Patent Application
20110133020
The present invention relates to delivery devices used for facilitating regular winding of a cable onto a cable drum. The invention relates more particularly to delivery devices capable of handling cables of different type and diameter or else of cables whose diameter varies greatly over their length.
The invention relates in particular, but not exclusively, to the winding of linear submarine acoustic antennas also known as “streamers”.
Stowing cable elements or streamers in a regular manner on a spiral consisting of contiguous turns requires the cable or streamer to be positioned in line with the turn to be wound. In other words, this operation requires that the cable be always positioned with the respect to the cable drum such that winding it produces contiguous turns. The term “streamer” is understood here to mean an element having a large diameter compared with a cable and which is bent by means of mechanical articulating elements and not continuously as in the case of a cable.
This positioning, as is known, is generally performed using a delivery device provided with a guide nut which makes it possible for the section of cable present at the cable drum to be oriented perpendicular to the axis of the cable drum, this being a necessary condition if the cable is to be wound up appropriately, in particular without one turn overlapping another.
The delivery system is, to this end, a system that can move translationally along an axis parallel to the rotational axis of the cable drum. The lateral movement follows the pitch of the turn to be wound and the guide nut prevents the cable opposite the turn to be wound from moving laterally and vertically. Consequently, the winding of the cable onto the cable drum is accompanied by a rotational movement of the cable drum and by a lateral reciprocating movement of the delivery system along this axis parallel to the axis of the cable drum. Matching the dimensions of the guide nut to the diameter of the cable or streamer to be wound makes it possible to precisely position the latter, this positioning ensuring winding uniformity.
While the techniques of winding a cable or similar object onto a cable drum are generally controlled, there nevertheless remain two particular points where improvements in relation to the prior art can be made.
A first point consists in satisfactorily controlling the winding of cables having very different diameters using a single delivery system. This first point also concerns, by extension, controlling the winding of cables having a non-constant diameter over their length and controlling the winding of objects of the streamer type. In the case of winding successive cable or streamers portions, these portions having different diameters and a random order, and the guide nut cannot be produced simply, without risking not being able to guide the cable properly during delivery.
A second point consists in taking satisfactory account of the orientation of the axis of the cable at the inlet to the delivery system with respect to the axis of the cable drum or more generally with respect to the position of the winch, the orientation of the cable upstream of the delivery system depending on the direction of the traction force exerted on the cable. In current systems, it is necessary to add, to the actual delivery means, means which act as a fairlead (trough) and which are thus intended to modify the orientation of the cable before it is taken into account by the actual delivery system. The installation of such means often takes up a lot of space because of the limitation on the fleet angles (bending angles) which a cable or streamer can support.
In order that cable of different diameters can be guided, there exist, in order to replace the simple guide nuts, various known means, such as:
However, besides the fact that these known means cannot easily be adapted for the case of a cable of variable cross section, they do not offer a solution for controlling the orientation of the cable at the inlet of the delivery system, such that the fairlead function is in all cases provided by means that are separate from the delivery means. This functional and structural distinction causes the existence of a relatively larger space between the fairlead intended to modify the orientation of the cable and the delivery, the space depending on the minimum curvature which can be imposed on the cable. This imposed arrangement thus generally leads to an increase in the space required.
It is an object of the invention to provide a response to the problems relating to the two points discussed hereinabove, namely:
To this end, one subject of the invention is a guiding device for multi-diameter cables, making it possible to guide a cable the diameter of which is between a value dmin and a value dmax. The device has a lower wall and two side walls defining a cable-guiding channel, a cable inlet area and an outlet area. The side walls each have a circular part, of radius of curvature R, the convexity of which is directed towards the channel. These circular parts are arranged along the respective side walls such that there are two parallel straight lines T1 and T′1 respectively at a tangent to one and the other of these circular parts and spaced apart by a distance d1 greater than or equal to dmax, and also two parallel straight lines T2 and T′2 respectively at a tangent to one and the other of the circular parts and spaced apart by a distance d2 less than or equal to dmin.
According to the invention, the radius R is defined as a function of the minimum radius of curvature that the cable assembly to be guided can support without being damaged.
According to the invention, the side walls are designed and arranged with respect to one another so as to define a channel at the flared ends. The cable inlet and outlet openings are defined so as to take into account a given maximum value for the angle made between the direction in which a cable enters the device and the direction in which it emerges from the device, and to ensure a minimum radius of curvature that the cable assembly to be guided can support without being damaged.
According to one embodiment of the invention, the lower wall which forms the base of the guiding channel has a curved profile in vertical cross section, the convexity being directed towards the inside of the channel, the curvature of the profile being determined as a function of the minimum radius of curvature that the cable assembly to be guided can support without being damaged.
According to one particular embodiment, the device according to the invention also comprises means for fixing it to a delivery system.
Another subject of the invention is a multi-diameter cable delivery system for winding a cable having a diameter between a value dmin and a value dmax onto a cable drum, which system includes a device according to the invention, the device being mounted on the delivery head so as to move laterally along an axis parallel to the rotational axis of the cable drum.
Due to its particular form, the device according to the invention has, compared with the known prior art, the advantage of having no moving parts such that automatic adaptation to the diameter of the cable takes place and no adjustment is required. The device according to the invention thus makes it possible for cables or streamers having a diameter which varies along their length to be guided automatically with constant precision.
Moreover, also due to its form, the device according to the invention can advantageously fulfil the fairlead function at the same time as the cable guide function. As a result, its use substantially reduces the size of the delivery system to be used for stowing a succession of cables or streamers of different diameters on a cable drum. In this way, the winch can advantageously be placed on the rear freeboard of the transport boat, for example.
The features and advantages of the invention will be better understood by virtue of the following description, which explains the invention by way of a particular embodiment taken as a non-limiting example and which is supported by the attached figures, in which:
Consideration is first given to
As has been described hereinabove, the cable guiding device according to the invention has a lower wall (not shown in the figure) and two approximately vertical side walls 11 and 12 delimiting a guiding channel 19. The two walls 11 and 12 indicated by two dotted lines each have a circular segment, in each case depicted by a circular arc 13 or 14 in the figure, extended on each side by a segment of any form, depicted in each case by one of the dotted lines 15 and 16 or 17 and 18. Each of the side walls thus consists of a circular segment, extended on each side by segments of any form, for example planar segments. According to the invention, the circular wall segments 13 and 14 have radii of curvature R of the same length. Their convexity is directed towards the inside of the guiding channel 17.
According to the invention, the walls 11 and 12 are arranged in a particular manner with respect to one another. In this case, the arrangement is intended to ensure that, for a cable with a diameter which is between a diameter dmin (i.e. greater than or equal to dmin) and a diameter dmax (i.e. less than or equal to dmax), whatever the orientation of the axis of the cable with respect to the device when it penetrates into the latter and taking account of the traction exerted on the cable, the cable is always in contact with at least one of the side walls as it passes through the device. Consequently, the walls 11 and 12 are arranged so as simultaneously to fulfil the following two conditions:
In this way, a guiding channel 19 is produced between the two walls 11 and 12, said guiding channel 19 having an area 111 in which it forms a dogleg. Advantageously, the form and dimensions of the dogleg thus obtained allow both a cable of diameter dmax following a curved path and, conversely, a cable of diameter dmin following an approximately rectilinear path to pass through it.
The wall segments 15 and 16 or 17 and 18 which respectively surround the circular segments 13 and 14 have a form and an orientation which make it possible to define openings 112 and 113 at the inlet and outlet of the device which each have a given form, orientation and dimensions. The form, orientation and dimensions of each opening are defined by the conditions of use of the device and also by the diameter of the cable and its possible orientation in relation to the device. In particular, the wall segments 16 and 18 on the one hand and 15 and 17 on the other must not be arranged in relation to one another such that they prevent the entry or exit of a cable of diameter dmax.
In other words, the cable inlet and outlet openings are defined so as to accept a given maximum value for the angle made between the direction in which a cable enters the device and the direction in which it emerges from the device, and to ensure a minimum radius of curvature which is suitable for the cable assembly to be guided, any one of the cables which the device is designed to guide being able to support this minimum radius of curvature without being damaged.
Designed in this way, the device according to the invention may advantageously, as has been described hereinabove, act as a fairlead in addition to its main role as a cable guide.
The radius of curvature R of the circular wall segments 13 and 14 is defined depending on the application in question, notably as a function of the values of dmin and dmax, and also as a function of the stiffness of the cables that the device is designed to guide. The practical result of this stiffness, for each of the cables to be guided, is the minimum value of the radius of curvature that can be applied to the cable in question without permanently damaging or deforming the latter. The radius of curvature R thus depends on the minimum radius of curvature that the cable assembly to be guided can support, any one of the cables which the device is designed to guide, and notably the stiffest cable, being able to support this minimum radius of curvature without being damaged.
In the rest of the description, the operating principle of the device according to the invention is described by way of a particular embodiment consisting of a cable guide intended to be integrated in the delivery system of a winch used to release a cable or streamer into the sea and to return this cable or streamer and stow it.
Consideration is now given to
From a practical point of view, the main function of the lower wall 21 of the device according to the invention is to hold the cable 22 to be guided between the side walls 11 and 12. To this end, it may assume various profiles. The device according to the invention may thus have a simply planar lower wall or else, as in the example of
As described above, the side wall segments which surround each of the circular segments, the segments 15 and 16 in the case of the circular segment 13 and the segments 17 and 18 in the case of the circular segment 14, are configured and arranged so as to define inlet and outlet openings complying with the requirements of the application in question.
Thus, as far as the example chosen is concerned, the side wall 11 has a circular segment 13 located close to the outlet opening 113 surrounded by an approximately rectilinear wall segment 16 terminating in a curved end 31 and defining the inlet opening 112, and by a short wall segment 15 which is rectilinear or slightly curved and defines with the circular segment 13 the outlet opening 113.
Similarly, the other side wall 12 has a circular segment 14 located close to the inlet opening 112, surrounded by an approximately rectilinear wall segment 17 defining the outlet opening 113, and by a short wall segment 18 which is rectilinear or slightly curved and defines with the circular segment 14 the inlet opening 112.
The wall segments are furthermore arranged with respect to one another in such a way as to satisfy the abovementioned conditions and to produce a dogleg in the guiding channel 19, the role of said dogleg being to ensure that the guided cable is permanently in contact with one or the other of the walls 11 or 12. In this way, whatever the orientation of the axis of the cable 22 at the inlet of the device, this orientation being illustrated by the arrows 31 to 33 in
Furthermore, where a device intended to be mounted on a system performing a more general function is concerned, for example a delivery system mounted on a winch, the device according to the invention is provided with appropriate means for it to be fixed on the system in question. These means may for example be attachment lugs 23 such as those shown in
Consideration is now given to
In this way, when the cable 45 penetrates into the guiding device 20 in a direction in between the direction 46 and the direction 47, it bears on the wall 11 in an area of variable size which becomes larger the closer the direction is to the direction 46. The profile of the wall 11 thus guides the cable as far as the outlet of the device, such that it follows a given fixed direction 49 which is approximately perpendicular to the cable drum of the winch onto which the cable must be wound, for example.
Similarly, when the cable 45 penetrates into the guiding device 20 in a direction in between the direction 48 and the direction 47, it bears on the wall 12 in an area of variable size which becomes larger the closer the direction is to the direction 48. At the same time, it bears on the opposite wall 11 at a point 412 such that at the outlet of the device it follows the fixed direction 49.
As the direction in which the cable penetrates into the guiding device 20 approaches the direction 47, the area where the cable bears on one of the walls becomes smaller and smaller until it is simply limited to two bearing points 411 or 412, one on each of the walls 11 and 12.
It should be noted at this point that, due to its diameter, the cable 55 is always simultaneously in contact with the walls 11 and 12 in the area 111 in the form of a dogleg in the guiding channel 19, in which area the spacing between the two walls equal to dmax is at a minimum.
It can thus easily be seen, considering
Consideration is now given to
According to a known principle, illustrated in
In comparison, as is illustrated in
The manner of using the device according to the invention described above makes it possible for the advantages provided by the invention, particularly in terms of ease of use, to be clearly understood. However, this use must not be considered to limit the subject matter of the invention or its scope. In particular, it does not exclude the possibility of adding additional, morphological or functional elements to the essential elements of the device that have been described hereinabove, which additional, morphological or functional elements make it possible to deal with particular configurations. Thus, for example, it is possible to add elements—bearings or the like—to the device, which make it easier for the cable to slide in the device according to the invention; these elements may, for example, be integrated into the lower wall and/or into the side walls. The advantage of adding such elements is particularly noteworthy when the cable to be guided is a particularly stiff cable (or streamer) which has a diameter close to dmax.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08 02593 | May 2008 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2009/055530 | 5/7/2009 | WO | 00 | 2/23/2011 |
