JP3216179U - Boom device - Google Patents

Abstract

A boom device including a boom capable of quickly performing jib work is provided. A boom device includes a top boom, an intermediate boom, and a base boom that form a telescopic structure. The top boom 21 rotatably connects a plurality of arm bodies 71 arranged along the longitudinal direction 101 and two adjacent arm bodies 71 via a predetermined rotation shaft, and the arm body 71 on the distal end side is connected. Is allowed to displace between the first posture arranged along the longitudinal direction 101 with respect to the arm body 71 on the rear end side and the second posture rotated downward from the first posture by its own weight. A hinge mechanism 72 is provided. [Selection] Figure 1

Description

  The present invention relates to a boom device having an extendable boom.

  As an example of a thing provided with said boom apparatus, the crane provided with the jib in addition to the boom which can be raised and retracted is well-known (for example, refer patent document 1). The jib is detachable from the tip of the boom. As shown in this document, the jib is attached to the tip of the boom as necessary, and realizes a high lift work and a wide work radius that are impossible with the boom alone. For example, in the work of lowering a hanging hook on the roof of a building, a jib is attached to the tip of the boom. Thereby, the hook for suspended loads can be sent into the back | inner part of a rooftop, without making the height of the front-end | tip part of a boom more than necessary with respect to the said building (jib work).

JP 2006-222373 A

  The operation of attaching the jib to the boom is generally a manual operation by an operator. The boom is once laid down to the vicinity of the ground, and the operator connects the jib to the boom. In some cases, the hydraulic actuator supports the jib attachment work, but in any case, the jib attachment work takes time and effort, and the jib work cannot be performed quickly.

  The present invention has been made based on such a background, and an object of the present invention is to provide a boom apparatus including a boom that can quickly perform a jib operation.

  (1) A boom device according to the present invention is equipped with a plurality of booms constituting a telescopic. At least one of the plurality of booms includes a plurality of arm bodies arranged along the longitudinal direction of the boom and two adjacent arm bodies rotatably connected via a predetermined rotation shaft, The side arm body is displaced between a first posture in which the arm body on the side is arranged along the longitudinal direction with respect to the arm body on the rear end side, and a second posture rotated downward from the first posture by its own weight. A hinge mechanism that allows

  According to this configuration, when a boom including a plurality of arm bodies and a hinge mechanism is extended, each arm body except the most proximal arm body rotates to the second posture by its own weight. Thereby, the tip of the boom can be positioned further forward.

  (2) The boom device according to the present invention is equipped with a plurality of booms constituting a telescopic. At least one of the plurality of booms includes two arm bodies arranged along the longitudinal direction of the boom, the two arm bodies are connected via a predetermined rotation shaft, and the arm body on the front end side is the rear side. A hinge mechanism that allows displacement between a first posture disposed along the longitudinal direction with respect to the arm body on the end side and a second posture rotated downward from the first posture; and An actuator for displacing the arm body on the distal end side in the first posture and the second posture.

  According to this configuration, when the boom including the two arm bodies and the hinge mechanism is extended, the distal end side arm body is rotated to the second posture by the actuator, so that the tip of the boom is moved forward. Can be positioned.

  (3) The hinge mechanism is provided on the base end side of the boom.

  According to this configuration, the arm body on the distal end side can be sent forward with a small amount of rotation.

  According to this device, the jib work can be performed quickly.

FIG. 1 is a side view of a work vehicle 11 employing a crane 10 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the boom device 14 and shows a state in which each boom is extended. FIG. 3 is a cross-sectional view schematically showing the boom device 14 and shows a state in which each boom is contracted. FIG. 4 is a side view schematically showing the top boom 21 in which each arm body 71 is in the second posture. FIG. 5 is a side view schematically showing the top boom 21 in which each arm body 71 is in the first posture. FIG. 6 is a cross-sectional view schematically showing a boom device 14 in a modification of the first embodiment, and shows a state in which each boom is extended. FIG. 7 is a side view schematically showing the top boom 21 in which the arm body 91A is in the second posture in the second embodiment. FIG. 8 is a side view schematically showing the top boom 21 in which the arm body 91A is in the first posture in the second embodiment.

[Embodiment 1]

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, this Embodiment is only one aspect | mode of the crane provided with the boom apparatus which concerns on this invention, and it cannot be overemphasized that an embodiment may be changed in the range which does not change the summary of this invention.

  FIG. 1 is a side view of a work vehicle 11 employing a crane 10 according to an embodiment of the present invention. FIG. 1 schematically shows the work vehicle 11 and the crane 10.

[Work vehicle]

  As shown in FIG. 1, the work vehicle 11 is typically a crane vehicle. In the present embodiment, the work vehicle 11 includes a self-propelled device including a traveling engine and a steering mechanism, an actuator driving device including a hydraulic pump, and a grounding safety device including an outrigger device 15.

[crane]

  As shown in FIG. 1, the crane 10 includes a swivel base 13 and a boom device 14. The turntable 13 is mounted on the work vehicle 11 and can turn with respect to the work vehicle 11 via a turning actuator (not shown).

  The boom device 14 is telescopic in the longitudinal direction 101 as will be described later, and is connected to the swivel base 13 via the hoisting cylinder 18 in a hoistable state. A suspension load winch 16 is provided on the swivel base 13. The suspended load winch 16 includes a drum (not shown) and a suspended wire 17 having a required length. The suspended wire 17 is wound around the drum and held. The suspended wire 17 drawn from the drum is wound around a suspended wire sheave 26 provided in the boom device 14 and is suspended. A hook 29 is provided at the tip of the hanging wire 17. When the suspended winch 16 is actuated while the suspended load 30 is suspended from the hook 29, the drum is driven and the suspended wire 17 is unwound from the drum or wound up, so-called a suspended load operation is performed.

[Swivel stand]

  As shown in FIG. 1, the swivel base 13 is connected to the work vehicle 11 via the turning actuator (typically a turntable and a hydraulic motor). Although not shown, the actuator driving device is arranged on the swivel base 13, and a counterweight or the like can be mounted.

[Boom device]

  As shown in FIGS. 1 and 2, the boom device 14 includes a telescopic structure, and includes a boom body 25 and a telescopic cylinder 50 that expands and contracts the boom main body 25. The boom body 25 includes a plurality of booms, that is, a top boom 21, an intermediate boom 22, and a base boom 23. These are formed of cylindrical members having a so-called closed cross section, and are assembled in a so-called nested manner as shown in FIGS. As shown in FIG. 3, the intermediate boom 22 is inserted and accommodated in the accommodation space 23 </ b> A of the base boom 23, and the top boom 21 is inserted and accommodated in the accommodation space 22 </ b> A of the intermediate boom 22. The intermediate boom 22 is slidable in the longitudinal direction 101 with respect to the base boom 23, and this relationship is similarly established between the intermediate boom 22 and the top boom 21.

  As shown in FIG. 1, the base end portion of the base boom 23 is connected to the swivel base 13. A base end portion of the base boom 23 is rotatably supported by the swivel base 13 via a undulation center pin (not shown). The hoisting cylinder 18 is interposed between the swivel base 13 and the base boom 23 as shown in FIG. When the hoisting cylinder 18 expands and contracts, the base boom 23 and, consequently, the boom body 25 moves up and down.

  As shown in FIGS. 2 and 3, the boom device 14 has a telescopic cylinder 50 built therein. The telescopic cylinder 50 includes a base rod 51 and an intermediate rod 52. The base rod 51 is disposed in the accommodation space 23 </ b> A and is fixed to the base boom 23. The intermediate rod 52 is disposed in the accommodation space 22 </ b> A and is fixed to the intermediate boom 22. The intermediate rod 52 can be expanded and contracted with respect to the base rod 51. By operating the telescopic cylinder 50 so that the intermediate rod 52 extends and contracts with respect to the base rod 51, the intermediate boom 22 slides relative to the base boom 23. As a result, the length of the boom device 14 changes. To do.

  In addition, the boom device 14 includes a rope expansion / contraction mechanism 60. The rope expansion / contraction mechanism 60 includes an extension sheave 61, an extension wire rope 62, a contraction sheave 63, and a contraction wire rope 64. The extension sheave 61 is provided at the tip of the intermediate boom 22. The extension wire rope 62 is stretched over the extension sheave 61. One end of the wire rope 62 for extension is attached to a fixed portion 62A provided at the tip of the base boom 23. The other end of the wire rope 62 for extension is attached to a fixed portion 62 </ b> B provided at the base end portion of the top boom 21. The configuration of the contraction sheave 63 and the contraction wire rope 64 is also substantially the same as that of the extension sheave 61 and the extension wire rope 62, and the contraction wire rope 64 is stretched over the contraction sheave 63, and the contraction wire rope One end and the other end of 64 are fixed to the fixing portions 64A and 64B, respectively. However, the shrinking sheave 63 is provided at the proximal end portion of the intermediate boom 22.

  When the intermediate boom 22 extends with respect to the base boom 23, the extension wire rope 62 is pulled, and the top boom 21 extends with respect to the intermediate boom 22 (see FIG. 2). When the intermediate boom 22 contracts with respect to the base boom 23, the contracting wire rope 64 is pulled, and the top boom 21 contracts with respect to the intermediate boom 22, and is accommodated in the intermediate boom 22 (see FIG. 3).

  A curved surface 24 is formed on the intermediate boom 22. The curved surface 24 is formed at the tip of the intermediate boom 22 in the surface 22B that defines the lower side of the accommodation space 22A of the intermediate boom 22. The curved surface 24 is curved so as to go downward as it goes to the distal end side.

[Arm body and hinge mechanism]

  As shown in FIGS. 1 and 4, the top boom 21 includes five arm bodies 71 and four hinge mechanisms 72. The number of arm bodies 71 is not limited to five, and the number of hinge mechanisms 72 is not limited to four.

  As shown in FIGS. 4 and 5, the five arm bodies 71 are arranged along the longitudinal direction 101. As shown in FIGS. 2 and 3, each arm body 71 is configured in a cylindrical shape. As shown in FIG. 3, in the state where the top boom 21 is accommodated in the intermediate boom 22, the intermediate rod 52 of the telescopic cylinder 50 passes through the internal space of each arm body 71.

  In the state where the top boom 21 is accommodated in the intermediate boom 22, the intermediate rod 52 and the top boom 21 may be disposed at different positions in the accommodation space 22A. In this case, the intermediate rod 52 does not pass through the internal space of each arm body 71 in this state. Therefore, in this case, each arm body 71 does not necessarily need to be configured in a cylindrical shape.

  As shown in FIGS. 2 and 4, each arm body 71 includes four side plates 73, 74, 75, 76. The side plates 73 and 74 are opposed to each other in the width direction. The width direction is a direction perpendicular to the paper surface in each figure. The side plate 75 connects the upper end of the side plate 73 and the upper end of the side plate 74, and the side plate 76 connects the lower end of the side plate 73 and the lower end of the side plate 74.

  As shown in FIG. 4 and FIG. 5, the hinge mechanism 72 connects two adjacent arm bodies 71. The hinge mechanism 72 includes a through hole 82, a long through hole 79, a first convex part 77, and a second convex part 78 formed in the side plates 73 and 74 of each arm body 71.

  The through hole 82 is formed in the lower end portion of the base end portion of the side plates 73 and 74. The long through hole 79 is formed above the through hole 82 in the base end portion of the side plates 73 and 74. The long through-hole 79 extends while being inclined with respect to the longitudinal direction 101 so as to be directed downward toward the tip of the arm body 71.

  The first convex portion 77 protrudes in the longitudinal direction 101 from the lower end portion at the tip of the side plates 73 and 74. A first protrusion 80 protruding in the width direction is provided at the protruding tip of the first convex portion 77. The first protrusion 80 provided on the predetermined arm body 71 is inserted into a through hole 82 formed in the arm body 71 adjacent to the predetermined arm body 71 on the distal end side in the longitudinal direction 101. For example, the first protrusion 80 provided on the arm body 71A is inserted through a through hole 82 formed in the arm body 71B. The same applies to the other two adjacent arm bodies 71. As described above, the arm body 71 moves the other arm body 71 adjacent to the distal end side from the arrow 102 (FIG. 4) around the rotation axis that is an axis passing through the center 80C of the first protrusion 80 and extending in the width direction. Reference) and an arrow 103 (see FIG. 5).

  The second convex part 78 projects in the longitudinal direction 101 from above the first convex part 77 at the tips of the side plates 73 and 74. A second protrusion 81 protruding in the width direction is provided at the protruding tip of the second protrusion 78. The second protrusion 81 provided on the predetermined arm body 71 is inserted into a long through hole 79 formed in the arm body 71 adjacent to the predetermined arm body 71 on the distal end side. For example, the second protrusion 81 provided on the arm body 71A is inserted through a long through hole 79 formed on the arm body 71B. Thereby, the rotation range of the arm body 71 is limited to a predetermined range. Here, the predetermined range is a range between the first posture shown in FIG. 5, the second posture shown in FIG. 4, and between the first posture and the second posture.

  As shown in FIG. 5, the arm body 71 is disposed along the longitudinal direction 101 with respect to the arm body 71 adjacent to the rear end side in the first posture. As shown in FIG. 4, when the arm body 71 is in the second posture, the tip of the arm body 71 is rotated downward by its own weight as compared with the first posture.

  As described above, when the first protrusion 80 is inserted into the through hole 82 and the second protrusion 81 is inserted into the long through hole 79, the two adjacent arm bodies 71 rotate around the rotation shaft. It is connected movably and is displaced between the first posture and the second posture.

[Operation of each arm body when the top boom is extended and retracted]

  Hereinafter, the operation of each arm body 71 when the top boom 21 extends and contracts with respect to the intermediate boom 22 will be described.

  As shown in FIGS. 3 and 5, in a state where the top boom 21 is accommodated in the accommodating space 22 </ b> A of the intermediate boom 22, each arm body 71 is supported by the surface 22 </ b> B of the intermediate boom 22, and the longitudinal direction 101. Are lined up in a row. Each arm body 71 at this time is in the first posture. When the arm body 71 is in the first posture, the second protrusion 81 is located on the distal end side of the long through hole 79.

  When the top boom 21 starts to extend with respect to the intermediate boom 22, first, the arm body 71 located on the most distal side among the five arm bodies 71 protrudes from the intermediate boom 22. The arm body 71 protruding from the intermediate boom 22 rotates in the direction of the arrow 103 (see FIG. 5) by its own weight. By this rotation, the tip of the arm body 71 moves downward. Further, by the rotation, the second protrusion 81 slides relative to the long through hole 79 from the distal end side to the proximal end side of the long through hole 79. As shown in FIG. 4, the slid second protrusion 81 comes into contact with the base end surface 79 </ b> A that defines the base end of the long through hole 79. Thereby, the rotation of the arm body 71 in the direction of the arrow 103 (see FIG. 5) is restricted. At this time, the arm body 71 is in the second posture. That is, the long through hole 79 restricts the rotation of the arm body 71 in the direction of the arrow 103 in the second posture.

  Hereinafter, as the top boom 21 extends with respect to the intermediate boom 22, the remaining three arm bodies 71 also rotate in the direction of the arrow 103 in the same manner as described above. Of the five arm bodies 71, the arm body 71 located on the most proximal side does not rotate. Finally, as shown in FIGS. 2 and 4, in all four rotatable arm bodies 71, the second protrusion 81 of the adjacent arm body 71 abuts on the base end surface 79 </ b> A of the long through hole 79. It becomes a state. That is, all of the four arm bodies 71 are in the second posture. As described above, the arm body 71 rotates from the first posture to the second posture by its own weight in a state where it is not supported by the intermediate boom 22 which is another member.

  When the top boom 21 starts to contract with respect to the intermediate boom 22 in the state shown in FIGS. 2 and 4, the arm boom 71 is sequentially inserted into the intermediate boom 22 from the base end side and is stored in the storage space 22 </ b> A ( 3 and 5). In the insertion process, the side plate 76 of each arm body 71 is guided toward the accommodation space 22A along the curved surface 24 (see FIGS. 2 and 3) of the intermediate boom 22. Each arm body 71 is rotated in the direction of the arrow 102 (see FIG. 4) so as to be lifted by the curved surface 24, and assumes the first posture. That is, when the top boom 21 is slid and accommodated with respect to the intermediate boom 22, the curved surface 24 abuts on each arm body 71 and corrects each arm body 71 from the second posture to the first posture. Further, by the rotation, the second protrusion 81 slides relative to the long through hole 79 from the proximal end side to the distal end side of the long through hole 79. As shown in FIGS. 3 and 5, the five arm bodies 71 are arranged along the longitudinal direction 101 in a state where the top boom 21 is completely accommodated in the intermediate boom 22. That is, in this state, the five arm bodies 71 are located in the first posture.

[Effects of Embodiment 1]

  According to the first embodiment, when the top boom 21 including the plurality of arm bodies 71 and the hinge mechanism 72 is extended, each arm body 71 excluding the most proximal arm body 71 moves to the second posture by its own weight. Rotate. Thereby, the front-end | tip of the top boom 21 can be located more forward.

  According to the first embodiment, when the top boom 21 is accommodated in the intermediate boom 22, the arm body 71 rotating to the second posture by its own weight contacts the curved surface 24 and takes the first posture. It will be corrected. Therefore, the top boom 21 can be smoothly accommodated in the intermediate boom 22 along the curved surface 24.

[Modification of Embodiment 1]
In the first embodiment, the intermediate boom 22 includes the curved surface 24 at the distal end portion in the longitudinal direction 101 of the surface 22B that contacts when the top boom 21 is accommodated. However, the intermediate boom 22 is not limited to the curved surface 24 that is provided at the tip portion. For example, instead of the curved surface 24, the intermediate boom 22 may include an inclined surface that is a plane that faces downward as it goes toward the distal end side in the longitudinal direction 101.

  For example, as shown in FIG. 6, the intermediate boom 22 may include a roller member 27 that is rotatably supported by the tip portion. A part of the roller is located above and on the tip side of the surface 22B. In the process in which the top boom 21 is inserted into the intermediate boom 22, the side plate 76 of the arm body 71 contacts the roller member 27. The roller member 27 in contact with the arm body 71 rotates and guides the arm body 71 toward the accommodation space 22A.

  According to this modified example, when the top boom 21 is accommodated in the intermediate boom 22, each arm body 71 rotating to the second posture abuts on the roller member 27. The roller member 27 in contact with each arm body 71 rotates. Thereby, the top boom 21 can be smoothly accommodated in the intermediate boom 22.

[Embodiment 2]

  In the above embodiment, the arm body 71 protruding from the intermediate boom 22 is rotated in the direction of the arrow 103 (see FIG. 5) by its own weight, so that the first posture shown in FIGS. It shifted to the 2nd attitude | position which 4 shows. However, the arm body 71 may be rotated not by its own weight but by applying a driving force from the actuator.

  For example, as illustrated in FIGS. 7 and 8, the top boom 21 may include two arm bodies 91, a hinge mechanism 92 that couples the two arm bodies 91, and a hydraulic cylinder 96.

  The configuration of the two arm bodies 91 is substantially the same as that of the arm body 71 of the above embodiment. However, the arm body 91A located on the distal end side of the two arm bodies 91 is longer in the longitudinal direction 101 than the arm body 91B located on the proximal end side of the two arm bodies 91. In the configuration shown in FIGS. 7 and 8, the length of the arm body 91A in the longitudinal direction 101 is substantially the same as the total length of the four arm bodies 71 in the longitudinal direction 101 in the embodiment described above. The length in the longitudinal direction 101 is substantially the same as the length in the longitudinal direction 101 of one arm body 71 in the above embodiment.

  The hinge mechanism 92 is provided at the boundary between the arm body 91A and the arm body 91B. Here, since the arm body 91 </ b> A on the distal end side in the longitudinal direction 101 is longer than the arm body 91 </ b> B on the proximal end side, the boundary portion is located on the proximal end side of the top boom 21. That is, the hinge mechanism 92 is located on the proximal end side of the top boom 21.

  The hinge mechanism 92 includes a through hole 93 and a convex portion 94 having a protrusion 95. The through hole 93 corresponds to the through hole 82 in the above embodiment and has the same configuration as the through hole 82. The convex portion 94 corresponds to the first convex portion 77 in the above embodiment, and has the same configuration as the first convex portion 77. The protrusion 95 corresponds to the first protrusion 80 in the above embodiment and has the same configuration as the first protrusion 80. By the hinge mechanism 92, the arm body 91B causes the arm body 91A to pass through the center of the protrusion 95 and center on a rotation shaft 95C that is an axis extending in the width direction, and the first posture shown in FIG. The second posture is supported so as to be rotatable along arrows 104 (see FIG. 8) and arrows 105 (see FIG. 7).

  As shown in FIG. 8, the arm body 91A is disposed along the longitudinal direction 101 with respect to the arm body 91B when in the first posture. As shown in FIG. 7, the arm body 91 </ b> A is bent with respect to the arm body 91 </ b> A when in the second posture, and its tip is rotated downward as compared with when it is in the first posture.

  As shown in FIGS. 7 and 8, the hydraulic cylinder 96 is attached above the hinge mechanism 92 so as to connect the arm body 91A and the arm body 91B. The hydraulic cylinder 96 displaces the arm body 91A between the first posture and the second posture. As the hydraulic cylinder 96 extends, the arm body 91A rotates from the first posture in the direction of the arrow 104 (see FIG. 8) and is displaced to the second posture (see FIG. 7). When the hydraulic cylinder 96 contracts, the arm body 91A rotates from the second posture in the direction of the arrow 105 (see FIG. 7) and is displaced to the first posture (see FIG. 8).

  According to the second embodiment, when the top boom 21 including the two arm bodies 91A and 91B and the hinge mechanism 92 is extended, the distal end side arm body 91A is rotated to the second posture by the hydraulic cylinder 96. Thus, the tip of the top boom 21 can be positioned further forward.

  Further, according to the second embodiment, since the hinge mechanism 92 is provided on the proximal end side of the top boom 21, the distal end side arm body 91A can be sent forward with a small amount of rotation.

[Modification of Embodiment 2]

  The length relationship in the longitudinal direction 101 between the arm body 91A and the arm body 91B is not limited to that shown in FIGS. For example, the arm body 91A and the arm body 91B may have the same length in the longitudinal direction 101. Further, the position of the hinge mechanism 92 varies depending on the length relationship between the arm bodies 91A and 91B. That is, the position of the hinge mechanism 92 is not limited to the proximal end side of the top boom 21.

  The means for applying a driving force for rotating the arm body 91A is not limited to the hydraulic cylinder 96, and may be a motor, for example.

[Modification of Embodiments 1 and 2]

  In the first and second embodiments, as shown in FIGS. 4 and 7, the hinge mechanism includes a through-hole provided in the arm body on the distal end side of the two adjacent arm bodies and the two adjacent arm bodies. And a projection provided on the arm body on the proximal end side. Then, by inserting the projection into the through hole, the distal end side arm body is supported so as to be rotatable with respect to the proximal end side arm body. However, the configuration of the hinge mechanism is not limited to this, and various known configurations can be employed. For example, contrary to the first and second embodiments, a protrusion may be provided on the distal end side arm body, and a through hole may be provided on the proximal end side arm body.

  In Embodiments 1 and 2, as shown in FIGS. 4 and 7, the hinge mechanism includes a long through-hole provided in the arm body on the distal end side of two adjacent arm bodies and two adjacent arm bodies. Among them, a projection provided on the arm body on the proximal end side was provided. And by the said protrusion being penetrated by the said long through-hole, the downward rotation range with respect to the arm body of the base end side of the arm body of the front end side was restrict | limited to the 2nd attitude | position. However, the configuration of the hinge mechanism for limiting the rotation range of the arm body is not limited to this, and various known configurations can be employed. For example, contrary to the first and second embodiments, a long through hole may be provided in the arm body on the distal end side, and a protrusion may be provided on the arm body on the proximal end side. Further, for example, the hinge mechanism may include a wire rope that connects two adjacent arm bodies, and the rotation range of the arm body may be restricted in the second posture by stretching the wire rope.

  In the first and second embodiments, the boom device 14 includes one intermediate boom 22, but may include a plurality of intermediate booms 22.

  In the first and second embodiments, only the top boom 21 includes members such as an arm body (in the first embodiment, the arm body 71 and the hinge mechanism 72, and in the second embodiment, the arm body 91, the hinge mechanism 92, and the hydraulic cylinder 96). It was. However, a boom other than the top boom 21 may include a member such as the arm body. For example, all the booms included in the boom device 14 may include members such as the arm body, or only the top boom 21 and the intermediate boom 22 may include members such as the arm body.

  In the first and second embodiments, the intermediate boom 22 is expanded and contracted with respect to the base boom 23 by the telescopic cylinder 50, and the top boom 21 is expanded and contracted with respect to the intermediate boom 22 by the rope expansion and contraction mechanism 60. However, the expansion / contraction means of each boom is not limited to this. For example, all booms that expand and contract may be expanded and contracted by an expansion cylinder, or all booms that expand and contract may expand and contract by a rope expansion and contraction mechanism.

  In the first and second embodiments, the boom device 14 is mounted on the crane 10, but the boom device 14 is not limited to the crane 10. For example, the boom device 14 can be mounted on a boom-equipped vehicle such as an aerial work vehicle or a concrete crusher.

DESCRIPTION OF SYMBOLS 10 ... Crane 11 ... Work vehicle 14 ... Boom device 15 ... Outrigger device 16 ... Suspended load winch 17 ... Suspended load wire 18 ... Undulating cylinder 21 ... Top boom 22 ... Intermediate boom 23 ... Base boom 24 ... Curved surface 25 ... Boom body 26 ... Suspended wire sheave 27 ... Roller member 29 ... Hook 30 ... Suspended load 50- ..Extension cylinder 51 ... Base rod 52 ... Intermediate rod 60 ... Rope extension mechanism 61 ... Extension sheave 62 ... Extension wire rope 63 ... Shrinkage sheave 64 ... Shrink Wire rope 71 ... arm body 72 ... hinge mechanism 73 ... side plate 74 ... side plate 75 ... side plate 76 ... side plate 77 ... first projection 78 ... second projection Portion 79 ... long through hole 80 ... 1st protrusion 81 ... 2nd protrusion 82 ... Through-hole 91 ... Arm body 92 ... Hinge mechanism 93 ... Through-hole 94 ... Convex part 95 ... Protrusion 96 ... Hydraulic pressure Cylinder 101 ... Longitudinal direction 102 ... Arrow 103 ... Arrow 104 ... Arrow 105 ... Arrow

Claims (3)

Equipped with multiple booms that make up the telescopic,
At least one of the plurality of booms is
A plurality of arm bodies arranged along the longitudinal direction of the boom and two adjacent arm bodies are rotatably connected via a predetermined rotation shaft, and the arm body on the front end side is the arm on the rear end side. Boom including a hinge mechanism that allows displacement between a first posture arranged along the longitudinal direction with respect to the body and a second posture rotated downward from the first posture by its own weight. apparatus. Equipped with multiple booms that make up the telescopic,
At least one of the plurality of booms is
Two arm bodies arranged along the longitudinal direction of the boom,
A first posture in which the two arm bodies are connected to each other via a predetermined rotation shaft, and a front end arm body is disposed along the longitudinal direction with respect to a rear end arm body; and the first posture A boom apparatus comprising: a hinge mechanism that allows displacement between a second posture rotated downward from the first position; and an actuator that displaces the arm body on the distal end side to the first posture and the second posture. The boom device according to claim 1 or 2, wherein the hinge mechanism is provided on a base end side of the boom.

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