JPS5920422Y2 - Leg fixing device for elevating offshore work platform - Google Patents

Description

[Detailed description of the invention] The present invention has a workbench and a support leg (rig) supported by the workbench so that it can be raised and lowered relative to the workbench, and the support state is maintained between the workbench and the support leg. This invention relates to a leg fixing device for a lifting-type offshore work platform (rig) obtained through a lifting mechanism.

The above-mentioned type of elevating offshore work platform is exposed to different and severe external forces during sea transportation to the test drilling area after construction, during sea transportation to change the test drilling area, and during operation in the test drilling area. It will be done.

If we refer to the former as maritime transport conditions and the latter as sea conditions, the life of an elevating offshore work platform is almost always under sea conditions, and little thought is given to operating the same work platform under significantly different sea conditions. On the other hand, maritime transport situations do not occur very often.

Therefore, the design of elevating offshore work platforms and their elevating mechanisms is usually based on sea conditions, and it is not a good idea to use maritime transportation conditions as a standard.

However, maritime transport conditions present special problems that do not arise under sea conditions.

As schematically shown in FIGS. 1a and 1), the elevating type offshore work platform has a work platform 1 and support legs 2 supported by the work platform 1 so as to be able to rise and fall relative to the work platform 1. The state is obtained via a lifting mechanism 3 interposed between the two.

Sea transportation of such an elevating type offshore work platform is carried out by raising the support leg 2 to the upper limit or near the upper limit relative to the work platform 1, as shown in the figure. towers over the workbench 1, placing a heavy burden on the elevating mechanism 3 that supports it.

In other words, as shown in FIG. 2, when the workbench 1 is shaken by waves or the like in the state shown in FIG. Specifically, a large bending moment M (see Fig. 1 a, b) will occur.

Conventionally, leg guides 4A and 4B are provided at the upper and lower parts of the lifting mechanism 3, respectively, so the bending moment M is equal to the horizontal forces H1 and H generated on the leg guides 4A and 4B.
2 and the vertical force generated at the support point of the lifting mechanism 3.

However, as mentioned above, the elevating type offshore work platform is designed based on the sea state rather than the maritime transport state, so the vertical force generated at the support point P during the maritime transport state exceeds the vertical force holding capacity of the elevating mechanism 3. It is often exceeded.

If a pinion rack type is adopted as the elevating mechanism 3, the vertical force holding capacity of the pinion 3A is exceeded.

Even under such a situation, the pinion 3A
, it is impossible to release the brake state, and it is impossible to eliminate the burden of the vertical force caused by the bending moment l-M generated on the pinion 3A.

Further, although the support leg 2 is made up of a plurality of tubular cords, the strength of the cords itself may not be maintained due to the bending moment (M).

The present invention has been made in view of the above circumstances, and examples thereof will be described below.

In FIGS. 3 to 6, reference numeral 5 indicates a workbench, and reference numeral 6 indicates its supporting legs.

The support leg 6 is constructed by framing three tubular cords 6A with a press 6B or the like.

A support leg insertion hole 7 is formed in the workbench 5, and a lifting mechanism 8 is installed above the support leg insertion hole 7.

The lifting mechanism 8 includes a rack (
Not shown.

), and by rotating these pinions 8A in the forward or reverse direction, the support leg 6 can be raised and lowered relative to the workbench 5 through the insertion hole 7. .

A spud can 9 for seating on the seabed is provided at the lower end of the support leg 6, and the top of the housing of the elevating mechanism 8 and the workbench 5 are provided.
Leg guide IOA at the bottom of each.

10B, spacer 11, etc. are provided.

During sea transportation, the support legs 6 are raised to the upper limit or near the upper limit relative to the work platform 5, but at that time,
The lower end of the support leg 6 and the workbench 5 are connected to each other so as not to allow relative displacement of the two in the relative up-and-down direction.

In FIGS. 5 and 6, a fixing device 12 for this purpose is provided between the support leg 6 and the support leg insertion hole wall 7A of the workbench 5.

In this state, the elevating offshore work platform is either towed with the work platform 5 floating directly on the ocean as shown in FIG.

As described above, if the lower end of the support leg 6 is connected to the workbench 5 in such a manner that relative displacement between the two is not allowed during sea transportation, the braking state of the pinion 8A cannot be released, so the pinion 8A said bending moment) M
That is, the vertical force (see FIG. 2) is supported by the workbench 5 via the fixing device 12.

Therefore, the situation where the elevating mechanism 8 designed based on the sea state has to support the excess load is improved.

This means that most of the load of the bending moment M is supported by the vertical supporting force of the fixing device 12, so the horizontal forces H1 and H2 borne by the leg guides IOA and IOB are relatively small. This is of great practical benefit in terms of the design of the support leg 6.

The type of fixing device 12 is determined by focusing on its strength, taking into account the operability of attachment and detachment, the functionality of raising and lowering the support leg 6 in the test drilling area, and the like.

7 and 8 take into consideration not only the strength but also the operability of attaching and detaching, the functionality of lifting and lowering the support leg 6, and the reusability.

That is, the thick plates 13A and 1 are placed opposite to each other on the wall of the support leg insertion hole 7A of the workbench 5 and the wall of the tubular cord 6A.
3B are fixed and protruded by welding 14A and 14B in the vertical direction.

These pair of plate materials 13A, 13B have teeth 15A, 15B on their tip edges, respectively.

The teeth 15A and 15B extend in the relative lifting direction (vertical direction) between the workbench 5 and the support leg 6, and in the illustrated example, the pitches of the teeth are equal.

Opposing teeth 15A, 15B of a pair of plate materials 13A, 13B
An insertion plate 16 is inserted between them.

The insertion plate 16 has teeth 17A having the same shape and the same pitch as the teeth 15A and 15B so that the insertion plate 16 can be fitted and removed between the teeth 15A and 15B that face each other only in the thickness direction of the plates 13A and 13B. , 17B on each side edge in the width direction.

It is divided in the middle to facilitate its insertion and removal.

Covers 18A are provided on both sides of the insertion plate 16 to prevent the insertion plate 16 from falling out of plane when the insertion plate 16 is fitted between opposing teeth.
, 18B are provided.

In other words, the covers 18A and 18B are a pair of plates 13A.
, 13B, and is fixed to the plates 13A, 13B at appropriate positions with bolts 19 or the like.

In this case, the plates 13A, 13B and the insertion plate 16 act as strength members, and the covers 18A, 18B and the bolts 19 merely serve to prevent the insertion plate from falling off.

According to such a device, since the weight of the support leg 6 acts on the plate material 13A on the workbench 5 side via the plate material 13B on the support leg 6 side and the insertion plate 16, the above-mentioned vertical force (2) is applied to the work surface. The burden is borne by 5 units.

Relative lifting and lowering of the workbench 5 and the support legs 6 in the test drilling area etc. is performed with the covers 18A, 18B and the insertion plate 16 removed.

As is clear from the above explanation, the present invention prevents excessive loads from being applied to the lifting mechanism and from increasing the supporting force borne by the leg guides even under special conditions during maritime transportation. This eliminates the need to design an elevating offshore work platform based on maritime transportation conditions that only occur temporarily, and effectively allows the design to be based on sea conditions that govern most of its life. You will get it.

[Brief explanation of the drawing]

Figures 1a, b and 2 are explanatory diagrams of conventional examples, and Figures 3 to 1.
Figure 0 shows an embodiment of the present invention, Figures 3 a and 1) are explanatory views, Figure 4 is a plan view, Figure 5 is a schematic sectional view, and Figure 6 is a cross section taken along line A-A in Figure 5. 7 is a longitudinal cross-sectional view of a main part, and FIG. 8 is a cross-sectional view taken along BB in FIG. 7. 5... Workbench, 6... Support legs, 7...
... Support leg insertion hole, 7A ... Support leg insertion hole wall, 8 ... Lifting mechanism, IOA, 10B ...
...Leg guide, 12...Fixing device, 13A,
13B...Plate material, 14A, 14B...
Welding, 15A, 15B... Teeth, 16...
・Insertion plate, 17 A, 17 B...Teeth, 18A
, 18B...Cover, 19...Bolt.

Claims (1)

[Scope of utility model registration request] Lifting type offshore work comprising a workbench and support legs that are supported by the workbench so that they can be raised and lowered relative to the workbench, and the supported state is obtained via a lifting mechanism interposed between the workbench and the support legs. A plate member provided with teeth projecting from the lower end of the support leg of the platform and the wall of the support leg insertion hole formed in the workbench and extending in the relative lifting direction on the tip edge; An elevating type offshore operation characterized by comprising an insertion plate that can be fitted and removed only in the thickness direction of the plate material between opposing teeth, and an insertion plate fall prevention cover that is attached between the pair of plate materials. Pedestal leg fixing device.