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EP 0 614 432 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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24.04.1996 Bulletin 1996/17 |
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Date of filing: 26.11.1992 |
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International application number: |
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PCT/NO9200/187 |
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International publication number: |
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WO 9311/036 (10.06.1993 Gazette 1993/14) |
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A DEVICE FOR TRANSFER OF PERSONNEL OR CARGO BETWEEN A FIXED OR FLOATING INSTALLATION
AND A BOAT IN A HIGH SEA
VORRICHTUNG ZUM ÜBERSETZEN VON PERSONAL ODER FRACHT ZWISCHEN EINERFESTEN ODER SCHWIMMENDEN
PLATTFORM UND EIN BOOT BEI SCHLECHTEM WETTER
DISPOSITIF SERVANT A TRANSFERER DES MEMBRES D'EQUIPAGE OU DES CARGAISONS ENTRE UNE
PLATEFORME FLOTTANTE OU FIXE ET UN BATEAU EN HAUTE MER
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Designated Contracting States: |
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FR GB IT NL |
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Priority: |
26.11.1991 NO 914628
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Date of publication of application: |
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14.09.1994 Bulletin 1994/37 |
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Proprietor: SELANTIC INDUSTRIER A/S |
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N-5363 Agotnes (NO) |
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Inventors: |
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- REE, Sigurd
N-6740 Selje (NO)
- LIEN, Eldar
N-6766 Kjölsdalen (NO)
- AARDAL, Käre
N-6740 Selje (NO)
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Representative: Boff, James Charles et al |
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c/o Phillips & Leigh
7 Staple Inn
Holborn London WC1V 7QF London WC1V 7QF (GB) |
(56) |
References cited: :
FI-B- 72 103 US-A- 2 876 919 US-A- 4 310 277
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US-A- 2 874 855 US-A- 3 591 022 US-A- 4 395 178
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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[0001] The invention concerns a device for transfer of personnel or cargo between a fixed
or floating installation and a boat in a high sea.
[0002] The installation may, e.g., be an oil platform, a quay or a loading ramp on shore.
The boat may be a rescue vessel, a cargo boat, a passenger ship, a fishing boat or
the like. In one embodiment, the primary application of the device can be as a means
of evacuation between the installation and the boat. In a second embodiment, the device
can principally be intended to function as a routine means of transport for personnel
or cargo, to and from an installation where wave motion or other factors often make
traditional connections by crane, gangway or the like difficult, time consuming or
hazardous.
[0003] One of the most important of the applications of the invention will be the transfer
of personnel and/or lighter goods between oil platforms and so-called standby vessels
or supply vessels. These vessels are very easy to manoeuvre and capable of coming
relatively close alongside the platform and maintaining relatively precisely the same
position for extended periods even in a high sea. However, even these vessels will
suffer motion amplitudes both horizontally and vertically which greatly complicate
cargo and personnel transfer between the vessels and the platforms. For heavier goods
this problem is generally solved by packing the goods securely in extremely solid
steel containers which can withstand heavy blows against the boat deck or against
other cargo. Nevertheless, there will naturally be limits to the how rough the sea
can be during which it is practically possible to perform such loading operations
with present day equipment. For transfer of cargo between two floating installations
or where loading operations have to be performed with a crane which itself is vulnerable
to wave motion, there exist so-called active or passive heave compensation systems.
These help to limit the cargo's wave accelerations either by suspending the cargo
by a spring system, e.g. pneumatically, or by registering the cargo's acceleration
or position by a sensor and processing it in a computer which transmits output control
signals to the crane in order to compensate for the inadvertent movements caused by
the waves. These systems can stabilise the cargo's movements during the cargo transfer,
but they still do not remove the horizontal and vertical shock loadings which can
occur when the cargo is lowered on to a boat deck which itself is in motion. The usual
means of transport for a small number of people or light-weight goods between boat
and platform is a so-called "basket" - a light and softly padded basket which is suspended
in a crane. Since the basket is soft and light there is little risk of damage to the
basket itself Moreover, it is possible for crew members on deck to take hold of the
basket without any great risk while it is still hanging freely in the crane hook,
and to help to control it in order to ensure a soft landing on the required spot on
deck. Nevertheless, the basket too is dangerous and difficult to use when there is
heavy wave motion, and moreover the basket will have a very limited capacity.
[0004] US-A-2874855 discloses a transfer apparatus between an offshore structure and a ship,
the apparatus comprising a boom and provided with means for tensioning a guide line
to keep it tensioned during movement of the ship.
[0005] A particularly complicated but also important problem is to evacuate people safely
from a platform to a standby vessel or other seaworthy rescue vessel in an emergency
situation. At present this usually has to be done indirectly by first taking the evacuating
personnel down into lifeboats or rafts in the water, or they jump directly into the
water in special survival suits, are picked up by so-called "mob-boats" or other vessels
and are finally transferred to a safer, preferably specially-equipped rescue vessel.
In most such evacuation systems the risk is very great, especially in a high sea.
Various attempts have therefore been made to find systems which can safely take evacuating
personnel directly from the platform to the rescue vessel, so-called "dry evacuation
systems". However, the problems with the relative wave movements have been so great
that to date there has been no breakthrough for any such systems on the market.
[0006] The object of the invention is to solve both this evacuation problem as well as other
more everyday problems when transferring small and vulnerable cargoes between platform
and boat. The system, however, can also successfully be used between two boats, or
from shore to boat where quay or jetty conditions are difficult.
[0007] The invention is as set out in the claims. In brief summary, a boom equipped with
a longitudinal transport passage is pivoted around a horizontal axis on the installation.
One outer end of the boom projects from the platform to a position over the boat deck
from where the cargo or person has to be lifted or lowered on to. Between the outer
end of the boom and the boat deck a guide wire is stretched. The boom is upwardly
suspended so that it follows the movements of the vessel's deck controlled by the
guide wire, which maintains a constant distance to the boat deck. In this way a cargo
can be controlled horizontally by slidable securing rings through which the guide
wire runs, while the vertical movement can be synchronized with the movements of the
boom and the deck. In this manner the cargo can be gently lowered on to the boat deck
irrespective of the deck's heaving motion in the waves. The heaving motion will be
absorbed gently and gradually by the cargo as the latter is pushed out on the boom,
and will correspondingly be gradually dampened when the cargo is pushed from the outer
end of the boom inward towards the boom's horizontal turning axis. At no time are
the cargo or the person to be transferred exposed to any jarring impacts.
[0008] Preferred embodiments of the invention will now be described with reference to enclosed
drawings, wherein
- Fig. 1
- illustrates an oil platform equipped with three devices according to the invention
(with booms 2), and where vessels 9 are connected to two of the devices, thus illustrating
the system in an operative condition.
- Fig.2a-c
- illustrate embodiments of a boom 2 as usable in the invention, where fig. 2a depicts
an open framework construction with an inserted longitudinal gangway or a conveyer
belt, while figs. 2b and c illustrate a longitudinal view and a cross section respectively
of a partially open framework boom 2 with a partially externally located closed gangway.
- Fig. 3a-b
- illustrates suspension of the boom 2 in substantially different positions, where 3a
illustrates an upwardly directed rest position where the boom's specific weight is
balanced against an upwardly directed spring force, while 3b illustrates upper and
lower outer positions for the boom's pendulum movement synchronously with the movements
of a connected boat deck in the waves. In both these positions in fig. 3b the boom
2 is held down by a tension in the guide wire 6 near the outer end of the boom.
- Fig. 4a-c
- show examples of suspension systems for the boom, where fig 4a illustrates a passive
hydropneumatic suspension 5 in which the characteristics can be adjusted manually
by gas valves and a hydraulic pump 10. Fig. 4b illustrates an active hydropneumatic
suspension system controlled by computer-processed signals from a tension sensor 13
on the guide wire 6. Fig. 4c illustrates a suspension system in the form of a heave
compensating constant tension winch 14.
- Fig. 5
- shows a connection between boat 9 and boom 2 being set up, in which the connecting
ropes are winched down on to the boat deck.
- Fig. 6
- shows the invention in use for transport of personnel down to the boat.
- Fig. 7
- shows an embodiment of the transport means between boom and boat deck whereby personnel
or cargo can be transferred via two evacuation stockings 15 and a lift.
- Fig. 8
- shows an embodiment which is primarily intended for two-way transfer of cargo.
[0009] In interpreting the following reference should be made to the last page of description
which includes a list of reference characters for guidance.
[0010] In the following embodiment, which is primarily intended for the evacuation of personnel
from oil platforms, the actual transport means is composed of a gangway on the boom
2, together with an arrangement with two evacuation chutes or socks 15 and a lift
between the end of the boom 2 and the boat deck.
[0011] The boat's (vessel 9's) movements in the waves are gradually transferred to the evacuating
personnel in that initially only one degree of freedom of the motion (the vertical
heave motion) is absorbed while the evacuee moves out towards the outer end of the
boom. Thereafter horizontal movements are also gradually transferred as the evacuee
slides down through the evacuation sock 15 or goes with the lift. Finally the rolling
and pitching motions are also absorbed when the evacuee lands on a soft padding (inflated
rubber dinghy) in the middle of the vessel's deck. In this manner the evacuee - or
for that matter also any goods in the lift - avoids all the violent and sudden jolts
which are otherwise liable to occur during the transfer of personnel or cargo during
rough sea conditions, if the conditions at all allow transfer with other technology
to take place.
[0012] In the embodiment there are proposed three parallel, linked "sock runs" 15, two of
which are equipped with slide boards ("Skyscape") in such a way that it is a simple
matter to climb over from one sock run to the other. The third sock run has no slide
board but instead a lift, which is primarily intended for wounded on a stretcher.
(Apart from the evacuation situation the lift can be used for ordinary transport of
goods between supply/standby vessel 9 and platform).
[0013] The advantage with several sock runs is greater capacity and reduced risk of a blockage
of, e.g., panicking people or people who are temporarily stuck in the sock due to
non-regulation clothing or the like. Safe evacuation of the injured has a double effect:
Firstly, evacuation of the injured in itself is naturally important. Secondly, if
one should be injured, the certainty that there is still hope of being rescued is
a factor which reduces the risk of the spread of panic. The latter applies particularly
in a queue situation or if someone requires to postpone his own evacuation on account
of essential work on the platform. From this point of view a lift also offers a better
chance of returning to the platform.
[0014] For the sake of clarity the embodiment will now be described by means of an evacuation
procedure with reference to the technical details which are vital for each step of
the procedure.
0. The boom is in a state of readiness in its upper position.
The boom has hydropneumatic suspension. It is normally in a state of full readiness
in an upper rest position. A manually controlled hydraulic pump is used for refilling
in the case of leakage, which will be immediately detected since the boom drops slightly.
(The pump can also be used for manual lifting and lowering of the boom, but this is
not a part of the standard procedure).
1. The vessel takes up a position under the boom.
The vessel will take up a position with its bow into the weather and reverse the afterdeck
in under the boom. From the bridge the captain will have a complete all-round view
of the afterdeck, the boom and the platform. The captain has the choice of using either
dynamic positioning (DP) or manual positioning.
2. Two rope ends are dropped on to the deck from the outer end of the boom.
The rope ends are light, strong rope, e.g. Kevlar, with padded sandbags shackled on
at the end. They can be released from the platform deck before anyone has gone out
on the boom. One of the rope ends has a tensile strength of at least 10 tons. The
other has a calibrated breaking strength of approximately 8 tons, and is intended
for use on random rescue vessels which do not have their own mooring winch. If the
rope ends do not land on the deck, they can be picked up with a boathook when the
vessel manoeuvres alongside.
3. The vessel threads the rope end around a pulley on the deck on to which the sock
is to be lowered, and winches the rope end down with a winch with a mooring function
of approximately 8 tons.
The rope end is attached to the lowest reinforcing ring in the sock, which is reinforced
for the purpose. When the rope end is pulled down, an approximately 500 kg heavy perforated
weight is pulled down simultaneously. See figs. 5 and 6.
The weight is suspended in two pulleys mounted a considerable distance above the weight's
centre of gravity. The weight is further controlled in that the rope end is threaded
through a long sleeve on the weight. On the pulleys runs a guide wire, one end of
which is fixed to the boom, and the other end reeled up on a winch with a 0.5 ton
slipping clutch mounted on the boom. The guide wires are threaded in the normal manner
through all the reinforcing rings on the sock.
When the rope end is stretched, the slipping clutch on the winch will keep the guide
wires taut while the sock unfolds in the normal manner during lowering. The lowest
cell in the sock is permanently attached to a special raft, which provides a nonimpact
reception area on deck, which can hold a few people, and which is capable of carrying
these people safely if the vessel is suddenly disconnected. The raft is floating freely
on the weight with runners for the guide wires.
The raft is automatically inflated when the rope end is stretched. At the same time
the guide wire winch is started. (Both parts have manual backup).
When the vessel has winched down the weight and the raft (which also acts as padding
for the weight) so far that the sock is completely extended, the boom will be pulled
behind it.
When the weight reaches the vessel's deck, the boom will swing around with the wave
motion in an approximately horizontal position (somewhat depending on ebb/flow). The
weight has sprung support legs with friction elements which prevent it from rotating
around the rope end when it has been pulled right down to the deck. Otherwise the
rope end is the only securing element between the sock and the vessel.
The length of the rope end is adapted so that it lets go of the winch if the vessel
has to leave, before the tensile strength in the winch attains too great a horizontal
component in relation to the dimensioning of the boom.
4. The crew on deck stretches a guide rope as "support rail" between the raft and
the hospital or other doors in the vessel's superstructure.
The guide ropes are attached to the raft at attachment points which withstand the
tension that is necessary for the purpose and no more.
5. Door from platform to footbridge on the boom is opened.
6. The evacuation can begin.
See fig. 6.
7. When all personnel have been evacuated, the guide ropes are first untied from the
raft. Thereafter the winch which holds the rope end is disconnected, and the vessel
leaves the platform.
This causes the boom to return to its upper position in a controlled manner, hydraulically
dampened. At the same time the winch will gently hoist the sock with the inflated
raft.
Evacuation of injured personnel:
[0015]
8. Injured personnel are strapped to a stretcher which is suspended in a "sock lift"
operated by an ordinary electrical winch with manual pulley and centrifugal brake
as backup.
The lift consists principally of a vertical steel frame slightly higher than the height
of a man, which is controlled between internal reinforcing rings slightly smaller
in diameter than external reinforcing rings to which they are welded. The tension
release wires carry the outer rings, while the internal rings act as fenders for the
lift.
Backup functions:
If there are found to be more personnel on the platform requiring evacuation after
the vessel has cast off:
[0016]
1. The same vessel, or another vessel, comes back and connects up to the platform
again. The dry evacuation continues in the same way as before.
2. If no new vessels are ready for dry evacuation:
- The boom is lowered to its lower position, so that the raft is floating on the water.
(This is done either by operating the manually controlled hydraulic pump, or -
in the case of a "dead platform" - by releasing gas from the gas cylinders. In the
former case it can be lifted again and connected to a new vessel later).
- Evacuation is carried out to the raft instead of to the boat deck. Extra rafts are
attached to the reception raft.
If the vessel has to move 10-20 metres further away with all haste:
[0017]
1. The captain orders full speed away from the platform.
2. The mooring winch releases rope end in a controlled manner and without losing the
connection.
3. The raft lifts a few metres off the deck if the boom reaches its lower end position.
The guide ropes between the superstructure and the raft are then pulled in a disciplined
manner into the attachment point on the raft.
4. The vessel can return at any time, winch the raft down on to the deck and continue
the evacuation without having to be connected again. In the meantime the evacuees
in the raft and sock sat waiting safely.
If the vessel has to move right away from the platform:
[0018]
1. The winch is disconnected, or the mooring function releases the entire rope end.
The lateral forces on the boom cannot be so very great since the tension in the rope
end will have a limited horizontal component irrespective of the direction in which
the vessel is travelling, due to the height up to the boom.
2. The boom can be lowered and evacuation to the rafts can be continued.
Use of the invention for ordinary transport of personnel and goods.
[0019] The lift which in the embodiment is primarily included for evacuation of the injured,
can of course be adapted for an application as a primary transport means for goods
or personnel, without this falling outside the scope of the invention. In this case
the previously described evacuation socks, for example, can be omitted entirely in
order to make room for a lift with correspondingly greater dimensions. The gangway
on the boom can then be replaced with or complemented by a conveyer belt. The need
for such transport means for routine use in the North Sea is obvious, when the present
day expensive helicopter transport costs are taken into consideration.
EXPLANATION TO THE DRAWINGS:
[0020]
FIG. 3A: REST/READINESS POSITION The boom is suspended on the gas springs. The top of the boom is far enough out to
enable the rope end in free fall to be picked up on the deck of the vessel. The boom
is not in the way of supply traffic. Moderate pressure in the gas springs.
Fig. 3B: OPERATIVE POSITION
1) A relatively acute angle of attack (w) gives great tensile forces, but little migration
(moderate force amplitude) between the upper and lower operative positions.
2) The cylinder abuts against end stop when the angle of the boom reaches -10 degrees.
This limits the horizontal component of tension in the stocking if the vessel leaves
without releasing the rope end.
COMMENTS TO FIG. 5:
[0021]
- Attachment point for guide rope ("Supoort rail") broken in case of excessive load
- Special raft which is supported by the weight and can only fall during lifting
- Pulley in the middle of the deck
IN THE DRAWINGS THE FOLLOWING REFERENCE NUMBERS ARE USED:
[0022]
- 1
- Hydropneumatic suspension
- 2
- Boom
- 3
- Arm
- 4
- Supporting wire
- 5
- Heave compensating cylinder
- 6
- Guide wire
- 7
- Gas tank
- 8
- Oil tank
- 9
- Vessel
- 10
- Manually controlled pump
- 11
- Computer controlled pump
- 12
- Computer module
- 13
- Tension sensor
- 14
- Heave-compensating winch
- 15
- Net
- 16
- Guide wire
- 17
- Pulleys
- 18
- Tension release wire
- 19
- Low coaming
- 20
- Inflated coaming
- 21
- Soft, sprung foot
- 22
- Rope end during winching
- 23
- Winch 8 tons
- 24
- Rope end
- 25
- Perforated weight
- 26
- Boom
- 27
- Attachment of one end of guide wire
- 28
- Guide wire to winch
- 29
- Roller for guide wire
- 30
- Net slide
- 31
- Strong termination for tension releasing suspended in a universal joint
- 32
- Guide wire
- 33
- Superstructure
- 34
- External reinforcement rings
- 35
- Internal reinforcement rings
- 36
- Guide wire winch
- 37
- Lift winch
1. A device for transfer of personnel or cargo between a fixed or floating installation
and a boat (9) in a high sea,
characterized in that a boom (2,26) equipped with a longitudinal transport passage
is pivoted around a horizontal axis on the installation, that one outer end of the
boom (2,26) projects over a position to which a boat deck can be manoeuvred, that
there is set up at least one approximately vertical rope or wire connection (6,16)
of approximately constant length between the deck and the outer end of the boom (2,26),
that the outer end of the boom (2,26) is upwardly suspended around the said horizontal
axis, thus keeping the rope or wire taut despite the movements of the boat in the
waves, and that the rope or wire connection (6,16) serve as a guide rope or guide
wire for a transport means in the form of a chutelike rescue sock (15), slide, lift,
stairway, gangway or the like between the outer end of the boom (2,26) and the boat
deck.
2. A device according to claim 1,
characterized in that the boom is upwardly suspended by means of a passive spring
device (1), that the boat is equipped with a winch (23), that a rope or wire connection
(6,16) is established by dropping the rope on to the boat deck from the outer end
of the boom (2,26), that the rope is connected to the said winch (23), and that the
winch (23) is dimensioned so as to pull the boom (2,26) closer to the boat deck by
overcoming the boom's upwardly directed spring force, and that the winch pulls the
boom so far down that the upwardly directed spring force preferably during the entire
course of the wave motion becomes greater than the weight of the cargo which has to
be suspended between the outer end of the boom (2,26) and the boat deck.
3. A device according to claim 2,
characterized in that the passive spring device (1) comprises a hydraulic cylinder
(5) connected to a hydropneumatic accumulator (5,7), and that the spring characteristic
can be adjusted by altering the amount of gas and/or liquid in the accumulator with
pump and/or valve devices (10,11) provided for this purpose.
4. A device according to claim 1,
characterized in that the outer end of the boom (2,26) is upwardly suspended by means
of the tensile force in a wire (4) stretched from a point out on the arm (3) of the
boom (2,26) and upwards directly or via a pulley to a slipping winch permanently connected
to the same installation as the boom's pivot axis.
5. A device according to claim 1,
characterized in that the boom (2,26) is upwardly suspended by means of an active
hydropneumatic spring system, whereby a tension sensor (13) in the rope connection
(6,16) to the boat deck provides continuous control signals via a computer (12) to
pumps and valves (10,11) in order to adjust the spring forces depending on the tension
in the said rope connection (6,16).
6. A device according to one or more of the preceding claims,
characterized in that a winch (23) on the boat deck which maintains the rope or wire
connection (6,16) with the end of the boom (2,26) has a slipping clutch which ensures
that a little more rope is paid out temporarily if the sluggishness in the boom's
or the cargo's movements causes tension in the rope which exceeds a calculated tolerance
limit.
7. A device according to claim 6,
characterized in that the winch (23) temporarily reels in more rope if the tension
in the rope due to sluggishness in the boom's or the cargo's movements falls below
a predetermined tolerance limit in particularly large individual waves.
8. A device according to one or more of the preceding claims,
characterized in that there are at least two independent rope connections (16,18)
between the boom and the boat deck, the first (18) of which rope connections is intended
to keep the boom (2,26) at as constant a height as possible over the boat deck, while
a second rope connection (16) is connected to a slipping winch which does not have
sufficient tensile force to overcome the boom's spring forces, but which supplies
sufficient tensile force to
keep the rope taut, thus enabling it to be suitable for use as a guide rope for the
transport means even though the distance between the end of the boom and the boat
deck should vary somewhat despite the first rope connection (18).
1. Vorrichtung für den Transport von Personen oder Fracht zwischen einer festen oder
schwimmenden Anlage und einen Boot (9) auf hoher See, dadurch gekennzeichnet, daß
ein mit einer länglichen Transportpassage ausgestatteter Ausleger (2, 26) um eine
horizontale Achse auf der Anlage gedreht wird, daß ein äußeres Ende des Auslegers
(2, 26) über eine Position vorsteht, zu der ein Bootsdeck manövriert werden kann,
daß wenigstens eine etwa senkrechte Tau- oder Drahtseilverbindung (6, 16) von etwa
konstanter Länge zwischen dem Deck und dem äußeren Ende des Auslegers (2, 26) eingerichtet
ist, daß das äußere Ende des Auslegers (2, 26) oben um die genannte horizontale Achse
aufgehängt ist, so daß das Tau oder Drahtseil trotz der Bewegungen des Bootes in den
Wellen gespannt gehalten wird, und daß die Tau- oder Drahtseilverbindung (6, 16) als
Führungstau oder Führungsdrahtseil für ein Transportmittel in der Form eines rutschenartigen
Rettungsschlauches (15), einer Rutsche, eines Lifts, einer Treppe, einer Gangway oder
dergleichen zwischen dem äußeren Ende des Auslegers (2, 26) und dem Bootsdeck dient.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der Ausleger oben mit Hilfe
einer passiven Federvorrichtung (1) aufgehängt ist, daß das Boot mit einer Winde (23)
ausgestattet ist, daß eine Tau- oder Drahtseilverbindung (6, 16) durch Fallenlassen
des Taus vom äußeren Ende des Auslegers (2, 26) auf das Bootsdeck hergestellt wird,
daß das Tau mit der genannten Winde (23) verbunden ist und daß die Winde (23) so dimensioniert
ist, daß sie den Ausleger (2, 26) durch Überwinden der aufwärtsgerichteten Federkraft
des Auslegers näher zum Bootsdeck hinziehen kann, und daß die Winde den Ausleger so
weit nach unten zieht, daß die aufwärts gerichtete Federkraft vorzugsweise während
des gesamten Verlaufs der Wellenbewegung größer wird als das Gewicht der Fracht, die
zwischen dem äußeren Ende des Auslegers (2, 26) und dem Bootsdeck abgestützt werden
muß.
3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die passive Federvorrichtung
(1) einen Hydraulikzylinder (5) umfaßt, der mit einem hydropneumatischen Akkumulator
(5, 7) verbunden ist, und daß die Federeigenschaft durch Ändern der Menge an Gas und/oder
Flüssigkeit in dem Akkumulator mit für diesen Zweck vorgesehenen Pumpen- und/oder
Ventilvorrichtungen (10, 11) verstellt werden kann.
4. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das äußere Ende des Auslegers
(2, 26) mit Hilfe der Zugkraft in einem Drahtseil (4) oben aufgehängt ist, der von
einem Punkt in der Nähe des äußeren Endes des Arms (3) des Auslegers (2, 26) nach
oben unmittelbar oder über eine Scheibe zu einer Rutschwinde gespannt ist, die permanent
mit derselben Anlage verbunden ist wie die Schwenkachse des Auslegers.
5. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der Ausleger (2, 26) oben
mit Hilfe eines aktiven hydropneumatischen Federsystems aufgehängt ist, so daß ein
Spannungssensor (13) in der Tauverbindung (6, 16) zu dem Bootsdeck über einen Computer
(12) kontinuierliche Steuersignale zu Pumpen und Ventilen (10, 11) sendet, um die
Federkräfte in Abhängigkeit von der Zugkraft in der genannten Tauverbindung (6, 16)
zu verstellen.
6. Vorrichtung nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet,
daß eine Winde (23) auf dem Bootsdeck, die die Tau- oder Drahtseilverbindung (6, 16)
mit dem Ende des Auslegers (2, 26) aufrechterhält, eine Rutschkupplung aufweist, die
gewährleistet, daß vorübergehend etwas mehr Tau abgewickelt wird, wenn die Schwergängigkeit
in den Bewegungen des Auslegers oder der Fracht eine Zugspannung in dem Tau verursacht,
die eine errechnete Toleranzgrenze übersteigt.
7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die Winde (23) vorübergehend
mehr Tau aufwickelt, wenn die Zugspannung in dem Tau aufgrund einer Schwergängigkeit
in den Bewegungen des Auslegers oder der Fracht bei besonders großen Einzelwellen
unter eine vorbestimmte Toleranzgrenze fällt.
8. Vorrichtung nach einem oder mehreren der vorhergehenden Ansprüche, dadurch gekennzeichnet,
daß wenigstens zwei unabhängige Tauverbindungen (16, 18) zwischen dem Ausleger und
dem Bootsdeck vorhanden sind, wobei die erste (18) dieser Tauverbindungen den Ansleger
(2, 26) auf einer möglichst konstanten Höhe über dem Bootsdeck halten soll, während
eine zweite Tauverbindung (16) mit einer Rutschwinde verbunden ist, die keine ausreichende
Zugkraft besitzt, um die Federkräfte des Auslegers zu überwinden, deren Zugkraft aber
ausreicht, um das Tau gespannt zu halten, so daß es für den Einsatz als Führungstau
für das Transportmittel geeignet ist, auch wenn der Abstand zwischen dem Ende des
Auslegers und dem Bootsdeck trotz der ersten Tauverbindung (18) etwas variieren sollte.
1. Dispositif pour transférer du personnel ou du fret entre une installation fixe ou
flottante et un bateau (9) en haute mer,
caractérisé en ce qu'une flèche (2, 26) équipée d'un passage de transport longitudinal
est montée à pivot autour d'un axe horizontal sur l'installation, en ce qu'une extrémité
extérieure de la flèche (2, 26) fait saillie au-dessus d'une position à laquelle un
pont de bateau peut être manoeuvré, en ce qu'au moins une connexion approximativement
verticale par cordage ou par câble (6, 16), de longueur approximativement constante,
est disposée entre le pont et l'extrémité extérieure de la flèche (2, 26), en ce que
l'extrémité extérieure de la flèche (2, 26) est suspendue vers le haut autour dudit
axe horizontal, conservant ainsi le cordage ou le câble tendu en dépit des mouvements
du bateau dans les vagues, et en ce que la connexion par cordage ou par câble (6,
16) sert de cordage de guidage ou de câble de guidage pour des moyens de transport
ayant la forme d'une chaussette de sauvetage par chute (15), d'une glissière, d'un
ascenseur, d'un escalier, d'un couloir ou analogue entre l'extrémité extérieure de
la flèche (2, 26) et le pont du bateau.
2. Dispositif selon la revendication 1,
caractérisé en ce que la flèche est suspendue vers le haut au moyen d'un dispositif
élastique passif (1), en ce que le bateau est équipé d'un treuil (23), en ce qu'une
connexion par cordage ou par câble (6, 16) est établie par descente du cordage sur
le pont du bateau à partir de l'extrémité extérieure de la flèche (2, 26), en ce que
le cordage est connecté audit treuil (23), et en ce que le treuil (23) est dimensionné
afin de rapprocher la flèche (2, 26) du pont du bateau par traction en surmontant
la force élastique dirigée vers le haut de la flèche, et en ce que le treuil tire
la flèche assez loin vers le bas pour que la force élastique dirigée vers le haut,
de préférence sur la totalité du mouvement de la vague, devienne plus grande que le
poids du fret qui doit être suspendu entre l'extrémité de la flèche (2, 26) et le
pont du bateau.
3. Dispositif selon la revendication 2,
caractérisé en ce que le dispositif élastique passif (1) comprend un vérin hydraulique
(5) connecté à un accumulateur hydropneumatique (5, 7), et en ce que les caractéristiques
élastiques peuvent être ajustées en modifiant la quantité de gaz et/ou de liquide
dans l'accumulateur à l'aide de dispositifs à pompes et/ou à vannes (10, 11) prévues
à cet effet.
4. Dispositif selon la revendication 1,
caractérisé en ce que l'extrémité extérieure de la flèche (2, 26) est suspendue vers
le haut au moyen de la force de traction d'un câble (4) s'étendant d'un point extérieur
sur le bras (3) de la flèche (2, 26) et vers le haut directement ou par intermédiaire
d'une poulie jusqu'à un treuil glissant connecté de façon permanente à la même installation
que l'axe de pivot de la flèche.
5. Dispositif selon la revendication 1,
caractérisé en ce de la flèche (2, 26) est suspendue vers le haut au moyen d'un système
élastique hydropneumatique actif dans lequel un détecteur de tension (13) dans la
connexion par cordage (6, 16) au pont du bateau fournit des signaux de commande continus
par l'intermédiaire d'un ordinateur (12) à des pompes et vannes (10, 11) afin d'ajuster
les forces élastiques en fonction de la tension dans ladite connexion (6, 16) par
cordage.
6. Dispositif selon l'une ou plusieurs des revendications précédentes,
caractérisé en ce qu'un treuil (23) disposé sur le pont du bateau, qui maintient la
connexion par cordage ou par câble (6, 16) avec l'extrémité de la flèche (2, 26),
comporte un embrayage glissant qui laisse filer temporairement un petit supplément
de cordage si les mouvements lents de la flèche ou du fret entraînent une tension
dans le cordage qui dépasse une limite de tolérance calculée.
7. Dispositif selon la revendication 6,
caractérisé en ce que le treuil (23) embobine temporairement davantage de cordage
si la tension dans le cordage due aux mouvements lents de la flèche ou du fret chute
en-dessous d'une limite de tolérance prédéterminée sur des vagues individuelles particulièrement
grandes.
8. Dispositif selon une ou plusieurs des revendications précédentes,
caractérisé en ce qu'il y a au moins deux connexions indépendantes par cordage (16,
18) entre la flèche et le pont du bateau, la première connexion par cordage étant
destinée à maintenir la flèche (2, 26) à une hauteur aussi constante que possible
au-dessus du pont du bateau, tandis que la deuxième connexion par cordage (16) est
connectée à un treuil glissant qui n'a pas suffisamment de force de tracton pour vaincre
les forces élastiques de la flèche mais qui fournit suffisamment de force de traction
pour maintenir le cordage tendu, étant ainsi adaptée à une utilisation en tant que
cordage de guidage pour les moyens de transport même si la distance entre l'extrémité
de la flèche et le pont du bateau devait varier quelque peu en dépit de la première
connexion par cordage (18).