Improvements Relating To Release Mechanism For Buoys

Abstract

A buoy comprising a sinker, a sub-surface float and a surface float is dropped into the water as a single unit. The sinker is released by means which are not described, the invention being concerned with the means for securing and releasing the surface float. Four longerons are rigidly secured to the sub-surface float and have openings near their free ends. Attached to the surface float are four brackets each carrying a pivotable member whose ends are located in the openings of a respective longeron. The pivotable members are secured by a wire which passes around the surface float and engages each of the pivotable members, the ends of the wire being joined together by a timed release mechanism which after a predetermined time releases the ends of the wire and thus releases all the pivotable members simultaneously.

Description

The present invention relates to release mechanisms, for buoys especially those used in oceanographic buoy systems.

The complexity and size of present day oceanographic buoy systems makes it desirable to launch the system as a package and cause it to divide and moor automatically. An example of such a system is a two stage taut wire mooring. This usually comprises three assemblies: an anchor, a sub-surface float, and a surface buoy. These three assemblies, after implantation, are located respectively on the sea floor; in a mid-water position; and on the surface. A successful automatic implanation of such a system depends basically on a timed sequence of events after launching the package comprised of the three assemblies. This involves for the system considered two timed releases, one to separate the anchor, and the other to separate the surface buoy from the sub-surface float.

In the case of the last mentioned release there exists the risk of jamming as the buoy rises from the sub-surface float, deploying a tethering cable as it rises; and moreover the risk that the buoy might not start its rise vertically, so deploying more tethering cable than is necessary, and increasing the risk of jamming.

It is an object of the present invention to provide a release mechanism for a buoy in which one or more of the above mentioned risks are substantially reduced.

According to the present invention there is provided a mechanism for attaching a buoy to and for realeasing it from a body including a plurality of members projecting from said body, each of said members having a guide part, a plurality of pivotable connecting means attached to said buoy each for connection to a respective one of said members, means for constraining said connecting means to maintain attachment between said buoy and said body and for releasing simultaneously all said connecting means, each said connecting means having a part adapted to co-operate with said guide part of a respective one of said members to guide the initial movement of said buoy relative to said body upon the release of said connecting means.

In order that the present invention may be fully understood and readily carried into effect it will now be described with reference to the accompanying drawing, in which:

FIG. 1 shows a perspective view of part of a package for an oceanographic buoy system including one example of a release mechanism according to the present invention, and

FIGS. 2, 3 and 4 are diagrams showing various stages in the operation of the release mechanism.

The example according to the present invention to be described is one for releasing a surface buoy from a subsurface float either at a predetermined depth or a given time after implantation.

Referring first to FIG. 1, a surface buoy 2 is attached to a sub-surface float 8 by means of four longerons 1, providing four initial holding points for the surface buoy. Correct location of the surface buoy 2 is obtained by outwardly projecting arms formed with downward facing cones, and shown by reference 3, the cones being mounted in respective seats in the top of the longerons 1. To maintain this location holding forces are supplied by respective ones of four hook ended levers 4 which are pivotted on abutments 11 on the surface buoy 2, and engage in respective ones of longitudinal slots 9 formed in the longerons 1. Each one of levers 4 straddles a respective one of walls 5 which separate slots 9 from second slots 10. The lower end of each lever 4 is shaped into a right angle with an upstanding bearing cone which bears against the underside of the respective wall 5, providing the holding force. The levers 4 are constrained to this holding position by means of a single release wire 6, under tension, and passing through each lever 4 around the buoy 2. This holds the levers 4 in their correct positions which is shown in more detail in FIG. 2, reference 7 denoting a junction mechanism in which each end of wire 6 is connected for maintaining the tension. On release of the tension in wire 6 by mechanism 7 (which may comprise either means responsive to sea pressure or timing means such as a corrosion link soluble in water, for parting the connection of cable 6 in mechanism 7), the buoy 2 is free to move out of engagement with the longerons 1. However by virtue of the disposition of the hook portions of levers 4 in slots 9, and the displacement of the levers round the buoy, tilting and jamming are substantially eliminated by the hook portions of levers 4 turning over about their pivots and maintaining their engagement in the slots 9 during initial movement of the buoy. This is shown in FIG. 3.

At the point where the buoy becomes sufficiently clear of the longerons 1, and there is no possibility of jamming it is arranged that the hook portions at this point have turned out of the slots 9, and disengagement of the buoy from the package is completed. The onset of this is shown in FIG. 4.

Although the invention has been described with reference to the one embodiment, it will be clear to those skilled in the art that other embodiments are possible within the scope of the invention.

Claims

What I claim is:

1. A mechanism for attaching a buoy to and for releasing it from a body including a plurality of members projecting from said body, each of said members having a guide part, a plurality of pivotable connecting means attached to said buoy for connection to a respective one of said members, a tensioned cable for constraining said connecting means to maintain attachment between said buoy and said body, said tensioned cable operating to constrain each of said connecting means to engage a respective one of said members, and means for releasing the tension in said cable thereby to release simultaneously all said connecting means, each said connecting means having a part adapted to co-operate with said guide part of a respective one of said members to guide the initial movement of said buoy relative to said body upon the release of said connecting means.