Grounding body and grass mower with grounding body

Abstract

To provide a technique capable of reducing a possibility of damaging a grounding body and notifying a user of timing to replace the grounding body.SOLUTION: A grounding body comprises a grounding part coming into contact with the ground, a curved surface part having a curved shape extending radially outward and upward from the grounding part, and a groove part at least a portion of which is provided in the curved surface part. The groove part includes a first groove portion having a first shape, and a second groove portion communicating with the first groove portion and having a second shape different from the first shape. An upper end of the second groove portion is positioned above an upper end of the first groove portion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a ground contact body and a brush cutter equipped with the ground contact body. [Background technology]

[0002] Patent Document 1 discloses a grounding body that is attached to the cutting blade shaft of a brush cutter. This grounding body has a main body that comes into contact with the ground. The main body has a recess with a bottom that is recessed from the inner circumferential surface of the main body toward the outer circumferential surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-35731 Summary of the Invention [Problem to be solved by the invention]

[0004] When a brush cutter is used, the main body that comes into contact with the ground wears. When the wear of the main body reaches a certain point, the ground contact body needs to be replaced. Patent Document 1 uses a recess in the main body to notify the user when it is time to replace the ground contact body. Specifically, before the main body is worn, the recess in the main body is not visible from the outside. When the main body is worn and the recess in the main body changes into a through-hole, the part of the main body that corresponds to the recess in the main body can be seen from the outside. Patent Document 1 notifies the user of this timing as the time to replace the ground contact body. However, with this configuration, when the main body wears and the recess changes into a through-hole, the strength of the main body decreases. Therefore, if the user continues to use the ground contact body without realizing that it is time to replace it, the main body of the ground contact body may be damaged.

[0005] This specification provides a technology that reduces the possibility of damage to the grounding body and can notify the user when it is time to replace the grounding body. [Means for solving the problem]

[0006] This specification discloses a grounding body attached to a cutting blade shaft of a brush cutter. The grounding body may include a grounding portion that contacts the ground, a curved surface portion that extends radially outward and upward from the grounding portion, and a groove portion, at least a portion of which is provided in the curved surface portion. The groove portion may include a first groove portion having a first shape and a second groove portion that is connected to the first groove portion and has a second shape different from the first shape. The upper end of the second groove portion may be located above the upper end of the first groove portion.

[0007] This specification also discloses a brush cutter. The brush cutter may include an operating rod, a blade shaft provided at the front of the operating rod, a blade attached to the blade shaft, and a grounding body attached to the blade shaft below the blade and in contact with the ground. The grounding body may include a grounding portion that contacts the ground, a curved surface portion having a curved shape extending radially outward and upward from the grounding portion, and a groove portion, at least a portion of which is provided in the curved surface portion. The groove portion may include a first groove portion having a first shape and a second groove portion that is connected to the first groove portion and has a second shape different from the first shape. An upper end of the second groove portion may be located above an upper end of the first groove portion.

[0008] According to the above configuration, as the main body wears, the shape of the groove along the outer circumferential surface of the main body changes from a first shape to a second shape. Because the shape of the groove is reflected in the curved surface, the user can know that it is time to replace the grounding body when the shape of the groove changes from the first shape to the second shape. Therefore, the grounding body is replaced before a through hole is formed in the main body. This reduces the possibility of damage to the grounding body and notifies the user when it is time to replace the grounding body. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 2 is a right side view of the mower 2 of the embodiment as seen from the right. [Figure 2] FIG. 2 is a right cross-sectional view of the grass cutter 2 of the embodiment. [Figure 3] FIG. 3 is an enlarged view of a part of the right cross-sectional view of FIG. 2. [Figure 4] FIG. 2 is a perspective view of the mounting portion 70 of the embodiment as viewed from the upper right front. [Figure 5] FIG. 2 is a perspective view of the mounting portion 70 of the embodiment as viewed from the upper right front. [Figure 6] FIG. 10 is a bottom view of the main body 72 of the embodiment. [Figure 7] FIG. 10 is a rear cross-sectional view of the main body 72 of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Representative, non-limiting embodiments 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 preferred embodiments 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 in conjunction with other features and inventions to provide further improved ground-contacting bodies and mowers.

[0011] Furthermore, the combinations of features and steps disclosed in the following detailed description are not essential to practicing the invention in its broadest sense, but are described solely to specifically illustrate exemplary embodiments of the invention. Furthermore, the various features of the following exemplary embodiments and those described in the claims do not necessarily have to be combined in the exact embodiments described herein or in the exact order listed to provide additional and useful embodiments of the invention.

[0012] All features described in this 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.

[0013] In one or more embodiments, the grounding body may include a grounding portion that contacts the ground, a curved surface portion that has a curved shape extending radially outward and upward from the grounding portion, and a groove portion, at least a portion of which is provided in the curved surface portion. The groove portion may include a first groove portion having a first shape and a second groove portion that is connected to the first groove portion and has a second shape different from the first shape. An upper end of the second groove portion may be located higher than an upper end of the first groove portion.

[0014] In one or more embodiments, when the grounding body is viewed from below, the second groove portion may be disposed inside the first groove portion.

[0015] With this configuration, the area of the second grooves when viewed from below the ground contacting member is smaller than the area of the first grooves. Therefore, compared to a configuration in which the area of the second grooves is larger than the area of the first grooves, it is possible to prevent a decrease in the strength of the ground contacting member when the main body wears and the shape of the grooves along the outer circumferential surface of the main body changes to a shape corresponding to the second grooves.

[0016] In one or more embodiments, when the grounding body is viewed from below, the first groove portion may have a shape with a longitudinal direction along the circumferential direction, and the second groove portion may have a circular shape.

[0017] When a user presses the grounding body against the ground, the periphery of the first groove portion may come into contact with the ground. If the first groove portion has a shape with a longitudinal direction along the left-right direction, a larger portion of the periphery of the first groove portion comes into contact with the ground compared to a configuration in which the first groove portion has a shape with a longitudinal direction in the circumferential direction. If the portion that comes into contact with the ground is larger, the resistance when the user moves the brush cutter increases. With the above configuration, the portion of the periphery of the first groove portion that comes into contact with the ground can be made smaller. Therefore, the resistance when the user moves the brush cutter can be reduced, improving operability.

[0018] In one or more embodiments, the grounding body may further include a plurality of the grooves, and the plurality of grooves may be arranged at equal intervals in the circumferential direction.

[0019] If the grounding body is attached to the blade shaft of a brush cutter and the grounding body is inclined relative to the blade of the brush cutter, only a portion of the curved surface may come into contact with the ground, and the portion of the curved surface where the grooves are provided may not wear. With the above configuration, even if the grounding body is inclined relative to the blade, the portion of the curved surface where the grooves are provided can be more likely to wear. This increases the likelihood that the user will know when to replace the grounding body. Furthermore, the strength of the grounding body can be increased compared to a configuration in which the grooves are provided continuously in the circumferential direction.

[0020] In one or more embodiments, the grounding body may further include an attachment portion for attaching the grounding body to the blade shaft, and a main body portion having the grounding portion, the curved surface portion, and the groove portion. The grounding body may be attached to the blade shaft by a nut member. The attachment portion may have a through hole through which the blade shaft passes. An upper end of the second groove portion may be located below a lower end of the blade shaft and a lower end of the nut member.

[0021] As the main body part wears, there is a risk that the blade shaft or the nut member will come into contact with the ground. In particular, if the outer peripheral surface of the nut member wears, it becomes difficult to remove the nut member using tools. This means that the grounding body and the cutting blade cannot be easily replaced. Therefore, it is desirable to replace the grounding body before the blade shaft or the nut member comes into contact with the ground. According to the above configuration, the upper end of the second groove portion is located lower than the lower end of the blade shaft and the lower end of the nut member. Therefore, the user can know that it is time to replace the grounding body when the shape of the groove portion along the outer peripheral surface of the main body part changes from the first shape to the second shape. Therefore, the user can replace the grounding body before the blade shaft or the nut member comes into contact with the ground. As a result, wear of the blade shaft and the nut member can be suppressed.

[0022] (Example) The grass cutter 2 will be described with reference to Figures 1 to 6. As shown in Figure 1, the grass cutter 2 includes a cutting blade unit 10, an operating rod 12, and a rear housing 14. Hereinafter, the direction perpendicular to the ground P1 in Figure 1 will be referred to as the up-down direction, the direction perpendicular to the up-down direction in Figure 1 will be referred to as the front-rear direction, and the direction perpendicular to the up-down direction and the front-rear direction will be referred to as the left-right direction.

[0023] The cutting blade unit 10 is provided on the front part 12a of the operating rod 12, and a rear housing 14 is provided on the rear part 12b of the operating rod 12. The operating rod 12 extends rearward and upward from the cutting blade unit 10. The operating rod 12 connects the cutting blade unit 10 and the rear housing 14.

[0024] The control rod 12 has a hollow pipe shape and extends linearly. The control rod 12 is provided with a loop handle 20 for a user to grip. A grip 22 is provided between the loop handle 20 of the control rod 12 and the rear housing 14. The grip 22 is formed to cover the outer periphery of the control rod 12. The grip 22 has a lock-off lever 24 provided on the upper surface and a start switch 26 provided on the lower surface. The lock-off lever 24 is a lever for restricting and releasing the depression of the start switch 26. The start switch 26 is a switch for driving a motor (not shown), which will be described later. When the start switch 26 is not pressed, the supply of power to the motor is cut off. When the start switch 26 is pressed, power is supplied to the motor. When the lock-off lever 24 is not pressed, the depression of the start switch 26 is restricted. When the lock-off lever 24 is pressed in, the restriction on the pressing operation of the start switch 26 is released. A transmission shaft 28 (see Figure 2) that is rotated by the drive of the motor is rotatably housed inside the operating rod 12.

[0025] The rear housing 14 accommodates a motor (not shown) and a control board (not shown). The motor may be a brushless DC motor, a brushed DC motor, or another type of motor such as an AC motor. In a modified example, the rear housing 14 may accommodate an engine (not shown). The control board controls the operation of the motor. One end of a power cable 30 is connected to the rear of the rear housing 14. A connector 32 is provided at the other end of the power cable 30. A power cable extending from an external power source such as a battery unit (not shown) is connected to the connector 32. The motor operates using power supplied via the power cable 30. The motor may also operate using power supplied from a battery pack.

[0026] As shown in FIG. 1, the blade unit 10 includes a gear housing 40, a safety cover 42, a cutting blade 44, a grounding member 46, and a nut member 48 (see FIG. 2). The cutting blade 44 has two blades, one extending forward and the other extending rearward. The cutting blade 44 is made of metal. In a modified example, the cutting blade 44 may have four blades, eight blades, or a disc-shaped chip saw. In another modified example, the cutting blade 44 may be made of nylon cord. As shown in FIG. 2, an insertion hole 40a is provided at the upper rear of the gear housing 40 for inserting the front portion 12a of the operating rod 12. The gear housing 40 accommodates a first gear 50, a second gear 52, and a cutting blade shaft 54. The transmission shaft 28 is attached to the first gear 50. The cutting blade shaft 54 is attached to the second gear 52. The first gear 50 meshes with the second gear 52. The first gear 50 and the second gear 52 are bevel gears.

[0027] An opening 40b is provided at the bottom of the gear housing 40. The cutting blade unit 10 further includes a transmission part 60 and a metal fitting 62. The transmission part 60 is disposed inside the opening 40b. The transmission part 60 includes a first cylindrical part 60a and a first circular plate part 60b extending radially outward from the first cylindrical part 60a. The metal fitting 62 is provided on the underside of the first circular plate part 60b of the transmission part 60. The cutting blade 44 is provided on the underside of the metal fitting 62.

[0028] The grounding body 46 includes an attachment portion 70 and a main body portion 72. The attachment portion 70 includes an inner attachment portion 80 and a plurality of outer attachment portions 82. As shown in FIG. 4, the inner attachment portion 80 includes a second circular plate portion 84, a tubular portion 86, and a connecting portion 88. The outer shape of the tubular portion 86 is composed of arc portions 86a curved in an arc shape and flat portions 86b. The arc portions 86a are arranged at equal intervals in the circumferential direction. The flat portions 86b linearly connect the ends of two adjacent arc portions 86a in the circumferential direction. The inner shape of the tubular portion 86 is circular. The outer attachment portion 82 includes a radially extending portion 90 extending radially outward from the lower end of the arc portion 86a of the tubular portion 86, and an axially extending portion 92 extending upward from the radially outer end of the radially extending portion 90. The upper end of the axially extending portion 92 is located lower than the upper end of the tubular portion 86. A first groove 94 extending in the circumferential direction is defined by the outer mounting portion 82 and the tubular portion 86. The first groove 94 is recessed downward. As shown in FIG. 3 , the diameter of the first through hole 84a of the second circular plate portion 84 is slightly larger than the outer diameter of the cutting blade shaft 54 and smaller than the outer shape of the nut member 48. The first through hole 84a, through which the cutting blade shaft 54 passes in the axial A direction, is provided in the center of the second circular plate portion 84. The inner diameter of the tubular portion 86 is larger than the outer shape of the second circular plate portion 84. The lower and upper ends of the tubular portion 86 are located higher than the lower and upper ends of the second circular plate portion 84, respectively. The connecting portion 88 connects the second circular plate portion 84 and the tubular portion 86.

[0029] As shown in FIG. 5 , the main body 72 includes a second cylindrical portion 100, a fixing portion 102, a flange portion 104, a third cylindrical portion 106, and a fourth cylindrical portion 108. For example, the main body 72 is formed by injection molding. The fixing portion 102 includes a third circular plate 110 having a second through-hole 110a at its center, a fourth circular plate 112 having an opening 112a, and a plurality of fixing grooves 114. The third circular plate 110 and the fourth circular plate 112 extend radially inward from the inner circumferential surface of the second cylindrical portion 100. The fourth circular plate 112 is connected to the upper end of the second cylindrical portion 100. The third circular plate 110 is disposed below the fourth circular plate 112. As shown in Fig. 3, the diameter of the second through hole 110a of the third circular plate portion 110 is larger than the outer diameter of the cutting blade shaft 54 and the nut member 48. The diameter of the second through hole 110a is also larger than the first through hole 84a of the second circular plate portion 84. As shown in Fig. 5, the opening 112a of the fourth circular plate portion 112 has a shape corresponding to the outer shapes of the arc portion 86a and the flat portion 86b (see Fig. 4) of the tubular portion 86 of the mounting portion 70. The fixing groove portion 114 has a shape corresponding to the outer mounting portion 82 (see Fig. 4) of the mounting portion 70.

[0030] As shown in FIG. 3 , the flange portion 104 extends radially outward from the lower end of the second cylindrical portion 100 while curving. The fourth cylindrical portion 108 extends upward from the outer circumferential end and upper end of the flange portion 104. The third cylindrical portion 106 extends upward from the inner circumferential surface of the flange portion 104 between the second cylindrical portion 100 and the fourth cylindrical portion 108. A second groove 109 extending in the circumferential direction is defined by the second cylindrical portion 100, the flange portion 104, and the third cylindrical portion 106. The upper end of the second cylindrical portion 100 is located slightly below the upper end of the tubular portion 86 of the mounting portion 70. The upper ends of the third cylindrical portion 106 and the fourth cylindrical portion 108 are also located slightly below the upper end of the second cylindrical portion 100. Therefore, when the grounding member 46 is attached to the blade shaft 54 by the nut member 48, the main body portion 72 does not contact the blade 44.

[0031] The main body outer peripheral surface 72a of the main body 72 is formed by the lower surface 100a of the second cylindrical portion 100, the flange outer peripheral surface 104a of the flange portion 104, and the cylindrical outer peripheral surface 108a of the fourth cylindrical portion 108. The lower end of the second cylindrical portion 100 is in contact with the ground P1. The lower surface 100a of the second cylindrical portion 100 is flat. The main body outer peripheral surface 72a of the main body 72 is provided with a plurality of replacement indicator grooves 120. As shown in FIG. 6, the plurality of replacement indicator grooves 120 are arranged at equal intervals along the circumferential direction. In this embodiment, three replacement indicator grooves 120 are provided on the main body outer peripheral surface 72a at 120° intervals. The plurality of replacement indicator grooves 120 are provided on the main body outer peripheral surface 72a of the main body 72, spanning the lower surface 100a of the second cylindrical portion 100 and the flange outer peripheral surface 104a of the flange portion 104. The exchange indicator groove 120 includes a first exchange indicator groove 122 and a second exchange indicator groove 124. When viewed along the axial A direction, the first exchange indicator groove 122 has a shape with a longitudinal direction in the circumferential direction. The radial center of the first exchange indicator groove 122 coincides with the boundary between the lower surface 100a of the second cylindrical portion 100 and the flange outer peripheral surface 104a of the flange portion 104. When viewed along the axial A direction, the second exchange indicator groove 124 has a circular shape. The radial width of the second exchange indicator groove 124 (i.e., the diameter of the circular shape of the second exchange indicator groove 124) when centered on the axial A is slightly smaller than the radial width of the first exchange indicator groove 122. That is, when viewed along the axial A direction, the second exchange indicator groove 124 is located inside the first exchange indicator groove 122. As shown in Fig. 7, the second change indicator groove 124 extends upward from the upper end of the first change indicator groove 122. That is, the first change indicator groove 122 and the second change indicator groove 124 are connected to each other. As shown in Fig. 3, the upper end of the second change indicator groove 124 is located lower than the lower end 54a of the cutting blade shaft 54, the lower end 48a of the nut member 48, and the bottom surface of the second recessed groove 109. For example, the height H1 of the upper end of the first change indicator groove 122 is 1.5 mm to 2.5 mm, and the height H2 of the upper end of the second change indicator groove 124 is 3.0 mm to 5.0 mm.Also, as an example, the inner diameter of the first exchange indication groove portion 122 is 50 mm to 52 mm, and the outer diameter of the first exchange indication groove portion 122 is 58 mm to 60 mm.

[0032] The nut member 48 engages with the lower part of the blade shaft 54. The lower end 54a of the blade shaft 54 is located lower than the lower end 48a of the nut member 48. By tightening the nut member 48, the blade 44 is clamped between the metal fitting 62 and the ground contact body 46 (more specifically, the mounting portion 70). In this state, when the blade shaft 54 rotates, the transmission unit 60, metal fitting 62, ground contact body 46, and blade 44 rotate integrally.

[0033] In one or more embodiments, as shown in FIG. 3 , the grounding member 46 includes a lower end portion of the second cylindrical portion 100 (an example of a "grounding portion") that contacts the ground P1, a flange outer peripheral surface 104a (an example of a "curved portion") of the flange portion 104 that has a curved shape extending radially outward and upward from the lower end portion of the second cylindrical portion 100, and an exchange indicator groove 120 (an example of a "groove"), at least a portion of which is provided in the flange outer peripheral surface 104a. The exchange indicator groove 120 includes a first exchange indicator groove 122 (an example of a "first groove") that has a shape that extends longitudinally in the circumferential direction (an example of a "first shape"), and a second exchange indicator groove 124 (an example of a "second groove") that is connected to the first exchange indicator groove 122 and has a circular shape. The upper end of the second exchange indicator groove 124 is located higher than the upper end of the first exchange indicator groove 122.

[0034] As the main body 72 of the grounding bar 46 wears, the shape of the replacement indicator groove 120 along the outer circumferential surface 72a of the main body 72 changes from an elongated hole shape to a circular shape. When the shape of the replacement indicator groove 120 changes from an elongated hole shape to a circular shape, the user knows that it is time to replace the grounding bar 46. Therefore, the grounding bar 46 is replaced before a through hole is formed in the main body 72. This reduces the possibility of damage to the grounding bar 46 and notifies the user when it is time to replace the grounding bar 46.

[0035] In one or more embodiments, as shown in FIG. 6, when the grounding body 46 is viewed from below, the second change indicator groove 124 is located inside the first change indicator groove 122.

[0036] With the above configuration, the area of the second change indicator groove 124 when the grounding body 46 is viewed from below is smaller than the area of the first change indicator groove 122. Therefore, compared to a configuration in which the area of the second change indicator groove is larger than the area of the first change indicator groove, the strength of the grounding body 46 can be improved when the main body 72 wears and the shape of the change indicator groove 120 along the main body outer surface 72a of the main body 72 changes to a circular shape corresponding to the second change indicator groove 124.

[0037] In one or more embodiments, as shown in FIG. 6, when the grounding body 46 is viewed from below, the first exchange indicator groove 122 has a shape with a longitudinal direction along the circumferential direction, and the second exchange indicator groove 124 has a circular shape.

[0038] When the user presses the grounding member 46 against the ground P1, the periphery of the first replacement indicator groove 122 may come into contact with the ground P1. If the first replacement indicator groove has a shape with a longitudinal direction along the left-right direction, a larger portion of the periphery of the first replacement indicator groove comes into contact with the ground P1 compared to a configuration in which the first replacement indicator groove 122 has a shape with a longitudinal direction along the circumferential direction. If the portion that comes into contact with the ground P1 is larger, the resistance when the user moves the brush cutter 2 increases. With the above configuration, the portion of the periphery of the first replacement indicator groove 122 that comes into contact with the ground P1 can be made smaller. Therefore, the resistance when the user moves the brush cutter 2 can be reduced, improving operability.

[0039] In one or more embodiments, as shown in Figure 6, the grounding body 46 further includes a plurality of replacement indicator grooves 120. The plurality of replacement indicator grooves 120 are equally spaced apart in the circumferential direction.

[0040] If the ground contact body 46 is attached to the blade shaft 54 of the brush cutter 2 and the ground contact body 46 is inclined relative to the cutting blade 44 of the brush cutter 2, only a portion of the flange portion 104 may come into contact with the ground surface P1, and the portion of the flange portion 104 where the replacement indicator groove 120 is provided may not wear. With the above-described configuration, even when the ground contact body 46 is inclined relative to the cutting blade 44, the portion of the flange portion 104 where the replacement indicator groove 120 is provided is more likely to wear. This increases the likelihood that the user will know when to replace the ground contact body 46. Furthermore, the strength of the ground contact body 46 can be increased compared to a configuration in which the replacement indicator groove 120 is provided continuously in the circumferential direction.

[0041] In one or more embodiments, the grounding body 46 includes an attachment portion 70 for attaching the grounding body 46 to the blade shaft 54, and a main body portion 72 having a grounding portion, a flange portion 104, and a replacement indicator groove 120. The grounding body 46 is attached to the blade shaft 54 by a nut member 48. The attachment portion 70 has a first through hole 84a (an example of a "through hole") through which the blade shaft 54 passes. The upper end of the second replacement indicator groove 124 is located below the lower end 54a of the blade shaft 54 and the lower end 48a of the nut member 48.

[0042] As the main body 72 wears, there is a risk that the blade shaft 54 or the nut member 48 will come into contact with the ground P1. In particular, if the outer peripheral surface of the nut member 48 wears down, it becomes difficult to remove the nut member 48 using tools. This means that the grounding member 46 and the cutting blade 44 cannot be easily replaced. Therefore, it is desirable to replace the grounding member 46 before the cutting blade shaft 54 or the nut member 48 comes into contact with the ground P1. According to the above configuration, the upper end of the second replacement indicator groove 124 is located below the lower end 54a of the cutting blade shaft 54 and the lower end 48a of the nut member 48. Therefore, the user can know that it is time to replace the grounding member 46 when the shape of the replacement indicator groove 120 along the outer peripheral surface 72a of the main body 72 changes from an elongated hole shape to a circular shape. Therefore, the user can replace the grounding member 46 before the cutting blade shaft 54 or the nut member 48 comes into contact with the ground P1. As a result, the cutting blade shaft 54 and the nut member 48 can be prevented from wearing down.

[0043] 1, the brush cutter 2 includes an operating rod 12, a cutting blade shaft 54 provided on a front portion 12a of the operating rod 12, a cutting blade 44 attached to the cutting blade shaft 54, and a grounding body 46 attached to the cutting blade shaft 54 below the cutting blade 44 and grounded on the ground P1. The grounding body 46 includes a lower end portion (an example of a "grounding portion") of a second cylindrical portion 100 that grounds on the ground P1, a flange outer peripheral surface 104a (an example of a "curved portion") of a flange portion 104 having a curved shape that extends radially outward and upward from the lower end portion of the second cylindrical portion 100, and a replacement indicator groove portion 120 (an example of a "groove portion") at least a portion of which is provided in the flange outer peripheral surface 104a. The exchange indicator groove 120 has a first exchange indicator groove 122 (an example of a "first groove") having a circumferentially extending elongated hole shape (an example of a "first shape"), and a second exchange indicator groove 124 (an example of a "second groove") having a circular shape and communicating with the first exchange indicator groove 122. The upper end of the second exchange indicator groove 124 is located above the upper end of the first exchange indicator groove 122.

[0044] As the main body 72 of the grounding bar 46 wears, the shape of the replacement indicator groove 120 along the outer circumferential surface 72a of the main body 72 changes from an elongated hole shape to a circular shape. When the shape of the replacement indicator groove 120 changes from an elongated hole shape to a circular shape, the user knows that it is time to replace the grounding bar 46. Therefore, the grounding bar 46 is replaced before a through hole is formed in the main body 72. This reduces the possibility of damage to the grounding bar 46 and notifies the user when it is time to replace the grounding bar 46.

[0045] (First Modification) The replacement indicator groove 120 may not be provided on the lower surface 100a of the second cylindrical portion 100, and the replacement indicator groove 120 may be entirely provided on the flange outer circumferential surface 104a.

[0046] (Second Modification) The outer circumferential surface 72a of the main body 72 does not have to be parallel to the ground surface P1. In this modification, the flange 104 extends radially outward from the lower end of the second cylindrical portion 100. In this modification, the entire replacement indicator groove 120 is provided on the outer circumferential surface 104a of the flange.

[0047] (Third Modification) When the grounding body 46 is viewed from below, the area of the second change indication groove portion 124 may be larger than the area of the first change indication groove portion 122. In this modification, before the main body portion 72 is worn, when the grounding body 46 is viewed from below, the shape of the second change indication groove portion 124 cannot be seen from the outside.

[0048] (Fourth Modification) The shape of the first replacement indicator groove 122 is a shape having a longitudinal direction along the circumferential direction. The shape of the second exchange display groove portion 124 is not limited to a circle, but may be a rectangle, a circle, an ellipse, etc. Furthermore, the shape of the second exchange display groove portion 124 is not limited to a circle, but may be a shape having a longitudinal direction along the circumferential direction, a rectangle, an ellipse, etc.

[0049] (Fifth Modification) The grounding body 46 may have only one replacement indicator groove 120. In another modification, the grounding body 46 may have two replacement indicator grooves 120, or four or more replacement indicator grooves 120.

[0050] (Sixth Modification) The shapes of the plurality of replacement indicator grooves 120 may be different from one another.

[0051] (Seventh Modification) The positions of the plurality of replacement indicator grooves 120 in the up-down direction may be different from one another. [Explanation of symbols]

[0052] 2: Grass cutter 10: Cutting blade unit 12: Operating rod 12a: Front 12b: rear 14: Rear housing 20: Loop handle 22: Grip 24: Lock-off lever 26: Start switch 28: Transmission shaft 30: Power wiring 32: Connector 40: Gear housing 40a: Insertion hole 40b:Aperture 42: Safety cover 44:Kariblade 46: Ground body 48: Nut material 48a: Bottom end 50: 1st gear 52: 2nd gear 54: Cutting blade shaft 54a: Bottom end 60: Transmission section 60a: First cylindrical part 60b: First disc part 62: Metal fittings 70: Mounting part 72: Main body 72a: Outer surface of main body 80: Inner mounting part 82:Outside mounting part 84: Second disc part 84a: 1st through hole 86:Cylinder part 86a: Arc section 86b: Flat part 88: Connection 90: Radial extension part 92: Axial extension part 94: 1st concave groove 100: Second cylindrical part 100a: Bottom surface 102:Fixed part 104: Flange part 104a: Flange outer surface 106: Third cylindrical section 108: 4th cylindrical section 108a: Cylinder outer surface 109:Second concave groove 110: Third disc 110a: 2nd through hole 112: 4th disc 112a: opening 114: Fixed groove 120: Replacement display groove 122: 1st replacement display groove 124: 2nd replacement display groove A: Axis H1: Height H2: Height P1: Ground

Claims

1. A grounding body attached to a cutting blade shaft of a grass cutter, a grounding portion that contacts the ground; a curved surface portion having a curved shape extending radially outward and upward from the ground contact portion; a groove portion, at least a part of which is provided on the curved surface portion, the groove portion includes a first groove portion having a first shape and a second groove portion communicating with the first groove portion and having a second shape different from the first shape, The upper end of the second groove portion is located higher than the upper end of the first groove portion. Grounding body.

2. The grounding body according to claim 1 , wherein the second groove portion is disposed inside the first groove portion when the grounding body is viewed from below.

3. When the grounding body is viewed from below, The first groove portion has a shape having a longitudinal direction along the circumferential direction, The grounding element according to claim 2 , wherein the second groove portion has a circular shape.

4. The grounding body further includes a plurality of the grooves, The grounding member according to claim 1 , wherein the plurality of grooves are arranged at equal intervals in the circumferential direction.

5. The grounding body further includes: a mounting portion for mounting the grounding body to the cutting blade shaft; a main body portion having the grounding portion, the curved surface portion, and the groove portion, The grounding body is attached to the cutting blade shaft by a nut member, The attachment portion has a through hole through which the cutting blade shaft passes, The grounding member according to claim 1 , wherein an upper end of the second groove portion is located lower than a lower end of the cutting blade shaft and a lower end of the nut member.

6. An operating rod and a cutting blade shaft provided at the front of the operating rod; a cutting blade attached to the cutting blade shaft; a grounding body attached to the blade shaft below the blade and adapted to contact the ground, The grounding body is a grounding portion that contacts the ground; a curved surface portion having a curved shape extending radially outward and upward from the ground contact portion; a groove portion, at least a part of which is provided on the curved surface portion; the groove portion includes a first groove portion having a first shape and a second groove portion communicating with the first groove portion and having a second shape different from the first shape, The upper end of the second groove portion is located higher than the upper end of the first groove portion. Lawnmower.

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