RU2359445C2 - Cutting thread of machine for pruning bushes and for lawn mower - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: cutting thread contains a central core of round section and at least one cutting rib located in external of peripheral part of thread. Each cutting rib contains teeth formed at each lengthwise cutting rib of thread. The disclosed design facilitates improving cutting ability of thread and obtaining more even cut of vegetation.

EFFECT: improving cutting ability of thread and obtaining more even cut of vegetation.

9 cl, 8 dwg

Description

The present invention relates to cutting threads for trimming and cutting vegetation, whether it is shrubs or grass used in rotary-head mechanized tillage machines, commonly referred to as shrub cutting machines (hereinafter brush cutters) and lawn mowers.

These mechanized tillage machines are usually equipped with a heat or electric motor, which drives a rotating head carrying one or more cutting threads at an increased speed of about 3000-12000 rpm. During this rapid rotation under the influence of centrifugal forces, one or more cutting threads are straightened in the radial direction and thus clean the circular zone inside which they carry out a cutting action with respect to the vegetation encountered.

Cutting yarns, usually manufactured and sold and intended for such use, are single-fiber filaments with a smooth outer surface, circular cross section, in the simplest case, most often made of synthetic material, such as polyamide.

To improve the efficiency, productivity or other qualities of such cutting threads to date, efforts have been focused on the following aspects:

a) the manufacture of cutting threads with a special cross section: in addition to the traditional round, cutting threads of various sections have already been proposed - square, polygonal (for example, pentagonal), star-shaped, gear, etc .;

b) reducing the noise of working cutting threads, for example, due to the structure or surface appearance of the thread;

c) offers of cutting threads differing in their design, namely the manufacture of cutting threads from a special material, or cutting threads characterized by a special combination of materials (forming, for example, a core and a coating of threads), or cutting threads characterized by the introduction of special fillers into the main material such as abrasive fillers.

In any case, despite the improvements already achieved as a result of research in various fields, cutting threads leave room for improvement. In particular, efforts to date to improve the cutting ability of these threads, which is, of course, the main of the desired qualities, have not yielded good enough results.

The technical result of the present invention, therefore, is to improve the cutting ability of cutting threads for brush cutters and lawn mowers through a simple technical solution, effective and economical and compatible with numerous forms and materials of threads.

The objective of the invention is to create a cutting thread for brush cutters and lawn mowers, which is the outside of the formation of the type of teeth or similar formations, one after another along the length of this cutting thread.

In one embodiment of the invention, the cutting thread has at least one cutting edge located in the longitudinal direction of the cutting thread, and at least one longitudinal cutting edge of the thread is formed by tooth-like formations or the like, and these formations like teeth or similar formations follow one after another along the length of this cutting rib.

Thus, the invention provides a cutting thread that does not differ in either a particular cross-section or a specific composition, but which contains a series of teeth or similar formations, giving them a longitudinal serrated profile along its entire length. In particular, one or more longitudinal cutting edges of this thread can form a “base” for the aforementioned formations such as teeth or the like, but it is also possible to provide for the implementation of such tooth sequences on the surface of the cutting thread outside the area of the edges of this thread, including on the surface of the cutting thread without longitudinal ribs, for example on round threads.

In all cases, such a thread has the best cutting ability, i.e. it cuts vegetation more easily, whether it is grass or shrubs.

In addition, the thread as an object of the invention provides a cleaner cut of vegetation, thereby presenting additional benefits. With a conventional round or square thread, the cut grass is damaged at its ends, resulting in rapid yellowing in the sun. While with a cutting thread with increased cutting ability, which is the object of the invention, as was proved by tests conducted by the applicant, the grass is cut much cleaner, which reduces the yellowing effect.

If the cutting thread has several cutting ribs, only some of these cutting ribs have formations such as teeth or similar formations, one after the other along the length of these cutting ribs, while the other ribs maintain a smooth surface.

In the case where the cutting thread has at least two cutting ribs equipped with formations such as teeth or similar formations following one after another along the length of these cutting ribs, it may be provided:

- that the formation of the type of teeth or similar formations are the same on all cutting ribs equipped with them, and are located equally on one and on the other ribs,

- or that these formations such as teeth or similar formations are made identical on all cutting ribs provided with them, but turn out to be shifted in the longitudinal direction on one edge relative to the other edge,

- or formations such as teeth or similar formations are made different from one rib to another.

As regards the particular form of the aforementioned formations, such as teeth or the like, provided on the cutting edges of the cutting thread or not on these edges, various configurations are provided. So, the entities in question may have the following form:

- teeth of the same shape and height, giving, in particular, to each cutting edge in question, "sawtooth" look,

- or teeth of unequal shape and / or height, but they can be repeated with a predetermined "step", in particular, along the length of the cutting rib in question,

- or teeth with a rounded profile, concave or convex,

- or formations in the form of notches, grooves, notches, following one after another with an interval along the length of each cutting rib in question,

- or more or less pronounced undulation provided on each cutting edge in question.

The invention will be more clearly understood using the description that follows, with reference to the accompanying schematic drawings, representing, as a non-limiting example, several manufacturing options for this cutting thread for a brush cutter and lawn mower:

figure 1 is a perspective view of a portion of the cutting thread according to the invention;

figure 2-5 is a perspective view similar to figure 1, showing part of other cutting threads according to the present invention;

6 - shows in side view a portion of another cutting thread according to the invention,

7 and 8 is a partial side view of the cutting threads according to the invention with teeth of a private profile.

Figure 1 on an enlarged scale shows part of the cutting thread 2 for brush cutters or lawn mowers, showing a section of this thread. The cutting thread 2 here has a star-shaped cross section with a central core 3 of circular cross section and four longitudinal cutting ribs 4 located crosswise in the outer or peripheral part of the thread 2.

On each longitudinal cutting edge 4 of the thread 2, teeth 5 are formed, identical in shape and height to a rounded concave profile, which follow one after another along the length of this cutting edge 4. The teeth 5 are also formed on each cutting edge 4, and they can be located in accordance with identical teeth 5 formed on other cutting ribs 4. In general, thanks to all of its cutting ribs 4 having a “saw-like” appearance, the cutting thread 2 has a high cutting ability.

Figure 2, in which the corresponding elements are denoted by the same numerical positions, shows another variant of this cutting thread. On the longitudinal cutting ribs 4, teeth 5 are formed here, identical in shape and height, but with a rounded convex profile, having the form of round tablets that follow one after the other along the length of each cutting edge 4.

Figure 3 shows another embodiment of the cutting thread 2 according to the invention. On this thread 2 having the same central core shape, triangular-shaped teeth 5 are formed on the longitudinal cutting ribs 4 and are identical in shape and height.

Figure 4 shows another embodiment of the cutting thread 2 as an object of the invention. On this thread 2 having the same shape of the central core, an undulation 6 is formed on the longitudinal cutting ribs 4, which is repeated in the longitudinal direction of the aforementioned cutting ribs 4. In the example of FIG. 4, the undulation is relatively pronounced.

Another embodiment of the last cutting thread 2 is shown in FIG. The longitudinal cutting ribs 4 here have a less pronounced undulation 6, which also repeats in the longitudinal direction of the aforementioned cutting ribs 4.

Figure 6 shows a special form of execution of the cutting thread 2 having the same base shape. In this case, the teeth in order to improve the cutting ability of the yarn 2 have slots or depressions 7, which are repeated at regular intervals on each longitudinal cutting edge 4.

As shown in Fig. 7, tooth-like formations made on the longitudinal cutting ribs 4 of the cutting thread 2 may include teeth 5a of a higher height, between which other teeth 5b of a lower height are formed, with all teeth 5a and 5b having a triangular shape and a pattern formed with these teeth 5a and 5b, repeated with a predetermined pitch P along the length of each cutting edge 4.

Finally, as shown in FIG. 8, the teeth 5 can follow each other with a predetermined pitch P along the cutting thread 2, while they are separated from one another by a smooth surface free of teeth. This implementation method is applicable, in particular, for the teeth 5, formed not on the longitudinal cutting ribs 4 of the cutting thread 2, but outside the cutting ribs, directly on the outer surface of this thread 2.

It does not seem to go beyond the scope of the invention (as defined in the attached claims):

- the implementation of the cutting thread of any section and any size;

- the implementation of this cutting thread from any materials, simple or composites;

- the implementation of a larger or smaller number of cutting ribs equipped with formations such as teeth or similar formations;

- placement of formations such as teeth or similar formations not on possible cutting ribs, but on the outer surface of the cutting thread;

- the implementation of these formations such as teeth or similar formations with parts of various shapes;

- obtaining the aforementioned formations such as teeth or similar formations by any suitable means.

Claims (9)

1. A cutting thread for a brush cutter and a lawn mower, containing a central core of circular cross section (page 4) and at least one cutting edge located in the outer or peripheral part of the thread (page 6, paragraph 2 above), with each cutting edge contains teeth formed on each longitudinal cutting edge of the thread. 2. The cutting thread according to claim 1, containing a central core of circular cross section and four longitudinal cutting ribs located crosswise (page 4). 3. The cutting thread according to claim 1, in which each longitudinal cutting edge contains teeth, one after the other along the length of this cutting rib. 4. The cutting thread according to claim 3, in which the teeth are the same on all cutting edges, but are located on one cutting edge with a shift in the longitudinal direction with respect to the other. 5. The cutting thread according to claim 3, in which the cutting teeth are different on different cutting ribs. 6. The cutting thread according to any one of claims 1 to 4, in which all cutting teeth have the same shape and height. 7. The cutting thread according to any one of claims 1 to 4, in which the cutting teeth have a different shape or height and can be repeated with different steps. 8. The cutting thread according to any one of claims 1 to 4, in which the cutting teeth have a convex or concave rounded profile. 9. The cutting thread according to any one of claims 1 to 4, containing undulation on said cutting ribs.

Images