JPWO2013038497A1 - Rotary blade for mower and mower using the same - Google Patents

Abstract

The rotary blade is attached to the rotary blade attachment shaft 14 of the mower and rotated, and the proximal end side is held by the holding member 100, and the distal end side is in the radial direction from the lead-out hole 123 provided in the holding member 100. A cord-shaped cutting member 4a led out to the outside; and a guide member 200 that can be rotated relative to the holding member 100 at the lower center of the holding member 100 with the rotation axis as a center. 123 is inclined with respect to the inner end so that the outer end is lower. The guide member 200 has a disk shape having a general portion and an outer peripheral portion displaced upward with respect to the general portion, and a plurality of concave portions 240 are formed on the outer periphery thereof.

Description

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

  There is a portable power mower as a tool for removing weeds growing on the bank of a field. This mower is of a type also called a brush cutter, and is configured to transmit the rotational power generated by a small engine to a rotary blade supported at the tip of an operation tube. While controlling the rotation of the engine or the rotary blade rotated by the engine, a desired mowing operation is performed by swinging the operation tube.

  As a rotary blade suitable for this type of portable power mower, there is one disclosed in Patent Document 1. The rotary blade shown in this document is a nylon cord (cord-like cutting member) type rotary blade proposed by the inventor of the present application, and is attached to the rotary blade mounting shaft of a mower and rotates together with the rotary blade mounting shaft. In addition to the holding member that holds the cord-shaped cutting member, the holding member is characterized in that it is equipped with a guide member that is rotatably supported around its rotation axis.

  In the rotary blade of Patent Document 1 having the above configuration, since the rotational force from the rotary blade mounting shaft is not transmitted to the guide member, for example, when the guide member is in contact with the ground, the guide member does not rotate, Only the holding member rotates at high speed. The cutting target such as weeds is effectively cut by the distal end portion of the cord-like cutting member that turns at high speed because the guide member prevents the guide member from entering inward from the outer periphery of the guide member. It has a function.

  However, in the rotary blade of Patent Document 1, since the guide member is supported with respect to the holding member via the bearing, there is no gap between the cord-shaped cutting member extending from the holding member and the upper surface of the guide member. I won't. This has led to the following problems.

  In other words, during operation, the cord-like cutting member turns at high speed in the air, but the weeds to be cut extend from the ground, so that the rotating blade is moved along the ground in a situation where weeds etc. are densely growing. When the needle is moved at a relatively high speed, the phenomenon that the tip of the nylon cord that contacts the weeds is moved downward as the weeds fall and is momentarily displaced downward, and may be struck against the guide member continuously. As a result, vibration is generated in the entire rotary blade, and the rotational speed of the rotary blade may be reduced to reduce cutting efficiency.

  Moreover, as weeds, there are climbing weeds such as morning glory, as well as upright ones whose stems extend vertically from the ground. Such a climbing weed vine flexes flexibly with a diameter of 2 to 3 mm, extends over several meters so as to scoop the ground or wrap around other weeds, and against the pulling force It has a strong nature. In the case of such climbing weeds, in the rotary blade of Patent Document 1, even if the cord-like cutting member that turns at high speed hits the vine, the vine is not cut, and the holding member remains entangled with the cord-like cutting member. As a result of the rotation, the winding member may be wound between the holding member and the guide member, making it impossible to continue the mowing operation.

International Publication WO 2007/023758

  The present invention has been conceived under the circumstances described above, and in a rotary blade for a mower equipped with a guide member so as to cut weeds or the like at the tip of a rotating cord-like cutting member, It is an object of the present invention to provide a rotary blade for a mower capable of performing efficient cutting work and a mower using the same.

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

  The rotary blade for a mower provided by the first aspect of the present invention includes a holding member that is attached to a rotary blade mounting shaft of a mower and is rotated, a proximal end side is held by the holding member, and a distal end side is the holding portion A cord-shaped cutting member that is led out radially outward from a lead-out hole provided in the member, and a guide member that can rotate relative to the holding member at the lower part of the holding member about its rotation axis. And the lead-out hole is inclined so that the outer end is lower than the inner end.

  In a preferred embodiment, the guide member has a disk shape.

  A rotary blade for a mower provided by the second aspect of the present invention includes a holding member that is attached to a rotary blade mounting shaft of a mower and is rotated, a proximal end side is held by the holding member, and a distal end side is the holding portion A cord-shaped cutting member that is led out radially outward from a lead-out hole provided in the member, and a guide member that can rotate relative to the holding member at the lower part of the holding member about its rotation axis. The guide member has a disk shape having a general part and an outer peripheral part displaced upward with respect to the general part.

  In preferable embodiment, the said general part is flat form, and the said outer peripheral part is flat form displaced upwards with respect to the said general part.

  In a preferred embodiment, the radial width of the outer peripheral portion is 1/3 to 1/20 of the radius of the guide member.

  The rotary blade for mower provided by the third aspect of the present invention includes a holding member that is attached to a rotary blade mounting shaft of the mower and is rotated, a proximal end side is held by the holding member, and a distal end side is a radial direction. A cord-like cutting member led out to the outside, and a guide member that can rotate relative to the holding member at the lower part of the holding member around its rotation axis, the guide member having an outer periphery A plurality of recesses are formed on the surface.

  In a preferred embodiment, the bottoms of the plurality of recesses are smoothly curved.

  In the rotary blade for mowers according to each of the above-mentioned side surfaces, the guide member is preferably made of resin.

  In the rotary blade for a mower according to each of the above-described side surfaces, the cord-shaped cutting member is preferably made of nylon.

  In the rotary blade for a mower according to each of the above-mentioned side surfaces, preferably, the holding member is connected to the rotary blade mounting shaft and rotates integrally with the rotary blade mounting shaft, and the base end side of the cord-shaped cutting member is connected to the rotary blade mounting shaft. A main body part that is housed in a wound state, and is positioned higher than the main body part, can be moved with a predetermined stroke in the axial direction of the rotary blade mounting shaft, and can be operated to rotate relative to the rotary blade mounting shaft. Combined, the operation part to which the base end side end of the cord-like cutting member is connected, an elastic member that urges the operation part in one axial direction, and the operation part by the elasticity of the elastic member When the operation unit and the main body unit are prevented from rotating relative to each other at a predetermined position in the stroke, the operation unit is moved from the predetermined position against the elasticity of the elastic member. Comprising a clutch mechanism that permits relative rotation between the work portion and the body portion.

  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.

  A mower provided by the fourth aspect of the present invention includes a power source and a rotary blade mounting shaft that is rotationally driven by the power of the power source. The rotary blade for mowers which concerns on the 1st-3rd side surface is attached.

1 is an overall perspective view of an example of a rotary blade for a mower according to an embodiment of the present invention and a mower using the same. It is a longitudinal cross-sectional view of the rotary blade for mowers concerning one Embodiment of this invention. It is a longitudinal cross-sectional view for effect | action description of the rotary blade for mowers shown in FIG. It is sectional drawing which follows the IV-IV line of FIG. It is a partial top view for an effect | action description of the rotary blade for mowers shown in FIG. It is a longitudinal cross-sectional view of the rotary blade for mowers concerning other embodiment of this invention. It is a principal part top view of the rotary blade for mowers concerning other embodiment of this invention. It is a principal part top view of the rotary blade for mowers concerning other embodiment of this invention. It is an expanded sectional view which follows the IX-IX line of FIG.

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

  1 to 5 show an embodiment of a rotary blade for a mower according to the present invention and a mower using the same. As clearly shown in FIG. 1, in the mower 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. 2 and 3, a 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 connected to a bevel gear mechanism ( (Not shown). A spline is formed on the outer periphery of the rotary blade mounting shaft 14, and a screw hole 14a extending in the axial direction is formed at the shaft end.

  A rotary blade A1 characterized by the present invention is attached to the rotary blade mounting shaft 14.

  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 that can rotate relative to the holding member 100 around its rotation axis (same axis as the rotary blade mounting shaft 14).

  In the present embodiment, the holding member 100 is supported so as to be sandwiched between the support piece 150 that is spline-fitted to the rotary blade mounting shaft 14, the lower piece 110, and the support piece 150 and the lower piece 110. A nylon cord storage case 120 and a cover body 140 (operation unit) that is overlaid on the nylon cord storage case 120. The lower piece 110 is externally fitted to a mounting bolt 15 that is screwed into the screw hole 14 a of the rotary blade mounting shaft 14.

  The support piece 150 includes a boss portion 151 having a spline hole 151a that is spline-fitted so as not to rotate relative to the rotary blade mounting shaft 14, a flange portion 152 that extends outward in the horizontal direction from the lower end of the boss portion 151, and It has a cylindrical portion 153 that extends upward from the upper surface of the peripheral portion of the flange portion 152, and an annular protrusion 155 that protrudes outward in the horizontal direction from the upper portion of the cylindrical portion 153. A short-axis columnar bulging portion 154 is formed. The lower piece 110 has a boss portion 111 having a center hole 111a and a flange portion 112 extending outward in the horizontal direction, and a short-axis columnar bulging portion 113 is formed at the center of the upper surface of the flange portion 112. The outer diameter of the bulging portion 113 is the same as that of the bulging portion 154 of the support piece 150. The support piece 150 and the lower piece 110 are made of a metal having a predetermined strength such as aluminum.

  In the nylon cord storage case 120, the center hole 121a is simultaneously fitted to the bulging portion 154 of the support piece 150 and the bulging portion 113 of the lower piece 110, and the lower surface of the flange portion 152 of the support piece 150 and the flange of the lower piece 110 are The inward flange portion 121 sandwiched between the upper surface of the portion 112 and an annular housing portion 122 connected to the outer periphery of the inward flange portion 121 are formed, for example, by resin integral molding. The housing portion 122 includes a cylindrical inner peripheral wall 122a, a donut disk-shaped bottom wall 122b extending horizontally from the lower end of the inner peripheral wall 122a, and a cylindrical outer peripheral wall 122c extending vertically upward from the outer peripheral portion of the bottom wall 122b. Is formed in a groove shape that is open at the top.

  The cover body 140 is disposed so as to close the upper open portion of the housing portion 122 of the nylon cord housing case 120. In the present embodiment, the cover body 140 hangs down from the donut disk-shaped top plate portion 141 and the inner peripheral edge of the top plate portion 141, and is externally fitted to the inner peripheral wall 122a of the housing portion 122 so as to be vertically slidable. A cylindrical body part 143, a peripheral wall part 142 that hangs down from the outer peripheral edge of the top plate part 141 and is slidably mounted on the outer peripheral wall 122c of the housing part 122 so as to be slidable up and down, And is formed by resin integral molding, for example. In the cover body 140, the cylindrical body 143 is fitted on the inner peripheral wall 122 a of the housing part 122, the annular protrusion 144 is fitted on the outer surface of the cylindrical part 153 of the support piece 150, and the peripheral wall 142 is While being fitted on the outer peripheral wall 122c of the housing portion 122, it can move up and down with a predetermined stroke and can rotate around the rotary blade mounting shaft 14. Further, a compression coil spring 156 is interposed between the lower surface of the annular protrusion 155 of the support piece 150 and the upper surface of the annular protrusion 144 of the cover body 140, so that the cover body 140 is always downward It is energized towards.

  A plurality of rectangular engaging protrusions 145 projecting downward are formed at the lower end of the cylindrical body portion 143 of the cover body 140 by forming a plurality of rectangular recessed portions 145a at equal pitches in the circumferential direction. . On the other hand, on the upper surface of the inner peripheral portion of the bottom wall 122b of the housing portion 122, a plurality of rectangular engaging protrusions 131 that can be fitted into the recessed portion 145a are formed. The radial width of the housing portion 122 of the engagement protrusion 131 corresponds to the thickness of the cylindrical body portion 143 of the cover body 140. The engagement protrusion 131 of the housing portion 122 is fitted into the recess portion 145a when the circumferential position of the recess portion 145a between the adjacent engagement protrusion portions 145 of the cover body 140 is matched, and thus the housing portion 122 is engaged. The engagement protrusion 131 and the engagement protrusion 145 of the cover body 140 are in a mutually engaged state, and relative rotation of the cover body 140 with respect to the housing portion 122 or the nylon cord housing case 120 is prevented. Further, the engagement state between the engagement protrusion 131 of the housing portion 122 and the engagement protrusion 145 of the cover body 140 is such that the cover body 140 is constantly urged downward by the compression coil spring 156. Maintained stably.

  Further, when the cover body 140 is pulled upward against the urging force of the compression coil spring 156, the engagement state between the engagement protrusion 145 of the cover body 140 and the engagement protrusion 131 of the housing portion 122 is released, and the cover The body 140 can be rotated relative to the housing portion 122 or the nylon cord housing case 120. For the convenience of operation with respect to the cover body 140, in the embodiment shown in the figure, a knurl 146 is formed in a bulging shape on the upper outer peripheral surface of the peripheral wall portion 142 of the cover body 140.

  As shown in FIGS. 2, 3, and 5, a pair of holes 147 adjacent to each other in the circumferential direction are formed at appropriate positions on the top plate part 141 of the cover body 140. Nylon cords 4 substantially passing through the vicinity of the longitudinal center of the nylon cord 4 are accommodated in the housing portion 122 of the nylon cord accommodation case 120. In the present embodiment, the cylindrical body 143 of the cover body 140 is fitted on the inner peripheral wall 122a of the housing part 122 as described above, and the nylon cord 4 is wound around the outer periphery of the cylindrical body 143 of the cover body 140. It is accommodated in the housing part 122 in the removed state. The leading end sides of the two nylon cords 4 are led out to the outside from the lead-out holes 123 opened at two locations so as to face the nylon cord housing case 120 in the diametrical direction, and the leading end side of the portion thus led out is It functions as the nylon cord cutting blade 4a. In the present embodiment, the lead-out hole 123 is formed in an aluminum hole that is excellent in wear resistance in a through hole 124 that is formed obliquely at the boundary between the outer peripheral wall 122c and the bottom wall 122b of the nylon cord housing case 120. A cylindrical collar 125 is mounted. That is, the lead-out hole 123 is inclined so that the outer end thereof is lower than the inner end, whereby the nylon cord cutting blade 4a is described later from a fixed position of the nylon cord housing case 120. The guide member 200 is led out to the outside while being closer to the upper surface.

  As understood from FIGS. 2, 3, and 4, when the cover body 140 is rotated relative to the nylon cord housing case 120, the cover body 140 is wound and held in the cylindrical body 143 integrated with the cover body 140. The nylon cord 4 is integrated with the cover body 140 and rotated relative to the nylon cord housing case 120. That is, according to the rotation operation of the cover body 140, the length of the nylon cord cutting blade 4a led out from the lead-out hole 123 can be adjusted. Here, when the operation cover body 140 is rotated relative to the nylon cord storage case 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 direction, the extension length of the nylon cord cutting blade 4a can be extended.

  The guide member 200 includes a central cylindrical portion 211 and a disc portion 220 extending from the lower end of the central cylindrical portion 211, and is preferably integrally formed of resin. In this embodiment, the disc part 220 is a horizontal flat plate shape, and the several recessed part 240 is formed in the outer peripheral part. In the present embodiment, as shown in FIG. 5, the plurality of recesses 240 are formed at equal pitches in the circumferential direction so as to be recessed from the circular outer peripheral edge of the disc part 220. The formation pitch of the recesses 240 can be, for example, in the range of 20-30 mm, the circumferential width w of the recesses 240 can be in the range of 15-25 mm, and the depth d of the recesses 240 can be in the range of 5-13 mm. However, it is not limited to this. As clearly shown in FIG. 5, it is important that the bottom 240c of the recess 240 is smoothly curved.

  As shown in FIGS. 2, 3, and 5, the outer periphery of the disc part 220 (the outer peripheral 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 guide member 200.

  The attachment of the rotary blade A1 to the rotary blade attachment shaft 14 is performed as follows, for example. First, the support piece 150, the lower piece 110, the nylon cord accommodation case 120, and the cover body 140 are combined, and the holding member 100 in a state where the nylon cord 4 is accommodated in the nylon cord accommodation case 120 as described above is attached to the support piece 150. The spline hole 151 a of the boss portion 151 is spline fitted to the rotary blade mounting shaft 14 to be held on the rotary blade 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 boss portion 111 of the lower 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 boss portion 111 of the lower piece 110. Thus, the boss 111 of the lower piece 110 and the inner ring 232 of the bearing 230 are clamped and fixed between the rotary blade mounting shaft 14 or the support piece 150 and the head 15 a of the bolt 15. At the same time, since the inward flange portion 121 of the nylon cord housing case 120 is sandwiched between the flange portion 152 of the support piece 150 and the flange portion 112 of the lower piece 110, the nylon cord housing case 120 is also The rotary blade mounting shaft 14, the support piece 150 and the lower piece 110 are integrated. As shown in FIGS. 2 and 3, the bearing 230 and the head portion 15 a of the bolt 15 are assembled in the form of being accommodated in the central cylindrical portion 211 of the guide member 200, so that the flat circle of the guide member 200 is formed. There are no protrusions on the lower surface side of the plate portion 220.

  For example, a nylon cord cutting blade 4a having a diameter of about 3 mm is used. In the assembled state described above, the nylon cord cutting blade 4a is led out from a lead-out hole 123 formed facing obliquely downward at the boundary between the outer peripheral wall 122c and the bottom wall 122b of the nylon cord housing case 120. Therefore, in a state where the rotary blade A1 is rotated at a high speed, the nylon cord cutting blade 4a rotating with the rotation of the holding member 100 can be brought close to the upper surface of the guide member 200. For example, the nylon cord cutting blade 4a and the guide member The gap between the upper surface of 200 is, for example, 2 to 5 mm, more preferably about 2 to 3 mm, and can be reduced to a minimum of about 2 mm. In this state, the nylon cord cutting blade 4a is adjusted so that the tip position thereof coincides with the outer edge of the guide member 200 or slightly extends.

  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 more than the upper surface of the guide member 200 as the rotary blade attachment shaft 14 rotates. 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 by receiving the rotational driving force of the small engine 11 of the mower B even during the rotation of the holding member 100 or the nylon cord cutting blade 4a, and does not rotate. This means that it is possible to maintain a non-rotating state.

  The dimensions of each part of the rotary blade A1 are set such that 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 500 mm, for example, but these dimensions are not limited.

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

  When mowing using the mower B, for example, if the throttle opening of the engine 11 is increased by operating a throttle lever or the like, the rotary blade A1 is held by the rotational output of the small 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 rotation speed of the holding member 100 or the nylon cord cutting blade 4a reaches, for example, 5,000 to 6,300 rpm. If the outer diameter of the rotary blade A1 (the outer diameter of the guide member 200) is 300 mm, for example, the peripheral speed of the tip of the nylon cord cutting blade 4a will easily reach 350 km / h. When the rotary blade A1 is moved along the ground, a relatively soft and thin object such as weed turns at a high speed as described above at the moment when it enters the recess 240 formed on the outer periphery of the guide member 200. The nylon cord cutting blade 4a receives a strong collision from the lateral direction and is cut without difficulty by the impact. The nylon cord cutting blade 4a has a diameter of about 3 mm at most and is lightweight, but the peripheral speed of the tip is extremely high as described above, so that it is necessary to cut soft weeds and other stems. It has enough kinetic energy.

  More specifically, in the present embodiment, a plurality of recesses 240 are formed on the outer periphery of the guide member 200. Therefore, when the rotary blade A1 is moved along the ground, weeds and the like are as shown in FIG. In addition, it is subjected to a cutting action by the nylon cord cutting blade 4a that rotates at a high speed in a state where the stem portion P is captured in the recess 240. Thereby, a shocking shearing force can be effectively applied to weeds or the like to cut it. In addition, in this embodiment, the gap between the nylon cord cutting blade 4a that rotates at high speed and the upper surface of the guide member 200 is as small as 2 to 5 mm, and more preferably 2 to 3 mm. The inner surface 240a on the front side in the rotational direction and the Nanlon cord cutting blade 4a that rotates while extending in the radial direction of the rotary blade A1 act as if the blade of a reed acts as an instantaneous shearing force on weeds and the like. Can be cut. Such a cutting action is also effective for harvesting climbing weeds such as morning glory that could not be easily cut by a conventional rotary blade.

  In addition, in the present embodiment, the bottom 240c of the recess 240 of the guide member 200 is smoothly curved. Therefore, when the rotary blade A1 moves along the ground, a stump such as an upright weed is formed in the recess 240. It is hard to get caught in. Further, since the guide member 200 has a flat plate shape and no protrusions on the lower surface, the rotary blade A1 can be moved so as to slide along the ground.

  For this reason, according to the rotary blade A1 according to the present embodiment, the weight of the rotary blade A1 can be applied to the ground, and the tip in that direction can be moved in any direction along the ground. Therefore, weeds and the like can be cut and there is little fatigue and work efficiency is remarkably increased.

  As described above, in the present embodiment, it is desirable to use the nylon cord cutting blade 4a so that the tip of the nylon cord cutting blade 4a coincides with the outer peripheral edge of the guide member 200. In this case, the holding member 100 or the nylon cord cutting Even when the blade 4a is rotating at high speed, the tip of the nylon cord cutting blade 4a does not directly contact the ground. Therefore, the nylon cord cutting blade 4a that rotates at high speed does not jump off pebbles and sand on the ground, and is safe, and the tip of the nylon cord cutting blade 4a does not wear unnecessarily. Even if the tip of the nylon cord cutting blade 4a extends from the outer peripheral edge of the guide member 200 and comes into contact with a hard object, the impact is absorbed by the nylon cord cutting blade 4a being bent and deformed. The rotary blade A1 is not damaged by an impact, and the rotation speed of the holding member 100 or the nylon cord cutting blade 4a is not reduced. Further, if the nylon cord cutting blade 4a is worn until the tip position coincides with the outer peripheral edge of the guide member 200, further wear is suppressed, and the tip of the nylon cord cutting blade 4a matches the outer peripheral edge of the guide member 200. Appropriate status automatically appears.

  In the use state in which the holding member 100 or the nylon cord cutting blade 4a is rotated at a high speed, the cover body 140 of the holding member 100 is always urged downward by the compression coil spring 156, and as shown in FIG. The state in the down position is maintained. At this time, the engagement protrusion 145 of the cover body 140 and the engagement protrusion 131 of the housing part 122 are engaged, and relative rotation of the cover body 140 with respect to the nylon cord housing case 120 is prevented. Therefore, even if the nylon cord cutting blade 4a is rotated at a high speed, the extension length from the lead-out hole 123 is maintained substantially constant.

  As the nylon cord cutting blade 4a continues to be used, wear, breakage or the like occurs at the tip, and the extension length from the lead-out hole 123 gradually decreases. In such a case, when the small engine 11 is stopped and the rotary blade A1 is stationary and the cover body 140 is pulled up, the engagement state between the engagement protrusions 145 and 131 is as shown in FIG. The cover body 140 and the nylon cord storage case 120 are in a state where relative rotation is allowed. Here, when the cover body 140 is rotated relative to the nylon cord housing case 120 in the nylon cord feeding direction, the extension length of the nylon cord cutting blade 4a can be extended. At this time, the cover body 140 is rotated by an amount corresponding to the formation pitch of the engagement protrusions 145 and 131 and the engagement protrusions 145 and 131 are mutually engaged again, so that the formation pitch of the engagement protrusions 145 and 131 is substantially increased. The nylon cord cutting blade 4a can be extended by a length corresponding to (for example, by 10 to 15 mm).

  In the present embodiment, a simple operation of pulling up and moving the cover body 140 up allows the operation cover body 140 to be allowed to rotate relative to the nylon cord storage case 120, and the nylon cord cutting blade 4a extends. The length can be adjusted.

  In the rotary blade A1, the portion rotated by the output of the small engine 11 of the mower 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 4a can be as low as 150 to 200 g. Therefore, the burden on the small engine 11 is small, the peripheral speed of the nylon cord cutting blade 4a can be further increased, and the high-speed rotation state can be maintained.

  The diameter of the guide member 200 can be variously changed. For example, the diameter of the guide member 200 may be about 300 to 500 mm. When the diameter of the guide member 200 is 500 mm and the rotation speed of the holding member 100 is 6300 rpm, the peripheral speed of the guide member 200, that is, the speed of the tip of the nylon cord cutting blade 4a reaches about 600 km / h. Become. As described above, the portion rotated by the rotary blade A1 is only the holding member 100 or the nylon cord cutting blade 4a, and the guide member 200 having a relatively large diameter is not rotated. The tip speed of the cutting blade 4a can be achieved. 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 also high, mowing work in a wider area can be performed very efficiently.

  In addition, although the rotary blade A1 is configured using two nylon cords 4, the number of nylon cords 4 may be increased. For example, the four nylon cords 4 may be configured to be led out to the outside from the lead-out holes 123 provided evenly allocated to four locations on the outer peripheral wall 122c of the nylon cord housing case 120. 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 accurately cut even if the entire rotary blade A1 is moved relatively quickly, and as a result, mowing work Can be performed more efficiently.

  FIG. 6 shows another example of a rotary blade for a mower according to the present invention. In FIG. 6, the same or similar elements as those in the embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the rotary blade A2 shown in FIG. 6, in the holding member 100, the lead-out hole 123 for leading the nylon cord 4 from the nylon cord housing case 120 is not inclined but extends in the horizontal direction. Unlike the rotary blade A1 described above, the horizontal outer peripheral portion 220c is displaced upward with respect to the flat horizontal main portion 220a, and the remaining configuration is the same. In the following, the configuration of the rotary blade A2 that is different from the rotary blade A1 will be mainly described.

  Also in the rotary blade A2, lead-out holes 123 are formed at two locations facing the diameter direction of the housing portion 122 of the nylon cord housing case 120. In the present embodiment, the lead-out hole 123 is formed by mounting an aluminum cylindrical collar 125 excellent in wear resistance on a horizontal through hole 124 provided in the outer peripheral wall 122c.

  The guide member 200 of the rotary blade A2 includes a center tube portion 211 and a disc portion 220 extending from the lower end of the center tube portion 211, and is preferably integrally formed of resin. In this embodiment, the disc part 220 has a horizontal main part 220a, an upper inclined part 220b connected to the outer periphery of the horizontal main part 220a, and a horizontal outer peripheral part 220c connected to the outer periphery of the upper inclined part 220b. Thus, the horizontal outer peripheral portion 220c is displaced upward by a predetermined amount with respect to the flat horizontal main portion (general portion) 220a. The horizontal main portion 220a occupies a ratio that sufficiently extends in the radial direction from the outer periphery of the holding member 100. In other words, the radial width of the horizontal outer peripheral portion 220c forms a plurality of concave portions 240 described later. However, it is sufficient that the required strength can be maintained. For example, the radius can be set to 1/3 to 1/20 of the radius of the guide member 200. As will be described later, the displacement amount of the horizontal outer peripheral portion 220c with respect to the horizontal main portion 220a is determined by the nylon cord cutting blade 4a rotating with the rotation of the holding member 100 and the horizontal outer peripheral portion 220c in a state where the rotary blade A2 is rotated at a high speed. For example, the gap between the upper surface and the upper surface is set to 2 to 5 mm, more preferably about 2 to 3 mm.

  A plurality of concave portions 240 are formed in the horizontal outer peripheral portion 220 c of the guide member 200. As a form of this recessed part 240, it can be set as the thing similar to having mentioned above about rotary blade A1, for example.

  The attachment of the rotary blade A2 to the rotary blade attachment shaft 14 can be performed in the same manner as described above for the rotary blade A1.

  The rotary blade A2 also includes a guide member 200 that can be kept in contact with the ground or the like, can reduce the distance between the nylon cord cutting blade 4a and the periphery of the guide member 200 as much as possible, Since a plurality of recesses 240 are formed on the outer periphery, it is common to the rotary blade A1 in that the same efficient mowing work as described above for the rotary blade A1 can be performed.

  In the rotary blade A2, the guide member 200 is not entirely a flat plate, and the horizontal outer peripheral portion 220c having a predetermined radial width is displaced upward with respect to the horizontal main portion 220a. When the guide member 200 is formed by resin molding, the thickness can be further reduced to further reduce the weight.

  Further, also in the rotary blade A2, the horizontal main portion 220a of the guide member 200 is wide and there is no projection on the lower surface thereof, so that the mowing work can be performed by sliding along the ground. In the rotary blade A2, the horizontal outer peripheral portion 220c of the guide member 200 is displaced upward by a predetermined amount, so that weeds and the like are cut from the ground at a predetermined fixed height position, and the appearance of the ground after mowing work is improved. Can be improved.

  For the cutting blade A2, the extension length of the nylon cord cutting blade 4a from the outlet hole 123 can be adjusted in the same manner as described above for the cutting blade A1. Moreover, the diameter dimension of the guide member 200 and the number of the nylon cord cutting blades 4a can be variously set similarly to the example described for the cutting blade A1.

  Of course, the scope of the present invention is not limited to the above-described embodiments, and all modifications within the scope of the claims are all encompassed in the scope of the present invention.

  In the rotary blade A1, by adopting a mechanism that allows the cover body 140 to be moved up and down to select a relative rotation disabled state of the cover body 140 with respect to the housing portion 122 and a relative rotation permissible state, the nylon cord is cut by a simple operation. Although the extension length of the blade 4a can be adjusted, whether or not to employ such a mechanism is a matter of choice.

  Furthermore, in the rotary blade A1 and the rotary blade A2, a plurality of concave portions 240 are provided on the outer periphery of the guide member 200. Whether or not such concave portions 240 are provided is a matter of choice. Even if such a plurality of recesses 240 are not provided, if the clearance between the upper surface of the nylon cord cutting blade 4a and the guide member 200 is 2 to 5 mm, preferably about 2 to 3 mm, the tip of the nylon cord cutting blade 4a is By extending the outer peripheral edge of the guide member 200 by about 10 to 20 mm, a sufficiently efficient cutting action can be expected as compared with the conventional case.

  Furthermore, in the rotary blade A1 and the rotary blade A2, when a plurality of recesses 240 are provided on the outer periphery of the guide member 200, the form of the recesses 240 is not limited, and for example, the form shown in FIG. 7 and FIG. You can also.

  In the form shown in FIG. 7, a plurality of concave portions 240 whose bottom portions are smoothly curved are formed by forming a plurality of convex portions 250 such as saw blades on the outer periphery of the guide member 200. In other words, the slope of the inner surface 240a on the front side in the rotational direction of the nylon cord cutting blade 4a in the recess 240 is steeper than the slope of the inner surface 240b on the rear side in the rotational direction, and the weed stalk captured on the inner surface 240a on the front side in the rotational direction. The stem can be cut by effectively giving P a shearing force by the nylon cord cutting blade 4a that turns at high speed. Since the inclination of the inner surface 240b on the rear side in the rotation direction is gentle, the target weed can be smoothly introduced into the recess 240 and used for the cutting action described above. Moreover, since the bottom part 240c of the recessed part 240 curves smoothly, the cut stump is not caught in the recessed part 240, and the movement along the ground of rotary blade A1, A2 is not inhibited. Also in this case, the width w of the recess 240 can be in the range of, for example, 15 to 25 mm, and the depth d of the recess 240 can be in the range of, for example, 5 to 13 mm, but is not limited thereto. However, the point that the bottom portion 240c of the recess 240 is smoothly curved is the same as in the above embodiment.

  In the embodiment shown in FIG. 8, a concave portion 240 is formed between a plurality of triangular mountain-shaped convex portions 250a, the bottom portion 240c of the concave portion 240 is smoothly curved, and the inner surface of the concave portion 240 is shown in a cross section in FIG. A sharp blade shape is formed by inclining 241.

  If comprised in this way, when the nylon cord cutting blade 4a which rotates at high speed collides with the weeds etc. which were caught by the recessed part 240, a shear force will be made to act on weeds etc. more effectively, and this weeds etc. will be cut | disconnected quickly. Can do. Further, since the inner surface 241 of the recess 240 is inclined, it becomes easier for stubs such as weeds to come out of the recess 240, and the rotary blades A1 and A2 can be smoothly moved along the ground. Also in this case, the width w of the recess 240 can be set to, for example, 15 to 25 mm, and the depth d of the recess 240 can be set to, for example, 5 to 13 mm, but is not limited thereto.

  Furthermore, although illustration is omitted, a plurality of through holes may be formed in the disc portion 220 of the guide member 200. In this way, the guide member 200 can be further reduced in weight.

  Furthermore, the mower used by attaching the rotary blades A1 and A2 of the present invention is not limited to the one having the rotary blade attachment shaft 14 at the tip of the operation tube 12 as shown in FIG. The rotary blades A1 and A2 of the present invention are also applied to a so-called self-propelled mower having a power source such as an engine and a rotary blade mounting shaft that is rotationally driven by the power source. Can be used.

A1, A2 Rotary blade B Mower 4a Cord cutting member (Nylon cord cutting blade)
14 Rotating blade mounting shaft 15 Mounting bolt 15a Head (bolt)
DESCRIPTION OF SYMBOLS 100 Holding member 110 Lower piece 123 Lead-out hole 200 Guide member 220 Disc part 220a Horizontal main part 220c Horizontal outer peripheral part 240 Concave part 240c Bottom part (concave part)

Claims (12)

A holding member that is attached to the rotary blade attachment shaft of the mower and rotated;
A cord-shaped cutting member in which a proximal end side is held by the holding member and a distal end side is led out radially outward from a lead-out hole provided in the holding member;
A guide member that can rotate relative to the holding member at the lower part of the holding member about the rotation axis thereof;
The rotary blade for a mowing machine, wherein the lead-out hole is inclined with respect to the inner end thereof so that the outer end is lower.   The rotary blade for a mower according to claim 1, wherein the guide member has a disc shape. A holding member that is attached to the rotary blade attachment shaft of the mower and rotated;
A cord-shaped cutting member in which a proximal end side is held by the holding member and a distal end side is led out radially outward from a lead-out hole provided in the holding member;
A guide member that can rotate relative to the holding member at the lower part of the holding member about the rotation axis thereof;
The rotary blade for a mowing machine, wherein the guide member has a disk shape having a general part and an outer peripheral part displaced upward with respect to the general part.   The rotary blade for a mower according to claim 3, wherein the general part is a flat plate, and the outer peripheral part is a flat plate displaced upward with respect to the general part.   The rotary blade for a mower according to claim 4, wherein a radial width of the outer peripheral portion is 1/3 to 1/20 of a radius of the guide member. A holding member that is attached to the rotary blade attachment shaft of the mower and rotated;
A cord-shaped cutting member in which the proximal end side is held by the holding member and the distal end side is led out radially outward;
A guide member that can rotate relative to the holding member at the lower part of the holding member about the rotation axis thereof;
The rotary blade for a mower, wherein the guide member has a plurality of recesses formed on an outer periphery thereof.   The rotary blade for a mower according to claim 6, wherein bottoms of the plurality of recesses are smoothly curved.   The rotary blade for a mower according to any one of claims 1 to 7, wherein the guide member is made of resin.   The rotary blade for a mower according to any one of claims 1 to 8, wherein the cord-shaped cutting member is made of nylon. The holding member is connected to the rotary blade attachment shaft and rotates integrally with the rotary blade attachment shaft, and a main body portion that houses the proximal end side of the cord-shaped cutting member in a wound state;
It is positioned higher than the main body, and is combined in such a manner that it can be moved with a predetermined stroke in the axial direction of the rotary blade mounting shaft and can be relatively rotated around the rotary blade mounting shaft. An operation unit having end-side ends connected thereto;
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. The rotary blade for a mower according to any one of claims 1 to 9, further comprising a clutch mechanism that allows relative rotation between the operation portion and the main body portion when the operation portion is moved. 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 mower according to claim 10, 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. A power source and a rotary blade mounting shaft that is rotationally driven by the power of the power source;
The mowing machine according to any one of claims 1 to 11, wherein the rotary blade mounting shaft is attached to the rotary blade mounting shaft.

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