Device for measuring a force on a traction device of a towed antenna arrangement

Abstract

A device (20) for measuring a tensile force (22) on a traction means (24) for a towed antenna arrangement is disclosed. The device comprises the traction means (24), a curved shaped piece (26), a fixing element (28), and a strain sensor (30). The fixing element (28) is designed to fasten the shaped piece (26) to the traction means (24) in such a way that the traction means (24) also undergoes a curvature due to the curvature of the shaped piece (26). The strain sensor (30) is designed to detect a curvature of the shaped piece (26) or of the traction means (24) that changes due to a tensile force on the traction means.

Description

[0001] The invention relates to the measurement of tensile forces acting on a traction device of a towed antenna.

[0002] Towed antennas are used, among other things, to locate objects underwater. The towed antenna itself is usually designed as a passive sonar. This means that the towed antenna usually receives underwater sound and does not emit underwater sound signals. To operate active sonar with towed antennas, an additional underwater sound transducer is often used, mounted either in a towed body or on board a watercraft, to emit underwater sound signals, the reflections of which the towed antenna can receive. The towed antenna is usually connected to the towing watercraft by means of a traction device. Furthermore, there is at least one (further) traction device within the towed antenna to absorb the tensile forces acting on the towed antenna. The underwater sound transducers are also usually attached to the traction device within the towed antenna.

[0003] When the vessel is moving, large forces act on the towed antenna, i.e. both the traction device connecting the towed antenna to the towing vessel and the traction device(s) within the towed antenna. In order to measure these forces, for example in order to be able to reduce the speed in the event of excessive tensile forces before a traction device breaks, the tensile forces acting on the traction device(s) are measured. Until now, this required cutting the traction devices and installing a force sensor into the traction device as part of the traction device. This force sensor then had to be firmly connected to both open ends of the cut traction device in order to reassemble the traction device. This meant that the traction cables or belts within a towed sonar arrangement previously had to be extensively modified in order to integrate a tensile force sensor for the towing forces.This requires cutting the traction device, splicing the open ends, and reconnecting them using a suitable force sensor. The process of integrating a conventional force sensor into a towed sonar array is complex and weakens the structure: Every interruption represents a potential point of failure in the traction device. Furthermore, the use of conventional force sensors is difficult or even impossible due to their size, especially in towed sonar systems with small diameters.

[0004] The object of the present invention is therefore to create an improved concept for traction means, in particular the measurement of tensile forces on a traction means.

[0005] This object is achieved by the subject matter of the independent patent claims. Further advantageous embodiments are the subject matter of the dependent patent claims.

[0006] Embodiments show a device for measuring a force on a traction device for a towed antenna arrangement. The device can also be referred to as a traction device arrangement. The device has the traction device, a curved shaped piece, a fixing element and a strain sensor. The traction device can be a rope or a belt. A rope has a substantially round cross-section, whereas a belt has a cross-section that deviates from a round cross-section, i.e. the cross-section of a belt has different diameters in two mutually perpendicular directions. For example, the belt can have a substantially rectangular cross-section, whereby “substantially” refers, for example, to the fact that the rectangle can have rounded corners. The shaped piece is curved if at least one surface is not in a plane.In other words, the curved fitting can be either bent (without discontinuities in the curvature) or angled (with discontinuities in the curvature).

[0007] The fixing element is designed to fasten the shaped piece to the tensioning means in such a way that the tensioning means also undergoes a curvature due to the curvature of the shaped piece. This means that when the tensioning means is tensioned, it is not linearly stretched but rather takes on a shape that deviates from the linear expansion at the point where the shaped piece is arranged. The fixing element can, for example, be screwed into the shaped piece in order to fasten the shaped piece to the tensioning means. The strain sensor is designed to detect a changing curvature of the shaped piece or of the tensioning means due to a tensile force on the tensioning means. This means that the tensile force changes the shape of the shaped piece and the shape of the tensioning means at this position. This change in shape (either of the tensioning means or of the shaped piece) can be measured by the strain sensor.

[0008] The strain sensor can be, for example, a strain gauge or an optical strain sensor, or they can comprise the same if, for example, multiple sensors, especially different types of sensors, are used. Optical strain sensors, for example, use a fiber Bragg grating for strain measurement.

[0009] The idea is to determine the force acting on the traction device directly at the traction device itself, without having to separate it. To do this, a section of the traction device is guided out of its original straight path using the shaped piece, so that a tensile force acts on the traction device such that the traction device returns to its original shape. The shaped piece counteracts the tensile force but deforms due to the tensile force. The deformation can be measured using the strain sensor. A suitable shaped piece could be a piece of sheet metal, for example, which, together with the fixing element, deforms the traction device so that the belt or rope causes an elastic deformation of the sheet metal when subjected to tensile stress. If the sheet metal is suitably designed, this deformation is proportional to the tensile force in the rope and can be evaluated using the strain sensor.

[0010] This results in a very compact sensor, ie with a short overall length and low overall height, which can also be integrated into arrays with a small diameter (ie, for example, a diameter of less than 10 cm, preferably less than 7 cm, more preferably less than 4 cm) and only short free sections between the waterborne sound transducers and other electronic components.

[0011] Furthermore, the described principle prevents weakening of the tension elements of the towed antenna array. Furthermore, subsequent installation or replacement of sensors at any location in the towed antenna array is possible.

[0012] In exemplary embodiments, the traction means is part of a towed antenna of the towed antenna arrangement. In particular, the traction means, in particular a belt, has a plurality of openings for attaching electrical components to the traction means. The openings can be arranged at regular intervals in the traction means. Electrical components are, for example, water-borne sound transducers, analog-digital converters, amplifiers, or the like. To accommodate the electrical components, corresponding (further) shaped pieces can be used in the towed antenna, which are connected to the traction means and accommodate the electrical components in order to connect them to the traction means. Preferably, the fixing element uses an unused opening of the plurality of openings to connect the (original) shaped piece (for deformation of the traction means) to the traction means. An opening can also be referred to as a hole. That is,The presented pressure sensor can be integrated into the traction device without having to separate the traction devices, especially the traction belts of modern towed antennas.

[0013] The towed antenna preferably has a casing in which the traction means is guided. The casing can form the transition between the towed antenna and the surrounding area of ​​the towed antenna. The casing can preferably be filled with a liquid. This allows, for example, the up- or down-lift of the towed antenna to be adjusted and the components of the towed antenna can be protected from corrosion and electrical arcing.

[0014] Additionally or alternatively, the traction device is designed to connect the towed antenna of the towed antenna arrangement to a watercraft in order to pull the towed antenna. Thus, a tensile force on the traction device connecting the watercraft to the towed antenna can also be determined.

[0015] In exemplary embodiments, the shaped piece is configured and connected to the traction means such that only a central fixation of the traction means on the shaped piece is necessary. In this case, the shaped piece is attached to the traction means with a single, i.e., exactly one, fixation element. This enables very simple attachment of the shaped piece. Alternatively, the arrangement is configured such that the traction means is fixed at the two distal ends of the shaped piece.

[0016] It has proven advantageous to mount the strain sensor on the side of the fitting facing away from the traction device.

[0017] Depending on the shape of the fitting and the side of the fitting to which the strain sensor is applied, the bending of the fitting results in a compression of the strain sensor or an extension of the strain sensor when a tensile force is applied to the tension member. In other words, the fitting is bent by the acting force (from its pre-bent shape to a straight shape), resulting in compression on one side of the fitting and extension on the other. The strain sensor can, in principle, be bonded to either side and therefore experiences either compression or extension.

[0018] Preferred embodiments of the present invention are explained below with reference to the accompanying drawings. Fig. 1: a schematic sectional view of a device for measuring a force on a traction means for a towed antenna arrangement, wherein Fig. 1a, Fig. 1b and Fig. 1c shows different designs of fittings of the device; Fig. 2: a schematic perspective view of the device in an embodiment.

[0019] Before exemplary embodiments of the present invention are explained in more detail below with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that the description of these elements shown in different exemplary embodiments is interchangeable or can be applied to one another.

[0020] Fig. 1 shows in Fig. 1a, Fig. 1b, Fig. 1c and Fig. 1d each show a schematic sectional view of a device 20 for measuring a tensile force 22 on a traction device 24 for a towed antenna arrangement. In addition to the traction device 24, the device comprises a curved shaped piece 26, a fixing element 28 and a strain sensor 30. The fixing element 28 fastens the shaped piece 26 to the traction device 24 in such a way that the traction device 24 also undergoes a curvature due to the curvature of the shaped piece 26. It should be noted that the curvature is shown very prominently for better explanation and that even small curvatures can be sufficient to detect the tensile force. In particular, small elastic operating deformations are advantageous because in this range of slight geometric shape changes (i.e. deformations or bends), there is an approximately linear relationship between the acting force and the output signal of the strain sensor.The strain sensor 30 now detects a changing curvature of the shaped piece 26 or of the pulling means 24 due to a tensile force 22 on the pulling means 24. In the figures, the strain sensor is arranged on the shaped piece 26 in each case, so that the changed curvature of the shaped piece 26 is measured.

[0021] Fig. 1a now shows a section of a trailing antenna 32. Two traction means 24, 24', in particular two belts, with the devices 20, 20' for strain measurement run in the trailing antenna 32. The shaped pieces 26, 26' are arranged on the traction means 24, 24' by means of the fixing elements 28, 28' in such a way that the tensile force 22 on the traction means 24 causes a compression of the surface of the shaped piece 26, 26'. This means that each traction means 24, 24' is evaluated by a strain sensor. In addition to the devices 20, 20', (further) shaped pieces 34, 34' are arranged on the traction means 24, 24'. Electrical components can be (mechanically) connected to the traction means 24, 24' by means of the shaped pieces 34, 34'.

[0022] Fig. Figure 1b shows an embodiment of strain measurement using an alternative shaped piece. The shaped piece 26 is attached to the tension member 24 by means of a plurality of fixing elements 28a, 28b, etc. A total of 11 fixing elements are shown, purely as an example. Thus, the shaping of the tension member occurs continuously over the entire length of the shaped piece 34. A tensile force 22 causes a bending of the previously straight shaped piece 26 on the side facing away from the tension member. By using the plurality of fixing elements, the tension member experiences an almost continuous curvature, which benefits the strength and service life of the tension member.

[0023] Fig. 1c shows an alternative embodiment of the continuous shaping of the traction means 24 over the entire length of the shaped piece 26. The traction means 24 has a groove 36 whose shape corresponds to the desired shape of the traction means. The traction means 24 is inserted into this groove 36. The traction means is preferably fixed in the groove by means of one or more fixing elements 28. This prevents the traction means 24 from slipping out of the groove 36; preferably, the shaped piece 26 is then also fixedly connected to the traction means 24. A fixed connection of the shaped piece to the traction means can be achieved, for example, by a fixing element that is guided through the shaped piece and the traction means. The fixing element preferably penetrates the traction means at a position with an existing opening.

[0024] Fig. 1d shows an embodiment similar to the embodiment of Fig. 1 b and Fig. 1c. However, the curvature of the fitting 30 is chosen differently. In combination with two illustrated fixing elements 28a, 28b, this results in the fitting being connected to the traction device at two discrete points. However, the course of the traction device does not follow the course of the fitting over the entire length of the fitting 26. However, the installation effort is less than in the embodiment of Fig. 1b. Overall, the course of the traction device is similar to Fig. 1b and Fig. 1c selected.

[0025] In the examples from Fig. 1b and Fig. 1c it is clear that more than one fixing element is required to connect the shaped piece 30 to the traction means 24. Furthermore, it should be noted that in Fig. 1b and Fig. 1c only one traction device of the representation Fig. 1a. This is also how the towing device that connects the towed antenna to the watercraft can be mounted.

[0026] Fig. 2 shows an embodiment of the device 20 in a schematic perspective view, wherein the embodiment of the representation of the lower traction means 24' from Fig. 1a is similar.

[0027] Although some aspects have been described in connection with a device, it should be understood that these aspects also represent a description of the corresponding method, so that a block or component of a device can also be understood as a corresponding method step or as a feature of a method step. Analogously, aspects described in connection with or as a method step also represent a description of a corresponding block, detail, or feature of a corresponding device.

[0028] The above-described embodiments are merely illustrative of the principles of the present invention. It is understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein. List of reference symbols: 20 Device 22 traction force 24 traction devices 26 curved fitting 28 Fixing element 30 strain sensor 32 towed antenna 34 additional fitting 36 grooves

Claims

[1] Device (20) for measuring a tensile force (22) on a traction means (24) for a towed antenna arrangement, having the following features: - the traction means (24); - a curved shaped piece (26); - a fixing element (28); - a strain sensor (30); - wherein the fixing element (28) is designed to fasten the shaped piece (26) to the traction means (24) in such a way that the traction means (24) also undergoes a curvature due to the curvature of the shaped piece (26); and - wherein the strain sensor (30) is designed to detect a curvature of the shaped piece (26) or of the traction means (24) which changes due to a tensile force on the traction means. [2] Device (20) according to claim 1, wherein the traction means (24) is a rope. [3] Device (20) according to claim 1, wherein the traction means (24) is a belt. [4] Device (20) according to one of the preceding claims, wherein the strain sensor (30) comprises or consists of a strain gauge. [5] Device (20) according to one of the preceding claims, wherein the strain sensor (30) comprises or consists of an optical sensor. [6] Device (20) according to one of the preceding claims, wherein the traction means (24) is part of a towed antenna (32) of the towed antenna arrangement. [7] Device (20) according to claim 6, wherein the traction means (24), in particular at regular intervals, has a plurality of openings for fastening electrical components to the traction means (24), wherein the fixing element (28) uses an unused opening of the plurality of openings to connect the shaped piece (26) to the traction means (24). [8] Device (20) according to one of claims 6 or 7, wherein the towed antenna has a casing in which the traction means is guided. [9] Device (20) according to claim 8, wherein the jacket is filled with a liquid. [10] Device (20) according to one of the preceding claims, wherein the pulling means (24) is designed to connect the towed antenna of the towed antenna arrangement to a watercraft in order to pull the towed antenna. [11] Device (20) according to one of the preceding claims, wherein the shaped piece (26) is designed and connected to the traction means (24) in such a way that the strain sensor (30) detects a compression of the shaped piece (26). [12] Device (20) according to one of the preceding claims, wherein the shaped piece (26) is designed and connected to the traction means (24) in such a way that the strain sensor (30) detects an extension of the shaped piece (26). [13] Device (20) according to one of the preceding claims, wherein the strain sensor is applied to a side of the shaped piece facing away from the traction means. [14] Device (20) according to one of the preceding claims, wherein the shaped piece is attached to the traction means with a single fixing element.

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