Mobile crane

Abstract

To reduce the workload involved in storing a ladder.SOLUTION: A mobile crane 10, which is disassemblable, has a lower running body 20, an upper rotating body 30 that rotates relative to the lower running body 20, a foothold 321 provided on the side of the upper rotating body 30, and a ladder 40 that can ascend and descend from the foothold 321 to the upper surface side of the upper rotating body 30. The ladder 40 can be changed into a first state in which it is fixed to the side of the upper rotating body 30, and a second state in which it is disposed on the front or rear side of the upper rotating body 30. The upper rotating body 30 has a support part 52 that supports the ladder 40 in the process of changing the position from the first state to the second state.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a mobile crane.

Background Art

[0002] On the side surface of the main body of the working machine, there may be provided a lifting step on which an operator can ride, and a ladder for ascending and descending from the lifting step to the upper surface of the main body. In order to make the left and right dimensions (transport width) smaller during transportation, the ladder and the lifting step provided on the side surface of the working machine are removed from the side surface of the main body and moved from the position where they are used for ascending and descending. In the working machine of Patent Document 1, for example, the ladder provided on the side surface of the main body is rotatably supported at the upper end portion, and during transportation, the lower end portion of the ladder is rotated to retract the entire ladder to the upper surface of the working machine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional working machine, it is necessary to rotate in a large circle with the entire length of the ladder as the turning radius, and the work burden is large to accommodate the ladder on the narrow lifting step.

[0005] An object of the present invention is to reduce the work burden when moving the ladder from the position where it is used.

Means for Solving the Problems

[0006] One aspect of the present invention is a lower traveling body, an upper slewing body that slews with respect to the lower traveling body, A scaffold disposed on a side portion of the upper revolving body, a ladder that can be moved up and down from the scaffold to the upper surface side of the upper revolving body, In a disassemblable mobile crane having, the ladder can be rearranged between a first state fixed to a side portion of the upper revolving body and a second state disposed on the front or rear side of the upper revolving body, the upper revolving body is a mobile crane having a support portion capable of supporting the ladder during the process of rearranging the ladder from the first state to the second state.

Advantages of the Invention

[0007] According to the present invention, the ladder may be rearranged from the side portion of the upper revolving body to the front or rear side, and it is possible to reduce the working burden. In addition, fixing work on the upper surface of the upper revolving body is not required, and it is possible to reduce the working burden also from this surface. In addition, since the ladder is transported after changing its state, it is possible to reduce the labor and cost of transportation by separate transportation.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the embodiments disclosed below. Since the drawings are provided for illustrative purposes only, the scope of the present invention is not limited to the illustrations in the drawings.

[0010] [First Embodiment] FIG. 1 is a right side view of the mobile crane 10, and FIG. 2 is a perspective view of the rear part of the mobile crane 10. A crawler crane is exemplified as the mobile crane 10. The mobile crane 10 includes a lower traveling body 20, an upper slewing body 30, a cab 11, a boom 12, and a counterweight 13. In the following description, in a state where the mobile crane 10 is arranged on a horizontal plane, the vertical up and down direction is defined as "up" and "down" of the mobile crane 10, and the front as seen from the operator in the cab 11 of the upper slewing body 30 is defined as "front", the rear as "rear", the left side of the operator as "left", and the right side as "right". Also, unless otherwise specified, the upper slewing body 30 is in a state where it is not slewing with respect to the lower traveling body 20, and assuming that the front-rear directions of the upper slewing body 30 and the lower traveling body 20 coincide, the terms "up", "down", "left", "right", "front", and "rear" are used. Also, for convenience of explanation, the up-down, left-right directions on the paper surface in each figure, and the direction perpendicular to the paper surface may be used. In that case, the terms "on the paper surface", "under the paper surface", "left on the paper surface", "right on the paper surface", and "perpendicular to the paper surface" are used. Also, the same shall apply to the second embodiment for each direction.

[0011] The mobile crane 10 has a disassembled structure that allows separation and connection between the lower traveling body 20 and the upper slewing body 30. The lower traveling body 20 includes a track frame 21 that rotatably supports the upper slewing body 30 about a vertical axis, and a pair of crawler devices 22 provided on the left and right sides of the track frame 21. The track frame 21 has beams (not shown) extending respectively to the left and right, and the beams are inserted into and connected to the left and right crawler devices 22. Further, the lower traveling body 20 has a disassemblable structure that allows separation and connection between the track frame 21 and the left and right crawler devices 22. Note that the disassemblable structure of the crawler device 22 is not essential.

[0012] The upper slewing body 30 includes a main frame 31 rotatably mounted on the lower traveling body 20, and housings 32 and 33 mounted on the right side and the left side of the main frame 31. Both of the housings 32 and 33 are in the shape of a substantially rectangular parallelepiped box, and house a prime mover, hydraulic equipment, electrical components, etc. The housings 32 and 33 may have doors on their outer side surfaces in the left - right direction for accessing the interior.

[0013] A cab 11 is provided on the front side of the right housing 32. The cab 11 is provided with a driver's seat inside and various operating devices for operating the mobile crane 10. The cab 11 can be separated from and connected to the upper slewing body 30, and the upper slewing body 30 has a disassemblable structure with respect to the cab 11. Further, the cab 11 may be movably supported by the main frame 31 so as to be rotatable about a vertical axis. Note that the separable and movable configuration of the cab 11 is not essential.

[0014] The main frame 31 rotatably supports the lower end of the boom 12 about an axis along the left - right direction by an extension portion extending forward between the housings 32 and 33. The boom 12 can be connected to and separated from the main frame 31, and the upper slewing body 30 has a disassemblable structure with respect to the boom 12.

[0015] Further, the main frame 31 supports the counterweight 13 by an extension portion extending rearward between the housings 32 and 33. The counterweight 13 is attached to the rear part of the upper slewing body 30. The counterweight 13 is arranged on the side opposite to the boom 12 to achieve weight balance with the boom 12 and the suspended load. The counterweight 13 is used in a stacked number according to the weights of the boom 12 and the suspended load at the extending part of the rear end of the main frame 31. All of the counterweights 13 are removable with respect to the main frame 31, and the upper slewing body 30 has a disassembled structure with respect to the counterweights 13.

[0016] As shown in FIG. 2, on the left and right side parts of the upper slewing body 30, more specifically, at the lower ends of the right housing 32 and the cab 11, there are provided scaffolds 321, 111 called so-called catwalks in a state of extending rightward. Also, at the lower end of the left housing 33, a scaffold (not shown) similarly extending leftward is provided. These scaffolds 321, 111 are used during various operations of the mobile crane 10, and are all substantially flat plate bodies that are long in the front-rear direction and have a width that allows one operator to stand in the left-right direction, and are supported by the upper slewing body 30 while maintaining a horizontal state. The scaffolds 321, 111 can be attached to and detached from the upper slewing body 30 or the cab 11, and the upper slewing body 30 has a disassembled structure with respect to the scaffolds 321, 111.

[0017] [Ladder and its support structure] The upper slewing body 30 is provided with a ladder 40 that can be raised and lowered from the scaffold 321 to the upper side of the housing 32 of the upper slewing body 30 in the vicinity of the rear part of the right side surface of the housing 32. FIG. 3(A) is a right side view around the ladder 40, FIG. 3(B) is a rear view, and FIG. 4 is a plan view. The ladder 40 can be repositioned between a first state where it is fixed to the right side portion of the housing 32 on the right side of the upper slewing body 30, and a second state where it is disposed at the rear side of the housing 32 on the right side of the upper slewing body 30. FIGS. 3(A) and 3(B) illustrate the ladder 40 in the first state, and FIG. 4 shows the ladder 40 in the first state as a dashed two-dot line, and the ladder 40 immediately before transitioning to the second state and the ladder 40 in the second state as solid lines.

[0018] Regarding the ladder 40, the front-rear direction shown in FIG. 3(A) is defined as the "width direction W" of the ladder 40, the up-down direction shown in FIG. 3(A) is defined as the "lifting direction H" of the ladder 40, and the left-right direction shown in FIG. 3(B) is defined as the "depth direction N". Note that the width direction W, the lifting direction H, and the depth direction N are orthogonal to each other. Also, the ladder 40 is attached in a state of being closely opposed to the right side surface of the housing 32 in the first state, and is attached in a state of being closely opposed to the rear surface of the housing 32 in the second state.

[0019] The ladder 40 has a pair of square bar-shaped struts 41 parallel to the lifting direction H on both sides in the width direction W. Between the pair of struts 41, a plurality of treads 42 along the width direction are provided at uniform intervals in the lifting direction H. Each tread 42 is in the shape of a round bar and serves as a foothold when the ladder 40 is lifted or lowered. Note that the shape of each strut 41 is not limited to a square bar shape and may be any shape. For example, it may be a round bar shape or other shapes. The shape of each tread 42 is not limited to a round bar shape and may be any shape. For example, it may be a square bar shape or other shapes. The ladder 40 is formed from a metal material in which each part has sufficient strength for its intended use. Each part constituting the ladder 40 may have a solid interior, but in order to reduce weight, members with a hollow interior may also be used.

[0020] The lower end of each support column 41 is located above the upper surface of the scaffold 321 and near the scaffold 321. Further, the lower end of each support column 41 is bent in one direction (the left side shown in FIG. 3(B)) in the depth direction N of the ladder 40, and a contact member 43 that contacts the opposing surface of the tip (for example, the right side surface of the house 32 that opposes in the first state) is provided at the tip. The contact member 43 is a disk-shaped member made of a material softer than metal, such as resin, and has a contact surface that contacts the right side surface of the house 32. Note that the contact member 43 is not limited to the above shape, structure, and material as long as it has a structure that does not damage the contact partner. Further, the contact member 43 may be formed of a material that generates a predetermined frictional force with respect to the contact surface, such as rubber or soft resin, to provide an anti-slip function.

[0021] At the upper end of each support column 41, arm portions 44 and 45 extending in the same direction as the lower end of the support column 41 are provided. The arm portions 44 and 45 of each support column 41 extend in the depth direction N and also extend in a direction that spreads somewhat outward in the width direction W. Further, each of the arm portions 44 and 45 extends somewhat longer in the depth direction N than the contact surface of the contact member 43. And at the tip of each of the arm portions 44 and 45, connecting bodies 46 and 47 for attaching the ladder 40 to the house 32 are provided.

[0022] One connecting body 46 is a cylindrical member, and is fixed to the tip of the arm portion 45 with its axis directed parallel to the lifting direction H. This connecting body 46 is provided on the arm portion 45 that is farther from the ladder 40 arranged in the second state in the first state. Specifically, it is the arm portion 45 located on the front side in FIG. 3(A). The connecting body 46 is penetrated along the lifting direction H, and a shaft member 51 or 52 described later having an outer diameter approximately the same as its inner diameter can be inserted and removed, and is rotatable with respect to the shaft member 51 or 52.

[0023] The other connecting body 47 is a substantially semi-cylindrical member having an open cross-sectional shape when viewed in the elevating direction H, more specifically, a substantially U-shaped member. The height of the connecting body 47 in the elevating direction H is equal to that of the connecting body 46, and it is open in the direction away from the support column 41 in plan view. Based on the ladder 40 (the ladder 40 immediately before transitioning to the second state) shown by the solid line in the same direction as the direction of the ladder 40 shown by the two-dot chain line in FIG. 4, the planar shape of the connecting body 47 will be described in more detail. The connecting body 47 is composed of a pair of side walls 471 whose open side extends in the direction away from the support column 41 (leftward), and the non-open side is composed of a semi-circular portion 472 having a semi-circular shape. The distance between the pair of side walls 471 on the open side and the inner diameter of the semi-circular portion 472 on the non-open side (rightward) are equal to the inner diameter of the cylindrical connecting body 46. Note that the pair of side walls 471 of the connecting body 47 may be somewhat expanded toward the open side. While the connecting body 46 described above has a structure in which the shaft member 51 or 52 is inserted and connected from the elevating direction H, the connecting body 47 has a structure in which the shaft member 52 or 53 described later is received from the open side of the pair of side walls 471 and held by the semi-circular portion 472 on the non-open side.

[0024] Note that a lock mechanism 48 for fixing the received shaft member 52 or 53 at the semi-circular portion is provided on one side in the width direction of the ladder 40 (for example, inside the pair of arm portions 44, 45) in the connecting body 47. This lock mechanism 48 has a lock pin 481 that can be slid so as to penetrate the semi-circular portion 472 of the connecting body 47 and the shaft member 52 or 53 accommodated in the semi-circular portion 472 in its diameter direction, and a support frame 482 that slidably supports the lock pin 481. Note that the lock pin 481 and its sliding direction are parallel to the width direction W. In addition, through holes (not shown) through which the lock pin 481 passes are formed on both sides in the diameter direction of the semi-circular portion 472 of the connecting body 47 and in the diameter direction of the shaft members 52 and 53. Note that the through holes of the shaft member 52 are formed parallel to the front-rear direction, and the through holes of the shaft member 53 are formed parallel to the left-right direction. The lock pin 481 is provided with a lever-shaped operation portion 483, and by operating the operation portion 483, it is possible to switch between a state in which the shaft member 52 or 53 is fixed by the lock pin 481 and a released state.

[0025] Next, the support structure for supporting the ladder 40 in the first state and the support structure for supporting the ladder in the second state will be described. The support structure for supporting the ladder 40 in the first state includes a shaft member 51 provided at the front end of the upper surface of a base member 54 that is a long base in the front-rear direction provided near the rear end portion of the upper surface of the house 32 and at the right edge, and a shaft member 52 provided at the rear end portion of the upper surface of the base member 54. Both the shaft members 51 and 52 are shaft members with the same outer diameter, and are provided on the base member 54 such that their axes are parallel to the vertical direction. Further, these shaft members 51 and 52 are set to an outer diameter that can be inserted into the connecting body 46 of the ladder 40 described above.

[0026] The shaft member 52 is disposed at the corner of the right rear end of the upper surface of the house 32, and the shaft member 51 is disposed in front of the shaft member 52. Also, the center-to-center distance between the shaft member 51 and the shaft member 52 is equal to the center-to-center distance between the connecting body 46 of the ladder 40 and the semi-circular portion 472 of the connecting body 47.

[0027] The support structure for supporting the ladder 40 in the second state includes the aforementioned shaft member 52 and a shaft member 53 provided near the rear end portion of the upper surface of the house 32 and to the left of the shaft member 52. That is, the support structure in the first state and the support structure in the second state share the shaft member 52. The shaft member 53 is a shaft member having the same outer diameter as the shaft member 52, and is provided on the upper surface of the house 32 such that its axis is parallel to the vertical direction. Also, the center-to-center distance between the shaft member 52 and the shaft member 53 is equal to the center-to-center distance between the connecting body 46 of the ladder 40 and the semi-circular portion 472 of the connecting body 47. Further, unlike the shaft member 52, the shaft member 53 is not provided on the base member 54, so the shaft member 53 has a height obtained by adding the height of the base member 54 to the shaft member 52.

[0028] [Ladder Arrangement Change Operation] The operation of switching the arrangement of the ladder 40 having the above configuration from the first state to the second state will be described. The arrangement of the ladder 40 in the first state located on the right side of the house 32 is an arrangement for an operator to move up and down with respect to the upper side of the house 32 using the ladder 40. When the mobile crane 10 is performing a lifting operation, the ladder 40 is arranged in the first state. On the other hand, the arrangement of the ladder 40 in the second state located at the rear of the house 32 is an arrangement for accommodating the ladder 40 when disassembling, transporting, storing, etc. each part of the mobile crane 10. In the following description, it is assumed that, as one of the steps of disassembling each part of the mobile crane 10, the arrangement of the ladder 40 is switched from the first state to the second state. Also, it is assumed that the scaffold 321 has not been removed yet, and an operator switches the arrangement of the ladder 40 from the first state to the second state on the scaffold 321.

[0029] In the ladder 40 in the first state, the connecting body 46 is held by the shaft member 51, and the connecting body 47 is held by the shaft member 52. In this state, the shaft member 52 functions as a "first fixing portion" for fixing the ladder 40 in the first state. In this state, when the locking pin 481 of the locking mechanism 48 is operated in the releasing direction and the entire ladder 40 is pushed upward, the holding states of the connecting bodies 46 and 47 are released. Note that the shaft member 52 as the "first fixing portion" may have any structure capable of fixing the end portion of the ladder 40 on the connecting body 47 side. For example, the shaft member 52 and the connecting body 47 may have a structure having an insertion portion of the shaft member and the shaft member (which may be reversed). Alternatively, the shaft member 52 and the connecting body 47 may have a structure in which a concave portion and a convex portion (which may be reversed) are fitted to each other.

[0030] Next, as shown in FIG. 4, while keeping the direction of the ladder 40 the same as that in the first state, move backward on the scaffold 321 so that the shaft member 52 is inserted into the connecting body 46, and connect the connecting body 46 and the shaft member 52. In this state, the shaft member 52 functions as a "support portion" for supporting the ladder 40 in the process of changing the arrangement from the first state to the second state. Note that the shaft member 52 as the "support portion" may have any structure capable of supporting the ladder 40 in the process of changing the arrangement from the first state to the second state. Also in this case, for example, the shaft member 52 and the connecting body 46 may have a structure having an insertion portion of the shaft member and the shaft member (which may be reversed). Alternatively, the shaft member 52 and the connecting body 46 may have a structure in which they are fitted to each other by a concave portion and a convex portion (which may be reversed).

[0031] Next, when the ladder 40 is rotated about the shaft member 52 in the direction in which the connecting body 47 faces the shaft member 53, the shaft member 53 is received inside the connecting body 47, and the shaft member 53 is fitted into the semi-circular portion 472, and the semi-circular portion 472 restricts the ladder 40 from rotating further. That is, the connecting body 47 functions as a "restricting portion" that restricts the ladder 40 from rotating further at the position where it becomes the second state. Note that the connecting body 47 as the "restricting portion" may have any structure capable of restricting the change in position so that the ladder 40 is determined at a predetermined position in the second state. For example, the connecting body 47 and the corresponding shaft member 52 may have a structure having an insertion portion of the shaft member and the shaft member (which may be reversed), and may have a contact portion that serves as a stopper so that the movement stops in the second state. Alternatively, the connecting body 47 and the corresponding shaft member 52 may have a structure in which they are fitted to each other by a concave portion and a convex portion (which may be reversed), and may have a contact portion that serves as a stopper so that the movement stops in the second state.

[0032] Then, the locking pin 481 of the locking mechanism 48 is operated to connect the connecting body 47 and the shaft member 53. Thereby, the ladder 40 is fixed in the arrangement in which it becomes the second state. That is, the shaft member 53 functions as a "fixing portion" for fixing the ladder 40 in the second state.

[0033] [Technical Effects of the First Embodiment] The mobile crane 10 having the above-described configuration has a structure in which the upper slewing body 30 can support the ladder 40 in the process of changing the arrangement from the first state to the second state. For example, it has a shaft member 52 that supports the ladder 40 so as to be rotatable. Therefore, in a part of the process of changing the arrangement of the ladder 40 from the scaffold 321 disposed on the side portion of the upper slewing body 30, the ladder 40 is rotated about the shaft member 52 along the elevating direction H (vertical direction). Thus, the rotation operation can be performed without supporting the entire weight of the ladder 40, and it can be easily moved to the arrangement in the second state with a small force. Among conventional cranes, there are some that get off the scaffold and move the ladder to another place. In such a case, however, since one has to get on and off the scaffold using the ladder, there is a problem that the work burden becomes extremely large. As described above, the mobile crane 10 can perform the arrangement change of the ladder 40 from the first state to the second state with a very small work burden. Furthermore, since the shaft member 52 is a shaft along the elevating direction H, the turning radius of the ladder 40 at that time is the width in the width direction of the ladder 40. Therefore, even on a narrow scaffold 321, the work can be easily performed. By these means, it is only necessary to change the arrangement of the ladder 40 from the first state to the second state, so that the work burden can be dramatically reduced.

[0034] In particular, since the turning radius of the ladder 40 during the arrangement change is small, even when the ladder 40 is rotated to the arrangement in the second state and fixed by the locking mechanism 48, the turning end portion of the ladder 40 does not move far away. Therefore, the work can be easily performed. Also, unlike the case where the entire ladder 40 is placed on the upper part of the upper slewing body 30, the work of climbing onto the upper part of the upper slewing body 30 and fixing the ladder 40 in the absence of the ladder 40 is unnecessary, and the work within the reach by stretching the arm from the scaffold 321 can be easily realized. From this viewpoint as well, it is possible to reduce the work burden.

[0035] In addition, since the ladder 40 can be repositioned to a second state where it is disposed on the rear side of the upper slewing body 30, when disassembling and transporting the upper slewing body 30, it is possible to reduce the width (transport width) during transportation with the ladder loaded on the upper slewing body 30, making it easier to fit within the width that can be loaded onto a transport vehicle, and enabling a configuration suitable for transportation. Conventionally, there has been a problem that if the ladder is removed from the crane and transported separately, additional transportation costs are required. However, when transporting the mobile crane 10, the ladder 40 can be transported while attached to the upper slewing body 30, so it is possible to reduce transportation costs compared to transporting the ladder 40 separately.

[0036] In addition, since the upper slewing body 30 has a shaft member 53 as a second fixing portion for fixing the ladder 40 in the second state, it is possible to stably maintain the ladder 40 in the second state arrangement after the change from the first state to the second state. Therefore, the operation of arranging the ladder 40 in the second state can be easily performed, and the work load can be reduced.

[0037] In addition, the mobile crane 10 can be fixed to the shaft member 53 in a state regulated by a connecting body 47 that regulates the position change of the ladder 40 so that it is determined at a predetermined position in the second state. Therefore, when rotating the ladder 40 to the position in the second state, the connecting body 47 can position the ladder 40 at an appropriate position, facilitating the operation of changing the arrangement of the ladder 40 from the first state to the second state, and further reducing the work load.

[0038] In addition, the mobile crane 10 has a configuration in which a fixing portion for fixing the ladder 40 in the first state and a support portion for rotatably supporting the ladder 40 when changing the arrangement to the second state are shared by the shaft member 52. Therefore, the number of components for supporting the ladder 40 can be reduced, and it is possible to reduce the number of parts and the installation cost. In addition, thereby, the arrangement of the ladder 40 in the first state and the arrangement of the ladder 40 in the second state can be made adjacent to each other, and it is possible to save space in the use and storage of the ladder 40. In addition, since the arrangement of the ladder 40 in the first state and the arrangement of the ladder 40 in the second state are close to each other, the moving distance of the ladder 40 can be shortened, the operation of changing the arrangement from the first state to the second state can be facilitated, and the work load can be further reduced.

[0039] [Second Embodiment] A mobile crane 10 as a second embodiment in which the ladder and its support structure are different from those in the first embodiment will be described. The same components as those of the mobile crane 10 described above are denoted by the same reference numerals, and redundant descriptions are omitted.

[0040] FIG. 5 is a right side view of the periphery of the ladder 60 in the first state, FIG. 6 is a rear view thereof, and FIG. 7 is a plan view thereof. Further, FIG. 8(A) is a cross-sectional view taken along line A-A of FIG. 5, FIG. 8(B) is a cross-sectional view taken along line B-B of FIG. 6, FIG. 9 is a view showing a state during the transition to the second state, and FIG. 10 is a view showing the state after the transition to the second state.

[0041] The ladder 60 is arranged on the side portion of the upper slewing body 30 as the first state, more specifically, on the right side surface side of the right housing 32, and is arranged on the rear portion of the upper slewing body 30 as the second state, more specifically, on the rear surface side of the right housing 32, which is the same as the ladder 40 described above. Also, in the case of the ladder 60, the vertical direction shown in FIG. 5 is the "lifting direction H" of the ladder 40, the front-rear direction shown in FIG. 5 is the "width direction W" of the ladder 60, and the left-right direction shown in FIG. 6 is the "depth direction N" of the ladder 60.

[0042] The ladder 60 has a pair of round bar-shaped struts 61 parallel to the lifting direction H on both sides in the width direction W. A plurality of treads 62 along the width direction are provided at uniform intervals in the lifting direction H. Each tread 62 is round bar-shaped. Also, in the case of the ladder 60, the shape of the struts 61 is not limited to round bar shape, and may be any shape such as square bar shape or other shapes. Also, the shape of each tread 62 is not limited to round bar shape, and may be any shape such as square bar shape or other shapes. Further, the lower end portion of each support column 61 is bent toward the house 32 side in the depth direction N, and a contact member 63 is provided at the tip thereof. The contact member 63 is the same as the aforementioned contact member 43. Similar to the case of the ladder 40, the ladder 60 is also formed of a metal material in which each part has sufficient strength for its intended use. Each part may have a solid interior, but in order to reduce weight, a hollow member may be used for the interior.

[0043] A top plate 64 is provided at the upper end portion of each support column 61, and a bottom plate 65 that is disposed in the vicinity of the lower side of the top plate 64 and is opposed to the top plate 64 in proximity is provided. The top plate 64 and the bottom plate 65 are flat plates having the same shape and being horizontal in the first state and the second state arrangements of the ladder 60. The top plate 64 and the bottom plate 65 have a shape having a rectangular main body portion 643, 653 that is long in the width direction W in plan view and a pair of arm portions 644, 654 that extend from both end portions thereof toward the support columns 61 in the depth direction (rightward in FIG. 8(A)). Between the top plate 64 and the bottom plate 65, a vertical plate portion 67 and a pair of side plate portions 66 provided in a pair at both end portions in the width direction W are provided. The vertical plate portion 67 is located between the main body portion 643 of the top plate 64 and the main body portion 653 of the bottom plate 65, and is a flat plate that is parallel to the width direction W and parallel to the vertical direction in the first state arrangement of the ladder 60. Each side plate portion 66 is located between the pair of arm portions 644 of the top plate 64 and the pair of arm portions 654 of the bottom plate 65, respectively, and is a flat plate that is parallel to the depth direction N and parallel to the vertical direction in the first state arrangement of the ladder 60. Further, one end portion in the depth direction N (the right end portion in FIG. 8(A)) of the pair of side plate portions 66 is fixed to the upper end portion of each support column 61.

[0044] The top plate 64, the bottom plate 65, the vertical plate portion 67, and each side plate portion 66 are integrally joined to form a U-shaped frame in plan view. A base member 84 serving as a base along the front-rear direction is fixedly installed on the upper surface of the house 32 at the right side edge portion of the upper surface of the house 32 near the rear end portion. The base member 84 is a sectional U-shaped profile that is open toward the right, and has an upper plate portion 844, a lower plate portion 845, and a vertical plate portion 846. The upper plate portion 844 and the lower plate portion 845 are opposed to each other in proximity. The frame composed of the top plate 64, bottom plate 65, vertical plate portion 67, and each side plate portion 66 of the ladder 60 is arranged in a placed state on the upper surface of the upper plate portion 844 of the base member 84 in the first state. Further, a support shaft portion 81 for supporting the ladder 60 is erected at a position slightly rearward from the intermediate position in the front-rear direction on the upper surface of the upper plate portion 844 of the base member 84. The support shaft portion 81 is a round bar-shaped shaft along the vertical direction.

[0045] As shown in FIG. 8(A), the space S between the main body portion 643 of the top plate 64 and the main body portion 653 of the bottom plate 65 is open toward one side (left side) in the depth direction, and a rotating member 68 as a movable portion for moving the ladder 60 from the first state to the second state is arranged in the space S. As shown in FIGS. 8 and 9, the space S is a space surrounded by the main body portion 643 of the top plate 64, the main body portion 653 of the bottom plate 65, the vertical plate portion 67, and the left end portions of the pair of side plate portions 66, and only the left side is open. When the ladder 60 is in the first state, this rotating member 68 is arranged in a stored state in the above space S. The rotating member 68 has cylindrical portions 681 and 682 penetrating vertically through one end portion and the other end portion, respectively. The support shaft portion 81 described above is inserted into the cylindrical portion 681 at one end portion, and the rotating member 68 is supported so as to be rotatable about the support shaft portion 81. In the following description, the side of one end portion (cylindrical portion 681) of the rotating member 68 supported by the support shaft portion 81 is referred to as the base end portion, and the side of the other end portion (cylindrical portion 682) of the rotating member 68 connected to a connecting shaft 69 to be described later is referred to as the rotating end portion. A U-shaped notch 651 is formed in the main body portion 653 of the bottom plate 65 of the ladder 60 so as not to interfere with the cylindrical portion 681 of the rotating member 68 and the support shaft portion 81.

[0046] Further, a connecting shaft 69 that rotatably connects the rotating member 68 and the ladder 60 is inserted into the rotating end portion (cylindrical portion 682 side) of the rotating member 68. The connecting shaft 69 is a round bar-shaped shaft along the lifting direction H, penetrates through the connecting hole 641 (see FIG. 7) of the main body portion 643 of the top plate 64 and a connecting hole (not shown) of the main body portion 653 of the bottom plate 65, and is rotatably inserted into the cylindrical portion 682 of the rotating member 68. Thereby, the ladder 60 can rotate around the connecting shaft 69 with respect to the rotating member 68. Note that since the connecting shaft 69 protrudes downward from the bottom plate 65, a U-shaped notch 841 that opens rightward from the base member 84 is formed in the upper plate portion 844 of the base member 84 so as not to interfere with the upper plate portion 844 of the base member 84, as shown in FIG. 9.

[0047] A ladder regulating plate 70 as a ladder regulating portion for selectively fixing the rotating member 68 to a "superposed state" in which the rotating member 68 and the main body portions 643 and 653 overlap in a plan view and a "crossed state" in which the rotating member 68 and the main body portions 643 and 653 form an angle of 90° around the connecting shaft 69 is fixedly provided at the rotating end portion (cylindrical portion 682 side) of the rotating member 68. Note that the crossed state is exemplified by 90°, but it may deviate slightly from 90°. For example, it may deviate by about plus or minus 5 degrees. In addition, a rotation regulating plate 71 as a rotation regulating portion for selectively fixing the direction of the rotating member 68 when the ladder 60 is in the first state with respect to the housing 32 and the direction of the rotating member 68 when the ladder 60 is in the second state with respect to the housing 32 is fixedly provided at the end portion on the cylindrical portion 681 side of the rotating member 68.

[0048] The ladder regulating plate 70 is a flat plate that is horizontal in the arrangements of the first state and the second state of the ladder 60. The ladder regulating plate 70 has an outer edge portion that is arc-shaped centered on the cylindrical portion 682. As shown in FIGS. 8(A) and 8(B), a through hole 701 for maintaining the rotating member 68 and the main body portions 643 and 653 in a superposed state is formed at one end portion of the arc-shaped outer edge portion of the ladder regulating plate 70. Further, as shown in FIGS. 9 and 10, the ladder regulation plate 70 is formed with a through hole 702 at the other end of the arc-shaped outer edge portion to maintain the main body portions 643 and 653 in a crossed state in which they are rotated counterclockwise by 90° about the connecting shaft 69 with respect to the rotating member 68.

[0049] As shown in FIGS. 8(A) and 8(B), when the ladder 60 is in the first state, the rotating member 68 and the main body portions 643 and 653 are in an overlapping state. In this state, a regulation hole 642 (see FIG. 7) is formed at a position of the main body portion 643 of the top plate 64 that overlaps with the through hole 701 of the ladder regulation plate 70 in a plan view. By inserting the regulation pin 72 into the regulation hole 642 and the through hole 701 simultaneously, the overlapping state can be maintained.

[0050] As shown in FIG. 10, when the ladder 60 is in the second state, the rotating member 68 and the main body portions 643 and 653 are in a crossed state. In this state, the through hole 702 of the ladder regulation plate 70 overlaps with the above-described regulation hole 642 (see FIG. 7) in a plan view. By inserting the regulation pin 72 into the regulation hole 642 and the through hole 702 simultaneously, the ladder 60 can be maintained in a crossed state with respect to the rotating member 68.

[0051] When the rotating member 68 and the ladder 60 rotate between the overlapping state and the crossed state, slits through which the ladder regulation plate 70 passes are formed in the side plate portion 66 and the standing plate portion 67 so that the ladder regulation plate 70 does not interfere with the side plate portion 66 and the standing plate portion 67 of the ladder 60, respectively.

[0052] The rotation regulation plate 71 is a semi-circular flat plate that fixes the rotating member 68 to the base member 84 of the housing 32 in the direction of the ladder 60 in the first state and in the second state. Note that the shape of the rotation regulation plate 71 may be other shapes as long as it extends in the direction of extending the rotating member 68. On the upper plate portion 844 of the base member 84, there are formed a restricting hole 842 for maintaining the rotating end portion of the rotating member 68 (on the side of the cylindrical portion 682) in a state facing forward, and a restricting hole 843 for maintaining the rotating end portion of the rotating member 68 (on the side of the cylindrical portion 682) in a state facing rearward.

[0053] As shown in FIG. 8, when the ladder 60 is in the first state, the rotating end portion of the rotating member 68 is in a state facing forward. A through hole 711 is formed in the rotation restricting plate 71. When the rotating member 68 faces forward, the restricting hole 842 formed in the upper plate portion 844 of the base member 84 and the through hole 711 overlap in a plan view. By inserting the restricting pin 73 into the restricting hole 842 and the through hole 711 simultaneously, the rotating member 68 can be maintained in the orientation when the ladder 60 is in the first state. In order to insert the restricting pin 73 into the restricting hole 842 and the through hole 711 from above, insertion holes 645 (see FIG. 7) and 652 (see FIG. 9) are formed in the top plate 64 and the bottom plate 65, respectively.

[0054] As shown in FIG. 10, when the ladder 60 is in the second state, the rotating end portion of the rotating member 68 is in a state facing rearward. In this state, a restricting hole 843 is formed at a position on the upper plate portion 844 of the base member 84 that overlaps the through hole 711 of the rotation restricting plate 71 in a plan view. By inserting the restricting pin 73 into the restricting hole 843 and the through hole 711 simultaneously, the rotating member 68 can be maintained in the orientation when the ladder 60 is in the second state. Note that when the rotating member 68 faces rearward, the ladder 60 is at a position that does not overlap with the base member 84. Therefore, unlike the case of the restricting hole 842, the restricting pin 73 is inserted only into the restricting hole 843 and the through hole 711.

[0055] [Ladder Arrangement Change Operation] The operation of switching the arrangement of the ladder 60 having the above configuration from the first state to the second state will be described.

[0056] As shown in FIG. 8, in the first state where the ladder 60 is located on the right side of the house 32, the rotating member 68 and the main body parts 643, 653 are in an overlapping state, and the rotating end of the rotating member 68 faces forward.

[0057] And in this first state, the regulating pin 72 is inserted into the regulating hole 642 of the top plate 64 of the ladder 60 and the through hole 701 of the ladder regulating plate 70 at the same time, and the regulating pin 73 is inserted into the regulating hole 842 of the base member 84 and the through hole 711 of the rotation regulating plate 71 at the same time. The ladder 60 can maintain the arrangement in the first state by these regulating pins 72, 73.

[0058] And when switching the ladder 60 to the arrangement in the second state, both of the above-mentioned regulating pins 72, 73 are pulled out, and the ladder 60 is pulled rightward so as to be separated from the right side surface of the house 32. Thereby, as shown in FIG. 9, the rotating end of the rotating member 68 faces rightward, and the main body parts 643, 653 of the ladder 60 rotate counterclockwise by 90° with respect to the rotating member 68 in a plan view and become an intersecting state.

[0059] At this time, since the regulating hole 642 of the top plate 64 of the ladder 60 and the through hole 702 of the ladder regulating plate 70 overlap in a plan view, the regulating pin 72 is inserted into these to maintain the intersecting state of the rotating member 68 and the main body parts 643, 653.

[0060] And as shown in FIG. 10, when the rotating member 68 is further rotated 90° clockwise in a plan view, the ladder 60 reaches the arrangement in the second state located at the rear of the house 32. At this time, since the regulating hole 843 of the base member 84 and the through hole 711 of the rotation regulating plate 71 overlap in a plan view, the regulating pin 73 is inserted into these to hold the state where the directions of the base member 84 and the rotating member 68 are parallel and the rotating end of the rotating member 68 faces the fourth direction close to the position of the ladder 60 in the second state. The ladder 60 is maintained in the arrangement in the second state by these regulating pins 72, 73.

[0061] [Technical Effects of the Second Embodiment] Also in the case of the mobile crane 10 in the second embodiment, the upper slewing body 30 has an operation of changing the direction of the ladder 60 in the entire process of changing the arrangement from the first state to the second state. For example, it has a pivot portion 81 as a support portion that supports the ladder 60 via a rotating member 68 so as to be rotatable. Therefore, similar to the first embodiment, the ladder 60 can be easily moved to the arrangement in the second state with a small force. In addition, since the ladder 60 is moved with a small turning radius using the length of the rotating member 68 as the radius, even on a narrow scaffold 321, it is possible to easily perform the work. By these means, it is possible to reduce the work load of changing the arrangement of the ladder 60 from the first state to the second state. Also, when transporting the mobile crane 10, since the ladder 60 can be transported while being attached to the upper slewing body 30, it is possible to reduce the transportation cost compared to the case of transporting the ladder 60 separately.

[0062] Also, in the case of the mobile crane 10 in the second embodiment, since it has a rotating member 68 as a movable part for moving the ladder 60 from the first state to the second state, the work of attaching and detaching the ladder 60 to and from the upper slewing body 30 is facilitated, and it is possible to further reduce the work load. Furthermore, if the rotating member 68 is configured to support all the weight of the ladder 60, it is possible to further significantly reduce the work load of changing the arrangement from the first state to the second state.

[0063] Also, the upper slewing body 30 has regulating pins 72, 73 as a second fixing portion for fixing the ladder 60 in the second state, so that the ladder 60 can be stably maintained in the arrangement in the second state. And, since the regulating pin 73, which is the second fixing part for fixing the ladder 60 in the second state, is arranged on the arrangement side in the first state in the ladder 60 in the second state, even when the arrangement of the ladder 60 in the second state is separated from the scaffold 321, the insertion work of the regulating pin 73 can be performed at a position close to the scaffold 321, work such as reaching out from the scaffold 321 can be avoided, and a further reduction in the work load can be achieved. Further, the regulating pin 72, which is the fixing part for fixing the ladder 60 in the second state, is inserted into the regulating hole 642 and the through hole 702 arranged at the end part on the first state side (the ladder 60 side arranged in the first state) in the ladder 60 arranged in the second state. That is, as shown in FIG. 10, the regulating pin 72 is arranged in the through hole 702 located at the right front corner part of the ladder 60 located in the second state. Therefore, the insertion work of the regulating pin 72 can be performed at a position close to the scaffold 321, work such as reaching out from the scaffold 321 can be avoided, and a further reduction in the work load can be achieved.

[0064] [Others] As described above, each embodiment of the present invention has been explained. However, the present invention is not limited to the above embodiments. For example, in the embodiment, a component integrally formed by a single member may be replaced with a component divided into a plurality of members and connected or fixed to each other. Further, a component configured by connecting a plurality of members may be replaced with a component integrally formed by a single member. In addition, the details shown in the embodiments can be appropriately changed without departing from the gist of the invention.

[0065] In each of the above embodiments, the configuration in which the ladders 40 and 60 are arranged in the first state fixed to the right side part of the upper revolving body 30 and the second state arranged at the rear side of the upper revolving body 30 is illustrated, but it may be a configuration in which the first state fixed to the left side part of the upper revolving body 30 and the second state arranged at the rear side of the upper revolving body 30. More specifically, it may be a configuration in which the first state is fixed to the left side surface side of the left house 33 and the second state is arranged at the rear surface side of the house 33.

[0066] Furthermore, when it is possible to secure a space for arranging the ladders 40 and 60 on the front side of the upper revolving body 30, it may be configured to be arranged in a first state fixed to the right side portion of the upper revolving body 30 and a second state arranged on the front side of the upper revolving body 30, or in a first state fixed to the left side portion of the upper revolving body 30 and a second state arranged on the front side of the upper revolving body 30. Also, the plurality of ladders 40 and 60 may be arranged in the plurality of arrangement modes described above.

[0067] In addition, although the mobile crane 10 illustrated in each embodiment has an example configuration in which the houses 32 and 33 are arranged on both the left and right sides of the main frame 31 of the upper revolving body 30, it is not limited thereto. For example, in the case of a configuration in which the upper revolving body has a frame-shaped main frame and a house is accommodated inside the main frame, it may be configured to be arranged in a first state where the ladder is fixed to the right or left side portion of the main frame and a second state where it is arranged on the front or rear side of the main frame.

[0068] In the first embodiment, an example configuration is illustrated in which the mobile crane 10 shares the shaft member 52 as a fixing portion for fixing the ladder 40 in the first state and a support portion for rotatably supporting the ladder 40 when changing the arrangement to the second state, but it is not limited thereto. That is, the shaft member as a fixing portion for fixing the ladder 40 in the first state and the shaft member as a support portion for rotatably supporting the ladder 40 may be configured as separate members. In that case, the shaft member as a support portion for rotatably supporting the ladder 40 may be arranged at any position in the front or rear with respect to the shaft member as a fixing portion for fixing the ladder 40 in the first state.

[0069] In addition, the base members 54 and 84 illustrated in each embodiment are not essential configurations. The shaft members 51 and 52 provided on the base member 54 and the support shaft portions 81 provided on the base member 84 may be directly provided on the upper surface of the house 32.

[0070] Also, in each embodiment, when the shaft member 52 or the support shaft portion 81 as the support portion is changed in arrangement from the first state to the second state, the ladders 40 and 60 are rotated to change the orientation and position. However, the configuration is not limited to one in which the support portion is rotatable. For example, the upper swing body 30 may be configured to have a support portion that supports the ladder 40 so as to be slidable. Referring to FIG. 4 for explanation, instead of providing the shaft members 51 to 53 on the upper surface of the house 32, two straight line sections connecting from the position where the shaft member 51 is provided to the position where the shaft member 52 is provided and from the position where the shaft member 52 is provided to the position where the shaft member 53 is provided are connected at a right-angled corner to form an L-shaped guide groove. Then, at the tip portions of the arm portions 44 and 45 of the ladder 40, instead of the connecting bodies 46 and 47, round bar-shaped pins with their ends facing downward are provided, and the pins of the arm portions 44 and 45 are inserted into the portion along the right side edge of the house 32 of the L-shaped guide groove and arranged in the first state. When arranging the ladder 40 in the second state, each pin is slid along the guide groove and slid along the portion along the right side edge and the portion along the rear side edge of the house 32 of the guide groove to move to the target position. It is preferable to use a locking mechanism or a lock pin that prevents sliding movement to fix the ladder 40 at each position of the first state and the second state.

[0071] In the above embodiment, the case where the mobile crane 10 is a crawler crane is illustrated, but it is not limited to this. For example, the ladders 40 and 60 and their support structures can be applied to other mobile cranes such as wheel cranes and truck cranes.

Explanation of Reference Numerals

[0072] 10 Mobile crane 11 Cab 111 Scaffold 13 Counterweight 20 Lower traveling body 30 Upper swing body 31 Main frame 32, 33 House 321 Scaffold 40 Ladder 46 Connector 47 Connector (Regulating Part) 471 Side Wall 472 Semi-Circular Part 48 Locking Mechanism 481 Locking Pin 51 Shaft Member 52 Shaft Member (Support Part, First Fixing Part) 53 Shaft Member (Second Fixing Part) 54 Base Member 60 Ladder 64 Top Plate 641 Connecting Hole 642 Regulating Hole 65 Bottom Plate 68 Rotating Member (Movable Part, Support Part) 69 Connecting Shaft 70 Ladder Regulation Plate 701,702 Through-Holes 71 Rotation Regulation Plate 711 Through-Hole 72,73 Regulation Pins (First Fixing Part, Second Fixing Part) 81 Support Shaft Part (Support Part) 84 Base Member 842,843 Regulation Holes H Lifting Direction N Depth Direction W Width Direction

Claims

1. A lower traveling body, an upper slewing body that slews with respect to the lower traveling body, a scaffold disposed on a side portion of the upper slewing body, a ladder that can be moved up and down from the scaffold to the upper surface side of the upper slewing body, in a detachable mobile crane having: the ladder can be changed in arrangement between a first state fixed to a side portion of the upper slewing body and a second state disposed on a front side or a rear side of the upper slewing body, the upper slewing body has a support portion capable of supporting the ladder during the process of changing the arrangement of the ladder from the first state to the second state. A mobile crane.

2. The mobile crane according to claim 1, wherein the upper slewing body has a second fixing portion for fixing the ladder in the second state.

3. The mobile crane according to claim 2, wherein the mobile crane can be fixed by the second fixing portion in a state regulated by a regulating portion that regulates a change in position so that the ladder is determined at a predetermined position in the second state.

4. The mobile crane according to claim 1, wherein a first fixing portion for fixing the ladder in the first state and the support portion are shared.

5. The mobile crane according to claim 1, having a movable portion that moves the ladder from the first state to the second state without removing the ladder from the upper slewing body throughout the process of changing the arrangement from the first state to the second state.

6. The mobile crane according to claim 5, wherein a second fixing portion for fixing the ladder in the second state is disposed on an end side that is the arrangement side in the first state of the ladder in the second state.

Images