Feeding apparatus for flat items processed in a mail sorting machine with pulleys located under transport deck

Flat item feeding apparatus (10) having a delivering section (12) for receiving a large batch of flat items on a transport surface (24, 26a, 26b) and a singulating section (14) for extracting these items one by one and transferring them downstream. The delivering section includes a transport device (22) for conveying the stacked on edge flat items towards the singulating section, a pushing device (30) for jogging the stacked on edge flat items during the conveying. The transport device has an endless belt (26a, 26b) protruding a transport deck (24) within a conveying zone B of length d of the delivering section and located a distance d2 from a downstream pulley (29a, 29b) and a distance d1 from an upstream pulley (27a, 27b), the distances d1 and d2 respectively defining determined conveying zone A, C in which the at least one endless belt remains below the transport deck.

FIELD OF THE INVENTION

The present invention relates generally to systems for handling flat items such as mail or other objects. It is directed more particularly to an improved apparatus and method for feeding flat items stacked on edge by automatically controlling their transport and their presentation to a singulating head of a sorting machine. The items are further processed and finally sorted into individual sort pockets located at the exit of the machine.

BACKGROUND OF THE INVENTION

For a long time now, various feeders exist in document processing systems for delivering documents such as sheets, letters, postcards, checks into these systems for further processing. These feeders generally include a delivery portion and a destacking or singulating portion. The flat items are typically placed onto the delivery portion and delivered to the singulating portion for further processing in a sorting section. Typically operators manually load the items taken from storage boxes, trays, tubs, carts or hampers into the delivery portion at the beginning of the operational cycle. They usually go on loading the items on the fly while the system is running. The items are picked off the stack by a singulating module which feeds a reading module with them one at a time. The optical character or bar code reader reads some indicia printed on the item (e.g. zip code) and generates a signal representative thereof. A computer then processes this signal for directing and diverting this individual item to a designated sort pocket in the stacking section of the system.

U.S. Pat. No. 4,595,188 relates to a speed control system for an envelope feeding mechanism used to feed envelopes to a pickoff device in a high speed mail sorting machine. The feeding mechanism includes a pair of toothed belts which convey the envelopes along an inclined surface. The side edges of the envelopes are received by a third toothed belt which is driven at an elevated position along a side panel. The belts are driven by a multiple speed electric motor controlled by electronic circuitry which automatically decrements or increments the motor speed if the envelopes are bunched together too tightly or too loosely. If the speed is decremented and the envelopes are still tightly bunched, the drive motor is stopped by a shutoff circuit which operates independently of the speed control circuit.

U.S. Pat. No. 6,318,717 is directed to a singulator for feeding documents one at a time onto the transport of a processing machine. The singulator includes a pick-off means and a stripper means for preventing multi-feeds of documents. The stripper means is comprised of two independent stripper assemblies which are mounted one above the other. Each assembly is comprised of an arm which is rotatably mounted to the machine at one end and which has a means at the other end for engaging any multi-fed documents. Each stripper assembly has basically the same structure except the arm of one stripper assembly is shorter than the arm of the other assembly whereby the assemblies contact a multi-fed document at different points.

U.S. Pat. No. 6,511,062 concerns an apparatus and method for controlling the presentation of articles to the singulation head of a system for singulating a stack of edge-mounted articles, for example mixed mail, which mechanism senses the instantaneous pressure at which the lead article of the stack is pressed against the singulation head. A feedback control may be provided responsive to a difference between detected instantaneous pressure and a desired target pressure for controlling at least one drive member in a manner so as to reduce such difference. Where there is a pick window of instantaneous pressure at which singulation can be effectively performed, a control may also be provided to inhibit operation of the singulation head when the instantaneous pressure is outside the pick window. Two vertically spaced pressure sensors may be provided on the singulation head to detect the angle at which the lead article is presented to the head and controls may be provided for the drive mechanism(s) to reduce the difference between the instantaneous angle detected and an optimum angle for singulation and/or to inhibit operation of the singulation head when the instantaneous angle is outside of a range where singulation may be effectively performed. The sensor preferably includes a lever extending from the surface of the singulation head which is moved by a distance dependant on the pressure applied thereto. A servo motor may be connected to the lever to apply a bias pressure thereto which bias pressure is determined by a control signal applied to the motor. The sensor may also include a position encoder generating an output indicative of lever position.

U.S. Pat. No. 7,195,236 discloses automated induction systems and methods for mail and/or other objects. In some embodiments, a system for automated loading of a side-by-side stack of thin objects to a feeder is provided. The system can include, e.g.: a) a transporter having a transport surface upon which a side-by-side stack of thin objects can be conveyed; b) a carrier, configured to carry a side-by-side stack of thin objects, over the transport surface; c) a pusher over the transport surface; d) the pusher and the carrier being movable relative to one another between a first position in which the pusher is inside the carrier behind a side-by-side stack of thin objects on the carrier and a second position in which the pusher is laterally displaced from the carrier, such that the side-by-side stack of thin objects on the carrier is laterally slid off of the carrier by the pusher.

While these types of feeders generally work rather well, those skilled in the art will admit they can still experience significant multi-feed issues in sorting large batches of flat items or mixed flat articles with a size and/or thickness that can significantly vary within the batch. The above prior art documents propose good solutions which are however sophisticated, e.g. involving speed control, pressure control or orientation angle control. Since it highly matters to avoid as much as possible a decrease in throughput, an increase in multi-feeds, an increase in damage, jamming and/or other problems, any improvement in the reduction of multi-feeds of flat items is sought after.

Accordingly, a need exists for a feeding apparatus that can overcome, among other things, the above and/or other issues with existing systems, in a manner as simple and efficient as possible.

SUMMARY OF THE INVENTION

The present invention provides a feeding apparatus for flat items that is particularly applicable to a mail sorting machine. Illustrative functions performed by such sorting machine include, feeding flat items, singulating flat items, transporting flat items through at least a portion of the machine, scanning flat items, printing on flat items, diverting, guiding and sorting flat items according to scanned information.

In accordance with the invention, the flat item feeding apparatus presents:

a delivering section for receiving a large batch of flat items stacked on edge on a transport surface;

a singulating section for extracting these items one by one and transferring them downstream;

said delivering section comprising:a transport device for conveying said stacked on edge flat items towards said singulating section,a pushing device supported above said transport surface for jogging said stacked on edge flat items during said conveying,
wherein said transport device further comprises:

at least one endless belt protruding a transport deck within a determined conveying zone B of length d of said delivering section and located at a determined distance d2 from a downstream pulley and at a distance d1 from an upstream pulley, the distances d1 and d2 respectively defining determined conveying zone A, C in which said at least one endless belt remains below said transport deck, the apparatus being characterized in that a supporting plate is disposed under the determined conveying zone B and in that the upstream pulley and the downstream pulley are both located under said transport deck at two different vertical levels for tensioning and maintaining said at least one endless belt against the supporting plate.

With this particular structure, said delivering section or transport surface comprises at least two determined conveying zones defining at least two conveying phases respectively performed essentially with transporting and pushing means. Indeed, this particular arrangement in the delivering section allows to simply solve current problems originating from two known factors, i.e. the pressure at which the batch of items is pressed against the singulating mechanism, and the angle of the batch relative to this mechanism. This pressure in the invention is optimized at the end of the delivery cycle when the flat items do not rest on the at least one belt any more. With both a high kinetic friction between the singulating belts and the flat item to be singulated, and a better distributed pressure and the lack of friction between the flat items and the conveying belts, the influence of the angle of presentation becomes less critical. The flat items of the large batch should only be stacked virtually vertically for assuring a successful singulation.

According to another feature, d equals at least d1+d2 and d1 is around 10 cm and d2 is around 25 cm.

Advantageously, at least one endless belt is a toothed belt in each notch of which can fit the thickest flat item.

Preferably, said singulating section comprises a forwardly-driven spring-loaded series of transverse endless belts which cooperate with a smaller series of endless belts, the cyclic position of which is changed every n flat items, e.g. 1 cm move every 20 articles, by a motor for limiting belt wear.

In one embodiment, a plurality of sensors is associated with said forwardly-driven spring-loaded series of transverse endless belts for detecting both the presence and the right presentation position of the flat item to be singulated. Said pushing device is removably mounted on said transport device which can drive it over the entire length of said large batch of flat items.

Advantageously, said pushing device is a paddle that can slide on a supporting shaft of the delivering section around which it can also pivot via a handle and a rotating ring while being driven by the at least one endless belt via at least one lug. the at least one lug of the paddle is received in the notch formed between two teeth of the at least one endless belt that drives the paddle, and presents a variable height for maintaining the coupling to said at least one belt over the entire thickness of said batch of envelopes.

Preferably, this large batch of flat items is held straight under a variable pressure between said paddle and said forwardly-driven spring-loaded series of transverse endless belts of the singulating section.

The foregoing in other objects, features and advantages of the invention will be apparent from the following more specific description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in more detail and first toFIG. 1, a mail sorting machine is generally designated by reference numeral10. Its main components are:

a delivering section12which receives flat items such as mail pieces like stuffed envelopes that are to be sorted;

a singulating section14at which the individual items are separated one at a time from the stack or batch of envelopes loaded on the delivering section;

a printing section16at which some sorting code or information is printed on each envelope;

a scanning section18at which the zip code and/or other sorting information imprinted on each envelope is scanned;

a sorting section20towards which the envelopes are transported, diverted, guided and stored in designated sort pockets; and

a transport and imaging computer (not shown) for controlling the mail sorting machine.

FIGS. 2 and 3illustrate in more details delivering and singulating sections forming the feeding apparatus of the mail sorting machine10. The delivering section12comprises a transport device22having a transport surface upon which stacked on edge envelopes can be conveyed. The batch of envelopes is moved forward by a conveyor comprising a transport deck24with two longitudinal openings for receiving two endless toothed belts26a,26b. The transport surface of the transport device22includes this transport deck24defining first and third conveying zones A, C, and a first part of the toothed belts26a,26bthat actively drives the envelopes resting on their protruding teeth; this first part which defines the second conveying zone B, rests on a supporting plate28of the delivering section12.

These toothed belts run around two pairs of pulleys27a,27b,29a,29blocated under the transport deck24and carried respectively by shafts27c,29c. Both upstream pulleys27a,27bare motorized and the two series of pulleys27a,27b,29a,29bare positioned at two different vertical levels vis-à-vis the transport deck.

The upstream driving pulleys27a,27btension the toothed belts26a,26bfrom below before these latter reach the level of the supporting plate28over the first operating zone A. The downstream driven pulleys29a,29balso tension the toothed belts26a,26bfrom below and force them to leave the supporting plate28by going down under the transport deck24over the third operating zone C. The supporting plate corresponding to the second operating zone B and of length d is positioned at a distance d1 from the upstream pulleys and at a distance d2 from the downstream pulleys. The length d equals at least d1+d2, i.e. this supporting plate spreads over at least half the thickness of the batch. The distance d1 is generally smaller than d2, e.g. d1 equals about 10 cm and d2 reaches around 25 cm.

A pushing device such as a paddle30is removably mounted on said transport device22. It can slide on a supporting shaft31of the delivering section around which it can also pivot via its handle30cand a rotating ring31amounted on this shaft31. Projecting parts or lugs30a,30bof the paddle30are received in respective notches formed between two teeth of the toothed belts26a,26bthat drive the paddle over the entire thickness of said batch of envelopes. Lugs30a,30bhave different heights to keep the paddle engaged with either toothed belt26aor toothed belt26b. Shorter lug30acooperates with toothed belt26ain conveying zones A and B whereas longer lug26bcooperates with toothed belt26bin third zone C where the toothed belts are under the transport deck24.

The singulating section comprises a forwardly-driven spring-loaded series of transverse endless belts32a-32d. These endless belts are superimposed from the transport deck24to a sufficient height for receiving envelopes on edge, typically 16 cm corresponding to C5 format.

As shown onFIG. 4, a plurality of optical sensors34a,34b,34cis associated with the forwardly-driven series of transverse endless belts32a-32dfor detecting both the presence and the right presentation position of the coming envelope to be singulated. First and second sensors34aand34binform on the right vertical presentation of the envelope with an angle tolerance range of a few degrees, e.g. 5 degrees. Third sensor34cat the bottom informs on the end of the batch of envelopes.

As shown onFIG. 5, the forwardly-driven spring-loaded series of transverse endless belts32a-32dcooperate with a smaller series of endless belts36a,36b,36cfor singulating envelopes from the delivering section for further processing in the sorting machine. The four forwardly-driven spring-loaded transverse endless belts32a-32dare driven by a stepper motor38whereas the three smaller singulating belts36a,36b,36care fixed. However, a dc gear motor40changes the cyclic position of these latter every n envelopes, e.g. 1 cm move every 20 envelopes, in order to limit belt wear.

The feeding apparatus described above operates as follows.

Delivering section12receives a large batch of envelopes loaded manually by an operator. The large batch is held straight on the transport deck24over the three conveying zones A, B, C between said paddle30and said forwardly-driven series of transverse endless belts32a-32d. Thanks to the specific arrangement of the delivering path in these conveying zones, the pressure on the large stack is better distributed over the entire length of the batch for optimizing its singulation. Starting from first zone A, the envelopes rest on the transport deck24, then on the toothed belts26a,26bin the second zone B and finally on the transport deck24again in the third zone C. The driving pulleys27a,27band driven pulleys29a,29blocated under deck24tension the toothed belts26a,26b. They maintain constantly both driven belts against the supporting plate28.

As zone B spreads over more than half the thickness of the large batch of envelopes, friction forces of this batch on transport deck24are strongly reduced with the protruding toothed belts26a,26bwhich drive it actively in combination with paddle30for providing a reduced final pressure between said transverse belts and the envelope to be singulated. This pressure could effectively be much more important if the entire large batch has to be moved by only the paddle with the belts located under the transport deck, or by only the toothed belts located completely above the transport deck. In the latter case, the packed thin envelopes received in the last notch before being singulated are released together and are likely prone to multifeeding.

Combining the contact with both the transport deck and the toothed belts provides an original and simple solution for optimizing the delivery of a large batch to the singulating device. When the first envelopes leave the teeth of belts26a,26b, they are released and fall gently on the transport deck24while being pressed by the following envelopes still driven by these belts and this paddle. Envelopes which rested in the same notch between two teeth of the belts gradually loosen for getting an optimum presentation position to the singulating belts32a-32dwhich are associated with the three optical sensors34a,34b,34c, the status of which being as follows:

Of course, the operator usually continues to load the envelopes on the fly by pivoting and sliding the paddle while the sorting machine is running.

While the invention has been shown and described above with respect to a preferred embodiment, the foregoing and other changes in form and detail may be made therein by one skilled in the art while still remaining within the spirit and scope of the invention.