GB2140712A - Grader - Google Patents

Abstract

A grader 10 comprises two pairs of diverging object-supporting conveyor belts 12, 13 with one belt 12 of each pair supported from a common cross-beam 37 at the input end of the grader and from a common cross-beam 42 at the output end of the grader. Each of these two beams may be released by an associated quick-release mechanism 39 44 for movement relative to the support beam 36, 41 for the other belt 13 in each pair when the grader 10 is to be reset for different sizes of objects or grading requirements. Fruit (e.g. plums) to be graded may be passed through a stalk separator 71 comprising stop members 78, 79, which entrain the stalks, and contra-rotating rotors 85-88, which pull the fruit from the stalks. <IMAGE>

Description

SPECIFICATION Grader The present invention relates to graders and, in particular, but not exclusively, to graders for the sizing grading of fruit e.g. plums.

According to the present invention, a grader comprises two or more pairs of diverging object-supporting conveyor belts with one belt of each pair supported at at least one end of the grader by a common belt-locating means adapted for movement relative to the other belt of that pair.

Conveniently, the belt-locating means referred to above comprises one of two such belt-located means, one at one end and one at the other end of the grader.

The grader of the present invention has the advantage over existing fruit-grading equipment, for example, that it can readily be re-set to deal with different grading requirements and/or object sizes.

The demand from processors for plums for jam making or other forms of preservation has fallen significantly over recent years and plum growers have therefore had to rely to an increasing extent on the fresh fruit market where quality and presentation are of paramount importance. Apart from the EEC regulations which stipulate requirements for specific classes of plum, there are also regional preferences for presentation e.g. the retention of the wax-like 'bloom' on the surface of the fruit.

Thus in a preferred embodiment of the invention, intended principally for use with plums and other easily damaged fruit, the conveying belts are circular-section belts preferably made of polyurethane or other similarly resilient material.

The preferred form of belt-locating means will usually depend on the intended application of the grader. For example, in one embodiment of the invention, e.g. suitable as a plum grader for in-situ use in an orchard, the or each belt-locating means is provided by an appropriate number of pulleys supported from a common support member.

In an alternative embodiment, e.g. suitable as a plum grader for pack-house use, the or each belt-locating means is provided by a suitably profiled drum member.

Conveniently, in this latter embodiment, separation means are provided upstream of the conveyor belts to separate any plums, or other fruit, joined together by a stalk. The separation means conveniently comprises retention means and fruit-removal means for detaching fruit from any stalk retained by the retention means. In one such arrangement, for example, the retention means comprises one or more fixed stop members located in the path of the oncoming fruit and the fruitremoval means comprises one or more associated rotary devices operative to knock-off the plums or other fruit from any stalk wrapped about the stop member.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figures 1 and 2 are side and plan views of a grader for use in a plum orchard; Figures 3 and 4 are plan and side views of an input section of the grader not included in Figs. 1 and 2; Figures 5 and 6 are side and plan views of a grader for use in a pack-house; Figure 6a is a diagrammatic section; and Figures 7 and 8 are side and plan views, on an enlarged scale, of a separation unit for separating fruit and stalks upstream of the grading section.

Thus referring first to Figs. 1 to 4, a fruit grader 10, for use in a plum orchard, comprise two pairs of rearwardly moving conveyor belts 12, 13 diverging as shown in Fig. 2. In operation, fruit is deposited by the feed system of Figs. 3 and 4 on to the forward ends of these belts and is conveyed rearwardly until the separation of the belts has increased to a point where the fruit can pass between the belts to fall into an appropriate container (not shown) at one or other of the packing stations 15.

Clearly the discharge position for any particular fruit will depend upon the size of that fruit so that, provided the belts have been properly set up, the smallest fruit in any sample will tend to be discharged at the first of stations 15, medium-small and mediumlarge fruit will be discharged at the intermediate stations and the largest fruit at the rearmost station. To assist the accuracy of grading the belts can be driven at different speeds.

This causes the plums to rotate as they travel along so that they fall through on their minimum dimension as soon as possible. This feature is an advantage as the plums are not perfectly round.

As illustrated by Fig. 1, the conveyor belts 12, 1 3 each pass around for pulleys 17-20 of which pullleys 17, 18 support and locate the belts over the conveying run and pulleys 19, 20 support and locate the belts over their return run. Between pulleys 1 7 and 1 8 are guides 21. These support the belts from underneath so that they do not sag or move apart due to the weight of plums on them.

The belts are driven from the foremost of the bottom support pulleys 1 9 via first and second drive assemblies 22, 23. Assembly 23 is powered from a petrol engine 25 and also drives a fan 27 for an upwardly-extending bifurcated duct 29, which produces an upwardly-moving airstream effective to remove any stalks or leaf matter which may have been discharged onto the belts 12, 1 3 with the plums.

As may be seen from Fig. 2, the upper pulleys 17, 18 are mounted on associated stub axles 31-34 with stub axles 31 at the input end of the grader supported from a fixed U-section crossbeam 36 and stub axles 32 supported from an adjustable crossbeam 37 held in place in beam 36 by quick-release mechanisms 39. A similar arrangement is used at the rear end of the grader where reference numerals 41, 42 indicate the fixed and adjustable beams respectively and reference numeral 44 indicates the quick release mechanisms.

Misalignment of the conveyor belts 1 3 when the divergence and/or separation of the belts 12, 13 is varied to deal with different fruit size or grading requirements presents no problem because of the highly resilient nature of the belts which are preferably made of polyurethane or other similarly resilient material to help preserve the bloom on the plums. For the same reason, the belts are preferably of circular cross-section e.g. typically of 12.7 mm diameter.

The feed arrangement for the belts is shown in Figs. 3 and 4 and comprises a sorting table 46 from which unacceptable fruit is removed by hand before the moving floor 48 of the table discharges the fruit via chutes 50, 51 on to one or other of the belt pairs 12, 1 3.

The drive roller 53 for moving floor 48 is mounted coaxially with a sprocket wheel 55 (Fig. 1) driven through a chain and sprocket drive from the drive assembly 22 for the conveyor belts.

In the pack-house grader 60 of Figs. 5 to 8, the pulleys 17-20 of the first embodiment are replaced by grooved drums 62, 63, 64, 65 one conveying belt 1 3 of each pair 12, 1 3 being driven by the top drums 62, 63 and the other belts of those pairs being kept clear of these drums by rollers 67 and passing instead around lower drums 64, 65. As before the belts rest on guides 21 which are fixed in relation to their respective drums.

As before, the grader can readily be adjusted for different fruit sizes and grade requirements by having the top drums 62, 63 axially adjustable on operation of a screw mechanism 69. As before, the drum 63 is driven at a slightly different speed from drum 64 to give a rotating effect to the plums as they move along the belts.

Although basically very similar to the first embodiment in its mode of operation, the grader 60 of Figs. 5 to 8 varies from the first in its manner of dealing with the fruit once it has passed between the belts and in the presence of a stalk/fruit separator 71 upstream of the grading section.

Dealing first with the fruit collection aspect, it will be seen from Figs. 5 and 6 that once it has passed between the belts 1 2, 13, the fruit will fall on to one or other of two downwardly converging collection surfaces 73, 74. As best seem from Fig. 6a, surface 74 stops short of and discharges on to surface 73 which is thereafter provided with guides 76 to define a number of discharge chutes for the different grades of fruit to be collected.

Turning now to the separator 71, this comprises two rows of staggered stop members 78, 79 over which the stalks will wrap as the fruit moves down feed chute 81 towards belts 12, 13.

Fruit is removed from any stalks held in this way, by the arms 83 of the contra-rotating rotors 85-88, the hub portions of which are driven from a common drive chain 90 (Fig.

8). This latter is driven through a right-angled gear box 92.

The assembly is completed by an elevator 94 arranged to discharge fruit on to the upper end of feed chute 81 and by the various drives to the elevator 94, gear box 92 and drums 62-65. These drives are most clearly seen from Fig. 5 and comprise a chain driving between the motor 95 and the drum 64, and a chain driving from drum 64 to drum 63.

Typically, motor 95 will be a thyristor-controlled variable speed electric motor. A v-belt drives from the motor to a cross shaft 96. A v-belt from this shaft drives gearbox 92 and another belt drives the conveyor top roller 97.

The fan 98 provides an air blast across the staggered stop members 78 and 79 to remove any stalks and leaves.

The feed shute 81 also serves as a sorting table from which unacceptable fruit can be removed by hand.

Although only two embodiments have been described above, it will be understood that modifications of these embodiments are also possible without departing from the scope and spirit of the present invention e.g. by replacing features of one embodiment by associated features of the other embodiment.

Claims (9)

1. A grader comprising two or more pairs of diverging object-supporting conveyor belts with one belt of each pair supported at at least one end of the grader by a common beltlocating means adapted for movement relative to the other belt of that pair.

2. A grader as claimed in Claim 1 in which the belt-locating means comprises one of two such belt-locating means one at one end and one at the other end of the grader.

3. A grader as claimed in Claim 1 or Claim 2 in which the conveyor belts are made of polyurethane or other similarly resilient material.

4. A grader as claimed in Claim 1, Claim 2 or Claim 3 in which the or one of the beltlocating means is provided by an appropriate number of pulleys supported from a common support member.

5. A grader as claimed in Claim 1, Claim 2 or Claim 3 in which the or one of the belt locating means is provided by a suitably profiled drum member.

6. A grader as claimed in Claim 5 in which separation means are provided upstream of-the conveyor belts to separate any plums, or other fruit, joined together by a stalk.

7. A grader as claimed in Claim 6 in which the separation means comprises retention means and fruit-removal means for detaching fruit from any stalk retained by the retention means.

8. A grader as claimed in Claim 7 in which the retention means comprises one or more fixed stop members located in the path of the oncoming fruit and the fruit-removal means comprises one or more associated rotary devices operative to knock-off the plums or other fruit from any stalk wrapped about.

the stop member.

9. A grader substantially as hereinbefore described with reference to and/or as illustrated in Figs. 1 to 4 or Figs. 5 to 8 of the accompanying drawings.