JPH0216586Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an automatic rotation locking device for a brush cutter in which an operating stick can freely rotate relative to the engine side.

[Conventional technology]

Conventionally, the base of the operating rod, which has a cutting blade connected to the tip side, is rotatably fitted and connected to a cylindrical portion of a clutch housing fixed to the engine, and the cylindrical portion is provided with a suspension for a hanging band. Regarding a brush cutter constructed by connecting metal fittings, the applicant filed a patent application in 1983.
As seen in No. 97977, the structure was such that it could be prevented from rotating using a fastener such as a wing nut.

[Problem that the invention attempts to solve]

With this type of brush cutter, when working on slopes, etc., you have to hold the handle to operate it, so the weight of the engine is no longer applied to the suspension band, causing the engine to rotate relative to the control stick or fall over. In addition, when starting or transporting the engine, the engine will rotate or fall over, so you will have to operate the fasteners each time to stop it from rotating, which can be troublesome and reduce work efficiency. It had some problems.

[Means for solving problems]

The present invention solves this problem and automatically prevents rotation.
The bush that is non-rotatably fitted into the cylindrical part of the clutch housing is formed with a clamping piece that can be crimped onto the operating rod using a fastener, and a suspension whose proximal end is pivoted to the upper part of the cylindrical part is formed. A cam part is formed at the lower part of the fitting to engage with the tightening piece and press the tightening piece to the tightening side, and to apply downward pressure to the tip side of the hanging fitting which moves upward during hanging. It was constructed with a lot of effort.

[Effect]

Therefore, if the tightening piece of the bushing is crimped onto the operating stick using a tightening tool, the operating stick can be locked against the engine side and prevented from rotating, and the state in which it is not tightened by the tightening tool can be prevented. However, if the engine is not suspended by the suspension band, the cam part of the suspension fitting that is pressed downward will push the tightening piece toward the tightening side, and the tightening piece will automatically tighten the operating rod. This means that the rotation can be stopped.

〔Example〕

Next, the embodiment shown in the drawings will be described.

FIG. 2 shows a partially cutaway side view of a part of the brush cutter. Inside the clutch housing 2, which is integrally fixed to the engine, a boss 7a of a centrifugal clutch drum 7 is mounted on a shaft via a bearing 8. However, a long operating rod 1 is located inside the cylindrical portion 2a of the clutch housing 2.
The base of the power transmission shaft 10 is fitted in a rotatable manner and locked in the axial direction by a snap spring 9, and the end of the transmission shaft 10 fitted into the operating stick 1 is spline-fitted 11 into the boss 7a. The handle is fixed and the cutting blade is pivoted below the gear case connected to the tip side, making it similar to the conventional structure.

A U-shaped protrusion 12 is integrally formed above the tip of the cylindrical portion 2a of the clutch housing 2, and protrusion walls 13a and 13b on both sides of an opening formed at the rear of the protrusion 12 are provided with a U-shaped protrusion 12. has a hexagonal recess and a round hole 14a on one side, and a large diameter hole 1 on the other side.
4b respectively, and a slit 12a is formed on the upper surface of the protruding part 12 rearward from the said part, and the protruding part 1 is formed from the front end above the center of the protruding part 12.
2, an upright wall 15 is provided upright at the rear end of the upright wall 15, a horizontal recessed hole 16 is formed at the rear end of the upright wall 15, and a cutout surface 17 is formed below the outer end surface of the recessed hole 16. do.

4 is a bush in which the operating rod 1 is rotatably fitted and can be fitted inside the cylindrical portion 2a, and on the upper side of the distal end thereof is fitted into the protruding portion 12. A protruding portion 4c that can be locked in the rotational direction is integrally formed, and two arc-shaped clamping pieces 4a and 4b that can be pressed against the operating rod 1 are upwardly provided from both sides that are intermediate in the front-rear direction. A horizontal hole 18 is provided at the upper end of both fastening pieces 4a and 4b.
a and 18b are formed in correspondence with each other, and a cut surface-shaped cam portion 19 is provided at the upper end of one of the tightening pieces 4a.
The head of the bolt 5a is fitted into the hole 14a, and the bolt 5a is inserted into the horizontal holes 18a, 18b and the hole 14b, and a collar 20 is fitted onto the tip side of the bolt 5a. A wing nut 5b is screwed onto the tip of the bolt 5a so as to contact the tip of the collar 20, and the bolt 5a and the wing nut 5b are screwed together.
Both the clamping pieces 4a and 4b are mounted on the operating rod 1 by a clamping tool 5 such that they can be tightened or loosened.

Reference numeral 3 denotes a hanging metal fitting, which has holes 3a on its tip side for connecting hanging bands, and a bolt 22 to be fitted with a seat plate 21 interposed on the base end side of the hanging metal fitting 3 is inserted into the recessed hole 1.
6, one end of the torque spring 23 housed in the recessed hole 16 is locked to the inner bottom surface of the recessed hole 16, and the other end is exposed to the cutout surface 17. The torque spring 23 presses the distal end side of the hanging fitting 3 downward, and the lower part of the hanging fitting 3 above the upper end cam part 19 of the tightening piece 4a is fixed to the lower part of the hanging fitting 3. A cut surface-shaped cam portion 6 that extends into the slit 12a is formed.

Therefore, during work, the wing nut 5b is rotated to loosen the fastener 5, and the fastening pieces 4a, 4b are loosened so as not to come into pressure contact with the operating rod 1, and the hanging band connected to the hanging metal fitting 3 is loosened. Work is carried out while carrying the engine over the shoulder and operating it with the handle.However, when the engine is suspended by the suspension band, the weight of the engine is mainly applied, and as shown in Fig. 10, the lower part of one end of the suspension fitting 3 is Torque spring 23 until it hits the top surface of cylindrical portion 2a
, and the hanging fitting 3 rotates upward around the bolt 22 until the cam part 6 is separated above the cam part 19.
can be rotated freely and work can be done in the same way as the conventional type.

In this state, when the weight of the engine is no longer on the suspension band when working on a slope, etc., or when starting or transporting the engine, the suspension fitting 3 can be loosened. Then, the hanging fitting 3 is pressed downward by the elastic pressure of the torque spring 23, and as shown in FIGS.
9, the tightening piece 4a is pressed onto the operating rod 1, and the operating rod 1 is then locked against the clutch housing 2 on the engine side and automatically prevented from rotating.

In addition, when suspended by the hanging band, the hanging fitting 3 will rotate upward and the rotation lock will be automatically released as described above, but no matter what condition the hanging fitting 3 is in, By operating 5, rotation can be prevented.

[Effect of idea]

In this way, in the present invention, when the weight of the engine is no longer applied to the suspension band, the cam portion 6 of the suspension fitting 3 engages with the clamping piece 4a and presses the clamping piece 4a against the operating rod 1. As a result, it is possible to automatically prevent rotation without having to operate the fastener 5 each time, and it is also possible to prevent rotation by locking with the fastener 5 as necessary. This eliminates the possibility of the engine tilting or falling when the weight of the brush cutter stops acting on the hanging bracket, when starting the engine, or during transportation, making the brush cutter easier to operate and work with. It has the advantage of having a simple structure and being able to be suitably implemented.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of the main part of an embodiment of the present invention, Fig. 2 is a side view of a partially cut away part of the brush cutter, and Figs. 3 and 4 are taken along the - line in Fig. 2. The cross-sectional views taken along the and - lines are shown, respectively, and the fifth
The figures show a part of Fig. 3, Fig. 6 is a side view of a part of the cylinder, Fig. 7 is a left side view of Fig. 6, Fig. 8 is a side view of the bushing, and Fig. 9 is a side view of a part of the cylinder. 8 is a left side view, and FIG. 10 is an explanatory view of the operation of FIG. 1. 1...Operation stick, 2...Clutch housing, 2
a...Cylinder part, 3...Hanging fitting, 4...Button, 5
... Fastener, 4a, 4b... Tightening piece, 6... Cam part.

Claims (1)

[Scope of utility model registration request] A cylindrical portion 2 of a clutch housing 2 has a base portion of an operating rod 1, which has a cutting blade connected to the tip thereof, fixed to the engine.
In a brush cutter configured by rotatably fitting and connecting to the cylindrical portion 2a and connecting a hanging fitting 3 for a hanging band to the cylindrical portion 2a, the cylindrical portion 2a is unrotatably fitted to the cylindrical portion 2a. The bush 4 includes a clamping piece 4a that can be crimped onto the operating rod 1 by a clamping tool 5;
4b, the lower part of the hanging fitting 3 having its proximal end pivotally connected to the upper part of the cylindrical part 2a includes a cam part that engages with the tightening piece 4a and presses the tightening piece 4a toward the tightening side. 6, and the distal end side of the hanging metal fitting 3, which moves upward during hanging, is elastically biased downward.