Cable force measuring device

Abstract

The present invention discloses a cable force measuring device, comprising a fixing mechanism and a vibrating-wire strain gauge, the fixing mechanism comprising a strap, a locking piece and a slide, the strap being fixed to a preset position of the cable by the locking piece, the slide being arranged on the strap in a manner that it can slide circumferentially around the cable; the fixing mechanism comprises at least two groups axially arranged on the cable, the vibrating-wire strain gauge being arranged between the two groups of the fixing mechanisms, and the axial ends of the vibrating-wire strain gauge being respectively fixed on the corresponding slides in the two groups of the fixing mechanisms; the device can meet the requirements of convenient assembly and fixation of the vibrating-wire strain gauge, and can avoid damaging the cable, thereby meeting the requirements of accurate measurement of the cable force of a cable with a hinged structure.

Description

Technical Field

[0001] The present invention relates to the field of cable structure health monitoring, and in particular to a cable force measuring device suitable for a cable with a hinged structure. Background Art

[0002] As one of the most important components of building structures, monitoring and clarifying the cable force values ​​at different stress stages is of great significance to ensuring structural performance and safety.

[0003] Common cable tension monitoring methods include pressure gauge, magnetic flux, vibration, and fixture methods. The pressure gauge method is not suitable for long-term cable tension monitoring, while the magnetic flux and vibration methods are complex and require multiple steps. The fixture method measures the strain between cable segments and calculates the cable tension, making it simpler to operate. The vibrating wire strain measurement method is a structural strain measurement method based on the relationship between the vibration frequency and tension of the tensioning wire. This measurement method offers advantages such as simple structure, easy installation, strong anti-interference capabilities, and low signal distortion, making it suitable for long-term cable tension monitoring. However, practical applications show that the use of vibrating wire strain gauges for cable tension measurement still has the following limitations.

[0004] First, traditional vibrating-wire strain gauges, consisting of a vibrating-wire strain gauge, a mounting bracket, and a signal transmission cable, are often limited in their responsiveness by the shape of the structure being measured. To avoid damaging the mechanical properties of cables when measuring strain, the vibrating-wire strain gauge cannot be directly welded to the cable segment. Furthermore, because cables are smooth and often arc-shaped, gluing the gauge to the spiral wire segment is not feasible. Using a clamp for fixing would require different clamps for cables of different diameters, making operation more inconvenient.

[0005] The second limitation is also the biggest one. Common cables can be divided into steel wire ropes, steel strands, steel wire bundles, steel rods, etc. When using vibrating wire strain gauges to measure the cable force of simple cables, such as parallel steel wire bundles and steel rods, the vibrating wire strain gauge can be installed on the cable through a fixing device. However, for cables with a hinged structure composed of multiple steel wires, such as steel strands and semi-parallel steel wire bundles, if the vibrating wire strain gauge is directly fixed on the cable, due to the change in the force on the cable, different cross-sections will rotate relative to each other. Similarly, the two ends of the vibrating wire strain gauge will also undergo relative torsion. However, the vibrating wire strain gauge must be maintained on the same horizontal line during measurement. Once relative rotation occurs, it will lead to increased measurement errors or even measurement failure.

[0006] Therefore, in response to the above technical problems, a cable force measurement device with variable diameter and circumferential sliding is proposed. It is used in the field of cable force monitoring. It can not only meet the needs of convenient assembly and fixation of vibrating wire strain gauges, but also accurately obtain the actual strain value of the cable. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to overcome the defects in the prior art and provide a cable force measuring device that can not only meet the needs of convenient assembly and fixation of vibrating wire strain gauges, but also overcome the limitations of large measurement errors caused by the hinged structure of the cable, and avoid damage to the cable. Under the premise of avoiding the damage to the cable, it can meet the requirements of accurate measurement of the cable force with a hinged structure and accurately obtain the actual cable force value of the cable.

[0008] The cable tension measuring device of the present invention includes a fixing mechanism and a vibrating-wire strain gauge, wherein the fixing mechanism includes a strap, a locking member and a slide, wherein the strap is fixed to a preset position of the cable by the locking member, and the slide is arranged on the strap in a manner that it can slide circumferentially around the cable; the fixing mechanism includes at least two groups axially arranged on the cable, and the vibrating-wire strain gauge is arranged between the two groups of the fixing mechanisms, and the axial ends of the vibrating-wire strain gauge are respectively fixed to the corresponding slides in the two groups of the fixing mechanisms.

[0009] Furthermore, the strap has fixed teeth, and the fixing mechanism also includes a driving gear disc, which has driving teeth arranged radially along the driving gear disc. The driving teeth are adapted to the fixed teeth for meshing transmission, and the locking member is used to cooperate with the fixed teeth to fix the strap at a preset position of the cable.

[0010] Furthermore, the slide is mounted on the strap via a fixed seat, the fixed seat is fixed to the strap, and the slide is limited on the fixed seat; the slide is slidably arranged on the fixed seat, and the fixed seat and the fixed teeth are located on the same side of the strap.

[0011] Furthermore, the sliding seat is arranged on the fixing seat through a ball bearing, and the fixing seat has a limiting portion for limiting the sliding seat.

[0012] Furthermore, there are at least two groups of balls, and the two groups of balls are respectively arranged on the front side and the rear side of the slide seat along the axial direction of the cable.

[0013] Furthermore, a limiting support is fixed on the slide for limiting and fixing one axial end of the vibrating wire strain gauge.

[0014] Furthermore, a functional hole is provided on the fixing seat, and the functional hole is opened along the binding direction of the strap.

[0015] Furthermore, a support baffle is fixed on the strap, and the driving gear disc is installed on the support baffle in a manner that can be driven to rotate; a driving shaft that can be driven to rotate is provided on the support baffle, and the driving gear disc is fixed to the driving shaft in a sleeve manner, and the axis of the driving gear disc and the axis of the driving shaft are coaxially arranged.

[0016] Furthermore, the driving gear disc is located on the top of the fixed tooth, and the locking member is hinged to the supporting baffle through a connecting pin, and the central axis of the connecting pin is parallel to the central axis of the driving shaft.

[0017] The beneficial effects of the present invention are as follows: a cable force measuring device disclosed in the present invention comprises a fixing mechanism and a vibrating-wire strain gauge, the fixing mechanism comprising a strap, a locking piece and a slide, the strap being fixed to a preset position of the cable by the locking piece, the slide being arranged on the strap in a manner that it can slide circumferentially around the cable; the fixing mechanism comprises at least two groups axially arranged on the cable, the vibrating-wire strain gauge is arranged between the two groups of the fixing mechanisms, and the axial ends of the vibrating-wire strain gauge are respectively fixed on the corresponding slides in the two groups of the fixing mechanisms; it overcomes the limitations of the prior art in measuring the force of cables with a hinged structure, can meet the convenient assembly and fixation of the vibrating-wire strain gauge, and can overcome the limitation of large measurement errors caused by the hinged structure of the cable, and can avoid the cable from being damaged, meet the accurate measurement of the force of cables with a hinged structure, accurately obtain the actual strain value of the cable, and improve the accuracy and reliability of the vibrating-wire strain gauge in measuring cable strain data and the sustainability of the use of the fixing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0019] Figure 1 It is a side structural schematic diagram of the present invention;

[0020] Figure 2 It is a schematic diagram of the top view of the structure of the present invention;

[0021] Figure 3 This is a structural schematic diagram of the present invention applied to a cable;

[0022] Figure 4 This is a schematic diagram of the cross-sectional structure of the present invention applied to a cable;

[0023] Figure 5 This is a structural diagram of the connection between the sliding seat and the fixed seat of the present invention;

[0024] Figure 6 This is a schematic diagram of the axial structure of the present invention applied to a cable. DETAILED DESCRIPTION

[0025] Figure 1This is a structural diagram of the present invention. As shown in the figure, the circumferential direction is the axial direction around the cable 001, which will not be repeated here. The cable force measuring device in this embodiment includes a fixing mechanism and a vibrating wire strain gauge 01, and the fixing mechanism includes a strap 02, a locking member 03 and a slide 04. The strap 02 is fixed to a preset position of the cable 001 by the locking member 03, and the slide 04 is arranged on the strap 02 in a manner that it can slide circumferentially around the cable 001; the fixing mechanism includes at least two groups axially arranged on the cable 001, and the vibrating wire strain gauge 01 is arranged between the two groups of the fixing mechanisms, and the axial ends of the vibrating wire strain gauge 01 are respectively fixed on the corresponding slides 04 in the two groups of the fixing mechanisms.As shown in the figure, the cooperation of the strap 02 and the locking member 03 in this solution realizes the axial fixation of the slide 04 at the preset position of the cable 001, and the structural design of the strap 02 can also be applied to cables 001 of different diameters, with a wider range of applications, and can ensure the stability and effectiveness of the positioning of the slide 04, and ensure the reliability of the slide 04 when in use. In fact, the fixing mechanism can also be in the form of a clip or a buckle to position the slide 04 at the preset position of the cable 001, which will not be repeated here; the use of two sets of fixing mechanisms makes the vibrating wire strain gauge 01 more accurate in measurement, and the fixed mechanism in this solution There are two sets of fixing mechanisms. In fact, the two sets of fixing mechanisms can also be fixed at two positions of the cable 001 in a deflectable manner. Since the cable 001 with a twisted structure will have a relative rotation angle at different sections after being stressed, if the two ends of the vibrating wire strain gauge 01 are directly fixed on the two sections, the vibrating wire strain gauge 01 will be twisted after being stressed and cannot be measured. The use of two independent mechanisms allows the cable 001 to transmit the torsional force through the slide 04 that can slide around the cable 001 when it deflects, avoiding the twisting of the vibrating wire strain gauge 01, which can overcome the problem caused by the twisted structure of the cable 001. The limitation of large measurement error is eliminated. Under the premise of avoiding the damage of the cable 001, the accurate measurement of the cable force of the cable 001 with a hinged structure is met, and the actual cable force value of the cable 001 is accurately obtained. That is, the strap 02 and the locking piece 03 of each set of fixing mechanisms can be regarded as a whole with the preset positioning point corresponding to the cable 001, and the axial ends of the vibrating wire strain gauge 01 are respectively fixed on the corresponding slides 04 in the two sets of the fixing mechanisms, so that the vibrating wire strain gauge 01 can be regarded as directly measuring the cable force of the cable 001, thereby improving the measurement accuracy of the vibrating wire strain gauge 01; at the same time, the strap 0 2 and the quick-disassembly and quick-assembly method of the locking part 03 is applied in the field of cable force monitoring, and can also meet the convenient assembly and fixation of the vibrating wire strain gauge 01, and the fixation stability is improved. During the tensioning process of the cable 001, the cable 001 will produce axial strain, that is, strain in the length direction of the cable 001. After the specific value of the strain is measured by the vibrating wire strain gauge 01, the specific cable force value of the cable 001 can be obtained by calculation through the material properties of the cable 001. The vibrating wire strain gauge 01 can be installed on the corresponding slide 04 using any one of the existing technologies, which will not be repeated here.

[0026] In this embodiment, the strap 02 has fixed teeth 05, and the fixed teeth 05 are arranged in the extension direction of the strap 02. The fixing mechanism also includes a driving gear disc 06, and the driving gear disc 06 has driving teeth 07 arranged along the radial direction of the driving gear disc 06. The driving teeth 07 are adapted to the fixed teeth 05 for meshing transmission, and the locking member 03 is used to cooperate with the fixed teeth 05 to fix the strap 02 at the preset position of the cable 001. As shown in the figure, a support baffle 08 is fixed on the strap 02, and the driving gear disc 06 is installed on the support baffle 08 in a manner that can be driven to rotate; a driving shaft 09 that can be driven to rotate is provided on the support baffle 08, and one axial end of the driving shaft 09 is connected to a driving handle 10, and the driving shaft 09 is driven to rotate by the driving handle 10, and the driving gear disc 06 is fixed to the driving shaft 09 in a sleeve manner, and the axis of the driving gear disc 06 and the axis of the driving shaft 09 are coaxially arranged, and the support baffle 08 is two pieces arranged in opposite directions in the transverse direction to improve the stability of supporting the driving gear disc 06, the support baffle 08 is arranged near the head end of the extension direction of the strap 02, and the fixed tooth 05 is arranged near the end of the extension direction of the strap 02. When in use, the strap 02 passes around the cable to be measured 001 in the circumferential direction and passes through the two support baffles 08, so that the driving tooth 07 and the fixed tooth 05 are engaged, and the driving is continuously rotated. The movable gear disc 06 can lock the strap 02 to the preset position of the cable 001; the driving gear disc 06 is located at the top of the fixed tooth 05, and the locking member 03 is hinged to the support baffle 08 through a connecting pin, and the central axis of the connecting pin is parallel to the central axis of the driving shaft 09; when the fixed tooth 05 and the driving tooth 07 are engaged to lock the strap 02 to the preset position of the cable 001, the locking member 03 is moved to cooperate with the fixed tooth 05, forcing the fixed tooth 05 and the driving tooth 07 not to reverse. At this time, the strap 02 can be continuously fixed at the preset position of the cable 001. As shown in the figure, the locking member 03 in this scheme is moved upward when used so that the locking member 03 does not interfere with the engagement of the fixed tooth 05 and the driving tooth 07. When the strap 02 needs to be positioned, the locking member 03 is moved downward so that the locking member 03 and the fixed tooth 05 are locked together to prevent the strap 02 from escaping from the cable 001 and improve the stability of the fixation of the strap 02.

[0027] In this embodiment, the slide 04 is installed on the strap 02 through the fixed seat 11, and the fixed seat 11 is fixed on the strap 02. The slide 04 is limited on the fixed seat 11, and the slide 04 is located at the top in the height direction of the fixed seat 11. The fixed seat 11 is provided with a functional hole 12, and the functional hole 12 is opened along the bundling direction of the strap 02. The functional hole 12 is located at the bottom in the height direction of the slide 04, and the fixed seat 11 is adjacent to the support baffle 08 and is arranged close to the head end in the extension direction of the strap 02, and the support baffle 08 is closer to the head end in the extension direction of the strap 02, so that after the strap 02 is passed through the support baffle 08, it is necessary to pass through the functional hole 12 on the fixed seat 11, thereby improving the restriction effect on the strap 02 and further preventing the strap 02 from retreating; the slide 04 is slidably set on the fixed seat 11, and the fixed seat 11 and the fixed tooth 05 are located on the same side of the strap 02. As shown in the figure, the slide 04 is set on the fixed seat 11 through the ball 13. The fixed seat 11 has a limiting portion 14 for limiting the slide 04, so that the slide 04 will not deviate from the range limited by the fixed seat 11; the ball 13 is at least two groups, and the two groups of balls 13 are respectively arranged on the front side of the slide 04 and the rear side of the slide 04 along the axial direction of the cable 001; the front and back are the front and back in the width direction of the strap 02, which will not be repeated here, further reducing friction, and improving the sliding stability and follow-up performance of the slide 04, and the vibration can be released in time when the cable 001 undergoes radial deflection. The circumferential displacement constraint of the string strain gauge 01 improves the measurement accuracy of the vibrating wire strain gauge 01; a limit support 15 is fixed on the slide 04 for limiting and fixing one axial end of the vibrating wire strain gauge 01; as shown in the figure, in this solution, the limit support 15 is fixed to the top of the slide 04, and the two ends of the vibrating wire strain gauge 01 are respectively fixed to the limit supports 15 in the two sets of fixing mechanisms, completing the fixed installation of the entire device. The installation of the vibrating wire strain gauge 01 and the limit support 15 is detachable, which is convenient for subsequent disassembly, easy to carry, and has the characteristics of reusability.

[0028] This solution also discloses a method for using a cable force measuring device. The steps are as follows:

[0029] S1. The vibrating wire strain gauge 01 is mounted on the two sets of fixing mechanisms corresponding to the respective slides 04;

[0030] S2. The two sets of fixing mechanisms in each corresponding strap 02 are fixed to the preset position of the cable 001;

[0031] S3. Adjust the horizontal angle of the vibrating wire strain gauge 01 so that both ends of the axial direction of the vibrating wire strain gauge 01 are on the same horizontal line and no relative torsion occurs;

[0032] S4. Before cable 001 is subjected to force, record the initial reference frequency value f0 of vibrating wire strain gauge 01. After cable 001 is subjected to force, monitor the cable force.

[0033] S5. At a certain time i during the monitoring process, observe whether the axial ends of the vibrating wire strain gauge 01 are still on the same horizontal line;

[0034] If so, record the frequency value f at time i i 、T i If not, adjust the slide 04 so that the two ends of the axial direction of the vibrating wire strain gauge 01 are on the same horizontal line and record the frequency value f at time i i 、T i ;

[0035] S6. Data processing: By substituting the material properties of cable 001, the actual cable force F of cable 001 can be obtained. The specific calculation formula is as follows:

[0036]

[0037] F=εEA

[0038] Where: ε—strain generated by vibrating wire strain gauge 01, no unit;

[0039] K—The linear relationship coefficient between the frequency value and strain output by the vibrating wire strain gauge 01, also known as the sensitivity coefficient of the vibrating wire strain gauge 01, which has been calibrated at the factory. Unit: 1 / Hz 2 ;

[0040] f i —Frequency value of vibrating wire strain gauge O1 at time i, Hz;

[0041] f0—reference frequency value of vibrating wire strain gauge 01 in the initial state, Hz;

[0042] K t —The relationship coefficient between strain and temperature of vibrating wire strain gauge 01 is calibrated at the factory, unit: 1 / ℃;

[0043] T i —Temperature during detection, i.e., the temperature during measurement, °C;

[0044] t0—The temperature during factory inspection and calibration, that is, the temperature during measurement, ℃.

[0045] F—actual cable force value of cable 001, N;

[0046] E—elastic modulus of cable 001 material, MPa;

[0047] A—Cable 001 cross-sectional area, mm 2 ;

[0048] S7. After the monitoring is completed, the two sets of fixing mechanisms fixed on the cable 001 are removed.

[0049] This device is installed for measurement before the cable 001 is tensioned or subjected to force. During the monitoring process, the entire device is always installed on the cable 001 until the monitoring is completed; it can ensure the stability and data accuracy of the vibrating wire strain gauge 01 during long-term monitoring, and provide reliable data support and basis for structural health and safety; the patent of this invention introduces the surface vibrating wire strain gauge 01 into the cable force measurement of the cable 001 with a hinged structure, and can continuously and long-term monitor the cable force of the cable 001; it is easy to operate, the results are accurate, and the cost-effectiveness is high; it provides reliable data support and basis for the detection of the effective prestress of the cable 001 during the tensioning and use stages of the steel structure using the prestressed cable 001 and the safety assessment of the structure.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A cable force measuring device, characterized in that: It includes a fixing mechanism and a vibrating-wire strain gauge, the fixing mechanism includes a strap, a locking piece and a slide, the strap is fixed to the preset position of the cable by the locking piece, and the slide is arranged on the strap in a manner that it can slide circumferentially around the cable; the fixing mechanism includes at least two groups axially arranged on the cable, the vibrating-wire strain gauge is arranged between the two groups of the fixing mechanisms, and the axial ends of the vibrating-wire strain gauge are respectively fixed to the corresponding slides in the two groups of the fixing mechanisms; the strap has fixed teeth, and the fixing mechanism also includes a driving gear disc, the driving gear disc has driving teeth arranged radially along the driving gear disc, and the driving teeth are meshed with the fixed teeth, and the locking piece is used to cooperate with the fixed teeth to fix the strap to the preset position of the cable.

2. The cable force measuring device according to claim 1, characterized in that: The slide is mounted on the strap via a fixed seat, the fixed seat is fixed on the strap, and the slide is limited on the fixed seat; the slide is slidably arranged on the fixed seat, and the fixed seat and the fixed teeth are located on the same side of the strap.

3. The cable force measuring device according to claim 2, characterized in that: The sliding seat is arranged on the fixing seat through a ball bearing, and the fixing seat has a limiting portion for limiting the sliding seat.

4. The cable force measuring device according to claim 3, characterized in that: There are at least two groups of balls, and the two groups of balls are respectively arranged on the front side and the rear side of the slide seat along the axial direction of the cable.

5. The cable force measuring device according to claim 2, characterized in that: A limiting support for limiting and fixing one axial end of the vibrating wire strain gauge is fixed on the sliding seat.

6. The cable force measuring device according to claim 2, characterized in that: The fixing seat is provided with a functional hole, and the functional hole is opened along the binding direction of the strap.

7. The cable force measuring device according to claim 1, characterized in that: A supporting baffle is fixed on the strap, and the driving gear disc is installed on the supporting baffle in a manner that can be driven to rotate; a driving shaft that can be driven to rotate is provided on the supporting baffle, and the driving gear disc is fixed to the driving shaft in a sleeve manner, and the axis of the driving gear disc and the axis of the driving shaft are coaxially arranged.

8. The cable force measuring device according to claim 7, characterized in that: The driving gear disc is located on the top of the fixed tooth, and the locking member is hinged to the supporting baffle through a connecting pin shaft, and the central axis of the connecting pin shaft is parallel to the central axis of the driving shaft.

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