crane

Abstract

To provide a crane capable of maintaining the stability of a machine body with respect to the change of a lifting condition including the length of a derricking body and the weight of a suspended load without increasing / decreasing the weight of a counterweight mounted on the machine body.SOLUTION: A crane 10 includes a base weight 13A, a counterweight 13B, and a link unit 70. A weight front connection part 13P of the base weight 13A is selectively connected to a frame front connection part 122P and a frame rear connection part 122Q of a revolving frame 120. A weight rear connection part 13Q of the base weight 13A is connected to a sheave mounting part 122S of the revolving frame 120 with a link unit 70 while the weight front connection part 13P is connected to the frame rear connection part 122Q.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a crane having a counterweight. [Background technology]

[0002] Conventionally, a mobile crane is known that includes a machine body including a lower traveling body and an upper rotating body, and a boom or other lifting body. Such a crane is capable of lifting a load by a hook suspended from the tip of the boom. Patent Document 1 discloses a crane having a counterweight. The counterweight is loaded on the rear end of the rotating frame of the upper rotating body. The counterweight has a function of maintaining the balance of the crane between the weight of the boom and the weight of the load, and is also a factor that determines the maximum lifting capacity of the crane. When the weight of the load increases, the front moment acting on the machine body to tilt the crane forward increases. Therefore, in order to stably lift such a load, it is necessary to increase the number of counterweights and increase the rear moment acting on the machine body to tilt the crane backward, thereby balancing the rear moment and the front moment and maintaining the stability of the crane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-226530 A Summary of the Invention [Problem to be solved by the invention]

[0004] With the technology described in Patent Document 1, when increasing the maximum lifting capacity of the crane or extending the boom length in accordance with the weight of the load at the work site, it is necessary to add a pallet weight to the rear part of the rotating frame or to attach a counterweight cart to the rear of the rotating frame, which poses the problem of the need to prepare for this and secure space for transportation and storage.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a crane that can maintain the stability of the machine body in response to changes in lifting conditions, including the length of the hoisting body and the weight of the suspended load, without increasing or decreasing the weight of the counterweight attached to the machine body. [Means for solving the problem]

[0006] A crane according to one aspect of the present invention comprises a machine body, a hoisting body having a base end portion supported on the machine body so as to be rotatable in a hoisting direction, a counterweight, a base weight which has a mounting surface to allow the counterweight to be placed on it and is removably attached to the machine body at least at a front position and a rear position which is rearward of the front position and positioned so as to protrude rearward from the machine body further than the front position, and an auxiliary connecting member capable of connecting the machine body to the portion of the base weight which protrudes rearward from the machine body at the rear position.

[0007] According to this configuration, the base weight can be positioned at multiple positions in front and behind the machine body by changing the connection point of the base weight to the machine body at least between the front position and the rear position. Therefore, it is possible to change the magnitude of the moment applied to the machine body by the counterweight and the base weight without changing the weight of the counterweight mounted on the base weight in response to changes in lifting conditions including the length of the hoisting body and the weight of the suspended load, and it is possible to maintain the stability of the machine body. In addition, since the auxiliary connecting member can connect the part of the base weight located rearward of the machine body to the machine body, it is possible to prevent the rear part of the base weight from bending downward.

[0008] In the above configuration, the airframe has a frame, a plurality of pairs of frame connectors arranged on the frame behind the hoisting body, the plurality of pairs of frame connectors including a pair of left and right frame front connectors and a pair of left and right frame rear connectors arranged behind the pair of left and right frame front connectors, and a frame auxiliary connector arranged at a rear end of the frame, and the base weight has a pair of left and right weight front connectors that can be selectively connected to the pair of left and right frame front connectors and the pair of left and right frame rear connectors, and the pair of left and right weight front connectors are connected to the pair of left and right frame front connectors. a pair of left and right weight rear connecting parts arranged rear of the pair of left and right weight front connecting parts so as to be connectable to the pair of left and right frame rear connecting parts in a front connecting state in which the pair of left and right weight front connecting parts are connected to the pair of left and right frame rear connecting parts, and a pair of left and right weight rear connecting parts arranged rear of the frame in a rear connecting state in which the pair of left and right weight front connecting parts are connected to the pair of left and right frame rear connecting parts, and it is desirable that the auxiliary connecting member is capable of connecting the frame auxiliary connecting parts and the pair of left and right weight rear connecting parts to each other in the rear connecting state.

[0009] According to this configuration, by changing the connection points of the base weight to the pairs of frame connection parts arranged on the frame, it is possible to stably arrange the base weight in multiple positions in the front and rear. Therefore, it is possible to stably change the magnitude of the moment applied to the machine body by the counterweight and the base weight without changing the weight of the counterweight mounted on the base weight in response to changes in the lifting conditions including the length of the hoisting body and the weight of the suspended load, and it is possible to maintain the stability of the machine body. In addition, since the auxiliary connecting member can connect the pair of left and right weight rear connecting parts located rearward of the frame to the frame auxiliary connecting part, it is possible to stably prevent the rear part of the base weight from bending downward.

[0010] In the above configuration, the hoisting body further has a hoisting body tip portion arranged on the opposite side to the hoisting body base end portion, and further includes a hoisting device supported by the frame at the rear of the hoisting body and connected to the hoisting body tip portion and capable of rotating the hoisting body in the hoisting direction, and the hoisting device has a frame connection portion connected to the rear end of the frame so that at least an upward force is applied to the rear end of the frame when the hoisting device supports the hoisting body in a state where the hoisting body extends forward and upward from the body, and it is desirable that the frame auxiliary connection portion is arranged alongside the frame connection portion at the rear end of the frame so that at least a downward force is applied to the frame connection portion due to the weight of the counterweight when the auxiliary connection member connects the frame auxiliary connection portion and the pair of left and right weight rear connection portions to each other.

[0011] With this configuration, the weight of the counterweight is applied downward to the frame connection part through the auxiliary connecting member, while the weight of the elevation body and the suspended load acts on the frame connection part so that the tip of the elevation body pulls the frame connection part upward. As a result, the frame connection part connected to the tip of the elevation body functions to support the pair of left and right weight rear connecting parts via the auxiliary connecting member, preventing the part of the base weight located rearward of the frame from bending downward and increasing the stability of the aircraft.

[0012] In the above configuration, the auxiliary frame connection portion has a plurality of pin support portions arranged at intervals in the left-right direction at the rear end of the frame, and a support pin extending in the left-right direction so as to connect the plurality of pin support portions to each other, and the hoisting device includes a mast having a mast base end supported on the frame to be rotatable in the hoisting direction and a mast tip end opposite to the mast base end, rear of the hoisting body and forward of the auxiliary frame connection portion, a guy line connecting the mast tip end and the hoisting body tip end to each other, a mast side sheave block including a first sheave and supported by the mast tip end, and a support pin extending in the left-right direction so as to connect the frame to the hoisting body and the support pin. a frame side sheave block supported by the support pin of the mast auxiliary connection part and constituting the frame connection part, a hoisting rope stretched between the first sheave of the mast side sheave block and the second sheave of the frame side sheave block, and a hoisting winch capable of changing the distance between the mast side sheave block and the frame side sheave block by winding and letting out the hoisting rope, thereby raising and lowering the hoisting body together with the mast, and it is desirable that the auxiliary connecting member connects the support pin of the frame auxiliary connection part and the pair of left and right weight rear connecting parts to each other.

[0013] According to this configuration, when the counterweight is placed on the base weight, the weight of the base weight and the counterweight is applied at least downward to the support pin through the base weight, the pair of left and right weight rear connectors, and the auxiliary connector. On the other hand, when the hoisting device supports the hoisting body, at least an upward force is applied to the support pin through the tip of the hoisting body, the guy line, the mast side sheave block, the hoisting rope, and the frame side sheave block. Therefore, the frame side sheave block connected to the tip of the hoisting body functions to directly support the pair of left and right weight rear connectors via the support pin, which further prevents the portion of the base weight located rearward of the frame from bending downward, thereby further improving the stability of the aircraft.

[0014] In the above configuration, it is desirable that the base weight has a dimension such that it protrudes on both left and right sides beyond the frame when viewed from the front-rear direction, the support surface includes a right support surface and a left support surface arranged on both the left and right sides of the frame when viewed from the front-rear direction, and the auxiliary connecting member includes a pair of left and right first connecting members respectively connected to the support pins on both the left and right sides of the frame side sheave block, and a second connecting member including a pair of left and right upper connecting portions respectively connected to the pair of left and right first connecting members, and a pair of left and right lower connecting portions respectively connected to the pair of left and right weight rear connecting portions outside the pair of left and right first connecting members.

[0015] According to this configuration, it is possible to place the counterweight on the right and left mounting surfaces of the base weight, which are arranged on both the left and right sides of the frame when viewed from the fore-aft direction, thereby increasing the stability of the aircraft not only in the fore-aft direction but also in the left-right direction.In addition, by arranging a pair of first connecting members on both the left and right sides of the frame side sheave block in the left-right direction, it is easier to transmit force between the frame side sheave block and the auxiliary connecting member via the support pin, while the base weight, which is wider in the left-right direction than the frame, can be stably supported by the pair of left and right lower connecting parts of the auxiliary connecting member.

[0016] In the above configuration, the frame auxiliary connecting portion may be fixed to the frame so as to be aligned with the frame connecting portion in the left-right direction at the rear end of the frame. Also, the frame auxiliary connecting portion may be aligned with the frame connecting portion in the front-rear direction at the rear end of the frame. Effect of the Invention

[0017] According to the present invention, a crane is provided that can maintain the stability of the machine body in response to changes in lifting conditions, including the length of the hoisting body and the weight of the suspended load, without increasing or decreasing the weight of the counterweight attached to the machine body. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a side view of a crane according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of a lower frame and a rotating frame of a crane according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view of a rotating frame of the crane according to one embodiment of the present invention. [Figure 4] FIG. 1 is a schematic side view showing a state in which the counterweight according to an embodiment of the present invention is disposed at a front position. [Diagram 5] FIG. 5 is a schematic side view of the counterweight of FIG. 4 with a portion thereof omitted. [Figure 6] FIG. 1 is a schematic side view showing a state in which the counterweight according to an embodiment of the present invention is disposed at a rear position. [Figure 7] FIG. 7 is a schematic side view of the counterweight of FIG. 6 with a portion thereof omitted. [Figure 8] FIG. 2 is a rear view of a rotating frame and a weight unit of the crane according to one embodiment of the present invention. [Figure 9] FIG. 2 is a horizontal cross-sectional view of a frame side sheave block of the crane according to one embodiment of the present invention. [Figure 10]FIG. 2 is a side view of a state in which a frame side sheave block is supported on a revolving frame of the crane according to one embodiment of the present invention. [Figure 11] FIG. 2 is a plan view of a slewing frame and a sheave-side link of a crane according to a first modified embodiment of the present invention. [Figure 12] FIG. 2 is a side view of a slewing frame and a sheave-side link of a crane according to a first modified embodiment of the present invention. [Figure 13] FIG. 11 is a plan view of a revolving frame and a sheave-side link of a crane according to a second modified embodiment of the present invention. [Figure 14] FIG. 11 is a side view of a revolving frame and a sheave-side link of a crane according to a second modified embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a side view of a crane 10 (work machine) according to an embodiment of the present invention. In the following drawings, directions such as "up", "down", "front" and "rear" are shown for the sake of convenience in explaining the structure and assembly method of the crane 10 according to the present invention, and do not limit the movement direction or usage mode of the crane 10.

[0020] The crane 10 comprises an upper rotating body 12 which corresponds to the crane main body (machine body), a weight unit 13, a lower running body 14 which supports the upper rotating body 12 so that it can rotate, a hoisting member (hoisting body) including a boom 16 and a jib 18, and a mast 20 which is a boom hoisting member. A weight unit 13 (base weight 13A, counterweight 13B, FIG. 4) for adjusting the balance of the crane 10 is loaded on the rear of the upper rotating body 12. In addition, a cab 15 is provided on the front end of the upper rotating body 12. The cab 15 corresponds to the driver's seat of the crane 10.

[0021] The boom 16 shown in Fig. 1 is a so-called lattice type, and is composed of a base end member 16A, one or more (two in the illustrated example) intermediate members 16B, 16C, and a tip end member 16D. A rear strut 21 and a front strut 22 for rotating the jib 18, as described below, are rotatably connected to the tip of the tip end member 16D. The boom 16 is rotatably supported on the upper rotating structure 12 with a boom foot pin 16S provided at the lower end as a fulcrum. In other words, the boom 16 has a boom base end (hoisting structure base end) that is rotatably supported in the hoisting direction on the upper rotating structure 12, and a boom tip end (hoisting structure tip end) on the opposite side to the boom base end.

[0022] However, the present invention is not limited to a specific boom structure. For example, the boom may not have an intermediate member, or may have a different number of intermediate members from the above. Furthermore, the boom may be composed of a single member.

[0023] The jib 18 is also not limited to a specific structure, but has a lattice structure in the illustrated example. The base end of the jib 18 is rotatably connected (pivotally supported) to the tip of the tip side member 16D of the boom 16, and the rotation center axis of the jib 18 is a horizontal axis parallel to the rotation center axis of the boom 16 relative to the upper rotating body 12 (boom foot pin 16S).

[0024] The mast 20 has a mast base end and a mast tip end. The mast base end is supported by the revolving frame 120 at the rear of the boom 16 and in front of a sheave mounting portion 122S (FIG. 2) described later so as to be rotatable in the hoisting direction. The rotation axis of the mast 20 is parallel to the rotation axis of the boom 16 and is located immediately rearward of the rotation axis of the boom 16. In other words, the mast 20 is rotatable in the same direction as the hoisting direction of the boom 16. On the other hand, the mast tip end of the mast 20 is located on the opposite side to the mast base end and is connected to the boom tip end of the boom 16 via a pair of left and right boom guy lines 24. In other words, the pair of left and right boom guy lines 24 connect the mast tip end and the boom tip end to each other. This connection coordinates the rotation of the mast 20 and the rotation of the boom 16.

[0025] Furthermore, the crane 10 has a rear strut 21, a front strut 22, a pair of left and right backstops 23, a pair of left and right boom guylines 24, and a pair of left and right backstops 25.

[0026] A pair of left and right backstops 23 are provided on the base end member 16A of the boom 16. These backstops 23 abut against both left and right sides of the upper rotating body 12 when the boom 16 reaches the upright position shown in Fig. 1. This abutment prevents the boom 16 from being blown backward by strong winds, etc.

[0027] The rear strut 21 and the front strut 22 are pivotally supported at the tip of the boom 16. The rear strut 21 is held in a position in which it projects from the tip of the tip-side member 16D toward the boom rising side (rear side in FIG. 1). As a means for holding this position, a pair of left and right backstops 25 and a pair of left and right guy links 26 are interposed between the rear strut 21 and the boom 16. The backstops 25 are interposed between the tip-side member 16D and an intermediate portion of the rear strut 21, and support the rear strut 21 from below. The guy links 26 are tensioned to connect the tip of the rear strut 21 and the base-end member 16A of the boom 16, and the position of the rear strut 21 is restricted by the tension of the guy links. In another embodiment, the rear strut 21 and the front strut 22 may be pivotally supported at the base end of the jib 18. In addition, the rear strut 21 may be rotatably supported at the tip of the boom 16, and the front strut 22 may be rotatably supported at the base end of the jib 18.

[0028] The front strut 22 is connected to the jib 18 so as to rotate in conjunction with (integrally with) the jib 18. More specifically, a pair of left and right jib guy lines 28 are tensioned to connect the tip of the front strut 22 with the tip of the jib 18. Therefore, the jib 18 is also driven to rotate by driving the front strut 22 to rotate. The above-mentioned rear strut 21 is disposed rearward of the front strut 22 as shown in FIG. 1, and forms a substantially isosceles triangle shape with the front strut 22.

[0029] The crane 10 is equipped with various winches. Specifically, a boom hoist winch 30 for raising and lowering the boom 16, a jib hoist winch 32 for rotating the jib 18 in the hoisting direction, and a main winch 34 and an auxiliary winch 36 for hoisting and lowering a load are installed. In the crane 10 according to this embodiment, the boom hoist winch 30 is installed on the upper rotating body 12. Also, the jib hoist winch 32, the main winch 34, and the auxiliary winch 36 are all installed on the base end member 16A of the boom 16. These winches 32, 34, and 36 may be mounted on the upper rotating body 12.

[0030] The boom hoist winch 30 winds and pays out the boom hoist rope 38. The boom hoist rope 38 is arranged so that the mast 20 rotates as a result of this winding and paying out. Specifically, a sheave block 40 (mast side sheave block) and a sheave block 42 (frame side sheave block) in which multiple sheaves (first sheave, second sheave) are arranged in the width direction are provided at the mast tip of the mast 20 and the rear end of the upper rotating body 12, respectively, and the boom hoist rope 38 (hoist rope) drawn out from the boom hoist winch 30 is hung between the sheaves of the sheave blocks 40, 42. Therefore, when the boom hoist winch 30 (hoist winch) winds and pays out the boom hoist rope 38, the distance between the two sheave blocks 40, 42 changes, and as a result, the mast 20 and the boom 16 linked thereto are raised and lowered.

[0031] The jib hoist winch 32 winds and pays out the jib hoist rope 44 wound between the rear strut 21 and the front strut 22. The jib hoist rope 44 is arranged so that the front strut 22 rotates as a result of this winding and paying out. Specifically, a guide sheave 46 is provided in the middle of the longitudinal direction of the rear strut 21, and sheave blocks 47, 48, in which a plurality of sheaves are arranged in the width direction, are provided at the rotating end of the rear strut 21 and the rotating end of the front strut 22, respectively. The jib hoist rope 44 drawn out from the jib hoist winch 32 is hung around the guide sheave 46 and stretched between the sheave blocks 47, 48. Therefore, winding or unwinding the jib hoist rope 44 by the jib hoist winch 32 changes the distance between the two sheave blocks 47, 48, rotating the front strut 22 and, further, the jib 18 connected thereto in the hoisting direction.

[0032] The main winch 34 hoists and lowers a load using a main hoisting rope 50 (winding rope). For this main hoisting, main hoisting guide sheaves 52, 53, 54 are rotatably provided at the base end vicinity of the rear strut 21, the base end vicinity of the front strut 22, and the tip of the jib 18, respectively, and further, a main hoisting sheave block is provided adjacent to the main hoisting guide sheave 54, in which multiple main hoisting point sheaves 56 are arranged in the width direction. The main hoisting rope 50 drawn out from the main hoisting winch 34 is hung in order around the main hoisting guide sheaves 52, 53, 54, and is stretched between the main hoisting point sheave 56 of the sheave block and a sheave 58 of a sheave block provided on a main hook 57 (hook) for hoisting a load. Therefore, when the main winding winch 34 (winding winch) winds or unwinds the main winding rope 50, the distance between the two sheaves 56, 58 changes, and the main hook 57 connected to the main winding rope 50 hanging down from the tip of the jib 18 is wound up and down.

[0033] Similarly, the auxiliary winch 36 hoists and lowers a load using the auxiliary hoisting rope 60. For this auxiliary hoisting, auxiliary guide sheaves 62, 63, and 64 are rotatably mounted coaxially with the main hoisting guide sheaves 52, 53, and 54, respectively, and an auxiliary point sheave (not shown) is rotatably mounted adjacent to the auxiliary guide sheave 64. The auxiliary hoisting rope 60 pulled out from the auxiliary hoisting winch 36 is hung in turn around the auxiliary guide sheaves 62, 63, and 64, and suspended from the auxiliary point sheave. Therefore, when the auxiliary hoisting winch 36 winds or unwinds the auxiliary hoisting rope 60, an auxiliary hook for a suspended load (not shown) connected to the end of the auxiliary hoisting rope 60 is wound up or lowered.

[0034] The crane 10 also has a hoisting device 16T (Fig. 1). The hoisting device 16T includes the above-mentioned mast 20, boom guy line 24, sheave block 40, sheave block 42, boom hoist rope 38, and boom hoist winch 30. The hoisting device 16T is supported by a revolving frame 120 (Fig. 2) of the upper rotating body 12 at the rear of the boom 16 and is connected to the boom tip of the boom 16, enabling the boom 16 to rotate in the hoisting direction.

[0035] Fig. 2 is a side view of the lower frame 140 and the revolving frame 120 of the crane 10 according to this embodiment. Fig. 3 is a plan view of the revolving frame 120 of the crane 10 according to this embodiment. In the following description, the up-down, left-right, and front-rear directions are indicated based on the upper revolving body 12 (revolving frame 120). The crane 10 further has a revolving bearing 10S.

[0036] The lower traveling body 14 has a lower frame 140. The lower frame 140 is a frame body that supports each member of the lower traveling body 14, and supports a later-described revolving frame 120 of the upper rotating body 12 so as to be revolvable around a revolving center axis CL extending in the vertical direction. More specifically, the lower frame 140 includes a car body (not shown) that revolvably supports the upper rotating body 12, and a pair of left and right crawler bodies that are respectively attached to the left and right side surfaces of the car body. The crawler body supports a crawler so as to be able to rotate. FIG. 3 illustrates a front crawler shaft 140A that is a rotating shaft of a front roller that supports the crawler so as to be able to rotate on the front side of the crawler body, and a rear crawler shaft 140B that is a rotating shaft of a rear roller that supports the crawler so as to be able to rotate on the rear side of the crawler body.

[0037] The upper rotating body 12 has a revolving frame 120 (frame). The revolving frame 120 is a frame main body that supports each member of the upper rotating body 12. The revolving frame 120 is supported on the lower frame 140 of the lower running body 14 via a revolving bearing 10S so as to be revolvable about a revolving central axis CL extending in the vertical direction. In other words, the revolving bearing 10S connects the revolving frame 120 and the car body of the lower frame 140 so that the revolving frame 120 can revolve about the revolving central axis CL.

[0038] The rotating frame 120 has a pair of left and right side plates 121A (Figure 3), a rear cross plate 121B, a pair of left and right boom foot support portions 121S, a pair of left and right mast foot support portions 121T, a pair of left and right front frame connecting portions 122P (Figure 2), a pair of left and right rear frame connecting portions 122Q, and a pair of left and right sheave mounting portions 122S.

[0039] Each of the pair of left and right side plates 121A has a predetermined height in the up-down direction and extends long in the front-rear direction. A pair of left and right boom foot shaft supports 121S are provided at the front ends of the pair of left and right side plates 121A, and a pair of left and right mast foot shaft supports 121T are provided immediately behind the boom foot shaft supports 121S. The boom foot shaft supports the boom foot of the boom 16 so that it can be raised and lowered. The mast foot shaft supports the mast foot of the mast 20 so that it can be raised and lowered.

[0040] The pair of left and right frame front connectors 122P and the pair of left and right frame rear connectors 122Q constitute a plurality of pairs of frame connectors of the present invention. The plurality of pairs of frame connectors are respectively disposed on the revolving frame 120 behind the boom 16. The pair of left and right frame front connectors 122P are respectively disposed on the lower surfaces of the pair of left and right side plates 121A, and as shown in FIG. 2, are disposed approximately in the center between the revolving bearing 10S and the rear end of the revolving frame 120 in the front-rear direction. On the other hand, the pair of left and right frame rear connectors 122Q are disposed on the lower surfaces and rear end of the pair of left and right side plates 121A. That is, the pair of left and right frame rear connectors 122Q are disposed behind the pair of left and right frame front connectors 122P. Each of these frame connectors has a pin hole that can receive a connector pin P2 (see FIG. 8) along the left-right direction.

[0041] The rear horizontal plate 121B connects the rear ends of the pair of left and right side plates 121A in the left-right direction. A pair of left and right sheave mounting parts 122S (frame auxiliary connecting parts) are arranged at a distance from each other in the center of the rear horizontal plate 121B that constitutes the rear end of the revolving frame 120. The sheave mounting parts 122S have a function of rotatably supporting the above-mentioned sheave block 42. As shown in FIG. 3, the pair of left and right side plates 121A are connected to each other not only by the rear horizontal plate 121B but also by a plurality of horizontal plates in front of the rear horizontal plate 121B.

[0042] FIG. 4 is a schematic side view of the weight unit 13 according to this embodiment in a state where it is arranged at the front position (front-side connected state). FIG. 5 is a schematic side view of the weight unit 13 in FIG. 4 with a part of the weight unit 13 omitted. FIG. 6 is a schematic side view of the weight unit 13 according to this embodiment in a state where it is arranged at the rear position (rear-side connected state). FIG. 7 is a schematic side view of the weight unit 13 in FIG. 6 with a part of the weight unit 13 omitted. FIG. 8 is a rear view of the revolving frame 120 and the counterweight 13B of the crane 10 according to this embodiment. FIG. 9 is a horizontal cross-sectional view of the sheave block 42 of the crane 10 according to this embodiment. FIG. 10 is a side view of the sheave block 42 supported by the revolving frame 120 of the crane 10 according to this embodiment.

[0043] The weight unit 13 includes a base weight 13A and a plurality of counterweights 13B mounted (placed) on the base weight 13 A. Furthermore, the crane 10 has a link unit 70 (auxiliary connecting member) (FIG. 7).

[0044] The base weight 13A has a mounting surface 13H on which the counterweights 13B are placed, and is detachably attached to the rear end of the revolving frame 120. In this embodiment, the base weight 13A is detachably attached to the upper revolving body 12 at least at a front position and a rear position that is a position rearward of the front position and protrudes rearward from the upper revolving body 12 more than the front position. The base weight 13A is a plate-shaped weight member that has a substantially rectangular shape in a plan view and a predetermined thickness in the vertical direction. As shown in FIG. 8, the base weight 13A has a left-right dimension that protrudes on both sides of the revolving frame 120 in the left-right direction when viewed from the front-rear direction. The mounting surface 13H of the base weight 13A includes a right mounting surface 13HR and a left mounting surface 13HL that are respectively disposed on both the left and right sides of the revolving frame 120 when viewed from the front-rear direction. As shown in Fig. 8, the multiple counterweights 13B are weights that are stacked on the right and left support surfaces 13HR and 13HL, respectively. For safety, the counterweights 13B are fixed to each other and to the lowest counterweight 13B and base weight 13A by a fixing device (not shown). The base weight 13A does not need to have a clear function as a weight, as long as it is a member on which the counterweight 13B can be placed and has a predetermined weight.

[0045] Furthermore, the base weight 13A has a pair of left and right weight front connecting parts 13P and a pair of left and right weight rear connecting parts 13Q. The interval between the pair of left and right weight front connecting parts 13P and the interval between the pair of left and right weight rear connecting parts 13Q are set to correspond to the interval between the pair of left and right frame front connecting parts 122P and the interval between the pair of left and right frame rear connecting parts 122Q. Also, each connecting part has a pin hole through which the connecting pin P2 can be inserted. In this embodiment, the pair of left and right weight front connecting parts 13P and the pair of left and right weight rear connecting parts 13Q are disposed on the upper surface of the base weight 13A (FIGS. 7 and 8).

[0046] The pair of left and right weight front connecting portions 13P can be selectively connected to the pair of left and right frame front connecting portions 122P and the pair of left and right frame rear connecting portions 122Q by a pair of left and right connecting pins P2 (FIGS. 5 and 7).

[0047] The pair of left and right rear weight connectors 13Q are disposed behind the pair of left and right front weight connectors 13P. The relative positions of the pair of left and right rear weight connectors 13Q to the pair of left and right front weight connectors 13P in the front-rear direction are set so that the pair of left and right rear weight connectors 13Q can be connected to the pair of left and right rear frame connectors 122Q in a front connection state in which the pair of left and right front weight connectors 13P are connected to the pair of left and right front frame connectors 122P, that is, so that the connection pin P2 can be inserted into the pin hole formed in each connector. Furthermore, in a rear connection state in which the pair of left and right front weight connectors 13P are connected to the pair of left and right rear frame connectors 122Q, the pair of left and right rear weight connectors 13Q are disposed behind the revolving frame 120 (see FIG. 7).

[0048] As described above, the pair of left and right sheave mounting portions 122S (auxiliary frame connectors) are disposed at the rear end of the revolving frame 120. Specifically, as shown in Fig. 8, the sheave mounting portion 122S has a plurality of sheave support portions 122B (a plurality of pin support portions) and a sheave support pin 122A (support pin). The plurality of sheave support portions 122B are plate-like members disposed at intervals in the left-right direction at the rear end of the revolving frame 120. The sheave support pin 122A extends in the left-right direction so as to connect the plurality of sheave support portions 122B to each other.

[0049] The structure of the sheave block 42 (frame connection portion) in FIG. 1 will be described in more detail with reference to FIG. 9 and FIG. 10. The sheave block 42 is a unit (also called a spreader) that rotatably supports the sheaves 420 so that the sheaves 420 can be attached to the sheave attachment portion 122S. The sheave block 42 has a sheave holder 42H that rotatably supports the sheaves 420, and a sheave shaft 42T that forms the rotation shaft of the sheaves 420. Among the multiple sheave support portions 122B shown in FIG. 8, two sheave support portions 122B in the center are fitted into two fitting portions on the left and right sides formed in the sheave holder 42H, as shown in FIG. 9. The fitting portions are provided with anti-detachment members that prevent the sheave support pins 122A from coming off. In another embodiment, the sheave support pin 122A may be separated on the left and right sides, and a pin hole through which the sheave support pin 122A can be inserted may be formed in the fitting portion of the sheave holder 42H. In this case, the two sheave support portions 122B are fitted into the two fitting portions formed on the left and right sides of the sheave holder 42H, and then the sheave support pin 122A is inserted into each pin hole, so that the sheave block 42 is rotatably supported by the sheave mounting portion 122S. FIG. 10 shows a state in which the sheave block 42 is attached to and supported by the sheave mounting portion 122S. When the boom hoisting rope 38 is stretched between the sheave block 40 and the sheave block 42 and tension is applied, the sheave block 42 rotates upward from the state shown in FIG. 10 around the sheave support pin 122A.

[0050] As described above, the sheave block 42 is attached (connected) to the sheave mounting portion 122S in Fig. 8. More specifically, the sheave block 42 is supported by the sheave support pin 122A of the sheave mounting portion 122S. The sheave block 42 also constitutes the above-mentioned hoisting device 16T. The sheave block 42 is supported by the sheave mounting portion 122S of the revolving frame 120 so that when the hoisting device 16T supports the boom 16 so as to be capable of hoisting as shown in Fig. 1, at least an upward force is applied to the rear end portion of the revolving frame 120 as shown by the arrow DS in Fig. 7.

[0051] The link unit 70 is capable of connecting the upper rotating body 12 to a portion of the base weight 13A disposed at the rear position that protrudes rearward from the upper rotating body 12. In particular, in this embodiment, the link unit 70 is capable of connecting the revolving frame 120 of the upper rotating body 12 to the base weight 13A. Specifically, the link unit 70 is capable of connecting the sheave support pin 122A of the sheave mounting portion 122S to the pair of left and right weight rear connecting portions 13Q to each other in the rear connected state (FIG. 7).

[0052] The link unit 70 has a pair of left and right sheave side links 71 (first connecting members) and a weight side link 72 (second connecting member).

[0053] As shown in Fig. 8, the pair of left and right sheave side links 71 are respectively connected to the sheave support pins 122A on both the left and right sides of the sheave block 42 (sheave mounting portion 122S). The pair of left and right sheave side links 71 may be connected to the sheave support pins 122A in advance, or may be connected to the sheave support pins 122A as necessary. In this embodiment, each sheave side link 71 is made of a pair of plate-like members, and a pin hole (not shown) is formed in the lower end thereof, through which the connecting pin P1 can be inserted.

[0054] The weight-side link 72 connects the pair of left and right sheave-side links 71 to the pair of left and right weight rear connecting portions 13Q of the base weight 13A. The weight-side link 72 has a link base portion 721, a pair of left and right upper links 722 (upper connecting portions), and a pair of left and right lower links 723 (lower connecting portions).

[0055] The link base portion 721 constitutes the main body of the upper link 722, and is a plate-like member or a rectangular parallelepiped member extending in the left-right direction, and is inclined upward toward the front. Note that the shape and structure of the link base portion 721 are not limited to this embodiment.

[0056] The pair of left and right upper links 722 are arranged at a distance from each other in the center of the link base portion 721 in the left-right direction. The pair of left and right upper links 722 are arranged to extend upward from the link base portion 721, and at their upper ends, a pin hole (not shown) through which the connecting pin P1 can be inserted is formed. The pair of left and right upper links 722 are connected to the pair of left and right sheave side links 71 by the connecting pin P1. The pair of left and right lower links 723 are arranged at both ends of the link base portion 721 in the left-right direction, that is, on the outside in the left-right direction of the pair of left and right sheave side links 71. The pair of left and right lower links 723 are arranged to extend downward from the link base portion 721, and at their lower ends, a pin hole (not shown) through which the connecting pin P2 can be inserted is formed. The pair of left and right lower links 723 are connected to the pair of left and right weight rear connecting portions 13Q described above by the connecting pin P2 (FIG. 8).

[0057] Next, a process of moving the weight unit 13 including the base weight 13A and the counterweight 13B in the front-rear direction in the crane 10 according to this embodiment will be described. In the following description, the pair of left and right sheave side links 71 (FIG. 8) are connected in advance to the sheave mounting portion 122S (sheave support pin 122A) (FIG. 5).

[0058] 4 and 5, when the weight unit 13 is in the front connection state (placed in the front position), the worker first detaches the multiple counterweights 13B from the base weight 13A. At this time, the multiple counterweights 13B mounted on the placement surface 13H may be detached one by one, or the multiple counterweights 13B may be detached all at once.

[0059] Next, the worker uses an auxiliary crane (not shown) to hoist the multiple counterweights 13B, removes them from the base weight 13A, and lowers them to the ground.

[0060] Next, while suspending the base weight 13A with an auxiliary crane, the worker removes the connections to the revolving frame 120. Specifically, the worker removes the pair of left and right connecting pins P2 connecting the pair of left and right frame front connecting parts 122P to the pair of left and right weight front connecting parts 13P, and also removes the pair of left and right connecting pins P2 connecting the pair of left and right frame rear connecting parts 122Q to the pair of left and right weight rear connecting parts 13Q.

[0061] Furthermore, the worker uses the auxiliary crane to move the base weight 13A to the rear position shown in Figures 6 and 7, and connects the pair of left and right frame rear connecting portions 122Q and the pair of left and right weight front connecting portions 13P with the pair of left and right connecting pins P2, respectively.

[0062] Next, the worker connects the pair of left and right upper links 722 of the weight-side link 72 to the sheave-side link 71 using the pair of left and right connecting pins P1, and connects the pair of left and right lower links 723 of the weight-side link 72 to the pair of left and right weight rear connecting parts 13Q using the pair of left and right connecting pins P2. As a result, the base weight 13A is supported by the revolving frame 120 at the rear position.

[0063] Furthermore, the worker places the counterweight 13B, which had been evacuated to the ground, on the base weight 13A again using the auxiliary crane and fixes it with a fixing device (not shown). As a result, the weight unit 13 is fixed in the rear position.

[0064] As described above, according to this embodiment, by changing the connection points of the base weight 13A in the multiple pairs of frame connection parts arranged on the revolving frame 120, it becomes possible to selectively attach the base weight 13A to the revolving frame 120 at least between the front connection state (front position) and the rear connection state (rear position), and the counterweight 13B can be arranged at two (multiple) positions in the front-rear direction. Therefore, in response to changes in lifting conditions including the length of the boom 16 and the jib 18 and the weight of the suspended load, it becomes possible to change the magnitude of the moment applied to the upper rotating body 12 by the counterweight 13B and the base weight 13A without changing the weight of the counterweight 13B mounted on the base weight 13A, and it becomes possible to maintain the stability of the crane 10 (upper rotating body 12). In addition, the link unit 70 can connect a pair of left and right weight rear connecting portions 13Q (portions of the base weight 13A that protrude rearward from the revolving frame 120) located rearward of the revolving frame 120 to the sheave mounting portion 122S of the upper revolving body 12, thereby preventing the rear portion of the base weight 13A from bending downward.

[0065] In addition, in this embodiment, when the link unit 70 connects the sheave mounting portion 122S to the pair of left and right weight rear connecting portions 13Q in the rear connected state, the connection destination of the link unit 70 (frame auxiliary connecting portion) is arranged next to the sheave mounting portion 122S at the rear end of the swivel frame 120 so that at least a downward force is applied to the sheave block 42 due to the weight of the counterweight 13B (weight unit 13).

[0066] According to this configuration, when the hoisting device 16T supports the boom 16, an upward force is applied to the rear end of the revolving frame 120 through the sheave block 42, while the link unit 70 connects the sheave mounting portion 122S to the pair of left and right weight rear connecting portions 13Q, so that at least a downward force is applied to the sheave block 42 by the weight of the counterweight 13B. Therefore, the above-mentioned upward and downward forces are partially offset, so that the sheave block 42 of the hoisting device 16T functions to support the counterweight 13B and the base weight 13A, and the rear end of the revolving frame 120 and the base weight 13A are prevented from bending downward.

[0067] In other words, the weight of the counterweight 13B is applied downward to the sheave block 42 through the link unit 70, and the weight of the boom 16 and the suspended load acts on the sheave block 42 so that the boom tip of the boom 16 pulls the sheave block 42 upward. Therefore, the sheave block 42 connected to the boom tip functions to support the pair of left and right weight rear connectors 13Q through the link unit 70, so that the portion of the base weight 13A located rearward of the revolving frame 120 is prevented from bending downward, and the stability of the upper revolving body 12 can be improved.

[0068] Furthermore, in this embodiment, when the counterweight 13B is placed on the base weight 13A, the weights of the base weight 13A and the counterweight 13B are applied at least downward to the sheave support pin 122A through the base weight 13A, the pair of left and right weight rear connectors 13Q, and the link unit 70. On the other hand, when the hoisting device 16T supports the boom 16, at least an upward force is applied to the sheave support pin 122A through the boom tip, the boom guy line 24, the sheave block 40, the boom hoist rope 38, and the sheave block 42. As a result, the sheave block 42 connected to the boom tip directly supports the pair of left and right weight rear connecting parts 13Q via the sheave support pin 122A and functions as if the sheave block 42 is positioned at the rear end of the base weight 13A, which further prevents the portion of the base weight 13A located rearward of the rotating frame 120 from bending downward, further increasing the stability of the upper rotating body 12.

[0069] In this embodiment, the counterweight 13B can be placed on the right and left mounting surfaces 13HR and 13HL of the base weight 13A arranged on both the left and right sides of the revolving frame 120 when viewed from the front-rear direction, respectively, thereby improving the stability of the upper revolving body 12 in the left-right direction as well as the front-rear direction. In addition, by arranging the pair of weight-side links 72 in positions close to the sheave block 42 in the left-right direction, the transmission of force between the sheave block 42 and the link unit 70 via the sheave support pin 122A is facilitated, while the base weight 13A, which is wider in the left-right direction than the revolving frame 120, can be stably supported by the pair of left and right lower links 723 of the weight-side link 72 of the link unit 70.

[0070] The crane 10 according to one embodiment of the present invention has been described above. However, the present invention is not limited to these embodiments. For example, the present invention can take the following modified embodiments.

[0071] (1) In the above embodiment, the crane according to the present invention is not limited to the crane 10 described above, and may be a crane having another structure, such as a tower crane. Also, it is not limited to a crane that can move on the ground. Also, the structure of the crane 10 is not limited to that shown in FIG. 1, and may be another structure, such as a structure without a jib.

[0072] (2) In the above embodiment, the sheave block 42 and the link unit 70 are supported by the same sheave support pin 122A, but the present invention is not limited to this. Fig. 11 and Fig. 12 are a plan view and a side view of the revolving frame 120 and the sheave-side link 71 of the crane according to the first modified embodiment of the present invention. In this modified embodiment, a pair of left and right link support parts 70S (frame auxiliary connecting parts) are arranged on the left and right sides of the pair of left and right sheave mounting parts 122S on the rear horizontal plate 121B of the revolving frame 120. Each link support part 70S can be connected to the sheave-side link 71 in the previous embodiment by a connecting pin P1.

[0073] Meanwhile, in this modified embodiment, as in the previous embodiment, the sheave block 42 is attached to the sheave mounting portion 122S. That is, the pair of left and right link support portions 70S are arranged side by side in the left-right direction on the sheave block 42 at the rear end portion of the revolving frame 120.

[0074] Even in this configuration, the mounting position of the link unit 70 (link support portion 70S) is set close to the mounting position of the sheave block 42 (sheave mounting portion 122S), so that the force acting on the sheave block 42 under the load of the boom 16 is transmitted to the link unit 70 through the revolving frame 120 (rear cross plate 121B). According to this configuration, the hoisting device 16T and the link unit 70 are arranged so as to be continuously connected in the front-rear direction through the sheave block 42 and the sheave mounting portion 122S when viewed from the left-right direction. Therefore, the sheave block 42 of the hoisting device 16T functions to support the counterweight 13B and the base weight 13A via the rear end portion of the revolving frame 120, and downward bending of the rear portion of the base weight 13A can be further suppressed.

[0075] 13 and 14 are plan and side views of a revolving frame 120 and a sheave-side link 71 of a crane according to a second modified embodiment of the present invention. In this modified embodiment, a pair of left and right link support parts 70S (auxiliary frame connecting parts) are arranged on the rear side of a pair of left and right sheave mounting parts 122S on the rear horizontal plate 121B of the revolving frame 120. The sheave-side link 71 in the previous embodiment can be connected to each link support part 70S by a connecting pin P1.

[0076] In this modified embodiment, as in the previous embodiment, the sheave block 42 is attached to the sheave mounting portion 122S. That is, the pair of left and right link support portions 70S are arranged side by side in the front-rear direction on the sheave block 42 at the rear end portion of the revolving frame 120.

[0077] Even in this configuration, when viewed from the left-right direction, the hoisting device 16T and the link unit 70 are arranged so as to be connected in the front-rear direction through a part of the revolving frame 120. Therefore, the sheave block 42 of the hoisting device 16T functions to support the counterweight 13B and the base weight 13A via the rear end of the revolving frame 120, further preventing the rear portion of the base weight 13A from bending downward.

[0078] (3) In the above embodiment, the link unit 70 is described as being composed of a pair of left and right sheave side links 71 and weight side links 72, but the present invention is not limited to this. The link unit 70 may be composed of an integrated unit without being separated into the sheave side link 71 and the weight side link 72. In addition, the structure of the sheave block 42 (spreader) is not limited to the structure in Figures 9 and 10, and may be composed of another structure.

[0079] (4) Furthermore, in the above embodiment, a pair of left and right frame front connectors 122P and a pair of left and right frame rear connectors 122Q are disposed on the revolving frame 120, but the present invention is not limited to this. The revolving frame 120 may be provided with three or more pairs of frame connectors in the front and rear. In this case, the weight unit 13 can be disposed in three or more positions in the front-rear direction. [Explanation of symbols]

[0080] 10. Crane 10S Swivel Bearing 12 Upper rotating body (aircraft) 120 Swivel frame (frame) 121A side plate 121B Rear horizontal plate 121S Boom foot support part 121T Mast foot support 122A Sheave support pin (support pin) 122B Sheave support (pin support) 122P Frame front connection 122Q Frame rear connection part 122S Sheave mounting part (frame auxiliary connection part) 13 Weight unit 13A Base Weight 13B Counterweight 13H Placement surface 13HR Right side placement surface 13HL Left placement surface 13P Weight front connection part 13Q Weight rear connection part 14 Undercarriage 15 Cab 16 Boom (elevating body) 16S Boom Foot Pin 16T hoisting equipment 18 Jib 20 Mast 24 Boom guy lines (guy lines) 30 Boom hoisting winch (boom hoisting winch) 34 Main winch 38 Boom hoisting rope (boom hoisting rope) 40 Sheave block (mast side sheave block) 42 Sheave block (frame connection part, frame side sheave block) 420 Sheaves 42H sheave holder 42T sheave shaft 44 Jib hoisting rope 46 Guide sheave 47 Sheave block 48 Sheave block 50 Main winding rope 57 Main Hook 58 Sheaves 70 Link unit (auxiliary connecting member) 70S Link support part (frame auxiliary connection part) 71 Sheave side link (first connecting member) 72 Weight side link (second connecting member) 721 Link Base Department 722 Upper link (upper connection part) 723 Lower link (lower connection part) CL central axis of rotation P1 Connecting pin P2 connecting pin

Claims

1. The aircraft and A hoisting body having a hoisting body base end portion supported on the aircraft body so as to be rotatable in a hoisting direction; A counterweight; a base weight having a mounting surface that allows the counterweight to be placed thereon, and selectively and detachably attached to the airframe in at least a front connected state in which the counterweight is attached to the airframe at a front position and a rear connected state in which the counterweight is attached to the airframe at a rear position that is located rearward of the front position and protrudes rearward from the airframe relative to the front position; an auxiliary connecting member capable of connecting a portion of the base weight disposed at the rear position in the rear connected state to the airframe and the airframe; A crane equipped with

2. An airframe; A hoisting body having a hoisting body base end portion supported on the aircraft body so as to be rotatable in a hoisting direction; A counterweight; a base weight having a placement surface on which the counterweight is placed, the base weight being detachably attached to the airframe at least at a front position and a rear position that is a position rearward of the front position and protrudes rearward from the airframe more than the front position; an auxiliary connecting member capable of connecting a portion of the base weight disposed at the rear position that protrudes rearward from the airframe to the airframe; Equipped with The airframe comprises: A frame, A plurality of pairs of frame connectors are arranged on the frame behind the undulating body, the plurality of pairs of frame connectors including a pair of left and right frame front connectors and a pair of left and right frame rear connectors arranged behind the pair of left and right frame front connectors; a frame auxiliary connection portion disposed at a rear end portion of the frame; having The base weight is A pair of left and right weight front connectors that can be selectively connected to the pair of left and right frame front connectors and the pair of left and right frame rear connectors; a pair of left and right weight rear connecting parts that are arranged rearward of the pair of left and right weight front connecting parts so as to be connectable to the pair of left and right frame rear connecting parts in a front connecting state in which the pair of left and right weight front connecting parts are connected to the pair of left and right frame front connecting parts, and a pair of left and right weight rear connecting parts that are arranged rearward of the frame in a rear connecting state in which the pair of left and right weight front connecting parts are connected to the pair of left and right frame rear connecting parts; having A crane, wherein the auxiliary connecting member is capable of connecting the frame auxiliary connecting portion and the pair of left and right weight rear connecting portions to each other in the rear connected state.

3. The undulating body further has an undulating body tip portion disposed on the opposite side to the undulating body base end portion, The apparatus further includes a lifting device that is supported by the frame at the rear of the undulating body and is connected to a tip end of the undulating body, and is capable of rotating the undulating body in a lifting direction, The hoisting device has a frame connection portion connected to a rear end of the frame such that the hoisting device supports the hoisting body in a state in which the hoisting body extends forward and upward from the fuselage, thereby applying at least an upward force to the rear end of the frame; 3. The crane according to claim 2, wherein the frame auxiliary connection portion is arranged next to the frame connection portion at the rear end portion of the frame so that at least a downward force is applied to the frame connection portion by the weight of the counterweight when the auxiliary connecting member connects the frame auxiliary connection portion and the pair of left and right weight rear connecting portions to each other.

4. the frame auxiliary connection portion includes a plurality of pin support portions arranged at intervals in the left-right direction at a rear end portion of the frame, and a support pin extending in the left-right direction to connect the plurality of pin support portions to each other, The lifting device is a mast having a mast base end portion supported on the frame rearward of the elevation body and forward of the frame auxiliary connection portion so as to be rotatable in an elevation direction, and a mast tip portion opposite to the mast base end portion; A guy line connecting the mast tip and the elevation body tip to each other; a mast side sheave block including a first sheave and supported on the mast tip; a frame side sheave block including a second sheave, supported by the support pin of the frame auxiliary connecting portion, and constituting the frame connecting portion; a hoisting rope stretched between the first sheave of the mast side sheave block and the second sheave of the frame side sheave block; a hoisting winch capable of changing the distance between the mast side sheave block and the frame side sheave block by winding and unwinding the hoisting rope, thereby hoisting the hoisting body together with the mast, The crane according to claim 3 , wherein the auxiliary connecting member connects the support pin of the frame auxiliary connecting portion and the pair of left and right weight rear connecting portions to each other.

5. The base weight has a dimension such that it protrudes on both sides of the frame in the left-right direction when viewed from the front-rear direction, The support surface includes a right support surface and a left support surface that are arranged on both the left and right sides of the frame when viewed from the front-rear direction and allow the counterweight to be placed thereon, The auxiliary connecting member is a pair of left and right first connecting members respectively connected to the support pins on the left and right sides of the frame side sheave block; a second connecting member including a pair of left and right upper connecting portions respectively connected to the pair of left and right first connecting members, and a pair of left and right lower connecting portions respectively connected to the pair of left and right weight rear connecting portions on the outer sides of the pair of left and right first connecting members; 5. The crane of claim 4, further comprising:

6. The crane according to claim 3 , wherein the frame auxiliary connector is fixed to the frame so as to be arranged side by side with the frame connection portion in the left-right direction at a rear end of the frame.

7. The crane according to claim 3 , wherein the frame auxiliary connector is fixed to the frame so as to be arranged side by side with the frame connection portion in the front-rear direction at a rear end of the frame.

Images