1. Field of the Invention
The present invention relates to a crane, and a crane assembling method.
2. Background Art
Heretofore, there has been known a crane which comprises: a boom; a luffing jib (hereinafter referred to simply as “jib”) attached to the boom in a raisable and lowerable manner; and a strut attached to the boom in a raisable and lowerable manner, to raise and lower the jib. This type of crane is disclosed, for example, in JP 2004-75294A, JP 4613897B and JP 04-033717B.
A method of attaching a jib to a boom includes an extending-type attaching method and an enfolding-type attaching method. In the extending-type attaching method, a jib is laid in front of a boom which is lowered and laid down, and, in this state, the jib is attached to the boom, as described, for example, in FIGS. 1 to 4 of the JP 2004-75294A. In the enfolding-type attaching method, a jib is laid under a boom which is lowered and laid down, and hoisted up, and, in this state, the jib is attached to the boom, as described, for example, in FIGS. 9 and 10 of the JP 4613897B. As compared to the enfolding-type attaching method, the extending-type attaching method facilitates assembling of a jib, although there is a need for a larger assembling space. As compared to the extending-type attaching method, the enfolding-type attaching method has more difficulty in performing an operation of attaching a jib to a boom. That is, in the enfolding-type attaching method, assemblability of a jib becomes poor. On the other hand, the enfolding-type attaching method needs less assembling space. Meanwhile, the enfolding-type attaching method includes an enfolding support-type attaching method described on FIGS. 3 to 7 of the JP 04-033717B, and a jib foot offset-type attaching method in which a jib foot is disposed at a position largely offset from a central axis of a boom.
A method of attaching a strut and a jib to a boom includes the following two processes. One is a process I in which the strut is attached to the boom, and then the jib is attached to the boom, and the other is a process II in which the jib is attached to the boom, and then the strut is attached to the boom. In the case where the process I is employed in the extending-type attaching method, an operation of attaching the jib to the boom has to be performed under the strut, so that assemblability of the jib becomes poor. In the case where the process I is employed in the enfolding-type attaching method, when the boom is positionally adjusted with respect to the jib placed on the ground (see, for example, FIG. 8 of the JP 4613897B), the boom has to be turned in a state in which the strut is attached thereto, so that it needs to take a long time for the position adjustment. As a result, assemblability of the jib becomes poor. On the other hand, in the case where the process II is employed in the extending-type attaching method, after attaching the jib to the boom, the strut is assembled above the jib, so that an assembling operation of the strut at a distal end of the boom has to be performed in high places, and thereby assemblability of the strut becomes poor. In the case where the process II is employed in the enfolding-type attaching method, a head of the boom cannot be placed in contact with the ground, so that the assembling operation of the strut at the distal end of the boom has to be performed in higher places, and thereby assemblability of the strut becomes poor.
As above, various methods have been employed in conventional cranes to attach a jib and a strut to a boom. However, each of the attaching methods has a problem with assemblability of the jib or strut.
It is an object of the present invention to improve assemblability of a jib and a strut of a crane.
According to one aspect of the present invention, there is provided a crane which comprises: a crane body; a boom attached to the crane body in a raisable and lowerable manner; a luffing jib attached to a head of the boom in a raisable and lowerable manner; and a strut attached to the head of the boom in a raisable and lowerable manner, to raise and lower the luffing jib. The luffing jib comprises: a lower jib making up a first portion of the luffing jib, the first portion extending over a specific range from a base end of the luffing jib toward a tip of the luffing jib, wherein the lower jib is attached to the head of the boom in a raisable and lowerable manner, at a position located below an attaching position of a base end of the strut to the head of the boom in a state in which the boom is lowered and laid down; and an upper jib making up a second portion of the luffing jib, the second portion positioned between the tip of the luffing jib and the lower jib, wherein the upper jib is coupled to the lower jib in such a manner as to be separable from the lower jib. The lower jib is attached to the head of the boom to have a laid-down posture at a position at a position between the boom and the strut when the upper jib is separated from the lower jib, when the boom is lowered and laid down to allow the head of the boom to come into contact with the ground and when the strut is lowered and laid down to allow a distal end of the strut to come into contact with the ground. The lower jib has a length which causes no interference with the strut when the lower jib has the laid-down posture at the position between the boom and the strut.
With reference to
As illustrated in
The crane body 5 comprises a lower body 5a and an upper slewing body 5b attached to the lower body 5a in a slewable manner, and is provided with a reeving winch 7. For example, the lower body 5a may be a self-propelled type, i.e., a lower propelling body. In this case, the lower body 5a may be a crawler type, or may be a wheel type.
The reeving winch 7 is a winch for winding and unwinding a reeving rope R4. The reeving winch 7 is attached to the crane body 5. Specifically, the reeving winch 7 is attached to a front end of the crane body 5, for example, a front end of the upper slewing body 5b. Alternatively, the reeving winch 7 may be attached to a front end of the lower body 5a. The reeving rope R4 is a rope for assisting in wrapping a wire rope (not illustrated) or the like for suspending a load from the boom 10 and/or a jib 30, around the boom 10 and others. The reeving rope R4 has a diameter smaller than a diameter of the wire rope, and is easy to handle.
The boom 10 is attached to the crane body 5 in a raisable and lowerable manner. For example, the boom 10 may be a rod-type structural body having a lattice structure, i.e., a lattice boom. For example, each of the strut 20 and the jib 30 may be a rod-type structural body having a lattice structure, as with the boom 10. In the following description, as illustrated in
The boom 10 is an assembling type, and configured to be disassembleable into a plurality of members in the boom axis direction Xb. The boom 10 comprises a lower boom 10a, an intermediate boom 10b, and a top boom 10c. The lower boom 10a, the intermediate boom 10b and the top boom 10c are arranged side-by-side in this order along a direction from the boom base end side Xb1 to the boom tip side Xb2. The intermediate boom 10b is configured to be able to be disassembled into a plurality of members in the boom axis direction Xb. Alternatively, the intermediate boom 10b may be configured to be unable to be disassembled into a plurality of members in the boom axis direction Xb. A head (tip portion) of the boom 10 will hereinafter be referred to as “boom head 10t”.
As illustrated in
As illustrated in
The strut mounting portion 13 comprises a front strut mounting portion 13f, and a rear strut mounting portion 13r disposed farther toward the boom back side Yb1 than the front strut mounting portion 13f.
Each of the boom-side jib foot 15f and the boom-side support portion 15s are formed in a U-shaped groove. The boom-side jib foot 15f is disposed farther toward the boom belly side Yb2 than the strut mounting portion 13. The boom-side support portion 15s is disposed farther toward the boom belly side Yb2 than the boom-side jib foot 15f.
The inner link mounting bracket 17i has a pin hole. The inner link mounting bracket 17i is provided in the boom head frame 11 in such a manner that the pin hole of the inner link mounting bracket 17i is disposed in coaxial relation with the boom-side jib foot 15f. The outer link mounting bracket 17o has a pin hole. The outer link mounting bracket 17o is provided in the boom head frame 11 in such a manner that the pin hole of the outer link mounting bracket 17o is disposed in coaxial relation with the boom-side support portion 15s.
The boom head support portion 19 is configured to be grounded, i.e., to be brought into contact with a ground surface G, when the boom 10 is fully lowered and laid down. The boom head support portion 19 is fixed to the boom head frame 11 in such a manner as to protrude from the boom head frame 11 toward the boom belly side Yb2 (see
The strut 20 (see
As illustrated in
The strut support portion 29 is configured to be grounded when the boom 10 is lowered and laid down, and the front strut 20f is fully lowered and laid down. The strut support portion 29 is disposed to protrude from a body of the front strut 20f formed as a rod-type structural body, toward a belly side of the front strut 20f (an under side of the front strut 20f in the laid down posture).
The jib (luffing jib) 30 (see
The jib 30 is an assembling type, and configured to be able to be divided into a plurality of members in the jib axis direction Xj. The jib 30 comprises an upper jib 31, and a lower jib 40.
The upper jib 31 is coupled to an end of the lower jib 40 on the jib tip side Xj2, in such a manner as to be separable with respect to the lower jib 40. The upper jib 31 is configured to be able to be divided into a plurality of members in the jib axis direction Xj. For example, the upper jib 31 comprises a top jib 31a, an intermediate jib 31b and an intermediate tapered jib 31c. The top jib 31a, the intermediate jib 31b and the intermediate tapered jib 31c are arranged side-by-side in this order along a direction from the jib tip side Xj2 to the jib base end side Xj1.
As illustrated in
The upper jib frame 33 is composed of a plurality of pipes. Specifically, the upper jib frame 33 comprises four main members 33a, two base-end lateral members 33b, and two base-end perpendicular members 33c. Each of the main members 33a is disposed at a respective one of four corners of a quadrangular cross-section of the upper jib frame 33, when viewed in the jib axis direction Xj. The base-end lateral members 33b and the base-end perpendicular members 33c are arranged at an end of the upper jib frame 33 on the jib base end side Xj1. Each of the base-end lateral members 33b is disposed to extend in the jib lateral direction Zj. Each of the base-end perpendicular members 33c is disposed to extend in the jib up-down direction Yj.
The upper-side connector 35 is configured to be joined to an aftermentioned lower-side connector 50 of the lower jib 40, thereby allowing the intermediate tapered jib 31c of the upper jib 31 and the lower jib 40 to be coupled together. The upper-side connector 35 is fixed to each end of the four main members 33a on the jib base end side Xj1, that is, the upper-side connector 35 is provided in a number of four, wherein the four upper-side connectors 35 are fixed, respectively, to four ends of the main members 33a on the jib base end side Xj1. As illustrated in
The guide bracket 37 is configured to facilitate a position adjustment between the pin hole 35b of the upper-side connector 35 and a pin hole 50b of the aftermentioned lower-side connector 50. In other words, the guide bracket 37 is configured to guide the aftermentioned lower-side connector 50 and the upper-side connector 35 to a specific relative position where positions of the pin holes 50b, 35b of the lower-side and upper-side connectors 50, 35 are aligned with each other. As illustrated in
The lateral-member guide member 37b is a portion for performing a position adjustment between the pin hole 35b and the pin hole 50b in the jib up-down direction Yj. The lateral-member guide member 37b is fixed to the base-end lateral member 33b to extend from the base-end lateral member 33b toward the jib base end side Xj1. As illustrated in
The perpendicular-member guide member 37c is a portion for performing a position adjustment between the pin hole 35b and the pin hole 50b in the jib axis direction Xj. The perpendicular-member guide member 37c is fixed to the lateral-member guide member 37b to extend outwardly from the lateral-member guide member 37b in the jib lateral direction Zj. Alternatively, the perpendicular-member guide member 37c may be provided as a separate member separated from the lateral-member guide member 37b. The perpendicular-member guide member 37c is configured to be brought into contact with an aftermentioned distal-end perpendicular member 41c in the jib axis direction Xj when the position of the pin hole 35b and the position of the pin hole 50b are aligned with each other (in the “state A”). Specifically, the perpendicular-member guide member 37c is configured such that, in the “state A”, an end thereof on the jib base end side Xj1 is brought into contact with the aftermentioned distal-end perpendicular member 41c, in opposed relation thereto in the jib axis direction Xj. The perpendicular-member guide member 37c has a stepped portion 37e. The stepped portion 37e is formed to be brought into contact with the aftermentioned distal-end perpendicular member 41c in the “state A”. The stepped portion 37e is formed to extend approximately along the aftermentioned distal-end perpendicular member 41c in the “state A”.
As illustrated in
As illustrated in
The lower jib frame 41 is one example of a “frame” set forth in the appended claims. The lower jib frame 41 is, as it were, a body of the lower jib 40, and formed in an approximately triangle pillar shape. The lower jib frame 41 is formed using a pipe, a plate, etc. to extend from the jib-side jib foot 43f to a distal end of the lower jib 40. Specifically, the lower jib frame 41 comprises four main members 41a, two distal-end lateral members 41b, and two distal-end perpendicular members 41c. Each of the main members 41a is disposed at a respective one of four corners of a quadrangular cross-section of the lower jib frame 41, when viewed in the jib axis direction Xj. The distal-end lateral members 41b and the distal-end perpendicular members 41c are arranged at an end of the lower jib frame 41 on the jib tip side Xj2, i.e., at an end of the lower jib frame 41 to which the intermediate tapered jib 31c is coupled. Each of the distal-end lateral members 41b is disposed to extend in the jib lateral direction Zj (in the lateral direction of the jib 30). Each of the distal-end perpendicular members 41c is disposed to extend in the jib up-down direction Yj (in the direction perpendicular to the lateral and axial directions of the jib 30).
The jib-side jib foot 43f (see
The jib-side support portion 43s serves as a pivot shaft of the jib 30 when the jib 30 is rotated with respect to the boom 10, in order to perform an operation, for example, of attaching the upper jib 31 to the lower jib 40 in an enfolded state of the jib 30, as illustrated in
The enfolding link mechanism 45 is a mechanism for coupling the lower jib 40 and the boom head 10t. As illustrated in
The inner links 47 are provided, respectively, at two positions inward of respective pairs of the main members 41a of the lower jib frame 41 located on opposite sides in the jib lateral direction Zj. As illustrated in
As illustrated in
The lower-side connector 50 (see
The roller unit 60 is a unit comprising an aftermentioned roller 65, etc., as illustrated in
The roller 65 is configured, under a condition where the upper jib 31 is separated from the lower jib 40, to be rollingly movable with respect to the ground surface G, while supporting, with respect to the ground surface G, an end of the lower jib 40 on a side opposite to the boom head 10t. As illustrated in
The roller shaft 67 is a rotation shaft of the roller 65. Under the condition where the upper jib 31 is separated from the lower jib 40, the roller shaft 67 is inserted into the pin hole 50b of the lower-side connector 50 as illustrated in
The roller shaft 67 may be formed to be additionally usable as the pin P for coupling the upper-side connector 35 and the lower-side connector 50 together, illustrated in
<Crane Assembling Method>
A crane assembling method according to this embodiment will be described below approximately according to a sequence of steps. It should be noted that a sequence of aftermentioned steps may be arbitrarily changed. The crane assembling method comprises a preparation step, a boom attaching step, a jib attaching and assembling step, and a strut attaching step.
[Preparation Step]
In the preparation step, the crane body 5 is prepared and provided with the reeving winch 7.
[Boom Attaching Step]
In the boom attaching step, the boom 10 is attached to the upper slewing body 5b of the crane body 5.
[Jib Attaching and Assembling Step]
In the jib attaching and assembling step, the jib 30 is attached to the boom head 10t, and the jib 30 is assembled. In this embodiment, the strut attaching step is performed during a course of the jib attaching and assembling step. The jib attaching and assembling step comprises a lower jib attaching substep, a lower jib turning-over substep, and an upper jib coupling substep.
(Lower Jib Attaching Substep)
In the lower jib attaching substep, as illustrated in 7A, the lower jib 40 is joined to the boom head 10t from a front side (which will be defined later) of the laid-down boom 10. This substep is performed as follows.
(1a) The boom 10 is lowered and laid down, and the boom head support portion 19 is grounded. In this embodiment, a side beyond the boom head 10t in a direction toward the boom tip side Xb2 will hereinafter be referred to as “front side” of the laid-down boom 10.
(1b) The lower jib 40 is hoisted up by an auxiliary crane other than the crane 1.
(1c) The jib-side jib foot 43f is fitted into the boom-side jib foot 15f from the front side of the laid-down boom 10. This fitting operation is easier than that in the conventional enfolding-type attaching method, i.e., an operation of fitting jib-side jib foot 43f into the boom-side jib foot 15f from below the laid-down boom 10.
(1d) The distal end 47t of the inner link 47 is attached to the inner link mounting bracket 17i through a pin (not illustrated).
(1e) As illustrated in
(1f) The distal end 49t of the outer link 49 is attached to the outer link mounting bracket 17o through a pin (not illustrated).
In the above way, before attaching the strut 20 (see
[Strut Attaching Step]
In the strut attaching step, the strut 20 is attached to the boom head 10t, as illustrated in
(2a) The front strut 20f is attached to the front strut mounting portion 13f. During this operation, the lower jib 40 is disposed on the front side of the laid-down boom 10. Thus, the boom head support portion 19 can be grounded. Assuming that the lower jib 40 is turned over as illustrated in
(2b) As illustrated in
(2c) As illustrated in
(2d) As illustrated in
(2e) As illustrated in
(Lower Jib Turning-over Substep)
In the lower jib turning-over substep, as illustrated in
(3a) The boom 10 illustrated in
(3b) As illustrated in
(3c) When the boom 10 is further raised, the lower jib 40 rotates about the boom-side support portion 15s.
(3d) As a result, as illustrated in
(3e) When the gravity center 40g of the lower jib 40 reaches the position just below the boom-side support portion 15s, an angle θ defined between the central axis of the lower jib 40 and the ground surface G (horizontal direction) is at least less than 90 degrees, preferably, equal to or less than 60 degrees, 45 degrees or 30 degrees.
(3f) Then, when the boom 10 is lowered to allow the lower jib 40 to be grounded, the lower jib 40 is further rotated.
(3g) The boom head 10t and the lower jib 40 are coupled together by a coupling rope R3. This restricts a rotation of the lower jib 40 with respect to the boom 10. Thus, it becomes possible to restrict an inclination of the lower jib 40 with respect to the upper jib 31, when the upper jib 31 is connected to the lower jib 40 illustrated in
(3h) As illustrated in
(Upper Jib Coupling Substep)
In the upper jib coupling substep, as illustrated in
The arranging sub-substep is configured to set a position of the upper jib 31 with respect to the boom 10, before coupling the upper jib 31 to the lower jib 40. In the arranging sub-substep, the upper jib 31 is placed on the ground surface G, and then the upper slewing body 5b (see
In the upper jib lifting sub-substep, as illustrated in
The rope connecting sub-substep is configured to connect a reeving rope R4 to the intermediate tapered jib 31c of the upper jib 31. Specifically, in the rope connecting sub-substep, the following operations (a) to (c) are performed in this order.
(a) The reeving rope R4 is pulled out from the reeving winch 7 in a direction from the boom base end side Xb1 to the boom tip side Xb2. The reeving rope R4 pulled out from the reeving winch 7 is pulled out toward the boom head 10t as illustrated in
(b) The reeving rope R4 pulled out as described in the operation (a) is turned back toward the boom base end side Xb1 at a position frontward of an attaching position of the reeving rope R4 to the intermediate tapered jib 31c (at a position on the jib base end side Xj1). Specifically, the reeving rope R4 is wrapped around a sheave provided on the boom head 10t in such a manner as to be turned back toward the boom base end side Xb1.
(c) A distal end of the reeving rope R4 turned back as described in the operation (b) is connected (fixed) to the intermediate tapered jib 31c. The distal end of the reeving rope R4 is connected, for example, to an upper region of an end of the intermediate tapered jib 31c on the jib base end side Xj1, i.e., a portion of an end of the intermediate tapered jib 31c on the jib base end side Xj1 and on the jib belly side Yj2.
In the rope winding sub-substep, the reeving rope R4 is wound by the reeving winch 7 (see
Details of the position adjustment are described as the following operations (d) to (e).
(d) As illustrated in 10A and 11A, an upper end of the lateral-member guide member 37b is brought into contact with a lower end of the distal-end lateral member 41b. That is, the upper end of the lateral-member guide member 37b supports the lower end of the distal-end lateral member 41b, from therebelow. Thus, a position adjustment between the pin hole 35b and each of the pin holes 50b in the jib up-down direction Yj is performed. In other words, the upper-side connector 35 is guided to a specific engagement position (relative position) where positions of the pin hole 35b and the pin hole 50b are aligned with each other in the jib up-down direction Yj. During this operation, as illustrated in
(e) As illustrated in
In the pin inserting sub-substep (connector coupling sub-substep), under a condition where the lower-side connector 50 and the upper-side connector 35 are engaged with each other, the pin P is inserted into the pin hole 35b and the pin holes 50b, as illustrated in
In the above manner, the jib 30 is assembled under the boom 10. This makes it possible to suppress an assembling space for the crane 1, as compared to the case where the jib 30 is assembled only in front of the laid-down boom 10 as in assembling based on the conventional extending-type attaching method.
[Advantageous Effects]
Effects obtainable by the configuration of the crane 1 according to the above embodiment will be described below.
(Effect 1)
The crane 1 comprises: the crane body 5; the boom 10 attached to the crane body 5; the jib 30 attached to the boom head 10t; and the strut 20 attached to the boom head 10t to raise and lower the jib 20. As illustrated in
The lower jib 40 formed in the above manner has a length in the jib axis direction Xj, which is less than that of the conventional lower jib. Therefore, it is easy to perform a position adjustment of the lower jib 40 with respect to the boom head l Ot. Thus, it is easy to attach the lower jib 40 to the boom head 10t. As a result, it becomes possible to improve assemblability of the jib 30 (see
As illustrated in
The lower jib 40 has a length less than that of the conventional lower jib. Therefore, it become possible to easily cause the lower jib 40 to rotate with respect to the boom head 10t (see
(a) As illustrated in
(b) As illustrated in 8A to 8C, the lower jib 40 is turned over with respect to the boom head 10t.
(c) As illustrated in
(Effect 2)
As illustrated in
This roller 65 allows the distal end of the lower jib 40 to be easily slidingly moved with respect to the ground surface G. Thus, it becomes possible to further facilitate turning-over of the lower jib 40 with respect to the boom head 10t.
(Effect 3)
As illustrated in
This configuration eliminates a need for the lower jib 40 illustrated in
(Effect 4)
The guide bracket 37 illustrated in
In this configuration, the position adjustment between the pin hole 50b and the pin hole 35b in the jib up-down direction Yj can be performed only by placing the distal-end lateral member 41b on the lateral-member guide member 37b. Thus, it becomes possible to improve efficiency of the operation of coupling the lower jib 40 and the intermediate tapered jib 31c of the upper jib 31.
(Effect 5)
The lower jib 40 comprises the distal-end perpendicular member 41c constituting the end of the lower jib 40 to be coupled to the intermediate tapered jib 31c of the upper jib 31, i.e., the end of the lower jib 40 on the jib tip side Xj2. As illustrated in
In this configuration, the position adjustment between the pin hole 50b and the pin hole 35b in the jib axis direction Xj can be performed only by causing the distal-end perpendicular member 41c to come into contact with (butt against) the perpendicular-member guide member 37c. Thus, it becomes possible to improve efficiency of the operation of coupling the lower jib 40 and the intermediate tapered jib 31c of the upper jib 31.
(Effect 6)
A jib coupling process in the above embodiment is a process of coupling the assembling-type jib 30 which is configured to be attached to the tip (boom head 10t) of the boom 10 illustrated in
In the rope winding step of the jib coupling method, the reeving rope R4 is wound by the reeving winch 7 illustrated in
With reference to
As illustrated in
The roller supporting device 169 supports the roller 65 in such a manner that the roller 65 is movable between a protruding position where the roller 65 protrudes outwardly from the distal end of the lower jib frame 41, and a retracted position where the roller 65 is retracted from the protruding position toward the lower jib frame 41. The roller supporting device 169 is configured, when or after the lower jib frame 41 and the upper jib 31 are coupled together, as illustrated in
For example, this type of roller supporting device 169 comprises a frame-side support portion 169a, and a roller-side support portion 169b. The frame-side support portion 169a is fixed to the lower jib frame 41. For example, it is fixed to the distal-end lateral member 41b. Alternatively, the frame-side support portion 169a may be fixed to the distal-end perpendicular member 41c. As illustrated in
(Effect 7)
An effect of the lower jib 140 equipped with the roller supporting device 169 will be described below. The lower jib 140 comprises the roller supporting device 169 supporting the roller 65 in such a manner as to allow the roller 65 to be retracted toward the lower jib frame 41. The roller supporting device 169 is configured, when or after the lower jib frame 41 and the upper jib 31 (see
The roller supporting device 169 can couple the lower jib 140 and the upper jib 31 (see
With reference to
The roller supporting device 269 supports the roller 65 in such a manner as to allow the roller 65 to be moved with respect to the lower jib frame 41 in the jib axis direction Xj. The roller supporting device 269 is attached to the distal-end lateral member 41b. For example, the roller supporting device 269 comprises a roller side support portion 169b bendable with respect to the frame-side support portion 169a in the jib lateral direction Zj.
For example, the roller supporting device 369 comprises a roller side support portion 169b rotatable sideways and rotatable 180-degree with respect to a frame-side support portion 169a in the jib axis direction Xj. As illustrated in
It is to be understood that various modifications may be made in the above embodiment.
Although the above embodiment has been made based on an example where the boom head 10t and the lower jib 40 are designed for the enfolding support type, the boom head 10t and the lower jib 40 may be designed for the jib offset type.
Alternatively, for example, the boom head 10t and the lower jib 40 may be designed for the extending type. In a boom head 10t for the extending type, the boom-side jib foot 15f is disposed at the same position as that in a boom head for the enfolding support type, without providing the boom-side support portion 15s.
In the above embodiment, the guide bracket 37 is provided in the intermediate tapered jib 31c of the upper jib 31, as illustrated in
In the above embodiment, the guide bracket 37 is provided in the connection section between the lower jib 40 and the intermediate tapered jib 31c. Alternatively, the guide bracket 37 may be provided in either one of the following regions (a) to (c).
(a) A connection section of the jib 30 other than the connection section between the lower jib 40 and the intermediate tapered jib 31c. For example, such a connection section may include a connection section between the intermediate tapered jib 31c and the intermediate jib 31b illustrated in
(b) A connection section of the boom 10. For example, such a coupling section may include a connection section between the top boom 10c and the intermediate boom 10b, and a connection section between the intermediate boom 10b and the lower boom 10a.
(c) A connection section of the strut 20. For example, such a coupling section may include a connection section between a base end-side member of the front strut 20f, and a distal end-side member of the front strut 20f.
In advance of transportation of the crane, the boom 10 is disassembled and transported. In this case, under the condition where the top boom 10c (boom head) and the lower jib 40 are coupled together, the top boom 10c may be detached from the intermediate boom 10b, and transported by a trailer loaded with the detached top boom 10c and the lower jib 40 formed in an integral structure.
When the top boom 10c is detached from the intermediate boom 10b, a coupling section 407b between the intermediate boom 10b and the top boom 10c, on the boom back side Yb1, is maintained in a pin-joined state, whereas a pin-joined state of a coupling section between the intermediate boom 10b and the top boom 10c, on the boom belly side Yb2 is released. Then, a portion of the lower jib 40 on the side of the distal end thereof is hoisted up using a hanging hook 425 of an auxiliary crane via a rope 445, and the top boom 10c and the lower jib 40 is coupled together by a rod-shaped coupling member 440. In this way, the top boom 10c and the lower jib 40 are coupled together by the coupling member 440, so that a relative position between the top boom 10c and the lower jib 40 is fixed so as to keep the lower jib 40 from rotating with respect to the top boom 10c. Then, the distal end of the lower jib 40 is further hoisted up by the auxiliary crane, so that the lower jib 40 and the top boom 10c integrally rotate with respect to the intermediate boom 10b, about the pin of the coupling section 407b, and set in a state illustrated in
The above embodiment can be outlined as follows.
A crane according to the above embodiment comprises: a crane body; a boom attached to the crane body in a raisable and lowerable manner; a luffing jib attached to a head of the boom in a raisable and lowerable manner; and a strut attached to the head of the boom in a raisable and lowerable manner, and configured to raise and lower the luffing jib. The luffing jib comprises: a lower jib making up a first portion of the luffing jib, wherein the first portion extends over a specific range from a base end of the luffing jib toward a tip of the luffing jib and wherein the lower jib is attached to the head of the boom in a raisable and lowerable manner, at a position located below an attaching position of a base end of the strut to the head of the boom in a state in which the boom is lowered and laid down; and an upper jib making up a second portion of the luffing jib, the second portion positioned between the tip of the luffing jib and the lower jib, wherein the upper jib is coupled to the lower jib in such a manner as to be separable from the lower jib. The lower jib is attached to the head of the boom to have a laid-down posture at a position between the boom and the strut when the upper jib is separated from the lower jib, when the boom is lowered and laid down to allow the head of the boom to come into contact with the ground and when the strut is lowered and laid down to allow a distal end of the strut to come into contact with the ground. The lower jib has a length which causes no interference with the strut when the lower jib has the laid-down posture at the position between the boom and the strut.
Preferably, in the above crane, the lower jib comprises a roller which supports an end of the lower jib on a side opposite to the head of the boom on a ground surface while being rollingly movable on the ground surface, under the condition where the upper jib is separated from the lower jib.
More preferably, in this case, the lower jib comprises: a lower-side connector provided at the end of the lower jib on the side opposite to the head of the boom; and a roller shaft which is a rotation shaft of the roller, wherein the lower-side connector has a pin hole capable of allowing the roller shaft, and a pin for coupling the upper jib to the lower-side connector, to be selectively inserted thereinto.
More preferably, in the crane where the lower jib has the roller, the lower jib comprises: a jib foot provided at a base end of the lower jib and attached to the head of the boom; a frame extending from the jib foot toward the side opposite to the head of the boom; and a roller supporting device provided at a distal end of the frame, which is an end of the frame on a side opposite to the jib foot, to support the roller in such a manner as to allow the roller to move between a protruding position where the roller protrudes outwardly from the distal end of the frame and a retracted position where the roller is retracted from the protruding position toward the frame.
Preferably, in the above crane, the lower jib comprises a lower-side connector provided at the end of the lower jib on the side opposite to the head of the boom; and the upper jib comprises an upper-side connector provided at an end of the upper jib on a side coupled to the lower jib, and coupled to the lower-side connector, wherein each of the lower-side connector and the upper-side connector has a pin hole, so that the lower-side connector and the upper-side connector are coupled together by inserting a pin into the pin holes of the lower-side and upper-side connectors, and wherein a first jib as one of the lower jib and the upper jib is provided with a guide bracket configured to guide the lower-side connector and the upper-side connector to a specific relative position where positions of respective pin holes of the lower-side and upper-side connectors are aligned with each other.
More preferably, in this case, a second jib as the other of the lower jib and the upper jib comprises a lateral member provided at an end of the second jib on the side of the first jib to extend in a width direction of the second jib, wherein the guide bracket comprises a lateral-member guide member provided at an end of the first jib on the side of the second jib, and configured to support the lateral member from therebelow, under a condition where the position of the pin hole of the lower-side connector is aligned with the position of the pin hole of the upper-side connector.
More preferably, in the crane where the guide bracket is provided in the first jib, a second jib as the other of the lower jib and the upper jib comprises a perpendicular member provided at an end of the second jib on the side of the first jib to extend in a direction perpendicular to a width direction and an axial direction of the second jib, wherein the guide bracket comprises a perpendicular-member guide member provided at an end of the first jib on the side of the second jib, and configured to be brought into contact with the perpendicular member under a condition where the position of the pin hole of the lower-side connector is aligned with the position of the pin hole of the upper-side connector.
A crane assembling method according to the above embodiment comprises: a preparation step of preparing the crane body while providing the crane body with a reeving winch for winding and unwinding a reeving rope; a boom attaching step of attaching the boom to the crane body; a strut attaching step of attaching the strut to the head of the boom; and a jib attaching and assembling step of attaching the luffing jib to the head of the boom, and assembling the luffing jib. The jib attaching and assembling step includes: a lower jib attaching substep of attaching the lower jib to the head of the boom; an arranging substep of arranging the lower jib and the upper jib under the boom in such a manner that a central axis of the boom, a central axis of the lower jib and a central axis of the upper jib lie on a straight line, in top plan view; a rope connecting substep of: pulling out the reeving rope from the reeving winch in a direction from a base end of the boom to a tip of the boom; wrapping the pulled-out reeving rope around the head of the boom to turn back the pulled-out reeving rope toward the base end of the boom; and connecting the turned-back reeving rope to the upper jib; a rope winding substep of winding the reeving rope using the reeving winch to move the upper jib to come close to the lower jib so as to allow the upper-side connector to be engaged with the lower-side connector; and a connector coupling substep of inserting a pin into respective pin holes of the lower-side and upper-side connectors, under a condition where the upper-side connector is engaged with the lower-side connector, to connect the lower-side and upper-side connectors together, wherein the rope winding substep includes guiding the upper-side connector, by the guide bracket, to an engagement position where the upper-side connector is engaged with the lower-side connector and where the position of the pin hole of the upper-side connector is aligned with the position of the pin hole of the lower-side connector.
This application is based on Japanese Patent applications No. 2012-211945 and No. 2012-211946 filed in Japan Patent Office on Sep. 26, 2012, the contents of which are hereby incorporated by reference.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.
Number | Date | Country | Kind |
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2012-211945 | Sep 2012 | JP | national |
2012-211946 | Sep 2012 | JP | national |