The present disclosure is related to a magnet activatable release apparatus. More specifically, the disclosure is related to an apparatus configured for holding a coupling device that is releasable connected to the apparatus, and that is released from the apparatus upon activating a release mechanism responsive to a magnetic force.

The apparatus is of particularly interest in situations wherein there is no or limited access to the apparatus, such as for example when the apparatus is used subsea, or in situations wherein there is limited access for an operator to operate the apparatus.

In use, the apparatus forms part of an assembly connected to an oblong object, such as for example a line or rope.

The invention is a result of a need for a simple, reliable an effective apparatus for facilitating release of for example a grapnel that has become stuck on a seabed. However, the apparatus according to the invention may alternatively be used for releasing or tilting an object that has been lowered to a desired position.

Publication US5207775A discloses device for unhooking a main anchor chain from a shank of an anchor for facilitating in releasing the anchor. An elongated plate has one end adapted to receive the last link of the anchor chain. The other end of the plate has an opening for receiving a shackle on the anchor. A second plate has a finger that covers opening thus making possible the hooking and unhooking of the shackle. A tube dropped from the boat runs freely over the main anchor chain to pivot the plates and uncover opening. This releases the shackle and therefore the anchor, so that it may be released. The finger is urged to its hooking position wherein the opening is closed, by means of a spring. The tube must have a mass sufficient so that the kinetic energy it acquires when running along the main anchor chain, can cause the two plates to pivot relative to each other when it is stopped by the device. That mass may range between 1 and 3 kilograms.

Publication US6209475B1 discloses an anchor connection and retrieving device. The device is adapted to be interposed between an anchor and one end of an anchor line, the anchor has a shank, a crown, and a plurality of flukes. The device has a locking assembly including a releasable portion, a locking portion relative to which the releasable portion is releasably coupled. One or more release pins are movable between a first position which couples the releasable portion to the locking portion and a second position which decouples the releasable portion from the locking portion. The locking portion is connected to the one end of the anchor line and a retrieving line is connected to it and the crown of the anchor. The releasable portion is coupled to the shank of the anchor. A release block may move along the anchor line to engage the release members to decouple the releasable portion from the locking portion.

Publication US3995577A discloses an apparatus and method for retrieving an ensnared marine device having an elongated shank, the shank having a crown end and a ring end, a primary line attached to the ring end and secured to the boat, a release element slidably mounted on the primary line adjacent the shank, a release line interconnecting the release element and the crown end, a coupling element slidable along the primary line for engaging the release element and comprising a guiding cavity for controlling the attitude of the coupling element during the sliding movement along the primary line and a coupling cavity, the coupling cavity comprising an entry portion and a locking portion, and a lifting line connected to the coupling element.

Publication US8904700 Bl discloses a fishing lure having a material that is magnetically attracted to a magnet slid down a fishing line connected to the lure. A movable hook shaft housed within the lure is spring loaded to a position where a free end thereof is captured within the lure and a hook attached to the hook shaft cannot be removed from the free end. When the magnet is slid down the fishing line and magnetically influences the magnetic material, the hook shaft is moved to a position where the free end thereof is exposed and the hook can be removed therefrom.

Publications EP0398740A1, US3809001A, US2010050918A1, and EP0102464A1 disclose various types of an anchor retrieving device that is activated by means of a weight element slidably mounted to a main anchoring line.

The prior art disclosed herein appears to rely on a activating a release mechanism by means of a weight element providing a certain kinetic energy.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.

The object is achieved through features, which are specified in the description below and in the claims that follow.

The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.

In a first aspect of the invention, there is provided a magnet activatable release apparatus comprising:

- a core having a first end portion and a second end portion;

- a support for carrying a releasable coupling device when connected to the apparatus;

-a locking device comprising at least one latch element for engaging the releasable coupling device when connected to the apparatus, the locking device being movable along a portion of the core between a locking first position, and a releasing second position;

- a drive element configured for providing a drive force urging the locking device towards the locking first position;

- a trigger member stopping device arranged between the locking device and the first end portion of the core; and

- a trigger member separable from the core of the apparatus and movable from a remote location to a position wherein the trigger member abuts against the trigger member stopping device; wherein one of the locking device and trigger member is made from a magnetic material, and the other one of the trigger member and the locking device is a magnet, the locking device and the trigger member being configured for providing a magnetic force exceeding the drive force provided by the drive element, so that when the trigger abuts against the trigger member stopping device, the locking device is urged towards the trigger.

In one embodiment, the locking device is magnetic, and the trigger member is a trigger magnet. In such an embodiment, the magnet activatable release apparatus comprises:

- a core having a first end portion and a second end portion;

- a support for carrying a releasable coupling device when connected to the apparatus; -a magnetic locking device comprising at least one latch element for engaging the releasable coupling device when connected to the apparatus. The magnetic locking device being movable along a portion of the core between a locking first position, and a releasing second position;

- a drive element configured for urging the magnetic locking device towards the locking first position;

- a trigger magnet stopping device arranged between the magnetic locking device and the first end portion of the core; and

- a trigger magnet separable from the core of the apparatus and movable from a remote location to a position wherein the trigger magnet abuts against the trigger magnet stopping device, the trigger magnet providing a larger magnetic force than the drive element, so that when the trigger magnet abuts against the trigger magnet stopping device, the magnetic locking device is urged towards the trigger magnet.

In an alternative embodiment, the locking device is a magnet, and the trigger member is magnetic.

Independently of being magnetic or a magnet, the locking device is configured for being moved from its locking first position to its releasing second position by means of magnetic forces between the locking device and the trigger. This has the effect that the operation of the apparatus depends on a strength of the magnet and a magnetic property of the material upon which the magnet acts. The locking device may be closer to the support when being in the locking first position than in the releasing second position.

In an embodiment wherein the locking device is magnetic, the drive element for urging the locking device towards the locking first position, may be selected from the group consisting of a mass of the magnetic locking device, a biasing means, and a magnet, or a combination of two or more thereof. Urging the magnetic locking device towards the locking first position by means of gravity may be effective in situations where the apparatus in a position of use is arranged substantially in a vertical position so that the magnetic locking device is urged to the locking first position by gravity. This may be regarded as a passive drive element. However, in situations wherein the apparatus during use may be temporarily in an inclined position, or even in a position wherein gravity tends to urge the magnetic locking device towards its releasing second position, there is a need for an active drive element such as a biasing means in the form of a spring or a drive element in the form of a magnet configured for urging the magnetic locking device towards the second end portion of the apparatus. Contrary to a spring, a magnet has the advantage of being a stationary element without any movable portions.

In an embodiment wherein the locking device is a magnet, the active drive element may be magnetic steel. Like the active drive element in the form of a magnet as discussed in the paragraph above, an active drive element in the form of magnetic steel is stationary without any movable portions.

In one embodiment of the invention is the support in the form of a protrusion extending radially with respect to the core of the apparatus. The protrusion may be in the form of an annular element. In an alternative embodiment of the invention is the support in the form of a bore extending for example radially into or through the core of the apparatus. In still another embodiment is the support in the form of a combination of a protrusion and a bore.

The apparatus may further comprise a movement restrictor arranged between the support and the locking device that may be magnetic or, alternatively, a magnet. The movement restrictor may be configured for at least reducing movement of the releasable coupling device along the core when the releasable coupling device is connected to the apparatus. The movement restrictor device thus has a function of at least reducing a risk of unintentional disconnection of a releasable coupling device connected to the apparatus. The movement restrictor may also serve as a stop member for the locking device, and as a support for the drive element configured for urging the locking device towards the locking first position.

In one embodiment is the movement restrictor in the form of a protrusion extending radially from a portion of the core.

In one embodiment is the movement restrictor further provided with guiding means for guiding the at least one latch element of the locking device.

In one embodiment, the movement restrictor may be in the form of a recess in a portion of the core, wherein the recess is configured for receiving a portion of the releasable coupling device when connected to the apparatus. Such a recess has the effect of at least reducing movement of the releasable coupling device along the core when the releasable coupling device is connected to the apparatus. An unintentional movement of the releasable coupling device along the core may drive the locking device towards its releasing second position and thus cause an unintentional disconnection of a releasable coupling device connected to the apparatus.

In a second aspect of the invention, there is provided an assembly comprising the magnet activatable release apparatus according to the first aspect of the invention, and a releasable coupling device comprising:

- a first portion provided with a recess for abutting against a portion of the core of the apparatus, the first portion further provided with a latch portion for receiving the at least one latch element of the locking device; and

- a second portion configured for connection to an object.

The latch element may in one embodiment be in the form of at least one peg protruding from a body of the locking device. In an alternative embodiment the latch element may be in the form of a sleeve portion protruding from a portion of the locking device. In still another embodiment, the latch element may be a combination of the at least one peg and the sleeve.

The assembly may further comprise an oblong object connected to the core of the apparatus, the oblong object being a guiding means for guiding the trigger member from the remote location towards the position wherein the trigger member abuts against the trig- ger member stopping device. The oblong object may typically be a line, a rope, or a chain, or a combination thereof.

The oblong object may in one embodiment of the assembly pass through the core of the apparatus so that the oblong object extends into the first end portion of the core and beyond the second end portion of the core. Alternatively to passing through the core of the apparatus, the oblong object may be connected to the first end portion of the apparatus, and a separate second oblong object may, if desired, be connected to the second end portion of the apparatus.

In one embodiment is the releasable coupling device provided with a fastening means for connecting the releasable coupling device to an object. The fastening means may for example be a shackle, a spring hook, or a line.

In a third aspect of the invention, there is provided a method for using the assembly according to the second aspect of the invention, wherein the method comprises:

- bringing the at least one latch element of the locking device into engagement with the latch portion of the releasable coupling device ;

- connecting at least the releasable coupling device to an object; and, when desired

- bringing the locking device from its locking first position to its releasing second position by guiding the trigger member from a remote location into abutment against the trigger member stopping device, whereby the releasable coupling device is allowed to disconnect from the apparatus.

The trigger member may typically be guided from the remote location by means of the oblong object connected to the core of the apparatus. The oblong object may typically be a rope or line.

In the following is described examples of preferred embodiments illustrated in the accompanying drawings, wherein:

Fig. la Shows a view of a magnet activatable release apparatus wherein a locking device is in a locking first position; Fig. lb shows the apparatus in fig. la after a trigger member has moved the locking device to a releasing second position;

Figs. 2a and 2b show a sideview and a top view, respectively, of an embodiment of the locking device;

Fig. 3 shows top view of a movement restrictor that may form part of the apparatus;

Figs. 4a and 4b show a sideview and a top view, respectively, of an embodiment of a releasable coupling device for use with the apparatus;

Fig. 5a shows the apparatus in fig. lb after the releasable coupling device shown in fig. 4a has been connected to the apparatus;

Fig. 5b shows a cut through A-A in fig 5a;

Fig. 6a shows the apparatus in fig. 5a seen partly in cut through A-A, and through

B-B of fig. 5 b;

Fig. 6b shows the apparatus in fig. 6a, after the trigger member has been moved away from a core of the apparatus;

Figs. 7a - 7c show an alternative embodiment of the releasable coupling device;

Figs. 8a and 8b show the apparatus in figs. 6a and 6b but with a cup-like locking device configured for use with the releasable coupling device shown in figs. 7a and 7b;

Figs. 9a and 9b show an example of use of the apparatus wherein the apparatus is operatively connected to an anchor or grapnel; and

Figs. 10 and 10b show an example of use of the apparatus wherein the apparatus is oper- atively connected to a pail. Any positional indications refer to the position shown in the figures.

In the figures, same or corresponding elements are indicated by same reference numerals. For clarity reasons, some elements may in some of the figures be without reference numerals.

A person skilled in the art will understand that the figures are just principal drawings. The relative proportions of individual elements may also be distorted.

In the figures reference numeral 1 denotes magnet activatable release apparatus according to the invention. The apparatus 1 comprises a core 3 having a first end portion 5, and a second end portion 7 opposite the first end portion 5. In operation of the apparatus 1, the first end portion 5 is oriented at a higher elevation than the second end portion 7.

In the embodiment shown, the core 3 is provided with a central through bore 4 for housing a portion of an oblong object, such as a rope or a line. However, it should be noted that the core 3 in an alternative embodiment (not shown) may be a solid body. In such an alternative embodiment the apparatus 1 is provided with connection means at least in its first end portion 5 for connecting to for example a rope. Such a connection means is configured for allowing passage of a trigger member 30 moved from a remote location to an operating position at a portion of the apparatus 1.

In the following discussion, the trigger member 30 is a magnet, and the locking device 20 is magnetic. However, it should be clear the in an alternative embodiment of the invention, the trigger member 30 is magnetic, while the locking device 20 is a magnet.

The apparatus 1 further comprises a support 10 for carrying a releasable coupling device 50 when connected to the apparatus 1. In the embodiments shown, the support 10 is connected at the second end portion 7 of the apparatus 1. However, in an alternative embodiment, the core 3 of the apparatus 1 may protrude beyond the support 10. Such an embodiment may be of particular interest if the core 3 is made of a solid material (without a passage) so that such a protruding portion of the core may be used for any connection means for connecting a rope or the like to the second end portion 7 of the apparatus 1, or if the core 3 is provided with a bore for receiving a releasable coupling device 50 provided with a cantilever element 58 protruding from a portion of the releasable coupling device 50, as indicated by dotted lines in fig. 7b and shown in fig. 7c.

The apparatus 1 further comprises a magnetic locking device 20 comprising at least one latch element 22 for locking the releasable coupling device 50 when connected to the apparatus 1. In figures la - 6b the latch element 22 is shown as pegs (two or three shown) protruding downwardly from a body 23 of the magnetic locking device 20. In figures la and 6b, an end portion of the pegs 22 is housed within bores 19 of the support 10.

Details of a first embodiment of the magnetic locking device 20 are shown in figures 2a and 2b wherein the body 23 is an annular element provided with a central bore 24 adapted to a diameter of the core 3 of the apparatus 1 for allowing movement of the magnetic locking device 20 along a portion of the core 3 between the locking first positions shown for example in fig. la, and the releasing second position shown for example in fig. lb.

In figures 8a and 8b, a second embodiment of the latch element 22 is shown. In figures 8a and 8b the latch element is in the form of a sleeve protruding from a periphery of the body 23 of the magnetic locking device 20. Although not shown in detail, it should be understood that the body 23 of the magnetic locking device 20 shown in figures 8a and 8b is similar to the body 23 shown in fig. 2b, i.e., with a central bore 24. The sleeve element 22 is provided with a recess 21 for housing a portion of the releasable coupling device 50 when connected to the apparatus 1.

In the locking first position, an inner portion of the latch element 22 in the form of a sleeve as shown in fig. 8b, is configured for abutting against a latch portion 55 (see figures 7b and 7c) of the releasable coupling device 50, thereby preventing disengagement of the releasable coupling device 50 from the apparatus 1.

As mentioned above, the magnetic locking device 20 is movable in a longitudinal direction along a portion of the core 3 between a locking first position as shown in figures la, 6b, and 8b, and a releasing second position as shown in figureslb, 5a, 6a, and 8a. In the locking first position, the magnetic locking device 20 is closer to the support 10 than in the releasing second position. Thus, if the apparatus 1 would always be oriented as shown for example in fig. la, i.e., with a longitudinal axis of the core 3 being substantially vertical, the magnetic locking device 20 would arrive at its locking first position simply by gravity. Therefore, a drive element configured for urging the magnetic locking device 20 towards the locking first position could be passive and based on a mass of the magnetic locking device. However, the apparatus 1 may in some situations have a slanted orientation. To provide a reliable positioning of the magnetic locking device, an active drive element is preferred. Such an active drive element could for example be a biasing means such as a spring (not shown), or one or more magnets configured to provide a force for urging the magnetic locking device 20 toward its locking first position. In fig. 3, the drive element is shown as three magnets 17 arranged evenly spaced-apart in a portion of a movement restrictor 16. The magnets 17 are arranged in recesses of the movement restrictor 16. The movement restrictor 16 is arranged between the support 10 and the magnetic locking device 20, as shown for example in fig. la.

It should be noted that in the alternative embodiment of the apparatus 1 wherein the trigger member 30 is magnetic, and the locking device 20 is a magnet, the three drive elements 17 shown in fig. 3 is magnetic steel elements integrated in recesses of a body of the movement restrictor 16. In such a case, the body of the movement restrictor 16 may be made from a non-magnetic material. Alternatively, the body of the movement restrictor 16 may be made of a relatively weak magnetic material as compared with the magnetic strength of the trigger member 30. In such a case, the drive elements 17 may be superfluous.

Turning back to the embodiment wherein the trigger member 30 is a magnet, and the locking device 20 is magnetic, the apparatus 1 comprises a trigger member stopping device 14 arranged between the magnetic locking device 20 and the first end portion 5 of the core 3. In the embodiments shown, the trigger member stopping device 14, hereinafter denoted trigger magnet stopping device 14, is in the form of a washer secured for example to a circlip groove (not shown) of the core 3. To operate the magnetic locking device 20, the apparatus 1 further comprises a trigger magnet 30 being separable from the core 3 of the apparatus 1. The trigger magnet 30 serves the function of an "unlocking key" that is configured for urging the magnetic locking device 20 from its locking first position to its releasing second position when the trigger magnet 30 abuts against the trigger magnet stopping device 14. The trigger magnet 30 is configured to provide a magnetic force exceeding a force provided by the drive element of the apparatus, independently of the drive element being a gravity force plus any force from a biasing element as discussed above, and/or the magnets 17 as shown.

Turning now to figures 9a - 10b showing examples of the apparatus 1 according to the invention used for two different purposes.

In figures 9a and 9b the apparatus is operatively to an anchor or grapnel G located at a seabed SB.

Fig. 9a shows a situation wherein an arm A of the grapnel G has hooked a cable C initially resting on the seabed SB. A free end or top portion of a shank S of the grapnel G is connected to the releasable coupling device 50 secured to the apparatus 1 having its magnetic locking device 20 in its locking, first position, i.e., the position shown for example in figures la and 6b. An anchor line LI extends from a boat (not shown) on a surface of a sea and enters the first end portion 5 of the core 3 of the apparatus 1. Thus, the anchor line LI is operatively connected to a free end of the shank S of the grapnel G via the apparatus 1, the releasable coupling device 50, and a shackle (not shown). The shackle is connected to the releasable coupling device 50 via an aperture 56 in the second portion thereof.

A release line L2 connects a crown CR of the grapnel G to the second end portion 7 of the core 3 of the apparatus 1. The anchor line LI and the release line L2 may be the same line wherein the anchor line LI extends through the bore 4 of the core 3. However, the anchor line Llis arranged to prevent the apparatus 1 from sliding downwards with respect to the lines LI, L2.

In an alternative embodiment, the anchor line LI and the release line L2 may be separate lines, i.e., the apparatus 1 is interposed between the anchor line LI and the release line L2.

Thus, the grapnel G is connected to apparatus 1 via two lifting points; a primary lifting point at the free end of the shank S; and a secondary lifting point at the crown CR of the grapnel G.

To release the grapnel G from its engagement with the cable C, a trigger magnet 30 has been threaded onto the anchor line LI at the surface and is shown sinking along the anchor line LI towards the apparatus 1.

Although not shown specifically, it should be understood that the trigger magnet 30 may be "splitable" or "openable" to facilitate connecting the trigger magnet 30 onto the anchor line LI.

In fig. 9b, the trigger magnet 30 has urged the magnetic locking device 20 from its locking first position to its releasing second position whereupon the releasable coupling device 50 has been released from the apparatus 1. Thus, the grapnel G is connected to the anchor line LI only via the secondary lifting point at the crown CR of the grapnel G. When pulling the anchor line LI from the surface, the grapnel is tilted, and the arm A of the grapnel is threaded out of engagement with the cable C. When retrieved at surface, the releasable connection device 50 may be reconnected to the apparatus 1 simply by bringing the releasable connection device 50 into engagement with the apparatus 1 and moving the trigger magnet 30 away from the apparatus 1.

Although figures 9a and 9b show the apparatus 1 used for releasing a stuck anchor or grapnel, the apparatus 1 is suitable also for releasing other objects. One example of such an object is a fishing gear such as a crab- or lobster pot wherein it is possible to change from a primary lifting point to a secondary lifting pint.

Figures 10a and 10b show an alternative use of the invention. In the fig. 10a a bucket B for carrying a substance has been lower to a desired location, and the trigger magnet 30 is on its way towards the apparatus 1. In fig. 10b, the trigger magnet 30 has urged the magnetic locking device 20 from its locking first position to its releasing second position as discussed above, whereupon the releasable coupling device 50 has been released from the apparatus 1 and the bucket B has turned upside down and any substance carried by the bucket B is emptied therefrom.

The apparatus 1 may also be used without the line L2 shown for example in figures 10a and 10b. In such a use, the apparatus 1 may be utilized for lowering the bucket B (or any other object) to a desired base (not shown) and then release the bucket B from the apparatus 1. A release of the bucket B from the apparatus 1 may also be achieved threading the line L2 via the handle (instead of securing the releasable coupling device 50 to the handle as shown in figures 10a and 10b), by securing an end portion of the line L2 to the releasable coupling device 50. An advantage of such a solution is that the releasable coupling device 50 is still secured to the apparatus 1 via line L2 after release of the bucket B. Thus, the apparatus 1 may be used repeatedly without having to replace the releasable coupling device 50.

Being activated by a magnetic force only, the operation of the apparatus 1 according to the invention is very reliable. The apparatus 1 also comprises only one movable part (the locking device 20) in addition to the trigger member 30. The apparatus 1 is therefore also durable and very easy to "reload" after having been activated.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.