IMPLEMENT

Description

TECHNICAL FIELD

The present disclosure relates to an implement such as a backhoe. The present application claims priority based on Japanese Patent Application No. 2023-142896 filed on Sep. 4, 2023, the entire contents of which are incorporated herein by reference.

BACKGROUND ART

In a backhoe that is an excavator, an excavation device is attached to a machine body mounted on a traveling device to be swingable up and down, and excavation and the like of the ground are performed by the excavation device (see, for example, PATENT LITERATURE 1). A boom included in an excavation device includes a main body that is a long structural body bent in a substantially dogleg shape, and a coupling body that is provided at the end of the main body in a longitudinal direction and to which a rotating shaft is attached. The coupling body has a hollow shape for weight reduction and the like, and the inside of the hollow is opened in a surface facing the main body of the boom.

Citation List

Patent Literature

• • PATENT LITERATURE 1: Japanese Laid-Open Patent Publication No. 2004-176312

SUMMARY OF THE INVENTION

An implement of the present disclosure includes: a machine body; and a work device attached to the machine body, in which the work device includes a swing member swingable about a shaft as a fulcrum, the swing member includes a main body and a coupling body coupled to an end portion of the main body and to which the shaft is attached, the coupling body has a hollow shape, and has an opening that opens an inside of the coupling body in an end surface on the main body side, and the swing member further includes a lid body that closes the opening.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic side view illustrating an overall configuration of an implement according to an embodiment.

FIG. 2 is a perspective view of a boom of the work device.

FIG. 3 is a perspective view illustrating a part of the boom.

FIG. 4 is an exploded perspective view of a part of the boom.

FIG. 5 is a cross-sectional view taken along line D-D in FIG. 4.

FIG. 6 is a perspective view of the periphery of the opening of the coupling body.

FIG. 7 is a perspective view of the coupling body to which a lid body is attached.

FIG. 8 is a perspective view of a part of the boom before a fourth plate member is attached.

FIG. 9 is a view in a direction of an arrow E in FIG. 8.

FIG. 10 is a cross-sectional view taken along line B-B in FIG. 3.

FIG. 11 is a view in a direction of an arrow C in FIG. 3.

DETAILED DESCRIPTION

Problems to Be Solved by Present Disclosure

Since a load such as bending or twisting is applied to a coupling body of a boom by work such as excavation, it is required to increase rigidity in order to resist the load while reducing the weight. An object of the present disclosure is to increase rigidity of a coupling body provided at an end of a swing member that is a component of a work device.

Effects of Present Disclosure

The present disclosure can increase rigidity of a coupling body provided at an end of a swing member that is a component of a work device.

Outline of Embodiment of Present Disclosure

Hereinafter, aspects of an embodiment of the present disclosure will be listed and described.

(1) An implement of the embodiment of the present disclosure includes: a machine body; and a work device attached to the machine body, the work device includes a swing member swingable about a shaft as a fulcrum, the swing member includes a main body and a coupling body coupled to an end portion of the main body and to which the shaft is attached, the coupling body has a hollow shape, and has an opening that opens an inside of the coupling body in an end surface on the main body side, and the swing member further includes a lid body that closes the opening.

(2) In the implement of (1), at least a part of an outer peripheral portion of the lid body is joined to an inner peripheral surface of the opening.

(3) In the implement of (2), another part of the outer peripheral portion of the lid body is joined to an end surface of the coupling body on the main body side.

(4) In the implement according to any one of (1) to (3), an inner peripheral surface of the opening includes a groove that extends in a circumferential direction of the opening and into which the lid body is inserted.

(5) In the implement according to (3), the inner peripheral surface of the opening includes a groove extending in a circumferential direction of the opening and into which the outer peripheral portion of the lid body is inserted, the groove is formed at a position corresponding to the part of the outer peripheral portion of the lid body, and the coupling body has a cutout portion that opens the groove to an outside at a position corresponding to the other part of the outer peripheral portion of the lid body.

(6) In the implement according to any one of (1) to (5), the main body has a hollow shape, the swing member includes a first joint portion that joins an outer surface of the main body and the coupling body, and a second joint portion that joins an inner surface of the main body and the coupling body, and a communication port for connecting the first joint portion and the second joint portion is formed in the main body.

(7) In the implement according to any one of (1) to (6), the coupling body includes a pair of support portions that support the shaft, and a space is formed between the pair of support portions.

Details of Embodiment of Present Disclosure

Overall Configuration of Implement

FIG. 1 is a schematic side view illustrating an overall configuration of an implement according to an embodiment.

An implement 10 of the present embodiment is an excavator exemplified by a backhoe. The implement 10 includes a machine body (turning table) 12, a traveling device 13, and a work device 14. The machine body 12 is provided with a driver's seat and a cabin 15 surrounding the driver's seat. Instead of the cabin 15, the machine body 12 may be provided with a canopy that covers the upper side of the driver's seat.

In the description of the overall configuration of the implement 10, a direction toward the front side of the operator seated in the driver's seat of the implement 10 (a direction of an arrow A1 in FIG. 1) is also referred to as forward, and the opposite direction (a direction of an arrow A2 in FIG. 1) is also referred to as rearward. A direction toward the left side of the operator (a direction toward front of the paper of FIG. 1) is also referred to as a left direction, and a direction toward the right side of the operator (a direction toward back of the paper of FIG. 1) is also referred to as a right direction.

As illustrated in FIG. 1, the traveling device 13 supports the machine body 12 in a travelable manner. The traveling device 13 of the present embodiment is a crawler traveling device, and includes a traveling frame 13A and crawler traveling bodies 13B provided on both left and right sides of the traveling frame 13A. The traveling bodies 13B are driven by a traveling motor M1 provided on the traveling frame 13A, which is operated by hydraulic pressure. A dozer device 17 is provided at a front portion or a rear portion of the traveling frame 13A. The traveling device 13 may include wheel traveling bodies instead of the crawler traveling bodies 13B.

The machine body 12 is supported on the traveling device 13 via a turning bearing 18. The machine body 12 is rotatable about an axis O extending in the up-down direction by the turning bearing 18. The machine body 12 includes a support bracket 19 and a swing bracket 20 that support the work device 14 at a front portion. The support bracket 19 protrudes forward from the machine body 12. The swing bracket 20 is connected to a front portion of the support bracket 19 via a vertical shaft 20A. The vertical shaft 20A has an axis extending in the up-down direction. The swing bracket 20 is swingable in the left-right direction about the axis of the vertical shaft 20A. The swing bracket 20 swings by extension and contraction of a swing cylinder (not illustrated) provided in the machine body 12.

The work device 14 of the present embodiment is an excavation device. The work device 14 includes a boom 21, an arm 22, and a bucket 23. A base portion of the boom 21 is connected to an upper portion of the swing bracket 20 via a horizontal shaft 25. The horizontal shaft 25 has an axis extending in the left-right direction. The boom 21 is swingable about the axis of the horizontal shaft 25. The boom 21 swings by extension and contraction of a boom cylinder 61.

The arm 22 is connected to the distal end side of the boom 21 via a horizontal shaft 26. The horizontal shaft 26 has an axis extending in the left-right direction. The arm 22 is swingable about the axis of the horizontal shaft 26. The arm 22 swings by extension and contraction of an arm cylinder 62.

The bucket 23 is provided on the distal end side of the arm 22 so as to be able to perform a scooping operation and a dumping operation. The scooping operation is an operation of swinging the bucket 23 in a direction of approaching the boom 21, and is, for example, an operation of scooping earth and sand, or the like. The dumping operation is an operation of swinging the bucket 23 in a direction away from the boom 21, and is, for example, an operation of dropping (discharging) the scooped earth and sand. The bucket 23 performs a scooping operation and a dumping operation by extension and contraction of a bucket cylinder 63.

The swing cylinder, the boom cylinder 61, the arm cylinder 62, and the bucket cylinder 63 are configured by a hydraulic cylinder (hydraulic actuator). The work device 14 may include other work tools instead of or in addition to the bucket 23. For example, the work device 14 may include a hydraulic breaker, a hydraulic crusher, an angle broom, an earth auger, a pallet fork, a sweeper, a mower, or a snow blower.

Configuration of Boom

FIG. 2 is a perspective view of the boom of the work device.

As illustrated in FIG. 1 and FIG. 2, the boom (swing member) 21 has a substantially dogleg shape (boomerang shape; L-shape) in a side view. The boom 21 includes a main body 31 and coupling bodies 32 and 33. The main body 31 is a long structure and is a most part of the boom 21. The coupling bodies 32 and 33 are provided at both ends of the main body 31 in the longitudinal direction. One coupling body 32 is coupled to the swing bracket 20 of the machine body 12 via the horizontal shaft 25. The other coupling body 33 is coupled to one end of the arm 22 via the horizontal shaft 26.

FIG. 3 is a perspective view illustrating a part of the boom. FIG. 4 is an exploded perspective view of a part of the boom. FIG. 3 and FIG. 4 illustrate the coupling body 32 coupled to the swing bracket 20 and a part of the main body 31 connected to the coupling body 32. In FIG. 3 and FIG. 4, arrows indicating a first direction X, a second direction Y, and a third direction Z orthogonal to each other are illustrated. In the following description of the boom 21, for convenience, the first direction X is defined as the left-right direction, the second direction Y is defined as the front-rear direction, and the third direction Z is defined as the up-down direction.

The main body 31 of the boom 21 is formed to have a cylindrical shape (hollow shape) by joining a plurality of components 41 to 44. Specifically, the main body 31 is formed in a rectangular tube shape by joining the first to fourth plate members 41 to 44. The first plate member 41 and the second plate member 42 are arranged to face each other with a space therebetween in the left-right direction X. The third plate member 43 and the fourth plate member 44 are arranged to face each other with a space therebetween in the up-down direction Z. The upper ends of the first and second plate members 41 and 42 are joined to the lower surface of the fourth plate member 44. The lower ends of the first and second plate members 41 and 42 are joined to the upper surface of the third plate member 43.

The coupling body 32 is a cast product of cast steel, cast iron, or the like. The coupling body 32 includes a body portion 35 disposed on the front side (main body 31 side) and support portions 36 disposed on the rear side (the side opposite to the main body 31). The body portion 35 is the main portion of the coupling body 32. A front end portion 35A of the body portion 35 has a substantially quadrangular outer peripheral surface. The first to fourth plate members 41 to 44 included in the main body 31 are joined in a state of being in contact with the respective surfaces on the periphery of the end portion 35A of the body portion 35.

FIG. 5 is a cross-sectional view taken along line D-D in FIG. 4. FIG. 6 is a perspective view of the periphery of the opening of the coupling body.

The body portion 35 has a hollow shape. An inside portion (hollow portion) 37 of the body portion 35 is closed in the left-right direction X, the up-down direction Z, and rearward, and is opened forward. Specifically, the inside portion 37 of the body portion 35 is opened to the main body 31 side through an opening 38 formed in the front end surfaces 35A1 and 35A2 of the coupling body 32. The opening 38 is formed in a substantially quadrangular shape similarly to the outer peripheral surface of the end portion 35A of the body portion 35.

A groove 51 is formed in the inner peripheral surfaces of the opening 38. The groove 51 extends in the circumferential direction of the opening 38. The groove 51 is formed in three of the inner peripheral surfaces of the opening 38 that are inner surfaces on both sides in the left-right direction X and an inner surface on a lower side. The groove 51 has a bottom surface 51b and a side surface 51a. The bottom surface 51b of the groove 51 faces the inner peripheral side of the opening 38 and substantially serves as the inner peripheral surface of the opening 38. The groove 51 is opened forward. The side surface 51a of the groove 51 is formed along the rear end edge of the bottom surface 51b. The side surface 51a of the groove 51 is a surface facing forward.

The end portion 35A of the body portion 35 of the coupling body 32 has a portion (cutout portion 35B) cut out in an angular C shape (U shape) in a top view in an upper portion. The cutout portion 35B has a substantially rectangular shape elongated in the left-right direction X. The width d of the cutout portion 35B in the front-rear direction is the same as the width d of the groove 51 in the front-rear direction Y. The cutout portion 35B is provided in a range corresponding to a space between one end and the other end of the groove 51 in the circumferential direction of the opening 38. The groove 51 is opened upward by the cutout portion 35B.

The front end surface of the body portion 35 includes a first end surface 35A1 disposed on both sides of the opening 38 in the left-right direction X and on the lower side, and a second end surface 35A2 disposed on the upper side of the opening 38. The second end surface 35A2 is an end surface on the rear side of the cutout portion 35B. The second end surface 35A2 is located on the rear of the first end surface 35A1. The second end surface 35A2 is disposed on the same plane as the side surface 51a of the groove 51.

FIG. 7 is a perspective view of a coupling body to which a lid body is attached. FIG. 8 is a perspective view of a part of the boom before the fourth plate member 44 is attached. FIG. 9 is a view in a direction of an arrow E in FIG. 8. FIG. 10 is a cross-sectional view taken along line B-B in FIG. 3.

As illustrated in FIG. 4 and FIG. 7, the boom 21 of the present embodiment further includes a lid body 55 that closes the opening 38 of the coupling body 32. The lid body 55 is made of a plate member having a substantially quadrangular plate surface. A length L1 of lid body 55 in the left-right direction X is slightly smaller than a distance L3 (see FIG. 5) between the bottom surfaces 51b of the groove 51 on both left and right sides of the opening 38. A length L2 of the lid body 55 in the up-down direction is larger than a distance L4 (see FIG. 5) between the bottom surface 51b of the groove 51 on the lower side of the opening 38 and the inner peripheral surface of the opening 38 on the upper side, and is smaller than a distance L5 (see FIG. 5) between the bottom surface 51b of the groove 51 on the lower side of the opening 38 and an upper surface 35A3 of the end portion 35A of the body portion 35. The thickness t of the lid body 55 is smaller than the width d of the groove 51 in the front-rear direction Y.

The lid body 55 is fitted into the groove 51. The lid body 55 is disposed in a space surrounded by the bottom surface 51b of the groove 51. Outer peripheral surfaces of the lid body 55 on both sides in the left-right direction X and the lower side are arranged to face the bottom surface 51b of the groove 51. The plate surface of the lid body 55 on the rear side (rear surface) is arranged to face the side surface 51a of the groove 51 and the second end surface 35A2. The lid body 55 is positioned in the front-rear direction Y by coming into contact with the side surface 51a of the groove 51 and the second end surface 35A2.

As illustrated in FIG. 10, the lid body 55 is joined to the body portion 35 of the coupling body 32 by welding. Specifically, the outer peripheral portions of the front surface of the lid body 55 on both sides in the left-right direction X and the lower side are joined to the bottom surface 51b of the groove 51 by welding. In the present specification, a portion joined by this welding is denoted by reference numeral W1, and is expressed as a weld W1 or a joint portion W1. Hereinafter, other welds are similarly expressed.

The outer peripheral surface of the lid body 55 on the upper side and the second end surface 35A2 of the body portion 35 are joined by a weld W2. Therefore, the entire periphery of the outer peripheral portion of the lid body 55 is joined to the body portion 35 of the coupling body 32, and is firmly fixed to the body portion 35.

The welds W1 and W2 of the lid body 55 to the coupling body 32 as described above are welding from the inside in the left-right direction X as indicated by an arrow a in FIG. 9 or welding from the upper side as indicated by an arrow b. Therefore, as illustrated in FIG. 8, the welds W1 and W2 of the lid body 55 to the coupling body 32 can be performed from above even in a state where the first to third plate members 41 to 43 of the main body 31 are joined to the coupling body 32.

FIG. 9 and FIG. 10 also illustrate the welds W1 and W2 between the coupling body 32 and the lid body 55, welds W3 and W4 in the main body 31, and welds W5, W6, and W7 between the main body 31 and the coupling body 32. Both surfaces of the lower ends of the first and second plate members 41 and 42 included in the main body 31 and the upper surface of the third plate member 43 are joined by the weld W3. The outer surfaces of the upper ends of the first and second plate members 41 and 42 and the lower surface of the fourth plate member 44 are joined by the weld W4. The first end surface 35A1 of the coupling body 32 and the inner surfaces of the first to third plate members 41 to 43 are joined by the weld W5. The rear end surfaces of the first and second plate members 41 and 42 and the side surfaces of the end portion 35A of the coupling body 32 in the left-right direction X are joined by the weld W6 (see FIG. 9). The weld W5 joins an inner surface of the main body 31 (a surface located inside the main body 31 having a hollow shape) and the coupling body 32.

FIG. 11 is a view in a direction of an arrow C in FIG. 3.

As illustrated in FIG. 4, FIG. 8, and FIG. 11, a cutout 57 is formed in the upper surface at the rear end of each of the first and second plate members 41 and 42. The cutout 57 has a shape elongated in the front-rear direction. The cutout 57 is open upward and backward. As illustrated in FIG. 11, a lower edge 57a of the cutout 57 extends linearly in the front-rear direction. A front edge 57b of the cutout 57 is inclined forward from bottom to top. Due to the inclination of the front edge 57b, a substantially triangular opening H is formed between the first end surface 35A1 of the coupling body 32, the front edge 57b of the cutout 57, and the lower surface of the fourth plate member 44. A side surface of the end portion 35A of the coupling body 32 is exposed to the outside in the left-right direction X by the cutout 57. Note that the opening H does not have to have a triangular shape, and may be a quadrangular shape, a semicircular shape, or the like, and the shape is not particularly limited.

The lower edge 57a of the cutout 57 in each of the first and second plate members 41 and 42 and the side surface of the end portion 35A of the coupling body 32 are joined by the weld W7. The weld W7 is connected to the weld W6 that joins the rear end surfaces of the first and second plate members 41 and 42 and the side surface of the end portion 35A of the coupling body 32, and the weld W7 and the weld W6 are continuous. The welds W6 and W7 join the outer surface of the hollow main body 31 (surface located outside the main body 31 having a hollow shape) and the coupling body 32.

The rear end surface of the fourth plate member 44 and the upper surface 35A3 of the end portion 35A of the coupling body 32 are joined by a weld W9. The lower surface of the fourth plate member 44 and the side surface of the end portion 35A of the coupling body 32 are joined by a weld W8. The weld W9 and the weld W8 are connected to each other and are continuous. The welds W8 and W9 join the outer surface of the main body 31 and the coupling body 32. The cutout 57 formed in the first and second plate members 41 and 42 can make the weld W8 longer, and thus the fourth plate member 44 and the coupling body 32 can be more firmly joined.

In FIG. 11, the welds W7 and W8 for joining the outer surface of the main body 31 and the coupling body 32 are connected to a weld W5 for joining the inner surface of the main body 31 and the coupling body 32 at the opening H, and the welds W7 and W8 and the weld W5 are continuous. In addition, the welds W7 and W8 and the weld W5 are connected to the weld W4 at the opening H, and the welds W7 and W8, the weld W5, and the weld W4 are continuous. By continuing the welds through the opening H as described above, it is possible to suppress disconnection of the welding in the middle, reduce end portions of the welding where stress concentration is likely to occur, and suppress a defect at the joint portion. When the manufacturing of the boom 21 is completed, the opening H is entirely closed by the welding material connecting the welds W7, W8, W4, and W5.

As illustrated in FIG. 3, the support portions 36 of the coupling body 32 protrude from the body portion 35 to the rear side (the side opposite to the main body 31). The support portions 36 in pair are provided at an interval in the left-right direction X. A space S is formed between the left and right support portions 36. A boss 36A having a cylindrical shape is provided at a distal end (rear end) of the support portion 36. The horizontal shaft 25 is inserted into and attached to the boss 36A.

A hydraulic hose or the like drawn out from the machine body 12 and connected to the hydraulic cylinders 62 and 63 passes through the space S (space above the horizontal shaft 25 in FIG. 1) of the coupling body 32. Therefore, as compared with the case where the hydraulic hose or the like is passed through the lower side of the horizontal shaft 25, it is possible to suppress rearward protrusion of the hose or the like when the boom 21 is swung upward (rearward) and to suppress contact of the hose with the cabin 15.

Operation and Effect of Embodiment

(1) In the above-described embodiment, an implement 10 includes a machine body 12 and a work device 14 attached to the machine body 12. The work device 14 includes a swing member (boom) 21 swingable about a shaft (horizontal shaft) 25 as a fulcrum. The swing member 21 includes a main body 31 and a coupling body 32 coupled to an end portion of the main body 31 and to which the shaft 25 is attached. The coupling body 32 has a hollow shape, and has an opening 38 that opens an inside of the coupling body in an end surface 35A1 on the main body 31 side. The swing member 21 further includes a lid body 55 that closes the opening 38.

According to the above-described configuration, the coupling body 32 that has a hollow shape is reinforced by the lid body 55. Therefore, the rigidity of the coupling body 32 is increased, and strain due to a load such as bending or twisting can be suppressed.

(2) In the above-described embodiment, at least a part of an outer peripheral portion of the lid body 55 is joined to an inner peripheral surface of the opening 38 (the bottom surface 51b of the groove 51). According to the above-described configuration, the lid body 55 can be easily joined to the coupling body 32 by welding. In particular, in the above-described embodiment, even in a state where the left and right plate members 41 and 42 and the lower plate member 43 of the main body 31 are joined to the coupling body 32, the outer peripheral portions on the left and right sides and the lower side of the lid body 55 can be joined to the coupling body 32 inside the main body 31 surrounded by the plate members 41, 42, and 43.

(3) In the above-described embodiment, another part of the outer peripheral portion of the lid body 55 is joined to an end surface 35A2 of the coupling body 32 on the main body 31 side (front side). Therefore, even in a state where the left and right plate members 41 and 42 and the lower plate member 43 of the main body 31 are joined to the coupling body 32 as in the above-described embodiment, the upper outer peripheral portion of the lid body 55 can be easily joined to the coupling body 32.

(4) In the above-described embodiment, an inner peripheral surface of the opening 38 includes a groove 51 that extends in a circumferential direction of the opening 38 and into which the lid body 55 is inserted. According to the above-described configuration, the outer peripheral portion of the lid body 55 described above and the inner peripheral surface 51b of the opening 38 can be joined to each other.

(5) In the above-described embodiment, the groove 51 is formed at a position corresponding to the part of the outer peripheral portion of the lid body 55, and the coupling body 32 has a cutout portion 35B that opens the groove 51 to an outside at a position corresponding to the other part of the outer peripheral portion of the lid body 55. According to the above-described configuration, the lid body 55 can be inserted into the groove 51 through the cutout portion 35B, and the outer peripheral portion of the lid body 55 as described above and the end surface 35A2 of the coupling body 32 can be joined.

(6) In the above-described embodiment, the main body 31 has a hollow shape. The swing member 21 includes first joint portions (welds W7 and W8) that join the outer surface of the main body 31 and the coupling body 32, and a second joint portion (weld W5) that joins the inner surface of the main body 31 and the coupling body 32. In the main body 31, a communication port (opening H) for connecting the first joint portions W7 and W8 and the second joint portion W5 is formed. Therefore, the first joint portions W7 and W8 outside the main body 31 and the second joint portion W5 inside the main body can be continued via the communication port H, and the end portions of the joint portion where the stress concentration is likely to occur can be reduced, and a defect of the joint portion can be suppressed.

(7) In the above-described embodiment, the coupling body 32 includes the pair of support portions 36 that support the shaft 25, and the space S is formed between the pair of support portions 36. By making a hose or the like drawn out from the machine body 12 and connected to the hydraulic cylinders 62 and 63 pass through the space S, the amount of movement of the hose or the like accompanying the swinging of the swing member 21 can be suppressed.

Although the embodiment has been described above, it should be appreciated that various changes in form and details can be made without departing from the spirit and scope of the claims.

For example, the structure of the coupling body 32 of the boom 21 as described above may be applied to the coupling body 33 at the other end of the boom 21. Similarly to the boom 21, the arm 22 includes a main body and a coupling body, and the structure of the coupling body 32 described above may be applied to the coupling body. That is, the swing member of the present disclosure may be the boom 21 or the arm 22. The implement of the present disclosure does not have to be a backhoe, and is not particularly limited as long as the implement includes a work device including a swing member swingable about a shaft as a fulcrum.

The groove 51 of the coupling body 32 may be formed not to open forward and has a substantially C-shape cross section having front and rear side surfaces. In this case, for example, the lid body 55 can be attached by inserting the lid body 55 into the groove 51 from the cutout portion 35B in the upper portion of the coupling body 32.

The cutout portion 35B is not necessarily formed in the coupling body 32. The groove 51 may be formed in the entire inner peripheral surface of the opening 38. The groove 51 is not necessarily formed in the coupling body 32. In either case, the lid body 55 can be inserted into the opening 38 from the front side of the coupling body 32, and the outer peripheral portion of the lid body 55 can be joined to the inner peripheral surface of the opening 38.

The coupling body 32 does not have to be a cast product, and may be formed by joining a plurality of components such as plate members. The support portions 36 of the coupling body 32 are not necessarily in pair, and the space S is not necessarily formed. For example, the support portion 36 of the coupling body 32 may include a single boss 36A that is long in the left-right direction X into which the most part of the horizontal shaft 25 is inserted.

Reference Signs List

• • 10 implement
  • 12 machine body
  • 14 work device
  • 21 boom (swing member)
  • 25 horizontal shaft
  • 31 main body
  • 32 coupling body
  • 35A end portion
  • 35A1 end surface
  • 35A2 end surface
  • 35B cutout portion
  • 36 support portion
  • 38 opening
  • 51 groove
  • 51b bottom surface (inner peripheral surface of opening)
  • 55 lid body
  • H opening (communication port)
  • W5 weld (second joint portion)
  • W6 weld (first joint portion)
  • W8 weld (first joint portion)