Abstract:
A pin connection for remote releasably locking two sides of a connection together comprising multiple fingerlike projections from two opposing sides of the connection which contain locking pins of a length approximately equal to the width of the fingerlike projections and mounted in holes in the fingerlike projections, the locking pins being centrally located in the holes in the unlocked position and being across the interfaces between the fingerlike projections when locked.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to assemblies which wrap around circular pipes and similar devices which require that the abutting ends be pinned together such that the pins will be in shear and will be benefited by multiple shear planes to carry the shear loads. 
     2. Description of the Related Art 
     Pipe support assemblies frequently referred to as slip assemblies are frequently hinged so that they can be engaged around pipe while it is supported from the top. The slips are segmented units which have sharp teeth in the inner surface to grab the pipe with a high friction coefficient and are characteristically tapered on the back (8° to 15° with respect to the centerline) so that they will be wedged against the pipeline. The slip segments fit within a bowl which has a corresponding inner taper. The bowls will be segmented in 2 to 4 pieces to allow the hinging around the pipe. The interface between the sections will normally remained pinned to allow flexibility, except for one interface. That interface will have alternating finger like projections from the edges of each of the slip bowl sections that mesh together when they are brought to adjacent positions. 
     On the edge of a bowl section, each of the fingerlike projections will have a hole, with the holes being on a common centerline. When the edges of two bowl sections are brought together and the fingerlike projections mesh, the holes on one edge will be aligned with the holes on the other section and allow a pin to be inserted into the aligned holes. 
     When the slip segments are loaded with a pipe section and cause an outward force due to the taper on the slip segments and bowl, the outward force is translated into a circumferential or hoop force in the bowl, causing a shear stress in the pin. The force is divided by the number of times the pin is put in shear in the construction. 
     In conditions involving larger pipe sizes and high loads, the diameter and length of the pin can cause the pin to be long and heavy. Large and long pin sizes promote the need for automation of operation of the insertion and removal of the pin. The need for remote operation of the pin such as in the mast of a rig or on the seafloor also promote the need for remote operation. The longer the pin, the longer the operating cylinder. Long cylinders complicate the design and add to system space considerations. 
     The present invention is directed to overcoming, or at least reducing the effects of one or more of the problems set forth above. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to provide a pin connection which can be remotely operated. 
     A second object of this invention is to provide for remote or power operation of the pin, with a reduced space requirement. 
     A third object of this invention is to provide means for accurately aligning the ends of the pipelines for welding and laying. 
     Another object of this invention is to provide a pin connection which is failsafe to the closed or locked position. 
    
    
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon referring to the drawings which follow. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a half section thru a preferred embodiment of the pin connection in the locked position. 
     FIG. 2 shows a half section thru the pin connection in the unlocked position. 
     FIG. 3 shows a half section of the pin connection in the unlocked position with the bowl sections separated. 
     FIG. 4 shows a half section of a subsea clamp assembly which is designed to be engaged around a pipeline and then locked together. 
     FIG. 5 shows an end view of the clamp of FIG. 4 being open and lowered onto a subsea pipeline. 
     FIG. 6 shows the clamp of FIGS. 4 and 5 being engaged with the pipeline and locked in place. 
     FIG. 7 shows an isometric view of a J-Lay Tower which has a travelling table with a clamp mechanism amenable to remote control. 
     FIG. 8 shows a top view of the clamp assembly with the doors closed around a pipe section. 
     FIG. 9 is a top view of a clamp assembly of FIG. 8 in the traveling table of FIG. 7 with an open clamp. 
     FIG. 10 shows the front view of the clamp assembly of FIG. 9 with the doors closed around the pipe section. 
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort, even if complex and time-consuming, would be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     Referring now to FIG. 1, pin connection  10  includes first bowl section  12  and second bowl section  14 . Bowl section  12  has fingerlike projections  16 ,  18 , and  20 . Bowl section  14  has fingerlike projections  22 ,  24 , and  26 . A multiplicity of pin sections  28  extend thru holes  30  in the fingerlike projections. 
     Each pin section  28  has a slot  32  with a detent hole  34  in each end of the slot. A stop pin  36  is engaged in the detent hole  34  in one end of slot  32  and is urged into the hole by spring  38 . In this manner, when a stop pin is engaged into a detent hole, the pin section tends to remain in place. Alternately, variations such as a simple circular detent groove can be used to both detent and stop the locking pin. 
     A release cylinder  40  includes a cylinder  42 , a cap  44  with a threaded connection port  46 , and a piston  48 . When the release cylinder is pressured thru the port  46 , the pin sections are moved from straddling the interfaces between the fingerlike projections to being between the interfaces. 
     A locking cylinder  50  includes a cylinder  52 , a cap  54  with a threaded connection port  56 , a piston  58 , a piston extension  60 , a cap extension  62 , and a series of conical springs  64 . 
     In this view, each of the five pin sections will be loaded in shear about their central sections if the two bowl sections are attempted to be pulled apart. 
     Referring now to FIG. 2, port  46  has been pressured and the fluid has been vented out port  56 . Piston  48  has moved down, pushing all the pin sections  28  from their upper detented positions to their lower detented positions. Port  66  has also been pressured to move the piston  58  down until piston extension  60  contacts the cap extension  62 . The pin connection is now unlocked. 
     Referring now to FIG. 3, pin connection  10  is released as bowl section  12  is displaced away from bowl section  14 . 
     Referring now to FIG. 4, clamp assembly  70  surrounds a subsea pipeline  72  and has slip segments  74 . The slip segments have sharp teeth that engage the pipeline for pulling the pipeline in operations such as recovery of the pipeline to the surface. Slip bowl segments  76  surrounds the slip segments  74  and provides a tapered interface  78  between the two. Pin connection  80  provides for the releasable connection between two adjacent bowl sections. Rollers  82  provide for guiding the clamp assembly on the pipeline until the slip segments are set onto the pipeline. 
     Referring now to FIG. 5, cylinders  90  hold the bowl segments  76  in an open position to land over the pipeline  72 , keeping the sections  92  and  94  of the connection  80  separated. 
     Referring now to FIG. 6, the cylinders  90  have been extended to bring the sections  92  and  94  together to allow the pin connection  80  to be locked together. Padeyes  96  are provided for attachment of cables to pull the clamp assembly and therefore the pipeline. 
     Referring now to FIG. 7, a perspective view of a J-Lay pipeline tower  100  which is benefited by the application of the present invention. Base skid  102  is provided with extensions  104  to each side. A gimbaling stationary table  106  is supported on three adjustable jacks  108 . Mast sections  110 ,  112 , and  114  are supported off the stationary table  106 . The upper portion  116  of the pipeline being supported on bushing  118  on the stationary table  106 . 
     New pipe sections to be welded into the pipeline being laid by the system are brought up from the deck of the lay vessel by the erector  120  and engaged by the travelling table  124 . The travelling table  124  is lifted by a pair of cylinders  122  with cables  126  over drums  128 . The remote and moveable location of the travelling table  124  makes it beneficial to have connections in the travelling table operated by remote control. 
     Referring now to FIG. 8, travelling table  124  is shown with holes  140  on each side for attaching the cables  126 . A main clamp segment  142  is provided with cylinders  144  to move the main clamp segment toward or away from the pipeline. Clamp segments  146  and  148  wrap around the pipeline  116  and are connected with pin connection  150 . Cylinders  152  and  154  are provided to open and close the clamp segments  146  and  148  when the pin connection  150  is unlocked. 
     Referring now to FIG. 9, the pin connection  150  is unlocked and the clamp segments  146  and  148  are opened. 
     Referring now to FIG. 10, a front view of the traveling table is provided showing the clamp segments  142 ,  146 , and  148  along with the pin connection  150 . 
     The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.