GB2073001A - Harrows - Google Patents

Abstract

A harrow comprises a frame (1) carrying ground-engageable tines and adapted to be towed by a tractor. The frame (1) also carrying at its leading end, a ground-engageable bar (2A) which extends transversely of the frame and is connected to the lower ends of a plurality of upstanding levers (2B) which are pivotally mounted on the frame about a transverse axis and are urged by springs (2D) to a position in which the bar (2A) engages the ground. The springs (2D) permit the levers to pivot so that in use, if the bar (2A) meets an obstruction such as a large stone, the bar can swing rearwardly and upwardly and ride over the obstruction. Preferably, there is at least one transversely extending row of spring tines (3), and to the rear of said spring tines, a sub-frame (4) carrying at least one transversely extending row of substantially rigid tines (5), said sub-frame being located below the main frame (1) and being mounted thereon so as to be swingable fore-and-aft in order that it may follow the ground contour, and being urged by springs (8) to a position in which said rigid tines (5) and the sub-frame (4) engage the ground. <IMAGE>

Description

SPECIFICATION Improvements relating to harrows This invention relates to harrows.

According to the present invention there is provided a harrow comprising a frame carrying ground-engageable tines and adapted to be towed by a tractor, said frame also carrying at its leading end a ground-engageable bar which extends transversely of the frame, said bar being connected to the lower ends of a plurality of upstanding levers which are pivotally mounted on the frame about a transverse axis and are urged by springs to a position in which the bar engages the ground, and said springs permit the levers to pivot so that in use, if the bar meets an obstruction such as a large stone, the bar can swing rearwardly and upwardly and ride over the obstruction.

Further, according to the present invention there is provided a harrow comprising a main frame adapted to be towed by a tractor, said frame carrying at least one transversely extending row of ground-engageable spring tines, and, to the rear of said tines, a sub-frame carrying at least one transversely extending row of substantially rigid tines, said sub-frame being located below the main frame and being mounted thereon so as to be swingable fore-and-aft in order that it may follow the ground contour, and being urged by springs to a position in which said rigid tines and the sub-frame engage the ground.

Still further, according to the present invention there is provided a harrow comprising a main frame adapted to be towed by a tractor, said frame carrying at the front a soil-levelling bar which is displaceable rearwardly and upwardly against the action of springs to enable it to ride over obstruction's, at least one row of spring tines to the rear of said bar, and, to the rear of said tines, a sub-frame which carries at least one row of substantially rigid tines, which is located below the main frame, is swingably mounted on the latter so that it may follow the contour of the ground, and which is spring-urged towards the ground.

Preferably, said main frame also carries at the rear a sparred open-work roller or so-called crumbler roller.

Preferably also, there are two rows of spring tines, and three rows of rigid tines.

Preferably also, the rigid tines operate, in use, at a depth greater than the spring tines.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying partly diagrammatic drawings, in which: Fig. 1 is a side view of a harrow embodying features in accordance with the present invention; Fig. 2 is a plan view on one side of the foreand-aft axis of the harrow, the other side being the same; and Fig. 3 is a fragmentary front view.

Referring to the drawings, a harrow consists generally of a rectangular main frame 1, and, mounted one behind the other on the frame 1, a breaker or levelling bar assembly 2; spring tines 3; a rectangular sub-frame 4 carrying substantially rigid and rearwardly and downwardly inclined tines 5; and a so-called crumbler roller 6.

The assembly 2 consists of a ground-engaging bar 2A which is spaced below the frame 1, extends from side-to-side of the frame 1, and is connected to the lower ends of a plurality of upstanding levers 2B. The latter are pivotally mounted intermediate their ends on the frame 1 by pins 2C, and a plurality of tension springs 2D urge the levers 28 to a limit position shown in Fig. 1 in which the bar 2A engages the ground.

Thus, if the bar 2A meets an obstruction, such as a large stone, the bar can pivot rearwards and upwardly (i.e. anti-clockwise in Fig. 1) and ride over the obstruction. The rear ends of the springs 2D are connected to lugs on a cross-member 1A (Fig. 2) of the frame 1.

There are preferably two rows of the tines 3 located one behind the other, with the tines in the two rows being mutually staggered, as shown in Fig. 2, and the tines being attached to cross members 1 B of the frame 1.

The sub-frame 4 is spaced below the main frame 1 and is pivotally mounted on the latter by parallel links 7 so as to be swingable fore-and-aft.

There are preferably three rows of tines 5 attached to three cross members 4A (Fig. 2) of the subframe 4, the tines in the rows are mutually staggered, and there are more tines 5 in a row than there are spring tines 3 in a row. The subframe 4 is urged downwardly and forwardly by tension springs 8, of; which only one is shown, and which are connected at the front ends to lugs on the cross member 1 A of the frame 1, and at their rear ends to lugs on the rear cross member 5 of the sub-frame.

The crumbler roller 6 is carried rotatably at the rear ends of two arms 9 which project rearwardly from the frame 1. The front end of each arm 9 is pivotally connected to the frame 1 by a pin 10 so that the roller 6 can be raised or lowered relative to the frame 1. Each arm 9 is heid in its adjusted position by a pin 11 which passes through a selected one of a plurality of spaced holes 12 in a bracket 13 on the arm and into a hole in the adjacent side member of the frame 1.

Also at the front of the main frame 1, there is a coupling device 14 (Fig. 3) connectible to the three-point hitch linkage of a tractor.

The coupling device 14 consists of two pairs of spaced lugs 1 5 secured to the front cross member 1 C of the frame 1, and a pair of lugs or flanges 1 6 spaced above and midway between the lugs 1 5.

The lugs 1 5 are provided with opposed holes 1 SA (Fig. 1) so that the lower or draft iinks of the hitch linkage of a tractor can be connected thereto by pins, and the upper lugs 16 also have opposed holes 1 6A (Fig. 1) for use in connecting the top link.

The lugs or flanges 1 6 are formed at the upper ends of laterally opposed inclined straps 1 7 whose lower ends are bolted respectively to the inner lugs of the two pairs 15. The lugs 16 are connected by a bolt 18 and a nut 19, the bolt 18 passing through a spacer bush 20 and the upper ends of a pair of struts 21 whose other ends are bolted to lugs 22 on the cross-member 1 A of the frame 1.

In use, the harrow is towed, in the condition shown in Fig. 1, over ground to be prepared for sowing. The bar 2A engages the soil, generally levels it, breaks up clods of earth, and sweeps along small stones, and, as previously explained can swing rearwards to ride over obstructions such as large stones.

The spring tines 3 dig into the soil, breaking it up and generally loosening it.

The tines 5 operate at a greater depth than the tines 3, and they break up the soil further, and the sub-frame 4 also engages the soil to effect further levelling. Moreover, as the sub-frame 4 with the tines 5 is swingably mounted, it follows the ground contour, so that the depth of the tilth is kept substantially uniform. It can, of course, also ride over obstructions.

The crumbler roller 6 breaks up any remaining lumps or clods of soil, and provides a final levelling effect.

With a harrow as above described, a ievel seed bed can be prepared in one pass of the harrow in suitable ground conditions, so that the formation of level seed beds can be carried out more quickly than hitherto, especially on stony ground.

Moreover, due to the pivotal mounting of the breaker bar and the times 5, the possibility of these parts being damaged by obstructions is eliminated or greatly reduced.

Claims (7)

1. A harrow comprising a frame carrying ground-engageable tines and adapted to be towed by a tractor, said frame also carrying at its leading end a ground-engageable bar which extends transversely of the frame, said bar being connected to the lower ends of a plurality of upstanding levers which are pivotally mounted on the frame about a transverse axis and are urged by springs to a position in which the bar engages the ground, and said springs permit the levers to pivot so that in use, if the bar meets an obstruction such as a large stone, the bar can swing rearwardly and upwardly and ride over the obstruction.

2. A harrow comprising a main frame adapted to be towed by a tractor, said frame carrying at least one transversely extending row of groundengageable spring tines, and, to the rear of said spring tines, a sub-frame carrying at least one transversely extending row of substantially rigid tines, said sub-frame being located below the main frame and being mounted thereon so as to be swingable fore-and-aft in order that it may follow the ground contour, and being urged by springs to a position in which said rigid tines and the sub-frame engage the ground.

3. A harrow comprising a main frame adapted to be towed by a tractor, said frame carrying at the front a soil-levelling bar which is displaceable rearwardly and upwardly against the actions of springs to enable it to ride over obstructions, at least one row of spring tines to the rear of said bar, and, to the rear of said tines, a sub-frame which carries at least one row of substantially rigid tines, which is located below the main frame, is swingably mounted on the latter so that it may follow the contour of the ground, and which is spring-urged towards the ground.

4. A harrow as claimed in claim 2 or 3, in which said main frame also carries at the rear a sparred open-work roller or so-called crumbler roller.

5. A harrow as claimed in any one of claims 2 to 4, in which there are two rows of spring tines and three rows of rigid tines.

6. A harrow as claimed in any one of claims 2 to 5, in which the rigid tines operate, in use, at a depth greater than the spring tines.

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