Abstract:
An apparatus according to the invention for suspending a submarine on a submerged structure and comprising a preshaped semi-rigid strap wound onto a drum disposed in a casing fixed to said submarine, whereby the strap when unwound adopts the shape of a generally circular loop so as to pass round one of the cross-members of the submerged structure and has at its free end means for cooperating with a locking device disposed on the path adopted by the strap with respect to the casing, whereby the locking device comprises safety means for bringing about the release thereof in the case of a defect to the locking system.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a suspension apparatus for immobilizing a submarine on a submerged structure. 
     The technical field of the invention is that of equipment used in the field of underwater operations. 
     The inspection and maintenance of oil drilling platforms at sea require the use of divers for the positioning of measuring pick-up. In general, the divers are brought to their working location by diving bells which have a very considerable vertical mobility, but no horizontal mobility. However, the inspection of platforms requires the divers to have access not only to the exterior of the supporting structure, but also to its interior. In view of the dimensions involved, such an access is impossible from diving bells. 
     Means for suspending submarines on a submerged structure are known. Such a known apparatus comprises a system of hook-like ramps which surround a cross-member of the structure, thus ensuring the maintaining in a fixed position relative to the platform structure of the submarine. 
     BRIEF SUMMARY OF THE INVENTION 
     The problem of the present invention is to provide a novel apparatus for attaching a submarine to a structure. 
     According to the invention, this problem is solved by an attachment apparatus, wherein it comprises a preshaped, semi-rigid strap which is wound onto a drum located in a casing fixed to the submarine, whereby when unwound, said strap adopts the shape of a generally circular loop so as to pass round a cross-member of said submerged structure and has at its free end means for cooperating with a locking device disposed on the route adopted by the strap with respect to the casing. 
     Thus, the invention provides an apparatus making it possible to suspend a submarine on one of the horizontal tubes of a submerged structure, whereby the diameter is of an arbitrary nature, but is generally between 400 and 2400 mm. 
     The advantages of such an apparatus are listed below: 
     the apparatus can be strapped to different sections of tubes; 
     the apparatus is retractable and has reduced overall dimensions in the retracted position, whilst being protected by protective ramps located in the upper part of the submarine; 
     the system has a low weight due to the use of very strong textile straps; 
     the safety and reliability of the system is ensured due to the existence of a jettisoning or release device on the locking funnel, whereby when it is not possible to unlock the strap, said release device makes it possible to completely release the locking funnel, thus permitting the strap to be wound into its casing. The funnel is released by means of pneumatic jacks. 
     It is stressed that said safety device operates on a circuit which differs from that supplying the other parts of the equipment, which are supplied by a hydraulic circuit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in greater detail hereinafter relative to non-limitative embodiments and with reference to the attached drawings, wherein show: 
     FIG. 1 a part elevation of a submerged structure illustrating two submarines in the attached position. 
     FIG. 2 a perspective view of a suspension system according to the invention. 
     FIG. 3 a sectional view of the apparatus of FIG. 2. 
     FIG. 4 an elevation of the casing in which is wound the suspension strap. 
     FIG. 5 a view from the left of the casing of FIG. 4 in part section illustrating the strap drive mechanism. 
     FIG. 6 a larger scale sectional view of the strap unwinding device. 
     FIG. 7 a cross-sectional view of the strap. 
     FIG. 8 an elevation of the strap locking funnel. 
     FIG. 9 a view from the left of the funnel of FIG. 8. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference is firstly made to FIG. 1 which shows a submerged structure 1, for example a platform moored at sea and which more particularly comprises oblique columns 1a and horizontal cross-members 1b interconnecting said columns 1a. In FIG. 1 a submarine 2 is shown in side plan and rear views, suspended on two cross-members 1b. 
     The suspension or attachment of the submarine on said structure is realised by means of an apparatus according to the invention illustrated in perspective in FIG. 2. This apparatus essentially comprises a casing 3 serving as a guide for the winding and unwinding of a strap 4 and a locking device 5. The apparatus is located essentially to the right of the fixing member for handling the submarine and therefore between two guidance ramps or guards 6 extending over the length of the submarine parallel to and on either side of its longitudinal axis. 
     When submarine 2 approaches structure 1, it is supported on the guards by sliding thereon until it arrives in the attachment position to the structure and this attachment operation will be described in greater detail hereinater. 
     Reference will now be made to FIGS. 2 to 7 which illustrate the various components of casing 3. The latter is in the general form of a cradle and has two side walls 3a interconnected by a curved and upwardly extending wall 3b, whilst on the opposite side to wall 3b there is a cross-member 3c. As shown in FIG. 3, the upper part of walls 3a is shaped in such a way that they partly surround a cross-member 1b of the structure to which attachment is to be effected. Thus, the profile of these walls is in accordance with a substantially horizontal line 3d extending from cross-member 3c over a portion of the casing length, an oblique line 3e approximately 120° from line 3d and finally line 3f forming an angle of 95° with line 3d. 
     Along lines 3d and 3e, the casing has abutment plates 3g/3h disposed transversely to walls 3a to which are fixed the PVC buffer plates 3j which dampen the engagement contact between structure 1 and submarine 2. 
     In its centre, casing 3 has a reel or drum 6&#39; rotating on a shaft 6&#39;a disposed transversely to casing 3 and perpendicularly to walls 3a. The shape of the lower part of casing 3 is such that at 3k its profile is substantially parallel to the peripheral contour of drum 6&#39;. The latter permits the winding and unwinding of strap 4 which, previously preshaped so that it winds onto itself, conforms to the curvature of wall 3b of the casing and retains its curvature after being drawn out of the latter in such a way that it passes round the cross-member 1b of the structure. Strap 4 is kept applied against wall 3b by means of rollers 3l disposed on an axis parallel to wall 3b. Casing 3 is mounted on a support 7 fixed to the submarine by its lower end 7a. 
     The strap is wound and unwound by means of a motor, for example a hydraulic motor 8, carried by support 7 and whose output shaft 8a is keyed to a coupling box 9, itself keyed to end 6&#39;b of shaft 6&#39;a. The other end 6&#39;c of said shaft is mounted in a bearing 7b of the support 7. 
     The coupling box 9 has a toothed wheel 10b which cooperates with a toothed belt 11, which winds round a toothed pinion 12 disposed on the side of the upper part of casing 3. This pinion 12 is keyed to the end of a shaft 13 which passes from one side of the casing to the other, whilst being parallel to wall 3b of said casing and mounted on two bearings 3m fixed to walls 3a. The casing has an opening 3n facing shaft 13 so as to permit the passage of a so-called pressing roller 14, which rotates freely on a shaft 14a parallel to shaft 13. This roller is mounted on two supports 14b fixed to said casing 3 and is pushed from the inside thereof by springs 14c, whose setting is obtained by means of screws 14d cooperating with tapped holes made in each of the supports 14b. 
     Shaft 13 carries the so-called driving rollers 13a keyed to said shaft 13 via a &#34;free wheel&#34; 15. The driving rollers 13a are located on either side of free wheel 15 in such a way that the driving device extends over the width of the casing (FIG. 6). As shown in FIG. 6, strap 4 is inserted between the pressing roller 14 and the driving rollers 13a. A tension roller 16 located on the route of one of the straps of the toothed belt 11 ensures the tensioning of the latter. 
     Strap 4 (FIG. 7) comprises two textile belts 4a connected to one another for example by stitching and inserting two preshaped spring blades 4b in such a way that the strap winds onto itself. One end 4c is fixed to drum 6&#39; and has at the other 4d a locking finger 17 having a generally cylindrical configuration, whose free end 17a is profiled, whilst its centre portion has a cylindrical constriction 17b. 
     Finger 17 cooperates with the locking device 5, located facing casing 3 in such a way that it surrounds cross-member 1b of the submerged structure. The locking device comprises a pyramidal funnel 5a ensuring the reception of finger 17, whilst the lower part of the funnel 5a is extended by a cylindrical passage 5b which receives finger 17 and acts as a notch. Funnel 5a and its passage 5b have a metallic structure 5f on which is mounted a double acting hydraulic jack 18, whose longitudinal axis extends transversely to passage 5b. At the end of its movable rod, this jack carries a locking fork arm 18a traversing said passage at 5c and which cooperates with the constriction 17b of finger 17. The fork arm has a profiled opening with two sections 18b and 18c in order to permit in a first retracted position the passage of the finger and in a second extended position its locking or vice versa. 
     The locking device 5 is carried by a support 19 having two parallel flanges 19a and of the same shape, spaced so as to permit the passage of structure 5c of device 5. The flanges are fixed to a tubular cross-member 6a which connects the guards 6. Columns 6b support both support 19 and guards 6. In the upper part of support 19 there are two channels which form slides 19b in flanges 19a. These slides face one another and are substantially vertical and of short length. Each of them receives a suspension arm 5d extending perpendicularly to the locking device 5 and to its lower part. Device 5 is secured by a double locking means. To this end, jacks 20 are fixed to the outside of the flanges 19a of support 19 in such a way that each of them is traversed by the movable rod of the jack which it supports. Thus, jacks 20 are in opposition on the same transverse axis to support 19 and are perpendicular to flanges 19a. Their movable rod constitutes a locking finger which penetrates an opening 5e in the metal structure 5c of device 5. These double acting jacks operate pneumatically and constitute a safety device. They serve to release or jettison the funnel 5 in the case where for some reason it is impossible to disengage strap 4 from locking device 5. It is clear that as a result of the operation of jacks 20 with their movable rods retracted, device 5 subject to a tensile force exerted by strap 4 is detached from support 19 and slides in slides 19b, thus freeing the submarine. The locking jack 18 has quick couplings which are themselves disengaged at the time of releasing device 5. 
     The locking device 5 is protected by guards 6 which run along the upper part of the submarine, as shown in FIG. 1. As can be seen in greater detail in FIG. 3, the device is located to the right of the counterbending 6c on guards 6. The special shape of the latter defines with casing 3 a recess in which is partly placed the cross-member 1 of the submerged structure. 
     Casing 3 is mounted so as to pivot around the axis 6&#39;a of drum 6&#39; in such a way that it can be retracted towards the right of FIG. 3, so that the curved wall 3b can approach the bridge of the submarine. The casing is in this position when the submarine is not attached to the structure. The rocking of the casing is obtained by means of a double acting hydraulic jack 21, articulated on the one hand at 21a to a structural element of the submarine and on the other at 21b to the lever 3p connected to casing 3. 
     With casing 3 in the working position, i.e. with wall 3a raised, it initially serves as a positioning abutment for the submarine relative to cross-member 1b and then serves as a guide for strap 4 during the winding or unwinding thereof. The strap is stored around drum 6&#39;  which is directly rotated by hydraulic motor 8. The transmission by toothed belt and pinions 10b, 12, 11, under the action of motor 8 drives the driving rollers 13a with a view to obtaining the unwinding of the strap by tension. 
     When the strap has passed round cross-member 1b, it firstly penetrates funnel 5a and is then locked by the locking device 18 to the right of constriction 17a of finger 17. 
     Strap 4 is wound up by motor 8 only, the latter being rotated in the reverse direction of that for unwinding. This is possible due to the fact that the driving rollers 13a are mounted on free wheel 15 which functions in the winding direction of strap 4. 
     The attachment takes place in the following manner: the submarine 2 makes its initial approach to cross-member 1b; the operator rocks the casing 3 so as to bring it into the operational position; the operation being continued by permitting the submarine to slide on guard 6 whilst maintaining contact with the cross-member 1 until it is immobilised against casing 3. 
     Once equilibrium has been obtained, the strapping of the cross-member 1 is brought about by strap 4 and the latter is locked in device 5. Finally, the assembly is completely secured to rotating hydraulic motor 8 in the opposite direction. 
     When the maintenance or inspection is completed, the above operations are performed in the reverse order to free the submarine. 
     The invention is not limited to the embodiments described and represented hereinbefore and various modifications can be made thereto without passing beyond the scope of the invention.