JPH025714Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application, target) This invention rotates a cutting blade (circular saw) removably at the tip of a support rod or drive shaft at high speed through a driving engine. The present invention relates to an improvement in a power brush cutter used for cutting down weeds, underbrush, shrubs, etc.

(Prior Art) In conventionally known brush cutters of this type, the engine used to drive the cutting blade (circular saw) is generally non-reversible, so the tip (lower end) of the support rod or drive shaft is Once the brush cutting blade (circular saw) is attached to the specified location, it will only rotate in one direction, either left or right, and if it remains attached, it should not be rotated in the opposite direction (unless it is turned upside down). I can't.

By the way, a circular saw as a cutting blade having 2 to 4 blades, specifically speaking,
The left and right blades (brush cutting blades) of approximately the same shape and size with appropriate width and length are protruded radially from the relatively small circular blade base plate in two, three or four directions (of the circular saw). Along the edges of both sides (front and rear in the direction of rotation), the vanes (blade) are appropriately sharp so that almost the entire length (in the radial direction of the circular saw) can function as a lower (back) blade. When using a cutting blade (circular saw) with a ground edge, take advantage of the special characteristics and advantages of the cutting blade (circular saw).
If you want to use it 100%, you need to use it by flipping both sides (top and bottom). but,
Conventionally, each time the cutting blade (circular saw) was attached or removed, the fixing nut and the cutting blade were removed from the tip of the support rod or drive shaft, and then the cutting blade was turned over and placed in the designated position. The extremely troublesome and cumbersome operation of attaching the bush cutter to the bush cutter and tightening the nut had to be carried out after the main body of the brush cutter had been turned over and placed in a position that would not interfere with the work.

In addition, even if for some reason it is desired to stop the rotation of the cutting blade (circular saw) for a very short period of time while cutting weeds, etc., there is the inconvenience of having to stop the drive engine each time. .

(Purpose and structure of the invention) The present invention was made in view of the above circumstances, and its purpose is to overcome the various inconveniences, inconveniences, and shortcomings as described above found in conventionally known brush cutters of this type. Almost completely resolved and removed,
To provide a brush cutter that is easy to handle and operate and can perform brush cutting work efficiently.

Therefore, the brush cutter according to the present invention uses the brush cutter (circular saw) as part of the power transmission mechanism for driving the brush cutter (circular saw) that is removably attached to the tip of the support rod or drive shaft. A switching device is provided to switch the saw) between forward rotation, reverse rotation, and stop.
b and a right-hand thread 2c are threaded, and the cutting blade (circular saw) 2 is secured to the above-mentioned support by tightening double nuts 8 and 9 that are screwed into these two threaded portions and brought into contact with each other. It is unique in that it can be held and fixed at a predetermined location on the tip of the rod 1 (drive shaft 7).

(Embodiment of the invention) A shoulder-type brush cutter as an embodiment of the invention will be specifically described below with reference to the drawings.

As can be seen in FIG. 1, which is a perspective view schematically showing the entire structure, the tip (lower end) of the long support rod 1 has four blades protruding from a small circular base plate on both left and right sides. A cutting blade (circular saw) 2 consisting of a sharp cutting edge formed along the edge is removably attached via a bolt or nut (not shown), and is provided on the base end side of the support rod 1. The rotational force of the engine 3 is transmitted through a drive shaft (not shown) built into the support rod 1 to rotate the cutting blade (circular saw) at high speed.

This brush cutter is in a state in which the handle 4 attached to the midpoint in the longitudinal direction of the support rod 1 is grasped with both hands, and the lower surface of the brush cutting blade (circular saw) 2, which rotates at high speed, is held almost parallel to the ground and slightly raised. is operated while being held in place. According to the present invention, as part of the power transmission mechanism directly connected to the engine 3, a switching device A is provided for switching the brush cutting blade (circular saw) 2 to forward rotation, reverse rotation, or stop as necessary. There is. FIG. 2 shows an example of the configuration, in which a bevel gear 5a is fixed to a driving shaft 5, which is the output shaft of an engine 3 (not shown), and one end of a driven shaft 6 (left end in the drawing).
mesh with the bevel gear 6a fixed to. On the other hand, on the driven shaft 6, two bevel gears 6b and 6c are loosely mounted facing each other, and a clutch B is attached.

The shaft 7 has one end (base end) fixed to one bevel gear 7a meshed with the opposed bevel gears 6b and 6c, and in order to function as a drive shaft, the other end (tip) is connected to the brush cutting blade. (Circular saw) 2 is connected.

Therefore, when the driving shaft 5 rotates due to the drive of the engine 3, the driven shaft 6 also rotates via the bevel gears 5a and 6a, but as shown in FIG. When in the neutral position, neither of the two bevel gears 6b and 6c rotates, so the rotational force of the engine 3 is not transmitted to the drive shaft 7.

That is, when the clutch B is in this state, the brush cutting blade (circular saw) 2 does not rotate even if the engine 3 is operating.

From the state where clutch B is now seen in Figure 2,
In the figure, for example, by moving to the right, the bevel gear 6c
When the driven shaft 6 is fitted on the side, the rotation of the driven shaft 6 is transmitted to the bevel gear 6c, so the drive shaft 7 rotates clockwise (normally) via the bevel gear 7a that meshes with the bevel gear 6c.
The cutting blade (circular saw) 2 connected to its tip is also rotated clockwise (normally).

Furthermore, in FIG. 2, when the clutch B is moved to the left opposite to the above and fitted into the bevel gear 6b side, the rotation of the driven shaft 6 is transmitted to the bevel gear 6b, so the bevel gear 7a meshing with this is transmitted to the bevel gear 6b. Through the drive shaft 7, in other words, the brush cutting blade (circular saw) 2 is moved in the opposite direction to the above,
In other words, it is rotated to the left (reverse rotation).

In this way, in the brush cutter according to the present invention, the brush cutter (circular saw) 2 can be rotated forward or reverse, that is, rotated in either the left or right direction by operating the switching device A. As is the case with conventionally known brush cutters that can only be rotated in one direction, the cutting blade (circular saw) 2 is screwed in only one direction at the tip of the support rod (drive shaft). If it is installed and fixed by tightening a single nut screwed onto the male threaded part, the screw of the mounting nut will loosen and the attached brush cutting blade (circular saw) may become loose.
There is a danger that it may fall off the tip of the support rod during high-speed rotation and be blown away.

To prevent the cutting blade (circular saw) 2 from loosening or falling off, various methods can be considered such as split nuts, set screws, spring washers, claw washers, loose lock washers, etc. If the mounting shaft 2a of the brush cutting blade (circular saw) 2 is threaded in one direction, and a nut is screwed onto this screw, the direction of rotation of the cutting blade (circular saw) 2 is There is a danger that the screws will loosen due to reverse rotation and the high-speed rotating blade (circular saw) will be blown off, so as shown in Figure 3,
At the tip of the mounting shaft 2a formed at the tip of the support rod 1, a male thread with a left-hand thread 2b and a right-hand thread 2c is provided. It is considered most effective and appropriate to clamp and fix the cutting blade (circular saw) 2 to a predetermined location on the tip of the support rod 1 or the drive shaft 7 by tightening the double nuts 8 and 9 that are in contact with each other. think.

If necessary, a synergistic effect on preventing the cutting blade (circular saw) from loosening and falling off can be expected by using a method such as attaching a split pin 10 to the tip of the mounting shaft 2a as shown in the figure. .

(Effect of the invention) As explained above, in the present invention, the switching device A for switching the cutting blade (circular saw) 2 between forward rotation, reverse rotation, and stop is simply provided as a part of the power transmission mechanism. Not only is there a loosening and falling prevention means that has the most effective and appropriate effect for preventing danger, that is, a left-hand screw 2b and a right-hand screw are attached to the tip of the mounting shaft 2a formed at the tip of the support rod 1. screw 2c
A cutting blade (circular saw) 2 is installed by tightening double nuts 8 and 9 which are screwed into these two threaded parts and brought into contact with each other. Both nuts are provided so as to be clamped and fastened to a predetermined location on the tip of the support rod 1 or the drive shaft 7, so that both nuts prevent each other from rotating as the cutting blade (circular saw) 2 rotates forward or reverse. This prevents the nut from loosening and keeps the engine running smoothly.
You can easily stop the brush cutter by adjusting the brush cutter blade (circular saw) without having to stop the machine each time, so you can move the brush cutter extremely safely during brush cutting work. During actual work, vines, tall grass, etc. may fall on the drive shaft 7.
When the blade is caught in the tip of the mower, it is advantageous in that the tip of the cutting blade 2 and the drive shaft 7 can be reversed without delay in order to prevent it from being further entangled and remove it.

In addition, in conventional brush cutters that are not equipped with a switching device, when the engine 3 is started, for example, the tip of the support rod 1 is turned into a cutting blade due to the instantaneous rotation of the cutting blade 2 itself placed on the ground. It rolls horizontally on the ground at a large size and at a fairly high speed,
Although the extremely dangerous phenomenon of running often occurs, in the brush cutter according to the present invention, the engine 3 can be started by placing the clutch B in the neutral position at the last moment, so that such a situation as described above can be avoided. Its occurrence can be easily prevented.

Furthermore, according to the present invention, the cutting blade (circular saw) is attached to the tip of the support rod 1 or the drive shaft 7.
2 can be freely rotated in either the left or right direction without having to turn the front and back sides of the paper. When using a cutting blade made of blades (circular saw), it is extremely easy to use the left and right cutting blades alternately as the lower blade at any time, so the wear on the cutting blades is equalized and the balance is maintained. In short, by using right-hand and left-hand screws with different tightening directions, you can rotate forward, reverse, stop, and
Even when switching, it is always tightened so that it does not loosen or fall off, so it can be used safely, and its practical effects are extremely great and remarkable.

Although a shoulder-type brush cutter has been described above, the present invention is not limited to the above embodiment, and can be applied to movable brush cutters with wheels and other types and structures of various types and structures. can be applied in the same manner, and in short, it goes without saying that various design changes can be made within the scope of the gist specified in the registered claims.

[Brief explanation of the drawing]

The attached drawings show an embodiment of the brush cutter according to the present invention, in which Fig. 1 is an overall perspective view, Fig. 2 is a plan view showing an example of a switching device, and Fig. 3 shows a fixed state of the cutting blade. FIG. 3 is a partially longitudinal side view. 1... Support rod, 2... Cutting blade, 2a... Mounting shaft,
3... Engine, 4... Handle, 5... Driving shaft, 6... Driven shaft, 7... Drive shaft, 5a, 6a,
6b, 6c, 7a...Bevel gear, 8, 9...Nut, 10...Cotter pin, A...Switching device, B...Clutch.

Claims (1)

[Scope of utility model registration request] Weeds are removed by rotating a cutting blade (circular saw) 2 removably attached to the tip of the support rod 1 (drive shaft 7) at high speed.
In a power-powered brush cutter that cuts undergrowth, shrubs, etc.
As part of the power transmission mechanism for driving the brush cutting blade (circular saw) 2, normal rotation of the brush cutting blade (circular saw) 2;
A switching device A for switching between reverse rotation and stop is provided, and the male threaded portion provided at the tip of the support rod 1 (drive shaft 7) is threaded with a left-hand thread 2b and a right-hand thread 2c. The cutting blade (circular saw) 2 is inserted into a predetermined position at the tip of the support rod 1 (drive shaft 7) through the tightening of double nuts 8 and 9 which are respectively screwed into two threaded parts and brought into contact with each other. A brush cutter characterized by being able to be clamped and fixed to.