Pneumatic Carrier Receive And Send Chamber

Abstract

A combination receive and send chamber in a pneumatic conveyor apparatus is connected to one end of a pneumatic tube for receiving pneumatic carriers transmitted by the tube. The chamber has an access opening, a stop and latch elements positioned to engage and hold a carrier conveyed to said chamber. The access opening, the stop and the latch are all adapted and positioned to positively latch a received carrier and yet remain in a non-interfering position with respect to carriers transmitted from the chamber.

Description

The present invention relates to pneumatic conveying systems and more particularly to a receiving and sending terminal or chamber for a pneumatic carrier.

Pneumatic conveyor systems have long been known and used for conveying articles between stations of a multiple station transfer system. Such systems usually incorporate a network of tubular conduits through which a transfer vehicle or carrier is propelled between stations by a pressure differential in the conduits. The differential may be provided by reducing the air pressure forwardly of the carrier or by increasing the air pressure rearwardly of the carrier, in either event causing the carrier to move through the tube.

Generally, individual carriers are provided with access doors which are opened to allow some object or item to be placed within the carrier, whereupon the carrier is placed within a conduit or tube and is transmitted, together with the item it contains, to a remote station in the system. Usually, the carrier itself includes a longitudinal housing provided with two enlarged ends which form seals with respect to the tubes so that an air pressure differential can be used to move the carrier within the tube.

In order to stop the carrier at a desired location or receiving station, the prior devices have included stops which are positioned in a carrier's path to halt it. Various types of stops have been proposed for use at receiving stations. The construction of the stops has depended on the particular configuration of the receiving chamber or terminal. For instance, if the carrier is in a horizontal attitude at its receiving station, then a relatively immovable abutment is adequate as a stop since, upon carrier arrival and upon cessation of any air pressure differential, a carrier will tend to remain stationary and gravity will not tend to move it backwards.

If the carrier is delivered downwardly in a vertical attitude to a chamber, a retractable latch abutment may be utilized to stop it and, upon retraction, release it from the tube. A "down" receive chamber with such a retractable latch is shown in U.S. Pat. No. 2,074,527, which discloses a pneumatic conveyor including a vertical conduit or tube terminating at a lower end in a "down" receive portion. Carriers transmitted to this end of the tube come to rest on a flat abutment surface of the latch and are supported there until the abutment is manually moved from the carrier's path and held in non-interfering relationship with respect to the carrier until the carrier is removed from the tube.

The latch of this patent includes a latch finger extending into the normal path of a carrier. An extension of the latch is adapted to be manually actuated to move an abutment portion of the latch out of the path of the carrier in order to release it from the conduit. Movement of the latch out of the carrier's path flexes a spring member of the latch, the spring member normally biasing the latch into the carrier's path.

Such a device has several inherent problems. For instance, if a carrier with two enlarged ends is utilized, the abutment elements of the latch must be flexed twice or at least held against the spring bias for each complete passage of the carrier, whether it is being sent or received. This results in undue wear of the elements involved. A further problem with such a device is that it does not positively hold the carrier at the station. Thus, if the effective pressure differentials acting on the carrier are inadvertently reversed, or reversed due to another operation of the pneumatic system, the carrier is lifted off the abutment and it is transmitted backwardly through the tube. One other problem with such a device is that when more than one carrier is received, and all are residing in a stacked relationship, removal of the abutment will allow all the carriers to discharge from the tube.

In yet another prior art receiving station, termed an "up" receiver, the carrier is in a vertical attitude but is delivered upwardly to the receive station, where it will remain against a stop in the carrier's path and held there against the pull of gravity only so long as the air pressure differential is maintained. Should this differential become equalized, such as by opening a door at the receive station to retrieve the carrier, or by cessation of operation of the pressure differential source, the carrier will fall downwardly within the tube and away from the receive station.

To solve the foregoing problem in an "up" receive chamber, latches such as the one disclosed in the system of U.S. Pat. No. 3,189,297 have been utilized. Such a latch yieldably extends into the path of a carrier and is deflected from this path by the forward movement of the carrier past it. As soon as the full length of the carrier passes the latch, the latch extends into the path again and presents a non-yielding abutment surface to the rear end of the carrier. Just as the carrier completely passes the latch, its forward end contacts an end abutment which is non-yieldable and which stops forward motion of the carrier. Thus, until the yieldable latch is thereafter actuated to non-interfering position, the carrier is held between the end abutment and the yieldable abutment regardless of the pressure differentials. When it is desired to transmit or to send a carrier from this station, the latch must be activated to a non-interfering position in order to release the carrier into the system.

Thus this type of latch has the disadvantage that, when a carrier with two enlarged ends is utilized, the yieldable latch is flexed twice for each passage of a carrier being received and at least once when a carrier is sent. This flexing could result in undue wear and strain on the latch parts. Further, this type of latch requires the provision of means to move it into a non-interfering position when a carrier is sent.

One other problem with such a latch is that if a plurality of carriers are transmitted to a receive station at the same time, a carrier next succeeding the first received carrier may operate to move the latch out of position in the tube and thereby allow gravity to pull the received carrier from the receive station and back down the tube, should the air pressure differential be equalized.

It has thus been one object of our invention to provide a receive chamber for a pneumatic carrier wherein a yieldable latch means cooperates with a forward enlarged end of the carrier to positively inhibit further longitudinal movement of the carrier within the system regardless of the condition of the effective air pressure differentials.

A second object of our invention has been to provide in a pneumatic conveyor system a vertical receive chamber wherein a yieldable latch cooperates with a forward end of a carrier to catch and hold it against any substantial movement within the system and yet is deformable to allow the carrier's removal from the chamber.

A third object of our invention has been to provide in a pneumatic conveyor system a combination vertical receive and send chamber provided with a stop and a latch for catching and holding the forward end of a received pneumatic carrier, which latch and stop is in a non-interfering position with respect to the transmittal or sending of a pneumatic carrier from the chamber.

A fourth object of our invention is to provide a vertical pneumatic carrier receive chamber including means adaptable to sequential positive latching receipt of a successive number of carriers.

Briefly, a preferred embodiment of our invention includes a pneumatic carrier receive and send terminal or chamber positioned at an end of a tubular conduit and provided with a terminal access door, a stop cushion and a carrier latch positioned between the stop cushion and the door for catching and holding the front end of a received carrier and remaining in a non-interfering position with respect to carriers transmitted from the terminal.

The terminal includes a connection to a pressure differential source which provides reduced or increased air pressure. The stop is provided at an end of the terminal opposite to its connection to the tubular conduit for engaging and halting the forward movement of the received carrier.

The carrier latch includes a deflectable leg inclined in the direction of travel of a received carrier within the terminal. This leg is connected at its carrier engaging end to a flat abutment leg situated normal to the carrier's path of travel. When an enlarged front end of a received carrier engages the inclined leg, it deflects until the enlarged end passes and contacts the stop cushion. At this point the inclined leg is urged to its usual position and the abutment leg engages the rear area of the carrier's enlarged front end to hold the carrier against further motion. The door to the terminal may then be opened and the carrier removed by tilting its bottom or rear end outwardly, thereby partially deflecting the latch which releases the carrier.

Since the latch of the invention is positioned above the access door, i.e., between the door and the stop, it does not interfere with the transmittal or sending of a carrier from the terminal into the attached conduit. Thus, no means are required for operating the latch when a carrier is transmitted. Further, since the latch is pivotally deflected by the movement of the carrier from the terminal, no means are required to operate the latch when a received carrier is removed from the terminal, thereby additionally simplifying the receiver structure. Finally, since the latch cooperates with the forward end of a received carrier, following carriers cannot actuate it and release the received carrier.

In one form of operation, a plurality of carriers can be received so as to be stacked within the conduit, one behind the other. In this situation, only the first carrier is latched, the remainder being held in position by the pressure differential. When the terminal access door is opened to remove the first carrier, the pressure differential, when the pressure in the terminal is lower than that behind the carrier, is equalized, thus allowing gravity to pull the remainder of carriers downwardly into the conduit. Following removal of the first carrier and closure of the door, the pressure differential is re-established, whereupon the next carrier is advanced against the stop, latched and held for removal.

In an alternate form of this invention, the latch includes a deflectable leaf-type spring positioned in the terminal opposite the access door, and a ledge abutment positioned between the door and the stop on the door side of the chamber. When a carrier enters the terminal, it deflects the spring as it passes and the carrier's forward motion is arrested by the stop. The spring then urges the carrier slightly toward the door so that its enlarged front end is moved over the ledge so as to latch the carrier. The carrier can be removed in the same manner as with the latch of the first-described embodiment.

The invention has the advantage of providing a carrier latch which is deflected only once during receipt of a carrier and not at all during the sending of a carrier, thereby decreasing unnecessary wear of the elements involved. In addition, the latch is only partially deflected upon removal of a received carrier, thereby further reducing wear.

A further advantage of the invention is that a carrier can be transmitted from the receive chamber without regard to the condition of the latch since it is not in the path of a transmitted carrier. Also, no additional means are required for operating the latch when a carrier is transmitted nor when a received carrier is removed.

A further advantage of the invention is that it provides a combination sending and receiving chamber which is operable in a pneumatic conveyor system motivated by air pressure differentials in the conduits regardless of the exact manner in which the differentials are applied to the carriers .

These and other objects and advantages will become readily apparent from the following detailed description and from the drawings, in which:

FIG. 1 is a cross sectional view of the receive-send terminal of a vacuum operated system with access door closed, showing a latched carrier and a subsequent following carrier in contact therewith;

FIG. 2 is a cross sectional view of the receive-send terminal with access door opened, showing a carrier partially removed therefrom and the following carrier falling down the tube;

FIG. 3 is a cross sectional view showing the forward end of a carrier deflecting the latch as the carrier is received;

FIG. 4 is a rear cross sectional view of the terminal showing the chamber access opening and the latch; and

FIG. 5 is a cross sectional view of an alternate latch embodiment.

Referring particularly to the drawings, a vertical pneumatic receive-send terminal or chamber, termed an "up" chamber, constructed in accordance with the present invention is shown at 10 in FIG. 1. The chamber 10 is connected to an end 11 of a pneumatic conduit 12 through a passage in the lower end of the chamber. The conduit 12 is connected into a pneumatic conveyor system. The chamber 10 may be self-contained or may be enclosed singly or together with other chambers within a substantially air tight housing (not shown). In either embodiment the chamber is adapted to positively receive successive carriers presented to it in a vertical attitude and is generally referred to as an "up-receive" terminal or chamber.

A forward wall of the chamber is shown at 13. This wall includes an aperture or access opening 14 provided with a hinged door 15. The door 15 includes gaskets 16 or other means for providing a substantially air-tight closure over the opening 14.

A pressure opening 17 is provided at the rear of the chamber for the purpose of providing a communication between the chamber and a pressure source which provides a pressure differential for propelling individual pneumatic carriers.

Of course, if the chambers are enclosed within a housing, the pressure opening 17 may comprise merely an aperture communicating between the chamber and the interior of the housing. In this event, door 15 on the chamber wall 13 could be omitted and a similar door utilized on an access opening in the enclosure housing.

The chamber 10 includes a stop or cushioning means 20 which is shown as a circular member with a central bore 21. The stop is located within a generally cylindrical portion 22 of the chamber and may be made from any suitable material including rubber, rubber-like foam, plastic, or the like. It is to be noted that stop 20 is positioned in the path of a pneumatic carrier and is generally opposite the chamber from the chamber's connection to the conduit 12. Thus the stop is in the correct position to cushion and stop a pneumatic carrier delivered to the chamber from the conduit.

A latch means 25 is positioned between the stop means 20 and the access opening 14. The latch comprises a yieldable inclined leg 26 and an abutment 27. The latch may be made from any appropriate material including spring steel or the like so as to be yieldable upon actuation by the passage of a pneumatic carrier.

Further included in the chamber are guides or deflectors 30 which depend from the upper cylindrical portion 22 of the chamber. The function of the deflectors 30 is to guide a pneumatic carrier toward the stop 20 as the carrier passes through the chamber.

Each pneumatic carrier has an intermediate body portion 36 and two enlarged ends 37. The enlarged ends of the carrier are of a diameter slightly greater than the intermediate body portion of the carrier and slightly less than the internal diameter of the conduit 12. Each enlarged end 37 is of a predetermined longitudinal thickness which is less than the distance between the stop 20 and the abutment 27 of the latch. Thus the end of the carrier may completely pass the latch abutment 27 before contacting the stop 20.

In a typical receiving operation, a first carrier A is propelled through the conduit 12 into the chamber 10. This may be accomplished by lowering the pressure ahead of the carrier in the conduit and in the chamber (providing a vacuum at pressure opening 17), by increasing pressure in the conduit behind the carrier or by any other suitable means.

As the carrier A passes through the chamber, deflectors 30 urge it toward the upper cylindrical portion 22 of the chamber where stop 20 is located. As the carrier engages the yieldable inclined leg 26 of the latch, momentum is sufficiently great to cause the leg to yield and allow passage of its enlarged end 37, as shown in FIG. 3. When the enlarged end 37 passes the latch, the latch returns to its normal position (FIG. 1) and captures the enlarged end of the carrier between abutment 27 and stop 20. Of course, the carrier is stopped when its forward end engages the stop 20.

Subsequently, door 15 is opened and the carrier may be manually removed from the chamber by merely grasping the lower end and tilting it forwardly through access opening 14 (FIG. 2). During removal of the carrier, the latch is only partially deflected by engagement with the tilting end 37. It can thus be appreciated that although the latch is deflected by passage of the end 37 upon carrier delivery and by the end 37 upon carrier removal, no separate means are required for actuating the latch in either operation and its function is entirely automatic.

In the situation where vacuum is applied through the chamber 10, the opening of door 15 equalizes this vacuum and any subsequent carriers B and C, which have received behind carrier A, will be drawn by gravity back into conduit 12 in the direction of arrow X (FIG. 2). When the door 15 is closed, however, the vacuum is re-established and a subsequent foremost carrier (B) will be delivered to the chamber and the latching means (FIG. 3). In this manner the invention provides for the successive positive receipt and latching of a plurality of carriers.

In a typical sending operation, door 15 is opened and a carrier is presented to the lower area of the chamber toward conduit 12. Increased air pressure may be provided through pressure opening 17 or a vacuum may be established in conduit 12 for moving the carrier to a distant station. In this operation it is to be noted that the sent carrier never contacts or actuates the latch, nor is it necessary to move the latch in any manner. The latch thus remains in a totally non-interfering position with respect to a sent carrier.

An alternate embodiment of the invention is shown in FIG. 5, like parts of this embodiment being designated similarly to like parts of the preferred embodiment. This embodiment includes an "up" chamber 40 which is provided with a yieldable latch member or spring 41 positioned opposite access opening 14 and door 15. Just above opening 14 is an abutment 42. The abutment is positioned opposite the spring 41 and between the access opening 14 and stop 20. In addition, the abutment is at a distance from the stop 20, which distance is slightly greater than the thickness of enlarged carrier end 37.

Operation of this embodiment is similar to that of the previously described embodiment. As the carrier is conducted through the chamber, deflectors (not shown) urge it toward cylindrical portion 22. Momentum of the carrier is sufficiently great to carry its enlarged end 37 past an inclined portion 43 of abutment 42, which incline urges the carrier end against the spring 41, thereby deflecting it. By the time the carrier end engages stop 20, its longitudinally thickened end portion has passed abutment 42 and the spring urges the enlarged end portion of the carrier's forward end over the abutment. In this manner the carrier is positively latched.

Removal of the carrier from this latch is manually accomplished, by opening door 15, grasping the lower end of the carrier and tilting it forwardly through the access opening 14. This movement partially deflects spring 41.

A carrier may be introduced to a conduit from a chamber with the alternate latch by merely placing the carrier in the lower end of the chamber toward a conduit (not shown). Spring 41 and abutment 42 remain in a completely non-interfering position with respect to the sending operation. Also, it can be appreciated that the operation of this latch, both in receiving a carrier and in releasing it, is essentially automatic, no additional operating means being required for the latch.

Although both latch embodiments have been shown within an "up-receive" chamber or terminal, it is entirely within the scope of the invention to utilize them in a reversed position, for instance as in a "down-receive" chamber or terminal. Such structure could be particularly useful in a vacuum system which required a positive latching operation in order to prevent received carriers from returning upwardly to the system should the vacuum be inadvertently or otherwise re-established.

While we have particularly described a preferred embodiment of our invention, other modifications and alterations will become readily apparent to those of ordinary skill in the art, without departing from the scope of the invention, and we intend to be bound only by the appended claims.

Claims

We claim:

1. In a pneumatic conveyor apparatus, a combination sending and receiving chamber for an elongated article carrier transmitted between two stations connected by a pneumatic conveying tube, wherein each carrier includes a body portion with at least one enlarged end, said end having a diameter greater than that of the body portion but approximately equal to the internal diameter of the pneumatic tube, and said end being of a predetermined thickness measured in the direction of the longitudinal carrier axis, said chamber comprising,

a housing having an interior communicating with an end of a pneumatic conveyor tube and into which a carrier is conveyed through a passage therein by said tube,

an access opening in said housig distinct from said passage permitting access to said housing interior for insertion and removal of carriers relative to said housing interior,

stop means mounted in said housing interior for engaging a leading end of a received carrier conveyed into said housing interior by said pneumatic conveyor tube and for stopping said conveyed carrier, and

latch means mounted within said housing proximate the upper end thereof and between said stop means and said end of said conveyor tube for positively engaging the uppermost leading enlarged carrier end of a received carrier when said stop means has stopped said carrier proximate said opening.

2. Apparatus as in claim 1 wherein

said latch means is positioned between said access opening and said stop means so as to be in non-interfering position with respect to the insertion of a carrier into the access opening prior to the sending of the carrier through said tube.

3. A pneumatic conveyor apparatus as in claim 2 wherein said latch means includes an abutment mounted between said access opening and said stop means, said abutment engaging said leading enlarged carrier end when said carrier is stopped by said stop means.

4. A pneumatic conveyor apparatus as in claim 3 wherein said abutment of said latch means is positioned a specified distance below said stop means, said specified distance being approximately equal to said predetermined thickness of said leading enlarged end of said carrier.

5. A pneumatic conveyor apparatus as in claim 4 wherein said latch means further includes a yieldable member extending into the path of the received carrier to effect a yieldable engagement between said abutment and said stopped carrier.

6. A pneumatic conveyor apparatus as in claim 5 wherein said abutment is connected to said yieldable member and wherein said yieldable member and said abutment are deflected by the passage of a leading enlarged end of a received carrier but are adapted to positively engage said end when said carrier is stopped by said stop means in order to hold said leading enlarged end between said stop means and said abutment.

7. A pneumatic conveyor apparatus as in claim 5 wherein said yieldable member is mounted within said housing opposite said access opening and wherein said abutment is positioned between said access opening and said stop means opposite said yieldable member, the enlarged end of a carrier being located between said abutment and said yieldable member when held by said latch means.

8. A pneumatic conveyor apparatus as in claim 2 wherein said latch means is actuated once for each receipt of a carrier received in said housing from said tube and wherein said latch means is inoperative with respect to carriers transmitted from said chamber.

9. In a pneumatic conveyor apparatus, a combination sending and receiving chamber for sending and receiving elongated article carriers between stations connected by a pneumatic conveying tube, wherein each conveyed carrier includes two enlarged ends and an intermediate body portion, said ends being of a diameter greater than that of the intermediate body portion but approximately equal to the internal diameter of the pneumatic tubes, and each end being of a predetermined thickness measured in the direction of the longitudinal carrier axis, said chamber comprising:

a housing having an interior communicating with the end of the pneumatic conveyor tube and into which a carrier is conveyed through a passage therein by said tube,

an access opening in said housing distinct from said passage permitting access to said housing interior for insertion and removal of carriers relative to said housing interior,

stop means in said housing interior for engaging a leading end of a carrier conveyed into said housing interior through said pneumatic conveyor tube and for stopping said conveyed carrier,

latch means within said housing proximate the upper end thereof including an abutment mounted between said stop means and said end of said conveyor tube for yielding upon passage thereby of said leading enlarged end of a carrier conveyed through said tube as said enlarged end of said carrier moves into contact with said stop means, said abutment engaging said leading enlarged end of said conveyed carrier when said stop means has stopped said enlarged carrier end, thereby positively positioning said carrier to facilitate subsequent removal thereof from said housing by tilting and withdrawal through said aperture, and

said latch means being positioned between said access opening and said stop means so as to be in non-interfering position with respect to the insertion of a carrier into said access opening prior to the sending of the carrier.