GB2463644A

GB2463644A - Anchor with tidal flow enhanced engagement means

Info

Publication number: GB2463644A
Application number: GB0816987A
Authority: GB
Inventors: William Kingston
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-09-17
Filing date: 2008-09-17
Publication date: 2010-03-24
Also published as: GB0816987D0

Abstract

Two mating parts form an anchor for equipment which needs to be removed at intervals from the sea bed. One part 2 is permanently fixed, and the other 1 is kept in contact with it by a hydrofoil 5 which produces a downward force from the tidal flow past the anchor. Additionally, both parts can be positively locked together when the tide is flowing. The parts may be locked together by locking means (14, Fig 3) actuated by reciprocating movement of a component (7, Fig 3), or by pressure from the hydrofoil. The locking means may also be actuated by remote or timer control of a source of power incorporated in one of the anchor components.

Description

Tideway anchor The lateral force of tidal flow on objects positioned on the sea bed is considerable, and may require expensive works to counter it. The concept of using the force of the tidal stream itself instead of these was first disclosed in my patent No. GB 1131856.

More recently, it has been developed further, see US patent No. 7275891 to Owen.

All this prior art used hydrofoils of symmetrical section. The following improvement, which enables foils of non-symmetrical section to be used, is particularly designed to operate in conjunction with my tidal turbine invention, disclosed in W02007086037.

In the accompanying drawings, Fig. 1 is a plan view of the invention, Fig. 2 is a side section of it, and Fig. 3 is a section of an arrangement for locking the two parts of the anchor positively together when the tide is acting to pull them apart, but unlocking them around the tidal null point, so that whatever gear is being held by the anchor can be easily retrieved when required, at such times. It is essential that any such locking arrangement be completely reliable in operation, since otherwise either the gear would be swept away by the tide, or it would be impossible to retrieve it from the sea bed for maintenance at times when the tidal current is not flowing. This invention uses the completely reliable forces of the tide itself for both locking and unlocking the separate parts of the anchor.

in all three figures, 1 is a support for equipment to be moored in a tidal stream by being inserted into a socket 2 in the sea bed. In figures 1 and 2, reference 3 is a supporting collar around the circumference of support 1, and 4 is a bearing which also fits over support 1 and runs on collar 3. 5 is a hydrofoil of non-symmetrical section designed to generate inverse lift,' attached to bearing 4, and 6 is a vertical tailplane, on which the force of the tidal stream acts to rotate bearing 4 with its attached hydrofoil 5 so that the hydrofoil's leading edge faces the tidal stream.

In Figure 3, 7 is a shaft which pivots on axle 8, journalled in trunnion 9 attached to the top of support 1, so that it can move in an arc in the plane of the tidal stream and under the force of that stream. Such a shaft, for example, could be the drive shaft shown in my tidal turbine invention or an extension of it. 10, 10 are a pair of master hydraulic cylinders, whose piston rods are attached to and movable by the lower end of shaft 7. Master cylinders 10, 10, are connected by hoses 11, 11 to a pair of slave hydraulic cylinders, 12, 12, which are rigidly fixed to the inside wall of support 1.

Hoses 11 are connected to different ends of master cylinders 10, 10, so that movement of shaft 7 about axle 8 produces the same direction of movement of hydraulic fluid through each hose. 13, 13 are rollers on the end of the piston rods of slave cylinders 12, 12; and 14, 14 are a pair of locking bars which are shaped to slide in slots 15, 15, cut in the walls of support 1, and also in slots 16, 16, cut in the walls of socket 2. 17, 17 are slots in locking bars 14 along which rollers 13, 13 can move to cause lateral movement of these bars. The necessary reservoir for hydraulic fluid is not shown.

In operation of the version of the invention which does not have the locking mechanism, support 1, together with whatever is attached to it, is placed in its socket on the sea bed during a tidal change period, when there is little or no water movement.

When the tide begins to flow, it acts upon tailpiane 6 to turn the hydrofoil 5 to face the current. As the current flow increases, hydrofoil 5 generates a downwards force which acts on support 1 through bearing 4 and collar 3. This force counteracts the tendency of the vertical component of the tidal force, in its action on equipment attached to the top of support 1, to pull support 1 out of socket 2. As a result, socket 2 need not be as deep nor as strongly constructed as it would have to be without hydrofoil anchoring.

This reduction in the depth of socket 2 can be even greater if the two mating components are positively locked together while the tidal force is acting to pull them apart. In this version of the invention, at the tidal null point there is no lateral force on shaft 7, so that it takes up a vertical position. When the tide flows, it will bring whatever is attached to the part of shaft 7 that is above axle 8 (such as a tidal turbine) with it. This will cause the part of the shaft below axle 8 to move in the opposite direction, so that the pistons in master hydraulic cylinders 10 are moved to force fluid through hoses 11 into slave cylinders 12. The pressure from this forces the piston rods in slave cylinders 12 downwards. Because rollers 13 are on the end of this rod and also run in slots 17, and because the slave cylinders cannot move, downwards movement of roller 13 forces bars 14 laterally into slots 16 in the wall of socket 2.

Bars 14 cannot move from there as long as the tide is running, so that support 1 and socket 2 are positively locked together throughout this period. This makes it quite impossible for the vertical component of the tidal force on anything being held by the anchor to pull support 1 out of socket 2, up to the limit of their constructional strength.

At the tidal null point, the return of shaft 7 to the vertical position reverses the movement of hydraulic fluid. This withdraws the piston rod of each slave cylinder into that cylinder, which causes the resulting movement of roller 12 to withdraw bar 13 from slot 14 in socket 2. Support 1, with any gear attached to it, can then be freely withdrawn from socket 2. Starting of the tidal flow in the reverse direction, repeats the locking cycle.

The hydrofoil arrangement in Figures 1 and 2 can be combined with the locking arrangement of Fig. 3. An effective way of doing this is to make the hydrofoil and its associated gear marginally buoyant but with its capacity to move vertically limited to the length of travel of a piston in a master cylinder 10. This cylinder can then be attached under the hydrofoil arrangement in such a way that the latter's vertical movement actuates it. Consequently, when the tidal flow presses hydrofoil 5 downwards, it has the same effect as the movement of shaft 7 in locking both mating components positively together. Around the tidal null point, this pressure on the hydrofoil ceases, so it is free to move upwards under its slight positive buoyancy within the limit set for it. This movement reverses the flow of fluid between the two cylinders to unlock the mating components.

There are several other ways of putting the invention into effect within the scope of the invention. The locking system could be operated from a power source such as an electrical battery, incorporated in support 1, and actuated by a remote signal. Also, because future tidal movements can be predicted with great accuracy, actuation of the power could be timer-controlled.

Claims

Claims: 1. An anchor for gear in a tideway, characterised by a pair of mating components, one of which is fixed to the sea bed, and the other of which is removable and adapted for whatever is to be anchored, to be attached to it, the removable component having pivotally attached to it in a substantially horizontal plane, a hydrofoil of non-symmetrical section capable of generating downwards force on it from the tidal flow, and means attached to the hydrofoil for turning it to face into the tidal flow.
2. An anchor for gear in a tideway, characterised by a pair of mating components, one of which is fixed to the sea bed, the other being removable and adapted for whatever is to be anchored, to be attached to it, and means for locking both components positively together during the period of tidal flow and unlocking them during the tidal change period.
3. An anchor as in Claim 2, in which the locking means is actuated by reciprocating movement of a component, caused by the tidal stream.
4. An anchor as in Claim 2, in which the locking means is actuated by pressure from a hydrofoil.
5. An anchor as in Claim 2, in which the locking means is actuated by a remote signal to a source of power incorporated in one of the anchor components.
6. An anchor as in Claim 2, in which the locking means is actuated by timer control of a source of power incorporated in one of the anchor components.