JPH08149915A - Cord cutter type brush cutter - Google Patents

Abstract

(57) [Abstract] [Purpose] The engaging and fixing parts of the upper and lower body cases of the cutting blade device of the cord cutter type brush cutter are easy to attach and detach, and
Provided is a cord cutter type brush cutter that does not generate vibration in the upper and lower body case portions during mowing work. [Configuration] Two upper and lower body cases 20 and 21 having a cutting blade cord 33 stored therein are engaged and fixed. Equipped with the cutting blade device 13 and the inner cylindrical portion 27 of the lower body case 21 is fitted to the stem 26 of the upper body case 20.
6, the rotary drive shaft 23 is fixed to the fixing member 2 via an annular holding member 30 which is in circumferential contact with or close to the inner circumference of the inner cylindrical portion 27.
5 is characterized by a cord cutter type brush cutter 10, and more specifically, the annular holding member 30 is a tightening washer, a tightening washer and an O-ring arranged on the outer periphery thereof, and
Be composed of a cylindrical washer, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cord cutter, and in particular to
The present invention relates to a support structure for a main body case portion of a cutting blade device of a cord cutter type brush cutter using a nylon cord or the like as a cutting blade.

[0002]

2. Description of the Related Art As shown in FIG. 1, a general cord cutter type brush cutter 10 is provided with a prime mover 12 such as an air-cooled two-cycle gasoline engine at one end of an operating rod 11 and a cutting blade device 1 at the other end.
3 is arranged and a handle 14 is fixed to an intermediate portion thereof, and a plurality of cords 3 are arranged at equal intervals from the outer circumference of the cylindrical body case 20, 21 of the cutting blade device 13.
3, 33 extend in the radial direction.

The power of the prime mover 12 is transmitted via a drive shaft (not shown) arranged in the operating rod 11 and a bevel gear (not shown) in a gear case 40 arranged above the cutting blade device 13. It is adapted to be transmitted to a cord driving portion of the cutting blade device 13, and the cords 33, 33 are rotated by the driving, thereby performing a grass cutting operation.

Then, the conventional cord cutter type brush cutter 10 is used.
The cutting blade device 13 has, for example, a configuration as shown in FIG. In this structure, the upper main body case 20 and the lower main body case 21 are fitted and fixed, and the upper and lower main body cases 2 are
A cord reel 22 having a cutting blade cord 33 wound therein is sandwiched and held in the internal spaces 0 and 21 from above and below.
The upper main body case 20 is fixed by screwing a nut 25 to a screw portion 23a at the tip of a rotary drive shaft 23 driven by the prime mover 12 via a flat washer-like tightening fitting 24. The upper main body case 20 and the lower main body case 21 are engaged and fixed by holding the claws (not shown) at two locations on the outer peripheral portion and fitting and coupling at the inner center. The fitting and coupling are performed by fitting the inner tubular portion 27 of the lower body case 21 to the stem 26 of the upper body case 20, and thereby,
It has a function of holding both the main body cases 20 and 21.

[0005]

As described above, since the upper and lower body cases 20 and 21 of the cutting blade device 13 of the conventional cord cutter type brush cutter 10 can be easily attached and detached,
For maintenance of cutting blade cord replenishment, welding of cutting blade cords in the upper and lower body cases 20 and 21, and maintenance of the upper and lower body cases 20 and 21 due to cutting at the cutting blade cord take-out through hole 28. Is effective, but the locking claws on the peripheral part of the upper body case 20 are locked in the claw locking holes on the peripheral part of the lower body case 21 to engage the upper and lower body cases 20, 21. In order to fix it, the locking part needs some play. Therefore, the stem 26 at the inner center of the upper and lower body cases 20 and 21 is formed.
There is also some play between the inner cylindrical portion 27 and the inner cylindrical portion 27 so that the upper and lower body cases 20 and 21 can be smoothly attached and detached.

However, the upper and lower body cases 2
There is a problem that the play at the engaging and fixing portions of 0 and 21 becomes one of the causes of vibration of the cord cutter type brush cutter 10 during the brush cutting work using the cord cutter type brush cutter 10. there were. Further, since the stem 26 of the upper main body case 20 has the nut 25 arranged at the lower end thereof and is integrally fixed to the rotary drive shaft 23, when the stem 26 is engaged and fixed to the lower main body case 21, The stem 26
A space for arranging nuts etc. is required at the bottom of the
If the stem 26 is too long in the axial direction, it becomes difficult to perform the integral molding process, and when the stem 26 is fitted to the lower main body case 21, a problem such as difficulty in fitting occurs.

The present invention has been made in view of the problem of the upper and lower body case engaging and fixing structure of the cutting blade device in such a conventional cord cutter type brush cutter. (EN) Provided is a cord cutter type lawn mower in which engaging and fixing portions of upper and lower body cases can be easily attached and detached, and vibration does not occur in the upper and lower body case portions during a lawn mowing operation.

[0008]

In order to achieve the above-mentioned object, a cord cutter type brush cutter according to the present invention is a cutting blade device in which two upper and lower body cases having cutting blade cords housed therein are engaged and fixed. The inner cylindrical portion of the lower main body case is fitted to the stem of the upper main body case, and the rotation drive shaft is attached to the stem through an annular holding member which is in circumferential contact with or close to the inner circumference of the inner cylindrical portion. And more specifically, the annular holding member is a tightening washer, a tightening washer and an O-ring arranged around the tightening washer, and
It is characterized by being composed of a cylindrical washer or the like.

[0009]

[Operation] In the cord cutter type brush cutter according to the present invention configured as described above, in assembling the cutting blade device, the rotary drive shaft is passed through the through hole of the stem of the upper main body case and the annular holding member is interposed. To fix the fixing member (nut) to the screw portion of the rotary drive shaft by screwing. Then, the cord reel is housed inside, and the lower body case is engaged and fixed to the upper body case. The upper body case and the lower body case are engaged and fixed by, for example, holding the claws at two locations on the outer peripheral portion and fitting the inner tubular portion of the lower body case to the stem of the upper body case at the inner center. It is done by combining. In this engaged and fixed state, the outer peripheral portion of the annular holding member makes circumferential contact with or comes close to the inner periphery of the inner tubular portion, and the occurrence of vibration can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As described above, FIG. 1 is a perspective view showing the overall concept of the cord cutter type brush cutter. FIG. 2 is an exploded perspective view of a cutting blade device of a cord cutter type brush cutter according to an embodiment of the present invention,
FIG. 3 is a vertical cross-sectional view of the cutting blade device, and FIG. 4 is a plan view of the cutting blade device (a view of arrow IV in FIG. 3). 2 to 7 for explaining the embodiment of the present invention, and the same members as those in FIG. 10 of the above-mentioned prior art, are designated by the same reference numerals, and redundant description will be given. Those that are omitted are omitted.

The cutting blade device 13 of the illustrated example has an upper main body case 20 and a lower main body case 21, and the upper and lower main body cases 20 and 21 are made of a material such as a synthetic resin and have an upper surface inside. A cord reel 22 that is detachable from the shift slide ring 32 on the side, a compression coil spring 31, and a nylon cord 33 wound around the cord reel 22 are stored. The upper body case 20 is provided with a stem 26 having a through hole 26a formed in the center thereof and through which the rotary drive shaft 23 protruding from the gear case 40 passes, and a disc-shaped lid portion 34 extending in the circumferential direction and the disc-shaped lid. A short cylindrical portion 34a extending from the outer peripheral end of the portion 34 in the axial direction of the rotary drive shaft 23 is provided. The short tubular portion 34
A pair of locking pawls 35, 35 extending downward along the axial direction are integrally provided at opposite sides of the outer peripheral end of the disk-shaped lid portion 34 at a position somewhat axially from a. .

The lower body case 21 has an inner cylindrical portion 27 extending axially upward in the central portion thereof, and the inner cylindrical portion 27 is loosely fitted to the stem 26 of the upper body case 20. The lower body case 21 includes a disc-shaped bottom portion 36 and a cylindrical portion 36a extending from the outer peripheral end of the disc-shaped bottom portion 36 upward in the axial direction of the rotary drive shaft 23. An inner tubular portion 36b is provided concentrically in the axial direction somewhat from the tubular portion 36a. Also,
Code guides 37 each having a through hole 28 are fitted in two diametrically opposed positions around the cylindrical portion 36a, and each of the code guides 37 extends from the cord reel 22 inside. A nylon monofilament cutting blade cord 33 is guided and extended to an appropriate length outside. Further, claw locking holes 38, 38 for locking and holding the locking claws 35, 35 of the upper body case 20 are formed in the lower facing position of the lower body case 21 (see FIG. 2). .

The upper and lower body cases 20 and 21 are locked with the locking claws 35 and the claw locking holes 38 by inserting the two locking claws 35 into the lower main body case 21. Using the elasticity of the locking claws 35, the locking projections 35a of the locking claws 35 are used for the claw locking holes 3 of the lower body case 21.
It is locked by forcibly fitting from the inside of 8, 8 toward the outside. The upper and lower body cases 20,
The cord reel 22 arranged in the reference numeral 21 is provided with a tubular shaft portion 22c and a pair of upper and lower flange portions 22a and 22b extending in a radial direction from the tubular shaft portion 22c.
Nylon cord 33 is caught between 2b.
An inner flange portion 22d is provided inward of the tubular shaft portion 22c, and the inner tubular portion 27 of the lower body case 21 is provided.
Extends to a position where it contacts the outer peripheral surface of the.

The inner flange portion 22 of the cord reel 22.
The shift slide ring 32 is rotatably fitted to the outer periphery of the inner tubular portion 27 at the upper part of d, and the lower surface of the shift slide ring 32 and the cord reel 2 are attached.
2, the coil spring 31 is interposed between the upper surface of the inner flange portion 22d and the shift slide ring 3
2 is biased upward. Further, a plurality of shallow irregularities (not shown) are provided on the upper surface of the shift slide ring 32 at equal intervals in the circumferential direction to engage with the irregularities (not shown) provided on the lower surface of the upper body case 20. However, the cord reel 22 is normally prevented from rotating.

The rotary drive shaft 23 driven by the prime mover 12 has a bevel gear (not shown) fixed to an upper end thereof in the gear case 40 and a screw portion 23a at a lower end thereof. A regular hexagonal block body 23b is integrally provided in the middle portion. To fix the upper main body case 20 and the rotary drive shaft 23, the rotary drive shaft 23 is inserted into the through hole 26a of the stem 26 of the upper main body case 20.
3, the regular hexagonal block body 23b is fitted into the regular hexagonal recess 34b provided on the upper surface of the upper body case 20, and the nut 25 is screwed and fixed to the screw portion 23a via the annular holding member 30. To do.

The annular holding member 30 has a cylindrical shape in the embodiment shown in FIGS. 2 and 3, and the rotary drive shaft 23
It has a shaft hole 30e that fits in and has an O-ring 30a fitted on the outer periphery. The outer peripheral surface of the O-ring 30a is arranged so as to be pressed into contact with the inner peripheral surface of the inner cylindrical portion 27 of the lower main body case 21 with appropriate tightness. In the cord cutter type brush cutter 10 according to the embodiment of the present invention having such a configuration, an operator suspends the operation rod 11 from a shoulder via a belt (not shown) and handles 1
4 is to be grasped by hand, and the cutting blade device 13 performs the mowing work. The power transmission to the cutting blade device 13 drives the prime mover 12 to drive the drive shaft in the operating rod 11 ( The rotation drive shaft 23 is rotated via a bevel gear (not shown) in the gear case 40 (not shown). The axis 2
When 3 rotates, the upper and lower body cases 20 and 21 including the cord reel 22 rotate together, so that the nylon cord 33 extending and exposed from the outer peripheral portion of the lower body case 21 is also integrated. It rotates to the left and becomes rigid due to the action of centrifugal force to mow grass and the like.

The upper and lower body cases 20 and 21
In the central portion thereof, the stem 26 and the inner tubular portion 27 are loosely fitted, but the intermediate portion of the inner tubular portion 27 is held in contact by the O-ring 30b of the annular holding member 30. Therefore, the upper and lower body cases 20 and 21 and the like are in vibration-proof engagement with each other. Further, when it is necessary to pay out the nylon cord 33 because the exposed portion of the nylon cord 33 is shortened or the like, when the shock is given by hitting the cutting blade device 13 on the ground, the shift is caused. The slide ring 32 temporarily moves downward against the urging force of the coil spring 31 and disengages from the upper main body case 20, so that the cord reel 22 rotates by a predetermined angle and the nylon cord 33.
Can be fed out by a predetermined size.

Further, when the upper and lower body cases 20 and 21 are disengaged from each other in order to replenish the nylon cords 33 in the upper and lower body cases 20 and 21, and the upper and lower body cases 20 and 21 are separated, The locking claw 3 of the main body case 20
This is done by pressing the projection end 35a of No. 5 inward against the elastic force of the locking claw 35, and thereby releasing it inwardly from the locking hole 38.

FIG. 5 shows another embodiment of the present invention, in which a tightening washer 30b having an outer diameter dimension slightly larger than the inner diameter of the inner cylindrical portion 27 is used as an annular holding member. is there. In this embodiment, since the tightening washer 30b is almost fixed to the intermediate portion of the inner cylindrical portion 27, the upper and lower body cases 20 and 21 are more firmly fixed and engaged, and vibration is prevented. Suppress the occurrence of.

FIG. 6 shows still another embodiment, in which a cylindrical washer 30c having an outer diameter dimension close to the inner diameter of the inner cylindrical portion 27 is used as an annular holding member. In this embodiment, the cylindrical washer 30c has the inner cylindrical portion 2
Since it is located to the inner part of 7 and is almost in contact with the inner tubular part 27, the upper and lower body cases 20, 21 are
The engagement and fixation of is made firm and the generation of vibration is suppressed.

FIG. 7 shows still another embodiment, in which a hexagon socket head nut 30d having an outer diameter dimension close to the inner diameter of the inner tubular portion 27 is used as an annular holding member together with a spring washer 39. It is a thing. In this embodiment, the hexagon socket head nut 30d is located to the inner part of the inner tubular portion 27 and almost contacts the inner tubular portion 27, so that the upper and lower body cases 20 and 21 are engaged with each other. and that the engagement securing firm, while suppressing the occurrence of vibration, the hexagonal Anazuke bolt 30d is provided with a hexagonal hole 30d ₁ and screw portion 30d ₂ of the tightening, also serves as a fixed member and the annular holding member It is a thing. 8 and 9 show the tightening washer 30 with the O-ring 30a and the tightening washer 3 among the above-described embodiments.
11 is a graph showing the results of two experimental examples compared with the conventional example of FIG. 10 for the annular holding member of 0b only.

The vertical axis of each graph shows the acceleration of vibration, and the horizontal axis shows each measurement position in the circumferential direction of the shift slide ring (six divisions) for feeding the nylon cord. As can be seen from the graphs, both the tightening washer 30 with the O-ring 30a and the annular holding member having only the tightening washer 30a have a smaller vibration acceleration than the conventional example, and the vibration is reduced. I understand. Although the present invention has been described in detail with respect to some embodiments, the present invention is not limited to the above embodiments, and various modifications can be made in design without departing from the present invention described in the claims. Can be changed.

For example, although the cutter using a nylon cord has been described, it goes without saying that the cord may be a metal cord other than nylon, and the rotary drive source is not limited to the internal combustion engine, but may be an electric motor. Further, the annular holding member is not limited to the above embodiment, and may have any shape as long as it can hold the inner tubular portion from the inside of the tubular portion.

[0024]

As can be understood from the above description, according to the present invention, the vibration of the cutting blade device is effectively suppressed, so that the operator grasps the operation rod and smoothly and stably wipes grass and the like. Therefore, the fatigue of the operator can be reduced, and the work efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a cord cutter type brush cutter according to the present invention.

FIG. 2 is a development view of a cutting blade device according to an embodiment of the present invention.

3 is a vertical cross-sectional view of the cutting blade device of FIG. 2 (viewed in the direction of arrows III-III in FIG. 4).

FIG. 4 is a plan view seen from the direction of arrow IV in FIG.

FIG. 5 is a vertical sectional view of a cutting blade device according to another embodiment of the present invention.

FIG. 6 is a vertical sectional view of a cutting blade device according to still another embodiment of the present invention.

FIG. 7 is a vertical sectional view of a cutting blade device according to still another embodiment of the present invention.

FIG. 8 is a first vibration comparison experimental diagram of an example of the present invention and a conventional example.

FIG. 9 is a second vibration comparison experimental diagram of the example of the present invention and the conventional example.

FIG. 10 is a vertical cross-sectional view of a cutting blade device of a conventional cord cutter type brush cutter.

[Explanation of symbols]

 13 ... Cutting blade device 20 ... Upper body case 21 ... Lower body case 22 ... Cord reel 23 ... Rotation drive shaft 25 ... Nut (fixing member) 26 ... Stem 27 ... Inner tubular portion 30 ... Annular holding member 30a ... O-ring 30b … Tightening washer 30c… Cylindrical washer 30d… Hexagonal columnar nut 33… Cutting blade cord

Claims (5)

[Claims] 1. A cord cutter type brush cutter 10 comprising a cutting blade device 13 having two upper and lower body cases 20 and 21 having a cutting blade cord 33 housed therein, wherein an inner cylindrical portion of the lower body case 21. 27 is the upper body case 20
Of the rotary drive shaft 23.
Is fixed by a fixing member 25 via an annular holding member 30 that is in circumferential contact with or close to the inner circumference of the inner tubular portion 27. 2. The cord cutter type brush cutter according to claim 1, wherein the annular holding member is a tightening washer 30b. 3. The cord cutter type brush cutter according to claim 1, wherein the annular holding member is a tightening washer 30 and an O-ring 30a arranged on the outer periphery thereof. 4. The annular holding member is a cylindrical washer 30c.
The cord cutter type brush cutter according to claim 1, wherein 5. The cord cutter type mower according to claim 1, wherein the annular holding member is a hexagonal columnar nut 30d.