A stress relaxation testing machine for PC steel bars

Abstract

This utility model relates to the field of testing equipment technology and discloses a PC steel bar stress relaxation testing machine, including a frame and a base plate. A clamping mechanism is provided on the top wall of the base plate, and an installation mechanism is provided on the inner wall of the frame. In the clamping mechanism, an electric push rod drives the connecting piece and connecting strip to move downwards, pulling the clamping arms rotatably connected to both sides of the outer wall of the connecting block in an arc motion. This causes the anti-slip pads at the top of the clamping arms to converge towards the center to clamp the steel bar. In the installation mechanism, a mounting base is fixed to the inner wall of the frame, a cylindrical seat is located at the upper end of the mounting base, and a damping rod is rotatably connected to the inner wall of the cylindrical seat. The positioning post on the outer wall of the damping rod slides along the slot of the cylindrical seat, driving the fixed arm at the front end of the damping rod to move axially to press the installation block and sensor. This utility model achieves stable clamping of the steel bar by driving the connecting rod with an electric push rod, preventing it from falling off under force. Simultaneously, the use of a spinning structure allows for quick assembly and disassembly of the sensor assembly, improving the safety and ease of maintenance of the equipment.

Description

Technical Field

[0001] This utility model relates to the field of testing equipment technology, and in particular to a stress relaxation testing machine for PC steel bars. Background Technology

[0002] PC steel bars are a key material in prestressed concrete structures and are widely used in bridges, railway sleepers and building construction. In order to ensure that the mechanical properties of PC steel bars meet the engineering safety standards, it is necessary to use a professional stress relaxation testing machine to conduct strict tensile and stress retention tests. During the test, the testing machine needs to apply a huge axial tensile force to the PC steel bars and maintain them in a high stress state for a long time.

[0003] However, existing stress relaxation testing machines have significant structural defects when clamping and fixing PC steel bars. Most existing clamping devices use manual tightening or simple direct pressure methods. When faced with the huge reaction force of high-strength PC steel bars, this fixing method often cannot guarantee a constant clamping force. As a result, the PC steel bars are prone to slight relative slippage or even instantaneous detachment during long-term tensile processes. Especially when the steel bar reaches its stress limit or breaks unexpectedly, due to the lack of a stable covering structure with self-locking or force-increasing effects, the out-of-control steel bar is very likely to fly off the test table. This not only damages expensive sensors and test components, but also poses a great threat to the personal safety of on-site operators.

[0004] Therefore, this utility model proposes a stress relaxation testing machine for PC steel bars to overcome the shortcomings of the prior art. Utility Model Content

[0005] In view of the problems in existing PC steel bar stress relaxation testing machines, the clamping and fixing methods mostly rely on manual tightening or simple direct pressure. When faced with the huge reaction force of high-strength steel bars, it is difficult to maintain a constant clamping force for a long time, which can easily lead to relative sliding or even falling off and flying out, thus causing safety accidents. In addition, the sensor components of existing equipment are cumbersome to install and disassemble, and it is difficult to quickly replace different specifications of measuring components. This utility model aims to provide a PC steel bar stress relaxation testing machine with an improved structure that can effectively solve the above problems.

[0006] This utility model provides a PC steel bar stress relaxation testing machine, including: a frame, and a base plate fixedly connected to the bottom wall of the frame, and also includes a clamping mechanism disposed on the top wall of the base plate, and an installation mechanism disposed on the inner wall of the frame.

[0007] The clamping mechanism includes a base, an electric push rod, a bracket, a connecting block, a clamping arm, an anti-slip pad, a connecting strip, and a connecting piece. The base is fixedly connected to the top wall of the base plate, the bottom wall of the electric push rod is fixedly connected to the top wall of the base, the outer wall of the electric push rod is slidably connected to the inner wall of the connecting block, the outer wall of the connecting block is fixedly connected to the inner wall of the bracket, and the bottom of the bracket is fixedly connected to the top wall of the base plate.

[0008] Furthermore, the bottom of the inner wall of the clamping arm is rotatably connected to the outer wall of the connecting block, the front end of the connecting strip is rotatably connected to the middle of the inner wall of the clamping arm, the top end of the electric push rod is fixedly connected to the connecting plate, the rear end of the connecting strip is rotatably connected to the inner wall of the connecting plate, and the anti-slip pad is fixedly connected to the top end of the inner wall of the clamping arm. The clamping arm, the connecting strip, and the connecting plate are combined by a rotatable connection to form a linkage structure that can convert the axial movement of the electric push rod into the radial clamping movement of the clamping arm.

[0009] Preferably, the installation mechanism includes a card holder, a cylindrical seat, a damping rod, a positioning post, a card slot, and a fixing arm. The outer wall of the card holder is fixedly connected to the inner wall of the frame, the cylindrical seat is fixedly connected to the upper end of the card holder, the damping rod is rotatably connected to the inner wall of the cylindrical seat, and the front end of the damping rod is fixedly connected to the fixing arm.

[0010] Preferably, a groove is formed on the surface of the cylindrical seat, the outer wall of the damping rod is fixedly connected to the positioning post, the positioning post is slidably fitted to the inner wall of the groove, and the groove extends circumferentially along the cylindrical seat and has an axial guiding slope. The positioning post slides in the groove with the slope to drive the damping rod to generate axial displacement.

[0011] Preferably, the installation mechanism also includes limiting posts, mounting blocks, and sensors. The limiting posts are fixedly connected to the outer wall of the card holder, and multiple limiting posts form a positioning space for accommodating the mounting blocks.

[0012] Preferably, the mounting block is positioned within the positioning space formed by the limiting post, and the sensor is fixedly connected to the outer wall of the mounting block, so that the mounting block is initially positioned by the limiting post.

[0013] Preferably, the fixed arm rotates with the damping rod and abuts against and presses against the mounting block or the outer wall of the sensor, thereby achieving a stable lock on the sensor by utilizing the axial contraction force of the damping rod.

[0014] Preferably, a sliding guide bushing is provided between the inner wall of the connecting block and the outer wall of the electric push rod, and the clamping arms are symmetrically arranged on the left and right sides of the connecting block to ensure that the electric push rod moves smoothly and achieves bidirectional centering clamping.

[0015] Preferably, the anti-slip pad is a rubber pad or a metal pad with anti-slip texture to increase the coefficient of friction of the contact surface with the steel rod.

[0016] This utility model has the following beneficial effects:

[0017] 1. This utility model, by setting a clamping mechanism on the top wall of the base plate, uses the telescopic movement of the electric push rod to drive the connecting plate and connecting strip to pull the clamping arm to rotate around the connecting block, so that the anti-slip pad on the inner wall of the clamping arm closes towards the center to clamp the steel rod. This solves the problem in the prior art that the steel rod is not stable enough when fixing the steel rod, which easily leads to the steel rod jumping out under force and causing safety hazards. It achieves the effect of using linkage transmission to realize the stable clamping of the steel rod, preventing the steel rod from falling off during the stress relaxation test, thereby effectively ensuring the personal safety of the experimental personnel and the stability of the equipment operation.

[0018] 2. This utility model, by setting an installation mechanism on the inner wall of the frame, uses a rotating damping rod to drive the positioning column to slide in the slot of the cylindrical seat. With the guidance of the slot, the fixed arm is driven to move axially and press the mounting block and sensor installed in the positioning space of the limiting column. This solves the problems of cumbersome and inefficient sensor assembly installation and disassembly process and inconvenience in replacing different specifications of measuring parts in the prior art. It achieves the effect of quickly positioning and locking the sensor, simplifying the operation steps and improving the convenience of equipment maintenance and component replacement. Attached Figure Description

[0019] Figure 1 This is a perspective view of a PC steel bar stress relaxation testing machine proposed in this utility model;

[0020] Figure 2 This is a front view of a PC steel bar stress relaxation testing machine proposed in this utility model;

[0021] Figure 3 A perspective view of the clamping mechanism of a PC steel bar stress relaxation testing machine proposed in this utility model;

[0022] Figure 4 This is a perspective view of the installation mechanism of a PC steel bar stress relaxation testing machine proposed in this utility model;

[0023] Figure 5 This is a cross-sectional view of the mounting mechanism of a PC steel bar stress relaxation testing machine proposed in this utility model;

[0024] Figure 6 This is a split view of the installation mechanism of a PC steel bar stress relaxation testing machine proposed in this utility model.

[0025] Legend:

[0026] 1. Frame; 2. Clamping mechanism; 201. Electric push rod; 202. Bracket; 203. Connecting block; 204. Clamping arm; 205. Anti-slip pad; 206. Connecting strip; 207. Connecting piece; 208. Base; 3. Mounting mechanism; 301. Damping rod; 302. Fixing arm; 303. Positioning post; 304. Cylindrical seat; 305. Sensor; 306. Card seat; 307. Mounting block; 308. Card slot; 309. Limiting post; 4. Base plate. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0028] Example:

[0029] Please refer to Figures 1 to 6 This utility model provides a PC steel bar stress relaxation testing machine, which aims to solve the problems in the prior art where insufficient clamping force during the steel bar fixing process easily leads to the steel bar jumping out under force and causing safety hazards, as well as the cumbersome installation and disassembly of the force sensing mechanism and poor compatibility.

[0030] Please refer to Figure 1 and Figure 2 A PC steel bar stress relaxation testing machine includes a frame 1 and a base plate 4 fixedly connected to the bottom wall of the frame 1. The frame 1 serves as the external support structure of the entire equipment, used to install various monitoring components and provide protective space. The base plate 4 serves as a basic bearing platform, used to stably support the force application mechanism. The PC steel bar stress relaxation testing machine also includes a clamping mechanism 2 set on the top wall of the base plate 4 and an installation mechanism 3 set on the inner wall of the frame 1. The clamping mechanism 2 is used to realize automatic centering and clamping of the PC steel bar and to prevent it from falling off. The installation mechanism 3 is used to realize the rapid positioning, installation and locking of the sensor 305 component.

[0031] Please refer to Figure 3The clamping mechanism 2 includes a base 208, an electric push rod 201, a bracket 202, a connecting block 203, a clamping arm 204, an anti-slip pad 205, a connecting strip 206, and a connecting piece 207. The base 208 is fixedly connected to the top wall of the base plate 4 and serves as the mounting base for the power source. The top wall of the base 208 is fixedly connected to the bottom wall of the electric push rod 201. The electric push rod 201 is vertically upward to provide axial driving force. The upper part of the outer wall of the electric push rod 201 is slidably connected to... The inner wall of the connecting block 203 is fixedly connected to the inner wall of the bracket 202. The bottom of the bracket 202 is fixedly connected to the top wall of the base plate 4 or to the inner wall of the frame 1. The bracket 202 is used to suspend and support the connecting block 203, so that the connecting block 203 remains in a fixed position. A sliding guide bushing is provided between the inner wall of the connecting block 203 and the outer wall of the electric push rod 201, thereby restricting the electric push rod 201 to move only up and down along the axial direction and preventing radial displacement.

[0032] Please refer to Figure 3 To achieve stable clamping of the steel bar and prevent it from falling off under high stress, the clamping mechanism 2 also includes a linkage assembly consisting of a connecting block 203, a clamping arm 204, a connecting strip 206, and a connecting piece 207. The bottom of the inner wall of the clamping arm 204 is rotatably connected to the left and right sides of the outer wall of the connecting block 203. The clamping arm 204 performs arc-shaped opening and closing movements with its bottom hinge point with the connecting block 203 as a fixed fulcrum. An anti-slip pad 205 is fixedly connected to the top of the inner wall of the clamping arm 204 to prevent slippage. The sliding pad 205 is made of rubber or has a metal pad with anti-slip texture to increase the friction coefficient of the contact surface with the steel rod. The connecting piece 207 is fixedly connected to the top telescopic rod of the electric push rod 201. The inner wall of the connecting piece 207 is rotatably connected to the rear end of the outer wall of the connecting strip 206. The front end of the outer wall of the connecting strip 206 is rotatably connected to the middle of the inner wall of the clamping arm 204, thereby forming a linkage transmission structure between the electric push rod 201, the connecting piece 207, the connecting strip 206 and the clamping arm 204.

[0033] When it is necessary to fix the steel bar, the electric push rod 201 retracts downward and drives the connecting piece 207 fixed at the top to move downward. The connecting piece 207 drives the rear end of the connecting strip 206, which is rotatably connected, to move downward synchronously. Since the front end of the connecting strip 206 is restrained by the position of the clamping arm 204, the connecting strip 206 generates a pulling force while moving downward and pulls the middle of the clamping arm 204 upward. This forces the clamping arm 204 to rotate in an arc around the rotation fulcrum on the left and right sides of the outer wall of the connecting block 203 towards the center. This causes the anti-slip pad 205 at the top of the clamping arm 204 to close towards the center to clamp the steel bar located in the center. Through this linkage force amplification mechanism, the axial tension of the electric push rod 201 can be converted into a strong radial clamping force of the clamping arm 204, ensuring that the equipment can stably fix the steel bar during the test and preventing the steel bar from jumping out of the equipment due to excessive force.

[0034] Please refer to Figure 4 , Figure 5 and Figure 6 The outer wall of the card holder 306 is fixedly connected to the lower left side of the inner wall of the frame 1. A cylindrical seat 304 is fixedly connected to the upper end of the card holder 306. A slot 308 is formed on the surface of the cylindrical seat 304. Limiting posts 309 are fixedly connected to the left side of the outer wall of the card holder 306. The limiting posts 309 form a positioning space for accommodating the mounting block 307. A damping rod 301 is rotatably connected to the inner wall of the cylindrical seat 304. A positioning post 303 is fixedly connected to the outer wall of the damping rod 301. The positioning post 303 is slidably fitted into the inner wall of the slot 308. The slot 308 has the following structure. The positioning post 303 is a spiral guide groove with an axial guiding slope. When the positioning post 303 moves along the slot 308, it can drive the damping rod 301 to generate an axial contraction displacement. The front end of the damping rod 301 is fixedly connected to a fixing arm 302. The mounting block 307 is placed in the positioning space formed by the limiting post 309. The left side of the outer wall of the mounting block 307 is fixedly connected to a sensor 305. The fixing arm 302 rotates with the damping rod 301 and can abut and press against the outer wall of the mounting block 307 or the sensor 305, thereby firmly locking the sensor 305 on the slot 306.

[0035] Working principle: When using the testing machine to fix the steel bar, the electric push rod 201 is activated and retracts downward. The electric push rod 201 drives the connecting piece 207 at the top to move downward. The connecting piece 207 drives the rear end of the rotating connecting strip 206 to move downward. The front end of the connecting strip 206 rotates accordingly and pulls the middle of the clamping arm 204 upward. Since the bottom of the clamping arm 204 is rotatably connected to the outer wall of the fixed connecting block 203, the clamping arm 204 moves in a centripetal arc around the fulcrum of the connecting block 203. The clamping arm 204 drives the anti-slip pad 205 at the top of the inner wall to close towards the center, thereby tightly clamping the steel bar located in the center. Through the clamping mechanism 2 set on the top wall of the base plate 4, the equipment can use the linkage force amplification principle to stably fix the steel bar, preventing the steel bar from jumping out of the equipment due to excessive force during the test and endangering personal safety.

[0036] Before testing with the testing machine, when installing or replacing the force sensing mechanism, the mounting block 307 with sensor 305 is placed in the positioning space formed by multiple limiting posts 309 on the left side of the outer wall of the card seat 306. The damping rod 301 inside the cylindrical seat 304 is rotated, and the positioning post 303 fixed on the outer wall of the damping rod 301 slides along the inner wall of the slot 308 opened in the cylindrical seat 304. Utilizing the axial guide slope of the slot 308, the positioning post 303 drives the damping rod 301 to generate axial contraction displacement during the movement. The damping rod 301 drives the fixed arm 302 at the front end to move inward and tightly abut against and press against the outer wall of the mounting block 307 and sensor 305. By setting the mounting mechanism 3 on the inner wall of the frame 1, the equipment can realize convenient installation and disassembly of the force sensing mechanism, making the replacement of the measuring components of the equipment more flexible and diverse.

Claims

1. A PC steel bar stress relaxation testing machine, comprising a frame (1) and a base plate (4) fixedly connected to the bottom wall of the frame (1). Its features are, The PC steel bar stress relaxation testing machine also includes a clamping mechanism (2) disposed on the top wall of the base plate (4) and an installation mechanism (3) disposed on the inner wall of the frame (1). The clamping mechanism (2) includes a base (208), an electric push rod (201), a bracket (202), a connecting block (203), a clamping arm (204), an anti-slip pad (205), a connecting strip (206), and a connecting piece (207). The base (208) is fixedly connected to the top wall of the base plate (4). The bottom wall of the electric push rod (201) is fixedly connected to the top wall of the base (208). The outer wall of the electric push rod (201) is slidably connected to the inner wall of the connecting block (203). The outer wall of the connecting block (203) is fixedly connected to the inner wall of the bracket (202). The bottom of the bracket (202) is fixedly connected to the top wall of the base plate (4).

2. The PC steel bar stress relaxation testing machine according to claim 1, characterized in that, The installation mechanism (3) includes a card holder (306), a cylindrical seat (304), a damping rod (301), a positioning post (303), a card slot (308), and a fixing arm (302). The outer wall of the card holder (306) is fixedly connected to the inner wall of the frame (1). The cylindrical seat (304) is fixedly connected to the upper end of the card holder (306). The damping rod (301) is rotatably connected to the inner wall of the cylindrical seat (304). The front end of the damping rod (301) is fixedly connected to the fixing arm (302).

3. The PC steel bar stress relaxation testing machine according to claim 1, characterized in that, The bottom of the inner wall of the clamping arm (204) is rotatably connected to the outer wall of the connecting block (203), the front end of the connecting strip (206) is rotatably connected to the middle of the inner wall of the clamping arm (204), the top end of the electric push rod (201) is fixedly connected to the connecting piece (207), the rear end of the connecting strip (206) is rotatably connected to the inner wall of the connecting piece (207), and the anti-slip pad (205) is fixedly connected to the top end of the inner wall of the clamping arm (204).

4. The PC steel bar stress relaxation testing machine according to claim 2, characterized in that, The cylindrical seat (304) has the slot (308), the outer wall of the damping rod (301) is fixedly connected to the positioning post (303), the positioning post (303) is slidably fitted to the inner wall of the slot (308), and the slot (308) extends along the circumference of the cylindrical seat (304) and has an axial guiding slope. The mounting mechanism (3) also includes a limiting post (309), a mounting block (307) and a sensor (305). The limiting post (309) is fixedly connected to the outer wall of the seat (306), and a positioning space for accommodating the mounting block (307) is formed between the limiting posts (309).

5. A PC steel bar stress relaxation testing machine according to claim 4, characterized in that, The mounting block (307) is disposed within the positioning space, and the sensor (305) is fixedly connected to the outer wall of the mounting block (307).

6. A PC steel bar stress relaxation testing machine according to claim 5, characterized in that, The fixed arm (302) rotates with the damping rod (301) and abuts against and presses against the outer wall of the mounting block (307) or the sensor (305).

7. A PC steel bar stress relaxation testing machine according to claim 1, characterized in that, A sliding guide bushing is provided between the inner wall of the connecting block (203) and the outer wall of the electric push rod (201), and the clamping arms (204) are symmetrically arranged on the left and right sides of the connecting block (203).

8. A stress relaxation testing machine for PC steel bars according to claim 1, characterized in that, The anti-slip mat (205) is a rubber mat or a metal mat with anti-slip texture.

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