JP3015745B2 - Brush cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a brush cutter used for mowing and the like, and more particularly to a bearing portion for rotatably supporting a transmission shaft in an operation pipe while reducing the weight of an operation rod. An object of the present invention is to provide a brush cutter capable of reliably preventing rotation.

[0002]

2. Description of the Related Art Conventionally, mowers have been widely used for efficient mowing. Conventionally known brush cutters have various configurations in detail, but are basically configured as shown in FIG. That is, a hollow cylindrical operating rod 1 made of a metal material such as an aluminum alloy, a cutting blade 2 rotatably provided at one end (lower right end in FIG. 7) of the operating rod 1, and an operating rod 1 And a prime mover 3 provided at the other end (upper left end of FIG. 7). The prime mover 3 is a power source described in the claims. Further, a transmission shaft, which is rotatably supported by at least one bearing portion (not shown) and allows the power of the motor 3 to be transmitted to the cutting blade 2, is inserted through the inside of the operation rod 1. Further, an operation handle 5 is fixed to an intermediate portion of the operation rod 1 by a mounting bracket 4 so that an operator can grip the operation handle 5 to operate the operation rod 1 freely. The prime mover 3 is provided with a recoil starter 7 having a starter knob 6, and the prime mover 3 is started by operating (pulling) the starter knob 6.

A bearing portion for rotatably supporting the transmission shaft in the operating rod 1 includes, for example, a cylindrical bush made of a slippery synthetic resin or the like, and a bush holder for fitting the bush internally. Are widely used. The bush holder has an outer peripheral surface having a circular shape similar to the inner peripheral surface of the operating rod 1, and
It is press-fitted and fixed inside. When such a bearing portion is provided, a transmission shaft, a bush for internally fitting the transmission shaft,
The bush holder in which the bush is fitted and the operating rod 1 in which the bush holder is fitted are concentrically arranged. By providing such a bearing portion, at the time of rotation of the transmission shaft, the occurrence of vibration and abnormal noise is suppressed,
This transmission shaft can be smoothly rotated.

[0004] When performing a work such as mowing by using the above-described brush cutter, the operator attaches the brush cutter to the body by a belt 13 as shown in FIG. The prime mover 3 is started by pulling the starter knob 6 of the recoil starter 7. Thereby, the driving force of the prime mover 3 is transmitted to the cutting blade 2 via the transmission shaft, and the cutting blade 2 rotates. In this state, the operator performs the mowing operation while gripping the operation handle 5 and swinging (turning) the operating rod 1 left and right (in the direction of arrow A in FIG. 7 and the opposite direction). Such a bush cutter is applied to the cutting of weeds and lawns, and the cutting of trees.
In this specification, the operating direction of the operating rod 1 indicates the direction of the arrow A in FIG.

However, in the case of the conventional brush cutter described above, the operating rod 1 is formed in a hollow cylindrical shape, and has a relatively thick wall having the same thickness so as to withstand an impact force from all directions. Since the operating rod 1 is formed in a long shape, the weight is large, and therefore, there is a disadvantage that the weight of the brush cutter is increased. Further, the following disadvantages also exist due to the bearing portion for rotatably supporting the transmission shaft and the cross-sectional shape of the operating rod 1. That is, by incorporating the above-described bearing portion, the transmission shaft, the bush, the bush holder, and the operating rod 1 are concentric with each other. Although the bush holder is press-fitted and fixed in the operating rod 1, the bush holder may be rotated in the circumferential direction by rotation of the transmission shaft with use of the brush cutter. In such a case, the transmission shaft cannot efficiently transmit the driving force of the prime mover 3 to the cutting blade 2.

In order to solve the former inconvenience, for example, Japanese Patent Publication No. 2-4249 discloses that, as shown in FIG. 8, an inner side of an operating rod 1a extends radially in an axial direction (front and back directions in FIG. 8). A very long rib 8 is formed, and a bearing tube 10a for supporting a transmission shaft 9a is provided at the center of the rib 8.

[0007] In order to solve the latter inconvenience, Shokai Shokai 6
In Japanese Patent Application Laid-Open No. 1-64227, as shown in FIG. 9, the cross-sectional shape of the operating rod 1b is made uneven, and the rotation of the bearing portion is prevented by using the unevenness formed on the inner peripheral surface of the operating rod 1b. Configuration is described.

[0008]

However, the techniques described in the above publications have the following disadvantages. First, in the case of the structure of the first conventional example shown in FIG. 8, the ribs 8 are provided radially and continuously over the entire axial direction of the operating rod 1a.
It is inevitable that the weight of the entire operation rod 1a increases with the formation of the rib 8. Further, since the bearing pipe 10a is also provided continuously over the entire axial direction of the operating rod 1a, the weight of the brush cutter is increased. As a result, in the case of the structure of the above-mentioned first conventional example, the weight cannot be reduced. Mowing and mowing work using a mower is labor intensive,
In particular, in recent years, the elderly are often involved in such mowing work, and it is a considerable labor burden to work for a long time with a heavy mowing machine in an unreasonable posture. Therefore,
In the case of the structure of the first conventional example described above, which causes an increase in the weight of the entire operation rod, it is not preferable. Further, the formation of such ribs 8 causes an increase in the number of constituent materials and an increase in labor for manufacturing, and increases the manufacturing cost.

In the case of the structure of the second conventional example shown in FIG. 9, an irregular shape also appears on the outer peripheral side of the operating rod 1b. When the uneven shape is formed on the outer peripheral side of the operating rod 1b in this way, when the brush cutter is used, cutting grass, twigs and the like may fit into the concave portions, and the twigs and the like may be caught on the convex portions. It will hinder you. In order to work smoothly,
The presence of such uneven portions is not preferable.

[0010] The brush cutter according to the present invention eliminates any of the above-mentioned inconveniences, ensures that the bearing is prevented from rotating, and
The inventor of the present invention has invented to provide an inexpensive brush cutter that does not increase the weight of the brush cutter as a whole and does not hinder a smooth operation due to the provision of the rotation preventing structure.

[0011]

The brush cutter according to the present invention is, like the conventional brush cutter described above, provided with an operating rod having a hollow cylindrical shape and a perfect circular outer peripheral shape, and rotatably provided at one end of the operating rod. Cutting blade, a power source provided at the other end of the operating rod, and inserted into the operating rod while being rotatably supported by at least one bearing portion, and transmitting the rotational force of the power source to the cutting blade. And a free transmission shaft. In particular, in the brush cutter of the present invention, the thickness of the cross section of at least the bearing portion installation portion of the operating rod is made non-uniform. At the same time, the outer peripheral shape of the bearing portion matches the inner peripheral surface shape of the bearing portion installation portion of the operating rod. Then, by fitting the bearing portion inside the operating rod, the bearing portion is prevented from rotating in the circumferential direction.

The specific shape of the cross section of the operating rod may be an uneven shape as described in claim 2, or the operating rod may be used when the brush cutter is used as described in claim 3. The operation direction and the opposite direction may have an oval shape with a short diameter, or as described in claim 4, a true circle eccentric to the rear in the operation direction of the operation rod when the brush cutter is used.

[0013]

The operation of the mower of the present invention configured as described above, such as mowing, is the same as that of the conventional mower described above. That is, the operator performs the mowing operation while gripping the operation handle and swinging (rotating) the operation rod left and right. In particular, in the case of the brush cutter of the present invention,
The cross-sectional shape of at least the bearing portion installation portion of the operating rod, the uneven shape, the elliptical shape, the eccentric true circle and the like, the thickness thereof is not uniform, and the outer peripheral shape of the bearing portion is the cross-sectional shape. It has a matching shape. Therefore, when the bearing portion is assembled in the operation punch, the bearing portion is reliably prevented from rotating in the circumferential direction.

Moreover, by making the cross-sectional shape of the bearing installation portion of the operating rod non-uniform, the strength of the operating rod is improved. For example, it is known that the strength of the operating rod is improved when the cross-sectional shape of the operating rod is uneven.
That is, the same strength as in the related art can be obtained, and the thickness of a part of the operating rod can be reduced, so that the weight of the operating rod can be reduced. Further, the cross-sectional shape may be an elliptical shape in which the operating direction of the operating rod when the brush cutter is used and the opposite direction thereof are short diameters, or a true eccentric rearward in the operating direction of the operating rod when the brush cutter is used. In the case of a circular shape, in operation, the front side in the operating direction of the operating rod, which is a part to which a force such as an impact force is applied, is thick, so that the strength of the part is increased, and the other parts are Can also be thin. Therefore, the brush cutter of the present invention can reduce the weight of the operating rod.

Further, in the brush cutter according to the present invention, the outer diameter portion of the operating rod has a perfect circular cross section. For this reason, when using the brush cutter of the present invention, twigs and the like do not get caught on the operating rod, and the work is not hindered. Therefore, work can be performed smoothly.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a brush cutter according to the present invention will be described with reference to the drawings. 1 and 2
A first example of an embodiment of the present invention corresponding to claim 2 is shown. The same parts as those in the conventional structure described above are denoted by the same reference numerals, and redundant description will be omitted or simplified. Hereinafter, description will be made focusing on features of the present invention. In the brush cutter in this example, the outer peripheral shape of the operating rod 1 is a perfect circle or a substantially perfect circle. A bearing portion 12 composed of a bush 10 and a bush holder 11 is provided inside the operating rod 1.
And the transmission shaft 9 is inserted therethrough. At least a section of the operating rod 1 where the bearing portion 12 is installed is formed with irregularities in the circumferential direction. Further, the outer peripheral shape of the bearing portion 12 matches the inner peripheral shape of the cross section of the operating rod 1 so that the bearing portion 12 can be freely fitted to the corresponding portion. That is, the concave portion and the convex portion on the inner peripheral surface of the operating rod 1 and the convex portion and the concave portion on the outer peripheral surface of the bearing portion 12 are assembled in a state of being fitted respectively. This prevents the bearing 12 from rotating in the circumferential direction.

The operation at the time of mowing or the like using the brush cutter of the present embodiment configured as described above is the same as that of the conventional brush cutter described above. That is, the operator performs the mowing operation while gripping the operation handle 4 and swinging the operation rod 1 left and right (in the direction of arrow A in FIG. 7 and the opposite direction). In particular, in the case of the brush cutter of the present embodiment, at least the section of the operating rod 1 where the bearing portion 12 is installed is made uneven, and the outer peripheral surface of the bearing portion 12 is fitted to the inner peripheral surface of the operating rod 1. Since the bearings 12 are formed in a freely adaptable shape, it is ensured that the bearing 12 rotates in the circumferential direction.

In addition, since the inner peripheral shape of the operating rod 1 is made uneven, the strength of the operating rod 1 particularly in the diametrical direction is improved. Therefore, the brush cutter according to the present embodiment can reduce the thickness of the conventional operation rod 1 particularly in the concave portion, and can reduce the weight of the operation rod 1.

Further, in the brush cutter according to the present embodiment, the outer peripheral surface of the operating rod 1 has a perfect circular shape or a substantially perfect circular shape. For this reason, when the brush cutter is used, the twigs and the like move the operating rod 1.
The work is not hindered by being caught on the surface. Therefore, work can be performed smoothly.

Next, FIG. 3 shows the structure of a second example of the embodiment of the brush cutter according to the present invention.
In the case of the structure of this example, the concave and convex shape of the operation rod 1 is provided on both sides in the operation direction A of the operation rod 1 and the opposite direction (the left-right direction when used). That is, when the work is performed using the brush cutter, a force such as an impact is particularly applied on the front side (the back side in FIG. 7) of the operation rod 1 in the operation direction A due to the brush cutter operation. When the operating rod 1 is used, a large impact force is not applied to the vertical direction and the rear side in the operating direction (the front side in FIG. 7). For this reason, in the present embodiment, a pair of convex portions and a concave portion formed by the convex portions are provided on both sides of the operating rod 1 in the operation direction A and the opposite direction.
Although not shown, the outer peripheral surface of the bearing portion 12 is
A projection is formed that fits into the recess formed between the pair of projections. The inner peripheral surface of the operating rod 1 and the outer peripheral surface of the bearing portion 12 are formed by fitting the concave portion and the convex portion formed on the operating rod 1 with the convex portion and the concave portion formed on the bearing portion 12, respectively. Assemble in the state. This prevents the bearing 12 from rotating in the circumferential direction. Other configurations and operations are the same as those of the above-described first example.

In the structure of the second example, the bearing 12
As in the case of the first example, an uneven portion may be formed on the outer peripheral surface over the entire circumference in the circumferential direction. In this case, any one of the protrusions may be fitted into the recess between the pair of protrusions formed on the inner peripheral surface of the operation rod 1, so that the assembling operation is facilitated.

Next, FIG. 4 shows a structure of a third embodiment of the present invention corresponding to claim 2. In the case of the structure of this example, the uneven shape of the inner peripheral surface of the operating rod 1 is provided only on the front side in the operating direction A of the operating rod 1. That is, the operating direction A of the operating rod 1
Is provided with a pair of convex portions and a concave portion formed by the convex portions. This is because, as described above, when working with a brush cutter, a force such as an impact is particularly applied.
This is due to the front side in the operation direction of the operation rod. This allows
The strength of the front portion in the operation direction is improved, and the bearing 12 is prevented from rotating. Other configurations and operations have been described above, including that the concavo-convex shape formed on the outer peripheral surface of the bearing portion 12 may be provided on a part of the outer peripheral surface or over the entire circumference in the circumferential direction. This is the same as the structure of the second example.

Next, FIG. 5 shows a structure of a fourth embodiment of the present invention corresponding to claim 3. In the case of the structure of this example, the cross-sectional shape of at least the bearing portion 12 installation portion of the operating rod 1 is such that the operating direction A of the operating rod 1 when the brush cutter is used and the opposite direction thereof have a short diameter, and the vertical direction has a long diameter. It has an elliptical shape, that is, an elliptical shape. On the other hand, the outer peripheral surface of the bearing portion 12 has substantially the same shape as the inner peripheral surface of the operating rod 1. When assembling the bearing portion 12 into the operating rod 1,
It is only necessary to simply press-fit the bearing portion 12 into the operating rod 1. With the configuration as described above, the rotation of the bearing portion 12 and the improvement of the strength of the operating rod 1 are compatible. In particular, in this example, when the work is performed using the brush cutter, both sides including the front side in the operation direction A of the operation rod 1 to which a force such as an impact is applied are thickened. improves. Accordingly, the thickness of the conventional operating rod 1 can be partially reduced, and the weight of the operating rod 1 can be reduced.

FIG. 6 shows the structure of a fifth embodiment of the present invention, which corresponds to claim 4. In the case of the structure of this example, the cross-sectional shape of at least the bearing portion 12 installation portion of the operation rod 1 is a true circle eccentric to the rear of the operation direction A of the operation rod 1 when the brush cutter is used. On the other hand, the outer peripheral surface of the bearing portion 12 has a circular shape substantially similar to the inner peripheral surface shape of the operating rod 1. When assembling the bearing portion 12 into the operating rod 1, it is sufficient to simply press-fit the bearing portion 12 into the operating rod 1. With the configuration described above, the bearing 12
And the weight of the operating rod 1 is compatible. In particular,
In the case of this example, when the work is performed using the brush cutter, since the front side in the operation direction A of the operation rod 1 to which a force such as an impact is applied is particularly thick, the other parts can be made thin. ,
The weight of the operating rod 1 can be reduced.

That is, in each of the above-described examples, the cross-sectional shape of the operating rod 1 is made nonuniform as described above, but this is achieved by removing the thickness of the members constituting the operating rod 1. Do. As a result, the operating rod constituting the brush cutter according to the present invention is lighter in weight than the conventional one. Moreover, the cross-sectional shape is uneven (in the case of the first example).
By doing so, at least the same strength as that of the related art or higher can be obtained. Therefore, such a configuration can be applied to, for example, an operation handle to reduce the weight and strength of the operation handle.

[0026]

The brush cutter according to the present invention is constructed and operated as described above, so that the rotation of the bearing portion can be surely prevented, the weight of the entire brush cutter can be reduced, and the brush cutter can be operated smoothly. Can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line BB of FIG. 2, showing a structure of a first example of an embodiment of the present invention;

FIG. 2 is a sectional view taken along the line CC of FIG. 1;

FIG. 3 is a sectional view of a part equivalent to FIG. 2, showing a structure of a second example of the embodiment of the present invention;

FIG. 4 is a cross-sectional view of the same portion as FIG. 2, showing the structure of the third example.

FIG. 5 is a sectional view of a portion equivalent to FIG. 2, showing the structure of the fourth example.

FIG. 6 is a cross-sectional view of a portion equivalent to that of FIG. 2, showing the structure of the fifth example.

FIG. 7 is a perspective view showing a use state of the brush cutter.

FIG. 8 is a cross-sectional view of the same portion as FIG. 2, showing the structure of the first conventional example.

FIG. 9 is a cross-sectional view of the same portion as FIG. 2, showing the structure of the second conventional example without the bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Operating rod 2 Cutting blade 3 Prime mover 9 Transmission shaft 12 Bearing part

Claims (4)

(57) [Claims] An operating rod (1) having a hollow cylindrical shape and a perfect circular outer shape, a cutting blade (2) rotatably provided at one end of the operating rod (1), and the operating rod (1). And a power source (3) provided at the other end of the power source (3) and inserted through the operating rod (1) in a state of being rotatably supported by at least one bearing portion (12). In a brush cutter provided with a transmission shaft (9) that can be freely transmitted to the cutting blade (2), the thickness of the cross section of at least the bearing (12) installation portion of the operating rod (1) is made non-uniform, The bearing (1)
The outer shape of 2) is matched with the inner circumferential surface of the bearing (12) installation portion of the operating rod (1), and this bearing (12) is fitted inside the operating rod (1). A brush cutter characterized in that the bearing (12) is prevented from rotating in the circumferential direction. 2. The operating punch (1) having at least a bearing portion (1).
2) By making the cross-sectional shape of the installation part uneven,
The brush cutter according to claim 1, wherein the section has a non-uniform thickness. 3. The operating rod (1) has at least a bearing (1).
2) By setting the cross-sectional shape of the installation portion to an elliptical shape in which the operating direction (A) of the operating rod (1) when the brush cutter is used and the opposite direction are short diameters, the cross-sectional thickness of the portion 3. The brush cutter according to claim 1, wherein 4. At least a bearing portion (1) of the operating rod (1).
2) By setting the cross-sectional shape of the installation portion to be a perfect circle eccentric to the rear side in the operation direction (A) of the operating rod (1) when the brush cutter is used, the thickness of the cross-section of the portion is not uniform. The brush cutter according to claim 1, wherein: