Marine tether anchoring device

Abstract

A releasable marine tether connection comprises a tether having a segmented spring collet which can be expanded to become trapped in an anchor chamber. A spigot is provided in the base of the chamber which urges the plug upwards relative to the collet when the tether is pushed into the chamber to make the connection. To release the connection tension is removed from the tether and the plug moved down to allow the spring collet to close and move out of the chamber.

We claim: 
     
       1. A marine tether anchoring device for use with an anchoring chamber having a neck portion, comprising a tether provided with a hollow segmented first spring collet adapted to be inserted into the neck portion of said chamber, said first collet having adjacent its extreme end an inner enlarged cavity, an intermediate section of diminishing width between said cavity and a hollow passage through said first collet, a locking plug extending along said hollow passage and having an end of increased width arranged to be located in said enlarged cavity in a first position, and means for moving said plug between said first position and a second position when said plug engages the intermediate section to open out said first collet and provide a securing of said first collet in the anchoring chamber, said anchoring device further comprising a first slideable sleeve in the neck portion of the anchoring chamber, said first sleeve having a second spring collet, provided with a load ring at its lower end, and which can be expanded to be securely engaged in an uppermost position in said anchoring chamber when tension is applied to the tether, and a second slideable sleeve within said first sleeve and surrounding said hollow segmented first spring collet, said second sleeve extending to a locking ring arranged to engage between said load ring and outer parts of said intermediate section, in which said load ring can be forced outwards to release said locking ring when said first slideable sleeve is in a lowermost position. 
     
     
       2. A marine tether anchoring device according to claim 1, in which said means for moving said plug between said first and second positions comprises a spigot, said second sleeve extending beyond said locking ring to support and locate said spigot so that it is arranged to move the locking plug from said first position to said second position when the anchoring device is pressed towards the bottom of the anchoring chamber. .Iadd. 
     
     
       3.  A marine tether anchoring device comprising: (a) an anchoring chamber for fixing to the seabed;   (b) means defining a mouth of said anchoring chamber;   (c) a hollow segmented collet for attachment to the lower end of said marine tether that can take up a retracted state in which it can pass through said mouth into said anchoring chamber and which can take up an expanded state in which it cannot pass through the mouth of the anchoring chamber and is retained captive therein;   (d) means defining a passage through said collet;   (e) a plug in said passage arranged for sliding axial movement relative to said collet between an inoperative position and a working position;   (f) means defining a tapered face of said plug that cooperates with portions of said passage to expand said collet as said plug moves from its inoperative to its working position;   (g) a protuberant member in the anchoring chamber arranged to move the plug to its working position as the collet travels fully into the anchoring chamber; and   (h) latch means on the inner faces of the segments of said collet that closes behind said plug as it is moved into its working position to hold said plug in its working position..Iaddend. .Iadd.   
     
     
       4.  The anchoring device of claim 3, wherein said collet has resiliently flexible segments that snap engage said latch means with said plug..Iaddend. .Iadd.5. The anchoring device of claim 4, wherein said collet is formed at its end with a cavity into which said plug fits when in its inoperative position..Iaddend. .Iadd.6. The anchoring device of claim 5, wherein the free end of said cavity is formed with an inwardly projecting flange that prevents removal of said plug..Iaddend. .Iadd.7. An anchoring device according to claim 3, further comprising hydraulic or pneumatic means operable to return said plug from its working to its inoperative position..Iaddend. .Iadd.8. An anchoring device according to claim 3, wherein said anchoring chamber comprises a chamber portion, a neck portion smaller than said anchoring chamber and a frustoconical bearing surface between said chamber portion and said neck portion and the outer surface of said collet segments have protuberant frustoconical portions adapted to abut against said bearing surface when said collet segments are expanded. .Iaddend.