JPH10330080A - Middle folding type bridge-shaped crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a middle folding type bridge-shaped crane which can lessen the requisite rope tension as much as practicable and can work well with the recent tendency of large-sized construction of crane. SOLUTION: A boom 3 is composed of a base end boom part 11 coupled 13 with the tip 9a of a girder 9 and a forefront boom part 12 coupled 14 with the tip 11a of the base end boom part 11. The forefront boom part 12 is held horizontally when the boom part 11 is put in the falling position and rising position using a horizontal attitude holding rope 24 of a certain length having the first rope path 241 set over between the first sheave 21 furnished on the base end boom part 11 and the second sheave 22 furnished on the forefront boom part 12 and the second rope path 242 set over between the second sheave 22 and a third sheave 23 furnished on the girder 9 side. The forefront boom part 12 is configured so that an extension part 12c is furnished as protruding from the base end part 12b toward the girder 9. The base end boom part 11 is provided with a recess 11c which permits the extension part 12c to emerge and retract without interference in association with the rising/falling motions generated by the rotation up and down of the part 11. The second sheave 22 is furnished on the extension part 12c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center-bend type bridge crane, and more particularly, to a girder having a base end at a tip end thereof which is rotatable vertically between a falling position and a standing position. A middle-bend type bridge crane comprising a boom comprising a connected base end boom portion and a front end boom portion connected to a base end portion so as to be vertically rotatable relative to a front end portion of the base end boom portion, In particular, a first rope route looped around a first sheave provided on the proximal boom portion and a second sheave provided on the distal boom portion, and a third rope provided on the second sheave and the girder side.
When the base boom portion is located at the lying position and the upright position, the tip boom portion is held in a horizontal state by a constant length horizontal holding rope having a second rope path wound around the sheave. Related to a folded-type bridge crane.

[0002]

2. Description of the Related Art As shown in FIG. 10, this type of a mid-bend type bridge crane has a girder 9 having a tip end 9a at a falling position (position (A) in FIG. 10) and a standing position (position (B) in FIG. 10). ), The base end portion 11b of which the base end portion 11b is connected 13 so as to be freely rotatable up and down, and the front end portion 11 of the base end boom portion 11.
a boom 3 comprising a distal end boom portion 12 having a proximal end portion 12b connected to the base end portion 12b so as to be rotatable up and down relative to the first sheave 21 provided at the distal end portion 11a of the proximal end boom portion 11; The first rope path 24 ₁ wrapped around the second sheave 22 provided on the base end portion 12b of the tip boom portion 12
And the support 10 erected on the second sheave 22 and the girder 9
The second sheave around the third sheave 23 provided at the upper end of the
Leveling rope fixed length with a rope path 24 ₂ 24
Thus, there is known a configuration in which the distal end boom portion 12 is held in a horizontal state when the base end boom portion 11 is located at the lying position and the upright position (hereinafter, referred to as “conventional crane”) ( For example,
No. 22,268).

[0003] In such a conventional crane, during a cargo handling operation, the base end boom portion 11 is located at the falling position, and a series of booms 3 horizontally extending from the girder 9 to the sea by the two boom portions 11 and 12 are provided. In such a case, in such a case, the upper end of the column 10 and each of the boom portions 11 and 12 are formed.
The horizontal holding force of each of the boom portions 11 and 12 is also given by the tension bar stretched between them. On the other hand, when the base end boom portion 11 is located at the standing position, the tension bar does not function at all as the boom holding means, and the tip boom portion 12 is held horizontally only by the tension of the horizontal holding rope 24 alone. Become. Therefore, the horizontal holding rope 24 should be selected and designed based on the necessary tension of the horizontal holding rope 24 when the base end boom portion 11 is positioned at the upright position (hereinafter referred to as “necessary rope tension”). Is preferred.

[0004] Recently, the size of a mid-bend type bridge crane has been remarkably increasing with the increase in the size of container ships, and the length and height of the girder and the boom have become much larger than before. On the other hand, the height of the distal end boom portion 12 when the base end boom portion 11 is located at the upright position cannot be made higher than a certain value due to avoidance of contact with an aircraft or the like. Height). For this reason, the length of the proximal end boom portion 11 which determines the height of the distal end boom portion 12 (the upper limit height of the boom) is greatly restricted in conjunction with the height of the girder. As a result, as the crane becomes larger, the tip boom portion 12 inevitably becomes longer and its weight tends to increase. Therefore, in the case of a recently bent-type bridge-type crane, which tends to become larger, there is a problem that a necessary rope tension is greatly increased, and the fact is that a solution is strongly demanded.

FIG. 10 shows a conventional crane.
As shown in (B), the base boom portion 11 is placed in the upright position.
The distal boom portion 12 when placed is the proximal boom.
The first rope path 24 for the₁To the tension p
For the girder side (post 10), the second rope
Road 24_TwoIs held horizontally by the tension q. This
Here, it acts on the weight of the tip boom portion 12, that is, the center of gravity.
Assuming that the load is w, the tensions p and q and the load w
The vertical distance to the line of action of₁,
h_Two, H_ThreeAs the pivot point of the tip boom portion 12 (both
Mode around boom portions 11 and 12) 14
Considering the balance of the ment, ph between p, q, w
₁+ Qh_Two= Wh_ThreeThere is a relationship. And each row
Path 24₁, 24_TwoThe number of ropes at₁, N
_TwoThen, each rope route 24₁, 24_TwoMake up each
The tension t of the rope portion is the same, p = n₁・ T, q =
n _Two・ Because t, the tip boom portion 12 is held horizontally.
Tension of the horizontal holding rope 24 required for
Rope tension) t is t = wh_Three/ (N₁・ H₁+ N _Two・
h_Two).

Accordingly, in order to keep the required rope tension t small, the moment arms h ₁ and h ₂ with respect to the tensions p and q (hereinafter referred to as “tension moment arms”) may be increased. In addition, the number of ropes n ₁ ,
The required rope tension t can also be reduced by increasing n ₂ , but if the number of rope hooks n ₁ and n ₂ is increased more than necessary, the number of bends of the horizontal holding rope 24 increases and the rope strength is set to a large value. Therefore, it is not appropriate as a measure for reducing the necessary rope tension t.

[0007]

However, in the conventional crane, as shown in FIG. 10B, the first and second sheaves 21 and 22 are connected to the end portions 11 and 12 of the boom portions 11 and 12, respectively.
a, 12b and located at a position close to the rotation fulcrum 14 of the tip boom portion 12, the arms h ₁ and h _{2 of} the tension moment are small, and the necessary rope tension t is reduced. It becomes extremely large with the increase in length and weight, making it difficult to cope with the recent tendency to increase the size of cranes.

Incidentally, the arms h ₁ and h _{2 of the} tension moment
Is changed by changing the positions of the sheaves 21, 22, 23. By devising such positions, the arms h ₁ and h ₂ of the tension moment can be made larger, and the required rope tension t can be made smaller. Is considered possible.

However, in the conventional crane, the arms h ₁ and h ₂ of the tension moment are maximum when the sheaves 21, 22, and 23 are positioned as shown in FIG. It is devised location how not to increase the arm h _1, h ₂ of the tension moment more.

That is, the first and third sheaves 21, 23
If the vertical position is higher than the position shown in FIG. 10B, the arms h ₁ and h ₂ of the tension moment can be further increased. However, since the boom upper limit height is increased, such a method is used. I can't take it. Further, the more the horizontal position of the first sheave 21 is moved from the rotation fulcrum 14 toward the distal end of the distal boom portion 12, the more the arms h ₁ and h ₂ of the tension moment are reduced. Therefore, when the horizontal position of the first sheave 21 is the rear end portion 12b of the front boom portion 12, the arms h ₁ of the tension moment,
h ₂ is maximized. Similarly to the first sheave 21, the second sheave 22 is brought closer to the distal end portion 11a of the base end boom portion 11 so that the arms h ₁ and h ₂ of the tension moment are provided.
Becomes larger. In addition, the mutual positional relationship between the first and second sheaves 21 and 22 needs to be set so that a straight line connecting the two sheaves 21 and 22 is not located below the pivot point 14. This is because, when the straight line is located below the pivot point 14, the moment due to the tension p acts in the same direction as the moment due to the load w.

[0011] From these facts, in the conventional crane
After all, sheaves 21, 22, and 23 are shown in FIG.
Arm at the moment of tension when
h₁, H _TwoIs the largest. Therefore, the required rope tension
t increases with the length and weight of the tip boom portion 12
Such a problem cannot be solved at all.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can reduce the necessary rope tension as much as possible in comparison with a conventional crane, and can appropriately cope with the recent tendency to increase the size of the crane. It is an object of the present invention to provide a bridge type crane that can be bent.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a center-bend type bridge crane, in which, in particular, an extension part which protrudes a boom portion from a base end thereof in a girder direction. In addition, the base boom portion is formed with a concave portion that can protrude and retract without interfering with the extension portion along with the up-and-down operation by the vertical rotation, and the second sheave is formed on the extension portion. It is suggested that it be provided.

[0014]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be specifically described with reference to FIGS.

As shown in FIG. 1, a bridge type crane 1 according to this embodiment includes a crane body 2 and a boom 3.
And a lifting / lowering device 4, a horizontal holding device 5, and a cargo handling device 6. In the following description, for the sake of convenience, front and rear mean left and right in FIG.

As shown in FIG. 1, a crane main body 2 is mounted on a quay 7 so as to be able to run in the left-right direction, and a girder 9 horizontally supported by an upper end of the gantry 8 and extending in the front-rear direction. A support 10 is provided upright at the upper end of the gantry 8 and extends upward in the girder 9.

As shown in FIG. 1, the boom 3 includes a base boom portion 11 and a distal boom portion 12, and extends from the girder 9 to the sea. As is well known, each of the boom portions 11 and 12 and the girder 9 constituting the boom 3 are composed of a main structural member having a steel frame structure and an auxiliary structural member such as a handrail provided on an upper surface thereof. In the drawings, for the sake of convenience, only main constituent members are shown, and auxiliary constituent members are omitted. In the following description, unless otherwise specified, the boom 3, each boom part 11, 12 and girder 9 mean only the main constituent members.

As shown in FIGS. 1 to 3, the base end boom portion 11 has a rear end portion 11b, which is a base end portion thereof, connected to a front end portion 9a, which is a front end portion of the girder 9, so as to be vertically rotatable, ie, undulating.
3, and a raising and lowering device 4 to be described later, a horizontal falling position (solid line position in FIG. 1, FIG. 2 position) connected to the girder 9 and a standing position (FIG. 1 chain line position, FIG. (Position).
In addition, as shown in FIGS.
The rear end portion 12b, which is the base end portion, is connected to the front end portion 11a, which is the front end portion of the base end boom portion 11, so as to be vertically rotatable, that is, to bend freely. The horizontal state is maintained regardless of whether the base end boom portion 11 is located at the lying position or the upright position. The length of the proximal boom portion 11 is set according to the height of the girder 9 and the upper limit height of the boom, and the distal boom portion 12 is connected to the proximal boom portion 1.
It is longer than one.

The tip boom portion 12 is formed in a shape having an extension portion 12c that projects from the rear end portion 12b in the girder direction, that is, backward. In addition, the base portion boom portion 11 is provided with the extension portion 1 along with the undulating operation.
A concave portion 11c that can be made to come and go without interfering with 2c is formed.

Incidentally, the extension portion 12c is connected to the boom portion 1
Since it protrudes rearward from the connection point 14 of the base 1 and 12, it interferes with the base boom portion 11 when the base boom portion 11 is raised and lowered, particularly when the base boom portion 11 is located at the down position. However, such interference can be avoided by providing the base end boom portion 11 with a concave portion in which the extension portion 12c protrudes and retracts with the raising and lowering operation. However, if such a concave portion is provided in the base end boom portion 11, the base end boom portion 11
There is a possibility that the strength of the steel may be reduced. On the other hand, since the base end boom portion 11 is a steel frame structure as described above,
There are various large and small recesses between steel frame members and the like. Therefore, in this embodiment, a part or all of the concave portion naturally present in the base end boom portion 11 which is a steel frame structure is extended when the base end boom portion 11 is located at the lying position. The above-mentioned problem is solved by using the recess 12c in which the recess 12c is immersed. That is, the extension part 12c is
In order to avoid interference with the base end boom portion 11, the shape of the boom portion 11 is such that it protrudes and retracts in the concave portion 11 c naturally present in the structure of the boom portion 11.

As shown in FIGS. 1 to 3, the undulating device 4 includes a sheave 15 provided near the front end 11 a of the base end boom portion 11, a sheave 16 provided at the upper end of the support body 10,
A take-up drum 17 provided on the girder 9 disposed behind the support 10 and a take-up drum 1 from between the sheaves 15 and 16;
7, and tension bars 19, 20 stretched between the base boom portion 11, the distal boom portion 12, and the upper end of the support body 10, and the winding rope 18 is wound around the winding drum. The take-up operation by 17 changes the distance between the two sheaves 15 and 16 so as to expand and contract, so that the base end boom portion 11 can be raised and lowered over the above-described lying position and standing position. Further, each tension bar 19, 20 has a bendable joint 19a, 20a so as to support each boom portion 11, 12 in a horizontal state when the base end boom portion 11 is located at the down position. By extending and pivoting the proximal boom portion 11 to the upright position, it can be folded by the joints 19a, 20a.

As shown in FIGS. 1 to 3, the horizontal holding device 5 includes a first sheave 21 provided on the base boom portion 11, a second sheave 22 provided on the distal boom portion 12, and a girder 9.
The third sheave 23 provided on the side, that is, on the upper end of the support body 10
And a fixed length horizontal holding rope 24 looped between the first sheave 21 and the second sheave 22 and between the second sheave 22 and the third sheave 23.

The first sheave 21 can be provided at any position on the base boom portion 11, but in this example, as shown in FIGS. Have been. The second sheave 22 is shown in FIGS.
As shown in FIG. 3, the extension part 12c of the tip boom part 12 is provided.
And is devised so as to be located behind the rotation fulcrum 14. Note that the second sheave 22 is arranged so as not to protrude upward from the upper surface of the entire tip boom portion including the accessory components described above.

The horizontal holding rope 24, as illustrated in FIGS. 5-7, a first rope path 24 ₁ and the second and third sheaves 22 wound around between the first and second sheaves 21 and 22,
It is those which form a rope hanging form a second rope path 24 ₂ which is wound around between 23, are fixed to both end portions in the crane body 2. The number of the sheaves 21, 22, 23 and the means for fixing the rope end to the crane main body 2 can be arbitrarily set according to the rope hanging form.
That is, the first rope hanging form illustrated in FIG.
(= 1, 2,...) First sheaves 21, N + 1 second sheaves 22, and two third sheaves 23, and an intermediate portion of the horizontal holding rope 24 is connected to each of the first sheaves 21 and the second sheaves. And one end portion is fixed to the crane body 2 from the first second sheave 22 via one third sheave 23 and the other end portion is attached to the (N + 1) th second sheave.
It is fixed 24b to the crane main body 2 from the sheave 22 via the other third sheave 23. In the second rope hanging mode illustrated in FIG. 6, both ends of the horizontal holding rope 24 that has passed through the third sheaves 23 are connected to the crane main body 2.
The sheave 23 provided on the crane body 2
It is fixed to the crane main body 2 by being mutually connected 24c via a and 23a. The other configuration is
It is the same as the first rope hanging mode. Further, the third rope hanging form illustrated in FIG. 7 is a combination of the first rope hanging form and the second rope hanging form. As described at the beginning, it is desirable to take care not to increase the number of ropes more than necessary.

[0025] In Thus, the mutual position of the sheaves 21, 22, the boom base standing position direction of a portion 11 (or the laid posture direction) first rope path 24 ₁ of the rope elongation due to rotational displacement of the the amount (or reduction amount) and the second rope reduced amount of rope path 24 ₂ (or extension amount) and that is consistent, and the tip boom section 12 at the time when the boom base portion 11 is positioned in a collapsed position and the standing position Can be set appropriately on condition that the horizontal direction is maintained by the tensions P and Q of the first and second rope paths 24 ₁ and 24 ₂ (see FIG. 4).

The cargo handling device 6 is, as shown in FIGS.
When the base end boom portion 11 is located at the lying position, a predetermined marine loading / unloading position (solid line position in FIG. 1) is on a series of horizontal rails (not shown) formed on the boom 3 and the girder 9.
Trolley 25 that travels between the trolley 25 and a land loading / unloading position (the position indicated by the two-dot chain line in FIG. 1), a lifting device 27 suspended on the trolley 25 via a lifting operation mechanism 26, and a rope receiving mechanism 2
8, the traveling of the trolley 25 and the lifting and lowering of the hanger 27 are performed in a state where the base end boom portion 11 is located at the lying position, so that the container 30 is moved between the container ship 29 and the land. Is to be transported.

As shown in FIG. 8, the lifting operation mechanism 26 includes a winding drum 31 provided on the girder 9 and a sheave 32 provided on the rear end 9b of the girder 9 from the winding drum 31. Sheave 33 and hanger 27 provided on trolley 25
And a wire rope 35 fixed to the front end portion 12a, which is the tip end of the tip boom portion 12, via the sheave 34 provided at the end of the trolley 25 by operating the winding drum 31 regardless of the position of the trolley 25. The tool 27 is configured to move up and down.

The rope receiving mechanism 28 includes a base end boom portion 1.
Tip boom when 1 is in the upright position
12 from the front end 12a to the trolley 25
This is to prevent the portion 35a from hanging down,
As shown in FIG. 9, the wire rope portion 35a is held.
Holding portion 36a, which is disposed in front of the trolley 25 and
Rope receiver 36 supported movably on horizontal rails
And one end is fixed to the rear end 9b of the girder 9 and
A sheave 37 whose end is provided at the rear end of the rope receiver 36
A first rope 38 fixed to the front end of the trolley 25 through
One end is fixed to the front end 12a of the tip boom portion 12.
The other end is provided at the front end of the rope receiver 36.
B39, a front end portion 12a of the front boom portion 12.
At the rear end 9b of the girder 9.
The trolley 25 is fixed to the rear end of the trolley 25 through the beam sheave 42.
And two ropes 43. Thus, the first rope 38
Rope from the fixed end to girder 9 to sheave 37
Part and rope part from sheave 37 to trolley 25,
Fixed portion of second rope 43 to tip boom portion 12
Rope from sheave 39 to sheave 39
The ropes leading to the loop 40 are parallel to each other and
When the loli 25 travels, the rope receiver 36 travels on a trolley.
Following the trolley travel amount L in the same direction as the traveling direction
I am being squeezed. In addition, trolley 25 and
The positional relationship with the loop receiver 36 is indicated by a solid line in FIG.
And the trolley 25 is located at the sea loading position shown by the solid line in FIG.
When the rope receiver 36 is
Without separating from the front end portion 12a (see FIG. 1).
Position indicated by the line, hereinafter referred to as "the foremost position")
Is set to By the way, the tip boom part
12 is longer than the base boom portion 11 as described above.
Trolley 25 and rope receiver
36 is set as described above,
Position the girder 9 at the appropriate position of the girder 9 (the position indicated by the dashed line in FIG. 1).
(Hereinafter referred to as “standing position”).
As a result, the rope receiver 36 is moved to the end boom portion 12.
Corresponding to the base end portion 12b (shown by a dashed line in FIG. 1).
Position, hereinafter referred to as the “rope receiving position”).
You can let it go. That is, the trolley 25 is loaded on the sea
Travel distance L when traveling from the role position to the standing position₁To
On the other hand, the rope receiving body 36 is moved from the foremost position to the rope receiving position.
L₁/ 2 is followed (see FIG. 1). one
On the other hand, the total length of the tip boom portion 12 is approximately L₁/ 2 and the base
The total length of the end boom portion 11 is L ₁Much shorter than / 2
, The distance L from the sea loading position to the standing position₁Is both
It becomes longer than the total length of the boom portions 11 and 12. The result
As a result, the standing position is necessarily behind the base end boom portion 11.
And it is determined on the girder 9.

Therefore, according to the rope receiving mechanism 28, when the trolley 25 is located at the standing position and the base end boom portion 11 is erected, the wire extending from the trolley 25 to the front end portion 12a of the distal end boom portion 12 is formed. At the bent portions of both boom portions 11, 12, the rope portion 35a is
The holding part 3 of the rope receiver 36 located at the rope receiving position
6a, and the hanging of the wire rope portion 35a can be prevented well. In addition, when the base end boom portion 11 stands, the trolley 2
5 is supported on the girder 9 and satisfies the basic working conditions of the center-bend bridge crane 1.

In the center-bend type bridge crane 1 constructed as described above, the tip boom portion 12 is connected to the extension portion 12.
c, and the second sheave 22 is devised so that it can be positioned behind the rotation fulcrum 14 (the connection point of the two boom portions 11, 12) of the tip boom portion 12.
The tension (required rope tension) T of the horizontal holding rope 24 required to hold the distal boom section 12 horizontally when the base end boom section 11 is located at the upright position.
Can be greatly reduced as compared with the conventional crane shown in FIG.

That is, when the base boom portion 11 is located at the upright position, as shown in FIG. 4, the distal boom portion 12 is moved from the base boom portion 11 in the same manner as in the conventional crane. 1 for the rope path 24 ₁ tension P by addition girders 9 side (the pillar body 10) becomes to be horizontally held by the second rope path 24 ₂ of the tension Q, tension P from the pivot point 14, Q The arms H ₁ , H ₂ of the vertical distance to the action line, ie, the tension moment, position the second sheave 22 behind the rotation fulcrum 14.
The tension moment of the conventional crane is larger than the arms h ₁ and h ₂ . And the arms H ₁ and H _{2 of} this moment
Is increased as the horizontal position of the second sheave 22 in the state where the base end boom portion 11 is located at the upright position is moved backward, particularly as the position is shifted backward from the position of the first sheave 21.

Incidentally, the tension P is
In order to act as a horizontal holding force,
Moment due to the weight W of the tip boom portion 12
In order to act in the opposite direction to the
It is necessary to pass behind the rotation fulcrum 14. Also,
In order for the tip boom portion 12 to be held horizontally,
Both, the rotational displacement of the base end boom portion 11 toward the standing position
With the first rope route 24₁Elongation changes,
The first rope path 24 with the rotational displacement in the direction ₁Is shrinking
It needs to change. However, these conditions are
As long as the probe 22 is located in the rear direction of the pivot 14.
Position of the first and second sheaves 21 and 22
Even if you leave it, you will be satisfied. Therefore, the first and
In determining the positions of the second sheaves 21 and 22,
There is no need to consider the exact conditions.

Therefore, the weight of the tip boom portion 12
The load acting on the center of gravity of W
The arm of the moment_Three, Each rope route 24₁, 24_Two
The number of ropes at₁, N_Two(For example, FIG. 5 or
In the rope hanging mode shown in FIG.₁= 6, N_Two= 2
In the rope hung configuration shown in FIG.₁= 12, N_Two=
4) The required rope tension T (= W · H) obtained as
_Three/ (N₁・ H₁+ N _Two・ H_Two) Under the same condition (W =
w, H_Three= H_Three, N₁= N₁, N_Two= N_TwoBelow)
Is compared to the required rope tension t of a conventional crane,
It can be significantly reduced. As a result, the tip boom
Even when the part 12 is elongated and heavy,
Disadvantages such as making the diameter of the loop 24 larger than necessary
To cope with the large-sized crane 1
Can be.

Further, the second sheave 22 is moved after the pivot 14.
The tension Q is maintained at the proximal boom portion 11.
Of the undulating rope 18 necessary to hold the
This will act to reduce the tension R. That is,
As shown in FIG. 4, the rotation fulcrum 13 (girder 9
(The point of connection between the shaft and the base end boom portion 11)
The arm of the moment of H_Four, The weight of the proximal boom part 11
The load acting on the ball center of gravity is W₀, This load W₀Pivot of
The moment arm for point 13 is H_Five, Tension Q, R times
The moment arm with respect to the fulcrum 13 is H₆, H₇age
And consider the balance of the moment about the pivot point 13
And R = (W · H_Four+ W₀・ H_Five-Q ・ H ₆) / H₇When
And the tension Q of the horizontal holding rope 24
It will act to reduce the required tension R.
Therefore, the second sheave 22 is positioned behind the pivot 14.
Has an adverse effect on the undulating rope 18.
There is nothing like that.

[0035]

As can be easily understood from the above description, the mid-bend type bridge crane of the present invention is designed such that the tip boom portion has a special shape having an extension projecting from the base end thereof. By providing the second sheave in this extension, the moment around the connection point between the two boom parts due to the tension of the first and second rope paths can be made larger than in the conventional crane. It is possible to sufficiently cope with an increase in the size of a crane having a long end boom portion without causing a problem such as applying excessive tension, and the practical value thereof is extremely large.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a center-bend type bridge crane according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a detailed view of an upright state in which a main part of FIG. 1 is enlarged.

FIG. 4 is an operation explanatory view corresponding to FIG. 3 and showing a relationship between a tension acting on a boom portion and a load.

FIG. 5 is a perspective view showing a rope holding form of a horizontal holding rope.

6 is a perspective view corresponding to FIG. 5, showing a rope hanging mode different from that of FIG. 5;

FIG. 7 is a perspective view corresponding to FIG. 5, showing a rope hanging mode different from FIGS. 5 and 6;

FIG. 8 is a schematic side view showing a cargo handling device.

FIG. 9 is a schematic side view showing a rope receiving device.

FIG. 10 is a side view of a main part showing a conventional crane.

[Explanation of symbols]

1 ... Bent type bridge crane, 3 ... Boom, 9 ... Girder,
9a: distal end of girder, 10: support body, 11: proximal end boom portion, 11a: distal end of proximal end boom portion, 11b: proximal end of proximal end boom portion, 11c: concave portion, 12: distal end boom portion, 12b: base end of the tip boom portion, 12c: extension, 21 ... first sheave, 22 ... second sheave, 23 ...
Third sheave, 24 ... horizontal holding rope, 24 ₁ ... first rope path, 24 ₂ ... second rope path.

[Procedure amendment]

[Submission date] June 2, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004] Recently, the tendency of large-sized bridge cranes to increase in size has been remarkable due to the increase in the size of container ships, and the length and height of the girder and boom (height from the ground;
Below) is much larger than before. On the other hand, the height of the distal end boom portion 12 when the base end boom portion 11 is located at the upright position cannot be made higher than a certain value due to avoidance of contact with an aircraft or the like. Height). For this reason,
The length of the proximal end boom portion 11, which determines the height of the distal end boom portion 12 (boom upper limit height), is greatly restricted in conjunction with the height of the girder, As a result, as the size of the crane increases, the tip boom portion 12 inevitably tends to be longer, and its weight tends to increase. Therefore, in the case of a recently bent-type bridge-type crane, which tends to become larger, there is a problem that a necessary rope tension is greatly increased, and the fact is that a solution is strongly demanded.

Claims (1)

[Claims] 1. A base boom portion having a base end connected to a tip end of a girder such that the base end is rotatable vertically between a falling position and an upright position, and a vertical rotation relative to a tip end of the base boom portion. A first boom provided on the proximal boom portion and a second sheave provided on the distal boom portion.
When the base end boom portion is located at the lying position and the upright position by the fixed length horizontal holding rope having the rope route and the second rope route wound around the second sheave and the third sheave provided on the girder side. In the middle crane type bridge crane configured to hold the tip boom portion in a horizontal state, the tip boom portion is configured to have an extended portion projecting from the base end in the girder direction, A concave portion is formed in the base end boom portion so that the extended portion can be protruded and retracted without interfering with the up-and-down operation by the vertical rotation thereof, and the second sheave is provided in the extended portion. Folding bridge crane.