GB2149632A - Cultivator tool - Google Patents

Abstract

A tool for a cultivator such as a rotary harrow is provided. This tool has a part (1) attachable to a support and a blade part (2), both of which parts are stiffened by webs (3, 7) respectively. A web-free region is provided on the blade part (2) in the vicinity of the junction (5) of the parts (1) and (2) to give the tool a degree of local flexibility. <IMAGE>

Description

SPECIFICATION Cultivator tool The present invention relates to a tool for a cultivator such as a rotary harrow.

Because of ever increasing agricultural mechanization, soil-working machines such as milling cutters, harrows orthe like are increasingly utilised. These machines, although they have been known in general for sometime, are continually being modified and improved. However, special care must be taken in the design of the tools, which are subjected to the maximum wear and stress in that they act directly on the soil. Consequently, any improvement made to the tools improves the efficiency of the whole machine.

Tool stress and wear are particularly noticible in rotary harrows, where the tools are mounted on supports each rotating contrariwise to the adjacent tools, so thatthetrajectories ofthe tools cut across each other.

Moreover, the characteristics these tools should desirably have are quite incompatible. Thus on the one hand they should be very rugged in order notto be damaged bystonesorthe like, and on the other hand, theirsizeorthicknessshould be limited so as notto requiretoo much drive power in the machine.

There isthus a need for a generally improved tool for a cultivatorsuch as a rotary harrow which is sufficiently rugged, yet requiring minimum working power.

According to the present invention there is provided a tool fora cultivatorsuch as a rotary harrow, including a first part for attachment to a support, and an operative blade part, both of which parts are stiffened bywebs, there being a web-free region on the blade part in the vicinity of the junction of the blade and first partsto givethetool a degree of local flexibility.

For a better understanding ofthe present invention, andto show how the same may be carried into effect reference will now be made, by way of example to the attached figures, in which: Figure lisa perspective view of a tool according to the invention; Figure 2 is a side view of the tool of Figure 1; and Figures 3,4and 5 are cross-sectionstaken along the lines AA, BB and CC respectively of Figure 2.

Atool according to the invention consists basically oftwo parts; namely a first part 1 forattachmentto a support on the machine, and an operative blade part 2 forming with the first part 1 an angle of at least 90'or substantially perpendicular thereto.

Although in the accompanying figures the parts 1 and 2 are substantially orthogonal,this characteristic is notto be regarded as limiting, since, according to requirements, the operative part2 ofthetool may even diverge a little.

Part lisa substantially flat plate-like element, stiffened by a central web 3, and is provided with a pair of holes 4 serving for as many bolts, used for securing the tool to the relevant support.

The web 3 can be set in the lowerand/orinthe upper surface of part 1, according to the system used for mounting the tool. The web 3, in fact, also allows the blade part 2 to be positioned on the relevant support more quickly and precisely. This web 3 runs along the whole length of part 1 and extends into the junction region 5 between parts 1 and 2.

The operative blade part 2 of the tool has, at its free tip end, a flattened hexagonal section 6, which gets longer as the blade partwidens towards the junction region 5, though the original thickness remains substantially unchanged.

An outer web 7 runs substantially centrally along the operative blade part 2 of the tool, from the region to close to the lowerextremityorfreetip end. The function of this web 7 isto serve for stiffening the blade part 2, making it rugged enough to withstand impact with obstacles when working, and for shifting slightly clods of earth justworked, thus diminishing friction between the outer surface of the blade part and the soil.

In fact, asthe motion of a conventional tool is a combination of rotary motion around the axis of the support and the translation motion of the entire machine, the outer surface ofthe blade part is pressed againstthe ground during the forward movement, thus absorbing power byfriction and wearing more rapidly. However in the tool of the invention the web 7 makes the worked clods shift slightly, so that the rear portion ofthe blade part 2 does not press againstthe soil, but serves only for making to tool rugged enough.

It shou Id be notedthata gap orweb-free region is provided on the blade part 2 between the webs 3 and 7, in the vicinity to the upper part ofthetool,that isto say in the vicinity of the junction between the parts 1 and 2. This web-free region gives the tool a degree of local flexibility, so as to avoid damage even in the case that stones or other obstacles get stuck between two tools rotating in opposite directions.

To solve the inconveniences caused byfriction between the blade and the soil some known tools have the operative blade parttwisted around their own axes, so asto form with the ground a certain rake.

However, as it is also required that the operative part of the blade part be inclined, so that the tool is self-cleaning, it has hitherto been necessary to produce different kinds of tools in accordance with the direction of rotation of the rotors on which they were to be mounted.

On the contrary, the tool according to the present invention can be mounted on supports rotating either clockwise or anticlockwise, as the blade part 2 has both sides inclined, while the presence of the web 7 provides the results previously obtainable by tools that were twisted with respect to their own axes.

The tool according to the invention is slightly curved in the junction region 5 so as to be slightly convex. In this way, justwhere the greatest stress occurs, the section is widened and increased so asto be more resistant.

The tool of the invention whilst being as rugged as conventional tools, generally requires less power to operate. Additionally it can be used for right or left handed rotation which hithertofore required two different kinds oftool.

The tool preferably is made of steel, but any other suitable material can be used as well. The sizes too are not to be considered as limiting: for instance, the length of part 1 can be greaterthan it appears in the drawing, making it possible to use this tool, or anther substantially analogous tool, on milling cutters or other cultivators with horizontal axis.

Claims (5)

1. Atool fora cultivator such as a rotary harrow, including a first partforattachmentto a support, and an operative blade part, both ofwhich parts are stiffened by webs, there being a web-free region on the blade part in the vicinity of the junction ofthe blade and first parts to givethetool a degree of locai flexibility.

2. Atoolaccordingtoclaim 1, wherein the operative blade part is of substantially constant thickness and has a width decreasing towards a free tip end ofthe blade part, a longitudinal web being provided on the outer surface ofthe blade part, substantially in a central zone ofthe blade part.

3. Atool according to claim 1 or claim 2, which is convex atthejunction between the first part and the blade part, so as to provide a wider resistant section.

4. Atoolaccordingtoanyoneofclaimsl to3, wherein the blade part extends substantially perpendicularto the first part.

5. Atool for a cultivatorsuch as a rotary harrow, substantially as hereinbefore described with reference to the accompanying drawings.