JP2008182919A - Bush cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bush cutter enabling easy bush-cutting work even by an unskilled person by stably floating the outer circumference of the front side of a rotary cutter and a protection cover from the ground. <P>SOLUTION: A rotary cutter (6) having a number of edges (7) on the outer circumference is attached to the tip end of a rod (1) furnished with a motor; a non-rotating protection cover (11) is placed opposite to the lower face of the rotary cutter (6), and fixed teeth (12) are attached to the outer circumference of the protection cover (11) in a state facing the edges (7) of the rotary cutter (6). The bush cutter having the above structure has a ground contacting protrusion (13) protruding downward with gentle inclination and attached to the outer circumference of the protection cover (11) at the side of the straight shaft of the fixed teeth (12). The ground contacting protrusion (13) is formed by partly bending the base plate (11a) of the protection cover (11) downward. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brush cutter that attaches a rotary cutter to the tip of a cocoon having a motor (engine) and a rod-like handle, and operates the cocoon to cut weeds while rotating the rotary cutter with the motor.

  The conventional brush cutter was as follows. That is, a rotating cutter rotated by the engine and a disk-shaped protective cover that is locked to the side of the heel and non-rotated are superposed on top of each other at the tip of the heel having an engine and a rod-like handle, Is formed in a dish shape with the central portion protruding downward, and the outer peripheral portion is brought close to the outer peripheral portion of the rotary cutter, and fixed teeth facing the blade of the rotary cutter are formed on the outer peripheral portion. It was.

  In the conventional one, the fixed tooth and the rotary blade are lifted from the ground by a predetermined amount when the central portion of the protective cover comes into contact with the ground, and captures small-diameter weeds with the fixed teeth formed on the outer peripheral portion of the protective cover. Large pebbles and the like were discarded, and weeds captured by fixed teeth were cut with a rotary cutter.

However, in the above-mentioned conventional one, the central portion of the protective cover protrudes downward so that the fixed teeth on the outer peripheral portion are lifted from the ground. Therefore, the protective cover is inclined with respect to the ground around the central portion. Easily, if the inclination angle is increased, the fixed tooth on the traveling side facing downward bites into the ground or collides with pebbles, thereby preventing the traveling along the ground. For this reason, it is necessary to trim while adjusting the inclination angle of the protective cover with respect to the ground (inclination angle of the rotary cutter), which requires skill in the mowing work and increases the burden on the operator.
JP 2006-197900 A

  An object of the present invention is to obtain a new brush cutter that can easily perform a brush cutting operation even by an unskilled person by stably floating the outer peripheral portion on the traveling side of the rotary cutter and the protective cover from the ground. And

The present invention is configured as follows to achieve the above object. That is, the invention according to claim 1 is provided with a rotary cutter having a large number of blades on the outer peripheral portion at the front end portion of the scissors equipped with a motor, and a non-rotating protective cover faces the lower surface side of the rotary cutter. In the brush cutter in which the outer peripheral portion of the protective cover is provided with a fixed tooth facing the blade of the rotary cutter, the outer peripheral portion of the protective cover and toward the straight axis side of the fixed tooth, downward A grounding protrusion that protrudes with a gentle inclination is provided.
According to a second aspect of the present invention, the grounding protrusion is formed by locally bending the substrate of the protective cover downward.
According to a third aspect of the present invention, spacer protrusions are provided at a predetermined pitch in the circumferential direction on the outer peripheral portion of the rotary cutter or the protective cover so as to keep the distance between the blade of the rotary cutter and the fixed tooth of the protective cover at a specified value. Is.

In the invention according to claim 1, since the grounding protrusion is present on the outer peripheral portion of the protective cover, when the protective cover is inclined with respect to the ground, the traveling grounding protrusion facing downward contacts the ground, and the traveling side is fixed. Teeth will lift off the ground and not bite into the ground. For this reason, the mowing operation can be performed without paying attention to the inclination angle of the protective cover with respect to the ground (the inclination angle of the rotary cutter), and even an unskilled person can easily perform the mowing operation. become.
In the invention according to claim 2, since the grounding protrusion is formed by curving the substrate of the protective cover, the grounding protrusion can be obtained easily and inexpensively.
In the invention according to claim 3, since the spacer projection approaches the blade of the rotary cutter and the fixed tooth of the protective cover, even when a large load and impact are applied to both blades, the spacer projection reliably holds the distance between both blades, Damage due to the collision of the two blades can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, FIG. 1 is a sectional side view of a cutter head portion of a brush cutter according to an embodiment of the present invention, FIG. 2 is a plan view of a protective cover, FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 5 is a VV sectional view of FIG.

  In FIG. 1, reference numeral 1 denotes a bush of a brush cutter, and a motor (engine) and a bar handle are attached to the upper part. Reference numeral 2 denotes a cutter head attached to the tip of the ridge 1. The cutter head 2 is as follows. That is, a gear case 3 is attached to the tip of the flange 1, a cylindrical rotating shaft 4 is arranged vertically on the gear case 3 and is rotatably supported by a bearing 5, and an upper mounting flange is provided at the lower end of the rotating shaft 4. A rotating cutter 6 having a diameter of about 230 mm is integrally connected through 4a. Reference numeral 4b denotes a fixing screw for fixing the rotary cutter 6 to the upper mounting flange 4a.

  As shown in FIGS. 4 and 5, the rotary cutter 6 has twelve serrated blade bases 6 b in the circumferential direction on the outer periphery of a disc-shaped rotary plate 6 a made of a steel plate having a thickness of about 1.3 mm. Formed at an equal pitch, a carbide tip blade 7 is fixed to the rotation front side of each blade base 6b, and a small-diameter spacer protrusion 8 protruding downward on the outer periphery of the rotating plate 6a is provided in the circumferential direction. It is formed with 12 equal pitches. The spacer projection 8 is formed by locally denting the flesh portion of the rotating plate 6a located directly inward of each blade 7 so that the blade 7 of the rotating cutter 6 and a protective cover 11 to be described later are formed. The distance from the fixed tooth 12 is held at a specified value.

  The support shaft 10 is inserted through the shaft center portion of the rotating shaft 4, and the upper end portion of the support shaft 10 is non-rotatably connected to the upper wall of the gear case 3 by spline fitting or the like. Projecting downward from the center of the rotary shaft 4 and the upper mounting flange 4a, and a protective cover 11 having a diameter of about 230 mm is integrally connected to the projecting portion via the lower mounting flange 10a. Reference numeral 10b denotes a fixing screw for fixing the protective cover 11 to the lower mounting flange 10a. The protective cover 11 is formed of a steel plate having a thickness of about 1.3 mm. As shown in FIGS. 2 and 3, the protective cover 11 is formed with fixed teeth 12 on the outer peripheral portion of the disk-shaped substrate 11a. The grounding protrusions 13 projecting downward are formed at equal pitches in the circumferential direction on the outer peripheral portion of the substrate 11a positioned on the inner peripheral side.

  The fixed teeth 12 are formed on the front part (left part in FIG. 2) and the left and right parts (upper and lower parts in FIG. 2) of the substrate, and the pitch of each fixed tooth 12 is about 3 minutes of the pitch of the blades 7 of the rotary cutter 6. 1 and the blade height of the fixed tooth 12 is made substantially the same as the blade height of the blade 7 of the rotary cutter 6. The fixed teeth 12 positioned on the front side of the substrate 11a are serrated fixed teeth 12a, and the fixed teeth 12 positioned on the left and right of the substrate 11a are corrugated fixed teeth 12b.

  As shown in FIGS. 1 and 2, the grounding protrusion 13 is curved in a spherical shape with the outer peripheral portion of the substrate 11a facing downward, and has a diameter of 30 mm to 35 mm, which is below the lower surface of the substrate 11a. The amount of protrusion is set to 5 mm to 8 mm. The ground protrusion 13 may be formed of a metal plate or plastic separate from the substrate 11a.

  A driven bevel gear 15 fixed to the rotary shaft 4 and a drive bevel gear 16 meshing with the driven bevel gear 15 are rotatably supported in the gear case 3 described above. The drive bevel gear 16 is connected to an end portion of a drive shaft 17 inserted into the rod 1, and the drive shaft 17 is connected to a motor (engine) attached to the upper portion of the rod 1 and is rotated by the motor. In addition, the dimension and the number of blades of each part of the rotary cutter 6 and the protective cover 11 described above are set as appropriate depending on the type of harvested material, the rotational speed of the rotary cutter, or the like.

  According to the above-described embodiment, when the scissors 1 are operated and the cutter head 2, and thus the protective cover 11, is moved along the ground G in a substantially horizontal position, the advancing side fixed teeth 12 grow on the ground G. The weeds are captured and cut with the blade 7 of the rotary cutter 6. At this time, when the protective cover 11 is too close to the ground G, the grounding protrusion 13 provided on the protective cover 11 comes into contact with the ground G and lifts the fixed teeth 12 from the ground G. It stops touching. If the protective cover 11 is too close to the ground G in the inclined state, the forward-side grounding protrusion 13 facing downward comes into contact with the ground G, and the stationary-side fixed teeth 12 are lifted from the ground G. Contact and biting of the fixed tooth 12 with the ground G are prevented.

  For this reason, the operator can perform the brushing operation without being distracted by the inclination angle of the cutter head 2 (protective cover 11) with respect to the ground G, and even the unskilled worker can easily perform the brushing operation. Will be able to. In addition, since the spacer projection 8 is provided on the outer peripheral portion of the rotary cutter 6, even if a large load or impact is applied to the outer peripheral portion of the rotary cutter 6 and the protective cover 11 during the cutting operation, the spacer projection 8 becomes the blade of the rotary cutter 6. 7 and the fixed tooth 12 of the protective cover 11 are reliably held at a specified value, and damage due to collision of both blades is prevented, and the cutting performance is stabilized.

It is a cross-sectional side view of the cutter head part of the brush cutter which shows the Example of this invention. It is a top view of a protective cover. FIG. 3 is a sectional view taken along line III-III in FIG. 2. It is a top view of a rotary cutter. It is VV sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brush cutter 2 Cutter head 3 Gear case 4 Rotating shaft 4a Upper mounting flange 4b Fixing screw 5 Bearing 6 Rotating cutter 6a Rotating plate 6b Blade base 7 Blade (chip)
8 Spacer projection 10 Support shaft 10a Lower mounting flange 10b Fixing screw 11 Protective cover 11a Substrate 12 Fixed tooth 13 Ground projection 15 Driven bevel gear 16 Drive bevel gear 17 Drive shaft G Ground

Claims (3)

  A rotary cutter (6) having a large number of blades (7) on the outer peripheral portion is provided at the tip of the cage (1) equipped with a motor, and a non-rotating protective cover (11) is provided on the lower surface side of the rotary cutter (6). ) And a fixed tooth (12) facing the blade (7) of the rotary cutter (6) on the outer periphery of the protective cover (11). A brush cutter having an outer peripheral portion and a grounding projection (13) projecting downwardly with a gentle inclination on the axis side of the fixed tooth (12).   2. The brush cutter according to claim 1, wherein the grounding protrusion (13) is formed by locally bending the substrate (11a) of the protective cover (11) downward.   Spacer protrusions (on the outer periphery of the rotary cutter (6) or the protective cover (11)) that keep the distance between the blade (7) of the rotary cutter (6) and the fixed tooth (12) of the protective cover (11) at a specified value. The brush cutter according to claim 1 or 2, wherein 8) is provided at a predetermined pitch in the circumferential direction.

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