WO2010082347A1

WO2010082347A1 - Rotating blade for mower and mower using the same

Info

Publication number: WO2010082347A1
Application number: PCT/JP2009/050637
Authority: WO
Inventors: 策次山田
Original assignee: 山田機械工業株式会社
Priority date: 2009-01-19
Filing date: 2009-01-19
Publication date: 2010-07-22
Also published as: JPWO2010082347A1

Abstract

A rotating blade (A1) has a holding member (100) mounted to a mounting shaft (14) of a mower and rotated, and also has cord-like cutting members (4(4a)) having base ends held by the holding member (100) and also having head ends extending radially outward from predetermined positions of the holding member (100). The holding member (100) has bodies (120, 130) rotating together with the mounting shaft (14), an operation section (140) mounted to the bodies (120, 130) so as to be movable in the axis direction of the mounting shaft (14) and to be able to be rotated about the mounting shaft (14) relative to the bodies (120, 130), an elastic member (170) for urging the operation section (140) in one direction along the axis direction, a clutch mechanism for preventing relative rotation between the operation section (140) and the bodies (120, 130) when the operation section (140) is held at a predetermined position by elasticity of the elastic member (170) and permitting relative rotation between the operation section (140) and the bodies (120, 130) when the operation section (140) is moved from the predetermined position against the elasticity of the elastic member (170), a reel member (160) mounted to the bodies (120, 130) so as to be rotatable about the mounting shaft (14) and having the cord-like cutting members (4) wound and held thereon, and a transmitting means for rotating the reel member (160) in response to operation for rotation by the operation section (140).

Description

Rotating blade for brush cutter and brush cutter using the same

The present invention relates to a rotary blade for a brush cutter and a brush cutter using the same.

There is a portable power brush cutter as a tool for removing weeds growing on the bank of the field. The brush cutter is configured to transmit, for example, rotational power generated by a small engine to a rotary blade supported at the tip of an operation tube, and an operator can rotate the engine or the rotary blade rotated by the throttle lever. While controlling the rotation, the operation tube is shaken to perform a desired trimming operation.

Rotating blades include nylon cord cutting blades that extend radially from the center. 9 and 10 show an example of such a rotary blade. The rotary blade X1 shown in FIG. 9 is attached to the brush cutter Y, and the nylon cord cutting blade 92 held by the holding member 91 rotates at high speed in the N direction together with the holding member 91, so that weeds and the like It is set as the structure which can be cut | disconnected. According to such a configuration, even if the rotary blade X1 comes into contact with an object that is harder than weeds, such as a stone, a concrete piece, or a guard rail post, the nylon cord cutting blade 92 has an appropriate flexibility. Since it has, it bends flexibly and does not produce a big impact force. Therefore, it can be avoided that the object is crushed and its fragments are scattered around the periphery or the rotary blade X1 itself is damaged.

The rotary blade X2 shown in FIG. 10 has a configuration in which a guide member 93 is additionally provided compared to the rotary blade X1 described above (see Patent Documents 1 and 2). As shown in FIG. 10, the guide member 93 has a disk shape extending outward in the radial direction from the holding member 91, and the rotary blade X <b> 2 has a nylon cord from the outer peripheral edge of the guide member 93. A part of the cutting blade 92 is configured to protrude a predetermined length. According to the rotary blade X2 having such a configuration, during operation of the brush cutter Y, the guide member 93 detects that weeds or the like enter the portion near the base end of the nylon cord cutting blade 92 (near the outer periphery of the holding member 91). In order to prevent this, only the portion near the tip of the nylon cord cutting blade 92 having a relatively high peripheral speed can collide with the weeds or the like and cut it, so that the workability of the brush cutting can be improved.

As the nylon cord cutting blade 92 continues to be used, wear or breakage occurs at the tip, and the length of the portion extending from the outer edge of the guide member 93 becomes shorter. In response to such a situation, it is required to recover the extension length of the nylon cord cutting blade 92 by feeding the nylon cord cutting blade 92 out of the holding member 91. The operation of feeding the nylon cord cutting blade 92 is preferably performed in a state where the engine is stopped and the rotary blade X2 is stationary from the viewpoint of safety and certainty of the feeding operation.

On the other hand, in the rotary blade disclosed in Patent Document 2, as shown in FIG. 3 of the same document, the holding member (100) is a nylon cord winding body around which the nylon cord (4) is wound. (120) and a cover body (130) having a nylon cord lead-out port (131) through which the distal end side of the nylon cord cutting blade (4a) is led out, and tightening the bolt (15) to wind the nylon cord The body and the cover body are integrally fixed to the rotary blade mounting shaft (14). When the brush cutter is used, the nylon cord winding body and the cover body are rotated with the rotation of the rotary blade mounting shaft. When the nylon cord cutting blade is extended, the nylon cord winding body and the cover body can be rotated relative to each other by loosening the bolt after stopping the engine. By rotating, the nylon cord cutting blade can be fed out and its extension length can be adjusted.

However, in the conventional configuration, it is necessary to loosen the bolt when the nylon cord cutting blade is fed out, and the workability is poor.

JP 2005-224144 A International Publication WO 2007/023758

The present invention has been conceived under the above circumstances, and in a rotary blade for a brush cutter for cutting weeds by rotating a cord-like cutting member, the feeding operation of the cord-like cutting member is ensured. It is another object of the present invention to provide a rotary blade for a brush cutter that can be easily performed and a brush cutter using the same.

In order to solve the above problem, the present invention takes the following technical means.

The rotary blade for a brush cutter provided by the first aspect of the present invention includes a holding member that is attached to and rotated by a mounting shaft of the brush cutter, a proximal end side is held by the holding member, and a distal end side is the holding member. A rotary blade for a brush cutter provided with a cord-shaped cutting member extending radially outward from a fixed position of the main body, wherein the holding member is connected to the mounting shaft and rotates integrally with the mounting shaft And an operation unit that is movable with a predetermined stroke in the axial direction of the mounting shaft with respect to the main body unit and is capable of relative rotation around the mounting shaft, and the operation unit in one axial direction. When the elastic member urging the elastic member and the operation portion are in a predetermined position in the stroke by the elastic force of the elastic member, the operation portion and the main body portion are prevented from rotating relative to each other. A clutch mechanism that allows relative rotation between the operation portion and the main body when moved from the predetermined position against the elasticity of the member, and a combination that allows the main body to rotate about the mounting shaft. And a reel member that winds and holds the cord-like cutting member, and a transmission unit that rotates the reel member in response to a rotation operation of the operation unit.

In a preferred embodiment, the clutch mechanism includes a plurality of first engagement portions provided along the rotation direction in the operation portion, and a plurality of second engagements provided along the rotation direction in the main body portion. And the first engagement portion and the second engagement portion engage with each other, thereby preventing relative rotation between the operation portion and the main body portion.

In a preferred embodiment, the plurality of first engaging portions and the plurality of second engaging portions are each provided at a constant angular pitch.

In a preferred embodiment, the operation unit is positioned higher than the main body unit.

In a preferred embodiment, the operation section is allowed to move relative to the main body by moving away from the main body from the predetermined position.

In another preferred embodiment, the operation portion is allowed to move relative to the main body portion by being moved closer to the main body portion from the predetermined position.

In a preferred embodiment, the transmission means includes a configuration in which a base end side of the cord-shaped cutting member is fixed to the operation portion.

In a preferred embodiment, the guide member further includes a guide member extending radially outward from the holding member, and the cord-shaped cutting member is a part of the distal end side in a state of extending radially outward. Protrudes from the outer edge of the guide member.

In a preferred embodiment, the guide member is supported so as to be rotatable about the rotation axis with respect to the holding member.

According to a preferred embodiment, the cord-shaped cutting member is made of nylon.

The brush cutter provided by the second aspect of the present invention includes an operation tube in which a transmission shaft to which a rotation output of a drive source is transmitted, a rotary blade mounting portion formed at a tip of the operation tube, A mounting shaft that rotates by transmitting the rotational force of the transmission shaft in the rotating blade mounting portion, and the mounting blade is mounted with the rotating blade according to the first aspect of the present invention. It is a feature.

1 is an overall perspective view of an example of a rotary blade for a brush cutter and a brush cutter using the same according to the present invention. It is a principal part enlarged view of FIG. FIG. 3 is a cross-sectional view of a principal part taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view of a principal part taken along line IV-IV in FIG. 3. FIG. 4 is a cross-sectional view of main parts similar to FIG. It is principal part sectional drawing similar to FIG. 3 of the other example of the rotary blade for brush cutters which concerns on this invention. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 7 is a cross-sectional view of the main part similar to FIG. It is the whole rotary blade for brush cutters, and the whole perspective view of an example of a brush cutter using the same. It is the whole rotary blade for brush cutters, and the whole perspective view of an example of a brush cutter using the same.

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 to 5 show an example of a rotary blade for a brush cutter and a brush cutter using the same according to the present invention. As clearly shown in FIG. 1, in the brush cutter B, a small engine 11 as a drive source is connected to the proximal end side of the operation tube 12, and the rotation output is inserted into the operation tube 12. It is configured to be transmitted to the distal end portion of the operation tube via the transmitted transmission shaft 13. As the small engine 11, an engine having a displacement of about 25 cc is used in consideration of the portability of the operator. The small engine 11 may be directly attached to the base end of the operation tube 12, or an engine mounted on a backpack frame, for example, may be connected via a flexible transmission shaft. As clearly shown in FIG. 3, the rotary blade mounting shaft 14 is supported on the gear case 16 at the tip of the operation tube 12, and the rotary blade mounting shaft 14 and the transmission shaft 13 are configured with a bevel gear mechanism (not shown). It is linked by. A rotary blade holder 14b that receives the upper surface of the center portion of the rotary blade A1, which will be described later, is integrally fitted and fixed to the rotary blade mounting shaft 14 by, for example, spline fitting, and a screw extending in the axial direction is attached to the shaft end. A hole 14a is formed.

The rotary blade A1 characterized by the present invention is attached to the rotary blade mounting shaft 14 with compatibility with a general metal rotary blade.

As shown in FIGS. 2 and 3, the rotary blade A1 is attached to the rotary blade mounting shaft 14 and rotated, and holds a nylon cord cutting blade 4a as an example of a cord-like cutting member. And a guide member 200 supported so as to be rotatable about the rotation axis (same axis as the rotary blade mounting shaft 14) with respect to the holding member 100.

In the present embodiment, the holding member 100 includes a lower support piece 110 that is externally fitted to the rotary blade mounting shaft 14, a nylon cord wound body 120 that is externally fitted to the lower support piece 110, and this nylon cord wound body. An intermediate plate 130, an operation cover body 140 (operation unit), and an upper support piece 150 that are sequentially stacked on 120 are provided.

The lower support piece 110 has a center boss portion 111 and an outward flange portion 112, and is made of a material having a predetermined strength such as aluminum. The nylon cord wound body 120 includes an inward flange portion 121 in which a center hole is fitted around the upper outer periphery of the center boss portion 111 of the lower support piece 110, and an annular housing portion 122 connected to the outer periphery of the inward flange portion 121. For example, it is formed by resin integral molding. The housing portion 122 is surrounded by a cylindrical inner peripheral wall 122a, a disk-shaped bottom wall 122b, and a cylindrical outer peripheral wall 122c, and has a groove shape that opens upward.

A drum-shaped reel member 160 for winding and holding a nylon cord 4 described later is mounted on the housing portion 122. The reel member 160 has a slight gap between the inner peripheral wall 122a, the bottom wall 122b, and the intermediate plate 130 of the housing portion 122 when mounted, whereby the nylon cord winder 120 is attached to the reel member 160. On the other hand, it can rotate around its rotation axis (same axis as the rotary blade mounting shaft 14).

The intermediate plate 130 has a substantially disk shape and is made of a material having a predetermined strength such as aluminum. A plurality of engagement convex portions 131 (second engagement portions) are provided on the outer peripheral edge of the intermediate plate 130. These engagement protrusions 131 are provided at a constant angular pitch along the circumferential direction (the rotation direction of the holding member 100), as shown in FIG. 4, and in this embodiment, at a 60 ° pitch. A total of six engaging projections 131 are provided. The significance of these engaging projections 131 will be described later.

The upper support piece 150 has a disc portion 151, a cylindrical peripheral wall portion 152, and an outward flange portion 153, and is a disc against the rotary blade holder 14 b fitted and fixed to the rotary blade mounting shaft 14. The part 151 is externally fitted. The upper support piece 150 is made of a material having a predetermined strength such as aluminum. The inward flange portion 121 of the nylon cord winding body 120 and the intermediate plate 130 are sandwiched between the outward flange portion 112 of the lower support piece 110 and the disc portion 151 of the upper support piece 150, and thereby, The nylon cord winding body 120 and the intermediate plate 130 are integrally connected to the rotary blade mounting shaft 14 via both

support pieces

110 and 150. The nylon cord wound body 120 and the intermediate plate 130 constitute a main body referred to in the present invention. A cylindrical flange 154 is provided on the inner periphery of the disk portion 151 of the upper support piece 150, and the inner periphery of the intermediate plate 130 is fitted to the outer periphery of the cylindrical flange 154. The support piece 150 and the intermediate plate 130 are aligned.

The operation cover body 140 has a substantially cylindrical shape, and is disposed above the nylon cord winding body 120 so as to close an upper open portion of the housing portion 122 of the nylon cord winding body 120. In the present embodiment, the operation cover body 140 has an outer peripheral wall portion 141 and an inner peripheral wall portion 142. The outer peripheral wall portion 141 is externally fitted to the outer peripheral wall 122c of the housing portion 122 of the nylon cord winding body 120 through a slight gap, and the inner peripheral wall portion 142 is the outward flange portion 153 of the upper support piece 150. Is fitted through a slight gap. Thereby, the operation cover body 140 can move in the axial direction of the rotary blade mounting shaft 14 relative to the nylon cord winding body 120 or the upper support piece 150 and can rotate around the rotary blade mounting shaft 14. . In FIG. 3, the operation cover body 140 is located at the downward movement position in the axial movement stroke.

A plurality of engagement convex portions 143 (first engagement portions) are provided on the inner peripheral edge of the inner peripheral wall portion 142 of the operation cover body 140. These engagement convex portions 143 are provided at a constant angular pitch along the circumferential direction (the rotation direction of the holding member 100), as shown in FIG. 4, and in this embodiment, at a 60 ° pitch. A total of six engaging projections 143 are provided. The operation cover body 140 having the above configuration is formed by, for example, resin integral molding.

The plurality of engaging protrusions 143 engage with the plurality of engaging protrusions 131 of the intermediate plate 130 when the operation cover body 140 is in the downward movement position in the axial movement stroke. Thereby, relative rotation of the operation cover body 140 with respect to the intermediate plate 130 is prevented. On the other hand, when the operation cover body 140 is in the upward movement position in the axial movement stroke, as shown in FIG. 5, the plurality of engagement convex portions 143 of the operation cover body 140 are formed by the plurality of intermediate plate 130. It does not engage with the engaging projection 131. At this time, relative rotation of the operation cover body 140 with respect to the intermediate plate 130 is allowed. In the present embodiment, the clutch mechanism referred to in the present invention is constituted by a plurality of engaging

projections

131 and 143.

As shown in FIG. 3, an elastic member 170 made of, for example, a compression coil spring is interposed between the outward flange portion 153 of the upper support piece 150 and the engagement convex portion 143 of the operation cover body 140. . The operation cover body 140 is constantly urged downward in the figure by the elastic force of the elastic member 170, and is normally positioned at the downward movement position. At this time, as described above, the engagement convex portion 143 of the operation cover body 140 and the engagement convex portion 131 of the intermediate plate 130 are engaged, and the operation cover body 140 for the nylon cord winding body 120 or the intermediate plate 130 is engaged. Is prevented from rotating. On the other hand, when the operation cover body 140 is moved away (upward) from the nylon cord winding body 120 or the intermediate plate 130 against the elasticity of the elastic member 170, as described above with reference to FIG. The engagement protrusion 143 and the engagement protrusion 131 are not engaged. At this time, rotation of the operation cover body 140 with respect to the nylon cord winding body 120 or the intermediate plate 130 is allowed.

As shown in FIGS. 3 and 4, a pair of adjacent holes 144 are formed at appropriate positions of the operation cover body 140, and the holes 144 are arranged around the center in the longitudinal direction of the series of long nylon cords 4. Through the two nylon cords 4, the nylon cord 4 is accommodated in the housing portion 122 of the nylon cord winding body 120. In the present embodiment, the reel member 160 is attached to the housing portion 122 as described above, and the nylon cord 4 is wound and held on the nylon cord winding body 120 via the reel member 160. By doing in this way, the nylon cord 4 which became two substantially is fixed to the operation cover body 140 by the base end side, and the state wound up appropriately is completed. The two nylon cords 4 are respectively led out to the outside from nylon cord lead-out ports 123 opened at two locations so as to face the outer peripheral wall 122c of the nylon cord winding body 120 in the diametrical direction. The tip side of this will function as the nylon cord cutting blade 4a. In this embodiment, the nylon cord outlet 123 is provided with an aluminum cylindrical collar 125 having excellent wear resistance in a through-hole 124 formed in the outer peripheral wall 122c of the nylon cord winding body 120. It is configured. Thereby, the nylon cord cutting blade 4 a is led out of the nylon cord winding body 120 through the hole of the cylindrical collar 125.

As understood from FIG. 5, when the operation cover body 140 is rotated relative to the nylon cord winding body 120, the reel member 160 and the nylon cord 4 wound and held on the reel member 160 are integrated with the operation cover body 140. And is rotated relative to the nylon cord winding body 120. That is, the reel member 160 can be rotated relative to the nylon cord winding body 120 in accordance with the rotation operation of the operation cover body 140, and the length of the nylon cord cutting blade 4a led out from the nylon cord lead-out port 123 can be increased. Can be adjusted. Such a configuration corresponds to an example of the transmission means in the present invention. Here, when the operation cover body 140 is rotated relative to the nylon cord winding body 120 in the nylon cord winding direction, the extension length of the nylon cord cutting blade 4a can be shortened. When the relative rotation is performed in the feeding direction, the extending length of the nylon cord cutting blade 4a can be extended. The transmission means has a function of rotating the reel member 160 in the operation direction in accordance with the rotation operation of the operation cover body 140, and the nylon cord 4 wound and held on the reel member 160 as in the present embodiment. In addition to a configuration in which a part of the operation cover body 140 is connected to the operation cover body 140, a rotational operation force of the operation cover body 140 can be mechanically transmitted to the reel member 160 and rotated in the operation direction.

The guide member 200 includes a center member 210 having a center tube portion 211 and an outward flange 212 extending from the lower end of the center tube portion 211, and a center portion by a rivet or the like so as to overlap the outward flange 212 of the center member 210. The disc portions 220 are connected to each other, and are formed to have a disc shape as a whole. As shown in FIGS. 2 and 3, the outer periphery of the disc part 220 (the outer edge of the guide member 200) extends radially outward from the holding member 100 described above. The outer ring 231 of the bearing 230 is press-fitted and held on the inner surface of the central cylindrical portion 211 of the central member 210 in the guide member 200. The guide member 200 may be formed by integrating both the central member 210 and the disk portion 220 with resin, or may be formed by integral resin molding. In order to reduce the weight, the guide member 200 is preferably formed of resin, but the material is not limited thereto.

The attachment of the rotary blade A1 to the rotary blade attachment shaft 14 is performed as follows. First, the holding member 100 in a state in which the lower support piece 110, the nylon cord winding body 120, the intermediate plate 130, the operation cover body 140, and the upper support piece 150 are assembled, and the central boss portion 111 of the lower support piece 110 is used as a rotary blade. The rotary blade mounting shaft 14 is held by being externally fitted to the mounting shaft 14. Next, the guide member 200 is held in a state where the inner ring 232 of the bearing 230 press-fitted and held against the guide member 200 is abutted against the lower end of the central boss portion 111 of the lower support piece 110. Next, the bolt 15 is screwed into the screw hole 14 a provided at the shaft end of the rotary blade mounting shaft 14 while being inserted into the inner ring 232 of the bearing 230 and the center boss 111 of the support piece 110. Accordingly, the upper support piece 150 disk portion 151, the center boss portion 111 of the lower support piece 110, and the inner ring of the bearing 230 are provided between the rotary blade mounting shaft 14 or the rotary blade retainer 14 b and the head 15 a of the bolt 15. 232 is clamped and fixed. At the same time, the inward flange portion 121 of the nylon cord winding body 120 and the intermediate plate 130 are sandwiched between the disc portion 151 of the upper support piece 150 and the outward flange portion 112 of the lower support piece 110. The nylon cord winding body 120 and the intermediate plate 130 are fixed to each other so as not to rotate relative to each other. In this state, the nylon cord cutting blade 4a is adjusted so that the maximum extension length from the outer edge of the guide member 200 is, for example, 30 to 50 mm.

When the rotary blade A1 is attached to the rotary blade attachment shaft 14 as described above, the holding member 100 or the nylon cord cutting blade 4a is positioned higher than the guide member 200 as the rotary blade attachment shaft 14 rotates. On the other hand, the guide member 200 is rotated freely with respect to the rotary blade mounting shaft 14 or the holding member 100 by the bearing 230. This means that the guide member 200 does not rotate in response to the rotational driving force of the engine 11 of the brush cutter B even during the rotation of the holding member 100 or the nylon cord cutting blade 4a, and makes contact with an external object. Even so, it means that the stationary state can be maintained.

The dimensions of each part of the rotary blade A1 are set such that, for example, the outer diameter of the holding member 100 is about 100 mm and the outer diameter of the guide member 200 is about 300 to 400 mm, but these dimensions are not limited.

Next, the operation of the brush cutter B or the rotary blade A1 will be described.

When performing the brush cutting operation using the brush cutter B, for example, if the throttle opening of the engine 11 is increased by operating the throttle lever or the like, the rotary blade A1 is held by the rotational output of the engine 11. The member 100 or the nylon cord cutting blade 4a is rotated in the N direction in FIG. By adjusting the throttle opening of the engine 11, the rotational speed of the nylon cord cutting blade 4a can be adjusted. The rotational output of the engine 11 is decelerated from the transmission shaft 13 by a bevel gear (not shown) in the gear case 16, and is transmitted to the holding member 100 or the nylon cord cutting blade 4a via the rotary blade mounting shaft 14. The number of rotations of the holding member 100 or the nylon cord cutting blade 4a reaches, for example, 5,000 to 6,300 rpm. Since the dimension from the rotation center of the rotary blade A1 to the tip of the nylon cord cutting blade 4a is, for example, about 180 mm, the peripheral speed of the tip of the nylon cord cutting blade 4a is easily over 400 km / h. When the rotary blade A1 is moved along the ground, a relatively soft and thin object such as weeds comes into contact with the peripheral edge of the guide member 200, or before that, a nylon cord that turns at a high speed as described above. It receives an intense collision from the lateral direction by the cutting blade 4a and is cut without difficulty by the impact. The nylon cord cutting blade 4a has a diameter of about 3 mm at the maximum, the length of the portion extending from the outer edge of the guide member 200 is about 30 to 50 mm, and is lightweight, but the peripheral speed of the tip portion is as described above. Because it is extremely fast, it has enough kinetic energy to cut the stems of soft weeds and the like.

When the rotary blade A1 that moves while the holding member 100 or the nylon cord cutting blade 4a rotates at a high speed as described above contacts a relatively small hard object such as a pebbles or a bolt, the nylon cord cutting blade 4a Although it collides with a small, hard external object, there is not enough kinetic energy to blow off such a small external object excessively. Further, since the impact at the time of collision is absorbed by the nylon cord cutting blade 4a being bent and deformed, the rotary blade A1 is not damaged by the impact, and the holding member 100 or the nylon cord cutting blade 4a is rotated. There is no instantaneous drop in numbers. Therefore, the nylon cord cutting blade 4a once bent and deformed returns to the original protruding state by centrifugal force at the next moment. Thus, even if the rotary blade A1 configured as described above is in contact with small external objects such as pebbles and bolts, there is no risk of flipping them at high speed, and there is no risk of breakage due to impact. The high speed rotation of the nylon cord cutting blade 4a is maintained and the continuous cutting action is continued.

In the use state where the holding member 100 or the nylon cord cutting blade 4a is rotated at a high speed, the operation cover body 140 of the holding member 100 is always urged downward by the elastic member 170, as shown in FIG. The state in the downward movement position is maintained. At this time, the engagement convex portion 143 of the operation cover body 140 and the engagement convex portion 131 of the intermediate plate 130 are engaged, and the operation cover body 140 or the reel member 160 with respect to the nylon cord winding body 120 and the intermediate plate 130 are engaged. The relative rotation of is prevented. Therefore, even if the nylon cord cutting blade 4a is rotated at a high speed, the length of the portion extending from the outer edge of the guide member 200 is maintained substantially constant.

As the nylon cord cutting blade 4a continues to be used, the tip portion is worn or damaged, and the length of the portion extending from the outer edge of the guide member 200 becomes shorter. In such a case, when the engine is stopped and the rotary blade A1 is stopped and the operation cover body 140 is pulled up, the mutual engagement state between the engagement

convex portions

143 and 131 is released as shown in FIG. Thus, the operation cover body 140 and the nylon cord winding body 120 or the intermediate plate 130 are in a state in which relative rotation is allowed. Here, when the operation cover body 140 is rotated relative to the nylon cord winding body 120 in the nylon cord feeding direction, the extension length of the nylon cord cutting blade 4a can be extended.

In the present embodiment, the operation cover body 140 can be allowed to rotate relative to the nylon cord winding body 120 by a simple operation such as lifting the operation cover body 140 and moving it upward, and the nylon cord cutting blade 4a. The extension length of can be adjusted. Therefore, the conventional troublesome operation of loosening the bolt 15 is not necessary, and the workability of adjusting the extension length of the nylon cord cutting blade 4a is improved.

Further, since the engaging

convex portions

143 and 131 are provided at a constant angular pitch, the extension length of the nylon cord cutting blade 4a can be adjusted for each substantially constant length (for example, about 30 mm). It is. According to such a configuration, dimensional management in adjusting the extension length of the nylon cord cutting blade 4a becomes easy, and the workability of the extension length adjustment becomes better.

In the holding member 100 of the rotary blade A1, the operation cover body 140 is disposed above the nylon cord winding body 120. For this reason, even if the rotary blade A1 unintentionally contacts the ground during the mowing work, the operation cover body 140 does not directly contact the ground. Therefore, during the mowing operation, the operation cover body 140 does not unduly move in the axial direction against the elasticity of the elastic member 170, and the nylon cord winding body 120 and the operation cover body 140 are relatively rotated. The state of blocking is reliably maintained.

Further, in the rotary blade A1, the portion rotated by the output of the engine 11 of the brush cutter B is only the holding member 100 or the nylon cord cutting blade 4a as described above. By making the holding member 100 made of resin, the weight of the holding member 100 or the nylon cord cutting blade a can be as low as 150 to 200 g. Therefore, the peripheral speed of the nylon cord cutting blade 4a can be further increased and the high-speed rotation state can be maintained without burdening the small engine 11.

The guide member 200 that is not rotated by the rotational output of the engine 11 is positioned below the holding member 100 or the nylon cord cutting blade 4a. Therefore, negative pressure is not generated between the guide member 200 and the ground, and negative pressure is generated between the guide member 200 and the ground, and the rotary blade is attracted to the ground as in the conventional general metal rotating blade. And the problem that the rotating blade in the high-speed rotating state contacts the ground does not occur. In the rotary blade A1, the guide member 200 may come into contact with the ground. Even in such a case, since the guide member 200 does not rotate at a high speed, the rotation of the rotating portion is not decelerated or the pebbles on the ground are blown off.

The diameter of the guide member 200 and the extension length of the nylon cord cutting blade 4a from the outer edge of the guide member 200 can be variously changed. For example, the diameter of the guide member 200 is set to about 300 to 400 mm and the outer diameter of the guide member 200 is extended about 50 to 150 mm with respect to the outer periphery of the holding member 100 to extend the nylon cord cutting blade 4a. A configuration in which the length is about 30 to 100 mm is also possible. In this case, the peripheral speed of the nylon cord cutting blade 4a reaches about 650 km / h. If such a rotary blade A1 is used, since the diameter of the circular arc drawn by the nylon cord cutting blade 4a is large and the peripheral speed thereof is fast, the brushing operation of a wide area can be performed very efficiently.

Further, in the rotary blade A1, the nylon cord 4 is led out to the outside through a nylon cord outlet 123 to which a cylindrical collar 125 having wear resistance is attached. Therefore, even if the nylon cord cutting blade 4a is rotated at a high speed during the mowing operation, the nylon cord outlet 123 is prevented from being worn by contact with the nylon cord 4, and as a result, the nylon cord outlet 123 is provided. Further, durability of the nylon cord wound body 120 is improved.

In addition, although the rotary blade A1 is configured using two nylon cords 4, the number of nylon cords 4 may be larger than this. For example, the four nylon cords 4 can also be configured to be led out to the outside from nylon cord outlets 123 provided evenly allocated to four locations on the outer peripheral wall 122c of the nylon cord winding body 120, respectively. When the number of nylon cords 4, that is, the number of nylon cord cutting blades 4a is increased in this way, weeds can be cut accurately even when the entire rotary blade A1 is moved relatively quickly. Work can be performed more efficiently.

6 to 8 show other examples of the rotary blade for a brush cutter according to the present invention. 6 to 8, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and description thereof will be omitted as appropriate.

In the rotary blade A2 shown in FIG. 6, the guide member 200 is provided so as not to rotate relative to the holding member 100. Further, the operation cover body 140 is configured to prevent relative rotation with the nylon cord winding body 120 or the intermediate plate 130 when the operation cover body 140 is in the upward movement position of the axial movement stroke. And the rotary blade A2 has various design changes compared with the rotary blade A1 of the said embodiment with these changes.

In the rotary blade A2, the nylon cord winding body 120 of the holding member 100 has a disk portion 126 that extends radially outward from the lower end of the outer peripheral wall 122c, and the guide member 200 overlaps the disk portion 126. Thus, the vicinity of the center is constituted by the disc part 220 connected by rivets or the like. As a result, the guide member 200 is in an integrally connected state with the holding member 100 and rotates as the holding member 100 rotates.

The operation cover body 140 has an annular concave step portion 145 formed on the inner peripheral lower surface thereof, and an elastic member 170 is interposed between the concave step portion 145 and the intermediate plate 130. The upper movement of the operation cover body 140 is restricted by the upper surface of the operation cover body 140 coming into contact with the outward flange portion 153 of the upper support piece 150. In the state shown in FIG. 6, the operation cover body 140 is in the upward movement position in which the upper surface near the inner side is brought into contact with the outward flange portion 153 of the upper support piece 150 by the elasticity of the elastic member 170. At this time, as shown in FIGS. 6 and 7, the engagement convex portion 143 of the operation cover body 140 is engaged with the engagement convex portion 131 of the intermediate plate 130, and the operation cover body 140 with respect to the intermediate plate 130 is engaged. Relative rotation is blocked.

When the operation cover body 140 is moved close to the nylon cord winding body 120 or the intermediate plate 130 against the elastic force of the elastic member 170 (downward movement), as shown in FIG. The engagement state with the mating protrusion 131 is released. At this time, rotation of the operation cover body 140 with respect to the nylon cord winding body 120 or the intermediate plate 130 is allowed.

The rotary blade A2 does not include the rotary blade holder 14b of the above embodiment. On the other hand, the upper support piece 150 has a cylindrical shaft portion 155 extending in the axial direction on the inner periphery, and the cylindrical shaft portion 155 is fitted to the rotary blade mounting shaft 14. Further, a cylindrical flange 132 is provided on the inner periphery of the intermediate plate 130, and this cylindrical flange 132 is fitted to the upper outer periphery of the lower support piece 110, whereby the lower support piece 110 and the intermediate plate are fitted. Centering with 130 is performed.

In the rotary blade A2 of the present embodiment, when the extension length of the nylon cord cutting blade 4a is adjusted, the operation cover body 140 is pushed down and moved down to perform a simple operation on the nylon cord winding body 120. The operation cover body 140 can be allowed to rotate relatively. Therefore, the conventional troublesome operation of loosening the bolt 15 is not necessary, and the workability of adjusting the extension length of the nylon cord cutting blade 4a is improved.

In addition, regarding the configuration of the rotary blade A2 that is the same as or similar to the rotary blade A1 of the above-described embodiment, the same effect as described above for the rotary blade A1 can be enjoyed. Further, in the rotary blade A2, since the guide member 200 is provided integrally with the holding member 100, the overall structure can be simplified. This is suitable for reducing the size of the rotary blade A2.

The present invention is not limited to the embodiment described above. All changes in the specific configuration of the rotary blade for brush cutter and each part of the brush cutter using the same within the scope of the matters described in each claim are included in the scope of the present invention.

Claims

A holding member that is attached to the attachment shaft of the brush cutter and is rotated;
A cord-like cutting member having a proximal end side held by the holding member and a distal end side extending radially outward from a fixed position of the holding member;
The holding member is connected to the mounting shaft and rotates integrally with the mounting shaft;
An operation unit that is movable with a predetermined stroke in the axial direction of the mounting shaft with respect to the main body, and is combined to be capable of relative rotation around the mounting shaft;
An elastic member for urging the operating portion in one axial direction;
When the operation portion is at a predetermined position in the stroke by the elasticity of the elastic member, the operation portion and the main body portion are prevented from rotating relative to each other, and the operation portion resists the elasticity of the elastic member. A clutch mechanism that allows relative rotation between the operation portion and the main body when moved from
A reel member that is combined so as to be rotatable about the attachment shaft with respect to the main body, and winds and holds the cord-shaped cutting member;
A rotary blade for a brush cutter, comprising: a transmission unit that rotates the reel member in accordance with a rotation operation of the operation unit.
The clutch mechanism includes a plurality of first engagement portions provided along the rotation direction in the operation portion, and a plurality of second engagement portions provided along the rotation direction in the main body portion. And
The rotary blade for a brush cutter according to claim 1, wherein the first engagement portion and the second engagement portion engage with each other to prevent relative rotation between the operation portion and the main body portion.
The rotary blade for a brush cutter according to claim 2, wherein the plurality of first engaging portions and the plurality of second engaging portions are respectively provided at a constant angle pitch.
The rotary blade for a brush cutter according to any one of claims 1 to 3, wherein the operation unit is positioned higher than the main body unit.
The rotary blade for a brush cutter according to claim 4, wherein the operation unit is allowed to move relative to the main body by moving away from the predetermined position with respect to the main body.
The rotary blade for a brush cutter according to claim 4, wherein the operation unit is allowed to move relative to the main body by moving the operation unit closer to the main body from the predetermined position.
The rotary blade for a brush cutter according to claim 1, wherein the transmission means includes a configuration in which a base end side of the cord-like cutting member is fixed to the operation portion.
A guide member extending radially outward from the holding member;
The rotary blade for a brush cutter according to claim 1, wherein a part of the tip end side of the cord-shaped cutting member protrudes from an outer edge portion of the guide member in a state of extending outward in the radial direction.
The rotary blade for a brush cutter according to claim 8, wherein the guide member is supported so as to be rotatable about the rotation axis with respect to the holding member.
The rotary blade for a brush cutter according to claim 1, wherein the cord-shaped cutting member is made of nylon.
An operation tube in which a transmission shaft for transmitting the rotational output of the drive source is inserted;
A rotary blade attachment portion formed at the tip of the operation tube, and an attachment shaft that rotates when the rotational force of the transmission shaft is transmitted at the rotary blade attachment portion,
A brush cutter, wherein the rotary blade according to any one of claims 1 to 10 is attached to the attachment shaft.