A pendulum force hammer calibration device

Abstract

The application discloses a pendulum type force hammer calibration device in the technical field of force hammer calibration, which comprises a base, a guide rail arranged on the base, a fixing frame, a suspension cable arranged on the fixing frame, a mass block suspended by the suspension cable, an acceleration sensor arranged on the back of the mass block, a movable frame arranged in front of the fixing frame, the bottom of the movable frame being arranged on the guide rail and the movable frame being movable along the guide rail, a positioning arm, one end of the positioning arm being hinged to the movable frame and the other end of the positioning arm being provided with an auxiliary unit, the positioning arm being rotatable in a plane perpendicular to the front of the mass block, a positioning assembly for locking the positioning arm, a movable arm, one end of the movable arm being hinged to the movable frame and the other end of the movable arm being provided with a clamp, the clamp being used for clamping a measured force hammer, and the rotation plane of the movable arm being parallel to the rotation plane of the positioning arm, wherein the auxiliary unit is used for clamping or adsorbing the clamp. The measurement process of the force hammer calibration device can be repeatedly performed multiple times, and the consistency of measurement conditions is high, so that the measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of force hammer calibration technology, and in particular to a pendulum-type force hammer calibration device. Background Technology

[0002] The purpose of Experimental Modal Analysis (EMA) is to measure the modal parameters of a system, namely modal frequencies, modal damping, mode shapes, modal stiffness, and modal mass. These modal parameters describe the vibration characteristics of the system.

[0003] A crucial step in modal analysis testing is applying a dynamic excitation to the structure. This excitation can be applied to a single point on the structure or simultaneously to multiple points. The goal of applying the excitation is to induce vibration within a selected frequency range, requiring that both the applied dynamic force and the structure's response to the excitation be measurable. The data analysis system digitizes the collected signals and uses them to calculate the frequency response function, which forms the basis for estimating modal parameters. Clearly, excitation is a vital component of the modal testing process; it induces vibration in the structure, a necessary condition for experimentally studying the dynamic characteristics of any object.

[0004] Modal testing often requires the use of a force hammer to provide excitation. However, force hammers need to be calibrated during routine maintenance or before use. There are two existing impact force calibration devices, both primarily based on the collision between the force hammer and a mass block: one involves hand-holding the force hammer to strike the mass block, and the other involves the mass block falling freely and impacting the force hammer. However, both methods have low repeatability and poor accuracy. Summary of the Invention

[0005] This application provides a pendulum-type force hammer calibration device, which solves the problems of low repeatability and poor accuracy of existing force hammer calibration devices, and improves calibration accuracy and consistency.

[0006] This application provides a pendulum-type force hammer calibration device, including: A base, on which a guide rail is provided; A fixed frame, the bottom of which is fixed to the base, is provided with a suspension cable on the fixed frame, a mass block is suspended by the suspension cable, and an acceleration sensor is installed on the back of the mass block; A movable frame is located directly in front of the fixed frame, and the bottom of the movable frame is mounted on the guide rail and the movable frame can move along the guide rail; A positioning arm, one end of which is hinged to the movable frame and the other end is provided with an auxiliary unit. The positioning arm can rotate in a plane perpendicular to the front of the mass block. A positioning component for locking the positioning arm; The movable arm has one end hinged to the movable frame and the other end provided with a clamp for holding the hammer to be measured. The rotation plane of the movable arm is parallel to the rotation plane of the positioning arm. The auxiliary unit is used to clamp or absorb the clamp.

[0007] The beneficial effects of the above embodiments are as follows: the mass block of the force hammer calibration device can swing back and forth, a standard accelerometer is installed on the mass block, the force hammer to be measured is fixed on the fixture, the movable arm is vertically downward, and the hammer head lightly touches the mass block and is coaxial; the angle of the positioning arm is adjusted and locked by the positioning component; the movable arm is rotated, the fixture on the movable arm is connected to the auxiliary unit on the positioning arm and then released, the movable arm rotates, and the lower end of the force hammer will collide with the mass block, thereby measuring the acceleration value 'a' of the mass block by the standard accelerometer, and the force value of the force hammer to be measured can be calculated by F=ma, and the calibration is performed by repeating the test multiple times. The measurement process of this force hammer calibration device can be repeated many times and the measurement conditions are highly consistent, thereby improving the measurement accuracy.

[0008] Based on the above embodiments, this application can be further improved as follows: In one embodiment of this application, the fixing frame includes two fixed columns and an adjusting beam. Each of the two fixed columns has a sliding groove on its opposite side. Both ends of the adjusting beam are connected to the sliding grooves, and the suspension cable is connected to the adjusting beam. Both ends of the adjusting beam are connected to the sliding grooves by screws, allowing the height of the adjusting beam to be adjusted up and down along the sliding grooves, thus facilitating the adjustment of the mass block's height.

[0009] In one embodiment of this application, the fixing frame further includes an adjusting plate. A second sliding groove is formed on the bottom surface of the adjusting beam. The adjusting plate is connected to the second sliding groove, and the suspension cable is connected to the adjusting plate. The adjusting plate is connected to the second sliding groove by screws, and its position can be adjusted left and right along the second sliding groove to facilitate adjustment of the mass block's position.

[0010] In one embodiment of this application, the movable frame includes two movable columns and a mounting beam. Two guide rails are arranged in parallel. The bottoms of the two movable columns are respectively connected to the guide rails. Slide grooves are provided on opposite sides of the two movable columns. Both ends of the mounting beam are connected to the slide grooves. One end of the positioning arm is hinged to one of the movable columns, and the other end of the movable arm is hinged to the mounting beam. The bottoms of the two movable columns are respectively connected to the guide rails with screws, facilitating adjustment of the distance between the movable frame and the fixed frame. Both ends of the mounting beam are respectively connected to the slide grooves with screws, allowing the height of the mounting beam to be adjusted up and down along the slide grooves, thus facilitating adjustment of the height of the hammer to achieve coaxial contact with the mass block.

[0011] In one embodiment of this application, a movable arm shaft is provided at the bottom of the mounting beam, and the upper end of the movable arm is connected to the movable arm shaft. The movable arm is designed to rotate freely around the shaft as much as possible.

[0012] In one embodiment of this application, the movable column is provided with a positioning arm shaft, and the upper end of the positioning arm is connected to the positioning arm shaft. The positioning arm is designed to rotate freely around the shaft as much as possible.

[0013] In one embodiment of this application, the positioning component includes a dial and a fastening screw. The dial is fixed to the movable column, and an arc-shaped through hole is formed on the dial. The fastening screw passes through the arc-shaped through hole and connects to the positioning arm. A washer is provided on the fastening screw between the dial and the positioning arm to lock the fastening screw at a certain point on the dial, thereby locking the positioning arm. The dial is provided with graduations to facilitate adjustment of the rotation angle of the positioning arm during different tests, thereby adjusting the impact force during impact.

[0014] In one embodiment of this application, the auxiliary unit includes an electromagnet used to attract a clamp. The movable arm is fixed in a specific position by the clamp attracted by the de-energized electromagnet. Upon impact, the clamp is released, allowing the movable arm to rotate freely around its axis due to gravity, and the measured hammer strikes the mass block.

[0015] In one embodiment of this application, the auxiliary unit further includes an electromagnet controller, which is equipped with a power switch and a release switch. When the release switch is pressed, the auxiliary unit releases the clamp, facilitating the operation of the electromagnet to attract or release the clamp.

[0016] In one embodiment of this application, the electromagnet is a de-energized electromagnet. The electromagnet is only energized when the release switch is pressed, which is energy-saving and environmentally friendly.

[0017] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. The measurement process of this force hammer calibration device can be repeated multiple times with high consistency of measurement conditions, thereby improving measurement accuracy; 2. The distance between the fixed frame and the movable frame of the hammer calibration device is adjustable, which makes it easy to adjust the distance between the hammer and the mass block, so that the hammer and the mass block make coaxial contact when they touch. 3. The adjusting beam and mounting beam of the hammer calibration device can be easily adjusted in position, thereby facilitating coaxial contact between the hammer and the mass block. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the axial view structure of a pendulum-type force hammer calibration device according to the present invention; Figure 2 for Figure 1 Enlarged view of region I in the middle; Figure 3 for Figure 1 Enlarged view of region II; Figure 4 This is a front view schematic diagram of a pendulum-type force hammer calibration device according to the present invention; Figure 5 for Figure 4 Schematic diagram of the cross section along line AA; Figure 6 for Figure 4 A schematic diagram of the cross section along line BB.

[0020] The components include: 1. Base, 11. Guide rail, 2. Fixing frame, 21. Fixing column, 22. Adjusting beam, 23. Adjusting plate, 24. Slide 1, 25. Slide 2, 26. Suspension cable, 3. Movable frame, 31. Movable column, 32. Mounting beam, 33. Slide 3, 4. Positioning arm, 5. Positioning assembly, 51. Dial, 52. Fastening screw, 6. Movable arm, 61. Clamp, 62. Force hammer, 7. Mass block, 8. Accelerometer, 9. Auxiliary unit, 91. Electromagnet, 92. Electromagnet controller, 93. Power switch, and 94. Release switch. Detailed Implementation

[0021] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of this invention, it should be noted that the terms "vertical," "outer peripheral surface," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, terms such as "vertical" do not imply that a component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. Similarly, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0025] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] In the description of this invention, the illustrative expressions of the terms used above do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this invention, as well as the features of those different embodiments or examples, without contradiction.

[0027] This application provides a pendulum-type force hammer calibration device, which solves the problems of low repeatability and poor accuracy in the prior art of force hammer calibration devices, and improves calibration accuracy and consistency.

[0028] The technical solution in this application is to solve the above problems, and the overall approach is as follows: Example: like Figure 1-6 As shown, a pendulum-type force hammer calibration device includes: a base 1, a fixed frame 2, a movable frame 3, a positioning arm 4, a positioning component 5, a movable arm 6, a mass block 7 (back side), an acceleration sensor 8, and an auxiliary unit 9.

[0029] Two guide rails 11 are installed in parallel on the base 1.

[0030] The fixed frame 2 includes two fixed columns 21, an adjusting beam 22 and an adjusting plate 23. The bottom of the two fixed columns 21 is fixedly installed on the base 1. The fixed columns 21 are respectively provided with sliding grooves 24 on opposite sides. The two ends of the adjusting beam 22 are respectively connected to the sliding grooves 24 by screws. The bottom surface of the adjusting beam 22 is provided with a sliding groove 25. The adjusting plate 23 is connected to the sliding groove 25 by screws. The end of the suspension cable 26 is fixed to the adjusting plate 23. The suspension cable 26 suspends a mass block 7. The mass block 7 can swing freely back and forth. An acceleration sensor 8 is installed on the back of the mass block 7.

[0031] The movable frame 3 is located directly in front of the fixed frame 2. The guide rail 11 is perpendicular to the plane of the fixed frame 2. The movable frame 3 includes two movable columns 31 and a mounting beam 32. The bottom of the two movable columns 31 is connected to the guide rail 11 by screws and can move along the guide rail 11. The two movable columns 31 are respectively provided with sliding grooves 33 on opposite sides. The two ends of the mounting beam 32 are respectively connected to the sliding grooves 33 by screws. A positioning arm shaft is provided on one side of the movable column 31, and a movable arm shaft is provided at the bottom of the mounting beam 32.

[0032] The upper end of the positioning arm 4 is connected to the positioning arm shaft, and the lower end is provided with an auxiliary unit 9. The positioning arm 4 can rotate in a plane perpendicular to the front of the mass block 7. The upper end of the movable arm 6 is connected to the movable arm shaft, and the lower end is provided with a clamp 61. The clamp 61 is used to clamp the measured force hammer 62. The rotation plane of the movable arm 6 is parallel to the rotation plane of the positioning arm 4.

[0033] The positioning component 5 includes a fan-shaped dial 51 and a fastening screw 52. The fan-shaped dial 51 is fixed to a movable column 31 on one side. The dial 51 has an arc-shaped through hole concentric with the axis of the positioning arm 4. The fastening screw 52 passes through the arc-shaped through hole and connects to the positioning arm 4. The positioning arm 4 has a corresponding threaded hole. A washer is provided on the fastening screw 52 between the dial 51 and the positioning arm 4 to lock the fastening screw 52 at a certain point on the dial 51, thereby locking the positioning arm 4. The dial 51 is provided with an arc-shaped scale, which facilitates the adjustment of the rotation angle of the positioning arm 4 during different tests and adjusts the impact force during impact.

[0034] The auxiliary unit 9 is used to clamp or attract the clamp 61. In this example, the auxiliary unit 9 includes a de-energized electromagnet 91 and an electromagnet controller 92. The electromagnet 91 is used to attract the clamp 61, and the electromagnet controller 92 is equipped with a power switch 93 and a release switch 94. The auxiliary unit 9 can also use a common tooling clamp 61, which can be manually released, as long as it can achieve the function of clamping and releasing the clamp 61.

[0035] The calibration process for the force hammer is as follows: The hammer 62 to be tested is fixed on the clamp 61, with the movable arm 6 pointing vertically downward. The position of the movable frame 3 (front and back), the horizontal position adjustment plate 23 of the mass block 7, and the vertical position adjustment beam 22 can be adjusted so that the hammer head of the hammer 62 lightly touches the mass block 7 and is coaxial. The angle of the positioning arm 4 is adjusted so that the movable arm 6 clamp 61 is attracted to the de-energized electromagnet 91. When the electromagnet release switch 94 is pressed, the movable arm 6 will be released, and the hammer 62 will collide with the mass block 7. The acceleration value a of the mass block 7 can be measured by a standard accelerometer. The force value of the hammer 62 to be tested can be calculated by F=ma. Repeat the test multiple times for calibration.

[0036] The technical solutions described in the embodiments of this application have at least the following technical effects or advantages: 1. The measurement process of this force hammer calibration device can be repeated multiple times with high consistency of measurement conditions, thereby improving measurement accuracy; 2. The distance between the fixed frame and the movable frame of the hammer calibration device is adjustable, which makes it easy to adjust the distance between the hammer and the mass block, so that the hammer and the mass block make coaxial contact when they touch. 3. The adjusting beam and mounting beam of the hammer calibration device can be easily adjusted in position, thereby facilitating coaxial contact between the hammer and the mass block.

[0037] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A pendulum-type force hammer calibration device, characterized in that, include: A base, on which a guide rail is provided; A fixed frame is provided, the bottom of which is fixed to the base. A suspension cable is provided on the fixed frame, and a mass block is suspended by the suspension cable. An acceleration sensor is installed on the back of the mass block. The fixed frame includes two fixed columns and an adjusting beam. A sliding groove is provided on the opposite side of the two fixed columns. Both ends of the adjusting beam are connected to the sliding groove. The suspension cable is connected to the adjusting beam. A movable frame is located directly in front of the fixed frame, and the bottom of the movable frame is mounted on the guide rail and the movable frame can move along the guide rail; A positioning arm, one end of which is hinged to the movable frame and the other end is provided with an auxiliary unit. The positioning arm can rotate in a plane perpendicular to the front of the mass block. A positioning component for locking the positioning arm; The movable arm has one end hinged to the movable frame and the other end provided with a clamp for holding the hammer to be measured. The rotation plane of the movable arm is parallel to the rotation plane of the positioning arm. The auxiliary unit is used to hold or absorb the clamp.

2. The pendulum-type force hammer calibration device according to claim 1, characterized in that: The fixing frame also includes an adjusting plate, and the bottom surface of the adjusting beam is provided with a second sliding groove. The adjusting plate is connected to the second sliding groove, and the suspension cable is connected to the adjusting plate.

3. The pendulum-type force hammer calibration device according to claim 1, characterized in that: The movable frame includes two movable columns and a mounting beam. Two guide rails are arranged in parallel. The bottoms of the two movable columns are respectively connected to the guide rails. The two movable columns are respectively provided with sliding grooves on opposite sides. The two ends of the mounting beam are respectively connected to the sliding grooves. One end of the positioning arm is hinged to the movable column, and the other end of the movable arm is hinged to the mounting beam.

4. The pendulum-type force hammer calibration device according to claim 3, characterized in that: The bottom of the mounting beam is provided with a movable arm shaft, and the upper end of the movable arm is connected to the movable arm shaft.

5. The pendulum-type force hammer calibration device according to claim 4, characterized in that: The movable column is equipped with a positioning arm shaft, and the upper end of the positioning arm is connected to the positioning arm shaft.

6. The pendulum-type force hammer calibration device according to claim 5, characterized in that: The positioning component includes a dial and a fastening screw. The dial is fixed to the movable column. An arc-shaped through hole is provided on the dial. The fastening screw passes through the arc-shaped through hole and is connected to the positioning arm.

7. The pendulum-type force hammer calibration device according to claim 1, characterized in that: The auxiliary unit includes an electromagnet, which is used to attract the clamp.

8. The pendulum-type force hammer calibration device according to claim 7, characterized in that: The auxiliary unit also includes an electromagnet controller, which is equipped with a power switch and a release switch.

9. The pendulum-type force hammer calibration device according to claim 8, characterized in that: The electromagnet used is a de-energized electromagnet.

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