Data transmission device

Abstract

The invention relates to a data transmission device (100) comprising an inner drum (101), an outer drum (102) and an optical fiber assembly (103), the inner drum (102) being concentric and free to rotate in the outer drum (101) about an axis of rotation (Ar), the inner drum (102) and the outer drum (101) each comprising an inner wall (112, 123) and an outer wall (113, 124), the optical fiber assembly (103) comprising a movable part (130) comprising a first end fixed (133) to the inner wall (112) of the outer drum (101) and a second end (134) fixed to the outer wall (124) of the inner drum (102). Figure for abstract: Figure 2

Description

Title of the invention: Data transmission device

[0001] The invention relates to data transmission devices, in particular for optronic reconnaissance and surveillance systems.

[0002] There are a large number of optronic systems in the world for aerial reconnaissance and surveillance, which are essentially dedicated aerial reconnaissance pods, laser designation and attack pods, and gyro-stabilized or non-gyro-stabilized optronic balls.

[0003] Optronic systems can be mounted in particular on airplanes, drones, balloons or helicopters.

[0004] Optronic systems generally comprise a head mounted articulated on a body. The head comprises the surveillance and targeting instruments and has a pan and tilt articulation having the capacity to pivot on two axes: horizontally (pan or roll) and vertically (tilt or elevation).

[0005] Optronic systems include a data transmission system for transferring data from the head instruments to the body, to the carrier vehicle. The quality of transmission of this data and the robustness of the system over time are crucial for optronic systems applications. One issue in this transmission is the head articulation.

[0006] For this purpose, it is known to use coaxial cables which must be carefully arranged to allow free rotation of the head while maintaining a reliable connection for data transmission.

[0007] They can in particular be arranged in loops or spirals to allow a certain flexibility when rotating the head of the system. They can also be guided by sheaths or conduits to protect them and keep them in place. It is also known to arrange them in a rotating collector.

[0008] Nevertheless, the ever-increasing quality of surveillance and targeting instruments requires an adaptation of transmission systems in order to transmit an ever-increasing quantity of information and in increasingly reduced spaces.

[0009] The invention aims to provide a reliable and robust data transmission device over time which has a large data transmission capacity and which is compact.

[0010] For this purpose, the invention relates to a data transmission device comprising an internal drum, an external drum and a fiber assembly. optical, the inner drum being concentric and free to rotate in the outer drum about an axis of rotation, the inner drum and the outer drum each comprising an inner wall and an outer wall, the optical fiber assembly comprising a movable part comprising a first end fixed to the inner wall of the outer drum and a second end fixed to the outer wall of the inner drum.

[0011] The data transmission device of the invention has the advantage of being able to wind and unwind an assembly of optical fibers. The use of an assembly of optical fibers makes it possible to obtain a greater data transmission capacity in a reduced volume compared to the transmission means of the prior art.

[0012] The transmission device of the invention can be arranged at the level of any system involving two drums rotating around the same axis and whose data must pass through said drums. The invention finds a particular application in the context of op-tronic reconnaissance and surveillance systems.

[0013] According to one embodiment of the invention, the movable part of the optical fiber assembly is in the form of at least one strip comprising an upper surface and a lower surface, the upper surface being free and the lower surface being in contact with the inner wall of the outer drum and the outer wall of the inner drum. Thus, according to this aspect of the invention, the movable part of the optical fiber assembly does not wrap around itself but folds back with the upper surface facing itself all along. Thus, the tensions on the fibers are greatly reduced and the fibers are thus better preserved for improved durability.

[0014] According to one embodiment of the invention, at least the lower part of said at least one band is smooth. This aspect of the invention makes it possible to reduce friction of the bands and therefore delays, or even avoids, their degradation due to rotations of the drums.

[0015] According to one embodiment of the invention, said at least one strip of optical fibers has reversible elastic properties. Thus, the strips of optical fibers do not tend to deform in a direction perpendicular to the winding, and are better preserved over time.

[0016] According to one embodiment, the optical fibers of said at least one strip are bonded together. This bonding allows better cohesion between the optical fibers so as to increase the resistance of the assembly to torsion forces during winding movements.

[0017] According to one embodiment, said at least one strip comprises a support on to which the optical fibers are glued.

[0018] According to one embodiment, said at least one strip of optical fibers is pressed against the internal wall of the external drum and the external wall of the internal drum.

[0019] According to one embodiment, the inner wall of the outer drum and / or the outer wall of the inner drum comprises at least one guide gutter in which the assembly of optical fibers is arranged. In particular, the inner wall of the outer drum and / or the outer wall of the inner drum comprises at least two parallel gutters separated two by two by a partition. The at least two gutters can be formed separately in the inner wall of the outer drum and / or the outer wall of the inner drum. Alternatively, a single gutter can be divided into several gutters by at least one partition in the form of an insert made of a metallic material or of a plastic material such as a fluoropolymer, for example Teflon®.

[0020] The invention also relates to an optronic reconnaissance and surveillance system comprising a data transmission device as defined previously. Brief description of the figures

[0021] The invention will be better understood on reading the following description given solely by way of example and with reference to the appended drawings in which:

[0022] [Fig.l] represents an isometric view of an optronic reconnaissance and surveillance system comprising a data transmission device according to the invention.

[0023] [Fig.2] represents an isometric view of a data transmission device according to a first embodiment of the invention.

[0024] [Fig.3] represents a top view of the device of [Fig.2].

[0025] [Fig.4] represents an isometric view of a data transmission device according to a second embodiment of the invention.

[0026] [Fig.5] represents a sectional view of the transmission device of [Fig.4] along the section axis AA. Detailed description of the invention

[0027] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Features of different embodiments may also be combined and / or interchanged to provide other embodiments;

[0028] The invention relates to a data transmission device 100 particularly adapted for an optronic reconnaissance and surveillance system 300. In [Fig.l] an example of such a reconnaissance system 300 is shown: a designation and reconnaissance pod 300 comprising a head 301 articulated by a pan and tilt joint with a body 302. The head 301 comprises measuring instruments 310 whose information must be transmitted to the body 302 through said joint. The pan and tilt joint comprises a first pivot link 303 and a second pivot link 304 arranged at 90 degrees to each other. The first pivot link 303 has a rotation limit of less than 360 degrees, in particular 240 degrees, while the second pivot link 304 has no rotation limit.The data transmission device 100 of the invention (not visible in the figure) is mounted at the level of the first pivot link 303 of the head 301 of the optronic reconnaissance and surveillance system 300.

[0029] The transmission device 100 comprises an outer drum 101, an inner drum 102 and a data transmission member in the form of an assembly of optical fibers 103.

[0030] For the remainder of the presentation, Figures 2 to 5 will be read together.

[0031] The inner drum 101 and the outer drum 102 are fitted into each other, concentric and free to rotate independently about an axis of rotation Ar, which corresponds to the pivot connection 303. The outer drum 101 comprises an internal lumen 110 in which the inner drum 102 is arranged. Thus, the inner drum 102 is circumscribed to the internal lumen 110 of the outer drum 101. The inner drum 102 comprises a body 121 articulating with the outer drum 101 by means of a bearing 105 (visible in [Fig.5]). From the body 121 of the inner drum 102 extends a tubular projection 122. The inner drum 102 comprises a central lumen 120 passing through the body 121 and the tubular projection 122 allowing the axis of rotation of the pivot connection 303 to be left free. The central lumen 110, 120 of each drum 101, 102 thus makes it possible to define an inner wall 112, 123, and an outer wall 113, 124 respectively.

[0032] The drums 101, 102 have in particular a relative rotation limit of less than 360 degrees, in particular 240 degrees. The drums 101, 102 move relatively in rotation between the maximum permitted angles.

[0033] The external drum 101 comprises a recess 111 opposite the tubular projection 122. Together, said recess 111 and the tubular projection 122 form a housing 106 in which the optical fiber assembly 103 is arranged.

[0034] The optical fiber assembly 103 comprises a movable part 130 arranged between a first fixed part 131 and a second fixed part 132. The first fixed part 131 is fixed to the internal wall 112 of the external drum 101 at the recess 111. The second fixed part 132 is fixed to the external wall 124 of the internal drum 102 at the tubular projection 122. This fixing can be done by any means, and in particular by screwing and / or by gluing. The second fixed part 132 can pass through the body 121 through an opening 125. The first 131 and the second 132 fixed parts each comprise an end fixed to the respective wall 112, 124 of the drums 101, 102 and a free end comprising an optical connection means, such as a plug 141, for the continuity of data transmission with other devices.

[0035] The movable part 130 winds and unwinds in the housing 106 following the relative rotational movements of the drums 101, 102. A first end 133 of the movable part 130 is connected to the first fixed part 131, and a second end 134 of the movable part 130 is connected to the second fixed part 132. These connections can be made in particular by means of sets of plugs. Thus, the first end 133 is fixed to the internal wall 112 of the external drum 101 by its connection to the first fixed part 131, and the second end 134 is fixed to the external wall 124 of the internal drum 102 by its connection to the second fixed part 132.

[0036] The first end 133 and the second end 134 are in particular arranged at the same height within the housing 106, so as to avoid any twisting at rest of the fixed parts 131, 132 and / or of the mobile part 130, which would be all the more accentuated during successive rotations. Such twisting may be responsible in the long term for a break in the optical fibers and the associated loss of information.

[0037] In order to guide the winding and unwinding of the optical fibers during successive rotations of the drums 101, 102, the inner wall 112 of the outer drum 101 and / or the outer wall 124 of the inner drum may comprise guide members 115, 127 (visible in FIGS. 4 and 5). Said guide members 115, 127 are in particular in the form of one or more gutters extending parallel to the direction of rotation of the drums 101, 102, or transversely to the axis Ar.

[0038] The movable portion 130 of the optical fiber assembly 103 may be in the form of one or more strips of optical fibers 135. In the embodiment shown in Figures 2 and 3, the movable portion 130 of the assembly 103 comprises a single strip of optical fibers 135. In the embodiment shown in Figures 4 and 5, the movable portion 130 of the assembly 103 comprises two strips of optical fibers 135. When several strips 135 are present, the first and second fixed parts 131, 132 may also have several parts, so that the first ends 133 and second ends 134 of each strip 135 may be at least partly connected to the same fixed part 131, 132 or each be connected to its own fixed part 131, 132. The different parts of the fixed parts 131, 132 may be fixed at different levels and locations of the internal wall 112 of the outer drum 101 and the outer wall 124 of the inner drum 102. All of the strips 135 may also be connected to the same single fixed parts 131, 132, as shown in [Fig.4]. The different strips 135 are in particular spaced apart from each other and aligned side by side, as shown in Figures 4 and 5. Alternatively, they may be superimposed on each other, with or without interposed space.

[0039] In particular, said at least one strip 135 comprises a free part 138 free from any contact arranged between a first part 139 in contact with the internal wall 112 of the external drum 101 and a second part 140 in contact with the external wall 124 of the internal drum 102. During the relative rotation of the drums 101, 102, the free part 138 has in particular the same dimensions, while the parts in contact 139, 140 will alternately shorten in favor of the elongation of the other depending on the direction of relative rotation of the drums 101, 102. Said at least one strip 135 can be adapted so that the parts in contact 139, 140 are pressed against the respective internal 112 and external 124 walls. This aim is notably achieved by cohesion of the optical fibers, as will be seen later.This aspect makes it possible to limit, or even prevent, bends at the level of these parts 139, 140, which can lead to a breakage of a part of the optical fibers and an associated loss of information.

[0040] The position of said at least one strip 135 in the housing 106 can be adapted to prevent the fibers of the strips 135 from crushing on each other during the relative rotation of the inner 101 and outer 102 drums. For this purpose, said at least one strip 135 comprises an upper surface 136 and a lower surface 137 opposite each other, the lower surface 136 being in particular the only surface in contact with the inner wall 112 of the outer drum 102 and in contact with the outer wall 124 of the inner drum 102. Thus the upper surface 136 is folded and facing itself all along the strip 135. The housing 106 is in particular adapted so that the upper surface 136 is not folded on itself during the relative rotation of the drums 101, 102. These different aspects make it possible to preserve the integrity of the optical fibers.The lower surface 136 is notably smooth in order to reduce its degradation during successive rotations of the drums 101, 102.

[0041] Said at least one strip 135 may in particular be configured so as not to bend in a direction perpendicular to the winding during rotations of the drums 101, 102. Indeed, during rotations of the drums 101, 102, said at least one strip will be pulled or pushed depending on the direction of rotation, causing torsional forces on the free part 138 and / or the parts in contact 139, 140. If the strip 135 is not strong enough in a direction perpendicular to the winding, it may bend in this direction over successive rotations. This bending may then cause at least part of the fibers to break, causing an associated loss of information.

[0042] The reduction, or even the absence, of folding at the contacting parts 139, 140 and the free part 138 can be ensured by a cohesion of the optical fibers according to the width of the strip 135 sufficient to cause reversible elastic properties. Thus, these properties allow the strip 135 to absorb the forces of the torsion, and even if the strip 135 undergoes a torsion, it returns to its original shape at the end of the action of the latter.

[0043] This cohesion can in particular be ensured by gluing the optical fibers together. The glue can be placed on the upper surface 136 and / or the lower surface 137 of the strip 135. Preferably, the glue is placed at the level of the lower surface 137, which will be in contact with the walls 112, 124 of the drums 101, 102, in order to limit possible degradation of the optical fibers.

[0044] Alternatively or in a complementary manner, the optical fibers can be fixed to a support, in particular in the form of a ribbon. In particular, the support is made of polyimide (PI) or polyethylene terephthalate (PET). In particular, the support has the same width as the width of the fibers joined together. This aspect makes it possible to reduce the chances of bending of the strip 135. The support can in particular be arranged at the level of the upper 136 or lower 137 face of the optical fibers, or else coated said fibers. Preferably, the support is arranged at least at the level of the lower surface 137 of the optical fibers, here again to limit the degradation of the latter during successive rotations.

[0045] Each strip 135 may also have its own length, or all of the strips 135 may have the same length. Of course, the length of said at least one strip 135, and of the optical fibers of the mobile part 130 in general, is adapted so as not to hinder the relative rotation of the drums 101, 102.

[0046] When several strips 135 are present, they can be separately placed in respective gutters 115, 127 parallel to each other at the level of the drums 101, 102, as visible in [Fig. 5]. In particular, two gutters are separated by a metal partition 116, 128, as shown in [Fig. 5]. This aspect makes it possible to improve the guidance of the optical fibers towards different gutters. The partition can be made of the same material as that of the gutter, in a metal material or any other material (organic for example).

[0047] The optical fibers can be of any type and in particular made of silica or plastic material. The number of fibers, in particular per strip 135, can be of any size, in particular 6, 12 or 24 fibers.

Claims

Claims

1. A data transmission device (100) comprising an inner drum (101), an outer drum (102) and an optical fiber assembly (103), the inner drum (102) being concentric and free to rotate in the outer drum (101) about an axis of rotation (Ar), the inner drum (102) and the outer drum (101) each comprising an inner wall (112, 123) and an outer wall (113, 124), the optical fiber assembly (103) comprising a movable portion (130) comprising a first end fixed (133) to the inner wall (112) of the outer drum (101) and a second end (134) fixed to the outer wall (124) of the inner drum (102).

2. A transmission device according to claim 1 wherein the movable portion (130) of the optical fiber assembly (103) is in the form of at least one strip (135) comprising an upper surface (135) and a lower surface (136), the upper surface (135) being free and the lower surface (136) being in contact with the inner wall (112) of the outer drum (101) and the outer wall (124) of the inner drum (102).

3. A transmission device according to claim 2, wherein at least the lower portion (136) of said at least one strip (135) is smooth.

4. A transmission device according to claim 2 or 3, wherein said at least one strip of optical fibers (135) has reversible elastic properties.

5. Transmission device according to one of claims 2 to 4, in which the optical fibers of said at least one strip (135) are glued together.

6. Transmission device according to one of claims 2 to 5, wherein said at least one strip (135) comprises a support on which the optical fibers are glued.

7. Transmission device according to one of claims 2 to 6, wherein said at least one strip of optical fibers (135) is pressed against the inner wall (112) of the outer drum (101) and the outer wall (124) of the inner drum (102).

8. Transmission device according to one of claims 1 to 7, wherein the inner wall (112) of the outer drum (101) and / or the outer wall (124) of the inner drum (102) comprises at least one guide gutter (115, 127) in which the optical fiber assembly (103) is arranged.

9. Transmission device according to claim 8, the inner wall (112) of the outer drum (101) and / or the outer wall (124) of the inner drum (102) comprises at least two gutters (115, 127) separated from each other by a partition (116, 128).

10. Optronic reconnaissance and surveillance systems (300) comprising a data transmission device (100) according to one of claims 1 to 9.

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