JPS584410Y2 - brush cutter - Google Patents

Description

[Detailed description of the invention] This invention is an improvement of a type of brush cutter in which the power transmission shaft that transmits the power of the prime mover to the cutting blade drive unit is connected to the prime mover side and the cutting blade drive unit side by a non-rotating insertion connection. The purpose of this invention is to provide a brush cutter having a structure that can extend the life of the power transmission shaft.

As is well known, in brush cutters, the vibrations of the prime mover are prevented from coming into contact with the human body by interposing a cushioning material made of rubber or the like between the clutch housing attached to the prime mover side and the handle rod connected to the clutch housing. This protects the worker's body by preventing direct contact with the handle rod, but on the other hand, by providing a cushioning material, the handle rod, which should be horizontally fixed to the clutch housing, is protected from the connection part with the clutch housing. Since the mower is mounted in a state where it is bent under its own weight with the base point at the mower, the power transmission shaft, which is installed inside the handle and transmits the power of the prime mover to the mower blade drive section, is connected in a flexed state.

As a result, a combined force of torsion moment (torque) and bending moment acts on the motor-side connecting part of the power transmission shaft, and this combined force causes wear and tear on the spline teeth used as the rotation-preventing insertion part. Damage is the cause of a significant reduction in the life of the power transmission shaft.

Therefore, even if the power transmission shaft is bent due to bending of the temporary handle rod and a bending moment is generated, this invention prevents this bending moment from acting on the rotation prevention insertion part on the prime mover side. The purpose of the present invention is to provide a brush cutter that protects the spline teeth and the like from wear and damage, thereby extending the life of the power transmission shaft.

An embodiment of this invention will be described below based on the drawings.
Reference numeral 1 denotes a power transmission shaft passed through the inside of the handle rod 2, and its tip end is connected by a spline connection to a mower blade drive unit (not shown) provided at the front end of the handle rod 2 in the same manner as is known in the art.

Also, the rear end of the clutch drum 5 is rotatably attached to a clutch housing 3 installed in an engine (not shown) via bearings 4, 4, and a mounting shaft (motor side power transmission shaft connection part) is attached thereto.
6 by a spline connection.

The rear end of the power transmission shaft 1 has a male spline 1a meshed with a female spline (non-rotation insertion hole) 6a formed at the center of the axis of the mounting shaft 6, and a female spline 6a formed at the front of the female spline 6a. Attach the shaft 1 at the rear of the male spline 1a to the pilot part (shaft fitting part) 6b having the same dimensions as the outer diameter.
It is connected to the mounting shaft 6 by fitting the parts.

In addition. In the figure, reference numeral 7 denotes a pin for fixing the position of the power transmission shaft 1, which is fitted onto the mounting shaft 6.

In addition, the rear part of the handle rod 2 is fitted and held in a cushioning material holder 8 attached to the front end of the clutch housing 3, as in the known case, and a mounting tube for the cushioning material 9 is held from the rubber etc. that integrally forms the grip 9a. It is connected to the clutch housing 3 by inserting it into the clutch housing 9b and fixing it with a bolt 10.

As described above, the brush cutter according to this invention has the power transmission shaft connecting portion on the motor side (the mounting shaft of the clutch drum 5 in the embodiment) 6
Detent insertion hole (female spline in the example) 6a
Since the structure has a shaft fitting part (inlay in the embodiment) 6b formed in the front, when the power transmission shaft is connected to the motor side connection part, the power transmission shaft is fitted in front of the locking insertion part. Therefore, even if the power transmission shaft bends due to bending of the handle rod and a bending moment is generated, this bending moment is received by the shaft fitting part and does not act on the rotation-preventing insertion joint. Since only the torsional moment necessary to transmit power acts on the one-turn locking insertion joint, the spline teeth that form the locking insertion portion are protected from wear and damage, thereby extending the life of the power transmission shaft. can be increased.

In addition, in this invention, the anti-rotation insertion part is made of a spline in the embodiment, but this may be combined with a square hole and a square shaft, as long as it does not deviate from the technical idea stated in the claims for utility model registration. Of course, there are various design changes.

[Brief explanation of drawings]

The drawing is a longitudinal sectional view of a main part of an embodiment of this invention. 1...Power transmission shaft, 6...Clutch drum mounting shaft (motor side power transmission shaft connection part), 6a...
...Female spline (non-rotation insertion hole), 6b...
...Inro (shaft fitting part).

Claims (1)

[Scope of utility model registration request] In a type of brush cutter in which the power transmission shaft that transmits the power of the prime mover to the mower blade drive section is connected to the prime mover side and the mower blade drive section respectively by a non-rotating insertion connection, the rotation prevention insertion of the power transmission shaft connection part on the prime mover side is difficult. A brush cutter with a shaft fitting part formed in the front.