US3435621A - Jacking system for offshore platforms - Google Patents

Description

April1,1969 RBJOHNSON I 3,435,621-

JAGKING SYSTEM FOR OFFSHORE PLATFORMS Sheet of3 Filed July 26, 1966 238 INVENTOR ROY B. JOHNSON April 1, 1969 v R. B. JOHNSON 3,435,621

JACKING SYSTEM FOR OFFSHORE PLATFORMS Sheet 2 M5 Filed July 26, 1966 INVENTOR ROY B. JOHNSON Apri11,1969 I R. B. JOHNSON 7 3,435,621

JACKING SYSTEM FOR OFFSHORE PLATFORMS Filed July 2e, 1966 Sheet of 5 INVENTOR.

ROY B. JOHNSON BY %M4Z M- ATTORNEY United States Patent Jersey Filed July 26, 1966, Ser. No. 567,887 Int. Cl. E02b 17/04; B66f 1/02, 3/46 U.S. Cl. 61--46.5 9 Claims ABSTRACT OF THE DISCLOSURE An offshore platform assembly comprises a platform, a plurality of spuds extending through openings in the platform for engagement with a supporting surface and a jacking mechanism associated with each of the spuds for effecting relative movement between the platform and spuds. Fluid operated jacks are pivotally mounted on the platform for engagement with the spuds and latch means pivotally mounted to the jacks for movement to and from said spuds. Means are provided for moving the jacks into holding engagement with the spuds and the latch means are operable to fix the longitudinal position of the jacks on the spuds.

This invention relates to a jacking system and more particularly to jacking assemblies or mechanisms used in conjunction with spuds or legs which support a platform, e.g., of the barge kind, employed for offshore operations, the jack being used for the purposes of elevating or lowering the platform and raising and lowering the spuds or legs relative to the platform.

The present invention constitutes an important feature in offshore, self-elevating platforms. Such platforms are large in extent, and consequently very heavy. A major requirement, therefore, is the provision of a reliable and fail-safe jacking system for effecting the desired raising and lowering, and locking of the platform in a selected operating position on its supporting columns or spuds. The jacking system must be able to accommodate a wide range of platfrom loads, e.g., operating equipment, and machinery, in addition to the weight of the platform. It must also accommodate a diversity of site environments and a variety of platform towing condiitons. The operation of offshore drilling platforms demands that the jacking system be durable, and that it operate quickly and efficiently in order to permit maximum on-site drilling time.

In essence, the invention provides a system including a hydraulic jack which is fail-safe and which is characterized by its high locking force between the relatively movable members of the jack. The jack of the invention incorporates an interference lock which offers infinite locking posiiton capabilities in the stroke of the jack thereby obviating the need for hard to handle shim mechanisms. This advantageous feature is due to the positive interlock which is inherent to the interference fit system in its at-rest condition.

It is a principal object of the invention to provide a fluid actuated, e.g., hydraulic, jacking system including a jack having an infinite position locking capability which comprises interference fit components.

It is a further object of the invention to provide a compact, dependable jacking structure which is relatively simple in construction and has a feature which affords a positive lock when pressure is relieved, either through failure of pressure or on command.

Further objects of the invention, which include various novel features of construction and assembly and which offer economy in manufactrue, dependability, simplicity and long life of components, will become apparent from Patented Apr. 1, 1969 the specification which follows when considered in conjunction with the various embodiments set forth in the drawings in which:

FIGURE 1 is a perspective view of a generally rectangularly shaped platform provided at each corner with a vertically movable spud, each having three legs which are extended and retracted relative to the platform by use of the jacking system embodying the invention.

FIGURE 2 is a side elevation of a platform supported by spuds comprising a single leg at each corner, which legs are provided with a jacking system constructed in accordance with the invention.

FIGURE 3 is a front elevational view, partly in section of a jacking system embodying the invention.

FIGURE 4 is a side view, partly in section of the structure shown in FIGURE 3.

FIGURE 5 are schematic representations illustrating sequences of engagement, extension, disengagement, retraction, etc. of the jacking system disclosed in FIGURES 2 and 3, relative to the leg or spud with which it coacts.

FIGURE 6 is a perspective view of a modified type of jacking system constructed in accordance with the invention.

FIGURE 7 is a sectional view of an interference fit actuator which forms a part of the jacking system embodying the invention.

Referring to the drawings, in FIGURE 1 a perspective view of a self-elevating platform 2 is shown. The plat form is provided at each corner with a spud 4. Although a generally rectangular platform is shown, it will be apparent that use of the jacking system of the invention is not limited thereto and any suitable platform configuratlon, e.g., a triangle, a square, pentagon or other convenient polygon, circle, oval, etc. shape may be used instead.

In the arrangement shown, each spud 4 comprises three legs 5 connected together by a suitable structural arrangement 6. Appropriately mounted on platform 2 and positioned to coact with each of the three legs to move the spud 4 up or down relative to platform 2 is a jacking assembly 8 (FIGURES 1, 3 and 4), whose features include a jack or actuator 10, including an interference fit lock 12, described in detail hereinafter in connection with FIGURE 7. This jack forms the primary means for providing the platform with a self-elevating capability. Also shown schematically in FIGURE 1 is a power supply S and control station C for operating the jacking system. The construction of the hydraulic system and electric apparatuses and controls referred to as power supply S, and control station C form no specific part of the invention. Therefore, only sufficient means to effect the controlled operation of the jacking assemblies is shown and described herein. A spud tank 14 of conventional design is mounted on the end of each spud 4 for the purpose of engaging and/or penetrating the ocean floor to support platform 2 in its operating position.

FIGURE 2 illustrates a platform provided with spuds which comprise a single leg 16. Each spud or leg 16, is provided with a single jacking mechanism or assembly 208 similar in construction and operation to that shown in FIGURE 6. The number of jacking assemblies required for a given platform depends upon the size and weight of the platform and the construction of the spuds required to support it safely for operation.

The elements comprising a jacking mechanism or assembly 8 and its relationship to a leg 5 are shown in greater detail in FIGURES 3-5 in which the jacking mechanism or assembly operates in a compression jacking system; that is, the jacks or actuators 10 of assembly 8 are provided to push platform 2 upwardly. Also, in the lowering of platform 2 or raising or lowering the spuds relative to platform 2, actuators 10 are in a compression state.

Referring to FIGURES 3 and 4 it will be seen that each jacking mechanism or assembly 8 comprises two actuators 10 spaced on opposite sides of leg 5. Each actuator is provided with a latch-link 20 connected to a common trunnion 22 suitably mounted on platform 2. The pivotal attachment of jack 10 and latch-link 20 to trunnion 22 is effected through a trunnion pin 24 supported in trunnion 22. At the lower end of jack extension rod 28 of jack 10 is a cross head. In the form of invention illustrated and described herein, this cross head is in the form of a yoke 26, the ends of which are pivotally attached to actuator rods 28 by connecting pins 30. Yoke 26 is provided with inwardly projecting jacking pins 32 which engage notches 34 of jacking bars 36 of legs 5. As shown herein, jacking bars 36 are attached to opposite sides of legs in any suitable manner, as by welding. Notches 34 can be cut or formed in bars 36 in any suitable conventional manner.

The upper ends of latch links 20 carry a cross head, which as illustrated herein comprises yoke 38, similar to yoke 26. Yoke 38 is pivotally supported at the upper ends of latch links 20 by means of connecting pins 49. Upper yoke 38 is provided with inwardly projecting pins 33 which, as in the case of pins 32 on lower yoke 22, engage notches 34 in jacking bars 36.

Yokes 26 and 38 can be of any suitable design, construction and shape. Yokes 26 and 38 can be formed as a single suitably shaped unitary member or form suitably shaped steel plates welded together. As shown herein they are generally U-shaped. This design allows their arms in effect to straddle legs 5 such that their locking pins 32, 33 can engage laterally spaced and aligned notches 34 of legs 5 (and 18) with which they coact.

The movement of jacks to effect the travel of yokes 26 and 38 relative to legs 5 such that pins 32 and 33 carried by these yokes can be moved into and out of engagement with selected pairs of laterally spaced notches will be described by reference to FIGURES 3 and 4. As shown, the cylinder end of a latch link pivoting actuator 42, which can be conventional design and construction, is pivotally attached to bracket 44 on plate 46 of trunnion 22 carried by platform 2. The rod end 48 of actuator 42 is pivotally attached to a bracket on latch link 20. An actuator 42 is operatively connected to each of the two latch links 20 of each jacking assembly 8. Coacting with each actuator 42 is a spring capsule 50. As best shown in FIGURE 4, the rod end 52 of each spring capsule 50 is pivotally connected to bracket 54 on the opposite side of latch link 20 from that to which the rod end of actuator 42 is connected. The cylinder end of each spring capsule 50 is pivotally attached to bracket 56 carried by plate 46.

As described more in detail hereinafter, actuators 42 operate to swing yokes 38 away from legs 5. Capsules 50 coact with actuators 38 to maintain pins 33 of yoke 38 in bearing relationship with portions 58 of bars 36, between notches 34, until pins 32 on yoke 38 move off portions 58, whereupon springs in capsules 50 force the yoke to the left, as viewed in FIGURE 4, thereby disposing pins 33 within a selected laterally spaced pair of notches 34 in bars 36.

Referring again to FIGURES 3 and 4, it will be seen that a second pair of actuators 62, which are similar in construction and operation to actuators 42, are provided to pivot jack 10 and yoke 26 carried thereby to and from a leg 5, thereby moving pins 32 carried by yoke 26 out of and into engagement with a selected pair of laterally spaced notches 34 in bars or rails 36 during jacking operations. Actuators 62 are pivotally attached at their cylinder ends to,brackets 64 on trunnion plate 66 on platform 2. Their rod ends are pivotally connected to brackets 68 on collars 70 suitably fixed to barrel 11. Spring capsules 74, similar in construction and operation to spring capsules 50, described hereinabove, coact with actuators 62 and effect the movement of jacking pins 32 on yoke 26 4 into jacking notches 34 by resiliently pivoting the lower end of jack 10 to the left, as viewed in FIGURE 4, about trunnion pin 24. The cylinder ends of capsules 74 are pivotally connected to brackets 76 on plate 66 on platform 2. The rod ends are pivotally secured to brackets 78 on collar 7 (l.

The jacking system operates by progressively jacking on longitudinally spaced notches 34 cut in rails or bars 36 attached to or otherwise suitably formed on the running length of and on opposite sides of legs 5 of spuds 4 which support platform 2. Rails or bars 36 provide the means for transferring loads through the notches. The space 58 on bars 36 between notches 34, as mentioned hereinabove, also affords a bearing surface for the latch link and actuator yoke pins 32, 33 on yokes 26 and 38, as they are moved between successive longitudinally spaced notches.

Actuators 42 and 62 are fluid, e.g., hydraulically operated and are double acting. Preferably they are operated in known manner by the controlled entry of fluid under pressure into the cylinder first through valves 81 and conduits connected to a suitable source of fluid supply 3 which effects the extension movement of pins 32 out of notches 34, and then through conduits 82 and valves 83 which causes a retraction of rods 48 and the movement of either yokes 26 or 38 towards legs 5, depending upon the stage of jacking operations.

Spring capsules 50, 74, which coact with actuators 42, 62 are provided with switches 84, 86. When the piston of spring capsule 50 (or 74) is in the position shown in FIGURE 4, it actuates a switch 84 (86) to cause the control circuit, which is provided for the jacking system (not shown) to indicate that pins 33 of yoke 38 (or pins 32 of yoke 26) are seated in their respective notches 34 and that jack 10 is in readiness to be operated. When the piston of spring capsule 50 (or 74) is fully extended or at its other extreme position, it closes the switch 88 (90) which causes the control circuit and power supply of the system to indicate that pins 32 on yoke 38 (26) have been moved clear of notches 34 and the jacking system now is operated to effect the movement of yoke 38 (26) upwardly or downwardly relative to its respective leg 5, in order to seat pins 32 thereon in the next selected upper or lower notches 34 on bars 36. It should be noted that spring capsules 50 and 74 are mechanical. Therefore, if there is any loss of power when pins 32 of either yoke 38 or 26 are positioned for entry into a selected set of notches 34, springs 92 of the spring capsules 50 and 74 insure that the desired movement of pins 32 into these notches takes place.

In jacking the platform disclosed in FIGURE 1 up or down it will be appreciated that since each spud 4 contains three legs 5, twelve jacking assemblies are provided. Generally, all twelve jacking assemblies are operated simultaneously to effect the desired relative movement between platform 2 and the spuds 4 at one corner of platform 2. However, if desired, the jacking systems for one spud or spuds at any grouping of corners can be operated independently as required, and the power supply S and electric control C are so designed as to make this possible and effect the desired controlled operations of the entire integrated apparatus.

In the platform shown in FIGURE 2, wherein a single leg 18 comprises a spud 4 one jacking assembly is provided for each spud. The construction and operation of the jacking assemblies, however, are the same.

Operation of the equipment shown in FIGURES 1-5 with specific reference being made to positions of jack in the schematic sequence shown in FIGURE 5 is as follows:

The jacking system operates by progressively jacking on notches 34 in rails or bars 36 legs 5 of spuds 4 which support platform 2. Rails 36 provide the means for transferring loads through the notches. Power supply S and control station C are provided with suitable electrical and/or fluid equipment including relays (not shown) and other components coacting with hydraulic valves in the fluid system including valves 49, 51, 53, 81 and 83. Fluid is obtained from source of supply 3 through suitable piping and conduits shown diagrammatically in broken lines in FIGURE 1.

FIGURE 5(a) illustrates schematically the condition of platform 2 and one of the several jacking assemblies 8 just prior to a jacking operation. FIGURE 5 (b) illustrates the next sequence of operation. When jack 10 has been stroked an appreciable amount, actuator 34 is activated and latch-link and upper yoke or cross head 38 are swung outwardly, and pins 33 on yoke 38 are moved clear of notches 34 in leg 5 of a spud 4. In FIG. URE 5(a) the operation of jack 8 continues and platform 2 is moved upwardly as indicated. Due to the movement of jack extensible rod 28 axially outwardly relative to jack 8, yoke 38 is moved upwardly relative to bars 36 on legs 4 and pins 33 bear upon portions 58. This action continues until, as shown in FIGURE 5 (d), latch links 20 are swung to the left by spring capsule 50 and actuator 42, and pins 33 are located in the next upper selected notch 34 of bars 36. Fluid pressure is then cut oil? in jack or actuator 8 and pins 33 of upper cross head 38 become seated in the lower portion of notches 34. Platform 2 is thereby raised one notch to its next selected position. As indicated, movement of jack extensible rod 28 with respect to jack 8 or any extension or retraction preferably is arranged to stop after engagement of pins 33 of upper yoke 38 in a next selected notch 34. Platform 2 now is supported through trunnion pin 24 by the structural connection formed by latch link 20. The lower portion of jack assembly 8 which carries cross head or yoke 26 now can be swung out by disengaging pins 32 on yoke 26, FIGURE 5 (d), and retracted, FIGURES 5(e) and (f), to engage the next above set of notches 34, FIG- URE 5 (g).

If only a single notch jacking operation is required, the operation of the jacks, actuators, spring capsules, power supply and control stop when the position of platform 2 or the spud relationship shown in FIGURE 5 (g) is achieved. However, jacking from notch to notch up or down can continue to any other required position required within the allowable limits of the equipment. Thus, upon engagement of pins 32 on yoke 26 with the next set of notches, jack extensible rod 28 is again commanded to unload pins 32 on upper yoke 38 so that latch links 20 can be pivoted or swung to the right as viewed in FIG- URE 5(b) in order to allow jack 8 to effect the movement of platform 2 relative to a spud 4 or leg 5. As shown in FIGURE 5 (g) both sets of pins 32 on yokes 26 and 38 are disposed properly within notches 34 and the platform is in a desired selected position. Obviously, the extent of movement of platform 2 upwardly or downwardly with respect to the spuds which support it, or conversely the movement of spuds relative to the platform depends upon the requirements of a given platform operating situation. The sequence described permits the spuds or links to be jacked to any desired position relative to the platform.

Actuators 42 and 62 preferably are hydraulically operated and operate in conjunction and in timed relationship with the actuation of a jack 8 in order to perform their required functions. By the continuous repetition of the above sequence, the jacking system is capable of manual or automatic operation. A simple reversal of the logic command signals of the control mechanism to effect the desired jacking and engaging operations of pins 32 enables the jacking system to lower, rather than raise platform 2, i.e., to raise spuds 4 or legs 5 with respect to the platform 2, as the case may be.

Referring again to FIGURE 5(a), during each operation of jacks 10, fluid under pressure is inducted into interference lock 12 of jack 8, described more in detail hereinafter, to unlock jack 8 and cause jack extensible rod 28 to extend slightly whereupon pins 33 of upper yoke 38 can be unseated and moved approximately centr-ally of notch 34. At this time, fluid under pressure is inducted through conduit of actuator 42 and acting upon the piston of rod end 48 of actuator 42. This actuator causes latch links 20 to swing to the right, as viewed in FIGURE 5 (b). At the same time jack extensible rod 28 is further extended so that, as shown in FIGURE 5, platform 2 is moved upwardly. At the same time that jack extensible rod 28 is being forced downwardly and axially relative to jack 10, fluid pressure in actuator 42 is either cut off completely or so reduced that springs 60' in spring capsules 50 force pins 33 of yoke 38 to bear upon and move along portions 58 on bars 36 such that when they reach the next notch spaced above the notch above the space from which they have just been disengaged, springs 60 effect their movement into this notch as shown in FIG- URE 5(d), If actuator 42 is still operating under reduced fluid pressure, this is now out off and pins 32 on yoke 38 are maintained positioned in their new notches 34 in which they become seated. Fluid pressure to lock 12 is cut off, whereupon the interference fit of lock 12 prevents any further axial movement of rod 28.

FIGURE 6 discloses a modified form of jacking system designed for use in a tension type of jacking assembly. This system is similar in many respects to that disclosed in FIGURES 3 and 4. The main difference is that the figures shown in FIGURE 6 is what can be termed a tension system in which the platform is pulled upwardly rather than pushed upwardly as in the case of the figures shown in FIGURES 1, 3 and 4.

Reference numerals applied to parts which correspond to similarly functioning parts in FIGURES 3 and 4 are distinguished therefrom by the digit 2; for example in FIGURE 6 jack 210 corresponds to jack 10 in FIGURES 3 and 4. As shown in FIGURE 6, jacking assembly 208 comprises a latch link 220. Jack 210 and latch link 220 are suitably mounted on platform 202 by means of trunnions 222 on pins 246 and 247 suitably supported in plates 249 of trunnions 222.

Actuators 242 and 262 are the same in construction and operation as actuators 42 and 62, described hereinabove. The cylinder ends of actuators 242 are pivotally connected to brackets mounted on trunnions 222. Their rod ends are pivotally connected to collar 270 fixed to jack 210 and to latch links 220, respectively. Fluid under pressure is introduced into actuators 242 and 262 by suitable pipe lines similar to pipe lines 80 and 82 provided for actuators 42 and 62. The cylinder ends of spring capsules 250 and 274 are pivotally connected to brackets at trunnions 222, and at their rod ends to latch links 220, and collars 270, respectively. Switches 288 and 290 carried by spring capsules 250 and 274 function in the same manner as switches 88 and 90 of spring capsules 50 and 74.

The free end of latch links 220' are pivotally connected to the arms of lower yoke 238. Each jacking assembly 208, as in the case of jacking assemblies 8 is provided with an interference lock portion 212 which contains an axially movable jack extensible rod 228. The free ends of rods 228 are pivotally connected to upper yoke 226. The arms of upper and lower yokes 238 and 226 are provided with inwardly extending pins 232 and 233 which engage notches 34 in bars or rails 236 of legs 16 of a spud.

The operation of the jacking system disclosed in FIG- URE 6 is essentially the same as that set forth hereinabove in describing the operation of the jacking system shown in FIGURES 1-5, inclusive and is omitted in the interest of brevity.

In each of the jacks or actuators described in the embodiment of FIGURES 1-5 and 6, an interference fit bearing lock coupling arrangement between telescoping parts is utilized. The structure of the interference fit actuator mechanisms for each of these embodiments is essentially similar, and will be described in connecting with the em- 7 bodiment shown in FIGURE 7. It will be understood that these interference fit couplings may be used with proper fittings in any of the jacks, and as such comprise an essential component of the jacks 10 and 210.

Referring to FIGURE 7, it is seen that the structure comprising the interference fit coupling involves an interference fit of a sleeve or barrel over a piston member contained therein with which it interlocks The members are uncoupled or separated at will by the introduction of a pressurized fluid at the interface between the sleeve and piston members thereby radially expanding the barrel or sleeve. As pressure is applied, this arrangement provides a fluid-static or fluid-dynamic bearing for low-friction movement. An important advantage of the mechanism resides in its fail-safe locking feature, i.e., when the pressure is relieved or when it fails the inner member and outer member concentrically fitted thereon interlock securely.

The area of overlap between two members which contains the interlock bearing need not necessarily be confined in a sealed arrangement but preferably it is suitably sealed off, as with O-ring seals located at the ends of the segment which includes the interfering surfaces. The diametral clearance at the O-ring or seal is within the limits for sealing requirements. The fit of that part of the surfaces between the O-rings which comprises the interference fit is shrunk fit or otherwise engaged at assembly of the sections so that when the two members are engaged, the interference fit between the two members provides the resistance to a given axial load. The resistance depends on the amount of interference. When the bearing surface is locked, the load is taken directly through the rod and cylinder acting as a rigid column. The interference fit arrangement as such, its function and the means for assembling the component parts thereof is described more fully in US, Patent 3,150,571.

In order to unlock the sleeve from its inner member with which it is locked, the overlapping section between the O-ring seals is pressurized by use of a fluid such as hydraliuc oil which is ported into the area and distributed at the bearing interface thereby effecting expansion of the sleeve. Suitable pressure may be supplied by a conventional pump, which may be a hand or foot lever operated, or mechanically and/or remotely actuated to feed or vent the pressurized fluid. The pressure build-up at the interface of the interference fit causes the outer section to expand until the interference tolerance between the members is overcome, i.e., the members are separated relative to the unpressurized state. The clearance or separation effected by the pressurization is still well within the confining capability allowable for the seals and the cylinder is relatively free to be translated with respect to the inner member with which it engages in interference fit in the unpressurized condition. The fluid as it is forced to separate the interface provides lubrication for the bearing surface.

In FIGURE 7, a jack or actuator 10 is assembled in combination with a valve control arrangement including valve (not shown), to deliver fluid and provide venting in properly timed sequence. The actuator 10 comprises an outer cylindrical sleeve conveniently fromed of two sections including the barrel 11 and the bearing or lock portion 12 of the barrel suitably joined together at 13. Centrally positioned within sleeve 167 is an inner element ram assembly which includes an extensible rod or piston rod 28, a piston head 29 in conventional relationship at one end and a rod eye 31 at the other end. One end of the barrel 11 is shown closed off by end cap 9.

The interference fit bearing lock section 12 which forms the bearing lock assembly for the mechanism includes a locking bearing surface or interface 35 constructed and arranged to provide an interference fit between the inner surface of the bearing part 35 of interference lock section or sleeve 12 and the outer periphery of inner member 28, i.e., the elements 28 and 12 are dimensioned so as to mechanically lock in the absence of pressurization at the intrface to disengage the interference.

As shown, the bearing portion of the sleeve 12 may be attached to barrel 11. This construction shows the connection of separate pieces. However, it will be apparent that barrel or sleeve 11 and bearing portion of the sleeve 12 may be integrally formed and may be of uniform diameter where this is more convenient, desirable or practical and in such situations the joint at 13 is obviated. Static seals 37 are provided at each end of the barrel 11 to contain the pressurized fluid in a manner conventionally employed to move actuator rod 28. Dynamic seals 39 prevent oil or other fluid employed to drive the piston from flowing across the piston.

In order to confine bearing release fluid within the bearing area, dynamic seals 41 and 43 are provided. An conventional pressurized fluid source in combination with a control valve arrangement may be provided to permit operation of the assembly. This arrangement comprises the usual means for extending and retracting piston 29 through pressurization introduced under control of valves 49 and 51 at or 47 when the bearing is unlocked by suitable pressure applied by way of valve 53 through port 55. Actuator or piston rod 28 may be moved in one direction by feeding fluid at 45 while venting at 47. This moves the piston member 29 to the right, as viewed in FIGURE 7. For the reverse movement, pressurization at 47 while venting at 45 effects movement of member 28 to the left.

Reference is now made to the interference fit locking hearing or interface 35. In the absence of pressure, the bearing is at rest in a mechanically locked position effected by an interference fit between the inner surface of lock portion 12 of jack 10, and the outer surface of rod 28. The quantum of force locking the members 12 and 28 at the bearing lock interface 35 is dependent on the extent of interference in the bearing fit. To unlock this mechanical coupling, fluid under pressure is introduced through valve 53 to the bearing interface of 35 through port 55 employing suflicient pressure to effect a relative separation between these surfaces but insuflicient pressure to exceed the elastic limit of the sleeve expansion. This separation of the interface allows the piston rod 28 to move freely with respect to the outer member 12 using a conventional actuating force, e.g., fluid pressure applied on the piston 29, by fluid under pressure introduced through port 45 or port 47 under control of valves 49 and 51, respectively, in the fluid line from source of fluid supply 3 and pumps (not shown) of the hydraulic system of power supply S. It will be appreciated that all of the jacks 10 are operated in this same manner.

As shown in FIGURES 3 and 4 each trunnion 22 comprises vertically spaced horizontal plates 46, 66 suitably attached, as by welding, to platform 2, and horizontal vertically intermediate plates 57.

Plates 59 are suitably secured, as by welding, to plates 57. Suitable elastomeric shock pads 61 of conventional design are interposed and suitably mounted between plates 46 and 57 and 66 and 57 to absorb shocks which occur during the jacking operation and when platform 2 is in use. Pads 61 can be commercially obtainable Neoprene/aluminum laminated sheets. The Neoprene is a to 70 durometer. These pads can be obtained from Continental Rubber Works, Erie, Pa., or Goodyear Tire and Rubber Co., Akron, Ohio. Trunnions 222 shown in FIGURE 6 also support elastomeric pads 261 which function in a manner similar to pads '61.

From the above description it is apparent that the operation of the jacking asemblies required for the elevation of platform 2 relative to spuds 4, or conversely, can be effected automatically or manually, as desired. All of the actuations necessary to the operation of the jacking assemblies are so timed that the extension and/ or retraction of the jack extensible rods occurs when each jack 10 is pressurized so as to interrupt the interference fit at interface 35. So also the operation of actuators 42 and 9 62 are so controlled that they operate in timed relationship during the unlocked state of each jack in order to effect the purposes of the invention.

It will be apparent to those skilled in the art that various modifications may be made in the invention without departing from the scope of the invention. Accordingly, the invention is not to be limited except insofar as necessitated by the appended claims.

What is claimed is:

1. An apparatus of the type described comprising a generally horizontal platform, a plurality of spuds extending downwardly from said platform for engagement with a supporting surface, a jacking mechanism associated with each of said spuds for effecting relative raising and lowering movements between said platform and spuds, said mechanism including at least one fluid operated jack coacting with each spud, means pivotally mounting each of said jacks on said platform for movement to and from said spuds, latch means pivotally mounted to said jack for movement to and from said spuds, means for selectively moving said jacks on their pivots to and from their respective spuds and into holding engagement with their respective spuds, said latch means being operable to fix the longitudinal position of said jack on said spud when the jack is pivoted away from said spuds, and means for locking said jacks against movement when a selected positioning has been effected between said platform and spuds, said locking means comprising an interference fit coupling between the actuator components of said jacks whereby upon release of pressure in said jack said actuator components are locked against movement.

2. The invention defined in claim 1, wherein said spuds comprise at least one elongated leg provided with notches spaced equidistantly therealong, said latch means having pins operable to engage and seat in selected notches in said legs when pivoted theretowards, and said jack includes a cross head at the end opposite to said latch means having pins adapted to engage and seat in selected notches in said legs.

3. The invention defined in claim 2 wherein said cross heads are yokes having arms straddling said legs and said pins are carried by the arms of said yokes and are located such that they engage and seat in laterally spaced pairs of notches of said legs.

4. The invention defined in claim 3 including fluid operating actuators for moving said jacks to move said pins on said yoke arms out of one set of notches of said leg, means for stroking said jack to travel said yoke along said leg to other selected notches spaced from said first named notches, and resilient means for moving said jack in such manner that said pins on said yoke enter and become seated in said selected notches of said leg.

5. The invention defined in claim 4 including means for pressurizing said jack to release said interference fit coupling, and fluid operated extensible means for effecting said travel of said yoke of said jack along said leg operable while said coupling is unlocked.

6. A jacking arrangment for elevating and supporting a platform in locked position on legs comprising: a platform; legs therefor capable of supporting said platform; said legs being provided with substantially equally distant jack engaging notches extending the length thereof; a fluid operable jack effecting the relative movement between said platform and legs; said jack arranged to be engageable intermittently in controlled sequence in said notches, latch means mounted to said jack and pivotal into and out of engagement with said notches, said latch means being biased toward said notches, said jack including an interference fit coupling between the actuator components of the jack which provides the power stroke for the jack; means for introducing fluid under pressure to the interface of said interference fit coupling to effect a relative separation and unlocking of said actuator components of the jack, means for stroking the jack when said interference fit coupling is unlocked by fluid pressurization; means for pivoting said latch means out of engagement with one of said notches during the initial portion of the stroke of said jack, a source of fluid pressure for said interference fit interface and for stroking said jack; means for operably engaging said jack with said notches on the legs to effect relative movement between said legs and platform during the stroking operation of said jack, and said interference fit coupling between the actuator components of said jack being operative to lock said platform and legs against relative movement whereby said platform is secured in a selected operating position on said leg.

7. An apparatus of the type described comprising a generally horizontal platform, a plurality of spuds extending downwardly from said platform for engagement with a supporting surface, each of said spuds having at least one leg provided with equidistant jack engaging notches therealong, a jacking mechanism associated with said leg spuds for effecting relative raising and lowering movements between said platform and spuds, said mechanism including two fluid operated jacks coacting with said leg, one being located on opposite sides of said leg, and including an extendible rod, means pivotally mounting said jack on one side of said leg for movement to and from said leg, a cross head carried by the free end of said jack, for selectively positioning said cross head in holding engagement with selected notches in said legs, latch links having one end pivotally mounted on said platform, a second cross head carried by the free ends of said latch links and disposed on the opposite side of said platform, means for effecting the controlled movement of said latchlinks to and from said leg in timed relation to the operation of said jacks to cause said notch engaging means on each of said cross heads to be moved alternately into and out of selected notches in said leg on opposite sides of said platform whereby relative upward or downward movement between said platform is accomplished, means for locking said jack against movement when a selected positioning has been effected between said platform and spuds, said locking means comprising an interference fit coupling between the actuator components of said jacks whereby upon release of pressure said actuator components become locked against movement means for introducing fluid under pressure into said interference fit locks of said jacks to unlock said interference fit coupling, and means for extending or retracting said extensible rod while said coupling is unlocked whereby relative vertical movement between said platform and spuds is effected.

8. The invention defined in claim 7 wherein said jacks extend downwardly below said platform and said latch links extend upwardly above said platform, whereby said platform is pushed upwardly relative to said legs when said jacking system is operated.

9. The invention defined in claim 7 wherein said jacks extend upwardly above said platform, and said latch links extend downwardly below said platform, whereby said platform is pulled upwardly relative to said legs when said jacking system is operated.

References Cited UNITED STATES PATENTS 2,947,148 8/1960 Young 61-465 3,150,571 9/1964 Frassetto et al. 9228 3,259,368 7/1966 Warnke 6l46.5 X 3,332,663 7/1967 Cargile 6146.5

JACOB SHAPIRO, Primary Examiner.

US. Cl. X.R. 254-106, 107, 119

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