JP4876144B2 - Brush blade - Google Patents

Description

  The present invention relates to a brush cutter blade that is used by being attached to a brush cutter.

Conventionally, various types of cutting blades have been proposed that are used by being attached to a brush cutter for cutting vegetation such as fields, forests, gardens, and fields.
For example, the brush blade of Patent Document 1 is a brush blade having a chip blade attached to the outer peripheral surface of a disk-shaped substrate, and the chip blade is attached to a tooth portion protruding along the outer peripheral surface of the substrate. Configured.

JP 10-42653 A

However, the conventional cutting blade is suitable for cutting off vegetation, but if pebbles are mixed in the grass, the pebbles bounce off the teeth and scatter them around at high speed, and It was dangerous to hurt or hit people.
Therefore, when the present inventor made a variety of experiments by cutting the cutting blade from the outer peripheral surface of the substrate so as to reduce the unevenness, the inventor can reduce the risk of scattering pebbles. However, the wind pressure in the radial direction is generated in the vicinity of the tooth part with the rotation of the cutting blade, and the thin and soft grass oscillates and escapes even with this small wind pressure, and cuts the thin and flexible grass. I found another problem that I couldn't do it.

  Accordingly, an object of the present invention is to provide a cutting blade that can safely cut even thin and flexible grass without scattering pebbles.

  Accordingly, the brush cutting blade according to the present invention includes a cemented carbide tip blade that protrudes from the outer peripheral edge portion of the disc-shaped substrate and is disposed at the same pitch along the outer peripheral edge portion of the substrate. In the brush cutting blade, a substantially semicircular arc-shaped grass drawing slit is cut out at the outer peripheral edge of the substrate, with the upstream side surface of the tip blade as a starting end.

The slit has a substantially semicircular arc shape centering around the side surface of the tip blade, and a corner between the slit and the outer peripheral edge constitutes a predetermined acute pebble intrusion prevention corner. It is what .

Further, the end center line of the slit is inclined with a predetermined acute end inclination angle in the counter-rotating direction with respect to the radial line of the substrate .

In addition, the slit has a groove width from the end portion to the pebbles intrusion prevention corner portion set to 1.5 mm to 3.0 mm, and the outside from the pebbles intrusion prevention corner portion to the start end portion. The opening width of the opening is set to a size 1.3 to 2.0 times the groove width .

  According to the brush blade of the present invention, it is a case where pebbles are prevented from flying, scratches such as automobiles and windows are prevented, the danger to the human body is reduced, and thin and flexible grass grows. But you can surely mow this.

It is the whole figure which showed one Embodiment of the brush cutting blade of this invention. It is the principal part enlarged view which showed the brush cutter blade. It is the principal part enlarged view which showed the brush cutter blade in detail. It is action | operation explanatory drawing of a brush cutting blade, Comprising: (a) is plane action explanatory drawing, (b) is a YY cross-section action explanatory drawing of (a).

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
1 to 3 are views showing a brush cutting blade 1 according to the present invention.
The brush cutting blade 1 is formed in a disk shape, and a cemented carbide tip blade 3 made of cemented carbide is brazed along the outer peripheral edge 2a of the substrate 2. The carbide tip blades 3 are arranged at the same pitch on the outer peripheral edge portion 2a, and the tip end portion 3a protrudes from the outer peripheral edge portion 2a. On the side surface 3b on the upstream side in the rotation direction F of the tip blade 3, a blade end 3c is formed near the tip 3a. A substantially semicircular arc-shaped grass drawing slit 10 is formed in the outer peripheral edge 2 a of the substrate 2 with the side surface 3 b of the tip blade 3 as the start end 12. The blade end portion 3c is exposed over a portion corresponding to the start end portion 12 of the grass drawing slit 10 and a radially outward portion.

Kusakokomi slit 10 is formed in a substantially semicircular shape centered O ₁ near side 3b. The corners of the slit 10 and the outer peripheral edge 2a constitute a pebble intrusion prevention corner 13 that forms a predetermined acute angle α. That is, the slit 10 has a substantially semicircular arc shape curved in a convex shape in the rotation direction F.
Center line of the substantially semi-circular slit 10 forms a virtual circle C _1, termination centerline 11A is a tangent of at imaginary circle C ₁ at the end 11 of the slit 10, the radial line 20 of the substrate 2 In contrast, it is inclined in the counter-rotating direction B with a predetermined acute inclination angle β. The slit 10 is formed with a predetermined groove width W from the end portion 11 to the pebbles intrusion prevention corner portion 13, and the dimension of the groove width W is set to 1.5 mm to 3.0 mm.

In addition, the slit 10 has an opening 14 that is open to the outside from the start end 12 to the pebble intrusion prevention corner 13. The opening width T of the opening 14 is set to a dimension 1.3 to 2.0 times the groove width W.
The center angle of the circular arc obtained by connecting the starting end 12 on the virtual circle C ₁ to the end portion 11 is formed at the center O ₁ is set to be smaller than 180 °.

Further, At a between the chip edge 3 and the chip blade 3 adjacent an outer peripheral edge portion 2a, the radial dimensional difference ΔR between the circumscribed circle C ₀ connecting the distal end portion 3a of the tip blade 3, excluding the slits 10 The average value calculated in this way is set to 2.0 mm to 4.0 mm.
Note that the radial dimension of the average value calculated by excluding the slits 10 in the radial dimensional difference [Delta] R, at between the chip edge 3 and the chip blade 3 adjacent an outer peripheral edge portion 2a with the circumscribed circle C ₀ The difference ΔR is an arithmetic average value of the radial direction difference ΔR calculated by measuring the difference ΔR a predetermined number of times n excluding the slit 10 and dividing the total of the measured values of the dimension difference ΔR by the measured number n.

Further, the grindstone relief portion 4 is formed in an inclined shape on the counter-rotation direction B side of the tip blade 3 on the outer peripheral edge 2 a of the substrate 2, and the grindstone can be applied to the tip blade 3.
The thickness dimension of the substrate 2 is set to 1.2 mm, and the thickness dimension of the tip blade 3 is set to 2.0 mm.

The usage method (action) of the brush cutter 1 of the present invention described above will be described.
The brush cutter blade 1 is used by being attached to the tip of a rod of a brush cutter for cutting vegetation.
As shown in FIGS. 1 to 3, the brush cutter 1 attached to the brush cutter cuts vegetation with a carbide tip blade 3 disposed on the outer peripheral edge 2 a of the substrate 2 while rotating in the rotation direction F. pay.

  The carbide tip blade 3 exposes the blade end portion 3c in the rotation direction F, and cuts off the vegetation by the rotation of the blade end portion 3c. At this time, even if the pebbles Z are in contact with the outer peripheral edge 2a of the substrate 2 and the cemented carbide tip blade 3, the radial dimension difference ΔR and the mouth width T are sufficiently small, and the groove width W is 1. The pebbles Z do not enter the 5 mm to 3.0 mm grass drawing slit 10 and the centrifugal force is small even though an external force is applied to the pebbles Z (as shown in FIG. 2). However, the pebbles Z are not scattered around.

As shown in FIG. 4, with the rotation of the brush cutting blade 1, an air flow S indicated by an arrow in the drawing is generated around the carbide tip blade 3. Some of the laminar flow S ₁ of the flow S flowing along the outer peripheral edge portion 2a is guided by the pebble intrusion prevention corner portion 13 is guided from the opening 14 in Kusakokomi slit 10. Slits 10, since the inclined substantially arcuate end portion 11 opposite to the rotational direction B, passing the laminar flow S ₁ to smoothly end portion 11.
In this way, Kusakokomi slit 10, when flowing a laminar flow S ₁ into the slit 10 in the laminar flow S ₂ through the outer layer flow S ₁ is, without being pushed outward, carbide inserts It passes through the blade end 3c of the blade 3.

The opening 14 of the slit 10, because it sets its mouth width T to 1.3 to 2.0 times the dimension of the groove width W of the slit laminar flow flowing along with laminar flow S ₁ S ₂ , S ₃ is pulled into the carbide tip blade 3 side.
Therefore, the cutting blade 1 can cut away the thin and flexible grass that swings with a small wind pressure without escaping outside by using the air flow S in the vicinity of the carbide tip blade 3 that accompanies the rotation. It is.
As shown in FIG. 4, a chamfered portion 21 (shown by a two-dot chain line in FIG. 4A) is formed at the end portion 11 of the slit 10 to form a sharp inner end corner portion 22. Thus, it is possible to prevent the thin grass that has entered the slit 10 from being cut (wound). The angle γ of the inner end corner portion 22 is preferably 30 ° to 50 °.

Moreover, between the adjacent chip blades 3 and the chip blades 3, the average value of the radial direction dimension difference ΔR is set to 2.0 mm to 4.0 mm, so that the grass drawing slit provided in the brush cutting blade 1 Ten actions are most effectively exhibited.
That is, if the average value of the radial direction difference ΔR is smaller than 2.0 mm, the cemented carbide tip blade 3 does not function sufficiently, and the ability of the brush cutting blade 1 to cut off the plants decreases.
On the other hand, if the average value of the radial dimension difference ΔR is larger than 4.0 mm, centrifugal force may be transmitted to the tip blade 3 from which the pebbles Z protrude greatly and may be scattered.

  As described above, the present invention provides a cemented carbide tip blade in which the tip end 3a protrudes from the outer peripheral edge 2a of the disc-like substrate 2 and is disposed at the same pitch along the outer peripheral edge 2a of the substrate 2. In the cutting blade provided with 3, a substantially semicircular arc-shaped grass drawing slit 10 is formed in the outer peripheral edge 2 a of the substrate 2 with the side surface 3 b on the upstream side of the tip blade 3 as the start end 12. Therefore, the vegetation can be safely cut without scattering the pebbles Z, and the thin and flexible grass that easily swings even with a small wind pressure can be surely cut off.

The slit 10 has a substantially semicircular around O ₁ a side 3b near the tip blade 3, the corner portions of the slit 10 and the outer peripheral edge portion 2a, pebble intrusion prevention corner of predetermined acute angle α 13 is configured, the pebbles Z are not allowed to enter the grass entrance slit 10 and the vegetation can be cut off safely.

  Further, since the terminal center line 11A of the slit 10 is inclined with respect to the radial line 20 of the substrate 2 in the counter-rotating direction B with a predetermined acute inclination angle β, the air flow accompanying the rotation of the brush cutting blade 1 is achieved. Can be used to surely cut thin and soft grass that grows on the grass.

  In addition, the slit 10 sets the groove width W from the end portion 11 to the pebbles intrusion prevention corner portion 13 to 1.5 mm to 3.0 mm, and extends from the pebbles intrusion prevention corner portion 13 to the start end portion 12. Since the mouth width T of the outwardly open opening 14 is set to a dimension 1.3 to 2.0 times the groove width W, the cutting blade 1 can be safely and without scattering the pebbles Z. By using the air flow accompanying the rotation of the plant, it is possible to surely cut the vegetation.

Further, an outer peripheral edge portion 2a of in the substrate 2 between the tip blade 3 and the tip blade 3 adjacent, radial dimensional difference ΔR between the circumscribed circle C ₀ connecting the distal end portion 3a of the tip blade 3, slits 10 Since the average value calculated by excluding the above is set to 2.0 mm to 4.0 mm, the vegetation can be cut off safely and reliably without scattering the pebbles Z.

2 Disc-shaped substrate 2a Peripheral edge 3 Carbide tip blade 3a Tip tip 3b Side face 10 Grass loading slit 11 Terminating part 11A Termination center line 12 Starting edge 13 Pebble intrusion prevention corner 14 Opening 20 Radial line B Anti-rotation Direction W Groove width T Port width O ₁ center C ₀ circumscribed circle α Predetermined angle β End inclination angle ΔR Radial dimension difference

Claims (4)

Chip tip (3a) protrudes from the outer peripheral edge (2a) of the disc-shaped substrate (2) and is disposed at the same pitch along the outer peripheral edge (2a) of the substrate (2). In the cutting blade with the tip blade (3),
With the upstream side surface (3b) of the tip blade (3) as a starting end (12), a substantially semicircular arc-shaped grass drawing slit (10) is formed in the outer peripheral edge (2a) of the substrate (2). A cutting blade characterized by forming a notch. The slit (10) has a substantially semicircular arc shape with the center (O ₁ ) near the side surface (3b) of the tip blade (3),
The brush blade according to claim 1, wherein a corner between the slit (10) and the outer peripheral edge (2a) constitutes a pebble intrusion prevention corner (13) having a predetermined acute angle (α).   The end center line (11A) of the slit (10) is inclined with a predetermined acute end inclination angle (β) in the counter-rotating direction (B) with respect to the radial line (20) of the substrate (2). Item 1. A brush cutter according to item 1 or 2. The slit (10) has a groove width (W) from 1.5 mm to 3.0 mm from the terminal end (11) to the pebbles entry prevention corner (13), and the pebbles entry prevention angle. The mouth width (T) of the outwardly open opening (14) from the portion (13) to the start end (12) is 1.3 to 2.0 times the groove width (W). The brush cutter blade according to claim 2 set.

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