A breakable and bendable wire rod for use in an airport

Abstract

The utility model relates to mechanical transmission and connection technical field discloses an easy-to-fold and easy-to-break screw rod for airport use, the screw rod includes a screw rod main part, a shearing ring cover is arranged outside the screw rod main part and one precision weakening groove is arranged on the outer wall of the ring cover, there is a preset radial isolation gap between the connecting hole of the screw rod main part and the mounting base, during work, the screw rod main part is only responsible for transmitting movement, all transverse shearing force is borne by the shearing ring cover, and is accurately sheared at the weakening groove when reaching the safety threshold. The utility model completely decouples the transmission function and the shearing function, uses the replaceable ring cover to act as the mechanical fuse with low cost, designs the unique physical mistake prevention structure, realizes the accurate overload protection, greatly reduces the cost, eliminates the misuse risk caused by the missing key parts, and significantly improves the safety and maintainability of the equipment.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission and connection technology, specifically to a lead screw assembly with precise overload shear protection function for use in airport navigation equipment, meteorological facilities, and other applications requiring a flexible structure. Background Technology

[0002] According to the mandatory requirements of the International Civil Aviation Organization (ICAO) and relevant Chinese regulations, certain facilities within the airport's flight zone must be brittle, meaning that their structure can break rapidly in the event of an accidental impact from an aircraft or other aircraft, in order to minimize damage to the aircraft.

[0003] In many easily broken structures that require position adjustment via lead screw drives, the connecting and transmission components face an inherent structural deadlock: on the one hand, as a transmission component, the lead screw needs to have sufficient strength, rigidity, and precision to ensure the stability and reliability of daily operation; on the other hand, as part of an easily broken structure, its connection point must be able to break quickly and predictably when subjected to an accidental lateral impact and reaching a specific shear force threshold.

[0004] Existing technologies typically employ dedicated easily broken lead screws with integrated weakening treatment. This involves machining a weakened section at a specific location on a standard lead screw, making it an easily broken point. This approach suffers from the following three fundamental drawbacks:

[0005] The high cost and supply chain risks are a problem. The special easy-break screw has a complex processing technology and low market demand, resulting in an extremely high purchase price. Its overall cost is significantly higher than the standard parts combination scheme adopted in this utility model. Moreover, the supply cycle is long and unstable, which seriously affects the manufacturing and subsequent maintenance efficiency of the equipment.

[0006] There is a critical safety risk involved. In practice, for convenience or to reduce costs, ordinary high-strength lead screws are easily misused in place of dedicated, easily broken lead screws. Ordinary lead screws, designed to ensure transmission performance, have shear resistance far exceeding safety standards. If misused, they will not break upon impact, potentially escalating a minor collision into a catastrophic accident.

[0007] There is an inherent performance contradiction. Weakening the lead screw itself will inevitably affect its overall transmission stiffness and long-term mechanical accuracy, forming a structural deadlock that cannot be solved by simply optimizing the lead screw itself.

[0008] Therefore, the market urgently needs a new type of safety connector that can perfectly overcome the above-mentioned defects, while achieving high rigidity and high reliability of the structure under normal working conditions and precise and predictable fracture under extreme impact. Utility Model Content

[0009] The purpose of this invention is to provide a low-cost, highly reliable overload shear protection screw assembly with physical error prevention function, aiming to fundamentally solve the contradiction between the screw transmission accuracy and the structural fragility safety requirements in the background technology.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A type of easily broken lead screw for use in airports includes: a lead screw body having a threaded section for transmitting motion and a diameter-adapting section thereon; a hollow shearing ring sleeve coaxially sleeved outside the diameter-adapting section of the lead screw body; and an annular precision weakening groove provided on the outer wall of the shearing ring sleeve.

[0012] Preferably, the lead screw is also used to mate with a mounting base; the mounting base is provided with a connecting hole; the diameter of the connecting hole is larger than the diameter of the rod diameter adaptation section, and the diameter of the connecting hole and the outer diameter of the shearing ring are interference fit or transition fit.

[0013] Preferably, the remaining annular cross-sectional area at the precision weakening groove is calculated and determined based on a preset upper limit threshold of safe shear force and the material shear strength of the shear ring.

[0014] This invention has the following significant advantages over the prior art:

[0015] 1. This utility model completely separates the precision transmission function of the lead screw from the radial shear failure function of the ring by introducing an independent shearing ring. The high-strength lead screw body ensures transmission accuracy and stability, while the low-cost shearing ring acts as a disposable mechanical fuse, accurately meeting the safety requirements for easy breakage.

[0016] 2. The core lead screw body is a general standard part, which is inexpensive. Routine maintenance only requires a small stock of standardized shearing rings. In the event of shearing failure, only the broken ring needs to be replaced, and the lead screw body can be reused immediately, which greatly reduces maintenance costs and equipment downtime.

[0017] 3. The connection structure of this utility model is ingeniously designed. The diameter of the connection hole of the mounting base is much larger than the diameter of the lead screw. Only after the shear ring is correctly installed can an effective surface contact fit be formed to transmit shear force. This physical error-proof structure based on radial isolation gap fundamentally eliminates safety failures caused by the omission of the critical shear ring.

[0018] 4. The precision weakening groove on the shear ring provides a unique stress concentration point for the shear force. Its size can be accurately calculated according to the material mechanics, ensuring the precise control of the fracture location and fracture threshold, and realizing predictable and reliable overload protection. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the assembly structure of one embodiment of the present invention;

[0020] Figure 2 This is an exploded structural diagram of one embodiment of the present invention;

[0021] Figure 3 yes Figure 2 Enlarged structural schematic diagram of the shear ring sleeve;

[0022] Figure 4 This is a schematic diagram of the mechanical principle and force transmission path of this utility model;

[0023] Figure 5 This is a comparative analysis flowchart of the failure logic between this utility model and the prior art.

[0024] In the diagram: 1-Screw body; 2-Shearing ring; 3-Mounting base; 4-Threaded section; 5-Screw diameter fitting section; 6-Precision weakening groove; 7-Connecting hole. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0026] Please see Figures 1 to 3 This utility model provides a screw assembly that is easily broken and fractured for use in airports. The assembly includes a screw body 1, a shearing ring sleeve 2, and is used in conjunction with a mounting base 3.

[0027] The lead screw body 1 is made of 45 steel conforming to GB / T699 standard and heat treated to ensure that it has excellent mechanical strength and transmission accuracy. One end of the lead screw body 1 is machined with a threaded section 4 for transmitting motion, such as a trapezoidal thread of TR2x4 specification, which is used to cooperate with a nut (not shown) to achieve precise linear motion. The other end of the lead screw body 1 is a smooth rod diameter fitting section 5 for installing shearing ring sleeve 2.

[0028] The shear ring sleeve 2 is a hollow circular ring structure, which in this embodiment can be made of 6061-T6 aluminum alloy material with a defined shear strength. It is coaxially fitted onto the outside of the diameter-adapting section 5 of the lead screw body 1 through a central hole. On the outer wall of the shear ring sleeve 2, a V-shaped annular precision weakening groove 6 is machined. The axial position of the weakening groove 6 is precisely set at a position corresponding to the plane of action of the external transverse shear force.

[0029] The mounting base 3 has a connecting hole 7 for mounting the lead screw assembly. In this embodiment, the diameter of the connecting hole 7 is designed to be 25mm. The outer diameter of the shear ring sleeve 2 and the inner wall of the connecting hole 7 form a tight, gapless surface contact through an interference fit, for example, H7 / s6, thereby ensuring that all lateral shear forces acting on the mounting base 3 can be completely and reliably transmitted to the shear ring sleeve 2.

[0030] A key design feature is the dimensional fit between the components. The diameter of the fitting section 5 of the lead screw body 1 is 18mm, which is much smaller than the 25mm diameter of the connecting hole 7. This dimensional difference creates a pre-defined and significant radial isolation gap between the lead screw body 1 and the inner wall of the connecting hole 7 of the mounting base 3. This radial isolation gap constitutes the physical error-proof structure of this invention. If the operator forgets to install the shear ring 2, the lead screw body 1 will experience huge shaking within the connecting hole 7, making it impossible to form any effective connection and force transmission. This physically eliminates the human error of omitting a key safety component.

[0031] Please see Figure 4 The working principle and force transmission path of this utility model are as follows:

[0032] Under normal operating conditions, the lead screw body 1 transmits motion through the rotation of the threaded section 4. When the equipment suffers an unexpected lateral impact, a lateral shear force F is generated. This force is first transmitted from the mounting base 3 to the shear ring sleeve 2 that is in close contact with it. Since there is a radial isolation gap around the lead screw body 1, the force transmission path is decoupled, and the shear force F is completely guided and independently borne by the shear ring sleeve 2.

[0033] Please see Figure 5 The failure logic of this invention stands in stark contrast to the prior art: the integrated weakened lead screw E' of the prior art is responsible for both transmission and shear force bearing, and its functional coupling leads to performance contradictions and poses a dangerous failure risk of the connection exceeding the shear force limit D'. This invention introduces a shear ring sleeve F' to decouple the function of the lead screw body G' to only be responsible for transmission, while the shear ring sleeve F' is dedicated to bearing the shear force, thereby achieving a safe failure mode of precise shearing at a predetermined point.

[0034] In this embodiment, the design of the shear ring 2 follows precise mechanical calculations. For example, in a specific application scenario, if the maximum safe shear force threshold is required to be approximately 28 kN, and the shear strength τ of the selected 6061-T6 aluminum alloy material is approximately 170 MPa, then the remaining annular cross-sectional area at the precision weakening groove 6 must be less than 164.7 mm². This value is specifically calculated by 28000 N ÷ 170 N / mm². In this way, the failure point of the structure can be precisely preset, achieving reliable overload protection.

[0035] Furthermore, the shear ring 2 of this invention is not limited to metal materials: in some cases where there are special requirements for electrical insulation or weight, the shear ring 2 can be made of engineering plastics or composite materials. For example, if a reinforced nylon PA66 material with a shear strength of 80 MPa is selected, in order to achieve the same shear threshold of about 28 kN, the remaining annular cross-sectional area Arem at its precision weakening groove 6 should be designed to be about 350 mm². This ability to apply across material systems further proves the universality and advancement of the functional decoupling design of this invention.

[0036] It is particularly important to emphasize that the final transmission accuracy and long-term working reliability of this utility model depend entirely on the structural rigidity of the lead screw body 1 itself. The function of the shearing ring 2 is only to bear the lateral shear force and act as a one-time mechanical fuse in case of overload. Its own deformation or failure is designed so that it does not affect, and cannot affect, the core transmission performance determined by the lead screw body 1.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A type of easily broken and snapped lead screw used in airports, characterized in that, include: A lead screw body (1) is provided with a threaded section (4) for transmitting motion and a rod diameter matching section (5). A hollow shearing ring sleeve (2) is coaxially sleeved outside the rod diameter adaptation section (5) of the screw body (1); An annular precision weakening groove (6) is provided on the outer wall of the shear ring sleeve (2).

2. The easily broken and snap-fit ​​lead screw used in airports according to claim 1, characterized in that, The lead screw is also used to cooperate with a mounting base (3); the mounting base (3) is provided with a connecting hole (7); the diameter of the connecting hole (7) is larger than the diameter of the rod diameter fitting section (5), and the diameter of the connecting hole (7) and the outer diameter of the shearing ring (2) are interference fit or transition fit.

3. The easily broken and snap-fit ​​lead screw for airport use according to claim 2, characterized in that, There is a difference between the diameter of the connecting hole (7) and the diameter of the rod diameter fitting section (5), thereby forming a preset radial isolation gap between the lead screw body (1) and the connecting hole (7). This radial isolation gap constitutes a physical error prevention structure, so that the lead screw body (1) cannot form an effective force transmission connection with the mounting base (3) without the shear ring sleeve (2) installed.

4. The easily broken and snap-fit ​​lead screw used in airports according to claim 1, characterized in that, Its failure protection mode is limited to: when the transverse shear force exceeds a predetermined value, only the shear ring (2) is sheared at the precision weakening groove (6), while the structure and transmission accuracy of the lead screw body (1) remain intact.

5. The easily broken and snap-fit ​​lead screw for use in airports according to claim 1, characterized in that, The axial position of the precision weakening groove (6) is configured to precisely correspond to the plane of action of the shear force.

6. The easily broken and snap-fit ​​lead screw for use in airports according to claim 1, characterized in that, Its structure is configured such that, during operation, motion is transmitted by the threaded segment (4), while all transverse shear forces are borne entirely by the shearing ring (2).

7. The easily broken and snap-fit ​​lead screw for use in airports according to claim 1, characterized in that, The remaining annular cross-sectional area at the precision weakening groove (6) is calculated based on the preset upper limit threshold of the safe shear force and the material shear strength of the shear ring (2).

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