GB2084531A - Feeding articles to a sorter conveyor - Google Patents

Abstract

A sorter conveyor of the tilt tray type is provided with a feeding station comprising a transfer platform 14 located overhead the sorter conveyor. Articles to be sorted are successively supplied to the platform from a feeder conveyor 12, and means are provided for moving the articles on the platform in the direction of movement of the sorter conveyor to effect feed thereto in synchronism with the movement of the fast running sorter conveyor for well defined transfer of the articles thereto. The feeding station comprises means for automatically preventing articles from being fed to the platform as long as it is occupied by another article. For further increasing the sorter capacity two or more feeding stations may be provided, each accorded individual trays spaced one or more trays from each other. <IMAGE>

Description

SPECIFICATION A sorter conveyor This invention relates to sorter conveyors, and it is the purpose of the invention to provide a fast working sorter conveyor for relatively small articles such as envelopes containing developed film and photographic copies for delivery from a developing laboratory to the single customers or groups of customers or dealers. In such laboratories a very high number of single orders is handled daily, and it seems advantageous to make use of an automatic high speed sorter for facilitating the delivery of the processed film material to the customers.A realistic capacity of such a sorter will be some 10.000 units per hour, and it seems advantageous to use a sorter of the tilt-tray-type having a conveyor belt made of juxtaposed tray elements each operable to receive one article such as one of said envelopes and carry the same to an unloading area in which it is caused to be laterally discharged into any selected one of a plurality of stationary receiver compartments each identified by a destination code which is correspondingly accorded each article in any of a plurality of known manners, e.g.

by way of an operator operating a code input keyboard at the inlet end of the conveyor in accordance with the destination of each article fed to the conveyor.

While it is technically possible to design a sorter conveyor operating at the proposed high speed there seems to be an operational bottle neck in the very article feeding function, because an article feeding operator cannot catch up with the high capacity of the sorter. The articles should be placed in a reasonably well defined position on the single conveyor trays or corresponding partial lengths of the conveyor, and especially when the operator shall additionally read the destination code and read it in a coding keyboard for each article it is in practice not possible for one operator to feed the conveyor according to its full capacity.

A primary specific purpose of the invention is to provide an article feeder system enabling the operator to handle consecutive articles without special attention to a correct or well defined positioning of the articles on the sorter conveyor, or in other words an article feeder system which will automatically ensure a correct positioning of the articles on the conveyor. Another purpose is to provide a conveyor having a dual or multiple feeding station to enable two or more operators to feed the conveyor concurrently.

According to a first aspect of the invention there is provided a conveyor of the type referred to, the conveying means of which passes underneath a feeding station formed generally as a platform arranged endwise of an overhead feeding conveyor and associated with means operable to displace articles received on the platform in the moving direction of the underlying conveying means so as to effect delivery of consecutive articles to different surface portions of the conveying means in a well defined manner.

The said displacement means and even the feeding conveyor may be synchronized with the sorter conveyor such that the consecutive articles are delivered in the required exact manner to the sorter conveyor even when the latter operates at high speed.

According to another aspect of the invention there is provided a sorter conveyor operating at high speed and having closely juxtaposed tilt trays or similar carrier members for the single articles, two or more of the above feeding stations being arranged one after the other in the moving direction of the sorter conveyor and controlled in such a manner that two consecutive carrier members are loaded from two different feeding stations.With the close juxtaposition of the carrier members and the high operational speed of the conveyor it may be difficult or impossible to effect loading of two consecutive carrier members from one feeding station, if one article shall be delivered from the said platform before the,following article can be introduced onto the platform, but the required time for this operation cycle may well correspond to an effective loading of e.g. every second carrier member, while the remaining carrier members may then be correspondingly loaded from or by another feeding station. With the use of modern code handling technique there will be no problems in arranging for a corresponding sequential transfer of the destination codes of the respective articles to effect the required unloading of the articles in the respective correct unloading stations.

In the following the invention is described in more detail with reference to the drawing, in which: Fig. 1 is a general perspective view of a sorter system according to the invention, Fig. 2 is a more detailed view illustrating one feeding station thereof, Fig. 3 is a perspective view of a modified feeder system, Fig. 4 is a side view of a modified detail thereof, Fig. 5 is a similar view of a further modified detail, and Fig. 6 is a perspective view of another modified feeder system.

The sorter apparatus shown in Fig. 1 is generally designated 2 and comprises as a main part an endless conveyor belt 4 carrying a continuous row of carrier trays 6 which are moved in the direction shown by an arrow along the exposed upper run of the conveyor belt 4 in a generally horizontal position. The trays 6, however, are of the tilt-tray type operable to be tilted laterally to either one or the other side by means of a suitable tilt control system located in the apparatus 2 adjacent a row of unloading stations 8, whereby the trays during their movement along the said upper run may be tilted to unload any articles rested thereon into any selected one of the unloading stations 8. Articles are fed to the conveyor in a feeding station 10 comprising a transverse feeding conveyor 1 2.

Each article thus fed to a tray 6 is accorded a destination code, e.g. by way of an operator reading the destination and operating a keyboard for setting a corresponding code, whereafter the article will be unloaded into the correct one of the unloading station 8, as principally well known in the art.

The feeding conveyor 12 delivers the consecutive articles onto a feeder platform 14 located in a stationary position overhead the conveyor 4 and comprising a row of rollers 16 which are actively driven so as to cause an article received from the transverse feeding conveyor 1 2 to be moved further onto the platform 14, until it is brought against a stop (not shown) defining an article position generally overhead a tray 6 as passing underneath the platform 14.

Above the platform 14 is arranged a pusher system comprising -- in the example shown in Fig. 1 - a rotary cylinder 1 8 having secured to its surface two opposed rows of radial pins 20 and 22, which, when the cylinder 1 8 is rotated (by driving means not shown) will be swept across the platform 14, generally in the moving direction of the conveyor 4, such that the outer ends of the pins 20 and 22 are moved generally along the space between respective neighbouring rollers 1 6 to thereby push an article resting on the platform 1 A off from the platform for delivery to the underlying tray 6 as this appears at the right hand edge of the platform 14.The rotation of the cylinder 1 8 is synchronized with the movement of the conveyor 4 such that the tip velocity of the pins 20 and 22 corresponds to the velocity of the upper conveyor run and such that these tips generally follow the rear edge of the respective passing trays 6, whereby each article pushed off from the platform 14 will land in a well defined manner on one underlying tray 6. Therefore, an article supplied to the platform 14 will be accelerated rapidly by the pins 20 or 22 and pushed onto the trays 6, whereafter another article may be fed to the platform and unloaded onto a tray by the action of the following set of pins 22 or 20.

Between the active operations of the two sets of pins 20 and 22 at least one empty tray 6 will pass underneath the station 10 and not get loaded by any article. In order to enable all or most of the trays to be used there may be arranged one or even more additional feeding stations, one being indicated in dotted lines showing the associated transverse feeding conveyor 12'. In this additional station trays are loaded which have passed the first station 10 out of operational synchronism with the operation of the pusher means 1 8.In some large size sorters it is well known to use two or more parallel feeder stations and more or less complicated control means for effecting article feeding to the sorter conveyor in some well defined or arbitrary sequence, whereby the destination codes should be transferred to the main drive register in the same sequence; in the system here disclosed each feeding station may simply cooperate with its own preselected trays 6, which are normally unable to receive articles from the other feeding station or stations, whereby the sorter may operate at very high speed without article collisions and without any complicated control equipment, in practice as two or more individual sorters integrated into one common structure as far as the main sorter conveyor is concerned.

A practical feeder arrangement is shown in more detail in Fig. 2, where the main conveyor 4, the trays 6, the transverse feeder conveyor 12 and the roller platform 14 will be recognized. The overhead pusher structure is constituted by a short belt 24 arranged for endless movement about two rollers 26, one of which is connected with a motor 28 operating in synchronism with the main conveyor so as to drive the lower run of the belt 24 with the same speed and direction as the conveyor 4. The belt 24 is provided with the pins 20 and 22, though with the latter set of pins optionally only.Adjacent the rear end of the roller platform 14 is arranged a rigid end stop member 30, and between the delivery end of the feeder conveyor 12 and the front end of the roller platform 14 is arranged a retractable stop plate 32 mounted on pivot levers 34 connected with a vertical lift control unit 36 so as to be liftable to an article feed stop position and lowerable to the released position shown in Fig. 2. The rollers 1 6 are positively driven to suit the velocity of the feeder conveyor 1 2, but the driving means of the rollers are not shown in the drawing.

When correctly positioned the pins 20 should be located approximately above the rear edge of an underlying tray (shown somewhat offset in Fig. 2), and for each full movement cycle of the belt 24 there will pass two trays 6 underneath the roller platform, the pins 20 following the rear edge of one of these trays. The rear edge of the other tray may be foilowed by the other set of pins 22, or an additional feeder station may be provided to serve these respective trays.

Above the delivery end of the feeder conveyor 12 is arranged two article sensors S3 and S1, of which S3 senses whether an article is approaching the delivery end while S, is intended to sense whether there is an article present in front of the stop plate 32 and sense the passage of the rear end of the article as the article is passed onto the roller platform. Above the receiving end of the platform is arranged a third sensor S2.

The gear motor 28 is provided with an indexing signal producing unit (not shown), which is connected with a central control unit, to which also the sensors S1S3 and the lift control cylinder 36 are connected. The central control unit is programmed so as to ensure that an article approaching the roller platform 14 will be allowed to proceed if it can safely reach its ready position on the platform before it is engaged by the pusher pins 20, while it will otherwise be stopped by the raised stop plate 32 and then be released when it can proceed without interfering with the pusher pins. This type of control can be achieved in various detailed manners, but it is believed that in the present connection it will not be necessary to exemplify the control functions.

Instead of the pusher pins being arranged on an overhead pusher structure they could be mounted underneath the upper run of the conveyor 4 and cooperate with means for selectively raising them in and above the space between two consecutive trays 6 so as to project above the top level of the rollers 1 6 in the spaces between respective neighbouring rollers, control means further being provided for lowering the pusher pins once they have served their purpose and return them into their initial positions underneath the conveyor 4.

Alternatively the rear edge portion of each tray may be made as a row of fingers pivotally arranged between an inactive rearwardly projecting position and an active upwardly projecting position, in which the fingers pass through the spaces between the neighbouring rollers 1 6 to bring along an article resting on the rollers; suitable actuator means may be provided for raising the fingers when the conditions for pushing off the article are established.Especially pusher pins operating from beneath should be controlled so as to take into account the presence of mounting means endwise of the rollers 16; in fact it may be sufficient to support the rollers are their rear ends and to make the rollers long enough to enable the pins to get raised while they move between the said mounting means and the position in which they may meet the edge of an article resting on the platform.

The stop plate 32 may be avoided if the feeding conveyor 12 is controlled by start/stop operation. For achieving a rapid start/stop controlled movement of the articles on this conveyor the conveyor belt 12 may be replaced by a plurality of constantly operating conveyor rollers or wheels surrounded by a horizontal plate member having recesses through which the top portions of the conveyor rollers or wheels are exposed, the plate member being vertically displaceable between a lower inactive position beneath the top plane of the rollers or wheels, in which these act as a conveyor for the articles, and a raised position above the said level in which the articles are lifted out of driving engagement with the rollers or wheels so as to rest on the plate member until it is lowered again.

Another modification is illustrated in fig. 3. The feeding conveyor 12 is a multiple belt conveyor having belts 40, the upper runs of which pass along the top side of two consecutive support plates 42 and 44, of which the first is located at the receiver end of the conveyor and is provided with grooves or slots 46 underneath the respective belts 40. The plate 42 is tiltably supported by brackets 48 such that its downstream end may be swung upwardly by any suitable control means, e.g. a cylinder 50. It will be understood that an article laid onto the raised plate 42 will not be moved away therefrom until the plate is lowered so as to bring the article in contact with the continuously moved belts 40, whereby this arrangement substitutes the stop member 32 of fig. 2.

The transfer platform 1 4 is designed according to a similar principle. A multiple belt conveyor 52 having belts 54 is mounted overhead the tray conveyor with the upper runs of the belts 54 moving continuously in the moving direction of the tray conveyor and with approximately the same speed. Normally the belts 54 or rather their upper runs are received in grooves 56 in a horizontal plate member 58, which is mounted so as to be vertically displaceable between its raised, belt receiving position as shown in full lines and a lowered position as shown in dotted lines, in which an article having been loaded onto the plate member 58 will be supported by the belts 54 and thus be moved beyond the end of the belt conveyor 52 for delivery to an empty tray 6.In order to secure a well defined acceleration and delivery of the article the belts 54 may be of a suitable high friction type.

Instead of lowering and raising the plate member 58 it would be possible to arrange for raising and lowering of the belts 54.

The plate member 58 may receive a new article from the feeding conveyor as soon as the plate member 58 has been raised to its initial position and the article transfer from the belts 40 may take place without positive drive on the plate member 58, because the feeder conveyor 1 2 will push and partly throw the article onto the plate member.

The vertical movements of the plate member 58 may be controlled in any suitable manner as governed by the general control equipment of the sorter. In Fig. 3 it is illustrated that the plate member is vertically guided along rails 60 and lowered and raised by'means of a pair of cylinders 62.

In a preferred embodiment as illustrated in Fig. 4 the plate member 58 is supported on parallel pivot arms 64, which are caused to swing downwardly when the plate member is to be lowered. An associated horizontal displacement of the plate member may take place in the moving direction of the belts 54, whereby an initial acceleration of the article is induced before it is gripped by the belts 54.

A lengthwise movement of the plate member 58 may be utilized in a more direct manner for effecting the transfer of the article to the sorter conveyor, without assistance by any moving belts 54: If as shown in Fig. 5 the plate member 58 is provided with an upstanding ridge 66 along its rear edge, then a fast forward motion of the plate member will cause the rear edge of the article to be hit by the ridge 66, and thus the plate member may exert a forward throwing action on the article.

When the plate member is abruptly stopped and retracted the article will continue its motion, and the throwing action may well be so controlled that a resulting well defined delivery of the article to the relevant tilt tray 6 will be achievable without any belts 54 being needed.

In the embodiment shown in Fig. 5 the plate member 58 is a stationary member, and no belts 54 (Fig. 3) are used. The plate member 58 has an upstanding rear ridge 68 which is a separate rod member arranged so as to be reciprocally slidable over the surface of the plate member 58, biased rearwardly by means of springs 70. The outer ends of the rod member 68 project beyond the side edges of the plate member 58, and the underlying trays 6 are rearwise provided with selectively actuatabie pins 72 operable (by selector means not shown) to be raised to a position in which they will engage the said outer end portions of the rod member 68 and thus cause the rod member to be displaced across or along the plate member 58 as the particular tray 6 passes underneath this member. Control means should be provided for retracting the pins 72 as these are about to drive the rod 68 beyond the downstream edge of the plate member 58, whereby the rod 68 will return very quickly to its initial position upon having pushed an article onto the underlying tray 6.

The invention also comprises the disclosed method of feeding the articles to the transfer platform and pushing them off the platform with the required speed and synchronism for well defined delivery to the respective trays.

Claims (6)

1. A sorter conveyor of the type comprising a conveyor belt made of juxtaposed carrier elements and moved past a loading station, in which articles to be sorted are fed to the carrier elements from a feeder conveyor, and past a plurality of unloading stations, in each of which actuator means are provided for selectively causing the articles to be unloaded laterally from the carrier elements, characterized in that the loading station comprises an article transfer platform arranged overhead the conveyor belt and endwise of said feeder conveyor and associated with means operable to effectively displace an article received on the platform in the moving direction of the underlying conveyor belt so as to effect delivery of consecutive articles to said carrier elements in a well defined manner with respect to the landing positions of the articles on the carrier elements.

2. A sorter conveyor according to claim 1, in which the transfer platform is stationary and is provided with surface grooves extending parallel with the moving direction of the conveyor belt, pusher means being arranged so as to be movable in and along said grooves, projecting upwardly therefrom sufficiently to engage the rear edge of an article resting on the platform.

3. A sorter conveyor according to claim 1, in which said displacement means are steadily operating intermittently in synchronism with the movement of the conveyor belt, and in which control means are provided for admitting consecutive articles to enter the platform from said feeder conveyor only during an inoperative phase of the intermittent operation of the displacement means.

4. A sorter conveyor according to claim 1 or 3, in which the carrier elements are constituted by similar tray elements, and which comprises at least two loading stations having individual displacement means, these displacement means being operated in individual synchronism with the conveyor belt in such a manner that two consecutive tray elements are loadable exclusively from two different loading stations.

5. A sorter conveyor according to claim 1, in which the displacement means are passive pusher means operable to be selectively and temporarily actuated by engagement means associated with said carrier elements so as to be moved by the motion of the conveyor belt itself.

6. A sorter conveyor according to claim 1, in which the displacement means are constituted by selectively operable pusher means located on the conveyor belt.