screw

Abstract

The application relates to a bolt, which comprises a head and a screw rod and further comprises: a blind hole, the inner end of the blind hole being arranged in the screw rod, and the outer end of the blind hole penetrating through the head; a jack rod, which is arranged in the blind hole and is fixedly connected with the blind end of the blind hole at the lower end; and a sensing device, which is arranged on the head and is used for converting the axial displacement of the upper end of the jack rod into an electric signal. The intelligent bolt of the application can realize instant feedback of the loosening state of the bolt by real-time detection of the axial displacement of the jack rod representing the deformation of the bolt, conversion of the mechanical displacement into the electric signal, compact structure, seamless integration of the sensing device and the bolt body through the embedded design of the blind hole and the jack rod, reservation of the traditional bolt appearance, no need to greatly change the traditional bolt structure, easy installation, real-time monitoring of the bolt state, reduction of the artificial inspection frequency, reduction of the maintenance cost, remote monitoring through wireless signals, and improvement of the safety management efficiency.

Description

Technical Field

[0001] This application relates to the field of mechanical fasteners, and more particularly to a bolt capable of real-time monitoring of its loosening status. Background Technology

[0002] In the industrial sector, bolts are widely used as critical fasteners to connect structural components such as beams, girders, discs, bearings, flanges, valves, and plates. Their reliability directly affects the integrity of the equipment. Traditional bolt assemblies typically include a bolt head, a bolt shank, a washer, and a threaded nut, which provides the connection force through tightening.

[0003] Loose bolts in some critical components can lead to equipment malfunctions or even safety accidents. To ensure the rigidity and mechanical integrity of the structure, bolts and other fasteners must be inspected regularly. Factors that cause fastener failure during use mainly include: vibration, which may cause bolts to loosen; environmental exposure, which can lead to corrosion and material deterioration; stress, which can cause fatigue fracture or shear failure; and strain, which can cause bolt elongation, cracking, or even complete failure.

[0004] However, current bolt maintenance faces two major challenges. First, manual inspection is inefficient and prone to delays, requiring periodic shutdowns for visual inspection, torque testing, or non-destructive testing to verify bolt condition. Manual inspection is labor-intensive, often requiring specialized personnel to work at heights or in hazardous conditions, posing safety risks. Furthermore, the inspection intervals cannot detect sudden loosening, such as nut displacement caused by vibration. In addition, equipment downtime leads to production delays and high costs.

[0005] Secondly, existing monitoring technologies are inadequate, often being complex in structure, costly, and unreliable. For example, contact sensor solutions require external circuitry, which compromises the strength of the bolt structure and is complex to install; optical detection solutions rely on external light sources and image processing, and fail in environments such as oil stains and high temperatures.

[0006] In summary, existing technologies struggle to balance structural compactness, reliability, real-time performance, and adaptability to harsh environments. For instance, the micron-level deformation of bolts in vibration scenarios cannot be captured by conventional sensors, while high-precision deformation detection devices are often bulky.

[0007] Therefore, there is an urgent need for a smart bolt solution that can achieve remote, real-time, and highly reliable monitoring of the fastening status without interrupting equipment operation. Utility Model Content

[0008] To at least partially address one or more of the technical problems mentioned in the background art, this application provides a bolt. The bolt of this application integrates a sensing device, enabling real-time detection of the bolt's tightness and feedback of any abnormalities via electrical signals.

[0009] This application provides a bolt, including a head and a screw, characterized in that it further includes: a blind hole, the inner end of which is disposed in the screw, and the outer end of which penetrates through the head; a push rod, disposed in the blind hole, the lower end of which is fixedly connected to the blind end of the blind hole; and a sensing device disposed on the head for converting the axial displacement of the upper end of the push rod into an electrical signal.

[0010] In some embodiments, the sensing device is a micro switch.

[0011] In some embodiments, when the bolt is tightened, the micro switch is a certain distance away from the upper end of the push rod, and the micro switch is de-energized. When the bolt is loosened, the upper end of the push rod contacts the micro switch, and the micro switch is energized.

[0012] In some embodiments, a micro switch is connected to a light-emitting device, and when the micro switch is energized, the light-emitting device operates to indicate an abnormality.

[0013] In some embodiments, a micro switch is connected to an alarm device, and when the micro switch is energized, the alarm device operates to issue an abnormal indication.

[0014] In some embodiments, the axis of the push rod coincides with the axis of the blind hole.

[0015] In some embodiments, the bolt further includes a wireless signal transmitting module for wirelessly transmitting electrical signals from the sensing device.

[0016] In some embodiments, the bolt further includes: a housing, secured to the head, for mounting the sensing device.

[0017] In some embodiments, the bolt further includes a battery for powering the sensing device.

[0018] In some embodiments, the bolt further includes a circuit board for processing electrical signals from the sensing device.

[0019] This application provides a smart bolt with an integrated sensing device. By detecting the axial displacement of the push rod, which characterizes bolt deformation, in real time, the mechanical displacement is converted into an electrical signal, thereby achieving instant feedback on the bolt's loosening status. The smart bolt of this application has a compact structure. Through the embedded design of the blind hole and push rod, the sensing device is seamlessly integrated with the bolt body, retaining the traditional bolt shape without significantly altering the traditional bolt structure, making it easy to install. It can monitor the bolt status in real time, reducing the frequency of manual inspections and lowering maintenance costs. It can also achieve remote monitoring via wireless signals, improving safety management efficiency. Attached Figure Description

[0020] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0021] Figure 1 A perspective view of a bolt according to an embodiment of this application is shown;

[0022] Figure 2 A schematic diagram of the bolt structure according to an embodiment of this application is shown;

[0023] Figure 3 An exploded view of a bolt according to an embodiment of this application is shown.

[0024] Reference numerals: 1 Head; 2 Screw; 3 Blind hole; 4 Top rod; 5 Sensing device; 11 Bolt body; 12 Housing; 13 Top rod; 14 Micro switch retaining ring; 15 Micro switch; 16 Device retaining shell; 17 Circuit board; 18 Top cover. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be understood that the terms "first," "second," "third," and "fourth," etc., used in the claims, specification, and drawings of this application are used to distinguish different objects, rather than to describe a specific order. The terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0027] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0028] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0029] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0030] like Figure 1 and Figure 2 As shown, the bolt of this application includes a head 1, a screw 2, a blind hole 3, a push rod 4, and a sensing device 5. The inner end of the blind hole 3 is disposed within the screw 2, and the outer end of the blind hole 3 penetrates through the head 1. The push rod 4 is disposed within the blind hole 3, and the lower end of the push rod 4 is fixedly connected to the blind end of the blind hole 3. The sensing device 5 is disposed on the head 1 and is used to convert the axial displacement of the upper end of the push rod 4 into an electrical signal. Those skilled in the art will understand that the orientation of the upper and lower ends referred to here is not an absolute orientation relative to the Earth's center, but rather a descriptive orientation based on the relative orientation of the head above the screw / the screw below the head for ease of description.

[0031] Generally, the blind hole 3 is located at the center axis of the bolt, but it may also be an eccentric hole (for special bolt layouts or to avoid stress zones). The axis of the push rod 4 coincides with the axis of the blind hole 3. The axial deformation of the bolt or screw 2 can correspond to the blind end of the blind hole 3 according to a preset ratio. The deeper the blind hole, the higher the corresponding ratio. However, considering both monitoring accuracy requirements and cost control needs, the depth of the blind hole can be set to 20% to 80% of the screw length. In extreme cases, the blind hole may not be a blind hole but a through hole, that is, the lower end of the push rod 4 is flush with and fixedly connected to the bottom end of the screw 2. The lower end of the push rod 4 is fixedly connected to the blind end of the blind hole 3, and other parts of the push rod 4 do not contact or have low friction contact with the inner wall of the blind hole 3. This allows the displacement of the blind end of the blind hole 3 to be directly converted into the displacement of the upper end of the push rod 4 through the push rod 4, that is, the deformation of the screw 2 is transmitted upward to the head 1 area for sensing and measurement. In addition, the lower end of the push rod 4 is fixedly connected to the blind end of the blind hole 3, which can prevent the lower end of the push rod 4 from deviating from the blind end of the blind hole 3 due to mechanical vibration or centrifugal force during equipment operation, thus affecting the reliability of monitoring. Furthermore, it eliminates the need for on-site adjustment of the position of the push rod 4 when installing the bolts.

[0032] Traditional bolts are generally made of metal / alloy materials, and the push rod 4 is also preferably made of metal / alloy materials, but it is not required to be the same material as the bolt. As long as it has sufficient rigidity and can be used in the working environment of the bolt, it is acceptable. The push rod 4 can also be made of ceramic, glass, composite materials, etc.

[0033] Optionally, the sensing device 5 is a micro switch. When the bolt is tightened, the micro switch is a certain distance away from the upper end of the push rod 4, and the micro switch is de-energized; when the bolt is loosened, the upper end of the push rod 4 contacts the micro switch, and the micro switch is energized. Preferably, the micro switch is connected to a light-emitting device and / or an alarm device. When the micro switch is energized, the light-emitting device and / or the alarm device operate to issue an abnormal indication.

[0034] Optionally, the bolt also includes a wireless signal transmitting module for wirelessly transmitting the electrical signals of the sensing device 5. The wireless signal transmitting module is compatible with Bluetooth, Wi-Fi, Zigbee, LoRa, Sigfox, NB-IoT, UWB, or 5G protocols to meet the transmission needs of different scenarios.

[0035] Optionally, the bolt also includes a housing, which is fixed to the head 1 for mounting the sensing device 5.

[0036] Optionally, the bolt also includes a battery for powering the sensing device 5.

[0037] Optionally, the bolt also includes a circuit board for processing electrical signals from the sensing device 5.

[0038] like Figure 3 As shown, the bolt mainly includes a bolt body 11, a push rod 13, a micro switch 15, and necessary auxiliary components. The bolt body 11 has a conventional head and a threaded portion. A blind hole is machined axially inside the threaded portion, with its inner end terminating inside the threaded portion and its outer end completely penetrating the bolt head, forming an opening on the top surface of the head. The push rod 13 is securely mounted within the blind hole. The lower end of the push rod 13 (i.e., the end closest to the blind end of the blind hole) is fixedly connected to the blind end of the blind hole by means such as interference fit, threaded connection, bonding, or welding. Therefore, the push rod 13 can accurately follow the axial movement of the bolt threaded portion under axial tension (elongation) or retraction (shortening) when loosened.

[0039] The housing 12 is securely mounted to the free end region of the bolt head via interference fit, threaded connection, snap-fit, bonding, or welding. It is important to emphasize that the housing 12 is installed in the area where the bolt head undergoes minimal deformation under working tensile force (the free end), generally referring to the outer edge of the bolt head, where deformation is negligible. Inside the housing 12, a device mounting shell 16 is provided. The micro switch 15 is mounted within the device mounting shell 16. To ensure the micro switch 15 is fixed in place, a micro switch retaining ring 14 is used, which secures the micro switch 15 tightly inside the device mounting shell 16 via interference fit, threaded connection, bonding, or welding. The contacts of the micro switch 15 (typically normally open contacts) face the blind hole direction. The battery and a circuit board 17 containing signal processing circuitry and a wireless signal transmission module (such as a Bluetooth Low Energy module) are also mounted within the device mounting shell 16. The circuit board 17 typically integrates a light-emitting device (such as an LED) or a sound alarm (such as a buzzer). The micro switch 15, battery and circuit board 17, and light-emitting device / sound alarm are electrically connected via wires or printed circuits to form a complete circuit loop. This circuit system is entirely powered by the built-in battery and requires no external power cable.

[0040] During assembly, a key step is to install the entire assembly, including the microswitch 15, microswitch retaining ring 14, device housing 16, battery, and circuit board 17, into the housing 12, which is already secured to the bolt head. When installing this assembly, its position needs careful adjustment so that, in the initial state (i.e., when the bolt is not tightened), the upper end of the push rod 13 (the end closest to the bolt head opening) can reliably contact the contacts of the microswitch 15. This can be aided by observing the light-emitting device on the circuit board 17 (usually requiring a transparent cover 18 for observation later, or the cover 18 can be left uncovered temporarily): when the light-emitting device is stably lit, it indicates that the push rod 13 has made good contact with and triggered the contacts of the microswitch 15, and the assembly position is correct. Finally, the transparent cover 18 (e.g., made of polycarbonate) is encapsulated on top of the housing 12, protecting the internal components and allowing personnel to clearly observe the working status of the internal light-emitting device. Those skilled in the art will understand that the technical solution of this application involves assembling the bolts before they leave the factory. That is, the bolts are assembled before leaving the factory and no working load is applied (i.e., the bolt is in its natural length state), meaning they are not tightened and have no deformation. Only when the bolts are installed on the equipment and tightened after leaving the factory will they bear the normal working load and elongate.

[0041] The working principle of this smart bolt is as follows: When the bolt is properly tightened and bears a working load, the bolt shank will undergo elastic elongation due to axial tension. Since the lower end of the push rod 13 is fixed to the blind end of the blind hole that elongates along with the bolt shank, the push rod 13 will also undergo downward axial displacement (away from the bolt head). Simultaneously, the micro switch 15 is securely mounted in the free end region of the bolt head, where it does not deform, via the device fixing housing 16, the micro switch fixing ring 14, and the housing 12, and its position is relatively fixed. Therefore, when the bolt is elongated, the upper end of the push rod 13 moves downward, separating from the contact of the micro switch 15. The upper end of the push rod 13 is separated from the contact of the micro switch 15 by a certain distance, for example, between 0.1 and 10 mm, causing the micro switch 15 to disconnect (power-off state). At this time, the entire circuit is disconnected, the light-emitting device is off, and the wireless transmission module does not work. Importantly, in this normal operating state, the circuit is in an open state and does not consume any electrical energy. When a bolt loosens (preload decreases) or even breaks, the axial tension acting on the bolt decreases or disappears, and the bolt's elastic elongation recovers, causing its length to retract. At this time, the push rod 13 fixed to the bottom of the blind hole also retracts upwards and resets. When the upper end of the push rod 13 moves upwards and re-contacts the contact of the micro switch 15, the micro switch 15 is triggered and closed (energized state). The circuit is completed, the light-emitting device is lit, emitting a visible light alarm signal (observable through the transparent top cover 18), or a buzzer alarm. Simultaneously, the wireless signal transmission module on the circuit board 17 is activated, wirelessly transmitting an abnormal signal (electrical signal) representing bolt loosening or failure. This signal can be received and processed by nearby receiving devices (such as handheld terminals or receivers) to achieve remote alarm.

[0042] Therefore, in this embodiment, the axial deformation of the bolt is converted into the on / off action of the microswitch 15 by the push rod 13, realizing the monitoring of the bolt status. In case of abnormality, an alarm is issued through local light / buzzer and / or wireless signals. Furthermore, the circuit is disconnected during normal bolt operation, achieving zero-power standby and greatly extending the lifespan of the built-in battery. To prevent battery drain after bolt assembly and before installation into the equipment, a disposable battery insulating sheet can be provided, which is removed after installation.

[0043] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A bolt, comprising a head and a shank, characterized in that, Also includes: A blind hole, the inner end of which is disposed inside the screw, and the outer end of which penetrates the head; A push rod is disposed within the blind hole, and the lower end of the push rod is fixedly connected to the blind end of the blind hole; A sensing device, disposed on the head, is used to convert the axial displacement of the upper end of the push rod into an electrical signal.

2. The bolt according to claim 1, characterized in that, The sensing device is a micro switch.

3. The bolt according to claim 2, characterized in that, When the bolt is tightened, the micro switch is a certain distance away from the upper end of the push rod, and the micro switch is de-energized; when the bolt is loosened, the upper end of the push rod contacts the micro switch, and the micro switch is energized.

4. The bolt according to claim 2, characterized in that, The micro switch is connected to a light-emitting device. When the micro switch is energized, the light-emitting device operates to issue an abnormal indication.

5. The bolt according to claim 2, characterized in that, The micro switch is connected to an alarm device. When the micro switch is energized, the alarm device operates to issue an abnormal indication.

6. The bolt according to any one of claims 1 to 5, characterized in that, The axis of the top rod coincides with the axis of the blind hole.

7. The bolt according to any one of claims 1 to 5, characterized in that, Also includes: A wireless signal transmitting module is used to wirelessly transmit the electrical signals of the sensing device.

8. The bolt according to any one of claims 1 to 5, characterized in that, Also includes: A housing, fixed to the head, is used to mount the sensing device.

9. The bolt according to any one of claims 1 to 5, characterized in that, Also includes: A battery is used to power the sensing device.

10. The bolt according to any one of claims 1 to 5, characterized in that, Also includes: A circuit board for processing the electrical signals of the sensing device.

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