A material strength detection device for construction engineering

Abstract

The application discloses a material strength detection equipment for building engineering, and belongs to the technical field of engineering material detection, which comprises a base, two coaxially distributed hydraulic cylinders are horizontally and fixedly installed on the top surface of the base, the output ends of the two hydraulic cylinders are oppositely arranged, a clamping assembly is arranged on the output end of each hydraulic cylinder, the clamping assembly comprises a box body which is fixedly installed on the output end of the hydraulic cylinder, the V-shaped groove structure of the movable clamping plate and the fixed clamping plate and the one-way check sawtooth anti-skid pattern are arranged, the contact area with the circular steel bar is increased, the auxiliary positioning is realized to prevent side sliding, the self-locking effect of "the tighter the more" is utilized to reduce the probability of slipping. In addition, in combination with the design of the "rigid and flexible combination" of the ejection rod and the elastic element in the pressurizing mechanism, the small unevenness on the surface of the steel bar can be compensated and additional anti-slippage resistance can be provided, the accurate guidance of the movable clamping plate by the guide rod is matched, the eccentric moment and the lateral shear force are eliminated, and the centration and stability of the clamping process are ensured.

Description

Technical Field

[0001] This invention relates to the field of engineering material testing technology, and more specifically, to a strength testing device for building materials. Background Technology

[0002] Currently, in the field of building materials testing technology, the testing of the tensile strength and yield strength of reinforcing bars is a key step in assessing the safety of building structures. This type of testing is typically performed using a hydraulic universal testing machine. During the test, the specimen is clamped at both ends by fixtures (usually wedge-shaped jaws), and an axial tensile force is applied through a hydraulic system until the specimen breaks.

[0003] However, existing tensile testing techniques for reinforcing bars have significant shortcomings in practical applications. Due to the influence of production processes (such as hot rolling) and storage environments, the surface of the reinforcing bars to be tested is usually covered with a dense, brittle oxide scale (iron scale) or rust layer. During tensile testing, as the specimen is subjected to axial tensile force and undergoes plastic deformation, the oxide scale on its surface cannot extend synchronously because its elongation rate is much lower than that of the reinforcing bar matrix, resulting in breakage and extensive peeling.

[0004] This peeling phenomenon can lead to serious consequences: First, the detached fine oxide scale particles easily embed and fill the anti-slip grooves of the clamp jaws. These hard particles form a medium layer similar to "balls" or "lubricant" between the jaws and the sample surface, reducing the coefficient of friction and effective clamping force between the jaws and the sample. Furthermore, the reduction in friction directly causes the sample to slip unexpectedly or experience uneven stress during the tensile process. Finally, under high-tonnage tensile loads, if the sample slips or breaks instantaneously due to unstable clamping, the enormous elastic potential energy accumulated in the system will be released instantly, generating a violent mechanical recoil. This recoil not only leads to distorted test data (such as failure to capture yield points) and can easily cause irreversible physical damage to the precision components of the equipment (such as load sensors and hydraulic cylinders), but also poses a serious risk of mechanical injury to surrounding operators.

[0005] Therefore, a strength testing device for building materials is proposed. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to provide a strength testing device for building materials, which can improve the stability of the testing process.

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A strength testing device for building materials, including a base;

[0009] Two coaxially distributed hydraulic cylinders are horizontally fixed on the top surface of the base, with the output ends of the two hydraulic cylinders arranged opposite each other;

[0010] Each hydraulic cylinder is equipped with a clamping assembly at its output end;

[0011] The clamping assembly includes a housing that is fixedly installed on the output end of the hydraulic cylinder; the side wall of the housing facing away from the corresponding hydraulic cylinder has an insertion hole, and the housing has a movable clamping plate and a fixed clamping plate that cooperate with each other, and the adjacent sides of the movable clamping plate and the fixed clamping plate are provided with anti-slip texture.

[0012] The inner wall of the box is equipped with a limiting plate, and the limiting plate and the insertion hole are symmetrically distributed on both sides of the fixed clamping plate;

[0013] Furthermore, an installation ring is movably embedded in the socket, and a first brush is fixedly installed on the inner ring side surface of the installation ring. The housing is equipped with a drive mechanism for driving the installation ring to rotate.

[0014] It also includes a gas supply mechanism for providing high-pressure gas into the chamber;

[0015] Both the fixed clamping plate and the moving clamping plate have multiple mounting holes, and each mounting hole is equipped with a pressure-applying mechanism.

[0016] Furthermore, a receiving cavity is provided in the side wall of the box, and the insertion hole penetrates the side wall of the box horizontally and passes through the receiving cavity; the mounting ring is rotatably embedded in the receiving cavity, and the central axis of the mounting ring coincides with the central axis of the insertion hole;

[0017] A gear is rotatably mounted in the cavity, and the outer circumferential wall of the mounting ring is evenly provided with tooth grooves that mesh with the gear along the circumferential direction.

[0018] Furthermore, a drive motor with its output end fixedly connected to the gear shaft is fixedly installed on the side wall of the housing.

[0019] Furthermore, the pressurizing mechanism includes a push rod that is vertically slidably installed in the mounting hole, and an elastic element is installed between the push rod and the corresponding mounting hole;

[0020] The end of the push rod away from the elastic element is provided with a cone-shaped tooth with the tip pointing upwards.

[0021] Furthermore, support legs are fixedly installed on the inner bottom wall of the box, and fixed clamps are fixedly installed on the top of the support legs;

[0022] A hydraulic rod is vertically fixedly installed on the inner top wall of the housing, and a movable clamping plate is fixedly installed on the output end of the hydraulic rod.

[0023] The central axes of both the moving clamp and the fixed clamp coincide with the axis of the hydraulic rod.

[0024] Furthermore, the drive motor is a dual-shaft output motor, and the gear is fixedly mounted on the first output shaft of the dual-shaft output motor; the air supply mechanism includes an air inlet opened on the side wall of the housing, and the air inlet and the socket are respectively set on the opposite side walls of the housing;

[0025] A fan blade is rotatably mounted inside the air inlet, and the central shaft of the fan blade is fixedly connected to the second output shaft of the dual-shaft output motor.

[0026] A removable dust filter is fixedly installed on the outside of the air inlet. The dust filter is used to filter large dust particles in the air entering the box.

[0027] Furthermore, a guide hole is provided on the moving clamp plate; a vertically arranged guide rod is provided inside the box, and the two ends of the guide rod are fixedly connected to the inner top wall and the inner bottom wall of the box, respectively.

[0028] The guide rod slides through the guide hole to restrict the circumferential rotation of the moving clamp during movement;

[0029] A buffer spring is fitted on the outer circumference of the guide rod, and the two ends of the buffer spring abut against the upper surface of the moving clamp and the inner top wall of the box, respectively.

[0030] Furthermore, the top wall of the fixed clamping plate and the bottom wall of the movable clamping plate are both designed with a V-shaped groove structure;

[0031] The anti-slip texture adopts a one-way reverse sawtooth design, wherein the inclination angle of the sawtooth is designed to be opposite to the direction of the movement trend of the steel bar when it is under tension.

[0032] Furthermore, a second brush is fixedly installed on both the upper and lower end faces of the limiting plate. The second brush is used to brush and clean the clamping surfaces of the fixed clamping plate and the moving clamping plate during the movement of the limiting plate.

[0033] The housing is equipped with an elastic telescopic mechanism for supporting the limiting plate and driving it to reset; wherein, the elastic telescopic mechanism is configured to: hold the limiting plate on the side of the fixed clamp plate close to the insertion hole in the natural state, and allow the limiting plate to retract and move away from the insertion hole when subjected to the pushing force of the reinforcing bar.

[0034] Furthermore, the elastic telescopic mechanism includes a guide sleeve that is horizontally fixedly installed on the inner side wall of the box. The guide sleeve and the insertion hole are located on opposite side walls of the box, and the central axis of the guide sleeve coincides with the central axis of the insertion hole.

[0035] A telescopic cavity is provided at one end of the guide sleeve near the insertion hole. A piston rod is slidably installed in the telescopic cavity, and a return spring abuts against the inner bottom wall of the telescopic cavity. A limiting plate is fixedly installed at one end of the piston rod that extends out of the guide sleeve.

[0036] Furthermore, an auxiliary support roller mechanism is provided between the housing and the base;

[0037] The auxiliary support roller mechanism includes a bracket installed at the bottom of the housing, with a mounting groove at the bottom of the bracket, and a load-bearing roller that rolls and contacts the top surface of the base is movably installed in the mounting groove.

[0038] The load-bearing rollers are used to share the weight of the cantilevered housing and the output end of the hydraulic cylinder.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] (1) This scheme increases the contact area with the round steel bar by setting the V-shaped groove structure of the moving clamp and the fixed clamp and the one-way anti-slip serration, thereby achieving auxiliary positioning to prevent side slippage. It also uses the self-locking effect of "the tighter it gets" to reduce the probability of slippage. In addition, the combination of the "rigid-flexible" top rod and elastic element design in the pressure mechanism can compensate for the slight unevenness of the steel bar surface and provide additional anti-slip resistance. With the precise guidance of the moving clamp by the guide rod, the eccentric moment and lateral shear force are eliminated, ensuring the centering and stability of the clamping process, thereby improving the accuracy of the test data.

[0041] (2) This solution utilizes a rotating first brush driven by an installation ring to pre-remove the oxide scale and rust layer from the surface of the reinforcing bar; secondly, a dual-axis motor drives the fan blades to form a directional positive pressure airflow, which, while cooling the motor, blows the removed debris directly out through the insertion hole, preventing it from entering the housing in reverse; finally, a second brush on the limiting plate automatically performs a "pre-contact" cleaning of the clamping plate surface during the insertion of the reinforcing bar, scraping residual impurities into the collection tank. This prevents clamping failure caused by impurity accumulation and ensures the cleanliness of the internal environment and the reliability of operation of the equipment.

[0042] (3) This solution absorbs and dissipates the huge axial recoil energy generated at the moment of steel bar fracture by setting buffer springs on the guide rods, preventing the moving clamp from hitting the box or causing structural disintegration. At the same time, the auxiliary support roller mechanism can share the weight of the cantilevered box, prevent the hydraulic cylinder seals from wearing and leaking oil due to long-term eccentric load, thereby extending the service life of the core components and improving the overall structural stability and operational safety of the equipment. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0044] Figure 2 This is a front cross-sectional view of the housing of the present invention;

[0045] Figure 3 For the present invention Figure 2 Schematic diagram of the structure of SS in China;

[0046] Figure 4 For the present invention Figure 2 Enlarged structural diagram at point A;

[0047] Figure 5 This is a schematic diagram of the structure of the clamping plate of the present invention;

[0048] Figure 6 For the present invention Figure 2 A magnified structural diagram at point B in the middle.

[0049] Explanation of the labels in the diagram:

[0050] 1. Base; 2. Hydraulic cylinder; 3. Housing; 4. Moving clamping plate; 5. Fixed clamping plate; 6. Limiting plate; 7. Mounting ring; 8. First brush; 9. Mounting hole; 10. Receiving cavity; 11. Gear; 12. Gear groove; 13. Drive motor; 14. Push rod; 15. Elastic element; 16. Hydraulic rod; 17. Fan blade; 18. Dust filter; 19. Guide rod; 20. Buffer spring; 21. Second brush; 22. Guide sleeve; 23. Piston rod; 24. Return spring; 25. Bracket; 26. Load-bearing roller. Detailed Implementation

[0051] 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] Example 1:

[0053] Please see Figures 1 to 6 A strength testing device for building materials, comprising a base 1;

[0054] Two coaxially distributed hydraulic cylinders 2 are horizontally fixedly installed on the top surface of the base 1, with the output ends of the two hydraulic cylinders 2 arranged opposite to each other;

[0055] Hydraulic cylinder 2 is a prior art in this field. The real-time tension data generated during its operation can be monitored and displayed by the matching force sensor and display terminal. Its specific structure and control principle are not the focus of improvement of this invention, so they will not be described in detail.

[0056] Each hydraulic cylinder 2 is equipped with a clamping assembly at its output end;

[0057] The clamping assembly includes a housing 3 fixedly mounted on the output end of the hydraulic cylinder 2. The housing 3 is made of high-strength metal. A flange is fixedly fitted onto the output end of the hydraulic cylinder 2, and a connecting seat corresponding to the shape and bolt hole position of the flange is provided on the force-bearing end face of the housing 3. During installation, the connecting seat is fitted against the flange surface, and the two are locked together by passing high-strength bolts through the bolt holes, thereby achieving a stable connection between the housing 3 and the output end of the hydraulic cylinder 2. An insertion hole penetrating the side wall of the housing 3 is provided on the side wall opposite to the corresponding hydraulic cylinder 2. The housing 3 contains a movable clamping plate 4 and a fixed clamping plate 5 that cooperate with each other, and anti-slip textures are provided on the adjacent sides of the movable clamping plate 4 and the fixed clamping plate 5.

[0058] A limiting plate 6 is provided on the inner side wall of the box body 3. The limiting plate 6 and the insertion hole are symmetrically distributed on both sides of the fixed clamping plate 5. The limiting plate 6 restricts the depth of the reinforcing bar inserted into the box body 3 to ensure that the insertion depth is the same each time.

[0059] The socket is circular, and an installation ring 7 is movably embedded in the socket. A first brush 8 made of steel wire is fixedly installed on the inner ring side surface of the installation ring 7. The housing 3 is provided with a drive mechanism for driving the installation ring 7 to rotate.

[0060] It also includes a gas supply mechanism for providing high-pressure gas into the housing 3;

[0061] Both the fixed clamping plate 5 and the movable clamping plate 4 are provided with multiple mounting holes 9, and each mounting hole 9 is equipped with a pressure mechanism. The top wall of the fixed clamping plate 5 and the bottom wall of the movable clamping plate 4 are designed with a V-shaped groove structure. Compared with the traditional flat clamping plate, the V-shaped structure can not only fit the surface of the round steel bar to greatly increase the contact area, but also play an auxiliary positioning role to prevent the steel bar from slipping or rolling during the clamping process.

[0062] The anti-slip texture employs a unidirectional reverse anti-serration design, where the inclination angle of the serrations is designed to be opposite to the direction of the steel bar's movement under tension. When the steel bar is subjected to a large axial tensile force, these reverse serrations can deeply embed into the oxide scale or matrix on the surface of the steel bar, producing a "tightening as it is pulled" self-locking effect. This improves the clamping effect on the steel bar, reduces the probability of slippage during tensioning, and enhances the stability of the testing process.

[0063] A receiving cavity 10 is provided in the side wall of the housing 3. The insertion hole passes through the side wall of the housing 3 and through the receiving cavity 10 in a horizontal direction. The mounting ring 7 is rotatably embedded in the receiving cavity 10, and the central axis of the mounting ring 7 coincides with the central axis of the insertion hole.

[0064] A gear 11 is rotatably mounted in the cavity 10, and tooth grooves 12 that mesh with the gear 11 are evenly provided on the outer circumferential wall of the mounting ring 7.

[0065] Furthermore, a drive motor 13 with its output end fixedly connected to the shaft of gear 11 is fixedly installed on the side wall of housing 3.

[0066] First, adjust the extension of the output end of hydraulic cylinder 2 so that the output ends of both hydraulic cylinders 2 are in a retracted state, and the reinforcing bar is suspended in the air, so that the two ends of the reinforcing bar are aligned with the two insertion holes.

[0067] Then, the drive motor 13 fixed on the side wall of the housing 3 is started, and the output shaft of the drive motor 13 drives the gear 11 to rotate. Since the gear 11 and the tooth groove 12 on the outer wall of the mounting ring 7 are always meshed, and the mounting ring 7 is axially constrained by the receiving cavity 10, the mounting ring 7 rotates smoothly at high speed in the receiving cavity 10. Subsequently, the output end of the control hydraulic cylinder 2 is extended. At this time, the steel bar to be tested is inserted axially and passes through the center hole of the mounting ring 7. The first steel wire brush 8 fixed on the inner side of the mounting ring 7 then rotates and brushes the surface of the steel bar 360 degrees, which plays the role of peeling off the oxide scale and rust layer on the surface of the steel bar.

[0068] When the end of the reinforcing bar is inserted into the box 3 through the insertion hole, the limiting plate 6 can physically block and position the axial displacement of the reinforcing bar, thereby limiting the depth of the reinforcing bar insertion into the clamping area; when different batches or different reinforcing bars are continuously tested, the clamping length (or force-bearing length) is always consistent each time, eliminating the interference variables introduced by different insertion depths, thereby improving the accuracy and comparability of the test data.

[0069] When the reinforcing bar to be tested is inserted into the box 3 along the axial direction and reaches the preset depth, the driving clamp 4 is fed towards the fixed clamp 5;

[0070] With the cooperation of the moving clamp 4 and the fixed clamp 5, the anti-slip texture on their opposite sides is used to firmly lock the steel bar to prevent slippage. Then, the output end of the hydraulic cylinder 2 is controlled to perform an axial retraction action, which drives the clamping assembly to apply a tensile load to the steel bar. At the same time, the matching detection system begins to collect and record the tensile force value and stress change of the steel bar in real time.

[0071] like Figure 2 , Figure 4 As shown, the pressurizing mechanism includes a top rod 14 that is vertically slidably installed in the mounting hole 9, and an elastic element 15 is installed between the top rod 14 and the corresponding mounting hole 9.

[0072] During the clamping process, as the moving clamping plate 4 descends and presses the reinforcing bar, the sliding top rod 14 is subjected to the reaction force from the surface of the reinforcing bar and retracts into the mounting hole 9, forcing the pre-tightening elastic element 15 to undergo elastic deformation. At this time, the compressed elastic element 15 continuously applies a pushing force to the sliding top rod 14, ensuring that the end of the sliding top rod 14 is always tightly pressed against the surface of the reinforcing bar. This "rigid-flexible" clamping method can effectively compensate for the small gaps caused by the unevenness of the reinforcing bar surface, thereby improving the fixing effect of the reinforcing bar.

[0073] The end of the push rod 14 away from the elastic element 15 is provided with a cone-shaped tooth with the tip pointing upward. Under the elastic force of the elastic element 15, the tooth can tightly abut against the surface of the steel bar, forming a multi-point auxiliary locking, thereby providing additional anti-slip resistance in addition to the main clamping force.

[0074] like Figure 2 As shown, a support leg is fixedly installed on the inner bottom wall of the box 3, and a fixed clamping plate 5 is fixedly installed on the top of the support leg. The support leg provides support for the fixed clamping plate 5 and raises the height of the fixed clamping plate 5, ensuring that the top wall of the fixed clamping plate 5 and the bottom wall of the socket are on the same plane and are fixedly installed on the inner bottom wall of the box 3.

[0075] The inner top wall of the housing 3 protrudes downwards, and a hydraulic rod 16 is vertically fixed on the bottom wall of the protruding part of the inner top wall of the housing 3. The movable clamping plate 4 is fixedly installed on the output end of the hydraulic rod 16. A through hole is opened on the side wall of the protruding part, and the output shaft of the drive motor 13 passes through the through hole. The ratio of the diameter of the through hole to the diameter of the output shaft of the drive motor 13 is 1.2-1.3, so as to prevent the output shaft of the drive motor 13 from contacting the side wall of the through hole.

[0076] The central axes of the moving clamp 4 and the fixed clamp 5 are both coincident with the axis of the hydraulic rod 16. Therefore, when the reinforcing bar that has passed through the insertion hole into the box 3 passes over the surface of the fixed clamp 5, the hydraulic rod 16 is activated. At this time, the output end of the hydraulic rod 16 drives the moving clamp 4 to move towards the fixed clamp 5 until the moving clamp 4 and the fixed clamp 5 clamp the reinforcing bar whose surface oxide scale and rust layer have been cleaned. The clamping effect is improved by the anti-slip texture on the adjacent side surfaces of the moving clamp 4 and the fixed clamp 5.

[0077] like Figure 2 As shown, the drive motor 13 is a dual-axis output motor, and the gear 11 is fixedly mounted on the first output shaft of the dual-axis output motor; the drive motor 13 is configured to drive the fan blade 17 to rotate synchronously while the drive gear 11 rotates; and the first output shaft of the dual-axis output motor passes through the through hole;

[0078] The gas supply mechanism includes an air inlet on the side wall of the housing 3, and the air inlet and the socket are respectively located on the opposite side walls of the housing 3.

[0079] A fan blade 17 is rotatably installed inside the air inlet. The central shaft of the fan blade 17 is fixedly connected to the second output shaft of the dual-shaft output motor. The fan blade 17, in a high-speed rotating state, is used to draw external air into the housing 3 through the air inlet and form a positive pressure airflow inside the housing 3. The positive pressure airflow is discharged from the inside to the outside through the gap of the first brush 8 in the socket.

[0080] While the mounting ring 7 drives the first brush 8 to peel off and clean the oxide scale and rust layer on the surface of the reinforcing steel, the high-speed rotating fan blade 17 continuously draws outside air into the housing 3 through the air inlet. Because the air inlet and the insertion hole are positioned opposite each other, the airflow entering the housing 3 creates directional wind pressure, forcing the airflow through the only exhaust channel on the housing 3—the insertion hole—and expelling it at high speed. The expelled airflow can pass through the bristles of the first brush 8, directly blowing out the fine impurities that have just been peeled off and are trapped in the gaps. This prevents oxide scale debris from reversing into the housing 3 and falling onto the surface of the clamping plate 5, further improving the surface stability of the clamping plate 5 and the operational stability of the device, thus improving the detection accuracy.

[0081] A removable dust filter 18 is fixedly installed on the outside of the air inlet. The dust filter 18 is used to filter large dust particles in the air entering the housing 3.

[0082] The dual-axis output motor is installed in the air duct path between the air inlet and the socket. After the outside air is drawn in by the fan blade 17, the airflow first flows over the surface of the dual-axis output motor to cool the motor. Then the airflow carries the heat generated by the motor and flows towards the socket and is discharged. Thus, the airflow achieves the triple function of cooling the motor, pressurizing the housing 3, and discharging slag from the socket.

[0083] like Figure 2 As shown, a guide through hole is provided on the moving clamp 4; a vertically arranged guide rod 19 is provided inside the box body 3, and the two ends of the guide rod 19 are respectively fixedly connected to the inner top wall and the inner bottom wall of the box body 3.

[0084] The guide rod 19 slides through the guide through hole to restrict the circumferential rotation of the moving clamp 4 during the movement process, so that the moving clamp 4 can only move up and down along the axial direction of the guide rod 19. The guide rod 19 can withstand the eccentric torque and lateral shear force generated during the clamping process, and prevent the output end of the hydraulic rod 16 from bending and deforming or failing to seal due to eccentric load, thus playing a role in protecting the hydraulic rod 16.

[0085] A buffer spring 20 is fitted onto the outer circumference of the guide rod 19, with its two ends abutting against the upper surface of the moving clamp 4 and the inner top wall of the housing 3, respectively. At the moment the steel sample breaks, the accumulated elastic potential energy is released instantly, causing the equipment to experience a significant axial recoil impact. At this time, the guide rod 19 acts as a radial constraint, limiting the horizontal swing freedom of the moving clamp 4; simultaneously, the buffer spring 20 rapidly deforms under pressure, effectively absorbing and dissipating the upward rebound impact energy of the moving clamp 4. This "guide + buffer" combination structure, on the one hand, prevents the moving clamp 4 from rigidly impacting the inner wall of the housing 3 due to severe vibration, avoiding damage or disintegration of the mechanical structure; on the other hand, the stable linear guidance ensures that the moving clamp 4 and the fixed clamp 5 always maintain precise alignment and engagement, thereby preventing accidental slippage or ejection of the sample due to tilted clamping posture, thus improving the operational safety of the equipment.

[0086] like Figure 2 , Figure 3 As shown, a second brush 21 is fixedly installed on both the upper and lower end faces of the limiting plate 6. The second brush 21 is used to brush and clean the clamping surfaces of the fixed clamping plate 5 and the moving clamping plate 4 during the movement of the limiting plate 6.

[0087] The housing 3 is equipped with an elastic telescopic mechanism for supporting the limiting plate 6 and driving it to reset; wherein, the elastic telescopic mechanism is configured to: hold the limiting plate 6 on the side of the fixed clamping plate 5 near the insertion hole in the natural state, and allow the limiting plate 6 to retract and move away from the insertion hole when subjected to the pushing force of the reinforcing bar.

[0088] The elastic telescopic mechanism includes a guide sleeve 22 that is horizontally fixed on the inner side wall of the housing 3. The guide sleeve 22 and the insertion hole are located on opposite side walls of the housing 3, and the central axis of the guide sleeve 22 coincides with the central axis of the insertion hole.

[0089] The guide sleeve 22 has a telescopic cavity at one end near the insertion hole. A piston rod 23 is slidably installed in the telescopic cavity. A return spring 24 abuts against the inner bottom wall of the telescopic cavity between the piston rod 23 and the telescopic cavity. The limiting plate 6 is fixedly installed at the end of the piston rod 23 that extends out of the guide sleeve 22.

[0090] When no steel bar is inserted into the socket, under the elastic force of the return spring 24, the piston rod 23 is in the extended state, positioning the limiting plate 6 in the standby position between the fixed clamping plate 5 and the socket;

[0091] When the reinforcing bar is inserted into the box 3 through the insertion hole, the reinforcing bar is first lifted up so that it is located between the fixed clamping plate 5 and the movable clamping plate 4 and is in a suspended state. Then the reinforcing bar is pushed through the insertion hole and into the box 3. At this time, the end of the reinforcing bar first touches the limiting plate 6 and overcomes the resistance of the return spring 24 to push the limiting plate 6 to move towards the guide sleeve 22.

[0092] Furthermore, a collection trough for collecting debris is provided on the inner bottom wall of the box 3;

[0093] During the movement of the limiting plate 6, the limiting plate 6 drives the second brush 21 on the upper and lower surfaces to move synchronously. The second brush 21 slides over the clamping surfaces of the fixed clamping plate 5 and the moving clamping plate 4 before the reinforcing bar, scraping off the residual oxide scale and debris on the surface into the collection groove at the bottom of the box 3. This ensures that the clamping plate surface is clean when the reinforcing bar enters the clamping area, thereby ensuring the clamping friction and improving the clamping effect on the reinforcing bar.

[0094] like Figure 2 As shown, an auxiliary support roller mechanism is also provided between the box body 3 and the base 1;

[0095] The auxiliary support roller mechanism includes a bracket 25 installed at the bottom of the housing 3. The bottom end of the bracket 25 is provided with a mounting groove, and a load-bearing roller 26 that rolls and contacts the top surface of the base 1 is movably arranged in the mounting groove.

[0096] The load-bearing rollers 26 are used to share the weight of the cantilevered housing 3 and the output end of the hydraulic cylinder 2, thereby preventing the hydraulic cylinder 2 seals from wearing out and leaking oil due to long-term cantilever, thus improving the structural stability of the equipment and extending its service life.

[0097] Working principle: First, adjust the extension of the output end of hydraulic cylinder 2 so that the output ends of both hydraulic cylinders 2 are in a retracted state, and the reinforcing bar is suspended in the air, so that the two ends of the reinforcing bar are aligned with the two insertion holes.

[0098] Then, the drive motor 13 fixed on the side wall of the housing 3 is started, and the output shaft of the drive motor 13 drives the gear 11 to rotate. Since the gear 11 and the tooth groove 12 on the outer wall of the mounting ring 7 are always meshed, and the mounting ring 7 is axially constrained by the receiving cavity 10, the mounting ring 7 rotates smoothly at high speed in the receiving cavity 10. Subsequently, the output end of the control hydraulic cylinder 2 is extended. At this time, the steel bar to be tested is inserted axially and passes through the center hole of the mounting ring 7. The first steel wire brush 8 fixed on the inner side of the mounting ring 7 then rotates and brushes the surface of the steel bar 360 degrees, which plays the role of peeling off the oxide scale and rust layer on the surface of the steel bar.

[0099] When the end of the reinforcing bar is inserted into the box 3 through the insertion hole, the limiting plate 6 can physically block and position the axial displacement of the reinforcing bar, thereby limiting the depth of the reinforcing bar insertion into the clamping area; when different batches or different reinforcing bars are continuously tested, the clamping length (or force-bearing length) is always consistent each time, eliminating the interference variables introduced by different insertion depths, thereby improving the accuracy and comparability of the test data.

[0100] When the reinforcing bar to be tested is inserted into the box 3 along the axial direction and reaches the preset depth, the driving clamp 4 is fed towards the fixed clamp 5;

[0101] With the cooperation of the moving clamp 4 and the fixed clamp 5, the anti-slip texture on their opposite sides is used to firmly lock the steel bar to prevent slippage. Then, the output end of the hydraulic cylinder 2 is controlled to perform an axial retraction action, which drives the clamping assembly to apply a tensile load to the steel bar. At the same time, the matching detection system begins to collect and record the tensile force value and stress change of the steel bar in real time.

[0102] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A material strength testing device for building engineering, comprising a base (1); Its features are: Two coaxially distributed hydraulic cylinders (2) are horizontally fixedly installed on the top surface of the base (1), and the output ends of the two hydraulic cylinders (2) are arranged opposite to each other. Each of the hydraulic cylinders (2) is provided with a clamping assembly at its output end; The clamping assembly includes a housing (3) fixedly installed on the output end of the hydraulic cylinder (2); the housing (3) has an insertion hole on the side wall away from the corresponding hydraulic cylinder (2); the housing (3) has a movable clamping plate (4) and a fixed clamping plate (5) that cooperate with each other, and the adjacent sides of the movable clamping plate (4) and the fixed clamping plate (5) are provided with anti-slip textures. The inner wall of the box (3) is provided with a limiting plate (6), and the limiting plate (6) and the insertion hole are symmetrically distributed on both sides of the fixed clamping plate (5); Furthermore, an installation ring (7) is movably embedded in the socket, and a first brush (8) is fixedly installed on the inner ring side surface of the installation ring (7). The housing (3) is provided with a drive mechanism for driving the installation ring (7) to rotate. It also includes a gas supply mechanism for providing high-pressure gas into the housing (3); Furthermore, both the fixed clamping plate (5) and the movable clamping plate (4) are provided with multiple mounting holes (9), and each mounting hole (9) is provided with a pressure-applying mechanism; The upper and lower end faces of the limiting plate (6) are fixedly equipped with a second brush (21). The second brush (21) is used to brush and clean the clamping surfaces of the fixed clamping plate (5) and the moving clamping plate (4) during the movement of the limiting plate (6). The housing (3) is provided with an elastic telescopic mechanism for supporting the limiting plate (6) and driving it to reset; wherein the elastic telescopic mechanism is configured to: hold the limiting plate (6) in the natural state on the side of the fixed clamping plate (5) close to the insertion hole, and allow the limiting plate (6) to retract and move away from the insertion hole when subjected to the pushing force of the reinforcing bar.

2. The strength testing equipment for building materials according to claim 1, characterized in that: The side wall of the box (3) is provided with a receiving cavity (10), and the insertion hole penetrates the side wall of the box (3) and passes through the receiving cavity (10) in the horizontal direction; the mounting ring (7) is rotatably embedded in the receiving cavity (10), and the central axis of the mounting ring (7) coincides with the central axis of the insertion hole; A gear (11) is rotatably installed in the cavity (10), and the outer circumferential wall of the mounting ring (7) is evenly provided with tooth grooves (12) that mesh with the gear (11) along the circumferential direction. Furthermore, a drive motor (13) with its output end fixedly connected to the shaft of the gear (11) is fixedly installed on the side wall of the housing (3).

3. The strength testing equipment for building materials according to claim 2, characterized in that: The pressurizing mechanism includes a top rod (14) that is vertically slidably installed in the mounting hole (9), and an elastic element (15) is installed between the top rod (14) and the corresponding mounting hole (9). The end of the push rod (14) away from the elastic member (15) is provided with a cone-shaped tooth with the tip pointing upwards.

4. The strength testing equipment for building materials according to claim 3, characterized in that: A support leg is fixedly installed on the inner bottom wall of the box (3), and the fixed clamp (5) is fixedly installed on the top of the support leg; A hydraulic rod (16) is vertically fixed on the inner top wall of the box (3), and the movable clamp (4) is fixedly installed on the output end of the hydraulic rod (16); The central axes of the moving clamp (4) and the fixed clamp (5) are both coincident with the axis of the hydraulic rod (16).

5. The strength testing equipment for building materials according to claim 4, characterized in that: The drive motor (13) is a dual-axis output motor, and the gear (11) is fixedly installed on the first output shaft of the dual-axis output motor; the air supply mechanism includes an air inlet opened on the side wall of the housing (3), and the air inlet and the socket are respectively set on the opposite side walls of the housing (3); A fan blade (17) is rotatably installed inside the air inlet, and the central shaft of the fan blade (17) is fixedly connected to the second output shaft of the dual-shaft output motor. A removable dust filter (18) is fixedly installed on the outside of the air inlet. The dust filter (18) is used to filter large dust particles in the air entering the housing (3).

6. The strength testing equipment for building materials according to claim 5, characterized in that: The movable clamp (4) is provided with a guide through hole; the box body (3) is provided with a vertically arranged guide rod (19), and the two ends of the guide rod (19) are respectively fixedly connected to the inner top wall and the inner bottom wall of the box body (3); The guide rod (19) slides through the guide hole to restrict the circumferential rotation of the moving clamp (4) during the movement process; A buffer spring (20) is fitted on the outer circumference of the guide rod (19), and the two ends of the buffer spring (20) abut against the upper surface of the moving clamp (4) and the inner top wall of the box (3).

7. The strength testing equipment for building materials according to claim 6, characterized in that: The top wall of the fixed clamping plate (5) and the bottom wall of the movable clamping plate (4) are both designed as V-shaped groove structures; The anti-slip texture adopts a one-way reverse sawtooth design, and the inclination angle of the sawtooth is designed to be opposite to the direction of the movement trend of the steel bar when it is under tension.

8. The strength testing equipment for building materials according to claim 1, characterized in that: The elastic telescopic mechanism includes a guide sleeve (22) that is horizontally fixed on the inner side wall of the box (3). The guide sleeve (22) and the insertion hole are located on opposite side walls of the box (3), and the central axis of the guide sleeve (22) coincides with the central axis of the insertion hole. The guide sleeve (22) has a telescopic cavity at one end near the insertion hole. A piston rod (23) is slidably installed in the telescopic cavity. A return spring (24) abuts against the piston rod (23) and the inner bottom wall of the telescopic cavity. The limiting plate (6) is fixedly installed at one end of the piston rod (23) that extends out of the guide sleeve (22).

9. The strength testing equipment for building materials according to claim 1, characterized in that: An auxiliary support roller mechanism is also provided between the box (3) and the base (1); The auxiliary support roller mechanism includes a bracket (25) installed at the bottom of the box (3). The bottom end of the bracket (25) is provided with an installation groove, and a load-bearing roller (26) that rolls and contacts the top surface of the base (1) is movably arranged in the installation groove. The load-bearing rollers (26) are used to share the weight of the cantilevered box (3) and the output end of the hydraulic cylinder (2).

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