JPH0741307Y2 - Rotary blade of brush cutter - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention is to mow grass and the like on the ground by rotating the blade in the horizontal direction by the drive of an engine and using a blade portion provided on the outer periphery. The present invention relates to a rotary blade of a brush cutter such as a brush cutter.

(Prior Art and Problems to be Solved) Conventionally, as shown in FIG. 9, a rotary blade of a brush cutter of this type is provided with a blade portion 91 on the outer circumference of a rotary blade 93 of a single flat disk. Therefore, the rotary blade 93 was rotated at a high speed to mow off grass on the ground with this blade portion 93, but since the rotary blade was flat in its entirety, it was curved with respect to lateral or diagonal loads. It was easy to do, and required a plate thickness greater than the strength required for cutting.

In this configuration, since the rotary blades rotate at high speed, it is dangerous to bounce off small stones, etc., and there is a drawback that soft grass causes cutting residue.Therefore, two rotary blades are overlapped in opposite directions. There is an attempt to eliminate this drawback by slowing down the rotation speed by rotating the blade to a flat surface, but since the rotary blade is flat, it has the drawback that it is easily bent and grass is bitten. It floated up and the cuttability was not good. Further, if the plate thickness is increased to prevent bending, there is a drawback that rotation is blocked when grass pieces, dust, etc. are caught in between.

[Structure of the Invention] (Means and Actions for Solving the Problem) The present invention is arranged in such a manner that the blades 1, 1 are arranged on the outer periphery of the disc portion by stacking them vertically and reciprocally rotating in the opposite directions by driving the engine 13. Symmetrical disk-shaped rotary blades 5, 7 equipped with 3, both rotary blades 5, 7 are
In order to increase the bending rigidity of the disc portion, the outer edge is close to the blade portions 1 and 3, the inner edge is close to the flange portions 51 and 27 that sandwich the center portion, and the height is a predetermined height. Conical recess 5
In addition to forming 7,59 in the center, it is formed with a plate thickness that is the limit allowable for strength.

As a result, the present invention increases the overall rigidity of both rotary blades even when a thin plate material is used, making it difficult to bend with respect to lateral or oblique loads, and preventing dust, grass chips, etc. from being caught. It can be eliminated.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings. That is, two circular rotary blades 5 and 7 having a large number of blade portions 1 and 3 on the outer periphery in FIGS. 1 to 8 are vertically supported and axially supported by the bearing case 9, and the connecting rod 11 is provided. Driven by the engine 13 connected to the bearing case 9 via the drive shaft, it is rotationally driven via the transmission shaft 15 penetrating the connecting rod 11. A grip 17 and a handle 19 are provided in the middle of the connecting rod 11.
The grip 21 is fixed to 19. In the bearing case 9, the rotary shaft 25 is vertically supported by the bearings 23 and 24 via the rotary cylinder 43, and the flange portion 27 at the lower end of the rotary shaft 25 is screwed.
The lower rotary blade 7 is fixed by 29, and the cover 31 is screwed to the lower end of the rotary shaft 25 so as to cover the screw 29. Rotating cylinder
A flange portion 51 is integrally formed on the lower portion of 43, and the upper rotary blade 5 is fixed to the flange portion 51 with a screw 53. The rotary blades 5 and 7 have blade portions 1 and 3 formed on the outer circumference,
The outer edges 56 and 58 are close to the roots of the blades 1 and 3, and the inner edge is the flange
The circular recesses 57 and 59 adjacent to 51 and 27 are formed in a conical shape, and the blade portions 1 and 3 are slightly bent in the direction of the rotary blades facing each other from the horizontal plane as shown in FIGS. 6 and 7. Formed,
At the positions where the blade portions 1 and 3 are overlapped, as shown in FIGS. 3 to 5, the blade portions 1 and 3 are pushed and spread against the elasticity of the blade portions 1 and 3,
The blades come into contact with each other at the tip and the root position of the blade, or are provided with a slight gap at the root position.
The positions where the blade-side edge portions 60 and 62 of the blades 1 and 3 come into contact with each other are point-like, and move along the blade-side edge portions 60 and 62 from the root to the tip with rotation. is there. Then, in the rotary blades 5 and 7 of the present embodiment, with the formation of the circular recesses 57 and 59,
A material is used which has a limit thickness which is allowable in terms of strength, that is, a thickness which is as thin as possible without causing damage.

On the upper part of the rotary shaft 25 and the rotary cylinder 43, splines 61 and 6 respectively.
Swing arms 65 and 67 are engaged via 3. Rotating shaft 25
A crankshaft 69 is axially supported by the bearing case 9 in parallel with the crankshaft 69, and eccentric circular cam plates 73, 75 integrally formed with the crankshaft 69 are provided at symmetrical positions, and the connecting rods are fitted to the outer circumferences. The other ends of 77 and 79 are swing arm 6 respectively.
It is pivotally attached to the tip of 5,67 by shafts 81,83. A bevel gear 41, which engages with the tip of the transmission shaft 15 and is axially supported by the bearing case 9 by a bearing 39, is provided under the crankshaft 69.
Is engaged with the bevel gear 33. The power of the transmission shaft 15 causes the circular cam plates 73, 75 to rotate via the bevel gears 41, 33, the swing arms 65, 67 to swing in the opposite direction, and the blade portion
The rotary blades (5, 7) are reciprocally rotated in opposite directions within a range of one or two teeth (1, 3).

The operator grips the grips 17, 21 with both hands, and drives the engine 9 to reciprocally rotate the rotary blades 5 and 7 in opposite directions at low speed.
By this, the work of cutting grass on the ground is performed.

Even if a load is applied diagonally or laterally to the rotary blades 5 and 7,
The rigidity of the entire rotary blades 5, 7 is increased by the recesses 57, 59, so that the rotary blades 5, 7 do not curve.

Further, the rotary blades 5 and 7 make one reciprocation for one revolution of the crankshaft 69, but the reciprocating motion range is one to two teeth, so the circumferential speed is greatly reduced, and no special reduction mechanism is required.

[Advantage of the Invention] According to the present invention, by rotating two superposed rotary blades reciprocally in opposite directions, it is possible to perform work at low speed without providing a special reduction mechanism, and thus pebble. You can work safely without splashing, etc., and you can mow even soft grass, and by providing the rotary blade with a recess, the overall rigidity of the rotary blade is increased, and even thin materials can be greatly deformed. In addition, it is possible to elastically closely contact only the blade portion with a thin material, and it is possible to press the blade portions against each other by eliminating the biting of grass pieces etc., improving the cutting performance It is a thing.

Incidentally, FIG. 9 shows a conventional example, in which one flat rotary blade is rotated at high speed.

That is, the bearing case 85 has a rotary shaft 89 supported by a bearing 87, and a circular rotary blade 93 having a blade portion 91 on the outer circumference.
Is sandwiched between the upper and lower washers 95 and 97. Washer95,
97 is engaged with the rotating shaft 89 by the spline 99, and the nut 10
It is fixed by 1. A bevel gear 105 is engaged with a bevel gear 103 integrally formed at the upper end of the rotating shaft 89, the bevel gear 105 is axially supported by a bearing 107, and the tip of a transmission shaft 111 penetrating the connecting rod 109 is screwed.

[Brief description of drawings]

1 is a perspective explanatory view of a brush cutter having a rotary blade according to the present invention, FIG. 2 is a side sectional view of an embodiment of the present invention, FIG. 3 is a plan view of essential parts, and FIG. 3 is a side sectional view taken along the line IV-IV of FIG. 3, FIG. 5 is a side sectional view taken along the line VV of FIG. 3, FIG. 6 is a plan view of an essential part in another state, and FIG. 7 is FIG. 7 is a side sectional view taken along line VII-VII of FIG. 8, FIG. 8 is a plan sectional view of the same portion, and FIG. 9 is a side sectional view of a conventional example. 1,3 …… Blade part, 5,7 …… Rotating blade 27,51 …… Flange part 57,59 …… Cavity

Claims (1)

[Scope of utility model registration request] 1. The blades 1, 3 are vertically overlapped with each other and driven by an engine 13 to reciprocally rotate in opposite directions so that the blades 1, 3 are formed on the outer circumference of the disc.
Symmetric disk-shaped rotary blades 5 and 7 equipped with
In Nos. 5 and 7, the outer edge is the blade part to increase the bending rigidity of the disk part.
Flange part 51,27 which is close to 1,3 and whose inner edge holds the center part
And the truncated conical recesses 57 and 59 that are close to the center and have a predetermined height are formed in the center, and that they are formed with a plate thickness that is the maximum allowable strength. The rotary blade of the characteristic brush cutter.