US3420318A - Apparatus for the handling and assembling of tubular rigid elements on a floating installation - Google Patents

Description

7, 1969 J. DELACOUR ET'AL 3,420,318

APPARATUS FOR THE HANDLING AND ASSEMBLING OF TUBULAR RIGID ELEMENTS ON A FLOATINGX INSTALLATION v Filed March 28. 1966 Sheet of 4 J. DELACOUR ETAL 3,420,318

BULAR APPARATUS FOR THE HANDLING AND ASSEMBLING OF TU RIGID ELEMENTS ON A FLOATING INSTALLATION Sheet 2 of 4 Filed March 28, 1966 LAR 1969 .1. DELACOUR ETAL APPARATUS FOR THE HANDLING AND ASSEMBLING 0F RIGID ELEMENTS ON A FLOATING Filed March 28, 1966 TUBU INSTALLATION heet s 3 of 4 7, 1969 J. DELACOUR ETAL- 3,420,313

APPARATUS FOR THE HANDLING AND ASSEMBLING 0F TUBULAR RIGID ELEMENTS ON A FLOATING INSTALLATION Filed March 28, 1966 Sheet 4 of 4 6| I AX '65 Ad I A 3 Ad Ad United States Patent us. Cl. 175-5 rm. Cl. EZlc 19/00 9 Claims ABSTRACT OF THE DISCLOSURE A floating apparatus for assembling rigid elements has a platform provided with a passage for the column formed by the rigid elements and has means for supporting this column. The platform is supported on the floating installation by a Cardan type joint having two rectangular axes. An elongated frame is rotatably mounted on the platform around an axis having the same direction as one of the axes of the platform and is movable from an upper position substantially in alignment with the passage in the platform to a lower position substantially in alignment with the other axis of the platform. The elongated frame is provided with means for gripping the rigid elements in its lower position.

The present invention relates to apparatus for the handling, assembling and disassembling on a floating installation of elongated rigid elements to be connected end to end forming a column which is submerged from the floating installation.

These elements can be, for example, rigid elements forming a drill string for underwater boring from a floating installation such as, for example, a drilling vessel and this specific example of the present concept will be referred to hereinafter in describing the present invention without, however, limiting the scope thereof.

During a boring operation of this type, the rolling and pitching movements to which the floating installation is subjected make the steps of handling, assembling and disassembling the rigid elements of the drill string difiicult these elements including drill rods, drill collars and optionally a bottom motor.

The operations of assembling and disassembling of the rigid elements of the column can be more easily carried out if a platform is provided on the floating installation which is not subject to the movements of the installation and which provides a passage through which the rigid elements secured end to end and forming the column are passed. The column passes through the platform and extends beneath the floating installation.

A servo-mechanism can be provided to maintain a fixed orientation such as horizontal of this platform in spite of the movements of the floating installation. In this way the assembling or disassembling of the elements can be carried out easily on the platform. Moreover, the column is no longer subjected to large stress variations at the point where the column passes through the platform, stress which would result from forces exerted on the immersed part of the column in the case of a platform solidly connected to the floating installation.

A problem however arises in the handling of the rigid elements between a storage area of these elements located on the floating installation and the platform which does not undrgo the movements of the floating installation.

The system of the present invention provides the best conditions for the different operations of handling, assembling and disassembling independently from the movements of rolling and pitching of the floating installation from which the subsurface drilling is carried out.

This apparatus includes a platform or oscillating table which is freed from the rolling and pitching movements of the floating installation by a mounting on a Cardan joint type support permitting rotation of the table or platform about two rectangular axes.

This platform has an opening for the passage of the rigid elements and includes in the vicinity of the opening means for supporting the rigid elements in the opening during assembling with other rigid elements.

In combination with the table, the present invention includes a system for handling rigid elements which is a combination of apparatus for the transfer of these elements from a storage area on the floating installation to a position in alignment with a first of the two axes of the table and apparatus for lifting the rigid elements, said apparatus having a longitudinal axis situated in a plane perpendicular to the second axis of the table and passing through the first axis with means for rotating the lifting apparatus about its axis of articulation passing from a low position where its longitudinal axis is aligned with the first axis of the table to an upper position where its longitudinal axis is substantially aligned with the axis of the opening in the table, the apparatus for lifting the elements including means for gripping and guiding the rigid elements while maintaining them in a position parallel to the longitudinal axis of the lifting apparatus.

The invention will be described hereinafter in detail referring to the accompanying drawings, which illustrate a preferred embodiment thereof, and in which like reference characters indicate like parts. In the accompanying drawings,

FIG. 1 is a view from above of a drilling vessel or ship equipped with an embodiment of the present invention with the apparatus for lifting the rigid elements in lowered position in contact with the transfer apparatus for gripping one of the elements;

FIG. la is a side view of the vessel of FIG. 1 in partial longitudinal section with the lifting apparatus in lowered position;

FIG. 2 is a view of the vessel similar to that of FIG. la with the lifting apparatus for the rigid element holding a rigid element in a position substantially perpendicular to the table;

FIG. 3 is a partial view on a larger scale of the embodiment of FIG. 1;

FIG. 4 is an enlarged detail of the structure for supporting the rigid elements in the openings of the table;

FIG. 5 is a schematic view of means for controlling the orientation of the table.

In the embodiment shown in the drawings, the present apparatus is installed on a vessel 1 which is equipped for boring operations under the surface of the water by means of a flexible conduit on which is suspended a boring tool driven by a motor which is not shown.

In this type of drilling, the rigid elements of the drilling column comprise the drilling tool, the bottom motor which rotates the tool and optionally drill collars thereabove. It should be understood, however, that this illustrative embodiment of the present invention showing a particular method of drilling can be used with other drilling processes as, for example, the conventional process where the drilling column is formed entirely by the joining of rigid elements.

The present invention, as already mentioned, can have other uses than under water drilling and could be used whenever there is need to manipulate and assemble elongated rigid elements end to end from a floating installation.

The drilling column passes through opening 3 in the vessel. The rigid elements R are assembled one to the other and fastened to the end of flexible conduit 2 which passes over pulley 4 carried by slide 5 mounted on track 7 which is fixed to frame 8. Slide 5 is supported by the piston of a jack 16 articulated at 17 on the base of frame 8. Jack 6 maintains the tension on flexible conduit 2 substantially constant despite any vertical movement of the vessel during the drilling operation utilizing the flexible conduit as the drilling conduit.

Conduit 2 then passes on pulley 9 and then through a traction or drawing device 10 comprising two endless chains C and C (FIG. 1) carrying grippers which surround conduit 2 and move it either during rolling up on the storage drum 11 which is driven by motor 12 or while unrolling the conduit from this drum.

Pulley 13 and rollers 14 guide flexible conduit 2 between traction device 10 and drum 11.

Feed of drilling fluid to the bottom drilling tool and electrical connections between the bottom and the surface are provided through flexible conduit 2 which is connected on the vessel to feed devices through axis 15 of the drum 11 to which one end of the flexible conduit is connected.

In accordance with the present invention a platform or oscillating table is mounted above opening 3 which is provided through the bottom of the vessel.

This table comprises, in this embodiment, an upper deck 18 and a lower deck 19.

The two decks are provided with openings 30 and 31 respectively, for the passage of the drilling column.

This table is supported on a Cardan type joint carried by base 20 mounted on the deck of the vessel.

This type of joint provides tWo axes of rotation for the table which are perpendicular and are shown at X'X and YY and includes a fork 21 integral with a shaft in alignment with axis YY.

Axis Y'Y in this embodiment is situated in the longitudinal plate of symmetry of the vessel and is parallel to the rolling axis of the vessel, but this is not critical and any other suitable orientation can be used.

The oscillating table is articulated in fork 21 on an axis X'X which, in this particular embodiment, is perpendicular to the axis Y'Y and therefore substantially parallel to the axis of pitch of the vessel or reasonably close thereto.

Because of this Cardan type joint, the oscillating table can be freed from the rolling and pitching movements of the vessel and can be given a desired orientation with respect to reference planes fixed or not with respect to the vessel during assembling and disassembling operations of the rigid elements of the drilling column.

The oscillating table has the following principal modes of operation:

(1) The table is maintained with a fixed orientation with respect to the vessel which orientation is represented, for example, by the angles that the table makes with two planes of reference associated with the vessel and passing through the axes X'X and Y'Y. The values of these angles can be fixed by blocking rotation of the table about axes X'X and Y'Y, and optionally regulated, for instance periodically, by turning the table about these axes, for example by means of two jacks 32 and 34 (FIG. 3).

The angles of inclination chosen for the table should be those providing an acceptable value for the forces acting on the column of rigid elements already assembled and extending beneath the table as they pass through openings and 31 and a convenient value for the forces on the table at points 30 and 31 of the assembly.

With particular reference to FIG. 3, jack 32 has its cylinder articulated at 33 on fork 21 on an axis parallel to X'X and acts on the upper deck 18 of the oscillating table to control its rotation about the axis X'X.

Jack 34 has its cylinder articulated at 35 on the deck of the vessel about an axis parallel to the axis Y'Y and rotates the oscillating table about the axis YY.

It should be understood that the means used to rotate the oscillating table about the axis X'X and Y'Y can be other than jacks and any appropriate means can be utilized such as two motors, one of which is disposed on the deck of the floating installation 1 to rotate fork 21 about its axis Y'Y through a gear train with another motor mounted on fork 21 to rotate the oscillating table about its axis XX through another train of gears.

The first mode of operation, where the angles of the oscillating table with two planes of reference associated with the vessel are maintained constant, is applicable only when the movements of the vessel in roll and pitch have a small amplitude and slow speed.

When the amplitude and speed of the roll and pitch of the vessel and the length of the column submerged under the vessel pass certain values, the submerged portion of the rigid column which is moved with the roll and pitch of the vessel is subjected to forces of hydrodynamic resistance which can deform it or break the part under the table with damage to the table adjacent points 30 and 31 of the assembly.

In this situation other modes of operation should be employed.

(2) When the portion of the column under the table has a sufficient length and weight, the table can be permitted to oscillate freely about its two axes of rotation X'X and Y'Y, the system formed by the column and oscill ating table having a natural stability which is suflieient to maintain the table in a substantially horizontal orientation with the column of rigid elements maintaining a direction very close to the vertical in spite of the rolling and pitching movements of the vessel.

Free oscillation of the table is obtained by discontinuing the action of jacks 32 and 34 which can be done simply by establishing communication between the spaces in the cylinders on either side of the piston.

Under conditions of free oscillation of the table, the part of the column which is under the oscillating table and is formed by the assembly of the rigid elements is not substantially subjected to bending forces and the openings 30 and 31 in the decks of the table are not to be subjected to breaking stresses contrarily to what occured in the preceding mode of operation.

(3) The third method of operation is used when the value of certain parameters, such as the period of roll and period of pitch of the vessel, the period of oscillation of the system constituted by the assembly of rigid elements already connected and the oscillating table lead to undesirable movements of the oscillating table if it is permitted to oscillate freely around its two axes of rotation in spite of a good stability of this system in the absence of movements of the vessel.

To overcome these inconveniences, the oscillating table is continuously controlled by means rotating it about its axes X'X and Y'Y, such as jack means 32 and 34, to maintain the direction tt, which is perpendicular to the table, in the direction D in space for which the forces acting on the part of the assembly of rigid elements located under the oscillating table and on the points 30 and 31 are minimum.

In one practical way of obtaining this control through control of jacks 32 and 34 which bear on the vessel and are subject to the rolling and pitching movements, the angles on and [3 between the direction tt perpendicular to the oscillating table and two reference planes passing for example through the axis of rotation of the table X'X and Y'Y respectively are determined and jacks 32 and 34 are actuated in such a way as to make these angles at any given instant equal respectively to the angles a and ,8 of the direction D with the same reference planes, respectively.

Coincidence of the perpendicular t't to the oscillating table and the chosen direction in space is therefore assured.

This can be automatically done by a control system in which the angles a, B, on and B are transformed in known manner to proportionate electric voltages and where electric voltages proportionate to the difference otoc' and ,8-[3' respectively are provided by differential amplifiers and then used to control electrically actuated valves controlling the quantity of fluid, such as oil, delivered to jacks 32 and 34 from a reservoir through a pump providing appropriate oil pressure.

The direction D in space with which the perpendicular ft is to coincide can either be fixed in space, vertical for example, or be the direction of guide means for the submerged part of the drill column such as guide cables extending between the bottom of the sea and the vessel.

(a) When the direction D is fixed in space, it will be defined by the angle that it makes with the vertical (which can be determined by the equilibrium of a liquid level or by a pendulum or by gyroscopic means) and by the angle made by a vertical plane parallel to this direction D with a fixed horizontal direction such as north as furnished by a magnetic compass of known type or by gyroscopic means which may or may not be different from the first gyroscopic means.

(b) The other case is that where the assembly of rigid elements is guided during submersion as by a system of two guide cables maintained under tension between the vessel and a structure resting on the bottom around the opening of the bore hole.

The guide cables 52 and 53 (FIG. 1a) pass through the upper and lower decks of the oscillating table through openings 54, 55 and 56, 57 respectively. They are placed under tension by known means as by winches which can be placed for example on the oscillating table or carried by frame 8.

In this guide system, the column formed by the assembly of rigid elements is maintained during its submersion at a substantially constant distance from each of the guide cables and in the plane of the cables by guide devices of known types sliding along the cables.

These guide devices could be stored on the lower deck 19 of the oscillating table. To facilitate their passage through this deck, the deck can be made up of two separable sliding members each of which being provided with a part of the opening 31, as can be seen in FIG. 3.

Because of the mechanical connection between the guide cable and the rigid elements, the assembly of elements is subjected not only to the action of its own weight and to the forces of marine currents but also to the forces acting towards the guide cables.

It is understood that the guide cables extending between the vessel and the head of the bore hole have at any given moment an obliquity which can be large by reason of the movement of the vessel froma position in vertical alignment with the bore hole.

Under these conditions, it is the direction of the tangent to the curve of equilibrium of the guide calbles immediately under the oscillating table which is the reference direction D on which the perpendicular t! to the oscillating table will be continuously oriented by controls of the type discussed above.

The orientation of the guide cables can be determined with an inclinometer of known type utilizing one of the cable guides or, independently of the latter, by the taut wire of an inclinometer extended between the head of the bore and the vessel.

The inclinometer measures as electric signals the angles of inclination on two rectangular reference planes made by the direction of the guide cables in proximity to and immediately beneath the oscillating table.

Under conditions where the angle of pitch of the vessel is small while the angle of roll is large, the method of operation discussed above in paragraph 3(a) or (b) can be simplified. Under these circumstances, the table can oscillate freely about the axis of pitch X'X or one can fix the angle formed between the plane of the table and a plane associated 'with the vessel passing through this axis,

with optionally periodic adjustment of this angle. Under these conditions, only the movements of the table due to roll (rotation about the axis YY) are to be determined and the determined angle of roll is used to control the table as in the methods of operation discussed above in paragraphs 3(a) or (b). This maintains the perpendicular t! to the table in a given orientation despite the movements of roll of the vessel which orientation may be fixed in space, determined with respect to the vertical or oriented in accordance with the direction of the guide cables.

The control system of the oscillating table, as shown schematically in FIG. 5, includes an inclinometer 58 of known type detecting in the form of electric signals a, and 5, respectively, the angles of the direction of guide cables 52, 53 under the lower deck of the oscillating table with the vertical planes passing through axis X'X and Y'Y of this table, respectively.

Inclinometer 58 could be mounted on lower deck 19 of the table and associated with either of the cables 52 or 53, FIG. la.

It is also possible to use two potentiometers of the type used in inclinometers associated with each of the two cables under deck 19 of the table, each measuring as electric signals the inclination of the cable to the vertical plane passing through the axis X'X (signal a) and the inclination of the other cable to the vertical plane passing through Y'Y (signal ,8).

Further potentiometers which can be of a known type as shown at 59 and 60 respectively in FIGS. 3 and 5 determine as electric signals the angles and of rotation of the oscillating table around its axes X'X and Y'Y, respectively, that is the angles between the perpendicular ft to the table and the vertical planes passing through X'X and Y'Y respectively. These signals are transmitted by electric conductors 61 and 62 respectively (FIGS. 3 and 5) to known types of differential amplifiers Ad and Ad respectively, furnishing signals A04 and AB, proportional to the difference between on and a and the difference between B and ,8 respectively. These signals Act and A5 are compared in other differential amplifier Ad and Ad,, with preselected ditferences Aoc and A 8 respectively, as settled by potentiometers 63 and 64.

These preselected differences characterize the desired orientation to give to the perpendicular t't of the oscillating table with respect to the reference direction D provided by the guide cables and these preselected differences will be zero if it is desired to orient t't in the reference direction.

The differential electric signals AX and AY provided respectively by Ad and Ad.; are utilized as control signals for electrically actuated valves 65 and 66 in the hydraulic feed circuits of jacks 32 and 34, respectively, to control the volume of hydraulic fluid admitted to each of these jacks. The hydraulic feed circuits of the valves as well as the hydraulic feed circuits of the jacks 23 and 24 have not been shown and are within the skill of the art.

Means which are provided on the oscillating table to hold the rigid elements in the openings 30 and 31 of the decks of the table can be of known type.

One particular way of retaining the rigid elements in the opening 30 is illustrated in FIG. 4 as a schematic view partially in section in a plane passing through the axis tt of opening 30 perpendicular to the table. Opening 30 is provided in a circular plate 36 which can rotate about the axis 1'! on circular bearing 37 fixed to upper deck 18 of the table by pins such as 38 and 39.

The diameter of opening 30 in plate 36 is larger than that of the drill column so that the drill column will pass through it.

Rigid elements R include sections of reduced thickness such as flats 40 and 41 having shoulders 42 perpendicular to the axis tt.

The rigid elements can thus be retained in rotary plate 36 by wedges 43 inserted between the wall of opening 30 and rigid element R at a flat 40, the shoulder 42 of the element R then abutting against wedge 43.

Wedges 43 lock element R solidly in plate 36 and element R can be rotated by rotation of plate 36 by means analogous to those utilized in the known techniques of rotary drilling.

In this way rigid element R which is fixed in rotary plate 36 can be screwed to the extremity of another rigid element brought above opening 30 of the table in a position perpendicular thereto by the handling system which will now be described.

In combination with the oscillating table there is provided, in accordance with the present invention, a system of handling for the rigid elements of the drill column bringing these elements from a storage position situated on the floating installation into a position approximately perpendicular to the plane of the oscillating table which can be free from the rolling and pitching movement of the vessel for introduction of the rigid elements into the opening- s 30 and 31 in the table and for connecting the rigid elements together.

The structure also provides for the reverse operation of disconnection of the rigid elements when the drill column is raised and the transfer of the disconnected elements to their storage position on the vessel.

The system for handling the rigid elements includes lifting apparatus 22 for the elements combined with a transfer system 26 for the elements.

The lifting device 22 includes an elongated frame 44 extending along an axis ZZ situated in the plane passing through the first axis of rotation Y'Y of the oscillating table perpendicular to its second axis XX.

The lifting device is articulated around an axis coincident with the axis XX and is carried by fork 21.

A lifting slide 45 slides along frame 44 and carries two half collars M and M which can be closed by rotation around an axis parallel to ZZ, to grip the flats 40 and 41 of a rigid element R (FIG. 3).

The displacement of slide 45 along frame 44 is provided by a cable 46 passing over pulley 47 at the extremity of frame 44. Cable 46 is wound on winch 48 which is mounted on an axis carried by frame 44 perpendicular to the axis ZZ. Rotation of winch 48 is controlled by electric motor 48a.

Frame 44 includes at a short distance from winch 48 two half collars N and N which can be closed around rigid element R without gripping it.

Half collars M, M and N, N when close, form circular sleeves having axes coinciding with the axis ZZ of frame 44.

Rotation of the lifting device 22 about its axis XX is provided by jacks 23 and 24 whose cylinders are articulated on the oscillating table on an axis parallel to XX- The articulation 25 of cylinder 24 is seen in FIGS. 1a and 2.

The transfer device for the rigid element R combined with the lifting device 22 provide transfer of the rigid elements from a storage area 28 where they are for example disposed perpendicularly to the axis of rotation XX of the lifting device 22, with the transfer taking place along a direction parallel to this axis in the illustrated embodiment.

The transfer device includes in the embodiment shown by way of example a support member 26 which can be displaced parallel to the axis XX on track 27 comprising rails or rollers.

In certain cases, the rigid element R can be stored on support member 26 itself if its storage capacity is sufiicient.

Handling of the rigid elements R takes place as follows:

A cylindrical rigid element R is moved by the transfer system 26 to a position where its axis is in alignment with the longitudinal axis Y'Y. The lifting device is then lowered toward the support member 26 of rotation around its axis XX by actuating jacks 23 and 24 until the axis ZZ of collars N, N and M, M, which are carried by frame 44 and are in open position, comes into coincidence with the axis Y'Y with which the axis of rigid elemnt R is already in coincidence.

The collars M, M and N, N can then be closed on element R.

The systems 22, 26 in accordance with the invention for handling rigid elements R provides for the gripping of the element on support member 26 when it is in the position described above and seen in FIGS. 1, 1a and 3, without the element being subjected to any stress or damaged irrespective of the relative movements of pitch and roll of the oscillating table with respect to the ship and in particular with respect to the storage area.

The movements of pitch of the ship with respect to the table can occur freely in spite of the mechanical connection between the oscillating table and frame 44, as consttiuted by the jacks 23 and 24 which rotate element 44 about axis XX. It is sufficient therefor to establish a communication between the cylinder parts on both sides of the piston of each jack 23 and 24 and the oil reservoir feeding these jacks as soon as element 44 of the lifting device 22 comes in contact with support member 26. Device 22 then rests on member 26 by its own weight.

Further, the rolling movements of the oscillating table can be free in this position of device 22.

When the collars M, M anud N, N grip a rigid element R resting on support member 26, or during the reverse operation, the axis of the cylinder of the rigid element R is in coincidence with the axis of collars M, M and N, N and with the axis of roll Y'Y of the oscillating table. The assembly of the elongated frame 44 and collars M, M and N, N which is connected to the table through its axis XX can then undergo movements of rotation around Y'Y due to roll without any force or displacement being transmitted to the rigid element R which remains under its own weight on the support member 26.

To lift element R gripped between the collars M, M and N, N, the communication previously established between the cylinder parts on both sides of pistons of jacks 23 and 24 is interrupted and oil under pressure is provided to these jacks.

Device 22 is thus raised under the action of jacks 23 and 24 to occupy a position in which its axis ZZ is substantially coincident with the axis tt of opening 30 of the oscillating table and perpendicular to said table (FIG. 2).

The raised rigid element R is thus located substantially in alignment with openings 30 and 31 of the oscillating table.

In the illustrated embodiment, frame 8 should be slightly moved by rotation around an axis 29 parallel to axis XX to permit device 22 to reach said position perpendicular to the table (FIG. 2). Rotation of frame 8 is provided by jack 50 articulated at 51.

Axes of rotation 29 and 33 are carried by a structure 49 supporting frame 8 and secured to the deck of the vessel.

When rigid element R has been placed above the oscillating table in alignment with the axis l't, its connection to the other rigid elements, already introduced in the openings 30 and 31 of the table and to the extremity 6 of the flexible conduit 2, can be easily attained since the oscillating table can be freed from the rolling and pitching movements of the vessel.

Displacement of slide 45 along frame 44 permits movements of ascent and descent of rigid element R carried by collars M, M and guided by collars N, N during the connecting and disconnecting operations for the element.

During these movements of the slide the axis of rigid element R remains coincident with the axis ZZ and with the axis tt of orifice 30 perpendicular to the upper deck of the table.

During the descent of slide 45 under the action of Winch 48 along element 44 to introduce element R into orifice 30 or to connect it to another rigid element R 9 already mounted in this orifice, where it is supported by Wedges 43 (FIG. 4), it is advantageous for the half collars N, N to open to permit slide 45 and rings M, M to pass without altering the alignment of element R with the axis Z'Z of the lifting device and the axis t't of orifice 30.

Connection of an element R carried by slide 45 to another element R mounted in orifice 30, as illustrated in FIG. 4, can be obtained by screwing the two elements together by rotating plate 36, as described above with reference to the known technique in the rotary drilling art.

The column of assembled rigid elements is then gripped by collars M, M, lifted to permit removal of wedges 43 and then lowered by displacement of collars M, M, along frame 44. Wedges 43 are then put in place to retain the column of elements by the upper end of the last assembled element R of the column.

The disassembly of the rigid elements of the column is carried out by the reverse process to that of the assembly operation described above.

Changes in or modifications to the above-described illustrative embodiments of the present invention may now be suggested to those skilled in the art without departing from the present inventive concept. Reference should therefore be had to the appended claims to determine the scope of this invention.

What is claimed is:

1. Apparatus for the handling, assembling and disassembling on a floating installation of elongated rigid elements to be connected end to end to form a rigid column to be submerged from the installation, comprising a storage location for said elongated rigid elements, on the floating installation, a platform, a Cardan type joint between said platform and the floating installation for rotation of said platform about two axes disposed at right angles, an opening in said platform forming a passage to the water for said rigid column, means for supporting said rigid column substantially perpendicularly to said platform, a handling system for said rigid elements associated with said platform, transfer device for said rigid elements from said storage location to a position in alignment with one of the two axes of said platform, a lifting device for said rigid elements mounted for rotation around an axis having the same direction as the second one of said two axes of the platform, an elongated frame for said lifting device having its longitudinal axis located in a plane passing through the first axis of said platform and perpendicular to said second axis of said platform, means for rotating said lifting device between an upper position in which said frame is substantially in alignment with said opening in said platform and a lower position in which the longitudinal axis of said frame is in alignment with the first axis of said platform and means for holding and gripping said rigid elements on said frame.

2. Apparatus as described in claim 1, the floating installation having a rolling axis and a pitching axis, the first axis of rotation of said platform being parallel to the rolling axis of the installation, said transfer device moving said rigid elements between said storage location to a position in alignment with said first axis of rotation of said platform.

3. Apparatus as described in claim 1, for underwater drilling by a drilling tool driven by a bottom motor mounted at the lower end of the column of said rigid elements, a.flexible conduit connected to the upper end of the column, a structure mounted on the floating installation, a pulley at the upper end of said structure over which said flexible conduit passes, means for pivoting said structure about an axis parallel to said second axis of said platform between a first position in which said pulley of said structure is above said platform and a second position removed from said platform whereby said lifting device can be raised to its upper position on said platform.

4. Apparatus as described in claim 1, said means for gripping said rigid elements comprising collars and means for displacing said collars longitudinally along said frame of said lifting device.

5. Apparatus as described in claim 4 including a winch and cable means for displacing said collars, a pulley mounted on said frame of said lifting device, said cable means passing over said pulley and being wound on said winch.

6. Apparatus as described in claim 1, said Cardan type joint comprising a fork having two spaced arms each provided with bearings, said fork being pivotably mounted for rotation about its axis of symmetry coincident with the first axis of rotation of said platform, further bearings for said fork carried by the floating installation, said platform being mounted on the bearings of said arms of said fork disposed along the second axis of said platform and means for rotating said platform about each of said axes.

7. Apparatus as described in claim 6, said means for rotating said platform comprising a first jack means mounted on the floating installation and connected to an arm of said fork and second jack means mounted on said fork and connected to said platform.

8. Apparatus as described in claim 6, comprising means for maintaining said platform in a position fixed with respect to a reference direction independent of the floating installation including detection means for the orientation of said platform given by the inclination with respect to two planes of reference of a perpendicular to said platform, means for measuring the respective inclinations of the reference direction to said planes of reference, means for measuring the actual differences between said respective inclinations of the perpendicular to said table and of the direction of reference with respect to the two reference planes, means for setting preselected values for said respective differences, means for measuring as electric signals the deviations between said actual differences and the corresponding preselected values, and means for rotating said platform responsive to said electric signals.

9. Apparatus as described in claim 8, including cables extending between the floating installation and the bottom, guiding said rigid elements during their submersion from the floating installation, wherein the direction taken by said cables constitutes said reference direction.

References Cited UNITED STATES PATENTS 2,606,003 8/1952 McNeill 85 X 3,010,214 11/1961 Postlewaite 166-.5 X 3,276,746 10/1966 Berne 175-7 3,294,185 12/1966 ONeill et al. 175-85 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner.

US. Cl. X.R. 175-85

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