JPH11157782A - Tower crane, its backstop device, and method for operating tower crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the operational range of a tower crane by making the minimum operating radius of the tower crane smaller than those of tower cranes of the prior art although the tower crane has a long-size jib. SOLUTION: In a tower crane 1 in which a boom is raised and lowered relative to a base machine by a boom-derricking guy line 8 while a jib 5 provided at the end of the boom 4 is raised and lowered by a jib-derricking guy line 9, with the maximum raised angle of the boom 4 limited by a backstop device 10, the maximum raised angle of the boom 4 is permitted up to a backwardly-inclined position where the maximum raised angle is greater than the vertical.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tower crane, and more particularly, to a tower crane in which a boom is fixed in an upright state and only a jib is raised and lowered to perform a lifting operation, and both a boom and a jib are raised and lowered to perform a lifting operation. The present invention relates to a tower crane such as a luffing crane, its backstop device, and a method of operating the tower crane.

[0002]

2. Description of the Related Art Conventionally, a crawler crane as a mobile tower crane has a traveling body using a crawler, and a revolving body rotatably mounted on the traveling body. Has a boom that can be raised and lowered, and a jib is further mounted at the tip of the boom so that it can be raised and lowered. When performing a lifting operation with this type of tower crane, the boom angle can be adjusted by winding or unwinding a boom hoisting guy line that is led out through a gantry from a boom winch equipped on the revolving structure, The jib angle can be adjusted by winding or unwinding the jib hoisting guy line derived from the jib winch.

[0003] A backstop device is connected between a support portion provided at the upper portion of the revolving superstructure and a rear wall near the lower portion of the boom. This backstop device is usually composed of a pair of pipes that are slidably fitted, and can expand and contract with the rise and fall of the boom. It is designed to prevent falling backwards. In a tower crane having such a configuration, the boom angle is usually operated in a vertical posture or a forwardly inclined posture during a lifting operation.

[0004]

In the tower crane described above, the minimum working radius in a state where the boom is standing upright is determined by the jib angle at the time of the maximum undulation.
Therefore, in the current situation where the jib tends to be longer,
There is a problem that the load at the foot of the tower crane cannot be lifted. In particular, in an urban area, since a hanging operation in a narrow working environment is forced, if the minimum working radius is small, the hanging operation is restricted. Accordingly, there is a need for a tower crane having a small minimum working radius in addition to being able to suspend a distant load by providing a long jib. The present invention has been made in consideration of the problems of the conventional tower crane as described above, and has a minimum work radius smaller than that of the conventional tower crane to increase the work range while having a long jib. To provide a tower crane, a backstop device for the same, and a method of operating the tower crane.

[0005]

According to a first tower crane according to the present invention, a boom is raised and lowered with respect to a base machine by a boom raising and lowering guy line, and a jib provided at the end of the boom is raised and lowered by a jib raising and lowering guy line. In a tower crane that suspends a suspended load from the end of a jib, it is essential that the boom is configured to be able to tilt backward from a vertical line in a state where the suspended load is suspended.

Further, in the second tower crane according to the present invention, the boom is raised and lowered with respect to the base machine by the boom raising and lowering guy line, and the jib provided at the end of the boom is raised and lowered by the jib raising and lowering guy line, so that the boom is upright. In a tower crane whose angle is regulated by the backstop device, the gist of the present invention is that the backstop device is configured such that the maximum rising angle of the boom is allowed to a rearwardly inclined posture that is larger than vertical.

[0007] In the second tower crane, the backstop device comprises a pair of slidably fitted tubular members that expand and contract with the up and down movement of the boom, and the distance between the end of the tubular member and the boom. It is preferable to have an adjusting mechanism for adjusting the distance between the end of the cylindrical member and the base machine.

The adjusting mechanism includes a shaft member extending from the end of the cylindrical member in the cylinder axis direction, a shaft guide provided along the shaft member for guiding the shaft member, and a shaft member provided in the axial direction. It can be composed of one of a plurality of through holes provided at predetermined intervals and a pin inserted into the shaft guide.

The adjusting mechanism includes a shaft member extending from the end of the cylindrical member in the cylinder axis direction, a shaft guide provided along the shaft member for guiding the shaft member, and a shaft provided on the shaft guide. A locking piece locked or released from one of the plurality of locking grooves provided at predetermined intervals in the axial direction of the member.

A backstop device according to the present invention is a backstop device for restricting a maximum rising angle of a boom of a tower crane, comprising a pair of slidably fitted cylindrical members which extend and contract with the boom up and down. The gist comprises a member and an adjusting mechanism for adjusting the distance between the end of the tubular member and the boom or the distance between the end of the tubular member and the base machine.

Further, in the operation method of the tower crane according to the present invention, the boom is raised and lowered with respect to the base machine by the boom raising and lowering guy line, and the jib provided at the tip of the boom is raised and lowered by the jib raising and lowering guy line. In the method of operating a tower crane that suspends suspended loads from the part, (a) suspend the suspended load at a position away from the base machine while the boom is tilted vertically or forward, and (b) raise the maximum standing angle of the boom from the vertical. The jib swinging fulcrum toward the base machine,
(c) Lower the suspended load near the base machine, or suspend the suspended load near the base machine by performing the above steps (a) to (c) in reverse, and suspend the suspended load at a position away from the base machine. The gist is to bring down.

According to the tower crane and the method of operating the same according to the present invention, when the maximum upright angle of the boom is tilted to a rearwardly inclined posture that is larger than vertical, the pivot point of the jib moves to the base machine side. The working radius is reduced, which allows hanging work near the base machine.

According to the backstop device of the present invention, since the connection distance between the base machine and the boom in the tower crane can be adjusted, the maximum upright angle of the boom can be changed from the forward inclined position to the backward inclined position which becomes larger than the vertical. You can change your posture.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 shows an external configuration of a tower crane according to an embodiment of the present invention.

In FIG. 1, a tower crane 1 has a traveling body 2 as a base machine and a revolving body 3 rotatably mounted on the traveling body 2, and a boom 4 is attached to a front portion of the revolving body 3. A jib 5 is further attached to the end of the boom 4. A gantry 6 is provided at the rear of the revolving unit 3, and a counterweight 7 is mounted at the rear end.

The boom 4 is raised and lowered by a boom raising and lowering guy line 8 which is stretched and loosened by a boom winch (not shown) mounted on the revolving unit 3. The jib is raised and lowered by a jib hoisting guy line 9 which is stretched and loosened by an equipped jib winch (not shown).

A backstop device 10 is connected between the upper part of the revolving unit 3 and the position of the boom 4 below the boom 4. As shown in the enlarged view of the main part of FIG. 2, the backstop device 10 has a structure that can be extended and contracted so that the connection is maintained when the boom 4 is upright or down. More specifically, the backstop device 10 includes an inner tube 10a and an outer tube 10b as a pair of slidably fitted cylindrical members, and an adjusting mechanism 11 for adjusting a distance between the inner tube 10a and the upper part of the revolving unit 3. And In the drawing, reference numeral 12 denotes a compression coil spring mounted on the body of the inner tube 10a, which is the same as the conventional configuration.

As shown in FIG. 3, the adjusting mechanism 11 includes a shaft (shaft member) 11a extending from the end of the inner tube 10a in the cylinder axis direction and a shaft guide for slidably housing the shaft 11a. 11b and a fixing pin (pin) 11d which is arranged at equal intervals along the axis 11a and is inserted into any of a plurality of through holes 11c formed in the diameter direction. Reference numeral 11e is a split pin attached to the tip of the fixing pin 11d as a retaining pin. A mounting bracket 11 for fixing the backstop device 10 to the upper part of the revolving unit 3 is provided at an end of the shaft guide 11b.
f is formed.

FIG. 3 shows a state in which the shaft 11a is inserted to the deepest position in the shaft guide 11b, whereby the maximum upright angle of the boom 4 is reduced to the vertical line VL.
(See FIG. 1). The tower crane having such a configuration operates as follows.

In the case of performing a hanging operation using a tower crane, when there is a restriction that the working environment is narrow,
First, before the boom 4 is triggered, the backstop device 1
The zero adjustment mechanism 11 is adjusted. Specifically, the shaft guide 1
1b, the insertion depth of the shaft 11a is adjusted,
By inserting 1d, a desired backward tilt posture is obtained.

In FIG. 1, for example, if the length of the boom 4 is 5
In a conventional tower crane having a 6.69 m length and a jib length of 42.67 m, the minimum working radius r ₁ when the hook is extended from the jib 5 and the lifting operation is performed with the boom 4 standing upright is 14. .27 m. On the other hand, in the tower crane of the present invention, since the boom 4 can be tilted to the rear of 5 ° where the maximum standing angle is larger than the vertical, the minimum working radius r ₂ is 5.69 m. Therefore, the minimum working radius can be reduced by about 9 m.

The backward inclination angle of the boom 4 is determined by the position of the center of gravity determined according to the length of the boom 4 and the jib 5 and their weight. The position of the center of gravity only needs to be within the allowable limit of the rearward stability of the fuselage, and in the case of the embodiment of FIG. However, if the minimum working radius can be reduced to just before the traveling body, the object of the present invention will be achieved.

When the jib 5 is long, the moment forward is large, so that the boom can be tilted backward. On the other hand, when the jib is short, the forward moment is small, and it is dangerous to tilt the boom 4 backward.
Therefore, it is necessary to set the backward tilt angle of the boom 4 according to the boom, the jib, and the angle at which the jib is operated on the tower crane. However, the practical backward tilt angle is
The angle is set to a slightly forward tilt angle from the backward tilt angle calculated in consideration of the safety factor.

FIG. 4 shows a second embodiment of the present invention. In the following description, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, an adjusting mechanism 13 includes a shaft (shaft member) 13a extending from an end of the inner tube 10a.
And a shaft guide 13b for slidably storing the shaft 13a.
And a plurality of locking grooves 13c formed at equal intervals on the shaft 13a
And a latch (locking piece) 13d locked to any one of the above. The latch 13d is urged in the direction of arrow C by a compression coil spring 13e. When the latch 13d is pulled away from the shaft 13a against the urging force of the spring 13e, the latch 13d
Can be detached from the locking groove 13c. FIG. 4 shows a state in which the shaft 13a is inserted to the deepest position in the shaft guide 13b, whereby the maximum rising angle of the boom 4 is 5 ° behind the vertical line VL (see FIG. 1). Will be inclined.

FIG. 5 uses a cylinder 14 and an accumulator 15 instead of the compression coil spring 12 mounted on the inner tube 10a. In this configuration, the end of the inner tube 10a is
It functions as a piston 4c that slides inside. That is, as the boom 4 assumes the backward tilted posture, the outer tube 10b first moves in the direction of arrow D, and then the inner tube 10a is brought into contact with the end of the inner tube 10a opposite to the piston 4c.
Is moved in the direction of arrow D.

When the piston 4c of the inner tube 10a is pushed in the direction of arrow D, the oil in the cylinder 14 is drawn out from the oil port 14a and injected into the accumulator 15. At this time, even if the movement of the inner tube 10a (backward tilting of the boom 4) is performed by impact, the accumulator 1
The gas in 5 can be compressed to absorb the pulsation of piston 4c. Thereby, the vibration of the boom 4 is suppressed,
Safe hanging work can be realized.

In the above-described embodiment, the maximum backward inclination angle (maximum standing angle) is regulated by the backstop. However, the present invention is not limited to this. For example, a mechanical stopper may be provided separately from the backstop. Regulations can also be made using other means. In addition, mechanical stopper
It is desirable to add a shock absorbing member.

FIGS. 6 to 8 show the types of suspension work that can be performed by the operation method of the tower crane of the present invention. First, FIG. 6 shows a case where a suspended load is drawn toward the crane at the upper part of the building 16. That is, in FIG. 3A, the boom 4 is in a substantially upright state, and lifts the load in the direction of the arrow E, and then raises the jib 5. In FIG. 5B, when the raising of the jib 5 is completed, the boom 4 is tilted backward in the arrow G direction. FIG. 4C shows a state in which the load is lowered after the boom 4 is tilted rearward at the rearward tilt angle 5 °. This allows the load to be pulled to the edge of the building.

FIG. 7 shows a case where a load is unloaded on the bed of the vehicle 17 in a state where a vehicle passage is secured between the building 16 and the tower crane. In FIG. 3A, the boom 4 is in a substantially upright state, and lifts the load in the direction of arrow E, and then raises the jib 5. In FIG.
When the raising of the jib 5 is completed, the boom 4 is moved to the arrow G.
Lean backward. FIG. 3C shows the vehicle 1 placed near the tower crane by tilting the boom 4 backward at a backward tilt angle of 5 ° and then unwinding the jib hoisting guy line 9.
7 can be unloaded on the loading platform.

FIG. 8 shows a case where a load is unloaded near the tower crane in a state where a vehicle passage cannot be secured between the building 16 and the tower crane. In FIG. 3A, the boom 4 is in a substantially upright state, and lifts the load in the direction of arrow E, and then raises the jib 5. In FIG. 5B, when the raising of the jib 5 is completed, the boom 4 is tilted backward in the arrow G direction. FIG. 3 (c) shows that after the boom 4 is tilted backward at a backward tilt angle of 5 °, the revolving unit 3 is rotated by 180 ° and the guy line 9 for raising and lowering the jib is unwound to unload the load near the tower crane. Can be.

Although FIGS. 6 to 8 all describe the case where the suspended load is lowered, it goes without saying that the suspended load can be lifted by the reverse procedure. Also,
6 to 8, the jib is caused first, but the boom may be caused first.

Although the tower crane of the present invention is a crawler crane in the above embodiment, the present invention is not limited to this, and the present invention can be applied to a mobile crane such as a wheel crane.

The adjusting mechanism of the present invention is provided at the end of the inner tube 10a in the above embodiment, but is not limited to this, and may be provided at the end of the outer tube 10b to adjust the distance from the boom 4. , It is possible to realize a backward leaning posture.

[0035]

As is apparent from the above description,
According to the tower crane of the present invention and the method of operating the tower crane, the maximum standing angle of the boom is tilted to a rearwardly inclined posture that is larger than the vertical, and the jib rotation fulcrum is moved to the base machine side. The working radius can be made smaller than that of the conventional tower crane, and the working range can be expanded.

According to the backstop device of the present invention, since the connection distance between the base machine and the boom in the tower crane can be adjusted, the maximum upright angle of the boom can be changed from the forward inclined position to the backward inclined position which becomes larger than the vertical. You can change your posture.

[Brief description of the drawings]

FIG. 1 is an external configuration diagram showing a rearwardly inclined posture by a tower crane of the present invention.

FIG. 2 is an operation explanatory diagram of the backstop device shown in FIG. 1;

FIG. 3 is an enlarged view of the backstop device according to the present invention with a partial cutout.

FIG. 4 is a view corresponding to FIG. 3, showing a second embodiment of the backstop device according to the present invention.

FIG. 5 is a diagram corresponding to FIG. 3, showing a third embodiment of the backstop device according to the present invention.

FIG. 6 is an explanatory diagram showing an operation method using the tower crane of the present invention.

FIG. 7 is an explanatory diagram showing an operation method using the tower crane of the present invention.

FIG. 8 is an explanatory diagram showing an operation method using the tower crane of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tower crane 2 Traveling body 3 Revolving structure 4 Boom 5 Jib 8 Guy line for boom raising and lowering 9 Guy line for jib raising and lowering 10 Back stop device 10a Inner tube 10b Outer tube 11 Adjusting mechanism 11d Fixing pin

Claims (7)

[Claims] 1. A tower crane in which a boom is raised and lowered with respect to a base machine by a boom raising and lowering guide line, a jib provided at a tip of the boom is raised and lowered by a jib raising and lowering guy line, and a suspended load is hung from the tip of the jib. A tower crane, wherein the boom is configured to be able to tilt backward from a vertical line with a suspended load. 2. The boom is raised and lowered with respect to a base machine by a boom raising and lowering guide line, a jib provided at a tip of the boom is raised and lowered by a jib raising and lowering guide line, and a maximum rising angle of the boom is regulated by a backstop device. The tower crane according to claim 1, wherein the back stop device is configured such that a maximum upright angle of the boom is allowed to a rearwardly inclined posture that is larger than vertical. 3. A backstop device comprising: a pair of slidably fitted tubular members that expand and contract with the up and down movement of a boom; and a distance between the tubular member end and the boom or a tubular member end. An adjustment mechanism for adjusting the distance between the unit and the base machine;
The tower crane according to claim 2, comprising: 4. An adjusting mechanism comprising: a shaft member extending in an axial direction from a cylindrical member end; a shaft guide provided along the shaft member for guiding the shaft member; 4. The tower crane according to claim 2, comprising one of a plurality of through holes provided at a predetermined interval in an axial direction and a pin inserted into the shaft guide. 5. 5. An adjusting mechanism comprising: a shaft member extending in an axial direction from an end of the cylindrical member; a shaft guide provided along the shaft member for guiding the shaft member; 3. A locking piece which is provided and is locked or released from one of a plurality of locking grooves provided at predetermined intervals in an axial direction of the shaft member. Or the tower crane according to 3. 6. A backstop device for restricting a maximum rising angle of a boom of a tower crane, comprising: a pair of slidably fitted tubular members which expand and contract with the rise and fall of the boom; A backstop device comprising: an adjusting mechanism that adjusts a distance between the base member and the boom or a distance between the end of the cylindrical member and the base machine. 7. A boom is raised and lowered with respect to a base machine by a boom raising and lowering guy line, and a jib provided at a tip of the boom is raised and lowered by a jib raising and lowering guy line.
In the method of operating a tower crane that suspends a suspended load from the tip of a jib, (a) suspending a suspended load at a position away from the base machine in a state where the boom is tilted vertically or forward,
(b) tilting the maximum upright angle of the boom to a rearwardly inclined posture that is larger than vertical to pull the swing fulcrum of the jib toward the base machine, and (c) unload the suspended load at a position near the base machine. Or operating the tower crane, wherein the steps (a) to (c) are reversed to suspend the suspended load near the base machine and drop the suspended load away from the base machine. Method.