The Pneumatic Despatch Tube System of the Batcheller Pneumatic Tube Co. / Also, Facts and General Information Relating to Pneumatic Despatch Tubes

by Birney C. Batcheller

Fig. 39.
INTERMEDIATE STATION RECEIVING AND TRANSFER APPARATUS.—VERTICAL SECTION.

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The carrier is discharged down a chute, L, which has a buffer at the bottom, and from the chute it rolls off on to a table. The buffer is made similar to the buffer in the open receiver already described. The cylinder and piston M, that operate to tilt the receiving tube D, are supported upon the base of the apparatus under the closed end of the receiving tube. The cross-head of the piston- and connecting-rods travels between guides that are made a part of the upper cylinder head. The movement of the piston in the cylinder M is controlled by a piston slide-valve exactly similar to the one shown in Fig. 35. The slide-valve is moved, in the same manner, by the air compressed ahead of the carrier when it is brought to rest in the air-cushion D. The air is conducted from the air-cushion to the controlling slide-valve through a small pipe, N, Fig. 36. This pipe leads to one of the trunnions, where it has a joint to allow for the tilting of the receiving tube. When the carrier is discharged from the receiving tube, it raises a finger, O, Fig. 37, located just outside the tube. Raising this finger pulls the rod P, Fig. 36, extends the spring Q, turns the lever R, and catches the pawl S, under the end of the controlling valve stem. When the carrier has passed down the chute and allowed the finger O to drop down, the spring Q turns the lever R back to its original position and moves the controlling valve. This causes the receiving tube to return to a horizontal position, where it is ready to receive the next carrier.

At first this apparatus may seem a little cumbersome, but nothing could work better. It is certain in its action and almost noiseless. Carriers are received, discharged, and the receiving tube returned to its normal position in four seconds, and it can be done in less time if necessary.

The Intermediate Station Receiving and Transfer Apparatus.

—One other form of receiving apparatus remains to be described, and this is the apparatus used at intermediate stations to intercept all carriers intended for that station and to send the others on through the tube to the next station. A side elevation of the apparatus is shown in Fig. 38 and a vertical section in Fig. 39. The tubes are led into an intermediate station, carried upward, and then, with a bend of one hundred and eighty degrees, are connected to the top of the receiving and transfer apparatus, as shown in the diagram, Fig. 26. The object of this arrangement will be seen as we describe the apparatus. Referring to the sectional drawing, Fig. 39, the connection of the tube A is seen at the top. As in the other receivers, the current of air arriving from the tube A is deflected through slots, B, into a passage, C, made in the frame of the apparatus. From this passage it enters the tube D through the slots E. The tube D leads to the sending apparatus and on to the next station, as seen in Fig. 26. The carriers are received in a closed section of tube F, which forms an air-cushion, similar to the closed receiver last described. This receiving tube F is made a part of what we might term a wheel. This wheel fits accurately into a circular casing and is supported by two trunnions or axles, upon which it revolves. The wheel has a broad flat rim, G, that covers the end of the tube at H when the wheel is revolved, and, in the normal position in which it is shown in the figure, covers the interior openings I, J, K, and L, in the casing. Leather packing is provided around each of the openings to prevent the escape of air between the face of the wheel and the interior face of the casing. From the bottom of the receiving tube F a passage, M, leads past a check-valve, N, to the tube D. When a carrier arrives from the tube A, it descends into the receiving tube F, compressing the air in front of it. This compressed air begins to escape through the passage M, but the high velocity of it closes the check-valve N as much as possible. A stop on the stem of the valve prevents it being closed entirely. The small opening past the valve allows some of the air to pass, thereby preventing the carrier from rebounding on the air-cushion. As soon as the carrier has come to rest, the check-valve N, by its own weight, opens wide, and the carrier, by its weight, settles gradually down to the bottom of the receiving tube. The wheel containing the receiving tube and the carrier will then be revolved by the cylinder and piston O, which is operated by compressed air taken from the tube through the pipe P. If the carrier is for this station, the wheel will rotate through an angle of forty-five degrees and discharge the carrier through the opening J, down the chute Q, from which it will roll on to a table arranged to receive it. If, however, the carrier is intended for some other station, the wheel will rotate through an angle of ninety degrees and discharge the carrier through the opening K into the tube D, and it will go on its way to the next station. This selection of carriers is brought about in a comparatively simple manner. At the bottom of the receiving tube F there are two vertical needles, R and S, shown upon a larger scale in Fig. 40. The needles R and S are contained in tubes having an insulating lining which keeps them out of electrical contact with the frame of the apparatus. Wires a and b make connection with the needles through metal plugs that form a guide for the needles, and through the springs U and V. Directly below the needle R is an insulated spring clip, W, held by two bolts and connected to the wire e.

Fig. 40.
A DETAIL OF THE INTERMEDIATE STATION RECEIVING AND TRANSFER APPARATUS.

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