JPS5920423Y2 - 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. The present invention relates to a leg fixing device for a lifting-type offshore work platform (rig) that is 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. 2 towers over the workbench 1, placing a heavy burden on the elevating mechanism 3 that supports it.

That is, as shown in FIG. 2, when the workbench 1 is shaken by waves etc. in the state shown in FIG. Specifically, a large bending moment) M (first Diagram a
, b) occurs.

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 P 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
Since the pinion 3A supports the weight of 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 M generated on the pinion 3A.

Further, although the support leg 2 is made up of a plurality of tubular cords, the cords themselves may not have sufficient strength due to the bending moment l-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 thereon.

The elevating mechanism 8 includes hooks (
(not shown), and by rotating these pinions 8A in the forward or reverse direction, the support leg 6 can be moved through the insertion hole 7 relative to the workbench 5. It can be raised and lowered.

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 10A 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.

The structures shown in FIGS. 7 to 9 are designed in consideration of not only strength but also ease of attachment and detachment, functionality for raising and lowering the support legs 6, and reusability.

That is, the thick plate materials 13A and 1
3B are fixed and protruded by vertical welding 14A and 14B, and a wedge mechanism 15 connects the root rods 13A and 13B.

The wedge mechanism 15 includes a plurality of (two in the illustrated example) inclined surfaces 16A provided at the tip edge of each plate material 13A, 13B;
16A', 16B, 16B', and corresponding inclined surfaces 16A and 16B.

It consists of two sets 17° 17' consisting of a pair of wedge plates 17 A, 17 B, 17 A', 17 B' inserted between 16 A' and 16 B'.

These wedge plate sets 17, 17' have mutually opposite wedge faces 17C, 17C'.

The plurality of inclined surfaces 16A, 16A', 16B, and 16'B' are set along the above-mentioned relative lifting direction Surfaces 16A and 16B, 16A' and 1
6B' are configured to be substantially parallel (including parallel).

Covers 18 A and 18 are provided on both sides of the wedge plate assembly 17 and 17' to prevent the wedge plate assembly 17 and 17' from falling out of plane.
B, 18 A', and 18 B' are arranged and fixed to the plate materials 13A and 13B via bolts 19.

Elongated holes 20 and 20' are formed in the covers 18 A, 18 B, 18 A', and 18 B', respectively, and the covers 18 A, 18 B, and 18 are inserted through these elongated holes 20 and 20'.
A'.

The wedge plates 17B and 17A' are prevented from falling off by the pins 21 and 21' held in the wedge plate 18B' in a loosely fitted state.

In this case, the plates 13A, 13B and the wedge mechanism 15 act as strength members, and the covers 18A, 18B, 18A'
, 18 B', bolts 19, 21.21' do not act as strength members.

According to the above, through the action of the upper and lower wedge plate sets 17 and 17' that constitute the wedge mechanism 15, a situation in which the work platform '5 and the supporting legs 6 are displaced in the relative upward and downward direction is reliably prevented. Ru.

In the illustrated example, only one pair of upper and lower sloped surfaces are provided at the leading edge of the plate material, but the sloped surface may be formed of two or more.

In that case, it is necessary to use multiple sets of wedge plates.

The wedge plate sets 17 and 17' are used to attach the corresponding inclined surfaces 1 of each of the plates 13A and 13B after the elevating type offshore work platform has been transported by sea.
6A, 16B, 16A', and 16B', and the connection between the workbench 5 and the support legs 6 is released to allow relative movement up and down.

When removing wedge plate assembly 17.17', remove bolt 2.
1.21', cover 18A, 18B, 18 A', 18
Of course, B' can be 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.

In particular, since the work platform and support legs are connected by a wedge mechanism, not only will the connection not come loose during sea transportation, but the connection between the two can be easily released, and in that case, it is possible to prevent fires such as gas cutting. Since there is no need to use any of the above, there is no risk of damaging surrounding members.

[Brief explanation of the drawing]

Figures 1a, b and 2 are explanatory diagrams of conventional examples, and Figures 3 to 9
The figures show an embodiment of the present invention, FIG. 3a. b is an explanatory drawing, FIG. 4 is a plan view, FIG. 5 is a schematic sectional view, FIG. 6 is a cross-sectional view taken along line A-A in FIG. 5, FIG. 7 is a vertical sectional view of the main part, and FIG. is a cross-sectional view taken along line B-B in Fig. 7, and No. 9
The figure is a cross-sectional view. 5... Workbench, 6... Support legs, 6A.
... Tubular cord, 7 ... Support leg insertion hole,
7A... Support leg insertion hole wall, 8... Lifting mechanism, IOA, IOB... Leg guide, 12.
...Fixing device, 13A, 13B...Plate material, 14A, 14B...Welding, 15...
Wedge mechanism, 16 A, 16 B, 16 A'. 16B'... Slanted surface, 17.17...
Wedge board set, 17A, 17B, 17 A', 17 B'
...Wedge board.

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 material is protruded from the lower end of the support leg on the platform and a wall of the support leg insertion hole formed in the workbench in a state of facing each other, and a tip edge of each plate material is provided along the relative lifting direction and inclined. In addition to having a plurality of inclined surfaces whose directions are alternately opposite, the corresponding inclined surfaces between each plate material are made substantially parallel to each other, and a plurality of sets of wedge plates are inserted and extracted between the corresponding inclined surfaces. A leg fixing device for an elevating offshore work platform, characterized in that it is equipped with an assembly.