JPH0534506Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a cutting blade device for a brush cutter used for mowing grass, etc., and specifically relates to a cutting blade device with an extended usable period.

[Conventional technology]

FIG. 5 shows a conventional cutter blade type cutting blade 10 (eg, Japanese Utility Model Application Publication No. 100845/1983). The four convex portions 12 are arranged on the cutting blade 1 so as to protrude outward in the radial direction.
The blade portions 14 are formed at 90° intervals in the rotation direction of
They are formed on both side edges of each convex portion 12. Insertion hole 1
6 is formed at the center of the cutting blade 10, and the drive shaft is inserted therethrough. Regarding the rotational direction of the cutting blade 10, each convex portion 1
The blade 14 on the side edge of the front end of the blade cuts grass, etc., and if the blade 14 becomes less sharp, it will be turned upside down.
The blade part 14 on the front end side in the rotation direction is changed, and the blade part 1
4 cuts the object to be cut, thereby cutting the blade part 1
4 can be used for twice as long as the cutting blade 10 which is formed only on one side edge of the convex portion 12.

FIG. 6 shows another conventional cutting blade 18 (eg, Japanese Utility Model Application No. 62-53623). This cutting blade 18 is
The sawtooth shape has a total of eight sawtooths 20 that protrude outward in the radial direction and engage the cutting blade 18 at equal intervals in the rotational direction.
It is formed around the periphery of. With respect to the rotational direction of the cutting blade 18, the front end side edge of each sawtooth 20 is connected to the cutting blade 1.
8, and forms a blade portion 22.

[The problem that the idea aims to solve]

Although the cutting blade 10 of FIG. 5 has a usable period twice as long, it is still shorter.

When the cutting blade 18 shown in FIG. 6 deteriorates in sharpness, it is necessary to replace it with a new cutting blade 18, and the usable period is short.

The object of this invention is to provide a cutting blade device for a brush cutter that can extend the usable period of the cutting blade.

[Means to solve the problem]

This invention will be explained using reference numerals in the drawings that correspond to the embodiments.

A cutting blade device 32 of a brush cutter 24 according to a first aspect of the present invention includes a cutting blade 40 that projects outward in the radial direction and is provided with tooth-like protrusions 46 having blade portions 48 formed on the side edges thereof at appropriate intervals in the rotational direction; The cutting blade 40 can be rotated integrally with the cutting blade 40 so that its relative position with respect to the cutting blade 40 can be freely adjusted. 48
The cover 50 has a notch 58 that selectively exposes the cover 50.

In the cutting blade device 32 of the brush cutter 24 according to the second aspect, the tooth-like protrusions 46 are formed at equal pitches in the rotational direction of the cutting blade 40, and the length of the notch 58 in the rotation direction is equal to the tooth-like protrusion. The pitch of the portion 46 is approximately equal to the pitch of the portion 46.

In the cutting blade device 32 of the brush cutter 24 according to the third aspect, the blade portions 48 are further formed on both side edges of the tooth-like protruding portion 46, and the contact surface of the cutting blade 40 can be reversed with respect to the cover 50. .

[Effect]

In the invention of claim 1, the cutting blade 40 and the cover 50 are fixed to each other at a predetermined relative rotational position and rotate integrally. Of the blade portions 48 on the side edges of the tooth-like protrusions 46 of the cutting blade 40, only the blade portions 48 located in the cutout portions 58 of the cover 50 can collide with the object to be cut and cut it. The other blade part 48 is the cover 5
It is covered with a covering portion 59 of 0, so that it does not collide with or cut the object to be cut, and is therefore in an unused state.

When the cutting edge of the blade portion 48 exposed at the notch portion 58 deteriorates, the relative rotational position between the cutting blade 40 and the cover 50 is shifted, and as a result, another blade portion 4
8 is located in the notch 58 to cut the object to be cut.

In the cutting blade device 32 according to the second aspect, only one blade portion 48 is located in one notch portion 58 .

In the cutting blade device 32 of the third aspect, by reversing the cutting blade 40, the blade portion 48 on the other side edge of each tooth-like protrusion 46 becomes the front end side in the rotational direction of the cutting blade 40, By being located in the notch 58 of the cover 50, the object to be cut can be cut.

〔Example〕

This invention will be explained below with reference to the embodiments shown in FIGS. 1 to 4.

FIG. 4 is a perspective view of the brush cutter 24. Brush cutter 2
4 has a support pipe 26 extending long in the center,
A power section 28 with an engine is coupled to the upper end side of the support pipe 26. The gear case 30 is connected to the lower end side of the support pipe 26, and the cutting blade device 32 is disposed below the gear case 30 and rotates from the engine-equipped power section 28 via a transmission shaft in the support pipe 26 and a gear in the gear case 30. It is rotated by a drive shaft (not shown) on the lower surface side of the gear case 30 to which power is transmitted. The handle 34 is fixed to the support pipe 26 so as to protrude left and right, and a throttle lever 36 and a start switch 38 are attached to the tip of the handle 34 and control the throttle opening and the engine throttle opening of the engine-equipped power section 28, respectively. Controls the starter starter motor drive.

FIG. 1 is a front view of a cutting blade 40, which is one component of the cutting blade device 32 shown in FIG. The cutting blade 40 is formed into a flat plate shape and has an insertion hole 42 in the center.
The locking notch 44 is formed at an angle of 45° along the periphery of the insertion hole 42 . 16 tooth-like protrusions 46
are formed at equal angular intervals along the peripheral edge of the cutting blade 40 so as to protrude outward in the radial direction, and blade portions 48 are formed on both side edges of each tooth-like protrusion 46 .

FIG. 2 shows the cover 50 facing downward, that is, the cutting blade 40
The side view, FIG. 3, is a right side view when FIG. 2 is taken as a front view. The boss portion 52 is connected to the cover 50
It has an insertion hole 54 in the center into which the drive shaft from the gear case 30 is inserted, and can be fitted into the insertion hole 42 of the cutting blade 40 at the outer periphery. The two projecting parts 56 are formed on the outer peripheral surface of the boss part 52 at positions of 180° in the circumferential direction so as to project outward in the radial direction, and are fitted into the locking notches 44 of the cutting blade 40. It is designed to lock in the rotating direction. Four exposure notches 58 are formed at 90° intervals on the periphery of the cover 50, and a covering portion 59 covering the side edge of the blade portion 48 is formed between these notches 58. In FIG. 2, the length in the rotational direction is equal to the pitch of the tooth-like projections 46 of the cutting blade 40.

The operation of the embodiment will be explained.

The cover 50 is rotated from one end surface side of the cutting blade 40 such that the relative rotational position with respect to the cutting blade 40 is selected so that the pair of overhanging parts 56 fit into the predetermined locking notches 44 of the cutting blade 40. , the boss portion 52 is connected to the cutting blade 4
0 into the insertion hole 42. Thereby, the cutting blade 40 and the cover 50 are fixed at a predetermined relative rotational position and rotate integrally. Regarding the rotation direction, the length of the notch 58 of the cover 50 is the same as that of the cutting blade 40.
Since the pitch is equal to the pitch of the tooth-like protrusion 46 of
tooth-like protrusions 46 are located. cover 50 no 4
Only the four blade parts 48 in total located in the four exposure notches 58 can collide with the object to be cut and cut it. The other blade portions 48 are covered by the periphery of the cover 50, do not collide with or cut the object to be cut, and are therefore not in use.

When the cutting edge of the blade portion 48 exposed at the notch portion 58 deteriorates, the engagement of the cutting blade 40 that fits into the overhang portion 56 of the cover 50 is reduced so that the relative rotational position between the cutting blade 40 and the cover 50 is shifted by 45°. The locking notch 44 is changed to the next locking notch 44. As a result, the new blade part 48 is located in the notch part 58 and cuts the object to be cut. Cutting blade 40 and cover 50
The relative rotational position can be changed a total of four times on one side of the cutting blade 40.

After using the blade portion 48 on the front side edge of the toothed protrusion 46 in one direction of rotation, next, the cutting blade 40 is turned over and the side surface of the cutting blade 40 on the cover 50 side is changed. As a result, until now, the blade portion 48 that was on the side edge of the tooth-like protrusion 46 on the rear end side in the rotational direction
located at the side edge of the tooth-like protrusion 46 on the front side in the rotational direction,
It is used in the same way as the blade part 48 that was on the front end side before the change.

In this way, the cutting blade 40 can be used a total of eight times by changing the relative rotational position with respect to the cover 50 and changing the side surface on the cover 50 side.

[Effect of idea]

According to the invention of claim 1, by shifting the relative rotational position of the cutting blade and the cover, it is possible to sequentially change the blade part that is located in the notch part of the cover and is capable of cutting the object to be cut. Become. In this way, as the cutting edge of the blade deteriorates, by changing the blade located in the notch, the usable period of one cutting blade can be significantly extended.

In the invention of claim 2, by positioning one blade in one notch of the cover, the cutting blade is cut as many times as the number of tooth-like protrusions of the cutting blade divided by the number of notches. can be used, increasing the number of uses to the maximum.

In the invention of claim 3, furthermore, by inverting the cutting blade and using it, it is possible to use the blade part at the side edge on the other side of the tooth-shaped projection, and the entire usable period of the cutting blade can be reduced. further increases.

[Brief explanation of the drawing]

Figures 1 to 4 relate to an embodiment of this invention, in which Figure 1 is a front view of a cutting blade which is a component of the cutting blade device shown in Figure 4, and Figure 2 is a view with the cover facing downward, that is, on the cutting blade side. Figure 3 is a right side view of Figure 2 as a front view, Figure 4 is a perspective view of the brush cutter,
5 and 6 relate to the prior art, FIG. 5 is a diagram showing a cutter blade type cutting blade, and FIG. 6 is a diagram showing another conventional cutting blade. 24...brush cutter, 32...mower blade device, 40...
Cutting blade, 46... Tooth-shaped protrusion, 48... Blade portion, 50
... Cover, 58 ... Notch portion, 59 ... Covering portion.

Claims (1)

[Claims for Utility Model Registration] (1) A cutting blade 40 that projects outward in the radial direction and is provided with tooth-shaped protrusions 46 formed with blade portions 48 on the side edges at appropriate intervals in the rotational direction, and this cutting blade. The blade portion 48 is alternately selected with a covering portion 59 that can be mounted integrally with the cutting blade 40 so as to freely adjust its relative position in the rotational direction with respect to the cutting blade 40 and covering the side edge of the blade portion 48. A mower blade device for a brush cutter, comprising a cover 50 having a cutout portion 58 that is exposed to the outside. (2) The tooth-like projections 46 are formed at equal pitches in the rotation direction of the cutting blade 40, and the length of the notch 58 in the rotation direction is approximately equal to the pitch of the tooth-like projections 46. 1. The brush cutter blade device according to 1. (3) The blade portion 48 is formed on both side edges of the tooth-shaped protrusion 46, and the cutting blade 40 is capable of reversing its contact surface with respect to the cover 50.
The brush cutter blade device described.