Rotary blade for work machine and work machine using the same

Abstract

Provided is a rotating blade for a work machine, the rotating blade being provided with: a holding member for holding a cutting member; and a guide member rotatable relative to the holding member. This rotating blade has a structure in which the guide member can be easily attached to and removed from the holding member. To this end, the rotating blade for a work machine is provided with: an attachment shaft 14 to which rotational power is transmitted; a holding member 10 which is attached to the attachment shaft 14, rotates integrally with the shaft, and holds a cutting member 40; and a guide member 500 which is disposed below the holding member 10 and is rotatable about a rotational axis center L relative to the holding member 10. The holding member 10 is fixed to the attachment shaft 14 using a fixing shaft body 103a. The guide member 500 is supported to be able to rotate relative to the holding member 10 using a support shaft body 510 which has the same axis center as that of the attachment shaft 14 and is different from the fixing shaft body 103a.

Description

[Technical field]

[0001] The present invention relates to a rotary blade for a work machine and a work machine using the same. [Background technology]

[0002] One example of a working machine is a powered grass cutter. This grass cutter is generally configured so that a rotary blade is attached to the tip of an operating tube, and the rotational power of an engine connected to the base end of the operating tube is transmitted to the rotary blade via a transmission shaft inserted into the operating tube (see, for example, Fig. 1 of Patent Document 1). An operator holds an operating handle attached to the operating tube and swings the operating tube left and right, moving the rotary blade left and right along the ground to perform grass cutting work.

[0003] An example of a rotary blade suitable for this type of powered grass cutter is the rotary blade shown in Patent Document 1. This rotary blade is a nylon cord (cord-like cutting member) type rotary blade that is attached to the rotary blade mounting shaft of the grass cutter and rotates together with the rotary blade mounting shaft, and in addition to a holding member that holds the cord-like cutting member, it has a guide member that is supported rotatably around the rotation axis of the holding member.

[0004] In the rotary blade of the document, the rotational force from the rotary blade mounting shaft is not transmitted to the guide member, so for example, when the guide member is in contact with the ground, the guide member does not rotate, and only the holding member and the cord-like cutting blade rotate at high speed. The object to be cut, such as weeds, is prevented from entering inward beyond the outer periphery of the guide member, so it has the excellent function of being efficiently cut by the tip of the cord-like cutting member which rotates at high speed.

[0005] Incidentally, in the rotary blade shown in Patent Document 1, in order to rotatably support the guide member relative to the holding member, a bolt is used to attach the holding member to the rotary blade mounting shaft, and a bearing is interposed between this bolt and a central tube portion provided on the guide member.

[0006] Therefore, the rotary blade shown in the document could not easily select to remove only the guide member and perform work without the guide member attached. Also, to replace the guide member, the entire holding member had to be removed from the rotary blade attachment shaft. As such, the rotary blade shown in Patent Document 1 was troublesome to remove and replace the guide member, and the field of use was limited as a work machine configured with a rotary blade attached. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2013 / 054880 publication Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention was devised in light of the above-mentioned circumstances, and its object is to make it easier to attach, detach, and replace a guide member to a holding member in a rotary blade for a work machine, in which a guide member is rotatably supported by the holding member that holds a cutting member. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention employs the following technical means.

[0010] That is, the rotary blade for a work machine provided by the first aspect of the present invention comprises a holding member fixed to a mounting shaft to which rotational power is transmitted and rotates integrally with the mounting shaft, holding a cutting member, and a guide member located below the holding member and rotatable relative to the holding member about its rotational axis, the holding member being fixed to the mounting shaft using a fixing shaft body, and the guide member being supported so as to be rotatable relative to the holding member by a support shaft body separate from the fixing shaft body and having the same axis as the mounting shaft.

[0011] In a preferred embodiment, the cutting member is a cord-like cutting member having a proximal end held by the holding member.

[0012] In a preferred embodiment, the fixing shaft is a threaded shaft that is screwed onto the mounting shaft in its axial direction.

[0013] In a preferred embodiment, a bearing is interposed between the holding member and the support shaft, so that the support shaft is rotatably supported by the holding member, and the guide member is attached to the support shaft.

[0014] In a preferred embodiment, an outer ring of the bearing is fitted onto an inner surface of a cylindrical portion formed in the holding member, and an inner ring of the bearing is fitted onto an outer surface of the support shaft.

[0015] In a preferred embodiment, the central portion of the guide member is detachably attached to the lower end portion of the support shaft body.

[0016] In a preferred embodiment, the guide member has a maximum outer diameter larger than a maximum outer diameter of the holding member.

[0017] In a preferred embodiment, the guide member has a circular periphery.

[0018] In a preferred embodiment, the guide member has an outer periphery that is an irregular shape other than circular.

[0019] In a preferred embodiment, the retaining member comprises a holder that rotates integrally with the mounting shaft, and a case body, the case body having a case first member that is combined with the holder so as to be unable to rotate relative to the holder around the axis of the mounting shaft but movable relative to the holder in the axial direction of the mounting shaft, and a case second member that is combined with the holder so as to be unable to move relative to the case first member in the vertical direction but rotatable relative to the case first member about the axis of the mounting shaft, and the case body is constantly elastically biased downwardly relative to the holder, the case second member holds a cord-shaped cutting member having a base end wound around it and a tip end extending radially outward from the side wall of the case first member, the holder having a plurality of first engaging protrusions that protrude upwardly and are arranged in a ring shape centered on the mounting shaft, and the case second member having a plurality of second engaging protrusions that protrude downwardly and are arranged in a ring shape centered on the mounting shaft and are engageable with the first engaging protrusions.

[0020] In a preferred embodiment, the holder has a downward cylindrical portion having a spline groove formed on its outer periphery, and the case first member has an upward cylindrical portion having a spline groove formed on its inner periphery that engages with the spline groove of the downward cylindrical portion, such that the case first member is unable to rotate relative to the holder but can move relative to it in the axial direction of the mounting shaft.

[0021] In a preferred embodiment, the holder has a second downward cylindrical portion radially outside the downward cylindrical portion with an annular space interposed therebetween, and the upward cylindrical portion of the case first member is inserted into the annular space.

[0022] In a preferred embodiment, the case second member has a reel portion located inside the case first member, and the base end of the cord-shaped cutting blade is wound around the reel portion and the tip end extends outside the case body through an outlet hole formed in the side wall of the case first member.

[0023] In a preferred embodiment, the lower end of a compression coil spring fitted around the outer periphery of the second downward cylindrical portion of the holder is elastically contacted with the reel portion, thereby elastically biasing the case body downward relative to the holder.

[0024] A work machine provided according to a second aspect of the present invention comprises a power source and a mounting shaft that is rotationally driven by the power source, and the mounting shaft has a rotary blade for a work machine according to the first aspect attached thereto.

[0025] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings. [Brief description of the drawings]

[0026] [Figure 1] 1 is an overall perspective view of an example of a grass mower equipped with a rotary blade according to an embodiment of the present invention; [Diagram 2] 1 is a cross-sectional view of a rotary blade according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 3 is a diagram for explaining the operation, which is a diagram equivalent to the cross section shown in FIG. [Diagram 5] 5 is an explanatory view of the operation of the rotary blades shown in FIGS. 2 to 4, and corresponds to a cross section taken along line VV in FIG. [Figure 6] 5 is an explanatory view of the operation of the rotary blades shown in FIGS. 2 to 4, and corresponds to a cross section taken along line VV in FIG. [Figure 7] 5 is an explanatory view of the operation of the rotary blades shown in FIGS. 2 to 4, and corresponds to a cross section taken along line VV in FIG. [Figure 8] FIG. 5 is a cross-sectional view of a rotary blade according to a second embodiment of the present invention. [Figure 9] FIG. 5 is a cross-sectional view of a rotary blade according to a third embodiment of the present invention. [Figure 10] FIG. 11 is a cross-sectional view of a rotary blade according to a fourth embodiment of the present invention. [Figure 11] 1 is a schematic explanatory diagram of an example of use of a rotary blade according to the present invention; [Figure 12] 1 is a schematic explanatory diagram of an example of use of a rotary blade according to the present invention; [Figure 13] 1 is a schematic explanatory diagram of an example of use of a rotary blade according to the present invention; [Figure 14] 1 is a schematic explanatory diagram of an example of use of a rotary blade according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0028] 1 to 4 show an embodiment of a rotary blade A1 for a work machine according to the first embodiment of the present invention and a grass cutter B1 as an example of a work machine using the rotary blade A1. As shown in FIG. 1, in the grass cutter B1, a small engine 11 is connected to the base end of an operating tube 12 as a drive source, and the rotation output is transmitted to the tip of the operating tube 12 via a transmission shaft 13 inserted into the operating tube 12. As the small engine 11, a gasoline engine with a displacement of about 25 cc is used in consideration of portability by the operator. The small engine 11 may be directly attached to the base end of the operating tube 12, or an engine mounted on a backpack may be connected via a flexible transmission shaft. As shown in FIG. 2, a mounting shaft 14 is supported on a gear case 16 at the tip of the operating tube 12, and the mounting shaft 14 and the transmission shaft 13 are linked by a bevel gear mechanism (not shown). The mounting shaft 14 has a spline formed on its outer periphery, and a screw hole 14a extending in the axial direction is formed at the shaft end. A metallic rotary blade holder 17 is spline-fitted onto the mounting shaft 14.

[0029] A rotary blade A1 characterized by the present invention is attached to the mounting shaft 14 of the grass cutter B1.

[0030] This rotary blade A1 includes a holding member 10 that is attached to a mounting shaft 14 and rotated integrally with the mounting shaft 14, and a guide member 500 that is supported so as to be rotatable relative to the holding member 10 about the axis L of the mounting shaft 14. The holding member 10 is a member for holding the base end side of a cord-like cutting member 40 serving as a cutting member as described below, and in this embodiment includes a holder 100 and a case body 200 that wraps around and holds the base end side of the cord-like cutting member 40 and causes the tip side to extend radially outward.

[0031] The holder 100 is preferably made of metal and has a rotating body shape having an outer peripheral flange portion 120 and a downward cylindrical portion 110. The holder 100 is fixed to the mounting shaft 14 by threading a bolt 103, which is inserted from below into a center hole 102 of the holder 100, into a screw hole 14a of the mounting shaft 14. In this state, the upper surface of the holder 100 is pressed against the rotary blade holder 17. A spline groove 111 is formed on the outer periphery of the downward cylindrical portion 110, and a plurality of first engaging protrusions 130 are formed on the upper surface of the outer peripheral flange portion 120, which are arranged at equal intervals in an annular shape. The first engaging protrusions 130 will be described in more detail later. The bolt 103 corresponds to the fixing shaft 103a in the present invention.

[0032] The case body 200 is configured by combining a case first member 210 and a case second member 230, which are made of, for example, synthetic resin.

[0033] The case first member 210 has a shape of a revolution body having an upward cylindrical portion 211, a partition wall portion 212 closing the lower end of the upward cylindrical portion 211, a cylindrical body portion 214 hanging down from the outer periphery of the partition wall portion 212, a doughnut-shaped bottom wall portion 215 extending radially outward from the lower end of the cylindrical body portion 214, and a side wall portion 216 rising upward from the outer periphery of the bottom wall portion 215. A spline groove 217 that engages with the spline groove 111 of the downward cylindrical portion 110 of the holder 100 is formed on the inner periphery of the upward cylindrical portion 211. This makes the case first member 210 non-rotatable relative to the holder 100 and relatively movable in the direction of the axis L of the mounting shaft 14. The partition wall portion 212 is formed with a boss portion 218 for providing a structure for supporting a guide member 500 described later. A spring receiving step 219 is formed on the outer periphery of the partition wall 212 at the lower end of the upward cylindrical portion 211. The cylindrical body portion 214, the bottom wall portion 215, and the side wall portion 216 cooperate to form an annular groove space S that is open upward. The first case member 210 is constantly elastically biased downward by making the upper end of a compression coil spring 300, which is fitted on the outer periphery of the upward cylindrical portion 211, elastically contact the lower surface of the holder 100 and making the lower end elastically contact the spring receiving step 219. Two cord reeling holes 220 are formed in the side wall portion 216 in radially opposed positions, and a collar 221 with excellent wear resistance is fitted into the reeling hole 200.

[0034] Case second member 230 has a rotating body shape having an upper cover portion 240 exposed to the outside, and a reel portion 250 located in annular groove space S of case first member 210. Cover portion 240 has an inward flange portion 242 having a hole 241 on its inner periphery that is fitted onto upper bulging portion 101 of holder 100, and an outer periphery skirt portion 243 that hangs down while being rounded from the outer periphery of inward flange portion 242.

[0035] The outer peripheral skirt portion 243 has outwardly facing concave engagement portions 244 formed at multiple circumferentially spaced locations, each of which is formed by an elastic claw 244a and a downward support wall 244b. By engaging these concave engagement portions 244 with an inwardly facing flange 216a formed on the upper end of the side wall portion 216 of the case first member 210 with a slight amount of play, the case first member 210 and the case second member 230 are unable to move relative to each other in the vertical direction, but can rotate relative to each other around the axis L of the mounting shaft 14.

[0036] A plurality of second engaging protrusions 260 are formed on the underside of the inward flange portion 242 of the cover portion 240 of the case second member 230, protruding downward and arranged at equal intervals in an annular shape centered on the mounting shaft 14, and capable of engaging with the first engaging protrusions 130 of the holder 100. The second engaging protrusions 260 will be described in detail later.

[0037] The reel section 250 is integrated with the cover section 240 via a connecting wall 255 that hangs down from the inner surface of the cover section 240, and has a shape of a revolution body having an upper horizontal wall 251 that extends radially inward from the connecting wall 255, a winding trunk section 252 that hangs down from the inner periphery of the upper horizontal wall 251 along the outer periphery of the cylindrical trunk section 214 of the case first member 210, and a lower horizontal wall 253 that extends radially outward from the lower end of the winding trunk section 252 along the bottom wall section 215 of the case first member 210. The base end side of a cord-like cutting member 40 such as a nylon cord is wound and held around this reel section 250, and the tip side is paid out to the outside of the case body 200 through a cord pay-out hole 220. Specifically, the cord-like cutting member 40 is long, for example, about 3 m to 5 m long and about 3 mm in diameter. For example, the cord-like cutting member 40 is passed through two through holes 251a in the upper horizontal wall 251 of the reel unit 250, and the middle part is held by the upper horizontal wall 251. The two cord-like cutting members 40 are wound around the winding body 252, and the two tip parts 40a are pulled out to the outside through the two cord-releasing holes 220 described above, and are held in the case body 200. The winding direction of the cord-like cutting member 40 on the reel unit 250 is determined depending on the rotation direction of the rotary blade A1, and is set to the opposite direction to the rotation direction of the rotary blade A1. Since the mounting shaft 14 of the grass cutter B1 usually rotates counterclockwise (left), the rotary blade A1 also rotates left. In this case, the winding direction of the cord-like cutting member 40 is set to the clockwise (right) direction (FIG. 3).

[0038] In this embodiment, the cover portion 240 and the reel portion 250 constituting the second case member 230 are formed separately for the convenience of molding, and then integrated by an appropriate means such as a bayonet-type connecting means 245.

[0039] The case first member 210 and the case second member 230 are linked together by engaging the inward flange 216a formed on the upper end of the side wall portion 216 of the case first member 210 with a small amount of play in the outward concave engagement portion 244 formed by the elastic claw 244a and the downward support wall 244b. This is to make it possible to easily separate the case first member 210 and the case second member 230 by pushing in the elastic claw 244a to release the engagement with the inward flange 216a. This is convenient for replacing the cord-shaped cutting member 40. To combine the case second member 230 with the case first member 210, it is only necessary to position the case first member 210 and the case second member 230 concentrically and push them toward each other. As a result, the elastic claw 244a elastically overcomes the inward flange 216a and automatically engages with the inward flange 216a.

[0040] 5 is a cross-sectional view taken along line VV in FIG. 2, showing the relationship between the first engaging protrusion 130 of the holder 100 and the second engaging protrusion 260 of the case second member 230 (cover part 240). The rotational force from the mounting shaft 14 or the holder 100, indicated by the arrow N in FIG. 5, is transmitted from the first engaging protrusion 130 of the holder 100 to the second engaging protrusion 260 of the case second member 230. The first engaging protrusion 130 on the driving side has a cross-sectional inclined trapezoid shape having a rotational front surface 131, a rotational rear surface 132, and a horizontally flat top surface 133. That is, both the rotational front surface 131 and the rotational rear surface 132 are inclined toward the front in the rotational direction as they go upward.

[0041] On the other hand, the second engagement protrusion 260 on the driven side also has an inclined trapezoidal cross-sectional shape having a rotational front surface 261, a rotational rear surface 262, and a horizontally flat top surface 263, but the inclination direction is opposite to that of the first engagement protrusion 130, and both the rotational front surface 261 and the rotational rear surface 262 are inclined toward the rear in the rotational direction as they extend downward.

[0042] The formation pitch of the first engagement protrusions 130 and the second engagement protrusions 260 is the same in the circumferential direction of a circle centered on the mounting shaft 14, and normally, as shown in Fig. 5, the first engagement protrusions 130 and the second engagement protrusions 260 are engaged with each other by the elastic force of the compression coil spring 300 described above, and the rotational force of the holder 100 is transmitted to the case second member 230. In addition, since the case first member 210 rotates integrally with the holder 100, in this state the entire case body 200 receives the rotational force from the mounting shaft 14 and rotates counterclockwise at high speed.

[0043] The guide member 500 is attached to the case first member 210 so as to be relatively rotatable about the axis L of the mounting shaft 14. In this embodiment, this is configured by screwing a bolt 501 from below into a nut member 218a fitted into a boss portion 218 provided on the partition wall portion 212 of the case first member 210 to form a support shaft 510, and interposing a bearing 530 between a central boss portion 520 of the guide member 500 and the support shaft 510. The bolt 501 corresponds to the support shaft body 510 of the present invention. In this embodiment, an outer ring 531 of the bearing 530 is fitted into the inner surface of a central boss portion 520 of the guide member 500, which will be described later, and an inner ring 532 is fitted into the outer surface of the support shaft 510.

[0044] The guide member 500 is made of metal near the central boss portion 520 and resin for the remaining portion, and has a generally circular disk shape with a circular outer periphery. In this embodiment, the guide member 500 has an outer portion 550 stepped up from a horizontal inner portion 540 located below the case body 200, so that the distance between the upper surface of the outer portion 550 and the cord-like cutting member 40 is set to a predetermined value or less. The outer diameter of the guide member 500 is larger than the outer diameter of the case body 200, and preferably, the outer diameter of the guide member 500 is 1.5 times or more the outer diameter of the case body 200.

[0045] This guide member 500 is rotatable relative to the holding member 10, specifically the case first member 210, so that the rotational force from the holding member 10 is not basically transmitted to the guide member 500. Therefore, when the guide body 500 is in contact with an external object, for example, by contacting the ground, the guide member 500 maintains a stationary state even if the holding member 10 is rotating at high speed.

[0046] When the tip side of the cord-shaped cutting member 40 extends radially outward from the holding member 10, it further extends a predetermined length, for example, about 3 to 6 cm, from the outer circumferential edge of the guide member.

[0047] Next, the operation of the rotary blade A1 for a work machine having the above-mentioned configuration will be described.

[0048] As described above, in the normal state, the first case member 210 is urged downward by the elastic force of the compression coil spring 300, and is therefore located at the lower end of the movement stroke relative to the holder 100. The lower end of the movement stroke is determined by the engagement of the second engagement protrusion 260 of the second case member 230 (cover part 240) with the first engagement protrusion 130 of the holder 100 (FIGS. 2 and 5). That is, in this normal state, the case body 200 rotates integrally with the holder 100. When the rotation speed of the small engine 11 is increased, the internal clutch of the engine is engaged and the rotation force is transmitted to the mounting shaft 14, and the entire holding member 10 rotates at high speed. However, as described above, the rotation force is not transmitted to the guide member 500, which has a certain amount of mass, so the case body 200 reaches a predetermined high-speed rotation speed in a short time. In conjunction with this, the cord-shaped cutting member 40 also rotates at high speed, which strikes the weeds, etc. with a large kinetic energy to perform the cutting action. At this time, the outer peripheral edge of the guide member 500 prevents the weeds, etc. from entering radially inward of the rotary blade A1. Therefore, the weeds, etc. are cut by the tip portion 40a of the cord-shaped cutting member 40, i.e., the portion having a high peripheral speed, resulting in very good cutting efficiency. In addition, since the guide member 500 can be brought into contact with an external object while rotating the holding member 10 at high speed, the guide member 500 can be slid against the ground to perform grass cutting work. Therefore, the weeds, etc. can be neatly and efficiently cut from near their roots.

[0049] As the grass cutting operation continues, the tip of the cord-like cutting member 40 wears down and the extension length from the periphery of the case body 200 or the guide member 500 becomes shorter. With this rotary blade A1, the extension length of the cord-like cutting member 40 can be easily restored as follows.

[0050] When the engine 11 is returned to an idling condition, the internal clutch ceases power transmission and the mounting shaft 14 and / or the retaining member 10 stop rotating.

[0051] In this state, the entire rotary blade A1 is pressed against the ground with a predetermined pressure by, for example, pushing the operating tube 12 of the grass cutter B1 downward. Then, as shown in Fig. 4, the case second member 230 moves upward against the elastic force of the compression coil spring 300 relative to the holder 100. This releases the engagement of the second engagement protrusion 260 of the case second member 230 (cover part 240) with the first engagement protrusion 130 of the holder 100 (Fig. 6), and the case second member 230 becomes rotatable relative to the case first member 210.

[0052] The case second member 230, which is integral with the reel portion 250, rotates slightly in the opposite direction (clockwise) to the rotational direction (counterclockwise) of the rotating blade A1 relative to the case first member 210 due to the unwinding force of the cord-like cutting member 40 wound around the reel portion 250, and as shown in Figure 6, the top surface 263 of the second engagement protrusion 260 of the case second member 230 appears to be resting on the top surface 133 of the first engagement protrusion 130 of the holder 100.

[0053] Next, when the engine speed is increased to rotate the case first member 210, a centrifugal force acts on the tip of the cord-shaped cutting member 40, pulling it radially outward from the rotating blade A1, causing the case second member 230 to rotate clockwise relative to the case first member 210. Eventually, under the action of the compression coil spring 300, the case first member 210 and the case second member 230 move downward and the second engagement protrusion 260 engages with the first engagement protrusion 130 adjacent to the first engagement protrusion 130 with which it had been engaged (Figure 7), and then the case second member 230 begins to rotate integrally with the case first member 210.

[0054] By the above action, the case second member 230 rotates together with the reel portion 250 in the direction of unwinding the cord-like cutting member 40 relative to the case first member 210 by an angle corresponding to the formation pitch of the first engaging protrusions 130 and the second engaging protrusions 260. As a result, the extension length of the cord-like cutting member 40 is extended by a length corresponding to the formation pitch of the first engaging protrusions 130 and the second engaging protrusions 260.

[0055] In the end, the rotary blade A1 having the above configuration can restore the extension length of the cord-shaped cutting member 40 simply by pressing the entire rotary blade A1 against the ground after stopping its rotation, releasing the pressing force, and rotating it again.

[0056] Furthermore, in the rotary blade A1 having the above configuration, the guide member 500 is supported so as to be rotatable relative to the holding member 10 using a support shaft 510 (bolt 501) that is different from the fixing shaft 103a (bolt 103) for attaching the holding member 10 to the mounting shaft 14 of the grass cutter B1, so that the guide member 500 can be removed from the holding member 10 while the holding member 10 remains attached to the mounting shaft 14.

[0057] This makes it easy to choose to remove the guide member 500 and perform work without using the guide member 500, and also makes it easy to replace it with a different type of guide member 500, thereby expanding the field of use of the work machine.

[0058] FIG. 8 shows an embodiment of a rotary blade A2 for a work machine according to a second embodiment of the present invention and a grass cutter B2 as an example of a work machine in which the rotary blade A2 is used, and is a diagram corresponding to FIG. 2 showing the rotary blade A1 for a work machine according to the first embodiment.

[0059] The rotary blade A2 differs from the rotary blade A1 according to the first embodiment described above in the mounting structure of the guide member 500 to the case first member 210, but the remaining configuration is basically the same as that of the rotary blade A1 according to the first embodiment. In Fig. 8, the same members or parts as those of the rotary blade A1 and the grass cutter B1 according to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0060] This rotary blade A2 also includes a holding member 10 that is attached to a mounting shaft 14 and rotated integrally with the mounting shaft 14, and a guide member 500 that is supported relative to the holding member 10 so as to be rotatable around the axis L of the mounting shaft 14.

[0061] In the rotary blade A1 according to the first embodiment, the guide member 500 is supported rotatably relative to the case first member 210 by interposing a bearing 530 between a bolt 501 (support shaft 510) fixedly attached to the case first member 210 and a central boss portion 520 of the guide member 500, but in the rotary blade A2 according to the second embodiment, the support shaft 510 is rotatably supported on the inner surface of the cylindrical body portion 214 of the case first member 210 via the bearing 530, and the guide member 500 is fixedly attached to the support shaft 510. This will be described below.

[0062] As shown in FIG. 8, an outer ring 531 of a bearing 530 is fitted and held on the inner surface of the cylindrical body 214 of the case first member 210 via a metallic reinforcing member 214a, and a support shaft body 510 is fitted inside the inner ring 532 of the bearing 530. The support shaft body 510 is located on the rotation axis L of the holding member 10. This allows the support shaft body 510 to rotate relative to the case first member 210. In this embodiment, the support shaft body 510 is composed of a nut member 512 having a head portion 511. In this embodiment, which has such an arrangement structure of the support shaft body 510, the partition wall portion 212 formed on the case first member 210 in the first embodiment is omitted. The guide member 500 is supported by the nut member 512 (support shaft body 510) by screwing a bolt 513 passed through the central boss portion 520 from below into the nut member 512. As a result, the guide member 500 is supported so as to be relatively rotatable about the rotation axis L of the holding member 10 relative to the case first member 210, that is, the holding member 10.

[0063] Next, the operation of the rotary blade A2 for a work machine having the above-mentioned configuration will be described.

[0064] This rotary blade A2 also has the same basic function as a rotary blade for cutting weeds, etc., and the function of restoring the extension length of the cord-shaped cutting member 40 as described above for the rotary blade A1 of the first embodiment.

[0065] In the rotary blade A2 of this embodiment, the guide member 500 is supported so as to be rotatable relative to the holding member 10 using a support shaft 510 (nut member 512) that is different from the fixing shaft 103a (bolt 103) for attaching the holding member 10 to the mounting shaft 14 of the grass cutter B2. Therefore, the guide member 500 can be removed from the holding member 10 while the holding member 10 remains attached to the mounting shaft 14.

[0066] In addition, the rotary blade A2 according to this embodiment employs a configuration in which the guide member 500 is supported by the support shaft body 510 (nut member 512) rotatably supported via a bearing 9530 on the cylindrical body portion 214 of the case first member 210, by screwing the bolt 513 passing through the central boss portion 520 from below. Therefore, the guide member 500 can be more easily removed from the holding member 10 by simply removing the bolt 513.

[0067] Fig. 9 shows an embodiment of a rotary blade A3 for a work machine according to a third embodiment of the present invention and a grass cutter B3 as an example of a work machine using the rotary blade A3, and corresponds to Fig. 2 showing the rotary blade A1 for a work machine according to the first embodiment. In Fig. 9, members or parts equivalent to those of the rotary blades A1 and A2 and the grass cutters B1 and B2 according to the first and second embodiments are given the same reference numerals and descriptions thereof are omitted as appropriate.

[0068] This rotary blade A3 differs from the rotary blade A2 according to the second embodiment described above in details of the holder 100, the case first member 210, and the case second member 230 that constitute the holding member 10. The details will be described below.

[0069] In this embodiment, in addition to the outer peripheral flange portion 120 and the downward cylindrical portion 110, the holder 100 has a second downward cylindrical portion 110a formed on the outer periphery of the downward cylindrical portion 110 via an annular space Sa. The annular space Sa is cylindrical, and the upward cylindrical portion 211 of the case first member 210 is inserted into this annular space Sa so as to be slidable in the vertical direction. The compression coil spring 300 is inserted into the second upward cylindrical portion 110a, and its upper end is elastically contacted with the lower surface of the holder 100, and its lower end is elastically contacted with the upper surface of the reel portion 250. A protrusion 254 is formed on the inner peripheral portion of the lower surface of the reel portion 250, and this protrusion 254 is abutted against the donut-shaped bottom wall portion 215 of the case first member 210. As a result, the elastic force of the compression coil spring 300 is transmitted to the case first member 210, and the entire case body 200 is constantly biased downward.

[0070] The first engagement protrusion 130 is formed on the upper surface of the outer peripheral flange portion 120 of the holder 100, the downward cylindrical portion 110 of the holder 100 and the upward cylindrical portion 211 of the case first member 210 are spline-engaged, and the case first member 210 cannot rotate relative to the holder 100 but can move relative to it in the direction of the axis L of the mounting shaft 14, as described above for the rotary blade A1 of the first embodiment and the rotary blade A2 of the second embodiment.

[0071] As described above, the case body 200 in this embodiment has a configuration similar to that of the rotary blade A1 in the first embodiment and the rotary blade A2 in the second embodiment, except that the upward cylindrical portion 211 of the case first member 210 is inserted into the annular space Sa formed in the holder 100, and the elastic force of the compression coil spring 300 is transmitted to the case first member 210 and the case second member 230 via the reel portion 250, and in addition, a protective flange 222 is integrally formed on the outer periphery of the case first member 210, extending radially above the cord-shaped cutting member 40 at a predetermined interval.

[0072] That is, the reel portion 25 is integrally connected to the case second member 230, and the base end side of the cord-like cutting member 40 such as a nylon cord is wound and held thereon, while the tip side is reeled out to the outside of the case body 200 through the cord reel-out hole 220; the case first member 210 and the case second member 230 cannot move relative to each other in the vertical direction, but can rotate relative to each other around the axis L of the mounting shaft 14; and the underside of the inward flange portion 242 of the cover portion 240 of the case second member 230 is formed with a plurality of second engaging protrusions 260 that protrude downward, are arranged at equal intervals in a ring shape centered on the mounting shaft 14, and are capable of engaging with the first engaging protrusion 130 of the holder 100, which are similar to the rotary blade A1 of the first embodiment and the rotary blade A2 of the second embodiment described above.

[0073] In this embodiment, like the first and second embodiments, the guide member 500 has an outer diameter larger than the outer diameter of the case body 200, preferably 1.5 times or more the outer diameter of the case body 200. However, the configuration for supporting the guide member 500 so as to be rotatable relative to the case first member 210 is similar to that of the rotary blade A2 in the second embodiment, in which a support shaft 510 is rotatably supported on the inner surface of the cylindrical body portion 214 of the case first member 210 via a bearing 530, and the guide member 500 is fixedly attached to the support shaft 510.

[0074] Next, the operation of the rotary blade A3 for a work machine having the above-mentioned configuration will be described.

[0075] This rotary blade A3 also has the same basic rotary blade cutting function for cutting weeds, etc., and the function of restoring the extension length of the cord-shaped cutting member 40 as described above for the rotary blade A2 of the first embodiment.

[0076] As for the rotary blade A3 according to this embodiment, the guide member 500 is supported rotatably relative to the holding member 10 by using a support shaft 510 (nut member 512) that is different from the fixing shaft 103a (bolt 103) for mounting the holding member 10 to the mounting shaft 14 of the grass cutter B3, so that the guide member 500 can be removed from the holding member 10 while the holding member 10 is mounted on the mounting shaft 14. Note that in this embodiment, as in the second embodiment, the support shaft 510 is rotatably supported on the inner surface of the cylindrical body 214 of the case first member 210 via a bearing 530, and the guide member 500 is fixedly mounted to the support shaft 510, so that the guide member 500 can be more easily removed from the holding member 10 by simply removing the bolt 513.

[0077] In this embodiment, the upward cylindrical portion 211 of the case first member 210 is inserted into the annular space Sa between the downward cylindrical portion 110 and the second downward cylindrical portion 110a of the holder 100 so as to be slidable in the vertical direction, so that the concentricity of the case first member 210 with the holder 100 is more accurately maintained. Therefore, the rotary blade A3 can be rotated at high speed more stably without causing unnecessary vibration.

[0078] Furthermore, in this embodiment, a protective flange 222 extending radially above the cord-like cutting member 40 at a predetermined interval is integrally formed on the outer periphery of the first case member 210. Therefore, during high-speed rotation of the rotating blade A3, the degree to which the cord-like cutting member 40 swings up and down around the exit of the cord pay-out hole 220 as a fulcrum in reaction to a collision with an external object can be kept below a predetermined level. As a result, it is possible to prevent the cord-like cutting member 40 from being torn off near the exit of the cord pay-out hole 220 during operation, and stable grass cutting work can be continued.

[0079] Fig. 10 shows an embodiment of a rotary blade A4 for a work machine according to a fourth embodiment of the present invention and a grass cutter B4 as an example of a work machine using the rotary blade A4, and corresponds to Fig. 2 showing the rotary blade A1 for a work machine according to the first embodiment. In Fig. 10, members or parts equivalent to those of the rotary blades A1, A2, A3 and the grass cutters B1, B2, B3 according to the first, second and third embodiments are given the same reference numerals and descriptions thereof are omitted as appropriate.

[0080] The rotary blade A4 according to the fourth embodiment differs from the rotary blade A3 according to the third embodiment only in the shape of the guide member 500, and the other configurations are similar to those of the rotary blade A3 according to the third embodiment.

[0081] In this embodiment, the guide member 500 has an outer diameter substantially equal to the outer diameter of the case body 200, and is shaped to bulge downward in a dome shape.

[0082] According to such a configuration, a grass-cutting method can be adopted in which the guide member 500 is placed on the ground in a stationary state, the entire rotary blade A4 is tilted significantly relative to the ground, and the target weeds, etc. are cut from the roots.

[0083] The rotary blades A1, A2, A3, and A4 according to the first, second, third, and fourth embodiments have been described above, but each of these rotary blades A1, A2, A3, and A4 has a feature in that the guide member 500 can be easily attached and detached to and from the holding member 10 while the holding member 10 remains attached to the mounting shaft of the mower B1, B2, B3, and B4. This means that the guide member 500 can be easily replaced with a different type of guide member 500 as necessary.

[0084] For example, as shown in FIG. 11, by replacing the guide member 500a with one having a rectangular outer shape, it is possible to neatly mow grass even in the corners of land partitioned by right-angled walls C.

[0085] Alternatively, as shown in FIG. 12, by replacing it with a guide member 500b having a smaller diameter, the grass cutting work inside the U-shaped ditch D can be performed while the guide member 500b is placed on the opening edge of the U-shaped ditch.

[0086] Furthermore, as shown in Figure 13, by replacing the guide member 500c having a notch 560 on its outer periphery and using the cord-shaped cutting member 40 so that the tip of the cord-shaped cutting member 40 is roughly aligned with the outer periphery of the guide member, weeds around the trunk E of a tree can be neatly cut without damaging the trunk.

[0087] Furthermore, as shown in FIG. 14, by attaching the rotary blade A2 to an appropriate working machine (not shown) and using a guide member 500d with wheels, it is possible to neatly cut the stems of vegetables F such as onions.

[0088] Of course, the scope of the present invention is not limited to the above-described embodiment, and all modifications within the scope of the claims are encompassed within the scope of the present invention.

[0089] The candy-shaped holding member 10 that holds the base end of the cord-like cutting member 40 is not limited to the embodiment in which the long cord-like cutting member 40 is stored in a wound state in the case body 200 and the end is appropriately unwound, but any type of holding member structure can be used. For example, the present invention can be applied to a rotary blade having a holding member structure that holds the base end of a cord-like cutting member of a predetermined length, such as that shown in Japanese Patent No. 5972275.

[0090] Furthermore, the working machine to which the rotary blades A1, A2, A3, A4 are attached does not have to be a grass cutter, but may be any working machine B having an attachment shaft 14 that is rotationally driven by power. [Explanation of symbols]

[0091] A1, A2, A3, A4: Rotary blade B1, B2, B3, B4: Grass cutter S: Annular groove space Sa: Annular space 10: Holding member 11: Small engine 12: Operation tube 13: Transmission shaft L: Axis line N: Rotation direction S: Annular groove space 14: Mounting shaft 14a: screw hole 16: Gear case 17: Rotary blade holder 40: Cord-shaped cutting member 40a: Tip 100: Holder 101:bulge 102: Center hole 103: Bolt 110: Downward-facing cylinder 110a: Downward cylindrical section 111: Spline groove 120: Flange part 130: First engagement convex part 131: Front rotation 132: Rotation direction rear surface 133:Top surface 200: Case body 210: Case first member 211: Upward-facing cylinder 212: Partition wall 212a: Nut member 213: Bottom wall 214: barrel body 215: Bottom wall 216: Side wall 216a: Inward flange 217: Spline groove 218: Boss Department 218a: Nut member 219: Spring receiving step 220: Cord outlet hole 221:Color 222: Protective flange 230: Case second member 240: Cover part 241: Hole 242: Inner flange part 243: Outer skirt 244:Outward concave engagement part 244a: Elastic claw 244b: Support wall 245: Connection means 250: Reel section 251: Upper horizontal wall 251a:Through hole 252: Rolled body 253: Lower horizontal wall 254: Protrusion 255: Connecting wall 260:Second engagement protrusion 261: Front rotation direction 262: Rotation direction rear 263:Top surface 300: Compression coil spring 500: Guide material 501: Bolt 510: Support shaft 520: Center boss 530: Bearing 540: Inner part 550: Foreign Department

Claims

1. a holding member fixed to a mounting shaft to which rotational power is transmitted and rotates integrally with the mounting shaft, and holding the cord-shaped cutting member; a guide member located below the holding member and rotatable relative to the holding member about a rotation axis thereof; Equipped with The holding member is fixed to the mounting shaft by using a fixing shaft body, The guide member is supported by a support shaft body, which is different from the fixing shaft body and has the same axis as the mounting shaft, so as to be rotatable relative to the holding member, The holding member includes a holder that rotates integrally with the mounting shaft and a case body, the case body has a case first member that is combined with the holder so as to be unable to rotate relative to the holder about the axis of the mounting shaft but movable relative to the holder in the axial direction of the mounting shaft, and a case second member that is combined with the case first member so as to be unable to move relative to the holder in the vertical direction but rotatable relative to the holder about the axis of the mounting shaft, and is constantly elastically biased downward with respect to the holder; the case second member holds the cord-shaped cutting member, the base end of which is wound around the case second member and the tip end of which extends radially outward from the side wall of the case first member; The holder has a plurality of first engagement protrusions that protrude upward and are arranged in an annular shape around the mounting shaft, The case second member has a plurality of second engaging protrusions that protrude downward, are arranged in an annular shape around the mounting shaft, and are engageable with the first engaging protrusions. A rotary blade for a work machine, characterized in that

2. 2. The rotary blade for a work machine according to claim 1, wherein the fixing shaft body is a threaded shaft that is screwed onto the mounting shaft in its axial direction.

3. 3. A rotary blade for a work machine as described in claim 1 or 2, wherein the support shaft is rotatably supported relative to the holding member by interposing a bearing between the holding member and the support shaft, and the guide member is attached to the support shaft.

4. 4. The rotary blade for a work machine according to claim 3, wherein an outer ring of the bearing is fitted onto an inner surface of a cylindrical portion formed on the holding member, and an inner ring of the bearing is fitted onto an outer surface of the support shaft.

5. 5. The rotary blade for a work machine according to claim 3, wherein a central portion of said guide member is detachably attached to a lower end portion of said support shaft body.

6. 6. The rotary blade for a work machine according to claim 1, wherein the guide member has a maximum outer diameter larger than a maximum outer diameter of the holding member.

7. 7. The rotary blade for a work machine according to claim 1, wherein the guide member has an outer periphery that is circular.

8. 7. The rotary blade for a work machine according to claim 1, wherein the outer periphery of said guide member is an irregular shape other than a circle.

9. 2. A rotary blade for a work machine as described in claim 1, wherein the holder has a downward cylindrical portion having a spline groove formed on its outer periphery, and the case first member has an upward cylindrical portion having a spline groove formed on its inner periphery that engages with the spline groove of the downward cylindrical portion, thereby making the case first member unable to rotate relative to the holder but able to move relative to it in the axial direction of the mounting shaft.

10. The rotary blade for a work machine as described in claim 9, wherein the holder has a second downward cylindrical portion radially outside the downward cylindrical portion via an annular space, and the upward cylindrical portion of the case first member is inserted into the annular space.

11. A rotary blade for a work machine as described in claim 1, 9 or 10, wherein the case second member has a reel portion located inside the case first member, and the cord-shaped cutting member has a base end side wound around the reel portion and a tip side extending outside the case body from an extension hole formed in a side wall of the case first member.

12. The rotary blade for a work machine as described in claim 10, wherein the lower end of a compression coil spring inserted around the outer periphery of the second downward cylindrical portion of the holder is elastically contacted with the reel portion, thereby elastically biasing the case body downward relative to the holder.

13. A power source and a mounting shaft that is rotationally driven by the power source, A work machine, characterized in that the rotary blade for a work machine according to any one of claims 1 to 12 is attached to the mounting shaft.

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