Lifeboat release and retrieval system (LRRS)

A lifeboat hook assembly comprising a hook-shaped beak (5) and a release mechanism (6), said hook shaped beak (5) is rigidly connected to a lifeboat (2) at one end, said hook shaped beak (5) having a downwardly oriented shoulder (18) against which a loop (17) is adapted to rest so that the lifeboat is suspended in said loop (17), said release mechanism (6) is coupled to the hook-shaped beak (5) and is adapted to move relative to the hook-shaped beak (5) between a locked position (8a, 10a) wherein the loop is prevented from escaping from the shoulder (18), and a releasing position (8e, 10e) wherein the loop (17) is allowed to escape from the shoulder (18), an actuator (11) is coupled to the release mechanism (6) and is adapted to move the release mechanism (6) between the locked position (8a, 10a) and the releasing position (8e, 10e). The invention being distinctive in that said hook shaped beak (5) or said release mechanism has a first guide slot (7) and a second guide slot (9), said other of said hook shaped beak (5) or release mechanism (6) has a first guide pin (8) and a second guide pin (10), said first guide pin (7) being adapted to engage with the first guide slot (8), said second guide pin (10) being adapted to engage with the second guide slot (9).

FIELD OF THE INVENTION

The present invention relates to a coupling suitable for handling of loads such as lifesaving equipment.

More particularly the present invention relates to a release and retrieval system with a mechanism adapted to release or retrieve of liftable installations such as lifeboats that are lowered to the surface of the sea from vessels, platforms, rigs etc., or lifeboats of the free fall type, which under launch are free falling from vessels, platforms, rigs etc.

The release and retrieve system has both on-load and off-load functionalities.

BACKGROUND OF THE INVENTION AND PRIOR ART

The UN's International Maritime Organization IMO introduced requirement for on-load release hooks on all ships applicable for all ships built after Jul. 1, 1986 to ensure that the lifeboats could be released easily and quickly in an emergency evacuation situation.

There are three types of lifeboat releasing mechanism, on-load and off-load release and release hooks for free fall lifeboats. The first two mentioned mechanisms release the lifeboat from the lowering mechanism or davit, which is attached to a wire or loop. By releasing the loop, the lifeboat can be set free to propel away from the ship.

Lifeboats with off-load mechanism may only be released when the lifeboat is into the sea and fully buoyant and hence the fall is un-loaded. Release require manual action by the lifeboat crew—a dangerous action often proved difficult as even un-loaded falls may be influenced by outside forces from the mothership's possible remaining speed through the water, wind, waves, heeling etc.

An on-load mechanism can release the lifeboat from the wire, with the lifeboat above the water level and with all the crewmembers onboard the boat. The load will be still on the fall as the lifeboat would not have touched the water. A release handle or similar is provided onboard inside the lifeboat to operate this mechanism.

The third release mechanism is hook for free-fall lifeboats. In these types of lifeboats there is only one hook, arranged at the rear end of the lifeboat, holding the lifeboat. When this hook is released, the lifeboat drops into the water.

Traditionally, lifeboats were suspended from two off-load hooks. It is therefore impossible to release loaded hooks, and it could also be problematic to release the hooks with certainty and simultaneously, even with the lifeboat in the water, especially during evacuation in high seas.

There are many weaknesses also with the existing on-load release systems. There have been cases where the lifeboats have dropped during exercises, both during lowering and hoisting, with or without people onboard. These accidents often occur from the deck of the ship when the lowering or lifting process gets to a stop or a significant jerk occurs.

There could also be a failure because the on-load hooks are not properly reset. These hooks can release unintentionally when hoisting the lifeboat or during the next lowering of the lifeboat.

There is also a problem that one of the hooks may release unintentionally alone or before the other one releases. This has on occasions led to a situation where the lifeboat has fallen upside down into the water.

Other reasons for failure are lack of maintenance of the hooks or an overly complex construction of the on-load hooks, so that there is a risk that the parts of the hooks are not assembled correctly.

Lack of skills of the person who is to release or secure of the on-load hooks is also a cause for accidents.

Other reasons for failure of on-load hooks are the use of wrong materials in the hooks.

Due to the many dramatic accidents, some of them fatal, with the new on-load release mechanisms, the IMO has changed the regulations, so that it is no longer a requirement to have people aboard lifeboats during the lowering and reversible handling during exercises. This has led to fewer accidents, but has increased the seafarers' skepticism to the lifeboat as a lifesaver. Is it considered dangerous to be in the lifeboat during exercise, leading to the view that it is even more dangerous to be in the lifeboats during emergency situations.

Publication US20120125252 shows a coupling for coupling a fall to a lifeboat. The coupling comprising a locking portion that has the shape of a spherical ball and a receiving portion shaped as a hollow. In the locked position, the locking portion is secured within the receiving portion by a spring or a pawl when the fall is slack. To release the locking portion from the receiving portion, actuators are pushing the locking portion from the receiving portion. When the fall is slack it is just the spring or pawl that is preventing the release of the locking portion. If there is a failure in the spring or pawl, this could lead to unintentional release. There is also no easy retrieval of the coupling without the use of hands.

Publication U.S. Pat. No. 4,610,474 shows a release hook for lifeboats. It comprises a hook with spaced apart guide pins. Supporting plates with spaced apart guide slots are affixed to the lifeboat. The guide pins of the hook are engaging in the guiding slots of the supporting plates, and the hook is adapted to move between a loop-engaging loaded position and a loop disengaging position. The hook is also the release mechanism and is moved within the guide slots by a piston pushing against the lower part of the hook. A bolt pin or stop secures the cable or chain link attached to the lowering arrangement inside the hook. In this publication, the cable or chain link is attached to the movable hook and the hook is also receiving the total load acting on the hook arrangement.

This results in an undesirable and dangerous strain on the hook as the moveable hook has to carry the full load of the lifeboat, a failure in the hook could result in an accidental release of the hook and lifeboat from the lowering arrangement.

GB292259 and GB225591912 both shows another lifeboat hook assemblies comprising a hook-shaped beak and a release mechanism, the release mechanism is adapted to move relative to the hook shaped beak between a locked position and a released position.

In publication GB292259, the hook shaped beak having a guide pin slidably connected to a guide slot in the release mechanism.

None of the publications shows a lifeboat hook assembly where the release mechanism having at least two guide pins adapted to engage with corresponding guide slot in the hook shaped beak. This provides a more reliable and secure hook assembly than the previous publications.

Objective of the Invention

The objective of the present invention is to minimize the risk of failure and accidental release when lowering or hoisting a lifeboat attached to lifting arrangements. The hook should work securely as expected in various situations.

It is also an objective of the present invention to have a construction where there are no moving load bearing parts, which will provide an improved sustainability.

It is also an objective of the invention to meet current requirements and future requirements of lifeboat hooks for both davit and free fall lifeboats. It is another objective of the present invention to provide a construction where the release mechanism does not have to carry the weight of the lifeboat. Other on-load hooks need a momentum to operate as expected. The construction should also work equally well in on-load and off-load release situations.

It is another objective of the present invention to provide a construction where the release mechanism is unloaded in the locked position and a force has to be applied to the mechanism to move it out of this position.

This results in reduced danger for inadequate use, unintended release and inadequate locking.

The undercut shape of one of the guide slot results in that the release mechanism is held in the locked position until the force is applied by the piston arrangement or the actuator.

Another objective of the present invention is to reduce the physical handling when lowering or lifting a lifeboat. There should also be no need for applying great force from persons onboard the lifeboat to release the lifeboat.

It is another objective of the present invention to provide an easy reverse action without use of hands on the hook components to retrieve the lifeboat after evacuation drills.

This will also reduce the physical handling of the operation and minimize injuries and accidents. A wire or rope could also act as an anchor pile to the support vessel, mother ship or similar where lifeboat is released from to prevent the lifeboat to slip away.

It is another objective of the present invention to provide an arrangement where simultaneous release of both of the hook arrangement on the lifeboat are ensured.

It is yet another objective of the invention to obtain a construction that have corrosion resistant materials and also have a simple and visible function with few components and is easy to maintain.

It is yet another objective of the invention to provide an arrangement that is designed for extreme conditions, including icing, etc.

The force applied from the actuator could break ice-crystals on the hook arrangement.

SUMMARY OF THE INVENTION

The invention relates to a lifeboat hook assembly comprising a hook-shaped beak and a release mechanism, said hook shaped beak is rigidly connected to a lifeboat at one end, said hook shaped beak having a downwardly oriented shoulder against which a loop is adapted to rest so that the lifeboat is suspended in said loop, said release mechanism is coupled to the hook-shaped beak and is adapted to move relative to the hook-shaped beak between a locked position wherein the loop is prevented from escaping from the shoulder, and a releasing position wherein the loop is allowed to escape from the shoulder, an actuator is coupled to the release mechanism and is adapted to move the release mechanism between the locked position and the releasing position. The invention is distinctive in that said hook shaped beak has a first guide slot and a second guide slot, said release mechanism has a first guide pin and a second guide pin, said first guide pin being adapted to engage with the first guide slot, said second guide pin being adapted to engage with the second guide slot.

This provides a safe and reliable hook arrangement for releasing and retrieving of a lifeboat.

A first and second guide slots with guide pins provides safe and steady movement of the release mechanism of the hook arrangement.

This also provides a sufficient torque in the movement of the release mechanism, for instance to break ice-coating which has settled on the hook arrangement.

Preferably, a lifeboat hook assembly having a loop displacing mechanism adapted to push the loop away from the shoulder.

This provides a second safety arrangement where the loop is adapted to rest on the shoulder in the locked position in addition to the locked position of the beak. A displacing mechanism must push the loop from the shoulder in order to release the loop from the hook arrangement.

Preferably, the loop displacing mechanism comprises an edge connected to the release mechanism.

This provides an easy and safe arrangement where the moving of the wedge tip to a releasing position and the displacing mechanism operates simultaneously to release the loop.

Preferably, the guide pins are movable along the respective guide slots.

This provides a movement of the release mechanism defined by the shape of the guide slot.

Preferably, a first end of the first guide slot has an undercut.

This provides a self-locking of the hook in the locked position since the piston arrangement has to force the first guide pin out of this position to release the loop.

Preferably, the actuator is adapted to move in the direction along the hook arrangements main axis.

This provides an arrangement that provides sufficient force to the release mechanism towards a release position.

Preferably, the second slot is shaped as an elongated slot extending along the main axis of the hook arrangement with a slightly curved second end.

This provides a stabilizing arrangement and prevents lateral movement towards the cylinder.

Preferably, the actuator is hydraulic.

This provides a safe and reliable releasing or locking of the hook arrangement and minimizes the physical handling of the hook arrangement and prevents therefore accidents etc. The force applied to the release mechanism could also be greater than hand power.

Preferably, one hook assembly is arranged on the lifeboat.

This provides a hook arrangement that is suitable for free fall lifeboats.

Preferably, two hook assemblies are arranged at each end of the lifeboat for simultaneous operation.

This provides a hook arrangement that is suitable for off-load or on-load release of two hook arrangements simultaneously.

Preferably, a first safety bore is arranged on the top of the hook-shaped beak and is adapted to engage with a securing element.

This provides a mechanical safety mechanism for maintenance of the hook arrangement or testing of the hydraulic system.

Preferably, second safety bore mechanism is arranged on the release mechanism and is adapted to engage with a stick or lever for manually rotating the release mechanism.

This provides a mechanical safety mechanism by for instance maintenance of the hook arrangement or testing of the hydraulic system, to move the release mechanism mechanically or to hold the release mechanism in a preferred position mechanically.

Preferably, the plate safety bore of the release mechanism, and a corresponding beak safety bore of the hook-shaped beak are adapted to engage with a stick or lever for securing the release mechanism in one position.

This provides an additional safety arrangement to maintain the hook arrangement in the locked position.

Preferably the guide slots are formed in the hook-shaped beak.

Preferably the actuator is coupled to a linear solenoid.

DETAILED DESCRIPTION

The term upper and lower in the description must be interpreted in the broadest sense and is defined in view of the orientation of the parts in the appended drawings. These parts could have other orientations than defined when the invention is in use.

The main axis of the hook-arrangement is defined as a line extending from the first part of the hook-shaped beak5ato the second part of the hook shaped beak5b. This line is perpendicular to the lifeboat deck14. InFIG. 2this is a substantially vertical line.

FIG. 1Ashows a lifeboat2suspended from a loop or chain link17attached to a lowering arrangement or fall, such as a davit and a tackle4. One end of the tackle4is attached to a ship, platform or other devices that requires a lifeboat2. At the other end there is arranged a chain assembly3with a loop, such as a chain link17at the free end. A wire or other arrangement suitable for securing the lifeboat2to the tackle4is also possible suspension arrangements. The chain link17is releasable connected to the lifeboat2through a hook assembly1. The hook assembly1is attached to the lifeboat2. There could be arranged only one hook arrangement1at the rear end of the lifeboat2, if the lifeboat is a freefall lifeboat. As shown inFIGS. 1B-1C, there could also be arranged two similar hook arrangements1,1′ at each of the front and rear end of the lifeboat2. In special cases, also more than two hook arrangements are possible. Each of the hook arrangements1,1′ are attached to separate sets of tackle4and chain3arrangement.

FIG. 1Ashows a lifeboat2with two hook assemblies1,1′. The two hook assemblies may be arranged at each end of the lifeboat for simultaneous operation. The lifeboat is hanging from just one of the hooks1, the other hook1′ is released from the chain link17′.

The Figure shows an emergency position of the lifeboat where the lifeboat traditionally would have fallen into to the sea.

FIG. 2shows the hook assembly1attached to the chain link17in detail. The hook assembly1comprises a hook-shaped beak5and a release mechanism6.

A first part of the hook-shaped beak5ais situated above a lifeboat deck14; a second part of the hook-shaped beak5bis situated below the lifeboat deck14.

Both the first part of the hook shaped beak5aand the second part of the hook shaped beak5bare rigidly connected to the lifeboat14.

The second or lower part of the hook-shaped beak5bis attached to the lifeboat2through fixing means that are known per se. The second part of the hook-shaped beak5bhas two through holes13aadapted to be connected to the fixing means15with bolts and nuts.

The fixing means could take many different shapes; some of the possible shapes are illustrated inFIGS. 2-9. In general, the upper part of the fixing means has openings13acorresponding with the through holes13aof the second part of the hook-shaped beak5b.

InFIG. 2the fixing means is a bar15awith through holes13athat is connected directly to the hook-shaped beak5b.

InFIGS. 4 and 5the fixing means comprises a bar15bconnected to a bracket15c. The bracket15chas openings13athat corresponds with the through holes13aof the hook-shaped beak5b.

InFIG. 6the fixing means comprises of a bracket15dand several bars15efixedly connected to the bracket15d.

InFIG. 7there are arranged two similar bars with brackets15f,15g. The brackets15f,15ghave openings that correspond with the through holes13aof the second part of the hook-shaped beak5b, and are connected at each of the sides of the hook-shaped beak5b.

The through holes13aare vertically aligned with the chain link as the arrows inFIG. 2indicates.

The first part of the hook shaped beak and the second part of the hook shaped beak are both coupled to the lifeboat deck14through fixing means known per se, for instance through bolts or similar as shown inFIGS. 3band3c.

FIGS. 2-7show a cylinder28attached to the lifeboat deck14. The cylinder28could be supported by a bracket arranged between the cylinder28and the second part of the hook shaped beak5bto support the cylinder (not shown) or a bracket29arranged between the hook shaped beak5band conduits30supplying hydraulic fluids to the cylinder28. This embodiment is illustrated in the drawings. The cylinder28is in this embodiment fixedly attached to the lifeboat2.

The cylinder28is a part of a hydraulic piston arrangement11or actuator. There is arranged a piston31within the cylinder28, the piston31is adapted to move within the cylinder28depending on the amount of hydraulic fluid forced into the cylinder28. The piston31is attached to the release mechanism6as shown inFIG. 2. The movement of the piston31leads therefore to a movement of the release mechanism6.

The hydraulic cylinder is fixed to the release mechanism and have a possibility of 1 mm lateral movement in the fixings of the piston rod to the release mechanism. This prevents strain on the piston rod. The clearance is illustrated inFIG. 2.

Other power transmission arrangements suitable for the arrangement are also possible instead of the hydraulic piston arrangement11. It is for instance possible to use a wire or similar to push the release mechanism to the release position.

There are shown two conduits30in theFIG. 2to supply a hydraulic fluid into the cylinder28and also the return of the hydraulic fluid from the cylinder28.

FIG. 2shows the first part of the hook-shaped beak5a, with a shoulder18arranged on the hook-shaped beak5a. The shoulder18has horizontal, gently sloping length, which ends in a tip32. The shoulder18has a length that is larger than the cross-sectional diameter of the chain link17. The shoulder18is arranged so that it makes it possible for the hook-shaped beak5a,5bto hang from the chain link17without any devices securing the chain link17(provided the hook-shaped beak is oriented substantially vertical). In order to obtain this, the chain link17must be arranged resting only on the shoulder18, as shown inFIG. 2, not both on the shoulder18and the release mechanism6as shown inFIG. 4. InFIG. 4the lifeboat2would drop if the release mechanism is moved away from the shoulder tip32.

The release mechanism6having a wedge12cenclosing the chain link17when the hook arrangement is in a closed position. A tip of the wedge19is in this position close to the shoulder tip32of the beak5.

FIGS. 2 and 4show the different hanging positions of the hook1relative to the chain link17.

FIG. 2shows a hanging position where only the shoulder18is in contact with the chain link17, and there is no strain on the wedge12c.

FIG. 4shows another possible position of the hook1and chain link17. In this position, the hook1has been pivoted relative to the chain link17, and the chain link17is arranged on the tip of the shoulder32. The small distance between the tip of the wedge19and the tip of the shoulder32secures the chain link17within the cavity of the hook1.

TheFIG. 2also shows slots7and9. A first guide slot7and a second guide slot9are arranged on the first part of the hook-shaped beak5a, the first guide slot7is situated above the second guide slot9at a distance spaced apart from the second guide slot9.

In addition to the guide slots7,9there could be arranged a first safety bore22at the top or near the top of the first part of the hook-shaped beak5aand a second safety bore mechanism16a,16bbetween the guide slots7,9on the first part of the hook-shaped beak5a. The first safety bore22is adapted to receive a shackle39or similar arrangement and could be used as a safety device during maintenance of the hook1. This is further described in relation toFIG. 9.

The second safety bore mechanism16a,16bis adapted to receive a pin or a suitable tool (not shown) acting as a fuse for manually preventing movement of the release mechanism6.

The release mechanism6shown inFIG. 2is further described with reference toFIGS. 3a-c. The release mechanism6is designed with two parallel plates12a,12b. The plates12a,12bare arranged one on each side of the first part of the hook-shaped beak5aand are provided with guide pins8,10. These guide pins8,10extends between the plates12a,12band are adapted to engage the guide slots7,9in the beak. The guide pins8,10are adapted to move within the guide slots7,9. A first guide pin8is adapted to move within the first guide slot7, a second guide pin10is adapted to move within the second guide slot9.

An opposite arrangement is also possible, where the slots are arranged on each of the plates12a,12b. The guide pins could in this embodiment extend from the first part of the hook-shaped beak5aat both sides (not shown).

A piston connector34is arranged between the plates12a,12bat the lower part of the plates12a,12band is adapted to engage with the piston31.

The guide pins8,10and the piston connector34are connected to a guide pin bracket35arranged on the outside of one of the release plates12a,12bas shown inFIG. 3a. This guide pin bracket35secures the guide pins and the piston connector34in the arrangement. The bracket is adapted to engage with grooves in the guide pins to secure the guide pins and the piston connector34.

The second safety bore mechanism16a,16bcomprising a plate safety bore16bat each of the plates12a,12b. These plate safety bores16bare adapted to correspond with a beak safety bore16aon the hook-shaped beak5. These second safety bore mechanism16a,16bare adapted to receive a cotter bolt or similar pin to manually prevent movement of the release mechanism6in relation to the beak5.

It is also possible to place sticks or levers101into each of the plate safety bores16band manually rotate the release mechanism6.

FIGS. 3a-3calso show the wedge12carranged between the two plates12a,12b. The wedge12cis situated as an extension of the outer leg in a U-shaped part12dof the release mechanism6. The inner leg is defined as an edge20′. A tip19of the wedge12cis adapted to be arranged near the tip32of the shoulder18when the hook1is in the locked position. The locked position is shown inFIG. 3c. The position is also schematically shown inFIGS. 2 and 3. In this position the chain link17is secured within a cavity21defined by the U-shaped part of the release mechanism6and the shoulder18.

A releasing position of the hook1is shown inFIG. 3b. In this position, the wedge tip19is moved a distance away from the shoulder tip18. This position is also schematically shown inFIGS. 8 and 9.

The actuator or hydraulic piston arrangement11is arranged on the opposite side of the release mechanism6from the wedge12c. The piston31is connected to the release mechanism through the piston connector34.

FIG. 2shows the hook in the locked position as described earlier. The first guide pin8is in this position defined to have a position8aarranged in the first end7aof the guide slot7. The second guide pin10is defined to have a position10ain the first end9aof the second guide slot9. In this locked position the inner wall20of the hook-shaped beak5is congruent with the edge20′ at the inner side of the cavity21.

FIGS. 2 and 4show the hook arrangement in the locked position where the chain link is held in a secured position within the hook arrangement1.

FIGS. 5, 6 and 7show a first, a second and a third intermediate position between the locked position and the releasing position of the hook arrangement1.

To achieve these positions the actuator or piston arrangement11will force the release mechanism6towards a released position. In each of this positions, the guide pins8,10are moved from the first end7a,9aof the guide slots7,9(shown inFIGS. 2 and 4) towards a second end7b,9bof the guide slots (shown inFIG. 8). The wedge12cis moved down and away from the shoulder tip32through these position. In the first intermediate position, the guide pins8,10have the positions8b,10bin the guide slots7,9as shown inFIG. 5.

In the second intermediate position, the guide pins8,10have the positions8c,10cin the guide slots7,9as shown inFIG. 6.

In the third intermediate position, the guide pins8,10have the positions8d,10din the guide slots as shown inFIG. 7.

FIGS. 8 and 9show the hook1in the released position. In this position the first guide pin8is arranged at the second end of the guide slot7bin a position defined as8e. The second guide pin10is arranged at the second end of the second guide slot9bin a position defined as10e.

In the released position, there is a gap33from the shoulder tip32to the tip of the wedge19. The gap33is larger than the chain link17so that the chain link17can escape from the hook arrangement1.

When the release mechanism6rotates towards the released position, the edge20′ at the inside of the U-shaped part of the release mechanism6moves towards the shoulder tip32. The edge20′ pushes the chain link17towards the shoulder tip32and thereby releases the hook arrangement and thus the lifeboat2from the chain link17.

TheFIGS. 2-9show that the hook-shaped beak5has the same position in all figures. It is the movement of the release mechanism6that causes the different positions of the hook1.

The hydraulic piston31applies a vertical force on the end or beneath the release mechanism6. The release mechanism6is then forced by the actuator or piston arrangement to move a distance. The guide pins8,10are forced to move along the geometry of the guide slots7,9so that the movement of the release mechanism is rotary like.

This is shown inFIGS. 5, 6 and 7as the first, second and third intermediate positions8b,8c,8dof the guide pin8, between the locked position8aand the releasing position8e. The first guide slot7has a curved shape, for instance as shown in theFIG. 4-8.

As shown inFIG. 4there is an undercut at the end7aof the first guide slot7.

A tangential line26in the upper contact point25abetween the first guide slot7and the first guide pin8, has in this position a negative angle in relation to a vertical line through the same contact point25a. When the first guide pin8is moved within the first guide slot7the angle between the vertical line and the tangential line is decreasing until the angle is zero in a position between the locked position8aand the first intermediate position8b. The angle will increase in the positions after this. This means that the force has to be largest in the beginning to force the first guide pin8out of the locked position8auntil the defined angle is zero.

The movements of the first guide8in the vertical and horizontal directions are illustrated in theFIGS. 5-8. From the locked position8ato the first intermediate position8b, the first guide pin8and the piston31is moved a distance approximately 20 mm in the vertical direction, but the displacement is only approximately 1.5 mm in the horizontal direction.

From the first intermediate position8bto the second intermediate position8c, the first guide pin8is moved a distance approximately 20 mm in the vertical direction and the displacement is approximately 12-13 mm in the horizontal direction.

From the second intermediate position8cto third intermediate position8d, the piston31and the first guide pin8is moved a distance approximately 20 mm in the vertical direction and a further displacement of approximately 14, 5 mm in the horizontal direction.

From the third position8dto the releasing position8e, the first guide pin8and the piston31is moved a distance 8 mm in the vertical direction and a further displacement of approximately 14.5 mm in the horizontal direction.

In this embodiment the movement from 0-40 mm of the piston rod31in the vertical direction the chain link17is secured in the hook arrangement1.

The movement of the piston rod31from 40-55 mm in the vertical direction is defined as a release phase. When the piston rod has moved from 55 mm to 70 mm the hook arrangement is in open and the chain link is released from the hook arrangement1.

The displacements lengths above are just illustrative examples of how the horizontal displacement increases towards the releasing position and that the force is large in the beginning and is decreasing towards the released position. The displacement in the horizontal direction is small in the beginning but increasing towards the released position.

Other shapes of the first guide7slot or the second guide slot9and actuator arrangements will give other displacements in the horizontal and vertical direction.

The second guide pin10correspondently moves along the second guide slot9from the secured position10athrough the first, second and third positions10b,10c,10dto the releasing position10e. The different positions are shown inFIGS. 4-8.

The second slot9is shaped as an elongated substantially vertical slot and slightly curved at a second end9bfacing the first guide slot8. When the actuator11is moving the release mechanism6upwards, the second guide pin10tends to move in the same direction as the actuator11but is forced to move along the surface of the second guide slot9.

After the lifeboat has been released from the chain link17, the reversed operation can be performed to retrieve the chain link17in the hook1and lift the lifeboat2back to the initial position.

This operation is shown inFIGS. 8 and 9. A rope or wire41could be attached to the chain link17as an assistance rope. The rope41extends via a pin40to a mechanism (not shown) that is pulling the rope41until the chain link17is positioned within the cavity21. The mechanism could be mechanical or electrical or just hand force to pull the chain3back towards the hook arrangement1.

The rope or wire is preferably arranged in the hook arrangement and the chain link before the lifeboat is released to obtain an easy retrieval of the lifeboat.

The wire or rope could also act as a coupling between the mother ship and the lifeboat after the lifeboat has been released.

The rope41could be arranged in different ways between the chain link17and the hook1. The rope41could be arranged in a multiple different ways to the hook arrangement like tied with a knot directly to the chain link17as shown inFIG. 8or attached to a pin40on one side of the hook1, the rope41extends in this case through the chain link17and back to a pin (not shown) arranged on the opposite side of the hook1. The pins40could be attached to the beak5, the release mechanism and arranged on a bow shaped device arranged on the outside of the wedge12c(not shown). This prevents accidents like crushing when the chain link3is moved back into the cavity21as well as it helps guiding the chain link21into a suitable position towards the cavity21.

FIG. 10shows a maintenance position where the release mechanism6and the actuator are removed. In this position, there is no securing of the chain link17and it is possible that the chain link17could slip from the shoulder18. To prevent the lifeboat from falling, there is arranged a wire42, also referred to as a securing element, between the ship and the shackle15.

FIG. 11aandFIG. 11bshow an example of different hanging positions of the lifeboat with hook arrangement1. InFIG. 11athe shoulder18and release mechanism6is facing upwards and the release mechanism6is actively securing the chain link17in the cavity21.

InFIG. 11bthe shoulder18and release mechanism6is facing downward and the chain link17is resting only on the shoulder18. The release mechanism6is passively securing the chain link17within the cavity21.

FIG. 12shows schematically the actuator system arranged in a free fall lifeboat with one hook. A tank50or reservoir is filled with hydraulic fluid. The container is connected to a hydraulic pump51and emergency hydraulic pump52in case of failure of one of the hydraulic pumps. The pumps can be operated both electrically and by manual pumping, using handles53. The hydraulic fluid flows through a pressure gauge and an automatic three-way valve to the cylinder31. The increasing fluid pressure in the cylinder is pressing the piston31away (upwards) from the bottom of the cylinder. There are three zones in the cylinder. When the cylinder has a small amount of hydraulic fluid in the cylinder (below the piston), the hook is in the secured position. When the amount of hydraulic fluid exceeds a certain level in the cylinder, the hook is in the releasing phase (intermediate positions). When the amount of hydraulic fluid exceeds this level, the hook is in the released position. The hook can be brought back to the secured, locked position by letting the hydraulic fluid back into the hydraulic tank50. In this process, the hydraulic tank50supplies one hook assembly1, like in a free-fall lifeboat.

FIG. 13shows another actuator system for a conventional lifeboat with two hooks, schematically. It has a similar structure as the actuator system inFIG. 11, but supplies two hooks simultaneously so that both hook assemblies release the chain links simultaneously.

FIGS. 14-17shows different isometric views of the lifeboat hook arrangement1.

FIG. 14shows the hook arrangement1attached to the lifeboat2. The lowering arrangement4is via the chain link17held in a secured position within the hook arrangement1. The hook1is fixed to the lifeboat deck14through bolts.

FIG. 15shows the second part of the hook-shaped beak5bwith fixing means15aand the cylinder28connected to the underside/inside of the lifeboat deck14.

FIGS. 16aand 16bshow an isometric view of the hook, viewed from opposite sides, in a locked position. The piston arrangement31could rest on guide columns to protect the cylinder28but also to prevent unintentional hooking of the release mechanism in the locked position (not shown). A guide column could also be an integrated part of the release mechanism as shown in theFIGS. 16a,16b.

There could also be arranged a separate bow shaped device for guiding the chain link back to the hook and preventing accidents as an embodiment of the invention. This is not shown in the Figures.

FIG. 17shows the hook-shaped beak5without the release mechanism6. It shows the first safety bore22and the second safety bore mechanism16a,16b. It also shows the first guide slot7and second guide slot9. A transverse plate5cof the hook-shaped beak is fixedly connected to the lifeboat deck14. At the underside of the lifeboat deck, the second part of the hook-shaped beak is arranged. There are arranged through holes13ain the second part of the beak to connect fixing means15a-15gas shown inFIGS. 4-7to the beak5.

FIGS. 18 and 19show the actuator or piston arrangement11in further detail. The piston arrangement inFIG. 18is secured to the lifeboat through bolts.

FIGS. 20 and 21show the hook of a freefall lifeboat arrangement, viewed from the outside and the inside of the lifeboat deck14. The hook arrangement is in this embodiment of the invention attached vertical to the life boat2while in theFIGS. 14 and 15the hook arrangement is arranged horizontally on the lifeboat2.

FIGS. 22-23show the hydraulic arrangement connected to the piston arrangement.

FIG. 24shows a linear solenoid100which is another arrangement that could be arranged in connection with the piston to operate the hook. The linear solenoid is an electromechanical unit that converts electrical energy to a linear mechanical movement. The current through the winding creates a magnetic field that creates attractive force between a movable piston and a stop point.

By removing the force from the magnet, the current through the coil is eliminated and the piston moves back to the resting position. The linear solenoid100is connected to the piston through the conduits30and is preferably arranged on the lifeboat as shown inFIG. 25.

In this Figure, there are arranged two hook arrangements1on the bow and aft of the lifeboat2. As described earlier, the lifeboat2could also have only one hook arrangement1at the bow or aft of the lifeboat.

There could be other arrangements to operate the hook1, these being embodiments of the invention.

The lifeboat hook arrangement of the invention can comprise any features as described or illustrated herein, in any operative combination, each such operative combination is an embodiment of the lifeboat hook arrangement of the invention.