A harpoon-type torque detection fixture

Abstract

This utility model relates to a harpoon-type torque testing fixture, belonging to the technical field of construction engineering testing tools. This fixture aims to solve the technical problem of effectively testing the torque of mechanical rebar connections in confined spaces between prefabricated components during prefabricated revetment construction using conventional tools. It mainly consists of a handle, a connecting part, and a testing head. Its key feature is the use of hexagonal steel and threaded steel welded into a unique harpoon-shaped structure. The handle is made of hexagonal steel for easy gripping and force application; the testing head is made of threaded steel, its shape matching the sleeve of the joint to be tested; the connecting part has an arc-shaped transition structure, firmly connecting the handle and the testing head. This utility model has a simple and reasonable structure, low manufacturing cost, and convenient and efficient operation. It can complete high-precision torque verification in extremely confined spaces, effectively ensuring the quality of mechanical rebar connections and the safety of the overall structure, possessing outstanding practicality.

Description

Technical Field

[0001] This utility model relates to the technical field of building engineering quality testing tools, and in particular to a harpoon-type torque testing fixture, especially a testing fixture for checking the tightening torque of mechanical connection joints of steel bars in a confined space. Background Technology

[0002] Prefabricated revetment structures, such as double-row pile foundation low-pile cap prefabricated revetments (Type A) and front sheet pile high-pile cap prefabricated revetments (Type D), have been widely used in modern water conservancy and coastal engineering construction. These structures typically use precast reinforced concrete prestressed square piles as foundations, with sleeves pre-installed at the pile tops. Anchoring reinforcement bars are anchored into the pile top sleeves via mechanical connections such as straight thread joints, and then connected to the post-cast strip of the superstructure to form a unified whole. The quality of this connection method directly affects the safety and durability of the entire revetment structure.

[0003] According to the People's Republic of China industry standard "Technical Specification for Mechanical Connection of Reinforcing Bars" (JGJ 107-2016), after the mechanical connection of reinforcing bars is installed, the tightening torque must be checked using a torque wrench to ensure that the joint reaches the specified preload and guarantees the reliability of the connection. This specification clearly requires different tightening torque values ​​for reinforcing bars of different diameters. For example, for reinforcing bars with a diameter not exceeding 16mm, the minimum tightening torque is 100 N·m; for reinforcing bars with a diameter between 18mm and 20mm, it is 200 N·m; for reinforcing bars with a diameter between 22mm and 25mm, it is 260 N·m; for reinforcing bars with a diameter between 28mm and 32mm, it is 320 N·m; for reinforcing bars with a diameter between 36mm and 40mm, it is 460 N·m; and for reinforcing bars with a diameter of 50mm, it is 360 N·m.

[0004] However, in actual construction, especially at the installation joints between precast revetment components and precast reinforced concrete prestressed square piles, the installation space for anchor bars is often extremely narrow (sometimes only 50mm or even less). Conventional torque wrenches, due to their large head size, long handle, and the need for a certain operating radius, simply cannot enter such confined spaces, or even if they can, they cannot perform normal rotational force application, making torque testing impossible to conduct according to specifications. Currently, construction sites often lack effective solutions to this problem, sometimes relying solely on the subjective judgment of construction personnel based on experience, or simply omitting this crucial quality control step altogether. This undoubtedly creates serious safety hazards for the project, potentially leading to serious consequences such as loose joints and structural failure.

[0005] While some torque testing tools or fixtures exist in the prior art, such as portable torque wrenches or dedicated clamping devices disclosed in some patent documents, they are generally not designed for the specific working conditions mentioned above. These existing tools either still have the problem of being too large to adapt to extremely confined spaces; or they have complex structures, high manufacturing costs, are unsuitable for the harsh environment of construction sites, and are difficult to popularize; or their testing principles and structures determine their insufficient stability and accuracy in confined spaces. For example, a patent document with authorization publication number CN218639422U discloses a torque testing clamping fixture, which includes a fixture base plate, a handrail frame, a telescopic motor, and a complex clamping device. The overall structure is bulky, requires an external power source, and is obviously not applicable to the confined spaces between prefabricated components. Moreover, it is costly and inconvenient to operate.

[0006] Therefore, those skilled in the art urgently need to develop a torque testing fixture that is compact, simple, reliable, low-cost, and specifically designed for confined spaces, in order to solve the aforementioned long-standing technical problems, meet regulatory requirements, and ensure engineering quality. Utility Model Content

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a harpoon-type torque testing fixture. This fixture effectively solves the problem of verifying the tightening torque of mechanical connection joints of reinforcing bars within the confined spaces of structures such as prefabricated revetments. This utility model fixture should possess the characteristics of simple structure, low manufacturing cost, convenient operation, strong adaptability, and accurate and reliable testing results.

[0008] The above-mentioned utility model objective is achieved through the following technical solution: This utility model provides a harpoon-type torque detection fixture, including a handle, a connecting part, and a detection head. The handle is made of hexagonal steel, and the detection head is made of threaded steel. The handle is welded to the detection head through the connecting part to form a harpoon-type structure.

[0009] According to one embodiment of the present invention, the hexagonal steel of the handle portion has a side dimension of 10mm to 20mm and a length range of 200mm to 400mm.

[0010] According to one embodiment of the present invention, the diameter of the threaded steel of the detection head is adapted to the inner diameter of the sleeve of the mechanical connection joint of the reinforcing bar, and the diameter range is 16mm to 40mm.

[0011] According to one embodiment of the present invention, the connecting part is an arc-shaped transition structure, which is welded from the same or compatible metal material as the handle part and the detection head, and the bending radius ranges from 50mm to 150mm.

[0012] According to one embodiment of the present invention, the harpoon-shaped structure is specifically Y-shaped, and the detection head is forked to form two legs.

[0013] According to one embodiment of the present invention, the end of the support leg is processed with anti-slip texture, which is any one of mesh, stripe or dot-like protrusions.

[0014] According to one embodiment of the present invention, the welding between the handle part, the connecting part and the detection head is completed by arc welding or gas shielded welding process, and the strength of the weld is not lower than the strength of the base material.

[0015] According to one embodiment of the present invention, a torque calibration module is also included, which is integrated on the handle and is used to detect and display the applied torque value in real time.

[0016] According to one embodiment of the present invention, the torque calibration module includes a sensor unit and a display unit, wherein the sensor unit is a strain gauge sensor or a piezoelectric sensor.

[0017] According to one embodiment of the present invention, the outer surface of the tooling is coated with an anti-corrosion coating, which is an epoxy resin coating or a zinc-based coating.

[0018] In summary, compared with the prior art, the present invention has at least one of the following beneficial technical effects: Excellent spatial adaptability: The unique harpoon-shaped (Y-shaped) structural design makes the inspection head very compact, allowing it to easily enter narrow spaces that conventional wrenches cannot reach, fundamentally solving the inspection problems under specific working conditions.

[0019] Simple structure and low cost: The entire tooling is mainly made of common hexagonal steel and threaded steel through welding. The structure is extremely simple, the raw materials are readily available, the processing technology is simple, the manufacturing cost is very low, and it is easy to mass-produce and widely apply on construction sites.

[0020] Easy to operate and highly efficient: The operator only needs to insert the detection head into the connector sleeve and apply force by holding the handle to complete the detection. The operation process is simple and intuitive, requiring no complicated training, and can significantly improve the efficiency of detection work.

[0021] Reliable and accurate detection: Based on the lever principle, torque transmission is direct and effective. Combined with anti-slip textures and a stable Y-shaped support structure, slippage and deflection are effectively avoided, ensuring the reliability and accuracy of torque detection. With the addition of a torque calibration module, quantitative detection can be achieved, resulting in even higher accuracy.

[0022] Robust and durable: Constructed from welded metal materials, its robust structure and high strength allow it to withstand harsh conditions at construction sites. Surface anti-corrosion treatment further enhances its durability.

[0023] The core technological advantage of this harpoon-shaped torque testing fixture lies in its innovative solution to the long-standing industry challenge of effectively detecting the torque of mechanically connected rebar joints in confined spaces during prefabricated revetment construction. Through a unique harpoon-shaped structure welded from hexagonal steel and threaded steel, the fixture achieves excellent spatial adaptability. Its compact testing head can easily reach into narrow gaps inaccessible to conventional torque wrenches (such as the anchor bar installation space between prefabricated revetments and prestressed square piles), thus enabling direct, in-situ verification of the tightening torque of straight threaded joints and ensuring that the project quality meets the mandatory requirements of the "Technical Specification for Mechanical Connection of Rebar".

[0024] In terms of structural design and performance, this tooling exhibits outstanding simplicity and reliability. Its simple structure and high rigidity, constructed solely from common steel welded together, make it inexpensive to manufacture and durable, ideal for harsh construction environments. The hexagonal steel handle provides a non-slip, effortless grip, while the threaded steel detection head effectively engages with the connector sleeve. This lever-based design allows operators to easily apply and transmit torque, effectively avoiding issues of decreased detection accuracy or inability to detect due to space constraints, ensuring accurate and reliable test results.

[0025] In summary, this tooling has demonstrated significant practical value. It successfully transforms the complex task of torque testing into a simple and efficient operation, requiring no complex equipment or additional power source and can be completed by a single person, greatly improving testing efficiency. Its successful application ensures the quality of mechanical connections of reinforcing bars, fundamentally eliminating potential structural safety hazards caused by unqualified torque. It is of great value in ensuring the overall safety and durability of structures such as double-row pile foundation low-pile cap prefabricated revetments (Type A) and front sheet pile high-pile cap prefabricated revetments (Type D), and shows promising prospects for widespread application in the civil engineering field. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0027] Reference numerals: 1. Handle; 2. Connecting part; 3. Detection head; 31. Support foot; 311. Anti-slip texture; 4. Torque calibration module; 41. Sensor unit; 42. Display unit; 5. Anti-corrosion coating. Detailed Implementation

[0028] The technical solutions in 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 embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0029] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] Example 1: Reference Figure 1 This utility model discloses a harpoon-type torque testing fixture, comprising a handle 1, a connecting part 2, and a testing head 3. The handle 1 is made of hexagonal steel, and the testing head 3 is made of threaded steel. The handle 1 and the testing head 3 are welded together via the connecting part 2 to form a harpoon-type structure. The handle 1, made of a section of hexagonal steel, utilizes the hexagonal edges to facilitate gripping and torque application by the operator, preventing slippage. The testing head 3, made of threaded steel, is machined to match the inner wall or outer edge of the sleeve of the mechanical connection joint of the reinforcing bar to be tested, thereby achieving effective engagement. The connecting part 2 is a transition structure, preferably with an arc design, which firmly connects the handle 1 and the testing head 3 together, forming a unique harpoon-type (or Y-shaped) integral structure.

[0032] The harpoon-shaped structure is its core innovation. This design minimizes the lateral dimension (width) of the detection head 3, allowing it to easily penetrate extremely narrow gaps between prefabricated components. Simultaneously, the Y-shaped structure provides better stability under stress, preventing tipping or slippage during torque application. The handle 1 acts as a lever arm; by applying force to the handle 1, the operator uses leverage to transmit amplified torque to the detection head 3, which then acts on the sleeve of the connector to complete torque verification.

[0033] The hexagonal steel of the handle 1 has a side dimension of 10mm to 20mm and a length range of 200mm to 400mm. This size range balances ease of operation, effectiveness of force application, and overall compactness of the tooling. The threaded steel diameter of the inspection head 3 is adapted to the inner diameter of the sleeve of the rebar mechanical connection joint, with a diameter range of 16mm to 40mm to cover rebar mechanical connection joints of common diameters. The harpoon-type structure is specifically Y-shaped, with the inspection head 3 forked to form two legs 31.

[0034] The connecting part 2 has an arc-shaped transition structure, which is welded from the same or compatible metal material as the handle part 1 and the detection head 3, with a bending radius ranging from 50mm to 150mm. This arc-shaped design facilitates smooth force transmission, reduces stress concentration, and improves the structural strength and durability of the tooling. The end of the support leg 31 is machined with anti-slip texture 311, which can be any of the following: mesh, stripe, or dotted raised patterns, to significantly increase the friction between the support leg and the sleeve, prevent slippage, and ensure effective torque transmission. The welding between the handle part 1, the connecting part 2, and the detection head 3 is completed using arc welding or gas shielded welding. The strength of the weld is not lower than the strength of the base material, ensuring the integrity and reliability of the tooling.

[0035] In this embodiment, a torque calibration module 4 is also included. The torque calibration module 4 is integrated on the handle part 1 and is used to detect and display the applied torque value in real time. The torque calibration module 4 includes a sensor unit 41 and a display unit 42. The sensor unit 41 is a strain gauge sensor or a piezoelectric sensor, and the display unit 42 is a liquid crystal display screen. It can detect and digitally display the applied torque value in real time, making the detection results more intuitive and accurate.

[0036] The outer surface of the tooling is coated with an anti-corrosion coating 5, which is an epoxy resin coating or a zinc-based coating. Considering that the tooling may be used in a humid and corrosive civil engineering environment for a long time, an anti-corrosion coating 5, such as an epoxy resin coating or a zinc-based coating, can be applied to its outer surface to extend its service life.

[0037] This embodiment provides a basic harpoon-type torque detection fixture. The fixture consists of a handle part 1, a connecting part 2, and a detection head 3, which are welded together to form a complete harpoon-type structure.

[0038] The handle 1 is made of a section of Q235 hexagonal steel with a face dimension of 15mm and a length of 300mm. The six planes of the hexagonal steel provide a good grip and facilitate the application of force. The detection head 3 is made of two sections of HRB400 threaded steel with a nominal diameter of 22mm, suitable for mechanical connection joints for detecting rebar with a diameter of 22mm to 25mm. One end of these two sections of threaded steel is welded to the connecting part 2, forming the fork of the harpoon. The end of the support leg 31 is machined with striped anti-slip texture 311 using an angle grinder to enhance the engagement with the inner wall of the sleeve. The connecting part 2 is made of the same hexagonal steel as the handle 1, heated and bent to form a smooth arc transition with a bending radius of approximately 100mm. It connects the non-fork end of the handle 1 and the detection head 3. During manufacturing, the materials are first cut, then the parts are positioned in the fixture and welded using an arc welding process to ensure that the weld is full, continuous, and that the weld strength is not lower than that of the base material. After welding, the weld spatter is ground to make the appearance smooth. Finally, the entire tooling is sandblasted to remove rust and coated with a layer of gray epoxy resin anti-corrosion coating 5, with a coating thickness of approximately 50μm.

[0039] The torque calibration module 4 enables real-time digital display of torque. The torque calibration module 4 is integrated into the handle section 1. Its sensor unit 41 uses a high-precision resistance strain gauge, which is attached to the force-sensitive area of ​​the handle section 1 near the connecting part 2 (this area was optimized through finite element analysis) to sense the minute deformation of the handle section 1 under force. The display unit 42 is a small liquid crystal display (LCD), embedded in the middle of the handle section 1. The deformation signal (resistance change) detected by the sensor unit 41 is amplified and filtered by the signal conditioning circuit, then converted into a torque value by the microprocessor unit (MCU) based on the preset lever arm length, and finally displayed in real-time on the display unit 42. This module is powered by a built-in button battery. During use, the operator can apply force while directly reading the torque value on the display screen, and stop applying force when the value reaches the specified requirement. This method makes the detection results more accurate and objective, avoids errors in human judgment, and achieves quantitative detection.

[0040] Instructions for use: When it is necessary to test the torque of the mechanical connection joint of the anchor bars between precast revetment components and precast reinforced concrete prestressed square piles, conventional wrenches cannot be accessed due to limited space. The operator aligns the testing head 3 (leg 31) of this tool with the corresponding slot of the joint sleeve or directly clamps it onto the outer edge of the sleeve, then holds the handle 1 and applies force steadily in the direction of torque (clockwise or counterclockwise). According to the lever principle (torque = force × lever arm length), if a force of approximately 87N (approximately equivalent to 8.7 kgf) is applied to the end of the handle 1, with a lever arm length of 0.3 meters, a torque of approximately 26.1 N·m can be generated. By observing whether the joint rotates, it can be determined whether the torque meets the requirements (for example, for a 22mm diameter rebar, the minimum tightening torque is 260 N·m, requiring a force of approximately 867N). This utility model tool has a compact structure and can easily reach into confined spaces to complete the testing task.

[0041] The implementation principle of this utility model is as follows: This utility model discloses a harpoon-type torque detection fixture, belonging to the technical field of construction engineering testing tools. This fixture aims to solve the technical problem that the torque of mechanical connection joints of reinforcing bars in the confined space between prefabricated components during prefabricated revetment construction cannot be effectively detected using conventional tools. It mainly consists of a handle part 1, a connecting part 2, and a detection head 3. Its key feature is the use of hexagonal steel and threaded steel welded into a unique harpoon-shaped structure. The handle part 1 is made of hexagonal steel for easy gripping and force application; the detection head 3 is made of threaded steel, and its shape matches the sleeve of the joint to be tested; the connecting part 2 is an arc-shaped transition structure that securely connects the handle part 1 and the detection head 3. This utility model has a simple and reasonable structure, low manufacturing cost, and convenient and efficient operation. It can complete high-precision torque verification work in extremely confined spaces, effectively ensuring the quality of mechanical connections of reinforcing bars and the safety of the overall structure, and possesses outstanding practicality.

[0042] The embodiments described herein are preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape, and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A harpoon-type torque detection fixture, characterized in that: It includes a handle (1), a connecting part (2) and a detection head (3). The handle (1) is made of hexagonal steel and the detection head (3) is made of threaded steel. The handle (1) is welded to the detection head (3) through the connecting part (2) to form a harpoon-shaped structure.

2. The harpoon-type torque detection fixture according to claim 1, characterized in that: The hexagonal steel of the handle part (1) has a side dimension of 10mm to 20mm and a length range of 200mm to 400mm.

3. The harpoon-type torque detection fixture according to claim 1, characterized in that: The diameter of the threaded steel of the detection head (3) is adapted to the inner diameter of the sleeve of the mechanical connection joint of the reinforcing bar, and the diameter range is 16mm to 40mm.

4. The harpoon-type torque detection fixture according to claim 1, characterized in that: The connecting part (2) is an arc-shaped transition structure, which is welded from the same or compatible metal material as the handle part (1) and the detection head (3), with a bending radius ranging from 50 mm to 150 mm.

5. The harpoon-type torque detection fixture according to claim 1, characterized in that: The harpoon-shaped structure is specifically Y-shaped, and the detection head (3) branches to form two legs (31).

6. The harpoon-type torque detection fixture according to claim 5, characterized in that: The end of the support leg (31) is processed with anti-slip texture (311), which can be any one of mesh, stripe or dot protrusion.

7. The harpoon-type torque detection fixture according to claim 1, characterized in that: The welding between the handle part (1), the connecting part (2) and the detection head (3) is completed by arc welding or gas shielded welding process, and the strength of the weld is not lower than the strength of the base material.

8. A harpoon-type torque detection fixture according to any one of claims 1 to 7, characterized in that: It also includes a torque calibration module (4), which is integrated on the handle (1) and is used to detect and display the applied torque value in real time.

9. A harpoon-type torque detection fixture according to claim 8, characterized in that: The torque calibration module (4) includes a sensor unit (41) and a display unit (42), wherein the sensor unit (41) is a strain gauge sensor or a piezoelectric sensor.

10. A harpoon-type torque detection fixture according to claim 1, characterized in that: The outer surface of the tooling is coated with an anti-corrosion coating (5), which is an epoxy resin coating or a zinc-based coating.

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