Work machinery and work attachments

Abstract

The present invention provides a work machine that allows for easy alignment of the pin holes when connecting the front boom and the main boom, and eliminates the need for a dedicated support frame for the arm's ground contact point. [Solution] The present invention relates to a work machine 1 having a base machine 2, a main boom 5, and a work attachment 6. The work attachment 6 includes a front boom 7 and an arm 9, and can be folded. In the folded state, the arm 9 includes a tip portion 9a, an arm base portion 9b, and a lower surface 15. The arm 9 includes a first grounding portion 11 disposed on the lower surface 15 and having a grounding surface that protrudes downward, and a second grounding portion 12 disposed on the lower surface 15 so as to be located closer to the arm base portion 9b than the first grounding portion 11 and protruding downward, and having a grounding surface that is located above the grounding surface of the first grounding portion 11.

Description

Technical Field

[0001] The present invention relates to a working machine and a working attachment attached thereto.

Background Art

[0002] For example, Patent Document 1 below proposes a support method and a support device for a front member (front boom and arm) of a working attachment that is detachable from the main boom of a working machine. As shown in this Patent Document 1, conventionally, with the working attachment supported by such a support device, they are transported, or the working attachment and the main boom of the base machine are connected.

[0003] Also, Patent Document 2 below proposes providing a grounding tool on the upper surface of the base end portion of an arm as means for supporting the tip end portion of the working attachment during the above-described connection operation. This grounding tool grounds only at the lifting stage where the engagement portion between the front boom and the main boom is lifted, and can serve as a fulcrum when a rotational moment in the toppling direction acts on the working attachment. The working machine of Patent Document 2 can easily perform pin hole alignment between the front boom and the main boom during the connection operation of these by such a grounding tool.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] When the work attachment described in Patent Document 2 is placed on the ground via such cushioning material, it becomes difficult to make contact with the ground using the aforementioned grounding device as a fulcrum. For this reason, it becomes necessary to provide a separate, dedicated support stand below the grounding device. However, if the grounding device is to be placed on such a dedicated support stand using the grounding device as a fulcrum, the support stand may shift, and the outer surface of the arm may collide with the ground.

[0007] Furthermore, one possible solution is to make the aforementioned support structure sufficiently large; however, preparing and storing such a structure is cumbersome, and improvement is needed.

[0008] This invention was devised in view of the above-described circumstances, and its main objective is to provide a work machine and work attachment that allows for easy alignment of the pin holes when connecting the front boom and the main boom, and that does not require a dedicated frame for the arm's ground contact portion. [Means for solving the problem]

[0009] A first aspect of the present invention is a work machine comprising a self-propelled base machine, a main boom mounted to the base machine in a luffable manner, and a work attachment detachably attached to the main boom, wherein the work attachment includes a front boom having a base end connected to the main boom, and an arm positioned on the front end side of the work attachment than the front boom, and can assume a folded state in which the front boom and the arm face each other when the front boom is extended horizontally and the arm is extended horizontally below the front boom, and in the folded state, the arm includes a longitudinal tip, an arm base end which is the end opposite to the tip, and a lower surface facing downward between the tip and the arm base end, and the arm includes a first grounding portion positioned on the lower surface and having a grounding surface that protrudes downward, and a second grounding portion positioned on the lower surface so as to be closer to the arm base end than the first grounding portion and protruding downward, and having a grounding surface that is located above the grounding surface of the first grounding portion.

[0010] In the work machine of the present invention, when assembling the attachment to connect the front boom of the folded work attachment to the main boom, it is desirable that the first ground contact portion lifts off the ground when the base end of the front boom is lifted by making contact with the ground using the second ground contact portion as a fulcrum.

[0011] In the work machine of the present invention, it is desirable that the contact surface of the first grounding portion extends along the lower surface.

[0012] In the work machine of the present invention, it is desirable that the contact surface of the first grounding portion has a series of inclined surfaces on the tip side that are inclined toward the lower surface toward the tip side.

[0013] In the work machine of the present invention, it is desirable that the contact surface of the second contact portion has a curved contour when viewed from the side of the arm.

[0014] In the work machine of the present invention, the first ground contact portion is composed of a plate-shaped member extending along the lower surface and is supported by a plurality of plate-shaped support members extending in a direction perpendicular to the plate-shaped member, and it is desirable that a part of the plate-shaped support members constitutes the second ground contact portion.

[0015] In the working machine of the present invention, it is desirable that the width of the contact surface of the first contact portion is greater than the width of the contact surface of the second contact portion.

[0016] A second aspect of the present invention is a work attachment that is detachably attached to a main boom of a work machine, comprising a front boom having a base end connected to the main boom, and an arm positioned on the front end side of the work attachment than the front boom, wherein the front boom can be folded so that the front boom and the arm face each other when the front boom is extended horizontally and the arm is extended horizontally below the front boom, and in the folded state, the arm comprises a longitudinal tip, an arm base end which is the end opposite to the tip, and a lower surface facing downward between the tip and the arm base end, and the arm comprises a first grounding portion positioned on the lower surface and having a grounding surface that protrudes downward, and a second grounding portion positioned on the lower surface so as to be closer to the arm base end than the first grounding portion and protruding downward, and having a grounding surface that is located above the grounding surface of the first grounding portion. [Effects of the Invention]

[0017] By adopting the above-mentioned features, the work machine and work attachment of the present invention make it easy to align the pin holes of the front boom and the main boom when connecting them, and eliminate the need for a dedicated frame for the arm's ground contact portion. [Brief explanation of the drawing]

[0018] [Figure 1] This is a side view of the work machine of this embodiment. [Figure 2]It is an enlarged view of the working attachment of FIG. 1. [Figure 3] It is a perspective view of the inclined surface on the base end side of the arm of FIG. 2. [Figure 4] (a) is an enlarged view when the first grounding portion is grounded, and (b) is an enlarged view when the second grounding portion is grounded. [Figure 5] It is a schematic view when observing the first grounding portion and the second grounding portion from the front. [Figure 6] It is a front view of the first grounding portion. [Figure 7] It is a perspective view of the first grounding portion and the second grounding portion of another embodiment of the present invention.

Mode for Carrying Out the Invention

[0019] Hereinafter, an embodiment of the present invention will be described based on the drawings. Although the drawings include the features of the present invention, in order to assist in understanding the present invention, there may be exaggerated expressions or expressions different from the actual structural dimensional ratios. Also, throughout each embodiment, the same or common elements are denoted by the same reference numerals, and duplicate descriptions are omitted. In addition, well-known configurations can be appropriately adopted for configurations not described in this specification.

[0020] FIG. 1 is a side view of the working machine 1 of the present embodiment. In each figure of this specification, the directions are indicated by arrows. As shown in FIG. 1, the arrow Up indicates the upper side. The arrow Dw indicates the lower side. The arrow Fw indicates the front side in the front-rear direction of the working machine 1. The arrow Rr indicates the rear side in the front-rear direction. Also, in other figures, the left side of the working machine 1 may be indicated by the arrow Lf, and the right side may be indicated by the arrow Rh.

[0021] As shown in Figure 1, the work machine 1 of this embodiment is used, for example, as a demolition machine with an extra-long attachment used for demolishing high-rise buildings. The work machine 1 includes a self-propelled base machine 2, a main boom 5, and a work attachment 6. The base machine 2 includes a lower traveling body 3 that provides driving force and an upper slewing body 4 that is rotatably mounted on the lower traveling body 3. The lower traveling body 3 of this embodiment is of the crawler type, but is not limited to this, and may, for example, provide driving force using multiple tires.

[0022] The main boom 5 is mounted to the base machine 2 in a way that allows it to be raised and lowered. The main boom 5 extends forward from the upper slewing body 4 and can be raised and lowered around the boom foot pin (not shown in the figure).

[0023] The work attachment 6 is detachably attached to the tip of the main boom 5. For example, when the work machine 1 is transported to a work site, the base machine 2, including the main boom 5, and the work attachment 6 are disassembled for transport and assembled at the work site. More specifically, the work attachment 6 includes a front boom 7 having a base end 7a that is connected to the main boom 5, and this front boom 7 is detachably pin-connected to the tip of the main boom 5. This allows the base machine 2 and the work attachment 6 to be assembled.

[0024] Figure 2 shows an enlarged view of the work attachment 6. As shown in Figure 2, the work attachment 6 includes the front boom 7 described above and an arm 9 positioned further forward on the work attachment 6. In this embodiment, the work attachment 6 includes an inter-boom 8 between the front boom 7 and the arm 9. The inter-boom 8 is mounted on the tip of the front boom 7 so as to be rotatable around a horizontal axis. The arm 9 is mounted on the tip of the inter-boom 8 so as to be rotatable around a horizontal axis. For example, a crusher or the like is mounted on the tip portion 9a of the arm 9 (not shown).

[0025] The work attachment 6 can be folded by bending it between the front boom 7 and the arm 9. This folded state means that the front boom 7 is extended horizontally and the arm 9 is extended horizontally below the front boom 7, so that the front boom 7 and the arm 9 face each other. Figure 2 shows the work attachment 6, detached from the base machine 2, placed on the ground G in the folded state described above. The work attachment 6 in Figure 2 is supported by the first ground contact section 11 and the frame St, which will be described later. Although not shown in Figure 2, a link (arm storage link) or the like may be used to connect the front boom 7 and the arm 9 to prevent the arm 9 from sagging and touching the ground due to its own weight.

[0026] In this folded state, the front boom 7 has its rear surface 7bs facing upward and its underside 7fs facing downward. The arm 9 also has its underside 9fs facing upward and opposite the underside 7fs of the front boom 7. Furthermore, the rear surface 9bs of the arm 9 faces downward. The rear surface 7bs of the front boom 7 and the rear surface 9bs of the arm 9 are the surfaces that face upward when the work attachment 6 is fully extended horizontally while mounted on the main boom. The underside 7fs of the front boom 7 and the underside 9fs of the arm 9 are the surfaces that face downward when the attachment is extended horizontally.

[0027] In the work machine 1 of this embodiment, the procedure for connecting the main boom 5 (shown in Figure 1, and the same applies hereinafter) and the front boom 7 is the same as in the conventional method, as follows. First, an upward-opening hook (not shown) separately provided at the tip of the main boom 5 engages with a shaft (not shown) such as a round pin separately provided at the base end 7a of the front boom 7 of the work attachment 6, which is placed in a folded state.

[0028] From this state, the main boom 5 is further lifted, and the front boom 7 is rotated around the aforementioned shaft to align the lower pin holes of the main boom 5 and the front boom 7, and the lower pin is inserted therein. In this way, the main boom 5 and the front boom 7 are connected. For this operation to be carried out smoothly, it is necessary to make it easy to accurately align the pin holes of the main boom 5 and the front boom 7. In other words, it is necessary to make it easy to change the orientation of the work attachment 6 in the sideways direction when the base end 7a of the front boom 7 is lifted.

[0029] In the folded state, the arm 9 includes a lower surface 15 that faces downward between the tip 9a and the arm base end 9b. The arm base end 9b is the end opposite to the tip 9a and, in this embodiment, is the end that is attached to the interboom 8. The lower surface 15 of the arm 9 includes a main body flat surface 16 and a base end side inclined surface 17. The main body flat surface 16 extends horizontally and faces downward between the tip 9a and the arm base end 9b. The base end side inclined surface 17 is connected to the main body flat surface on the arm base end 9b side and is inclined upward toward the arm base end 9b side.

[0030] Figure 3 is a perspective view of the inclined surface 17 on the base end side, observed from below. As shown in Figure 3, the arm 9 includes a first grounding portion 11 and a second grounding portion 12. The first grounding portion 11 has a grounding surface 11s that is located on the lower surface 15 of the arm 9 and protrudes downward. In this embodiment, the first grounding portion 11 is located on the inclined surface 17 on the base end side. Furthermore, the grounding surface 11s of the first grounding portion 11 protrudes downward below the flat surface 16 of the main body. The first grounding portion 11 may, for example, be located on the flat surface 16 of the main body.

[0031] Furthermore, the second grounding portion 12 is positioned on the lower surface 15 so as to be located closer to the arm base end 9b than the first grounding portion 11, and protrudes downward. The grounding surface 12s of the second grounding portion 12 is located above the grounding surface 12s of the first grounding portion 11. In this embodiment, the second grounding portion 12 is positioned on the inclined surface 17 on the base end side, but is not limited to this configuration. The second grounding portion 12 only needs to be located closer to the arm base end 9b than the first grounding portion 11, and may be positioned on the flat surface 16 of the main body, for example.

[0032] In this invention, the inclusion of the first ground contact portion 11 and the second ground contact portion 12 in the arm 9 makes it easy to align the pin holes of these portions when connecting the front boom 7 and the main boom 5, and eliminates the need for a dedicated support structure for the arm's ground contact portion. The reason for this is as follows.

[0033] Figure 4(a) is an enlarged view of the first ground contact portion 11 when it is in contact with the ground. As shown in Figure 4(a) and Figure 2, in the present invention, when the folded work attachment 6 is placed on the ground G by itself (hereinafter, this state may be referred to as "attachment storage"), if the first ground contact portion 11 is in contact with the ground, at least a part of the lower surface of the arm 9 can be separated from the ground G. Furthermore, in a desirable embodiment, as shown in Figure 2, if the base end portion 7a of the front boom 7 is supported by the frame St, the entire lower surface 15 of the arm 9 can be separated from the ground G by the first ground contact portion 11 and the frame St. For this reason, in the work attachment 6 of the present invention, when the attachment is stored, there is no need to place cushioning material such as sleepers on the underside of the first ground contact portion 11 as in the conventional method.

[0034] Figure 4(b) is an enlarged view of the second ground contact portion 12 when it is in contact with the ground. As shown in Figure 4(b), since the second ground contact portion 12 is positioned in the above-described positional relationship with respect to the first ground contact portion 11, if the base end 7a side of the front boom 7 is lifted from the state in which the first ground contact portion 11 is in contact with the ground, the second ground contact portion 12 can be easily used as a pivot point to make contact with the ground, without having to place a dedicated support stand below the second ground contact portion 12. In other words, when assembling the attachment to connect the front boom 7 of the folded work attachment 6 to the main boom 5, when the base end 7a of the front boom 7 is lifted by making contact with the ground G using the second ground contact portion 12 as a pivot point, the first ground contact portion 11 can be lifted off the ground.

[0035] In this way, by using the second contact point 12 as a pivot and allowing the first contact point 11 to be lifted off the ground, the orientation of the work attachment 6 in the sideways direction can be easily changed by applying a small rotational moment to the work attachment 6. Therefore, the work attachment 6 of the present invention makes it easy to align the pin holes of the front boom 7 and the main boom 5 when connecting them, and eliminates the need for a dedicated stand for the contact point of the arm 9.

[0036] The configuration of this embodiment will be described in more detail below. Note that each configuration described below represents a specific aspect of this embodiment. Therefore, it goes without saying that the present invention can achieve the above-described effects even without the configurations described below. Furthermore, even if any one of the configurations described below is applied individually to the work machine 1 of the present invention having the above-described features, an improvement in performance corresponding to each configuration can be expected. Moreover, if several of the configurations described below are applied in combination, a combined improvement in performance corresponding to each configuration can be expected.

[0037] Figure 5 shows a schematic diagram of the first ground contact portion 11 and the second ground contact portion 12 as viewed from the front. As shown in Figures 4(a) and 5, the first ground contact portion 11 includes a plate-shaped member 18 that extends along the lower surface 15 of the arm 9 (shown in Figure 3), particularly along the main body flat surface 16. The first ground contact portion 11 is supported by a plurality of plate-shaped support members 20 that extend in a direction perpendicular to this plate-shaped member 18. As shown in Figure 5, in this embodiment, the plurality of plate-shaped support members 20 are directly connected, for example, to the base end side inclined surface 17. In another embodiment, a base plate may be interposed between the base end side inclined surface 17 and the plurality of plate-shaped support members 20, extending along the base end side inclined surface 17 and bolted to the base end side inclined surface 17 (not shown). Such an embodiment is desirable in that the plate-shaped support members 20 and the first ground contact portion 11 together with the base plate can be attached to and detached from the arm 9 as needed.

[0038] The plate-shaped support member 20 includes, for example, a central support member 21 provided in the center of the base end side inclined surface 17 in the width direction, and two outer support members 22 provided on both sides in the width direction so as to sandwich the central support member 21. The central support member 21 is provided, for example, in the central region when the base end side inclined surface 17 is divided into three equal parts in the width direction. The two outer support members 22 are positioned symmetrically with respect to the central support member 21. Furthermore, in order to reliably support the first ground contact portion 11, it is desirable that the two outer support members 22 be separated from each other to a certain extent. For this reason, the distance between the two outer support members 22 in the width direction is, for example, 50% or more of the total width of the base end side inclined surface 17.

[0039] Figure 6 shows a front view of the first ground contact portion 11 as observed from below. As shown in Figure 6, the first ground contact portion 11 is positioned to straddle the center position in the width direction of the arm 9, in order to provide sufficient stability when the attachment is stored. Furthermore, the width W1 of the ground contact surface 11s of the first ground contact portion 11 is greater than the width of the ground contact surface 12s of the second ground contact portion 12. Specifically, the width W1 of the ground contact surface 11s of the first ground contact portion 11 is 50% to 150% of the width of the arm 9. This prevents the work attachment 6 from swaying sideways when the attachment is stored. However, the width W1 of the ground contact surface 11s of the first ground contact portion 11 is not limited to this configuration, and various configurations can be adopted. In addition, in this embodiment, since the first ground contact portion 11 is supported by the central support member 21 and the two outer support members 22 described above, excessive bending of the plate-like member included in the first ground contact portion 11 can be suppressed.

[0040] In this embodiment, the first grounding portion 11, which has only one grounding surface 11s having the width described above, is provided on the arm 9, but the embodiment is not limited to this configuration. In other embodiments, the first grounding portion 11 may have multiple grounding surfaces. In this case, it is desirable that the multiple grounding surfaces 11s of the first grounding portion 11 be widely distributed on the lower surface 15 of the arm 9 so that sufficient stability can be achieved when the attachment is stored.

[0041] The first ground contact section 11 includes a main body section 25 that constitutes the maximum width, a width reduction section 26 whose width decreases towards the front from the main body section 25, and a fixed width section 27 that extends in front of the width reduction section 26 with a constant width. The main body section 25 is a horizontally elongated rectangle in the width direction of the base end side inclined surface 17 (shown in Figure 3). The width reduction section 26 has a lower base on the main body section 25 side and an upper base on the fixed width section 27 side, and has a roughly trapezoidal shape with the slanted side between them curved in a concave shape. In addition, the ground contact surface of the fixed width section 27 is formed by the side surface of a plate-shaped member that extends from the central support member 21. As a result, for example, when assembling the attachment, even if the base end 7a of the front boom 7 is slightly lifted and the width reduction section 26 and the fixed width section 27 are still in contact with the ground, it becomes easy to fine-tune the orientation of the work attachment 6 in the sideways tilting direction, further improving the workability when assembling the attachment.

[0042] As shown in Figures 3 and 4(a), the contact surface 11s of the first contact portion 11 extends along the lower surface 15, and more specifically, along the main body flat surface 16. This feature means that the maximum angle between the contact surface 11s of the first contact portion 11 and the main body flat surface 16 is, for example, 10° or less. In a more desirable configuration, the contact surface 11s of the first contact portion 11 and the main body flat surface 16 are substantially parallel (the maximum angle is, for example, 5° or less). This improves the stability when storing the attachment. However, the angle of the contact surface 11s of the first contact portion 11 is not limited to the above range. Furthermore, even if the contact surface 11s of the first contact portion 11 or the main body flat surface 16 includes uneven surfaces, the essential effects of the present invention will be achieved as long as the first contact portion 11 protrudes downward.

[0043] In this embodiment, it is desirable that the tip portion 9a (shown in Figure 2) of the first ground contact portion 11 has a series of inclined surfaces 30 that slope toward the lower surface 15 toward the tip portion 9a toward the tip portion 9a. This inclined surface 30 is inclined at an angle of 5 to 10° with respect to the ground when the first ground contact portion 11 is in contact with the ground. In the work machine 1 of this embodiment, when the base end portion 7a of the front boom 7 is lifted during attachment assembly, the first ground contact portion 11 moves toward the base machine 2 along the ground. At this time, the presence of the inclined surface 30 prevents the first ground contact portion 11 from digging into the ground.

[0044] The contact surface 12s of the second contact section 12 is connected to the contact surface 11s of the first contact section 11, and does not come into contact with the ground when the attachment is stored. On the other hand, when the base end 7a of the front boom 7 is lifted during attachment assembly, as shown in Figure 4(b), the contact surface of the second contact section 12 comes into contact with the ground, and as the position of the base end 7a moves upward, the second contact section 12 acts as a fulcrum to support the weight of the work attachment 6.

[0045] As shown in Figure 6, in this embodiment, the fixed-width portion 27 of the first grounding portion 11 and the second grounding portion 12 are made of a common plate-like member, and the side surface of this plate-like member is the grounding surface of the fixed-width portion 27 and the grounding surface 12s of the second grounding portion 12. Furthermore, this plate-like member is integrally connected to the plate-like support member 20 that constitutes the central support member 21 (shown in Figure 5). As a result, the width of the second grounding portion 12 is made sufficiently small, making it possible to easily adjust the orientation of the work attachment 6 in the sideways direction when assembling the attachment. The width W2 of the grounding surface of the second grounding portion 12 (shown in Figure 6), in other words, the thickness of the plate-like member that constitutes the second grounding portion 12 is appropriately set to a size that allows these members to exhibit sufficient durability.

[0046] As shown in Figure 5, the plate-like member constituting the second grounding portion 12 in this embodiment extends with a constant thickness. In another embodiment, the thickness of the plate-like member constituting the second grounding portion 12 may decrease toward the grounding surface 12s of the second grounding portion 12 (not shown). In this case, the width of the grounding surface 12s of the second grounding portion 12 can be made smaller. This makes it possible to expand the adjustable range of the orientation of the work attachment 6 in the lateral direction when assembling the attachment.

[0047] As shown in Figures 4(a) and 4(b), it is desirable that the contact surface 12s of the second contact portion 12 has a curved contour that is convex towards the front when viewed from the side of the arm 9. Such a second contact portion 12 increases the degree of freedom of the angle of the work attachment 6 with respect to the ground G (the angle when viewed from the side), and improves workability when assembling the attachment. Furthermore, such a second contact portion 12 can accommodate multiple specifications with different lengths of the front boom 7.

[0048] In another embodiment, the contact surface 12s of the second contact portion 12 may extend in a straight line when viewed from the side of the arm 9 (not shown). In this embodiment, the length of the contact surface 12s of the second contact portion 12 is greater than in the embodiment described above, so that damage to the ground when the second contact portion 12 is used as a pivot point can be suppressed.

[0049] Figure 7 is a perspective view showing the first ground portion 11 and the second ground portion 12 of another embodiment of the present invention. As shown in Figure 7, in this embodiment, the first ground portion 11 and the second ground portion 12 are provided separately on the arm 9. Specifically, the first ground portion 11 is supported by two outer support members 22, and a part of the second ground portion 12 is provided between the two outer support members 22. However, the plate-shaped member constituting the second ground portion 12 does not support the first ground portion 11. Note that in Figure 7, one of the two outer support members 22 is hidden by the first ground portion 11.

[0050] Compared to the embodiment shown in Figure 3, this embodiment is desirable because it offers greater design flexibility in both the first grounding portion 11 and the second grounding portion 12, and also reduces the constraints on their placement.

[0051] As a further improvement to the embodiment shown in Figure 7, it is desirable that the first grounding portion 11 and the second grounding portion 12 can be detached from the arm 9 by bolt fastening or the like (not shown). This makes it possible to accommodate various usage scenarios, such as removing the first grounding portion 11 and the second grounding portion 12 when operating the work machine 1 to reduce the weight of the work attachment 6.

[0052] The first ground contact points 11 may be provided in multiple locations along the longitudinal direction of the arm 9. In this case, the first ground contact points 11 are provided not only on the inclined surface 17 on the base end side, but also on the flat surface 16 of the main body of the arm 9. This further improves the stability when storing the attachment.

[0053] The second ground contact portion 12 is composed of a plate-like member extending downward from the inclined surface 17 on the base end side, and the side surface of this plate-like member becomes the ground contact surface 12s of the second ground contact portion 12. This ground contact surface 12s has a curved contour in a side view of the arm 9, and its radius of curvature can be made larger than that of the embodiment shown in Figure 3. Therefore, in this embodiment, it is possible to improve workability when connecting attachments and to prevent damage to the ground.

[0054] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the illustrated embodiments and can be implemented in various modified forms. [Industrial applicability]

[0055] As described above, the present invention is useful as a work machine and work attachment. [Explanation of Symbols]

[0056] 2 Base Machines 5 Main boom 6. Work Attachments 7 Front boom 9 Arms 11 1st grounding section 12 2nd grounding part

Claims

1. A work machine comprising a self-propelled base machine, a main boom mounted on the base machine in a manner that allows for raising and lowering, and a work attachment that can be detachably attached to the main boom, The aforementioned work attachment is, It includes a front boom having a base end connected to the main boom, and an arm positioned closer to the tip of the work attachment than the front boom, When the front boom is extended horizontally, the arm is extended horizontally below the front boom, allowing the front boom and the arm to face each other in a folded state. In the aforementioned folded state, The arm includes a longitudinal tip, an arm base end which is the end opposite to the tip, and a downward-facing lower surface between the tip and the arm base end. The aforementioned arm is A first grounding portion is provided on the lower surface and has a grounding surface that protrudes downward, It includes a second grounding portion which is positioned on the lower surface so as to be closer to the base end of the arm than the first grounding portion, protruding downward, and having a grounding surface that is located above the grounding surface of the first grounding portion, A type of machinery used for industrial work.

2. The work machine according to claim 1, in the process of assembling the attachment to connect the front boom of the folded work attachment to the main boom, when the base end of the front boom is lifted by making contact with the ground using the second ground contact point as a fulcrum, the first ground contact point is lifted off the ground.

3. The working machine according to claim 2, wherein the contact surface of the first contact portion extends along the lower surface.

4. The work machine according to claim 3, wherein the contact surface of the first contact portion has a series of inclined surfaces on the tip side that are inclined toward the lower surface toward the tip side.

5. The working machine according to any one of claims 1 to 4, wherein the contact surface of the second contact portion has a curved contour in a side view of the arm.

6. The first grounding portion is composed of a plate-shaped member extending along the lower surface and is supported by a plurality of plate-shaped support members extending in a direction perpendicular to the plate-shaped member. A work machine according to any one of claims 1 to 4, wherein a part of the plate-shaped support member constitutes the second ground contact portion.

7. The working machine according to claim 6, wherein the width of the contact surface of the first contact portion is greater than the width of the contact surface of the second contact portion.

8. A work attachment that can be detachably attached to the main boom of a work machine, It includes a front boom having a base end connected to the main boom, and an arm positioned closer to the tip of the work attachment than the front boom, When the front boom is extended horizontally, the arm is extended horizontally below the front boom, allowing the front boom and the arm to face each other in a folded state. In the aforementioned folded state, The arm includes a longitudinal tip, an arm base end which is the end opposite to the tip, and a downward-facing lower surface between the tip and the arm base end. The aforementioned arm is A first grounding portion is provided on the lower surface and has a grounding surface that protrudes downward, It includes a second grounding portion which is positioned on the lower surface so as to be closer to the base end of the arm than the first grounding portion, protruding downward, and having a grounding surface that is located above the grounding surface of the first grounding portion, Work attachment.

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