A concrete quality detection device for construction engineering

Abstract

This invention belongs to the field of concrete testing technology, and specifically relates to a concrete quality testing device for building engineering. It includes a base, a gantry frame mounted on the base, a lifting drive unit installed within the gantry frame, and a lifting plate connected to the lifting drive unit. A centering clamping assembly is connected to the lifting plate via a tension sensor. A centering clamping assembly is also mounted on the base. The centering clamping assembly includes support seats mounted on the tension sensor and the base, and multiple telescopic centering sleeves mounted on the support seats and interlocking with each other. The movable clamping assembly includes a movable disc mounted outside the outermost centering sleeve, multiple sets of power components mounted on the movable disc, a movable strip connected to each set of power components, and a clamping plate mounted at the end of the movable strip. This invention enables rapid centering and clamping of specimens of different sizes, thereby improving the accuracy of concrete tensile strength quality testing.

Description

Technical Field

[0001] This invention belongs to the field of concrete testing technology, and in particular relates to a concrete quality testing device for building engineering. Background Technology

[0002] In construction engineering, most of the quality testing of concrete involves strength testing. However, the tensile strength of concrete is much lower than its compressive strength. It is the core indicator for controlling concrete cracking, load-bearing capacity, durability, and construction quality. It is also a necessary basic data for structural design, mix optimization, project acceptance, and scientific research. Therefore, it is essential to test the tensile strength of concrete. Commonly used methods for testing the tensile strength of concrete include the indirect method (split tensile strength) and the direct method (axial tensile strength). The axial tensile strength test involves applying axial tensile force to a prism specimen and directly determining the ultimate tensile strength. It can simultaneously determine the ultimate tensile value and the tensile modulus of elasticity. Existing instruments for testing the tensile strength of concrete specimens require the fabrication of a concrete specimen, with pre-embedded tensile reinforcement bars / connectors at both ends. If the pre-embedded bars are not perfectly centered, even a slight deviation can lead to inherent eccentricity. Insufficient anchorage length or weak grip can result in bar pull-out or end-crack, rendering the test invalid. Furthermore, directly clamping the concrete specimen onto the testing equipment's fixtures not only requires consideration of the fixture's firmness but also makes it difficult to clamp and test concrete specimens of different diameters, thus affecting the versatility and practicality of the testing equipment for testing the tensile strength of concrete specimens of different sizes. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to a concrete quality testing device for building engineering, comprising a base, a portal frame mounted on the base, a lifting drive unit mounted inside the portal frame, and a lifting plate connected to the lifting drive unit. The lifting plate is connected to a centering clamping assembly via a tension sensor, and the base is also equipped with a centering clamping assembly. The centering clamping assembly includes a support base respectively mounted on the tension sensor and the base, and a multi-section centering sleeve mounted on the support base that is interconnected and retractable. Among them, the centering sleeve located on the outermost ring is fixedly connected to the support base, the centering sleeve located on the innermost ring is connected to the lifting connection assembly installed in the support base, and the centering sleeve located in the middle part is connected in sequence. The support base is equipped with a movable clamping assembly, which includes a movable disk installed outside the outermost centering sleeve, multiple sets of power components installed on the movable disk, a movable strip connected to each set of power components, and a clamping plate installed at the end of the movable strip. The centering sleeve of the multi-section has multiple avoidance notches, and the upper groove of the avoidance notch is open while the lower groove is closed, so that the moving strip can move within the avoidance notch.

[0004] Furthermore, the lifting connection assembly includes a lifting groove formed in the support base, a first lead screw installed in the lifting groove, and a limiting ring fixed to the top of the first lead screw. The first lead screw is connected to the bottom of the centering sleeve located in the innermost ring through a ball nut, and the limiting ring is located above the bottom of the centering sleeve. Each of the centering sleeves has a long slot, and an insulating strip is installed in each slot. An electromagnet is embedded in the insulating strip installed on the outermost centering sleeve, while a non-contact metal strip and an electromagnet are installed in the insulating strip installed on the middle centering sleeve. A metal strip is also installed on the insulating strip installed on the innermost centering sleeve, and the metal strip is in close contact with the aligned electromagnet.

[0005] Furthermore, the power assembly includes a movable long slot radially formed on the movable disk, a support block mounted on the lower surface of the movable disk and located at the movable long slot, a second lead screw mounted rotatably on the support block, and a connecting block sleeved on the second lead screw via a ball nut, wherein the connecting block passes through the movable long slot and is connected to the movable long strip.

[0006] Furthermore, the movable clamping assembly also includes an electric push rod vertically fixed on the support base, and the output rod end of the electric push rod is connected to the movable disk. A metal block is insulatedly installed on the movable strip, and the metal block is in contact with the electromagnet.

[0007] Furthermore, a protective cover is fixed on the support base, and the protective cover is located outside the movable clamping assembly. A protective plate connected to the centering sleeve fixed to the outermost ring is installed at the upper opening of the protective cover.

[0008] Furthermore, the movable clamping assembly also includes a tail protrusion mounted on the tail of the movable strip, a support rod mounted vertically on the tail protrusion, a connecting protrusion mounted on the top of the support rod, and a sealing block connected to the connecting protrusion. The width of the sealing block matches the width of the slot that avoids the notch, and the end of the sealing block extending into the centering sleeve is located outside the clamping plate.

[0009] Furthermore, the support rod is movably sleeved on the connecting protrusion, and an elastic element connects the connecting protrusion and the tail protrusion. The top of the support rod extends out of the top surface of the connecting protrusion through the cooperation of a nut and a screw. A U-shaped bracket is fixed on the inner ring surface of the protective cover, and the two side rods of the U-shaped bracket are movably inserted into the support groove radially opened at the tail of the sealing block.

[0010] Furthermore, the clamping plate is connected to the movable strip in a detachable manner, and the height of the clamping plate is greater than the thickness of the movable strip.

[0011] The present invention has the following beneficial effects: This invention utilizes multiple centering sleeves that are sequentially nested and capable of vertical movement to adapt to test specimens of different sizes. These sleeves also ensure vertical centering of the clamped specimens. Furthermore, the combination of multiple radially movable strips in a circumferential array with the clamping plate enables automatic positioning and clamping of specimens inserted into different centering sleeves. This allows the testing device of this invention to perform rapid and accurate tensile testing on specimens of different sizes without requiring changes to the clamping body, thus improving the versatility and efficiency of the equipment.

[0012] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the clamping and testing of a specimen according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the detection device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the centering clamping assembly according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the protective cover after disassembly according to an embodiment of the present invention; Figure 5 This is an exploded view of the assembly of the support base and the centering sleeve according to an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the adjustment of multiple centering sleeves according to an embodiment of the present invention; Figure 7 This is a cross-sectional view of the centering sleeve according to an embodiment of the present invention; Figure 8 This is a diagram showing the cooperative state of the movable strip and the blocking block according to an embodiment of the present invention.

[0015] In the diagram: 1. Base; 2. Gantry frame; 3. Lifting plate; 4. Centering clamping assembly; 41. Support seat; 42. Centering sleeve; 421. Avoidance notch; 43. First lead screw component; 44. Limiting ring; 45. Insulating strip; 46. Electromagnet; 47. Metal strip; 5. Moving clamping assembly; 51. Moving disk; 511. Moving slot; 52. Moving strip; 521. Metal block; 522. Tail protrusion; 53. Clamping plate; 54. Support block; 55. Second lead screw component; 56. Connecting block; 57. Electric push rod; 58. Support rod; 59. Sealing block; 591. Connecting protrusion; 592. Support slide; 593. Elastic component; 6. Protective cover; 61. Protective plate; 62. U-shaped bracket. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0018] As mentioned in the background section, the fixtures or clamping tools of the relevant tensile strength testing equipment are basically combinations of multiple jaws. The specimen to be tested is directly placed into the jaws to clamp and fix the specimen. Obviously, it is impossible to adjust the centering and prevent lateral tilting of the specimen during clamping. This can easily lead to the accumulation of errors such as eccentricity, stress concentration, and manual operation in the clamped specimen, resulting in a strength fluctuation of 15% to 30% in the same group of specimens. Moreover, it cannot be adapted to the clamping and tensile strength testing of specimens of different sizes.

[0019] Therefore, there is an urgent need to provide a method that can center and prevent lateral tilting of the specimen to be clamped, and can also adjust the size of the centering sleeve 42 according to the size of the specimen to be clamped, so as to facilitate the rapid centering and clamping of specimens of different sizes, thereby improving the accuracy of concrete tensile strength quality testing. Based on this, please refer to Figures 1-8 As shown, the present invention is a concrete quality testing device for building engineering, including a base 1, a portal frame 2 installed on the base 1, a lifting drive unit installed in the portal frame 2, and a lifting plate 3 connected to the lifting drive unit. The lifting plate 3 is connected to a centering clamping component 4 through a tension sensor, and the base 1 is also equipped with a centering clamping component 4. The centering clamping assembly 4 includes a support base 41 respectively mounted on the tension sensor and the base 1, and a multi-section centering sleeve 42 mounted on the support base 41 and sleeved together and capable of telescopic movement. Among them, the centering sleeve 42 located on the outermost ring is fixedly connected to the support base 41, the centering sleeve 42 located on the innermost ring is connected to the lifting connection assembly installed in the support base 41, and the centering sleeve 42 located in the middle part is connected in sequence. The support base 41 is equipped with a movable clamping assembly 5, which includes a movable disk 51 installed outside the outermost centering sleeve 42, multiple sets of power components installed on the movable disk 51, a movable strip 52 connected to each set of power components, and a clamping plate 53 installed at the end of the movable strip 52. The centering sleeve 42 of the multi-section has multiple avoidance notches 421, and the upper groove of the avoidance notch 421 is open and the lower groove is closed, so that the moving strip 52 can move within the avoidance notch 421. In a preferred embodiment, the lifting drive unit is preferably either a ball screw pair with a motor or a linear motor. The centering clamping assembly 4 installed on the lifting plate 3 and the base 1 have the same structure and are arranged coaxially. The lifting plate 3 is equipped with sealing louvers on the plate body inside the portal frame 2. Before use, the detection device will perform coaxiality detection on the upper and lower sets of centering clamping assemblies 4. The number of multi-section centering sleeves 42 is preferably three sets. Taking the three sets in the figure as an example, the centering sleeve 42 fixedly connected to the support base 41 is the outermost centering sleeve 42, the centering sleeve 42 connected to the lifting connection assembly is the innermost centering sleeve 42, and the one in between is the middle centering sleeve 42. Multiple avoidance notches 421 are opened in a circumferential array, preferably four. Therefore, the corresponding power assembly, moving strip 52 and clamping plate 53 are also four sets. The surface of the clamping plate 53 that contacts the specimen to be tested is roughened. The specific use of the detection device in this solution is as follows: First, when it is necessary to test the tensile strength of the formed concrete specimen (hereinafter referred to as the specimen), the coaxiality of the upper and lower sets of centering clamping components 4 is first tested to ensure that the upper and lower sets of centering clamping components 4 are on the same axis. Since the three interlocking centering sleeves 42 are at the same center, it is not necessary to test the coaxiality of the three interlocking centering sleeves 42. Then, according to the length of the specimen, the lifting drive unit is activated to drive the upper centering clamping components 4 to descend a certain distance through the lifting plate 3, so that the distance between the upper and lower sets of centering clamping components 4 is less than the length of the specimen. Second, when a test piece needs to be inspected, the alignment sleeve 42 should be adjusted according to the diameter of the test piece to determine whether it needs to be retracted into the support base 41. For example, if the diameter of the test piece is smaller than the inner diameter of the outermost alignment sleeve 42 but larger than the inner diameter of the middle alignment sleeve 42, then both the inner and middle alignment sleeves 42 need to be retracted into the support base 41 simultaneously. In this case, the lifting connection assembly needs to be controlled via the control panel on one side of the portal frame 2 to ensure that the inner and middle alignment sleeves 42 are retracted into the support base 41. The centering sleeves 42 are connected to each other, and then the two connected centering sleeves 42 are driven to descend inside the outer ring centering sleeve 42, while avoiding the upper groove of the notch 421 being in an open state, so that the moving strip 52 will not interfere with the vertical descent of the centering sleeve 42, thereby allowing the top of the two connected centering sleeves 42 to descend to a position lower than the clamping plate 53. At this time, the inner diameter of the multi-section interconnected centering sleeves 42 is adapted and adjusted. At the same time, it is necessary to adjust the retraction length of the connected centering sleeves 42 in the upper and lower sets of centering clamping assemblies 4 to be the same. Third, insert both ends of the test specimen into the upper and lower adjusted outer ring centering sleeves 42 respectively, and make the outer ring surface of the test specimen close to the inner wall of the clamping plate 53, while the two ends of the test specimen abut against the end face of the retracted centering sleeve 42, so that the length of the test specimen inserted into the upper and lower centering sleeves 42 is the same. At this time, the upper and lower symmetrical centering sleeves 42 can not only center the test specimen to prevent it from deviating, but also provide gravity support for the inserted test specimen. Then, make the multiple sets of power components on the moving disk 51 work synchronously, so that they drive multiple moving strips 52 to move toward the center of the centering sleeve 42, so that the clamping plates 53 of several circumferential arrays can clamp and fix the inserted test specimen. Fourth, close the protective cover (not shown in the figure) on the gantry frame 2, and then operate the control panel to make the lifting drive unit drive the lifting plate 3 to move upward continuously and uniformly, with a loading rate of 0.01~0.02MPa / s. At this time, the centering sleeve 42 above moves upward at a uniform speed with the lifting plate and loads the specimen uniformly until the specimen breaks. Record the failure load F (N), and then take the arithmetic mean of 3 valid specimens as the representative value of the group. If the difference between a single value and the median value is >15%, the value is discarded, and the average of the remaining two values ​​is taken. If the difference between both values ​​and the median value is >15%, the result of this group is invalid.

[0020] In this embodiment, the lifting connection assembly includes a lifting groove formed in the support base 41, a first lead screw 43 installed in the lifting groove, and a limiting ring 44 fixed to the top of the first lead screw 43. The first lead screw 43 is connected to the bottom of the centering sleeve 42 located in the innermost ring through a ball nut, and the limiting ring 44 is located above the bottom of the centering sleeve 42. Each of the centering sleeves 42 has a long slot, and an insulating strip 45 is installed in each long slot. An electromagnet 46 is embedded in the insulating strip 45 installed on the outermost centering sleeve 42. A non-contact metal strip 47 and an electromagnet 46 are installed in the insulating strip 45 installed on the centering sleeve 42 in the middle. A metal strip 47 is also installed on the insulating strip 45 installed on the innermost centering sleeve 42, and the metal strip 47 is in close contact with the aligned electromagnet 46. In a preferred embodiment, the elongated grooves are formed on both side walls that avoid the notch 421, facilitating the installation of the insulating strip 45 and also facilitating the contact between the metal block 521 on the elongated strip 52 and the electromagnet 46. The diameter of the lifting groove matches the inner diameter of the outermost centering sleeve 42, allowing the middle centering sleeve 42 to be accurately retracted into the lifting groove. Specifically, the contact between the metal strip 47 and the strip-shaped electromagnet 46 is as follows: the electromagnet 46 mounted on the outermost centering sleeve 42 contacts the metal strip 47 embedded in the insulating strip 45 on the outer surface of the middle centering sleeve 42, while the electromagnet 46 embedded in the insulating strip 45 on the inner surface of the middle centering sleeve 42 contacts the metal strip 47 embedded in the insulating strip 45 on the outer surface of the innermost centering sleeve 42. Therefore, the following can be achieved: When only the innermost centering sleeve 42 needs to descend vertically, the electromagnet 46 on the outermost centering sleeve 42 is energized, giving it magnetic attraction to hold the middle centering sleeve 42 in place. Conversely, the electromagnet 46 on the middle centering sleeve 42 is de-energized, causing it to disengage from the magnetic attraction of the innermost centering sleeve 42. Then, the self-locking motor fixed at the bottom of the lifting groove is activated. The output shaft of the motor drives the first lead screw 43 connected to it to rotate, which in turn drives the innermost centering sleeve 42 back into the lifting groove through the ball nut. This facilitates the retraction and adjustment of multiple interlocking centering sleeves 42. When the middle and innermost centering sleeves 42 need to be lowered and retracted, the electromagnet 46 on the outermost centering sleeve 42 needs to be de-energized. Since the middle and innermost centering sleeves 42 are fixed by the electromagnet 46 and the metal strip 47, the rotation of the first lead screw 43 will drive the interconnected centering sleeves 42 to be retracted into the lifting groove synchronously through the ball nut. The motor fixed in the lifting groove can drive the first lead screw 43 to rotate in the reverse direction, so that the centering sleeve 42 retracted in the lifting groove can extend again. Due to the setting of the limiting ring 44, the upper sleeve opening of the extended centering sleeve 42 can be flush with the opening of the outermost fixed centering sleeve 42, which makes it easier to accurately center and clamp specimens of different sizes. It should be noted that whether the innermost centering sleeve 42 is driven to retract into the lifting groove individually, or at least two connected centering sleeves 42 are driven to retract into the lifting groove simultaneously, the centering sleeve 42 that was retracted last time must first be extended to be flush with the outermost centering sleeve 42 before the next adjustment is performed.

[0021] In this embodiment, the power assembly includes a movable long groove 511 radially formed on the movable disk 51, a support block 54 mounted on the lower surface of the movable disk 51 and located at the movable long groove 511, a second lead screw 55 rotatably mounted on the support block 54, and a connecting block 56 sleeved on the second lead screw 55 by a ball nut, wherein the connecting block 56 passes through the movable long groove 511 and is connected to the movable long strip 52. As a preferred embodiment, four movable long slots 511 are preferably arranged in a circular array and through the movable disk 51. A motor with a self-locking function is fixedly installed on the support block 54 near the outer ring surface of the movable disk 51. The motor is connected to the second lead screw 55, and the length of the second lead screw 55 is greater than the length of the movable long strip 52. Furthermore, through the control panel of the detection device, four sets of motors can be controlled to work synchronously. Then, the second lead screw 55 will drive the connecting block 56 to slide in the moving long groove 511 through the ball nut. Then, the connecting block 56 will drive the moving long strip 52 to slide radially on the centering sleeve 42, so that multiple sets of clamping plates 53 can clamp and fix the specimen synchronously and accurately. When multiple connecting blocks 56 move synchronously toward the outer ring surface of the moving disk 51, multiple moving strips 52 will drive multiple clamping plates 53 forming a ring to move away from each other and expand, thereby facilitating accurate and rapid clamping of larger specimens.

[0022] In this embodiment, the movable clamping assembly 5 further includes an electric push rod 57 vertically fixed on the support base 41, and the output rod end of the electric push rod 57 is connected to the movable disk 51. A metal block 521 is insulatedly installed on the movable strip 52, and the metal block 521 is in contact with the electromagnet 46. In a preferred embodiment, the metal block 521 is insulatedly installed on the surface of the movable strip 52 that is in contact with the side wall of the notch 421, and the length of the metal block 521 is matched with the length of the movable strip 52, so that when the movable strip 52 moves radially, the metal block 521 can always be in contact with the electromagnet 46, and the metal block 521 is in contact with the electromagnet 46 that is exposed inside the insulating strip 45 on the outermost centering sleeve 42. The electric push rod 57 is preferably at least two sets and arranged in a circumferential manner. In order to provide a precise and stable clamping force for specimens of different lengths and to prevent the specimens from detaching from the centering sleeve 42 during tensile testing, when it is necessary to clamp and fix short-length specimens, it is necessary to first de-energize the electromagnet 46 on the outermost centering sleeve 42 to release it from the adsorption and fixation of the metal block 521, while the middle centering sleeve 42 continues to be adsorbed and fixed with the innermost centering sleeve 42, so as to achieve gravity support for the middle centering sleeve 42. Then, the output rods of multiple electric push rods 57 are extended to drive the moving disk 51 to rise along the outer ring surface of the centering sleeve 42, thereby enabling the moving strip 52 and the clamping plate 53 to rise a certain distance within the centering sleeve 42. This facilitates the adjustment of the height of the clamping plate 53 within the centering sleeve 42, enabling the accurate application of clamping force even for specimens of small length. Once the height of the multiple clamping plates 53 has been adjusted, if it is necessary to retract the centering sleeve 42, the height of the opening of the retracted centering sleeve 42 can be controlled to be lower than the height of the adjusted clamping plates 53. This allows the retracted centering sleeve 42 to provide end contact support for small-sized specimens without interfering with the accurate application of clamping force by the multiple clamping plates 53 after height adjustment to clamp and fix the small-sized specimens. It should be noted that when the centering sleeve 42 is retracted and adjusted, although the electromagnet 46 on the outermost centering sleeve 42 is de-energized, the moving disk 51 is still supported by gravity through the electric push rod 57. Therefore, it will not provide stable support for the clamping plate 53 after the height adjustment. When the clamping plate 53 moves to clamp and fix the inserted specimen, the electromagnet 46 on the outermost centering sleeve 42 is de-energized, causing it to disengage from the moving strip 52, allowing the multiple clamping plates 53 to stably clamp and fix the specimen. Once the specimen is clamped and fixed, the electromagnet 46 on the outermost centering sleeve 42 is energized, enabling it to both adhere to and fix the middle centering sleeve 42 and the moving strip 52, thus allowing the lifting drive unit to apply load to the specimen. The applied load will act on the outermost fixed centering sleeve 42 through the clamping plate 53 and the adsorbed moving strip 52. This can effectively prevent the load force from being directly applied to the electric push rod 57 through the clamping plate 53, moving strip 52 and other components when the lifting drive unit applies a load. This would require the electric push rod 57 to be continuously powered and to pull and fix the moving disk 51, which would not only affect the service life of the electric push rod 57, but also affect the accuracy and safety of the tensile strength test of the specimen.

[0023] In this embodiment, a protective cover 6 is fixed on the support base 41, and the protective cover 6 is located outside the movable clamping assembly 5. A protective plate 61 connected to the centering sleeve 42 fixed to the outermost ring is installed at the upper opening of the protective cover 6. As a preferred embodiment, the installation of the protective cover 6 and the multiple segmented protective plates 61 can protect structural components such as the centering clamping assembly 4 and the moving clamping assembly 5, preventing debris from the broken specimen from falling into the protective cover 6 and causing unnecessary damage to the moving clamping assembly 5 and other components.

[0024] In this embodiment, the movable clamping assembly 5 further includes a tail protrusion 522 mounted on the tail of the movable strip 52, a support rod 58 mounted vertically on the tail protrusion 522, a connecting protrusion 591 mounted on the top of the support rod 58, and a sealing block 59 connected to the connecting protrusion 591. The width of the sealing block 59 matches the width of the slot that avoids the notch 421, and the end of the sealing block 59 extending into the centering sleeve 42 is located outside the clamping plate 53. Further specified, the support rod 58 is movably sleeved on the connecting protrusion 591, and an elastic element 593 is connected between the connecting protrusion 591 and the tail protrusion 522. The top of the support rod 58 extends out of the top surface of the connecting protrusion 591 through the cooperation of a nut and a screw. The inner ring surface of the protective cover 6 is fixedly provided with a U-shaped bracket 62, and the two side rods of the U-shaped bracket 62 are movably inserted into the support groove 592 radially opened at the tail of the sealing block 59. As a preferred embodiment, in order to prevent broken debris from falling into the avoidance notch 421 and thus affecting the radial and vertical sliding movement of the moving strip 52; Therefore, when the moving strip 52 drives the clamping plate 53 to move radially, the moving strip 52 will drive the sealing block 59 to slide radially at the upper slot opening that avoids the notch 421 through the tail protrusion 522, the vertical support rod 58 and the connecting protrusion 591. In this way, when the sealing block 59 blocks the upper slot opening that avoids the notch 421, the sliding sealing block 59 will not interfere with the normal retraction movement of the centering sleeve 42. In order to avoid the sealing block 59 from moving synchronously when the moving strip 52 moves up and down, which would affect the sealing effect of the sealing block 59 on the groove of the notch 421; This solution further specifies that a spring-like elastic element 593 is sleeved on the outside of the support rod 58, with its two ends connected to the tail protrusion 522 and the connecting protrusion 591 respectively. The support rod 58 and the connecting protrusion 591 are slidably connected. The sealing block 59, through the cooperation of the U-shaped bracket 62 and the support groove 592, prevents vertical movement along its axis. Therefore, when multiple moving strips 52 drive multiple clamping plates 53 to rise, the support rod 58 will move upward along the through hole in the connecting protrusion 591. At the same time, the nut will move synchronously, and the elastic element 593... 93 will be compressed, and at this time the sealing block 59 will always be at the upper groove of the notch 421 to achieve the sealing treatment of the notch 421. When the moving strip 52 moves radially, the supporting rod 58 will drive the sealing block 59 to move radially synchronously through the connecting protrusion 591. At this time, the U-shaped bracket 62 in the fixed state will be in a stationary state to provide gravity support and guide the movement of the sealing block 59, so that the sealing block 59 can move radially synchronously with the clamping plate 53, and avoid the sealing block 59 being unable to move radially, which would affect the stable clamping of specimens of different diameters by the adjusted multiple sets of clamping plates 53. An elastic sealing membrane is installed at the upper groove of the U-shaped bracket 62, and the elastic sealing membrane is connected to the connecting protrusion 591 and the bottom of the groove of the U-shaped bracket 62 to seal the groove of the U-shaped bracket 62.

[0025] In this embodiment, the clamping plate 53 is detachably connected to the movable strip 52, and the height of the clamping plate 53 is greater than the thickness of the movable strip 52. The clamping plate 53 uses a back protrusion and a recessed groove on the movable strip 52 for engagement, and then achieves a detachable connection with screws. This not only facilitates the disassembly and replacement of the clamping plate 53 after long-term use, but also allows for the replacement of clamping plates 53 of different sizes and shapes, such as curved plates, prismatic plates, etc., to achieve the processing of specimens of different shapes. Stable and safe clamping operation; Since the clamping plate 53 has a certain thickness inside the centering sleeve 42, when the clamping plate 53 clamps the specimen, there will be a certain gap between the outer ring surface of the specimen and the inner wall of the centering sleeve 42. In order to further prevent the residue of the tensile fractured concrete specimen from falling into the centering sleeve 42, the radial width of the sealing strip can be selected according to the thickness of the clamping plate 53 before the specimen is clamped, and the sealing strip can be installed between the clamped specimen and the inner ring surface of the centering sleeve 42 to achieve sealing treatment.

[0026] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0027] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A concrete quality testing device for construction engineering, comprising a base, a gantry frame mounted on the base, a lifting drive unit installed within the gantry frame, and a lifting plate connected to the lifting drive unit, characterized in that, The lifting plate is connected to a centering clamping assembly via a tension sensor, and the base is also equipped with a centering clamping assembly. The centering clamping assembly includes a support base respectively mounted on the tension sensor and the base, and a multi-section centering sleeve mounted on the support base that is interconnected and retractable. Among them, the centering sleeve located on the outermost ring is fixedly connected to the support base, the centering sleeve located on the innermost ring is connected to the lifting connection assembly installed in the support base, and the centering sleeve located in the middle part is connected in sequence. The support base is equipped with a movable clamping assembly, which includes a movable disk installed outside the outermost centering sleeve, multiple sets of power components installed on the movable disk, a movable strip connected to each set of power components, and a clamping plate installed at the end of the movable strip. The centering sleeve of the multi-section has multiple avoidance notches, and the upper groove of the avoidance notch is open while the lower groove is closed, so that the moving strip can move within the avoidance notch.

2. The concrete quality testing device for building engineering according to claim 1, characterized in that, The lifting connection assembly includes a lifting groove formed in the support base, a first lead screw installed in the lifting groove, and a limiting ring fixed to the top of the first lead screw. The first lead screw is connected to the bottom of the centering sleeve located in the innermost ring through a ball nut, and the limiting ring is located above the bottom of the centering sleeve. Each of the centering sleeves has a long slot, and an insulating strip is installed in each slot. An electromagnet is embedded in the insulating strip installed on the outermost centering sleeve, while a non-contact metal strip and an electromagnet are installed in the insulating strip installed on the middle centering sleeve. A metal strip is also installed on the insulating strip installed on the innermost centering sleeve, and the metal strip is in close contact with the aligned electromagnet.

3. The concrete quality testing device for building engineering according to claim 1, characterized in that, The power assembly includes a radially formed long groove on the movable disk, a support block mounted on the lower surface of the movable disk and located at the long groove, a second lead screw mounted rotatably on the support block, and a connecting block sleeved on the second lead screw via a ball nut, wherein the connecting block passes through the long groove and is connected to the long groove.

4. The concrete quality testing device for building engineering according to claim 3, characterized in that, The movable clamping assembly also includes an electric push rod that is vertically fixed on the support base. The output rod end of the electric push rod is connected to the movable disk. A metal block is insulated and installed on the movable strip, and the metal block is in contact with the electromagnet.

5. A concrete quality testing device for building engineering according to claim 1, characterized in that, A protective cover is fixed on the support base, and the protective cover is located outside the movable clamping assembly. A protective plate connected to the centering sleeve fixed to the outermost ring is installed at the upper opening of the protective cover.

6. A concrete quality testing device for building engineering according to claim 5, characterized in that, The movable clamping assembly also includes a tail protrusion mounted on the tail of the movable strip, a support rod mounted vertically on the tail protrusion, a connecting protrusion mounted on the top of the support rod, and a sealing block connected to the connecting protrusion. The width of the sealing block matches the width of the slot that avoids the notch, and the end of the sealing block extending into the centering sleeve is located outside the clamping plate.

7. A concrete quality testing device for building engineering according to claim 6, characterized in that, The support rod is movably sleeved on the connecting protrusion, and an elastic element connects the connecting protrusion and the tail protrusion. The top of the support rod extends out of the top surface of the connecting protrusion through the cooperation of a nut and a screw. A U-shaped bracket is fixed on the inner ring surface of the protective cover, and the two side rods of the U-shaped bracket are movably inserted into the support groove radially opened at the tail of the sealing block.

8. A concrete quality testing device for building engineering according to claim 1, characterized in that, The clamping plate is connected to the movable strip in a detachable manner, and the height of the clamping plate is greater than the thickness of the movable strip.

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