MXPA99008027A - Jack-up platform locking apparatus - Google Patents

Abstract

A locking mechanism (28) is disclosed for use on the legs (14) of a jack-up offshore platform (10). Each chord (18) of the legs (14) includes a rack (22) cooperating with pinions (26) used in raising and lowering the legs. The locking mechanism (28) includesa rigid frame attached to the hull (12) of the platform (10) and housing (36) and a plurality of vertically aligned toothed chock segments (30, 32, 38) to engage the teeth (24) of the rack (22) on a leg (14). The chock segments have upper and lower inclined surfaces cooperating with upper and lower movable wedges (48, 52) for supporting the chock segments (30, 32, 38). Subsequent engagement and retention of the supporting wedges (48, 52) securely locks the chock segments (30, 32, 38) into mating engagement with the rack teeth (24), to thereby lock the platform legs (14) in place.

Description

"LIFTED PLATFORM LOCKING DEVICE WITH CATS" BACKGROUND OF THE INVENTION This invention relates to the field of interlocking and leg support systems for self-elevating platforms or towers raised with jacks of the type used in the offshore exploration and production of hydrocarbons, as well as for other purposes. Offshore platforms have been used extensively through the oil and gas industry in continental shelving regions for oil and gas drilling, production, operations, pipe line pumping stations, personnel accommodation and various services and operations. reconditioning. Off-shore fixed platforms, intended to remain in one place, are traditionally constructed on the coast, transported by a barge to the offshore location, launched and rotated to the vertical position and fixed permanently in the floor of the sea Offshore mobile vessels have been developed to meet the needs of the offshore industry for a - - installation from which drilling, production or reconditioning operations can be carried out and which will usually remain in one place only while the operations are carried out, after which it can be moved to a different site. Several types of offshore mobile vessels have been developed to meet the needs of the industry including semi-submersible platforms and floating drilling boats for deep water operations, barges with pillars for inland waters or swampy arms and raised platforms with jacks for depths of water from small to moderate. The tower or drilling platform away from the coast raised with jacks includes a barge hull and support legs that are capable of being operated to lift the hull above the surface of the water. The hull of the barge can be towed like a floating boat from one place to another with its legs raised through the hull. Upon reaching the proposed location, the lift system will lower the legs through the hull of the barge until they are firmly attached to the seabed. Lifting with cats continuously descending on the legs will result in the penetration of the legs at the bottom of the sea until a foundation is achieved - - firm for the legs after which the continued lifting with jacks will cause the hull to rise above the sea surface to a height greater than the height of the highest wave anticipated during operations. Raised jack-lift systems conventionally include three or more legs, each leg consisting of one or more ropes, but more typically three ropes. One or more gear racks extend longitudinally along the length of the cords of each leg, and are driven by pinion gears fixed to the hull and energized by electrical or electromechanical hydraulic means in a manner well known to those skilled in the art. technique. The pinion gears can be positioned in such a way that the teeth of the pinion are oriented towards the center of a leg reinforced with multiple cords or can be oriented as opposed sprockets with a toothed rack mounted on each side of a leg or leg cord to engage the legs. opposing pinions. Multiple pinions are often stacked vertically to provide sufficient force to lift the desired loads. These drilling towers raised with jacks are subject to large environmental loads of storms that exert wind forces on the platform and wind and wave forces on the legs of the platform. A combination of these forces, together with the desired weight of the platform can result in a large interaction force between the platform and the legs that must be solved with the interface or connection of the leg with the helmet. To help reinforce and provide rigidity to the interface of the leg with the helmet, jacked towers are typically provided with jacks with the leg interlock systems that engage after the platform has been raised to its desired position or, in some cases, when storm conditions are anticipated. Leg locking systems of the prior art typically include elongated wedges having surfaces configured to conform to winds in the leg racks. The wedges are placed vertically in order to mesh with the teeth and then move horizontally by means of hydraulic cylinders, screw data, electric motors, etc. until they firmly attach a plurality of teeth to each string of each leg. Various types of mechanical and hydraulic means are then used to hold the wedges in a coupled position, so as to lock the legs in position as well as to provide rigidity to the raised structure and insulate the pinion gears load stress due to storm waves and the like. A major problem in these prior art structures is related to the need to properly vertically align the toothed wedges and the teeth of the racks on the leg cords before attaching the wedges. The pinion gears can place the legs vertically. However, since the legs are large, the individual rack teeth on the three apices of the leg may vary slightly from one another in vertical relation to the surface of the hull, due to manufacturing tolerances, imposed loads and similar factors. . It is not unusual, with the leg in a tight position, for the teeth of the zipper at an apex of the same leg vary vertically in relation to the hull, from those of another apex of the same leg by 2.54 to 7.62 centimeters, more or less through a vertical dimension of 30.48 centimeters of a typical tooth. Therefore, the matching engagement of the wedges with the teeth of the rack of the leg requires that means be provided for the limited vertical adjustment of the individual wedges relative to the body of the platform, in order to align the teeth of each wedge. or the teeth of one of the leg racks before matching the teeth of the wedge with the teeth of the rack. Several prior art foot interlocking systems have provided this function by including means for the vertical adjustment of the wedges relative to their support housings or structures mounted on the hooves and on the derrick after which the wedges are locked in its vertical position before horizontal coupling of the teeth of the wedge with the teeth of the zipper. With these systems, if the vertical adjustment of the wedges is carried out inaccurately, there may be a vertical misalignment between the teeth in the wedge and the teeth of the rack of the leg that will produce stress concentrations between teeth partially coupled which greatly reduces the effectiveness of wedges. Another problem presented by the leg interlocking devices of the prior art is their failure to accommodate manufacturing tolerances of the teeth in the rack of the leg. The zipper of the teeth of the rack for jacking up the legs of the derrick are cut with heavy steel plate flame guided by a physical template or computer control. Cutting heat and subsequent thermal treatment can cause distortions, producing teeth that can vary in - - size by as much as 3.18 millimeters through a typical tooth of 30.38 centimeters. Since it is desirable, in the leg locking systems, to have the toothed wedges engage at least four teeth of each leg rack, the accumulation of fabrication tolerance errors across the length of four teeth may be sufficient to cause the incorrect coincidence of some of the teeth, causing again stress concentrations that prevent the desired even distribution of the load forces through the coupled teeth. An additional problem with most of the prior art paw interlocking devices is that the devices, after being exposed to storm loads, may become locked and it may be very difficult to uncouple them when it is desired to release the interlocking systems. paw. Furthermore, some of the prior art systems rely on hydraulic forces to retain the wedges in mating engagement with the leg racks, which creates a risk of decoupling in the event that all power is lost on the platform.

OBJECTS OF THE INVENTION Therefore, a main object of the present invention is to provide a jack-up and improved platform interlock apparatus which overcomes or minimizes the difficulties inherent in the prior art. A further object of the invention is to provide an improved jack-up platform interlock apparatus that will securely engage the jack-up platform with the legs and, once it has been coupled it works independently of the mechanisms raised with jacks and that is simple and reliable to operate that is not subject to failure in case of loss of energy on the platform. A further object is to provide a jack-up platform interlock apparatus that provides vertical adjustment of the wedges relative to the teeth of the racks in a simpler and more reliable manner than the systems of the prior art. A further object is to provide a system in which a plurality of vertically aligned relatively short wedge segments are provided in each wedge unit each preferably engaging no more than two consecutive teeth of the corresponding leg rack in order to minimize The effect of - - Tolerance variations in the cut teeth with flame of the leg racks. A further object is to provide this system using hydraulically operated support wedges to position and hold the wedge segments horizontally and vertically for coupling coincident with the teeth of the rack and using self-locking horizontal screw mechanisms to mechanically interlock the support blocks and wedge segmenos in the coupled position, in order to minimize or eliminate having to depend on the hydraulic pressure to keep the system in locked position. A still further object is to provide this system in which support wedges and wedge segments can be quickly and easily uncoupled without the risk of inherently binding to prior art systems.

DRAWINGS These and other objects and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment thereof, which is taken together with the accompanying drawings and wherein: - Figure 1 is a plan view illustration of a raised pierced tower with jacks of the type wherein the leg locking system of the present invention could be used, illustrating three raised legs with triangular jacks and the placement of the leg racks and the pinion systems used to raise and lower the legs relative to the body of the derrick; Figure 2 is a fragmentary elevation view of a rope of a leg of the derrick raised with jacks of Figure 1, illustrating the relative positions of the elongated gear rack gear on the leg cords, and pinions raised with jack in the leg interlock units in accordance with the present invention; Figure 3 is a side elevational view showing half of a unit of the leg interlock system in accordance with the present invention coupling the teeth of the rack on a rope of the foot of the platform; Figure 4 is a side elevational view and partly in section of the unit of Figure 3 illustrating the jagged wedge segments and support wedges used for vertical and horizontal positioning and support of the wedge segments in the segments from - - wedge having been illustrated in a stored position not engaging the teeth of the leg rack; Figure 5 is an enlarged detailed sectional view taken along line 5-5 of Figure 4, and illustrating the details of the guide means for interconnecting the upper and lower jagged wedge segments; Figure 6 is a view similar to Figure 4, but showing the toothed wedges deployed to engage the teeth of the leg rack; Figure 7 is a fragmentary view, partly in section, taken generally along lines 7-7 of Figure 13 and illustrating the details of the arrangement of the interlocking chock and the shoe for locking the central support chock of the system in coupled position; Figure 8 is a partially sectioned fragmentary view taken generally along the lines 8-8 of Figure 13 illustrating the details of the hydraulic and mechanical system for positioning and locking in position, one of the support legs of the system; Figure 9 is a fragmentary partially sectioned taken along lines 9-9 of Figure 3 and - - which illustrates the details of the hydraulic system to place one of the jagged wedge segments of the system; Figure 10 is an elevational view partly in section taken along line 10--10 of Figure 6 and illustrating the additional details of the threaded choke retainer of Figures 8, 9; Figure 11 is a fragmentary view taken along line 11-11 of Figure 4 and illustrating the details of a gear arrangement for the threaded choke retainer of Figures 8 to 10.; Figure 12 is an elevation view similar to Figure 6, but showing elements of the system as they appear in the teeth of the rack of the leg and the teeth in the wedge segments were initially misaligned vertically, with the teeth of the rack of the leg being initially about 7.62 centimeters higher than the corresponding teeth of the wedges; Figure 13 is a view similar to Figure 12, but showing the system parts as they would appear if the rack teeth of the leg were initially approximately 7.62 centimeters smaller than the corresponding teeth of the wedge segments; - - Figure 14 is a simplified detailed view of an alternative guide means for interconnecting the upper and lower jagged wedge segments and the intermediate support chock segment of the system; Figure 15 is a view similar to Figure 6, but illustrating the toothed upper and lower wedge segments as well as the intermediate support chock which is provided with backup interlocking chocks; and Figure 16 is a view similar to Figure 6, but illustrating an alternative configuration for the intermediate support chock and wherein the anti-rotation guidance means shown in Figures 3 to 6 has been removed.

COMPENDIUM OF THE INVENTION The leg interlock system of the present invention uses a plurality of vertically aligned jagged wedge segments positioned longitudinally of each leg rack. Each of the wedge segments is relatively short in longitudinal dimension by preferably coupling not more than two teeth of the leg rack. The jagged wedge segments - - they have upper and lower inclined bearing surfaces that engage the forming wedges that hold the wedge segments. The support wedges allow the horizontal and vertical adjustment of the wedge segments to conform to the horizontal and vertical position of the corresponding rack teeth which are to be coupled by the wedges. Hydraulic double-acting cylinders are provided to move the wedge segments of the rack and its support wedges in alignment and coupling coincident with the corresponding rack teeth. Mechanical screw means and self-locking threads are provided to lock the coupled system in place, independent of the hydraulic pressure. Using a plurality of short, independently adjustable zipper segments, each preferably engaging no more than two teeth of the leg rack, enables the engagement of four or more teeth of the leg rack by means of rack wedge segments. aligned, while limiting the effect of dimensional variations on the individual rack teeth. Using the wedges for adjustment and horizontal and vertical support of the wedge segments of the rack reduces the risk of the parts to be linked and locked due to the load imposed during the use of the system, as well as reducing the force necessary to uncouple the system and return the pieces to the stored position where it is desired to release the legs of the derrick.

DETAILED DESCRIPTION Figure 1 illustrates in plan view, a drilling tower platform remote from the coast of the general type that can advantageously utilize the leg locking mechanism of the present invention. The platform 10 comprises a hull 12 of floating barge which can be self-propelled or towed to a desired location. The helmet serves to support and transport a plurality of legs 14 of the platform which, in the illustrated embodiment, comprise three triangular platform legs. The deck 16 of the platform is adjusted with the usual accompaniment of drilling equipment and / or offshore production such as a crane, drafting fittings, pipe zips, mud processing units, crew accommodation, heliport, lifting cranes, etc. Each of the three corners of the platform is equipped with a vertical well that extends through the hull that serves to receive in a guided manner one of the legs of the platform 14. Each - - One of the legs of the platform comprises three vertically extending ropes 18 which are structurally clamped together and joined by a lateral reinforcement 20 in an appropriate configuration. When the platform is moving from one place to another, the legs are carried in a raised position. The legs can be segmented with the segments of the leg being carried on the cover and then aligned and fixed to lower leg segments when it is desired to lengthen the legs. Once the platform reaches the desired location for operations, the hull rises above the surfaces of the water, raising the leg segments with cats until they reach the floor of the ocean. Once the supports at the bottom of each leg penetrate to sufficient load support layers, the continuous jack lifting of the leg units will lift the platform above the water to the desired operating height where the helmet will be free of coupling with the highest anticipated storm waves. A type of lifting mechanism with jack legs commonly used for which the present invention is particularly useful, is known as a lifting system with rack and pinion jacks. In this - - system, each rope of each leg includes a toothed rack 22 with double sides extending longitudinally and with a plurality of teeth 24 cut with flame. Opposing pinion gears 26 couple each side of each leg rack and mate the teeth of the rack. The hydraulic or electric drive mechanisms 27 carried by the platform energize the pinion gears for rotation in the desired direction to raise or lower the legs of the platform relative to the hull of the platform. Once the platform is at the desired elevation above the water, the operation of the pinions is discontinued. The pinion drive systems are self-locking design so that they will keep the platform in the desired elevated position. A plurality of leg interlock units 28 in accordance with the present invention is also carried by the platform. Each unit includes two vertically aligned gear wedge segments, each of which has teeth configured to conform to the teeth of the longitudinal leg rack. When the toothed wedge segments are coincidently and rigidly coupled with the leg racks, as described below, they serve to lock the leg against longitudinal movement relative to the platform hull and also to protect the oversized pinion gears, Bonding, deformation, etc. due to extreme conditions encountered during storms. Referring now to Figure 4, a single unit 28 for locking legs in opposite relation to one side of a longitudinal leg rack 22 is shown in the vacuum and partially in section. At least one of these leg interlock units would be placed on each side of each longitudinal leg rack. A lift with a three-legged crane that has triangular legs, therefore, would require eighteen of these units. The pieces are illustrated in the relative positions that they would adopt in the stored position (Figure 4) and in the unfolded position, locked position (Figure 6). Each leg interlock unit includes a rigid housing 36 carried by the helmet and adapted to properly support and guide the movable parts of the unit. The upper and lower horizontal bearing surfaces 37, 39 respectively, in the rear wall 41 and the opposite side wall portions (not shown) define a central opening in the housing 36 into which the active elements of the locking system are lowered.

These comprise a first segment of upper wedge 30, with two teeth 34 and a second segment 32 of lower wedge with two teeth 34. The upper and lower wedge segments are separated by an intermediate support bracket 38 of triangular shape. The support wedge 38 acts as a double wedge by engaging both the lower inclined surface 40 conformably configured in the wedge segment 30 and the upper inclined surface 42 in the wedge segment 32. The upper and lower wedge segments 30, 32 and the intermediate support wedge 38 are made of thick high-strength steel so that they can withstand the heavy mechanical loads imposed on the interlocking system by the legs of the platform 10. The inclination preferred between the inclined surfaces 40, 42 in the wedge segments and the double support chock 38 is such that the chocks and wedges are essentially self-locking in an uncharged condition. Anti-rotation guidance means may be provided to slidably interconnect the upper and lower wedge segments 30, 32. As shown in Figures 4 and 5, these comprise a pair of elongated guide members 43 one positioned on each side of the upper and lower wedge segments 30, 32 and encompassing the central chock 38. Each of the members 43 of - - The guide has inclined upper and lower guide surfaces in the shoulders 44 which engage and which are guided by guide grooves 45 that are conformably inclined in the wedge segments. Although not shown, the guide members 43 are held against offset outwardly from the guide slots 45 by sliding engagement with the housing portions of the wedge unit. The guide members 43 act as idler pinions in the slots 45 so that in the wedge segments 30, 32 move vertically towards or away from each other, and the guide members 43 will move horizontally as required to accommodate these movements verticals of the wedge segments. The engagement of the guide surfaces on the shoulders 44 with the guide grooves 45 provides an additional momentum lock for the wedge segments preventing any significant rotation of the wedge segments relative to one another and providing additional stiffness and strength to the wedge segments. total structure. The upper and lower support of the segments , 32 is provided by support wedges interposed between the wedge segments and the housing of the unit. The upper part of the wedge segment 30 is formed by a surface 46 inclined downwards. It is coupled by a lower surface conformably configured of a first upper support wedge that is restricted between the upper surface of the wedge segment 30 and the upper horizontal support surface 37 that forms the upper part of the housing opening. A surface 50 inclined upwards in the lower part of the lower wedge segment 32 engages a second restricted support or lower wedge 52 between the lower part of the wedge segment 32 and the lower horizontal support surface 39 of the housing 36. Again, even when any desired inclination can be used, the inclinations between the wedges and the upper and lower support wedges are preferably such that the parts are essentially self-locking in an uncharged condition. As will be apparent to those skilled in the art, the three support wedges 38, 48 and 52 allow for both vertical and horizontal adjustment and support of the wedge segments 30, 32. The wedge segments 30, 32 with their opposite inclined surfaces also function as shims, restricted between the opposing wedge surfaces in the support wedges 38, 48 and 52. As will be explained more fully below, this arrangement makes it possible for the almost infinite horizontal and vertical adjustment of the wedge segments 30, 32 within the parameters of the dimensions of the - - system in order to ensure an exact matching between the teeth of the wedge segments and the corresponding teeth of the rack 22 of the leg. However, once the teeth of the wedge segments are made to coincide with the teeth of the leg rack (Figure 6) and the chocks 38, 48 and 52 are coupled with their respective cooperating surfaces in the wedge segments and are retained against movement in a direction longitudinally away from the leg rack 22, then the entire system is locked rigidly and securely in place and the leg rack 22 can not move vertically with respect to the wedge unit until the legs are released. shims 38, 48 and 52. Positioning means are provided for moving the upper and lower wedge segments 30, 32 and supporting chocks 48, 52 horizontally within the housing 36 of the unit between stored and unfolded positions. In the preferred embodiment, these comprise two double-acting hydraulic cylinders 53, 54 each having its piston end fixed to one of the wedge segments and its end of the cylinder fixed to a box beam 57 forming part of the housing of the unit (Figures 3, 9). The positioning means for moving the upper and lower support brackets 48, 52 horizontally within the housing comprises a second pair of double-acting hydraulic cylinders 55, 56 each of which having its end of the cylinder fixed to the housing of the unit and its end of the piston fixed respectively to one of the blocks 48, 52 of upper and lower wedge (Figures 3, 8). The double-acting cylinders 53, 54, 55, 56 are preferably mounted slidable and pivoted in such a way that the vertical adjustment of the wedge segments and the supporting wedges upwards or downwards, at least to 7.62 centimeters in relation to the housing of the wedge unit is possible without being linked to the cylinders. The hydraulic lines 58 provide means for holding the hydraulic fluid under pressure to the end of the double-acting cylinders, while the hydraulic fluid is simultaneously discharged from the other end of the cylinder in order to cause a piston (not shown) in the cylinder moves the fixed wedge segment or block block horizontally towards or away from the rack 22 of the leg. A conventional hydraulic power unit 60 has a conventional control means (not shown) for selectively supplying the hydraulic fluid under pressure to either side of each of the cylinders to effect the desired horizontal movement of the wedge segments or the wedge members. . To illustrate the illustration, all the hydraulic lines are numbered "58" - - and only a single hydraulic power source 60 is indicated. However, it will be understood that separate hydraulic lines are provided on each side of each double-acting cylinder and that one or more of the hydraulic power sources and associated control means can be provided to energize and control each of the units. interlocking separately to control two or more of the units simultaneously, as desired. Threaded electrical, pneumatic, etc. placement means they could, of course, be replaced by hydraulic means made known. Retention means are provided for selectively retaining the three support wedges, once they deploy against horizontal movement in a direction away from the leg rack 22. As shown in Figures 4 and 6, an elongated hollow tubular spacer 60 is fixed to and horizontally moved with each of the upper and lower shims 48, 52. Referring to the upper chock 48, its associated spacer 60 extends between the rear part of the chock and a threaded platen 62, which screw-fit three elongated rods 64 rotatably mounted in the housing 36 of the chocking unit. A reversible hydraulic motor 66 drives a central gear 68 (Figure 11) which in turn drives three larger gears 70, one on top of each of the threaded rods 62 (Figure 11) to provide synchronized rotation in any direction of rotation. the three threaded rods. Since the plate 62 is screwed together with all three rods 64, rotation of the rods 64 in one direction will cause the plates 62, and the spacer 60 and the upper block 48 to move horizontally towards the rack 22 of the leg, while rotation on the threaded rods in the opposite direction will move the platen horizontally away from the leg rack 22, allowing the spacer 60 and the wedge 48 to move horizontally away from the gear rack by the double-action cylinder 55. Appropriate means are provided for selectively supplying the hydraulic fluid under pressure to the reversible hydraulic motor 66 in order to selectively rotate the threaded rods 64 in any direction. Although not shown, these means may comprise hydraulic fluid lines extending between the reversible hydraulic motor and the hydraulic power unit 60 and a control means (not shown) in the hydraulic power unit to selectively supply the fluid Hydraulic pressure on either side of the reversible hydraulic motor 66, as desired.

- Identical horizontal retention means are provided for block 52 of lower wedge. The retaining means for the double-acting central support chock 38 comprises a fifth double-acting hydraulic cylinder 72 (FIG. 7) that energizes a chock 74 of its lock fixed to the piston rod of the double-acting cylinder 72. The interlocking chock 74 couples a shoe 76 fixed to the housing 36 of the unit. The shoe 76 has an inclined surface 78 which cooperates with the inclined surface 80 of the wedge 74, while the opposite flat surface 82 in the wedge 74 engages the rear edge 84 of the central support wedge 38 to retain the wedge 38 in its unfolded position. or nailed. The respective inclinations in the shoe 76 and 80 in the wedge member 74 are shallow enough so that the wedge surfaces are essentially self-locking. This means that very little force is required in case the cylinder 72 is required in order to keep the chock 74 in place, when the system is in its deployed, locked condition. A mechanical interlocking mechanism suitable for this wedge could also be employed. Alternative designs for retaining means could be used with the desired function being to hold and lock the three support wedges in their deployed positions. Figure 15 illustrates an alternative embodiment of the leg interlock device of the present invention wherein the upper and lower wedge members 30, 32 are also provided with backup interlock wedges. As shown, the upper locking wedge 86 is positioned between the rear part of the upper wedge segment 30 and the shoe 88 carried by the housing of the unit, while the lower locking wedge 90 is placed between the rear part of the segment 32 of lower wedge and shoe 92 in the housing of the unit. Each of the additional locking wedges 86, 90 is activated by an additional hydraulic cylinder (not shown) as disclosed above in connection with the central locking wedge 74 (Figure 7). The manner of operation of the additional interlocking chocks 86, 90 is the same as that disclosed for the central locking chock 74. If the backup interlocking chocks are provided for each of the upper and lower wedge segments and the central support chock 38, then the provision of additional anti-rotation guidance means for the chock segments, such as the limbs 43 of guide - - elongate, usually would not be used and therefore, are not shown in Figure 15. Referring to Figure 14, another alternative embodiment of the anti-rotation guidance means for the upper wedge segments 30, 32 is disclosed. and lower. As shown in the detailed view, a vertical guide bar 94 which is preferably of generally rectangular cross-sectional configuration is slidably received in a conformably shaped passageway 96 that is formed vertically through the body of the intermediate support chock 38. The upper and lower ends of the guide bar 94 are adapted to be slidably received in substantially vertical recesses 98, 100 of conformable shape 98, 100 formed in the bodies of respectively the upper wedge segment 30 and the lower wedge segment 32. The clearances between the slidably coupled parts preferably allow a suitable independent adjustment of the upper and lower wedge segments 30, 32 and the central support chock 38 relative to each other and with respect to the teeth of the foot rack 22 allowing the teeth of the wedge segments to coincidentally fully engage the corresponding teeth in the leg rack, while accommodating the manufacturing tolerances in the teeth of the rack. The guide bar 94 - - it ensures, however, that the intermediate support chock 38 moves horizontally with the upper and lower wedge segments 30, 32 and further serves as a momentum interlock preventing any significant rotation of the wedge segments, one relative to the other. Referring to Figure 16, alternative configurations of the upper and lower wedge segments 30, 32 and the central support wedge 38 are shown. The changes comprise the provision of opposite shoulders 106 in the double shim 38 and 108 in each of the upper and lower shim segments 30, 32. The opposite shoulders serve to retain the double chock against backward displacement of the wedge segments of the shim. so that two wedge segments and double wedge will usually move as a unit. However, the double wedge 38 is preferably somewhat smaller than the space between the wedge segments so that the double wedge and the wedge segments have freedom for limited lateral and vertical movement with respect to each other. This allows the system to accommodate small dimensional variations between the two teeth of the rack coupled by the upper wedge segment 30 and the two rack teeth coupled by the lower wedge segment 32 to better match the distribution of force between the rack and pinion. Leg and wedges. In the modality shown in - - Figure 18, neither the elongated guide member 43 of Figures 3 to 6 nor the center vertical guide bar 94 of Figure 14, nor the additional backup locking wedges of Figure 15 are illustrated as being present. Of course, any of these supplementary antirotation means could be used with the configuration of Figure 16, if desired. When the system is in the stored position (Figure 4), the wedge segments 30, 32 center around the opening of the housing 36. In this position of preference there is at least a clearance of about 7.62 centimeters between the surface 37 of the housing upper and upper part of the wedge segment 30, and at least approximately a clearance of 7.62 centimeters between the surface 39 of the inner housing and the bottom of the wedge segment 32. As explained more fully below, this allows a total vertical adjustment of about 15.24 centimeters (about 7.62 centimeters from the centered position) of the wedge segments to accommodate misalignment between the wedge teeth 34 and the teeth 24 of the leg zipper. The center and longitudinal lines of the wedge segments 30, 32 and the shims 38, 48, 52 are preferably substantially aligned with the longitudinal center line of the rack 22 of - - paw. The hydraulic cylinders 53, 54, 55, 56 are pressed in a direction to retain the parts in their retracted stored position or the mechanical interlocking mechanisms such as the retaining pins (not shown) are provided for the wedge segments, so that the teeth of each of the wedge segments do not engage the teeth of the leg rack. If they are hydraulically secured, the means of preference are provided to maintain some pressure in the cylinders, while the pieces are in their stored position. This may comprise a control means (not shown) in the hydraulic power unit 60 to isolate the cylinders and their associated hydraulic lines so that pressure is maintained at an appropriate level on the appropriate sides of the cylinders to securely hold the parts in their stored positions retracted. A pressure accumulator (not shown) could also be provided in the hydraulic system for that object. The hydraulic cylinder 72 and its associated chock 74 are retracted and remain inactive. The plates 62 are retracted on their threaded rods 64 to allow retraction of the upper and lower support blocks 48, 52 and their associated spacers 60. When the coupling of the interlock system is desired, for example, when anticipated - In conditions of a storm, the three strings of each leg are preferably "strangled" one at a time. By selecting the cord to be sealed first, the vertical position of the leg rack and the wedge system for that cord are aligned by operating the pinion gears 26 to essentially align the teeth in the leg rack 22 for mating engagement with the legs. teeth in the wedge segments for the corresponding wedge unit. This can be done manually or preferably by means of vertical alignment sensors 102 mounted on the hull of the platform. One of these sensors is provided for each leg on the platform and is preferably placed on or near the cord of that leg to be stranded first. Sensors that are conventional in design are adapted to stop the platform elevation relative to the leg at a preselected point where the teeth on the leg rack of that leg cord will be essentially aligned for matching engagement with the teeth on the legs. centered stored segments of the two units for that leg cord. Although any desired type of vertical alignment means or sensors may be used, a preferred type is proximity sensors wherein a proximity meter carried by the helmet detects the proximity of each tooth crest to - - measure that passes through the meter, so that the crests of the tooth can be counted and accumulated to thereby allow the automatic elevation of the platform to a preselected vertical position on the legs. The operation of the pinions can then be stopped at a point where the crest of the tooth is essentially opposite directly to the proximity meter to ensure considerable vertical alignment of the rack teeth with the centered teeth of the wedge unit. Even when considerable alignment is desired, the wedge unit will accommodate the misalignment to the limits designed to the system which, for the preferable embodiment illustrated, is more or less than about 7.62 centimeters. Once the leg has been properly positioned, the cylinders 53 and 54 are supplied with pressurizing fluid in one direction to cause the two wedge segments 30, 32 to move towards the rack of the leg until the teeth of the segments wedge attach the teeth of the leg rack. The double support wedge 38 will advance with the wedge segments 30, 32. As the wedge segments 30, 32 advance toward the teeth of the rack, they will move down slightly in response to the inclination between the lower wedge segment 32 and the lower support block 52. Once the wedge teeth engage the rack teeth, the continuous pressure of the cylinders 53, 54 pushing the wedge segments towards the rack will cause the wedge teeth to slide up and inward in the tilt of the teeth 24 of rack until an almost perfect fit is achieved between the pawl rack teeth 24 and the teeth 34 of the wedge segment. The fact that the two wedge segments 30, 32 have some degree of movement independently of each other, within the tolerances of the interconnecting guide means, if used allows a more perfect match of the wedge teeth with the teeth of the leg rack, of what would be possible for a single wedge segment with four teeth. The effect of fabrication dimension errors on wedge and flame cut teeth, therefore, is limited to a scale of two teeth instead of accumulating through the vertical distance of four rack teeth. With the wedge segments continuing to be retained in closely mating engagement with the rack teeth by the cylinders 53, 54 the cylinders 55, 56 are supplied with pressurizing fluid in one direction to cause the two - - Support wedges 48, 52 move in firm support engagement with the wedge segments. This completes the basic alignment / coupling process. With the parts in their engaged position, the cylinder 72 is pressed in a direction to force the intermediate locking shoe 74 against the sloped surface of the shoe 76 by interlocking the intermediate support shoe 38 firmly in place. The upper and lower locking wedges 86, 90 if used are coupled in a similar manner. Then, the hydraulic motors 66 are used to move the plate 62 on the threaded rods 64 in contact with the hollow spacers 60. This firmly locks the upper and lower support wedges 48, 52 in place thus preventing the decoupling of the wedge segments 30, 32 from the toothed rack teeth. The self-locking threads between the plate 62 and the threaded rods 64 prevent decoupling until the rods are rotated by the motor 66 in the opposite direction. The pressure can then be released from the cylinders 53, 54, 55 and 56, since they no longer perform any holding function. While not absolutely necessary, it is desirable to maintain a certain pressure in the cylinder 72 as well as the cylinders for the upper and lower locking wedges 86, 90 if they are used in order to hold in place the chocks of interlock Since only a minimum pressure is needed, this can be achieved by adjusting the control means (not shown) in the hydraulic power unit 60 to lock the pressurizing fluid towards the cylinders. Alternatively, passive accumulator means may be provided to retain the pressure in the interlocking chock cylinders even when all the power of the hydraulic power unit 60 is interrupted. Alternatively, a mechanical interlocking device can be used for this same object. The steps just described will be carried out in sequence in each of the wedge units in each rope of each leg of the platform to securely lock the legs of the platform in place. Even when the wedge teeth and the rack teeth are essentially aligned for the first string, under the control of the vertical alignment sensors, the wedge teeth and the rack teeth on the other strings for that leg can be misaligned to some extent vertically due to manufacturing tolerances, strain deformation, etc. However, since each wedge unit accommodates vertical misalignment between its wedge segment teeth and the corresponding pin rack teeth, independently of the other wedge units, it is ensures a secure and nearly perfect fit between the wedge teeth and the rack teeth in the wedge unit, as long as the total misalignment of the leg cords does not exceed the vertical adjustment scale designed in the units. Referring to Figures 11 and 12, the relative positions of the wedge segments and block blocks are illustrated as long as the total misalignment of the leg cords does not exceed the vertical adjustment scale designed in the units. Referring to Figures 11 and 12, the relative positions of the wedge segments and the block blocks they would adopt when moving up (Figure 11) and down (Figure 12) by approximately 7.62 centimeters are shown in order to remain properly aligned with the teeth of the leg rack 22. The foregoing description and description of the preferred embodiment are illustrative and explanatory only and various changes in size, shape, materials and other details of construction and methods of operation may be made within the scope of the appended claims without departing from the spirit of the invention.

Claims (19)

CLAIMS:

1. A leg interlocking apparatus for a platform away from the coast of the type wherein a hull has a leg extending therethrough and a rack extending longitudinally on the leg with a plurality of longitudinally spaced rack teeth adapted to being coupled and driven by a pinion on the hull, the leg interlock apparatus comprises a wedge housing mounted on the hull; a plurality of vertically aligned wedge segments positioned in the housing, each wedge segment having at least one tooth adapted to coincidentally engage the teeth of the leg rack, each wedge segment having upper and lower inclined support surfaces, a plurality support wedge means in the wedge housing and adapted to conformably couple the upper and lower inclined bearing surfaces of the wedge segments to selectively support the wedge segments in the wedge housing; positioning means for moving the wedge segments and the support wedge means horizontally relative to the housing between the stored position in which the teeth of the wedge segments do not engage those teeth of the rack and an unfolded position in which the teeth of the wedge segments are intergraded with the teeth of the leg rack, and retaining means for selectively retaining the support wedge means in the deployed position.

2. The apparatus according to claim 1, wherein each of the segments has no more than three teeth adapted to coincidently engage the teeth of the leg rack.

3. The apparatus according to claim 2 wherein each wedge segment has two teeth.

The apparatus according to claim 1 wherein the retaining means is adapted to operate independently of the positioning means.

The apparatus according to claim 1, wherein the positioning means comprises a plurality of double-acting hydraulic cylinders, each cylinder having one end fixed to the wedge housing and the other end fixed to either one of the segments of wedge or one of the support wedge means.

6. The apparatus according to claim 1, wherein the support wedge means comprises intermediate and lower upper support blocks and wherein the retaining means comprise adjustable threaded supports with self-locking threads in order to selectively lock at least the chocks of upper and lower support in the deployed position. The apparatus according to claim 1, wherein the plurality of wedge segments comprise first and second wedge segments aligned vertically in the wedge housing and wherein the wedge means comprises a first support wedge positioned above and adapted to engage the upper inclined bearing surface of the first wedge segment, a second support wedge placed below and adapted to couple the lower inclined bearing surface of the second wedge segment and an intermediate support wedge placed between the first and second segments of wedge and adapted to conformably couple the lower inclined bearing surface of the first wedge segment and the upper inclined bearing surface of the second wedge segment. The apparatus according to claim 7, wherein the retaining means further comprises a wedge wedge wedge engageable with the intermediate support wedge to prevent horizontal displacement of the intermediate support wedge in a direction away from the teeth of wedge when the wedge segments are in the deployed position. The apparatus according to claim 8, further comprising a locking wedge selectively engageable with each of the upper and lower wedge segments to prevent horizontal movement of the upper and lower wedge segments in a direction away from the upper and lower wedge segments. Rack teeth when the wedge segments are in the unfolded position. 10. The apparatus according to claim 7, further comprising antirotation guiding means interconnecting the first and second wedge segments to prevent rotation of the wedge segments one relative to the other. The apparatus according to claim 10, wherein the anti-rotation guide means comprises an elongated guide member having an upper inclined guide surface and a lower inclined guide surface thereon, the upper inclined surface is adapted for coupling a conformal inclined guide groove in the - -

first wedge segment and the lower inclined guide surface adapted to engage a conformably inclined guide groove in the second wedge segment, whereby the vertical movements of the wedge segments relative to one another can be accommodated by movements of the guide member while the wedge segments remain essentially restricted against rotation relative to each other. The apparatus according to claim 10, wherein the anti-rotation guide means comprises an elongated guide bar positioned between and interconnecting the first and second wedge members, the upper end of the guide bar being adapted to be received within a generally vertical guide groove of conformable shape in the first wedge member and the lower end of the guide bar being adapted to be slidably received within a generally vertical guide groove in conformable form, the guide groove formed in the body of the second wedge member whereby the vertical movements of the wedge members relative to one another can be accommodated by the sliding movement of the guide bar in the guide grooves while the - -

first and second wedge members remain essentially restrained against rotation one relative to the other. The apparatus according to claim 12 further comprising a guide groove formed through the body of the intermediate support block essentially in vertical alignment with the guide grooves in the first and second wedge members and wherein the bar The guide is received slidably through the guide groove in the intermediate support block. 14. An apparatus for lifting the hull of a platform off the coast comprising: a toothed rack having a longitudinal axis and which is longitudinally fixed to the vertical leg extending through the hull; a drive pinion mounted on the hull and which engages to drive the teeth of the rack; means for rotating the pinion relative to the rack to effect the relative movement along the longitudinal axis of the rack to thereby move the helmet up and down relative to the leg; an interlocking mechanism for locking the leg against longitudinal displacement relative to the helmet, the locking mechanism comprising: a housing mounted on the helmet and having upper and lower bearing surfaces; first and second aligned wedge segments mounted in the housing between upper and lower support surfaces, the first wedge segment comprises a plurality of teeth adapted to coincidently engage the teeth in the rack, a top support surface inclined downward in a direction horizontally

10 remote from the wedge teeth and a lower bearing surface inclined upward in a direction horizontally away from the wedge teeth, the second wedge segment comprises a

A plurality of teeth adapted to coincidentally couple the teeth of the rack, a top bearing surface inclined downward in a horizontally fixed direction of the wedge teeth and a surface

20 of lower support inclined upwards in a direction horizontally away from the wedge teeth; a first support wedge placed between and conformably engaging the surface

25 upper support of the first wedge segment - -

and the upper support surface of the housing; a second support wedge positioned between and conformably engaging the lower bearing surface of the second wedge segment and the lower bearing surface of the wedge housing; an intermediate support wedge placed between and which conformably couples the

10 lower bearing surface of the first wedge segment and the upper bearing surface of the second wedge segment; a positioning means for moving the first and second wedge segments and the first and second support wedges horizontally in the housing between a stored position, wherein the teeth of the wedge segments do not engage the teeth of the rack, and a position displayed in

20 where the teeth of the wedge segments are intergraded with the teeth of the rack; and means of retention independent of the means of placement to retain the first and

25 second support chocks and support chock - -

intermediate in their deployed positions to thereby retain the first and second wedge segments in their deployed positions. 15. The apparatus according to claim 14 wherein the positioning means comprises a plurality of double-acting hydraulic cylinders. Each cylinder has one end fixed to the housing and the other end fixed to either one of the wedge segments or to one of the wedge segments. first and second support chocks. The apparatus according to claim 14 wherein the retaining means comprises threaded support means selectively engageable with the first and second support wedges to prevent displacement of the first and second support blocks deployed horizontally away from the wedge segments . The apparatus according to claim 16, wherein the retaining means further comprises a locking wedge selectively engageable with the intermediate support chock to prevent horizontal movement of the intermediate chock in a position remote from the teeth of the rack when the wedge segments are in the unfolded position.

18. The apparatus according to claim 14, further comprising interlocking chock blocks selectively engageable with each of the first and second chock segments to prevent horizontal displacement of the chock segments in a direction horizontally away from the rack teeth when the wedge segments are in the unfolded position.

19. The method for locking a leg of a raised platform with jacks against vertical displacement relative to the hull of the platform by crushing the teeth of a leg rack extending longitudinally of the leg, the method comprising: providing in the hull an apparatus Leg interlock comprising a wedge housing mounted on the hull, a plurality of vertically aligned wedge segments positioned in the housing, each wedge segment having at least one tooth adapted to coincidentally engage the teeth of the leg rack and each of the wedge segments has upper and lower inclined bearing surfaces, a plurality of wedge means of support in the wedge housing adapted to conformably couple the inclined bearing surfaces - -

upper and lower wedge segments in order to selectively support the segments in the housing, positioning means for moving the wedge segments and support means horizontally relative to the housing between a stored position in which the teeth of the segments the wedge teeth do not engage the teeth of the rack and an unfolded position in which the teeth of the wedge segments are interengaged with the teeth of the rack, and retaining means selectively retaining the support means in the unfolded position; align the leg and the leg rack in a desired vertical position with respect to the helmet; using the positioning means to move the wedge segments horizontally in the housing from the stored position to a position where the teeth of the wedge segments engage the corresponding teeth in the rack; using the positioning means to continue pushing the wedge segments into engagement with the teeth of the rack whereby the wedge segments in response to the thrust of the positioning means will move vertically and horizontally to achieve maximum mating engagement between the teeth of the zipper and the teeth of the wedge segments; using the positioning means to move the support means horizontally in the housing from the stored position toward the deployed position by engaging the bearing surfaces of the wedge segments to thereby hold the wedge segments against vertical and horizontal displacement relative to the gear rack; using the retaining means for retaining the support wedge means against movement in a direction horizontally away from the leg rack, and thereby retaining the teeth of the wedge segments in mating engagement locked with the teeth of the rack. gear.