JP2013049499A - Crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate an assembly operation of a crane having a backstop.SOLUTION: A guide member 70 is rotatably pivoted by the own weight in the vicinity of a receiving part 61 being an abutment part of a target 60, guides the other end 52 of a backstop 50 to the receiving part 61 during a crane operation, guides the other end 52 of the backstop 50 so that it does not abut against the receiving part 61 during the disassembly of the crane, and guides the other end 52 of the backstop 50 by supporting it from below during the assembly of the crane. A magnet 81 attracts the guide member 70 by magnetic force during the assembly of the crane to prevent turning of the guide member 70 due to the own weight.

Description

  The present invention relates to a crane having a backstop.

  Backstops that limit the range of rotation of crane booms and jibs are known. For example, in a crane in which a jib is pivotally attached to the tip of the boom, the boom is raised during work, and the tip of the backstop mounted on the boom side is supported by the target on the jib side. A crane is known in which a shaft is provided in parallel with a jib pivot pin (jib foot pin) in the vicinity of a set target, and a guide member is pivotally mounted on the shaft so that the guide member can be swung (non-patent). Reference 1).

Hitachi Sumitomo Heavy Industries Construction Crane Co., Ltd. Crawler Crane Instruction Manual MODEL 6000SLX BOOK NO. 2ZC-J-CO-00-003 SERIAL NO. 06000-7008 2010 p. 7-1- (11/62)

  In the crane described in the above-described document, a backstop is attached to the base end portion of the rear post. Therefore, when connecting the base end portion of the rear post to the tip of the boom (boom head), the guide member must support the other end of the backstop from below. However, in a state where the jib (jib base) is laid on the ground, the guide member has a posture different from the posture for supporting the other end of the backstop from below due to its own weight. Therefore, when connecting the base end portion of the rear post to the boom head, an assembly worker needs to hold the guide member from below the guide member in order to place the other end of the backstop on the guide member.

(1) A crane according to the invention of claim 1 includes a traveling body, an upper revolving body provided on the traveling body so as to be capable of swiveling, a boom whose base end is supported by the upper revolving body so as to be raised and lowered, and a tip of the boom. In a crane including a jib that is pivotally connected to the connecting portion and is raised and lowered with respect to the boom via a post, one end of the boom and the jib is pivotally supported on either side of the connecting portion. A backstop for limiting the relative angle between the boom and the jib within a predetermined range, and a backstop for limiting the relative angle within the predetermined range when the relative angle reaches a predetermined angle during crane operation. The other end of the abutment is abutted, and the abutting part provided on the other side of the boom and jib from the connecting part, and is pivotally supported by its own weight in the vicinity of the abutting part, and is backstop during crane work The other end of the Guide to the contact part and guide the other end of the backstop so that it does not contact the contact part when the crane is disassembled, allowing the relative angle to exceed the specified range. A guide member that supports and guides the guide member from below, and a mounting member that attaches a magnet that can be attracted to the guide member by magnetic force to either one of the boom and the jib from the connecting portion. A process in which the guide member is attracted by a magnetic force to prevent the guide member from rotating due to its own weight, and the guide member is guided by supporting the other end of the backstop from below with the magnet being prevented from rotating by its own weight. When a rotational force is applied by an external force received from the other end of the magnet, it rotates against the magnet's attractive force and is released from the magnet.
(2) A crane according to a second aspect of the invention includes a traveling body, an upper revolving body that is turnably provided on the traveling body, a boom whose base end is supported by the upper revolving body so as to be raised and lowered, and a distal end of the boom. In a crane including a jib that is pivotally connected and is raised and lowered with respect to the boom via a post, the boom and the post are connected to one side of the boom and the post rather than the connecting portion that rotatably connects the boom and the post. One end is pivotally supported so that the relative angle between the boom and the post is limited within a predetermined range. When the relative angle reaches a predetermined angle during crane operation, the relative angle is set within the predetermined range. The other end of the backstop abuts on the other side of the boom and post with respect to the connecting portion, and the shaft support is pivotable by its own weight in the vicinity of the abutting portion. Being clay The other end of the backstop is guided to the abutment part during work, and the other end of the backstop is guided not to abut the abutment part when disassembling the crane, allowing the relative angle to exceed the predetermined range. A guide member that supports and guides the other end of the backstop from below when assembling the crane, and a mounting member that attaches a magnet that can be attracted to the guide member by magnetic force to either the boom or the post rather than the connecting portion. The magnet is attracted to the guide member by a magnetic force when the crane is assembled to prevent the guide member from rotating due to its own weight, and the guide member is prevented from rotating by its own weight. In the process of supporting and guiding the end from below, when a rotational force is applied by an external force received from the other end, it rotates against the magnet's attractive force and is released from the magnet. To.
(3) The invention according to claim 3 is the crane according to claim 1 or 2, wherein the attachment member is a chain or a wire rope.

According to the present invention, the guide member is pivotally supported by its own weight in the vicinity of the abutting portion, and guides the other end of the backstop to the abutting portion during crane operation, and the backstop of the backstop when the crane is disassembled. The other end is guided so as not to contact the contact portion, and the other end of the backstop is supported and guided from below when the crane is assembled. Then, when the crane is assembled, the magnet attracts the guide member with magnetic force to prevent the guide member from rotating due to its own weight, and the guide member is prevented from rotating due to its own weight by the magnet. In the process of supporting and guiding the end from below, when a rotational force is applied by an external force received from the other end of the backstop, it is rotated against the attracting force of the magnet and released from the magnet. As a result, the other end of the backstop does not come into contact with the contact portion when the crane is disassembled, so that the crane can be easily disassembled.
Further, when the crane is assembled, the guide member is attracted by the magnet to prevent the guide member from rotating due to its own weight, and the other end of the backstop is supported and guided from below by the guide member. Thereby, the attitude | position of a guide member can be maintained so that the other end of a backstop can be supported and guided from the downward direction at the time of the assembly of a crane. Therefore, the operation of supporting the guide member from the lower side in order to keep the guide member in a predetermined posture at the time of assembling the crane is eliminated, and the crane assembling operation is facilitated.
In addition, when a rotational force acts on the guide member by an external force received from the other end in the process of supporting and guiding the other end of the backstop from below with the guide member, the guide member is rotated against the magnet's attracting force. It was configured to be released from the magnet. As a result, during the crane assembly operation, the other end of the backstop can be moved from below with the guide member even if the operator does not have to remove the magnet from the guide member after it is not necessary to prevent the guide member from rotating due to its own weight. The guide member is released from the magnet by an external force received from the other end in the process of supporting and guiding. Therefore, there is no possibility of damaging the guide member or the like.

It is an external appearance side view which shows the structure of the outline of a mobile crane. It is a side view of the vicinity of the top part (boom head) of a boom and the base end part (jib base) of a jib. It is a figure which shows a rear post, (a) is a side view, (b) and (c) are perspective views, (d) is the figure seen from the base end part side. It is a figure which shows the boom head and the vicinity of a jib base, (a) is a perspective view, (b) is the figure seen from the back surface, (c) is a side view. It is a side view of the vicinity of a target and a guide member. It is a perspective view of the vicinity of a target and a guide member. It is a figure explaining the attitude | position of the guide member at the time of making a boom and a jib fall on the ground. FIG. 5 is a side view showing the vicinity of the boom head and the jib base immediately after the base end portion of the rear post is connected to the boom head when the crane is assembled, and immediately before the base end portion of the rear post is removed from the boom head 30 when the crane is disassembled. It is a side view which shows the state which fixed the guide member with respect to the boom head via a magnet and a chain when connecting the base end part of a rear post to a boom head. The boom is raised by the progress of the assembly work of the crane, and the jib is inclined toward the front side relative to the boom, and the boom is lowered forward while the boom is being disassembled. It is a side view explaining the process which raises a jib relatively. The boom is raised by the progress of the assembly work of the crane, and the jib is inclined toward the front side relative to the boom, and the boom is lowered forward while the boom is being disassembled. It is a side view explaining the process which raises a jib relatively. The boom is raised by the progress of the assembly work of the crane, and the jib is inclined toward the front side relative to the boom, and the boom is lowered forward while the boom is being disassembled. It is a side view explaining the process which raises a jib relatively. The boom is raised by the progress of the assembly work of the crane, and the jib is inclined toward the front side relative to the boom, and the boom is lowered forward while the boom is being disassembled. It is a side view explaining the process which raises a jib relatively. It is a side view explaining a mode that a target and a guide member guide the other end of a back stop at the time of crane work. It is a side view explaining a mode that a target and a guide member guide the other end of a back stop at the time of crane work. It is a side view explaining a mode that a target and a guide member guide the other end of a back stop at the time of crane work.

  An embodiment of a crane according to the present invention will be described with reference to FIGS. FIG. 1 is an external side view showing a schematic configuration of a mobile crane according to the present embodiment. The mobile crane illustrated in FIG. 1 is a very large crane, and has a specification with a boom hanging hook. The mobile crane includes a traveling body 1, an upper swing body (swivel body) 2 that is rotatably mounted on the travel body, a boom 3 that is pivotally supported at the tip of the swing body 2, and a boom 3, a jib 4 pivotally supported at the distal end of 3, a jib hanging hook 5 suspended from the jib distal end (hereinafter referred to as a jib hook), and a boom hanging hook 6 suspended from the boom distal end. (Hereinafter referred to as a boom hook).

  A front drum 10, a rear drum 11, and a undulating drum 12 are mounted on the revolving body 2. A front wire rope 10a (hereinafter referred to as a front rope) is wound around the front drum 10, and the front rope 10a is connected to the boom hook 6 via a boom top. When the front drum 10 is driven, the front rope 10a is wound or unwound and the boom hook 6 is moved up and down. A rear wire rope 11a (hereinafter referred to as a rear rope) is wound around the rear drum 11, and the rear rope 11a is connected to the jib hook 5 via a boom top and a jib tip. As the rear drum 11 is driven, the rear rope 11a is wound or unwound and the jib hook 5 is raised and lowered.

  A mast 7 is pivotally supported at the front portion of the revolving structure 2, and the tip of the mast 7 and the top of the boom 3 are connected by a pendant rope 15. The hoisting drum 12 is wound with a hoisting wire rope 12a (hereinafter, hoisting rope), and the hoisting rope 12a is between a sheave 21 provided behind the hoisting drum 12 and a sheave 22 provided at the tip of the mast 7. It is hung multiple times. By driving the hoisting drum 12, the hoisting rope 12 a is wound or fed out to rotate the mast 7, and the boom 3 is hoisted via the pendant rope 15.

  An additional drum 13 which is an optional product is provided on the back side of the boom 3 (the right side in FIG. 1), and a wire rope 13a is wound around the additional drum 13. In FIG. 1, the left side surface of the boom 3 is referred to as the front surface. Similarly, in FIG. 1, the lower surface of the jib 4 is called a front surface, and the upper surface of the jib 4 is called a back surface. A front post 8 is attached to the base end of the jib 4, and the front post 8 and the jib tip are connected by a pendant 16. A rear post 9 is attached to the top of the boom 3, and the wire rope 13 a is wound around a plurality of times between sheaves 23, 24 provided at the tips of the posts 8, 9. By driving the additional drum 13, the wire rope 13 a is wound or fed out, the front post 8 is rotated with respect to the rear post 9, and the jib 4 is raised and lowered via the pendant 16.

  FIG. 2 is a side view of the vicinity of the top of the boom 3 (boom head 30) and the base end of the jib 4 (jib base 40). As shown in FIG. 2, the boom head 30 and the jib base 40 are rotatably connected by a jib foot pin 45. A backstop 50 is provided between the boom head 30 and the jib base 40. 3 is a view showing the rear post 9, FIG. 3 (a) is a side view, FIGS. 3 (b) and 3 (c) are perspective views, and FIG. 3 (d) is a view from the base end side. It is a figure. The backstop 50 is a member for limiting the rotation angle of the jib 4 with respect to the boom 30. As shown in FIG. 3, one end 51 is pivotally supported at the base end of the rear post 9 via a link 9 a. Has been. Since the base end of the rear post 9 is pivotally supported with respect to the boom head 30, one end 51 of the backstop 50 is attached to the boom head 30 via the rear post 9.

  Two backstops 50 are provided side by side in the lateral direction of the crane (the depth direction in FIG. 1, FIG. 2, FIG. 3A). The two left and right backstops 50 are connected to each other by a connecting member 53 (see FIG. 3C). At the other end 52 of the backstop 50, a roller 52a that is in contact with the guide member 70 and rotates when guided by a guide member 70 described later is attached. In FIG. 3, reference numeral 9 b denotes a shaft support portion at the base end portion of the rear post 9 that is supported by the shaft support portion 30 a (see FIG. 4) of the boom head 30.

  4 is a view showing the vicinity of the boom head 30 and the jib base 40, FIG. 4 (a) is a perspective view, FIG. 4 (b) is a view seen from the back, and FIG. 4 (c) is a side view. FIG. As shown in FIGS. 2 and 4, the jib base 40 is provided with a target (stopper portion) 60 with which the other end 52 of the backstop 50 abuts. Further, a guide member 70 is pivotally supported in the vicinity of the target 60 of the jib base 40 so as to be rotatable.

  As shown in FIG. 5, which is also an enlarged view of FIG. 4C, the target 60 includes a receiving portion 61 that receives the other end 52 by contacting the other end 52 of the backstop 50, and a jib 4 ( A guide portion 62 for guiding the other end 52 of the backstop 50 from the front side of the jib base 40) to the receiving portion 61 is provided. As shown in FIG. 4B, two targets 60 are provided, and are fixed to the jib base 40 in a state in which they are separated from each other in the left-right direction of the jib base 40. As will be described later, the target 60 is provided with a hole 60a for pivotally supporting the guide member 70 (see FIGS. 5 and 6). FIG. 6 is a perspective view of the vicinity of the target 60 and the guide member 70.

  As shown in FIGS. 5 and 6, the guide member 70 includes a first guide portion 71 that guides the other end 52 of the backstop 50 and guides the backstop 50 to a predetermined posture when the mobile crane is disassembled and assembled. A second guide portion 72 that guides the other end 52 to the receiving portion 61 of the target 60, a shaft 73, and a weight portion 74 when the mobile crane is operated. One guide member 70 is provided in the vicinity of each of the two targets 60. In a state where these two guide members 70 are connected to each other, a shaft 73 protruding in the depth direction in FIG. 5 is pivotally supported in a hole 60 a provided in the target 60.

  The guide member 70 maintains a predetermined absolute angle about the shaft 73 regardless of the undulation angle of the jib base 40 due to the weight of the weight portion 74. That is, the relative angle of the guide member 70 to the jib base 40 changes according to the undulation of the jib base 40. The range in which the relative angle of the guide member 70 with respect to the jib base 40 can be taken is limited by pins 63 and 64 (see FIGS. 4 and 6) attached to the target 60. Therefore, the guide member 70 maintains a predetermined absolute angle when the undulation angle (absolute angle) of the jib base 40 (that is, the jib 4) is within a predetermined range.

  The first guide portion 71 is a portion that supports and guides the other end 52 of the backstop 50 from the front side to the back side of the jib base 40. The second guide portion 72 is a portion that contacts and guides the roller 52a at the other end 52 of the backstop 50 from the back side of the jib base 40 toward the front side. The guidance of the other end 52 by the first guide part 71 and the second guide part 72 will be described later.

  A magnet 81 is attached to the boom head 30 via a chain 82. The magnet 81 is attracted to the guide member 70 when the mobile crane is assembled. Thereby, the guide member 70 is temporarily fixed to the boom head 30 via the magnet 81 and the chain 82 when the mobile crane is assembled. The fixing of the guide member 70 using the magnet 81 and the chain 82 will be described in detail later.

--- About the role of the guide member 70 in the assembly work ---
The mobile crane configured as described above is disassembled into parts and transported due to transportation restrictions. At this time, the boom 3 and the jib 4 are separated from the swing body 2. Then, after being brought into the work site, the disassembled crane is reassembled. At this time, the boom 3 and the jib 4 are attached to the revolving body 2 again. That is, when the disassembled crane is carried into the work site, the base end of the boom 3 is attached to the swing body 2, and the jib base 40 is rotatably connected to the boom head 30 by the jib foot pin 45. And the base end part of the rear post 9 is connected with the boom head 30 so that rotation is possible. The operation of connecting the base end portion of the rear post 9 to the boom head 30 is performed in a state in which the boom 3 and the jib 4 are tilted and faced down to the ground. Therefore, as it is, the attitude of the guide member 70 is as shown in FIG.

  As described above, the backstop 50 is attached to the proximal end portion of the rear post 9. Therefore, when the base end portion of the rear post 9 is connected to the boom head 30, the first guide portion 71 of the guide member 70 is normally connected to the other end 52 (roller 52 a) of the backstop 50 as shown in FIG. 8. Must be supported from below (from the front side to the back side of the jib base 40). That is, in a state where the jib 4 (jib base 40) is faced down to the ground, as shown in FIG. 7, the guide member 70 is a posture for the first guide portion 71 to support the other end 52 of the backstop 50 from below. Compared to (FIG. 8), the posture is rotated counterclockwise in the figure. As will be described later, this prevents the other end 52 of the backstop 50 from coming into contact with the receiving portion 61 of the target 60 so that the turning angle of the jib 4 with respect to the boom 3 is not limited when the mobile crane is disassembled. Because it is necessary to do.

  Therefore, in the present embodiment, after the jib base 40 is pivotably connected to the boom head 30 by the jib foot pin 45, the guide member 70 is moved against the gravity, for example, as shown in FIG. The magnet 81 is attracted to the weight portion 74 and the like after being rotated clockwise in the figure. By this operation, the guide member 70 is temporarily fixed to the boom head 30 through the magnet 81 and the chain 82 in the posture shown in FIG. That is, the magnet 81 and the chain 82 are for keeping the guide member 70 in a predetermined posture against gravity.

  Thereafter, when the shaft support portion 9b of the rear post 9 is connected to the shaft support portion 30a of the boom head 30, the roller 52a at the other end 52 of the backstop 50 is moved from below to the first guide portion 71 of the guide member 70 as shown in FIG. Supported by The length of the chain 82 is appropriately adjusted so that the magnet 81 can be fixed in the posture shown in FIG. 5 when the magnet 81 is attracted to the weight portion 74 or the like.

  Thereafter, the magnet 81 is removed from the guide member 70 by the worker's manual work. The magnet 81 removed from the guide member 70 may be appropriately attracted to an appropriate place such as the boom head 30 so that the chain 82 and the magnet 81 themselves do not swing. Even if the magnet 81 is removed from the guide member 70, the roller 52a presses the first guide portion 71 downward in the figure in the upper right of the figure in FIG. A rotating moment in the clockwise direction shown in the figure around 73 acts, and the guide member 70 maintains the posture shown in FIG. 9 against gravity. At this time, the guide member 70 abuts on the pin 64 (see FIGS. 4 and 6) of the target 60, so that the rotation of the guide member 70 about the shaft 73 in the clockwise direction is restricted.

  Although details are omitted, when the boom 3 is raised by the progress of the assembly work of the mobile crane thereafter and the jib 4 falls relative to the boom 3 toward the front side, as shown in FIG. The roller 52a rolls on the first guide portion 71 of the guide member 70, and the other end 52 of the backstop 50 moves to the left in the drawing (that is, the boom head 30 side).

  When the lowering of the jib 4 relative to the boom 3 toward the front side proceeds, the other end 52 of the backstop 50 further moves to the left in the drawing, and the roller 52a is positioned at the shaft 73 as shown in FIG. Rather than the upper left in FIG. As a result, a rotational moment in the counterclockwise direction around the shaft 73 acts on the guide member 70, so that the guide member 70 rotates in the counterclockwise direction around the shaft 73 as shown in FIG. . At this time, the guide member 70 abuts on the pin 63 (see FIGS. 4 and 6) of the target 60, so that the rotation of the guide member 70 about the shaft 73 in the counterclockwise direction is restricted. . Further, when the lowering of the jib 4 relative to the boom 3 toward the front side proceeds, the other end 52 of the backstop 50 is separated from the guide member 70 as shown in FIGS.

  Even if the magnet 81 is not removed from the guide member 70, if an external force received from the other end 52 of the backstop 50 causes a rotational moment in the counterclockwise direction around the shaft 73 to act on the guide member 70, The guide member 70 rotates against the attracting force of the magnet 81 and is released from the magnet 81.

--- About the role of the guide member 70 in crane work ---
In the state shown in FIG. 13, the boom 3 (boom head 30) is substantially upright to the standing angle in the crane work. Thereafter, when the jib 4 is raised, the target 60 and the guide member 70 approach the other end 52 of the backstop 50 as shown in FIG. As shown in FIGS. 13 to 15 sequentially, when the jib 4 (jib base 40) gradually rises and the jib 4 exceeds a predetermined ground angle, the guide member 70 is moved to the jib base 40 by the weight of the weight portion 74. Starts to rotate in the clockwise direction in the figure. Thus, during crane operation, the second guide portion 72 of the guide member 70 moves above the roller 52a so that the roller 52a at the other end 52 of the backstop 50 is guided to the receiving portion 61 of the target 60. 52 is guided. At this time, the guide part 62 of the target 60 guides the other end 52 from the lower side of the other end 52 to the receiving part 61. As a result, as shown in FIG. 16, the other end 52 of the backstop 50 is guided and brought into contact with the receiving portion 61 of the target 60, and the standing angle of the jib 4 (jib base 40) with respect to the boom 3 (boom head 30) is regulated. Is done.

--- About the role of the guide member 70 in the disassembly work ---
In the disassembling work of the crane, in order to remove the jib base 40 from the boom head 30, it is necessary to stand the boom 3 and the jib 4 on the ground by raising the jib 4 with respect to the boom 3 while the boom 3 is lying down. is there. Although detailed description is omitted, in the process of disassembling the crane, as shown in FIGS. 14 and 13, the jib 4 is once gradually lowered forward from the state shown in FIGS. 16 and 15. At this time, in the process of gradually lowering the jib 4 (jib base 40), the other end 52 of the backstop 50 is separated from the receiving part 61 of the target 60, contrary to the case where the jib 4 is raised. The member 70 rotates in the illustrated counterclockwise direction relative to the jib base 40 by the weight of the weight portion 74. Then, when the guide member 70 abuts on the pin 63 (see FIGS. 4 and 6) of the target 60, the rotation of the guide member 70 around the shaft 73 in the counterclockwise direction is restricted (FIG. 13). .

  After the jib 4 is laid down forward, the jib 4 is erected with respect to the boom 3 so that the tip of the jib 4 does not interfere with the ground in order to lie down the boom 3 forward (FIG. 12). Thereby, the other end 52 of the backstop 50 approaches the target 60. However, in the process of disassembling the crane, even if the other end 52 of the backstop 50 approaches the target 60, the guide member 70 is relative to the jib base 40 by the weight of the weight portion 74 as shown in FIG. It remains rotating counterclockwise in the figure. Therefore, the first guide portion 71 of the guide member 70 comes into contact with the roller 52a at the other end 52 of the backstop 50 obliquely below in the drawing.

  Thereafter, when the jib 4 is raised with respect to the boom 3 while further lowering the boom 3 forward, the roller 52a at the other end 52 of the backstop 50 is moved toward the guide member 70 as shown in FIGS. 1 It moves on the guide part 71, rolling toward the left in the figure. Thereafter, the base end portion of the rear post 9 is removed from the boom head 30, and the jib base 40 is removed from the boom head 30.

The mobile crane of the present embodiment has the following effects.
(1) The guide member 70 is pivotally supported by its own weight in the vicinity of the receiving portion 61 that is a contact portion of the target 60, and guides the other end 52 of the backstop 50 to the receiving portion 61 during crane operation. The other end 52 of the backstop 50 is guided so as not to contact the receiving portion 61 when the crane is disassembled, and the other end 52 of the backstop 50 is supported and guided from below when the crane is assembled. The magnet 81 attracts the guide member 70 with magnetic force when the crane is assembled to prevent the guide member 70 from rotating due to its own weight, and the guide member 70 is prevented from rotating due to its own weight by the magnet 81. In the process of supporting and guiding the other end 52 of the backstop 50 from below, when a rotational force is exerted by an external force received from the other end 52 of the backstop 50, it rotates against the attracting force of the magnet 81 and rotates from the magnet 81. Configured to be released. Thereby, since the other end 52 of the backstop 50 does not contact the receiving portion 61 when the crane is disassembled, the disassembling work of the crane is facilitated.

(2) When the crane is assembled, the guide member 70 is attracted by the magnet 81 to prevent the guide member 70 from rotating due to its own weight, and the other end 52 of the backstop 50 is supported by the guide member 70 from below and guided. Configured. Thereby, the attitude | position of the guide member 70 can be maintained so that the other end 52 of the backstop 50 can be supported and guided from below when assembling the crane. Therefore, the operation of supporting the guide member 70 from below to maintain the posture of the guide member 70 so that the other end 52 of the backstop 50 can be supported and guided from below when the crane is assembled can be eliminated, and the crane can be easily assembled. Become.

(3) When a rotational force acts on the guide member 70 by an external force received from the other end 52 (roller 52a) in the process of supporting and guiding the other end 52 of the backstop 50 from below with the guide member 70, the attracting force of the magnet 81 The guide member 70 is configured to be released from the magnet 81 by rotating against the magnet. This eliminates the need for the magnet 81 to prevent the guide member 70 from rotating due to its own weight during the crane assembling work, so that the operator does not have to remove the magnet 81 from the guide member 70, so The guide member 70 is released from the magnet 81 by an external force received from the other end 52 in the process of supporting and guiding the end 52 from below with the guide member 70. Therefore, there is no possibility of damaging the guide member 70 and the like.

(4) The magnet 81 is used to prevent the guide member 70 from rotating due to its own weight when the crane is assembled. Thereby, since the magnet 81 can be used repeatedly, it is economical.

  In the above description, the magnet 81 is attached to the boom head 30 via the chain 82, but the present invention is not limited to this. For example, instead of the chain 82, a wire rope, a string, a link configured to be bent in the middle, a bar-like member that is not bent in the middle but is simply pivotally supported at the end portion, and the like may be used.

  In the above description, one end 51 of the backstop 50 is attached to the boom head 30 side, and the target 60 and the guide member 70 are provided on the jib base 40. However, the present invention is not limited to this. For example, one end 51 of the backstop 50 may be attached to the jib base 40 side, and the target 60 and the guide member 70 may be provided on the boom head 30 side. In this case, the magnet 81 may be attached to the jib base 40 side via the chain 82.

  In the above description, the backstop 50 that regulates the relative angle between the boom 3 and the jib 4 has been described, but the present invention is not limited to this. For example, the present invention may be applied to a backstop that regulates the relative angle between the boom 3 and the rear post 9. In other words, one end of the mobile crane is pivotally supported at one side of the boom 3 and the rear post 9 relative to the pivotal support portion 30a of the boom head 30 that rotatably connects the boom 3 and the rear post 9. A backstop 50 for limiting the relative angle between the boom 3 and the rear post 9 within a predetermined range, and for limiting the relative angle within a predetermined range when the relative angle reaches a predetermined angle during crane operation. The other end 52 of the backstop 50 comes into contact with the target 60 provided on the other side of the boom 3 and the rear post 9 with respect to the shaft support 30a, and is pivotally supported by its own weight in the vicinity of the target 60. The other end 52 of the backstop 50 is guided to the target 60 when the crane is operated, and the other end 52 of the backstop 50 is turned on when the crane is disassembled. A guide member 70 that guides so as not to contact the get 60 and allows the relative angle to exceed a predetermined range, and supports and guides the other end 52 of the backstop 50 from below when assembling the crane; A magnet 81 that can be attracted to the member 70 by magnetic force is provided with a chain 82 that is attached to either the boom 3 or the rear post 9 relative to the shaft support 30a. The magnet 81 is a guide member 70 when the crane is assembled. And the guide member 70 supports and guides the other end 52 of the backstop 50 from below with the magnet 81 preventing rotation by its own weight. In the process, when a rotational force is applied by an external force received from the other end 52, it rotates against the attracting force of the magnet 81 and rotates. It may be configured to be released from the net 81. Moreover, you may combine each embodiment and modification which were mentioned above, respectively.

In addition, this invention is not limited to the thing of embodiment mentioned above at all, A base body is supported so that raising / lowering can be carried out to a traveling body, the upper revolving body provided on a traveling body so that turning is possible, and an upper revolving body. In a crane including a boom and a jib that is pivotally connected to a connecting portion at a tip of the boom and is raised and lowered with respect to the boom via a post, one end of the boom and the jib is connected to one end of the boom and the jib from the connecting portion. Is pivotally supported to limit the relative angle between the boom and jib within a predetermined range, and when the relative angle reaches a predetermined angle during crane operation, the relative angle is within the predetermined range. The other end of the backstop abuts on the other end of the boom and the jib from the connecting part, and is pivotally supported by its own weight in the vicinity of the abutting part. When the crane is working, Assemble the other end of the stop to the abutment part and guide the other end of the backstop not to abut the abutment part when disassembling the crane, allowing the relative angle to exceed the specified range, and assembling the crane A guide member that sometimes supports and guides the other end of the backstop from below, and a mounting member that attaches a magnet that can be attracted to the guide member by a magnetic force to either the boom or the jib from the connecting portion. When the crane is assembled, the guide member is attracted by the magnetic force to prevent the guide member from rotating due to its own weight, and the guide member is prevented from rotating by its own weight by the magnet, and the other end of the backstop is viewed from below. Various structures characterized in that when a rotational force is applied by an external force received from the other end in the process of supporting and guiding, it rotates against the magnet's attractive force and is released from the magnet It is intended to include the crane.
Further, the present invention is not limited to the above-described embodiment, and the traveling body, the upper revolving body that is turnably provided on the traveling body, and the base end of the upper revolving body are supported to be raised and lowered. In a crane including a boom and a jib that is pivotally connected to the tip of the boom and is raised and lowered with respect to the boom via a post, the boom and the link are connected to the boom and the post in a rotatable manner. One end of the post is pivotally supported so that the relative angle between the boom and the post is limited within a predetermined range, and when the relative angle reaches a predetermined angle during crane work In order to limit the relative angle within a predetermined range, the other end of the backstop abuts, the abutting portion provided on the other side of the boom and the post from the connecting portion, and the weight of the abutting portion in the vicinity of the abutting portion. Can be rotated by The other end of the backstop is guided to the abutting portion when the crane is operated, and the other end of the backstop is guided not to abut against the abutting portion when the crane is disassembled. A guide member that supports and guides the other end of the backstop from below when assembling the crane, and a magnet that can be attracted to the guide member by magnetic force on either the boom or post side of the connection part The magnet is attracted to the guide member by a magnetic force when the crane is assembled to prevent the guide member from rotating due to its own weight, and the guide member is prevented from rotating due to its own weight by the magnet. In the process of supporting and guiding the other end of the backstop from below, when a rotational force is applied by an external force received from the other end, it rotates against the attracting force of the magnet It is intended to include crane various structures characterized in that it is released.

3 Boom 4 Jib 9 Rear post 30 Boom head 40 Jib base 45 Jib foot pin 50 Back stop 52 Other end 60 Target (stopper part) 61 Receiving part 70 Guide member 71 First guide part 72 Second guide part 73 Shaft 74 Weight part 81 Magnet 82 Chain

Claims (3)

A traveling body,
An upper revolving structure provided on the traveling body so as to be capable of revolving;
A boom whose base end is supported by the upper swing body so as to be raised and lowered;
In a crane comprising a jib pivotably connected to a connecting portion at the tip of the boom and raised and lowered with respect to the boom via a post,
A backstop that is pivotally supported at one end of the boom and the jib relative to the connecting portion so as to be rotatable, and limits a relative angle formed by the boom and the jib within a predetermined range;
When the relative angle reaches a predetermined angle during crane operation, the other end of the backstop comes into contact to limit the relative angle within the predetermined range. Or a contact portion provided on the other side,
It is pivotally supported by its own weight in the vicinity of the abutment portion, guides the other end of the backstop to the abutment portion during crane operation, and the other end of the backstop is disassembled when the crane is disassembled. A guide member that guides so as not to come into contact with the contact portion, allows the relative angle to exceed the predetermined range, and supports and guides the other end of the backstop from below when the crane is assembled. When,
An attachment member that attaches a magnet that can be attracted to the guide member by magnetic force to either the boom or the jib from the connection portion;
The magnet is attracted by the magnetic force to the guide member during assembly of the crane to prevent rotation due to its own weight,
In the state where the guide member is prevented from rotating due to its own weight by the magnet, when the rotational force acts by the external force received from the other end in the process of supporting and guiding the other end of the backstop from below, the magnet A crane that rotates against the attracting force of the magnet and is released from the magnet. A traveling body,
An upper revolving structure provided on the traveling body so as to be capable of revolving;
A boom whose base end is supported by the upper swing body so as to be raised and lowered;
In a crane comprising a jib pivotably connected to the tip of the boom and raised and lowered with respect to the boom via a post,
One end of the boom and the post is pivotally supported on one side of the boom and the post so that the boom and the post are rotatably connected, and a relative angle formed by the boom and the post is determined. A backstop limited to a predetermined range;
When the relative angle reaches a predetermined angle during crane operation, the other end of the backstop comes into contact to limit the relative angle within the predetermined range. Or a contact portion provided on the other side,
It is pivotally supported by its own weight in the vicinity of the abutment portion, guides the other end of the backstop to the abutment portion during crane operation, and the other end of the backstop is disassembled when the crane is disassembled. A guide member that guides so as not to come into contact with the contact portion, allows the relative angle to exceed the predetermined range, and supports and guides the other end of the backstop from below when the crane is assembled. When,
A mounting member that attaches a magnet that can be attracted to the guide member by magnetic force to either the boom or the post from the connecting portion;
The magnet is attracted by the magnetic force to the guide member during assembly of the crane to prevent rotation due to its own weight,
In the state where the guide member is prevented from rotating due to its own weight by the magnet, when the rotational force acts by the external force received from the other end in the process of supporting and guiding the other end of the backstop from below, the magnet A crane that rotates against the attracting force of the magnet and is released from the magnet. The crane according to claim 1 or 2,
The crane, wherein the attachment member is a chain or a wire rope.

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