US3918379A

US3918379A - Gimbal support system for deep ocean mining vessel

Info

Publication number: US3918379A
Application number: US479155A
Authority: US
Inventors: James F Mcnary; Edward C Hicks; Yilmaz H Ozudogru
Original assignee: Global Marine Inc
Current assignee: Global Marine Inc
Priority date: 1974-06-13
Filing date: 1974-06-13
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11

Abstract

A gimbal-mounted heave-compensated stable platform for a surface vessel from which deep ocean mining equipment is lowered, operated, and raised. The platform, which provides a stable base for a derrick and heavy lift apparatus, is supported with minimal friction, by a pair of spaced vertical guide frames mounted on the vessel. A gimbal support member is vertically movable in each of the guide frames. The heave control system controls the position and movement of the support members relative to the guide frames. A gimbal frame is rotatably supported on the gimbal support members by anti-friction bearings for rotation about a first axis. The stable platform is in turn rotatably supported on the gimbal frame by anti-friction bearings about a second axis of rotation perpendicular to the first axis. Variable length snubbing members mounted on the gimbal frame engage the platform at extreme angles of rotation of the platform about the second axis. Additional variable length snubber members mounted in fixed relation to the vessel engage the platform when the platform rotates to extreme angles in either direction about the first axis.

Description

[ Nov. 11, 1975 [57] ABSTRACT A gimbal-mounted heave-compensated stable platform for a surface vessel from which deep ocean mining equipment is lowered, operated. and raised. The platform, which provides a stable base for a derrick and heavy lift apparatus, is supported with minimal friction, by a pair of spaced vertical guide frames mounted on the vessel. A gimbal support member is vertically movable in each of the guide frames. The heave control system controls the position and movement of the support members relative to the guide frames. A gimbal frame is rotatably supported on the gimbal support members by anti-friction bearings for rotation about a first axis. The stable platform is in turn rotatably supported on the gimbal frame by antifriction bearings about a second axis of rotation perpendicular to the first axis. Variable length snubbing members mounted on the gimbal frame engage the platform at extreme angles of rotation of the platform about the second axis. Additional variable length snubber members mounted in fixed relation to the ves- GIMBAL SUPPORT SYSTEM FOR DEEP OCEAN MINING VESSEL Inventors: James F. McNary, Pacific Palisades;

Edward C. Hicks, Santa Ana; Yilmaz H. ()zudogru, Los Angeles, all of Calif.

Assignee: Global Marine Inc., Los Angeles,

Calif.

Filed: June 13, 1974 Appl. No.: 479,155

US. 114/.5 D; 175/5; 175/ Int. B63B 35/44; B63B 35/00 Field of Search.......... 114/.5 D; 9/8 P; 61/465; 166/05; 75/5, 7, 27

References Cited UNITED STATES PATENTS United States Patent McNary et al.

sel engage the platform when the platform rotates to extreme angles in either direction about the first axis.

8 Claims, 7 Drawing Figures ll4/.5 D

Deal. Jr. et al. Bromell et al.

Primary Eraminer-Trygve M. Blix Assistant E.\'aminerSherman D. Basinger Attorney. Agent, or FirmChristie, Parker & Hale Sheet 1 of 5 3,918,379

U.S. Pa tent Nov. 11, 1975 US. Patent Nov. 11, 1975 Sheet2of5 3,918,379

Patent Nov. 11, 1975 Sheet 3 of 5 US. Patent Nov. 11, 1975 Sheet4of5 3,918,379

US. Patent Nov. 11,1975 Sheet50f5 3,918,379

1" GIMBAL SUPPORT SYSTEM FOR DEEP OCEAN MINING vEssEL FIELD OF THE INVENTION BACKGROUND OF THE INVENTION In copending' application Ser. No. 479,091, filed June 13, 1974, entitled Apparatus for Raising and Lower" ing Pipe String From a Floating Vessel in the names of Robert Curtis Crooke andAbraham Person, as inventors, and assigned'to the same assignee as thepresent application, I there is described a heavecompensated heavy lift system for raising' and lowering deep ocean mining equipment by'means of a string of pipe. The equipment, including a derrick for handling the pipe sections, is supported on a gimbal structure which permits the pipe string to be moved vertically while isolated from the roll, pitch, and heave of the associated surface vessel. It is necessary in such a system to be able to rapidlyarrest excessive movementsof the gimbal system in the event the pipe string should break and otherwise minimize damage to the pipe or other structure in the event of excessive gimbal "motion. It is also necessary to providesome means of locking up the gimbal system when the vessel is underway.

SUMMARY OF THE INVENTION The present invention is directed to a gimbalmounted. stable platform structure for use on a deep ocean mining vessel on which controllable soft stops are provided foradjustabl y limiting or preventing rolling and pitching of the stable platform without interfering with the heave-compensation control.

In brief, this is accomplished by providing, ina deep oceanmining vessel, a stable base comprising a pair'of vertical guide frames mounted on the vessel, a'pair of gimbal support members movable vertically on there spectivelguide frames, heave-control means controlling the position and movement of the gimbal support members relative to, the guide frames, a gimbal frame, means rotatably supporting the gimbal frame on the gimbal support members forrotation about a roll axis, platform means, and"m'eans rotatably supporting the platform means on the gimbal frame for "rotation about a pitch axis. Anti-friction bearings in both the pitch and roll axes provide minimum resistance'support for the platform to protect the string of pipe from induced bending movements. Means for controlling the rotation of the platform about the pitch axis includes two or more variable length snubbing members mounted on the gimbal frameand engaging the platform at widely spaced pointson either'si'de'of thepitch axis, the snubbing members being variable in leng thin a direction substantially perpendicular to the. plane defined by the first and second axes, whereby changing tl' eJlength of the snubbers controls the limits of movement of the platform about the pitch axis. Means is also provided for controlling rotation of the platform and gimbal frame about the roll axis including at least two variable I length snubbing members mounted directly to the fives I sel, the snubbing members being .variable'in length in a direction substantially horizontal relative tothe vessel. The platform includes a pair of substantially vertically extending surfaces which frictionally engage the snubber means with rotation in either direction about the roll axis and within the full range of vertical movement of the platform.

: BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference should be made to the accompanying drawings, wherein:

FIG. 1 is a perspective view of an ocean mining vessel incorporating the features of the present invention;

' FIGS. 2A and 2B are a front elevational view partly in section of the gimbal-supported stable platform;

FIG. 3 is a side elevational view partly in section of the gimbal-supported stable platform;

FIG. 4 is a top view of the gimbal system; and

' FIGS. 5 and 6 are side views of the gimbal system.

DETAILED DESCRIPTION Referring to FIG. 1, the numeral 10 indicates generally a ship designed to incorporate the features of the present invention for use in subsea mining operations. The ship is provided with a moon pool 12 located amid ships which gives access to the water and the ocean floor. 'Mining equipment (not shown) can be stored in the large Opening of the moon pool during transit and can belowered from the moon pool 12 to the ocean floor by 'a string of pipe which is assembled in sections and raised or lowered by a pipe-handling system, indicated generally at 14. The pipe-handling system includes an A-fr'ame base 16 which bridges the moon pool 12 amidships of the vessel 10. A derrick 18 is supported Over the moon pool on the A-frame 16 through a gimbal system 20 which permits the derrick to maintain a vertical position even though the ship may be rolling or pitching.

' Referring to FIGS. 2 and 3, the pipe-handling system 14 is shown in greater detail. The A-frame 16 is supported from the main deck 22 of the ship 10 by four support pedestals 24. The 'A-frame support structure 16 includes a pair of end trusses 26 and 28 which bridge the moon pool between the support pedestals 24. The trusses 26 and 28 are tied together by horizontal girders 30 and 32 adjacent the top of the trusses, the girders 30 and 32 being spaced apart to leave an opening through which the lower end of the derrick structure 18 extends.

To provide heave compensation, the gimbal system 20 on which the derrick 18 is mounted is supported on the A-frame 16 by an arrangement which permits relative vertical movement between the ship 10 and the gimbal system 20 on which the derrick is supported. As seen in FIG. 3, the trusses 26 and 28 have vertically extending

frame members

38 and 40 which provide vertically extending

guide surfaces

42 and 44, respectively. Movable in the guide surfaces 42 of the guide member 38 is a gimbal bearing yoke 46, while a similar gimbal bearing yoke 48 is vertically movable in the guide 44 of the guide member 40. I-Ieave compensating rams, indicated generally at and 52, provide an adjustable "support between the bottom of the

yokes

46 and 48 and abase frame portion 53 of the trusses 26 and 28 of the A-frame structure 16.

The

yokes

46 and 48 respectively support axially outer gimbal frame 58 by means of

bearings

61 and 63.

The outer gimbal frame 58 is an open rectangular structure. An inner platform frame 60 is in turn supported within the outer gimbal frame 58 by means of

coaxial stub shafts

62 and 64. These shafts are journaled in

bearings

66 and 68 mounted on opposite sides of the outer gimbal frame 58. The derrick 18 is supported on the top of the platform frame 60. The derrick includes a rig floor 70 which in turn is supported on four legs 72 at each of the corners to the top of the inner gimbal frame 60.

Supported below the derrick floor 70 within and below the inner platform frame 60 and extending down into the opening through the A-frame support 16 is the heavy lift equipment by means of which a pipe string can be raised and lowered through the moon pool to and from the ocean floor. This heavy lift equipment includes a pair of upper hydraulic cylinders 74 and 75 mounted on the platform frame 60 on either side of the vertical centerline along which the pipe string is raised and lowered. See FIG. 3. The cylinders 74 and 75 operate vertically extending piston rods 76 and 77 which extend downwardly and are joined at their lower ends to a bridging upper yoke assembly 78. The upper yoke assembly 78 includes hydraulically operated means for releasably gripping the pipe string at a pipe joint so that hydraulic actuation of the upper cylinders 74 and 75 imparts vertical movement to the pipe string.

Extending down beneath and supported from the platform frame 60 is an open cage structure 80 which terminates at its lower end in a lower platform 82 on which are mounted two lower hydraulic cylinders 84. The cage structure is constructed of a suitable frame work to provide a rigid support for the lower platform 82 from the frame 60. The lower hydraulic cylinders are positioned fore and aft of the vertical centerline, whereas the upper hydraulic cylinders 74 are located to starboard and port of the vert.;.1l axis. The lower cylinders 84 actuate piston rods 86 which are coupled at their lower ends to a lower pipe-gripping yoke assembly 88. Like the upper yoke assembly 78, the lower yoke assembly 88 is also arranged to releasably grip the pipe string at a pipe joint. Thus hydraulic actuation of the lower cylinders 84 likewise is capable of imparting a lowering or raising motion to the pipe string. The lower end of the cage structure 80 is provided with ballast, as indicated at 90, for the purpose of lowering the center of gravity of the derrick and associated heavy lift system to a point below the plane of the gimbal axes. The derrick therefore tends to ride in a vertical position within the gimbal support under the influence of gravity, substantially isolated from the rolling and pitching movement of the ship.

The present invention provides a roll soft system to snub down or limit the amount of roll experienced by the gimbal supported derrick and heavy lift system relative to the vessel. The roll soft system includes hydraulic cylinders 96 and 98. The hydraulic cylinders are rigidly supported on the A-frame structure 16 by suitable mounting brackets 100 and 102 extending between the A-frame trusses 26 and 28. The hydraulic cylinders operate cylinder rods 104 and 106, respectively, which project inwardly on either side of the cage structure 80. The inner ends of the cylinder rods 104 and 106 have ball-mounted pedestals 108 and 110 providing stop members which are moved into engagement with the opposite walls of the cage 80 on extension of the rods 104 and 106 by the hydraulic cylinders 96 and 98. The

sides of the cage provide a relatively smooth surface for sliding engagement with the pedestals to permit relative vertical movement between the cage 80 and the pedestals with heave motion of the vessel relative to the gimbal-supported heavy lift system. The rods 104 and 106 can be adjustably positioned by hydraulic controls (not shown) to limit the lateral movement of the cage 80 relative to the vessel as it swings about the roll axis of the gimbal support. Movement of the pedestals 108 and toward each other snubs the roll motion of the gimbal-supported structure. By bringing the rods 104 and 106 to their full extension the cage 80 can be held in a neutral roll position. By partially extending the cylinder rods 104 and 106, the angular swing of the gimbal-supported cage 80 relative to the ship can be limited to any selected angle within the maximum limits of movement of the system.

Once the cage 80 is brought to a neutral position by the cylinders 96 and 98, the gimbal system can be locked to prevent any movement about the roll axis. To this end, as shown in FlGS. 4, 5, and 6, four roll and heave locking units, indicated generally at 112, 114, 116, and 118, are provided. The locking unit 112 includes a hydraulic actuator which moves a locking pin 122 selectively into and out of engagement with the stop lug 124 projecting from the side of the vertically extending frame member 38. A similar lug 126 projects from the opposite side of the vertical frame 38 where it is engaged by the locking unit 1 14. Similarly, lugs 128 and 130 project from either side of the vertical frame 40 for engagement by the locking units 116 and 1 18 respectively. The detent pin 122 is slidably supported on the top of the gimbal frame 58 by a housing 132 extending between

support brackets

134 and 136.

With the detent pin 122 retracted in each of the locking

units

112, 114, 116, and 118, the gimbal frame 58 is free to move vertically to compensate for heave motions of the vessel and to rotate freely on the roll

axis supporting bearings

61 and 63. With the detent pin 122 of the locking units extended, the heave compensation system can be used to lower the detent pins onto the respective stop lugs 124, 126, 128, and 130, thus providing a rigid support for the gimbal frame 58 on the

vertical frame members

38 and 40. Additional sets of four lugs may be provided at different vertical positions on the

vertical frame members

38 and 40, thus permitting the gimbal frame 58 to be locked at any one of several vertical positions relative to the vessel.

In addition to the snubbing action and the roll and heave locking system described above, there is also provided a pitch soft system for snubbing the relative movement of the gimbal-supported structure about a pitch axis. Also a pitch locking system is provided for locking the platform 60 to the gimbal frame 58. The pitch soft system includes four hydraulic cylinders vertically mounted to the inside of the gimbal frame 58. As previously described, the stable platform 60 is rotatably supported within the gimbal frame 58 by

stub shafts

62 and 64 which are joumaled in

anti-friction bearings

66 and 68, the bearings being mounted in the gimbal frame 58. The platform 60, as shown in FIG. 4, is substantially H-shaped with four arms extending into each corner area within the substantially square open gimbal frame 58. The four legs 72 at the base of the derrick are mounted on the outer ends of the projecting arms of the H-shaped platform 60. Pitch

soft snubbing cylinders

140, 142, 144, and 146 are respectively positioned adjacent the corners of the gimbal frame 58 below each of the projecting arms of the platform 60 and mounted to the inside wall of the gimbal frame. The hydraulic cylinder 140 actuates a piston rod 148. Mounted on the end of the rod 148 is a ball-mounted pedestal 150 which engages the underside of one arm of the platform 60. Similarly, each of the

other cylinders

142, 144, and 146 includes an extensible piston rod and associated ball-mounted pedestal for engaging the underside of each of the other arms of the platform 60. By bringing all the pedestals into engagement with the platform 60, the pitch

soft cylinders

140, 142, 144, and 146 can hold the platform 60 in fixed position about the pitch axis relative to the gimbal frame 58. By backing off the pedestals, the angular motion of the platform 60 relative to the gimbal frame 58 can be limited to any desired angle within the normal limits of angular movement of the platform.

To provide a positive locking arrangement between the platform 60 and gimbal frame 58, four hydraulically operated

pitch locking units

152, 154, 156, and 158 are provided adjacent the corners of the gimbal frame 58. Each locking unit includes a hydraulic actuator 160 which moves a locking pin 162, slidably mounted in a housing 164 of the locking unit 152, between two positions. The housing 164 is mounted on the gimbal frame 58 by means of the

brackets

134 and 136. The pin 162 when extended in the locking position engages a stop member 166 secured to the adjacent leg 72 of the derrick. Similarly the other three locking

units

154, 156, and 158 actuate detent pins which are movable into engagement with stop members secured to the other three legs of the derrick adjacent the platform 60. Thus the platform 60 can be locked to the gimbal frame 58 to prevent angular movement of the platform about the pitch axis relative to the vessel.

What is claimed is:

1. In a deep ocean mining vessel or the like, a gimbal system to provide a stable base for a derrick, comprising a pair of spaced vertical guide frames mounted on the vessel, a pair of gimbal support members movable vertically on the respective guide frames, heave control means controlling the position and movement of the gimbal support members relative to the guide frames, a gimbal frame, means rotatably supporting the gimbal frame on the gimbal support members for rotation about a first axis of rotation, a platform, means rotatably supporting the platform on the gimbal frame for rotation about a second axis of rotation substantially perpendicular to the first axis of rotation, means for controlling the rotation of the platform about the second axis including a plurality of hydraulic linear actuator means, a plurality of variable length snubbing members mounted on the gimbal frame, the snubbing members when extended engaging the platform at widely spaced points on either side of the second axis, the snubbing members being variable in length in a direction substantially parallel to the direction of movement of the platform relative to the snubbing members,

whereby changing the length of the snubbers controls the limits of rotational movement of the platform about the second axis.

2. Apparatus of claim 1 further comprising means for controlling rotation of the platform and gimbal frame about the first axis including a second plurality of variable length snubbing members, means mounting the second plurality of snubbing members in fixed relation to the vessel, the snubbing members being variable in length, the platform including means engaging the snubber means when rotated in either direction about said first axis.

3. Apparatus of claim 2 further including releasable locking means mounted on the gimbal frame and the guide frames for locking the gimbal frame to the guide frames to prevent vertical heave and rotation of the platform about said first axis.

4. Apparatus of claim 1 further including releasable locking means mounted on the gimbal frame and the platform for locking the platform to the gimbal frame to prevent relative rotation about said second axis.

5. A gimbal system for providing a stable work platform on a floating vessel, comprising: an open gimbal frame, means-rotatably supporting the gimbal frame from the vessel for rotation of the gimbal about a first axis, means rotatably supporting the platform within the gimbal frame for rotation about a second axis, first adjustable length snubbing means mounted on the gimbal frameon either side of the second axis, the snubbing means including movable stop members and means for moving the stop members in a direction tangent to a circle centered on the second axis, the stop members being positioned to engage the platform and limit rotation of the platform about the second axis, second adjustable length snubbing means mounted on the vessel, the second sn ubbing means including opposin'g movable stop members and means for moving the stop members toward and away from each other, the platform including means integral therewith extending between the opposing stop members, said last named means moving into engagement with the stop members on rotation of the gimbal frame about said first axis.

6. Apparatus of claim 5 further including releasable locking means mounted on the gimbal frame and the platform for locking the platform to the gimbal frame to prevent relative rotation about said second axis.

7. Apparatus of claim 5 further including releasable locking means mounted on the gimbal frame for locking the gimbal frame to guide frames to prevent rotation of the platform about said first axis.

8. Apparatus-of claim 5 further including releasable locking means mounted on the gimbal frame and the platform for locking the platform to the gimbal frame to prevent relative rotation about said second axis, and further including releasable locking means mounted on the gimbal frame for locking the gimbal frame to guide frames to prevnt rotation of the platform about said first axis.

Claims

1. In a deep ocean mining vessel or the like, a gimbal system to provide a stable base for a derrick, comprising a pair of spaced vertical guide frames mounted on the vessel, a pair of gimbal support members movable vertically on the respective guide frames, heave control means controlling the position and movement of the gimbal support members relative to the guide frames, a gimbal frame, means rotatably supporting the gimbal frame on the gimbal support members for rotation about a first axis of rotation, a platform, means rotatably supporting the platform on the gimbal frame for rotation about a second axis of rotation substantially perpendicular to the first axis of rotation, means for controlling the rotation of the platform about the second axis including a plurality of hydraulic linear actuator means, a plurality of variable length snubbing members mounted on the gimbal frame, the snubbing members when extended engaging the platform at widely spaced points on either side of the second axis, the snubbing members being variable in length in a direction substantially parallel to the direction of movement of the platform relative to the snubbing members, whereby changing the length of the snubbers controls the limits of rotational movement of the platform about the second axis.

5. A gimbal system for providing a stable work platform on a floating vessel, comprising: an open gimbal frame, means rotatably supporting the gimbal frame from the vessel for rotation of the gimbal about a first axis, means rotatably supporting the platform within the gimbal frame for rotation about a second axis, first adjustable length snubbing Means mounted on the gimbal frame on either side of the second axis, the snubbing means including movable stop members and means for moving the stop members in a direction tangent to a circle centered on the second axis, the stop members being positioned to engage the platform and limit rotation of the platform about the second axis, second adjustable length snubbing means mounted on the vessel, the second snubbing means including opposing movable stop members and means for moving the stop members toward and away from each other, the platform including means integral therewith extending between the opposing stop members, said last named means moving into engagement with the stop members on rotation of the gimbal frame about said first axis.

8. Apparatus of claim 5 further including releasable locking means mounted on the gimbal frame and the platform for locking the platform to the gimbal frame to prevent relative rotation about said second axis, and further including releasable locking means mounted on the gimbal frame for locking the gimbal frame to guide frames to prevnt rotation of the platform about said first axis.