JP2013223433A - Rotating blade for mower and mower using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nylon cord (cord like cutting member) type rotating blade for a mower capable of further enhancing the cutting performance.SOLUTION: A rotating blade A for a mower includes: a holding member 100 attached to a rotating blade attachment shaft 14 of a mower B and rotated; a cord like cutting members 40a and 41a in which a base end side is held by the holding member 100 and a leading end side is extended outward in a radial direction of the holding member 100. The cord like cutting members 40a and 41a are extended from a plurality of positions where a plurality of numbers thereof are different from each other in an axial direction of the rotating blade attachment shaft 14.

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 an instrument 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. Or while controlling the rotation of the rotary blade rotated by this, the operation tube is swung left and right to perform a desired mowing operation.

  Among the rotary blades suitable for this type of portable power mower, as nylon cord type rotary blades, for example, there are those shown in Patent Documents 1 and 2.

  The rotary blade shown in Patent Document 1 is attached to the rotary blade mounting shaft of a mowing machine, rotates together with the rotary blade mounting shaft, and in addition to the holding member that winds and holds the nylon cord (code-like cutting member), this holding A guide member that is rotatably supported around the rotation axis of the member is provided.

  In the rotary blade shown in Patent Document 1, when the extension length of the cord-like cutting member is shortened due to wear or the like, the cord-like cutting member wound around the holding member is extended to extend the length. Since the guide member prevents the cutting target such as weeds from entering the outer periphery of the guide member, the tip portion of the cord-like cutting member that rotates at a high speed is provided. It has the function of being efficiently cut by.

  Moreover, in the rotary blade shown in Patent Document 2, the cord-shaped cutting member is wound around a reel built in the holding member so that the extension length of the cord-shaped cutting member can be adjusted. The base end is connected to an operation member that can be rotated. The operation member can be switched from the state where rotation is not possible to the state where rotation is possible by moving the operation member in one axial direction of the rotary blade mounting shaft against the biasing force of the elastic member. When the extension length of the cord-shaped cutting member is shortened, the operating member is rotated in a predetermined direction while the operating member is moved in one axial direction and maintained in a rotatable operation state. Thereby, the cord-like cutting member is drawn out, and the extension length of the cord-like cutting member can be extended.

  However, since each of the rotary blades shown in Patent Documents 1 and 2 is configured such that one cord-like cutting member extends from each place in the circumferential direction, the tip of the cord-like cutting member The cutting ability is naturally limited. Therefore, there is a disadvantage that weeds having thick stems larger than a predetermined size, weeds that have become dry and hard cannot be easily cut.

  Moreover, in the rotary blade shown in Patent Document 2, the length adjustment of the cord-shaped cutting member is performed by moving the operating member in the axial direction so that the operating member can be rotated, and in this state, the operating member is rotated in a predetermined direction. There is a need. Here, if the rotation direction of the operation member is wrong, the cord-like cutting member is wound up by the holding member, and the extension length of the cord-like cutting member is shortened. Therefore, the rotary blade of Patent Document 2 has room for improvement in the operability of the mechanism that can adjust the extension length of the cord-shaped cutting member.

International Publication WO 2007/023758 International Publication WO2010 / 082347

  The present invention has been conceived under the circumstances described above, and it is a main object of the present invention to further improve the cutting ability in a nylon cord (cord cutting member) type rotary blade for mowing machines.

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

  The rotary blade for 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 mowing machine and is rotated, a proximal end side is held by the holding member, and a distal end side is the holding member. A rotary blade for a mower provided with a cord-like cutting member extended outward in the radial direction, the cord-like cutting members from a plurality of positions different from each other in the axial direction of the mounting shaft It is characterized by being extended.

  In a preferred embodiment, the holding member has a plurality of lead-out holes whose positions in the axial direction are different from each other, and is connected to the mounting shaft and rotates integrally with the mounting shaft, and the main body portion A plurality of operation portions that are combined with each other so as to be movable in a predetermined stroke in the axial direction of the mounting shaft and relatively rotatable around the mounting shaft, and each holding the proximal end side of the cord-shaped cutting member; A plurality of elastic members each urging the operation portion in one axial direction, and the operation portion and the main body portion when the operation portions are in a predetermined position in the stroke by the elastic force of the elastic members. A plurality of clamps that prevent relative rotation between the operation portion and the main body when the operation portions are moved from the predetermined position against the elasticity of the elastic member. With a pitch mechanism, and the respective cord-shaped cutting member, the tip end is brought derived from any of the plurality of lead-out hole.

  In a preferred embodiment, the plurality of cord-like cutting members include first and second cord-like cutting members, and the plurality of operation portions hold a first end side of the first cord-like cutting member. An operation unit; and a second operation unit that holds a proximal end side of the second cord-shaped cutting member. The plurality of elastic members include a first elastic member that urges the first operation unit, and the second A plurality of clutch mechanisms including a first clutch mechanism acting between the first operation part and the main body part; a second operation part; and the main body part. A plurality of lead-out holes located above the first lead-out hole and the first lead-out hole, wherein the plurality of lead-out holes are led out from the distal end side of the first cord-shaped cutting member, A second outlet hole for leading the distal end side of the second cord-shaped cutting member; No.

  In a preferred embodiment, the holding member has a flange portion having a circular outer periphery with a radius larger than the distance from the rotation axis to the farthest one of the first and second outlet holes. The first cord-like cutting member led out from the first lead-out hole is extended below the flange portion, and the second cord-like cutting member led out from the second lead-out hole is It is made to extend above the flange portion.

  In a preferred embodiment, an additional flange portion having a circular outer periphery having a radius larger than the distance from the rotation axis of the holding member to the first lead-out hole is provided, and the first lead out from the first lead-out hole is provided. The cord-shaped cutting member is extended above the additional flange portion.

  In a preferred embodiment, the outer diameter dimension of the additional flange portion is smaller than the outer diameter dimension of the flange portion.

  In a preferred embodiment, the additional flange portion is rotatable relative to the holding member about the rotation axis.

  In a preferred embodiment, the second lead-out hole is located at a position different from the first lead-out hole in the circumferential direction around the rotation axis of the holding member.

  In a preferred embodiment, the second lead-out hole is at the same position as the first lead-out hole in the circumferential direction around the rotation axis of the holding member.

  In a preferred embodiment, the first and second elastic members constantly urge the first and second operation portions upward, respectively, and the first clutch mechanism is A plurality of first engaging portions arranged annularly around the mounting shaft; and the first operating portion, arranged in an annular shape around the mounting shaft, projecting upward and engaging with the plurality of first engaging portions. A plurality of second engaging portions that can be combined, and the second clutch mechanism includes a plurality of third engaging portions that are annularly arranged around the attachment shaft in the main body portion, and the second operation portion. And a plurality of fourth engaging portions that are annularly arranged around the mounting shaft and project upward and engage with the plurality of third engaging portions.

  The mower provided by the second 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, and the rotary blade mounting shaft includes the first of the present invention. The rotary blade for mowers which concerns on the side surface is attached.

  Other features and advantages of the present invention will become more apparent from the description of embodiments described below with reference to the drawings.

It is a schematic perspective view which shows one Embodiment of the rotary blade for mowing machines which concerns on this invention, and the mowing machine using the same. It is a longitudinal cross-sectional view of the rotary blade for mowing machines shown in FIG. It is a top view of a main-body part (nylon cord storage case). It is a principal part longitudinal cross-sectional view in alignment with the circumferential direction for description of a 1st clutch mechanism. It is a longitudinal cross-sectional view for effect | action description of the rotary blade for mowing machines shown in FIG. FIG. 5 is a view similar to FIG. 4 for explaining the operation of the first clutch mechanism. It is a principal part longitudinal cross-sectional view in alignment with the circumferential direction for description of a 2nd clutch mechanism. It is a longitudinal cross-sectional view for effect | action description of the rotary blade for mowing machines shown in FIG. FIG. 8 is a view similar to FIG. 7 for explaining the operation of the second clutch mechanism.

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

  1 to 9 show an embodiment of a rotary blade A for a mower according to the present invention and a mower B using the same. As clearly shown in FIGS. 1 and 2, in the mower B, a small engine (not shown) as a drive source is connected to the proximal end side of the operation tube 12, and the rotation output thereof is operated. It is configured to be transmitted to the distal end portion of the operation tube 12 via a transmission shaft 13 inserted in the tube 12. As the small engine, for example, an engine with a displacement of about 25 cc is used in consideration of the portability of the operator. A small engine 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. 2, 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 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 rotating blade holder 17 made of metal is splined to the rotating blade mounting shaft 14. On the lower surface of the rotary blade holder 17, a short-axis columnar bulging portion 17a is formed.

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

  As shown in FIGS. 1 and 2, the rotary blade A is attached to the rotary blade attachment shaft 14 and rotated, and nylon cord cutting blades 40a and 41a as an example of a cord-like cutting member are provided. A holding member 100 to be held, and a grounding member 200 supported below the holding member 100 so as to be relatively rotatable with respect to the holding member 100 about its rotation axis (the same axis as the rotary blade mounting shaft 14). .

  In the present embodiment, the holding member 100 includes a main body portion 100A and first and second operation portions 100B and 100C. The main body 100 </ b> A also includes a support piece 110 and a nylon cord storage case 120.

  The support piece 110 includes a boss portion 111 having a center hole 111a that can be fitted into the bulging portion 17a of the rotary blade retainer 17, and a flange portion 112 that extends radially outward from the boss portion 111. Formed by. A plurality of first engaging convex portions 151 constituting a first clutch mechanism 150 to be described later are formed on the lower surface of the flange portion 112, which will be described later.

  The nylon cord storage case 120 includes a thrust collar 121 having a center hole 121a, a boss portion 122 connected to the outer periphery of the thrust collar 121, and annular first and second housing portions 123 connected to the outer periphery of the boss portion 122. , 124. The thrust collar 121 is made of, for example, metal, and the boss portion 122 and the first and second housing portions 123 and 124 are made of, for example, resin. The thrust collar 121 has a groove on the outer peripheral portion, and the thrust collar 121 and the boss portion 122 are connected by press-fitting the thrust collar 121 so that the groove fits into the inner peripheral portion of the boss portion 122. . The boss portion 122 has the same outer diameter as the inner diameter of the boss portion 111 of the support piece 110, and a circular bulge portion 122 a that fits into the center hole 111 a of the support piece 110 is formed on the upper surface.

  The first housing portion 123 includes a cylindrical inner peripheral wall 123a, a donut disk-shaped bottom wall 123b extending horizontally from the lower end of the inner peripheral wall 123a, and a cylindrical intermediate portion extending vertically upward from the outer peripheral portion of the bottom wall 123b. It is surrounded by a wall 123c and has a groove shape that opens upward.

  The second housing part 124 is located on the outer peripheral side of the first housing part 123. The second housing portion 124 includes an intermediate wall 123c, a donut disk-shaped bottom wall 124d extending horizontally from the intermediate portion in the vertical direction of the intermediate wall 123c, and a cylindrical outer periphery extending vertically upward from the outer peripheral portion of the bottom wall 124d. It is surrounded by a wall 124e and has a groove shape that opens upward. On the upper outer surface of the intermediate wall 123c, a plurality of third engagement convex portions 161 (see FIG. 3) constituting a second clutch mechanism 160 described later are formed. A convex portion 124f that protrudes upward is formed at an appropriate position on the bottom wall 124d.

  A cylindrical cord winding portion 170 for winding and holding a nylon cord 40 to be described later is attached to the first housing portion 123. The cord winding portion 170 has a small diameter cylindrical portion 170a whose lower end is in contact with the bottom wall 123b of the first housing portion 123, and a large diameter cylindrical portion 170b connected to the upper side of the small diameter cylindrical portion 170a. The cord winding portion 170 has a slight gap between the inner peripheral surface of the small diameter cylindrical portion 170a and the outer peripheral surface of the inner peripheral wall 123a of the first housing portion 123 when the cord winding portion 170 is attached. The housing case 120 is rotatable about its rotational axis (same axis as the rotary blade mounting shaft 14). A predetermined annular space is formed between the inner peripheral surface of the large diameter cylindrical portion 170b and the outer peripheral surface of the inner peripheral wall 123a.

  The first operation portion 100B is positioned so as to close an upper open portion of the first housing portion 123 of the nylon cord housing case 120, and is made of resin having a donut disk shape as a whole. The first operation portion 100B is fitted to the outer periphery of the boss portion 111 of the support piece 110 or the outer periphery of the boss portion 122 of the nylon cord housing case 120 so as to be rotatable and slidable in the vertical direction. A stepped portion 131 is formed on the upper surface on the inner peripheral side of the first operating portion 100B, and the first clutch mechanism 150 is formed on the upper surface of the stepped portion 131 in cooperation with the plurality of first engaging convex portions 151 described above. A plurality of second engaging projections 152 are formed. The outer peripheral portion of the first operation portion 100B is a thin dust-proof wall 132 that wraps around from the upper side of the intermediate wall 123c of the nylon cord housing case 120, leaving a margin for the first operation portion 100B to move downward. Further, a protrusion 133 spaced apart in the circumferential direction is formed on the upper portion of the dust barrier wall 132, and the protrusion 133 prevents slipping when the first operation portion 100B is rotated.

  In the annular space formed between the inner peripheral surface of the large-diameter cylindrical portion 170b of the cord winding portion 170 and the outer peripheral surface of the inner peripheral wall 123a of the first housing portion 123, the upper end is an appropriate portion of the first operation portion 100B. Further, the compression coil spring 180 is incorporated so that the lower end thereof is in elastic contact with the upper end of the small diameter cylindrical portion 170a of the cord winding portion 170. Accordingly, the first operation unit 100B is always urged upward.

  As described above, the first clutch mechanism 150 is formed by the plurality of first engagement convex portions 151 provided on the support piece 110 and the plurality of second engagement convex portions 152 provided on the first operation portion 100B. The The first engagement protrusions 151 are arranged in an annular shape with a space in which the second engagement protrusions 152 can be fitted, and the second engagement protrusions 152 are formed as the first engagement protrusions 151. They are arranged in an annular region that overlaps the region in the vertical direction. Further, the side surfaces 151a and 152a of the first engaging portion 151 and the second engaging convex portion 152 that are in contact with each other are inclined as shown in FIG. The direction of the inclination of the side surfaces 151a and 152a is the direction deviating from the rotational drive direction indicated by N in FIG. Further, the top surface 151b of the first engaging convex portion 151 and the top surface 152b of the second engaging convex portion 152 are horizontal flat surfaces, and as shown in FIG. 6, the two top surfaces 151b and 152b are connected to each other. In the abutting state, the first operating portion 100B can slide relative to the support piece 110 by sliding in a resilient contact state with each other.

  As shown in FIGS. 2 and 3, a nylon cord lead-out hole (first lead-out hole 125) is formed at two locations facing the diameter direction of the first housing part 123 in the intermediate wall 123 c of the first housing part 123. Is formed. In the present embodiment, a collar 126 made of a hard material having excellent wear resistance is fitted into a hole 123g formed in the intermediate wall 123c.

  As shown in FIG. 2, a pair of circumferentially adjacent holes 135 are formed at appropriate positions of the first operation portion 100B, and the nylon cord 40 is passed through these holes 135 in the vicinity of the center thereof. The nylon cord 40 that is substantially two is wound around the cord winding portion 170, and is accommodated in the first housing portion 123 of the nylon cord accommodation case 120. The leading ends of the two nylon cords 40 are led out to the outside from the first lead-out holes 125 opened in two locations facing the diametrical direction of the nylon cord housing case 120, respectively, It will function as the nylon cord cutting blade 40a.

  The second operation portion 100C is positioned so as to close the upper open portion of the second housing portion 124 of the nylon cord housing case 120, and is made of resin having a donut disk shape as a whole. The second operation unit 100C is fitted on the outer periphery of the dust-proof wall 132 of the first operation unit 100B so as to be rotatable and slidable in the vertical direction. A cylindrical inner wall portion 141 is formed on the inner peripheral side of the second operation portion 100C, and the lower inner peripheral surface of the inner wall portion 141 cooperates with the plurality of third engagement convex portions 161 described above. A plurality of fourth engagement convex portions 162 constituting the second clutch mechanism 160 are formed. The outer peripheral portion of the second operation portion 100C is a thin dust-proof wall 142 that wraps around from the upper side of the outer peripheral wall 124e of the nylon cord housing case 120, leaving a margin for the second operation portion 100C to move downward.

  A cylindrical cord winding portion 171 for winding and holding the nylon cord 41 is attached to the second housing portion 124 of the nylon cord housing case 120 described above. When the cord winding portion 171 is attached, the inner peripheral surface is between the outer peripheral surface of the inner wall portion 141 of the second operation portion 100C and the outer peripheral surface is between the convex portion 124f of the second housing portion 124. Each has a slight gap, so that it can rotate with respect to the nylon cord housing case 120 around its rotational axis (same axis as the rotary blade mounting shaft 14).

  In the annular space formed between the inner peripheral surface of the cord winding portion 171 and the outer peripheral surface of the intermediate wall 123c of the nylon cord storage case 120, the upper end is an appropriate portion of the second operation portion 100C and the lower end is the second. A compression coil spring 181 is incorporated so as to elastically contact the bottom wall 124d of the housing portion 124. Thus, the second operation unit 100C is always urged upward.

  As described above, the second clutch mechanism 160 includes the plurality of third engagement protrusions 161 provided on the intermediate wall 123c of the nylon cord housing case 120 and the plurality of fourth engagement protrusions provided on the second operation portion 100C. Part 162. The third engagement protrusions 161 are arranged in an annular shape with a space in which the fourth engagement protrusions 162 can be fitted, and the fourth engagement protrusions 162 are formed as the third engagement protrusions 161. They are arranged in an annular region that overlaps the region in the vertical direction. Further, the side surfaces 161a and 162a of the third engaging convex portion 161 and the fourth engaging convex portion 162 that are in contact with each other are inclined as shown in FIG. The direction of inclination of the side surfaces 161a and 162a is a direction that shifts in the rotational drive direction indicated by N in FIG. Further, the top surface 161b of the third engaging convex portion 161 and the top surface 162b of the fourth engaging convex portion 162 are horizontal flat surfaces, and as shown in FIG. 9, the two top surfaces 161b and 162b are connected to each other. In the abutted state, the second operating portion 100C can slide relative to the nylon cord housing case 120 by sliding in a resilient contact state with each other.

  As shown in FIGS. 2 and 3, nylon cord lead-out holes (second lead-out holes 127) are equally spaced in the circumferential direction of the second housing part 124 in the outer peripheral wall 124 e of the second housing part 124. As shown in FIG. A pair of second lead-out holes 127 formed at two places facing each other in the diameter direction among the second lead-out holes 127 provided at these four places are provided at two places in the first housing portion 123 in the circumferential direction. The first outlet hole 125 is located at the same position. Further, another pair of second lead-out holes 127 different from the pair of second lead-out holes 127 are circular in relation to the first lead-out holes 125 provided at two locations in the first housing portion 123. It is in a different position in the circumferential direction. In this embodiment, the collar 128 made of a hard material having excellent wear resistance is fitted into the hole 124h formed in the outer peripheral wall 124e.

  As shown in FIG. 2, a pair of circumferentially adjacent holes 145 are formed at appropriate positions of the second operation portion 100C, and the nylon cord 41 is passed through these holes 145 in the vicinity of the center thereof. The nylon cord 41 that has become substantially two is wound around the cord winding portion 171, and is accommodated in the second housing portion 124 of the nylon cord accommodation case 120. The leading end sides of the two nylon cords 41 are led out to the outside from two second lead-out holes 127 opposed to the nylon cord housing case 120 in the diametrical direction. It will function as the cord cutting blade 41a. In the present embodiment, the distal end side of the nylon cord 41 is led out through two second lead-out holes 127 located at the same position in the circumferential direction as the first lead-out holes 125 provided in two places of the first housing portion 123. The Here, the nylon cord cutting blade 41a led out from the second lead-out hole 127 is positioned higher than the nylon cord cutting blade 40a led out from the first lead-out hole 125, and these nylon cord cutting blades 40a and 41a are Overlapping in the vertical direction.

  As shown in FIGS. 1 and 2, in the present embodiment, the nylon cord housing case 120 is provided with a flange portion 190. The flange portion 190 extends in the horizontal direction from the lower surface of the bottom wall 124d and has a constant outer diameter. The flange portion 190 is made of, for example, resin, and is formed separately from the nylon cord housing case 120 and integrated with the nylon cord housing case 120 by screws 191. The flange portion 190 extends radially outward from the second outlet hole 127. The outer diameter of the flange portion 190 is, for example, 200 to 400 mm, preferably 250 to 350 mm, but is not limited thereto.

  The nylon cord cutting blade 40 a led out from the first lead-out hole 125 extends below the flange portion 190, and the nylon cord cutting blade 41 a led out from the second lead-out hole 127 extends above the flange portion 190. I'm out. The extension lengths of the nylon cord cutting blades 40a and 41a are adjusted so that the respective tips protrude from the outer peripheral edge of the flange portion 190 by about 30 to 60 mm in a state where the extension length is extended in the radial direction of the holding member 100. .

  The grounding member 200 includes a center tube portion 211 and a flange portion 220 extending from the lower end of the center tube portion 211, and the flange portion 220 corresponds to the outer periphery of the first housing 123 below the first housing portion 123. It extends horizontally to the vicinity, and the outer peripheral side is displaced upward. In this embodiment, the inner peripheral part of the center cylinder part 211 and the flange part 220 is formed of metal, and the remaining part of the flange part 220 is formed of resin. The integration of the metal portion and the resin portion can be performed by an insert molding method. Two bearings 230 stacked in the axial direction are held on the inner surface of the central cylindrical portion 211 of the grounding member 200 by press-fitting the outer ring 231. The grounding member 200 rotates the bolt 15 passing through the center hole 121a of the bearing 230 and the thrust collar 121 while the inner ring 232 of the upper bearing 230 is in contact with the lower surface of the thrust collar 121 of the nylon cord housing case 120. By screwing into the screw hole 14 a of the blade mounting shaft 14, the bolt 15 is supported so as to be relatively rotatable about its axis (axis of the rotary blade mounting shaft 14). By tightening the bolt 15, the support piece 110 and the nylon cord housing case 120 are integrated with the rotary blade mounting shaft 14.

  The flange portion 220 of the ground member 200 extends outward in the radial direction from the first and second lead-out holes 125 and 127. The outer diameter dimension of the flange portion 220 is slightly smaller than the outer diameter dimension of the flange portion 190. The nylon cord cutting blade 40 a led out from the first lead-out hole 125 extends above the flange portion 220. The flange portion 220 corresponds to the additional flange portion referred to in the present invention.

  As shown in FIGS. 2 and 4, when the first engaging convex portion 151 and the second engaging convex portion 152 of the first clutch mechanism 150 are engaged, the main body portion 100 </ b> A of the holding member 100 and the first operation are operated. Relative rotation with the part 100B is prevented. Since the first operating portion 100B is constantly urged upward by the compression coil spring 180, the mutual engagement state between the first engaging convex portion 151 and the second engaging convex portion 152 is stable. Maintained. In addition, the first engagement convex portion 151 and the second engagement convex portion 152 have the mutual contact side surfaces 151a and 152a inclined as shown in FIG. When rotating in the driving direction, it acts to prevent detachment from the second engaging convex portion 152, and this also causes the mutual engagement state between the first engaging convex portion 151 and the second engaging convex portion 152. Is stably maintained.

  The same can be said for the second clutch mechanism 160 as described above for the first clutch mechanism 150. That is, as shown in FIG. 2 and FIG. 7, when the third engagement convex portion 161 and the fourth engagement convex portion 162 of the second clutch mechanism 160 are engaged, 2 Relative rotation with the operation unit 100C is prevented. Since the second operating portion 100C is always urged upward by the compression coil spring 181, the mutual engagement state between the third engagement convex portion 161 and the fourth engagement convex portion 162 is stable. Maintained. In addition, since the third engagement convex portion 161 and the fourth engagement convex portion 162 are inclined at the mutual contact side surfaces 161a and 162a as shown in FIG. When rotating in the driving direction, it acts to prevent detachment from the fourth engagement convex portion 162, and this also causes the third engagement convex portion 161 and the fourth engagement convex portion 162 to be in mutual engagement. Is stably maintained.

  The nylon cord cutting blades 40a and 41a are gradually shortened due to wear. In this case, the extension length of the nylon cord cutting blade 40a (41a) can be extended as follows. That is, as shown in FIG. 5 (FIG. 8), the first operating portion 100B (second operating portion 100C) is pushed down against the urging force of the compression coil spring 180 (181) and the first engaging convex portion 151 (third The engagement convex portion 161) and the second engagement convex portion 152 (fourth engagement convex portion 162) are disengaged, and the first operation portion 100B (second operation portion 100C) is connected to the nylon cord 40 (41). After the desired amount of rotation in the extending direction, the first operating portion 100B (second operating portion 100C) is moved upward by the elasticity of the compression coil spring 180 (181) to cause the first engaging convex portion 151 (third engaging convex portion). 161) and the second engagement protrusion 152 (fourth engagement protrusion 162) are engaged. Thereby, the extension length of the nylon cord cutting blade 40a (41a) is extended by the amount fed from the cord winding portion 170 (171).

  In the present embodiment, as described above, the side surfaces 151a and 152a of the first engagement convex portion 151 (third engagement convex portion 161) and the second engagement convex portion 152 (fourth engagement convex portion 162). Since (161a, 162a) is inclined, the extension length of the nylon cord cutting blade 40a (41a) can be extended by the following operation. That is, when the first operating portion 100B (second operating portion 100C) is pushed downward, the first engaging convex portion 151 (third engaging convex portion 161) and the second engaging convex portion 152 (fourth engagement). The first operating part 100B (second operating part 100C) moves downward while rotating relative to the main body part 100A due to the slope effect of the mutual contact side surfaces 151a, 152a (161a, 162a) with the joint convex part 162). To do. Then, the downward pressing force is lowered until the first engagement convex portion 151 (third engagement convex portion 161) and the second engagement convex portion 152 (fourth engagement convex portion 162) are disengaged. Then, the first operating portion 100B (second operating portion 100C) is slightly reversed by the return elastic force of the compression coil spring 180 (181) in the rotational direction, and as shown in FIG. 6 (FIG. 9), the second engaging convex portion The top surface 152b (162b) of 152 (fourth engagement convex portion 162) is placed on the top surface 151b (161b) of the first engagement convex portion 151 (third engagement convex portion 161). When the cord-like cutting member 40a (41a) is pulled outward in this state, the first engagement convex portion 151 (third engagement convex portion 161) and the second engagement convex portion 152 (fourth engagement convex portion). Part 162), the top surfaces 151b and 152b (161b and 162b) slide and the first operating part 100B (second operating part 100C) rotates, and the elastic force of the compression coil spring 180 (181) eventually causes the first engaging convexity. The portion 151 (third engagement convex portion 161) and the second engagement convex portion 152 (fourth engagement convex portion 162) automatically engage with each other. Accordingly, the extension length of the nylon cord cutting blade 40a (41a) is extended by the amount that the nylon cord 40 (41) is fed out by rotating the first operation portion 100B (second operation portion 100C).

  When performing mowing work using the mower B, for example, if the throttle opening of the engine is increased by operating a throttle lever or the like, the holding member 100 or nylon of the rotary blade A is rotated by the rotational output of the engine. The cord cutting blades 40a and 41a are rotated. By adjusting the opening of the engine throttle, the rotational speed of the nylon cord cutting blades 40a and 41a can be adjusted. The rotational output of the engine is decelerated from the transmission shaft 13 by a bevel gear (not shown) in the gear case 16 and transmitted to the holding member 100 or the nylon cord cutting blades 40a and 41a via the rotary blade mounting shaft 14. The number of rotations of the holding member 100 or the nylon cord cutting blades 40a and 41a reaches, for example, 5,000 to 6,300 rpm. When the outer diameter of the rotary blade A (the outer diameter of the flange portion 190) is, for example, 300 mm, the peripheral speed of the tip portions of the nylon cord cutting blades 40a and 41a reaches about 340 km / h. When the rotary blade A is moved along the ground, the nylon cord cutting blade 40a that turns at a high speed while the object to be cut such as weeds is prevented from entering further inward in the radial direction by the flange portion 190. , 41a, it is severed from the lateral direction and cut off.

  Moreover, in the rotary blade A of the present embodiment, a total of two nylon cords are cut from the first and second lead-out holes 125 and 127 having the same circumferential position and different axial positions of the holding member 100. The blades 40a and 41a are extended. As described above, while the rotary blade A is rotating, the nylon cord cutting blades 40a and 41a are cut while colliding with a cutting target such as weeds at high speed. Here, since the two nylon cord cutting blades 40a and 41a collide simultaneously with the object to be cut, the impact force received by the cutting object is 2 compared to the case where one nylon cord cutting blade 40a (41a) collides. Weeds with relatively thick stems and weeds that have become dry and hardened can be easily cut off. Thereby, the application range of the mowing work which can be performed using the safe cord type rotary blade A is greatly expanded.

  Unlike the case shown in FIGS. 1 and 2, the nylon cord cutting blade 41a is different from the first lead-out hole 125 through which the nylon cord cutting blade 40a is led out in a second position in the circumferential direction. May be derived from In this case, the nylon cord cutting blades 40a and 41a alternately collide with the object to be cut, and the collision frequency of the nylon cord cutting blades 40a and 41a with respect to the object to be cut even when the nylon cord cutting blades 40a and 41a have the same rotation speed. Can be increased. Even in this case, it can be expected that the cutting ability of the rotary blade A is enhanced.

  Further, in the rotary blade A of the present embodiment, the grounding member 200 supported so as to be rotatable around the rotation axis of the holding member 100 with respect to the holding member 100 or the rotary blade mounting shaft 14 is provided below the holding member 100. ing. Since the rotational driving force from the engine does not act on the grounding member 200, the holding member 100 or the nylon cord cutting blades 40a and 41a can be rotated while the grounding member 200 is in contact with the ground. Therefore, the mowing operation can be performed while moving the rotary blade A along the ground while supporting the weight of the tip of the operation tube 12 of the mowing machine B or the rotary blade A on the ground via the grounding member 200. As a result, the labor of the operator is remarkably reduced, and a high-quality mowing operation in which the heights of the stumps after mowing are aligned can be performed.

  Furthermore, in the rotary blade A of the present embodiment, the grounding member 200 has a flange portion 220, and the flange portion 220 extends radially outward from the first and second lead-out holes 125 and 127. . Among the nylon cord cutting blades 40a and 41a having different height positions, the nylon cord cutting blade 40a positioned at the lower side with the flange portion 190 interposed therebetween is positioned above the flange portion 220 in relation to the flange portion 220. Thereby, the nylon cord cutting blade 40a positioned at the lower position is guided along the circumferential direction by turning by the flange portions 190 and 220 disposed above and below the blade. According to such a configuration, even when the nylon cord cutting blade 40a is swung at high speed, the track along the circumferential direction is maintained by the flange portions 190 and 220, and fluttering up and down is suppressed. Therefore, even when a relatively hard cutting target is cut off, the high-speed turning operation of the nylon cord cutting blade 40a is maintained, and the cutting target can be cut more reliably. Thus, when the cutting ability of the nylon cord cutting blade 40a located at the lower position is enhanced, it is possible to perform a mowing operation with higher quality, which is aligned at a position where the height of the stump after mowing is low.

  As the nylon cord cutting blade 40a (41a) continues to be used, wear, breakage, or the like occurs at the tip portion, and the extension length from the first lead-out hole 125 (second lead-out hole 127) gradually decreases. To go. In such a case, the engine is stopped, and the first operating portion 100B (second operating portion 100C) of the holding member 100 is pushed down, so that the first engaging convex portion 151 (third engaging convex portion 161) and the first operating portion The second engagement protrusion 152 (fourth engagement protrusion 162) is disengaged, and the first operation portion 100B (second operation portion 100C) is rotated in the feed-out direction of the nylon cord 40 (41) and again the first The nylon cord cutting blade 40a (41a) can be easily obtained by simply engaging the first engaging convex portion 151 (third engaging convex portion 161) and the second engaging convex portion 152 (fourth engaging convex portion 162). As described above, the extension length of can be extended.

  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.

  The specific configuration for extending a plurality of cord-shaped cutting members from different positions in the axial direction of the holding member 100 (rotating blade mounting shaft 14) is not limited to the above embodiment. Three or more cord-like cutting members may be extended from different positions in the axial direction of the rotary blade mounting shaft.

  In the embodiment, the grounding member 200 is provided below the holding member 100, but whether or not the grounding member 200 is provided is a matter of choice.

  Furthermore, the mowing machine B to which the rotary blade A of the present invention is attached is not limited to the one having the rotary blade attachment shaft 14 at the tip of the operation tube 12 as shown in FIGS. 1 and 2. The rotary blade of the present invention is also attached to a so-called self-propelled mowing machine having a power source such as an engine and a rotary blade mounting shaft that is rotationally driven by this power source on a frame having wheels and movable on the ground. Can be used.

A Rotating blade B Mower 40a, 41a Nylon cord cutting blade (cord cutting member)
14 Rotating blade mounting shaft 15 Mounting bolt 100 Holding member 100A Main body portion 100B First operation portion 100C Second operation portion 110 Support piece 120 Nylon cord storage case 123 First housing portion 124 Second housing portion 125 First outlet hole 127 Second Lead hole 150 First clutch mechanism 151 First engagement convex portion 152 Second engagement convex portion 160 Second clutch mechanism 161 Third engagement convex portion 162 Fourth engagement convex portion 180, 181 Compression coil spring (elastic member)
190 Flange part 200 Grounding member 211 Center tube part 220 Flange part (additional)
230 Bearing

Claims (11)

A holding member attached to the rotary blade mounting shaft of the mower and rotated;
A cord-shaped cutting member that has a proximal end held by the holding member and a distal end side that extends radially outward of the holding member;
A rotary blade for a mowing machine, wherein a plurality of the cord-shaped cutting members are extended from a plurality of different positions in the axial direction of the mounting shaft. The holding member has a plurality of lead-out holes whose axial positions are different from each other, and is connected to the mounting shaft and rotates integrally with the mounting shaft;
A plurality of combinations that are movable with a predetermined stroke in the axial direction of the mounting shaft with respect to the main body and are relatively rotatable around the mounting shaft, and each of which holds the proximal end side of the cord-shaped cutting member An operation unit;
A plurality of elastic members each for urging the operating portion in one axial direction;
When each operation portion is in a predetermined position in the stroke due to the elasticity of the elastic member, the operation portion and the main body portion are prevented from rotating relative to each other, and each operation portion resists the elasticity of the elastic member. A plurality of clutch mechanisms that allow relative rotation between the operating portion and the main body when moved from a predetermined position;
The rotary blade for a mowing machine according to claim 1, wherein a tip side of each cord-like cutting member is led out from one of the plurality of lead-out holes. The plurality of cord-like cutting members include first and second cord-like cutting members,
The plurality of operation units include a first operation unit that holds a proximal end side of the first cord-like cutting member, and a second operation unit that holds a proximal end side of the second cord-like cutting member,
The plurality of elastic members include a first elastic member that urges the first operation portion, and a second elastic member that urges the second operation portion,
The plurality of clutch mechanisms include a first clutch mechanism that acts between the first operation portion and the main body portion, and a second clutch mechanism that acts between the second operation portion and the main body portion,
The plurality of lead-out holes are positioned higher than the first lead-out hole for leading the tip end side of the first cord-like cutting member and the first lead-out hole, and lead the tip end side of the second cord-like cutting member. The rotary blade for mowing machines according to claim 2, comprising a second outlet hole. The holding member has a flange portion having a circular outer periphery with a radius larger than the distance from the rotation axis to the far position of the first and second outlet holes,
The first cord-like cutting member led out from the first lead-out hole is extended below the flange portion,
The rotary blade for mowing machine according to claim 3, wherein the second cord-like cutting member led out from the second lead-out hole is extended above the flange portion. An additional flange portion having a circular outer periphery with a radius larger than the distance from the rotation axis of the holding member to the first outlet hole;
The rotary blade for mowing machine according to claim 4, wherein the first cord-like cutting member led out from the first lead-out hole is extended above the additional flange portion.   The rotary blade for a mowing machine according to claim 5, wherein an outer diameter dimension of the additional flange portion is smaller than an outer diameter dimension of the flange portion.   The rotary blade for a mowing machine according to claim 5 or 6, wherein the additional flange portion is rotatable relative to the holding member about a rotation axis thereof.   The rotary blade for a mowing machine according to any one of claims 3 to 7, wherein the second lead-out hole is located at a position different from the first lead-out hole in a circumferential direction around the rotation axis of the holding member.   The rotary blade for a mowing machine according to any one of claims 3 to 8, wherein the second lead-out hole is located at the same position as the first lead-out hole in a circumferential direction around the rotation axis of the holding member. The first and second elastic members always urge the first and second operation parts upward, respectively.
The first clutch mechanism includes:
A plurality of first engaging portions arranged in an annular shape around the mounting shaft in the main body;
A plurality of second engaging portions arranged in an annular shape around the mounting shaft and projecting upward and engageable with the plurality of first engaging portions;
The second clutch mechanism is
A plurality of third engaging portions arranged annularly around the mounting shaft in the main body portion;
The second operation portion includes a plurality of fourth engagement portions arranged in an annular shape around the mounting shaft, protruding upward and engageable with the plurality of third engagement portions. Item 10. A rotary blade for a mower according to any one of Items 3 to 9. A power source and a rotary blade mounting shaft that is rotationally driven by the power of the power source;
A mowing machine according to any one of claims 1 to 10, wherein the rotary blade mounting shaft is attached to the rotary blade mounting shaft.

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