Work machine

Abstract

To provide a technique capable of reducing vibration of a housing caused by oscillation of a work member.SOLUTION: The specification discloses a work machine. The work machine includes: a housing; a work member supported by the housing so as to be able to oscillate, and at least partially arranged in the outside of the housing; and a counterweight arranged in the inside of the housing and oscillating when the work member oscillates. The work member and the counterweight oscillate so as to approach to each other and oscillate so as to be separated from each other.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a work machine. [Background technology]

[0002] Patent Document 1 discloses a working machine. The working machine includes a housing and a working member that is supported by the housing so as to be able to swing and that is at least partially disposed outside the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2013 / 0098644 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned working machine, when the working member swings, the housing vibrates. In this specification, a technique is provided that can reduce the vibration of the housing caused by the swinging of the working member. [Means for solving the problem]

[0005] This specification discloses a working machine. The working machine includes a housing, a working member that is swingably supported by the housing and at least partially disposed outside the housing, and a counterweight that is disposed inside the housing and swings when the working member swings. The working member and the counterweight swing toward each other and swing away from each other.

[0006] According to the above-mentioned configuration, the vibration of the housing caused by the swinging of the working member can be offset by the vibration of the housing caused by the swinging of the counterweight, thereby reducing the vibration of the housing. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of a working machine 2 according to an embodiment. [Diagram 2] 2 is an exploded perspective view of the vicinity of a rear end unit 8 in the working machine 2 of the embodiment. FIG. [Diagram 3] 1 is a perspective view of the vicinity of a front end unit 10 in a working machine 2 of an embodiment. [Figure 4] 2 is a cross-sectional view of a front end unit 10 in the working machine 2 of the embodiment. [Diagram 5] FIG. 2 is a side view of the working machine 2 of the embodiment with the front right housing 42 removed. [Figure 6] FIG. 2 is an exploded perspective view of a transmission mechanism 90, a blade 86, and a counterweight 88 according to the embodiment. [Figure 7] FIG. 2 is an exploded perspective view of a transmission mechanism 90, a blade 86, and a counterweight 88 according to the embodiment. [Figure 8] FIG. 2 is a side view of the working machine 2 of the embodiment with the left cover 46 removed. [Figure 9] 2 is a cross-sectional view of a front end unit 10 in the working machine 2 of the embodiment. [Figure 10] 2 is a cross-sectional view of a front end unit 10 in the working machine 2 of the embodiment. [Figure 11] FIG. 2 is a front view of the transmission mechanism 90, the blade 86, and the counterweight 88 of the embodiment. [Figure 12] FIG. 2 is a side view of the working machine 2 of the embodiment with the left cover 46 removed. [Figure 13] FIG. 2 is a side view of the working machine 2 of the embodiment with the front right housing 42 removed. [Figure 14] 1 is an exploded perspective view of a first transmission unit 78, a first output shaft 82, a blade 86, and an adjustment member 160 according to the embodiment. FIG. [Figure 15] 1 is an exploded perspective view of a first transmission unit 78, a first output shaft 82, a blade 86, and an adjustment member 160 according to the embodiment. FIG. [Figure 16]2 is an exploded perspective view of a first output shaft 82 and a first adjustment member 170 according to the embodiment. FIG. [Figure 17] 1 is a cross-sectional view of a first output shaft 82, a blade 86, and a first adjustment member 170 according to the embodiment. [Figure 18] 4 is a cross-sectional view of a first output shaft 82 and a first adjustment member 170 in the embodiment. FIG. [Figure 19] 2 is an exploded perspective view of a first output shaft 82 and a second adjustment member 172 according to the embodiment. FIG. [Figure 20] 4 is a cross-sectional view of a first output shaft 82, a blade 86, and a second adjustment member 172 in the embodiment. FIG. [Figure 21] 1 is a perspective view of a right mounting portion 120 of the blade 86 according to the embodiment. FIG. [Figure 22] 1 is a perspective view of a left mounting portion 124 of the blade 86 according to the embodiment. [Figure 23] 2 is a perspective view of the front end unit 10 and its vicinity in a state in which a blade cover 300 is attached to a blade portion 116 in the work machine 2 of the embodiment. FIG. [Figure 24] FIG. 2 is a cross-sectional view of the blade 86 and blade cover 300 of the embodiment, showing a state in which the blade cover 300 is attached to the blade 86. [Diagram 25] FIG. 2 is a front cross-sectional view of the blade 86 and blade cover 300 according to the embodiment, in which the blade cover 300 is attached to the blade 86. [Figure 26] FIG. 2 is a cross-sectional view of the blade 86 and blade cover 300 of the embodiment before the blade cover 300 is attached to the blade 86. [Figure 27] 1 is a front view of the vicinity of the front end unit 10 in the process of attaching the blade cover 300 to the blade 86 in the working machine 2 of the embodiment. [Figure 28] 2 is a cross-sectional view of the working machine 2 according to the embodiment before the blade cover 300 is attached to the pole 4. FIG. [Figure 29] 2 is a cross-sectional view of the working machine 2 according to the embodiment in a state where a blade cover 300 is attached to a pole 4. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Representative and non-limiting examples of the present invention are described in detail below with reference to the drawings. This detailed description is intended simply to provide those skilled in the art with details for implementing the preferred examples of the present invention, and is not intended to limit the scope of the present invention. Additionally, the additional features and inventions disclosed can be used separately or together with other features and inventions to provide further improved work machines, methods of making and using the same.

[0009] In addition, the combinations of features and steps disclosed in the following detailed description are not essential for implementing the present invention in the broadest sense, but are specifically described only to illustrate representative embodiments of the present invention. Furthermore, the various features of the following representative embodiments and the various features described in the claims do not have to be combined in the exact manner of the embodiments described herein or in the order listed in order to provide additional and useful embodiments of the present invention.

[0010] All features described in the specification and / or claims are intended to be disclosed individually and independently of one another as limitations to the specific features described in the original disclosure and claims, apart from the configuration of features described in the examples and / or claims. Furthermore, all numerical ranges and group or aggregate descriptions are intended to disclose intermediate configurations thereof as limitations to the specific features described in the original disclosure and claims.

[0011] In one or more embodiments, the work machine may further include a prime mover and a transmission mechanism disposed inside the housing. The transmission mechanism may include a rotating member that rotates about a rotation axis by operation of the prime mover, a first transmission unit attached to the rotating member and transmitting the rotation of the rotating member to the working member, and a second transmission unit attached to the rotating member and transmitting the rotation of the rotating member to the counterweight.

[0012] According to the above configuration, both the first transmission unit and the second transmission unit can be operated by the operation of one rotating member, which makes it possible to reduce the number of parts.

[0013] In one or more embodiments, the first transmission unit may include a first rod attached to the rotating member. The second transmission unit may include a second rod attached to the rotating member. When the implement is viewed along the rotation axis, the first rod may at least partially overlap the second rod.

[0014] In a configuration in which the first rod does not at least partially overlap with the second rod when the working machine is viewed along the rotation axis, the working machine becomes larger in size in a direction perpendicular to the rotation axis. According to the above configuration, since the first rod at least partially overlaps with the second rod when the working machine is viewed along the rotation axis, it is possible to prevent the working machine from becoming larger in size in the direction perpendicular to the rotation axis.

[0015] In one or more embodiments, the first transmission unit may further include a first spindle and a third rod movably attached to the first rod via the first spindle to transmit the movement of the first rod to the working member, and the second transmission unit may further include a second spindle and a fourth rod movably attached to the second rod via the second spindle to transmit the movement of the second rod to the counterweight.

[0016] According to the above configuration, since the first transmission unit includes the third rod, the position of the pivot shaft of the working member can be easily adjusted, and since the second transmission unit includes the fourth rod, the position of the pivot shaft of the counterweight can be easily adjusted.

[0017] In one or more embodiments, the work machine may further include a first output shaft connecting the first transmission unit and the working member and extending on the pivot axis of the working member, and a second output shaft connecting the second transmission unit and the counterweight and extending on the pivot axis of the counterweight.

[0018] According to the above configuration, the first output shaft allows the position of the working member to be easily adjusted relative to the first transmission unit in the direction in which the pivot shaft of the working member extends, and the second output shaft allows the position of the counterweight to be easily adjusted relative to the second transmission unit in the direction in which the pivot shaft of the counterweight extends.

[0019] In one or more embodiments, the distance between the rotation axis of the rotating member and the pivot axis of the working member may be substantially the same as the distance between the rotation axis of the rotating member and the pivot axis of the counterweight.

[0020] According to the above-mentioned configuration, the vibration of the housing caused by the swinging of the working member can be offset by the vibration of the housing caused by the swinging of the counterweight, thereby making it possible to further reduce the vibration of the housing.

[0021] In one or more embodiments, the working member may have a first location and a second location supported by the housing. The first location and the second location may be disposed on an axis of rotation of the working member. The counterweight may be disposed between the first location and the second location in a direction along the axis of rotation of the working member.

[0022] In a configuration in which the counterweight is not disposed between the first and second locations in the direction along the pivot axis of the working member, the working member may tilt due to the weight of the counterweight. According to the above configuration, the counterweight is disposed between the first and second locations in the direction along the pivot axis of the working member, so that the working member can be prevented from tilting due to the weight of the counterweight.

[0023] In one or more embodiments, the implement may further include a longitudinally extending pole secured to the housing, and a handle secured to the pole for being grasped by a user.

[0024] According to the above configuration, a user grips the handle to handle the pole-type working machine. If the housing vibrates due to the swinging of the working member, the vibration of the housing reduces the maneuverability of the pole-type working machine. According to the above configuration, the vibration of the housing caused by the swinging of the working member is offset by the vibration of the housing caused by the swinging of the counterweight, so that the maneuverability of the pole-type working machine can be prevented from being reduced.

[0025] In one or more embodiments, the work member may include a blade for digging into the earth.

[0026] According to the above configuration, the housing vibrates as the blade digs up the ground. Therefore, the housing is subjected to vibrations caused by the swinging of the blade and vibrations caused by the blade digging up the ground. This causes the housing to vibrate significantly. According to the above configuration, the vibrations of the housing caused by the swinging of the blade can be offset by the vibrations of the housing caused by the swinging of the counterweight. This makes it possible to reduce the vibrations of the housing.

[0027] (Example) As shown in Fig. 1, the work machine 2 is a pole-type work machine. The work machine 2 is a grass digger that digs up soil on the ground and removes grass. The work machine 2 includes a pole 4, a loop handle 6, a rear end unit 8, and a front end unit 10. A user handles the work machine 2 by holding the loop handle 6 with one hand and the rear end unit 8 with the other hand.

[0028] The pole 4 has a long and thin rod shape. The pole 4 includes a first pole 12 and a second pole 14. The first pole 12 is detachably attached to the second pole 14. The loop handle 6 is fixed to the first pole 12. Hereinafter, the direction in which the pole 4 extends is referred to as the front-rear direction, the direction perpendicular to the front-rear direction is referred to as the left-right direction, and the direction perpendicular to the front-rear direction and the left-right direction is referred to as the up-down direction.

[0029] The rear end unit 8 is fixed near the rear end of the pole 4. As shown in Fig. 2, the rear end unit 8 includes a rear end housing 16, a motor housing 18, a motor 20, a trigger 22, a shark fin 24, and a battery pack BP.

[0030] The rear end housing 16 includes a rear end right housing 28 that defines the outer shape of the right half of the rear end housing 16, and a rear end left housing 30 that defines the outer shape of the left half of the rear end housing 16. The rear end housing 16 includes a motor accommodating portion 32, a grip portion 34, and a switch accommodating portion 36.

[0031] A battery pack BP is detachably attached to the rear surface of the motor housing 32. The battery pack BP includes a rechargeable secondary battery, for example, a lithium ion battery. The grip 34 is gripped by a user when the work machine 2 is used for work.

[0032] The motor housing 18 and the motor 20 are disposed inside the motor accommodating portion 32. The motor 20 is disposed inside the motor housing 18. In FIG. 2, the motor 20 is illustrated by a dashed line. The motor 20 is an example of a prime mover. The motor 20 is, for example, a brushless motor. When the motor 20 rotates, the transmission shaft 38 rotates about an axis extending in the front-rear direction. In FIG. 2, the transmission shaft 38 is illustrated by a dashed line. The transmission shaft 38 is rotatably supported by the pole 4 inside the pole 4.

[0033] The trigger 22 is attached to the lower part of the switch housing part 36 so as to be able to be pressed into it. The shark fin 24 is attached to the upper part of the grip part 34 so as to be able to be pressed into it. When the shark fin 24 is pressed into it, the trigger 22 becomes pressable. When the shark fin 24 is pressed into it by the palm of a user holding the grip part 34 and the trigger 22 is pressed into it by the fingers of the user holding the grip part 34, the motor 20 rotates.

[0034] As shown in FIG. 3, the front end unit 10 is fixed to the front end of the pole 4. The front end unit 10 is an example of a blade unit. The front end unit 10 includes a front end housing 40. The front end housing 40 includes a front end right housing 42, a front end left housing 44, and a left cover 46. The front end right housing 42 defines the outer shape of the right portion of the front end housing 40. The front end left housing 44 and the left cover 46 define the outer shape of the left portion of the front end housing 40.

[0035] The front-end left housing 44 includes a main portion 48 and a sub portion 50. The main portion 48 is fixed to the front-end right housing 42. The pole 4 is sandwiched between the main portion 48 and the front-end right housing 42. As shown in FIG. 4, the main portion 48 and the front-end right housing 42 define a right housing space 52. The main portion 48 includes a partition wall 54, and the sub portion 50 protrudes leftward from the partition wall 54. The sub portion 50 is fixed to the left cover 46. The sub portion 50, the left cover 46, and the partition wall 54 define a rod housing space 56. The partition wall 54 divides the internal space of the front-end housing 40 into the right housing space 52 and the rod housing space 56.

[0036] The front-end housing 40 further includes a warm cover 58. The warm cover 58 is fixed to the partition 54 from the right side of the partition 54. The warm cover 58 covers a portion of the partition 54. The warm cover 58 divides the right accommodating space 52 into a warm accommodating space 60 and a weight accommodating space 62. The warm accommodating space 60 is defined by the partition 54 and the inner surface of the warm cover 58. The weight accommodating space 62 is defined by the front-end right housing 42, the main portion 48, and the outer surface of the warm cover 58.

[0037] The front end unit 10 further includes a worm 64, a worm wheel 66, and a rotating shaft 68. The worm 64 and the worm wheel 66 are disposed in the worm accommodating space 60. As shown in FIG. 5, the worm 64 is fixed to the outer circumferential surface of the front end of the transmission shaft 38. The transmission shaft 38 is rotatably supported by the front end housing 40 through bearings 69a and 69b, and the worm 64 is disposed between the bearings 69a and 69b. The worm wheel 66 meshes with the worm 64. When the worm 64 rotates together with the transmission shaft 38 about an axis extending in the front-rear direction, the worm wheel 66 rotates about a rotation axis AX1 extending in the left-right direction. The rotation speed of the worm wheel 66 is smaller than the rotation speed of the worm 64. Therefore, the worm 64 and the worm wheel 66 function as a reduction mechanism.

[0038] As shown in FIG. 4 , the rotating shaft 68 is inserted into the worm wheel 66. The rotating shaft 68 is disposed inside the front end housing 40. The rotating shaft 68 is rotatably supported by the front end right housing 42 via a bearing 70. The rotating shaft 68 is also rotatably supported by the partition wall 54 via a bearing 72. The rotating shaft 68 rotates together with the worm wheel 66 about the rotation axis AX1. The rotating shaft 68 is inserted into the opening of the worm cover 58 and the opening of the partition wall 54. The vicinity of the left end of the rotating shaft 68 is disposed in the rod accommodating space 56.

[0039] As shown in Figures 6 and 7, the front end unit 10 includes a disk 76, a first transmission unit 78, a second transmission unit 80, a first output shaft 82, a second output shaft 84, a blade 86, and a counterweight 88. As shown in Figure 8, the disk 76 (see Figure 4), the first transmission unit 78, and the second transmission unit 80 are disposed in the rod accommodating space 56. Hereinafter, the rotating shaft 68, the disk 76, the first transmission unit 78, and the second transmission unit 80 may be collectively referred to as a transmission mechanism 90. In addition, the rotating shaft 68 and the disk 76 may be collectively referred to as a rotating member 91.

[0040] 6 and 7, the disk 76 has a shaft insertion hole 92 penetrating the disk 76 in the left-right direction. The left end of the rotating shaft 68 is inserted into the shaft insertion hole 92. The disk 76 is sandwiched between a pair of fixing plates 93a, 93b. As a result, the disk 76 is fixed to the left end of the rotating shaft 68. The disk 76 rotates together with the rotating shaft 68 about the rotation axis AX1.

[0041] The disk 76 includes a center plate portion 94, a right disk portion 96, and a left disk portion 98. The center plate portion 94 has a disk shape. The right disk portion 96 is disposed on the right surface of the center plate portion 94. The left disk portion 98 is disposed on the left surface of the center plate portion 94. When the disk 76 is viewed along the rotation axis AX1, the left disk portion 98 at least partially overlaps with the right disk portion 96. The outer peripheral surface of the right disk portion 96 and the outer peripheral surface of the left disk portion 98 have a circular shape. The central axis of the outer peripheral surface of the right disk portion 96 and the central axis of the outer peripheral surface of the left disk portion 98 are offset from the central axis of the shaft insertion hole 92, i.e., the rotation axis AX1. Around the central axis of the shaft insertion hole 92, the central axis of the outer peripheral surface of the right disk portion 96 is disposed at a position of 0 degrees, and the central axis of the outer peripheral surface of the left disk portion 98 is disposed at a position of 180 degrees. When the central plate portion 94 rotates, the right disc portion 96 and the left disc portion 98 rotate about the rotation axis AX1. The phase of the rotation period of the right disc portion 96 is out of phase with the phase of the rotation period of the left disc portion 98 by 180 degrees.

[0042] The first transmission unit 78 is attached to the right disc portion 96. The first transmission unit 78 is attached to the blade 86 via the first output shaft 82. The first transmission unit 78 includes a first rod 100, a first connecting spindle 102, and a second rod 104.

[0043] The first rod 100 includes a first mounting portion 106 and a first arm portion 108. The first mounting portion 106 has a first disk insertion hole 110 penetrating the first mounting portion 106 in the left-right direction. The right disk portion 96 is inserted into the first disk insertion hole 110 via a bearing. The first mounting portion 106 is disposed between the center plate portion 94 and the fixed plate 93a. When the transmission mechanism 90 is viewed along the rotation axis AX1, the first mounting portion 106 at least partially overlaps with the center plate portion 94. The first arm portion 108 protrudes from the first mounting portion 106.

[0044] The first connecting spindle 102 is inserted into the tip of the first arm portion 108. The first connecting spindle 102 is inserted into one end of the second rod 104. The first connecting spindle 102 extends in the left-right direction.

[0045] One end of the second rod 104 is attached to a first arm portion 108 via a first connecting spindle 102. The second rod 104 is attached to the first arm portion 108 so as to be movable (rotatable) relative to the first rod 100. When the first transmission unit 78 is viewed along the rotation axis AX1, the first arm portion 108 at least partially overlaps with the second rod 104.

[0046] The first output shaft 82 is inserted into the other end of the second rod 104. The first output shaft 82 is fixed to the other end of the second rod 104. The first output shaft 82 connects the other end of the second rod 104 and the blade 86. The first output shaft 82 extends in the left-right direction. The center axis AX2 of the first output shaft 82 extends in the left-right direction. The center axis AX2 is disposed forward of the rotation axis AX1. As shown in FIG. 9, the center axis AX2 is substantially parallel to the rotation axis AX1. The first output shaft 82 is rotatably supported by the front end housing 40 via bearings 112a and 112b. Both ends of the first output shaft 82 are disposed outside the front end housing 40.

[0047] The blade 86 is attached to the first output shaft 82. The blade 86 moves together with the first output shaft 82. The blade 86 is an example of a working member. The blade 86 is made of, for example, a metal material. The blade 86 is disposed outside the front end housing 40. In a modified example, a part of the blade 86 may be disposed outside the front end housing 40. The blade 86 is supported by the front end housing 40 via the first output shaft 82. As shown in FIG. 6 and FIG. 7, the blade 86 includes a blade portion 116, a right connecting portion 118, a right mounting portion 120, a left connecting portion 122, and a left mounting portion 124.

[0048] The blade portion 116 has a generally flat plate shape extending in the left-right direction and the front-rear direction. The blade portion 116 has a longitudinal direction in the left-right direction. A plurality of cutting edges 116a are formed at each of the front end and the rear end of the blade portion 116. The plurality of cutting edges 116a are arranged side by side in the left-right direction at each of the front end and the rear end of the blade portion 116.

[0049] One end of the right connection part 118 is connected to the right end of the blade part 116. The right connection part 118 extends upward from the right end of the blade part 116, then bends to extend leftward, and further bends to extend upward. The right attachment part 120 is connected to the other end of the right connection part 118. As shown in FIG. 9, the right attachment part 120 and the other end of the right connection part 118 are attached to the right end of the first output shaft 82 by a bolt 126. Hereinafter, the other end of the right attachment part 120 and the right connection part 118 may be referred to as a first point 128. The first point 128 is supported by the front end housing 40 via the first output shaft 82. The first point 128 is disposed on the central axis AX2.

[0050] As shown in FIG. 6 and FIG. 7, one end of the left connection part 122 is connected to the left end of the blade part 116. The left connection part 122 extends upward from the left end of the blade part 116, then bends and extends to the right, and then bends and extends upward. The left attachment part 124 is connected to the other end of the left connection part 122. As shown in FIG. 9, the left attachment part 124 and the other end of the left connection part 122 are attached to the left end of the first output shaft 82 by a bolt 130. Hereinafter, the left attachment part 124 and the other end of the left connection part 122 may be referred to as a second point 132. The second point 132 is supported by the front end housing 40 via the first output shaft 82. The second point 132 is disposed on the central axis AX2.

[0051] 6 and 7, the second transmission unit 80 is attached to the left disc portion 98. The second transmission unit 80 is attached to the counterweight 88 via the second output shaft 84. The second transmission unit 80 includes a third rod 136, a second connecting spindle 138, and a fourth rod 140.

[0052] The shape of the third rod 136 is substantially the same as that of the first rod 100. The third rod 136 includes a third mounting portion 142 and a third arm portion 144. The third mounting portion 142 has a third disk insertion hole 146 penetrating the third mounting portion 142 in the left-right direction. The left disk portion 98 is inserted into the third disk insertion hole 146 via a bearing. The third mounting portion 142 is disposed between the center plate portion 94 and the fixed plate 93b. When the transmission mechanism 90 is viewed along the rotation axis AX1, the third mounting portion 142 at least partially overlaps with each of the center plate portion 94 and the first mounting portion 106. The length of the third arm portion 144 is substantially the same as the length of the first arm portion 108.

[0053] The shape of the second connecting spindle 138 is substantially the same as the shape of the first connecting spindle 102. The second connecting spindle 138 is inserted into the tip of the third arm portion 144. The second connecting spindle 138 is inserted into one end of the fourth rod 140. The second connecting spindle 138 extends in the left-right direction.

[0054] The shape of the fourth rod 140 is substantially the same as the shape of the second rod 104. Therefore, the length of the fourth rod 140 is substantially the same as the length of the second rod 104. One end of the fourth rod 140 is attached to the third arm portion 144 via the second connection spindle 138. The fourth rod 140 is attached to the third arm portion 144 so as to be movable (rotatable) relative to the third rod 136. When the second transmission unit 80 is viewed along the left-right direction, the third arm portion 144 at least partially overlaps with the fourth rod 140.

[0055] As shown in FIG. 10, the second output shaft 84 is inserted into the other end of the fourth rod 140. The second output shaft 84 is fixed to the other end of the fourth rod 140. The second output shaft 84 connects the other end of the fourth rod 140 and the counterweight 88. The second output shaft 84 extends in the left-right direction. The center axis AX3 of the second output shaft 84 extends in the left-right direction. As shown in FIG. 5, the center axis AX3 is disposed forward of the rotation axis AX1 and the center axis AX2. The center axis AX3 is substantially parallel to each of the rotation axis AX1 and the center axis AX2. The distance between the rotation axis AX1 and the center axis AX3 is substantially the same as the distance between the rotation axis AX1 and the center axis AX2. As shown in FIG. 10, the second output shaft 84 is rotatably supported by the front end housing 40 via bearings 148a and 148b. The second output shaft 84 is disposed inside the front end housing 40.

[0056] The counterweight 88 is fixed to the second output shaft 84. The counterweight 88 is made of, for example, a metal material. The counterweight 88 has a substantially T-shape. The weight of the counterweight 88 is greater than the weight of the blade 86. The counterweight 88 includes a first extension portion 152 extending from the second output shaft 84 and a second extension portion 154 extending leftward and rightward from the tip of the first extension portion 152. As shown in FIG. 5, the distance between the central axis AX3 and the second extension portion 154 is shorter than the distance between the central axis AX2 and the blade portion 116 of the blade 86. As shown in FIG. 11, the counterweight 88 is disposed between the first location 128 and the second location 132 of the blade 86 in the left-right direction. In the left-right direction, the position of the center of the counterweight 88 in the left-right direction is substantially the same as the position of the center of the blade 86 in the left-right direction.

[0057] As shown in FIG. 8 and FIG. 12, when the rotating shaft 68 rotates around the rotation axis AX1, the disk 76 rotates around the rotation axis AX1. As a result, the right disk portion 96 (see FIG. 7) and the left disk portion 98 (see FIG. 7) rotate around the rotation axis AX1. As the right disk portion 96 rotates, the first arm portion 108 moves, and the first connecting spindle 102 reciprocates between the first position (see FIG. 8) and the second position (see FIG. 12). As a result, the second rod 104 swings around the central axis AX2, and the first output shaft 82 rotates around the central axis AX2. When the first connecting spindle 102 moves from the first position to the second position, the first output shaft 82 moves in the first direction D1 (see FIG. 8) around the central axis AX2, and when the first connecting spindle 102 moves from the second position to the first position, the first output shaft 82 moves in the second direction D2 (see FIG. 12) around the central axis AX2. The first direction D1 is opposite to the second direction D2. As a result, the blade 86 swings around the central axis AX2. The central axis AX2 corresponds to the swing axis of the blade 86. When the blade 86 comes into contact with the ground while swinging, the blade 86 digs up the soil on the ground. As a result, the grass growing on the ground is removed from the ground.

[0058] In addition, with the rotation of the left disk portion 98, the third arm portion 144 moves, and the second connecting spindle 138 reciprocates between the third position (see FIG. 8) and the fourth position (see FIG. 12). As a result, the fourth rod 140 swings about the central axis AX3, and the second output shaft 84 rotates about the central axis AX3. The rotation speed of the second output shaft 84 is substantially the same as the rotation speed of the first output shaft 82. When the second connecting spindle 138 moves from the third position to the fourth position, the second output shaft 84 moves in the third direction D3 (see FIG. 8) about the central axis AX3, and when the second connecting spindle 138 moves from the fourth position to the third position, the second output shaft 84 moves in the fourth direction D4 (see FIG. 12) about the central axis AX3. The third direction D3 is the opposite direction to the first direction D1. The fourth direction D4 is opposite to each of the third direction D3 and the second direction D2. As shown in FIG. 5 and FIG. 13, the counterweight 88 swings around the central axis AX3. The central axis AX3 corresponds to the swing axis of the counterweight 88. When the front end unit 10 is viewed from the right side, when the blade 86 swings in the clockwise direction (first direction D1), the counterweight 88 swings in the counterclockwise direction (third direction D3). When the blade 86 swings in the counterclockwise direction (second direction D2), the counterweight 88 swings in the clockwise direction (fourth direction D4). That is, when the blade 86 swings to approach the counterweight 88, the counterweight 88 swings to approach the blade 86, and when the blade 86 swings to move away from the counterweight 88, the counterweight 88 swings to move away from the blade 86. Therefore, the vibration of the front end housing 40 caused by the swinging of the blade 86 is offset by the vibration of the front end housing 40 caused by the swinging of the counterweight 88 .

[0059] In this embodiment, the blade 86 is attached to the first output shaft 82 so that the mounting posture of the blade 86 relative to the front end housing 40 is adjustable. As shown in Figs. 14 and 15, the front end unit 10 includes two adjust members 160. The adjust members 160 are detachably attached to the first output shaft 82. The adjust members 160 are made of, for example, a metal material. In a modified example, the adjust members 160 may be made of a resin material. Hereinafter, one adjust member 160 may be referred to as a first adjust member 170, and the other adjust member 160 may be referred to as a second adjust member 172. The shape of the first adjust member 170 is substantially the same as the shape of the second adjust member 172.

[0060] As shown in FIG. 16, the adjust member 160 includes a base portion 174, an attachment portion 176, and an adjustment portion 178. The base portion 174 has a generally circular plate shape. The base portion 174 has an outer peripheral surface 174a, a first side surface 174b, and a second side surface 174c. The outer peripheral surface 174a has a circular shape. A circle center 174d of the outer peripheral surface 174a is disposed on the central axis AX2. The outer peripheral surface 174a connects the periphery of the first side surface 174b and the periphery of the second side surface 174c. The first side surface 174b is the surface opposite to the second side surface 174c.

[0061] The mounting portion 176 is a through hole. The cross section of the mounting portion 176 has a substantially circular shape, with a number of straight lines at various points. The mounting portion 176 penetrates the base portion 174 in the left-right direction from the first side surface 174b to the second side surface 174c. As shown in FIG. 17, the center of the cross section of the mounting portion 176 is located on the circle center 174d of the outer circumferential surface 174a of the base portion 174, i.e., on the central axis AX2. The mounting portion 176 includes a circular arc portion 179 and a positioning portion 180.

[0062] The arc portion 179 includes a first arc portion 182, a second arc portion 184, and a third arc portion 186. The first arc portion 182, the second arc portion 184, and the third arc portion 186 are disposed apart from each other. The first arc portion 182, the second arc portion 184, and the third arc portion 186 have the same circle center 174d. The length of the first arc portion 182 is longer than the length of the second arc portion 184 and the length of the third arc portion 186. The length of the second arc portion 184 is approximately the same as the length of the third arc portion 186.

[0063] The positioning portion 180 includes a first flat portion 190, a second flat portion 192, and a third flat portion 194. The first flat portion 190, the second flat portion 192, and the third flat portion 194 have a planar shape. The first flat portion 190 is connected to one end of the first arc portion 182 and one end of the second arc portion 184. The second flat portion 192 is connected to the other end of the second arc portion 184 and one end of the third arc portion 186. The third flat portion 194 is connected to the other end of the third arc portion 186 and the other end of the first arc portion 182.

[0064] The first flat portion 190, the second flat portion 192, and the third flat portion 194 are disposed apart from each other. Around the circle center 174d, the angle (90 degrees) between the first flat portion 190 and the second flat portion 192 is substantially the same as the angle (90 degrees) between the second flat portion 192 and the third flat portion 194. The first flat portion 190 is substantially parallel to the third flat portion 194. The second flat portion 192 is inclined at 90 degrees with respect to each of the first flat portion 190 and the third flat portion 194. The length of the first flat portion 190 around the circle center 174d is substantially the same as the length of the second flat portion 192 around the circle center 174d and the length of the third flat portion 194 around the circle center 174d.

[0065] As shown in FIG. 16, the adjustment portion 178 is disposed on the outer circumferential surface 174a of the base 174. The adjustment portion 178 has a plurality of (seven in this embodiment) receiving grooves 198. The cross section of the receiving grooves 198 has a substantially trapezoidal shape. The receiving grooves 198 are recessed radially inward of the base 174 from the outer circumferential surface 174a of the base 174 toward the circular center 174d. The receiving grooves 198 are connected to the first side surface 174b of the base 174. The receiving grooves 198 are not connected to the second side surface 174c of the base 174.

[0066] The multiple receiving grooves 198 are arranged side by side at equal intervals around the central axis AX2. Adjacent receiving grooves 198 are spaced apart. The multiple receiving grooves 198 are arranged on a portion of the entire circumference of the outer circumferential surface 174a of the base 174 around the central axis AX2. The multiple receiving grooves 198 are arranged such that the interval between the receiving grooves 198 located at both ends of the multiple receiving grooves 198 is 160 degrees around the central axis AX2.

[0067] As shown in FIG. 18, the width W1 of the receiving groove 198 in the direction in which the central axis AX2 extends (left-right direction) is smaller than the distance between the first side surface 174b and the second side surface 174c, i.e., the width W2 of the base portion 174. The width W1 is 30% or more and 70% or less of the width W2. This can prevent both the strength of the protrusion between the adjacent receiving grooves 198 and the strength of the entire adjusting member 160 from being excessively reduced. The width W1 may be 40% or more and 60% or less of the width W2. This can further prevent both the strength of the protrusion between the adjacent receiving grooves 198 and the strength of the entire adjusting member 160 from being excessively reduced. In this embodiment, the width W1 is 50% of the width W2.

[0068] As shown in FIG. 16 and FIG. 19, the first output shaft 82 includes a central portion 202, a right plate attachment portion 204, and a left plate attachment portion 206. As shown in FIG. 16, the right plate attachment portion 204 is disposed on the right side of the central portion 202. The right plate attachment portion 204 is located near the right end of the first output shaft 82. The right plate attachment portion 204 is inserted into the attachment portion 176 of the first adjust member 170. The cross section of the outer surface of the right plate attachment portion 204 has a substantially circular shape, and has a shape in which a part of the circle is a straight line. The diameter of the outer surface of the right plate attachment portion 204 is smaller than the diameter of the outer surface of the central portion 202. Therefore, a right step portion 208 is formed at the boundary between the right plate attachment portion 204 and the central portion 202. The cross section of the right plate attachment portion 204 has a shape corresponding to the cross section of the attachment portion 176 of the adjust member 160. The right plate attachment portion 204 includes a right shaft arc portion 212 and a right shaft positioning portion 214 .

[0069] As shown in FIG. 17 , the right shaft arc portion 212 includes a first right shaft arc portion 216, a second right shaft arc portion 218, and a third right shaft arc portion 220. The first right shaft arc portion 216, the second right shaft arc portion 218, and the third right shaft arc portion 220 are arranged apart from each other. The length of the first right shaft arc portion 216 is approximately the same as the length of the first arc portion 182. The length of the second right shaft arc portion 218 is approximately the same as the length of the second arc portion 184. The length of the third right shaft arc portion 220 is approximately the same as the length of the third arc portion 186.

[0070] The right shaft positioning portion 214 includes a first right shaft planar portion 222, a second right shaft planar portion 224, and a third right shaft planar portion 226. The first right shaft planar portion 222, the second right shaft planar portion 224, and the third right shaft planar portion 226 have a planar shape. The first right shaft planar portion 222 is connected to one end of the first right shaft arc portion 216 and one end of the second right shaft arc portion 218. The second right shaft planar portion 224 is connected to the other end of the second right shaft arc portion 218 and one end of the third right shaft arc portion 220. The third right shaft planar portion 226 is connected to the other end of the third right shaft arc portion 220 and the other end of the first right shaft arc portion 216.

[0071] The angle between the first right shaft planar portion 222 and the second right shaft planar portion 224 is approximately the same as the angle between the first planar portion 190 and the second planar portion 192. The angle between the second right shaft planar portion 224 and the third right shaft planar portion 226 is approximately the same as the angle between the second planar portion 192 and the third planar portion 194. The first right shaft planar portion 222 is approximately parallel to the third right shaft planar portion 226. The second right shaft planar portion 224 is inclined by 90 degrees with respect to each of the first right shaft planar portion 222 and the third right shaft planar portion 226. The length of the first right shaft planar portion 222 around the central axis AX2 is approximately the same as the length of the first planar portion 190 around the circle center 174d. The length of the second right shaft planar portion 224 around the central axis AX2 is approximately the same as the length of the second planar portion 192 around the circle center 174d. The length of the third right shaft flat portion 226 about the central axis AX2 is approximately the same as the length of the third flat portion 194 about the circle center 174d.

[0072] When the right plate mounting portion 204 is inserted into the mounting portion 176 of the first adjust member 170, the first right shaft arc portion 216 is disposed opposite the first arc portion 182. The second right shaft arc portion 218 is disposed opposite the second arc portion 184. The third right shaft arc portion 220 is disposed opposite the third arc portion 186. The first right shaft flat portion 222 is disposed opposite the first flat portion 190. The second right shaft flat portion 224 is disposed opposite the second flat portion 192. The third right shaft flat portion 226 is disposed opposite the third flat portion 194. By disposing the right shaft positioning portion 214 at a specific position relative to the positioning portion 180, the first adjust member 170 is attached to the right plate mounting portion 204 in a specific posture. In addition, erroneous assembly of the first adjust member 170 to the right plate mounting portion 204 can be suppressed.

[0073] Moreover, the first right shaft flat portion 222 abuts against the first flat portion 190. The second right shaft flat portion 224 abuts against the second flat portion 192. The third right shaft flat portion 226 abuts against the third flat portion 194. When a force about the central axis AX2 is applied to the first adjust member 170 or the right plate attachment portion 204, the first right shaft flat portion 222 is pressed against the first flat portion 190, the second right shaft flat portion 224 is pressed against the second flat portion 192, and the third right shaft flat portion 226 is pressed against the third flat portion 194. This prevents the first adjust member 170 from rotating about the central axis AX2 relative to the right plate attachment portion 204.

[0074] As shown in FIG. 19, the left plate attachment portion 206 is disposed on the left side of the central portion 202. The left plate attachment portion 206 is located near the left end of the first output shaft 82. The left plate attachment portion 206 is inserted into the attachment portion 176 of the second adjust member 172. The cross section of the outer surface of the left plate attachment portion 206 has a substantially circular shape, and has a shape in which a part of the circle is a straight line. The diameter of the outer surface of the left plate attachment portion 206 is smaller than the diameter of the outer surface of the central portion 202. Therefore, a left step portion 230 is formed at the boundary between the left plate attachment portion 206 and the central portion 202. The cross section of the left plate attachment portion 206 has a shape corresponding to the cross section of the attachment portion 176 of the adjust member 160. In addition, the cross section of the left plate attachment portion 206 is plane-symmetrical to the cross section of the right plate attachment portion 204 with respect to a plane perpendicular to the central axis AX2. That is, the left plate attachment portion 206 includes a left shaft arc portion 232 and a left shaft positioning portion 234. Also, as shown in Fig. 20, the left shaft arc portion 232 includes a first left shaft arc portion 236, a second left shaft arc portion 238, and a third left shaft arc portion 240. Furthermore, the left shaft positioning portion 234 includes a first left shaft flat portion 242, a second left shaft flat portion 244, and a third left shaft flat portion 246.

[0075] When the left plate mounting portion 206 is inserted into the mounting portion 176 of the second adjust member 172, the first left shaft arc portion 236 is disposed opposite the first arc portion 182. The second left shaft arc portion 238 is disposed opposite the second arc portion 184. The third left shaft arc portion 240 is disposed opposite the third arc portion 186. The first left shaft flat portion 242 is disposed opposite the first flat portion 190. The second left shaft flat portion 244 is disposed opposite the second flat portion 192. The third left shaft flat portion 246 is disposed opposite the third flat portion 194. By disposing the left shaft positioning portion 234 at a specific position relative to the positioning portion 180, the second adjust member 172 is attached to the left plate mounting portion 206 in a specific posture. In addition, erroneous assembly of the second adjust member 172 to the left plate mounting portion 206 can be suppressed.

[0076] Moreover, the first left shaft planar portion 242 abuts against the first planar portion 190. The second left shaft planar portion 244 abuts against the second planar portion 192. The third left shaft planar portion 246 abuts against the third planar portion 194. When a force about the central axis AX2 is applied to the second adjust member 172 or the left plate attachment portion 206, the first planar portion 190 is pressed against the first left shaft planar portion 242, the second planar portion 192 is pressed against the second left shaft planar portion 244, and the third planar portion 194 is pressed against the third left shaft planar portion 246. This prevents the second adjust member 172 from rotating about the central axis AX2 relative to the left plate attachment portion 206.

[0077] In addition, the cross-sectional shape of the left plate attachment portion 206 is symmetrical with respect to a plane perpendicular to the central axis AX2 as the cross-sectional shape of the right plate attachment portion 204. Therefore, the attachment posture of the first adjust member 170 relative to the first output shaft 82 is substantially the same as the attachment posture of the second adjust member 172 relative to the first output shaft 82.

[0078] As shown in FIG. 21, the right attachment portion 120 of the blade 86 includes a right disc portion 250, a right peripheral wall portion 252, and a plurality of right protrusions 254 (five in this embodiment).

[0079] The right disc portion 250 has a substantially disc shape. The right disc portion 250 includes an outer peripheral surface 256, a first side surface 258, and a second side surface 260. The outer peripheral surface 256 has a circular shape. A circle center 256a of the outer peripheral surface 256 is disposed on the central axis AX2. The outer peripheral surface 256 connects the periphery of the first side surface 258 and the periphery of the second side surface 260. The first side surface 258 is the surface opposite to the second side surface 260. The right disc portion 250 has an insertion hole 262. The insertion hole 262 penetrates the right disc portion 250 in the left-right direction from the first side surface 258 to the second side surface 260. The center of the cross section of the insertion hole 262 is disposed on the circle center 256a of the outer peripheral surface 256. The right plate attachment portion 204 (see FIG. 9) is inserted into the insertion hole 262. At this time, the first side surface 258 faces the first side surface 174b of the first adjust member 170 (see FIG. 16).

[0080] The right peripheral wall portion 252 protrudes leftward from the peripheral edge of the first side surface 258. The right peripheral wall portion 252 goes around the peripheral edge of the first side surface 258. The right peripheral wall portion 252 has a generally cylindrical shape.

[0081] The right protrusion 254 has a generally trapezoidal shape. The right protrusion 254 protrudes radially inward of the right circular plate portion 250 toward the central axis AX2 from the inner circumferential surface of the right peripheral wall portion 252. The right protrusion 254 is connected to the first side surface 258.

[0082] The right protrusions 254 are arranged at equal intervals around the central axis AX2. Adjacent right protrusions 254 are spaced apart. The right protrusions 254 are arranged on a portion of the entire circumference of the inner circumferential surface of the right peripheral wall portion 252 around the central axis AX2. As shown in FIG. 17, the interval between adjacent right protrusions 254 around the central axis AX2 is approximately the same as the interval between adjacent receiving grooves 198 around the central axis AX2. The right protrusions 254 are received in the receiving grooves 198. At this time, the first adjust member 170 is arranged inside the right peripheral wall portion 252. The number of the right protrusions 254 is smaller than the number of the receiving grooves 198. Therefore, by changing the arrangement of the right protrusions 254 relative to the receiving grooves 198, the mounting attitude of the right mounting portion 120 relative to the first adjust member 170 is adjusted.

[0083] As shown in FIG. 9, the right mounting portion 120 is attached to the first adjust member 170 from the right side. The other ends of the right mounting portion 120, the first adjust member 170, and the right connection portion 118 are sandwiched between the bolt 126 and the right step portion 208 outside the front end housing 40. This fixes the mounting attitude of the right mounting portion 120 relative to the first adjust member 170. In addition, the bolt 126 abuts against the right mounting portion 120, the first adjust member 170, and the other ends of the right connection portion 118. This prevents the right mounting portion 120, the first adjust member 170, and the other ends of the right connection portion 118 from coming out of the right plate mounting portion 204.

[0084] As shown in FIG. 22, the shape of the left mounting portion 124 of the blade 86 is symmetrical with respect to the right mounting portion 120 of the blade 86 with respect to a plane perpendicular to the central axis AX2. That is, the left mounting portion 124 includes a left disc portion 270, a left peripheral wall portion 272, and a plurality of (five in this embodiment) left protrusions 274. The number of the plurality of left protrusions 274 is the same as the number of the plurality of right protrusions 254 (see FIG. 21). The left disc portion 270 includes an outer peripheral surface 276, a first side surface 278, and a second side surface 280. The left disc portion 270 has an insertion hole 282. The center of the cross section of the insertion hole 282 is located on the circle center 276a of the outer peripheral surface 276. As shown in FIG. 20, the left protrusion 274 is received in the receiving groove 198. Therefore, by changing the arrangement of the multiple left protrusions 274 relative to the multiple receiving grooves 198, the mounting attitude of the left mounting portion 124 relative to the second adjust member 172 can be adjusted.

[0085] As shown in FIG. 9, the left mounting portion 124 is attached to the second adjust member 172 from the left side. The other ends of the left mounting portion 124, the second adjust member 172, and the left connecting portion 122 are sandwiched between the bolt 130 and the left step portion 230 outside the front end housing 40. This fixes the mounting attitude of the left mounting portion 124 relative to the second adjust member 172. In addition, the bolt 130 abuts against the left mounting portion 124, the second adjust member 172, and the other ends of the left connecting portion 122. This prevents the left mounting portion 124, the second adjust member 172, and the other ends of the left connecting portion 122 from coming out of the left plate mounting portion 206.

[0086] As shown in FIG. 23, the working machine 2 further includes a blade cover 300. The blade cover 300 is made of a resin material. The blade cover 300 is attached to the blade 86. The blade cover 300 covers the blade portion 116 of the blade 86. This prevents the blade portion 116 from coming into contact with the user, for example, when the working machine 2 is stored or transported. The blade cover 300 is also disposed away from the front end housing 40. In the following, the coordinate system is changed to the following coordinate system for explanation. Specifically, the longitudinal direction of the blade portion 116 is referred to as the left-right direction, the direction perpendicular to the left-right direction is referred to as the front-rear direction, and the direction extending in the left-right direction and the front-rear direction is referred to as the up-down direction. The blade portion 116 is disposed along a plane including the left-right direction and the front-rear direction.

[0087] The blade cover 300 extends in the left-right direction. The cross-sectional shape of the blade cover 300 is substantially the same in the left-right direction. For this reason, the blade cover 300 is manufactured by, for example, extrusion molding. As shown in FIG. 24, when the blade arbor 300 is attached to the blade portion 116, the lower surface of the blade portion 116 is substantially parallel to the ground G. The blade cover 300 includes a cover portion 302, an abutment portion 304, a guide portion 306, a release portion 308, and a frictional force applying portion 310.

[0088] The cover portion 302 covers the blade portion 116. The cover portion 302 includes a first cover portion 314 and a second cover portion 316. The first cover portion 314 is disposed forward of the second cover portion 316. The first cover portion 314 is disposed away from the second cover portion 316 in the front-rear direction. The first cover portion 314 and the second cover portion 316 are disposed opposite each other in the front-rear direction. The first cover portion 314 extends from the lower end toward the front upper side. The second cover portion 316 extends from the lower end toward the rear upper side. Therefore, the distance in the front-rear direction between the first cover portion 314 and the second cover portion 316 increases from the lower end toward the upper end. The maximum distance in the front-rear direction between the first cover portion 314 and the second cover portion 316 is longer than the length of the blade portion 116 in the front-rear direction. The first cover portion 314 covers the multiple cutting edges 116a at the front end of the blade portion 116. The second cover portion 316 covers the cutting edges 116 a at the rear end of the blade portion 116 .

[0089] The abutment portion 304 is disposed on the upper side of the blade portion 116. The abutment portion 304 includes a first abutment portion 320 and a second abutment portion 322. The first abutment portion 320 is disposed on the upper side of the cutting edges 116a at the front end of the blade portion 116. The second abutment portion 322 is disposed on the upper side of the cutting edges 116a at the rear end of the blade portion 116. The first abutment portion 320 is disposed forward of the second abutment portion 322. The first abutment portion 320 is connected to the upper end of the first cover portion 314. The second abutment portion 322 is connected to the upper end of the second cover portion 316. The first abutment portion 320 is disposed away from the second abutment portion 322 in the front-rear direction. The first abutment portion 320 is disposed opposite the second abutment portion 322 in the front-rear direction. The first abutment portion 320 extends from the lower end toward the rear upper side. The second contact portion 322 extends from the lower end toward the upper front side. Therefore, the distance between the first contact portion 320 and the second contact portion 322 in the front-rear direction decreases from the lower end toward the upper end. The minimum distance between the first contact portion 320 and the second contact portion 322 in the front-rear direction is shorter than the length of the blade portion 116 in the front-rear direction. The first contact portion 320 and the second contact portion 322 contact the first contact portion 320 and the second contact portion 322 when the blade portion 116 moves upward relative to the blade cover 300. This maintains the state in which the cover portion 302 covers the blade portion 116.

[0090] The guide portion 306 includes a first guide portion 326, a second guide portion 328, a first bent portion 330, and a second bent portion 332. The first guide portion 326 is disposed forward of the second guide portion 328. The first guide portion 326 is connected to the upper end of the first contact portion 320. The second guide portion 328 is connected to the upper end of the second contact portion 322. The first guide portion 326 is disposed away from the second guide portion 328 in the front-rear direction. The first guide portion 326 is disposed facing the second guide portion 328 in the front-rear direction. The first guide portion 326 extends from the lower end toward the front upper side. The second guide portion 328 extends from the lower end toward the rear upper side. Therefore, the distance between the first guide portion 326 and the second guide portion 328 in the front-rear direction gradually increases from the lower end toward the upper end.

[0091] The first bent portion 330 is connected to the upper end of the first guide portion 326. The second bent portion 332 is connected to the upper end of the second guide portion 328. The first bent portion 330 extends from the upper end of the first guide portion 326 toward the lower front side, then bends and extends toward the lower rear side. The second bent portion 332 extends from the upper end of the second guide portion 328 toward the lower rear side, then bends and extends toward the lower front side. This can prevent the user from touching the end of the guide portion 306.

[0092] The release section 308 is elastically deformable. The release section 308 includes a first operating section 336, a second operating section 338, a first placing section 340, a second placing section 342, a third guide section 344, a fourth guide section 346, and an attachment section 348. The first operating section 336 is disposed forward of the second operating section 338. The first operating section 336 is connected to the lower end of the first cover section 314. The second operating section 338 is connected to the lower end of the second cover section 316. The first operating section 336 is disposed away from the second operating section 338 in the front-rear direction. The first operating section 336 extends from the upper end toward the front lower side. The second operating section 338 extends from the upper end toward the rear lower side. Therefore, the distance between the first operating section 336 and the second operating section 338 in the front-rear direction increases from the upper end toward the lower end.

[0093] The first mounting portion 340 and the second mounting portion 342 have a flat plate shape. The first mounting portion 340 is disposed forward of the second mounting portion 342. The first mounting portion 340 is connected to the lower end of the first operating portion 336. The second mounting portion 342 is connected to the lower end of the second operating portion 338. The first mounting portion 340 is disposed away from the second mounting portion 342 in the front-rear direction. The first mounting portion 340 extends rearward from the lower end of the first operating portion 336. The second mounting portion 342 extends forward from the lower end of the second operating portion 338. The first mounting portion 340 and the second mounting portion 342 are disposed on the same plane. When the blade cover 300 is placed on the ground G, the first mounting portion 340 and the second mounting portion 342 come into contact with the ground G. The first mounting portion 340 and the second mounting portion 342 are substantially parallel to the ground G. The first mounting portion 340 and the second mounting portion 342 are in surface contact with the ground G. This makes it possible to prevent the blade cover 300 on the ground G from falling over.

[0094] The third guide portion 344 is disposed forward of the fourth guide portion 346. The third guide portion 344 is connected to the rear end of the first mounting portion 340. The fourth guide portion 346 is connected to the front end of the second mounting portion 342. The third guide portion 344 is disposed away from the fourth guide portion 346 in the front-rear direction. The third guide portion 344 is disposed facing the fourth guide portion 346 in the front-rear direction. The third guide portion 344 extends from the rear end of the first mounting portion 340 toward the rear upper side. The fourth guide portion 346 extends from the front end of the second mounting portion 342 toward the front upper side. The distance between the third guide portion 344 and the fourth guide portion 346 in the front-rear direction gradually decreases from the lower end to the upper end.

[0095] The mounting portion 348 is connected to the upper end of the third guide portion 344 and the upper end of the fourth guide portion 346. The mounting portion 348 includes a first mounting portion 350, a second mounting portion 352, and a third mounting portion 354. The first mounting portion 350 is disposed forward of the second mounting portion 352. The first mounting portion 350 is connected to the upper end of the third guide portion 344. The second mounting portion 352 is connected to the upper end of the fourth guide portion 346. The first mounting portion 350 is disposed away from the second mounting portion 352 in the front-rear direction. The first mounting portion 350 is disposed facing the second mounting portion 352 in the front-rear direction. The first mounting portion 350 extends from the lower end toward the front upper side, then bends and extends toward the rear upper side. The second mounting portion 352 extends from the lower end toward the rear upper side, then bends and extends toward the front upper side.

[0096] The third mounting portion 354 connects the upper end of the first mounting portion 350 and the upper end of the second mounting portion 352. The third mounting portion 354 extends in approximately the front-rear direction. The third mounting portion 354 is approximately parallel to both the ground G and the lower surface of the blade portion 116. The third mounting portion 354 has an insertion hole 356. The insertion hole 356 penetrates the third mounting portion 354 in the thickness direction (up-down direction). As shown in FIG. 25, the insertion hole 356 is disposed at the center of the third mounting portion 354 in the longitudinal direction.

[0097] The frictional force imparting part 310 is made of, for example, an elastic material. The frictional force imparting part 310 is, for example, friction rubber. The frictional force imparting part 310 is inserted into the insertion hole 356. The frictional force imparting part 310 is fixed to the third attachment part 354. The frictional force imparting part 310 protrudes upward from the insertion hole 356 and also protrudes downward from the insertion hole 356.

[0098] When the blade cover 300 is attached to the blade portion 116, the upper part of the frictional force imparting part 310 abuts against the lower surface of the blade portion 116. When a force causing the blade cover 300 to slide leftward relative to the blade portion 116 is applied to the blade portion 116 or the blade cover 300, the frictional force imparting part 310 applies a rightward frictional force (frictional force in the direction opposite to the leftward direction) to the blade portion 116. When a force causing the blade cover 300 to slide rightward relative to the blade portion 116 is applied to the blade portion 116 or the blade cover 300, the frictional force imparting part 310 applies a leftward frictional force (frictional force in the direction opposite to the rightward direction) to the blade portion 116. This prevents the blade cover 300 from sliding left and right relative to the blade portion 116. Therefore, for example, the blade cover 300 is prevented from sliding in the left-right direction relative to the blade portion 116 due to its own weight, and the blade cover 300 is prevented from coming off the blade portion 116. Also, rattling of the blade cover 300 relative to the blade portion 116 can be suppressed.

[0099] The blade cover 300 of this embodiment can be attached to the blade portion 116 by three different methods. As shown in FIG. 26, with the blade cover 300 placed on the ground G, the user grips the work machine 2 (see FIG. 24) and moves the blade portion 116 downward from above the first guide portion 326 and the second guide portion 328. This causes the blade cover 300 to elastically deform, and the first guide portion 326 and the second guide portion 328 move away from each other in the front-rear direction. That is, the first guide portion 326 moves from the initial position in a moving away direction D5, and the second guide portion 328 moves from the initial position in a moving away direction D6 opposite to the moving away direction D5. This causes the first contact portion 320 and the second contact portion 322 to move away from each other in the front-rear direction. When the user moves the blade portion 116 below the lower end of the first guide portion 326 and the lower end of the second guide portion 328, the first guide portion 326 and the second guide portion 328 approach each other in the front-rear direction due to the elastic restoring force of the blade cover 300. The first guide portion 326 moves in the direction opposite to the separation direction D5 to the initial position, and the second guide portion 328 moves in the direction opposite to the separation direction D6 to the initial position. As a result, the first abutment portion 320 and the second abutment portion 322 approach each other in the front-rear direction, and the first abutment portion 320 and the second abutment portion 322 are positioned above the cutting edge 116a of the blade portion 116. The user can easily attach the blade cover 300 to the blade portion 116 by a simple operation of pressing the blade portion 116 against the blade cover 300 from above.

[0100] Also, the user grips the blade cover 300 and applies a force to the release portion 308 against the elastic restoring force of the release portion 308. Specifically, the user operates the first operation portion 336 and the second operation portion 338 in a direction in which the first operation portion 336 and the second operation portion 338 approach each other. Due to the elastic deformation of the release portion 308, the first operation portion 336 moves from the initial position in an approaching direction D7, and the second operation portion 338 moves from the initial position in an approaching direction D8 opposite to the approaching direction D7. With the movement of the first operation portion 336 and the second operation portion 338, the first guide portion 326 moves from the initial position in a separating direction D5, and the second guide portion 328 moves from the initial position in a separating direction D6 opposite to the separating direction D5. As a result, the first contact portion 320 and the second contact portion 322 move away from each other in the front-rear direction. Next, the user moves the blade cover 300 upward relative to the blade portion 116. This allows the user to attach the blade cover 300 to the blade unit 116 by a simple operation of operating the first operating unit 336 and the second operating unit 338.

[0101] 27, when a user holds the blade cover 300 with his / her hand and moves the blade cover 300 leftward (or rightward) relative to the blade portion 116 so as to approach the blade portion 116, the blade portion 116 moves leftward (or rightward) between the cover portion 302 and the abutment portion 304. This allows the user to easily attach the blade cover 300 to the blade portion 116 by a simple operation of sliding the blade cover 300 leftward (or rightward) relative to the blade portion 116.

[0102] In addition, the blade cover 300 of this embodiment can be removed from the blade portion 116 by two kinds of methods. As shown in FIG. 24, the user grips the blade cover 300 and applies a force to the release portion 308 that resists the elastic restoring force of the release portion 308. Specifically, the user operates the first operation portion 336 and the second operation portion 338 in a direction in which the first operation portion 336 and the second operation portion 338 approach each other. Due to the elastic deformation of the release portion 308, the first operation portion 336 moves from the initial position in an approaching direction D7, and the second operation portion 338 moves from the initial position in an approaching direction D8 opposite to the approaching direction D7. With the movement of the first operation portion 336 and the second operation portion 338, the first guide portion 326 moves from the initial position in a separating direction D5, and the second guide portion 328 moves from the initial position in a separating direction D6 opposite to the separating direction D5. As a result, the first contact portion 320 and the second contact portion 322 move away from each other in the front-rear direction. Next, when the user moves the blade portion 116 upward relative to the blade cover 300, the blade cover 300 is removed from the blade portion 116. As a result, the user can remove the blade cover 300 from the blade portion 116 by a simple operation of operating the first operating portion 336 and the second operating portion 338.

[0103] 27, the user grasps the blade cover 300 with the hand while the blade cover 300 is attached to the blade portion 116, and moves the blade cover 300 to the left (or right) relative to the blade portion 116. The user can easily remove the blade cover 300 from the blade portion 116 by the simple operation of sliding the blade cover 300 left or right relative to the blade portion 116.

[0104] In addition, the blade cover 300 of this embodiment can be attached to the pole 4 of the work machine 2. As shown in FIG. 28, the shortest distance between the third guide portion 344 and the fourth guide portion 346 in the front-rear direction is shorter than the diameter of the pole 4. When a user grips the blade cover 300 and moves the third guide portion 344 and the fourth guide portion 346 downward from the upper side of the pole 4, the release portion 308 is elastically deformed, and the third guide portion 344 and the fourth guide portion 346 move away from each other in the front-rear direction. That is, the third guide portion 344 moves from the initial position in a moving away direction D9, and the fourth guide portion 346 moves from the initial position in a moving away direction D10 opposite to the moving away direction D9. When the pole 4 moves into the attachment portion 348, the third guide portion 344 and the fourth guide portion 346 approach each other in the front-rear direction due to the elastic restoring force of the release portion 308. The third guide portion 344 moves in the direction opposite to the separating direction D9 toward the initial position, and the fourth guide portion 346 moves in the direction opposite to the separating direction D10 toward the initial position. The user can easily attach the blade cover 300 to the pole 4 with a simple operation.

[0105] 29 , when the blade cover 300 is attached to the pole 4, the attachment portion 348 surrounds the pole 4. The attachment portion 348 is pressed against the pole 4 by the elastic restoring force of the release portion 308. This makes it possible to prevent the blade cover 300 from coming off the pole 4.

[0106] (effect) The working machine 2 of this embodiment includes a front end housing 40 (an example of a housing), a blade 86 (an example of a working member) that is swingably supported by the front end housing 40 and is at least partially disposed outside the front end housing 40, and a counterweight 88 that is disposed inside the front end housing 40 and swings when the blade 86 swings. The blade 86 and the counterweight 88 swing toward each other and swing away from each other.

[0107] According to the above configuration, the vibration of the front end housing 40 caused by the swing of the blade 86 can be offset by the vibration of the front end housing 40 caused by the swing of the counterweight 88. As a result, the vibration of the front end housing 40 can be reduced.

[0108] The work machine 2 further includes a motor 20 (an example of a prime mover) and a transmission mechanism 90 disposed inside the front end housing 40. The transmission mechanism 90 includes a rotating member 91 that rotates about a rotation axis AX1 by operation of the motor 20, a first transmission unit 78 that is attached to the rotating member 91 and transmits the rotation of the rotating member 91 to the blade 86, and a second transmission unit 80 that is attached to the rotating member 91 and transmits the rotation of the rotating member 91 to the counterweight 88.

[0109] According to the above configuration, both the first transmission unit 78 and the second transmission unit 80 can be operated by the operation of one rotating member 91. This makes it possible to reduce the number of parts.

[0110] Furthermore, the first transmission unit 78 includes a first rod 100 attached to the rotating member 91. The second transmission unit 80 includes a third rod 136 (an example of a second rod) attached to the rotating member 91. When the work machine 2 is viewed along the rotation axis AX1, the first rod 100 at least partially overlaps with the third rod 136.

[0111] In a configuration in which the first rod 100 does not at least partially overlap with the third rod 136 when the working machine 2 is viewed along the rotation axis AX1, the working machine 2 becomes larger in size in a direction perpendicular to the rotation axis AX1. According to the above configuration, the first rod 100 at least partially overlaps with the third rod 136 when the working machine 2 is viewed along the rotation axis AX1, so that it is possible to prevent the working machine 2 from becoming larger in size in a direction perpendicular to the rotation axis AX1.

[0112] The first transmission unit 78 further includes a first connecting spindle 102 (an example of a first spindle) and a second rod 104 (an example of a third rod) that is movably attached to the first rod 100 via the first connecting spindle 102 and transmits the movement of the first rod 100 to the blade 86. The second transmission unit 80 further includes a second connecting spindle 138 (an example of a second spindle) and a fourth rod 140 that is movably attached to the third rod 136 via the second connecting spindle 138 and transmits the movement of the third rod 136 to the counterweight 88.

[0113] According to the above configuration, since the first transmission unit 78 includes the second rod 104, it is possible to easily adjust the position of the central axis AX2 of the blade 86. Furthermore, since the second transmission unit 80 includes the fourth rod 140, it is possible to easily adjust the position of the central axis AX3 of the counterweight 88.

[0114] The work machine 2 also includes a first output shaft 82 that connects the first transmission unit 78 and the blade 86 and extends along a central axis AX2 (an example of an oscillating axis) of the blade 86, and a second output shaft 84 that connects the second transmission unit 80 and the counterweight 88 and extends along a central axis AX3 (an example of an oscillating axis) of the counterweight 88.

[0115] According to the above configuration, the first output shaft 82 makes it possible to easily adjust the position of the blade 86 relative to the first transmission unit 78 in the direction in which the central axis AX2 of the blade 86 extends. Moreover, the second output shaft 84 makes it possible to easily adjust the position of the counterweight 88 relative to the second transmission unit 80 in the direction in which the central axis AX3 of the counterweight 88 extends.

[0116] Further, the distance between the rotation axis AX1 of the rotating member 91 and the central axis AX2 of the blade 86 is substantially the same as the distance between the rotation axis AX1 of the rotating member 91 and the central axis AX3 of the counterweight 88.

[0117] According to the above configuration, the vibration of the front end housing 40 caused by the swing of the blade 86 can be offset by the vibration of the front end housing 40 caused by the swing of the counterweight 88. As a result, the vibration of the front end housing 40 can be further reduced.

[0118] The blade 86 also has a first location 128 and a second location 132 supported by the front end housing 40. The first location 128 and the second location 132 are disposed on a central axis AX2 of the blade 86. The counterweight 88 is disposed between the first location 128 and the second location 132 in the direction along the central axis AX2 of the blade 86.

[0119] In a configuration in which the counterweight 88 is not disposed between the first location 128 and the second location 132 in the direction along the central axis AX2 of the blade 86, the blade 86 may tilt due to the weight of the counterweight 88. According to the above configuration, the counterweight 88 is disposed between the first location 128 and the second location 132 in the direction along the central axis AX2 of the blade 86, so that the blade 86 can be prevented from tilting due to the weight of the counterweight 88.

[0120] The work machine 2 further includes a pole 4 that is fixed to the front end housing 40 and extends in the longitudinal direction, and a loop handle 6 (an example of a handle) that is fixed to the pole 4 and is held by a user.

[0121] According to the above configuration, a user grips the loop handle 6 to handle the pole-type working machine 2. If the front end housing 40 vibrates due to the swinging of the blade 86, the vibration of the front end housing 40 will cause the handling of the pole-type working machine 2 to become difficult. According to the above configuration, the vibration of the front end housing 40 caused by the swinging of the blade 86 is offset by the vibration of the front end housing 40 caused by the swinging of the counterweight 88, so that the handling of the pole-type working machine 2 can be prevented from becoming difficult.

[0122] The blade 86 also digs into the ground.

[0123] According to the above configuration, the blade 86 digs up the ground, causing the front end housing 40 to vibrate. Therefore, vibrations caused by the swinging of the blade 86 and vibrations caused by the blade 86 digging up the ground are generated in the front end housing 40. This causes the front end housing 40 to vibrate significantly. According to the above configuration, the vibrations of the front end housing 40 caused by the swinging of the blade 86 can be offset by the vibrations of the front end housing 40 caused by the swinging of the counterweight 88. This makes it possible to reduce the vibrations of the front end housing 40.

[0124] (Modification) The work machine 2 according to one embodiment may be a work machine other than a grass digger, for example, a lawn mower, a reciprocating saw, a hedge trimmer, a ground trimmer, or a broom.

[0125] The work machine 2 according to one embodiment may be provided with a prime mover other than the motor 20, for example, an engine.

[0126] In one embodiment, a blade cover 300 may be attached to the front end housing 40 to cover the blade portion 116 .

[0127] The cross-sectional shape of the blade cover 300 according to an embodiment does not have to be substantially uniform in the left-right direction.

[0128] In the work machine 2 according to the embodiment, the positioning portion 180 of the adjustment member 160 has three flat surfaces 190, 192, and 194. In a modified example, the number of flat surfaces is not limited to three, and may be, for example, two, or may be four or more and twelve or less.

[0129] In the work machine 2 according to one embodiment, the adjust member 160 may have a protrusion instead of the receiving groove 198. In this case, the right mounting portion 120 and the left mounting portion 124 of the blade 86 may have a receiving groove instead of the protrusions 254, 274. [Explanation of symbols]

[0130] 2: Work equipment 4: Paul 6: Loop handle 8: Rear end unit 10: Front end unit 20: Motor 40: Front end housing 68: Rotating shaft 76: Disk 78: First transmission unit 80: Second transmission unit 82: First output shaft 84: 2nd output shaft 86: Blade 88: Counterweight 90: Transmission mechanism 91: Rotating parts 100: 1st rod 102: 1st connecting spindle 104: 2nd Rod 116: Blade section 120: Right mounting part 124: Left mounting part 128: First Place 132: Second Place 136: 3rd Rod 138: Second connecting spindle 140: 4th Rod 160: Adjustment member 170: First adjustment member 172: Second adjustment member 174a: Outer surface 176: Mounting part 178: Adjustment section 180: Positioning section 190: 1st plane part 192: 2nd plane part 194:Third plane part 198: Receiving groove 204: Right plate mounting part 206: Left plate mounting part 214: Right shaft positioning part 222: First right shaft flat section 224: Second right shaft flat section 226: Third right shaft flat section 234: Left shaft positioning part 242: First left shaft flat section 244: Second left shaft flat section 246: Third left shaft flat section 254: Right protrusion 274 :Left protrusion 300: Blade cover 302: Cover part 304: Contact part 306: Information Department 308: Release section 310: Friction force applying section 314: First cover part 316: Second cover part 320: 1st contact part 322:Second contact part 336: 1st operation section 338:Second operation section 340: First placement section 342: Second placement section 348: Mounting part AX1: Rotation axis AX2, AX3: Center axis AX3: Central axis BP: Battery pack D1: 1st direction D2 :Second direction D3: Third direction D4: 4th direction D5, D6, D9, D10: Leaving direction D7, D8: Approach direction G: Ground W1, W2: Width

Claims

1. Housing and A working member is pivotably supported in the housing and at least partially located outside the housing, The housing is provided with a counterweight that is located inside the housing and swings when the working member swings, A work machine in which the work member and the counterweight swing toward each other and toward each other.

2. The prime mover and The housing further comprises a transmission mechanism located inside the housing, The aforementioned transmission mechanism is A rotating member that rotates around a rotation axis due to the operation of the prime mover, A first transmission unit is attached to the rotating member and transmits the rotation of the rotating member to the working member, The work machine according to claim 1, further comprising a second transmission unit attached to the rotating member, which transmits the rotation of the rotating member to the counterweight.

3. The first transmission unit includes a first rod attached to the rotating member, The second transmission unit includes a second rod attached to the rotating member, The work implement according to claim 2, wherein, when the work implement is viewed along the rotation axis, the first rod overlaps with the second rod at least partially.

4. The first transmission unit is, First spindle and The system further comprises a third rod which is movably mounted to the first rod via the first spindle and transmits the movement of the first rod to the working member, The second transmission unit is The second spindle and The work machine according to claim 3, further comprising a fourth rod which is movably mounted to the second rod via the second spindle and transmits the movement of the second rod to the counterweight.

5. The first transmission unit and the working member are connected, and the first output shaft extends along the pivot axis of the working member, The work machine according to claim 2, further comprising: a second output shaft connecting the second transmission unit and the counterweight, and extending along the pivot axis of the counterweight.

6. The work machine according to claim 2, wherein the distance between the rotation axis of the rotating member and the pivot axis of the work member is substantially the same as the distance between the rotation axis of the rotating member and the pivot axis of the counterweight.

7. The working member has a first and a second location that is supported by the housing, The first and second locations are positioned on the pivot axis of the working member, The work machine according to claim 1, wherein the counterweight is positioned between the first location and the second location with respect to the direction of the pivot axis of the work member.

8. A pole fixed to the housing and extending in the longitudinal direction, The work machine according to claim 1, further comprising a handle fixed to the pole and grasped by a user.

9. The work machine according to any one of claims 1 to 8, wherein the work member is equipped with a blade for digging up the ground.

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