WO2020079385A1

WO2020079385A1 - Recovery apparatus for retrieving ferromagnetic objects from bodies of water

Info

Publication number: WO2020079385A1
Application number: PCT/GB2019/000144
Authority: WO
Inventors: Alistair John GRIFFITHS
Original assignee: The Secretary Of State For Defence
Priority date: 2018-10-18
Filing date: 2019-10-07
Publication date: 2020-04-23
Also published as: GB2578964B; GB2578964A; GB201816962D0; GB201914573D0

Abstract

The present invention is concerned with improved apparatus and methods for retrieving ferromagnetic objects from bodies of water.

Description

Recovery Apparatus for Retrieving Ferromagnetic Objects from Bodies of Water

The present invention is concerned with apparatus for retrieving ferromagnetic objects from bodies of water.

Magnetic fishing is a well-known phenomenon, whereby a magnet, quite possibly a very strong magnet, attached to a rope of tether can be plunged into a body of water to retrieve ferromagnetic objects that are present in that body of water. The approach is used by hobbyists, such as persons interested a metal detecting, but can also be used to retrieve objects which may have accidentally been dropped into the body of water, or even objects which may have been purposefully dropped into the water, such as a weapon which may have been used in a crime. Clearly, a magnet attached to ja ope or tether may also be used to retrieve objects from other environments, especially environments or situations where the object cannot be reached easily.

Ferromagnetic objects are objects made from or comprising materials that can be magnetised, and/or are materials that are attracted to a magnet. Such materials are known as ferromagnetic, or ferrimagnetic, and include iron, nickel, cobalt, and some alloys of rare-earth metals. Retrieval of objects relating to a potential crime is usually undertaken through location of suspect objects, for example using sonar technology, with retrieval often undertaken by divers. Flowever, this clearly requires a diver or diver team to be available, which is also an expensive and often scarce resource to be reliant upon. It would be beneficial if alternative means for retrieving the objects could be developed, to avoid use of divers or diving teams. It would also be advantageous if the retrieval means could be selective, and quick and simple to use, to ensure the desired object is retrieved.

The majority of magnetic fishing apparatus tend to be indiscriminate in the objects that they will attach to, which could potentially be an issue where a person is in particular looking for or wishing to retrieve a particular object. In particular, magnetic fishing apparatus, especially those using particularly strong magnets to retrieve objects, may attach to large, heavy and/or bulky objects which are difficult to physically retrieve from a body of water, but at the same time it may be difficult to detach the magnetic apparatus from the object, with in the worst case scenario the magnetic apparatus itself not being able to be retrieved, since it cannot be detached, with the attached rope/tether potentially creating a hazard, such as to animals or vessels.

Thus there is a requirement for improved magnetic fishing apparatus or recovery apparatus which are capable of being selective as to which objects can or are to be retrieved, and/or apparatus which can be more easily detached from such objects, especially large, heavy and /or bulky objects.

The present invention thus generally aims to provide improved recovery apparatus for retrieving ferromagnetic objects, and especially retrieving such objects from bodies of water, such as rivers, lakes, wells, or oceans.

Thus, in a first aspect the present invention provides a recovery apparatus for retrieving ferromagnetic objects from bodies of water comprising a magnet attached to a tether wherein the magnet is housed or encased within a non-magnetic housing and the magnet is further capable of being moved within the housing, from a first position to a second position, to enable the magnet to be distanced from the retrieved object and thereby the retrieved object to be detached from the apparatus.

The ability to move the magnet within the housing from a first position (at its closest position to the object to be retrieved), most likely adjacent to the base of the apparatus (which in use would be a part of the apparatus designed or arranged to contact with the object) to a second position (at its furthest position from the object to be retrieved), enables the magnet to be distanced/separated from the retrieved object, thereby reducing the strength/magnitude of the magnetic

force/attraction between the object and the magnet, so that the object can be detached, or be more easily detached, from the apparatus/magnet. The apparatus may be capable of allowing the object to be automatically detached, on movement of the magnet from the first position to the second position, or may require the apparatus to be pulled from the object, which could be through use of the tether or a rope. The magnet is preferably capable of being moved from the first position to the second position in response to an action by a user of the apparatus, which could be application of a force to the apparatus and/or magnet in order to move the magnet from the first position to the second position, although this could alternatively be achieved using automated or electronic means for example. The apparatus thus comprises means suitable for allowing the magnet to be moved from the first position to the second position. This could for example be achieved through use/application of the tether, or possibly a further (second) tether, which could for example be controlled from a user at the surface of the body of water, such as in a boat or on the bank of the body of water. The user could thus advantageously detach the object whilst the apparatus is in situ within the body of water, and whilst the housing remains immersed. The tether or second tether may be a rope, or similar means. In one embodiment, the apparatus comprises a pulley system to enable the magnet to be moved from the first position to the second position, which could be achieved by or be in response to a force being applied to the pulley system by a user of the apparatus, most likely through use of the tether or second tether, which may be a rope. By incorporating such a pulley system into the apparatus, the force to move the magnet from the first position to the second position would be appreciably less than the force that would be required in an apparatus without a pulley system. Application of the force could for example be achieved by means of the tether, or possibly a further (second) tether, which may be a rope or similar means, as mentioned previously. A pulley system is a system comprising at least one, but preferably more than one, pulley designed to work in combination with a tether or rope, or similar means such as a belt, or chain. Pulley systems are generally used to provide a mechanical advantage, and are commonly used for hauling and lifting loads, especially heavy loads. Preferably the apparatus further comprises means to automatically return the magnet to the first position, for example upon removal of the action or force from the user. The magnet in the apparatus may for example be biased to being at the first position, for example when a force is not being applied by a user (to move the magnet to the second position) the magnet would

preferentially be at, or be returned to, the first position. This may for example be provided by the apparatus comprising spring loaded means. In one embodiment, the apparatus comprises spring loaded means biased to the magnet being held at the first position, or preferentially to retain the magnet at the first position, or to return the magnet to the first position, for example upon removal of a force applied by a user, such as may have been applied to the pulley system. Spring loaded means/systems are used in the art for holding a component (preferentially) in/at a particular position, thus in the system the spring loaded means holds the magnet preferentially at the first position.

The first position within the apparatus is preferably at a predefined distance from/above the base of the apparatus, to protect the magnet and/or ensure that most objects captured by the apparatus do not attach directly to the magnet, which also contributes to protecting the magnet. The predefined distance may be between about 2 and 20 mm, and in one embodiment is between 3 and 5 mm. The second position within the apparatus is preferably at a predefined distance from/above the base and at a predefined distance from/above the first position, to enable the magnet to be moved to a position further away from any object attached at the base of the apparatus, to reduce the strength/magnitude of the magnetic force/attraction between the object and the magnet, and thereby allow the object to be detached from the apparatus. The predefined distance between the first position and the second position may be any suitable distance to achieve the effect, and could be between 10 mm and 300 mm.

The tether may comprise a rope and/or a pole, to enable the housing/magnet to be lowered into the body of water by a user, and/or to enable the magnet to be moved from the first position to the second position by a user. The pole could be a collapsible pole, or a detachable pole. In one embodiment the tether comprises a pole, and the means for moving the magnet from the first position to the second position is a rope (which could also be referred to as a second tether), which rope could for example be located within the pole (which feature could not only provide protection for the rope, but also mitigate the chance of the rope becoming trapped or caught, especially when being pulled (i.e. when a force is being applied to the rope by a user) to move the magnet from the first position to the second position.

The non-magnetic housing may be waterproof or water resistant, or at least comprise a waterproof or water resistant feature to provide better protection of the magnet and/or the means for moving the magnet from the first position to the second position, such as the pulley system, from the environment. The water proof or water resistant feature could for example mitigate the pulley system being corroded. The water proof feature could comprise plastic, such as a plastic sheet around the pulley system.

The apparatus of the first aspect is capable of recovering or retrieving desired objects, whilst reducing or even eradicating the chance of the apparatus becoming unrecoverable as a result of attaching to large, heavy, and/or bulky objects. The apparatus may further comprise a camera or similar means to view the area adjacent the apparatus, and in a preferred embodiment to view the object that the apparatus has attached to, for example to decide whether the object should be detached or retrieved, which could thus in particular enable the user to target a desired object, providing the apparatus with a further increase in selectivity. The camera or similar means could be linked through a wireless link to a mobile phone app to be able to aid the search or retrieval. The apparatus may comprise light attachments to aid viewing the area adjacent the apparatus underwater. The light attachments may comprise LEDs.

The magnet is preferably a strong or high-performance magnet, for example one comprising or consisting of a rare earth metal, such as neodymium. The non-magnetic housing may comprise or be made from a plastic, for example acrylic. In one embodiment the magnet itself within the housing may be further encased in a non-magnetic material, to provide further protection to the magnet from any object which may attach to the apparatus, or directly to the magnet. In a second aspect, the present invention provides for use of a pulley system in magnetic recovery apparatus.

In a third aspect, the present invention provides for use of spring loaded means in magnetic recovery apparatus.

In a fourth aspect, the present invention provides for use of the apparatus of the first aspect for magnetic fishing.

In a fifth aspect, the present invention provides for use of tie apparatus of the first aspect in law enforcement, in particular to retrieve objects related to a c'ime from a body of water, and in particular to supplant or mitigate the need for a diver or dive team to be used for the retrieval.

The present invention shall now be discussed with reference to the following non-limiting example and figure in which

Figure 1 is a section illustration of an apparatus of one embodiment of the first aspect.

Example

Having regard to figure 1, one embodiment of a recovery apparatus 1 comprises a housing 2, made from a non-magnetic material, which has a base section 3. Within the housing is magnet 4, which is encased in a non-magnetic material. The apparatus comprises a spring loaded system 5 biased to hold or return the magnet 4 always to the same position (first position), just above the base plate. The apparatus also comprises a pulley system 6 to enable the magnet 4 to be moved away from the base section 3 (to a second position) in response to a force, which in this case would be a force applied by a user pulling on the rope 7. By using a pulley system 6 the force required to move the magnet 4 from the first position to the second position is appreciably less than the force that would be required for an apparatus without a pulley system, for example one simply relying on a rope to move the magnet 4. In this embodiment the rope 7 is located within a pole 8, which could be a collapsible pole. The pole 8 functions as the tether for the apparatus 1, which enables introduction of the housing into the body of water, and then the retrieval of the housing, and any object attached thereto. The apparatus may also comprise a flexi joint 9.

The magnet 4 may be a rare earth magnet, and the nonmagnetic encasing and the non-magnetic housing may be made from plastic such as acrylic. The housing 2 is of sufficient dimensions to allow the encased magnet 4 to move up and down, which is enabled by a force being applied to the pulley system 6 to move to the second position and the spring loaded system 5 returning the magnet 4 to the first position.

In this embodiment there is a small gap of between 3 to 5 mm between the base section 3 and the magnet 4. This is to protect the magnet 4, with the base section 3 also preventing magnetic objects attaching directly on to the magnet 4.

The spring loaded system 5 ensures the magnet 4 returns to a ready position next to the base plate when the pulleys system 6 and rope 7 is not being used.

The pulley system 6 is a series of ropes and pulleys, which is attached to the rope 7 which feeds to a user at the surface. When the magnet 4 of this apparatus latches onto a large ferromagnetic structure the user need only apply a minimal force (or at least a lesser force as compared to the force that would be needed in a magnetic apparatus without a pulley system) at the surface to counter the magnetic force using the pulley system 6. By pulling on the rope 7, the user will cause the magnet 4 to move upwards further into the housing. The resulting increase in distance between the large ferromagnetic object and magnet 4 will reduce the strength/magnitude of the magnetic force/attraction between the object and the magnet, allowing easier detachment. This approach can also be used at the surface to detach clutter and or recover items of interest from the apparatus.

The apparatus may also be used to recover or retrieve objects from environments other than bodies of water, such as enclosed spaces, for example a mine shaft.

Claims

1. Recovery Apparatus for retrieving ferromagnetic objects from bodies of water comprising a magnet attached to a tether wherein the magnet is housed or encased within a non-magnetic housing and the magnet is further capable of being moved within the housing, from a first position to a second position, to enable the magnet to be distanced from the retrieved object and thereby the retrieved object to be detached from the apparatus.

2. A Recovery apparatus according to Claim 1, wherein the apparatus comprises a pulley system to enable the magnet to be moved within the housing, from the first position to the second position, in response to a force applied to the pulley system by a user of the apparatus.

3. A recovery apparatus according to Claim 1 or Claim 2, wherein the apparatus comprises spring loaded means biased to the magnet being held at the first position.

4. A recovery apparatus according to Claims 1 to 3, wherein the housing comprises a base, which is designed or arranged to contact with the object, and the first position is at a predefined distance from/above the base of the apparatus.

5. A recovery apparatus according to Claim 4, wherein the predefined distance between the first position and the base is between 2 mm and 20 mm.

6. A recovery apparatus according to Claims 1 to 5, wherein the tether comprises a pole, and the apparatus further comprises a rope for moving the magnet from the first position to the second position,.

7. A recovery apparatus according to Claim 6, wherein the rope is located within the pole.

8. A recovery apparatus according to Claims 1 to 7, wherein the apparatus further comprises a camera to view the object that the apparatus has attached to.