Data transmission device

Abstract

The invention relates to a data transmission device (10) comprising at least two concentric drums (101, 102) that are free to rotate about an axis of rotation (Ar), and at least two wired communication members (104), each drum (101, 102, 103) comprising a set of walls shared pairs of which form at least two concentric housings (106) such that each housing (106) comprises an internal lateral wall (160) formed by one of the drums (101, 102) and an external lateral wall (161) formed by the other or one of the other drums (101, 102), each wired data transmission member (104) being disposed in one of the housings (106), each wired communication member (104) comprising a movable part (140) disposed between a first fixed part (141) and a second fixed part (142), the first fixed part (141) being fastened to the internal wall (160) of one of the housings (106) and the second fixed part (142) being fastened to the external wall (161) of said housing (106).

Description

[0001] Title of the invention: Data transmission device

[0002] The invention relates to data transmission devices, in particular for optronic reconnaissance and surveillance systems.

[0003] 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.

[0004] Optronic systems can be mounted on aircraft, drones, balloons or helicopters.

[0005] Optronic systems generally consist of a head mounted articulated on a body. The head includes the surveillance and targeting instruments and has a pan and tilt articulation with the ability to rotate on two axes: horizontally (pan or roll) and vertically (tilt or elevation).

[0006] Optronic systems include a data transmission system that allows data to be transferred from the head instruments to the body, all the way to the carrier vehicle. The quality of this data transmission and the robustness of the system over time are crucial for optronic systems applications. One of the key issues in this transmission is the head articulation.

[0007] 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.

[0008] They can be arranged in loops or spirals to allow flexibility when rotating the system head. They can also be guided by sheaths or conduits to protect them and keep them in place. They are also known to be arranged in a rotating collector.

[0009] However, the ever-increasing quality of surveillance and targeting instruments requires adaptation of transmission systems in order to transmit an ever-increasing quantity of information and in increasingly reduced spaces. The invention aims to provide a reliable and robust data transmission device over time which has a high data transmission capacity and which is compact.

[0010] To this end, the invention relates to a data transmission device comprising:

[0011] - at least two concentric drums freely rotating around an axis of rotation, and at least two wired communication members, each drum comprising a set of walls forming in common two by two at least two concentric housings so that each housing comprises an internal side wall formed by one of the drums and an external side wall formed by the other or one of the other drums, each wired data transmission member being arranged in one of the housings, each wired communication member comprising a movable part arranged between a first fixed part and a second fixed part, the first fixed part being fixed to the internal wall of one of the housings and the second fixed part being fixed to the external wall of said housing.

[0012] The data transmission device of the invention has the advantage of being able to wind and unwind at least two optical fiber assemblies. The use of optical fiber assemblies makes it possible to obtain a greater data transmission capacity in a reduced volume compared to the transmission means of the prior art.

[0013] The transmission device of the invention can be arranged in any system involving two drums rotating around the same axis and for which data must pass through said drums. The invention finds a particular application in the context of optronic reconnaissance and surveillance systems.

[0014] According to one embodiment of the invention, the device comprises at least three concentric drums.

[0015] In particular, at least two of the housings comprise a common side wall, where at least two wired communication members each comprise one of their fixed parts fixed to said or one of said common walls, and where said fixed parts fixed to said or one of said common walls are connected to each other by a connecting member. According to one embodiment of the invention, the wired communication means comprise at least one assembly of optical fibers and / or at least one assembly of copper cables.

[0016] In particular, the wired communication means (104) comprise at least one assembly of optical fibers whose movable part 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 and the outer wall of one of the housings. Thus, according to this aspect of the invention, the movable part of the assembly of optical fibers does not wind on itself but folds 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.

[0017] According to one embodiment of the invention, at least the lower part of said at least one belt is smooth. This aspect of the invention makes it possible to reduce friction of the belts and therefore delays, or even avoids, their degradation due to the rotations of the drums.

[0018] 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.

[0019] According to one embodiment, the optical fibers of said at least one strip are bonded together. This bonding allows for better cohesion between the optical fibers so as to increase the resistance of the assembly to torsional forces during winding movements.

[0020] According to one embodiment, said at least one strip comprises a support on which the optical fibers are glued.

[0021] According to one embodiment, said at least one strip of optical fibers is pressed against the internal wall and the external wall of one of the housings.

[0022] The invention also relates to an optronic reconnaissance and surveillance system comprising a data transmission device as defined previously.

[0023] Brief description of the figures The invention will be better understood from reading the following description given solely by way of example and with reference to the appended drawings in which:

[0024] Figure 1 represents an isometric view of an optronic reconnaissance and surveillance system comprising a data transmission device according to the invention.

[0025] Figure 2 represents an isometric view of a data transmission device according to a first embodiment of the invention.

[0026] Figure 3 represents a sectional view along axis AA of the device of Figure 2.

[0027] Figure 4 shows a sectional view of a data transmission device according to a second embodiment of the invention.

[0028] Figure 5 shows an isometric view of a data transmission device according to a third embodiment of the invention.

[0029] Figure 6 represents a sectional view along the BB axis of the device of Figure 5.

[0030] Figure 7 shows a sectional view of a data transmission device according to a fourth embodiment of the invention.

[0031] Detailed description of the invention

[0032] 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.

[0033] The invention relates to a data transmission device 10 particularly suitable for an optronic reconnaissance and surveillance system 30. Figure 1 shows an example of such a reconnaissance system 30 comprising a designation and recognition pod 30 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 10 of the invention (not visible in FIG. 1) is notably mounted at the level of the first pivot link 303 of the head 301 of the optronic reconnaissance and surveillance system 30.

[0034] The transmission device 10 comprises at least two drums 101, 102, 103 as well as at least two wired communication members 104. The device 10 comprises an upper surface 107 and a lower surface 108 opposite each other and transverse to the axis A r . The terms “upper” and “lower” do not have in the present description a limit of spatial orientation of the device 10 or of any element composing it, but simply a notion of spatial opposition. The communication members 104 pass through the device 10 on either side in the direction of the axis A rby at least one opening 109 arranged at the level of the upper surface 107 and at least one opening 109 arranged at the level of the lower surface 108.

[0035] The drums 101, 102, 103 are arranged concentrically and freely rotating independently around an axis of rotation A. r , which here corresponds to the pivot connection 303. In the embodiment shown in Figures 1 and 2, two drums are present. In the embodiments shown in Figures 4-6, three drums are present. Whatever the embodiment, the device always comprises an external drum 101, an internal drum 101 and optionally one or more intermediate drums 103.

[0036] The drums 101, 102, 103 have in particular a relative rotation limit of less than 360 degrees, in particular 240 degrees. This limitation is obtained by any means and in particular by a stop (not shown) intended to cooperate with the surrounding elements of the system in which the device 10 is installed or with the adjacent drum(s) 101, 102, 103. The drums 101, 102, 103 move relatively in rotation between the maximum authorized angles.

[0037] The inner drum 102 and outer drum 101 will first be described using figures 2-3. In the embodiment shown, the outer drum 101 extends around the inner drum 102 which is in turn circumscribed to the outer drum 101. The inner drum 102 comprises a body 122 articulated with the pivot connection 303. The outer drum 101 comprises a body 111 which can be articulated directly with the pivot connection 303 or with the inner drum 102, in particular via a bearing 105. The body 122 of the inner drum 102 comprises in particular a tubular projection 123 extending along the axis A r and crossed by a central light 121 in which the pivot connection 303 is inserted.

[0038] We will now turn to Figures 4-6 which illustrate three embodiments comprising an intermediate drum 103. An intermediate drum 103 can, like the external drum 101, be articulated directly with the pivot connection 303 or with at least other drums 101, 102, 103, in particular via one or more bearings 105. Thus, as can be seen in Figures 4 and 6, the intermediate drum 103 can be articulated with the internal drum 102 and the external drum 103 (Figure 4), as well as with only one of the two (Figure 6). Furthermore, the difference between the second and the third and fourth embodiments shown in these figures lies in the configuration of the communication members 104, described in detail below. For the remainder of the description, all of Figures 2-6 will be read together.

[0039] The different drums 101, 102, 103 each comprise a set of walls 110, 120, 130. The configuration of these sets of walls 110, 120, 130 makes it possible to form in common two by two at least two housings 106, each intended to receive at least one of the communication members 104. Each housing 106 therefore defines a space where the communication members 104 will be able to wind and unwind during the respective rotations of the drums 101, 102, 103 around the axis A. r The openings 109 of the upper and lower surfaces 107, 108 of the device 10 thus open onto the housings 106 for the passage of the communication members 104.

[0040] The housings 106 are arranged concentrically around the axis A r , and in particular around the tubular projection 123 of the internal drum 102.

[0041] Each housing 106 is delimited by side walls, namely an internal wall 160 and an external wall 161, one of which belongs to one of the drums 101, 102, 103 and the other to another drum 101, 102, 103. By "internal wall" we mean the wall of the housing 106 which is closest to the axis A r , and in particular of the central light 121. In contrast, the term “external wall” means the wall of the housing 106 which is furthest from the axis A r and in particular of the central light 121. The internal and external walls 160, 161 of the housings 106 therefore extend along the axis A r and follow one another transversely to axis A rEach housing 106 may comprise internal and external walls 160, 161 distinct from the other housings 106, or at least two housings may share one of the side walls 160, 161, then called a common wall 165. Each drum 101, 102, 103 forms a wall 160, 161 of at least one of the housings 106. Thus a drum 101, 102, 103 may form several walls 160, 161 but of different housings 106. In addition to the internal and external walls 160, 161, each housing 106 comprises a first transverse wall 162 and / or a second transverse wall 163, the first and second transverse walls 162, 163 being opposite each other and connected to the internal and external walls 160, 161. A wall 162, 163 may in particular comprise the upper surface 107 or lower surface 108 of the device 10.The first transverse wall 162 and / or the second transverse wall 163 of a housing 106 may be formed by different elements of the device 10, namely a wall 110, 120, 130 of a drum 10, 102, 103, a bearing 105, or a combination of these. The housing 106 comprises at least one opening 164 for the passage of the communication members 104 which is arranged in a wall 110, 120 or 130 forming at least in part said wall 162, 163, as shown in FIG. 2. For obvious operational reasons, the wall 110, 120, 130 in which the opening 164 is arranged belongs to the drum 101, 102, 103 forming the wall 160, 161 to which the communication member(s) 104 passing through the opening 164 are fixed. The cooperation between the communication members 104 and the drums 101, 102, 103 is described in detail below.The housing 106 may be fully open on one side so that it does not comprise a first transverse wall 162 or a second transverse wall 163 but an opening 164 instead, as can be seen for example in Figures 2 to 6. The openings 164 open onto the opening(s) 100 or correspond to these openings 100.

[0042] When an intermediate drum 103 comprises a wall 130 forming a common wall 165 with two housings 106, it can also carry a connecting member 150 connecting two communication members 104, as shown in Figures 5-7. The connecting member 150 is in particular connected to one of the fixed parts 141, 142 of each communication member 104, or to their movable part 140, these fixed parts 141, 142 and movable parts 140 being described in detail below. The connecting member 150 is in particular in the form of at least one assembly of optical fibers and / or at least one assembly of copper cables passing through or going around the common wall 165, as shown in Figures 5-6. This aspect of the invention advantageously makes it possible to increase tenfold the possible winding and unwinding angle of the communication members 104 by connecting them together.Indeed, in a first housing 106, a first communication member 104 arranged therein can be wound / unwound at a certain angle, then a second member 104 arranged in a second adjacent housing 106 and connected to the first can take over the winding / unwounding. Of course, the different drums 101, 102, 103 forming the adjacent housings 106 in which the different communication members 104 connected to each other are in motion, are coordinated with each other. This coordination can be achieved by any means and in particular using sets of stops, and makes it possible to prevent the rotation of one of the drums 101, 102, 103 from pulling on a communication member 104 arranged in a housing 106 that it does not form, and from causing it to tear.

[0043] The communication members 104 may comprise at least one assembly of optical fibers and / or at least one assembly of copper cables.

[0044] The communication members 104 each comprise a movable part 140 arranged between a first fixed part 141 and a second fixed part 142. The first fixed part 141 is fixed to the internal wall 160 of a housing 106, and the second fixed part 142 is fixed to the external wall 161 of said housing 106. This fixing can be done by any means, and in particular by screwing and / or by gluing. As seen previously, the first fixed part and the second fixed part 141, 142 can pass through the first transverse wall 162 and the second transverse wall 163 respectively through at least one opening 164. The first 141 and the second 142 fixed parts each comprise in particular an end fixed to the wall 160, 161 of the housing 106 and a free end comprising in particular a connection means, such as a plug 149, for the continuity of data transmission with other devices.

[0045] The movable part 140 winds and unwinds in the housing 106 following the relative rotational movements of the drums 101, 102, 103. A first end 143 of the movable part 140 is connected to the first fixed part 141, and a second end 144 of the movable part 140 is connected to the second fixed part 142. These connections can be made by any means and in particular by means of sets of plugs. Thus, the first end 143 is fixed to the wall 160, 161 of the housing 106 by its connection to the first fixed part 141, and the second end 144 is fixed to the wall 160, 161 of the housing 106 by its connection to the second fixed part 142.

[0046] The first end 143 and the second end 144 of the mobile part 140 are in particular arranged at the same height within the housing 106, so as to avoid any twisting at rest of the fixed parts 141, 142 and / or of the mobile part 140, which would be all the more accentuated during successive rotations. Such twisting may be responsible in the long term for damage to the communication members and the associated loss of information.

[0047] In order to guide the winding and unwinding of the optical fiber assemblies 103 during successive rotations of the drums 101, 102, the internal wall 160 and / or the external wall 161 of at least one of the housings 106 may comprise guide members 115, 127, as shown in Figures 3-6. Said guide members 115, 127 are in particular in the form of one or more gutters parallel to the direction of rotation of the drums 101, 102, or transversely to the axis Ar .

[0048] The movable part 140 of at least one of the communication members 103 may be in the form of one or more strips 145, as shown in FIGS. 2 to 7. When several strips 145 are present, the first and second fixed parts 141, 142 of a communication member 103 may also have several parts, so that the first ends 143 and second ends 144 of each strip 145 may be at least partly connected to the same fixed part 141, 142 or each be connected to its own fixed part 141, 142. The different parts of the fixed parts 141, 142 may be fixed at different levels and locations of the internal wall 160 and the external wall 161 of the housing 106, but are preferably fixed at the same level for the same strip 145. All of the strips 145 may also be connected to the same single fixed parts 141, 142, as shown in Figure 2.The different strips 145 are in particular spaced apart from each other and aligned side by side along the walls 160, 161, as shown in this figure. Alternatively, they can be superimposed on each other, with an intermediate space in the opposite direction.

[0049] In particular, said at least one strip 145 comprises a free part 146 free from any contact arranged between a first part 147 in contact with the internal wall 160 of the housing 106 and a second part 148 in contact with the external wall 161 of the housing 106. During the relative rotation of the drums 101, 102, the free part 146 has in particular the same dimensions, while the parts in contact 147, 140 will alternately shorten in favor of the lengthening of the other depending on the direction of relative rotation of the drums 101, 102.

[0050] Within an assembly 103, each strip 145 may have its own length, or all of the strips 145 may have the same length. Of course, the length of said at least one strip 145 is adapted so as not to hinder the relative rotation of the drums 101, 102.

[0051] When several strips 145 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 shown in Figures 3-6. In particular, two gutters 115, 127 are separated by a partition 118, 123. 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 metallic material or any other material (organic for example). According to one embodiment, said at least one strip 145 can be configured so that the contacting parts 147, 148 are pressed against the respective internal 160 and external 161 walls. This aspect makes it possible to limit, or even prevent, folds at the level of these parts 147, 148, which can cause damage to the communication organs and an associated loss of information.

[0052] The position of said at least one strip 145 in the housing 106 can be configured so that it does not roll up on itself and does not risk being damaged by crushing during the relative rotation of the inner 101 and outer 102 drums. For this purpose, said at least one strip 145 comprises an upper surface and a lower surface opposite each other, the lower surface being in particular the only surface in contact with the inner wall and the outer wall 160, 161 of the housing 106. Thus the upper surface is folded and facing itself all along the strip 145. The housing 106 is in particular adapted so that the upper surface of the strip 145 is not folded back 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 is notably smooth in order to reduce its degradation during successive rotations of the drums 101, 102.

[0053] Said at least one strip 145 may in particular be configured so as not to bend in a direction perpendicular to the winding during the rotations of the drums 101, 102. Indeed, during the 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 146 and / or the parts in contact 147, 148. If the strip 145 is not strong enough in a direction perpendicular to the winding, it may bend in this direction over the successive rotations. This bending may then cause damage to the communication members, resulting in an associated loss of information.

[0054] In the context of optical fiber assemblies, the reduction, or even the absence, of folding at the contacting parts 147, 148 and the free part 146 as well as the plating of the contacting parts 147, 148 against the respective inner 160 and outer 161 walls can be ensured by a cohesion of the optical fibers according to the width of the strip 145 which is sufficient to cause reversible elastic properties. Thus, these properties allow the strip 145 to absorb the forces of torsion, and even if the strip 145 undergoes a torsion, it returns to its original shape at the end of the action of the latter.

[0055] This cohesion can in particular be ensured by gluing the optical fibers together. The glue can be placed on the upper surface and / or the lower surface of the strip 145. Preferably, the glue is placed at the level of the lower surface, which will be in contact with the walls 160, 161, of the housings 106, in order to limit possible degradation of the optical fibers.

[0056] Alternatively or additionally, the optical fibers may be attached 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 145. The support may in particular be arranged at the upper or lower face of the optical fibers, or else coated said fibers. Preferably, the support is arranged at least at the lower surface of the optical fibers, here again to limit the degradation of the latter during successive rotations.

[0057] Optical fibers can be of any type, including silica or organic material. The number of fibers, including per 145 band, can be of any size, including 6, 12, or 24 fibers.

Claims

Claims 1. Data transmission device (10) comprising - at least two drums (101, 102, 103) concentric and free to rotate around an axis of rotation (A) r), and at least two wired communication members (104), each drum (101, 102, 103) comprising a set of walls (110, 120, 130) forming in common two by two at least two concentric housings (106) so that each housing (106) comprises an internal side wall (160) formed by one of the drums (101, 102, 103) and an external side wall (161) formed by the other or one of the other drums (101, 102, 103), each wired data transmission member (104) being arranged in one of the housings (106), each wired communication member (104) comprising a movable part (140) arranged between a first fixed part (141) and a second fixed part (142), the first fixed part (141) being (143) fixed to the internal wall (160) of one of the housings (106) and the second fixed part (142) being fixed to the external wall (161) of said housing (106).

2. Transmission device according to claim 1, comprising at least three concentric drums (101, 102, 103).

3. Transmission device according to claim 2, wherein at least two of the housings (106) comprise a common side wall (165), where at least two wired communication members (104) each comprise one of their fixed parts (141, 142) fixed to said or one of said common walls (165), and where said fixed parts (141, 142) fixed to said or one of said common walls (165) are connected to each other by a connecting member (150).

4. Transmission device according to one of claims 1 to 3, in which the wired communication means (104) comprise at least one assembly of optical fibers and / or at least one assembly of copper cables.

5. Transmission device according to claim 4, in which the wired communication means (104) comprise at least one assembly of optical fibers whose movable part (140) is in the form of at least one strip (145) comprising a first surface and a second surface opposite each other, the first surface (145) being free and the second surface being in contact with the internal wall (160) and the external wall (161) of one of the housings (106).

6. Transmission device according to claim 5, wherein said at least one strip of optical fibers (145) has reversible elastic properties.

7. Transmission device according to claim 5 or 6, wherein the optical fibers of said at least one strip (145) are glued together.

8. Transmission device according to one of claims 5 to 7, wherein said at least one strip (145) comprises a support on which the optical fibers are glued.

9. Transmission device according to one of claims 5 to 8, in which said at least one strip of optical fibers (145) is pressed against the internal wall (160) and the external wall (161) of one of the housings (106).

10. Optronic reconnaissance and surveillance systems (30) comprising a data transmission device (10) according to one of claims 1 to 9.

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