ROOT CROP TOPPING ASSEMBLY

Abstract: A root crop harvester 8 (Figure 2) includes a preliminary topping device 13 followed by a topping assembly 11. Assembly 11 comprises a transversely disposed rotary device 18 including a number of skewed crown-engaging cutter bars 108 for removing skin from the crowns of crop partially topped by device 13. The topping assembly 11 is followed by a lifting device 12 for the topped crop. In alternative embodiments, the skewed straight edged cutter bars 108 are replaced by less skewed or axially parallel cutter bars having their cutter edges shaped so as in operation of the device to give the same effect as bars 108.

Description: ROOT CROP TOPPING ASSEMBLY The present invention relates to a root crop topping assembly and to root crop harvesters incorporating said assembly. According to the present invention a root crop topping assembly adapted for translational movement over soil containing a row of root crop comprises a rotary device including a number of skewed and/or shaped cutter bars symmetrically disposed about the rotation axis of the device and adapted on rotation of the device to sweep out a generally cylindrical shape having a concave wall portion designed to engage the crop in situ to remove surface material from the exposed crowns of the crop and leave on each crown a generally domed residue. Normally there will be six or more said bars, values of eight, or better, ten or more, currently being preferred. The invention also includes a rotary device for use in such an assembly. Conveniently, the rotation axis of the device is inclined at an an angle of not more than 45 to said translational movement. Conveniently, the rotation axis of the device is substantially transverse to said translational movement. Conveniently, the cutter bars are provided by substantially straight-edged bars skewed at between 300 and 600 to an imaginary reference plane lying perpendicular to the rotation axis of the device. Conveniently, in this last case, as with all the other embodiments and modifications having the cutter bars skewed, the cutter bars are preferably twisted so as at all points to have the major cross-sectional dimension of each cutter bar radially diposed in the device. Skew angles of about 450 are generally preferred. In alternative embodiments, the cutter bars lie substantially parallel to the rotation axis of the device and have their cutting edges shaped so as on rotation of the device to lie on said concave wall portion. In other alternative embodiments, the cutter bars are skewed and the cutting edges of the bars are shaped so as on rotation of the device to lie on said concave wall portion. Conveniently, the cutter bars are mounted between two circular end plates of the device and, although the number of bars may vary with different designs, a typical end plate diameter would be around 300 mm. Conveniently, the assembly includes a crown-sensing disc. As compared with the various brush arrangements of UKPA 8118581, the rotary devices of the present invention are likely to be cheaper to manufacture and the wearing surfaces provided by the bars and, if present, the end plates, can easily be "made good" by anyone reasonably proficient in the use of welding equipment. If desired, the bars could also be removable to enable a worn bar to be replaced. Typical root crops for which the assembly is suited include sugar beet and other root crops in which the greater part is below the surface, e.g. parsnips and some fodder beet varieties. In the case of sugar beet, for example, the assembly can be used to remove the green outer layer of a few millimetres thick, typically 3 to 5 mm, Which covers the interior part of the sugar beet crown suitable for processing to produce juice for sugar refining. The invention also includes a root crop harvester incorporating a topping assembly according to the present invention, preferably one mounted on the frame of the harvester by means of a leading arm arrangement adapted to urge the assembly into the desired optimum crop-topping relationship. Conveniently, but not necessarily, the root crop may be partially topped prior to engagement by the assembly of the present invention, e.g. by removing the bulk of the foliage with a preliminary topping device. In the preferred arrangement, this device-#ill sever the crown at a significantly higher level than is conventional for root crop harvesting. Typically, therefore, this device should not remove more than the top 10 mm of the crown and preferably not more than the top 7 mm (values in the range 2 to 5 mm being preferred). There may also be occasions where it is desirable or even necessary to lift the root crop, e.g. sugar beet, without topping or after only the preliminary topping stage and to subsequently remove the outer surface material at a topping station after the lifting operation. It will be appreciated that some at least of the teachings of the present invention have application to the removal of material from such lifted root crop. Accordingly, and in accordance with a second aspect of the present invention, there is provided a root crop topping assembly which comprises conveying means for conveying harvested root crop through a topping station and a rotary device at said station mounted for rotation about an axis e.g. which is substantially transverse to the direction of movement of the crop through the topping station, the device including a number of skewed and/or shaped cutter bars symmetrically disposed about said axis and adapted to engage the crop to remove skin from the crowns of the crop and leave on each crown a generally domed residue. The previous description of the various preferred forms of rotary device etc. applies also to this aspect of the present invention. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figures 1 and la to lh show perspective views of rotary devices for use in the topping assembly; Figures 2 and 3 are schematic perspective and plan views of a harvester according to the present invention with only those elements pertinent to the present invention being illustrated; Figure 4 shows a leading arm arrangement for mounting the topping assembly on a single-row root crop harvester such as that illustrated in Figures 2 and 3; Figure 5 shows in simplified plan view the mounting arrangement for a multi-row harvester; and Figure 6 shows a harvested beet which has been topped in situ by the topping assembly of the present invention. Referring first to Figures 2 and 3, a single-row root crop harvester 4 in accordance with a preferred embodiment of the present invention comprises a wheeled frame 10 supporting a beet topping assembly 11 and a beet lifting device 12. Reference numeral 18 indicates the crown-engaging rotary device of assembly 11. The topping assembly 11 is preceded by a preliminary topping device in the form of a flail 13 positioned at the forward end of the assembly to remove leaf material. Ideally, it will leave about 50 mm of leaf stalk on the crowns. In an alternative embodiment (not shown), the topping assembly 11 and lifting device 12 are spaced laterally apart from the flail 13 by an appropriate amount e.g. 500 mm, so that the flail operates on the preceding row (6) to that being topped and lifted. The lifting device 12 is of conventional construction and comprises Maynard-type lifting wheels 14 adapted to lift the topped beet from the soil and deposit it on a conveyor 15. The beet is then passed to a conveyor 16 which conveys it to a hopper 17 for subsequent discharge from the harvester. In the illustrated embodiment, device 18 and flail 13 are driven hydraulically but if desired they can instead by driven mechanically from the power take-off 8 of the towing vehicle 9. As will be seen from Figure 1, the device 18, shown diagrammatically in Figures 2 and 3, comprises two circular end plates 19 interconnected by a support tube 104 through which the threaded end of the shaft can be passed to carry a retaining nut acting on the inner face of the end plate concerned. Conveniently the tube 104 is also keyed to the shaft to help prevent any relative motion between the two items. As the unit is symmetrical, it can be mounted from either, side so that wear on the cutter bars can be evened out. In the embodiment illustrated, the diameter of end plates 19 is 300 mm and the crown-engaging part of the device is provided by the six cutter bars 108 welded at 450 to the end plates 19 and equally spaced about the rotation axis of the devices as shown. The centre points of the bars are interconnected by a smaller diameter crown-sensing plate 110, e.g. 260 mm diameter. Figure 4 shows the preferred method of mounting a rotary device (18) on the frame 40 of a single-row harvester using a leading arm arrangement. Thus referring now to Figure 4, it will be seen that a bracket member 43 depending from the harvester frame 40 provides a pivotal support for the rear end of a leading arm 45 which is secured at its front end to an apertured mounting plate 41 for a hydraulic motor 42. On the other side of plate 41 is a rotary device 18 secured to the shaft of motor 42 in the manner above described with reference to Figure 1. Reference numeral 46 indicates an optional angle adjustment plate for the arm 45. In addition, vertical adjustment of the support pivot 100 is provided at 101 so that the position of the pivot can be set to correspond to the working depth of the lifting wheels 14. The motion of arm 45 may be controlled by a damper 47 acting between arm 45 and the harvester frame 40 and/or by a compression spring 48 acting between stops 49, 50 on the two parts of the damper and embracing the damper 47. The purpose of spring 48 is to urge the rotary device 18 downwardly into skin-abrading engagement with the root crop crowns while that of damper 47 is to discourage "bounce" when the device rolls over the root crop crowns and similar irregularities in the soil profile. The arrangement is completed by a limit chain 55 provided to limit downward movement of the arm 45 to prevent device 18 digging itself into the ground. The advantage of a leading arm arrangement over a trailing arm arrangement is that it is an inherently stable configuration. In use of the assembly above described for sugar beet topping, say the harvester 4 is towed in direction A (Figures 2 and 3) over the sugar beet rows so that the flail 13, topping assembly 11 and lifting device 12 operate in succession as shown. The speed of rotation of the rotary device 18 in assembly 11 will be chosen having regard to the translational speed of the harvester to leave a domed core of acceptable interior material. Typically, where the rotary device is a device 18 of about 300 mm diameter it would rotate at 750 to 800 rpm for a harvester moving at 3 to 5 km per hour. Higher rotational speeds of up to 1100 rpm can be used for greater harvester speeds of 6 to 8 km per hour. Figure 5 shows one way of mounting a number of single-row rotary devices 18 on the harvester frame 40 to provide a multirow arrangement 62. Once again a leading arm assembly is used, this time with the arms 64 pivotally supported on bearings 66 from a common frame-supported shaft 68. Each arm 64 takes the form of a hollow casing which houses a chain and sprocket connnection 70, 71, 72 between shaft 68 and drive shafts 74 for the individual rotary devices 18. The end plates 19 of each rotary device are in this case welded to a drum 76 supported on a bearing 78 on the associated arm 64. Each drum 76 has an end plate 80 presenting a key way 82 arranged to register with a corresponding key 84 on the shaft 74. A retention nut (not shown) on the end of shaft 74 abuts with end plate 80 to hold the device 18 in place. As before, each leading arm has provision for a damper and/or spring and limit chain associated with it, though for clarity only the damper 47 and chain 55 for one of the arms has been shown and the spring mounted on that damper has been omitted. It is intended that beet which has been topped by the topping assembly 11 should have the domed shape shown in Figure 6 of the drawings. It will be appreciated that the harvesters according to the present invention are not restricted to the details particularly described above with reference to the drawings. In particular, flail 13 could be omitted or replaced by an alternative preliminary topper, such as a knife rotating about a substantially vertical axis. Similarly, an alternative lifting device could be employed. The broader aspects of the invention, e.g.#as including a stationary crop topping assembly, have been indicated above. It is also envisaged however that the same device, e.g. in the form illustrated in Figure 1, could be used as a power tool attachment. As already indicated, Figures la and lb illustrate alternative forms of rotary device to that shown in Figure 1 in so far as the skewed straight-edged cutter bars 108 of the Figure 1 embodiment are replaced by less skewed (Figure lb) or axially parallel (Figure la) cutter bars having their cutting edges correspondingly shaped so as in each case, on rotation of the device, to lie on the same concave wall portion as that swept out by the cutting edges of bars 108 in the Figure 1 embodiment. In the alternative embodiments of Figures ic to le the crown-sensing disc 110 and support tube 104 of the earlier embodiments are omitted and the circular end plates of the device are interconnected by the cutting bars 108 which have been increased in number from six to twelve. At least one of the two end plates 19 carries a circular support plate 204 through which the threaded end of the shaft can be passed to carry a retaining nut acting on the inner face of the end plate concerned. Conveniently the plate 204 is also keyed to the shaft to help prevent any relative motion between the two items. As the unit is symmetrical, it can be mounted from either side so that wear on the cutter bars can be evened out. In the embodiment illustrated, the diameter of end plates 19 is once again 300 mm but the crown-engaging part of the device is 0 now provided by the twelve cutter bars 108 welded at 45 to the end plates 19 and equally spaced about the rotation axis of the devices as shown. If desired, the embodiment of Figure ld may be modified by having the centre points of the bars 108 interconnected by a smaller-diameter crown-sensing plate 110 as shown in Figure lf. With the preferred dimensions quoted above for the earlier embodiments, the diameter of plate 110 would typically be 260 mm for example. The embodiments of Figures lc and le may be similarly modified. In all such modifications, plates 204 are advantageously replaced by the support tube 104 of the first embodiments. Another modification is shown in Figure lh which depicts a rotary device 18 having the cutter bar configuration of Figure 1c but with each cutter bar twisted so as at all points to have its major cross-sectional dimension radially disposed in device 18. Twisting the cutter bars in this way ensures that the angle of attack is the same along the length of the bar. This is advantageous as it results in the wear on each cutter bar being spread more or less equally along the length of the cutting edge. It is therefore intended that all the other skewed-bar embodiments of the present invention may also incorporate this twist feature, in particular, though not exclusively. the embodiments and modifications shown in, and/or described with reference to, Figure 1, lb, le and 1 (described below). In this latter respect, it will readily be appreciated that the illustrated embodiments and their modifications can be modified in exactly the same way as was the embodiment of Figure Ic, i.e. by replacing the essentially flat cutter bars shown in these figures by twisted radially-disposed cutter bars of the sort shown in Figure lh. Further modifications of the above described embodiments differ from those illustrated only by the number of cutter bars present, and/or by their inclination, and/or by the exact profile of their cutting edges, and/or by the presence or absence of a crown-sensing plate, and/or by the method in which the device is to be supported, and/or by the dimensions or relative dimensions of the different parts of the device. One such modification, already referred to above, is shown, by way of example only, in Figure 1 which depicts a rotary device 18 having the cutter bar configuration of Figure la and the support system of Figures lc to le or lh. It will be understood that whether in the context of a root crop harvester or a topping assembly or a power tool attachment, the rotary device of Figure 1 can in each case be replaced by an equivalent device of the form illustrated in Figures la to lh or in a modification of these forms as above described.

Claims: CLAIMS 1. A root crop topping assembly adapted for translational movement over soil containing a row of root crop, the assembly being characterised in that it comprises a rotary device including a number of skewed and/or shaped cutter bars symmetrically disposed about the rotation axis of the device and adapted on rotation of the device to sweep out a generally cylindrical shape having a concave wall portion designed to engage the crop in situ to remove surface material from the exposed crowns of the crop and leave on each crown a generally domed residue. 2. An assembly as claimed in Claim 1 characterised in that the cutter bars are provided by substantially straight-edged bars skewed at between 300 and 600 to an imaginary reference plane lying perpendicular to the rotation axis of the device. 3. An assembly as claimed in Claim 1 characterised in that the cutter bars lie substantially parallel to the rotation axis of the device and have their cutting edges shaped so as on rotation of the device to lie on said concave wall portion. 4. An assembly as claimed in Claim 1 characterised in that the cutter bars are skewed and the cutting edges of the bars are shaped so as on rotation of the device to lie on said concave wall portion. 5. An assembly as claimed in Claim 2 or Claim 4 characterised in that the cutter bars are twisted so as at all points to have the major cross-sectional dimension of each cutter bar radially disposed in the device. 6. An assembly as claimed in any preceding claim characterised in that it has more than eight said cutter bars. 7. An assembly as claimed in any preceding claim characterised in that it includes a crown-sensing disc. 8. A root crop harvester incorporating a topping assembly according to any of Claims 1 to 7 characterised in that the topping assembly is mounted on the frame of the harvester by means of a leading arm arrangement adapted to urge the assembly into the desired optimum crop-topping relationship. 9. A root crop topping assembly characterised in that is comprises conveying means for conveying harvested root crop through a topping station and a rotary device at said station mounted for rotation about an axis and including a number of skewed and/or shaped cutter bars symmetrically disposed about said axis and adapted to engage the crop to remove surface material from the crowns of the root crop and leave on each crown a generally domed residue. 10. A rotary device characterised in that it includes a number of skewed and/or shaped cutter bars symmetrically disposed about the rotation axis of the device and adapted on rotation of the device to sweep out a generally cylindrical shape having a concave wall portion. 11. A rotary device as claimed in Claim 10 characterised in that it is adapted for use as a power tool attachment.

Inventors: BUTLER, JOHN
Applicants: NATIONAL RESEARCH DEVELOPMENT CORPORATION
Application year: 1983
Main classification: A01D23
IPC codes: A01D23, A01D33