Self-tapping screw pull-out test device

Abstract

The invention relates to the technical field of building structure foundation test equipment, and discloses a self-tapping screw pull-out test device which comprises an upper clamp, a lower clamp and a pressure equalizing assembly. The upper clamp is of a split adjustable clamping structure and is matched with clamping cavities of self-tapping screws with different outer diameter specifications, stable clamping is achieved, a modularized base material mounting platform of the lower clamp is combined with a sliding groove structure and a positioning pin, the vertical height and the horizontal position of a base material can be adjusted in cooperation with adjustable bolts of the vertical anchor rod and the transverse anchor rod, and the clamping effect is good. A concave arc-shaped elastic pad and a rhombic bulge of the pressure equalizing assembly not only enhance contact friction force and prevent slipping, but also disperse stress through elastic deformation to avoid local pressure loss of a base material, so that the service life of the screw is prolonged, and the service life of the screw is prolonged. Therefore, the clamping adaptability, the centering accuracy, the stress uniformity and the displacement measurement accuracy can be improved, and the device is suitable for testing of various base materials and screws of different specifications, so that the authenticity and reliability of test data are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building structure foundation test equipment, and particularly relates to a self-tapping screw pull-out test device. BACKGROUND

[0002] The self-tapping screw pull-out test device is a special mechanical property detection equipment, vertical tension is applied through a servo motor or a hydraulic system, a special clamp is matched to fix a test piece and a self-tapping screw, tension values, displacement deformation and other data are collected in real time, and a force-displacement curve is generated, the maximum pull-out force when the screw is pulled out or the base material is damaged is accurately measured, and the core is used for evaluating the connection strength and stability of the self-tapping screw in the fields of building engineering, mechanical manufacturing, aerospace and the like.

[0003] In the self-tapping screw pull-out performance test, the clamping adaptability, centering accuracy and stress transmission uniformity of the test device directly determine the reliability of the test data, however, the clamps of the existing test device are mostly fixed specifications, cannot adapt to self-tapping screws of different specifications and different base materials, and centering deviation is prone to occur during clamping, so that the pull-out force is transmitted along a non-axis direction, screw abnormal fracture or test data distortion is caused, meanwhile, the clamping interface is mostly rigid contact, and local compression damage of the base material or slipping during the pull-out process is prone to occur, further affecting the test accuracy, and thus the existing device is difficult to meet the test requirements of screws of various specifications and different base materials, thereby affecting the authenticity and repeatability of the test results. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a self-tapping screw pull-out test device, which solves the problem that the conventional self-tapping screw pull-out test device is difficult to meet the test requirements of screws of various specifications and different base materials, thereby affecting the authenticity and repeatability of the test results.

[0005] The present application provides a self-tapping screw pull-out test device, which comprises: The upper clamp adopts a split type adjustable clamping structure and is composed of at least two clamping blocks, two clamping blocks are arranged below the upper clamp, and semicircular grooves are formed on the opposite surfaces of the two clamping blocks, and a clamping cavity is formed when the two semicircular grooves are folded, and a displacement test point is welded on one side edge of one of the clamping blocks, and the displacement test point is correspondingly arranged with a probe of a micrometer instrument; The lower clamp is coaxially arranged above and below the upper clamp, vertical anchor rods, horizontal anchor rods and a modular base material mounting platform are arranged on the lower clamp, adjustable bolts are arranged on the vertical anchor rods and the horizontal anchor rods, the modular base material mounting platform is connected to the bottom of the lower clamp through a sliding groove structure and a positioning pin, a micrometer instrument is fixedly connected to one side of the lower clamp through a magnetic support, and the probe of the micrometer instrument corresponds to the displacement test point of the upper clamp; The pressure equalizing assembly is arranged on the inner side of the lower clamp, and comprises a pressure equalizing plate, wherein the lower surface of the pressure equalizing plate is bonded with an elastic pad, the cross section of the elastic pad is in the shape of a concave circular arc, one side of the elastic pad is integrally formed with a plurality of protrusions, and the pressure equalizing plate and the elastic pad are provided with a relief hole, and the relief hole is coaxially arranged with the clamping cavity.

[0006] Preferably, the protrusions are in the shape of a rhombus, and a plurality of the protrusions are arranged in an array.

[0007] Preferably, the upper clamp and the lower clamp are both provided with a connecting hole diameter matched with a testing machine, the upper end of the upper clamp is provided with a strip-shaped sliding hole on both sides, the strip-shaped sliding hole is provided with a sliding screw, one end of the sliding screw is connected with a nut, and the other end of the sliding screw is movably penetrated through the strip-shaped sliding hole and fixedly connected with the clamping block.

[0008] Preferably, the clamping cavity is internally provided with a self-tapping screw, the self-tapping screw is sleeved with a gasket, and the head of the self-tapping screw is arranged in the interior of the clamping cavity.

[0009] Preferably, the modular substrate mounting platform is provided with a substrate, the substrate is arranged on the inner side of the lower clamp, and the rod of the self-tapping screw is penetrated through the clamping cavity, the pressure equalizing plate and the elastic pad and extends into the interior of the substrate.

[0010] Preferably, the upper end of the lower clamp is internally provided with a groove, and the pressure equalizing plate is mounted in the interior of the groove through a plurality of uniformly distributed general screws.

[0011] Preferably, the connecting part of the upper clamp and the testing machine is provided with an adjustable elastic compensation assembly, and the adjustable elastic compensation assembly comprises a spring gasket and a strain sensing unit.

[0012] Preferably, a signal acquisition module is arranged between the micrometer and the testing machine control system.

[0013] Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages: The self-tapping screw pull-out test device provided by the embodiment of the present application is characterized in that the upper clamp is provided with an openable adjustable clamping structure, so that the semicircular grooves of the two clamping blocks can be folded to form a clamping cavity suitable for different outer diameter specifications of the self-tapping screw, and flexible and stable clamping is achieved; the modular substrate mounting platform of the lower clamp is combined with the sliding groove structure and the positioning pin, and cooperates with the adjustable bolts of the vertical and horizontal anchor rods, so that the height and horizontal position of the substrate can be adjusted, the screw axis and the clamping cavity are coaxially centered, the stress deviation in the pulling process is avoided, the inner concave arc-shaped elastic pad and the rhombic protrusion of the pressure equalizing assembly not only enhance the contact friction force to prevent slipping, but also disperse stress through elastic deformation to avoid local damage to the substrate, the displacement test point of the edge of the clamping block is accurately contacted with the micrometer instrument, and the small displacement change is captured in real time, so that the clamping adaptability, centering accuracy, stress uniformity and displacement measurement accuracy are improved, the operation is simple, the cost is controllable, a complex electric control system is not needed, a variety of substrates and different specifications of screws can be tested, the problems of narrow adaptation range, low centering accuracy and easy damage of the substrate of the traditional device are solved, and the authenticity and reliability of the test data are greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A schematic diagram of the overall structure of the self-tapping screw pull-out test device provided by the embodiment of the present application is shown in the figure. Figure 2 A schematic diagram of the partial structure of the self-tapping screw pull-out test device provided by the embodiment of the present application is shown in the figure. Figure 3 An enlarged view of the middle A provided by the embodiment of the present application is shown in the figure. Figure 2 Figure 4 A schematic diagram of the lower clamp structure of the self-tapping screw pull-out test device provided by the embodiment of the present application is shown in the figure. Figure 5 A schematic diagram of the upper clamp structure of the self-tapping screw pull-out test device provided by the embodiment of the present application is shown in the figure.

[0015] Explanation of reference signs: 1, micrometer instrument; 2, upper clamp; 21, clamping block; 22, clamping cavity; 23, displacement test point; 24, connecting hole diameter; 25, strip-shaped sliding hole; 26, sliding screw; 3, self-tapping screw; 31, gasket; 4, lower clamp; 41, vertical anchor rod; 42, horizontal anchor rod; 43, modular substrate mounting platform; 5, substrate; 6, pressure equalizing assembly; 61, pressure equalizing plate; 62, elastic pad; 63, protrusion; 64, clearance hole; 7, groove. DETAILED DESCRIPTION

[0016] One specific embodiment of the present application will be described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present application is not limited by the specific embodiment. ​

[0017] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the technical solutions of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0018] The present application will be described below through several specific embodiments. In order to keep the following description of the embodiments of the present application clear and concise, the detailed description of known functions and known components can be omitted. When any component of the embodiments of the present application appears in more than one figure, the component can be denoted by the same reference numeral in each figure.

[0019] As shown in Figures 1-5 The self-tapping screw pull-out test device provided by the embodiments of the present application comprises: The upper clamp 2 adopts a split type adjustable clamping structure and is composed of at least two clamping blocks 21. The two clamping blocks 21 are arranged below the upper clamp 2, and semicircular grooves are formed on the opposite surfaces of the two clamping blocks 21. When the two semicircular grooves are closed, a clamping cavity 22 is formed. A displacement test point 23 is welded on one side edge of one of the clamping blocks 21, and the displacement test point 23 is arranged corresponding to the probe of the micrometer 1. The lower clamp 4 is arranged corresponding to the upper clamp 2 coaxially and vertically. The lower clamp 4 is provided with a vertical anchor rod 41, a transverse anchor rod 42 and a modular base material installation platform 43. The vertical anchor rod 41 and the transverse anchor rod 42 are both provided with adjustable bolts. The modular base material installation platform 43 is connected to the bottom of the lower clamp 4 through a sliding groove structure and a positioning pin. One side of the lower clamp 4 is fixedly connected with the micrometer 1 through a magnetic support. The probe of the micrometer 1 corresponds to the displacement test point 23 of the upper clamp 2. The equalizing assembly 6 is arranged on the inner side of the lower clamp 4, and the equalizing assembly 6 comprises an equalizing plate 61, the lower surface of the equalizing plate 61 is bonded with an elastic pad 62, the cross section of the elastic pad 62 is in a concave circular arc shape, one side of the elastic pad 62 is integrally formed with a plurality of protrusions 63, the protrusions 63 are in a rhombic structure, the plurality of protrusions 63 are arranged in an array, and the equalizing plate 61 and the elastic pad 62 are provided with a relief hole 64, the relief hole 64 is coaxially arranged with the clamping cavity 22, before the test, first screw the self-tapping screw 3 to be tested into the corresponding specification of the base material 5 according to the actual installation standard, then place the base material 5 with the assembled self-tapping screw 3 on the modular base material installation platform 43 of the lower clamp 4, complete the preliminary positioning of the base material through the bottom sliding groove structure of the modular base material installation platform 43, and then use the positioning pin for pre-fixing, then rotate the adjustable bolts on the vertical anchor rod 41 and the horizontal anchor rod 42 to adjust the height and horizontal position of the base material 5, so that the axis of the self-tapping screw 3 is coaxial with the clamping cavity 22 of the upper clamp 2, to avoid stress deflection during the pulling process, then according to the outer diameter specification of the self-tapping screw 3, adjust the two clamping blocks 21 on the upper clamp 2, so that the semicircular grooves on the two clamping blocks 21 are closed to form a clamping cavity 22 suitable for the self-tapping screw 3, and the self-tapping screw 3 is stably clamped, at this time, the concave circular arc shaped elastic pad 62 below the equalizing plate 61 in the equalizing assembly 6 on the inner side of the lower clamp 4 is closely attached to the surface of the base material 5, the plurality of rhombic protrusions 63 increase the contact friction force to prevent slipping during pulling, and the elastic pad 62 is deformed to disperse the clamping stress, to avoid local compression damage of the base material 5, and the coaxial relief hole 64 on the equalizing plate 61 and the elastic pad 62 provides a non-interference avoiding space for the self-tapping screw 3 pulling, after the test is started, the testing machine drives the upper clamp 2 to uniformly apply pulling force upward, at the same time, the micrometer instrument probe 1 on one side of the lower clamp 4 keeps precise point contact with the displacement test point 23 at the edge of the clamping block 21 of the upper clamp 2, and the small displacement change of the self-tapping screw 3 during the pulling process is captured and recorded in real time, until the self-tapping screw 3 is pulled out of the base material 5 or reaches the set pulling force value, the whole process realizes the collaborative optimization of clamping adaptability, centering accuracy, stress uniformity and displacement measurement accuracy by means of pure mechanical structure, and the operation is simple and the cost is controllable, thereby effectively guaranteeing the authenticity and reliability of the self-tapping screw 3 pulling test data, and adapting to the test requirements of various base materials and different specifications of screws, so as to guarantee the authenticity and reliability of the test results.

[0020] Further, as Figures 1-5As shown, the upper clamp 2 and the lower clamp 4 are both provided with a connecting hole 24 matched with the testing machine, and the upper end of the upper clamp 2 is provided with a strip-shaped sliding hole 25 on both sides, and the strip-shaped sliding hole 25 is provided with a sliding screw 26, one end of the sliding screw 26 is connected with a nut, and the other end of the sliding screw 26 is movably penetrated through the strip-shaped sliding hole 25 and fixedly connected with the clamping block 21. The connecting hole 24 on the upper clamp 2 and the lower clamp 4 is adapted and installed with the testing machine, and the strip-shaped sliding hole 25 on the upper end of the upper clamp 2 cooperates with the sliding screw 26 and the nut to adjust and drive the clamping block 21 to move along the strip-shaped sliding hole 25, so that the size of the clamping cavity 22 can be adjusted to adapt to the stable clamping of self-tapping screws 3 of different outer diameter specifications, while the clamping centering is guaranteed, and the adjustment operation is simplified.

[0021] Further, as shown in the figure, Figures 1-5 The inside of the clamping cavity 22 is provided with a self-tapping screw 3, the self-tapping screw 3 is sleeved with a gasket 31, and the head of the self-tapping screw 3 is arranged in the inside of the clamping cavity 22. The modular base material installation platform 43 is provided with a base material 5, the base material 5 is arranged on the inside of the lower clamp 4, and the rod part of the self-tapping screw 3 penetrates through the clamping cavity 22, the equalizing plate 61 and the elastic pad 62 and extends to the inside of the base material 5. The gasket 31 sleeved on the self-tapping screw 3 can disperse the local stress during pulling and protect the contact surface of the head of the self-tapping screw 3 and the clamping cavity 22. The rod part penetrates through the clamping cavity 22, the equalizing assembly 6 and is screwed into the inside of the base material 5 of the lower clamp 4, thereby guaranteeing the uniform transmission of the pulling force along the axis, avoiding the stress deviation, and ensuring the accuracy of the test data.

[0022] Further, as shown in the figure, Figures 1-5 The upper end of the lower clamp 4 is provided with a recess 7 on the inside, and the equalizing plate 61 is installed in the inside of the recess 7 through a plurality of uniformly distributed general screws. The recess 7 on the inside of the upper end of the lower clamp 4 cooperates with the general screws to realize the detachable and stable installation of the equalizing assembly 6, guarantee the coaxial centering of the equalizing assembly 6 and the clamping cavity 22, and facilitate the replacement of the elastic pad 62 as needed to adapt to different test scenarios.

[0023] Further, as shown in the figure, Figures 1-5 The connecting part of the upper clamp 2 and the testing machine is provided with an adjustable elastic compensation assembly. The adjustable elastic compensation assembly includes a spring gasket and a strain sensing unit. The strain sensing unit can detect the deformation of the upper clamp 2 during the loading process in real time, and feed back the deformation data to the control system to automatically correct the pulling force data, thereby significantly improving the accuracy and repeatability of the test results.

[0024] Further, as shown in the figure, Figures 1-5As shown, a signal acquisition module is provided between the micrometer 1 and the testing machine control system. The signal acquisition module can synchronously acquire the pull-out force signal output by the universal testing machine and the displacement signal output by the micrometer 1, and perform real-time synchronization and correction through the built-in algorithm. After the test, the system can automatically output the corrected force-displacement curve, thereby avoiding errors that may be introduced in manual reading and subsequent data processing.

[0025] like Figures 1-5 As shown, the working principle of a self-tapping screw pull-out testing device is as follows: Before the test, the self-tapping screw 3 to be tested is screwed into the corresponding specification substrate 5 according to the actual installation standard. The substrate with the self-tapping screw 3 is placed on the modular substrate mounting platform 43 of the lower clamp 4. The initial positioning is completed by the bottom sliding groove structure of the modular substrate mounting platform 43 and pre-fixed with the positioning pin. Then, the adjustable bolts on the vertical anchor rod 41 and the horizontal anchor rod 42 are rotated to adjust the vertical height and horizontal position of the substrate 5 to ensure that the axis of the self-tapping screw 3 is precisely coaxially aligned with the clamping cavity 22 on the upper clamp 2, so as to avoid the force deviation during pull-out from the root. At the same time, the inner groove 7 on the upper end of the lower clamp 4 is used to realize the detachable and stable installation of the pressure equalization component 6 through the universal screw, ensuring that the pressure equalization component 6 is coaxial with the clamping cavity 22. The elastic pad 62 can also be replaced as needed to adapt to different test scenarios. Then, according to the outer diameter specification of the self-tapping screw 3, the two clamping blocks 21 are adjusted to move along the strip-shaped sliding holes 25 on both sides of the upper end of the upper clamp 2 in conjunction with the sliding screw 26 and the nut. The semi-circular grooves on opposite sides of the clamping block 21 close to form a clamping cavity 22 that fits the self-tapping screw 3, thus firmly clamping the head of the self-tapping screw 3. The washer 31 fitted on the self-tapping screw 3 can disperse local stress during pull-out and protect the contact surface between the screw head and the clamping cavity 22. Its rod passes through the clamping cavity 22, the pressure equalizing plate 61 of the pressure equalizing component 6 and the elastic pad 62 and is screwed into the substrate to form a stable force system. At this time, the concave arc-shaped elastic pad 62 in the pressure equalizing component 6 is in close contact with the surface of the substrate 5. Several diamond-shaped protrusions 63 not only increase the contact friction to prevent slippage, but also disperse the clamping stress through elastic deformation to avoid local pressure damage to the substrate 5. The clearance hole 64 provides interference-free clearance space for screw pull-out. An adjustable elastic compensation component is set at the connection between the upper clamp 2 and the testing machine. Its strain sensing unit can detect the deformation of the upper clamp itself during the loading process in real time and feed the data back to the control system to automatically correct the pull-out force data, thereby improving the test accuracy and repeatability. After the test is started, the testing machine drives the upper clamp 2 to apply pulling force at a constant speed through the connecting aperture 24. The probe 1 of the micrometer on one side of the lower clamp 4 keeps accurate point contact with the displacement test point 23 at the edge of the clamping block 21 of the upper clamp 2, captures the tiny displacement change of the screw in real time, and the signal acquisition module between the micrometer 1 and the control system of the testing machine synchronously collects the pulling force signal and the displacement signal, synchronously corrects in real time through the built-in algorithm, avoids the error of manual reading and post-data processing, and thus effectively guarantees the authenticity, reliability and repeatability of the pulling test data of the self-tapping screw 3 of different substrates and specifications.

[0026] The above is only a few specific embodiments of the present application, but the embodiments of the present application are not limited thereto, and any changes that can be thought of by those skilled in the art shall fall within the protection scope of the present application.

Claims

1. A self-tapping screw pull-out test device, characterized in that, include: The upper clamp adopts a split adjustable clamping structure, which is composed of at least two clamping blocks. The two clamping blocks are located below the upper clamp, and the two clamping blocks have semi-circular grooves on their opposite surfaces. When the two semi-circular grooves are closed, they form a clamping cavity. A displacement test point is welded to one side edge of one of the clamping blocks, and the displacement test point is set to correspond to the probe of the per mille meter. The lower clamp is coaxially aligned with the upper clamp. The lower clamp is equipped with vertical anchor rods, horizontal anchor rods, and a modular substrate mounting platform. Adjustable bolts are provided on both the vertical and horizontal anchor rods. The modular substrate mounting platform is connected to the bottom of the lower clamp via a sliding groove structure and a positioning pin. A micrometer is fixedly connected to one side of the lower clamp via a magnetic bracket. The probe of the micrometer corresponds to the displacement test point of the upper clamp. A pressure equalization assembly is disposed on the inner side of the lower clamp. The pressure equalization assembly includes: a pressure equalization plate, an elastic pad bonded to the lower surface of the pressure equalization plate, the cross-section of the elastic pad being concave arc-shaped, and a plurality of protrusions integrally formed on one side of the elastic pad, and clearance holes are provided on the pressure equalization plate and the elastic pad, the clearance holes being coaxially arranged with the clamping cavity.

2. The self-tapping screw pull-out test apparatus as described in claim 1, characterized in that, The protrusions are rhomboid in shape, and several of the protrusions are arranged in an array.

3. The self-tapping screw pull-out test apparatus as described in claim 1, characterized in that, Both the upper clamp and the lower clamp are provided with connection holes that match the testing machine. The upper clamp is provided with strip-shaped sliding holes on both sides of its upper end. A sliding screw is provided on the strip-shaped sliding hole. One end of the sliding screw is connected to a nut, and the other end of the sliding screw movably passes through the strip-shaped sliding hole and is fixedly connected to the clamping block.

4. The self-tapping screw pull-out test apparatus as described in claim 3, characterized in that, The clamping cavity is provided with a self-tapping screw, the self-tapping screw is fitted with a washer, and the head of the self-tapping screw is located inside the clamping cavity.

5. The self-tapping screw pull-out test apparatus as described in claim 4, characterized in that, The modular substrate mounting platform is provided with a substrate, which is located inside the lower clamp, and the shank of the self-tapping screw passes through the clamping cavity, the pressure equalizing plate, and the elastic pad and extends into the interior of the substrate.

6. The self-tapping screw pull-out test apparatus as described in claim 1, characterized in that, The upper inner side of the lower clamp is provided with a groove, and the pressure equalizing plate is installed inside the groove by a number of evenly distributed universal screws.

7. The self-tapping screw pull-out test apparatus as described in claim 1, characterized in that, The connection between the upper clamp and the testing machine is provided with an adjustable elastic compensation component, which includes a spring washer and a strain sensing unit.

8. The self-tapping screw pull-out test apparatus as described in claim 1, characterized in that, A signal acquisition module is provided between the thousandths meter and the testing machine control system.

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