JP2009046216A - Jib crane, and its raising/lowering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a jib crane and its raising/lowering method, capable of reducing a moment acting on the vicinity of a boom foot when raising or lowering the jib crane. <P>SOLUTION: This jib crane 300 includes: a lower traveling body 301; an upper turning body 302 turnably mounted on the lower traveling body 301; a boom 303 hoistably mounted to the upper turning body 302; boom hoising means 305, 308, 316 hoisting the boom 303; a jib 304 hoistably mounted at the end of the boom 303; and jib hoisting means 310 to 314 hoisting the jib 304. When the boom 303 and jib 304 are raised from the condition in which they stretch on the ground, a supporting member 400 is interposed between the intermediate part of the jib 304 and the ground, and the intermediate part of the jib 304 is supported from the ground. Then the boom 303 is raised. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a crane with a jib, such as a luffing jib crane or a tower crane, having a boom that can be raised and lowered and a jib that can be raised and lowered at the tip of the boom, and a method for raising and lowering the crane. Is.

  Conventionally, as a crane with a jib, the thing of forms, such as a luffing jib crane and a tower crane, is known, for example. As the luffing jib crane, for example, the one described in Patent Document 1 is known. Hereinafter, a schematic configuration of the luffing jib crane according to the conventional example will be described with reference to the attached drawings. FIG. 13 is a side view of a luffing jib crane according to a conventional example.

  As shown in FIG. 13, a luffing jib crane 100 according to a conventional example has a boom 103 that can be raised and lowered mounted on a front part of a revolving body 102 that is turnably mounted on a traveling carriage 101 via a boom foot pin 103b. In addition, the crane 103 is a self-propelled crane in which a pivotable jib 104 is mounted on the boom top of the boom 103. The tip 103 a of the boom 103 is connected to the tip of the mast 105 by a guy cable 116. An upper spreader 106 is installed at the tip of the mast 105, and a lower spreader 107 is installed at the rear of the swivel body 102. A large number of boom hoisting ropes 108 are spanned between the upper spreader 106 and the lower spreader 107 via sheaves. The rear end of the boom hoisting rope 108 is wound around the boom hoisting drum 109, and the boom 103 can be hoisted by changing the distance between the upper spreader 106 and the lower spreader 107.

  A lower strut 110 is provided at the distal end portion 103 a of the boom 103, and the distal end portion of the lower strut 110 is connected to a proximal end side portion of the boom 103 by a guy cable 111. Further, an upper strut 112 is rotatably provided at the tip 103 c of the boom 103, and the tip of the upper strut 112 is connected to the tip 104 a of the jib 104 by a guy cable 113. A large number of jib hoisting ropes 114 are spanned between the distal end portion of the upper strut 112 and the distal end portion of the lower strut 110 via a sheave. The rear end of the jib hoisting rope 114 is wound around a jib hoisting drum 115 provided on the base end side of the boom 103, and the jib 104 can be hoisted by changing the angle formed by the upper strut 112 and the lower strut 110. .

  In such a luffing jib crane, an example immediately after the boom and jib are assembled and attached to the revolving structure is shown in FIG. As shown in FIG. 14, in a state immediately after assembly, the boom 203 and the jib 204 are in a state of lying on the ground. In order to shift from this state to the state where the boom 203 and the jib 204 stand up (see FIG. 13), first, the angle formed by the boom 203 and the jib 204 with the tip 204a of the jib 204 in contact with the ground. It was necessary to perform the operation of raising the boom 203 until the angle became a predetermined angle. That is, it is necessary to raise the boom 203 in a state where the distal end portion 204a of the jib 204 is supported from the ground and bring the distal end portion 204a of the jib 204 closer to the base end portion 203b side (boom foot side) of the boom 203. This is because, when the boom 203 and the jib 204 are lying on the ground, the center of gravity of the jib 204 is located away from the base end portion 203b of the boom 203, and the boom 203 and the jib 204 extend substantially in a straight line. This is because a very large force is required to raise the boom 203 as it is. That is, in this case, it is necessary to increase the output torque of the boom hoisting winch.

  By raising the boom 203 to the intermediate position as shown in FIG. 15, the tip end portion 204 a of the jib 204 is approached to the base end portion 203 b side of the boom 203 while being supported by the ground. In the intermediate posture, since the center of gravity of the jib 204 is closer to the base end portion 203b of the boom 203 than in the state shown in FIG. 14, the moment acting around the boom foot when the tip end portion 204a of the jib 204 is separated from the ground is Get smaller. Thereby, by further raising the boom 203 and the jib 204 from the intermediate posture, it is possible to shift to an upright state (see FIG. 13) in which a lifting operation or the like is possible.

  Here, in the process of shifting the boom 203 and the jib 204 shown in FIG. 14 to the intermediate posture shown in FIG. 15 from the state where the boom 203 and the jib 204 are lying on the ground (when the elevation angle of the boom 203 is the smallest). Further, the downward force in the vertical direction received by the tip 203a of the boom 203 from the jib 204 is the largest.

Therefore, conventionally, the boom standing-up operation is assisted by lifting the tip or middle portion of the boom using an assist crane or the like at the start of the boom standing-up operation. In addition, when the boom and jib are raised (see FIG. 13) to transition from the boom and jib to the ground (see FIG. 14), if the boom elevation angle is reduced, an assist crane or the like is used. Boom tilting was assisted by lifting the tip or middle part of the boom.
JP 2007-106518 A

  However, when an assist crane is used to assist the standing operation of the boom, it is necessary to lift the tip of the boom to a predetermined height and then remove the lifting tool at a high place. Even when the assist crane is used when the boom is tilted from the standing state so that the tip of the boom approaches the ground, it is necessary to attach the assist crane suspension to the boom at a predetermined height. For this reason, a facility for working at a high place is required, and the time for starting up or down the crane is increased, resulting in a problem that work efficiency deteriorates.

  On the other hand, it is conceivable to increase the output of the boom hoisting winch without using an assist crane. In this case, however, the winch speed reducer, motor, etc. are excessive than the specifications required for normal suspension work. Therefore, it is necessary to change to a high-spec one, resulting in a large cost disadvantage and an increase in size and weight.

  Although it is conceivable to increase the number of undulating ropes, it is necessary to increase the length of the wire rope, increase the number of sheaves, and increase the winding capacity of the drum. As a result, the drum becomes larger and the space required for mounting becomes larger, and the weight and cost are increased.

  The present invention was devised in view of such a problem, and an object of the present invention is to provide a crane with a jib that can reduce the moment acting around the boom foot when the crane with the jib is started up or down. It is to provide a method for starting up and shutting down.

  According to a first aspect of the present invention, there is provided a method for starting up a crane with a jib, a lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, and a liftable attachment to the upper revolving body. In a crane with a jib, the boom and the jib are on the ground. The boom and the jib are provided with a boom, a boom raising and lowering means for raising and lowering the boom, a jib that can be raised and lowered at the tip of the boom, A method for starting up the boom and the jib from a state where they are lying down, and supporting the intermediate part of the jib from the ground by interposing a support member between the intermediate part of the jib and the ground. The boom is raised in a state.

  According to this configuration, when the boom and jib stand from the ground, the middle part of the jib is supported from the ground, so that compared to the case where the tip of the jib is supported against the ground. Thus, it is possible to reduce the force in the vertically downward direction that acts on the tip of the boom from the jib. As a result, when the crane with the jib is started up, the moment acting around the boom foot is reduced, and the force required for raising the boom can be reduced.

  A method of lowering a crane with a jib according to a second aspect of the present invention includes a lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, and a undulating attachment to the upper revolving body. In a crane with a jib, the boom and the jib stand up in a crane including a boom, a boom raising and lowering means for raising and lowering the boom, a jib attached to the tip of the boom, and a jib raising and lowering means for raising and lowering the jib. In a state of supporting the intermediate part of the jib from the ground by interposing a support member between the intermediate part of the jib and the ground. The boom is tilted so that the tip of the boom approaches the ground.

  According to this configuration, since the middle part of the jib is supported from the ground when the boom and jib shift to the grounded state, the boom and jib are supported from the ground until the boom and jib transition to the grounded state. Compared with the case where the tip is supported while being in contact with the ground, it is possible to reduce the force in the vertically downward direction that acts on the tip of the boom from the jib. As a result, when the crane with jib is lowered, the moment acting around the boom foot is reduced, and the force required for tilting the boom can be reduced.

  A crane with a jib according to a third aspect of the present invention is a lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, a boom that is undulated with respect to the upper revolving body, Boom raising and lowering means for raising and lowering the boom, a jib that can be raised and lowered at the tip of the boom, jib raising and lowering means for raising and lowering the jib, and the boom and the jib in contact with the ground A support member capable of supporting the jib, and the support member is attached to an intermediate portion of the jib.

According to this configuration, since the support member is attached to the middle part of the jib, the jib tip acts on the tip of the boom in a vertically downward direction as compared with the case where the tip of the jib is supported against the ground. It becomes possible to reduce the power of. As a result, when the crane with jib is started up and down, the moment acting around the boom foot is reduced, and the force required to tilt the boom can be reduced.
In addition, since the support member is attached to the jib in advance, it is not necessary to attach or remove the support member to or from the jib when the crane is started up or down. It can be carried out.

  The crane with a jib according to a fourth invention is characterized in that the support member can be folded along the jib.

  According to this configuration, it is possible to prevent a rope or the like for suspending the suspension from the tip of the jib from being entangled with the support member. Further, it is possible to prevent the lifted luggage from coming into contact with the support member and damaging the luggage or the support member.

  The crane with a jib according to a fifth aspect of the present invention is characterized in that the support member can be folded by operating an operation portion provided at a position distant from the mounting position of the support member.

  According to this configuration, since the support member can be folded at a position away from the mounting position of the support member, the support member can be easily folded.

  In the crane with a jib according to a sixth aspect of the invention, the jib is configured by connecting a plurality of jib bodies in series, and the support member is attached to a connecting portion between two adjacent jib bodies. Features.

  According to this configuration, since the support member is attached to the connecting portion having relatively high strength in the jib, it is possible to suppress the jib from being broken or deformed by the drag received from the ground via the support member.

  A crane with a jib according to a seventh aspect of the present invention includes a connection pin that connects two adjacent jib bodies by penetrating two adjacent jib bodies, and the support member includes the connection pin via the connection pin. It is attached to a jib.

  According to this configuration, the number of parts does not increase for attaching the support member. Thereby, the crane with a jib provided with the said supporting member can be comprised at low cost. Further, the strength of the connecting pin is higher than that of other jib constituent members, and the jib can be reliably supported without being broken or deformed.

  According to the present invention, when a crane with a jib is started up and down, the moment acting around the boom foot can be reduced, and the force required for tilting the boom can be reduced.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

(Crane startup method)
FIG. 1 is a diagram for explaining a method for starting up a crane with a jib according to the present invention, and shows a state in which a boom 303 and a jib 304 are lying on the ground.
A crane 300 shown in FIG. 1 has substantially the same configuration as the luffing jib crane according to the conventional example described in FIGS. 13 to 15, and can swing freely on the lower traveling body 301 and the lower traveling body 301. A mounted upper swing body 302, a boom 303 attached to the upper swing body 302 so as to be raised and lowered, and a jib 304 attached to the distal end portion 303a of the boom 303 so as to be raised and lowered are provided. A counterweight 317 is placed at the rear of the upper swing body 302.

  The tip 303 a of the boom 303 is connected to the tip of the mast 305 by a guy cable 316. An upper spreader is installed at the tip of the mast 305, and a lower spreader is installed at the rear of the upper swing body 302. A large number of boom hoisting ropes 308 are suspended between the upper spreader and the lower spreader via sheaves. The boom 303 can be raised and lowered by winding the rear end of the boom raising and lowering rope 308 around the boom raising and lowering drum and changing the distance between the upper spreader and the lower spreader. In this way, the boom hoisting means is constituted by the mast 305, the boom hoisting rope 308, the guy cable 316, the upper spreader, the lower spreader, the boom hoisting drum, and the like.

  Further, a lower strut 310 is provided at the distal end portion 303 a of the boom 303, and the distal end of the lower strut 310 is connected to the proximal end portion of the boom 303 by a guy cable 311. Further, an upper strut 312 is rotatably provided at the distal end portion 303 c of the boom 303, and the distal end portion of the upper strut 312 is connected to the distal end portion 304 a of the jib 304 by a guy cable 313. In addition, in FIG. 1, the state which the guy cable 313 slackened is shown. A large number of jib hoisting ropes 314 are spanned between the tip of the upper strut 312 and the tip of the lower strut 310 via a sheave. The rear end of the jib hoisting rope 314 is wound around a jib hoisting drum provided on the base end 303b side of the boom 303, and the angle formed by the upper strut 312 and the lower strut 310 is changed while the guy cable 313 is stretched. The jib 304 can be undulated. Thus, the lower strut 310, the upper strut 312, the guy cables 311, 313, the jib hoisting rope 314, etc. constitute the jib hoisting means.

  The assembling method of the crane with the jib according to the present invention is such that when the boom 303 and the jib 304 are assembled, the support member 400 is interposed between the jib 304 and the ground at the middle part of the jib 304, Has a step of supporting it at a predetermined height. In the present embodiment, the support member 400 is installed closer to the base end portion 304 b than the center of gravity position G of the jib 304. And the base end part 304b of the jib 304 is urged | biased below by the dead weight of the said boom 303 from the front-end | tip part 303a of the boom 303, and is hold | maintained in the state contact | abutted on the ground. That is, the jib 304 is placed with the intermediate portion supported by the support member 400 and the tip end portion 304a of the jib 304 separated from the ground upward.

FIG. 2 is an enlarged view showing a support portion by the support member 400 in FIG. FIG. 3 is a view of the support portion shown in FIG. 2 as viewed from the direction of the arrow X, and shows the vicinity of the connecting pins 323 a and 323 b in a cross section perpendicular to the longitudinal direction of the jib 304.
As shown in FIG. 2, the support member 400 is configured by assembling a plurality of rod-shaped members to form a main body portion. Specifically, a first bar-shaped member 401 extending in the vertical direction, a second bar-shaped member 402 connected to the lower end of the first bar-shaped member at the center in the longitudinal direction, and the first bar-shaped from both ends of the second bar-shaped member 402. A pair of third rod-shaped members 403 connecting the upper ends of the members 401 constitutes a triangular portion on the side surface.

  As shown in FIG. 3, a pair of the triangular portions are arranged so as to be symmetrical when viewed from the longitudinal direction of the jib. The pair of triangular portions are coupled to each other at the upper and lower portions of the third rod-shaped member 403 by rod-shaped upper coupling members 404 and lower coupling members 405. The connecting members 404 and 405 are connected to the central portion of the upper connecting member 404 and both ends of the lower connecting member 405 by another pair of connecting members 406. Rollers 407 are provided at both ends of the second rod-shaped member 402 arranged along the ground, and are configured so that the support member 400 can be easily moved. Receiving portions 408 and 408 for contacting and supporting the jib 304 are formed at the upper ends of the pair of triangular portions, respectively. The pair of left and right receiving portions 408 and 408 are connected by a connecting member 409.

  Here, the jib 304 is configured by connecting a plurality of jib bodies in series, and each of the plurality of jib bodies is a structure in which a large number of pipe-shaped steel materials are assembled in a lattice shape. In these jib bodies, engagement metal fittings are welded to the end portions of four steel members extending in the longitudinal direction of the jib body, and two adjacent jib bodies engage the engagement metal fittings at the end portions with each other. In the combined state, they are connected by connecting pins 323a and 323b that penetrate the engaging fitting in the horizontal direction.

  The receiving portion 408 in the support member 400 is configured to be able to support a connection pin 323a for connecting an end portion of a steel material disposed on the ground side in the jib body. Specifically, it has a concave notch 408a into which the connecting pin 323a can be fitted.

  FIG. 4 is an enlarged view of a connecting portion by the connecting pin 323a shown in FIG. As shown in FIG. 4, two adjacent jib bodies have a bifurcated engagement fitting 321 welded to the end of one jib, and an engagement fitting 322 welded to the end of another jib. In the fitted state, the connecting pins 323a are connected by being penetrated in a substantially horizontal direction. Both end portions of the connecting pin 323a protrude from the engagement fitting 321. The support member 400 can support the jib 304 in the vertical direction by fitting both ends of the connection pin 323a into the notch 408a of the receiving portion 408.

  The connecting pin 323a may be changed to a shape that is easily supported by the receiving portion 408. For example, as shown in FIG. 5, the connecting pin may be changed to a pin 324 that is longer than the pin used for normal joining so that the support by the support member 400 is stabilized. Further, the present invention is not necessarily limited to the case of supporting the connecting pin, and the frame portion forming the jib may be supported.

  As described above, the jib 304 is supported by the support member 400 at the middle portion in the longitudinal direction of the jib 304. The position of the center of gravity of the jib 304 is located closer to the tip end 304 a side of the jib 304 than the support position by the support member 400. As a result, the jib 304 is moved so that the tip end 304a of the jib 304 approaches the ground and the base end portion 304b moves away from the ground, that is, in the direction indicated by the arrow R1 in FIG. The force of tilting forward will act. Thereby, the front-end | tip part 303a of the boom 303 receives force in the direction away from the ground from the base end part 304b of the jib 304. Therefore, when the boom 303 is erected from the state shown in FIG. 1, the moment centering on the base end portion of the boom 303 acting on the boom 303 can be reduced.

  As shown in FIG. 1, a tip support device 320 capable of supporting the tip of the jib from the ground via a roller is installed at the tip of the jib 304, and the boom 303 is erected to support the tip support device. Until 320 comes into contact with the ground, the above-described force that tilts the jib 304 forward acts. FIG. 6 shows a state where the boom 303 is erected from the state shown in FIG. 1 and the tip support device 320 is in contact with the ground.

  The state shown in FIG. 6 is a state immediately before the jib 304 is separated upward from the support member 400 during the standing operation of the boom 303. The jib 304 is supported from the ground via the distal end support device 320 at the distal end portion 304a, and is supported by the distal end portion 303a of the boom 303 at the proximal end portion 304b. When the boom 303 is further raised from this state, the jib 304 is separated upward from the support member 400, and the base end portion 303b of the boom 303 is supported while the front end portion 304a of the jib 304 is supported on the ground via the front end support device 320. It moves to approach the side. Then, with the tip 304a of the jib 304 supported from the ground via the tip support device 320, the boom 303 is raised to an intermediate position (see FIG. 15), and then the tip 304a of the jib 304 is lifted. By further raising the boom 303 and the jib 304, the state moves to an upright state (see FIG. 13) where a lifting operation or the like is possible, and the crane startup operation is completed.

  Here, in the standing operation of the boom 303, the position of the center of gravity of the boom 303 approaches the base end portion 303b side of the boom 303 as the standing operation proceeds from the state shown in FIG. The force required for the boom 303 is the largest when the boom 303 starts to stand up. And the front-end | tip part 303a of the boom 303 leaves | separates from the ground, and it becomes small gradually as the elevation angle of the boom 303 becomes large. Therefore, by supporting the jib 304 by the support member 400 at the start of the standing motion of the boom 303, the maximum value of the force required for the standing motion of the boom 303 can be reduced. That is, the largest moment acts on the boom 303 at the start of the standing motion of the boom 303. By supporting the jib 304 with the support member 400 at the start of the standing motion of the boom 303, the boom 303 is applied to the boom 303 at the standing motion. It is possible to reduce the maximum value of the acting moment.

  In the above-described crane start-up method, the support member 400 is installed closer to the base end portion 304b of the jib 304 than the center of gravity position G of the jib 304. You may install in the front-end | tip part 304a side. Even in this case, at least a force for tilting the jib 304 forward with the support member 400 as a fulcrum acts due to the own weight of the jib constituent member located on the tip 304a side of the jib 304 relative to the support member 400. Therefore, the base end 304b of the jib 304 can be lifted with a smaller force than when the base end 304b of the jib 304 is lifted (see FIG. 14) while the tip 304a of the jib 304 is supported from the ground. it can. Thereby, it becomes possible to reduce the maximum value of the moment acting on the boom 303 during the standing operation up to the working posture.

  The shape of the support member 400 and the mounting position of the support member can be changed as appropriate, but the support member 400 is supported so that the boom 303 is supported by the support member until the boom 303 is tilted by about 10 to 20 degrees with respect to the ground. It is desirable to determine the attachment position of the member and the support member. In this range, the vertical downward force acting on the boom 303 from the jib 304 when the elevation angle of the boom 303 is small can be reduced, and the support position of the jib 304 is not excessively increased, and the lower position. This is because the jib 304 can be stably supported.

(How to lower the crane)
The method of lowering the crane with jib according to the present invention can be implemented by performing the reverse process of the method of starting the crane with jib according to the present invention and lowering the crane from the standing state. That is, when the boom 303 is tilted so that the tip 303a of the boom 303 approaches the ground, the support member 400 is installed between the jib 304 and the ground as shown in FIG. Thus, the intermediate portion of the jib 304 is supported, and further, the boom 303 is tilted so that the tip 303a of the boom 303 approaches the ground, and is shifted to the state shown in FIG. Can implement the method of falling.

  As a result, when the crane is lowered, after the jib 304 is supported by the support member 400, the vertical end received from the jib 304 at the distal end 303a of the boom 303 until the base end 304b of the jib 304 comes into contact with the ground. The downward force can be reduced. As described above, in particular, when the support position by the support member 400 is on the base end portion 304b side with respect to the center of gravity position of the jib 304, the tip end portion is connected from the base end portion 304b of the jib 304 to the tip end portion 303a of the boom 303. This is effective because force can be applied in the direction of separating 303a from the ground.

(First embodiment of crane with jib)
Next, the jib crane according to the first embodiment of the present invention will be described. FIG. 7 shows a crane 1 with a jib according to the first embodiment of the present invention. FIG. 8 is an enlarged view showing a support portion by the support member 31 in FIG. In the crane 1 shown in FIG. 1, a member corresponding to the support member 400 is integrally formed with the jib 304 in the crane 300 shown in FIG. 1, and the other configurations are the same as the crane 300. Reference numerals are assigned and description is omitted.

  As shown in FIG. 7, the jib 2 in the crane 1 includes a lower jib body 21 connected to the boom 303, an upper jib body 26 located on the tip side of the jib 2, and the lower jib body 21 and the upper jib body 26. The four intermediate jib bodies 22, 23, 24, and 25 disposed between the two are connected in series. Each of these jib bodies 21 to 26 is a structure in which a large number of pipe-shaped steel materials are assembled in a lattice shape. In these jib bodies, engagement metal fittings are welded to the end portions of four steel members extending in the longitudinal direction of the jib body, and two adjacent jib bodies engage the engagement metal fittings at the end portions with each other. In the combined state, they are connected by connecting pins 32a and 32b that penetrate the engaging fitting in the horizontal direction (see FIG. 8). In addition, the length of the whole jib 2 can be adjusted according to a use by adjusting the number and length of an intermediate jib body.

  A support member 31 is attached at a connecting portion between the intermediate jib body 25 connected to the upper jib body 26 and the intermediate jib body 24 adjacent to the intermediate jib body 25. The position where the support member 31 is attached is located closer to the base end 2b side of the jib 2 than the center of gravity position G of the jib 2.

  As shown in FIG. 8, the support member 31 is rotatable with respect to the jib 2 via a connecting pin 32a for connecting the ends of the steel materials disposed on the ground side in the intermediate jib bodies 24, 25. It is attached. A pair of support members 31 are provided on the left and right sides of the jib 2.

  The support member 31 includes a vertex portion 31a having a through-hole through which the connecting pin 32a passes, a bottom portion 31b that is a portion in contact with the ground, and a central portion of the bottom portion 31b that is disposed perpendicular to the bottom portion 31b. The central support member 31c that connects the apex portion 31a and the pair of end support members 31d that connect the apex portion 31a and the vicinity of both ends of the bottom portion 31b are configured in a substantially triangular shape in side view. In addition, you may comprise the base part 31b contact | abutted on the ground so that the contact area with the ground may become large with a plate-shaped member.

  By integrally configuring the jib 2 and the support member 31 as described above, the tip 2a of the jib 2 contacts the ground as described in the embodiment of the crane start-up / down method according to the present invention. Compared to the case where the contact is supported (see FIG. 14), it is possible to reduce the force in the vertically downward direction that acts on the tip 303a of the boom 303 from the jib 2. As a result, it is possible to reduce the moment acting around the boom foot when the jib crane is started up and down. Moreover, since the jib 2 and the support member 31 are integrally connected, it is not necessary to attach or remove the support member 31 to or from the jib 2 when the crane is started up or down.・ Easy to carry out the shutdown work.

  The height h of the support member 31 (the length from the center of the through hole into which the connecting pin 32a is inserted in the apex portion 31a to the contact surface with the ground in the bottom portion 31b) is the length of the boom 303 and the jib 2. It is determined as appropriate based on such factors. For example, when the jib 2 is tilted forward with the support member 31 as a fulcrum and the tip 2a of the jib 2 comes into contact with the ground, the elevation angle of the boom 303 with respect to the ground is within a range of 10 to 20 degrees. It is desirable to determine a height h of 31. In this case, by configuring the support member 31 so that the elevation angle of the boom 303 becomes 10 degrees or more, the downward downward force acting on the boom 303 from the jib 2 that becomes larger as the elevation angle of the boom 303 becomes smaller is reduced. Can do. Further, by configuring the support member 31 so that the elevation angle of the boom 303 is 20 degrees or less, the jib 2 is supported at a lower position, and as a result, the tilt of the jib 2 in the state supported by the support member 31. Since it can suppress that becomes large too much, the jib 2 can be supported stably.

  The support member 31 is attached to a connecting portion between the intermediate jib body 24 and the intermediate jib body 25. In the said connection part, the arrangement | positioning density of the pipe-shaped steel materials which comprise an intermediate | middle jib body is high, and the intensity | strength is formed high compared with the longitudinal direction intermediate position of an intermediate | middle jib body. Therefore, it is possible to suppress the jib 2 from being broken or deformed by a drag received from the ground via the support member 31.

  Further, since the support member 31 is attached to the jib 2 via the connecting pins 32a that connect the adjacent intermediate jib body 24 and the intermediate jib body 25 by penetrating in the horizontal direction, the support member 31 is attached. Therefore, the number of parts does not increase. Thereby, the support member 31 can be attached at low cost. Moreover, since the strength of the connecting pin 32a is higher than other jib constituent members, the jib 2 can be reliably supported without being broken or deformed.

(Second embodiment of crane with jib)
Next, a jib crane according to a second embodiment of the present invention will be described. The crane with a jib according to the second embodiment is different from the crane with a jib according to the first embodiment in that a foldable support member 33 is provided. Since the other parts have the same configuration as that of the first embodiment, the same members are denoted by the same reference numerals and the description thereof is omitted.

FIG. 9 is an enlarged view of a support portion by the support member 33 in the crane with a jib according to the second embodiment. Moreover, FIG. 10 is a YY partial cross-sectional arrow view in FIG.
The support member 33 includes a bracket 34 fixed to the jib so as to extend from the jib 2 to the ground side using a connection pin 32a and the like, and a rod-like member whose one end is rotatably connected to the bracket 34. 35 and a link mechanism 36 for connecting the rod-shaped member 35 and the jib 2 to each other on both the left and right sides of the jib 2. As shown in FIG. 10, the pair of left and right bar-shaped members 35 are connected by a bar-shaped upper connecting member 37a and a lower connecting member 37b. Further, the central portion of the upper connecting member 37a and both end portions of the lower connecting member 37b are connected by another pair of connecting members 38. A roller 39 is installed at the end of the rod-shaped member 35 opposite to the bracket 34 side.

  The link mechanism 36 is configured by connecting two rod-like link constituent members with pins, and when the rod-like member 35 rotates in the direction indicated by the arrow R2, the longitudinal direction of the rod-like member 35 and the longitudinal direction of the jib 2 are configured. It is configured to extend in a straight line at a position where the direction is substantially perpendicular to restrain the rotation of the rod-shaped member 35. Further, the support member 33 can be folded and arranged along the jib 2 by rotating the rod-shaped member 35 in the direction indicated by the arrow R3 in FIG. In FIG. 9, the folded support member 33 is indicated by a two-dot chain line.

  Thus, since the support member 33 is configured to be foldable along the jib 2, the support member 33 is folded from the jib 2 in the direction perpendicular to the longitudinal direction of the jib 2 by folding the support member 33. The length of protruding can be shortened. Thereby, it is possible to prevent a rope or the like for suspending the hanging tool from the tip of the jib 2 from being entangled with the support member 33. Further, it is possible to prevent the lifted luggage from coming into contact with the support member 33 and damaging the luggage or the support member 33.

  FIG. 11 schematically illustrates a modification of the support member 33 according to the second embodiment. As shown in FIG. 11, the support member 40 according to the modification is rotatably connected via a connecting pin 32a. The support member 40 is connected to the jib 2 via wires 41 and 41 connected to the vicinity of the end opposite to the connection pin 32a. In the state shown in FIG. 11, the rotation of the support member 40 is restrained by the wires 41 and 41, and the jib 2 can be supported from the ground. Further, by removing the wires 41 and 41, the support member 40 can be rotated, and the support member 40 can be rotated and fixed along the jib 2.

  Further, as schematically shown in FIG. 12, the wire 43 connected to the support member 40 is provided near the tip of the jib 2 through sheaves 44 and 45 provided on the jib 2. It is also possible to adopt a configuration wound around the drum 46. The drum 46 is configured to be able to fix the movement of the wire 43, and by fixing the movement of the wire 43, the rotation of the support member 40 connected to the wire 43 can be restricted. Further, the drum 46 is provided with a handle 47 as an operation unit, and the wire 43 can be moved by rotating the handle 47 to rotate the drum 46. For example, in a state where the jib 2 is not supported by the support member 40, the drum 46 is rotated in the direction indicated by the arrow R4 in FIG. 12, and the wire portion 43a extending from the support member 40 toward the tip 2a side of the jib 2 is drummed. The support member 40 can be folded along the jib 2 by pulling in on the 46 side (arrow A1 direction). Further, the support member 40 can be extended from the jib 2 by rotating the drum 46 in the reverse direction while the support member 40 is folded along the jib 2.

  Here, when the boom is further raised from the state where the tip 2a of the jib 2 is in contact with the ground shown in FIG. 12, the base end of the jib 2 is lifted with the tip 2a as a fulcrum. The support member 40 attached to the intermediate part is levitated from the ground. In this case, the work of folding the support member 40 at the position of the support member 40 that has floated becomes a high place work, and the work efficiency may deteriorate. In this regard, since the handle 47 is installed in the vicinity of the tip of the jib 2, the position of the handle 47 is lower than the position of the support member 40 that has floated if the tip 2 a of the jib 2 is grounded. It becomes. Therefore, the work of turning the handle 47 to fold the support member 40 becomes easy, and the work efficiency can be improved. In addition, when the operation member such as the handle 47 is installed at least on the distal end side of the jib 2 from the attachment position of the support member 40, the folding operation is performed at a position lower than the support member 40 when the support member 40 floats. Is possible.

  In addition, since the folding operation can be performed at a position away from the support member 40 due to the mechanical configuration using the wire 43, malfunction or the like hardly occurs.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

It is a figure for demonstrating the starting method of the crane with a jib which concerns on this invention. It is an enlarged view of the support part by the support member in FIG. It is the figure which looked at the support part in FIG. 2 from the arrow X direction. It is an enlarged view of the connection part by the connection pin shown in FIG. It is a figure which shows the modification of the connection pin shown in FIG. It is a figure which shows the state which the front-end | tip support apparatus of the jib contact | abutted to the ground. The crane with a jib concerning a 1st embodiment of the present invention is shown. It is an enlarged view of the support part by the support member in FIG. It is an enlarged view of the support part by the support member in the crane with a jib which concerns on 2nd Embodiment. It is a YY partial cross section arrow view in FIG. It is a figure which shows typically the modification of the supporting member which concerns on 2nd Embodiment. It is a figure which shows typically the modification of the supporting member which concerns on 2nd Embodiment. It is a side view of the luffing jib crane which concerns on a prior art example. It is a figure which shows an example of the state immediately after assembling a boom and a jib and attaching to a turning body. It is a figure which shows the intermediate position of a crane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crane 2 Jib 31 Support member 32a, 32b Connection pin 40 Support member 47 Handle (operation part)
301 Lower traveling body 302 Upper turning body 303 Boom 304 Jib 305 Mast 308 Boom hoisting rope 310 Lower struts 311, 313, 316 Guy cable 312 Upper strut 314 Jib hoisting rope 323a, 323b Connecting pin 400 Support member

Claims (7)

A lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, a boom that is undulated with respect to the upper revolving body, a boom hoisting means for raising and lowering the boom, In a crane with a jib comprising a jib that can be raised and lowered at the tip of a boom, and a jib hoisting means for raising and lowering the jib, when the boom and the jib are raised from a state where the boom and the jib are lying on the ground A startup method,
A method for starting up a crane with a jib, wherein a support member is interposed between an intermediate portion of the jib and the ground, and the boom is raised in a state where the intermediate portion of the jib is supported from the ground. A lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, a boom that is undulated with respect to the upper revolving body, a boom hoisting means for raising and lowering the boom, In a jib crane having a jib that can be raised and lowered at the tip of a boom and a jib raising and lowering means for raising and lowering the jib, the boom and the jib are lowered when the boom and the jib are shifted from a standing state to a grounded state. A method,
A support member is interposed between the middle part of the jib and the ground, and the boom is tilted so that the tip of the boom approaches the ground with the middle part of the jib supported from the ground. How to set up a crane with a jib. A lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, a boom that is undulated with respect to the upper revolving body, a boom hoisting means for raising and lowering the boom, A jib that can be raised and lowered at the tip of the boom, jib raising and lowering means for raising and lowering the jib, and a support member that can support the jib by abutting against the ground when the boom and the jib are lying on the ground. ,
The crane with a jib, wherein the support member is attached to an intermediate portion of the jib.   The crane with a jib according to claim 3, wherein the support member is foldable along the jib.   The crane with a jib according to claim 4, wherein the support member is foldable by operating an operation portion provided at a position distant from a mounting position of the support member. The jib is configured by connecting a plurality of jib bodies in series,
The said supporting member is attached to the connection part of two adjacent jib bodies, The crane with a jib as described in any one of Claim 3-5 characterized by the above-mentioned. A connecting pin that connects the two adjacent jib bodies by penetrating each of the two adjacent jib bodies,
The said support member is attached to the said jib through the said connection pin, The crane with a jib as described in any one of Claim 3-6 characterized by the above-mentioned.

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