WO1987004893A1

WO1987004893A1 - Subsoil aerator

Info

Publication number: WO1987004893A1
Application number: PCT/GB1987/000119
Authority: WO
Inventors: Joseph Gardner
Original assignee: Joseph Gardner
Priority date: 1986-02-20
Filing date: 1987-02-18
Publication date: 1987-08-27
Also published as: AU7031287A; GB8604258D0

Abstract

A subsoil aerator comprising a blade (19) mounted on a frame (1, 2, 3) which in use is connected to a towing vehicle. The blade (19) is reciprocated relative to the frame (1, 2, 3) so as to assist the progress of the blade (19) through subsoil, the blade (19) reciprocating in a vertical plane extending in the direction in which the blade (19) is being towed.

Description

SUBSOIL AERATOR

The present invention relates to a subsoil aerato . Subsoil aerators are used to disturb the subsoil of agricultural land so as to improve drainage and combat soil compaction which has become an increasing problem as the weight of agriculatural machinery has increased. Subsoil aerators are also used to penetrate the soil so as to enable the injection of slurry into the soil.

Known subsoil aerators comprise one or more blades which are dragged through soil to be aerated with the tip of the blade at a depth of for example 50cm. The depth to which the blade or blades of the aerator penetrates the ground means that a very large force is required to drag the aerator blades through the soil particularly in those conditions where the use of a subsoil aerator is most beneficial. This means that a very high powered tractor is often required, particularly if more than one blade is to be used.

It has been proposed to vibrate agricultural machinery to improve the .penetration of that machinery into land being worked. In one known arrangement the entire frame of a towed agricultural implement is vibrated so as to transmit vibrations down to land working implements. Such vibrating mechanisms provide only a limited improvement in performance.

It is an object of the present invention to obviate or mitigate the above problems.

According to the present invention there is provided a subsoil aerator comprising at least one blade mounted on a frame which in use is connected to a towing vehicle, and means for reciprocating the said at least one blade relative to the frame so as to assist the progress of the said at least one blade through subsoil. Preferably, the or each blade is reciprocated in a vertical plane extending in the direction in which the blade is being towed.

Preferably, the blade is reciprocated both in the horizontal and vertical directions. The or each blade may be ^'reciprocated by engagement with a cam driven by a cam shaft extendi-ng transversely relative to the frame. The or each blade may define a circular aperture through which the cam shaft extends and against the periphery of which the cam supported by the cam shaft bears. Thus, as the cam rotates the centre of the circular aperture foϊlows a circular path centred on the axis of the cam shaft. If two or more blades are provided, they are preferably reciprocated out of phase with each other.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which :-

Fig. 1 is a side view of an embodiment of the invention hitched to the back of an agricultural tractor;

Fig. 2 is a view on the lines II-II of Fig. 1 after disconnection of the embodiment of the present invention from the towing tractor; and Fig. 3 is a more detailed illustration of the interconnection between a blade of the embodiment of Figs. 1 and 2 and the frame on which it is supported.

Referring to the drawings, the illustrated embodiment of the invention comprises a frame fabricated from square section steel tube including a front member 1, two substantially identical side members 2, and a rear member supporting brackets 3. Two plates 4 extend upwardly from the front member 1 to a top bracket 5 and a bracing link 6 extends from the bracket 5 to the rear member. When the frame is hitched to a towing vehicle as shown in Fig. 1 an upper link 7 is pivotally connected to the bracket 5 and two lower links 8 are connected to the ends of the front member 1. The links 7 and 8 are connected to suitable brackets on the towing vehicle, for example upper towing pivot 9. The vertical position of the frame can be controlled by lifting the links 8 so that they pivot about their points of connection to the towing vehicle. The lifting mechanism is of conventional design and accordingly is not illustrated herein.

The front member 1 of the frame supports a gearbox 10 having a splined input shaft 11 coupled to a power take off 12 of the towing vehicle by a transmission shaft 13. Toothed wheels 14 are supported on an output shaft 15 of the gearbox and drive a cam shaft 16 via chains 17. The cam shaft 16 is supported on suitable bearings (not shown in detail) mounted on the frame. As best seen from Fig. 3, the cam shaft 16 extends through circular apertures 18 in a pair of blades 19. Each blade is also connected to a respective bracket 3 by a pivotal link 20. The pivotal link defines three apertures 21 and the bracket 3 defines four apertures 22 so that the effective length of the link 20 can be adjusted to adjust the angular position of the blade 19 relative to the cam shaft 16.

In the region of the cam shaft 16 which passes through the apertures 18 in the blades 19 the cam. shaft 16 supports two cams 23. The cams 23 are 180° out of phase with each other relative to the camshaft. Thus as the cam shaft 16 rotates the cams

23 about the cam shaft axis the centres of the apertures 18 execute a circular motion about the cam shaft axis. This has the effect of moving the blade in a vertical plane parallel to the direction in which the blade is dragged through the ground. Fins

24 supported on the tip of the blade 19 are thus moved backwards and . forwards and up and down even when the vehicle pulling the blade .is stationary. Because the cams 23 are out of phase with each other, the movements of the blades 19 are also out of phase so that for example as one blade moves up the other . moves down. The relatively small movements of the blades have the effect of dramatically reducing the force required to pull the blades through the ground and thus either a smaller towing vehicle or a greater number of blades can be used as compared with prior art subsoil aerators in which the blades do not reciprocate relative to the towed frame.

The arrangement described herein provides a much greater degree of improvement in performance than the known vibrating mechanisms described above. Reciprocation of the blades so as to cause both forwards and upwards movement is preferred. In a prototype device of the type illustrated in the accompanying drawings two blades were provides which extended into the ground to a depth of 50cm and a cam was used on each blade such that on each rotation of the cam the bottom of the blade moved forward and backwards a distance of approximately 5cm and up and down a distance of approximately 1cm. A remarkable performance was achieved as two blades were pulled through earth frozen to a depth of approximately 10cm by a small agricultural tractor. It is also preferred to have more than one blade and to reciprocate the blades out of phase with each other. For example in the illustrated two blade system the 5 cams which cause the blades to reciprocate are 180° out of phase. In a three blade arrangement the cams would be preferably 120° out of phase, and in a four blade arrangement the cams would be preferably 90° out of phase. The cam shaft can be rotated at a rate 10 of for example 500 revolutions per minute.

15

20

25

r-

30

35

Claims

CLAIMS :

1. A subsoil aerator comprising at least one blade mounted on a frame which in use is connected to a towing vehicle, and means for reciprocating the said at least one blade relative to the frame so as to assist the progress of the said at least one blade through subsoil.

2. A subsoil aerator according to claim 1, wherein the reciprocating means is adapted to reciprocate the or each blade in a vertical plane extending parallel to the direction in which the blade is to be towed.

3. A subsoil aerator according to claim 2, wherein the reciprocating means is adapted to reciprocate the or each blade in the horizontal and vertical directions.

4. A subsoil aerator according to claim 3, wherein the reciprocating means comprise a cam driven by a cam shaft extending transversely relative to the frame, the or each blade defining a circular aperture through which the cam shaft extends and against the periphery of which the cam driven by the cam shaft bea s.

5. A subsoil aerator according to claim 4, wherein the or each blade is secured to the frame by a pivotal link.

6. A subsoil aerator according to claim 2, 3 or

4, comprising two or more blades, wherein the reciprocating means is adapted to reciprocate the blades out of phase with each other.

7. A subsoil aerator substantially as hereinbefore described with reference to the accompanying drawings.