Construction machinery

Abstract

To provide a construction machine capable of improving work efficiency and safety in using a jib.SOLUTION: In a construction machine, a jib is rotatable with respect to a boom around a first position of a front end part of the boom and a boom-side link is connected to the front end part of the boom at a second position positioned on the side where the boom is raised with respect to the first position. A tension rod includes a rod main body connected to the jib and an extension mounted on a rear end part of the rod main body to be connectable to the boom-side link such that the rod length is changed in accordance with the movement of the extension along an axial direction. A stopper member can be mounted on the rear end part of the rod main body while protruding in the rear side from the rod main body and sandwiches the extension from both sides in the width direction of the jib while protruding from the rod main body.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to construction machinery.

Background Art

[0002] Patent Document 1 discloses a crane as a construction machine. In this crane, a jib is provided together with a boom that can be raised and lowered. A boom head is provided at the front end of the boom, and a boom-side link is connected to the boom head. Further, in the boom, a boom-side coupling is provided on the rear side with respect to the boom head. And the jib is provided with a jib-side coupling, and the front end of the tension rod is connected thereto. When using the jib, the jib-side coupling is connected to the boom-side coupling, and with the jib arranged along the longitudinal direction of the boom on the lower surface of the boom, the rear end of the jib is connected to the boom head. Then, the rear end of the tension rod is connected to the boom-side link. And with the jib connected to the boom head and the tension rod connected to the boom-side link, the connection of the jib-side coupling to the boom-side coupling is released. Thereby, the jib becomes a state of hanging down from the connection position to the boom head, and becomes rotatable with respect to the boom about the connection position to the boom head. And the jib is used by raising or lowering the jib with respect to the boom in a state where the jib is rotatable about the connection position to the boom head.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a construction machine equipped with a jib as in Patent Document 1, it is required to improve the work efficiency during the use of the jib, including operations such as connecting a tension rod to the boom side link. Further, it is required to improve the safety during the use of the jib.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a construction machine capable of improving work efficiency and safety during the use of a jib.

Means for Solving the Problems

[0006] To achieve the above object, a construction machine according to an aspect of the present invention includes a boom that can be raised and lowered and can be extended and contracted in the longitudinal direction, the boom having a boom lower surface facing the lowering side, a jib that can be arranged along the longitudinal direction of the boom on the boom lower surface of the boom and can be connected to the front end portion of the boom at a first position, the jib being rotatable with respect to the boom about the first position, a boom side link connected to the front end portion of the boom at a second position located on the side where the boom rises with respect to the first position, a rod body having a front end connected to the jib, an extension attached to the rear end portion of the rod body and connectable to the boom side link, a tension rod whose rod length in the axial direction changes in response to the movement of the extension along the axial direction with respect to the rod body, and a stopper member that can be attached to the rear end portion of the rod body in a state of protruding rearward from the rod body and sandwiches the extension from both sides in the width direction of the jib that intersects both the axial direction of the tension rod and the raising and lowering direction of the jib in a state of protruding rearward from the rod body.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a construction machine capable of improving work efficiency and safety during the use of a jib.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings.

[0010] (First Embodiment) Figures 1 to 3 show a crane 1 according to a first embodiment as an example of a construction machine according to the embodiment. As shown in Figures 1 to 3, the crane 1 includes a traveling body 2 and a slewing body 3 installed on the traveling body 2. The slewing body 3 is rotatable with respect to the traveling body 2 about a slewing axis parallel or substantially parallel to the vertical direction. The slewing body 3 includes a slewing platform 5, a driver's cab 6, a boom 11, a jib 12, a pair of tension rods 13, and a pair of boom side links 15. The slewing platform 5, the driver's cab 6, the boom 11, the jib 12, the tension rods 13, and the boom side links 15 rotate together with respect to the traveling body 2. In the driver's cab 6, the operator operates the crane 1 and the like. Further, on the traveling body 2, a pair of outriggers 8A are provided at the front side portion, and a pair of outriggers 8B are provided at the rear side portion.

[0011] The boom 11 has a rear end and a front end, and extends along the longitudinal direction (front-rear direction) from the rear end to the front end. The rear end portion of the boom 11 is connected to the slewing platform 5, and the boom 11 is capable of pitching with respect to the slewing platform 5. Note that the crane 1 is provided with a telescopic boom pitching cylinder (not shown). One end of the boom pitching cylinder is connected to the boom 11, and the other end is connected to the slewing platform 5. By extending or contracting the boom pitching cylinder, the boom 11 rises or falls with respect to the slewing platform 5.

[0012] Figures 4 to 7 show the configurations of the boom 11, the jib 12, the tension rods 13, the boom side links 15, and the like. In Figure 7, the state of Figure 1 is shown with a part enlarged. In the boom 11, one side in the longitudinal direction is defined as the front side (arrow C1 side), and the side opposite to the front side is defined as the rear side (arrow C2 side). Further, in the boom 11, a pitching direction (directions indicated by arrows Y1 and Y2) that intersects (is orthogonal or substantially orthogonal) to the longitudinal direction, and a width direction (a direction orthogonal or substantially orthogonal to the paper surface in Figures 1 to 7) that intersects (is orthogonal or substantially orthogonal) to both the longitudinal direction and the pitching direction are defined. In the boom 11, one side in the pitching direction is the side where the boom 11 rises (arrow Y1 side), and the side opposite to the side where the boom 11 rises is the side where the boom 11 falls (arrow Y2 side).

[0013] As shown in FIGS. 4 to 7 and the like, the outer surface of the boom 11 has a boom upper surface 21, a boom lower surface 22, a pair of boom side surfaces 23, and a boom front end surface 25. In the boom 11, each of the boom upper surface 21, the boom lower surface 22, and the boom side surfaces 23 extends along the longitudinal direction from the rear end to the front end. Further, the boom front end surface 25 forms the front end of the boom 11, and the boom front end surface 25 faces the front side of the boom 11. The boom upper surface 21 faces the side where the boom 11 rises, and the boom lower surface 22 faces the side where the boom 11 falls. In a state where the longitudinal direction of the boom 11 coincides with the horizontal direction, the boom upper surface 21 faces the vertically upper side, and the boom lower surface 22 faces the vertically lower side.

[0014] Also, each of the boom side surfaces 23 faces outward in the width direction of the boom 11, and the pair of boom side surfaces 23 face opposite sides with respect to each other in the width direction of the boom 11. Each of the boom upper surface 21, the boom lower surface 22, and the boom front end surface 25 extends along the width direction of the boom 11 between the pair of boom side surfaces 23. Further, each of the boom side surfaces 23 and the boom front end surface 25 extends along the undulating direction of the boom 11 between the boom upper surface 21 and the boom lower surface 22. A boom head 17 is provided at the front end portion (tip portion) of the boom 11. In the boom 11, the boom head 17 forms the front end of the boom 11 and the boom front end surface 25.

[0015] In addition, in the present embodiment, the boom 11 is telescopically extendable in the longitudinal direction. The boom 11 includes a base boom member 16 and one or more movable boom members 18 that are movable along the longitudinal direction of the boom 11 with respect to the base boom member 16. In the present embodiment, five movable boom members 18 are provided on the boom 11. Further, in the present embodiment, the rear end of the boom 11 is formed by the base boom member 16, and the front end of the boom 11 and the boom head 17 are formed by the most forward movable boom member 18. Inside the boom 11, a boom telescopic cylinder (not shown) is provided. By extending or contracting the boom telescopic cylinder while the boom telescopic cylinder is connected to any one of the movable boom members 18, the boom 11 extends or contracts in the longitudinal direction.

[0016] The boom 11 is capable of pitching with respect to the turntable 5 between the most raised maximum raised position and the most lowered maximum lowered position. In an example such as FIGS. 1 to 7, in each of the states of FIG. 2, FIG. 3, and FIG. 6, the boom 11 is located at the maximum raised position, and in the states of FIG. 1 and FIG. 7, the boom 11 is located at the maximum lowered position. Then, in each of the states of FIG. 4 and FIG. 5, the boom 11 is located at an intermediate position between the maximum raised position and the maximum lowered position. Here, the pitching angle of the longitudinal direction of the boom 11 with respect to the horizontal direction is defined. When the boom 11 forms an elevation angle with respect to the horizontal direction, the pitching angle is a positive value, and when the boom 11 forms a depression angle with respect to the horizontal direction, the pitching angle is a negative value.

[0017] In an example such as FIGS. 1 to 7, in a state where the boom 11 is in the fully raised position, the longitudinal direction of the boom 11 forms an elevation angle with respect to the horizontal direction, and the undulation angle of the boom 11 is, for example, any angle of 80° or more and less than 90°. For this reason, in the boom 11 in the fully raised position, the front side part in the longitudinal direction is located more vertically upward. Further, in a state where the boom 11 is in the fully lowered position, the longitudinal direction of the boom 11 forms a depression angle with respect to the horizontal direction, and the undulation angle of the boom 11 becomes a negative value. For this reason, in the boom 11 in the fully lowered position, the front side part in the longitudinal direction is located more vertically downward. In addition, in an example, in a state where the boom is in the fully lowered position, the longitudinal direction of the boom 11 may coincide with or substantially coincide with the horizontal direction, and the undulation angle of the boom 11 may be 0° or substantially 0°.

[0018] Further, one or more boom-side couplings (not shown) are provided on the boom 11. In the boom 11, the boom-side coupling is arranged on the rear side with respect to the boom head 17 and is provided on the base boom member 16. Guide sheaves 31, 32, a top sheave (boom top sheave) 33, and a loose pulley sheave 35 are attached to the boom head 17. The guide sheave 32 is attached to the boom head 17 (front end of the boom 11) via a shaft (shaft for guide sheave) 36, and the top sheave 33 is attached to the boom head 17 (front end of the boom 11) via a shaft (shaft for top sheave) 37. Each of the shafts 36, 37 extends along the width direction of the boom 11. The guide sheaves 31, 32 and the shaft 36 are arranged closer to the boom upper surface 21, that is, on the side where the boom 11 rises, with respect to the top sheave 33, the loose pulley sheave 35 and the shaft 37. And the guide sheave 32, the loose pulley sheave 35 and the shaft 36 are arranged on the front side with respect to the guide sheave 31, the top sheave 33 and the shaft 37.

[0019] In this embodiment, a main winch (not shown) of the slewing platform 5 extends a main hoisting rope (not shown), and the main hoisting rope extends from the rear side to the front side on the upper surface 21 of the boom. Then, the main hoisting rope is hung on a guide sheave 31 and a top sheave 33, and the main hook 42 is suspended from the top sheave 33 via the main hoisting rope. Further, in this embodiment, an auxiliary winch (not shown) of the slewing platform 5 extends an auxiliary hoisting rope (not shown), and the auxiliary hoisting rope extends from the rear side to the front side on the upper surface 21 of the boom. Then, in a state where the jib 12 is not in use (when the jib 12 is not used), the auxiliary hoisting rope is hung on a guide sheave 32 and a luffing sheave 35, and the auxiliary hook 45 is suspended from the luffing sheave 35 via the auxiliary hoisting rope.

[0020] The jib 12 has a rear end and a front end, and extends along the longitudinal direction (front-rear direction) from the rear end to the front end. In the jib 12, one side in the longitudinal direction is defined as the front side (arrow C3 side), and the side opposite to the front side is defined as the rear side (arrow C4 side). Further, in the jib 12, a luffing direction (directions indicated by arrows Y3 and Y4) that intersects (is orthogonal or substantially orthogonal) with the longitudinal direction, and a width direction (a direction orthogonal or substantially orthogonal to the paper surface in FIGS. 1 to 7) that intersects (is orthogonal or substantially orthogonal) with both the longitudinal direction and the luffing direction are defined. In the jib 12, one side in the luffing direction is the side where the jib 12 rises (arrow Y3 side), and the side opposite to the side where the jib 12 rises is the side where the jib 12 falls (arrow Y4 side). Further, in the crane 1, the width direction of the jib 12 coincides or substantially coincides with the width direction of the boom 11.

[0021] As shown in FIGS. 4 to 7 and the like, the outer surface of the jib 12 has a jib upper surface 46, a jib lower surface 47, and a pair of jib side surfaces 48. In the jib 12, each of the jib upper surface 46, the jib lower surface 47, and the jib side surface 48 extends along the longitudinal direction from the rear end to the front end. The jib upper surface 46 faces the side where the jib 12 rises, and the jib lower surface 47 faces the side where the jib 12 falls. Also, each of the jib side surfaces 48 faces outward in the width direction of the jib 12, and the pair of jib side surfaces 48 face opposite sides with respect to each other in the width direction of the jib 12. Each of the jib upper surface 46 and the jib lower surface 47 extends along the width direction of the jib 12 between the pair of jib side surfaces 48. Also, each of the jib side surfaces 48 extends along the undulating direction of the jib 12 between the jib upper surface 46 and the jib lower surface 47.

[0022] In the present embodiment, the jib 12 is stretchable in the longitudinal direction. The jib 12 includes a base jib member 51 and a movable jib member 52 that is movable along the longitudinal direction of the jib 12 with respect to the base jib member 51. In the present embodiment, the rear end of the jib 12 is formed by the base jib member 51, and the front end of the jib 12 is formed by the movable jib member 52. When the movable jib member 52 moves along the longitudinal direction of the jib 12 with respect to the base jib member 51, the jib 12 extends or contracts in the longitudinal direction.

[0023] Also, in an example of FIGS. 1 to 7 and the like, a jib expansion and contraction cylinder or the like is not provided. For example, the movable jib member 52 is manually moved to extend or contract the jib 12. In an example of FIGS. 1 to 7 and the like, only one movable jib member 52 is provided, but a plurality of movable jib members may be provided. In this case, the most forward movable jib member forms the front end of the jib 12. Also, in one example, no movable jib member is provided on the jib 12, and the jib 12 may be formed only from the base jib member 51. In this case, the jib 12 is not stretchable in the longitudinal direction.

[0024] FIG. 8 shows the configurations of the jib 12, the tension rod 13, etc. Here, FIG. 8 is a perspective view, and the directions indicated by the arrow W1 and the arrow W2 correspond to the width direction of the jib 12. As shown in FIGS. 4 to 8, etc., a pair of jib feet 53 are provided at the rear end of the base jib member 51 of the jib 12. The pair of jib feet 53 are arranged apart from each other in the width direction of the jib 12. For this reason, the rear end of the base jib member 51 is formed in a bifurcated shape, and a space is formed between the pair of jib feet 53 in the width direction of the jib 12. In an example of FIGS. 1 to 8, etc., each of the jib feet 53 forms the rear end of the jib 12. The rear end of each of the jib feet 53 can be engaged with the shaft 37 for the top sheave 33.

[0025] A foot pin 55 can be attached to each of the jib feet 53. In each of the jib feet 53, it is prevented that the engagement with the shaft 37 is released by the attached foot pin 55. For this reason, when the jib feet 53 are engaged with the shaft 37, by attaching the foot pin 55 to each of the jib feet 53, the jib 12 is connected to the boom head 17 (the front end of the boom 11). In the present embodiment, the shaft 37 for the top sheave 33 is the first position where the jib 12 is connected to the boom head 17. In a state where the jib 12 is connected to the boom head 17 at the first position (shaft 37), the jib 12 moves in conjunction with the extension or contraction in the longitudinal direction of the boom 11. On the other hand, in a state where the jib 12 is not connected to the boom head 17 at the first position (shaft 37), even if the boom 11 extends or contracts in the longitudinal direction, the jib 12 does not move.

[0026] In addition, one or more jib-side couplings are provided on the base jib member 51 of the jib 12. In the jib 12, the same number of jib-side couplings as the boom-side couplings are provided. Each of the jib-side couplings can be connected to a corresponding one of the boom-side couplings. Further, a slide bracket 60 is attached to the outer surface of the base jib member 51. The slide bracket 60 is movable along the longitudinal direction of the jib 12 with respect to the base jib member 51.

[0027] Also, a pair of jib elevation cylinders 61 are attached to the base jib member 51 of the jib 12. Each of the jib elevation cylinders 61 is disposed on a corresponding one of the pair of jib side surfaces 48. Each of the jib elevation cylinders 61 extends in parallel with each other along the longitudinal direction of the jib 12 and is extendable and contractible in the longitudinal direction of the jib 12. The front end (one end) of each of the jib elevation cylinders 61 is connected to the slide bracket 60. Also, the rear end (the other end) of each of the jib elevation cylinders 61 is connected to the base jib member 51. Note that the connection position of each of the jib elevation cylinders 61 to the base jib member 51 is located on the rear side of the jib 12 with respect to the slide bracket 60 and on the front side of the jib 12 with respect to the jib foot 53.

[0028] The slide bracket 60 is located at the rearmost position on the rearmost side when the pair of jib elevation cylinders 61 are in the most contracted state. And the slide bracket 60 is located at the foremost position on the foremost side when the pair of jib elevation cylinders 61 are in the most extended state. Therefore, the slide bracket 60 is movable along the longitudinal direction of the jib 12 between the rearmost position and the foremost position. Note that even when the slide bracket 60 is located at the rearmost position, the slide bracket 60 is located on the front side of the jib 12 with respect to the jib foot 53. Also, even when the slide bracket 60 is located at the foremost position, the slide bracket 60 is located on the outer surface of the base jib member 51, and the slide bracket 60 is not located on the outer surface of the movable jib member 52.

[0029] The pair of tension rods 13 extend in parallel with each other and are arranged on the side where the jib 12 rises (the side facing the upper surface 46 of the jib) with respect to the jib 12. Each of the tension rods 13 has a front end and a rear end, and extends along the axial direction from the front end (one end) to the rear end (the other end). Each of the tension rods 13 extends from the rear end to the front end toward the front side of the jib 12. The axial direction of each of the tension rods 13 intersects with the tilting direction of the jib 12 and also intersects with (is perpendicular or substantially perpendicular to) the width direction of the jib 12.

[0030] The pair of tension rods 13 are arranged apart from each other in the width direction of the jib 12. The front end of each of the tension rods 13 is connected to the slide bracket 60. Therefore, the front end of each of the tension rods 13 is connected to the base jib member 51 of the jib 12 via the slide bracket 60. Further, when the slide bracket 60 moves along the longitudinal direction of the jib 12 due to the extension or contraction of the pair of jib tilting cylinders 61, the connection position of the front end of the tension rod 13 to the jib 12 changes along the longitudinal direction of the jib 12.

[0031] In addition, a pair of rod receivers (not shown) are provided on the base jib member 51 of the jib 12. Each of the rod receivers is formed on the upper surface 46 of the jib and is arranged apart from each other in the width direction of the jib 12. Each of the pair of rod receivers can engage with and support the corresponding one of the pair of tension rods 13. A top sheave (jib top sheave) 63 is attached to the movable jib member 52 of the jib 12. The top sheave 63 is arranged at the front end of the jib 12. In a state where work is being done using the jib 12 (when the jib 12 is in use), the rewinding rope extends from the guide sheave 32 at the front end of the boom 11 to the upper surface 46 of the jib. Then, the rewinding rope extends from the rear side to the front side on the upper surface 46 of the jib. Then, the rewinding rope is hung on the top sheave 63, and the compensating hook 45 is suspended from the top sheave 63 via the rewinding rope.

[0032] The pair of boom-side links 15 are attached to the boom head 17 and extend in parallel with each other. Each of the boom-side links 15 has a front end and a rear end, and extends along the axial direction from the front end (one end) to the rear end (the other end). The axial direction of each of the boom-side links 15 intersects (is perpendicular or substantially perpendicular) with the width direction of the boom 11 and the jib 12. The pair of boom-side links 15 are arranged apart from each other in the width direction of the jib 12. The front end of each of the boom-side links 15 can be connected to the corresponding rear end of one of the pair of tension rods 13. Therefore, each of the pair of tension rods 13 can be connected to the corresponding one of the pair of boom-side links 15.

[0033] The rear end of each of the boom-side links 15 is connected to the boom head 17 (the front end portion of the boom 11). In the present embodiment, the rear end of each of the boom-side links 15 is connected to the shaft 36 for the guide sheave 32. For this reason, the shaft 36 for the guide sheave 32 becomes the second position where the rear end of each of the boom-side links 15 is connected to the boom head 17. The second position (shaft 36) where each of the boom-side links 15 is connected to the boom head 17 is located on the side where the boom 11 rises with respect to the first position (shaft 37) where the jib 12 is connected to the boom head 17.

[0034] Each of the boom-side links 15 is rotatable with respect to the boom 11 about the second position which is the connection position to the boom head 17 (shaft 36). The boom-side link 15 is disposed on the front side of the boom 11 with respect to the boom head 17 and on the front side of the boom 11 with respect to the front end face 25 of the boom. By rotating about the second position, each of the boom-side links 15 approaches or moves away from the front side of the boom 11 with respect to the boom head 17. Therefore, by the rotation about the second position, the axial angle (acute angle) with respect to the undulating direction of the boom 11 changes for each of the boom-side links 15.

[0035] In addition, a pair of storage guides 65 are provided on the boom head 17 of the boom 11. The storage guides 65 are located on the side where the boom 11 lies down with respect to the second position (shaft 36) where the boom side link 15 is connected to the boom head 17. Each of the pair of boom side links 15 can engage with a corresponding one of the pair of storage guides 65 and is stored in a state of engaging with the corresponding one of the storage guides 65. Each of the boom side links 15 extends from the second position toward the side where the boom 11 lies down while engaging with the corresponding one of the storage guides 65. And in a state where each of the boom side links 15 engages with the corresponding one of the storage guides 65, the front end of each of the boom side links 15 is located on the side where the boom 11 lies down with respect to the storage guide 65.

[0036] As shown in FIGS. 1 to 8 and the like, a pair of stopper members 19 are provided on the crane 1. Each of the pair of stopper members 19 can be attached to a corresponding rear end portion of one of the pair of tension rods 13. FIGS. 9 to 12 show the configuration of one of the pair of tension rods 13 and one of the pair of stopper members 19. Note that the configuration of the other one of the pair of tension rods 13 is the same as the configuration shown in FIGS. 9 to 12 and the like, and the configuration of the other one of the pair of stopper members 19 is also the same as the configuration shown in FIGS. 9 to 12 and the like.

[0037] In FIGS. 9 to 12, the directions indicated by the arrows C5 and C6 correspond to the axial direction of the tension rod 13. And the side of the arrow C5 corresponds to the front side of the tension rod 13, and the side of the arrow C6 corresponds to the rear side of the tension rod 13. Also, in FIGS. 9 to 12, the side of the arrow Y5 corresponds to the side opposite to the side where the jib 12 is located, and the side of the arrow Y6 corresponds to the side where the jib 12 is located. Also, FIG. 9 is a perspective view, and the directions indicated by the arrows W1 and W2 correspond to the width direction of the jib 12. Also, in the crane 1, a pair of tension units are defined. Each of the pair of tension units is composed of a corresponding one of the pair of tension rods 13, a corresponding one of the pair of boom side links 15, and a corresponding one of the pair of stopper members 19.

[0038] As shown in FIGS. 9 to 12 and the like, each of the tension rods 13 includes a rod body 71 and an extension 72. In each of the tension rods 13, a front end is formed by the rod body 71, and a rear end is formed by the extension 72. Therefore, in each of the tension rods 13, the front end of the rod body 71 is connected to the jib 12 via the slide bracket 60. And in each of the tension rods 13, by extending or contracting the jib hoisting cylinder 61, the connection position of the front end of the rod body 71 to the jib 12 changes along the longitudinal direction of the jib 12.

[0039] In each of the tension rods 13, the dimension of the rod body 71 along the axial direction is much larger than the dimension of the extension 72 along the axial direction. Therefore, in each of the tension rods 13, the rod body 71 extends from the connection position to the jib 12 to the rear end portion. Also, in each of the tension rods 13, the extension 72 is disposed at the rear end portion, that is, the end portion opposite to the connection position to the jib 12. And in each of the tension units, the extension 72 of the tension rod 13 is connected to the boom side link 15. In each of the tension rods 13, a cylindrical portion 73 is formed at the rear end portion of the rod body 71, that is, the end portion of the rod body 71 opposite to the connection position to the jib 12. And in each of the tension rods 13, the extension 72 is attached to the cylindrical portion 73.

[0040] In an example such as FIGS. 9 to 12 etc., each cylindrical portion 73 of the tension rod 13 is formed from a pair of side plates 75 and a pair of connecting plates 76, and the internal space opens towards the rear side. In each of the tension rods 13, the pair of side plates 75 cover the internal space of the cylindrical portion 73 from opposite sides with respect to the width direction of the jib 12. And in each of the tension rods 13, one of the pair of connecting plates 76 covers the internal space of the cylindrical portion 73 from the side opposite to the side where the jib 12 is located, and the other of the pair of connecting plates 76 covers the internal space of the cylindrical portion 73 from the side where the jib 12 is located. Also, in each of the tension rods 13, each of the connecting plates 76 extends along the width direction of the jib 12 between the pair of side plates 75. In each of the tension rods 13, the extension 72 is attached to the cylindrical portion 73 with the extension 72 inserted into the internal space of the cylindrical portion 73. However, in each of the tension rods 13, the extension 72 protrudes rearward from the opening of the cylindrical portion 73.

[0041] In each of the tension rods 13, a hole 77 is formed at the rear end of the extension 72, and the hole 77 penetrates the extension 72 along the width direction of the jib 12. In each of the tension rods 13, the hole 77 of the extension 72 is located on the rear side with respect to the rear end of the cylindrical portion 73, that is, with respect to the rear end of the rod body 71. Each extension 72 of the tension rod 13 is connected at the hole 77 to a corresponding one of the pair of boom side links 15. Also, a long hole 78 is formed on the front side of each extension 72 of the tension rod 13 with respect to the hole 77. In each of the tension rods 13, the long hole 78 is formed in a long hole shape with a large dimension along the axial direction and penetrates the extension 72 along the width direction of the jib 12.

[0042] In each of the tension rods 13, the extension 72 is attached to the cylindrical portion 73 (rear end portion) of the rod body 71 via the connecting pins 81 and 82. In each of the tension rods 13, the connecting pin 81 is attached to the cylindrical portion 73 and penetrates through the pair of side plates 75 along the width direction of the jib 12. Also, in each of the tension rods 13, the connecting pin 81 is inserted into the elongated hole 78 of the extension 72 in the internal space of the cylindrical portion 73.

[0043] In each of the tension rods 13, pin holes 83 and 85 are formed in each of the pair of side plates 75 of the cylindrical portion 73. In each of the tension rods 13, each of the pin holes 83 and 85 extends along the width direction of the jib 12 from the outer surface of the cylindrical portion 73 to the inner surface of the cylindrical portion 73. Also, in each cylindrical portion 73 of each of the tension rods 13, each of the pin holes 83 is located on the front side with respect to the attachment position (fixed position) of the connecting pin 81, and each of the pin holes 85 is located on the rear side with respect to the attachment position of the connecting pin 81. For this reason, in each of the tension rods 13, in the cylindrical portion 73 (rear end portion) of the rod body 71, the pin hole (second pin hole) 85 is formed on the rear side with respect to the pin hole (first pin hole) 83.

[0044] In each of the tension rods 13, the connecting pin 82 is removably attached to the cylindrical portion 73 and the extension 72. The connecting pin 82 can be attached to the cylindrical portion 73 of the rod body 71 at each of the pin holes 83 and 85. In each of the tension rods 13, with the connecting pin 82 removed, the extension 72 can move forward until the front end of the extension 72 abuts against the rod body 71 (the end opposite to the opening of the cylindrical portion 73) from the rear side within the internal space of the cylindrical portion 73. And in each of the tension rods 13, with the connecting pin 82 removed, the extension 72 can move backward until the connecting pin 81 abuts against the extension 72 (the edge of the long hole 78) at the front end of the long hole 78. For this reason, in each of the tension rods 13, with the connecting pin 82 removed, when the extension 72 moves relative to the rod body 71, the protruding amount of the extension 72 from the cylindrical portion 73 to the rear side changes, and the rod length along the axial direction changes. In the state where the connecting pin 82 is removed, the rod length of each of the tension rods 13 can vary between the minimum rod length Lmin shown in FIG. 10 and the maximum rod length Lmax shown in FIG. 12 and the like.

[0045] Also, in each of the tension rods 13, with the connecting pin 82 inserted through the pin holes 83 in the pair of side plates 75 of the cylindrical portion 73, the connecting pin 82 is inserted through the long hole 78 of the extension 72. In each of the tension rods 13, when the connecting pin 82 is attached to the cylindrical portion 73 of the rod body 71 at the pin holes 83, the movement of the extension 72 relative to the rod body 71 along the axial direction is restricted. For this reason, in the state where the connecting pin 82 is attached to the cylindrical portion 73 of the rod body 71 at the pin holes (the first pin holes) 83, each of the tension rods 13 cannot be extended or contracted, and the rod length of each of the tension rods 13 is maintained at the minimum rod length Lmin shown in FIG. 10 and the like.

[0046] In each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 83, the front end of the extension 72 abuts against the rod body 71 (the bottom of the cylindrical portion 73) from the rear side within the internal space of the cylindrical portion 73, so that the forward movement of the extension 72 is restricted. Also, in each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 83, the connecting pin 82 inserted through the pin hole 83 of the cylindrical portion 73 abuts against the extension 72 (the edge of the long hole 78) at the front end of the long hole 78 of the extension 72, so that the backward movement of the extension 72 is restricted.

[0047] In each of the tension rods 13, in a state where the connecting pin 82 is inserted through the pin holes 85 of the pair of side plates 75 of the cylindrical portion 73, the connecting pin 82 is inserted through the long hole 78 of the extension 72. In each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 of the rod body 71 through the pin hole (the second pin hole) 85, the extension 72 is axially movable with respect to the rod body 71. And in each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 85, when the extension 72 moves with respect to the rod body 71, the protruding amount of the extension 72 from the cylindrical portion 73 to the rear side changes, and the rod length along the axial direction changes.

[0048] In each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 85, the rod length changes between a predetermined rod length La shown in FIG. 11 etc. and a maximum rod length Lmax shown in FIG. 12 etc. Here, the predetermined rod length La is longer than the minimum rod length Lmin and shorter than the maximum rod length Lmax. In an example of FIGS. 9 to 12 etc., the predetermined rod length La is slightly longer than the minimum rod length Lmin.

[0049] In each of the tension rods 13, when the rod length contracts to a predetermined rod length La in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 85, the connecting pin 82 abuts on the extension 72 (the edge of the long hole 78) at the rear end of the long hole 78 of the extension 72. Therefore, the forward movement of the extension 72 is restricted. For this reason, in each of the tension rods 13, in a state where the connecting pin 82 is connected to the cylindrical portion 73 through the pin hole 85, further contraction of the rod length from the predetermined rod length La is suppressed, and the predetermined rod length La is the minimum value of the rod length in a state where the connecting pin 82 is inserted through the pin hole (second pin hole) 85.

[0050] Also, in each of the tension rods 13, when the rod length extends to the maximum rod length Lmax in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 85, the connecting pin 81 abuts on the extension 72 (the edge of the long hole 78) at the front end of the long hole 78 of the extension 72. Therefore, the backward movement of the extension 72 is restricted. For this reason, in each of the tension rods 13, in a state where the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole 85, further extension of the rod length from the maximum rod length Lmax is suppressed.

[0051] Also, in each of the tension rods 13, in a state where the rod length becomes the minimum rod length Lmin, the pin hole 85 of the cylindrical portion 73 is displaced rearward with respect to the long hole 78 of the extension 72. For this reason, in a state where the rod length becomes the minimum rod length Lmin, in each of the tension rods 13, the connecting pin 82 inserted through the pin hole (second pin hole) 85 cannot be inserted into the long hole 78. However, in a state where the rod length becomes the minimum rod length Lmin, in each of the tension rods 13, the connecting pin 82 inserted through the pin hole (first pin hole) 83 can be inserted into the long hole 78.

[0052] Also, in each of the tension rods 13, in a state where the rod length is either equal to or greater than a predetermined rod length La and equal to or less than a maximum rod length Lmax, or in a state of being extended from a minimum rod length Lmin, the pin hole (first pin hole) 83 of the cylindrical portion 73 is displaced forward with respect to the elongated hole 78 of the extension 72. For this reason, when extending from the minimum rod length Lmin, in each of the tension rods 13, the connecting pin 82 inserted through the pin hole 83 cannot be inserted into the elongated hole 78. However, by extending from the minimum rod length Lmin, in each of the tension rods 13, the connecting pin 82 inserted through the pin hole (second pin hole) 85 can be inserted into the elongated hole 78.

[0053] In addition, in each of the tension rods 13, a protruding piece 86 that protrudes on the outer peripheral surface of the cylindrical portion 73 is formed on the side opposite to the side where the jib 12 is located. In each of the tension rods 13, the protruding piece 86 is formed by a pair of side plates 75 of the cylindrical portion 73.

[0054] Also, in each of the tension rods 13, two pairs of slide plates 87, 88 are sandwiched between the cylindrical portion 73 and the extension 72 in the internal space of the cylindrical portion 73. In each of the tension rods 13, a pair of slide plates 87 are arranged on the front side with respect to the pair of slide plates 88. In each of the tension rods 13, each of the slide plates 87 is attached to the front end portion of the extension 72, and each of the slide plates 87, together with the extension 72, is movable along the axial direction with respect to the rod body 71. Also, in each of the tension rods 13, each of the slide plates 88 is fixed to the rear end portion of the cylindrical portion 73 via a bolt 89. In each of the tension rods 13, in a state where the extension 72 is moving in the axial direction, the friction between the cylindrical portion 73 and the extension 72 is reduced by the slide plates 87, 88.

[0055] As shown in FIG. 9 and the like, in each of the pair of stopper members 19, a longitudinal direction (the directions indicated by arrows C7 and C8), a height direction (the directions indicated by arrows Y7 and Y8) that intersects (is orthogonal or substantially orthogonal) to the longitudinal direction, and a width direction (the directions indicated by arrows W3 and W4) that intersects (is orthogonal or substantially orthogonal) to both the longitudinal direction and the height direction are defined. In FIGS. 10 to 12, the direction orthogonal or substantially orthogonal to the paper surface is the width direction of the stopper member 19. In each of the pair of tension units, the stopper member 19 is attached to the rear end portion of the tension rod 13 in a state where the width direction coincides or substantially coincides with the width direction of the jib 12.

[0056] Each of the pair of stopper members 19 is formed from a pair of plate members 91. In each of the stopper members 19, a gap is formed between the pair of plate members 91 in the width direction (the width direction of the jib 12). Also, as shown in FIGS. 9 to 12 and the like, each of the stopper members 19 includes a bar portion 92 and protruding piece portions 93, 95, and in each of the stopper members 19, the bar portion 92 and the protruding piece portions 93, 95 are formed from the pair of plate members 91. In each of the stopper members 19, the bar portion 92 extends along the longitudinal direction from the extending end E1 to the extending end E2. And in each of the pair of tension units, the stopper member 19 is attached to the protruding piece 86 of the cylindrical portion 73 of the tension rod 13 via a connecting pin 101. Also, in each of the stopper members 19, the end portion on the side where the extending end E1 is located in the bar portion 92 is attached to the corresponding one of the tension rods 13.

[0057] Also, in each of the stopper members 19, a connecting plate 96 that connects between the pair of plate members 91 is formed at an end portion of the bar portion 92 on the side where the extended end E2 is located, and the connecting plate 96 extends along the width direction. Further, in each bar portion 92 of the stopper member 19, although not shown in FIGS. 9 to 12 and the like, the space between the pair of plate members 91 is connected by a long plate (see FIG. 16). In each of the stopper members 19, the long plate extends along the longitudinal direction and is adjacent to the gap between the pair of plate members 91 from the side of the arrow Y8 in the height direction. And in each of the stopper members 19, the protruding pieces 93 and 95 are located between the connecting pin 101 and the connecting plate 96 in the longitudinal direction, and the protruding piece 93 is located closer to the connecting pin 101 than the protruding piece 95 in the longitudinal direction. Also, in each of the stopper members 19, the protruding piece 93 protrudes from the bar portion 92 toward one side (arrow Y7 side) in the height direction, and the protruding piece 95 protrudes from the bar portion 92 toward the side opposite to the protruding piece 93 (arrow Y8 side) in the height direction. In each of the stopper members 19, a pin hole 97 is formed in the protruding piece 93, and the pin hole 97 penetrates the protruding piece 93 along the width direction (the width direction of the jib 12). Also, in each of the stopper members 19, a pin hole 98 is formed in the protruding piece 95, and the pin hole 98 penetrates the protruding piece 95 along the width direction.

[0058] In each of the pair of tension units, the stopper member 19 is rotatable about the attachment position by the connecting pin 101 with respect to the tension rod 13. And in each of the tension units, the rotation axis of the stopper member 19 with respect to the tension rod 13 extends along the width direction of the jib 12. Also, each of the stopper members 19 is rotatable about the rotation axis (connecting pin 101) between the protruding state shown in FIGS. 11 and 12 and the like and the stored state shown in FIG. 10 and the like. Note that in each of the stopper members 19, the extended end E1 becomes the extended end on the side where the rotation axis is located in the longitudinal direction, and the extended end E2 becomes the extended end on the side opposite to the rotation axis in the longitudinal direction.

[0059] In each of the tension units, in the protruding state of the stopper member 19, the stopper member 19 extends rearwardly of the tension rod 13 from the rotation axis (connecting pin 101) of the stopper member 19 with respect to the rod body 71 of the tension rod 13 to the extending end E2. And in each of the tension units, in the protruding state of the stopper member 19, the stopper member 19 protrudes rearwardly from the rod body 71 (cylindrical portion 73) of the tension rod 13. Also, in each of the tension units, in the protruding stopper member 19, the bar portion 92 and the projecting piece portion 95 are located on the side opposite to the side where the jib 12 is located with respect to the long hole 78 etc. of the tension rod 13. And in each of the tension units, in the protruding stopper member 19, the projecting piece portion 93 projects from the bar portion 92 toward the side where the jib 12 is located, and the projecting piece portion 95 projects from the bar portion 92 toward the side opposite to the side where the jib 12 is located.

[0060] Also, in each of the tension units, in the protruding state of the stopper member 19, the pin hole 97 of the projecting piece portion 93 of the stopper member 19 overlaps with the pin hole (second pin hole) 85 of the cylindrical portion 73 of the tension rod 13. For this reason, in each of the tension units, in the protruding state of the stopper member 19, in addition to the pin hole 85 of the cylindrical portion 73 and the long hole 78 of the extension 72, the connecting pin 82 can be inserted into the pin hole 97 of the stopper member 19. And in each of the tension units, when the connecting pin 82 is inserted into the pin hole 85 of the cylindrical portion 73, the long hole 78 of the extension 72, and the pin hole 97 of the stopper member 19, the rotation about the rotation axis (connecting pin 101) of the stopper member 19 is restricted, and the stopper member 19 is maintained in the protruding state. Also, in each of the tension units, in the protruding state of the stopper member 19, the projecting piece portion 93 of the stopper member 19 sandwiches the cylindrical portion 73 of the rod body 71 and the extension 72 from both sides in the width direction of the jib 12.

[0061] In each of the tension units, in the stored state of the stopper member 19, the stopper member 19 extends forward from the rotation axis (connecting pin 101) of the stopper member 19 with respect to the rod body 71 of the tension rod 13 to the extending end E2. And in each of the tension units, in the stored state of the stopper member 19, the stopper member 19 does not protrude rearward from the rod body 71 (cylindrical portion 73) of the tension rod 13. Also, in each of the tension units, in the stopper member 19 in the stored state, the bar portion 92 and the protruding piece portion 93 are located on the side opposite to the side where the jib 12 is located with respect to the elongated hole 78 or the like of the tension rod 13. And in each of the tension units, in the stopper member 19 in the stored state, the protruding piece portion 95 protrudes from the bar portion 92 toward the side where the jib 12 is located, and the protruding piece portion 93 protrudes from the bar portion 92 toward the side opposite to the side where the jib 12 is located.

[0062] Also, in each of the tension units, in the stored state of the stopper member 19, the pin hole 98 of the protruding piece portion 95 of the stopper member 19 overlaps with the pin hole 83 of the cylindrical portion 73 of the tension rod 13. For this reason, in each of the tension units, in the stored state of the stopper member 19, in addition to the pin hole 83 of the cylindrical portion 73 and the elongated hole 78 of the extension 72 of the tension rod 13, the connecting pin 82 can be inserted into the pin hole 98 of the stopper member 19. And in each of the tension units, when the connecting pin 82 is inserted into the pin hole 83 of the cylindrical portion 73, the elongated hole 78 of the extension 72, and the pin hole 98 of the stopper member 19, the rotation about the rotation axis (connecting pin 101) of the stopper member 19 is restricted, and the stopper member 19 is maintained in the stored state. Also, in each of the tension units, in the stored state of the stopper member 19, the protruding piece portion 95 of the stopper member 19 sandwiches the cylindrical portion 73 of the rod body 71 and the extension 72 from both sides in the width direction of the jib 12.

[0063] Also, in each of the tension rods 13, a protruding piece portion 102 is formed at the rear end portion of the extension 72. In each of the tension rods 13, the protruding piece portion 102 forms the rear end, and the protruding piece portion 102 protrudes toward the side opposite to the side where the jib 12 is located. In each of the tension units, in the protruding state of the stopper member 19, the bar portion 92 of the stopper member 19 sandwiches the protruding piece portion 102 of the extension 72 from both sides in the width direction of the jib 12. At this time, in each of the tension units, the protruding piece portion 102 of the extension 72 is disposed in the gap between the pair of plate members 91 of the stopper member 19.

[0064] Also, in each of the tension units, when the connecting pin 82 is attached to the cylindrical portion 73 with the pin hole (second pin hole) 85 and the stopper member 19 is in the protruding state, corresponding to the movement along the axial direction of the extension 72, the protruding piece portion 102 of the extension 72 moves along the axial direction of the tension rod 13 in the gap between the pair of plate members 91 of the stopper member 19. At this time, in each of the tension units, the protruding piece portion 102 of the extension 72 moves while being sandwiched by the bar portion 92 of the stopper member 19 from both sides in the width direction of the jib 12.

[0065] FIGS. 13 and 14 show one of the pair of tension units. That is, in FIGS. 13 and 14, one of the pair of tension rods 13, one of the pair of boom side links 15, and one of the pair of stopper members 19 are shown. Here, FIG. 13 shows a state where the rod length of the tension rod 13 is the maximum rod length Lmax and the tension rod 13 is not bent with respect to the boom side link 15 to which it is connected. Further, FIG. 14 shows a state where the tension rod 13 is bent with respect to the boom side link 15 to which it is connected.

[0066] As shown in FIGS. 13 and 14 and the like, each of the pair of boom side links 15 is provided with a locking piece 103. In each of the boom side links 15, the locking piece 103 projects toward the side away from the front end face 25 of the boom. Further, in each of the pair of tension units, in a state where the tension rod 13 is not bent with respect to the connected boom side link 15, that is, in a state where it extends straight or substantially straight from the rear end of the boom side link 15 to the front end of the tension rod 13, the locking piece 103 of the boom side link 15 projects toward the side opposite to the side where the jib 12 is located.

[0067] Also, as shown in FIG. 13 and the like, in each of the tension units, when the rod length of the tension rod 13 becomes the maximum rod length Lmax and the tension rod 13 is not bent with respect to the connected boom side link 15, the projecting stopper member 19 abuts against the locking piece 103 of the boom side link 15 from the front side. At this time, in each of the tension units, the extending end E2 of the projecting stopper member 19 abuts against the locking piece 103 of the boom side link 15, and the stopper member 19 presses the locking piece 103 toward the rear side.

[0068] Therefore, in each of the tension units, in a state where the extension 72 of the tension rod 13 having the rod length of the maximum rod length Lmax is connected to the boom side link 15 and the stopper member 19 projects rearward from the rod body 71 (the projecting state of the stopper member 19), the stopper member 19 can abut against the boom side link 15 from the front side. Note that, in each of the tension units, the amount of projection of the stopper member 19 rearward from the cylindrical portion 73 (rod body 71) in the projecting stopper member 19 is the same as or substantially the same as the amount of projection of the extension 72 rearward from the cylindrical portion 73 in the tension rod 13 having the maximum rod length Lmax.

[0069] In each of the tension units, the protruding stopper member 19 abuts against the locking piece 103 of the boom side link 15 from the front side, and by the stopper member 19 pressing the locking piece 103 toward the rear side, a force that pulls the extension 72 of the tension rod 13 toward the rear side acts from the boom side link 15 on the extension 72. As a result, in each of the tension units, the movement of the extension 72 toward the front side is suppressed, and the contraction of the tension rod 13 from the maximum rod length Lmax is suppressed. Therefore, in each of the tension units, when the protruding stopper member 19 abuts against the boom side link 15 from the front side, the rod length of the tension rod 13 is maintained at the maximum rod length Lmax.

[0070] Also, as shown in FIG. 14 and the like, in each of the tension units, when the tension rod 13 is bent with respect to the connected boom side link 15, the protruding stopper member 19 does not abut against the locking piece 103 of the boom side link 15 from the rear side. That is, in each of the tension units, when the tension rod 13 is bent with respect to the boom side link 15, the above-described interference of the stopper member 19 with the locking piece 103 of the boom side link 15 does not occur. For this reason, in each of the tension units, when the tension rod 13 is bent with respect to the connected boom side link 15, the extension 72 can move along the axial direction of the tension rod 13, and the rod length of the tension rod 13 can vary within a range of not less than a predetermined rod length La and not more than the maximum rod length Lmax.

[0071] Next, the operation using the jib 12 will be described. When performing an operation using the jib 12 (when using the jib 12), the crane 1 is changed in the order of the states shown in FIGS. 1 and 7, the state shown in FIG. 2, the state shown in FIG. 3, the state shown in FIG. 4, the state shown in FIG. 5, and the state shown in FIG. 6 from the stored state. Also, when storing the jib 12 after using the jib 12, for example, starting from the state shown in FIG. 6, the crane 1 is changed in the order of the state shown in FIG. 5, the state shown in FIG. 4, the state shown in FIG. 3, the state shown in FIG. 2, and the states shown in FIGS. 1 and 7, and the jib 12 is stored from the states shown in FIGS. 1 and 7.

[0072] When the jib 12 is not in use, such as when the crane 1 is traveling, each of the jib-side couplings is connected to one corresponding boom-side coupling. For this reason, when the jib 12 is not in use, the jib 12 is stored on the boom lower surface 22 along the longitudinal direction of the boom 11. Therefore, the jib 12 can be arranged on the boom lower surface 22 along the longitudinal direction of the boom 11. In a state where the jib 12 is arranged on the boom lower surface 22, the jib lower surface 47 of the jib 12 faces the boom lower surface 22. And the jib 12 is arranged in a state where the front side (arrow C3 side) of the jib 12 coincides with or substantially coincides with the rear side (arrow C2) of the boom 11, and the rear side (arrow C4 side) of the jib 12 coincides with or substantially coincides with the front side (arrow C1 side) of the boom 11.

[0073] In a state where the boom 11 is arranged on the boom lower surface 22 by connecting the jib-side couplings to the boom-side couplings, by contracting the boom 11 to the most contracted state where the boom 11 is most contracted, each of the jib feet (jib-side engaging portions) 53 engages with the shafts (boom-side engaging portions) 37. Also, when the jib 12 is not in use, each of the jib hoisting cylinders 61 is in the most contracted state, and the slide bracket 60 is located at the rearmost position on the most rear side.

[0074] In addition, when the jib 12 is arranged along the longitudinal direction on the lower surface 22 of the boom, the tension rod 13 is arranged on the side opposite to the side where the boom 11 is located with respect to the jib 12. Further, when the jib 12 is not in use during traveling or the like, in each of the tension rods 13, the connecting pin 82 is attached to the cylindrical portion 73 of the rod body 71 by the pin hole 83. Therefore, when the jib 12 is not in use, in each of the tension rods 13, the movement of the extension 72 along the axial direction is restricted, and each of the tension rods 13 is stored in a state where the rod length is maintained at the minimum rod length Lmin. At this time, each of the tension rods 13 cannot be connected to the boom side link 15.

[0075] Further, when the jib 12 is not in use, each of the tension rods 13 engages with one corresponding to the rod receiver and is supported by one corresponding to the rod receiver. Further, when the jib 12 is not in use during traveling or the like, each of the boom side links 15 is stored in a state of engaging with one corresponding to the storage guide 65. Further, when the jib 12 is not in use, each of the stopper members 19 is in a stored state. Therefore, when the jib 12 is not in use, in each of the tension units, the connecting pin 82 inserted through the pin hole (first pin hole) 83 of the cylindrical portion 73 of the rod body 71 and the long hole 78 of the extension 72 is inserted through the pin hole 98 of the protruding piece portion 95 of the stopper member 19.

[0076] When performing work using the jib 12, as shown in FIG. 1, the outriggers 8A and 8B are grounded to the ground to stabilize the traveling vehicle body 2. Further, the boom 11 is placed in a state of being lowered to the fully lowered position or a position close to the fully lowered position. At this time, the boom 11 may be in a horizontal state or may form a depression angle with respect to the horizontal direction. Further, the boom 11 is brought into the most contracted state, and each of the jib feet 53 is engaged with the shaft 37. In this state, a foot pin 55 is attached to each of the jib feet 53, and the rear end portion (rear end) of the jib 12 is connected to the boom head 17 (front end portion of the boom 11).

[0077] Then, as shown in FIG. 7 and the like, in each of the pair of tension units, the connecting pin 82 is removed from the tension rod 13 and the stopper member 19. As a result, in each of the tension units, the extension 72 becomes movable along the axial direction of the tension rod 13, and the rod length of the tension rod 13 can be changed. Further, in each of the tension units, the stopper member 19 can rotate about the rotation axis (connecting pin 101). Then, each of the stopper members 19 is rotated from the stored state (the state of the broken line in FIG. 7) to the protruding state (the state of the solid line in FIG. 7), and each of the tension rods 13 is extended from the minimum rod length Lmin.

[0078] Then, in each of the tension units, the connecting pin 82 is inserted through the pin hole (second pin hole) 85 of the cylindrical portion 73 of the rod body 71, the long hole 78 of the extension 72, and the pin hole 97 of the protruding piece portion 93 of the stopper member 19. As a result, in each of the tension units, the connecting pin 82 is attached to the protruding stopper member 19, and the stopper member 19 is maintained in the protruding state. Further, in each of the tension rods 13, since the connecting pin 82 is attached to the cylindrical portion 73 at the pin hole 85, the rod length can be changed within the range of not less than the predetermined rod length La and not more than the maximum rod length Lmax.

[0079] Then, in each of the tension units, with the rod length of the tension rod 13 being changeable within the range of not less than the predetermined rod length La and not more than the maximum rod length Lmax, the extension 72 of the tension rod 13 is connected to the boom side link 15. At this time, each of the tension rods 13 is connected to the corresponding one of the boom side links 15 in a state where it is further extended from the predetermined rod length La. In one example, each of the tension rods 13 is connected to the corresponding one of the boom side links 15 in a state where the rod length becomes the maximum rod length Lmax. Then, when each of the corresponding tension rods 13 is connected to each of the boom side links 15, the engagement between each of the rod receivers of the tension rods 13 and the corresponding one is released, and the tension rod 13 is released.

[0080] After performing the foregoing operations, as shown in FIG. 2, the boom 11 is raised to the maximum raised position or a position close to the maximum raised position. Then, as shown in FIG. 3, the boom 11 is extended from the fully retracted state. At this time, the boom 11 is extended until the amount of extension from the fully retracted state becomes larger than a predetermined amount of extension. When the boom 11 is extended, the connection of each of the jib-side couplings to the corresponding one of the boom-side couplings is released. That is, the connection of the jib 12 to the boom 11 at a portion other than the connection position (shaft 37) to the boom head 17 is released. Then, the jib 12 is connected to the boom 11 only at the shaft 37 of the boom head 17 (front end portion of the boom 11), and becomes rotatable with respect to the boom 11 about the connection position (first position) to the boom head 17.

[0081] Further, since the connection to the boom-side coupling is released as described above, the jib 12 hangs down or substantially hangs down from the connection position to the boom head 17. In a state where the jib 12 hangs down or substantially hangs down, the longitudinal direction of the jib 12 coincides with or substantially coincides with the vertical direction, and the front side of the jib 12 coincides with or substantially coincides with the vertically lower side. Also, when the connection to the boom-side coupling is released and the jib 12 rotates until it hangs down or substantially hangs down, each of the tension rods 13 contracts. For example, in FIGS. 1 and 7 and the like, it is assumed that each of the tension rods 13 is connected to the corresponding one of the boom-side links 15 in a state where the rod length is the maximum rod length Lmax. In this case, between the state of FIG. 2 and the state where the jib 12 of FIG. 3 and the like hangs down or substantially hangs down, each of the tension rods 13 contracts, and in the state where the jib 12 of FIG. 3 and the like hangs down or substantially hangs down, the rod length of each of the tension rods 13 is shorter than the maximum rod length Lmax.

[0082] Then, as shown in FIG. 4, after lowering the boom 11 from the fully raised position or a position close to the fully raised position, the boom 11 is contracted to the fully retracted state. At this time, the boom 11 is lowered until the undulation angle becomes about 36°. In the process of changing from the state of FIG. 3 to the state of FIG. 4, each of the tension rods 13 is stretchable in the axial direction. Therefore, by lowering the boom 11 to the state of FIG. 4, the angle (offset angle) formed by the longitudinal direction of the jib 12 with respect to the longitudinal direction of the boom 11 changes. Therefore, even in the state of FIG. 4, the jib 12 is maintained in a state of hanging or substantially hanging from the boom head 17.

[0083] Also, by lowering the boom 11 to the state of FIG. 4, each of the tension rods 13 contracts. In one example, in the state of FIG. 4, the rod length of each of the tension rods 13 is a predetermined rod length La, that is, the minimum value of the rod length in a state where the connecting pin 82 is inserted into the pin hole (second pin hole) 85. Further, when the boom 11 is lowered to the state of FIG. 4, the auxiliary hook 45 is wound down to a state close to the ground by paying out the auxiliary winding rope. Then, the auxiliary winding rope is hung on the top sheave 63 at the front end of the jib 12.

[0084] Then, from the state of FIG. 4, each of the jib undulation cylinders 61 is extended until the extension amount from the fully retracted state becomes larger than a predetermined extension amount. As a result, the slide bracket 60 located at the rearmost position moves to the front side of the jib 12, and each of the tension rods 13 extends. After each of the jib undulation cylinders 61 is extended to a certain extent, as shown in FIG. 5, the boom 11 is raised to a certain extent. While the boom 11 is being raised to the state of FIG. 5, each of the tension rods 13 extends to the maximum rod length Lmax by raising the boom 11 to a predetermined undulation angle. Then, while the boom 11 is further raised from the aforementioned predetermined undulation angle to the state of FIG. 5, the rod length of each of the tension rods 13 is maintained at the maximum rod length Lmax.

[0085] When the boom 11 is in the raised state, until the tilting angle of the boom 11 reaches the aforementioned predetermined tilting angle, each of the tension rods 13 extends, so the angle formed by the longitudinal direction of the jib 12 with respect to the longitudinal direction of the boom 11 changes. For this reason, until the tilting angle of the boom 11 reaches the aforementioned predetermined tilting angle, the jib 12 is in a state of hanging or substantially hanging from the boom head 17. On the other hand, while the boom 11 is further raised from the aforementioned predetermined tilting angle to the state shown in FIG. 5, since each of the tension rods 13 is maintained at the maximum rod length Lmax, the angle formed by the longitudinal direction of the jib 12 with respect to the longitudinal direction of the boom 11 does not change. For this reason, by raising the boom 11 to the state shown in FIG. 5, the jib 12 changes from a state of hanging from the boom head 17 to a state of protruding forward of the boom 11.

[0086] Then, the boom 11 is further raised from the state shown in FIG. 5 until the boom 11 reaches the fully raised position or a position close to the fully raised position. As a result, the jib 12 further protrudes forward of the boom 11 with respect to the state shown in FIG. 5. And in a state where the boom is further raised from the state shown in FIG. 5, that is, in a state where the jib 12 protrudes forward of the boom 11 with respect to a state of hanging from the boom head 17, the jib tilting cylinder 61 is extended or contracted, and the slide bracket 60 is moved with respect to the base jib member 51. As a result, the jib 12 rotates with respect to the boom 11 about the connection position (shaft 37) to the boom head 17, and the jib 12 rises or falls with respect to the boom 11. At this time, when the jib tilting cylinder 61 is fully extended and the slide bracket 60 is positioned at the most forward position, the jib 12 reaches the state shown in FIG. 6 where it is most raised with respect to the boom 11.

[0087] Also, when the jib 12 rises with respect to the boom 11, each of the boom side links 15 rotates away from the boom head 17 about the connection position (shaft 36) to the boom head 17. As a result, the engagement of each of the storage guides 65 of the boom side links 15 with the corresponding one is released.

[0088] When the jib 12 is raised or lowered with respect to the boom 11 by the expansion and contraction of the jib hoisting cylinder 61, the rod length of each of the tension rods 13 is maintained at the maximum rod length Lmax. Further, by raising the jib 12 toward the state of FIG. 6, in each of the tension units, the bending angle of the tension rod 13 with respect to the boom side link 15 becomes smaller. And in the state where the jib 12 is raised to the most raised state, in each of the tension units, the tension rod 13 does not bend with respect to the boom side link 15, and each of the tension units extends straight or substantially straight from the rear end of the boom side link 15 to the front end of the tension rod 13. For this reason, in the state where the jib 12 is raised to the most raised position or a position close to the most raised position, in each of the tension units, the protruding stopper member 19 abuts on the locking piece 103 of the boom side link 15 from the front side.

[0089] Also, when the work using the jib 12 is completed, the jib 12 is stored. At this time, the jib 12 is stored by performing a procedure substantially reverse to the above-described procedure.

[0090] In the present embodiment, in each of the pair of tension rods 13, an extension 72 is attached to the rear end portion of the rod body 71, and the extension 72 is connected to one of the corresponding pair of boom side links 15. And in each of the pair of tension units, in a state where the stopper member 19 protrudes rearward from the rod body 71, the stopper member 19 sandwiches the protruding piece portion 102 of the extension 72 from both sides in the width direction of the jib 12. Here, each of the tension rods 13 is connected to one of the corresponding boom side links 15 in a state where the jib 12 is disposed on the boom lower surface 22 of the boom 11 as described above. At this time, by moving the extension 72 of each of the tension rods 13 rearward, each of the tension rods 13 is extended from the minimum rod length Lmin. And each of the extended tension rods 13 is connected to one of the corresponding boom side links 15.

[0091] In each of the tension units of the present embodiment, as described above, the stopper member 19 sandwiches the protruding piece portion 102 of the extension 72 from both sides in the width direction of the jib 12. Therefore, the play of the extension 72 in the width direction of the jib 12 is suppressed. As a result, it becomes easier to move each of the extensions 72 of the tension rods 13 along the axial direction, and it becomes easier to expand and contract each of the tension rods 13. Further, in each of the tension units, since the stopper member 19 sandwiches the protruding piece portion 102 of the extension 72 from both sides in the width direction of the jib 12, the downward deflection of the tension rod 13 connected to the boom side link 15 is effectively suppressed. As a result, in each of the tension units, interference between the tension rod 13 connected to the boom side link 15 and the traveling vehicle body 2 is effectively prevented. In the present embodiment, since each of the tension units is provided with the extension 72 and the stopper member 19 as described above, the work efficiency and safety are improved in the work of connecting each of the tension rods 13 to the corresponding one of the boom side links 15.

[0092] Further, in the present embodiment, each of the tension rods 13 is connected to the corresponding one of the boom side links 15 in a state where the rod length can be changed. Therefore, after connecting each of the tension rods 13 to the corresponding one of the boom side links 15, in the process of changing to a state where the jib 12 hangs or substantially hangs from the boom head 17 as in the state of FIG. 3 and the state of FIG. 4, each of the tension rods 13 contracts as described above. Therefore, in a state where the jib 12 hangs or substantially hangs from the boom head 17, the upward floating of each of the boom side links 15 is effectively suppressed, and the boom side link 15 is effectively prevented from being greatly separated from the front end surface 25 of the boom.

[0093] Further, in the present embodiment, as described above, in a state where the jib 12 hangs or substantially hangs from the boom head 17 in FIG. 4 or the like, after each of the jib hoisting cylinders 61 is extended to a certain extent, the boom 11 is raised to the fully raised position or a position close to the fully raised position. As a result, the jib 12 projects forward of the boom 11 with respect to the state of hanging from the boom head 17, and each of the tension rods 13 extends until it reaches the maximum rod length Lmax. Then, with the jib 12 projecting forward of the boom 11 with respect to the state of hanging from the boom head 17 and with the rod length of each of the tension rods 13 reaching the maximum rod length Lmax, each of the jib hoisting cylinders 61 is extended, causing the jib 12 to rise with respect to the boom 11. Therefore, in the present embodiment, in the state of FIG. 4 or the like, it is not necessary to regulate the expansion and contraction of each of the tension rods 13 by a fixing pin or the like, and it is not necessary to attach a fixing pin or the like to each of the tension rods 13. As a result, the working efficiency and safety during the use of the jib 12 are further improved.

[0094] In addition, since there is no need to perform the operation of attaching a fixing pin or the like to each of the tension rods 13, the slide bracket 60 can be arranged at a position away from the slewing platform 5 to the front side of the slewing body 3 during the traveling of the crane 1 in which the jib 12 is arranged on the lower surface 22 of the boom. By arranging the slide bracket 60 at a position away from the slewing platform 5 to the front side of the slewing body 3, interference of the slide bracket 60 with the slewing platform 5 during the traveling of the crane 1 or the like is effectively prevented. In particular, in the crane 1 or the like in which the hoisting angle of the boom 11 in the fully lowered position is a depression angle, interference of the slide bracket 60 with the slewing platform 5 during traveling is effectively prevented.

[0095] Also, in the state shown in FIG. 6 where the jib 12 is raised to the fully raised position or a position close to the fully raised position, in each of the tension units, the tension rod 13 does not bend with respect to the boom side link 15, and the protruding stopper member 19 abuts against the locking piece 103 of the boom side link 15 from the front side. For this reason, in the state shown in FIG. 6 where the jib 12 is raised to the fully raised position or a position close to the fully raised position, even if a load or the like acts on the side that raises the jib 12, in each of the tension rods 13, the movement of the extension 72 toward the front side is suppressed, and the contraction from the maximum rod length Lmax is suppressed. As a result, in the state where the jib 12 is raised to the fully raised position or a position close to the fully raised position, the fall or the like of the jib 12 to the rear side of the slewing body 3 is effectively prevented. Therefore, the safety during the use of the jib 12 is further improved. Further, in each of the tension units of the present embodiment, since the stopper member 19 sandwiches the protruding piece portion 102 of the extension 72 from both sides in the width direction of the jib 12, the play of the stopper member 19 in the width direction of the jib 12 is suppressed. As a result, in each of the tension units, the stopper member 19 is suppressed from shifting in the width direction of the jib 12 with respect to the extension 72, and the stopper member 19 reliably abuts against the locking piece 103 of the boom side link 15.

[0096] Also, in each of the tension rods 13, the extension 72 is attached to the rod body 71 while being inserted into the internal space of the cylindrical portion 73. For this reason, in each of the tension rods 13, it becomes possible for the cylindrical portion 73 (for example, the connecting plate 76) to receive a force or the like that bends the rod body 71 with respect to the extension 72, and the bending of the rod body 71 with respect to the extension 72 is effectively suppressed. In each of the tension rods 13, since the bending of the rod body 71 with respect to the extension 72 is suppressed, contact with the traveling vehicle body 2 is effectively prevented. Also, in each of the tension rods 13, in a state where the extension 72 is moving in the axial direction, the friction between the cylindrical portion 73 and the extension 72 is reduced by the slide plates 87, 88. Therefore, in the operation of connecting each of the tension rods 13 to the corresponding one of the boom side links 15, the work efficiency and safety are further improved.

[0097] Also, in each of the tension rods 13 of the present embodiment, in a state where the rod length is the minimum rod length Lmin, the pin hole (second pin hole) 85 of the cylindrical portion 73 is displaced rearward with respect to the long hole 78 of the extension 72. Also, in each of the tension rods 13, in a state extended from the minimum rod length Lmin, the pin hole (first pin hole) 83 of the cylindrical portion 73 is displaced forward with respect to the long hole 78 of the extension 72. For this reason, in each of the tension units, it is effectively prevented that the connecting pin 82 is attached to the cylindrical portion 73 at an inappropriate position, such as when the jib 12 is used.

[0098] As described above, in the present embodiment, the work efficiency and safety are improved when the jib 12 is used, including operations such as connecting the tension rod 13 to the boom side link 15.

[0099] (Modification example) In the first modification example shown in Fig. 15 and the like, the slide plates 87 and 88 are not provided. In each of the tension rods 13, a pair of rollers 111 and a pair of rollers 112 are attached to the cylindrical portion 73 of the rod body 71. In each of the tension rods 13, each of the rollers 111 and 112 is rotatable about a rotation axis along the width direction of the jib 12, and the extension 72 is movable axially with respect to the rod body 71 and the rollers 111 and 112. In each of the tension rods 13 of this modification example, in a state where the extension 72 is moving axially, the friction acting on the extension 72 is reduced by the rollers 111 and 112.

[0100] Also, in each of the tension rods 13 of this modification example, the side plate 75 of the cylindrical portion 73 can receive a force or the like for bending the rod body 71 with respect to the extension 72 via the rollers 111 and 112. For this reason, in each of the cylindrical portions 73 of the tension rod 13, the range in which the connecting plate 76 extends axially can be reduced. In an example of Fig. 15, in each of the cylindrical portions 73 of the tension rod 13, an opening through which the internal space opens to the side where the jib 12 is located (arrow Y6 side), and an opening through which the internal space opens to the side opposite to the side where the jib 12 is located (arrow Y5 side) are formed. And in each of the cylindrical portions 73 of the tension rod 13, each of the openings is formed in a long hole shape along the axial direction. In each of the tension rods 13, weight reduction can be achieved by reducing the range in which the connecting plate 76 is formed.

[0101] In the second modification example shown in Fig. 16, a storage bracket 105 is attached to each of the jib feet 53 of the jib 12. Each of the storage brackets 105 is disposed on the jib upper surface 46. Also, in each of the tension rods 13, a plate 106 is fixed to the extension 72. In each of the tension rods 13, the plate 106 moves with the extension 72 with respect to the rod body 71. Note that the storage bracket 105 and the plate 106 are also shown in Fig. 8.

[0102] When the jib 12 is stored in the boom lower surface 22, each plate 106 of the tension rod 13 is inserted from the rear side of the jib 12 into the corresponding one of the storage brackets 105 of the jib foot 53 and stored inside the corresponding one of the storage brackets 105 of the jib foot 53. And for each of the tension rods 13, in a state where the plate 106 is stored in the corresponding one of the storage brackets 105 of the jib foot 53, the connecting pin 82 is attached to the cylindrical portion 73 through the pin hole (first pin hole) 83. Thereby, it is effectively prevented that the plate 106 comes out from the corresponding one of the storage brackets 105 of the jib foot 53.

[0103] Also, each of the tension rods 13 abuts against the contact portion 107 of the jib upper surface 46 of the jib 12 from the vertically lower side when the plate 106 is stored in the storage bracket 105. Thereby, for each of the tension rods 13, the portion on the rear side from the contact position to the contact portion 107 deflects upward vertically (arrow A1). And for each of the tension rods 13, with the portion on the rear side from the contact position being deflected, the plate 106 is inserted into the corresponding storage bracket 105 from the rear side (arrow A2). Incidentally, in one example, each contact portion 107 of the tension rod 13 is located between the jib foot 53 and the jib hoisting cylinder 61 in the longitudinal direction of the jib 12 (see FIG. 1).

[0104] As described above, in this modification example, each of the tension rods 13 can be stored with a simple configuration. Also, for each of the tension rods 13, the plate 106 is inserted into the corresponding storage bracket 105 with the portion on the rear side from the contact position to the contact portion 107 being deflected. For this reason, it is effectively prevented that each of the tension rods 13 vibrates due to vibrations during traveling or the like.

[0105] Note that the invention of the present application is not limited to the above embodiments, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, each embodiment may be implemented by appropriately combining them as much as possible, and in that case, the combined effects can be obtained. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of a plurality of disclosed constituent elements.

Explanation of Signs

[0106] 1... Crane, 2... Traveling vehicle body, 3... Slewing body, 5... Slewing base, 11... Boom, 12... Jib, 13... Tension rod, 15... Boom side link, 19... Stopper member, 22... Lower surface of boom, 36... Shaft (shaft for guide sheave), 37... Shaft (shaft for top sheave), 60... Slide bracket, 61... Jib hoisting cylinder, 71... Rod body, 72... Extension, 73... Cylindrical portion, 82... Connecting pin, 83... Pin hole (first pin hole), 85... Pin hole (second pin hole).

Claims

1. A boom that can be undulated and is stretchable in the longitudinal direction, the boom having a lower boom surface facing the side to be lowered, A jib that can be arranged along the longitudinal direction of the boom on the lower boom surface of the boom and can be connected to the front end of the boom at a first position, the jib being rotatable with respect to the boom about the first position, A boom side link connected to the front end of the boom at a second position located on the side where the boom rises with respect to the first position, A rod body having a front end connected to the jib, and an extension attached to the rear end of the rod body and connectable to the boom side link. A tension rod in which the rod length along the axial direction changes in response to the movement of the extension along the axial direction with respect to the rod body, A stopper member that can be attached to the rear end of the rod body in a state of protruding rearward from the rod body, and in a state of protruding rearward from the rod body, sandwiches the extension from both sides in the width direction of the jib that intersects both the axial direction of the tension rod and the undulation direction of the jib, A construction machine comprising the above.

2. The stopper member is attached to the rod body so as to be rotatable between a protruding state and a retracted state about a rotation axis along the width direction of the jib, In the protruding state, the stopper member extends rearward from the rotation axis to an extended end on the side opposite to the rotation axis, and protrudes rearward from the rod body, In the retracted state, the stopper member extends forward from the rotation axis to the extended end on the side opposite to the rotation axis, The construction machine according to Claim 1.

3. The extension of the tension rod, where the rod length is the maximum rod length, is connected to the boom side link, and in a state where the stopper member protrudes rearward from the rod body, the stopper member can contact the boom side link from the front side. By contacting the boom side link from the front side, the stopper member maintains the rod length of the tension rod at the maximum rod length. The construction machine according to claim 1 or 2.

4. Further comprising a connecting pin that can be attached to the rear end of the rod body at each of the first pin hole and the second pin hole formed on the rear side with respect to the first pin hole. In a state where the connecting pin is attached to the rod body at the first pin hole, the movement of the extension with respect to the rod body along the axial direction of the tension rod is restricted, and the rod length of the tension rod is maintained at the minimum rod length. In a state where the connecting pin is attached to the rod body at the second pin hole, the extension can move with respect to the rod body along the axial direction of the tension rod, and the rod length of the tension rod can change between a predetermined rod length that is longer than the minimum rod length and shorter than the maximum rod length and the maximum rod length. The construction machine according to any one of claims 1 to 3.

5. Further comprising a jib hoisting cylinder attached to the jib in a telescopic state. By extending or contracting the jib hoisting cylinder, the connection position of the front end of the rod body to the jib changes. When the connection position of the front end of the rod body to the jib changes in a state where the rod length of the tension rod is the maximum rod length, the jib can be hoisted with respect to the boom. The construction machine according to any one of claims 1 to 4.

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