Note: Descriptions are shown in the official language in which they were submitted.
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GUIDING DEVICE FOR MULTI-DIAMETER CABLES
The present invention relates to spooling gear devices used for
facilitating regular winding of a cable onto a reel, a cable drum. The
invention
relates more particularly to spooling gear 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 spooling
gear 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 spooling gear 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
3o reciprocating movement of the spooling gear 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.
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A first point consists in satisfactorily controlling the winding of cables
having very different diameters using a single spooling gear. 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, the
guide nut cannot be produced simply, without risking not being able to guide
the cable properly during the spooling.
A second point consists in taking satisfactory account of the
orientation of the axis of the cable at the inlet to the spooling gear 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 spooling
gear depending on the direction of the traction force exerted on the cable. In
current systems, it is necessary to add, to the actual spoolingmeans, 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 spooling
gearitself. 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:
- cable guides with moving parts catering for the different cable
diameters; the moving parts must be set manually or using remote-controlled
mechanical actuators so as to take into account the cross section of the
cable in question;
- cable guides with specific forms of the "pulley sheave" type which are
able to accept cables of different diameters but which, on the other hand, do
not very precisely guide the cable to be wound.
However, besides the fact that these known means cannot easily be
3o 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
spooling
gear, such that the fairlead function is in all cases provided by means that
are
separate from the spooling 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 spooling gear, the
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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:
- that of enabling precise spooling of cables or streamers of different
diameters, or else of cables or streamers having a variable diameter;
- that of positioning the axis of the cable or of the streamer such that at
the outlet from the spooling gear the axis of said cable or streamer is
perpendicular to the axis of the cable drum.
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 Ti 'respectively 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 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 with 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
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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 spooling gear device.
Another subject of the invention is a multi-diameter cable spooling
gear 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
1o the invention, the device being mounted on the spooling gearhead 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
spooling gear device 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:
- Figure 1 shows a schematic diagram illustrating the form features of
the device according to the invention;
- Figure 2 shows a schematic illustration, in profile view, of an
embodiment of the guiding device according to the invention;
- Figure 3 shows a schematic illustration, in a view from above, of the
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embodiment in Figure 2;
- Figures 4 and 5 show illustrations of the operating principle of the
device according to the invention;
- Figure 6 shows a schematic illustration of a spooling geardevice
5 having a conventional spooling head; and
- Figures 7 and 8 show schematic illustrations of a spooling gear
device having the device according to the invention.
Consideration is first given to Figure 1 which illustrates the essential
1o features of the device according to the invention by way of a simplified
schematic view from above.
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:
- there is a tangent T1 to one of the circular wall segments, 13 or 14,
such that the distance d1 of T1 from the straight line Ti 'parallel to T1 and
tangent to the other circular wall segment, respectively 14 or 13, is greater
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than or equal to the diameter dmax; and
- there is a tangent T2 to one of the circular wall segments, 13 or 14,
such that the distance d2 of T2 from the straight line T'2 parallel to T2 and
tangent to the other circular wall segment, respectively 14 or 13, is less
than
or equal to the diameter dmin.
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,
1o 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 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
3o 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
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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 all the cables 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
1o consisting of a cable guide intended to be integrated in the spooling gear
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 Figures 2 and 3 which schematically
show an embodiment of the device according to the invention adapted for the
production of a cable guide intended to be integrated into the spooling gear
of a winch.
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 Figure 2, a lower wall 21 the profile
of
which is curved longitudinally. The latter configuration advantageously makes
it possible, as illustrated in the figure, to take account of the fact that
the
cable 22 to be guided is not generally horizontal and level with the inlet
opening 19 of the device and that, as a result, its passage through the device
brings about a curvature of the cable 22 in the vertical plane, it being
possible
for the curved form of the lower surface of the device to limit this curvature
to
a value which does not damage the cable.
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
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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 Figure 3, and whatever the diameter of the guided cable,
the latter assumes at the outlet of the device a constant orientation depicted
by the arrow 34 in Figure 3.
Furthermore, where a device intended to be mounted on a system
performing a more general function is concerned, for example a spooling
gear device 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 Figures 2 and 3.
Consideration is now given to Figures 4 and 5 which illustrate the
operating principle of the device according to the invention. This principle
assumes that the guided cable is under tension, the direction of which
tension is depicted by the dotted arrows 41 to 44 in Figure 4 and by the
dotted arrows 51 to 54 in Figure 5. Depending on the application in question,
this tensioning may have various causes. In the case where the device
according to the invention is integrated into the spooling gear of a winch
intended to put into use a submarine cable (streamer), this case being taken
as an exemplary embodiment, the tension in the cable at the device results
from the traction of the winch which is exerted on the cable at the outlet of
the device and from the traction exerted thereon by its own weight at the
inlet
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of the device. The direction of the traction force exerted by the winch is
approximately perpendicular to the rotational axis of the cable drum, while
the direction of the traction force at the inlet is determined by the
orientation
of the axis of the cable with respect to the device.
Figure 4 illustrates the particular extreme case of guiding a cable 45
the diameter of which is equal to dmin, the smallest diameter that the device
can handle. As illustrated in the figure, by virtue of the particular
configuration
and particular arrangement of the side walls 11 and 12, the cable 45 bears
against one or the other of the walls 11 or 12 depending on the orientation of
1o the traction force exerted on the cable and depicted by the arrows 41 to
43.
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.
Figure 5 illustrates the particular extreme case of guiding a cable 55
the diameter of which is equal to dmax, the largest diameter that the device
can handle. As in the case shown in Figure 4, by virtue of the particular
configuration and particular arrangement of the side walls 11 and 12, the
cable 55 bears against one or the other of the walls 11 or 12 depending on
the orientation of the traction force exerted on the cable and depicted by the
arrows 51 to 53. As in the case of a small-diameter cable illustrated in
Figure
4, depending on the direction in which the cable enters the device, the
profile
of the wall 11 or that of the wall 12 thus guides the cable as far as the
outlet
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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.
It should be noted at this point that, due to its diameter, the cable 55 is
5 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 Figures 4 and 5, that the form
of the openings as well as the radius of curvature and the arrangement of
1o circular parts constituting the side walls are, according to the invention,
advantageously defined such that whatever the diameter of the guided cable
and whatever the orientation of the axis of the cable at the inlet of the
device,
the cable, when it is under tension, is always in contact with one of the
walls
of the device.
Consideration is now given to Figures 6 to 8 which schematically
illustrate the advantage provided by using the device according to the
invention in a spooling gear device system of a winch. The winch is
symbolized in this case by its cable drum 61 onto which a cable 62 having
variations in diameter is wound. The spooling gear system is symbolized by
the rectangle 63.
According to a known principle, illustrated in Figure 6, the spoolingof
the cable 62 is produced by the reciprocating movement of the system 63
along an axis 64 parallel to the rotational axis 65 of the cable drum 61, the
speed of movement of the system 63 depending on the speed of rotation of
the cable drum 61 and on the diameter of the cable 62. The spooling gear is
moreover equipped with a conventional guiding device 66 that forms a
guiding channel the dimensions of which are specifically adapted to a
particular cable diameter. In this way, if it is desired to be able to ensure
spooling of a cable 62 of variable diameter, it is necessary to design the
guiding channel 66 such that the cable at its largest diameter can pass
through it. However, proceeding in this manner, and unless the dimensions of
the channel are adjusted, which implies that the guiding device 66 has
moveable adjusting parts, the cable can be approximately guided at its
smallest diameter. The consequence of this guidance play is that, with the
axis of the cable at the outlet of the guiding device 66 not keeping to a
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constant direction during the winding, the cable is no longer correctly wound
onto the cable drum, which leads to the formation of non-contiguous turns as
indicated by the arrow 67.
In comparison, as is illustrated in Figures 7 and 8, the guiding device
71 according to the invention, when it is mounted on the t spooling gear
system 63 in place of the conventional guiding device, precludes such a
drawback. This is because, whether the diameter of the cable is small (cf.
Figure 7) or large (cf. Figure 8), the cable 62 is always guided perfectly so
as
to be wound onto the cable drum forming contiguous turns, the axis of the
1o cable always being approximately perpendicular to the axis of the cable
drum, whatever the position of the spooling gear system 63 on its axis of
movement 64.
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.
