GB2123782A

GB2123782A - Article feeding apparatus

Info

Publication number: GB2123782A
Application number: GB08220263A
Authority: GB
Inventors: Steven Arthur Bell
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-07-13
Filing date: 1982-07-13
Publication date: 1984-02-08

Abstract

Articles to be graded feed in a random phalanx down an incline (10). A vertically reciprocating frame carries upstanding bars (25, 26 and 27) which move up and down in gaps in the feed surface. The first bar (25) nudges articles one by one over a hump (12) to be nudged on by the second bar (24, 26) over a hump (14). At the top of their stroke the bars (26 and 27) close entrance and exit apertures (20, 21) to a light box (17, 18, 19) in which optical grading is effected. The articles are routed on a trajectory T2 or T3, depending upon whether a flap (21) is up or has been pulled down for the downstroke of the bars. <IMAGE>

Description

SPECIFICATION Article feeding apparatus The present invention relates to apparatus for feeding articles one by one through a workstation from an advancing random phalanx of the articles, such as may arise when the articles are fed gravitationally down a chute or edged forward en masse on a conveyor. Although the invention is not restricted to use with any particular kind of article it is particularly useful for feeding fruits or vegetables through a grading station, especially a station whereat optical inspection is carried out. One specific application is to the colour grading of tomatoes. A grower can sell as first class produce tomatoes of an intermediate stage of ripeness, i.e. of an intermediate degree of greenness. Tomatoes which are too red or too green are rejected.

At present colour grading is performed manually which represents a major labour cost. It is possible to grade tomatoes automatically by comparing the relative strengths of reflected red and green light but a need exists for apparatus which can feed the tomatoes rapidly and reliably through the workstation where light sensors are located.

The present invention provides apparatus for feeding articles one at a time through a workstation from an advancing random phalanx, comprising a feed surface, side walls defining at least one channel for articles to feed along the feed surface, a transverse gap in the feed surface, and a bar arranged to move up and down in the gap so as to nudge forward, on the upstroke, articles lodged in the gap.

A second, downstream bar is preferably arranged at the output end of the feed surface to move up and down with the first bar and to rise sufficiently on the upstroke to form a barrier which prevents articles moving out of the workstation; the articles move out on the downstroke.

To facilitate this there is preferably a humped formation between the bars. The first bar nudges articles over this formation; they then rest briefly at the workstation and move automatically off the hump when the barrier (second bar) is lowered.

The second bar can carry a movable flap for the or each channel movable between two positions to feed articles to two different output paths.

Preferably the flap moves between an upright position and a position rotated below horizontal and away from the second bar in the feed direction. With the flap upright it only just drops below the feed surface on the downstroke and an article trickles over the flap to fall nearly vertically.

When the flap is lowered the article drops on to the flap itself and bounces forwards, making it possible readily to achieve segregation from the vertically falling articles.

The first and second bars can both rise well above the feed surface to close entrance and exit openings of a light-proof housing when the articles are to be sensed optically. It may then be desirable to precede the first bar with another gap and bar so that if jams and ruptures of articles occur, it will be in a readily accessible region away from all optical devices.

It can be arranged also to reject undersize articles by allowing these to drop through a gap when the corresponding bar is at the bottom of its downstroke.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic side view of a tomato colour grader, Fig. 2 is a schematic plan view, Fig. 3 is a partial side view with bars lowered and a flap up, and Fig. 4 is a partial side view with bars lowered and a flap down.

Referring to Figs. 1 and 2 a feed surface comprises a downwardly sloped infeed table 10 followed by a first transverse gap 11, then a first humped section 12, then a second gap 13, and a second humped section 14. Tomatoes to be graded move in random phalanx down the table 10 between side walls 1 5 and are then segregated by partitions 1 6 forming individual tomato-size channels of which three are shown though more may be provided for increased throughput. The partitions are interrupted over the gaps 11 and 13.

Over the length of the second gap 13 and second humped section 14, the sidewalls extent up at 15a to form a light box with front and rear walls 17,18 and a top 19. The walls 17 and 18 extend only part-way down to the feed surface, leaving infeed and outfeed openings 20 and 21.

The light box houses one or more permanently illuminated lamps 22.

A horizontal frame formed by side members 23 and transverse member 24 carries three upstanding, transverse bars, namely first and second wide bars 25 and 26 aligned with gaps 11 and 13 and a third bar formed by a plate 27 carrying three hinged flaps 28 along its top edge, one for each channel. The flaps are shown up in Fig. 1, down in Fig. 2. The flaps are hinged at 29 and biased up by torsion springs (not shown).

They are pulled down by individual solenoids 30 connected to arms 31 projecting from the flaps.

The bar 26 and plate 27 carry photo-sensor units 32, each of which can consist of two phototransistors (for example) overlaid with red and green filters respectively and preferably also polarizing filters. The units 32 are provided individually for all channels.

The frame 23, 24 is reciprocated vertically by any convenient drive arrangement capable of achieving a reasonable rate, e.g. 120 reciprocations per minute, between a fully raised position (Fig. 1) and a fully lowered position (Figs. 3 and 4). Consider the situation of Fig. 3 and consider one channel only for simplicity. Tomatoes will lodge in the gaps 11 and 13 at locations I and II except that a newly entering undersize tomato will drop through the gap 11 on a first trajectory T1. When the frame rises the bars 25 and 26 (which have suitably rounded noses 33) will nudge the tomatoes at I and II over the humps 12 and 14 to positions III and IV respectively, where the tomatoes are arrested by the front faces of the bar 26 and plate 27.Position IV is the workstation whereat light is picked up by the units 32 in the raised position of Fig. 1. In this position the bar 26 and plate 27 plus flaps 28 shut off the openings 20,21 and exclude most ambient light.

When the bars drop again a new tomato moves into position I, the tomato at Ill drops into position II and the tomato at IV drops off the feed surface in a manner which can be selected as follows. The signals from the sensor units 32 are analysed (channel by channel) as outlined below to classify the tomatoes "pass" or "fail" which will be assumed to correspond to Figs. 3 and 4 respectively, although the converse could equally well be chosen.

For "pass" the flap 28 is left up as in Fig. 3 and the tomato cannot drop off until the bars are fully lowered. It therefore acquires littie forward momentum and drops through trajectory T2 which is not far off vertical. For "fail" the flap 28 is pulled down by its solenoid 30 and the tomato drops on to the flap itself. Because of the speed of reciprocation the tomato does not hit the flap until it is below the feed surface and rising again with high acceleration (say 29). The tomato is therefore bounced forward very markedly on trajectory T3. The three trajectories are well separated and allow the tomatoes to be segragated into containers or chutes for "undersize", "pass" and "fail'- respectively.

The signals from the phototransistors of the units 32 are preferably digitized and analyzed by a microprocessor dealing with ail channels in time division. The principle of operation is that a tomato is "pass" if the ratio of the red signal to the green signal lies within certain limits. Below the bottom limit or above the top limit the tomato is "fail". The red and green signals from the two units 32 for a channel may be combined before the ratio is formed or separate ratios may be calculated and logical tests applied such as both ratios must be within limits for "pass" or alternatively at least one ratio must be within limits for "pass". Particularly if the two ratios are separately formed it is possible to distinguish and "fail" blemished tomatoes.

The microprocessor can linearize the signals before forming ratios, can apply an ambient light offset to compensate for leakage into the light box and can automatically adjust to compensate for sensor changes (arising from aging, dirtying of filters, etc.) by sensing the signals when it is found by lack of reflected light that there has been misfeed and no tomato is there. The interior of the light box including surfaces of the bar 26, plate 27 and flaps 28 are preferably matt black.

Claims (Filed 25 Aug 82) 1. Apparatus for feeding articles one at a time through a workstation from an advancing random phalanx, comprising a feed surface, side walls defining at least one channel for articles to feed along the feed surface, a transverse gap in the feed surface, and a bar arranged to move up and down in the gap so as to nudge forward, on the upstroke, articles lodged in the gap.

2. Apparatus according to claim 1 ,further comprising a second, downstream bar arranged to move up and down with the first bar and to rise sufficiently on the upstroke to form a barrier which prevents articles moving out of the workstation.

3. Apparatus according to claim 2, wherein there is a humped formation between the two bars.

4. Apparatus according to claim 2 or 3, wherein the second bar carries movable flap for the or each channel, movable between two positions to feed articles to two different output paths.

5. Apparatus according to claim 4, wherein the flap moves between an upright position and a position rotated below horizontal and away from the second bar in the feed direction.

6. Apparatus according to any of claims 2 to 5, wherein the bars rise sufficiently above the feed surface to close entrance and exit openings of a light-proof housing.

7. Apparatus according to any of claims 1 to 6, wherein the first bar is preceded by another gap and bar.

8. Apparatus according to any of claims 1 to 7, wherein the or one of the bars open up a gap at the bottom of its downstroke for undersize articles to fall through.

9. Article feeding apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

10. A method of feeding articles through a workstation along at least one channel on a feed surface, wherein the articles are fed along the channel one by one into a transverse gap in the feed surface, at least some of the articles lodging in the gap, and wherein a bar moves up and down in the gap so as to nudge forward, on the upstroke, an article lodged in the gap.

11. A method according to claim 10, further comprising the step of moving a second, downstream bar up and down with the first bar, wherein the second bar is raised sufficiently on the upstroke to form a barrier which prevents articles moving out of the workstation.

12. A method according to claim 11 , wherein the first bar nudges articles lodged in the gap over a humped formation between the two bars.

13. A method according to claim 12, further comprising the step of selecting moving, between two positions, a movable flap carried by the second bar, whereby articles are selectively fed to two different output paths.

14. A method according to claim 13, wherein the flap is movable away from the first bar in the feed direction from an upright position to a position related below the horizontal.

1 5. A method according to any one of claims 11 to 14, further comprising the step of raising

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. (which have suitably rounded noses 33) will nudge the tomatoes at I and II over the humps 12 and 14 to positions III and IV respectively, where the tomatoes are arrested by the front faces of the bar 26 and plate 27. Position IV is the workstation whereat light is picked up by the units 32 in the raised position of Fig. 1. In this position the bar 26 and plate 27 plus flaps 28 shut off the openings 20,21 and exclude most ambient light. When the bars drop again a new tomato moves into position I, the tomato at Ill drops into position II and the tomato at IV drops off the feed surface in a manner which can be selected as follows. The signals from the sensor units 32 are analysed (channel by channel) as outlined below to classify the tomatoes "pass" or "fail" which will be assumed to correspond to Figs. 3 and 4 respectively, although the converse could equally well be chosen. For "pass" the flap 28 is left up as in Fig. 3 and the tomato cannot drop off until the bars are fully lowered. It therefore acquires littie forward momentum and drops through trajectory T2 which is not far off vertical. For "fail" the flap 28 is pulled down by its solenoid 30 and the tomato drops on to the flap itself. Because of the speed of reciprocation the tomato does not hit the flap until it is below the feed surface and rising again with high acceleration (say 29). The tomato is therefore bounced forward very markedly on trajectory T3. The three trajectories are well separated and allow the tomatoes to be segragated into containers or chutes for "undersize", "pass" and "fail'- respectively. The signals from the phototransistors of the units 32 are preferably digitized and analyzed by a microprocessor dealing with ail channels in time division. The principle of operation is that a tomato is "pass" if the ratio of the red signal to the green signal lies within certain limits. Below the bottom limit or above the top limit the tomato is "fail". The red and green signals from the two units 32 for a channel may be combined before the ratio is formed or separate ratios may be calculated and logical tests applied such as both ratios must be within limits for "pass" or alternatively at least one ratio must be within limits for "pass". Particularly if the two ratios are separately formed it is possible to distinguish and "fail" blemished tomatoes. The microprocessor can linearize the signals before forming ratios, can apply an ambient light offset to compensate for leakage into the light box and can automatically adjust to compensate for sensor changes (arising from aging, dirtying of filters, etc.) by sensing the signals when it is found by lack of reflected light that there has been misfeed and no tomato is there. The interior of the light box including surfaces of the bar 26, plate 27 and flaps 28 are preferably matt black. Claims (Filed 25 Aug 82)

1. Apparatus for feeding articles one at a time through a workstation from an advancing random phalanx, comprising a feed surface, side walls defining at least one channel for articles to feed along the feed surface, a transverse gap in the feed surface, and a bar arranged to move up and down in the gap so as to nudge forward, on the upstroke, articles lodged in the gap.

5. Apparatus according to claim 4, wherein the flap moves between an upright position and a position rotated below horizontal and away from the first bar in the feed direction.

the bars sufficiently above the feed surface to close entrance and exit openings of a light-proof housing.

16. A method according to any one of claims 10 to 15, further comprising the step of moving a third bar up and down with the first and second bars, in a gap upstream of the first gap.

17. A method according to any one of claims 10 to 16, wherein the or one of the bars is moved downwards on its downstroke sufficiently to allow undersize articles to fall through the corresponding gap.

1 8. A method of feeding articles, substantially as described hereinbefore.

New claims or amendments to claims filed on 7 June 1983 Superseded claims Claim 5 New or amended claims: