GB2187718A

GB2187718A - Controlling article feeding

Info

Publication number: GB2187718A
Application number: GB08705244A
Authority: GB
Inventors: Stephen Charles Barratt
Original assignee: Roneo Alcatel Ltd
Current assignee: Roneo Alcatel Ltd
Priority date: 1986-03-11
Filing date: 1987-03-06
Publication date: 1987-09-16
Also published as: GB2187718B; GB8705244D0; GB8605924D0

Abstract

Articles 19, 20, e.g. mail to be franked, are fed in partial overlapping relationship to a stacking position by a feed belt (13) controlled by a sensor 16, 17 located adjacent the receiving position 15 on the conveyor such that when an article is detected at the receiving position, the belt is driven whereas when the trailing edge of an item is sensed in the absence of the next item, the belt is halted until entry of the next item to the receiving position causes the belt drive to be restarted. The sensor mechanism may comprise an infra-red light source 16 and a photo-electric detector 17. <IMAGE>

Description

SPECIFICATION Feeding apparatus This invention relates to feeding apparatus and in particularto apparatus for receiving individual items to be fed and then feeding them in partial overlapping relationship.

In postal franking machines mail items are fed to the machine either by hand orfrom a hopper and, after passing through a printing station at which a franking impression is printed on the item, the item is ejected. In machines designed to handle large numbers of mail items it is common to provide a stacker to receive the mail items.Afeed belt carrying the items to the stacking station is controlled from a powerdriveofthefranking machine such thatthe mail items are received onthefeed beltin partial overlapping relationship. In order to control the feed belt, an electrical connection is provided between the stacker and the franking machine to carry control signals from the franking machine to the stacker.As a result a stacker can be used only with a franking machine designed to provide the required control signals.

It is desirable to be able to provide a stacker as a self contained module which operates totally inde pendently of the franking machine so that it may be sold independently and used with any franking machine buy a user.

A difficulty arises in controlling the drive ofthe feed belt of an independent device because the flow of items through a franking machine is not nec essarily constant. If the speed of the belt is uniform, when there is an interruption in the flow of mail items the next item will not overlap the previous item and this would lead to interference between these items and probably result in mis-stacking of the items.

According to the invention apparatus for feeding individual items in partial overlapping relationship includes a feed belt to receive the items at a receiving position; drive means energisableto drive the beltto carry the items from the receiving position; control means operableto energisethe drive means; sensing meansatthe receiving position responsiveto the passage of a trailing end of an item past the sensing means in the absence of a subsequent item to cause the control meanstode-energisesaiddrive means.

Preferably the control means is operative to en ergise the drive means for as long as the presence of an item is sensed by the sensing means and if desired the control means may maintain energisation of the drive means for a predetermined period after the trailing end of an item has been sensed bythesensing means.

A preferred sensing means includes a photo elec tricdetectorresponsiveto source of radiation which preferably is infra-red, the detector and the source being positioned such that a radiation path therebetween is interrupted by entry of an item into the receiving position.

A guide plate may extend adjacent and substanti- ally parallel to one edge ofthe belt, said guide plate being operative to engage and guide items carried by said beitfrom the receiving position.

A run ofthe belt extending from the receiving position preferably projects above a planar surface.

The source of radiation and the detector may be located in apertures in the guide plate and the planar surface.

Preferably the apparatus includes a stacking platform remote from the receiving position, said feed belt having a run extending from the receiving position to the stacking platform and said platform being inclined to the run ofthe feed belt.

The apparatus conveniently is constructed as a self contained moduleforusewith a machine operable to feed items seriatim to the receiving position.

Another aspect of the invention encompasses the combination of apparatus as hereinbefore defined with a machine operable to feed items seriatim to the receiving position of said apparatus.

An example of a machi ne with wh ich the appar- atus may be used is a mail item franking machine.

An embodiment of the invention will now be described byway of example with reference to the drawings in which Figure lisa view of a mail item feeder and stacker, Figure2is a diagram showing items being fed in overlapping relationship, Figure3isasimilardiagramshowingthefeeder stopped awaiting receipt of the next item to be fed and Figure 4 is a block diagram of an electrical circuit for controlling a motordriveforthefeeder.

Referring to Figure 1 of the drawings, a feeder stacker for mail items comprises a base enclosure 10 carrying a stacker platform 11 and a rear guide plate 12. The base enclosure 10 contains within it two pairs of roliers (not shown) around which pass two end- less feed belts. The upper runs 13 of the belts extend lengthwise of the enclosure 10 substantially parallel to the rear guide plate 12. The upper runs 13 ofthe belts project slightly above the upper surface 14 of the enclosure 10. An electric motor is disposed within the enclosure and iscoupledtoonepairof rollers, by for example a drive belt.When the motor isenergised by control means, the upper runs 13 of the drive belts travel from a mail item receiving position 15, adjacent one end ofthe feeder, toward the stacker platform 11. If desired, instead oftwo belts a single belt or more than two belts may be provided forfeeding the mail items.

A source 16 of infra-red radiation is positioned in an aperture in the rear guide plate 12 adjacentthe receiving position 15 and a photo electric detector 17 responsiveto infra-redenergy,butrelativelyinsen- sitiveto ambient light, is positioned in an aperture in the upper surface 14 of the enclosure adjacent the receiving position 15 such that it receives infra red radiation from the source 16. When a mail item 19,20 enters the receiving position 15, it interrupts the path of radiation between the source 16 and the detector 17 and thereby prevents the radiation being received by the detector. If desired the positions of the detector and the source of radiation may be interchanged.

The construction and operation ofthe control means will now be described. A block diagram is shown in Figure 4 to which reference is now made.

The infra-red detector 17 is connected to provide an input signal to a switching circuit 22 which provides a control signal to a power switching device 23. The power switching device may be a triac connected between the motor 24 and an AC power input 25. The switching circuit 22 operates at low DC voltage and receives powerfrom a lowvoltage power circuit 26.

In order to ensure electrical safety, it is preferred to provide an electro-optic isolator 27 in the connection between the switching circuit 22 and the power switching device 23. The above described arrangement utilises a motor 24 operating from a high voltageAC supply. In an alternative arrangement utilising a motor operating from a low DC voltage, a thyristor control led by the switching circuit is used to control energisation ofthe motorfrom the low voltage power circuit 26.

The operation of the control means is as follows.

When the path of radiation is interrupted by the entry of a mail item into the receiving position 15, the infrared detector ceases to receive infra-red radiation from the source 16 and this results in the switching circuit 22 generating a control signal to turn the power switch into a conducting state and thereby energise the motor 24. Thus the belts are driven by the motor and as the mail item lands on the belts it is carried toward the stacking platform 11. When the trailing end ofthe mail item passes the path of radiation and thus allows the detector to receive the radiation, the detector causes the switching circuit22 to turn the power switching device into a not conducting state thereby de-energising the motor 24 and stopping the belts.As a consequence the mail item is carried toward the stacking platform 11 and is then halted with its trailing end just beyond the detector 17, in a downstream direction. The position relative to the detector at which the item is haited may be varied by providing a variable time delay in the switching circuit 22 which operates to cause the energisation of the motorto be maintainedfora period determined by the variable time delay of circuit 22.

Operation ofthefeeder/stacker in conjunction with a machine 18 (see Figures 2 and 3) such as a postal franking machine which has an outfeed of items will now be explained. Mail items 20 are ejected seriatim in free flightfrom the machine 18 and fall into the belts 13. As the items enter the receiving position the radiation path is interrupted by the mail item and the motor is energised to drive the belts to carry the item toward the stacker platform. If the next item ejected from the machine 18 enters the receiving position 15 and hence interrupts the radiation path beforethe trailing end 21 of the previous item has passed the detector, sothatthe latter item 20 partially overlaps the earlier item 19 as illustrated in Figure 2, the radiation path continues to be interrupted and hence the control means continues to energise the motor without interruption. However if there is a substantial time interval between consecutive mail items being ejected from the machine 18, the trailing end 21 ofthe item 19 is carried past the detector priorto the next item 20 entering the receiving position 15 and interrupting the radiation path as is illustrated in Figure 3.As a result of the detection of the passage of the trailing end 21 of a mail item bythe detector 17 receiving infra-red radiation from the source 16 the control means de-energises the motor and thereby stops the belts 13. Thus wheneverthe duration ofthe time interval between ejection of consecutive items from the machine 18 is sufficiently long that the detector receives radiation from the source 16, the belts are stopped to awaitthe arrival of the next item. In this mannerthe items are always laid on the belt runs 13 in partial overlapping relationship. The belt runs 13 carry the items to the stacker platform and the leading edge of a first item slides up the platform.

Since subsequent items partially overlap preceding items the leading edge of each item slides up the preceding item and the items are thereby stacked against the platform 11.

The speed of linear travel of the belt runs 13 is generally chosen so that, with a normal continuous rate of ejection of items from the machine 18, the belts are driven continuously and the items overlap to a substantial extent. The time delay of the switching circuit 22 can be preset so that when the trailing end of an item passes clear of the infra-red radiation path and a later item has not yet arrived to interruptthe path, the control means causes the belts to be driven for a predetermined time to carry the trailing end of the item beyond the detector such that when the next succeeding item enters the receiving position it lands on the earlier item and overlaps the earlier item by a desired extent.

It will be appreciated that means such as a roller urged for example by gravity toward the belts is usually provided to press the mail items into frictional engagement with the feed belts to ensure reliable feeding of the items. This is not shown in the drawings but would be located downstream of the detector 16 at a position such that, in addition to pressing the mail items into engagement with the feed belts, it also acts to limit the extent of free flight of items ejected from the franking machine onto the feed belts.

Claims

1. Apparatus forfeeding individual items in partial overlapping relationship including a feed beltto receivetheitemsatareceiving position; drive means energisable to drive the belt to carry the items from the receiving position; control means operable to energisethe drive means; sensing means at the receiving position responsive to the passage of a trailing end of an item pastthe sensing means in the absence of a subsequent item to cause the control means to de-energisesaid drive means.

2. Apparatus as claimed in claim 1 wherein the control means is operative to energise the drive meansforas long as the presenceofan item is sensed bythesensing means.

3. Apparatus as claimed in claim 1 or2wherein the control means is operative to maintain energisation of the drive meansfora predetermined period afterthetrailing end of an item has been sensed by the sensing means.

4. Apparatus as claimed in claim 3 wherein the control means includes variable time delay means operative to determine the period after the trailing end of an item has been sensed during which energisation of the drive means is maintained.

5. Apparatus as claimed in any preceding claim wherein the sensing means includes a photo electric detector responsive to a source of radiation.

6. Apparatus as claimed in claim Swhereinthe detector is responsive to a source of infra-red radiation, the detector and the source being positioned such that a radiation path therebetween is interrupted by entry of an item into the receiving position.

7. Apparatus as claimed in claim 4,5 or 6 includ ingaguide plate extending adjacentandsubstanti- ally parallel to one edge ofthe belt, said guide plate being operativeto engage and guide items carried by said belt from the receiving position.

8. Apparatus as claimed in claim 7 wherein the belt has a run extending from the receiving position and projecting above a planarsurface.

9. Apparatus as claimed inclaim8whereinthe source of radiation is located in an aperture in said guide and the detector is located in an aperture in the planarsurface.

10. Apparatus as claimed in claim 8wherein the source of radiation is located in an aperture in the planar surface and the detector is located in an aperture in the guide plate.

11. Apparatus as claimed in any preceding claim including a stacking platform remote from the red ceiving position, said feed belt having a run extending from the receiving position to the stacking platform and said platform being inclined to the run of the feed belt.

12. Apparatus as claimed in any preceding claim constructed as a self contained module for use with a machine operable to feed items seriatim to thereceiving position.

13. Apparatus as claimed in any preceding claim including at least two feed belts.

14. Thecombination of apparatus as claimed in any preceding claim with a machine operable to feed items seriatim to the receiving position of said apparatus.

15. Thecombination as claimed in claim 14 wherein the machine is a mail item franking machine.

16. Apparatus for feeding individual items in partial overlapping relationship constructed and arranged to operate substantially as herein before described with reference to the drawing.