GB2067434A - Potato harvester - Google Patents

Abstract

A potato harvester has at least one upwardly inclined and rearwardly extending endless belt 1 formed of slats, and disposed above and substantially parallel thereto a second endless belt 10 having flaps 11 of about the same width as the slatted belt 1, the downwardly- directed flaps 11 having the same direction of transportation as the slatted belt 1 and touching said belt 1. The drive roll 12 for the overlying belt 10 is driven by a gear transmission wherein the gearing ratio can be adjusted such that the speed of the overlying belt 10 can be varied in relation to the speed of the slatted belt 1, to clean and sieve the potatoes. <IMAGE>

Description

SPECIFICATION Potato harvester The invention relates to a potato harvester having at least one upwardly inclined and rearwardlytravell- ing endless belt formed of slats, and disposed above and substantially parallel thereto, a second endless belt to which flaps of about the same width as the slat belt are attached, wherein the downwardlydirected flaps have the same direction of transportation as the slat belt and touch said belt.

A common type of potato harvester utilizes a sieving and transporting assembly consisting of an endless conveyor belt with transverse slat members.

Potatoes and accompanying contaminating material such as soil, lumps of earth, stones and plant remains enter the conveyor over the lower, forward part of the belt, either being fed directly from a plowshare mounted in front of the belt or from a preceding transporting means. In addition to the function of transporting the potatoes upwardly and to the rear, the main purpose of the slat belt is to sift out as much of the contaminating material as possible without damaging the potatoes. Such a belt with suitably spaced slats works very well for sieving particles smaller than the distance betwen the slats, but often a substantial portion of the contaminating material, i.e. lumps of earth, are of the same size as the potatoes or larger and thus cannot fall through the gaps between the slats. Many suggestions have been advanced for improving the effect of such a slatted belt.Most of the suggestions revolve around reducing or crushing the lumps down to a size which can be sifted out. For this purpose, devices have been suggested which give the sieving belt a vertical, oscillating motion, thereby producing a mutual grinding movement between the mass and the belt which reduces the size of the lumps. It has also been suggested to utilize fixed elastic fingers or flaps mounted above the slatted belt which subject the mass on the belt to pressure as it passes the fingers, while at the same time the mass becomes cleaned somewhat and its treatment time on the sieving belt is lengthened slightly.

The two known methods discussed above are generally recognised and much used, but a drawback common to both is that their action is effective over a relatively small proportion of the total surface of the slatted belt and thus has a limited effect.

Often, therefore, the pressure or oscillating motion necessary to obtain a useful effect must be set so high that a large percentage of the potatoes becomes seriously damaged. It is also a problem to adapt the intermediate settings correctly according to the prevailing conditions.

The second main function of the slatted belt, as mentioned above, is transportation of the potatoes.

The potatoes together with any residual contaminating material are to be conveyed to optional other sieving means and sorting means before being collected in suitable containers. For raising the potatoes to an appropriate height for sorting and subsequent transfer to a container, it is often desirable to use a slatted belt having the steepest possible inclination so that the belt will not have to be too long and costly. A slatted belt in which the slats lie Ivel in the same plane, however, is clearly limited as to its angle of inclination, since the poatoes will roll downwards, in the opposite direction of the desired direction of conveyance, if the belt travels too steeply upwards.

If the potatoes roll down the belt in this manner they will be damaged, and this is a great problem with some harvester embodiments, especially when used in sloping terrain and when the soil is light and easily sifted, such that stones and lumps of earth roll down the belt together with the potatoes and damage them.

To solve this problem, one may, for example, provide the belt with carrier means spaced at regular intervals. This however, makes it difficult to use lump-reducing means, and it is necessary to allow special clearances at the entry and exit ends of the belt. Another solution is to provide an overlying belt which moves parallel with the slat belt and prevents the potatoes from rolling down the belt of slats.

The latter solution, which is of interest in the present connection, is heretofore known only strictly as a conveyor, i.e., the overlying belt merely helps to raise the potatoes in height without providing any noticeable contribution to the sieving effect.

According to the present invention there is provided a potato harvester having at least one upwardly inclined and rearwardly extending endless belt formed of slats, and disposed above and substantially parallel thereto a second endless belt provided with flaps of the same or substantially the same width as the slat belt, the flaps on the bottom run of the second belt having the same direction of transportation as the upper run of the slatted belt and touching said slatted belt, said second belt being driven by a drive gear transmission wherein the gearing ratio can be adjusted such that the speed of the second belt can be varied relative to the speed of the slatted belt.

The term "flaps" as used in the present application should be understood in its widest sense, as the flaps could for instance also be formed of adjacent finger-like members which together form a flap-like member.

The pertinent range for the variable speed of the flap belt is from a maximum speed of nearly 100% of the slatted belt speed down to at least 20% of the slatted belt speed.

Potatoes, together with soil and other contaminating material, are introduced onto the slatted belt at the lower, forward end thereof. The mass is transported upwardly and rearwardly on the slats and will be engaged by the flaps or rows of fingers on the overlying second belt. If one wishes to subject the mass to the smallest possible lump-crushing effect, as may be the case when harvesting new potatoes (these are very easily damaged by even small mechanical loads, and the economic consequences of damage are proportionally high), or if the potatoes being harvested are being taken from easily sifted soil in which little contaminating material, especially lumps of earth, is present, the second belt speed can be set at the highest possible rate, i.e., at nearly the speed of the slatted belt.The flaps will then divide the mass into cell-like groups which direct the speed of transportation of the mass upwardly along the slatted belt, and in addition to the fact that the relative movement in relation to the slatted belt is minimal, the lump-crushing effect will also be minimal. The amount of material sifted out will be small, but the transportation will also occur with almost no relative movement of the potatoes so that they are subjected to as gentle a sieving action as possible.

If the greatest possible lump-crushing action is desired, as would be the case when harvesting middle- or late-season potatoes, and when the earth is sticky, moist or for other reasons is difficult to sift out, or when a large proportion of lumps of earth is present, it will be advantageous to set the second belt speed at or near the minimum. The relative speed of the potatoes, soil and other contaminating material in relation to the slatted belt will then be so great that one obtains a powerful lump-crushingl sieving treatment of each unit of volume, while at the same time this treatment will continue for a longer period of time owing to the slow transportation upwards and rearwards, which the second belt speed now also helps to determine.An additional powerful crushing effect can be obtained by pressing the second belt down towards the slatted belt by means of adjustable pressure rolls and/or slide rails.

The elastic flaps will then be pressed down with a certain force against the underlying slatted belt such that even the more solid clumps of earth that come between them will be able to be crushed to a greater degree.

A substantial advantage obtained with the invention in addition to the advantages discussed above is that with a flap belt with variable speed as suggested according to the invention, the angle of inclination of the belts can be permitted to be steeper than for conventional single sieve belts. In practice, this will mean that it will be possible to obtain such a high lifting height for the slatted belt that a special lifting means which is in use on many potato harvesters to raise the potatoes high enough can in many cases be eliminated.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawing, in which the single Figure shows a side elevation of the harvester according to the present invention and is strictly schematic in nature and serves merely to illustrate the principle of the invention, as the purely mechanical construction of the apparatus is considered to lie within the immediate competance of the skilled practitioner.

Shown in the drawing is an upwardly inclined and rearwardly extending endless belt 1 formed of slats.

The slatted belt 1 runs over end rolls 3 and support rolls, and the upper end roll 3 is formed as a drive roll.

Arranged above the slatted belt 1 is a belt 10 provided with flexible flaps 11. The flaps 11 have approximately the same width as the slatted belt 1 and the downwardly-directed flaps 11 have the same direction of transportation as the slatted belt 1 and touch the upper run of the underlying slatted belt 1.

The flap belt 10 travels over end rolls 12 and support rolls and the upper end roll 12 is formed as a drive roll. The drive means for the drive roll 12 mass comprises a gearing mechanism (not shown) whereby one can select different drive speeds for the drive roll 12 in relation to the drive roll 3, either in fixed gearing steps or with non-graduated variation being possible. In an embodiment the actual variation range will give the flap belt 10 a maximum speed of nearly 100% of the speed of the slatted belt 1 and a minimum speed of 20% of the speed of the slatted belts.

Potatoes, with soil and other material, are introduced onto the lower end oftheslatted belt 1 and the mass is transported upwardly on the slatted belt 1 and will come into engagement with the flaps 11.

The flaps 11, as mentioned previously, can be formed in many ways, and may for instance be formed of rows of fingers. In the accompanyiny drawing, the flaps 11 are shown positioned perpendicularly on the flap belt 10, but they can also be backwardly inclined in relation to the direction of movement of the belt 10.

To increase the crushing effect, it is advantageous to be able to press the lower run of the flap belt 10 down towards the slatted belt 1. For this purpose, adjustable pressure rolls 17 are provided. Also indicated are slide rails 18 which are adjustable and can be used to press the flap belt 10 down toward the slatted belt 1. The pressure rolls 17 and slide rails 18 can be utilized separately or in combination.

Claims (8)

1. A potato harvester having at least one upwardly inclined and rearwardly extending endless belt formed of slats, and disposed above and substantially parallel thereto a second endless belt provided with flaps of the same or substantially the same width as the slat belt, the flaps on the bottom run of the second belt having the same direction of transportation as the upper run of the slatted belt and touching said slatted belt, said second belt being driven by a drive gear transmission wherein the gearing ratio can be adjusted such that the speed of the second belt can be varied relative to the speed of the slatted belt.

2. A potato harvester as claimed in claim 1, in which the highest gearing ratio drives the second belt at the same speed or substantially the same speed as the slatted belt and the lowest gearing ratio drives the second belt at least 20% of the speed of the slatted belt.

3. A potato harvester as claimed in Claim 1 or Claim 2, in which the transmission comprises a plurality of intermediate gearing steps or has nongraduated gearing variation.

4. A potato harvester as claimed in any preceding claim, in which the flaps are formed byrows of elastic finger members.

5. A potato harvester as claimed in any preceding claim, in which the flaps extend at right-angles relative to the belt or are backwardly inclined up to 45C relative to the direction of movement of said second belt.

6. A potato harvester as claimed in any preceding claim, in which the flaps can be adjusted to contact with pressure the underlying run of the slated belt by one or more adjustable rollers and/or guide rails pressing the bottom run of the second belt towards the slatted belt.

7. A potato harvester as claimed in any preceding claim, in which the flaps are between 5 and 25 cm in depth.

8. A potato harvester substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.