WO2012067521A1

WO2012067521A1 - Traction winch structure, an apparatus for a winch and use thereof

Info

Publication number: WO2012067521A1
Application number: PCT/NO2011/000325
Authority: WO
Inventors: Stig SVENØY; Jørn SALTHAMMER
Original assignee: Huse Engineering As
Priority date: 2010-11-19
Filing date: 2011-11-18
Publication date: 2012-05-24
Also published as: NO20101636A1

Abstract

There is provided a construction for a traction winch for serving a hoisting line, for implementing a heave compensation, comprising two mutually separated traction drums (32, 34) whose drum outer surfaces each comprise at least two mutually separated line tracks (41, 43; 45, 47) for arranging the line in a number of loops around the drums, and it is characterized in that a number of regulating sheaves (60, 62) are adapted to form extra loops of line between the traction drums (41 to 47) and the spooling up unit (10), in that the regulating sheaves (61, 62) are adapted for individual operation (70, 72), or to be freely coupled, for regulating the tension in the line between the traction drums (32, 34) and the spooling up unit (10). The invention concerns also an apparatus for a winch for serving a hoisting line, for implementing heave compensation, comprising in series: a traction winch, a tightening unit and a secondary winch for the line, wherein the tightening unit arrangement provides a buffer for holding the line between the traction winch and the secondary winch with substantially constant tension. There is also described a use thereof.

Description

TRACTION WINCH STRUCTURE, AN APPARATUS FOR A WINCH AND USE

THEREOF

The present invention concerns a new construction for a traction winch for operating a hoist line, for implementing heave compensation, comprising two mutually separated traction drums whose drum outer surfaces include at least two mutually separated line tracks for arranging the line in a number of loops around the drums, such as defined in the preamble to appended claim 1.

The invention also relates to an apparatus for a winch for operating a hoist line, for implementing heave compensation, such as defined in the preamble of appended claim 7.

Moreover, the present invention concerns a use of the aforesaid traction winch construction and apparatus.

The invention pertains to a technical field which concerns active heave compensation of hoist lines in connection with hoist equipment, especially for cranes, and especially for hoist lines/wires which maneuver a load, or cables such as signal- and electrical current cables which are maneuvered underwater by using winches. The invention is especially relevant to a traction winch construction in a system for operation of loads, where the vertical position of load is to be held most stable when a sea vessel is moving in waves. Another use concerns a situation wherein different equipment is to be lowered down into the sea in respect of precise positions, or when the vessel handles, install and set anchors onto the seabed. Furthermore, it is envisaged to provide a system which is capable of implementing so-called "direct in-line active heave compensation".

In the present text, the phrase "line" is used as a collective term for wires, ropes, cables, and so forth.

A system equipped with active heave compensation AHC ("active heave compensation") is required to provide a compensation for vertical movement of the crane boom, such that the load can be held calmly in position when the vessel moves in response to sea movement.

Known technology

There are earlier known systems for avoiding an occurrence of movement, namely for spooling out and spooling in, of an entirety of a total mass of a heave line (wire/cable) which lies wound up on a storage drum (also known as a "secondary winch") when the vessel moves in response to sea movement, namely something which can be a question of several tens of tons of wire mass. Therefore the secondary winch may be at stand still for long periods. In respect of known technology, reference is made to Norwegian patent no. NO- 324416, US patent applications US 2010/0224844, US-2008/0105433, US patent US 5, 351 , 430, French patent FR-2843954, German patent no. DE-3327974, patent application WO2008/022125, WO-81/01402 together with Japanese patent no. JP110498. US patent application no. US2008/0105433 describes a winch equipped with a heave compensation comprising a friction winch, a cylindrical arrangement and a secondary winch. However, there is used a separate unit for heave compensation and the solution comprises in addition a "traction winch, an intermediate "tensioning sheave"; and a drum or a so-called "take-up winch". This is in contrast to the solution of the present invention, wherein one envisages to construct the system such that it is a traction winch" which functions as a heave compensator.

According to the Norwegian patent NO-324416 (Odim), a traction winch comprises a number of line guiding sheaves or drums which are positioned alongside one another, such that the line lies sequentially over a line track on an outer surface of the drum. The construction comprises groups of sheaves which are disposed sideways in respect to one another. Each sheave is equipped with a separate drive unit. One of the disadvantages with this solution is that it is very complex, heavy and voluminous, especially on account of each line sheave in the two sets is equipped with a separate drive system. Object of the invention

It is an object of the invention to provide a novel system for active heave compensation, together with a completely new constructiion of a traction winch. It is further an object of the invention to provide a solution wherein the traction winch is implemented with a separate system for finely adjusting holding forces on the traction winch's low tension side to the tightening unit, and wherein the secondary winch's holding force can lie approximately in a range of 10% to 30% of the total line/rope from the load, or the secondary winch's brakes are fully engaged.

In respect of the present invention, account is taken to provide a winch system for heave compensation comprising three parts: a traction winch, a tightening unit and a secondary winch for the line. In such a system, it is the traction winch and the back tension unit which are adapted to undertake all necessary spooling-in and spooling- out of the line when the ship moves in response to sea motion. Concurrently, the total length of a buffer line which the tightening unit (in English denoted as "back tension") is able to handle, which determines to what extent the secondary winch must be activated for spooling-in or spooling-out line.

It is also an object to provide a solution, wherein the secondary winch in addition to performing a storage function for the main wire/line, implements itself a tightening function in a form of spooling-in and spooling-out the line in synchronism with the main winch's (traction winch's) movement.

The present invention

The construction pursuant the invention is distinguished in that a number of line regulating sheaves are adapted to form extra line loops between the traction drums and a spooling-up unit, in that the regulating sheaves are adapted for individual operation, or to be freely coupled, for regulating the section of the line between the traction drums and the spooling-up unit.

According to an advantageous emodiment of the invention, the regulating sheaves are individually adapted to be freely rotatable on the same axles as the traction drums, or on axles which are disposed sideways in relation the traction drums.

According to yet another advantageous embodiment it comprises two regulating sheaves.

According to yet another advantageous embodiment, each traction drum is adapted for individual operation, or to be freely coupled for rotating freely.

According to yet another advantageous embodiment, the spooling-up unit is a secondary winch for line storage, such that it can be driven by a motor for spooling-in and spooling-out the line on the secondary winch. According to another advantageous embodiment, the line between the secondary winch and the traction winch is adapted to be supplied through a tightening unit in the form of a back tension unit.

The apparatus for a winch for operating a hoisting line, for implementing heave compensation, comprises in sequence: a traction winch, a tightening unit and a secondary winch for the line, wherein the tightening unit provides a buffer for holding the line between the traction winch and the secondary winch with substantially constant tightening, wherein:

1) the hoisting line (40) is adapted to start with the secondary winch (10) which stores unused portions of the hoisting line (40) on a drum (12), and

2) the line (40) is arranged in loops around the sheaves (22, 24) in the tightening unit, in that an applied force from the cylinder (26) ensures a tight line (40) between the secondary winch (10) and the traction winch (30), in that the cylinder's (26) force can be varied for undertaking a task of holding a tight hoisting line (40) under different conditions, for example as arises when the weight of the load varies, characterized in that:

3) the line thereafter runs via profiled loops around a number of regulating sheaves (60, 62) for thereafter entering the two traction-drums (32, 34), wherein the winch (30) is used for pulling in and releasing out the hoisting line (40), for thereby providing a heave compensation.

The apparatus traction winch is moreover formed with the constructive features as defined previously (patent claims 1 to 6).

According to the present invention, there is used a traction winch construction and the apparatus in association with a winch for a hoisting facility, for example a crane boom, as well as for subsea-installations or anchoring, by employing an active function for compensating vertical movement of the ship when it moves in waves, such that the load is held in substantially a same vertical orientation.

According an alternative the traction winch construction and the apparatus is used in connection with a winch for a hoisting facility, where a load hangs at the end of a hoisting line from the hoist facility, for example a crane boom, such as for subsea installations, maneuvering anchors or for lifting of a load of another ship, by utilizing an active function for compensating for vertical movement of the ship where the crane is mounted, or wherein the load is disposed, such that the tension of the hoisting line is kept substantially constant (constant tension function). Detailed description of the invention

The invention will be described in the following in more detail with reference to the diagrams, wherein:

Figure 1 is an illustration in perspective view of a winch arrangement pursuant to the present invention;

Figure 2 is an illustration in cross-sectional view of the winch arrangement of Figure

1 pursuant to the present invention;

Figure 3 is an illustration in perspective view of the new construction of a traction winch pursuant to the invention; Figure 4 is an illustration in perspective of the winch arrangement for an embodiment, wherein the secondary drum in addition is operable to function to store the hoisting line, also to implement a tightening function of the line forward to the traction winch, namely wherein necessary spooling-in and spooling-out of the line in coordination with the movement of the line through the traction winch, is undertaken.

By way of introduction, reference is made to Figures 1 and 2.

The winch system, including the inventive traction winch, comprises three parts:

1) a secondary winch 10,

2) a tightening unit (English: back tension unit) 20; and

3) the traction winch 30 itself, and which functions in principle such that described in the foregoing. A hoisting line 40 from which a load 100 is hung is shown, and which is operated from the traction winch 30, and which is routed through the tightening unit which takes up (buffers) uptake and release of the line 40 under heave compensation, and is wrapped

(spooled in) onto the storage- or secondary winch 10.

1) The secondary winch 10 stores the line 40 on the winch drum 12, and during the heave compensation this winch stands at rest, with wrapped up line. In Figures 1 and 2, the drive motor is denoted by 11. This winch is adapted to store that portion of the line which does not need to be in use during the hoisting operation, in that it only spools in or out the line when the load 100 directly is to be hoisted or lowered, or possibly when the heave compensation's amplitude renders it necessary to employ a longer buffer line length in the tightening unit. 2) The line 40 from the secondary winch is directed into the passive hydraulic tightening unit formed from two or more separate guiding sheaves 22, 24 which are freely rotating and without motor drive. The line is laid in a double or four doubled loops about the guiding sheaves 22, 24. A passively operating piston cylinder unit 26 (or, as a secondary alternative, a mechanical spring) is suspended between the seats of the sheaves and forms a tightening arrangement so that the line 40 is maintained tightened in constant tension between the secondary winch 10 and the traction winch 30.

This tightening unit 20 includes an accumulator which stores energy when it is clamped together, and holds the line loops in tension, and which has similarities to a shock absorber. The force of the cylinder (or spring force) 26 can vary, for holding the line 40 tight with constant tension under different conditions, such as for coping with loads of different weight. The gas pressure of the accumulator 26 can be adjusted for coping with varying tow/line tension. In the alternative of a mechanical spring system, one does not normally have this possibility for changing the tightening unit's equivalent spring force.

The inventive traction winch 30, with its inventive line-guiding drum- or sheave- construction which provides the compensation, is shown in detail in Figure 3.

This traction winch unit 30 is implemented by way of first and second driven traction drums 32, 34, each comprising at least two recessed line guiding tracks, and is arranged in a framework. The traction drums 32, 34 have to a large extent substantially mutually parallel axes of rotation/axles 40, 42, and are each driven by an associated drive motor 50, 52. The traction winch can be mounted onto a foundation via support legs 140. At each drum's outer surface, there is namely formed mutually separated two or more recessed line tracks and where the line is laid in loops between the drums. Each drum can alternatively be constructed from at least two line guiding sheaves 41 , 43, respectfully 45, 47, and which are respectively stiffly attached mutually parallel in respect to one another. The at least two sheaves 45, 47 are, for example, treaded onto the axle 39. Each sheave comprises a recessed track around its periphery for guiding the line in a corresponding manner as for a drum. The line tracks are adapted in diameter to the type of line 40 which is employed in the actual winch.

In addition the traction winch includes at least one line sheave, namely in this case the line sheaves 60, 62, herewith referred to as regulating sheaves, which are adapted to define their own line loops around the two traction drums 32, 34 and the tightening unit 20. The regulating sheaves 60, 62 are driven by respective individual drive motors 70 respectively 72, and can therefore be controlled independently of one another and independently of the axles 39, 42. With controlled operation of the two drive motors 70, 72, the traction winch's holding force can be finely adjusted. The regulating sheaves 60, 62 can be located in the same frame as the traction drums/sheaves 41 , 43; 45, 47, such that they rotate on a same axle 39, 42, However, the regulating sheaves 60, 62 are driven/rotate independently from the sheaves/drums 41 , 43; 45, 47. The regulating sheaves 60, 62 can also be freely coupled (from the motor drive 70 respectively 72 ) to rotate freely, namely to be capable of rotating with the line's movement through the sheave tracks.

According to the embodiment illustrated in Figure 3, the regulating sheaves 60, 62 are positioned disposed sideways in the frame in relation to the axles 39, 42. This is an optional disposition, but can be more space saving in comparison to them being placed on the same axles as the traction drums 41 , 43; 45, 47. In Figure 3, there is shown the loops into which the line can be arranged during use of the present inventive new traction winch construction including the regulating sheaves pursuant to the invention.

In the Figure, the line 40 is illustrated as being guided up and over from a guide pulley in a virtual crane boom and forward in over the innermost sheave 45 in the first winch 32 wherein it turns 180° and is guided back over the sheave 41 of the other second winch 34, and thereafter back over the sheave 47 in the first winch. In this manner, the line forms a semicircular loops about the sheaves 45, 41 , 47, 43 before the line is guided in over the first regulating sheave 60, in order thereby to form a loop back over the second regulating sheave 62 before the line 40 is guided further in over the tightening unit.

This means that the line 40 turns 180° six times (also referred to as wraps) and forms in total three loops.

The number of active wraps can be chosen, such that there can be achieved an appropriate back support, amongst others depending on the actual frictional coefficient between the line and sheave tracks, the weight of the load and desired power utilization (and speed) in the traction winch. In other words, one or both of the sheaves 60, 62 can be freely coupled via a clutch or be controlled to follow passively movement of the line 40 without contributing to the total holding force of the winch. In the traction winch shown in Figure 3, the sheave 45 takes up the highest tensional force from the load.

The traction winch 30 is used to release out and pull in the line 40 and implement thereby the heave compensation function. This is the background for using the tightening unit between the traction winch and the secondary winch.

During normal hoisting and lowering of the load, and during heave compensation, the traction winch is operable to develop the main lifting force, wherein a remainder of the lifting force is provided by the secondary winch 10. Thus the line 40 comes in over the boom pulley 49, runs through the three loops, before it is guided into the tightening unit with the sheaves 22, 24 and forms single- or double loops. The tightening unit is a piston cylinder unit (alternatively a tensioning spring construction) for ensuring correct tightening of the line between the traction winch and the secondary winch.

An alternative solution provided by the invention is illustrated in appended Figure 4. In this solution, it is possible to omit the tightening unit (back-tension unit) 20 in Figures 1 to 3 from the arrangement. In many situations, the storage winch is expected to be able to respond fast enough and spool-out and spool-in the line/wire in response to movements of the main winch without a need for a separate tightening unit. In principal, the tightening unit is however an important part of the total and overall arrangement. The line 40 is therefore conveyed directly from the traction winch and into the drum 11 of the secondary winch 10.

Advantages provided by the system pursuant to the invention: it is feasible to achieve a rapid and accurate functioning heave compensation. when the heave compensation is performed by a winch (especially electrically driven), there is achieved a soft and precise control of movement of the system. This results in turn in less wear in all components of the crane, included on the hoisting line, and lower maximum dynamic line tension, and a more steady operation. during normal operation, the winch can be driven with considerable high speed, for example when it is used to handle loads at great ocean depths, on account of the AHC-operating mode being controlling and given by design for the drive system. on account of there being low moment of inertia both for the traction winch drums and the drive motors means that it is only necessary, with a moderate additional torque from the motors during AHC-operation, beyond the static force which is required for holding the load hanging in the line. the heave compensation, constant tension and any desired functionality can be easily implemented via the system's software, and can be modified at any point in time. Such functionality does not require any changes in the hardware configuration.

Claims

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

1. A construction for a traction winch for operating a hoisting line, for implementing heave compensation, comprising two mutually separated traction drums (32, 34) whose drum outer surfaces each comprise at least two mutually separated line tracks (41 , 43; 45, 47) for arranging the line in a number of loops around the drums, characterized in that a number of regulating sheaves (60, 62) is adapted to form extra line loops between the traction drums (41 to 47) and a spooling-up unit (10), in that the regulating sheaves (60, 62) are adapted for individual control (70, 72), or be released, for regulating the section of line between the traction drums (32, 34) and the spooling-up unit (10).

2. The construction as claimed in claim 1 , characterized in that the regulating sheaves (60, 62) are arranged to be individually freely rotatable on same axles as the traction drums (41 to 47), or on axles which are disposed sideways in relation to the traction drums (41 to 47).

3. The construction as claimed in any one of the claims 1 to 2, characterized in that the construction comprises two regulating sheaves (60, 62).

4. The construction as claimed in any one of claims 1 to 3, characterized in that each traction drum (32, 34) is adapted for individual operation, or to be freely coupled for rotating freely.

5. The construction as claimed in any one of the preceding claims, characterized in that the spooling-up unit is a secondary winch (10) for storing the line (40).

6. The construction as claimed in any one of the preceding claims, characterized in that intermediate secondary winch (20) and the traction winch is arranged a line tightening unit (20) in the form of a back tension unit.

7. Apparatus for a winch for operating a hoisting line, for implementing heave compensation, comprising in series: a traction winch, a tightening unit and a secondary winch for the line, wherein the tightening unit provides a buffer for holding the line between the traction winch and the secondary winch with substantially constant tension, wherein

1) the hoisting line (40) is arranged to start at the secondary winch (10) which stores unused portions of the hoisting line (40) onto the drum (12); and 2) the line (40) is arranged in loops around the sheaves (22,24) of the tightening unit, in that the applied force from a cylinder (26) ensures a tight line (40) between the secondary winch (10) and the traction winch (30), in that the force from the cylinder (26) can be varied for undertaking a task of maintaining a tight hoisting line (40) under different conditions, such that when a weight of a load (100) varies, characterized in that

3) the line thereafter is guided into profiled loops around a number of regulating sheaves (60, 62) for thereafter entering the two traction drums (32, 34), wherein the winch (30) is employed to pull in and release out the hoisting line (40), for thereby providing a heave compensation.

8. An apparatus as claimed in claim 7, characterized in that the traction winch is implemented with the construction features as defined in the preceding claims 1 to 6.

9. Use of a traction winch construction and apparatus as claimed in any one of the preceding claims, for implementing an active heave compensation for a ship's winch which is serving a load (100) via a hoisting line, for implementing subsea installations, maneuvering anchors or hoisting loads (100) on another ship, such that the load (100) is held in substantially a same vertical orientation and/or that the tension in the hoisting line is held substantially constant.