Loading equipment for testing the bending strength and bending stiffness of bone plates

Abstract

The present invention discloses a loading device for testing the bending strength and bending stiffness of a bone plate, and belongs to the technical field of testing the bending performance of a metal bone plate. It includes a workbench, a lifting shaft, a loading plate, a bone plate clamping and positioning component, an end longitudinal displacement equalizing component, an end bending angle equalizing component, and a radial loading component. The bone plate clamping and positioning component is used to position and clamp the two ends of the metal bone plate; the end longitudinal displacement equalizing component and the end bending angle equalizing component are used to drive the two ends of the metal bone plate to synchronously move in opposite directions and synchronously rotate in opposite directions during the bending test, respectively, so as to achieve the effect of equal longitudinal displacement distribution and equal rotation angle distribution at the two ends; the radial loading component is used to implement two-point centralized loading on the metal bone plate. The present invention is a loading device with a reasonable structure, equal longitudinal displacement distribution and equal rotation angle distribution functions, and can significantly improve the loading accuracy of the metal bone plate bending test.

Description

Technical Field

[0001] The invention mainly relates to the technical field of metal bone plate bending performance detection, and in particular to a loading device for detecting the bending strength and bending stiffness of a bone plate. Background Art

[0002] Metal plates have broad application prospects as bone-binding implants for fracture connection. Generally, metal plates produced by manufacturers need to undergo a series of relevant performance testing tests before application, including: performance determination of bending stiffness and bending strength. The displacement method is used to determine the bending strength and stiffness of metal plates, that is, loads are applied to the metal plate through four symmetrically distributed rollers so that the metal plate undergoes four-point bending, and the maximum relative displacement of the metal plate during bending and the relative displacement at the contact position of the two inner rollers are measured with the help of a measuring tool, and the equivalent bending stiffness and equivalent bending strength formula given in the industry standard (YY / T 0342-2020) are calculated. When the prior art implements the four-point bending test loading, one of the two outer rollers is usually used to fix the specimen to limit the longitudinal movement of one end of the metal plate, and the other outer roller is only used to support the specimen. Therefore, although the existing technology realizes the four-point bending loading of the bone plate, the asymmetric constraint form of the two outer rollers on the metal bone plate causes the longitudinal displacement and rotation angle of the two ends of the metal bone plate to be unequal, resulting in a large error in the test result. Therefore, there is an urgent need for a four-point bending loading device for metal bone plates that can significantly improve the test accuracy. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in view of the technical problems existing in the prior art, the present invention provides a loading device with a reasonable structure, equal longitudinal displacement distribution and equal rotation angle distribution functions, which can significantly improve the loading accuracy of the metal bone plate bending test.

[0004] In order to solve the above problems, the solution proposed in the present invention is: a loading device for detecting the bending strength and bending stiffness of a bone plate, comprising a workbench with a through hole at the center, a lifting shaft sliding through the through hole, and a loading plate fixedly mounted on the upper end of the lifting shaft; it also includes: a bone plate clamping and positioning component, an end longitudinal displacement equalizing component, an end bending angle equalizing component, and a radial loading component.

[0005] The bone plate clamping and positioning component is installed on the workbench and is used for positioning and clamping the two ends of the metal bone plate.

[0006] The end longitudinal displacement equalization component is installed between the workbench and the plate clamping and positioning component, and is used to drive the two ends of the metal plate clamped by the plate clamping and positioning component to move synchronously in opposite directions during the bending test, thereby achieving equal longitudinal displacement distribution at the two ends.

[0007] The end bending angle equalizing component is installed between the end longitudinal displacement equalizing component and the plate clamping and positioning component, and is used to drive the two ends of the metal plate clamped by the plate clamping and positioning component to rotate synchronously in opposite directions during the bending test, thereby achieving equal angle distribution of the two ends.

[0008] The radial loading assembly is radially slidably mounted on the workbench and is hingedly connected to the loading plate via a loading link, and is used to convert the load from the loading plate in the vertical direction into a concentrated load in the horizontal plane, thereby implementing two-point concentrated loading on the metal bone plate.

[0009] The bone plate clamping and positioning component includes two end clamping assemblies with completely identical structures and symmetrically distributed about the sliding direction of the radial loading assembly, and the end clamping assemblies include: a first bracket plate that is slidably and rotatably mounted on the workbench, a fixed clamping roller that is rotatably mounted on the first bracket plate, a translational clamping roller that is slidably and rotatably mounted on the first bracket plate, and a clamping locking mechanism that drives the translational clamping roller and the fixed clamping roller to move away from or closer to each other; the cross-section of the fixed clamping roller is an ellipse, and the longitudinal section boundary line passing through the axis is a parabola; the translational clamping roller and the fixed clamping roller have completely identical structural features, and the axes are both parallel to the lifting axis.

[0010] Furthermore, the end longitudinal displacement equalizing assembly includes: a first equalizing slider and two second equalizing sliders slidably mounted on the workbench, a first connecting rod whose two ends are hingedly connected to the first equalizing slider and one of the second equalizing sliders, and a second connecting rod whose two ends are hingedly connected to the first equalizing slider and another of the second equalizing sliders; the first equalizing slider slides colinearly with the radial loading assembly, and the two second equalizing sliders slide colinearly and are symmetrically distributed about the sliding direction of the first equalizing slider; the first bracket plates in the two end clamping assemblies are rotatably mounted on the two second equalizing sliders, respectively.

[0011] Furthermore, the end bending angle equalizing component includes: a third rotating shaft whose lower end is rotatably mounted on the second equalizing slider and whose upper end is fixedly connected to the first bracket plate, a pulley fixedly mounted on the third rotating shaft, a torsion spring which is sleeved on the third rotating shaft and whose two ends are respectively connected to the second equalizing slider and the pulley, and a reverse synchronous belt; the number of the third rotating shaft, the number of the pulleys and the number of the torsion springs are all two; the two third rotating shafts are adapted to the two second equalizing sliders, and the two pulleys are connected via the reverse synchronous belt transmission.

[0012] Furthermore, the radial loading assembly includes: a loading slider installed radially sliding along the workbench, a third bracket plate fixedly installed on the loading slider and hingedly connected to the loading connecting rod at one end, a first loading roller and a second loading roller rotatably installed on the third bracket plate and with axes parallel to each other; the first loading roller and the second loading roller are symmetrically distributed about the sliding direction of the loading slider.

[0013] Furthermore, the number of the radial loading components, the number of the plate clamping and positioning components, the number of the end longitudinal displacement equalization components and the number of the end bending angle equalization components are all three; the three radial loading components are symmetrically distributed about the lifting axis and are matched with the three plate clamping and positioning components; the three end longitudinal displacement equalization components, the three end bending angle equalization components and the three plate clamping and positioning components are matched one by one.

[0014] Furthermore, the workbench is provided with a radial intermittent groove along the radial direction and a vertical intermittent groove perpendicular to the radial intermittent groove, and a loading slider and a first equal-dividing slider are slidably installed in the radial intermittent groove from the inside to the outside in sequence, and two of the second equal-dividing sliders are slidably installed inside the vertical intermittent groove; the two second equal-dividing sliders are symmetrical about the radial intermittent groove; the number of the radial intermittent grooves and the vertical intermittent grooves are three each, the three radial intermittent grooves are adapted to the three radial loading components, and the three vertical intermittent grooves are respectively adapted to the three bone plate clamping and positioning components.

[0015] Furthermore, the clamping and locking mechanism includes: a second bracket plate slidably connected to the first bracket plate, and a locking screw threadedly connecting the first bracket plate and the second bracket plate.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: a loading device for testing the bending strength and bending stiffness of a bone plate of the present invention is provided with an end longitudinal displacement equalization component, which can make the two ends of the metal bone plate synchronously translate in opposite directions during the bending test, ensuring that the displacements of the two ends along the longitudinal direction are always equal, achieving the effect of longitudinal equal displacement distribution; the present invention is provided with an end bending angle equalization component, which is used to drive the two ends of the metal bone plate clamped by the bone plate clamping and positioning component to rotate synchronously in opposite directions during the bending test, ensuring that the angles of the reverse rotation of the two ends are always equal, achieving the effect of equal angle distribution; in addition, the present invention is also provided with a fixed clamping roller and a translation clamping roller with an elliptical cross-section, which squeeze and clamp the metal bone plate through the short axis of the ellipse, thereby improving the loading stability during the bending process. It can be seen from this that the present invention is a loading device with a reasonable structure, longitudinal equal displacement distribution and equal angle distribution functions, which can significantly improve the loading accuracy of the metal bone plate bending test. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structural principle of the loading device for testing the bending strength and bending stiffness of a bone plate of the present invention.

[0018] Figure 2 yes Figure 1 AA rotated section view schematic diagram.

[0019] Figure 3 It is a schematic diagram of the position distribution of radial discontinuous chutes and vertical discontinuous chutes on the workbench.

[0020] Figure 4 It is a schematic diagram of the structural principle of the end clamping assembly of the present invention.

[0021] Figure 5 It is a schematic diagram of the bending loading principle of a single metal bone plate.

[0022] Figure 6 It is a schematic diagram of the structural principle of the end bending angle equalizing component of the present invention.

[0023] Figure 7 It is a schematic diagram of the connection between the pulley and the reverse synchronous belt drive.

[0024] In the figure, 11—workbench; 110—through hole; 111—radial discontinuous slide; 112—vertical discontinuous slide; 12—loading plate; 13—lifting shaft; 14—loading connecting rod; 2—metal bone plate; 3—end clamping assembly; 31—first bracket plate; 310—locking slide; 32—locking slider; 33—first rotating shaft; 34—fixed clamping roller; 35—second rotating shaft; 36—translational clamping roller; 37—locking screw; 38—second bracket plate ; 4—end bending angle equalizing assembly; 41—third rotating shaft; 42—pulley; 43—torsion spring; 44—reverse synchronous belt; 5—end longitudinal displacement equalizing assembly; 51—first equalizing slider; 52—first connecting rod; 53—second connecting rod; 54—second equalizing slider; 6—radial loading assembly; 61—third bracket plate; 62—fourth rotating shaft; 63—first loading roller; 64—fifth rotating shaft; 65—second loading roller; 66—loading slider. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Figure 1 The horizontal plane where the middle workbench 11 is located is recorded as the XY plane; the vertical direction perpendicular to the workbench 11 is recorded as the Z-axis direction; the length direction of the metal plate 2 before bending and deformation is recorded as the longitudinal direction; the displacement of the two ends of the clamped metal plate 2 along the direction of the vertical discontinuous slide groove 112 is recorded as the longitudinal displacement; the metal plate 2 used for the test is recorded as a specimen, and the left and right parts of the metal plate 2 clamped by the end clamping assembly 3 are respectively recorded as the left end and right end of the specimen.

[0026] See also Figures 1 to 3The loading device for testing the bending strength and bending stiffness of a bone plate of the present invention comprises a workbench 11 with a through hole 110 at the center, a lifting shaft 13 sliding through the through hole 110, a loading plate 12 fixedly mounted on the upper end of the lifting shaft 13, a bone plate clamping and positioning component, an end longitudinal displacement equalizing component 5, an end bending angle equalizing component 4, and a radial loading component 6; in specific implementation, the workbench 11 is arranged along the XY plane, and a plurality of supporting legs (not shown in the figure) are arranged at the bottom along the Z-axis direction; the workbench 11 is a circular flat plate, a through hole 110 is arranged at the center of the circular flat plate, a linear bearing is arranged in the through hole 110, the lifting shaft 13 is arranged along the Z-axis direction, and passes through the linear bearing downward to be slidably connected to the workbench 11; The bone plate clamping and positioning components clamp the two ends of the sample, and the radial loading component 6 can symmetrically apply concentrated loads to the two inner points of the sample, so that the sample can bend and deform in the XY plane; the number of radial loading components 6, the number of bone plate clamping and positioning components, the number of end longitudinal displacement equalization components 5 and the number of end bending angle equalization components 4 are all three; the three radial loading components 6 are symmetrically distributed about the lifting axis 13, the three bone plate clamping and positioning components are symmetrically distributed about the lifting axis 13, and the three radial loading components 6 are adapted to the three bone plate clamping and positioning components, and the three end longitudinal displacement equalization components 5, the three end bending angle equalization components 4 and the three bone plate clamping and positioning components are adapted one by one. The use of three axially symmetrically distributed radial loading components 6 and three bone plate clamping and positioning components can ensure that the three samples have exactly the same loading history, thereby effectively eliminating the bending deformation error caused by different loading histories and further improving the measurement accuracy. Preferably, the workbench 11 is provided with a radial discontinuous groove 111 along the radial direction and a vertical discontinuous groove 112 perpendicular to the radial discontinuous groove 111. The radial discontinuous groove 111 is composed of a collinear radial groove A and a radial groove B. A loading slider 66 is slidably installed in the radial groove A close to the lifting shaft 13, and the radial loading assembly 6 is fixedly installed on the loading slider 66; a first equal-dividing slider 51 is slidably installed in the radial groove B away from the lifting shaft 13; the vertical discontinuous groove 112 is composed of a collinear linear groove A and a linear groove B, and the linear groove A and the linear groove B are symmetrically opened on the radial discontinuous groove 1 On both sides of 11, and perpendicular to the radial intermittent slide groove 111; a second evenly dividing slider 54 is respectively installed inside the linear slide groove A and the linear slide groove B, and the two second evenly dividing sliders 54 are symmetrical about the radial intermittent slide groove 111; as a preferred embodiment, the number of radial intermittent slide grooves 111 and vertical intermittent slide grooves 112 are three, the three radial intermittent slide grooves 111 are symmetrically distributed about the lifting axis 13, and the three vertical intermittent slide grooves 112 are symmetrically distributed about the lifting axis 13; the three radial intermittent slide grooves 111 are adapted to the three radial loading components 6, and the three vertical intermittent slide grooves 112 are respectively adapted to the three bone plate clamping and positioning components.

[0027] See also Figure 1 , Figure 2 and Figure 4 The bone plate clamping and positioning component is installed on the workbench 11, and is used to position and clamp the two ends of the metal bone plate 2; the bone plate clamping and positioning component includes two end clamping components 3 with completely identical structures and symmetrically distributed about the sliding direction of the radial loading component 6, and the end clamping component 3 includes: a first bracket plate 31 slidably and rotatably installed on the workbench 11, a fixed clamping roller 34 rotatably installed on the first bracket plate 31, a translation clamping roller 36 slidably and rotatably installed on the first bracket plate 31, and a clamping and locking mechanism for driving the translation clamping roller 36 and the fixed clamping roller 34 to move away from or approach each other; the clamping and locking mechanism includes a second bracket plate 38 slidably connected to the first bracket plate 31, and a locking screw 37 threadedly connected to the first bracket plate 31 and the second bracket plate 38. The cross section of the fixed clamping roller 34 is an ellipse, and the boundary line of the longitudinal section passing through the axis is a parabola; the translation clamping roller 36 has completely identical structural features with the fixed clamping roller 34, and the axes are both parallel to the lifting shaft 13. In the specific implementation, the first bracket plate 31 and the second bracket plate 38 are both U-shaped frames, the middle arm of the U-shaped frame is arranged along the Z-axis direction, and the two side arms of the U-shaped frame are parallel to the radial discontinuous slide groove 111; a locking slide groove 310 is provided on the two side arms of the first bracket plate 31 along the arm length direction, and a locking slider 32 is installed inside the locking slide groove 310; the translation clamping roller 36 is sleeved on the second rotating shaft 35, and the two ends of the second rotating shaft 35 are respectively rotatably installed on the two locking sliders 32; the fixed clamping roller 34 is sleeved on On the first rotating shaft 33, the two ends of the first rotating shaft 33 are rotatably mounted on the two side arms of the first bracket plate 31, and the second rotating shaft 35 is always parallel to the first rotating shaft 33; the two side arms of the second bracket plate 38 are fixedly connected to the two locking sliders 32, and the distance between the second bracket plate 38 and the first bracket plate 31 is changed by rotating the locking screw 37, and then the translation clamping roller 36 is pushed or pulled by the locking slider 32 to move toward or away from the fixed clamping roller 34, thereby clamping or loosening the sample. In specific applications, the length of the sample is parallel to the vertical intermittent slide groove 112, the width of the sample is along the Z-axis direction, and the thickness of the sample is parallel to the radial intermittent slide groove 111. Before bending, the fixed clamping roller 34 and the translational clamping roller 36 squeeze the sample through the short axis of the ellipse, that is, the distance between the fixed clamping roller 34 and the translational clamping roller 36 is minimum; when the sample is bent, the fixed clamping roller 34 and the translational clamping roller 36 cannot rotate around their own axes, thereby effectively preventing the sample from slipping during the bending process and improving the clamping stability of the sample during the bending process.

[0028] See also Figure 1 , Figure 2 and Figure 5The end longitudinal displacement equalization component 5 is installed between the workbench 11 and the plate clamping and positioning component, and is used to drive the two ends of the metal plate 2 clamped by the plate clamping and positioning component to move synchronously in opposite directions during the bending test, thereby realizing equal longitudinal displacement distribution of the two ends; preferably, the end longitudinal displacement equalization component 5 includes a first equalization slider 51 and two second equalization sliders 54 slidably installed on the workbench 11, a first connecting rod 52 hingedly connected to the first equalization slider 51 and a second equalization slider 54 at both ends, and a second connecting rod 53 hingedly connected to the first equalization slider 51 and another second equalization slider 54 at both ends; the first equalization slider 51 slides in line with the radial loading component 6, and the two second equalization sliders 54 slide in line and are symmetrically distributed about the radial intermittent groove 111. In specific implementation, the first connecting rod 52 and the second connecting rod 53 are symmetrically arranged about the corresponding radial intermittent groove 111. When the metal bone plate 2 is bent by the load of the radial loading assembly 6 , the two second equally-dividing sliders 54 approach each other, and the first equally-dividing slider 51 is pushed away from the lifting shaft 13 through the first connecting rod 52 and the second connecting rod 53 .

[0029] See also Figure 2 , Figure 6 and Figure 7 The end bending angle equalizing component 4 is installed between the end longitudinal displacement equalizing component 5 and the plate clamping and positioning component, and is used to drive the two ends of the metal plate 2 clamped by the plate clamping and positioning component to rotate synchronously in the opposite direction during the bending test, thereby realizing equal rotation angle distribution at the two ends; preferably, the end bending angle equalizing component 4 includes a third rotating shaft 41 whose lower end is rotatably installed on the second equalizing slider 54 and the upper end is fixedly connected to the first bracket plate 31, a pulley 42 fixedly installed on the third rotating shaft 41, a torsion spring 43 mounted on the third rotating shaft 41 and connected to the second equalizing slider 54 and the pulley 42 at both ends, and a reverse synchronous belt 44; the number of the third rotating shaft 41, the number of the pulleys 42 and the number of the torsion springs 43 are all two; the two third rotating shafts 41 are adapted to the two second equalizing sliders 54, and the two pulleys 42 are connected through the reverse synchronous belt 44. In specific implementation, the lower end of the third rotating shaft 41 is rotationally connected to the second equally dividing slider 54 through a rolling bearing, and the torsional stiffness of the torsion spring 43 is as small as possible. Preferably, the product of the torsional stiffness of the torsion spring 43 and the maximum torsion angle in the bending deformation is not greater than one percent of the maximum bending moment of the metal bone plate 2. When the metal bone plate 2 is bent by the load of the radial loading component 6, due to the action of the reverse synchronous belt 44, the left end clamping component 3 in the same bone plate clamping and positioning component rotates in the clockwise direction, and the right end clamping component 3 rotates in the counterclockwise direction, and the two rotation angles are equal.

[0030] See also Figure 1 , Figure 2 and Figure 5 The radial loading assembly 6 is radially slidably mounted on the workbench 11 and is hingedly connected to the loading plate 12 through the loading link 14, and is used to convert the load from the loading plate 12 in the vertical direction into a concentrated load in the horizontal plane, thereby implementing two-point concentrated loading on the metal bone plate 2. Preferably, the radial loading assembly 6 includes a loading slider 66 radially slidably mounted along the workbench 11, a third bracket plate 61 fixedly mounted on the loading slider 66 and hingedly connected to the loading link 14 at one end, a first loading roller 63 and a second loading roller 65 rotatably mounted on the third bracket plate 61 and having axes parallel to each other; the first loading roller 63 and the second loading roller 65 are symmetrically distributed about the sliding direction of the loading slider 66. In specific implementation, the third bracket plate 61 includes a triangular plate A, a triangle B and an intermediate plate. The triangular plate A and the triangle B are fixedly connected in the middle through the intermediate plate one above and one below; one end of the loading link 14 is hingedly connected to the side of the loading plate 12, and the other end is hingedly connected to the intermediate plate in the third bracket plate 61; the number of loading links 14 is also three, which are respectively adapted to the three radial loading assemblies 6. Both ends of the fourth rotating shaft 62 and the fifth rotating shaft 64 whose axes are parallel to the Z axis are rotatably mounted on the triangular plate A and the triangle B respectively, the first loading roller 63 is sleeved on the outside of the fourth rotating shaft 62, and the second loading roller 65 is sleeved on the outside of the fifth rotating shaft 64; the cross section of the first loading roller 63 is circular, and the boundary line of the longitudinal section is a parabola. The structural features of the second loading roller 65 are exactly the same as those of the first loading roller 63; the parabola vertex position of the fixed clamping roller 34, the parabola vertex position of the translational clamping roller 36, the parabola vertex position of the first loading roller 63 and the parabola vertex position of the second loading roller 65 are equal in height along the Z axis direction.

[0031] Working principle of the bone plate clamping and positioning component: Before the test, the two ends of the sample are respectively placed in the two end clamping assemblies 3 in the bone plate clamping and positioning component, that is, the two ends of the sample are located between the corresponding fixed clamping rollers 34 and the translation clamping rollers 36, and the locking screw 37 is rotated in the forward direction, and the second bracket plate 38 moves toward the first bracket plate 31, pushing the locking slider 32 and the translation clamping roller 36 installed on the locking slider 32 to move toward the fixed clamping roller 34 until the elliptical minor axis of the fixed clamping roller 34 and the elliptical minor axis of the translation clamping roller 36 squeeze the sample and clamp the two ends of the sample; after the test, the locking screw 37 is rotated in the reverse direction, the second bracket plate 38 moves away from the first bracket plate 31, and the locking slider 32 and the translation clamping roller 36 installed on the locking slider 32 move away from the fixed clamping roller 34, and the sample is released.

[0032] Working principle of the end bending angle equalization component 4: The radial loading component 6 slowly loads the sample, and the sample is bent and deformed. During the bending process, the left end of the sample will rotate clockwise, and the right end of the sample will rotate counterclockwise; the reverse rotation of the left end and the right end will respectively drive the corresponding third rotating shaft 41 to rotate in the opposite direction, and then drive the pulley 42 installed on the third rotating shaft 41 to rotate in the opposite direction. Since the two pulleys 42 in the same end bending angle equalization component 4 are connected by a reverse synchronous belt 44, the rotation angles of the two pulleys 42 are always equal, so the rotation angles of the left end and the right end of the same sample must be equal in size, that is, the present invention achieves the effect of end bending angle equalization.

[0033] Working principle of the end longitudinal displacement equalization component 5: The radial loading component 6 slowly loads the sample, and the sample is bent and deformed. During the bending process, the total length of the sample remains unchanged, but the middle part of the sample will gradually move away from the lifting shaft 13 along the radial direction of the workbench 11, so the left and right ends of the sample will approach each other; the translation of the left and right ends of the sample will drive the two second equalization sliders 54 to approach each other through the third rotating shaft 41; since the structural characteristics of the end longitudinal displacement equalization component 5 are symmetrical about the radial discontinuous slide groove 111, that is, the rotation angles of the first connecting rod 52 and the second connecting rod 53 are always equal, and the translation displacements of the two paired second equalization sliders 54 are always equal, the absolute displacements of the left and right ends of the sample must be equal, that is, the present invention achieves the effect of equalizing the end longitudinal displacement.

[0034] The working process of the present invention is as follows: the first step is to connect the loading plate 12 to an external press so that a load is applied to the loading plate 12 through the press; the second step is to place three specimens in three bone plate clamping and positioning components respectively, adjust the elliptical minor axis directions of the fixed clamping roller 34 and the translation clamping roller 36 so that they face the specimens, and tighten the locking screws 37 so that the left and right ends of the specimens are clamped by the two end clamping assemblies 3 respectively; the third step is that the press drives the loading plate 12 to move downward and implements slow loading. The loading plate 12 moves downward, and drives the three radial loading assemblies 6 to slide radially along the workbench 11 through the three loading connecting rods 14, until the first loading roller 63 and the second loading roller 65 in the radial loading assembly 6 contact the corresponding sample; then the press drives the loading plate 12 to load slowly, that is, the three samples are loaded to perform a four-point bending test, and the load is loaded until the sample breaks or the load of the press reaches the set test load; in the fourth step, after the bending loading is completed, the maximum deflection deformation at the longitudinal midpoint of the sample and the deflection deformation at the first loading roller 63 and the second loading roller 65 are measured by a measuring tool, and the bending stiffness and bending strength of the sample are calculated according to the equivalent bending stiffness and bending strength formula given in the industry standard (YY / T 0342-2020); in the fifth step, after the test is completed, the press drives the loading plate 12 to rise back to the initial position, and rotates the locking screw 37 in the opposite direction, and the end clamping assembly 3 releases the sample.

[0035] The above are only specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should fall within the protection scope of the present invention.

Claims

1. A loading device for testing the bending strength and bending stiffness of a bone plate, comprising a workbench (11) with a through hole (110) at the center, a lifting shaft (13) sliding through the through hole (110), and a loading plate (12) fixedly mounted on the upper end of the lifting shaft (13); characterized in that: Also includes: A bone plate clamping and positioning component, an end longitudinal displacement equalizing component (5), an end bending angle equalizing component (4), and a radial loading component (6); The bone plate clamping and positioning component is installed on the workbench (11) and is used to position and clamp the two ends of the metal bone plate (2); the end longitudinal displacement equalizing component (5) is installed between the workbench (11) and the bone plate clamping and positioning component and is used to drive the two ends of the metal bone plate (2) clamped by the bone plate clamping and positioning component to move synchronously in opposite directions during the bending test, thereby achieving equal longitudinal displacement distribution of the two ends; the end bending angle equalizing component (4) is installed between the end longitudinal displacement equalizing component (5) and the end longitudinal displacement equalizing component (5). The bone plate clamping and positioning components are used to drive the two ends of the metal bone plate (2) clamped by the bone plate clamping and positioning components to rotate synchronously in opposite directions during the bending test, thereby achieving equal rotation angle distribution of the two ends; the radial loading component (6) is radially slidably mounted on the workbench (11) and is hingedly connected to the loading plate (12) through a loading connecting rod (14), and is used to convert the load from the loading plate (12) in the vertical direction into a concentrated load in the horizontal plane, thereby implementing two-point concentrated loading on the metal bone plate (2); The bone plate clamping and positioning component comprises two end clamping assemblies (3) of completely identical structure and symmetrically distributed with respect to the sliding direction of the radial loading assembly (6), the end clamping assembly (3) comprising: a first bracket plate (31) slidably and rotatably mounted on the workbench (11), a fixed clamping roller (34) rotatably mounted on the first bracket plate (31), a translational clamping roller (36) slidably and rotatably mounted on the first bracket plate (31), and a clamping locking mechanism for driving the translational clamping roller (36) and the fixed clamping roller (34) to move away from or approach each other; the cross section of the fixed clamping roller (34) is an ellipse, and the longitudinal section boundary line passing through the axis is a parabola; the translational clamping roller (36) and the fixed clamping roller (34) have completely identical structural features, and the axes are both parallel to the lifting shaft (13); The end longitudinal displacement equalizing assembly (5) comprises: a first equalizing slider (51) and two second equalizing sliders (54) slidably mounted on the workbench (11), a first connecting rod (52) whose two ends are respectively hingedly connected to the first equalizing slider (51) and one second equalizing slider (54), and a second connecting rod (53) whose two ends are respectively hingedly connected to the first equalizing slider (51) and another second equalizing slider (54); the first equalizing slider (51) slides in a colinear manner with the radial loading assembly (6), and the two second equalizing sliders (54) slide in a colinear manner and are symmetrically distributed with respect to the sliding direction of the first equalizing slider (51); the first bracket plates (31) in the two end clamping assemblies (3) are respectively rotatably mounted on the two second equalizing sliders (54); The end bending angle equalizing component (4) comprises: a third rotating shaft (41) whose lower end is rotatably mounted on the second equalizing slider (54) and whose upper end is fixedly connected to the first bracket plate (31), a pulley (42) fixedly mounted on the third rotating shaft (41), a torsion spring (43) sleeved on the third rotating shaft (41) and whose two ends are respectively connected to the second equalizing slider (54) and the pulley (42), and a reverse synchronous belt (44); the number of the third rotating shaft (41), the number of the pulleys (42) and the number of the torsion springs (43) are all two; the two third rotating shafts (41) are matched with the two second equalizing sliders (54), and the two pulleys (42) are connected through the reverse synchronous belt (44).

2. The loading device for testing the bending strength and bending stiffness of a bone plate according to claim 1, characterized in that: The radial loading assembly (6) comprises: a loading slider (66) radially slidably mounted along the workbench (11), a third bracket plate (61) fixedly mounted on the loading slider (66) and hingedly connected to the loading connecting rod (14) at one end, and a first loading roller (63) and a second loading roller (65) rotatably mounted on the third bracket plate (61) and having axes parallel to each other; the first loading roller (63) and the second loading roller (65) are symmetrically distributed with respect to the sliding direction of the loading slider (66).

3. The loading device for testing the bending strength and bending stiffness of a bone plate according to claim 2, characterized in that: The number of the radial loading components (6), the number of the bone plate clamping and positioning components, the number of the end longitudinal displacement equalization components (5) and the number of the end bending angle equalization components (4) are all three; the three radial loading components (6) are symmetrically distributed about the lifting axis (13) and are compatible with the three bone plate clamping and positioning components; the three end longitudinal displacement equalization components (5), the three end bending angle equalization components (4) and the three bone plate clamping and positioning components are compatible one by one.

4. The loading device for testing the bending strength and bending stiffness of a bone plate according to claim 3, characterized in that: The workbench (11) is provided with a radial intermittent groove (111) along the radial direction and a vertical intermittent groove (112) perpendicular to the radial intermittent groove (111); a loading slider (66) and a first equal-dividing slider (51) are slidably installed in the radial intermittent groove (111) from the inside to the outside in sequence; two second equal-dividing sliders (54) are slidably installed inside the vertical intermittent groove (112); the two second equal-dividing sliders (54) are symmetrical about the radial intermittent groove (111); the number of the radial intermittent grooves (111) and the vertical intermittent grooves (112) are both three, the three radial intermittent grooves (111) are adapted to the three radial loading components (6), and the three vertical intermittent grooves (112) are adapted to the three bone plate clamping and positioning components respectively.

5. The loading device for testing the bending strength and bending stiffness of a bone plate according to claim 1, characterized in that: The clamping and locking mechanism comprises: a second bracket plate (38) slidably connected to the first bracket plate (31), and a locking screw (37) threadedly connecting the first bracket plate (31) and the second bracket plate (38).

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