A dovetail joint device for emergency aluminium alloy truss bridge chord

Abstract

This invention discloses a dovetail joint connection device for emergency aluminum alloy truss bridge chords, comprising two chords. A first connector and a second connector are respectively provided at opposite ends of the two chords. The first and second connectors are connected to the two chords via multiple shafts. The first connector has a dovetail mortise facing the second connector, and the second connector has a dovetail tenon aligned with the dovetail mortise, which is inserted into the inside of the dovetail mortise. A first limiting hole is provided at the first connector aligned with the dovetail mortise, and a second limiting hole is provided at the dovetail tenon aligned with the first limiting hole. A trapezoidal locking element is inserted after the first and second limiting holes are aligned. This invention eliminates the need for torque wrenches, power tools, or other specialized equipment; assembly can be completed manually. Blind assembly and alignment can be performed in low-light conditions at night.

Description

Technical Field

[0001] This invention relates to the field of temporary prefabricated bridge structures, specifically a dovetail joint connection device for the chords of emergency aluminum alloy truss bridges. Background Technology

[0002] Emergency aluminum alloy truss bridges, with their advantages of light weight, convenient transportation, rapid erection, and reusability, are widely used in engineering scenarios with extremely high time requirements, such as road collapse repair, flood control across rivers, temporary passage at major accident sites, and emergency support channels in the field. As the core load-bearing components of the entire bridge, the connection nodes between adjacent trusses directly determine the overall erection efficiency, load-bearing stiffness, fatigue service life, and component reusability of the bridge, making them a core and critical part of emergency truss bridge design. Currently, the common connection methods for emergency aluminum alloy truss chords in the industry are bolted connections and pin connections. Both have inherent defects that make them difficult to adapt to extreme emergency conditions, and cannot simultaneously meet the five core requirements of rapid assembly, long-term reliability, non-destructive disassembly, multiple reuses, and all-weather environmental adaptability.

[0003] Traditional bolted connections place stringent requirements on the precision of prefabricated component hole machining and on-site alignment. In emergency situations, conditions such as mud, darkness, and slight component deformation can easily lead to thread misalignment. Bolt installation is extremely time-consuming, resulting in lengthy assembly times for single nodes, failing to meet the minute-level emergency response requirements. Under the combined effects of vehicle reciprocating loads, temperature cycles, and wind vibration, bolt preload continuously decreases, threads gradually loosen, and node stiffness deteriorates, necessitating significant manpower for regular inspection and re-tightening. Opening holes in aluminum alloy members weakens the cross-sectional load-bearing capacity, and long-term pressure on the hole walls can easily cause extrusion deformation and tearing damage. During the end-of-service dismantling phase, long-term moisture and corrosion of the threads, along with heavy-load plastic deformation, can easily cause thread seizure and adhesion. Most nodes can only be dismantled using destructive methods such as cutting and hammering, significantly reducing the number of times aluminum alloy chords can be reused, and resulting in high costs for emergency supplies and maintenance.

[0004] While pin connections eliminate the need for bolt tightening, a clearance must be maintained between the pin and the pin hole for proper assembly. When heavy rescue vehicles pass through frequently, generating continuous vibrations, the pin repeatedly impacts the hole wall, causing severe fretting wear and rapid attenuation of joint stiffness, failing to meet medium- to long-term emergency traffic control requirements. Pins rely solely on shear force transmission, exhibiting significant weaknesses under combined tensile, compressive, and bending loads. Overload conditions easily lead to plastic bending of the pin and elliptical deformation of the pin hole. Furthermore, anti-disengagement relies only on small, easily damaged components such as cotter pins and retaining rings, which are prone to detachment and instability under vibration. After repeated disassembly and reassembly, the pin hole undergoes irreversible deformation, resulting in extremely low component reuse rates. In water-filled or high-salt coastal environments, pins rapidly corrode and jam, significantly increasing the difficulty of disassembly.

[0005] In summary, the existing two types of connection structures have shortcomings in assembly efficiency, mechanical reliability, disassembly and reuse performance, environmental adaptability, and fatigue life. Aluminum alloys themselves have lower compressive and shear strength than steel, further amplifying the risk of localized failure in bolt and pin connections. Therefore, the industry urgently needs a rigid chord connection structure that requires no special tools, automatically aligns and blindly assembles, has no clearance, transmits force evenly throughout, can be repeatedly disassembled and reassembled without damage, and is suitable for all-weather emergency scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide a dovetail joint connection device for emergency aluminum alloy truss bridge chords, aiming to improve the problems of existing bolted connections, such as slow assembly, easy loosening, seizing during disassembly, and low component reuse rate; and pin connections, such as poor fit clearance, poor fatigue resistance, weak composite stress, insufficient anti-loosening reliability, and permanent damage to pin holes.

[0007] This invention is implemented as follows:

[0008] A dovetail joint connection device for emergency aluminum alloy truss bridge chords includes two chords. A first connector and a second connector are respectively provided at opposite ends of the two chords. The first connector and the second connector are connected to the two chords. The first connector has a dovetail mortise, and the second connector has a dovetail tenon, which is inserted into the dovetail mortise. A first limiting hole is provided on the first connector corresponding to the dovetail mortise. A second limiting hole is provided on the dovetail tenon aligned with the first limiting hole. After the first and second limiting holes are aligned, a trapezoidal locking member is inserted.

[0009] Preferably, the first connector and the second connector are respectively connected to the two chords via multiple shafts. The chords are integrally forged from aluminum alloy. Two rows of pin holes are longitudinally provided on both sides of one end of the chord. The first connector and the second connector are each provided with a connecting plate at the end facing the chord. The connecting plate is provided with through holes aligned with the pin holes. The shafts pass through the pin holes and through holes to connect the first connector or the second connector to the chord.

[0010] Preferably, the dovetail tenon and the dovetail mortise have trapezoidal cross sections that are wider at the top and narrower at the bottom, and the angle between the two beveled sides of the dovetail tenon and the horizontal direction is 12°; all contact surfaces of the dovetail tenon and the dovetail mortise are polished.

[0011] Preferably, the trapezoidal locking member is made of stainless steel and has a trapezoidal structure that is wider at the top and narrower at the bottom. The first limiting hole and the second limiting hole are adapted to the size of the trapezoidal locking member.

[0012] Preferably, the trapezoidal locking component includes two wedges and a miniature spring preload plate. The two wedges fit together to form a trapezoidal locking component, and the two wedges are inserted from both sides of the first connector. The side of the two wedges that fits against the first connector has an installation groove, and the miniature spring preload plate is installed in the installation groove. The opposite side of the two wedges has an anti-slip texture, and the wider end of the wedge serves as a hammering end. The two wedges are inserted into the first limiting hole and the second limiting hole from both sides of the first connector by hammering, and the two wedges squeeze each other to achieve the purpose of locking.

[0013] Preferably, one end of the trapezoidal locking member is provided with a mounting plate, the outer end of the mounting plate is provided with a handle, and the top and bottom ends of the side of the mounting plate facing the trapezoidal locking member are respectively provided with force springs. The end of the force spring that is in contact with the first connector is provided with an end plate, and the end plate is provided with bolt holes. The end plate is fixed to the first connector by bolts passing through the bolt holes.

[0014] Preferably, it also includes a dual-axis inclinometer and a control box. The dual-axis inclinometer is fixed to the second connector, and the control box is fixed to the chord. The dual-axis inclinometer is electrically connected to the control box and is used to monitor the deformation at the connection between the first connector and the second connector; this facilitates the monitoring of the deformation of the temporary emergency dovetail joint device.

[0015] Preferably, the dual-axis inclinometer has countersunk holes at its corners, and the dual-axis inclinometer is fixed to the second connector by bolts passing through the countersunk holes; the dual-axis inclinometer has spring wires on its side, and the bottom end of the spring wires has a connecting female.

[0016] Preferably, the control box has a male connector on its side, which is electrically connected to a female connector; the control box has an operation panel on its front, and symmetrical fixing feet on both sides of its back, with multiple fixing holes from top to bottom on each fixing foot, and the control box is fixed to the chord by bolts passing through the fixing holes; the control box has a battery inside, and a charging slot on its side for charging the battery.

[0017] Preferably, the control box integrates a control module, which is electrically connected to a signal acquisition module, a data analysis module, a wireless communication module, a remote early warning module, and a power supply module. The control module controls the operation of the dual-axis inclinometer and the control box. The signal acquisition module acquires the inclinometer's inclinometer data. The data analysis module analyzes the inclinometer data to determine if it exceeds a set threshold. The wireless communication module transmits the monitored data remotely to a terminal. The remote early warning module issues a remote warning to the terminal when deformation data is abnormal. The power supply module, in conjunction with a battery, supplies power to the control box and the dual-axis inclinometer.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. This invention does not require special equipment such as torque wrenches or power tools; the sliding assembly can be completed entirely by human labor. It can be blindly aligned in the dark at night. The assembly time of a single node is extremely short, which is convenient for emergency repairs. The assembly efficiency is greatly improved compared to traditional bolt connections. It perfectly matches the needs of rapid clearing after disasters and accidents, and realizes phased assembly of first positioning and bearing, and then locking and reinforcing.

[0020] 2. The invention has an overall threadless structure, so mud, sand and gravel are not easily stuck on the mating surface; the tenon and mortise body and the locking parts are made of aluminum alloy and stainless steel, which are both corrosion-resistant materials, so it can be used stably in waterways, coastal high salt spray and cold and frozen environments, without the need for regular rust removal and fastening maintenance; it does not rely on external power, so it can be used normally in emergency scenarios where there is no power supply in the field.

[0021] 3. The present invention adopts surface contact force transmission, with uniform stress distribution and load-bearing capacity higher than that of pin connection; there is no clearance, eliminating the root cause of fretting wear and significantly extending fatigue life.

[0022] 4. The present invention can be disassembled by simply knocking out the locking parts in the reverse direction and pushing out the tenon horizontally, without the problems of thread corrosion and seizing, or permanent deformation due to extrusion of the hole wall; the entire device can be disassembled and reused multiple times, which greatly reduces the production, storage and replacement costs of emergency aluminum alloy trusses and improves equipment turnover efficiency.

[0023] 5. The trapezoidal locking component of this invention forms a secondary self-locking protection, which will not loosen on its own under wind vibration and heavy load impact. It eliminates easily damaged small parts such as cotter pins and snap rings, and eliminates structural safety hazards caused by the failure of auxiliary anti-loosening components.

[0024] 6. This invention is equipped with a dual-axis inclinometer and a control box. The two work together to monitor the deformation of the emergency-connected chord in real time, and can issue a remote warning when abnormal deformation occurs, so that staff can handle it in a timely manner. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0026] Figure 2 This is a schematic diagram showing the structure after disassembly of Embodiment 1 of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of the string member of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the first connector of the present invention;

[0029] Figure 5This is a schematic diagram of the structure of the second connector of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0031] Figure 7 This is a schematic diagram of the trapezoidal locking member according to Embodiment 2 of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0033] Figure 9 This is a schematic diagram of the trapezoidal locking member according to Embodiment 3 of the present invention;

[0034] Figure 10 This is a schematic diagram of the structure of Embodiment 4 of the present invention;

[0035] Figure 11 This is a schematic diagram of the structure of the dual-axis inclinometer of the present invention;

[0036] Figure 12 This is a schematic diagram of the control box of the present invention;

[0037] Figure 13 This is a structured block diagram of the internal components of the control box of this invention;

[0038] Figure 14 This is a deformation displacement amplitude cloud map of Embodiment 1 of the present invention;

[0039] Figure 15 This is a cloud map showing the deformation displacement amplitude of the conventional bolted connection of the present invention.

[0040] In the diagram: 1. Stringer; 11. Pin hole; 2. First connector; 21. Connecting plate; 22. Through hole; 23. Dovetail tenon; 24. First limit insertion hole; 3. Second connector; 31. Dovetail tenon; 32. Second limit insertion hole; 4. Shaft; 5. Trapezoidal locking element; 51. Wedge; 511. Mounting groove; 512. Anti-slip texture; 513. Hammer end; 52. Miniature spring preload plate; 53. Mounting plate; 54. Handle; 55. Force spring; 56. End plate; 57. Bolt hole; 6. Dual-axis inclinometer; 61. Countersunk hole; 62. Spring wire; 63. Female connector; 7. Control box; 71. Male connector; 72. Control panel; 73. Fixing foot; 74. Fixing hole; 75. Charging slot. Detailed Implementation

[0041] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] The following description, in conjunction with the accompanying drawings and specific embodiments, provides further details:

[0043] Example 1

[0044] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, this embodiment provides a dovetail joint connection device for emergency aluminum alloy truss bridge chords. The overall assembly includes two aluminum alloy chords 1. A first connector 2 and a second connector 3 are respectively installed at the joint ends of the two chords 1. Each of the first connector 2 and the second connector 3 is equipped with multiple shafts 4, which form a rigid connection with the corresponding chord 1. Each chord 1 is manufactured using an integrated aluminum alloy forging process. Two rows of pin holes 11 are arranged longitudinally on both sides of the end of the chord 1 facing the connector. A connecting plate 21 is integrally formed at the end of the first connector 2 and the second connector 3 near the chord 1. Through holes 22 are opened on the connecting plate 21 at the positions corresponding to the pin holes 11 of the chord 1. During assembly, the shafts 4 are simultaneously passed through the pin holes 11 and the through holes 22, thereby locking and fixing the first connector 2 and the second connector 3 to the ends of the two chords 1 respectively. The first connector 2 has a dovetail mortise 23 on its mating end face facing the second connector 3. The second connector 3 extends outward to form a dovetail tenon 31 corresponding to the position of the dovetail mortise 23. The dovetail tenon 31 can slide completely into the dovetail mortise 23 to complete the initial alignment and splicing. The cross-section of the dovetail tenon 31 and the dovetail mortise 23 is uniformly designed as a trapezoidal shape that is wider at the top and narrower at the bottom. The inclined contact surfaces on both sides of the dovetail tenon 31 maintain an angle of 12° with the horizontal direction. All contact surfaces of the dovetail tenon 31 and the dovetail mortise 23 that can fit together are polished. The smooth contact surfaces after polishing can reduce the resistance of sliding into the assembly, facilitate blind assembly in the dark, and at the same time make the contact surfaces under force fit more tightly after splicing, eliminating assembly gaps. The first connector 2 has a first limiting insertion hole 24 in the through area of ​​the dovetail mortise 23. The dovetail tenon 31 has a second limiting insertion hole 32 corresponding to the through position of the first limiting insertion hole 24. When the dovetail tenon 31 is fully slid into the dovetail mortise 23 and the two insertion holes are fully aligned, the trapezoidal locking member 5 is inserted into the insertion hole to lock the node. The trapezoidal locking member 5 is made of stainless steel and has the same upper and lower trapezoidal structure. The internal dimensions of the first limiting insertion hole 24 and the second limiting insertion hole 32 are fully compatible with the external contour dimensions of the trapezoidal locking member 5. The self-locking fixation of the mortise and tenon joint structure is achieved by the trapezoidal wedge structure. The entire assembly process can be completed by manual pushing and hammering, without the need for torque wrenches, electric wrenches or other special construction tools, which is suitable for the use of emergency repair and rapid erection.

[0045] like Figure 14 and Figure 15As shown, a comparison of structural deformation reveals that when the truss chords are connected by bolts, the overall structural displacement reaches 1.037 mm, with the deformation concentrated at the connection nodes. The overall deformation of the chord is minimal, and its stress relies on local bearing pressure and shear force transmission through the bolt holes. The node stiffness is poor, significantly affecting the overall geometric stability of the truss. In contrast, when mortise and tenon joints are used, the maximum structural displacement is only 0.2426 mm. The deformation is evenly distributed along the entire length of the chord and exhibits a symmetrical bending overall deformation pattern. Force is transmitted through the interlocking of the mortise and tenon contact surfaces, resulting in superior node stiffness. The maximum deformation of the bolted connection is more than four times that of the mortise and tenon connection, and its overall stiffness is much lower. The deformation mechanisms of the two are significantly different. The deformation of the bolted connection is dominated by local sliding and compression at the nodes, while the deformation of the mortise and tenon connection is mainly due to the overall bending deformation of the members, exhibiting superior overall coordinated stress-bearing performance. Traditional bolted connections have several drawbacks when applied to aluminum alloy truss structures. Bolt holes weaken the cross-sectional area of ​​chord members, reducing local stiffness at the nodes. Furthermore, the gap between the bolt and the hole wall allows for sliding and compressive deformation under load, leading to additional structural displacement. In addition, the compressive and shear strength of aluminum alloy is much lower than that of steel, making the bolt hole walls highly susceptible to significant local compressive deformation. This not only easily leads to failures such as hole wall tearing and bolt loosening, failing to meet the requirements of repeated disassembly and reassembly in prefabricated structures, but also reduces the overall stiffness of the truss due to weak node stiffness and large local deformation, making the structure more prone to lateral instability and node rotation. Under repeated loads and vibrations, the structural stability will further deteriorate. In conclusion, the overall stiffness and structural stability of aluminum alloy trusses using mortise and tenon joints are far superior to those of traditional bolted connections.

[0046] Example 2

[0047] like Figure 6 and Figure 7As shown, this embodiment refines and optimizes the internal structure of the trapezoidal locking member 5 based on embodiment 1. The structure and assembly method of other basic components such as the chord 1, the first connector 2, the second connector 3, the dovetail mortise 23, the dovetail tenon 31, and the shaft 4 are completely consistent with those of embodiment 1. In this embodiment, the trapezoidal locking member 5 is formed by combining two sets of wedges 51 and a miniature spring preload plate 52. The two wedges 51 are fitted together to form the complete trapezoidal locking member 5. The two wedges 51 are inserted laterally into the through cavity of the first limiting hole 24 and the second limiting hole 32 from the left and right sides of the first connector 2, respectively. Each wedge 51 has an installation groove 511 on one side that fits against the outer wall of the first connector 2. A miniature spring pretensioner 52 is snapped and fixed inside the installation groove 511. The miniature spring pretensioner 52 can continuously apply lateral pretension force to the two wedges 51 to prevent the wedges 51 from loosening and falling out under vibration conditions. The mating end faces of the two wedges 51 are processed with anti-slip texture 512. The anti-slip texture 512 can increase the frictional resistance between the two wedges 51 and further improve the self-locking and anti-loosening effect. The wider end of the wedge 51 serves as the exposed hammering end 513. During on-site assembly, construction workers use hand hammers to strike the hammering ends 513 of the left and right wedge blocks 51 respectively, gradually hammering the two wedge blocks 51 into the insertion cavity from both sides of the first connector 2. The two wedge blocks 51 are squeezed and wedged together inside the insertion hole, and the splicing contact surface of the dovetail tenon 31 and the dovetail mortise 23 is locked by the pressure of the inclined surface, thus completing the overall locking of the node. When disassembling later, the two wedge blocks 51 can be removed by hammering the ends of the wedge blocks 51 in the opposite direction, and the dovetail tenon 31 can be pushed out horizontally to complete the non-destructive disassembly. The entire set of components can be disassembled and reused multiple times.

[0048] Example 3

[0049] like Figure 8 and Figure 9As shown, this embodiment retains the basic splicing structure of embodiment 1, only replacing the new trapezoidal locking component 5 with a spring automatic pre-tightening structure. All other connecting components, dimensional parameters, and assembly logic remain unchanged. In this embodiment, the outer end of the trapezoidal locking component 5 is integrally connected to a mounting plate 53. A handle 54 is fixedly installed on the end face of the mounting plate 53 facing the outside of the device. The handle 54 facilitates the construction personnel to grasp and lift the trapezoidal locking component 5 to complete the disassembly and assembly operations. Two sets of force-applying springs 55 are symmetrically installed at the top and bottom of the side of the mounting plate 53 facing the main body of the trapezoidal locking component 5. The end of the force-applying spring 55 away from the mounting plate 53 is fixedly connected to an end plate 56. Bolt holes 57 are opened on the surface of the end plate 56. The construction personnel use bolts to pass through the bolt holes 57 to lock the end plate 56 to the outer wall of the first connector 2. Under normal conditions, the force spring 55 is continuously in a compressed and stored energy state. After assembly, the force spring 55 continuously applies an inward pre-tightening force to the trapezoidal locking member 5 through the end plate 56 and the mounting plate 53. Under the continuous action of vehicle dynamic load and wind vibration, the spring pre-tightening force counteracts the tendency of the trapezoidal locking member 5 to loosen outward, further improving the anti-loosening performance of the joint in long-term service. When it is necessary to disassemble the connection joint, the construction personnel hold the handle 54 on the outside of the mounting plate 53 and pull it outward to overcome the elasticity of the force spring 55 and pull the trapezoidal locking member 5 out of the first limit hole 24 and the second limit hole 32. The locking constraint of the dovetail tenon 31 and the dovetail mortise 23 is released, and the two chords 1 can be separated. There is no problem of thread corrosion and jamming throughout the process, which is suitable for long-term use in high salt spray and water-crossing emergency bridges.

[0050] Example 4

[0051] like Figure 10 , Figure 11 , Figure 12 , Figure 13 and Figure 14As shown, this embodiment adds a real-time deformation online monitoring component to the existing embodiment 1. It can be used synchronously with any of the trapezoidal locking parts 5 in embodiments 2 and 3. The assembly structure of the basic chord 1 and the tenon joint is completely based on the design of embodiment 1. The newly added monitoring component includes two core components: a dual-axis inclinometer 6 and a control box 7. The dual-axis inclinometer 6 is bolted to the outer wall of the second connector 3 and is used to collect inclination change data at the splicing node of the first connector 2 and the second connector 3 in real time. This data is used to determine whether the splicing node has deformed beyond the safety threshold, thus realizing online monitoring of the structural safety of the emergency bridge truss during its service life. Countersunk holes 61 are opened at the four corners of the dual-axis inclinometer 6. The fastening bolts pass through the countersunk holes 61 to fix the dual-axis inclinometer 6 flat and close to the surface of the second connector 3. The countersunk hole 61 design can avoid the bolt end protruding and causing bump damage. A spring wire 62 is led out from the side of the dual-axis inclinometer 6. The spring wire 62 has tensile and rebound properties and can adapt to slight displacement deformation of the component. A connecting female head 63 is installed at the bottom of the spring wire 62. The control box 7 is fixedly installed on the side wall of the chord 1. A male connector 71 is provided on the side of the control box 7, which can be quickly plugged into the female connector 63 at the bottom of the spring wire 62 to establish electrical connection, enabling the transmission of data collected by the dual-axis inclinometer 6 to the control box 7. A control panel 72 is located on the front of the control box 7, allowing on-site personnel to view real-time monitoring data and manually set deformation warning thresholds. Two sets of fixing feet 73 are symmetrically arranged on the back of the control box 7. Each set of fixing feet 73 has multiple fixing holes 74 along the vertical direction. Personnel can select the corresponding fixing hole 74 according to the installation height of the chord 1 and use bolts to securely lock the control box 7 to the surface of the chord 1. A built-in battery is located inside the control box 7. A charging slot 75 is provided on the outer wall of the control box 7. An external charging device can be inserted into the charging slot 75 to charge the battery. In emergency field scenarios without external power supply, the battery can independently provide continuous power to the entire monitoring system. The control box 7 integrates a control module, which is electrically connected to the signal acquisition module, data analysis module, wireless communication module, remote early warning module, and power supply module. The control module coordinates and manages the overall operation of the dual-axis inclinometer 6 and the control box 7. The signal acquisition module continuously reads the raw inclination data transmitted by the dual-axis inclinometer 6 and stably transmits the data to the data analysis module. The data analysis module has a built-in preset safe inclination threshold and compares the acquired inclination values ​​in real time to automatically determine whether the node deformation exceeds the safe range. The wireless communication module remotely transmits all monitoring data to the back-end terminal device, allowing managers to remotely view the bridge node status in real time. When the data analysis module determines that the deformation exceeds the limit, the remote early warning module automatically pushes an early warning signal to the remote terminal to promptly remind on-site personnel to carry out structural maintenance. The power supply module connects to the battery to stably supply working power to all functional modules inside the control box 7 and the external dual-axis inclinometer 6. The entire monitoring system can operate synchronously around the clock, ensuring the structural safety of the emergency aluminum alloy truss bridge during long-term service.

[0052] Instructions for use: When erecting an emergency aluminum alloy truss bridge, first align the connecting plates 21 at the ends of the two aluminum alloy chords 1 with the corresponding connectors. Then, pass the shaft 4 through the pin holes 11 and 22 of the connecting plates 21 in sequence to rigidly fix the first connector 2 and the second connector 3 to the ends of the two chords 1. Next, slide the dovetail tenon 31 of the second connector 3 into the dovetail mortise 23 of the first connector 2 along the polished smooth contact surface to complete the initial alignment. After the first limiting insertion hole 24 aligns with the second limiting insertion hole 32, use a trapezoidal locking member 5 with the corresponding structure for locking. The trapezoidal locking member 5 can have different structures. When using a basic integrated trapezoidal locking member 5, directly hammer and push it into the insertion hole to achieve self-locking. When using a split wedge block 51 type locking member, hammer the wedge block 51 with a micro-spring pre-tightening plate 52 into both sides of the connector, relying on the lateral pre-tightening elasticity to prevent loosening. Locking members with a spring-assisted automatic pre-tightening structure are pre-locked by bolts. The end plate 56 is fixed to the outer wall of the connector. The compressed force spring 55 continuously provides pre-tightening tension. If real-time monitoring of node deformation is required, the dual-axis inclinometer 6 can be fixed to the outer wall of the second connector 3 through the countersunk bolt 61. The spring wire 62 is connected to the female connector 63 and the male connector 71 of the control box 7 on the side wall of the chord 1. Powered by the battery in the box, the internal modules collect and analyze the inclination data and transmit it remotely, and provide over-limit warnings. When the bridge is dismantled, the integrated locking part can be directly hammered out. The split wedge 51 is hammered in the opposite direction and then pulled out. The spring pre-tightening grip handle 54 is pulled outward to overcome the spring force and remove the locking part. After unlocking, the dovetail tenon can be pushed out horizontally to separate the two chords 1. All components can be disassembled and reused repeatedly. The whole operation only requires manual pushing and hammering. No professional torque or power tools are required. It is suitable for rapid emergency erection in the field and use in complex scenarios such as high salt spray and wading.

[0053] In summary, compared with existing technologies, this application eliminates the need for specialized equipment such as torque wrenches and power tools, allowing for manual assembly. Blind assembly and alignment are possible even in low-light conditions. The assembly time for a single node is extremely short, facilitating emergency repairs. Assembly efficiency is significantly improved compared to traditional bolt connections, perfectly matching the rapid clearing needs of disaster and accident sites. It enables phased assembly, with initial placement for load bearing followed by tightening and reinforcement. The overall threadless structure prevents mud, sand, and gravel from easily getting stuck on the mating surface. The tenon and mortise body and locking components are made of corrosion-resistant aluminum alloy and stainless steel, ensuring stable use in wading rivers, coastal high-salt-spray environments, and frigid, cold environments, eliminating the need for regular rust removal and tightening maintenance. It does not rely on external power, allowing for normal construction in emergency scenarios without electricity in the field. The surface contact force transmission ensures uniform stress distribution and a higher load-bearing capacity than pin connections. The absence of clearance eliminates the root cause of fretting wear, significantly extending fatigue life. Disassembly requires only knocking out the locking parts in the reverse direction and pushing out the tenon horizontally, eliminating problems such as thread corrosion and seizing, and permanent deformation due to hole wall compression. The entire device can be disassembled and reused multiple times, significantly reducing the production, storage, and replacement costs of emergency aluminum alloy trusses and improving equipment turnover efficiency. The trapezoidal locking part 5 forms a secondary self-locking protection, preventing it from loosening under wind vibration and heavy load impacts. It eliminates easily damaged small parts such as cotter pins and snap rings, thus eliminating structural safety hazards caused by the failure of auxiliary anti-loosening components.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dovetail joint device for emergency aluminum alloy truss bridge chords, characterized in that, It includes two string rods (1), and a first connector (2) and a second connector (3) are respectively provided at opposite ends of the two string rods (1). The first connector (2) and the second connector (3) are respectively connected to the two string rods (1). The first connector (2) is provided with a dovetail mortise (23), and the second connector (3) is provided with a dovetail tenon (31). The dovetail tenon (31) is inserted into the dovetail mortise (23). A first limiting insertion hole (24) is provided through the first connector (2) corresponding to the position of the dovetail mortise (23). The dovetail tenon (31) is aligned with the first limiting insertion hole (24) and a second limiting insertion hole (32) is provided through the first limiting insertion hole (24). After the first limiting insertion hole (24) and the second limiting insertion hole (32) are aligned, a trapezoidal locking member (5) is inserted.

2. The dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 1, characterized in that, The first connector (2) and the second connector (3) are respectively connected to the two chords (1) through multiple shafts (4); the chords (1) are integrally forged from aluminum alloy, and two rows of pin holes (11) are longitudinally provided on both sides of one end of the chords (1). The first connector (2) and the second connector (3) are both provided with connecting plates (21) at the end facing the chords (1). The connecting plates (21) are provided with through holes (22) aligned with the pin holes (11). The shafts (4) pass through the pin holes (11) and the through holes (22) to connect the first connector (2) or the second connector (3) to the chords (1).

3. The dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 1, characterized in that, The dovetail tenon (31) and the dovetail mortise (23) have a cross-section that is wider at the top and narrower at the bottom. The angle between the beveled sides of the dovetail tenon (31) and the horizontal direction is 12°. All the contact surfaces of the dovetail tenon (31) and the dovetail mortise (23) are polished.

4. The dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 1, characterized in that, The trapezoidal locking member (5) is made of stainless steel. The trapezoidal locking member (5) adopts a trapezoidal structure that is wider at the top and narrower at the bottom. The first limiting hole (24) and the second limiting hole (32) are adapted to the size of the trapezoidal locking member (5).

5. A dovetail joint connection device for emergency aluminum alloy truss bridge chords according to claim 1, characterized in that, The trapezoidal locking component (5) includes two wedges (51) and a miniature spring preload plate (52). The two wedges (51) are fitted together to form the trapezoidal locking component (5). The two wedges (51) are inserted from both sides of the first connector (2). The two wedges (51) are fitted to the side of the first connector (2) with an installation groove (511). The miniature spring preload plate (52) is installed in the installation groove (511). The opposite side of the two wedges (51) is provided with anti-slip texture (512). The wider end of the wedges (51) is used as the hammering end (513). The two wedges (51) are inserted into the first limiting hole (24) and the second limiting hole (32) from both sides of the first connector (2) by hammering. The two wedges (51) squeeze each other to achieve the purpose of locking.

6. A dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 1, characterized in that, The trapezoidal locking member (5) has a mounting plate (53) at one end, and a handle (54) at the outer end of the mounting plate (53). The top and bottom ends of the mounting plate (53) facing the trapezoidal locking member (5) are respectively provided with force springs (55). The end of the force spring (55) that is in contact with the first connector (2) is provided with an end plate (56). The end plate (56) is provided with bolt holes (57). The end plate (56) is fixed to the first connector (2) by bolts passing through the bolt holes (57).

7. A dovetail joint device for emergency aluminum alloy truss bridge chords according to any one of claims 1-6, characterized in that, It also includes a dual-axis inclinometer (6) and a control box (7). The dual-axis inclinometer (6) is fixed on the second connector (3), and the control box (7) is fixed on the chord (1). The dual-axis inclinometer (6) and the control box (7) are electrically connected to monitor the deformation at the connection between the first connector (2) and the second connector (3). This facilitates the monitoring of the deformation of the temporary emergency dovetail joint connection device.

8. A dovetail joint connection device for emergency aluminum alloy truss bridge chords according to claim 7, characterized in that, The dual-axis inclinometer (6) has a countersunk hole (61) at its corner. The dual-axis inclinometer (6) is fixed to the second connector (3) by a bolt passing through the countersunk hole (61). The dual-axis inclinometer (6) has a spring wire (62) on its side. The bottom end of the spring wire (62) has a connecting female head (63).

9. A dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 8, characterized in that, The control box (7) has a male connector (71) on its side, which is electrically connected to the female connector (63). The control box (7) has an operating panel (72) on its front side, and fixed feet (73) are symmetrically arranged on both sides of the back of the control box (7). The fixed feet (73) have multiple fixing holes (74) from top to bottom. The control box (7) is fixed to the chord (1) by bolts passing through the fixing holes (74). The control box (7) has a storage battery inside, and a charging slot (75) is provided on the side of the control box (7) for charging the storage battery.

10. A dovetail joint device for emergency aluminum alloy truss bridge chords according to claim 9, characterized in that, The control box (7) integrates a control module, which is electrically connected to a signal acquisition module, a data analysis module, a wireless communication module, a remote early warning module, and a power supply module. The control module is used to control the operation of the dual-axis inclinometer (6) and the control box (7). The signal acquisition module is used to acquire the inclinometer (6) inclinometer data. The data analysis module is used to analyze the inclinometer data acquired by the signal acquisition module and determine whether the inclinometer data exceeds the set threshold. The wireless communication module is used to remotely transmit the monitored data to the terminal. The remote early warning module is used to issue a remote early warning to the terminal when the deformation data is abnormal. The power supply module, together with the battery, provides power to the control box (7) and the dual-axis inclinometer (6).

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