Jib Fixing Device

Abstract

To provide a jib fixing device which comparatively facilitates fixation of a job to a boom and release of the fixation, facilitates assembly and disassembly of a crane, and can suppress damage of a member for fixing the jib to the boom.SOLUTION: A jib fixing device of a tower crane for bending and fixing a jib derrickingly mounted on a tip side of a boom, to the boom has a jib side fixation part that is arranged on the jib and includes a fixation pin, and a boom side fixation part that is arranged on the boom and includes an engagement pin movable between an engagement position with the fixation pin and a release position where engagement with the fixation pin is released, and at least one of the fixation pin and the engagement pin has a flattened part on its outer peripheral surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a jib fixing device. [Background technology]

[0002] As large cranes, there are known large cranes such as luffing jib cranes with a jib at the end of a boom, tower cranes, etc. The boom and jib of the large cranes are assembled and disassembled at the work site where they are used.

[0003] Generally, there are two types of boom and jib assembly and disassembly: one in which the jib is extended in a straight line from the boom, called the extended position, and one in which the jib is folded up against the boom, called the tucked-in position. The tucked-in position allows the work to be done in a relatively small space.

[0004] The boom and jib assembled in the tucked-in position are fixed to each other when the boom is raised and lowered, and the jib can be raised and lowered relative to the boom by releasing the fixation. To disassemble the boom and jib in the tucked-in position, the folded jib is fixed to the boom and integrated, allowing the boom and jib to be safely lowered to the ground.

[0005] A safety device has been proposed to prevent the boom and jib from being damaged by the jib colliding with the ground when the boom and jib fixed in an inward hoisting position are lowered (JP Patent Publication 2006-176242). This safety device is equipped with a detector on the boom and a detector body on the boom and jib, and is activated when the detector detects the displacement of the detector body caused by the jib hitting the ground, thereby stopping the boom lowering operation.

[0006] The boom and jib described in the above publication are fixed in a folded state by a latch mechanism having a hanger pin arranged on the jib and a latch pin arranged on the boom and engageable with the hanger pin. The weight of the fixed jib is applied to the hanger pin and the latch pin when the boom is in a collapsed state, which makes it difficult to engage and release the hanger pin and the latch pin, which may make it difficult to assemble and disassemble the boom and jib. In addition, the hanger pin and the latch pin may be deformed or worn. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-176242 A Summary of the Invention [Problem to be solved by the invention]

[0008] In consideration of the above-mentioned circumstances, the present invention aims to provide a jib fixing device that makes it relatively easy to fix and release a jib to a boom, facilitates assembly and disassembly of the crane, and suppresses damage to the members that fix the jib to the boom. [Means for solving the problem]

[0009] One aspect of the present invention made to solve the above problems is a jib fixing device for a tower crane that bends and fixes a jib, which is attached to the tip of the boom in a manner that allows it to be raised and lowered, relative to the boom, and has a jib side fixing part that is arranged on the jib and includes a fixing pin, and a boom side fixing part that is arranged on the boom and includes an engagement pin that is movable between an engagement position with the fixing pin and a release position where the engagement with the fixing pin is released, and at least one of the fixing pin and the engagement pin has a flat portion on its outer circumferential surface.

[0010] In the jib fixing device, at least one of the fixing pin and the engagement pin has a flat portion on its outer circumferential surface, so that the load on the fixing pin and the engagement pin can be made relatively small. Also, because the load is small, the engagement pin can be moved relatively easily. Effect of the Invention

[0011] The jib fixing device of the present invention makes it relatively easy to fix and release the jib to the boom, making it easy to assemble and disassemble the crane and preventing damage to the member fixing the jib to the boom. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic side view showing a crane equipped with a jib fixing device of one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic front view showing a jib fixing device according to one embodiment of the present invention. [Diagram 3] 3 is a partial cross-sectional side view of the jib fastening device of FIG. 2, showing a state in which the fastening of the jib to the boom has been released. FIG. [Figure 4] FIG. 4 is a partial cross-sectional view showing the state immediately before the jib is fixed to the boom or released from the same in the jib fixing device of FIG. [Diagram 5] FIG. 5 is a partial cross-sectional view showing a state in which the jib is fixed to the boom in the jib fixing device of FIG. [Figure 6] FIG. 6 is a schematic side view showing an engagement pin of a jib fixing device according to one embodiment of the present invention. [Figure 7] FIG. 7 is a schematic plan view of the engagement pin of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

[0014] [crane] Fig. 1 shows the configuration of a crane 50 equipped with a jib fixing device 1 according to one embodiment of the present invention. This crane 50 is a luffing jib crane mainly including a lower traveling body 51, an upper rotating body 52 mounted on the lower traveling body 51 and capable of rotating in a plane parallel to the plane on which the lower traveling body 51 travels, a boom 53 disposed on the upper rotating body 52 and capable of being raised and lowered in the front-rear direction (swinging so as to collapse to the front and stand up to the rear), and a jib 54 connected to the tip of the boom 53 and capable of being raised and lowered in the front-rear direction. Fig. 1 shows a state in which the crane 50 folds the jib 54 relative to the boom 53 and lowers the boom 53.

[0015] [Lower running body] The lower traveling body 51 has a pair of crawlers or the like as a traveling device and can move in any direction.

[0016] [Upper rotating body] The upper rotating body 52 is mounted on the lower running body 51 and can rotate in a plane parallel to the plane along which the lower running body 51 travels. The upper rotating body 52 has an operator's cabin, a boom hoisting winch for raising and lowering the boom 53, a jib hoisting winch for raising and lowering the jib 54, a hoisting winch for sending out and winding up the hoisting cable suspended from the tip of the jib 54, and the like. The "traveling surface" refers to, for example, the ground, and in the case where the vehicle travels on the surface (top surface) of an iron plate or the like laid on the ground, it means that surface. The "parallel surfaces" includes two completely parallel surfaces, as well as a surface that is slightly inclined with respect to the plane along which the lower running body 51 travels due to design tolerances, manufacturing errors, and the like in the lower running body 2 and the upper rotating body 52.

[0017] 〔boom〕 The boom 53 has a base end connected to the upper rotating body 52 and rises and falls perpendicular to the plane of rotation of the upper rotating body 52. ​​The boom 53 has an upper boom connected to the jib 54 at its tip end, one or more intermediate booms that form a straight body portion in the center in the longitudinal direction, and a lower boom connected to the upper rotating body 52 and having a tapered shape.

[0018] The upper boom, the lower boom and the intermediate boom are formed in a roughly rectangular tubular shape, and have, for example, a lattice structure. The lattice structure has four boom main girders (pillars or main columns) arranged so as to be located at the vertices of an imaginary square in a cross section perpendicular to the longitudinal direction, and a plurality of boom auxiliary girders (lattices or diagonal members) arranged so as to connect adjacent boom main girders to form a plurality of triangles, rectangles, etc. with the boom main girders as their bases. The upper boom and the lower boom may be made of plate-shaped reinforcing members instead of the plurality of boom auxiliary girders. The upper boom, the lower boom and the intermediate boom are assembled into one boom 53 by connecting the ends of the boom main girders together.

[0019] 〔jib〕 The base end of the jib 54 is connected to the tip of the boom 53. Like the boom 53, the jib 54 can be raised and lowered perpendicularly to the plane of rotation of the upper rotating body 52, and a lifting cable suspends from its tip. The jib 54 has a lower jib connected to the boom 53, one or more intermediate jibs that form a straight body portion in the center of the longitudinal direction, and an upper jib on the tip side. The lower jib and upper jib are tapered.

[0020] The lower jib, intermediate jib and upper jib are formed in a roughly rectangular tubular shape, similar to the boom 53, and have, for example, a lattice structure. The lattice structure has four jib main girders arranged to be located at the vertices of an imaginary square in a cross section perpendicular to the longitudinal direction, and a plurality of jib auxiliary girders arranged to connect adjacent jib main girders to form a plurality of triangles, rectangles, etc. with the jib main girders as the base. The lower jib and upper jib may be plate-shaped reinforcing members instead of the plurality of jib auxiliary girders. The lower jib, intermediate jib and upper jib are assembled into a single jib 5 by connecting the ends of the jib main girders together.

[0021] [Jib fixing device] 2 to 5, the jib fastening device 1 is disposed on the jib 54 and has a jib side fixing part 10 including a fixing pin 11, and a boom side fixing part 20 disposed on the boom 53 and including an engagement pin 21 movable between an engagement position with the fixing pin 11 and a release position where the engagement with the fixing pin 11 is released. Fig. 2 is a schematic plan view of the jib fastening device 1 when viewed from the tip side to the base end side of the boom 53.

[0022] The location where the jib fastening device 1 is disposed is not particularly limited, but is preferably a location where the ventral side of the boom 53 and the ventral side of the jib 54 abut or are closest to each other when the jib 54 is folded relative to the boom 53. Specifically, for example, within area A in Fig. 1 of the adjacent intermediate boom and intermediate jib, the boom side fixing part 20 is disposed on the ventral side of the boom 53, and the jib side fixing part 10 is disposed on the ventral side of the jib 54. Note that the "ventral side" means the side that is vertically below the boom 53 and jib 54 (the side closest to the ground) when the jib 54 is extended and the boom 53 and jib 54 are lowered.

[0023] (jib side fixing part) The jib side fixing part 10 is disposed on the jib 54 and includes a fixing pin 11. Specifically, the fixing pin 11 is attached between the two jib main girders 54a on the ventral side of the four jib main girders, with the radial center axis being approximately parallel to the width direction of the jib 54. The fixing pin 11 is an approximately cylindrical member. Note that the "width direction of the jib 54" means the direction perpendicular to the longitudinal direction of the jib 54 in an imaginary plane including the two jib main girders 54a on the ventral side.

[0024] More specifically, the jib 54 has a jib side beam member 12 that is spanned between two jib main girders 54a on the ventral side. The jib side beam member 12 has a pair of brackets 13 that are erected toward the boom 53. The pair of brackets 13 have through holes and grip both ends of the fixing pin 11 inserted into the through holes.

[0025] (Boom side fixing part) The boom side fixing part 20 is disposed on the boom 53 and includes an engaging pin 21 that is movable between an engaging position with the fixing pin 11 and a releasing position where the engagement with the fixing pin 11 is released. Specifically, the engaging pin 21 is provided between two boom main girders 53a on the ventral side of the four boom main girders, with its radial center axis approximately parallel to the longitudinal direction of the boom 53. The engaging pin 21 is a substantially cylindrical member.

[0026] More specifically, the boom 53 has a boom side beam member 22 that is bridged between two boom main girders 53a on the ventral side. The boom side beam member 22 has a cylindrical casing 23 and a support frame 24 in the middle part.

[0027] The cylindrical casing 23 includes therein a pressing member 25 that is movable in the height direction (directions perpendicular to the longitudinal direction and width direction of the boom 53). One surface of the pressing member 25 abuts against the fixed pin 11, and the other surface is biased toward the jib 54 by a pressing biasing member 26 such as a spring.

[0028] The casing 23 has a pair of insertion holes 23a near the end on the side close to the jib 53, through which the engagement pins 21 are inserted.

[0029] The support frame 24 is disposed approximately parallel to the boom main girder 53a, and rotatably holds the engagement lever 27 at its tip. The engagement lever 27 is supported at its middle portion by the tip of the support frame 24. One end of the engagement lever 27 is connected to one end of the engagement pin 21. One end side of the engagement lever 27 is biased toward the casing 23 by a lever biasing member 29 such as a spring. The other end of the engagement lever 27 is connected to a wire 28 that can be operated by the operator of the crane 50.

[0030] To fix the jib 54 in the folded state to the boom 53, the operator brings the ventral side of the jib 54 close to the ventral side of the boom 53, and manipulates the wire 28 so that the other end (tip) of the engagement pin 21 does not protrude into the inner surface of the casing 23. That is, the engagement pin 21 moves to the release position by the operation of the operator (FIG. 3).

[0031] When the fixing pin 11 of the folded jib 54 comes into contact with the pressing member 25 and is pushed into the boom 53, and the entire outer circumferential surface of the fixing pin 11 passes through the insertion hole 23a, the operator stops the above operation (Fig. 4). The engagement pin 21 enters the casing 23 by the bias of the lever biasing member 29 and penetrates the casing 23. That is, the engagement pin 21 moves to the engagement position (Fig. 5). In this way, by engaging the fixing pin 11 with the engagement pin 21, the jib 54 in the folded state can be fixed so that it cannot be raised or lowered.

[0032] In order to facilitate engagement with the fixed pin 11, it is preferable that the tip of the engagement pin 21 is chamfered.

[0033] At least one of the fixed pin 11 and the engagement pin 12 has a flat portion on its outer circumferential surface. The fixed pin 11 and the engagement pin 12 are both substantially cylindrical members and engage with each other so that the contact points are substantially in point contact. When the boom 53 is vertically raised and lowered, no load is applied to the fixed pin 11 and the engagement pin 12. However, if the boom 53 is lowered even slightly, the weight of the jib 54 is applied to the contact points of the fixed pin 11 and the engagement pin 12. For this reason, the fixed pin 11 and the engagement pin 12 may be deformed, and the engagement pin 12 may be difficult to move. By having at least one of the fixed pin 11 and the engagement pin 12 have the flat portion on their outer circumferential surface, the contact points can be in line contact, and the load (weight of the jib 54) applied to the fixed pin 11 and the engagement pin 12 can be reduced. If the fixed pin 11 and the engagement pin 12 each have the flat portion, the contact points can be in surface contact, and the load can be further reduced.

[0034] It is preferable that the fixed pin 11 and the engagement pin 12 abut on the flat portion. In other words, it is preferable that the flat portion is formed at the portion where the fixed pin 11 and the engagement pin 12 engage with each other and abut on each other. In this way, the load applied to the fixed pin 11 and the engagement pin 12 can be reliably reduced.

[0035] 6 to 7, it is preferable that the engagement pin 21 has a flat portion F. One end of the engagement pin 21 forms a connecting portion 21a that connects with one end of the engagement lever 27, and therefore a contact point with the fixed pin 11 is planned. Therefore, the portion that forms the flat portion F can be easily specified.

[0036] When the engagement pin 21 has the flat portion F and the fixing pin 11 does not have a flat portion, it is preferable that each of the through holes of the pair of brackets 13 has a bearing that allows the fixing pin 11 to rotate freely in the circumferential direction. In this way, the movement of the engagement pin 21 can be facilitated.

[0037] The flat portion F is formed at least at the contact point with the fixed pin 11. It is preferable that the flat portion F is formed from the tip portion beyond the contact point with the fixed pin 11. In this way, the movement of the engagement pin 21 can be facilitated and the load applied to the engagement pin 21 during the movement can be reduced.

[0038] The width W of the flat portion F is not particularly limited and depends on the diameter, material, etc. of the engagement pin 21. For example, the lower limit is preferably 5 mm, and more preferably 8 mm. The upper limit is preferably 20 mm, more preferably 15 mm, and even more preferably 12 mm. If the width W of the flat portion F is less than the lower limit, the load on the contact point may not be effectively reduced. On the other hand, if the width W of the flat portion F exceeds the upper limit, the strength of the engagement pin 21 may decrease, and the engagement pin 21 may be deformed. The "width of the flat portion F" refers to the distance in a direction perpendicular to the radial center axis of the engagement pin 21.

[0039] [advantage] In the jib fixing device 1, at least one of the fixed pin 11 and the engaging pin 21 has a flat portion on the outer circumferential surface, so that the load on the fixed pin 11 and the engaging pin 21 can be reduced to suppress deformation, etc. This makes it possible to reduce the maintenance costs of the jib fixing device 1. In addition, because the load is small, it is relatively easy to move the engaging pin 21 between the engagement position and the disengagement position with respect to the fixed pin 11, making it easy to fix the jib 53 to the boom 54. This makes it easy to assemble and disassemble the boom 54 and jib 53 in the crane 50.

[0040] [Other embodiments] The above-mentioned embodiment does not limit the configuration of the present invention. Therefore, the above-mentioned embodiment may omit, replace or add components of each part of the above-mentioned embodiment based on the description in this specification and common technical knowledge, and it should be understood that all of these are within the scope of the present invention.

[0041] In the above embodiment, the boom 53 and the jib 54 have been described as having a lattice structure, but the jib fastening device 1 may also be of the telescopic type boom and jib.

[0042] The method for assembling a crane can also be applied to assembling a tower crane that does not raise or lower the boom during use. [Industrial Applicability]

[0043] The jib fixing device according to the present invention is particularly suitable for use with large luffing jib cranes. [Explanation of symbols]

[0044] 1 Jib fixing device 10 Jib side fixing part 11 Fixing pin 12 Jib side beam member 13 Bracket 20 Boom side fixing part 21 Engagement pin 21a Connecting part 22 Boom side beam member 23 Casing 23a Insertion hole 24 Support frame 25 Pressing member 26 Pressing biasing member 27 Engagement lever 28 Wire 29 Lever biasing member 50 Crane 51 Undercarriage 52 Upper rotating body 53 Boom 53a Boom main girder (ventral side) 54 Jib 54a Jib main girder (ventral side) Area A (location of jib fixing device) F flat area W Width of flat part F

Claims

1. A jib fixing device for a tower crane that bends and fixes a jib that is attached to the tip side of a boom so that it can be raised and lowered relative to the boom, The boom and the jib have a lattice structure, A jib side fixing part disposed on the ventral side of the jib and including a fixing pin; a boom side fixing part including an engagement pin that is disposed on the ventral side of the boom and is movable between an engagement position with the fixing pin and a release position where the engagement with the fixing pin is released such that the axial direction of the engagement pin is perpendicular to that of the fixing pin; having The engagement pin has a flat portion on an outer circumferential surface, A jib fixing device in which the jib side fixing part holds the fixing pin so that it can rotate freely in the circumferential direction.

2. The jib fixing device according to claim 1, wherein the fixing pin and the engagement pin abut at the flat portion.

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