JP2756466B2 - Method for controlling lifting posture of curved plate and hanging tool for curved plate - Google Patents

Description

The present invention relates to a method of lifting a curved plate such as a concrete segment by a crane and controlling the lifting posture thereof, and a method suitable for use in carrying out the method. The present invention relates to a curved version of a hanging tool.

"Prior art and its problems" A segment P made of precast concrete used for constructing a tunnel or the like generally has a curved shape matching the cross-sectional shape of the tunnel or the like as shown in FIG.

By the way, since such a concrete segment P is heavy, a crane is used for installing the concrete segment P. In this case, it is usually difficult to lift the segment P from the beginning as the installation posture, and therefore, a general Specifically, it is necessary to lift the segment P in a vertical position or a horizontal position, and then change the position of the segment P to an installation position.

For this reason, conventionally, the posture of the lifting segment P is changed by hanging together using two cranes, changing the wire midway, or using a chain block together. Such work is not only troublesome, but also involves danger, so that sufficient safety measures are required.

The present invention has been made in view of the above circumstances, and is an attitude control method capable of easily changing the attitude of a curved plate such as a concrete segment lifted by a crane, and a method suitable for use in carrying out the method. It is intended to provide a hanging tool.

Means for Solving the Problems According to the invention of claim 1, a curved plate such as a concrete segment is lifted by a crane using a lifting tool having two pulleys around which a wire is wound, and the lifting posture is controlled. A method for setting four suspension points on the surface of the curved plate at each vertex of an imaginary rectangle passing through the center of gravity of the curved plate, and setting the wire to one of the suspension points A first connector to which one end of the wire is connected is attached, a second connector to which the other end of the wire is connected to a hanging point adjacent to the first connector, and the first connector is attached. A first pulley around which the wire is wound and a second pulley around which the wire is wound are attached to a hanging point at a diagonal position with respect to a point and the center of gravity and other hanging points adjacent to the point, respectively. 2 couplers, first and second pulleys One wire is wound around each pulley of the hanging tool in a so-called crossed state. That is, a wire having one end connected to the first connecting member is sequentially wound around one of the pulleys of the hoisting device, the first pulley, the second pulley, and the other pulley of the hoisting device. The other end is connected to the second connector, and a hook of a crane is locked to the second connector to lift the curved plate.

The invention according to claim 2 is a hanging tool used when performing the method for controlling the lifting posture of a curved plate according to claim 1, wherein the wire connected to the curved plate has two windings. A pulley is connected rotatably up and down and around a vertical line, and is configured such that a hook of the crane is locked at an upper end thereof.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 shows an embodiment of a hanger according to the present invention. This hanger 1 comprises two pulleys 2, 2 around which a wire W connected to the curved plate P is wound. It is vertically connected by a pin 3 and has a hook H of the crane at its upper end.
Are locked, and the two pulleys 2 are configured to rotate around a vertical line and change their directions.

In order to lift the segment (curved plate) P as shown in FIG. 10 using the above-mentioned hanging tool 1, four hanging points A are provided on the surface of the segment P as shown in FIGS. , B, C, and D, the two ends of the wire W are connected to the two adjacent suspension points A and D via the shackle 10 as shown in FIG. Eye bolts 11
(First connector), eyebolt 12 (securing the second connector, respectively, and at the other two adjacent suspension points B and C,
A pulley 13 around which the wire W is wound as shown in FIG.
(Second pulley) and pulley 14 (first pulley) are fixed via eyebolts 15, respectively. At this time, eye bolt 11
And the pulley 14 are arranged so that the eye bolt 12 and the pulley 13 are at diagonal positions with respect to the center of gravity of the segment P.

The above-mentioned hanging points A to D are set so as to be located at the respective vertices of a virtual square S (rectangle in the present embodiment) as shown in FIG. As shown in FIG. 3, a virtual plane (centroid plane) p including the center of gravity G of the segment P and bisecting the total weight of the segment is assumed.
What is necessary is just to set the above-mentioned virtual rectangle S so that the virtual intersection line l, l between the segment and the surface of the segment P becomes two sides thereof. Note that the virtual square S is not limited to a rectangle, and may be another square such as a square or a rhombus as long as the center of gravity of the virtual square is set to match the center of gravity G of the segment P.

Then, as shown in the figure, one end of the wire W is connected via a shackle 10 to an eyebolt 11 fixed to a hanging point A, and the wire W is connected to one of the pulleys 2 and 2 of the hanging tool 1 (see FIG. In the example shown, the lower pulley 2), the pulley fixed to the suspension point C
14, the pulley 13 fixed to the hanging point B, and the other of the pulleys 2 and 2 of the hanging tool 1 (upper pulley 2) are sequentially wound around the other end of the wire W to the eye bolt 12 fixed to the hanging point D. connect.

Then, a hook H of a crane is attached to the upper end of the hanging tool 1.
, And the segment P is lifted, the posture of the lifted segment P can be freely changed.

That is, for example, if the segment P lifted in a horizontal posture as shown in FIG. 2 is moved by an input as needed, each pulley 2, 2 of the hanging device 1 rotates in accordance with the moved direction. And their directions change, and the first and second pulleys 14, 13 fixed to the segment P rotate accordingly, whereby the segment P
The posture changes smoothly and stably, for example, it can be changed to the vertical posture as shown in FIG. 8 or the installation posture as shown in FIG. Of course, after lifting in the vertical position shown in FIG.
The horizontal posture shown in FIG. 2 or the installation posture shown in FIG. 9 can be adopted, and vice versa.

Therefore, by performing the above, it is possible to omit the troublesome work of hanging together using two cranes as in the related art, exchanging wires midway, or using a chain block together. Therefore, labor and efficiency of the installation work of the segment P can be reduced, and safety can be secured. Also, in this case, since an equal load is applied to the four hanging points A to D, it is safe at this point, and the segment P
No excessive force is applied to the.

In the above embodiment, the concrete segment is given as an example of the curved plate. However, the present invention is not limited to the concrete segment, but may be applied to other curved plates, such as a steel plate for forming a side wall of a circular tank. Needless to say.

[Effects of the Invention] As described in detail above, the invention of claim 1 sets a suspension point at each vertex of a virtual rectangle passing through the center of gravity of the curved plate, and attaches a wire to an adjacent one of the suspension points. Attach the pulleys to the other suspension points and attach pulleys to the other suspension points, and wrap the wires around those suspension points in a so-called cross-linked state, so that the suspended curved plate can be moved as necessary. By doing so, each pulley of the hanging tool 1 rotates and its direction changes, and the pulley fixed to the curved plate rotates, so that the posture of the lifted curved plate changes smoothly and stably. Therefore, there is an effect that the operation of changing the lifting posture of the curved plate can be performed extremely easily.

Further, since the hanging tool of the invention of claim 2 has a configuration in which the two pulleys are rotatably connected up and down and around a vertical line, when the curved plate lifted by the hanging tool is moved, As the pulleys rotate, their directions change, and therefore, the posture of the curved plate can be smoothly changed, which is suitable for use in performing the above method.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the hanger according to the present invention. 2 to 5 show a state in which the concrete segment is lifted in a horizontal posture by the above-mentioned hanging tool.
2 is a perspective view, FIG. 3 is a front view, FIG. 4 is a side view, and FIG. 5 is a plan view. FIG. 6 is a diagram showing an eyebolt (connector) fixed to the curved plate, and FIG. 7 is a diagram showing a pulley fixed to the curved plate. FIG. 8 is a perspective view showing a state in which the concrete segment lifted by the above-mentioned hanging tool is in a vertical position, and FIG. 9 is a perspective view showing a state in which the concrete segment is also in an installation position. FIG. 10 is a perspective view showing an example of a concrete segment which is an example of a curved plate. DESCRIPTION OF SYMBOLS 1 ... Hanging tool, 2 ... Pulley, 3 ... Pin, 10 ... Shackle, 11 ... Eyebolt (first connecting tool), 12 ... Eyebolt (second connecting tool), 13 ... Second Pulley, 14 ... first pulley, P ... segment (curved version), G ... center of gravity, S ... virtual square, p ... center of gravity plane, AD ... hanging point, W ... wire, H ... hook.

Claims (2)

(57) [Claims] 1. A method for lifting a curved plate such as a concrete segment by a crane using a lifting tool provided with two pulleys around which a wire is wound and controlling the lifting posture thereof, comprising: A first connecting member which is located at each vertex of an imaginary rectangle passing through the center of gravity of the curved plate and sets four suspension points, and one end of the wire is connected to one of the suspension points And a second connecting member to which the other end of the wire is connected to a hanging point adjacent thereto, and at a diagonal position across the center of gravity with the hanging point to which the first connecting member is attached. A first pulley and a second pulley around which the wire is wound are respectively attached to a certain hanging point and another hanging point adjacent thereto, and a wire having one end connected to the first connector is attached to the hanging point. Any of the pulleys, the first The pulley, the second pulley, and the other pulley are sequentially wound around the pulley, and the other end is connected to the second connector, and a hook of a crane is locked to the hook to lift the curved plate. A method of controlling a lifting posture of a curved plate. 2. A hanging tool for use in carrying out the method for controlling a lifting posture of a curved plate according to claim 1, wherein two pulleys around which wires connected to the curved plate are wound are arranged vertically. And a hook connected to the crane at an upper end thereof so as to be rotatable about a vertical line, and the hook of the crane is locked at the upper end thereof.