GB2158738A

GB2158738A - Soil-separating assemblies

Info

Publication number: GB2158738A
Application number: GB08511837A
Authority: GB
Inventors: Douglas Charles Mcrae; Philip Scott Hutchison
Original assignee: National Research Development Corp UK
Current assignee: National Research Development Corp UK
Priority date: 1984-05-14
Filing date: 1985-05-10
Publication date: 1985-11-20
Also published as: GB8412239D0; NL8501266A; DE3517214A1; GB2158738B; GB8511837D0

Abstract

A root-crop harvestor 10 includes double disc shares 49 for lifting the crop on to the variable area sieving section 33 of a conveyor sieve 12. Nose cones 14 and a roller 17 form part of a web support system mounted on swing-links 40, 41,43. These links allow agitation of the section 33 in the plane of movement of the sieve to take place by bodily movement of that section rather than by movement of just one end of it. The area of section 33 can be altered to suit the prevailing conditions by an appropriate resting of the carriage 45 bearing roller 17. <IMAGE>

Description

SPECIFICATION Soil-separating assemblies The present invention relates to soil-separating assemblies e.g. for use in or with root-crop harvesters, in particular, but not exclusively, potato harvesters.

GB 2077626B (NRDC) discloses a soil-separating assembly comprising a variable-area conveyor sieve for transporting the crop rearwardly from the crop lifting means to another part of the assembly.

In a preferred embodiment of this prior invention, agitating means were provided for imparting mainly horizontal vibrations to a sieving section of the conveyor sieve to accomplish a superior soilsieving rate per unit area with less tuber damage than was possible with previously available systems.

An object of the present invention is to provide a means for more effectively isolating these vibrations from the other parts of the conveyor-sieve.

Thus according to the present invention, where a soil-separating assembly for use with root-crop lifting means comprises a conveyor sieve for transporting the crop from the crop lifting means to another part of the assembly there is provided agitation means for imparting mainly horizontal accelerations to a variable-area sieving section of the conveyor-sieve by bodily displacing the whole of that section rather than be vibrating the sieving area from one end of that section as disclosed in GB 2077626B.

Conveniently, the sieving section of the conveyor-sieve passes around first and second rotatable support means one at one end and one at the other end of the sieving section and there- after in an S-shaped configuration about a third rotatable support means.

Conveniently, the separation of the first and second support means is adjustable to allow the variation of the sieving area of the conveyor sieve.

Conveniently, the agitation means comprises a swing-link support assembly.

Conveniently, the agitation means is controlled by an agitation control means operative to control the severity of the mainly horizontal agitation to be imparted to the sieving section by the agitation means.

Conveniently, the said other part of the assembly comprises a transporter section which is adjustable to compensate for any change in the delivery point of the conveyor sieve arising from a change in the effective sieving area of the sieving section. In this case, if the conveyor sieve passes around the second and third rotatable support means in an Sshaped configuration as hereinbefore described, then conveniently the transporter section is automatically adjustable by having the transporter section also pass around said third rotatable support means.

Although the transporter section may, if desired, be provided by a separate belt or the like to that providing the sieving section, in preferred embodiments a single belt or the like is used to provide both the sieving section and the transporter section.

Speed control means are preferably provided for varying the speed of the conveyor sieve independently of the ground speed of the assembly.

The invention also includes a root-crop harvester incorpora- ting a soil-separating assembly according to the present invention and in particular, but not exclusively, such a harvester in which the crop lifting means comprises a double disc share.

Where in this application the term "mainly horizontal" has been used to describe the motion of the sieving section of the conveyor sieve, it should be understood that this term is used for convenience only and should more accurately be considered as the motion of the sieving section in directions substantially parallel to the plane containing the rotation axes of the first and second rotatable support means referred to above.

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 illustrate, in diagrammatic form, a side elevation of a potato harvester according to the invention at two different stages of its operation; and Figures 3 and 4 are scrap views, on enlarged scales, of part of the same harvester respectively seen from the side and from the rear looking forwards.

Thus referring now to the drawings, a potato harvester 10 according to the present invention incorporates a soil-separating assembly in which a conveyor sieve or "web" 12 passes round nose cones 14, idler rollers 16, 17, 18, rear roller 20, drive roller 22 and slack-support rollers 24 to 27.

The nose cones 14 are mounted on a connecting rod 29 (Figures 1 and 2) which also carries support units 31 for the roller 17. In fact, the units 31 are suspended on links 43 from a carriage 45 which is movable with the units 31 to any one of a number of positions in which it can be secured to the machine chassis.

The sieving section 33 of the web is the section lying between nose cones 14 and roller 17 and the effective area of this section can be varied at will by sliding the carriage 45 supporting the units 31 to some new position along the connecting rod 29.

The units 31 are secured in their new positions using the spring loaded taper pins 35, 36 of Figures 3 and 4. These latter lock into appropriate apertures in a finned support rail 38 forming part of the connecting rod 29.

As an alternative, the taper-pin locking system described above could be replaced by a rapid manual locking and unlocking means e.g. using a handwheel and screw or by an automatic system sensor-controlled to unlock the carriage, vary the sieving area in response to a change in the prevailing conditions and then relock the carriage in its new position.

As a further alternative, the idler roller 18 may be replaced by a sprocket driven either by hydraulic or mechanical means e.g. in fixed relationship with the main drive sprocket 22. In this case, the drive shaft to the auxiliary sprocket is an anticlockwise sense (as viewed in the drawing).

The framework is mounted from the chassis (not shown) of the machine using swing-links 40, 41 and links 43 are driven by variable stroke cranks (not shown) to provide the desired horizontal agitation of the connecting rod 29 and hence of the sieving section 33.

The carriage 45 also supports the rollers 16 and 18 referred to earlier and, if desired, the roller 18 may be spring mounted as shown further to reduce the chance of fluctuations in web tension being induced in the downstream position of the web by the vibrating motion of roller 17 during operation of the assembly.

As already described, in operation of the assembly, the links 43 are driven by variable stroke cranks (not shown) to impart the desired mainly horizontal vibrations to the sieving section 33. As a result, section 33 will accelerate in the direction of web travel during the forward stroke of the cranks and will decelerate during the return stroke of the cranks.

The amplitude of this vibratory motion can be altered to suit the prevailing conditions within the range 25 mm to 90 mm for example by altering the crank throw. Similarly, the frequency of oscillation can be similarly varied between, say, 100 per minute and 200 per minute by altering the speed of the crank drives to links 43. Typical acceleration/ deceleration values for a 25 mm amplitude stroke of the cranks might be 1.0 to 2.5 g for example.

The mixture of potatoes, stones and clods and any remaining loose soil on that portion of the web downstream of roller 17 feeds on to a plain sided delivery belt 47 either direct or via a separator unit (not shown) which could for example by an X-ray separator e.g. of the kind described in UK Patent Specification- tions 1431905, 1004222 and 984232. Reference numeral 49 indicates one of two forwardly-inclined double disc shares for lifting the crop and crop-containing earth on to the sieving section at the front of the machine. These shares may for example be two of the kind described in UK Patent Specification 1601478 or UK Patent Applications 8212478 and 8212479.The overall speed of the web 12 is controlled independently of the ground speed of the machine by means of a suitable gear box or other variable drive system.

As already described, the effective area of the sieving section can be varied at will by changing the position of the roller 17 and the carriage 45.

Figure 1 illustrates a relatively small sieving area while a near maximum value is illustrated in Figure 2. Generally speaking the operative will increase the sieving area when he judges that there is too much loose soil on the web section and will decrease it when he judges that there is too little.

These changes can be made without altering the speed of the conveyor sieve.The maximum sieving area will normally only be used to deal with exceptionally wet conditions.

Although the illustrated conveyor sieve assembly has been described as incorporated in a potato harvester, it will be appreciated that it is equally suited for incorporation, with minor modifications if necessary, into other forms of root- crop harvester e.g. harvesters for sugar beet and possibly also daffodil bulbs etc. and also in potato diggers.

Claims

1. A soil-separating assembly for use with rootcrop lifting means comprising a conveyor sieve for transporting the crop from the crop lifting means to another part of the assembly and wherein there is provided agitation means for imparting mainly horizontal accelerations to a variable-area sieving section of the conveyor-sieve by bodily displacing the whole of that section.

2. An assembly as claimed in Claim 1 in which the sieving section of the conveyor-sieve passes around first and second rotatable support means one at one end and one at the other end of the sieving section and thereafter in an S-shaped configuration about a third rotatable support means.

3. An assembly as claimed in Claim 2 in which the separation of the first and second support means is adjustable to allow the variation of the sieving area of the conveyor sieve.

4. An assembly as claimed in any preceding claim in which the agitation means comprises a swing-link support assembly.

5. An assembly as claimed in any preceding claim in which the agitation means is controlled by an agitation control means operative to control the severity of the mainly horizontal agitation to be imparted to the sieving section by the agitation means.

6. An assembly as claimed in any preceding claim in which the said other part of the assembly comprises a transporter section which is adjustable to compensate for any change in the delivery point of the conveyor sieve arising from a change in the effective sieving area of the sieving section.

7. An assembly as claimed in Claim 6 in which the conveyor sieve passes around the second and third rotatable support means in an S-shaped configuration and the transporter section is automatically adjustable by having the transporter section also pass around said third rotatable support means.

8. An assembly as claimed in Claim 6 or Claim 7 in which the transporter section is provided by a separate belt or the like to that providing the sieving section.

9. An assembly as claimed in Claim 6 or Claim 7 in which a single belt or the like is used to provide both the sieving section and the transporter section.

10. An assembly as claimed in any preceding claim in which speed control means are provided for varying the speed of the conveyor sieve independently of the ground speed of the assembly.

11. A root-crop harvester incorporating a soilseparating assembly as claimed in any preceding claim.

12. A soil-separating assembly or root-crop harvester substantially as hereinbefore described with reference to and/or as illustrated in the accompa nying drawings.