WO2012047112A2

WO2012047112A2 - A method, a tool and a device for coupling a load to and from a hoist line

Info

Publication number: WO2012047112A2
Application number: PCT/NO2011/000282
Authority: WO
Inventors: Bjarte Nordvik
Original assignee: Bjarte Nordvik
Priority date: 2010-10-04
Filing date: 2011-10-04
Publication date: 2012-04-12
Also published as: NO20101372A1; WO2012047112A3

Abstract

A method is described for coupling and uncoupling of a load (110/110a) to/from a hoisting line, in the form of a tool (100) that comprises a hook housing (104) and a lifting hook (108) and where the lifting hook (108) is pivot connected to an axis of rotation (107) for the hook housing (104) and the hook housing (104) comprises an accumulator the energy from which is used to pivot the lifting hook (108) back from the load-bearing position to an upper position where the load us uncoupled. The method is characterised in that the hook is held with the help of a locking body so that it cannot pivot in its lower, load-bearing position as long as an angle α° of the tool in relation to the reference angle X-X is smaller than an adjustable, set locking angle β° in relation to X-X and when α° exceeds the locking angle β° a sequence of pivoting is initiated which either starts pivot of the hook to the upper position immediately, or which holds the hook locked a given time before said pivoting starts. Also described is a tool to execute the method. Furthermore, a device is described for the mounting of a hook to a hook housing.

Description

A METHOD, A TOOL AND A DEVICE

FOR COUPLING A LOAD TO AND FROM A HOIST LINE.

The present invention relates to a method for coupling and uncoupling a load from a hoisting line in the form of a tool that comprises a hook housing and a lifting hook and where the lifting hook is rotary connected about an axis of rotation for the hook housing, and the hook housing comprises an accumulator the energy from which is used to rotate the lifting hook back from the load- bearing position to an upper position where the load is unhooked. The invention also relates to a tool as given in the introduction of claim 13 to perform the method.

Furthermore, the invention relates to a device for a tool for uncoupling and coupling a load to and from a hoisting line, wire or the like, where the tool comprises a hook housing and a lifting hook and where the lifting hook is rotary connected about an axis of rotation for the hook housing, and the hook housing comprises an actuator system set up to generate and store energy in an accumulator as a consequence of the weight of the load in combination with the crane lift, said energy is used to rotate the lifting hook back from the load- bearing position to an upper position where the load is removed.

The hook tool according to the invention is intended for all types of load handling, also for handling of loads on underwater installations, for example on the sea bed. With the invention one aims to provide a construction that is used to couple a crane hook to a load where the hook shall be rotated between two positions for coupling and uncoupling of a straddle, a wire loop or a hoisting line. Such crane hooks comprise normally a spring-loaded locking lip to close the entrance to the hook.

One also aims to provide two essential elements of such construction: 1) a construction that can delay the release of the mechanism that rotates the hook to be swung upwards to an upper position for uncoupling of the load.

2) provide a construction which in a completely new way generates the energy that is stored in the accumulator for later utilisation to turn the hook as in point 1).

There are previously known solutions where the crane hook is rotary connected about its suspension axis for coupling and uncoupling of a load. Here, references shall be made to, for example, SE-433486, DE-3938364, WO- 2005/040032, US 4,767,144, US 5,178,427, FR-2.533.635, DE-39 38 364 and JP-1209298.

A primary aim with the known solutions is to automate the coupling and uncoupling of load forks, in particular to increase the safety for the operator on a loading deck and to reduce the risk of injuries to personnel.

Several of the known solutions are based on the use of an actuator inside the hook housing charging an accumulator when the hook is connected to a shaft that runs inside a hook housing, is pulled vertically downward by the full weight of the load and not only that the hook is pivoted downward as one aims with the present invention.

In particular it is a disadvantage with the known solutions that there is no mechanism that can postpone/delay the rotation back of the hook when the load is placed on the base (a deck).

Therefore, it is an essential aim of the invention to equip the hook housing with a mechanism that can control when the above mentioned hook rotation starts after the load has been put down. It is a further aim that the mechanism ensures that the rotation itself can be carried out in a controlled way, possibly with a delay and does not immediately snap into the open position as in the known solutions. Furthermore, it is an aim that the rotation of the hook from the lower to the upper position can occur at different speeds. Furthermore, it is an aim to make the rotation back of the hook dependent of the hook being flipped or tilted over a pre-set angle in relation to a reference position (which as a rule is the normal vertical position of the hook). Another main aspect of the invention is to provide a new construction of the mechanism to provide the charging of the accumulator, and to turn the hook down to its load-bearing position.

With the present invention it is an aim to provide a locking mechanism which makes it possible to compact the hook system considerably, i.e. make it less space demanding and also increase operational safety.

Furthermore it is an aim of the invention that the accumulated energy which is supplied to the hook system in connection with the crane lift can pivot the hook with associated load about own vertical axis.

Furthermore, it is an aim of the invention to provide a construction which, in a situation where the mechanism inside the hook housing fails or becomes locked, may be set so that the hook is released from this mechanism and is pivoted manually upwards so that a load wire can be pulled out of the hook opening.

The method according to the invention is characterised in that the hook is held locked with the help of a locking body so that it is kept locked against pivoting in its lower (load-bearing) position as long as a current angle a⁰ between the longitudinal axis Y-Y of the tool and the reference position X-X of the tool is lower than a given set locking angle β° with reference in XX, and when the locking angle β° is exceeded a pivoting sequence is initiated which either immediately starts pivoting of the hook to the upper position, or which still keeps the hook locked over a given time period before said pivoting starts.

According to a preferred embodiment the pivoting of the hook is allowed when the tilt/angle a⁰ of the tool has been higher than the set locking angle β° of the mechanism continuously or accumulated over a set period. The set time is preferably from 0 up to 5 minutes, in particular 1 minute. The aim to delay the start of the pivoting cycle is that it happens that a load which has been put down on a base and the hook placed flat down on top of it, must be winched up again and be moved to another location on the base without the hook shall be uncoupled in the meantime. With the expression accumulated is meant the sum of the time periods for each such reloading where the hook has been tilted over the limit angle and that this sum is within the above mentioned time settings before the hook starts to pivot.

It is preferred to use a set locking angle β° of the order 30° - 180° and preferably 30°, as the actual angle of the tool is measured with the help of a protractor which gives a signal to the locking body to cancel the locking and start the pivotin sequence when said tilt angle setting β° is met, as the operation of the locking body is served via a control unit.

According to a preferred embodiment the hook is pivoted in a controlled manner in that braking bodies inside the hook housing brakes the pivoting of the hook to a given initial lower speed of pivoting to release the braking effect so that the hook can turn at a higher speed forward to the upper position, as the higher speed can encompass that the hook is pivoted quickly to the upper position where the wire can fall out of the hook. The hook is preferably pivoted over a sector of 135°, as the hook is pivoted over an angle of about 90° at the lower speed of pivoting and over an angle of 45o at the second speed, as the second speed can be a quick pivoting. The other preferred embodiments of the method appear in the claims 8 to 12. The tool according to the invention is characterised by a mechanism to control the hook to be held so that it cannot pivot in its lower load-bearing position as long as the angle a⁰ of the tilt between the longitudinal axis (Y-Y) of the tool and the reference position X-X of the tool is smaller than a set locking angle β° with the reference position X-X, and when the locking angle β° is exceeded a sequence of pivoting is initiated that either immediately starts pivoting the hook to the upper position, or which holds the hook locked for a given period of time before the pivoting starts.

It is preferred that a protractor is included to measure the tilt angle a⁰, said protractor is connected by signals to a locking body in the locking mechanism to keep the hook locked so that it cannot pivot. The housing can comprise a programmable control unit (130) for the setting of the actual locking angle β° in the protractor.

It is preferred that the mechanism comprises locking and braking bodies associated with an actuator which in turn is connected to the hook for the rotation of this, and the actuator is set up to be moved axially by a preloaded spring which constitutes said actuator, a nut (404) locked to the actuator so that it cannot rotate and set up to rotate a screw and the rotation of the screw and thereby the pivoting of the hook is controlled by the centrifugal brake associated with the screw, and where the indicator pushes the centrifugal brake upwardly so that it is uncoupled from the friction clutch fastened to the generator shaft.

There are preferably one or more vertical strut-formed or spring-formed position indicators set up to push the friction clutch up from the actuator and release the friction brake from the locked contact with the shaft.

It is in particular preferred that the locking body is an electric brake set up to lock the screw so that it cannot rotate, and/or a locking system comprising one or more locking balls set up to be moved out of a locking engagement with the screw and release this to be able to rotate when the tool tilts at an angle beyond the given limit β°.

The balls define a mass and their position is controlled in that the angle of attack of the force of gravity G onto the mass in the locking mechanism is changed in relation to the locking mechanism when the hook is tilted, as at a given angle the locking mechanism will cancel the described locking.

Braking bodies are preferably arranged and set up to brake the rotation of the hook to a given initial lower speed of rotation to release the braking effect so that the hook can pivot at a higher speed up to the upper position, as the higher speed can mean that the hook is pivoted quickly to the upper position where the load can be uncoupled from the hook. According to the invention a hydraulically driven actuator mechanism, where the locking of the hook in its lower position and also the upwardly swinging movement, is regulated with the help of a hydraulic cylinder that is controlled by a valve that can be operated with the help of an electric valve or mechanically when the hook is tilted. The locking body comprises weights that, under the influence of the force of gravity, hold their vertical positions until the valve is activated when the tool is tilted, to provide the opening of the valve to provide the control of the flow of fluid over the valve. Preferably, one or more vertical strut-formed or spring-formed position indicators are arranged, which push the centrifugal brake upwardly so that it is uncoupled from the clutch that is fastened to the shaft/screw.

It is particularly preferred that the rotating mechanism of the tool stands in a fluid in that the hook housing is filled by a fluid, in particular a corrosion preventing fluid, oil of glycol/antifreeze fluid, or the hook housing is filled by a gas, such as nitrogen.

The device to ensure that the hook pivots down to its load-bearing position is characterised in that the actuator system comprises a pre-tension mechanism which, in relation to the axis of pivoting of the lifting hook is eccentrically and mechanically connected through a point of pivoting of the lifting hook, and which during a downward swing movement of the lifting hook from the uncoupling position to its normal load-bearing lower position supplies energy to the accumulator.

In particular, the accumulator is a spiral spring set up, during the downward pivoting movement of the hook, to be tensioned/compressed by the pre-tension unit that comprises a shaft extending downwards under the housing part and is mounted in the point of pivoting. The shaft is preferably connected to the point of pivoting via an articulated tongue arm the end of which is fastened to a traction strut mounted in the point of pivoting.

The pre-tension unit comprises in particular an outwardly extending ring disc- formed edge that lies against the upper edge of the spiral spring, and which compresses the spiral spring against the hook housing when the hook is pivoted downwards. The pre-tension unit is further connected to a rotary mounted threaded screw mounted in the housing via a nut associated with the screw, and which is set up to be locked against the ring-formed surface in the pre-tension unit so that it cannot rotate, and the screw is connected to the locking bodies that can prevent the screw from rotating, or permit the screw to rotate, and whereby the axial movement of the pre-tension unit is converted to a rotating, screw movement via the screw/nut solution.

The threads of the screw are formed with an ascent gradient so that the nut can rotate down the screw threads in step with the pulling down of the flange surface when the hook is rotated downwards until the screw lands against said flange surface when the spiral spring is compressed. In particular, the locking body comprises a time delay unit in the form of a braking body set up to brake its rotation and thereby the screw motion of the nut and thereby the consequent rotation of the hook by the pre-tension unit so that some time will lapse from the locking body cancelling the rotation locking until the lifting hook is returned to its upper position.

According to a preferred embodiment the braking body of the locking body comprises a centrifugal brake which is connected to the screw via a gear that can set up a transmission ratio between the screw and the incoming gear shaft to an order of magnitude of about 1 :100.

The locking body comprises a gravity locking system in the form of a number of free-lying balls arranged in an abacus that does not rotate where the balls can be moved freely in the longitudinal direction of the hook system, where they either lie against an upper part of a clutch plate and provide a locking of the screw against rotation and thereby the hook from the lower to the upper position, or they are moved out of said position and release the hook for pivoting from the lower to the upper position.

The gear shaft constitutes in particular an incoming shaft in a generator which, by rotation of the screw, generates electricity to be stored in a battery, said energy can be used to rotate the hook and thereby a suspended load about the vertical axis Y-Y. The device comprises preferably a motor construction with a torque wheel fitted that can be started/stopped, for example via radio signals, as the torque wheel counter-torque is used for said rotation of the hook and its suspended load. The battery is prepared for charging by a readjustment of the hook to its upper position, where the charging takes place via the screw that is affected by the release of the accumulated energy (such as with the help of the spring), in that the generator is connected with the screw via the generator shaft and via a gear that can maintain a transmission ratio between the screw and generator of the order of about 1 :100.

The locking mechanism comprises an adjustable time delay unit so that a given time lapses from the locking mechanism cancelling the locking of the pivoting mechanism until the hook is in the upper open position, in the form of a centrifugal brake set up to function via a friction clutch, said friction clutch is set up to be disconnected from the screw/shaft when the hook is turned a given angle from below.

The centrifugal brake is set up to be disconnected from the screw/locking mechanism in that the position indicator of the pre-tension unit will lift the centrifugal brake upwards so that it is no longer engaging with the friction clutch fastened to the screw and the generator shaft, and can rotate freely with no influence from the centrifugal brake. The integrated locking lip is preferably blocked from opening the hook entrance in that its mounting to the hook is prevented from being rotated with the help of a locking device in the form of a disc set up to glide along, and close to, the arch-shaped underside edge of the housing part, whereby the bolt cannot be turned and the entrance is mechanically locked in a closed position, while when the hook 108 is rotated towards an open position it will be possible to insert the locking lip.

Finally, the device comprises a mechanism to control the locking lip from being locked out in a blocking position to be driven in as the entrance to the hook is opened between the two positions when the hook is rotated past a given angle in relation to the hook housing from the lower to the upper position, and also that the lip remains standing in an swung in position when the hook is in the upper position.

An integrated locking lip is set up to block the hook entrance when the hook is pivoted from the upper to the lower position.

The invention shall now be explained in more detail in the subsequent text with reference to the enclosed figures, in which: Figure 1 shows an application area for the hook construction according to the present invention in a crane that serves a container.

Figures 2A and 2B show hook constructions with a lifting eye, hook housing and the rotary hook in turned up position and downwardly turned position, respectively.

Figure 3 shows the same as in figure 2b, and where a tilt angle is given which the hook construction must take up for a rotation mechanism shall start to rotate the hook to the position in figure 2A.

Figure 4 shows a vertical section partly in outline through the housing and shows the inner construction in the hook housing that contributes to the hook being pivoted between the two positions, as the hook is here pivoted to the upper position as in figure 2A.

Figure 5 shows the corresponding to figure 4, where the hook is turned to its lower position (figure 2B).

Figure 6 shows an enlarged section of the construction inside the housing.

Figure 7 shows the situation where the drive mechanism in in a tensed-up position where the tool/hook is tilted (in a position Y-Y) at an angle a of about 100 degrees in relation to the reference angle X-X. Where free-lying balls 308 are not in contact with the top of the centrifugal brake. Where the angle of attack of the force of gravity in relation to the locking mechanism has such a direction that a movable mass in the form of the balls in the locking mechanism is changed so that the balls move out of the locking position.

Figure 7a shows a plane section of the top plate of the centrifugal brake with the adapted concave recesses for the free-lying balls 308 to regulate the end of the locking of the shafts. By changing a number of balls one will be able to change the locking angle β° in relation to the reference angle X-X, by reducing the number of balls the locking angle β° will be smaller. Figure 8 shows an enlarged picture of the centrifugal brake construction with associated abacus and free-lying balls where the balls are pulled back in the abacus.

Figure 9 shows the setting of the inner drive and locking mechanism for the operation (rotation) of the hook, as the drive mechanism inside the housing is in a position of rest with turned in locking lip.

Figure 10 shows the setting of the inner drive and locking mechanism for the operation (rotation) of the hook, as the drive mechanism inside the housing is in a position of rest with turned out locking lip

Figure 11 shows the construction details for how the locking lip is driven in as a consequence of the pivoting of the hook. Figure 12 shows a variant of the hydraulically locked drive mechanism with a valve control for the flow of hydraulic fluid between the chambers when the hook 108 is pivoted about 107.

Figure 13 shows the hook tilted so that the locking mechanism in the form of a valve is driven in open position in that the hook angle Y-Y is greater that an angle β in relation to the reference angle X-X.

Initially, reference is made to figure 1 which shows a crane 145 with a boom 102 and which carries a load 110 via a hoisting wire 115 connected to a wire snood (Norwegian: forloper) 125 the end of which is fastened to the hook 108 associated with the crane hook construction 100. The load 110 is suspended in the crane hook structure 100 from its hook 100 according to the invention. According to the example the load is a container which is suspended from a hook 108 via a straddle unit (Norwegian: skrev) or a number of lines/wires fastened to each corner of the container.

The present invention relates to this crank hook construction 100, as will be clear from the following text. The construction 100 is, as shown in the figures 2A and 2B composed of a hook housing 104, an upper lifting eye unit 105 to be hooked onto the wire snood 125 from the crane and the hook 108 itself which is rotary about a rotatory bolt 107 at the bottom of the hook housing. The hook housing 104 is fastened to the wire snood via the lifting eye 105 and the locking nut 106 that carries the load. The hook housing 104 with the hook 108 is set up to be rotated about its longitudinal axis Y-Y (figure 2A) through the tool. This rotation takes place by driving a torque wheel 201 that sets up a counter torque which leads to a rotation of the hook with the suspended load about the axis Y- Y.

The hook 108 is rotary connected to the lower part of the hook housing 104 via the rotation bolt 107 (the axis of rotation) so that the hook can be led between the two extreme positions, an upper position where an entrance 109 of the hook is opened and the load wire loop can be uncoupled, and the lower position where the hook 108 carries the load 110. As shown the hook comprises a locking lip 604 which is rotary about a separate rotation bolt 603 between to close (figure 2) the entrance 109 (figure 3) in the load-hanging position, and to open the entrance (figure 3) when the load shall be uncoupled. When the tool is in the position in figure 2A, and the locking lip 604 is inserted, the wire hook 110 falls out by its own weight. The locking lip 604 is spring loaded and blocks the entrance 109 in its normal position, but can be forced to be flipped into an adapted slit in the hook body 108.

Figure 3 shows the adjustable locking angle β° which constitutes the limit for when the locking of the hook rotation (see later in this description) shall cease. The angle β° is according to an example of the order of 30° -180° and it is preferably 30° if the reference angle X-x is set to 0. In figure 3, this corresponds to about 30°. The limit for locking is shown as a cone with the point directed downwardly, and as long as the hook with its tilted length (the axis Y-Y) is in an actual tilted position and placed inside the space that defines the cone, the locking will be maintained. When the hook is lowered the eye of the load 110 will hang down and the hook will start to rotate when the eye of the load hits the upper part of the eye of the hook at the point 2000 (the point of the cone) as shown in figure 3. When the hook is tilted beyond this angle, i.e. outside the cone, the sequence of rotation starts which constitutes the invention according to the subsequent claim 1 , cf. figure 7 which shows that the longitudinal axis Y- Y forms an angle of about 100 degrees if the reference angle X-X is set to 0, which then lies outside the locking angle β°.

As shown in the figures 4, 5 and 6 the hook housing comprises a mechanism to generate energy that can be used to pivot the hook between the two positions, and this can be divided into three constructive parts which are mutually connected.

1) The above mentioned actuator mechanism to form energy in an accumulator to be used later to rotate the hook about the shaft 107 according to the subsequent claim 23.

2) Devices to both lock and then delay the start of the return pivoting of the hook, and to control the speed from the start to pivot from a lower, closed position until it reaches an upper open position (claims 1 and 13)

3) Devices to cancel the locking of the hook in the lower position when the hook housing is tilted beyond the pre-set angle in relation to a reference angle (start angle) that can be the vertical (load-bearing) position (claims 1 and 13).

Furthermore, the construction comprises (at the bottom in figure 4) a set of articulated arms that connect the hook with the actuator mechanism, and a release mechanism which makes possible manual pivoting of the hook and opening of the inlet lip if malfunctions arise.

The construction inside the hook housing for the two hook positions are illustrated in the figures 4 and 5. Mechanism to generate and store energy in the hook housing to be used later to pivot the hook (cf. claim 23).

The pivoting mechanism to swing the hook about the rotation bolt 107 is arranged inside the hook housing 104 is preferably in a circular-cylindrical form. The lower end of a traction strut 512 extends out from the bottom 514 of the housing and is connected with the hook 108 mounted below. The traction strut 512 constitutes the lower part of an upward open, sleeve formed housing part which hereafter shall be designated an actuator 500 that is fitted inside the housing 104. According to an essential feature of the invention, the lower part of the tractions strut 512 is mounted to the side of the axis of rotation 508. When the traction strut of the actuator is pulled up and into the housing, the hook 108 pivots about the axis 107 upwards into its upper position, while when it is pushed downwards, the hook is rotated correspondingly down to its load- bearing position. The actuator 500 which functions as a pre-tension body is set up to charge an accumulator 504 with energy when the hook pivots downwards and carries a load, said energy is later used to pivot the hook upwards again as explained above and in the following. In this case the accumulator is a compressing driving spiral spring 504 the lower end of which rests against a seat 513 at the bottom of the housing 104.

At the top, the actuator 500 comprises one or more vertical strut-formed or spring-formed position indicators 520 that extend upwards through guiding channels in the housing framework, and which end up just below the underside of a friction clutch 306. They are set up to lift the centrifugal brake 305 when the actuator is pushed up by the spring and release the centrifugal brake from a locking engagement with the friction clutch 306 that is fastened to the shaft 303 as will be explained later in the description. According to the invention the indicator can comprise one or more springs, or a spiral spring that can internally accommodate the mechanism.

The actuator 500, cf. also figure 6, is placed coaxially inside the hollow space 504 in the spiral spring, and the upper part of the actuator 500 comprises an outwardly extending circular flange 514 (a hooklike shape) the underside of which rests on top of the drive spiral spring 504. When the hook 108 carries a weight, the bolt 107 is pivoted from its upper position in figure 4 to its lower position in figure 5 and pulls down the tractions strut 512 and the spring 504 is compressed under the flange 514. Consequently, the spring functions as accumulator that stores energy.

The movement of the actuator 500 is set up, via a rotary screw 403, to be controlled by a brake system in the housing to influence both when the hook (for example after a time delay) shall start the return pivoting after the load has been uncoupled, and how fast this return pivoting shall be.

The principle that is utilised in the construction in the present invention is that the linear movement of the actuator 500 is converted into a rotary movement by the screw 403 via a nut 404 as will be explained later in this description.

The nut 404 is fitted into the lower end of the screw 404 with correspondingly formed threads. The upper end of the screw 403 is fastened in a gearbox 400 so that it cannot rotate and which is fitted in a gear holder 401 which is secured to the hook housing 104. The screw is defined as the out-going shaft 403 from the gearbox 400, while the in-going, rotary shaft 303 is a generator shaft with a friction clutch 306 fixed on to it. The generator shaft 303 runs upwards and is set up to drive a generator 301 to generate electricity which is then stored in a battery or battery-pack 130 (shown schematically only) uppermost in the hook housing. This electricity can be used to connect and disconnect the locking body that prevents the screw from rotation, to drive the torque wheel 201 to rotate the whole of the hook/load about the axis Y-Y, and also to operate the control system (120,130) and electric brake 302.

The generator shaft 303 is further connected to an electric brake 302 that can prevent the generator shaft from rotating.

The gear is set up to give a transmission of 1 :100 from the out-going shaft 403 to the ingoing-shaft 303. This means that when the screw 403 rotates one turns the gear 400 rotates its ingoing shaft 100 times. This is also the case for the torque where the ratio is that the incoming shaft 303 of the gear 400 is burdened with 1/100 less torque than what the screw as the outgoing shaft 403 brings upon the gear 400. The gearbox can, of course, be set at other transmission ratios than 1 :100. The ingoing shaft/generator shaft 303 that drives the generator 301 , is set up to be coupled to mechanisms or bodies that can completely lock the shaft 303 and the screw 403 from rotating, and furthermore control the speed of the shaft when it is permitted to rotate when the braking stops.

Description of braking bodies and their coupling to the screw/transmission shaft.

In the system according to the invention there are two blocking systems that can prevent rotation, namely an electric blocking system and a mechanical blocking system.

Electrically driven blocking system.

The electric brake 302 comprises an electrically controlled braking body 302 which is fitted to the hook housing 104 and set up to block the generator shafts 303 from rotating when the electrical brake is without voltage and can comprise a locking bolt, or a friction operating blocking organ. This will further prevent the gear wheels inside the gear 400 and thereby the screw 403 to rotate and prevent the hook 108 from being rotated from its lower to its upper position. When a voltage (current) is supplied to the electric brake 302 it will uncouple the generator shaft 303 so that both the gear 400 and the screw 403 can rotate, something which ensures that the hook 108 can pivot about the pivoting bolt 107 from the lower to the upper position. The electric brake 302 is set up to be remotely controlled by radio signals from the crane driver or directly operated by the system built into the hook housing, which comprises an angle indicator 120 with a control card for time delays driven by electricity from the battery (the battery pack). The angle indicator registers the tilt angle Y-Y which the tool forms in its inclined position with the reference line (the vertical) X-X and compares it to the pre-set reference angle β°·

When the hook Y-Y tilts more than °the angle indicator 120 gives a signal to a control card which further opens for supplying electricity to the electric brake 302 which in turn releases the generator shaft 303 for free rotation. The hook 108 can thereby pivot to an open position. A control unit 120 is a programmable unit where the wanted reference angle can be set by the operator.

The system described under the electrical brake will be able to operate independently or in combination with the fully mechanical solution based on centrifugal brakes and locking balls as described below.

Centrifugal brake.

The hook housing comprises a centrifugal brake 305 for the purpose of regulating the pivoting/opening speed of the hook 108. One wishes to provide, for example, that the hook is initially pivoted slowly, and quickly at the end of the pivoting.

The centrifugal brake 305 is free to rotate about the same axis as the gear 400, and when the hook 08 is in its lower position the centrifugal brake 305 can be locked to the gear 400 so that it cannot rotate, by means of the coupling designated as a friction clutch 306. The friction clutch 306 is secured to the shaft/generator shaft 303 so that it cannot rotate. Furthermore, there are concave hollow spaces 308 scored out at the top the disc form of the centrifugal brake, see figures 7 and 8, which are adapted to opposite lying balls 307. A frame secured against rotation (called an abacus) 304 is arranged at a distance above the centrifugal brake/balls with vertical recesses 309, each of which can hold one of said balls 307. When the tool is tilted above a locking angle β° the balls will move up in the abacus 304 and allow the centrifugal brake 305 to rotate.

These balls will prevent the centrifugal brake 305 to rotate when the tool/hook housing is vertical or has a tilt angle Y-Y smaller that the set locking angle β°, as they then push against the overlying, housing secured, non-rotating abacus 304. When the hook housing 104 is tilted the balls 307 will, at a given angle of inclination be pressed/fall out of the described concave hollow space 308 and recesses and into said borings 309 so that the centrifugal brake 305 is permitted to rotate. This solution falls under the definition where the angle of attack of the centre of gravity onto a movable mass/the balls in the locking mechanism are changed in relation to the locking mechanism when the hook is tilted. So that at a given angle the locking mechanism will cancel the described locking of the shaft so that it can rotate.

Here, reference is made to the figures 7-8, which show the hook housing tilted at an angle a of about 100° where the balls fall out of the recesses 308 and into the borings 309 in the abacus 304.

When the hook is pivoted from the lower to the upper position above an angle sector of about 135° the centrifugal force 305 will be disconnected from 306 friction clutch and the screw when the hook 108 has pivoted about the pivot bolt 107 by, for example, 2/3 (90°) of the total pivoting of about 135°.

The aim of the centrifugal brake 305 is to regulate the rotational speed of the screw 403 via the gear 400.

This effect is due to the speed of rotation of the centrifugal brake 305 being controlled via a brake system 305a which, due to the centripetal force will be pushed outwards and brakes against, for example, 104 the hook housing, something that means the rotation of the screw is reduced to a lower, balanced level.

When the hook 108 is rotated by about 2/3 of the total rotation (for example 90° of the total rotation) in that the actuator 300/traction strut 512 is forced up into the hook housing, the circular flange 514 will abut and push the position indicator 520 upwards towards the plate 305c which in turn will push the centrifugal brake 305 upwards in the hook housing 104. The centrifugal brake will thereby be released from the locking contact with the shaft 303. This means that the friction clutch 306, and thus the gear 400, gets to rotate freely without any braking from the centrifugal brake 305. The speed of rotation of the gear 400 and thus the screw 403 will increase and the hook 108 will pivot faster about the rotation bolt 107 the last 45° (the higher speed).

The solution described can be combined with the electrical brake 302 and the generator or appear as an independent, mechanical solution.

The coupling between actuator and screw/braking mechanisms. As mentioned above, the linear movement of the actuator 500 is converted to a rotating screw movement via a nut 404. The screw, the outgoing shaft 403 extend downwards under the gearbox 400 and co-axially into the hollow space inside the actuator 500/the spring 403.

Inside the hollow space of the actuator a ring-formed construction surface/flange 502 extends and defines a tapered opening/hole which the screw 403 freely passes through. The nut 404 is screwed onto the screw and the screw 403 with the associated nut 404 is formed with threads with a pitch of typically P=5, i.e. which is defined so that when the nut 404 and the screw 303 have rotated one turn in relation to each other, there has been a mutual displacement in the longitudinal direction between the screw and the nut of 5 mm. A such incline ratio leads to that when the screw, i.e. the tool, is set vertically, the nut 404 will screw itself downwards because of its own weight until it lies on the top surface of 502 of the flange. The nut 404 can be pushed downwards with the help of a spring 405 (for example a spiral spring) that can be inserted between the bottom plate of the gearbox 400 and the top surface of the nut 404 so that the spring can provide a pushing force onto the nut and promote its rotation on the screw threads when the actuator 500 is pulled downwards under the nut.

However, the nut 404 is locked so that it cannot rotate (friction connected) to the flange surface 502, i.e. that when it lies against the surface it cannot rotate when the actuator presses upwards. When the actuator 500 then is forced upwards from below by the spring 504, the fixed nut 404 will force the screw 403 to rotate instead, something which is made possible by the high pitch/incline ratio of the threads. But it requires that the previously described locking and braking bodies further up in the housing have releases the screw so that it can rotate. The coupling of the actuator to the hook (claim 23)

As mentioned above the lower end of the traction strut 512 of the actuator 500 is fitted to the hook housing at a mounting point 510b lying a distance A from the axis of rotation 107, i.e. that the hook will now pivot up and down, at the same side of the rotating bolt/axis 107 as the location of the mounting point 510b.

When the traction strut 512 of the actuator 500 is pulled up and into the housing, the hook 108 is turned about the shaft 107 upwards to its upper position, while when it is pushed downwards the hook is turned correspondingly downwards to its load-bearing position. As the mounting point 107 of the hook is on the axis y-y, the traction strut will preferably have an arch shape down to the mounting point 510b, or be formed by a set of articulated arms that connect the traction strut 512 with the mounting point 510b as will be explained in the following, and with reference to figures 4 and 5.

The set of articulated arms is formed so that this construction can be used at the same time to release the hook movements from the position of the actuator 500 if this is locked in a wrong position as a consequence of a breakdown inside the hook housing. In a such fatal situation it is an aim that the hook shall be able to be released manually, be turned upwards and be released from the load wire that is pulled out of the hook opening 109, so that the hook housing can be sent for maintenance and repair. According to a preferred embodiment, the mid-point of a torque arm 508 is rotary mounted at the end of the traction strut 512 via a rotating bolt 508. The upper end of a traction strut 510 is rotary mounted at the one end of the torque arm 507. The lower end of the traction strut 510 is in turn mounted in the traction point 510b.

The other end of the torque arm 506 is shaped with a gliding element or gliding wheel 506a set up to be mounted in a seat 701 b at the top of an extended rod- formed locking lip releaser 702 which in turn is mounted in the hook housing metal 104 at the rotating point 703. In those cases where one gets a faulty function in the hook housing mechanism, and the hook 108 will not rotate upwards, a load 110/110a must be uncoupled manually from the automatic crane hook. This is done in that one manually grips around the top of the release 701 and flips this about the rotating point 703. This leads to the torque arm 507 being released completely so that it can freely swing down and the hook 108 can be rotated manually about the rotating bolt 107 and the load wire can be uncoupled from the hook, cf. figure 12.

The lower end of the locking lip release 701 comprises an inwardly extending shoulder section 701a set up to affect a rotary carrier 601 which is mounted in the rotating axis/rotating bolt 107. The one end comprises a boss-form 604a that can work with a boss 604a associated with the locking lip 604. The other end comprises an extended shoulder/arm 601 b that can lie against the ledge/shoulder section 701a at the lower end of the extended locking lip release 701. This mechanism has as an aim to control the movement of the locking lip 604 when the hook shall be pivoted.

When the drive mechanism in the form of an actuator 500 is pushed upwards, the articulated connection down to the rotating bolt 511a will pivot the hook 108 about the pivoting bolt 107. With a given pivoting the shoulder 601b on the rotary carrier 601 will hit the shoulder 701a of the locking lip release 701. When the shoulder 601b lies against the shoulder 701a, the rotary carrier 601 will not be able to rotate any more. This leads to the boss 601a going towards the boss 604a and for any further rotation of the hook 108 the spring-loaded locking lip 604 will be driven/pushed in and the entrance 109 of the hook 108 will be opened, cf. fig 3.

By operating the locking lip release in the form of instead of pushing in the upper part of the lip release 701 the shoulder 701a will be rotated out and the rotary carrier 610 will be able to rotate so that the pre-stressed spring-loaded locking lip 604 again will close the entrance 109 of the hook 108, see figure 4.

Liquid-filled housing

To avoid that the mechanism is subjected to different environments such as water, which could freeze to ice in given circumstances and prevent the mechanism to function, the hook housing can be a completely watertight construction which is filled with a component protecting fluid, such as a liquid or a gas. It can be an anti-corrosion fluid, oil or glycol/anti-freeze fluid. A typical gas can be nitrogen. In a such solution a lower piston sealing or piston seal 160 is arranged in the bottom of the hook housing which allows the traction strut to move up and down with any leaks occurring. One can thereby ensure the function independent of the surrounding temperatures.

An upper seal 150 is arranged in the upper part of the hook housing (cf. figure 5), as the filling of fluid in the hook housing takes place via a filling pipe piece through an elastic pressure compensating bellows or overpressure valve in the hook housing shown by 170. For the use subsea, the hook housing is set up with a moveable bellows to compensate for pressure differences between the inner of the hook housing and the external environment, i.e. that the chamber is internally experiencing approximately the same pressure as the external water pressure. This solution provides that one does not need to design the equipment for external pressures, something that reduces the complexity, weight and price.

A function description:

When the actuator 500 is pulled downwards in that the hook 108 is pivoted down from the upper to the lower, load-bearing position, the spring is compressed and the nut 404 turns accordingly in that it rotates down the threads of the screw 403 at the same speed as the surface of the shoulder 502 is pulled down. The nut 404 can also be driven downwards with the help of the spring 405 which is preferably a spiral spring. The nut 404 will rotate downwards until it meets the ledge surface 502 which is an internal ledge in the drive-mechanism housing 500.

When the load is removed from the hook 108 the drive spring 504 will force the actuator 500 upwards. The actuator 500 will hit the underside of the nut 404, cf . the ledge surface 502. Because of the friction between the underside of the nut 404 and the tapering of the actuator 500, the nut 404 cannot rotate.

The linear force of the actuator 500 is thereby transferred to the nut 404 which is rotational locked to the actuator 500 through (via) the ledge surface 502. The linear force the nut sets up is therefore transferred to the screw 403. Due to the relatively high pitch incline (for example P=5) the screw 403 will set up a rotating torque on the threaded connection between the screw 403 and the nut 404. This torque is transferred to the outgoing shaft/underside of the screw 403 as a consequence of the coupling that cannot rotate. Hydraulic solution

As an alternative to the above mentioned construction, a hydraulically driven mechanism can also be used, where one can lock the hook in its lower position and also regulate the upwardly pivoting movement of the hook with the help of a hydraulically driven cylinder that is controlled by a valve which can be operated with the help of an electric valve or mechanism when the hook is tilted. This solution is illustrated in the figures 12 and 13, and these figures are referred to. The hook is omitted in figure 13 for reasons of clarity.

The solution is in the main based on that the inner housing is divided into two chambers, chamber A and chamber B and that a hydraulic fluid is made to flow between these via a valve element. It is based on that one isolates/lock the hydraulic fluid inside a chamber B - 1012 when the hook is in the load-carrying position, figure 13. For the hook to be able to be uncoupled from the load, the chamber B 1012 must evacuate the fluid so that the actuator 1011 with the cylinder can move upwards in the hook housing 104 and pull the traction strut 512 upwards.

A piston 1007 is fastened to the hook housing as it is fitted a piston 1009 with a sealing ring that prevents the fluid from leaking out in an uncontrolled fashion. When the hook 108 is pulled down the actuator 1011 with the cylinder will be pulled at the same time and the drive spring 504 will be under tension. The fluid will then flow from the chamber A - 1002 through a check valve 1008 and down into the chamber B - 1012. Then the load is removed from the hook 108 the spring 504 will force the actuator 1011 with the cylinder upwards. This will then lead to that the pressure in the chamber B - 1012 increases and the check valve 1008 will not let fluid from chamber B into chamber A. If the valve 1003 is closed the actuator 1011 with the cylinder will thereby be hydraulically locked in its lower position. When the valve 1003 is opened the fluid will be able to flow from chamber B to chamber A and it will be possible to open the hook 108 again. The valve 1003 is either electrically or mechanically operated. In a mechanical solution it can be operated in that the hook is tilted, as is shown in figure 13 (approximately 80°), so that the weight 1005 changes its angle in relation to the locking mechanism lies as this leads to that the valve of the torque arm 1005 changes angle in relation to the valve 1003. The weight 1006 functions analogue to the locking balls mentioned in the previous solution, a locking system comprising the balls which the moveable mass are set up to influence an element to enter into a locking engagement with the screw and release this to be able to pivot when the tool sits at an angle which is above the given limit of β°.

This angle change opens the valve and permits the flow of fluid again, as a such type of valve is well known.

When the hook is hoisted again, the weight will again take up the vertical position under the influence of the force of gravity. The valve 1003 will then take up a closed position and the cycle can be repeated. When the hook moves from the lower to the upper position about 135 degrees a throttling of the amount of flow will regulate the speed of the hook the first about 90 degrees. A typical time here will be about 10 seconds. When the hook 108 has passed through 90 degrees on its way from the lower to the upper position the sealing ring of the piston will pass the boring/cut out 1010 for the sealing, and this will lead to that one gets a fast ventilation of the remaining fluid in the chamber B (1012). This will further lead to that the hook 108 will open faster the last 45 degrees of the pivoting.

With the use of electrical control the valve 1003 will normally be closed when no voltage is applied, while when voltage is applied it will open so that fluid can flow from the chamber B to the chamber A. For a non-electric solution the valve is controlled via radio by the crane driver, or is directly operated by the built-in system in the hook housing, which comprises a protractor with a control card for time delays driven by batteries. Figure 13 (without the hook being shown) shows the tool according to this version tilted at an angle close to 80 degrees. The notation X-X is the reference angle that the locking mechanism is set at, normally it will be vertical and set to 0°, a⁰ is the real angle the hook Y-Y has with respect to X-X. β° is a locking angle with respect to X-X which the locking mechanisms is set at and this angle can be adjustable. The limit angle β° comprises the whole circumference of X-X as shown in fig 3. When the angle a⁰ is less than a locking angle β° with respect to X-X the locking mechanism will lock the hook in its lower load- carrying position. When the angle a⁰ is greater than a locking angle β° the locking mechanism will start the pivoting cycle and release the locking of the hook in a load-carrying position. This cone housing-formed illustration of the limit angle for the unlocking is also shown in figure 12.

Claims

P A T E N T C L A I M S

1. Method for coupling and uncoupling of a load (110/110a) to a hoisting line, in the form of a tool (100) which comprises a hook housing (104) and a lifting hook (108) and where the lifting hook (108) is pivot connected about an axis of rotation (107) to the hook housing (104), and the hook housing (104) comprises an accumulator the energy from which is used to pivot the lifting hook (104) back from the load-bearing position to an upper position where the load is uncoupled, characterised in that the hook is held with the help of a locking body so that it cannot rotate in its lower, load-bearing position as long as a present angle a⁰ between the longitudinal axis Y-Y of the tool and the reference position X-X of the tool is smaller than an adjustable locking angle β°, and when the locking angle β° is exceeded by a⁰ a sequence of pivoting is initiated which either starts pivoting of the hook to the upper position immediately, or which holds the hook locked a given time before said rotation starts.

2. Method according to claim 1 , characterised in that the hook is allowed to rotate when the tilt/angle a⁰ of the tool has been larger than the set locking angle β° of the mechanism continuously or accumulated over a given time.

3. Method according to claim 2, characterised in that the set time is from 0 to 5 minutes, particularly up to 1 minute.

4. Method according to claims 1-3, characterised in that a locking angle β° set at 30° - 180° is used, with it preferably being 30°, as the relevant angle of the tool is measured with the help of a protractor (120) which gives a signal to the locking body (302) to cancel the locking and start the pivoting sequence when said tilt angle setting β° has been reached, as the operation of the locking body is regulated by a control unit (130).

5. Method according to claims 1-4, characterised in that the hook is pivoted in a controlled way in that the braking bodies in the hook housing brakes the hook pivoting to a given initial lower speed of pivoting to release the brake effect so that the hook can pivot at a higher speed up to the upper position, as the higher speed can mean that the hook is pivoted immediately to the upper position where the wire can fall out of the hook.

6. Method according to claim, characterised in that the hook is pivoted through a sector of 135°, as the hook is about 90° at the lower pivot speed and through an angle of 45° at the other speed which can be said immediate pivoting.

7. Method according to claim, characterised in that the hook is pivoted by an axial movement of an associated actuator of a wound-up spring under tension, said force being converted to a rotating movement by a screw (403), where the screw is locked by a releasable locking body, and the rotation of the screw (403) and thus the pivoting of the hook is slowed down and controlled by the application of a centrifugal brake connected to the screw via a friction clutch.

8. Method according to claim, characterised in that the screw is disconnected from the centrifugal brake with the help of one or more vertical rod-formed or spring-formed position indicators (520) that push up the centrifugal brake unit 306 and releases this from locking contact with the clutch (306) fastened to the shaft 303.

9. Method according to claim 1 , characterised in that the mechanism that locks the hook in a load-bearing position is controlled in that the angle of attack of the force of gravity G on a movable mass (308,1006) in the locking mechanism is changed in relation to the locking mechanism when the hook is tilted, as when a given angle is reached the locking mechanism will cancel the described locking.

10. Method according to one of the preceding claims, characterised in that the applied locking body is an electric brake and/or a locking system comprising a movable mass in the form of one or more locking balls (308) set up to disengage from the locking position with the screw and release this so that is can be rotated when the tool tilts at an angle greater that the given limit of β°.

11. Method according to claims 1-10, characterised in that the locking and the pivoting take place by the application of a hydraulically locked mechanism, where the hook is locked in its lower position and also that the upwardly swinging movement is regulated with the help of a hydraulically driven cylinder that is controlled by a valve that can be operated with the help of an electric valve or mechanically when the hook is tilted.

12. Method according to claim 10, characterised in that the opening of the valve to provide a fluid flow over the valve is controlled by a locking body in the form of a weight 1006 (as the actual mass) which under the influence of the force of gravity holds its vertical position to the valve is activated when the tool is tilted.

13. Tool for coupling and uncoupling of a load (110/110a) to and from a hoisting line, in the form of a tool (100) which comprises a hook housing (104) and a lifting hook (108) and where the lifting hook (108) is pivotable connected about an axis of rotation (107) for a hook housing (104) and the hook housing (104) comprises an accumulator set up to store energy, said energy is used via an actuator to pivot the lifting hook (108) back from the load-bearing position to an upper position where the load is uncoupled, characterised by

a mechanism to control the hook to be held so that it cannot pivot in its lower load-bearing position as long as a relevant angle a⁰ between the longitudinal axis (Y-Y) of the tool and the reference position (X-X) of the tool is smaller than an adjustable locking angle β° in relation to the reference angle X- X, and when the locking angle β° is exceeded by the tilt angle a⁰ a sequence of rotation is initiated which either immediately start pivoting of the hook to the upper position, or which holds the hook locked a given time period before the pivoting starts.

14. Tool according to one of claim 13, characterised by a protractor (120) to measure the tilt angle a⁰ in relation to X-X, said protractor (120) is connected by a signal to a locking body (302) in the locking mechanism to hold the hook locked so that it cannot pivot when the angle a⁰ is smaller than a locking angle β°, but permits said pivoting when the tilt angle a⁰ becomes larger than the locking angle β°.

15. Tool according to one of the claims 13-14, characterised in that the housing comprises a programmable control unit (130) for the setting of an actual locking angle β° in the protractor.

16. Tool according to one of the claims 13-15, characterised in that the mechanism comprises

locking and breaking bodies associated with an actuator which in turn is connected to the hook for the pivoting of the hook, and the actuator is set up to be moved axially by a wound-up spring that makes up said actuator,

a nut (404) locked so that it cannot rotate to the actuator and set up to rotate a screw (403), and

the rotation of the screw (403), and thereby the pivoting of the hook, is controlled by a centrifugal brake connected to the screw/generator axis which can be disconnected by a friction clutch.

17. Tool according to one of the claims 13-16, characterised in that one or more vertical rod-formed or spring-formed position indicators 520 are set up to push the friction clutch 306 upwards by the actuator and release the friction brake from locking contact with the shaft 303.

18. Tool according to claims 13-17, characterised in that the locking body is an electrical brake set up to lock the screw so that it cannot rotate, and/or

a locking system comprising one or more locking balls set up to be moved out of a locking engagement with the screw and release this so that it can be rotated when the tool tilts at an angle a⁰ that is greater than the given limit β°.

19. Tool according to claims 13-18, characterised in that breaking bodies are set up to brake the hook rotation to a given, initially lower speed of pivoting to release the braking effect so that the hook can pivot at a higher speed up to the upper position, as the higher speed can include that the hook pivots immediately to the upper position where the load can be released from the hook.

20. Tool according to claims 13-19, characterised in that a hydraulically driven actuator mechanism, where the locking of the hook in its lower position, and also the upward movement are regulated with the help of a hydraulic cylinder that is controlled by a valve that can be operated with the help of an electric valve or mechanically when the hook is tilted.

21. Tool according to claims 13-20, characterised in that a locking body in the form of the angle of attack of the force of gravity on a moveable mass in the locking mechanism, is changed in relation to the locking mechanism when the hook is tilted. So that at a given angle, the locking mechanisms will cancel the described locking by providing the opening of the valve to provide the controls of the fluid flow over the valve.

22. Tool according to claims 13-21 , characterised in that the screw is disconnected from the centrifugal brake with the help of one or more vertical rod-formed or spring formed position indicators 520 that push up the friction clutch 306 and releases this from the locking contact with the shaft/screw 303.

23. Tool according to claims 13-22, characterised in that the pivoting mechanism is accomodated in a fluid in that the hook housing (104) is filled by a liquid, in particular an corrosion preventing liquid, oil or glycol liquid, or the hook housing is filled by a gas, such as nitrogen.

24. Device for a tool (100) for coupling and uncoupling of a load (110/100a) to and from a hoisting line, where the tool (100) comprises a hook housing

(1049 and a lifting hook (108) and where the lifting hook (108) is pivotable connected about a axis of rotation (107) for the hook housing (104), and the hook housing (104) comprises an actuator system set up the generate and store energy in an accumulator as a consequence of the weight of the load in combination with the crane lift, said energy is used to rotate the lifting hook (108) back from the load-bearing position to an upper position where the load is coupled off, characterised in that the actuator system comprises a pre-tension mechanism which in relation to the axis of pivoting (107) of the lifting hook, is eccentrically and mechanically connected through a point of rotation (511) of the lifting hook (108), and which during a downward pivoting movement of the lifting hook (108) from the uncoupling position to its normal load-bearing lower position supplies energy to the accumulator.

25. Device according to claim 24, characterised in that the accumulator is a spiral spring (405) set up to, during the downward pivoting movement of the hook, be tightened/compressed by the pre-tension unit (500) which comprises a shaft (512) extends downward during the housing part and is mounted in the point of rotation (511)

26. Device according to claims 24-25, characterised in that the shaft (512) is connected to the point of pivoting (11) via an articulated torqued arm (507) the end of which is fastened to a tension strut (/510) mounted in the point of pivoting (511).

27. Device according to claims 24-26, characterised in that the pre-tension unit (500) comprises an outwardly extending ring joint edge (51) that lies against the upper edge of the spiral spring (504), and which compresses the spiral spring (504) against the hook housing (104) when the hook is pivoted downwards.

28. Device according to one of the preceding claims 24-26, characterised in that the pre-tension unit (500) is connected with a threaded screw (403) rotary mounted in the housing via a nut (404) associated with a screw, and which is arranged to be locked so that is cannot rotated against a ring-formed surface (502) in the pre-tension unit (500), and the screw is connected to locking bodies that can prevent the screw (403) from rotating, or permit the screw (403) to rotate, and whereby the axial movements of the pre-tension unit is made into a rotating screw movement via the screw/nut embodiment.

29. Device according to claim 28, characterised in that the threads of the screw (403) are formed with a pitch such that the nut 404 can turn downwards in the screw threads in step pulling downwards of the recess shoulder 502 when the hook (108) is pivoted downwards until the screw lands against said recess surface (502) when the hook is in its lower load-bearing position.

30. Device according to claims 24-29, characterised in that the locking body comprises a time-delay unit in the form of a braking body set up to brake its rotation and hence the subsequent pivoting of the hook (108) by the pretension unit so that a given time lapses from the locking body cancelling the locking of the pivoting and the lifting hook is returned to its upper position.

31. Device according to one of the preceding claims 24-30, characterised in that the braking body of the locking body comprises a centrifugal brake (305) which is connected to the screw (403) via a gear (400) that can set up a transmission ratio between the screw (403) and an inward running gear shaft (303) of the order of about 1 : 100.

32. Device according to one of the preceding claims 24-31 , characterised in that the locking body comprises a gravity-locking system in the form of a number of free-lying balls (308) arranged in a rotation fixed abacus (304), where the balls can move freely in the longitudinal direction of the hook system where they either lie against the upper part of a clutch plate and provide a locking against rotation for the screw (403) and thereby for the hook (108) from a lower to an upper position, or they are moved out of said position and release the hook ( 08) for pivoting from the lower to the upper position.

33. Device according to one of the preceding claims 24-32, characterised in that the gear shaft constitutes an inward running shaft (303) in a generator which, by rotation of the screw (403), generates electricity for storing in a battery (130), said energy can be used to pivot the hook and thereby a suspended load about the vertical axis X-X, and also for the operation of the control system (120,130) of electric brakes.

34. Device according to one of claims 23-32, characterised in that the motor construction (202) with a connected torque wheel (201) which can be started and stopped, for example via radio signals, as the counter-torque of the torque wheel (201) is used to said pivoting of the hook and its suspended load (110).

35. Device according to one of the preceding claims 24-34, characterised in that the battery that is brought to charging at the hook readjustment to the upper position, where the charging takes place via the screw (403) that is influenced by the release of the accumulated energy (such as with the help of the spring), in that the generator (301) is connected to a screw (403) via the generator shaft (303) and via a gear (400) that can set up a transmission ration between the screw (403) and the generator (301) of the order around 1 :100.

36. Device according to one of the preceding claims 24-35, characterised in that the locking mechanism comprises an adjustable time delay unit such that it takes a given time from the locking mechanism cancels the locking of the rotation mechanism until the hook is in the upper, open position, in the form of a centrifugal brake 305 set up to function via a friction clutch 306, said centrifugal brake 305 is set up to be disconnected from the locking mechanism when the hook has arrived at a given angle from below.

37. Device according to one of the preceding claims 24-36, characterised in that the centrifugal brake is set up to be disconnected from the locking mechanism in that the position indicator 510 of the pre-tension unit (500) will lift the centrifugal brake 305 upwards so that the friction clutch 306 no longer engages and the generator shaft 303 can rotate freely without any influence from the centrifugal brake 305.

38. Device according to one of the preceding claims 24-37, characterised in that the integrated locking lip (604) is blocked from opening the hook entrance (109) in that its mounting to the hook is prevented to be pivoted with the help of a locking device in the form of a disc set up to slide along and close up to the arch-formed underside edge (129) of the housing part, whereby the bolt cannot be turned and the entrance 109 is mechanically locked in a closed position, but when the hook 108 is pivoted towards an open position it will be possible to push in the locking lip (604).

39. Device according to one of the preceding claims 24-38, characterised in that a mechanisms to control the locking lip from being locked out in a blocking position to be driven in as the entrance to the hook is opened between the two positions when the hook (108) is pivoted past a given angle in relation to the hook housing 104 from its lower position, and also that the lip 604 remains standing in an inswinging position when the hook is in its upper position.

40. Device according to one of the preceding claims 24-39, characterised in that an integrated locking lip (604) is set up to block the hook entrance (109) when the hook is rotated from its upper to its lower position.