Roller separators generally have a series of pairs of counter rotating cleaning rollers, ususally of rubber or other resiliently deformable material, to allow "pull-through" of stones and other trash whilst minimizing damage to tubers, wherein one of said rollers has a plain surface and the other has a helical projection extending therefrom. The helical projections extending from end to end of the rollers are formed and arranged to advance tubers along the rollers and to break up dirt clumps and other debris.

Separators of the kind described above have been known for a number of years e.g. from U.S. Patent No. 3473658 Bartlett and U.S. Patent No. 2618385 Silver for use both in mobile applications as on harvesters in the field or in stationary applications for cleaning a crop of tubers prior to storage.

The efficiency of such known machines is effectively controlled by the rate of roller rotation, the angle of

SUBSTITUTE SHEET

the helical projection thereon and the angle of inclination relative to the ground of the rollers and hence the effects of gravity on the crop being cleaned.

It will therefore be understood that a separator of the known kind in use in a field would be subject to variations in the inclination of the rollers both on uphill and downhill slopes with consequently significant effects on the efficiency of the separator.

Separators which can have the inclination of the rollers adjustable to suit traversal of the uphill or downhill slopes of a field are known from U.S. Patent No. 4471876 Stevenson, but these can only compensate for large general variations of roller inclination that may be experienced across a field. Constant manual and/or automatic adjustment of the roller inclination has been proposed but sufficient degree of angle variation has proved difficult to incorporate into separators effectively. Furthermore clods and stones on the rollers will tend to jump around and may not be fully separated from tubers, as well as tubers being possibly damaged by bouncing off rollers, stones and/or other tubers.

It is an object of the present invention to avoid of minimise one or more of the above disadvantages.

The present invention provides a separator suitable for use in separating tubers and the like from haulm, clods, weeds, stones and the like collected during harvesting which separator comprises a plurality of pairs of elongate counter-rotating separator or cleaning rollers and an overhead conveyor having a conveying run extending above said rollers from loading end portions towards discharge end portions thereof, for engagement with tubers or the like disposed on said rollers, in use of the separator, so as to impart drive thereto in a direction towards said discharge end portions whilst captively retaining said tubers or the like between said overhead conveyor and said counter-rotating rollers whereby in use of the device tubers may be conveyed along said rollers at various angles of inclination of said rollers during traversal of undulating terrain whilst being restrained against excessive movement, and at a generally constant rate of conveyance.

Thus with a separator of the present invention tubers may be separated and to a large extent have removed therefrom haulm, clods, weed etc. in an effective and economical manner and especially so when used in harvesting apparatus on undulating and/or rough terrain. Moreover, with the separator of the present invention the rate at which the potatoes traverse the

rollers of the cleaning table is made relatively independent of the angle of inclination (even where no provision at all is made for adjusting the angle of inclination of the cleaning table when traversing undulating terrain) , thereby minimising any problems e.g. pile ups, arising from variations in the traverse rate. In addition tuber damage is substantially reduced by substantially restraining the tubers against bouncing etc. even when traversing rough terrain. Furthermore the speed of the overhead conveyor may readily be varied to speed up or slow down the rate of passage of the tubers over the cleaning table rollers as required e.g. to cater for variations in tuber feed rate, relative volume/density of detritus etc.

Preferably said rollers have a generally cylindrical outer body having a resiliently deformable covering thereon formed and arranged to grip irregular angular and/or thin shapes or objects such as stones, haulm, weeds etc. and pull them downwardly between the rollers thereby separating them from the tubers.

Preferably at least one of said first and second rollers has a helical rib extending from a said loading end portion to a said discharge end portion thereof and is formed and arranged for positively advancing tubers coming into contact therewith from the said loading end

portion to the said discharge end portion, to a greater or lesser extent. It will be appreciated that the rate of movement of the tubers between said end portions will generally be largely dependent on the pitch of said helical rib and the rate of rotation of said rollers.

Preferably said plurality of pairs of rollers is mounted in a support framework, in a plane inclined slightly below the horizontal in a direction towards their discharge end portions with the axis of rotation of said rollers extending in the same direction as the movement of said tubers. The framework is desirably provided with level adjustment means formed and arranged to keep said rollers in said generally horizontal plane when the separator of the invention is crossing terrain which departs from the horizontal. Advantageously said level adjustment means may be formed and arranged for automatic operation to facilitate traversal of terrain with variable angles of slope without the need for repeated manual adjustment. It will be appreciated though that it is a particular advantage of the present invention that due to the substantially captive engagement of the tubers on the cleaning table rollers, it is possible to avoid the use of any level adjustment means entirely if desired, thereby simplifying construction and reducing manufacturing costs. Thus where no level adjustment is used the cleaning table may

be disposed generally horizontally. Alternatively, if desired, the cleaning table could be inclined downwardly (in the downstream direction) if required to reduce the drop down to a subsequent conveyor.

The overhead conveyor may be of any suitable form which can engage and impart drive to, tubers disposed on said rollers. Preferably said conveyor comprises an endless conveyor mounted on at least two return guides, and provided with suitable drive means. Conveniently the guides are in the form of guide rollers at least one of which is provided with a said drive means formed and arranged for driving said endless conveyor. The endless conveyor may be of any suitable form which can more or less positively engage the tubers for imparting drive thereto. Thus the conveyor may be in the form of an endless belt having a surface of resiliently deformable material, such as an open or closed cell foam polymeric material, e.g. a rubber sponge-like material, to prevent excessive movement of the tubers. The use of such a resiliently deformable material helps reduce damage to said tubers during separation still further.

In another form of conveyor an endless belt or chain has mounted thereon a plurality of spaced apart paddles or flights, or a multipicity of fingers or bristles, projecting downwardly into close proximity to said

separator rollers so as to generally define compartments in which tubers disposed on said rollers may be captively retained and thus carried forward therein as the conveyor advances.

It will be appreciated that whilst the overhead conveyor may conveniently be in the form of a single flexible endless conveyor elements extending along the separator rollers, it could alternatively be in the form of a series of element extending therealong e.g a series of generally cylindrical brushes all rotating in the same direction for successively sweeping the tubers along the separator rollers.

It will also be appreciated that the rate of flow of tubers over the rollers may be controlled by adjusting the speed of the drive means to said endless conveyor.

Furthermore the rate of tuber flow through the separator may be maintained at a generally constant rate irrespective of the slope or roughness of the terrain without the problems of backing up of tubers and blockage of the separator when the separator rollers are tilted upwardly (in the downstream direction) so that the tubers roll back and/or their flow rate is reduced.

Preferably the conveyor is mounted above the rollers in such a way that its height above the separator rollers

can be 'varied with the aid of suitable height adjustment means thereby to accommodate different sizes of tuber and to some extent control the variable transit time of tuber flow and the degree of separation.

Preferably the conveyor is provided with resilient biasing means formed and arranged for holding the conveying run of the conveyor down at a desired pre-determined height above the separator rollers whilst allowing transitory upward displacement thereof to pass over particularly large tubers, clods, stones or the like.

In another aspect of the present invention the belt assembly is mounted over the roller table in such a way that it can be readily adjusted in its height relative to the rollers to accommodate different sizes of crop and assist in controlling rate of crop flow and separation. The belt assembly is also mounted in such a way and is spring assisted to allow it to be adjusted to float lightly on the crop and also to float upwards to ride over large stones, clods or lumps of weed or haulm passing under it.

In a further aspect of the present invention provides a separating device comprising a frame with multiple pairs of contra-rotating, variable speed, spiral and plain

rollers of rubber or similar resilient deformable material arranged with their axis in direction of material flow and including a further pair of rollers mounted on a separate frame above and transverse to the aforementioned rollers, fitted with a belt having a surface of rubber or other similar resiliently deformable material over its surface and arranged to be driven a variable speeds in either direction.

Preferably the belt has a series of fingers or flights of rubber or similar resiliently deformable material attached to its outer surface.

Preferably the belt is suspended on a linkage connected to an adjustment mechanism allowing the belt to be raised or lowered relative to the separating rollers to vary the gap between the deformable fingers on the belt and the rollers.

Preferably the adjustable linkage carrying the belt assembly is arranged whereby the belt assembly can float upwards to allow irregular material to pass freely between the separating rollers and the finger belt.

Preferably said separating device has a series of transverse shafts with extending resiliently deformable finger wheels mounted along their length to operate in

place of said finger belt arrangement.

Preferably the complete assembly, including finger belt, pivoted at one end and the other end capable of being adjusted up or down either by hydraulic cylinder, electrically operated or hand operated screw to allow operating angle of rollers to be varied.

Preferably said separating device includes a variable flow control mechanism which controls flow of material over the separating rollers by variation of driven speed of the aforementioned flow control mechanism.

It will be appreciated that harvesting conditions in the field can vary very considerably, especially in relation to soil type, weather, moisture, haulm condition (state of decay etc.), crop size etc. This in turn will considerably influence the optimum dimensions of the various parts and their disposition. In practice it has been found that for harvesting tubers, the rollers should generally have an outside diameter of the order of 50 to 100, preferably from 75 to 90 mm, including where applicable any helical rib. The latter may conveniently have a depth of the order of 10 to 15 mm. In order to avoid excessive build up of mud on the rollers under adverse harvesting conditions, a scraper or doctor blade may conveniently be provided adjacent a

plain conveyor roller for scraping mud excess therefrom.

Where a pintle belt is used this conveniently has flexible fingers with a length of from 30 to 60, e.g. about 45 mm. with a diameter of from 3 to 8, e.g. about 5 mm, disposed at a pitch of around 8 to 20, e.g. about 12 mm. The spacing between the tips of the fingers and the conveyor roller outside surface is conveniently adjustable within a range of from 20 to 60, e.g. 25 to 40 mm.

Further preferred features and advantages of the present invention will appear from the following detailed description given by way of example of some preferred embodiments illustrated with reference to the accompanying drawings in which:- Fig. 1 is a side elevation of the separator of the invention; and

Fig. 2 is an end elevation of the discharge end of the separator in Fig. 1.

Fig. 1 shows a separator of the invention generally indicated by reference number 1. The separator 1 comprises a frame 2 on which are mounted six pairs of elongate counter-rotating cleaning rollers 4 via rotatable bearings 6. An overhead conveyor 5 is mounted above the rollers 4. A hydraulic motor 8 drives the rollers 4 such that the left hand roller 4a is rotated

clockwise and the right hand roller 4b rotated counter-clockwise (see Fig.2). One, only, of each pair of the rollers has a helical rib in order to assist conveying of the tubers over the rollers whilst avoiding an excessive gap between the main roller surfaces to minimise pulling through of tubers by the rollers along with the unwanted detritus. In the illustrated embodiment, the left hand roller 4a of each pair of rollers 4 has a right handed helical rib 10 extending therefrom. A supply conveyor 12 loads a mixture of potatoes 14 along with other trash including haulms 15, stones 16 onto a loading end portion 18 of the rollers 4. The rotating helical rib 10 of each pair of rollers 4 drives the potatoes 14 into a channel 17 defined by the rollers 4a, 4b (See Fig. 2) and drives them towards the overhead conveyor 5.

The overhead conveyor 5 comprises an endless belt conveyor 20 mounted around two return rollers 23, 24, the rearmost roller 24 being provided with a hydraulic motor 26 to drive said conveyor 5. The endless belt conveyor 20 has a series of spaced apart paddles 22 mounted thereon, each of the paddles 22 being made up of a multiplicity of flexible fingers 25 of resilient rubber material or the like and formed and arranged so as to engage without causing damage said potatoes 14. The paddles 22 drive the potatoes 14, haulm 15 and

stones 16 along the rollers 4 so as to be progressively separated with the trash being ejected downwardly through the separator roller pairs. Preferably the overhead endless belt conveyor is in the form of a pintle belt made up of a closely spaced array of flexible fingers 25 extending substantially across the whole belt as shown in the detail view. The fingers 25 are easily deformable to give way and bend around the tubers without damaging them whilst engaging them with sufficient force to apply to them a more or less positive driving force along the conveyors rollers 4. The overhead conveyor 5 is mounted to the separator frame 2 at a front pivot point 28 and a rear pivot point 30 on each spaced apart side 32, 34 of the frame 2 by a front suspension arm 36 and a rear suspension arm 37 which are interconnected side to side by shafts 38 across the separator 1. The front suspension arm 36 is connected via a front drop link 40 to the front end 41 of a beam 42. The rear suspension arm 37 is connected via a rear link 39 to the rear end 44 of said beam 42 which is mounted to the endless belt conveyor rollers 22, 24. The height of the conveyor 5 above the rollers 4 can be adjusted by an adjustment handle 46 having a threaded portion 47 which moves the position of the upper end 48 of the rear link 39 in a slotted link 50, bearing on a pin 52 so as to lift or lower the conveyor 5. Counter balance for the conveyor 5 is provided by a

helical coil spring 54 which is provided with an eye bolt 56 for adjustment purposes.

In more detail and with reference to Fig. 2, the counter rotating rollers 4a, 4b define a channel 17 in which the potatoes 14 are rotated, any stones 16 or haulm 15 being grabbed by opposed downwardly turning roller faces 4c, 4d, drawn through thereby and then ejected downwardly below the rollers 4a, 4b. The rollers 4 are covered with a layer of resiliently deformable material such as rubber foam, preferably provided with a protective outer skin e.g. of a plastics material in generally known manner, so that the potatoes 14 are not damaged as they pass over them.

The rate of passage of potatoes 14 and the effectiveness of the separation and cleaning thereof is generally related to their transit time in the separator which can be controlled by varying the speed of the conveyor 20, thereby permitting greater control over cleaning efficiency than was previously possible. In general shorter transit times will increase the rate of processing by the separator but possibly with some loss of cleaning or separating efficiency. In addition higher conveyor speeds may increase the risk of damage through 'scrubbing' of the tuber surfaces. In addition by keeping the distance between the conveyor belt 20 and

the roller 4 more or less closely similar to the size of potatoes passing therethrough, it is possible to minimise throwing around of the potatoes and thereby to minimise damage thereto.

it will be appreciated that the abovedescribed apparatus may be used with any generally rounded produce including various other root crops and other vegetables or fruit such as for example sugar beets, tomatoes, turnips, onions, certain types of larger carrots, and bulbs.