A kit for detecting bolt loosening

Abstract

The utility model discloses a kind of accessories for detecting bolt loosening, belong to mechanical detection field.The accessory includes body, detection head, elastic detection piece and baffle with observation window.First, second limiting step is equipped in the body interior, detection head is slidably assembled along axial direction, and its top is equipped with the elastic detection piece with radial detection strip, and detection strip is abutted to the inside of baffle with inclination greater than 60 ° and less than 80 °.When bolt loosens, its axial displacement promotes detection head to move, forces detection strip to elastically bend deformation, so that its part in observation window produces significant radial position change, to amplify small displacement as intuitive visual signal.The utility model is highly integrated, compact and reliable, without power supply and complex transmission mechanism, and the loosening state is realized quickly and intuitively by pure mechanical mode, and it is especially suitable for bolt inspection in harsh industrial environment.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical testing technology, specifically relating to an accessory for detecting loose bolts. Background Technology

[0002] Bolted connections, as one of the most basic and widely used connection methods in mechanical equipment and engineering structures, directly determine the safety of connected components and the service life of the overall structure based on the reliability of their fastening condition. In critical fields such as bridges, wind power, rail transportation, heavy machinery, and aerospace, bolts may slowly loosen due to long-term exposure to alternating loads, vibration, impact, or temperature stress. If this loosening is not detected and addressed in time, it will gradually evolve from a small loss of preload to connection failure, potentially leading to serious structural damage or safety accidents. Therefore, convenient and effective monitoring of the bolted connection status in critical areas is of significant engineering importance.

[0003] Currently, common methods for detecting or judging bolt loosening mainly have the following limitations:

[0004] 1. Methods relying on manual experience: such as using a torque wrench for re-tightening checks, identifying by tapping and listening to the sound, or observing whether manually drawn anti-loosening markings are misaligned. These methods are highly dependent on the operator's skills and experience, are subjective, cannot achieve quantitative detection, and are extremely insensitive to early and minor loosening, making them prone to missed detections.

[0005] 2. Methods based on electronic sensing technology: These methods employ piezoelectric sensors, fiber optic gratings, ultrasonic sensors, or strain gauges to indirectly assess loosening by monitoring changes in bolt axial force or structural strain. While these methods offer high accuracy, they typically require complex signal acquisition modules, power supply units, and data processing systems, resulting in high overall costs and cumbersome deployment and installation. Furthermore, in harsh industrial environments characterized by humidity, dust, strong electromagnetic interference, or severe vibration, the reliability and long-term stability of their electronic systems face significant challenges.

[0006] 3. Simple mechanical measurement methods: For example, using a dial indicator or micrometer to directly measure the displacement of the bolt head relative to the connecting plate. This method is straightforward in principle, but the readings are usually not intuitive, and small axial displacements are difficult to clearly and magnify for display, which is not conducive to rapid inspection and long-distance observation.

[0007] In summary, existing technologies struggle to achieve a good balance between simplicity, intuitiveness, and economy in bolt loosening detection. The market urgently needs a bolt condition monitoring method that is suitable for harsh industrial environments, requires no external energy, has a simple and compact structure, is low-cost, and provides clear and rapid qualitative assessment of detection results to meet the on-site needs of daily inspections and rapid troubleshooting of large numbers of bolts. Utility Model Content

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution.

[0009] An accessory for detecting loose bolts includes a body with an internal cavity. The body has a first limiting step and a second limiting step. Both the first limiting step and the second limiting step have through holes in between. The first limiting step is located at the bottom of the body. The second limiting step is located inside the cavity and divides the cavity from top to bottom into a display cavity and a detection cavity. The detection cavity has a baffle, and the baffle has an observation window extending radially along the body.

[0010] A detection head is slidably mounted axially within the detection cavity. The bottom of the detection head passes through a through hole in the first limiting step, and the top passes through a through hole in the second limiting step. A detection element made of elastic material is mounted on the top of the detection head. The detection element has several detection plates corresponding to the observation window. The angle α between the detection plates and the axis of the detection head is greater than 60° and less than 80°. The free end of the detection plate abuts against the inner surface of the baffle. When the detection head moves axially, the free end of the detection plate slides along the baffle, and the portion of it located within the observation window undergoes a significant radial position change to indicate the amount of displacement.

[0011] Furthermore, the detection head includes a guide portion that is slidably assembled with the body, and a contact portion for contacting the head of the bolt to be tested is assembled within the guide portion via a bearing.

[0012] Furthermore, a stop is provided on the outer periphery of the guide portion, and a first spring and a second spring are respectively provided on the upper and lower sides of the stop along the axial direction of the guide portion. The upper end of the first spring abuts against the second limiting step, and the lower end of the second spring abuts against the first limiting step, thereby keeping the detection head floating in the body.

[0013] Furthermore, the bottom of the contact portion protrudes or is flush with the end face of the first limiting step facing the bolt to be tested.

[0014] Furthermore, the bottom of the contact portion is provided with a centering groove for guiding the bolt head to center. The centering groove has a guide surface that gradually expands outward from the center. During testing, the outer edge of the bolt head to be tested abuts against the guide surface to achieve centering.

[0015] Furthermore, the baffle has a radially extending groove on the side facing the detection piece for each observation window, and the free end of the detection piece is accommodated in the corresponding groove.

[0016] Compared with the prior art, this application has the following beneficial technical effects:

[0017] 1. The axial movement of the detection head directly drives the elastic detection plate, causing a significant radial position change at the free end of the plate within the observation window. This change is clearly visible, requiring no electronic sensors or reading instruments, is unaffected by electromagnetic interference, and is resistant to high and low temperatures, humidity, and vibration shock, making it suitable for various harsh industrial environments.

[0018] 2. The detection mechanism, displacement conversion mechanism and indicator window are all integrated into the internal cavity of a single body. The structure is compact and the number of parts is small, which not only reduces manufacturing costs, but also improves the structural compactness of the entire component and its adaptability in small spaces. At the same time, it reduces the number of failure points and improves the reliability of long-term use.

[0019] 3. By observing the displacement of the test piece in the observation window area, the looseness of the bolts can be qualitatively judged (such as "normal" or "out of limit"), which greatly improves the efficiency of on-site inspection and rapid troubleshooting.

[0020] 4. The floating structure can adaptively compensate for uneven mounting surfaces or slight bolt misalignment, ensuring contact stability. The guide surface of the centering groove can adaptively guide and accommodate bolt heads of different sizes, ensuring the consistency of the inspection benchmark and the accuracy of the measurement results. Attached Figure Description

[0021] Figure 1 This is a 3D view of the accessories.

[0022] Figure 2 This is a plan view of the component under inspection.

[0023] Figure 3 This is a sectional view of the accessory.

[0024] Figure 4 This is a structural diagram of the component located in the display cavity.

[0025] Figure 5 This is a structural diagram of the back of the baffle.

[0026] The following is an explanation of the reference numerals in the attached figures:

[0027] 10. Body; 11. First limiting step; 12. Second limiting step; 13. Baffle; 14. Observation window; 15. Reference scale line; 16. Slide groove;

[0028] 20. Detection head; 21. Guide part; 22. Side flange; 23. Contact part; 24. Centering groove; 25. First spring; 26. Second spring;

[0029] 30. Test piece; 31. Test strip;

[0030] 40. Bolt; 41. Plate; 42. Fixing device. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] In the following embodiments, the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] In the description of this utility model, it should be understood that the terms such as center, longitudinal, transverse, length, width, thickness, upper, lower, front, back, left, right, vertical, horizontal, top, bottom, inner, outer, clockwise, and counterclockwise, indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description; therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features shown. In the description of this utility model, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," etc., should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] This application provides an accessory for detecting bolt loosening. This accessory functions as a stand-alone detection module, as referenced... Figure 2 When in use, it is necessary to use an external fixing device 42 (such as a C-clamp, quick clamp or other form of clamping tool) to securely install it on the plate 41 connected to the bolt 40 to be tested, and align the bottom of the accessory with the head of the bolt 40.

[0035] refer to Figures 1 to 5 The accessory includes a body 10, which is a cylindrical or square-shaped structure with a through-cavity. Inside the body 10, there is a first limiting step 11 and a second limiting step 12. Both steps have through holes at their centers and are coaxially arranged. The first limiting step 11 is located at the bottom of the body 10, and the second limiting step 12 is located at a higher position inside the cavity, thus roughly dividing the cavity into an upper display cavity and a lower detection cavity. A baffle 13 is fixedly installed inside the detection cavity. The baffle 13 has at least one elongated opening extending radially (i.e., horizontally) along the body 10. This opening contains an observation window 14 made of a transparent or semi-transparent material (such as acrylic), allowing the interior of the display cavity to be seen from outside the body 10.

[0036] Inside the detection chamber, a detection head 20 is slidably mounted along the axial direction (i.e., vertical direction) of the body 10. The bottom of the detection head 20 passes downward through the central through hole of the first limiting step 11, and its top passes upward through the central through hole of the second limiting step 12. The detection head 20 can slide axially relative to the body 10.

[0037] A detection element 30 made of an elastic material is mounted on the top of the detection head 20. This elastic material can be phosphor bronze, spring steel, or engineering plastics with good elasticity. The detection element 30 has several radially extending detection plates 31, the number and position of which correspond one-to-one with the observation windows 14 on the baffle 13. These detection plates 31 form an acute angle α with the axis (i.e., the vertical direction) of the detection head 20. The design range of this angle α is greater than 60° and less than 80°. The purpose of this angle α is that when the detection head 20 undergoes a small vertical displacement, the free end of the detection plate 31 will generate a large horizontal motion component.

[0038] The free ends of all the detection pieces 31 (i.e., the ends furthest from the center of the detection head 20) continuously abut against the inner surface of the baffle 13. The baffle 13 provides a reaction force and a sliding plane for the free ends of the detection pieces 31. On the side of the baffle 13 facing the detection element 30, opposite each observation window 14, a radially extending groove 16 can preferably be machined. The free ends of the detection pieces 31 can be accommodated and confined to slide within this groove 16, which ensures a more stable motion trajectory and prevents lateral drift.

[0039] When bolt 40 loosens, causing a slight axial (vertical) displacement of its head, it pushes the detection head 20 to overcome internal resistance (such as spring force) and produce a corresponding axial movement. The movement of the detection head 20 causes the elastic detection piece 31 at its top to move along with it. Because the free end of the detection piece 31 is confined to the surface of the baffle 13 (or within the groove 16), the axial displacement of the detection head 20 forces the angled detection piece 31 to undergo elastic bending deformation. This deformation is directly manifested as the free end of the detection piece 31 sliding along the surface of the baffle 13. Simultaneously, the radial position of the portion of the detection piece 31 located below the observation window 14, visible within the observation window 14, will change significantly. For example, when the detection head 20 moves upward, the portion of the detection piece 31 within the observation window 14 will extend outward, allowing the observer to clearly see the movement effect. For ease of judgment, static reference scale lines 15 can be drawn on the transparent baffle 13 next to the observation window 14 or on the outer wall of the body 10 to indicate the safe range and danger threshold.

[0040] Furthermore, the detection head 20 includes a guide portion 21 that slides with the body 10, the outer diameter of which is precisely matched with the through holes of the first and second limiting steps 12 to ensure smooth movement; a contact portion 23 is assembled inside the guide portion 21 through a bearing, the contact portion 23 can rotate freely, so that it can reduce friction when in contact with the head of the bolt 40 and adapt to possible rotation of the head of the bolt 40.

[0041] To improve the stability and adaptability of the detection, a radially protruding retaining edge 22 can be provided around the outer periphery of the guide portion 21. A first spring 25 is installed between the upper side of the retaining edge 22 and the lower surface of the second limiting step 12, and a second spring 26 is installed between the lower side of the retaining edge 22 and the upper surface of the first limiting step 11. These two springs allow the detection head 20 to float in a balanced position under natural conditions, forming a "floating" state. This design allows the contact portion 23 to adaptively conform to the head of the bolt 40 and has the ability to compensate for different preloads or slightly uneven surfaces. The bottom of the contact portion 23 protrudes or is at least flush with the bottom end face of the body 10 (i.e., the bottom plane of the first limiting step 11) under natural conditions to ensure reliable contact with the head of the bolt 40. A centering groove 24 is machined at the center of the bottom of the contact portion 23. This groove has a conical or spherical surface that gradually expands outward from the center as a guide surface. When the accessories are installed, regardless of the size of the bolt head (40), its edge will naturally slide into and abut against this guide surface, thereby achieving automatic centering and ensuring consistent detection benchmarks.

[0042] In summary, the accessory of this embodiment directly and amplifies the axial displacement of the bolt 40 into a clear visual signal within the observation window 14 through a highly integrated mechanical structure. Its structure is simple and compact, low in cost, requires no external power supply, and has strong anti-interference capabilities, making it ideal for rapid and intuitive inspection and status monitoring of a large number of bolts 40 in industrial settings.

[0043] The scope of protection of this utility model includes, but is not limited to, the above embodiments. The scope of protection of this utility model is defined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art shall fall within the scope of protection of this utility model.

Claims

1. An accessory for detecting loose bolts, characterized in that, The device includes a body (10) with an internal cavity. The body (10) has a first limiting step (11) and a second limiting step (12). Both the first limiting step (11) and the second limiting step (12) have through holes in the middle. The first limiting step (11) is located at the bottom of the body (10). The second limiting step (12) is located inside the cavity and divides the cavity into a display cavity and a detection cavity from top to bottom. The detection cavity has a baffle (13) and an observation window (14) extending radially along the body (10) on the baffle (13). A detection head (20) is slidably mounted in the detection cavity along the axis. The bottom of the detection head (20) passes through the through hole of the first limiting step (11), and the top passes through the through hole of the second limiting step (12). A detection element (30) made of elastic material is installed on the top of the detection head (20). The detection element (30) is provided with a number of detection pieces (31) corresponding to the observation window (14). The included angle α between the detection piece (31) and the axis of the detection head (20) is greater than 60° and less than 80°. The free end of the detection piece (31) abuts against the inner surface of the baffle (13). When the detection head (20) moves axially, the free end of the detection piece (31) slides along the baffle (13), and the part of it located in the observation window (14) produces a significant radial position change to indicate the displacement.

2. The fitting for detecting loose bolts according to claim 1, characterized in that, The detection head (20) includes a guide portion (21) that is slidably assembled with the body (10), and a contact portion (23) for contacting the head of the bolt (40) to be tested is mounted in the guide portion (21) via a bearing.

3. The fitting for detecting loose bolts according to claim 2, characterized in that, The guide part (21) is provided with a retaining edge (22) on its outer periphery. The retaining edge (22) is provided with a first spring (25) and a second spring (26) on its upper and lower sides along the axial direction of the guide part (21). The upper end of the first spring (25) abuts against the second limiting step (12), and the lower end of the second spring (26) abuts against the first limiting step (11), so that the detection head (20) remains floating in the body (10).

4. The fitting for detecting loose bolts according to claim 3, characterized in that, The bottom of the contact portion (23) protrudes or is flush with the end face of the first limiting step (11) facing the bolt (40) to be tested.

5. The fitting for detecting loose bolts according to claim 2, characterized in that, The bottom of the contact part (23) is provided with a centering groove (24) for guiding the head of the bolt (40) to be aligned. The centering groove (24) has a guide surface that gradually expands from the center outward. During testing, the outer edge of the head of the bolt (40) to be tested abuts against the guide surface to achieve alignment.

6. The fitting for detecting loose bolts according to claim 1, characterized in that, The baffle (13) has a radially extending groove (16) on the side facing the detection piece (30) corresponding to each observation window (14), and the free end of the detection piece (31) is accommodated in the corresponding groove (16).

Images