JP3230448U - Rotary blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary blade capable of effectively preventing vine wrapping and easy to manufacture. SOLUTION: A rotary blade 1 has a plurality of saw blades 3 arranged on the outer peripheral edge of a disk-shaped base plate 2, and a shaft hole 4 at the center of rotation of the rotary blade 1 and engaged with a drive shaft. It is used by attaching it to a brush cutter. The rotary blade 1 is characterized in that a groove portion 5 which is cut open from the tooth bottom of the saw blade 3 and recesses toward the shaft hole 4 is formed at at least one place. [Selection diagram] Fig. 1

Description

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

A brush cutter is a device that a worker holds to mow weeds and the like. For example, as shown in Patent Document 1 and the like, a general brush cutter is configured to include an engine and a transmission unit at both ends of a control stick. A rotary blade is attached to the transmission unit, and the rotary blade is rotationally driven by the engine. The operator operates the operation stick and hits the rotary blade against the weeds or the like to mow the weeds or the like.

For example, as shown in Patent Document 2 and the like, a general rotary blade includes a plurality of saw blades arranged on the outer peripheral edge of a disk-shaped steel base plate and a drive of a transmission unit at the center of rotation. It has a shaft hole that engages with the shaft. In short, the rotary blade is a kind of rotary saw, and when the rotary saw blade hits a leaf or stem of a weed or the like, the leaf or stem is cut.

According to the brush cutter, weeds and the like can be removed much more efficiently than when a mowing sickle is used. Further, since the brush cutter is carried by an operator, weeds and the like can be removed even in a narrow area or a sloping area where vehicles cannot enter.

However, some weeds are not easy to cut. In particular, the vines of Cayratia japonicum and debris are strong and often fail to cut. The vine that fails to cut may get caught in the saw blade and wind around the drive shaft of the rotary blade unit. In addition, since the vines of waste are long and the long ones are 10 m or more, a large load is applied to the engine when the vines wind around the drive shaft of the rotary blade unit. As a result, the engine stops. Further, the vine wound around the drive shaft is not easy to remove because it bites into the narrow gap between the rotary blade and the rotary blade unit.

Therefore, many inventions have already been published for the purpose of suppressing the wrapping of the vine around the drive shaft. For example, in the rotary blade described in Patent Document 2, a cylindrical wrapping prevention member is fixed to the upper surface of the base plate, and the drive shaft of the rotary blade unit is surrounded by the wrapping prevention member. In the rotary blade described in Patent Document 3, an exclusion body having an inclined surface having a lower front surface and a higher rear surface in the rotation direction of the rotary blade is fastened to a portion of the upper surface of the base plate close to the saw blade. ..

Registered Utility Model No. 3208014 JP-A-2015-226259 Japanese Unexamined Patent Publication No. 9-322627

Since the rotary blade described in Patent Document 2 includes a wrapping prevention member that surrounds the outer circumference of the drive shaft, the vine does not wrap around the drive shaft. However, since the vines are still entangled with the brush cutter, it is necessary to stop the brush cutter and remove the vines every time the vines wrap around the wrapping prevention member.

Since the rotary blade described in Patent Document 3 cuts the vine with an exclusion body attached to the base plate, the vine does not wind around the drive shaft. However, there is a problem that the exclusion body retrofitted to the base plate is easily detached from the base plate. If the exclusion body comes off the base plate during the rotation of the rotary blade, it may be repelled by centrifugal force and scattered in an unexpected place.

Further, each of the rotary blades described in Patent Document 2 and Patent Document 3 has a problem that it takes time and effort to manufacture and the manufacturing cost increases because a separate part is attached to the base plate afterwards.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotary blade that can effectively prevent vines from wrapping around and that is easy to manufacture.

In order to achieve the above object, the rotary blade according to the present invention is engaged with a plurality of saw blades arranged on the outer peripheral edge of a disk-shaped base plate and a drive shaft at the center of rotation of the rotary blade. In a rotary blade that has a shaft hole and is used by attaching it to a mowing machine, a groove that is cut from the tooth bottom of the saw blade and recesses toward the shaft hole is formed at at least one place. is there.

The rotary blade may include a plurality of grooves. A plurality of grooves may be arranged at equal intervals radially with respect to the center of rotation. The rotary blade may be provided with four grooves, and the radius connecting each groove and the center of rotation may be arranged at a central angle of 90 ° at a pitch.

The rotary blade may have a cutting edge formed on an edge located behind the rotary blade in the rotational direction with the groove of the base plate interposed therebetween. The base plate is bent in the out-of-plane direction at least in part, and when the rotary blade is attached to the brush cutter and used, the edge located forward in the rotational direction of the rotary blade across the groove of the base plate is It may be located farther from the ground than the edge located rearward in the rotation direction of the rotary blade of the base plate.

According to the present invention, since the rotary blade is provided with a groove portion that is cut open from the tooth bottom of the saw blade and recesses toward the center of rotation of the rotary blade, the vine that the saw blade fails to cut is guided to the groove portion and there. Be disconnected. Even if the vine is not cut in the groove, the vine will not cross the groove and approach the drive shaft. Therefore, the vine is effectively prevented from wrapping around the drive shaft.

Further, according to the present invention, since the groove portion is formed by cutting a part of the base plate, it is not necessary to retrofit a separate part to the base plate when manufacturing the rotary blade according to the present invention. Therefore, the rotary blade according to the present invention can be manufactured at low cost because the labor required for manufacturing is small.

It is a top view of the rotary blade which concerns on embodiment of this invention. FIG. 5 is a cross-sectional view showing the rotary blade shown in FIG. 1 cut along a plane indicated by the line AA'in FIG. It is a top view of the rotary blade described in FIG. 1, and is the figure which shows the operation of the rotary blade in chronological order. 3 (C) is a cross-sectional view showing the rotary blade shown in FIG. 3 (C) cut along the plane shown by the BB'line in FIG. 3 (C). It is a top view of the rotary blade shown in FIG. 1, and is a diagram showing another action of the rotary blade in chronological order. 5 (B) is a cross-sectional view showing the rotary blade shown in FIG. 5 (B) cut along the plane shown by the CC'line in FIG. 5 (B).

FIG. 1 is a plan view of the rotary blade 1 according to the embodiment of the present invention as viewed from above. As shown in FIG. 1, the rotary blade 1 is configured to include a large number of saw blades 3 on a disc-shaped steel base plate 2. The saw blades 3 are arranged at equal intervals on the outer peripheral edge of the base plate 2. At the center of the base plate 2, a shaft hole 4 (not shown) that is engaged with a drive shaft of a brush cutter is provided. The rotary blade 1 is driven by a brush cutter and rotates in the direction indicated by the arrow in FIG. That is, the rotary blade rotates counterclockwise around the center O of one rotation to cut weeds and the like (not shown).

As shown in FIG. 1, the rotary blade 1 is formed with groove portions 5 at four locations. The groove portion 5 is cut open from the tooth bottom of the saw blade 3 and is recessed toward the rotation center O of the rotary blade 1. Further, the groove portions 5 are arranged at equal intervals radially with respect to the rotation center O of the rotary blade 1. In the present embodiment, the groove portions 5 are arranged so that the radii connecting the groove portion 5 and the rotation center O of the rotary blade 1 are arranged at a central angle of 90 ° pitch. Further, a cutting blade 7 is formed on the edge 6 of the base plate 2 located behind the rotary blade 1 in the rotational direction with the groove portion 5 interposed therebetween.

In this embodiment, the outer diameter (diameter) D of the rotary blade 1 is 255 mm. In this case, the recessed depth d measured from the outer edge of the rotary blade 1 of the groove portion 5 is set to about 50 mm. Further, the width W of the groove portion 5 is set to about 3 mm.

FIG. 2 is a cross-sectional view showing the rotary blade 1 shown in FIG. 1 cut along a plane indicated by the line AA'in FIG. As shown in FIG. 2, the base plate 2 of the rotary blade 1 is partially bent in the out-of-plane direction, and the edge 6 of the base plate 2 located behind the rotary blade 1 in the rotational direction across the groove 5 is A step is formed between the edge 8 of the base plate 2 located in front of the rotary blade 1 in the rotation direction with the groove portion 5 interposed therebetween. When the rotary blade 1 is attached to the brush cutter for use, the ground is in the direction indicated by the arrow in FIG. Therefore, when the rotary blade 1 is attached to the brush cutter and used, the edge 8 is located farther from the ground than the edge 6. In the present embodiment, the height H of the step between the edge 8 and the edge 6 is set to about 5 mm. Further, the cutting edge 7 is ground so that its tip has an acute angle in cross-sectional shape.

Here, the operation of the rotary blade 1 will be described with reference to FIGS. 3 (A) to 3 (C) and FIG. 3 (A) to 3 (C) are plan views of the rotary blade 1 as viewed from above, and are views showing the action of the rotary blade in chronological order. FIG. 4 is a cross-sectional view showing the rotary blade 1 shown in FIG. 3 (C) cut along the plane shown by the BB'line in FIG. 3 (C).

Here, as shown in FIG. 3A, when one of the saw blades 3 of the rotary blade 1 caught the vine 9, but the vine 9 could not be cut, the vine 9 that could not be cut was the rotary blade 1. It is assumed that it is placed on the upper surface of. In this case, when the rotary blade 1 rotates in the rotational direction, as shown in FIG. 3 (B), the tip of the vine 9 is pulled by the saw blade 3 and moves to the left in the figure. At the same time, the groove portion 5a moves to the right in the figure. As a result, the vine 9 is guided to the entrance of the groove 5a. When the rotary blade 1 further rotates in the rotational direction, the vine 9 is captured by the groove portion 5a of the rotary blade 1 as shown in FIG. 3C. When the vine 9 is captured by the groove 5a, the movement of the vine 9 in the drive axis direction (not shown) is stopped by the groove 5a. As a result, the vine 9 is prevented from wrapping around the drive shaft. Further, when the vine 9 is caught by the groove portion 5a, as shown in FIG. 4, the vine 9 hangs down from the upper surface of the rotary blade 1 through the groove portion 5a to the lower side of the rotary blade 1 and comes into contact with the cutting blade 7.

Then, in the states shown in FIGS. 3C and 4, when a brush cutter (not shown) is swung around to move the rotary blade 1 in the direction indicated by the arrow P in FIG. 3C, the vine 9 is formed by the cutting blade 7. Be disconnected. The residue of the vine 9 remaining on the upper surface of the rotary blade 1 is repelled by centrifugal force and removed from the rotary blade 1.

Next, another operation of the rotary blade 1 will be described with reference to FIGS. 5 (A) and 5 (B) and FIG. 5 (A) and 5 (B) are plan views of the rotary blade 1 as viewed from above, and are views showing another operation of the rotary blade in chronological order. FIG. 6 is a cross-sectional view showing the rotary blade 1 shown in FIG. 5 (C) cut along the plane shown by the CC'line in FIG. 5 (B).

Here, as shown in FIG. 5A, when one of the saw blades 3 of the rotary blade 1 catches the vine 9 but cannot cut the vine 9, the vine 9 that could not be cut is the rotary blade 1. It is assumed that it is in contact with the lower surface. As shown in FIG. 2, there is a step between the edge 8 of the base plate 2 located in front of the rotary blade 1 in the rotation direction and the edge 6 of the base plate 2 located in the rear of the rotation direction across the groove 5. The edge 8 is higher than the edge 6. Therefore, in this case, when the rotary blade 1 rotates in the rotational direction, as shown in FIGS. 5B and 6, the vine 9 passes through the step between the edge 8 and the edge 6 in the groove 5b, and the rotary blade 1 is rotated. Move to the upper surface of 1. When the rotary blade 1 further rotates in the rotational direction, the vine 9 is captured in the groove 5c of the rotary blade 1 through a process similar to the process described above with reference to FIGS. 3 (B) and 3 (C) and FIG. It is cut by the cutting blade 7.

As described above, since the rotary blade 1 includes the groove portion 5, even if the saw blade 3 catches the vine 9 but cannot cut the vine 9, the vine 9 is caught in the groove portion 5, so that the vine 9 is caught. It does not wrap around the drive shaft. Further, the vine 9 caught in the groove 5 is cut by the cutting blade 7. As described above, according to the rotary blade 1, the winding of the vine 9 around the drive shaft is prevented. Further, since the rotary blade 1 can be manufactured by simply adding a simple process to the existing rotary blade, it can be manufactured at low cost.

The technical scope of the present invention is not limited depending on the above-described embodiment. The present invention can be freely applied, modified or improved within the scope of the technical idea described in the utility model registration claims.

In the above embodiment, the example in which the rotary blade 1 includes four groove portions 5 is shown, but the groove portions 5 included in the rotary blade 1 are not limited to four. The rotary blade 1 may include 5 or 6 or more groove portions 5. The rotary blade 1 may include three or two groove portions 5. The rotary blade 1 may include only one groove 5.

In the above embodiment, specific numerical values have been exemplified for the dimensions of the groove portion 5, but the technical scope of the present invention is not limited by the exemplified numerical values. The width W of the groove 5 and the height H of the step between the edge 8 and the edge 6 are determined based on the diameter of the cross section of the vine 9 to be cut by the rotary blade 1. The width W and the height H may be any one obtained by adding a slight margin to the diameter of the cross section of the vine 9. The recessed depth d measured from the outer edge of the rotary blade 1 of the groove portion 5 is required to have a dimension such that the vine 9 caught in the groove portion 5 does not easily come off. Good results can be obtained if the recessing depth d is selected in the range of about 20% to 13% of the outer diameter (diameter) D of the rotary blade 1. For example, when the outer diameter (diameter) D of the rotary blade 1 is 230 mm, the recessing depth d may be 30 mm.

The mechanical configuration of the rotary blade 1 shown above, particularly the shapes of the base plate 2 and the saw blade 3, is an example, and the technical scope of the present invention is not limited by the exemplified mechanical configuration. For example, the base plate 2 may be provided with holes for weight reduction and heat dissipation promotion. The shape and number of saw blades 3 can be arbitrarily selected. The material constituting the rotary blade 1 is also not limited.

1 rotary blade, 2 base plate, 3 saw blade, 4 shaft hole, 5,5a, 5b, 5c groove, 6,8 edge, 7 cutting blade, 9 vine

Claims (6)

Rotation used by attaching to a brush cutter with a plurality of saw blades arranged on the outer peripheral edge of a disk-shaped base plate and a shaft hole located at the center of rotation of the rotary blade and engaged with a drive shaft. On the blade
It is characterized in that a groove portion cut from the tooth bottom of the saw blade and recessed toward the shaft hole is formed at at least one place.
Rotary blade. It is characterized by having a plurality of the grooves.
The rotary blade according to claim 1. A plurality of the grooves are arranged at equal intervals radially with respect to the center of rotation.
The rotary blade according to claim 2. The four grooves are provided, and the radius connecting each groove and the center of rotation is arranged at a central angle of 90 ° at a pitch.
The rotary blade according to claim 3. A cutting edge is formed on an edge located rearward in the rotation direction of the rotary blade with the groove portion of the base plate interposed therebetween.
The rotary blade according to any one of claims 1 to 4. The base plate is bent in the out-of-plane direction at least in part.
When the rotary blade is attached to a brush cutter and used, the edge located forward in the rotation direction of the rotary blade across the groove portion of the base plate is rearward in the rotation direction of the rotary blade of the base plate. It is characterized by being farther from the ground than the edge on which it is located.
The rotary blade according to any one of claims 1 to 5.

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