A fiber optic sensor calibration fixture

Abstract

This utility model relates to the field of calibration equipment technology, and provides a calibration fixture for a fiber optic sensor. It includes a mounting beam with a first limiting groove for placing the fiber optic sensor. The first limiting groove has a through slot providing space for axial deformation of the mounting beam. Hoops are movably fitted onto both ends of the mounting beam at the axial direction of the fiber optic sensor. Pressure plates are slidably connected within the hoops, and locking bolts are threaded onto the hoops to abut against the pressure plates and securely fix the fiber optic sensor within the first limiting groove. This fixture achieves fiber optic sensor positioning, free deformation transmission of the mounting beam, adaptation to fiber optic sensors of different lengths, and stable fixation. It effectively avoids calibration errors caused by fiber optic sensor misalignment, limited deformation of the mounting beam, and insecure fixation, improving calibration accuracy and fixture compatibility.

Description

Technical Field

[0001] This utility model relates to the field of calibration equipment technology, and more specifically, to a fiber optic sensor calibration fixture. Background Technology

[0002] Fiber optic sensors can convert the state of the measured object into a measurable optical signal. With advantages such as resistance to electromagnetic interference, corrosion resistance, and high measurement accuracy, they are widely used in strain, displacement, and temperature detection. Their working principle involves the light source being fed into a modulator via an optical fiber. The measured parameter alters the wavelength, phase, and other optical properties of the light, forming a modulated signal light to complete the measurement. Pre-stretching assembly is a common method in their fabrication. For example, the fiber optic strain sensor disclosed in existing technologies (patents CN219284226U and CN222689111U) uses a structure where one end of a fiber optic grating is welded to a prismatic substrate and the other end to a slider, and the slider is pre-stretched before being welded to the prismatic substrate.

[0003] To ensure the measurement accuracy of this type of sensor in practical applications, its sensitivity coefficient, linearity, and other parameters must be calibrated using a dedicated device before leaving the factory. For example, in patent CN215413626U, the strain gauge is fixed in a V-groove of an outer clamp and an inner clamp, and the distance is adjusted to eliminate axial force on the strain gauge. A dial indicator is used to contact the inner clamp, and then the hand crank is rotated to pull / push the inner clamp, causing the strain gauge and dial indicator to undergo synchronous tensile / compressive deformation. This cycle is repeated to obtain the calibration results for the strain gauge's sensitivity, linearity, etc. In this process, the installation and fixing state of the sensor during calibration directly determines the reliability of the calibration data.

[0004] Currently, most calibration fixtures for fiber optic sensors are dedicated structures designed for specific sensor specifications. These fixtures have poor adaptability; calibrating different sensor specifications requires replacing the entire fixture, increasing costs and reducing efficiency. Furthermore, their fixing reliability and positioning accuracy are insufficient. Some fixtures only use simple bolt tightening to fix the sensor, which can easily lead to axial slippage or radial offset during calibration. This results in a discrepancy between the displacement measured by the dial indicator and the actual displacement generated by the sensor under force, introducing calibration errors. Utility Model Content

[0005] The purpose of this invention is to provide a calibration fixture for fiber optic sensors, which solves the problems of poor adaptability and insufficient positioning accuracy of existing fiber optic sensor calibration fixtures.

[0006] This utility model is achieved through the following technical solution: a fiber optic sensor calibration fixture, including a mounting beam, the mounting beam having a first limiting groove for placing the fiber optic sensor, the first limiting groove having a through slot to provide space for axial deformation of the mounting beam, and hoops being movably sleeved on the mounting beam at both ends of the fiber optic sensor, with pressure plates slidably connected inside the hoops, and locking bolts threaded onto the hoops for abutting against the pressure plates to press and fix the fiber optic sensor in the first limiting groove.

[0007] Furthermore, a second limiting groove is provided on the side wall of the installation beam, and the hoop is slidably connected in the second limiting groove. The inner walls at both ends of the second limiting groove restrict the hoop from moving away from each other.

[0008] Furthermore, a slot is provided axially in the second limiting groove, and the hoop is threadedly connected with an adjusting bolt that abuts against the slot to lock the relative position of the hoop and the mounting beam.

[0009] Furthermore, a limiting hole is provided in the second limiting groove, and the limiting hole is connected to a washer for limiting the close proximity of the hoops by a screw with a threaded connection.

[0010] Furthermore, the bottom of the pressure plate is provided with positioning protrusions that abut against the inner walls of both sides perpendicular to the axial direction of the first limiting groove.

[0011] Furthermore, the pressure plate has a slot for engaging with the fiber optic sensor.

[0012] Furthermore, the hoop includes a bolted gantry and a base plate, and the gantry is equipped with a slide rail that slides and engages with the pressure plate.

[0013] Furthermore, the clamps are arranged symmetrically at both ends of the fiber optic sensor.

[0014] Furthermore, the pressure plate has a buffer pad on the contact surface of the locking bolt.

[0015] This utility model has at least the following advantages and beneficial effects: by opening a first limiting groove on the mounting beam, a reference for placing the fiber optic sensor is provided, and the axial deformation space of the mounting beam is reserved through the groove. Combined with a hoop that can be adjusted along the axial direction of the mounting beam and a pressure plate pushed by locking bolts, the positioning of the fiber optic sensor, the free deformation transmission of the mounting beam, the adaptation and stable fixing of sensors of different lengths are realized. This effectively avoids calibration errors caused by fiber optic sensor offset, limited deformation of the mounting beam, and insecure fixing, and improves calibration accuracy and tooling adaptability. Attached Figure Description

[0016] Figure 1 This utility model provides a schematic diagram of the calibration assembly structure of a fiber optic sensor calibration fixture.

[0017] Figure 2This is a schematic diagram of the structure of a fiber optic sensor calibration fixture provided by this utility model.

[0018] Figure 3 This is a top view of a fiber optic sensor calibration fixture provided by this utility model.

[0019] Figure 4 This is a schematic diagram of the mounting beam in a fiber optic sensor calibration fixture provided by this utility model.

[0020] Figure 5 A schematic diagram of the hoop structure in a fiber optic sensor calibration fixture provided by this utility model.

[0021] Figure 6 This is a schematic diagram of the structure of an optical fiber sensor in an optical fiber sensor calibration fixture provided by this utility model.

[0022] Reference numerals: 1-Mounting beam, 10-First limiting groove, 11-Through groove, 12-Second limiting groove, 13-Strip hole, 14-Limiting hole, 2-Hoop, 21-Gantry, 22-Base plate, 23-Slide rail, 3-Pressure plate, 30-Card slot, 31-Positioning protrusion, 4-Fiber optic sensor. Detailed Implementation

[0023] The specific implementation method is described below with reference to the accompanying drawings.

[0024] Example like Figures 1 to 6As shown, this embodiment mainly discloses a fiber optic sensor calibration fixture, including a mounting beam 1. The mounting beam 1 has a first limiting groove 10 for placing the fiber optic sensor 4. The first limiting groove 10 has a through slot 11 that provides space for the axial deformation of the mounting beam 1. Hoops 2 are movably sleeved on the mounting beam 1 at both ends of the axial direction of the fiber optic sensor 4. A pressure plate 3 is slidably connected in the hoop 2. The hoop 2 is threaded with a locking bolt for abutting against the pressure plate 3 to press and fix the fiber optic sensor 4 in the first limiting groove 10. Specifically, the calibration fixture uses the mounting beam 1 as the core load-bearing foundation. The first limiting groove 10 provides a reference space for the horizontal placement of the fiber optic sensor 4. The through groove 11 can be a number of strip holes evenly spaced along the axial direction of the mounting beam 1, which can reserve sufficient space for the axial tensile or compressive deformation of the mounting beam 1 during the calibration process. This ensures the free deformation of the mounting beam 1 and ensures that the deformation of the mounting beam 1 can be accurately transmitted to the fiber optic sensor 4. The clamp 2 can be adjusted in position along the axial direction of the mounting beam 1 to accommodate fiber optic sensors 4 of different lengths. The pressure plate 3, which is slidably connected inside the clamp 2, can move vertically under the push of the locking bolt, abutting against the pressure plate 3 and pressing and fixing the fiber optic sensor 4 in the first limiting groove 10 of the mounting beam 1. This prevents the fiber optic sensor 4 from slipping during the calibration loading process, realizes the positioning and fixing of the fiber optic sensor 4, and effectively avoids calibration errors caused by the placement offset of the fiber optic sensor 4, the limited deformation of the mounting beam 1, or the insecure fixing.

[0025] Furthermore, in a specific implementation, a second limiting groove 12 is provided on the side wall of the mounting beam 1 provided in this embodiment of the present invention. The hoop 2 is slidably connected within the second limiting groove 12. The inner walls at both ends of the second limiting groove 12 restrict the hoop 2 from moving away from each other, providing sliding guidance and lateral limiting for the hoop 2. This ensures that the hoop 2 can only slide along the axial direction of the second limiting groove 12 and cannot undergo lateral offset or rotation perpendicular to the axial direction. This ensures that the hoop 2 always adjusts its spacing along the axial direction of the fiber optic sensor 4, guaranteeing the accuracy of the fixed position of the hoop 2 on both ends of the fiber optic sensor 4. This provides guidance for the uniform force distribution and accurate transmission of calibration displacement of the subsequent fiber optic sensor 4, further improving the stability of the tooling adjustment process.

[0026] Furthermore, in a specific implementation, a slot 13 is provided axially within the second limiting groove 12 provided in this embodiment of the present invention, and the hoop 2 is threadedly connected to an adjusting bolt that abuts against the slot 13 to lock the relative position of the hoop 2 and the mounting beam 1. Specifically, the slot 13 allows the hoop 2 to slide freely along the length of the slot 13 to accommodate fiber optic sensors 4 with different gauge lengths; and the adjusting bolt threaded on the hoop 2, after the hoop 2 is adjusted to the target position, is tightened so that its end abuts tightly against the inner wall of the slot 13, using friction to lock the relative position of the hoop 2 and the mounting beam 1, preventing the hoop 2 from shifting due to vibration or loading force during the calibration process.

[0027] Furthermore, in a specific implementation, a limiting hole 14 is provided in the second limiting groove 12 provided in this embodiment of the utility model. The limiting hole 14 is connected to a washer for limiting the proximity of the clamps 2 by a screw with a threaded connection. Specifically, the washer is a metal washer, which is fitted onto the screw and forms a rigid limiting contact with the clamps 2, thereby limiting the proximity of the two clamps 2. This can prevent the clamps 2 from getting too close to the fiber optic sensor 4 due to operational errors or vibration during calibration loading, thus preventing damage to the fiber optic sensor 4. At the same time, it ensures that the distance between the two clamps 2 is always not less than the minimum gauge length of the sensor, avoiding strain calculation deviation caused by an excessively small gauge length. This not only improves the safety of tooling use but also ensures the stability of the calibration gauge length, further enhancing the reliability of the calibration data.

[0028] Furthermore, in a specific implementation, the bottom of the pressure plate 3 provided in this embodiment of the present invention is provided with positioning protrusions 31 that abut against the inner walls of the two sides of the first limiting groove 10 perpendicular to the axial direction. When the pressure plate 3 is engaged with the first limiting groove 10, the positioning protrusions 31 and the inner walls of the two sides of the first limiting groove 10 perpendicular to the axial direction form a tight abutment, thereby limiting the movement trajectory of the pressure plate 3, preventing the pressure plate 3 from shifting laterally, ensuring the accurate pressing position of the pressure plate 3, and reducing the calibration error caused by the offset of the pressure plate 3.

[0029] Furthermore, in a specific implementation, the pressure plate 3 provided in this embodiment of the present invention has a slot 30 for engaging with the fiber optic sensor 4. Specifically, based on the vertical pressing of the pressure plate 3, the movement of the fiber optic sensor 4 is further restricted in the horizontal direction (axial and transverse directions of the mounting beam 1), thereby improving the fixing reliability of the fiber optic sensor 4.

[0030] Furthermore, in a specific implementation, the aforementioned clamp 2 provided in this embodiment of the present invention includes a bolted gantry 21 and a base plate 22, with a slide rail 23 inside the gantry 21 that slidably engages with the pressure plate 3. Specifically, the gantry 21 is U-shaped, and the gantry 21 is detachably connected to the base plate 22 by bolts; the slide rail 23 is used to form a sliding engagement with the pressure plate 3, guiding the pressure plate 3 to slide vertically along the slide rail 23, preventing the pressure plate 3 from shifting or jamming during its up-and-down movement.

[0031] Furthermore, in specific implementations, the aforementioned clamp 2 provided in this embodiment of the invention is symmetrically arranged at both ends of the fiber optic sensor 4. This ensures that the fixing force and supporting force on both ends of the fiber optic sensor 4 are balanced, preventing uneven deformation of the fiber optic sensor 4 due to unilateral force misalignment. It should be noted that the central axis of the fiber optic sensor 4 coincides with the deformation axis of the mounting beam 1, ensuring that the axial deformation of the mounting beam 1 is completely and synchronously transmitted to the fiber optic sensor 4, further improving the accuracy of displacement transmission during calibration.

[0032] Furthermore, in a specific implementation, the pressure plate 3 provided in this embodiment of the present invention has a buffer pad on the contact surface of the locking bolt. When the locking bolt is tightened, the elastic deformation of the buffer pad absorbs the local pressure applied by the locking bolt, avoiding hard contact between the bolt and the pressure plate 3, and effectively alleviating the instantaneous pressure when the locking bolt is tightened.

Claims

1. An optical fiber sensor calibration fixture, characterized by, The device includes a mounting beam (1), which has a first limiting groove (10) for placing an optical fiber sensor (4). The first limiting groove (10) has a through slot (11) for providing space for the axial deformation of the mounting beam (1). Hoops (2) are movably sleeved on the mounting beam (1) at both ends of the optical fiber sensor (4). A pressure plate (3) is slidably connected in the hoop (2). The hoop (2) is threaded with a locking bolt for abutting against the pressure plate (3) to press and fix the optical fiber sensor (4) in the first limiting groove (10).

2. The fiber optic sensor calibration fixture of claim 1, wherein, The mounting beam (1) has a second limiting groove (12) on its side wall. The hoop (2) is slidably connected to the second limiting groove (12). The inner walls at both ends of the second limiting groove (12) restrict the hoop (2) from moving away from each other.

3. The fiber optic sensor calibration fixture of claim 2, wherein, The second limiting groove (12) has a slot (13) axially formed inside, and the hoop (2) is threadedly connected with an adjusting bolt that abuts against the slot (13) to lock the relative position of the hoop (2) and the mounting beam (1).

4. The fiber optic sensor calibration fixture of claim 2, wherein, The second limiting groove (12) has a limiting hole (14), and the limiting hole (14) is connected to a washer for limiting the hoop (2) to approach each other by a screw connected by a thread.

5. The fiber optic sensor calibration fixture of claim 1, wherein, The bottom of the pressure plate (3) is provided with positioning protrusions (31) that abut against the inner walls of the two sides of the first limiting groove (10) perpendicular to the axial direction.

6. The fiber optic sensor calibration fixture of claim 1, wherein, The pressure plate (3) has a slot (30) for engaging with the fiber optic sensor (4).

7. The fiber optic sensor calibration fixture of claim 1, wherein, The hoop (2) includes a bolted gantry (21) and a base plate (22), and the gantry (21) is provided with a slide rail (23) that is slidably engaged with the pressure plate (3).

8. The fiber optic sensor calibration fixture of claim 1, wherein, The clamp (2) is symmetrically arranged at both ends of the fiber optic sensor (4).

9. The fiber optic sensor calibration fixture of claim 1, wherein, The pressure plate (3) has a buffer pad on the contact surface of the locking bolt.

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