is lifted it will carry the arm 44 into engagement with a contact 41 to close the circuit through the indicator, which will remain energized until the carrier is removed. A series of indicators may be provided, if desired, one at each of a plurality of sending points.

While several forms of the invention have been disclosed in considerable detail, it is to be understood that various other modifications than those directly suggested may be made without departing from the general spirit and scope of the invention as defined by the claims.

What I claim is:

1. In a pneumatic dispatch system, a transmission tube having inlet and discharge ends, means for producing a partial vacuum within said tube, a stop effective under normal minimum flow conditions for preventing the transmission of a carrier through said tube, and pneumatic means controlled by the pressure within said tube for withdrawing said stop Whenever a suflicient vacuum is attained within the tube.

2. In a pneumatic dispatch system, a transmission tube having inlet and discharge ends, means for creating a differential pressure between the interior of said tube and the outside atmosphere, a stop adjacent the inlet of said tube for normally preventing the transmission of a carrier through said tube, and pneumatic means in free communication with said tube controlled by the pressure within said tube for operating said stop- 3. In a pneumatic dispatch system, a transmission tube having inlet and discharge ends, means for creating a differential pressure between the interior of said tube and the outside atmosphere, a stop effective under normal minimum flow conditions for preventing the transmission of a carrier through said tube, and pneumission tube having inlet and discharge ends, 5

means for producing a partial vacuum within said tube, a stop adjacent the inlet of said tube for normally preventing the transmission of a carrier through said tube, and pneumatic means in free communication with said tube for disabling said 10 stop whenever a predetermined degree of vacuum is established.

5. In a pneumatic dispatch system, a transmission tube having a normally open inlet and a normally closed discharge opening, means for ar- 15 resting a carrier when it is partially inserted in said inlet, means for establishing a partial vacuum in said tube when the carrier is partially inserted, and means for disabling said arresting means when said partial vacuum is established.

6. In a pneumatic dispatch system, a transmission tube having a normally open inlet and a normally closed discharge opening, means for arresting a carrier when it is partially inserted in said inlet, and means for disabling said arresting 25 means when a carrier is partially inserted, said disabling means being rendered inoperative when the discharge end of said tube is opened.

7. In a pneumatic dispatch system, a transmission tube having a normally open inlet and a. 30 normally closed discharge opening, means for arresting a carrier when it is partially inserted in said inlet, means for creating a minimum flow of air through said tube, said means providing a carrier propelling pressure differential upon partial insertion of a carrier, and pneumatic means operable upon establishment of said carrier propelling pressure differential to disable said arresting means.

8. In a pneumatic dispatch system, a transmission tube having a normally open inlet and a normally closed discharge opening, means for arresting a carrier when it is partially inserted in said inlet, means for establishing a partial vacuum in said tube when the carrier is partially inserted, 45 and a disc exposed on one side to the atmosphere and on the other side to the pressure within said tube for disabling said arresting means when said partial vacuum is established.

JOSEPH M. SCANLAN.

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