JPS6140811B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for assembling legs of a landing lift type offshore work platform. More specifically, it is possible to accurately match the pitch of the racks of the legs assembled with a cord consisting of two semi-cylindrical cord materials, an intermediate plate, and two racks provided on both sides of the intermediate plate. A method of assembling the legs is provided.

A landing lift type offshore work platform usually has a plurality of polygonal legs with three or four cords connected by connecting rods, and a jacking device is installed on the workbench to control the jacking. The device is configured to engage the racks of the legs and move the workbench up and down along the legs. This jacking device consists of a motor, a speed reducer, and a pinion that is the output end of this speed reducer, and this pinion must mesh accurately with the racks extending on both sides of the cord that makes up the leg. Must be.

On the other hand, since the workbench is used in places where the water depth is 70m or more, the total length of the legs is 80 to 110m. Since it is extremely difficult to accurately assemble such a long leg, unit legs of about 5 to 20 m are manufactured and then welded to form the unit legs to the above length.

By the way, it is extremely difficult to accurately match the pitch of the racks installed on the sides of the long legs, which are 110 meters long. There is a problem in that the work table cannot be smoothly raised and lowered due to the inability to transmit the information.

To explain the above-mentioned problem in more detail, pinions are engaged in multiple stages with the racks provided on both sides of one cord, and these pinions are usually six in number.
The number is 1 to 8. According to the inventors' measurements, the footings provided at the lower ends of the legs are placed on the bottom, and the jacking device is activated to raise the workbench to a predetermined height and maintain a constant torque acting on each pinion. Even if these pinions are fixed, the torque may fluctuate due to an external force such as a storm. Also, if there are variations in rack pitch, straightness, etc., some pinions may exceed the allowable torque range, so if you design the power transmission system with this in mind, the jacking device will be quite large, and The drawback was that manufacturing costs increased significantly.

As mentioned above, there are various problems in manufacturing the cords that make up the legs, and how accurately the legs are manufactured is important in determining the performance of a landing lift type offshore work platform.

The present invention aims to solve the problems of the above-mentioned prior art, and the present invention provides an intermediate plate, racks provided on both sides of the intermediate plate, and a semi-cylindrical structure connecting the racks. In the method of assembling the legs of a landing lift type offshore work platform having a cord made of cord material, the support plate for the upper cord 4b is placed on the horizontal plate 10, which is the positioning member for the lower cord 4a, and in this state After aligning the intermediate plates 6a and 6b and the racks 7a and 7b, the intermediate plates 6a and 6b are aligned.
and 6b, and the racks 7a and 7b are respectively welded.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the main parts of a landing lifting type offshore work platform. This jacking device 2 is operated to move the workbench 1 up and down along the legs 3.

FIG. 2 is a plan view of the leg portion 3 and the jacking device 2. The leg portion 3 has three cords 4 connected by a connecting rod 5 to form a triangular tower shape as a whole. As will be described later, racks are provided on both sides of this cord, and the pinion of the jacking device 2 is engaged with the racks.

Figures 3 and 4 are diagrams showing the upper structure of code 4 (even if the same members constitute the same code, the upper structure is indicated with a and the lower structure is indicated with b). Rack 7a is welded to both sides of intermediate plate 6a, and a semi-cylindrical cord 8a is welded to connect both racks 7a. This cord material 8a
is slightly shorter than the length of the rack 7a, and a distance L is provided between them. Further, the intermediate plate 6
Two support plates 9a are radially welded to both sides of a, and a horizontal plate 10 is provided above the support plates 9a.

4 and 8 show a situation in which the horizontal plate 10 supported by the support plate 9a is provided on the same plane as the rack 7a. Figures 6 and 7 are
In the figure showing the lower structure of the cord 4, two supporting plates 9b are provided radially on both sides of the intermediate plate 6b. This support plate 9b is similar to the upper structure of the cord 4 shown in FIGS. 3 and 4, except that the horizontal plate 10 is omitted.

Next, the situation in which the cord 4 is connected according to the present invention will be explained.

As shown in Figure 8, the code 4b is attached to the top of the code 4a.
The support plate 9b of the cord 4b is positioned on the horizontal plate 10, and the racks 7a and 7b of the cords 4a and 4b and the intermediate plates 6a and 6b are aligned. For this positioning, a positioning member 11 (FIG. 10) extending from the support plate 9a is used.

After the alignment of intermediate plates 6a and 6b shown in circle A in Fig. 10 and the alignment of racks 7a and 7b shown in circle B in Fig. 11 is completed, these alignment parts are welded. . The reason why a distance of 2L is provided between the semi-cylindrical cord members 8a and 8b is to perform the above-mentioned welding, and this distance 2L is preferably selected based on the size of the cords and ease of welding work.

Now, the intermediate plates 6a, 6b and the racks 7a, 7b
Once welded, parts of the support plates 6a and 6b and the horizontal plate 10 are removed by cutting the portion shown by the double-dot chain line C in FIG.

Then, the open portions of the cord materials 8a and 8b are closed with another semi-cylindrical plate.

Note that if it is better to connect the support plates 9a and 9b, the support plate from which the horizontal plate 10 has been removed may be welded back to its original position.

As described in detail above, the present invention provides the support plate 9a and the horizontal plate 10 as positioning members on the upper part of the cord 4, and furthermore, the upper end of the cord material 8a is made shorter than the upper part of the rack 7a to leave a gap. , a support plate 9b is provided on the intermediate plate 6b as a positioning member for the lower part of the cord, and the cord 8b is shortened,
This is characterized by the support plate 9b facing here.

Therefore, according to the present invention, the support plate for the upper cord 4b is placed on the horizontal plate 10, which is a positioning member for the lower cord 4a, and in this state, the intermediate plates 6a, 6b and the racks 7a, 7b are aligned. After doing this and welding the support plate 9b and the horizontal plate 10 as necessary, the intermediate plate and the rack are welded, so that the pitch and direction of the rack can be accurately maintained.

When the welding of the racks 7a, 7b, etc. is completed as described above, the opening required for this welding work is closed with a semi-cylindrical plate similar to another cord material, and the welding of one cord is completed. . One leg 3 is the second
As shown in the figure, since three cords 4 are provided, the welding operation of the cords is repeated to complete the connection of one leg 3.

In the present invention, since the racks and the like are aligned using the positioning member as described above, the preparation work for welding the legs is easy, and the pitch and direction of the racks can be adjusted accurately.

By joining the legs according to the present invention,
It is possible to easily connect the legs, and as a result, the assembly work of the landing lift type offshore work platform can be carried out smoothly.

Further, according to the present invention, since the direction and pitch of the rack are accurately determined, the torque acting on the pinion of the jacking device 2 that meshes with the rack is accurately distributed, so that the landing lift type offshore work platform can be safely operated. can be operated.

[Brief explanation of the drawing]

FIG. 1 is a side view of the main parts showing the legs of the landing lift type offshore work platform. FIG. 2 is a plan view showing the engaged state of the leg and the jacking device. 3 and 4 are a front view and a side view showing the upper structure of the cord. FIG. 5 is a plan view of the upper structure of the cord. 6 and 7 are a front view and a side view showing the lower structure of the cord. FIG. 8 is a perspective view showing a state of preparation immediately before connecting the cord. FIG. 9 is a front view showing a state in which two cords are connected. FIG. 10 is a side sectional view showing the positioning state of the intermediate plate of the two cords. FIG. 11 is a side sectional view showing the positioning state of the rack. 1... Workbench, 2... Jacketing device, 3... Legs, 4
... Cord, 5... Connecting rod, 6a, 6b... Intermediate plate, 7
a, 7b...Rack, 8a, 8b...Cord material, 9
a, 9b...Support plate, 10...Horizontal plate.

Claims (1)

[Claims] 1. An intermediate plate, racks provided on both sides of the plate,
In the method for assembling a leg portion having a cord made of semi-cylindrical cord material connecting between the racks, a support plate for the upper cord 4b is placed on a horizontal plate 10 which is a positioning member for the lower cord 4a. The legs of the landing elevating type offshore work platform are arranged such that after the intermediate plates 6a and 6b and the racks 7a and 7b are aligned in this state, the intermediate plates 6a and 6b and the racks 7a and 7b are welded, respectively. How to assemble the parts.