GB2062566A - Improvements in or relating to the sorting of articles - Google Patents

Abstract

A feeding device for feeding articles to a conveyor 40 of a conveying system which has a plurality of discharge stations at which articles carried by the conveyor can be discharged comprises a sorting surface 30 to which articles to be sorted are fed by a pair of conveyors 12, 14. A rotatable roller 42 is positioned between the sorting surface 30 and the conveyor 40. In use an operator 32, 33 takes an article from one of the conveyors 12, 14, keys a destination code on the keyboard 34, 35, and places the article on the surface 30 against the roller 42. The roller 42 urges the article onto the conveyor 40. After the article has passed over the roller 42, drive to the roller is interrupted for a given time to allow sufficient spacing between that article and the next article placed on the surface 30. When the roller is not rotating it acts as a barrier against articles being fed to the conveyor 40. <IMAGE>

Description

SPECIFICATION Improvements in or relating to the sorting of articles This invention relates to a feeding device for feeding articles to a conveyor of a conveying system which has a plurality of discharge stations at which articles carried by the conveyor can be discharged.

Conveying systems are known which are used to sort articles, such as post parcels, according to their destination. The conveying system has a feeding device for feeding articles onto a main conveyor. The main conveyor has discharge stations located at intervals along its length. In one form of conveyor associated with each discharge station there is a diverter which is operable to move into the path of an article travelling along the conveyor to divert the article to the discharge station. In another form of conveyor known as the tilted belt type, associated with each discharge station is a gate which can be opened to allow the article to slide off the belt to the discharge station. Code setting means are provided at the feeding device by means of which an operator can feed into a control unit a code indicative of the destination of the article.The control unit is operative to cause actuation of the appropriate diverter or gate a predetermined time after the article is fed onto the main conveyor. The predetermined time is dependent upon the distance between the feeding device and the particular discharge station, the arrangement being such that the diverter or gate is actuated as the article approaches.

Investigations carried out on a parcel sorting machine have shown that for a given speed of operation of the conveyor, there is minimum spacing between articles on the conveyor for correct operation of the machine, this spacing being dependent upon the length of a given article.

The present invention is concerned with a feeding device which enables articles to be fed to the conveyor with the correct spacing.

According to the present invention there is provided a feeding device for feeding articles to a conveyor of a conveying system which has a plurality of discharge stations at which articles carried by the conveyor can be discharged, said feeding device comprising conveying means for delivering articles from a source to a position adjacent a sorting surface, said sorting surface being disposed between the conveying means and the conveyor of the conveying system, code setting means disposed at or adjacent said sorting surface for enabling a code indicative of the destination of an article to be fed into a control unit, a rotatable roller disposed between said sorting surface and said conveyor and arranged such that when it is rotating it is operative to urge an article placed against it from said sorting surface to said conveyor, and drive means for rotating said roller, said control unit being operative to cause drive to the roller to be interrupted for a predetermined period after an article has been fed to the conveyor.

The conveying means may comprise a pair of conveyors located side by side. The articles may be fed to said pair of conveyors via a chute and an inclined surface. The inclined surface may have a central ridge arranged to divert articles received from said chute towards one or other of said pair of conveyors. The chute may be mounted such that its mouth can be positioned centrally of the inclined surface or towards one or other side of the inclined surface.

A light source and associated photoelectric detector may be provided at the end of each of said pair of conveyors adjacent the sorting surface, each photoelectric detector being connected to said control unit and the arrangement being such that when the light beam from a source is interrupted by an article on a conveyor, drive to that conveyor is interrupted.

A light source and associated photoelectric detector may be provided for each side of said inclined surface, each photoelectric detector being connected to said control unit, and said control unit providing signals for energising means for supplying articles from said source. In one arrangement a light source and associated photoelectric detector is provided towards the upper end and lower end of each side of the inclined surface, each photoelectric detector being connected to the control unit and the control unit being arranged to control the position of said chute in accordance with the distribution of articles on said inclined surface.

Said sorting surface may be in the shape of a trapezium with two inclined edges converging toward the roller, the shorter parallel edge in juxtaposition with and parallel to said roller, and the longer parallel edge in juxtaposition with the end of said pair of conveyors. Code setting means are preferably provided one adjacent each inclined edge.

The roller is preferably positioned with its axis horizontal and so that the highest point on its surface is slightly above the sorting surface. The surface of the roller is preferably a high friction material.

A further light source and associated photoelectric detector may be provided above said roller for sensing articles fed to the conveyor, the photoelectric detector being coupled to said control unit. The control unit may be operable to count pulses for the period during which an article interrupts the light beam from said source and to provide a signal for interrupting drive to said roller for a predetermined period which is dependent upon said pulse count.

The invention will be described now by way of example only with particular reference to the accompanying drawings. In the drawings: Figure 1 is a perspective view of a feeding device for a parcel sorting machine; Figure 2 is a plan view of the feeding device; Figure 3 shows a keyboard used with the feeding device, and Figures 4 to 6 are block schematic diagrams of the electronic control circuitry associated with the feeding device and parcel sorting machine.

A feeding device for a parcel sorting machine comprises a ridged glacis 10 which slopes down from a conveyor 11 to a pair of adjacent endless conveyors 12, 14. The glacis 10 has a ridged floor formed by a pair of planar portions 16, 17 which slope away from a central apex 18 to opposite facing side panels 20, 21 which form part of the side wall of the feed device. Each side wall 20, 21 supports a pair of light sources 22, 23, 24, 25 located one towards the upper end of the glacis and one towards the lower end. Each light source is arranged to direct a light beam towards an associated photoelectric detector 26, 27, 28, 29 located adjacent the apex of the ridge.

Each conveyor 12, 14 is an endless conveyor which extends horizontally away from the lower end of the glacis to a sorting table 30 which, in plan, is trapezium shaped. Operator positions 32, 33 are provided on opposite sides of the table 30 and at each operator position there is provided a keyboard 34, 35. A detailed plan view of each keyboard is given in Figure 3. A pair of light sources 36, 37 are located on opposite sides of the conveyors 12 and 14 adjacent the sorting table 30. Each light source is arranged to direct a light beam towards a photoelectric detector 39 disposed at a position in between the conveyors 12 and 14.

A tilted belt parcel sorting machine conveyor 40 extends away from the table 30 and intermediate the conveyor 40 and the table 30 there is provided a roller 42 whose axis is disposed horizontal and perpendicular to the direction of movement of the conveyor 40. The roller 42 is intermittently drivable by way of a motor driven clutch/brake unit via pulley wheels and a toothed belt. The clutch/brake unit is controlled electronically as will be described. The highest point on the circumference of the roller is arranged such that it is a predetermined height above the surface of the table 30. For sorting parcels this height is typically 0.5 inches.

The roller 42 comprises a solid steel shaft which is located at its ends in needle bearings. The surface of the roller is covered with a high friction material such as that known as Habasit Amcoslip.

The function of the roller 42 is to aid transfer of a parcel from the table 30 to the belt of the conveyor 40 and also to impede transfer of a subsequent parcel until the preceding parcel has travelled a required distance along the belt.

A light source 45 is located at one side of the conveyor 40 a short distance from the roller 42.

the light source 45 is arranged to direct a light beam across the conveyor 40 towards a photoelectric detector 46. A further light source 47 is disposed a further distance along the conveyor 40 and is arranged to direct a light beam across the conveyor towards a photoelectric detector 48. In addition there is a light source and associated detector (not shown) at opposite ends of the roller 42 arranged to detect parcels passing over the crest of the roller.

The tilted belt parcel sorting machine conveyor 40, only a part of which is illustrated in Figures 1 and 2, has a number of discharge points located at intervals along its length. At each discharge point there is a gate which can be opened to allow a parcel moving along the conveyor to slide off the belt to the discharge station. Each gate can be controlled from an electronic control unit in accordance with information fed in from the keyboard 34. The arrangement is such that a particular gate is actuated a predetermined time after the parcel has been placed onto the conveyor 40. This predetermined time is dependent upon the distance between the beam from light source 47 and the relevant gate.

The feeding device also has an electronic control unit which receives signals from the keyboards 34, 35 and from the photoelectric detectors 26,27,28, 29, 39,46,48 and the detector adjacent the roller 42, and controls operation of the feeding device on the basis of these signals.

In operation parcels to be sorted are fed from a primary store to the glacis 10 by the conveyor 11.

The riged nature of the glacis 10 tends to divide the stream of parcels into two, one stream being fed to the conveyor 12 and the other stream to the conveyor 14. The conveyors 12 and 14 deliver the parcels to positions adjacent the operators 32, 33.

When a parcel is at such a position the light beam from the light source 36 or 37 is broken and this causes the respective conveyor 12, 14 to stop so that parcels do not pile up at the operator position.

Whenever, the beams of light from the light sources 22 and 24 are permanently broken by parcels the conveyor 11 is also stopped to prevent a build-up of parcels.

An operator takes a parcel for sorting from the end of the respective conveyor 12, 14, reads the address on the parcel, and presses an appropriate button or buttons on the keyboard 34 or 35 which causes a destination code to be written into a memory in the electronic control unit of the device. The parcel which he has removed is replaced by the action of the respective conveyor 12 or 14 moving forward until the next parcel breaks the light beam from one of the light sources 36 or 37.

After the operator has keyed in the relevant destination code he places the parcel on the table 30 against the roller 42. Normally this roller is rotating and because of its high friction surface and speed of rotation it tends to grab the parcel and move it forward onto the tilted belt parcel sorting machine conveyor 40. As the parcel moves forward it breaks the beam of light from the light source which directs a beam of light along the crest of the roller. This is sensed by the associated detector which causes a counter in the electronic unit to count pulses for the period of time during which the beam is broken. The number of pulses counted is representative of the length of the parcel. When the detector senses the trailing edge of the parcel the electronic control causes rotation of the roller to stop for a given time.This time is dependent upon the length of the parcel as represented by the pulse count which has just taken place. Whilst the roller is not being driven it acts as a barrier against a subsequent parcel being fed to the conveyor 40. The predetermined time is selected to ensure that a sufficient minimum spacing is obtained between parcels on the tilted belt conveyor 40 for correct operation of the gates to occur. Drive to the roller 42 automatically starts after the predetermined time so that the next parcel can be presented to the conveyor.

Efficient operation of the feeding device depends upon the operators 32 and 33 interleaving their actions. If correct operation is occurring it should not happen that both operators attempt to key in a destination code at the same time. In normal operation an operator only keys in a code when a "code now" lamp (see Figure 3) is illuminated on his keyboard. If the operation of one of the keyboards should happen to coincide with that of the other, the electronic control unit determined which keyboard was keyed first and accepts that code. A "code not accepted" lamp (see Figure 3) on the other keyboard is illuminated and that operator has to key again when his "code now" lamp is re-illuminated.

The light source and associated detector 48 are provided to sense passage of a parcel and cause the transfer of the destination code associated with that parcel from the electronic control of the feeding device to the electronic control of the parcel sorting machine so that the appropriate gate can be opened at the correct time.

In Figure 1 the glacis 10 is shown as being fed by a conveyor 11. An alternative and preferred arrangement is to provide a chute which is pivotable in a horizontal plane so that it can be arranged to direct parcels towards the centre of the glacis 10 or to either side of it. The position of the chute is controlled in accordance with the quantity of parcels on the glacis 10 and their relative distribution. For example if one side of the glacis is free of parcels this is sensed by the lower photoelectric detector 27 or 29 which causes the chute to be pivoted towards that side so that parcels are fed solely to that side. Similarly if parcels are evenly distributed on the glacis 10 and conveyors 12, 14, the chute is directed to deliver parcels centrally so that they divide into two approximately equal streams.If throughput of parcels is such that only one operator is needed the chute can be directed to permanently deliver parcels only to one side of the glacis, namely, that side associated with the operator.

It will be appreciated that the present feeding device provides each operator independently with a continuous flow of parcels. When a parcel is removed by an operator it is automatically replaced from a single layer of parcels on a conveyor, which in turn receives a controlled feed via the glacis 10 and the pivotable chute.

Referrring now to Figure 4 each keyboard which is represented at 70 and 71 is connected to a keyboard control printed circuit board 72 in the electronic control unit and also to a printed circuit board 73 which contains a number of control timers. When a keyboard operator keys in a destination code a signal is applied to one of the address code inputs 74, 75. If the code is accepted, the keyboard control circuit 72 produces an output on line 76 which is fed to the control circuit for the parcel sorting machine.

Outputs are also produced on lines 77 which are fed to the circuit board 73 for the control of timers on that board. The circuit board 73 has an input 78 from the photoelectric detector 48 and depending upon the state of that input the circuit board 73 produces an output on line 79 for synchronising the transfer of information relevant to a parcel being sorted to the parcel sorting machine control circuit. The circuit board 73 also has an input on line 80 from the photoelectric detector 46. Whenever the signal on this line is indicative of the sensing of the leading edge of a parcel being fed onto the conveyor 40 the circuit 73 produces an output signal which is fed to the keyboard control information inputs 82 to cause re-illumination of the "code now" lamps on the keyboard which are extinguished as soon as a code is keyed in on one of the keyboards.The circuit board 73 also includes a timer associated with each of the conveyors 12, 14. These timers are arranged to count whenever no parcels are being sorted from either or both conveyors. The arrangement is such that if either counter counts uninterruptedly for a period of 4+ minutes a signal is produced which causes the associated conveyor to stop. These signals appear on lines 82, 83.

There is also a timer which is activated on insertion of a destination code and deactivated by a signal from the detector 46 whenever the detector detects the leading edge of a parcel. The arrangement is such that if that counter counts for an uninterrupted period of 30 seconds the keyboard is freed for keying in a further code.

If when a code is keyed into either keyboard 70 or 71 it is not accepted, an output is produced on one or other of the lines 85, 86 and fed to the relevant keyboard to illuminate the "code not accepted" lamp.

Figure 5 shows a block diagram of the roller control circuit. This circuit includes a pulse generator 90 which produces pulses at the rate of 144 Hz. These pulses are applied to one input of a roller control printed circuit board 92. The circuit 92 receives an input on line 93 from the detector associated with the roller 42 and also inputs on lines 94, 95 indicative of the state of the two parcel presentation conveyors 12, 14. Whenever the detector detects a parcel the circuit board 92 counts the pulses from the generator 90. The number of pulses counted represents the length of the parcel and the circuit board 92 produces an appropriate output signal on line 98 which is applied to the clutch/brake printed circuit board 99 to cause the drive to the roller 42 to stop for a predetermined time. The predetermined period of time has been described above. The circuit board 99 also has an input line 100 which receives a signal from a further photoelectric detector associated with a light source adjacent the roller.

This detector is arranged to sense the presence of foreign matter and to generate a signal for stopping the roller whenever such material is sensed. There is also a third input 101 which can be generated from an emergency stop button to stop the roller in an emergency.

Figure 6 shows schematically the power supply control. The power supply control has a printed circuit board 106 which has six inputs. The first two inputs 107, 108 are signals indicative of the occupancy on the two presentation conveyors 12, 14. Inputs 110, 111 are connected to the lower detectors 29, 27 on the glacis 10 and inputs 112, 114 are connected to the upper detectors 28, 26 on the glacis. The circuit board 106 has four outputs. An output 11 5 is connected to the control for the drive to the primary parcel store.

Outputs 117, 118 and 119 are connected to a circuit which controls the position of the pivotable chute which feed the glacis 10.

The feed from the primary store is arranged such that the parcels are fed in batches of 1 5 to 20 parcels. The drive to the primary store feed operates under the control of a timer in the circuit board 106. This timer causes the drive to operate for a time sufficient to deliver 1 5 to 20 parcels. If after a batch is delivered the detectors still sense that more parcels are required the primary feed can be energised again to deliver a further batch.

This arrangement provides a controlled feed of parcels to the conveyors 12, 14 and prevents large piles of parcels building up on these conveyors.

The outputs of the lower detectors 27,29 are used to control the primary feed. The outputs of the upper detectors 26,28 are used to determine the position of the pivotable chute.

Manually operable coding means in the form of keyboards 34, 35 have been described. It will be appreciated that other forms of coding means can be employed. For example a voice recognition device responsive to an operators voice can be used. Alternatively an optical reader arranged to read the address on a parcel may be used.

Claims (14)

1. A feeding device for feeding articles to a conveyor of a conveying system which has a plurality of discharge stations at which articles carried by the conveyor can be discharged, said feeding device comprising conveying means for delivering articles from a source to a position adjacent a sorting surface, said sorting surface being disposed between the conveying means and the conveyor of the conveying system, code setting means disposed at or adjacent said sorting surface for enabling a code indicative of the destination of an article to be fed into a control unit, a rotatable roller disposed between said sorting surface and said conveyor and arranged such that when it is rotating it is operative to urge an article placed against it from said sorting surface to said conveyor, and drive means for rotating said roller, said control unit being operative to cause drive to the roller to be interrupted for a predetermined period after an article has been fed to the conveyor.

2. A feeding device as claimed in claim 1 wherein the conveying means comprises a pair of conveyors located side by side.

3. A feeding device as claimed in claim 2 wherein the articles are fed to said pair of conveyors via a chute and an inclined surface.

4. A feeding device as claimed in claim 3 wherein the inclined surface has a central ridge arranged to divert articles received from said chute towards one or other of said pair of conveyors.

5. A feeding device as claimed in claim 4 wherein the chute is mounted such that its mouth can be positioned centrally of the inclined surface or towards one or other side of the inclined surface.

6. A feeding device as claimed in any one of claims 2 to 5 including a light source and associated photoelectric detector provided at the end of each of said pair of conveyors adjacent the sorting surface, each photoelectric detector being connected to said control unit and the arrangement being such that when the light beam from a source is interrupted by an article on a conveyor, drive to that conveyor is interrupted.

7. A feeding device as claimed in claim 3 wherein a light source and associated photoelectric detector are provided for each side of said inclined surface, each photoelectric detector being connected to said control unit, and said control unit providing signals for energising means for supplying articles from said source.

8. A feeding device as claimed in claim 7 including a light source and associated photoelectric detector provided towards the upper end and lower end of each side of the inclined surface, each photoelectric detector being connected to the control unit and the control unit being arranged to control the position of said chute in accordance with the distribution of articles on said inclined surface.

9. A feeding device as claimed in any preceding claim wherein said sorting surface is in the shape of a trapezium with two inclined edges converging toward the roller, the shorter parallel edge in juxtaposition with and parallel to said roller, and the longer parallel edge in juxtaposition with the end of said pair of conveyors.

1 Q. A feeding device as claimed in claim 9 wherein code setting means are provided one adjacent each inclined edge.

11. A feeding device as claimed in any preceding claim wherein the roller is positioned with its axis horizontal and so that the highest point on its surface is slightly above the sorting surface.

12. A feeding device as claimed in any preceding claim including a further light source and associated photoelectric detector provided above said roller for sensing articles fed to the conveyor, the photoelectric detector being coupled to said control unit.

13. A feeding device as claimed in claim 12 wherein the control unit is operable to count pulses for the period during which an article interrupts the light beam from said source and to provide a signal for interrupting drive to said roller for a predetermined period which is dependent upon said pulse count.

14. A feeding device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.