Device and method for measuring cable force

Abstract

The present application discloses a device and method for measuring the tension of a cable, and relates to the engineering technology field of cable system bridges. The device comprises: two cable hoops, which are used to be arranged on the cable at intervals; at least one measuring assembly, which comprises a data transmitter, a first length measuring device, and a first rigid rod, a second length measuring device, an elastic tensioning member, and a second rigid rod connected in sequence; the first length measuring device comprises a fixed portion and a measuring portion installed on the fixed portion, the fixed portion is arranged on the first rigid rod, and the measuring portion is connected to a cable hoop after passing through a ring buckle on the second rigid rod; the free end of the first rigid rod is connected to another cable hoop; the measuring accuracy of the second length measuring device is higher than that of the first length measuring device; the data transmitter is connected to both the first length measuring device and the second length measuring device. In the present application, the device is arranged on the cable, and is not limited to the tensioning stage of the cable during construction, and can measure the length of the cable in the later maintenance stage of the cable to calculate the tension of the cable.

Description

Technical Field

[0001] The present application relates to the technical field of cable system bridge engineering, and in particular to a device and method for measuring cable force. Background Art

[0002] With the economic development of society, the construction of large beam bridges has gradually increased. Among them, cable-stayed bridges, suspension bridges, tie-arch bridges and other large-span cable-stayed bridges with a span of hundreds of meters or even thousands of meters also play a key role. The cables, ropes and tie rods in the cable-stayed bridges are important load-bearing components. Whether the internal forces of these load-bearing components are within a reasonable range directly affects the overall force and linear smoothness of the cable-stayed bridges. Therefore, accurate measurement of the cable forces of these load-bearing components is a necessary operation in bridge construction or daily maintenance.

[0003] In the prior art, there are various ways to measure cable tension, such as: jack pressure gauge measurement method, pressure sensor measurement method, resistance strain gauge measurement method, magnetic flux measurement method, vibration frequency measurement method, etc. However, the above cable tension measurement methods all have certain limitations.

[0004] Among them, the jack pressure gauge measurement method directly uses the cable tensioning jack equipped with a precision pressure gauge or hydraulic sensor to measure the cable force. It has the advantages of simple and direct detection, but this method is only applicable to the cable tensioning stage of construction, and the jack is frequently used and the calibration curve error is difficult to control, so the test accuracy is not high.

[0005] The pressure sensor measurement method is to place a pressure sensor on the anchor end of the cable during bridge construction, and measure the cable tension by measuring the pressure applied to the pressure sensor. However, the pressure sensor is expensive, has a large mass, and is inconvenient to construct, so this method is not often used to measure cable tension.

[0006] The resistance strain gauge method is an early method of measuring cable tension. It directly sticks strain gauges on the cables, measures the strain, and then directly calculates the cable tension based on the relationship between strain and stress. However, strain gauges are not easy to protect and have a low survival rate, so they are rarely used at present.

[0007] The magnetic flux measurement method is based on the principle of electromagnetic induction. When current is passed through the magnetic flux sensor, a magnetic field will be generated in the longitudinal direction of the cable. The magnetic field of the magnetized cable will produce an induced electromotive force on the sensor. The induced electromotive force is sensitive to the internal stress of the cable. By calibrating this relationship, the stress change of the cable can be monitored. The advantage of this method is that except for magnetizing the cable, it does not affect any mechanical and physical properties of the cable. The disadvantage is that it must be calibrated on-site and is greatly affected by temperature fields and electromagnetic fields. At the same time, the measurement cost is also high.

[0008] The vibration frequency measurement method is to place acceleration sensors on the cables, obtain the vibration frequency of the cables through artificial or environmental excitation, and then use the simplified formula of vibration frequency and cable force to approximate the cable force. This method is currently a common method used in the measurement of bridge cable force, but it also has limitations. Specifically, this method is to limit the hinges at both ends of the cable, which is not applicable to short cables or cables with large stiffness; secondly, due to the limitations of actual application conditions, acceleration sensors are often set close to the anchor end, which can easily cause the fundamental frequency of long cables to be unable to be directly measured, thus affecting the accuracy of the test structure; thirdly, the measurement of this method is greatly affected by the wind and rain environment, and the accuracy of the test results is not high in bad weather; at the same time, the test data requires a large amount of work for post-processing, which is also unfavorable for monitoring applications during the operation period. In addition, for cables with complex and convenient conditions such as shock absorbers installed, the theoretical formula analysis and calculation are complex.

[0009] It can be seen that it is very necessary to develop a method that can monitor the cable over a long period of time to accurately measure the cable force. Summary of the invention

[0010] The embodiments of the present application provide a device and method for measuring the tension of a cable. The device provided by the embodiments of the present application can use two length measuring devices to accurately obtain the length between two cable clamps on the cable. At the same time, the cable clamp is normally installed on the cable and is not limited to the cable tensioning stage of construction. The length of the cable can be measured in the later maintenance stage of the cable for calculating the tension of the cable. The method based on the above-mentioned device provided by the embodiments of the present application calculates that the cable tension is less affected by environmental factors and is simple to calculate, so the cable tension can be accurately obtained.

[0011] In a first aspect, an embodiment of the present application provides a device for measuring cable force, the device comprising:

[0012] Two cable hoops, the two cable hoops are used to be arranged on the cable at intervals;

[0013] At least one measuring assembly, the measuring assembly comprising a data transmitter, a first length measuring device, and a first rigid rod, a second length measuring device, an elastic tensioning member, and a second rigid rod connected in sequence;

[0014] The free end of the second rigid rod is provided with a buckle;

[0015] The first length measuring device comprises a fixing part and a measuring part installed on the fixing part, wherein the fixing part is arranged on the first rigid rod, and the measuring part passes through the ring buckle and is connected to one of the cable clamps;

[0016] The free end of the first rigid rod is connected to another cable clamp;

[0017] The second length measuring device has a higher measurement accuracy than the first length measuring device.

[0018] The data transmitter is connected to both the first length measuring device and the second length measuring device, and is used to obtain the lengths measured by the first length measuring device and the second length measuring device for calculating the cable force of the cable.

[0019] In this embodiment, preferably, there are multiple measuring components, and the multiple measuring components are distributed in a ring on the cable clamp.

[0020] Preferably, the elastic tensioning member comprises:

[0021] a constant force spring, one end of which is fixedly connected to the second length measuring device;

[0022] An adjusting nut has one end screwed onto the end of the constant force spring and the other end fixedly connected to the second rigid rod.

[0023] Preferably, the device further comprises:

[0024] A protective cover with telescopic capability is installed on the two cable hoops to enclose the measuring component in the protective cover.

[0025] Preferably, the first length measuring device is an electronic steel measuring tape; and / or the second length measuring device is an electronic micrometer.

[0026] Preferably, the cable hoop is provided with a hanging hole for hanging the measuring component.

[0027] Preferably, the spacing distance between the two cable clamps is 0.5-2 m.

[0028] In a second aspect, an embodiment of the present application further provides a method for measuring the tension of a cable, the method being based on the device for measuring the tension of a cable as described above, the method comprising the following steps:

[0029] Step 1: Install two cable hoops at intervals on the cable body in a stress-free state, and measure the initial distance X0 between the two cable hoops and the current initial ambient temperature T0;

[0030] Step 2: Hang the upper end of the cable body, and measure the first distance X1 between the two cable hoops and the cable body after hanging and the current first ambient temperature T1;

[0031] Step 3: Connect at least one measuring assembly between the two cable hoops, tension the elastic tensioning member, and obtain the correction length measured by the first length measuring device and the second length measuring device;

[0032] Step 4: Determine the current correction distance X1′ between the two cable hoops according to the sum of the correction lengths measured by the first length measuring device and the second length measuring device, and calculate the installation correction value △X1. The formula for calculating the installation correction value △X1 is:

[0033] △X1=X1′-X1-αX0(T1-T0),

[0034] Where α is the linear expansion coefficient of the material of the measuring part;

[0035] Step 5: tensioning the cable body, using a data transmitter to obtain the lengths to be measured measured by the first length measuring device and the second length measuring device, and determining the current distance to be measured Xi and the ambient temperature to be measured Ti between the two cable hoops;

[0036] Step 6: Calculate the cable force N on the tensioned cable according to the installation correction value △X1 and the distance and temperature measured before and after tensioning the cable. The formula for calculating the cable force N is:

[0037] N=EA[Xi-X0-△X1-αX0(Ti-T0)] / X0,

[0038] Wherein, E is the elastic modulus of the material of the cable, A is the cross-sectional area of ​​the cable, Xi is the distance to be measured, X0 is the initial distance, △X1 is the installation correction value, α is the linear expansion coefficient of the material of the measuring part, Ti is the ambient temperature to be measured, and T0 is the initial ambient temperature.

[0039] Preferably, after step 3 and before step 4, the method further comprises:

[0040] A protective cover with telescopic capability is installed on the two cable hoops to enclose the measuring component in the protective cover.

[0041] Preferably, in step 3, a plurality of measuring components are connected between the two cable hoops, and the plurality of measuring components are distributed in an annular manner on the cable hoops. After step 6, the method further comprises:

[0042] Step 7: Obtain multiple cable forces of the cable according to calculation, and take the average value of the multiple cable forces as the final cable force of the cable.

[0043] The beneficial effects of the technical solution provided by this application include:

[0044] The embodiment of the present application provides a device for measuring the tension of a cable, wherein the measuring part of a first length measuring device is passed through a ring at the end of a second rigid rod and connected to a cable clamp to measure the main distance, the deformation between the first rigid rod and the second rigid rod can be almost ignored, and a second length measuring device with a higher measurement accuracy than the first length measuring device is connected between the first rigid rod and the second rigid rod to assist the first length measuring device in further accurate measurement, and the second length measuring device is connected to an elastic tensioning member to ensure the accuracy of its measurement data; at the same time, the cable clamp is normally installed on the cable, and the length between the two cable clamps on the cable is accurately measured using the first length measuring device and the second length measuring device that are arranged in a coordinated manner, so that the length can be measured all day long, and the components of the device can be assembled after purchasing finished products, with low cost; importantly, in the present embodiment, the device is always installed on the cable when in use, and can obtain the deformation length data of the cable from the initial construction stage to the operation stage of the cable of the cable system bridge for calculating the cable tension, and its data traceability is good, providing important basic parameters for the maintenance of the cable system bridge, and effectively ensuring the reliable and safe performance of the cable system bridge.

[0045] The embodiment of the present application also provides a method for measuring the tension of a cable. Based on the above-mentioned device, the device is used to obtain the length between the two cable hoops on the cable multiple times and then the deformation length of the cable can be obtained. In the measurement method of the present embodiment, after the cable is hung, the length between the two cable hoops on the cable is corrected, and then a length measuring device is used to obtain the measured length of the cable, which can reduce the interference of ambient temperature on the obtained deformation length, that is, it is not affected by the environment; at the same time, the cable is not constrained by the physical properties of its length and stiffness; it can be seen that the cable tension calculated in the measurement of the embodiment of the present application is less affected by environmental factors, and the calculation is simple, so the cable tension can be accurately obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of a device for measuring cable force provided in an embodiment of the present application;

[0048] Figure 2 This is a schematic diagram of a cable clamp in an embodiment of the present application;

[0049] Figure 3 This is a schematic diagram of a second rigid rod provided with a buckle in an embodiment of the present application;

[0050] Figure 4 This is a schematic diagram of installing protective covers on two cable hoops in an embodiment of the present application;

[0051] Figure 5 This is a schematic diagram of initially installing two cable hoops on the cable at a distance of X0 in an embodiment of the present application;

[0052] Figure 6 This is a schematic diagram of the distance between two cable hoops X1′ after the cable is hooked in the embodiment of the present application;

[0053] Figure 7 A schematic diagram of a measuring assembly installed on a cable in an embodiment of the present application measuring a distance Xi to be measured between two cable hoops;

[0054] In the figure: 1. cable; 2. cable clamp; 21. hanging hole; 3. measuring assembly; 31. first length measuring device; 310. measuring part; 311. fixing part; 32. first rigid rod; 33. second length measuring device; 34. elastic tensioning member; 341. constant force spring; 342. adjusting nut; 35. second rigid rod; 351. buckle; 36. data transmitter; 4. protective cover. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0056] See also Figure 1 As shown, an embodiment of the present application provides a device for measuring the cable force, the device comprising:

[0057] Two cable hoops 2, the two cable hoops 2 are used to be arranged on the cable 1 at intervals;

[0058] At least one measuring assembly 3, the measuring assembly 3 comprising a data transmitter 36, a first length measuring device 31, and a first rigid rod 32, a second length measuring device 33, an elastic tensioning member 34, and a second rigid rod 35 connected in sequence;

[0059] The free end of the second rigid rod 35 is provided with a buckle 351, such as Figure 2 As shown;

[0060] The first length measuring device 31 includes a fixing portion 311 and a measuring portion 310 installed on the fixing portion 311. The fixing portion 311 is arranged on the first rigid rod 32. The measuring portion 310 passes through the ring buckle 351 and is connected to one of the cable clamps 2.

[0061] The free end of the first rigid rod 32 is connected to another cable clamp 2;

[0062] The measurement accuracy of the second length measuring device 33 is higher than that of the first length measuring device 31.

[0063] The data transmitter 36 is connected to both the first length measuring device 31 and the second length measuring device 33 , and is used to obtain the lengths measured by the first length measuring device 31 and the second length measuring device 33 , so as to calculate the cable force of the cable 1 .

[0064] The installation working principle of a device for measuring the cable force provided in an embodiment of the present application is as follows:

[0065] Two cable hoops 2 are installed on the cable 1 at an interval of one end, and then a measuring component 3 is installed between the two cable hoops 2. Specifically, a first rigid rod 32, a second length measuring device 33, an elastic tensioning member 34, and a second rigid rod 35 are connected in sequence in advance, and a first length measuring device 31 is installed on the first rigid rod 32, and the free end of the first rigid rod 32 is connected to one of the cable hoops 2, and the measuring part 310 wound in the first length measuring device 31 is stretched, and the measuring part 310 is passed through the buckle 351 at the free end of the second rigid rod 35 and then connected to the other cable hoop 2, and then a data transmitter is connected to the first length measuring device 31 and the second length measuring device 33. After the elastic tensioning member 34 is tensioned, the sum of the readings of the first length measuring device 31 and the second length measuring device 33 is the distance between the two cable hoops 2 on the cable 1. At this time, the device for measuring the cable force is installed, and then the cable force of the cable 1 is calculated based on the readings of the first length measuring device 31 and the second length measuring device 33.

[0066] In the embodiment of the present application, the measuring part 310 of the first length measuring device 31 is passed through the buckle 351 at the end of the second rigid rod 35 and connected to the rope clamp 2 to measure the main distance. The deformation between the first rigid rod 32 and the second rigid rod 35 can be almost ignored. The second length measuring device 33 with higher measurement accuracy than the first length measuring device 31 is connected between the first rigid rod 32 and the second rigid rod 35 to assist in further precise measurement of the accuracy range that the first length measuring device 31 cannot measure. The second length measuring device 33 is connected with an elastic tensioning member 34 to ensure that the measuring component 3 is tensioned to make the measured length data more accurate.

[0067] The device provided in the embodiment of the present application can be arranged on the cable 1 to measure the length around the clock, and the components of the device can be purchased as finished products and then assembled, which is relatively low in cost; when the device is in use, it is always installed on the cable 1, and can obtain the deformation length data of the cable from the cable 1 of the cable system bridge from the initial construction stage to the operation stage, so as to calculate the cable force of the cable, and its data has good traceability, which provides important basic parameters for the maintenance of the cable system bridge, and effectively ensures the reliable and safe performance of the cable system bridge.

[0068] Specifically, the spacing distance between the two cable hoops 2 is 0.5 to 2 m. In actual measurement, a multiple of 0.5 is appropriate.

[0069] Preferably, there are multiple measuring components 3, and the multiple measuring components 3 are distributed in an annular manner on the cable hoop 2. Figure 3 As shown, there are four measuring components 3, which are arranged in a circular array. Four length data are measured by using four measuring components 3 for subsequent cable force calculation and processing, thereby avoiding accidental errors caused by a single measurement and improving the accuracy of the calculation results of the embodiment of the present application.

[0070] See also Figure 4 As shown, specifically, the elastic tensioning member 34 includes a constant force spring 341 and an adjusting nut 342, one end of the constant force spring 341 is fixedly connected to the second length measuring device 33; one end of the adjusting nut 342 is screwed on the end of the constant force spring 341, and the other end is fixedly connected to the second rigid rod 35. In this embodiment, the adjusting nut 342 is used to rotate on the end of the constant force spring 341 to shorten the length of the constant force spring 341 and thus achieve tensioning.

[0071] Furthermore, the device further comprises a protective cover 4 with telescopic capability, which is mounted on the two cable hoops 2 to enclose the measuring assembly 3 in the protective cover 4. The protective cover 4 with telescopic capability is mounted on the two cable hoops 2 and can adapt to the deformation of the cable 1. In this embodiment, the two ends of the protective cover 4 may be a shell made of rigid material, and a telescopic section such as a bellows may be used in the middle; or the protective cover 4 may be directly made of a material with elastic telescopic capability. It is preferred that the telescopic capability of the protective cover 4 is -0.5 to 5 m.

[0072] Furthermore, the data transmitter 36 can be installed on the protective cover 4, and preferably a protective cover made of a rigid material and a retractable material is used. The data transmitter 36 is installed on the rigid material, which is easy to install and ensures the safety of the data transmitter 36 in the protective cover 4. After the data transmitter 36 obtains the length measured by the first length measuring device 31 and the second length measuring device 33, it sends it to the remote terminal for later calculation of the cable force using the measured length.

[0073] Preferably, the first length measuring device 31 is an electronic steel tape measure; and / or the second length measuring device 33 is an electronic micrometer. In this embodiment, the fixing portion 311 is the shell of the electronic steel tape measure, and the measuring portion 310 is a steel tape measure rolled in the shell. Generally speaking, the measurement accuracy of the electronic steel tape measure is to the millimeter, and the measurement accuracy of the electronic micrometer is accurate to 0.001mm. The two cooperate with each other to accurately measure the distance between the two cable hoops 2 for later data processing, and then obtain the accurate cable force value of the cable 1. The measurement range of the electronic steel tape measure is 0 to 5m, and the electronic digital display function of the electronic micrometer can also read directly, which can be read before connecting the data transmitter, or directly before installing the protective cover 4.

[0074] Specifically, the cable clamp 2 is provided with a hanging hole 21 for hanging the measuring assembly 3. The hanging hole 21 facilitates quick connection of a hanging ear matched with the hanging hole 21 during installation and connection, and it is also simple and easy to operate to arrange the hanging ear at the position where the first length measuring device 31 and the first rigid rod 32 are connected to the cable clamp 2.

[0075] The embodiment of the present application further provides a method for measuring the tension of a cable, the method is based on the device for measuring the tension of a cable as described above, and the method comprises the following steps:

[0076] Step 1: Install two cable hoops 2 at intervals on the cable 1 in a stress-free state, and measure the initial distance X0 between the two cable hoops 2 and the current initial ambient temperature T0, see Figure 5 As shown;

[0077] Step 2: Hang the upper end of the cable 1, and measure the first distance X1 between the two cable hoops 2 and the cable 1 after hanging and the current first ambient temperature T1;

[0078] Step 3: Connect at least one measuring assembly 3 between the two cable hoops 2, tension the elastic tensioning member 34, and obtain the correction length measured by the first length measuring device 31 and the second length measuring device 33;

[0079] Step 4: Determine the current correction distance X1′ between the two cable hoops 2 according to the sum of the correction lengths measured by the first length measuring device 31 and the second length measuring device 33, see Figure 6 As shown, the installation correction value △X1 is calculated, and the formula for calculating the installation correction value △X1 is:

[0080] △X1=X1′-X1-αX0(T1-T0),

[0081] Wherein, α is the linear expansion coefficient of the material of the measuring portion 310;

[0082] Step 5: tension the cable 1, use the data transmitter 36 to obtain the lengths to be measured measured by the first length measuring device 31 and the second length measuring device 33, and determine the current distance Xi to be measured and the ambient temperature Ti to be measured between the two cable hoops 2, see Figure 7 As shown;

[0083] Step 6: Calculate the cable force N of the tensioned cable 1 according to the installation correction value △X1 and the distance and temperature measured before and after tensioning the cable 1. The formula for calculating the cable force N is:

[0084] N=EA[Xi-X0-△X1-αX0(Ti-T0)] / X0,

[0085] In the formula, E is the elastic modulus of the material of the cable 1, A is the cross-sectional area of ​​the cable 1, Xi is the distance to be measured, X0 is the initial distance, △X1 is the installation correction value, α is the linear expansion coefficient of the material of the measuring part 310, Ti is the ambient temperature to be measured, and T0 is the initial ambient temperature.

[0086] A method for measuring the tension of a cable provided in an embodiment of the present application is based on the above-mentioned device. The device is used to obtain the length between the two cable hoops on the cable multiple times and then the deformation length of the cable can be obtained. In the measurement method of the present embodiment, after the cable is hung, the length between the two cable hoops on the cable is corrected, and then a length measuring device is used to obtain the measured length of the cable, which can reduce the interference of ambient temperature on the obtained deformation length, that is, it is not affected by the environment; at the same time, the cable is not constrained by the physical properties of its length and stiffness; it can be seen that the cable tension calculated in the measurement of the embodiment of the present application is less affected by environmental factors, and the calculation is simple, so the cable tension can be accurately obtained.

[0087] Preferably, after step 3 and before step 4, the method further comprises:

[0088] A protective cover 4 with telescopic capability is installed on the two cable clamps 2 to enclose the measuring component 3 in the protective cover 4 .

[0089] In this embodiment, the device is always installed on the cable 1. In order to ensure the measurement accuracy of the device for a long time, it is necessary to eliminate the interference of the environment on the measuring component 3 as much as possible. Therefore, a protective cover 4 capable of enclosing the measuring component 3 is installed on the two cable clamps 2, and the protective cover 4 can also adapt to the deformation of the cable body of the cable 1.

[0090] Preferably, in step 3, a plurality of measuring components 3 are connected between the two cable hoops 2, and the plurality of measuring components are distributed in an annular manner on the cable hoops 2. After step 6, the method further comprises:

[0091] Step 7: Obtain multiple cable forces of the cable 1 according to calculation, and take the average value of the multiple cable forces as the final cable force of the cable.

[0092] In this embodiment, four measuring components 3 are connected between the two cable clamps 2. After the corresponding cable forces are calculated respectively, the average value of the obtained cable forces is calculated, or the cable forces are averaged after removing the data with obvious measurement errors, so as to avoid accidental errors caused by single measurements and improve the accuracy of the calculation results of the embodiments of the present application.

[0093] Meanwhile, in the embodiment of the present application, the two cable hoops 2 are both installed on the straight section of the cable 1 .

[0094] Specifically, the data transmitter 36 in the measuring component 3 can be installed together with other components in the measuring component 3, or the data transmitter 36 can be installed when the protective cover 4 is installed, wherein the data transmitter 36 can be electrically connected to the first length measuring device 31 and the second length measuring device 33, or can be wirelessly connected.

[0095] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0096] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0097] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A device for measuring the tension of a cable, characterized in that: The device comprises: Two cable hoops (2), the two cable hoops (2) being arranged on the cable (1) at intervals; At least one measuring assembly (3), the measuring assembly (3) comprising a data transmitter (36), a first length measuring device (31), and a first rigid rod (32), a second length measuring device (33), an elastic tensioning member (34), and a second rigid rod (35) connected in sequence; The free end of the second rigid rod (35) is provided with a ring buckle (351); The first length measuring device (31) comprises a fixing portion (311) and a measuring portion (310) mounted on the fixing portion (311), wherein the fixing portion (311) is arranged on the first rigid rod (32), and the measuring portion (310) passes through the ring buckle (351) and is connected to a cable hoop (2); The free end of the first rigid rod (32) is connected to another cable clamp (2); The second length measuring device (33) has a higher measurement accuracy than the first length measuring device (31) The data transmitter (36) is connected to the first length measuring device (31) and the second length measuring device (33) and is used to obtain the lengths measured by the first length measuring device (31) and the second length measuring device (33) so as to calculate the cable force of the cable (1); The number of the measuring components (3) is multiple, and the multiple measuring components (3) are distributed in a ring shape on the cable clamp (2); The elastic tensioning member (34) comprises: A constant force spring (341), one end of which is fixedly connected to the second length measuring device (33); An adjusting nut (342) has one end screwed onto the end of the constant force spring (341) and the other end fixedly connected to the second rigid rod (35).

2. The device for measuring cable force according to claim 1, characterized in that: The device also includes: A protective cover (4) with telescopic capability is installed on the two cable hoops (2) to enclose the measuring component (3) in the protective cover (4).

3. The device for measuring cable force according to claim 1, characterized in that: The first length measuring device (31) is an electronic steel measuring tape; and / or the second length measuring device (33) is an electronic micrometer.

4. The device for measuring cable force according to claim 1, characterized in that: The cable hoop (2) is provided with a hanging hole (21) for hanging the measuring component (3).

5. The device for measuring cable force according to claim 1, characterized in that: The distance between the two cable hoops (2) is 0.5 to 2 m.

6. A method for measuring cable tension, the method being based on the device for measuring cable tension as claimed in any one of claims 1 to 5, characterized in that: The method comprises the following steps: Step 1: Install two cable hoops (2) at intervals on the cable (1) in a stress-free state, and measure the initial distance X0 between the two cable hoops (2) and the current initial ambient temperature T0; Step 2: Hang the upper end of the cable (1), and measure the first distance X1 between the two cable clamps (2) and the cable (1) after hanging and the current first ambient temperature T1; Step 3: Connect at least one measuring assembly (3) between the two cable hoops (2), tension the elastic tensioning member (34), and obtain the correction length measured by the first length measuring device (31) and the second length measuring device (33); Step 4: Determine the current correction distance X1′ between the two cable hoops (2) based on the sum of the correction lengths measured by the first length measuring device (31) and the second length measuring device (33), and calculate the installation correction value △X1. The formula for calculating the installation correction value △X1 is: △X1=X1′-X1-αX0(T1-T0), Wherein, α is the linear expansion coefficient of the material of the measuring portion (310); Step 5: tensioning the cable (1), using a data transmitter (36) to obtain the lengths to be measured measured by the first length measuring device (31) and the second length measuring device (33), and determining the current distance to be measured Xi and the ambient temperature to be measured Ti between the two cable hoops (2); Step 6: Calculate the cable force N on the tensioned cable (1) based on the installation correction value △X1 and the distance and temperature measured before and after tensioning the cable (1). The formula for calculating the cable force N is: N=EA[Xi-X0-△X1-αX0(Ti-T0)] / X0, In the formula, E is the elastic modulus of the material of the cable (1), A is the cross-sectional area of ​​the cable (1), Xi is the distance to be measured, X0 is the initial distance, △X1 is the installation correction value, α is the linear expansion coefficient of the material of the measuring part (310), Ti is the ambient temperature to be measured, and T0 is the initial ambient temperature.

7. The method for measuring cable force according to claim 6, characterized in that: After step 3 and before step 4, the method further includes: A protective cover (4) with telescopic capability is installed on the two cable hoops (2) to enclose the measuring component (3) in the protective cover (4).

8. The method for measuring cable force according to claim 6, characterized in that: In step 3, a plurality of measuring components (3) are connected between the two cable clamps (2), and the plurality of measuring components are distributed in an annular manner on the cable clamp (2). After step 6, the method further comprises: Step 7: Obtain multiple cable forces of the cable (1) according to calculation, and take the average value of the multiple cable forces as the final cable force of the cable.

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