CN117907116A - U-shaped nail mechanical property testing equipment and method - Google Patents

Abstract

The invention provides a device and a method for testing mechanical properties of a U-shaped nail, which belong to the technical field of mechanical property testing of the U-shaped nail and comprise the following steps: a fixed end clamping part, a rotary end clamping part, a U-shaped nail locking rod, a mechanical arm system and a jig table; the number of the U-shaped nail locking rods is two, the two U-shaped nail locking rods are arranged in opposite directions, and opposite ends are used for fixing two support legs of the U-shaped nail; the opposite ends are respectively fixed by the fixed end clamping part and the rotating end clamping part; the mechanical arm system comprises a mechanical arm body, a U-shaped nail clamping claw and a press bending assembly; the mechanical arm body is used for carrying; the U-shaped nail clamping claw is used for carrying U-shaped nails; the bending component is used for bending the U-shaped nails; the jig table is used for placing the U-shaped nails. The test method is carried out by adopting U-shaped nail mechanical property test equipment. The mechanical property testing equipment and the mechanical property testing method for the U-shaped nails can automatically perform torsion and bending testing on the U-shaped nails, are labor-saving and time-saving, and have relatively higher testing precision.

Description

U-shaped nail mechanical property testing equipment and method

Technical Field

The invention relates to the technical field of mechanical property testing of staples, in particular to a device and a method for testing mechanical property of a staple.

Background

The U-shaped nail is a medical instrument for orthopedic surgery and is mainly used for fracture fixation and bone reconstruction surgery. The high-strength stainless steel or titanium alloy material is adopted for manufacturing the high-strength stainless steel or titanium alloy material, and has good biocompatibility and corrosion resistance. The U-shaped nail has the characteristics of simple structure, convenient operation and firm fixation. The fracture fixing device is unique in shape design and U-shaped, and can effectively fix the fracture part and provide stable support. The design of the staple allows it to accommodate different bone morphologies and fracture types, providing a personalized treatment regimen.

In clinical practice, the staples are more subjected to bending load and torsion load, and the adverse events generated after implantation are often fracture or expansion, so that certain requirements on the mechanical properties of the staples are required, and a set of standard tests are required to be performed in vitro in order to ensure the safety of the staples after implantation into a human body. Therefore, the invention designs an automatic device and method for testing mechanical properties of the U-shaped nails, which can automatically realize the torsion and bending property test of the U-shaped nails and can adapt to the U-shaped nails with various specifications and types and various lengths and widths.

Disclosure of Invention

The invention aims to provide a device and a method for testing mechanical properties of a U-shaped nail.

In order to solve the technical problems, the aim of the invention is realized as follows:

a staple mechanical property testing device comprising: a fixed end clamping part, a rotary end clamping part, a U-shaped nail locking rod, a mechanical arm system and a jig table;

the number of the U-shaped nail locking rods is two, the two U-shaped nail locking rods are arranged in opposite directions, and opposite ends are used for fixing two support legs of the U-shaped nail; opposite ends are respectively fixed by the fixed end clamping part and the rotating end clamping part;

The fixed end clamping part comprises a chuck, a clamping and locking assembly, a torque sensor and a fixed end supporting base; the chuck is fixedly arranged on the fixed end supporting base and comprises a plurality of clamping jaws, and the clamping jaws are used for clamping the U-shaped nail locking rod; the clamping and locking assembly is used for driving the clamping jaw to move; the torque sensor is used for detecting the torque exerted on the chuck;

The rotary end clamping part comprises a chuck, a clamping and locking assembly, an angle sensor, a servo motor and a rotary end fixing base; the chuck is rotationally arranged on the rotating end fixed base and is driven to rotate by the servo motor; the angle sensor is used for detecting the rotation angle of the chuck;

The U-shaped nail locking rod comprises a locking rod body, an electromagnetic coil, magnetorheological fluid and a centering sensor; one end of the locking rod body is provided with a strip groove; the magnetorheological fluid is arranged in the strip groove; the electromagnetic coils are arranged on two sides of the locking rod body and correspond to the magnetorheological fluid; the centering sensor is arranged on the end face of the locking rod body to detect whether the two U-shaped nail locking rods deform or not;

The mechanical arm system comprises a mechanical arm body, a U-shaped nail clamping claw, a press bending assembly and a vision module; the mechanical arm body is a six-degree-of-freedom mechanical arm, and the end part of the mechanical arm body is connected with the U-shaped nail clamping claw and the press bending assembly; the U-shaped nail clamping claw is used for carrying a U-shaped nail to and fro between the U-shaped nail locking rod and the jig table; the bending component is used for bending the U-shaped nails; the vision module is used for identifying the U-shaped nails;

the bending component comprises four bending execution pieces and weighing sensors; the bending execution parts are divided into an upper group and a lower group, each group is two, and the two groups can be close under the action of the driving part; the weighing sensor is arranged under one group of press bending execution pieces and is used for detecting press bending load;

the jig table comprises a jig frame, self-repairing hydrogel and a photoelectric sensor; the self-repairing hydrogel is arranged inside the jig frame; staples may be inserted into the self-healing hydrogel; the photoelectric sensor is used for detecting whether the U-shaped nail exists.

On the basis of the above-mentioned scheme and as a preferable scheme of the above-mentioned scheme, the fixed end clamping part is provided with a protective housing.

On the basis of the above aspect and as a preferable aspect of the above aspect, the rotating end clamping part further includes a rotating bearing, a planetary gear set, and a support housing; the support shell is arranged on the rotating end fixed base and covers the outer part of the servo motor; the center of the planetary gear set is in transmission connection with the servo motor, and the outer ring is fixedly connected with the chuck; the rotary bearing is sleeved outside the outer ring of the planetary gear set and is arranged in the supporting shell.

In addition to the above, and as a preferred aspect of the above, the chuck includes a base plate, a housing, and a rotating disk; a boss is arranged at the center of the bottom plate; the rotating disc is rotatably arranged on the top surface of the boss, a spiral groove is formed in one side, far away from the bottom plate, of the rotating disc, and a gear ring is arranged on one surface, facing the bottom plate, of the rotating disc; a plurality of rotating blocks are arranged between the rotating disc and the bottom plate, gear teeth are arranged at the bottom of the rotating blocks and meshed with the gear ring, and the rotating blocks are driven to rotate by the clamping and locking assembly; the back of the claw is provided with a bulge; the bulge is arranged in the spiral groove in a sliding manner; the shell is connected with the bottom plate, covers and locates the rolling disc the boss the turning block is outside, and offer with jack catch looks adaptation's spout.

On the basis of the scheme, as a preferable scheme of the scheme, the clamping and locking assembly comprises a chuck locking fixing plate, a square screwdriver, a locking torque sensor, a coupler and a gear motor; the chuck locking and fixing plate is fixedly arranged outside the shell; the square screwdriver is arranged inside the chuck locking fixing plate, and one end of the square screwdriver is connected with the top of the rotating block; the speed reducing motor is arranged on the chuck locking fixing plate and is connected with the square screwdriver through the coupler, so that the square screwdriver can be driven to rotate; the locking torque sensor is arranged at the upper end of the square screwdriver and used for detecting torque.

On the basis of the above scheme and as a preferable scheme of the above scheme, the U-shaped nail clamping claw comprises a clamping claw bottom plate, an outer shell, a flexible magnetorheological fluid rod and a clamping electromagnetic coil; the outer shell is fixed on the clamping claw bottom plate; the flexible magnetorheological fluid bars are uniformly distributed on the outer shell and comprise outer flexible silicone rubber and inner magnetorheological fluid; the clamping electromagnetic coil is arranged in the outer shell, and an iron core is arranged in the center of the clamping electromagnetic coil.

On the basis of the scheme and as a preferable scheme of the scheme, the bending assembly further comprises a bending bottom plate, a supporting plate and an electric cylinder actuator; the electric cylinder actuator is arranged on the bending bottom plate, and two bending actuators are arranged at the bottom of the electric cylinder actuator; the supporting plate is arranged on the bending bottom plate, and the top surface of the supporting plate is provided with two weighing sensors; the weighing sensor is provided with two bending execution pieces; the clamping claw bottom plate is fixedly connected to the side face of the bending bottom plate.

The mechanical property testing method of the U-shaped nail adopts the mechanical property testing equipment of the U-shaped nail, and comprises the following steps:

S1, preparation before testing: placing the U-shaped nail on a jig table, and inserting two support legs into the self-repairing hydrogel; the mechanical arm body is utilized to drive the bending assembly to fix the two U-shaped nail locking bars on the chucks of the fixed end clamping part and the rotating end clamping part, and the two U-shaped nail locking bars are kept to be centered;

S2, nailing: the mechanical arm system recognizes the position of the U-shaped nail through the visual module, the mechanical arm body drives the U-shaped nail clamping claw to clamp the U-shaped nail to move to the U-shaped nail locking rod, and two support legs of the U-shaped nail are respectively inserted into the strip grooves at the end parts of the two U-shaped nail locking rods; energizing the electromagnetic coil to solidify the magnetorheological fluid in the strip groove to fix the U-shaped nail;

S3, performing torsion test: the chuck of the clamping part of the rotating end is driven by a servo motor to rotate to drive a U-shaped nail locking rod to rotate, and the U-shaped nail locking rod drives one side of a U-shaped nail to rotate, so that the angle sensor and the torque sensor synchronously measure test data; stopping the test when the measured torque suddenly drops below 60%, returning the chuck at the rotary clamping end to the original position, powering off the electromagnetic coil, and replacing the U-shaped nail after the U-shaped nail clamping claw is taken off to carry out repeated test;

s4, performing bending test: after the U-shaped nails are fixed on the U-shaped nail locking bars, the two U-shaped nail locking bars are clamped by the bending execution pieces of the bending assembly, then the chuck of the fixed end clamping part and the chuck of the rotating end clamping part are loosened, the two groups of bending execution pieces are mutually close to apply load until the load measured by the weighing sensor is reduced by 40% compared with the peak load, the test is stopped, and then all the parts are reset to replace the U-shaped nails.

On the basis of the above scheme and as a preferable scheme of the above scheme, in the steps S3 and S4, before the test starts, if the two staple locking bars are deformed, the centering sensor loses the signal, and the mechanical arm system replaces the new staple locking bar.

The beneficial effects of the invention are as follows:

1. The mechanical property testing equipment and the mechanical property testing method for the U-shaped nails can automatically perform torsion and bending testing on the U-shaped nails, are trouble-saving and labor-saving, and have relatively higher testing precision;

2. The U-shaped nails are fixed by the U-shaped nail locking rod, so that the U-shaped nails with various specifications and types can be adapted, and the applicability of the equipment is improved;

3. the magnetorheological fluid is adopted to fix the U-shaped nails, so that the U-shaped nails with various specifications and types can be matched, the fixing effect is good when the U-shaped nails are more attached to the U-shaped nails, and interference abrasion can be avoided;

4. The U-shaped nail can be directly inserted into the self-repairing hydrogel, and after the U-shaped nail is pulled out, the self-repairing hydrogel can be automatically repaired, so that the next U-shaped nail can be placed and inserted.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention.

FIG. 2 is a schematic view of a part of the structure of the present invention.

Fig. 3 is a front view of fig. 2.

Fig. 4 is a schematic structural diagram of a mechanical arm system according to the present invention.

Fig. 5 is an exploded view of the rotary end clamp of the present invention.

Fig. 6 is an exploded view of the clamp lock assembly of the present invention.

FIG. 7 is a schematic view of the staple locking bar and press bending assembly of the present invention.

Fig. 8 is a front view of fig. 7.

FIG. 9 is a schematic view of the staple locking bar of the present invention.

FIG. 10 is a schematic view of the press bending assembly and staple gripper jaw structure of the present invention.

FIG. 11 is a schematic diagram of a fixture table according to the present invention.

Fig. 12 is a schematic view of the chuck according to the present invention.

Fig. 13 is an exploded view of the chuck of the present invention.

Fig. 14 is an exploded view of another perspective of the chuck of the present invention.

In the figure: 1. a fixed end clamping part; 11. a chuck; 12. clamping and locking components; 13. a fixed end supporting base; 14. a claw; 15. a protective housing; 111. a bottom plate; 112. a housing; 113. a rotating disc; 114. a boss; 115. a spiral groove; 116. a gear ring; 117. a rotating block; 118. a protrusion; 121. the chuck locks the fixed plate; 122. a square screwdriver; 123. a shaft coupler; 124. a speed reducing motor;

2. a rotary end clamping part; 21. a servo motor; 22. a rotating end fixing base; 23. a rotating bearing; 24. a planetary gear set; 25. a support housing;

3. A staple locking bar; 31. a locking bar body; 32. an electromagnetic coil; 33. magnetorheological fluid; 34. centering the sensor;

4. A robotic arm system; 41. a robot arm body; 42. a staple gripper jaw; 43. a press bending assembly; 421. a gripper jaw bottom plate; 422. an outer housing; 423. a flexible magnetorheological fluid rod; 431. bending the bottom plate; 432. a support plate; 433. bending an executing piece; 434. an electric cylinder actuator; 435. a weighing sensor;

5. A jig table; 51. a jig frame; 52. self-healing hydrogels.

Detailed Description

The invention will be further described with reference to the drawings and specific examples.

As shown in fig. 1, a mechanical property testing device for a U-shaped nail includes: the clamping device comprises a fixed end clamping part 1, a rotating end clamping part 2, a U-shaped nail locking rod 3, a mechanical arm system 4 and a jig table 5.

As shown in fig. 9, the number of the staple locking bars 3 is two, and the opposite ends are used for fixing two legs of the staple, and the opposite ends are respectively fixed by the fixed end clamping part 1 and the rotating end clamping part 2.

As shown in fig. 1 to 3, the fixed end clamping part 1 includes a chuck 11, a clamping and locking assembly 12, a torque sensor, and a fixed end support base 13. The chuck 11 is fixedly arranged on the fixed end support base 13 and comprises a plurality of clamping jaws 14, and the clamping jaws 14 are movable and are used for clamping the U-shaped nail locking bar 3. The clamp lock assembly 12 is used to drive the jaws 14. The torque sensor is used to detect the torque applied to the chuck 11.

Specifically, two legs are arranged at the bottom of the fixed end support base 13, and one side of the top is fixedly connected with the chuck 11. The fixed end support base 13 is provided with a protective case 15 at the outside thereof, and one end of the protective case abuts against the chuck 11.

As shown in fig. 1 to 3, the rotary end gripping part 2 includes a chuck 11, a clamp-locking assembly 12, an angle sensor, a servo motor 21, and a rotary end fixing base 22. The chuck 11 is rotatably provided on the rotation end fixing base 22 and is driven to rotate by a servo motor 21. The angle sensor is used to detect the rotation angle of the chuck 11. The chucks 11 of the fixed end holding portion 2 and the chucks 11 of the rotating section holding portion 2 hold the end portions of the two staple locking bars 3, respectively, so that the two bars are kept fixed and centered.

As shown in fig. 5, the rotary end clamping portion 2 further includes a rotary bearing 23, a planetary gear set 24, and a support housing 25. The support housing 25 is provided on the rotation end fixing base 22 and covers the outside of the servo motor 21. The center of the planetary gear set 24 is in transmission connection with the servo motor 21, and the outer ring is fixedly connected with the chuck 11. The rotary bearing 23 is sleeved outside the outer ring of the planetary gear set 24 and is arranged in the supporting shell 25. One end of the supporting shell 25 is detachably and fixedly connected with the rotating end fixing base 22, the other end of the supporting shell is sleeved outside the rotating bearing 23, the servo motor 21 is fixed inside the supporting shell 25, an output shaft of the servo motor is connected with the center of the planetary gear set 24, the planetary gear set 24 can be driven to rotate, the chuck 11 is driven to rotate, the chuck 11 rotates to drive the clamped U-shaped nail locking rod 3 to rotate, and torsion testing is achieved.

The chuck 11 and the clamping and locking assembly 12 of the fixed end clamping part 2 are identical in structure with the chuck 11 and the clamping and locking assembly 12 of the rotating section clamping part 2.

Specifically, as shown in fig. 12 to 14, the chuck 11 includes a base plate 111, a housing 112, and a rotary plate 113. The bottom plate 111 is preferably circular, with a boss 114 centrally disposed, and the boss 114 is also circular in shape and smaller in diameter than the bottom plate 111. The rotating disk 113 is rotatably disposed on a side of the boss 114 away from the bottom plate 111, a spiral groove 115 is disposed on a side thereof away from the bottom plate 111, and a gear ring 116 is disposed on a side thereof toward the bottom plate 111. The spiral groove 115 has a spiral structure like mosquito coil, and spirally extends from the center to the edge of the rotation plate 113. The gear teeth of the gear ring 116 are formed as a ring and are arranged near the edge of the rotating disk 113. A plurality of rotating blocks 117 are arranged between the rotating disc 113 and the bottom plate 111, gear teeth are arranged at the bottom of the rotating blocks 117 and meshed with the gear ring 116, and the rotating blocks 117 are driven to rotate by the clamping and locking assembly 12.

The back of the jaws 14 is provided with protrusions 118, the protrusions 118 being fittingly slidably arranged in the spiral grooves 115. When the rotary plate 113 rotates, the pawl 14 is driven to move radially along the rotary plate 113 due to the cooperation of the protrusion 118 and the spiral groove 115.

The casing 112 is detachably connected with the bottom plate 111, covers the outside of the rotating disc 113, the boss 114 and the rotating block 117, and is provided with a chute matched with the claw 14 so that the claw 14 slides. The housing 112 is preferably circular and is laterally apertured to allow the turning block 117 to be coupled to the clamp lock assembly 12.

In this embodiment: as shown in fig. 6, the clamp lock assembly 12 includes a chuck lock fixing plate 121, a square driver 122, a lock torque sensor, a coupling 123, and a reduction motor 124. The chuck locking fixing plate 121 has a cylindrical structure and is fixedly disposed outside the housing 112. The square driver 122 is provided inside the chuck locking fixing plate 121 with one end connected to the top of the turning block 117. Preferably, the bottom of the square screwdriver 122 is provided with a polygonal column structure, which is matched with a groove formed at the top of the turning block 117, so as to realize torque transmission.

The gear motor 124 is disposed at the top of the chuck locking and fixing plate 121, and is in transmission connection with the square screwdriver 122 through the coupling 123 disposed inside the chuck locking and fixing plate 121, so as to drive the square screwdriver 122 to rotate. The locking torque sensor is provided at the upper end of the square screw driver 122 for detecting torque.

During operation, the gear motor 124 drives the square screwdriver 122 to rotate, the square screwdriver 122 drives the rotating block 117 to rotate, the gear teeth at the bottom of the rotating block 117 drive the rotating disc 113 to rotate, the spiral groove 115 of the rotating disc 113 is matched with the protrusions 118 on the back of the clamping jaw 14 to drive the clamping jaw 14 to move, and the clamping chuck 11 clamps and fixes the U-shaped nail locking rod 3.

Illustratively, the number of the clamping jaws 14 on the chuck 11 is three, and the clamping jaws are uniformly distributed along the circumference of the chuck 11; the number of the rotating blocks 117 inside the chuck 11 is three, and the rotating blocks are uniformly distributed along the circumference of the chuck 11.

As shown in fig. 9, the staple locking bar 3 includes a locking bar body 31, an electromagnetic coil 32, a magnetorheological fluid 33, and a centering sensor 34. One end of the locking bar body 31 is provided with a long groove. Magnetorheological fluid 33 is disposed in the elongated recess. The electromagnetic coils 32 are disposed on both sides of the locking bar body 31, and are disposed in correspondence with the magnetorheological fluid 33. A centering sensor 34 is provided at the end face of the locking bar body 31 to detect whether the two staple locking bars 3 are deformed. Preferably, the strip groove is waist-shaped; the U-shaped nail locking rod 3 has a hexagonal prism structure at one end, is convenient for fixing and clamping the chuck 11, has a square column shape at the other end, and is convenient for clamping the centering and bending assembly 43. The waist-shaped long groove is formed by the concave bottom surface of the locking rod body 31 with a square columnar structure and has a certain length so as to be suitable for the U-shaped nails with different sizes. The locking bar body 31 of square columnar structure has offered circular recess in rectangular recess both sides, and solenoid 32 sets up in circular recess, and when solenoid 32 was not circular telegram during operation, magnetorheological fluid 33 was liquid, can place and take out the staple, and after solenoid 32 work, magnetorheological fluid 33 became solid under the magnetic field effect, firmly wrapped up the staple, the test of being convenient for. The centering sensors mounted on the square columnar opposite end surfaces of the two staple locking bars 3 can lose signals after the staple locking bars 3 are frequently used to generate obvious deformation, and the staple locking bars 3 need to be replaced by the mechanical arm system 4.

As shown in fig. 1 and 4, the robotic arm system 4 includes a robotic arm body 41, staple clamping jaw 42, press bending assembly 43, and a vision module.

The robot arm body 41 is a six-degree-of-freedom robot arm, and is connected with a staple gripper jaw 42 and a press bending assembly 43 at the end. The staple holding jaw 42 and the press bending assembly 43 are moved in space.

As shown in fig. 10, the staple gripper 42 is used to carry staples back and forth between the staple lock bar 3 and the jig table 4, and specifically, the staple gripper 42 includes a gripper base 421, an outer case 422, a flexible magnetorheological fluid bar 423, and a gripping solenoid. The outer housing 422 is secured to the gripper jaw plate 421. The flexible magnetorheological fluid rods 423 are uniformly distributed on the outer shell 422 and comprise outer flexible silicone rubber and inner magnetorheological fluid. The clamping solenoid is disposed inside the outer housing 422 with an iron core disposed in the center. When the clamping electromagnetic coil is electrified, the flexible magnetorheological fluid rods 423 are subjected to the action of a magnetic field, the internal magnetorheological fluid is changed from liquid into solid, and simultaneously under the action of the magnetic field, the flexible magnetorheological fluid rods 423 of the array move inwards to generate clamping force on the staples, and the mechanism can be used for stably clamping the staples of various types and specifications. During clamping, the top section of the flexible magnetorheological fluid rod 423 clamps the U-shaped nail cross beam to carry out U-shaped nail conveying.

As shown in fig. 7, 8 and 10, the press bending assembly 43 is used for a staple press bending test and for handling the staple lock bar 3. The press bending assembly 43 includes four press bending actuators 433 and a load cell 435. The bending execution parts 433 are divided into an upper group and a lower group, each group is two, and the two groups can be close to each other under the action of the driving part to realize bending test operation. The load cell 435 is disposed under a set of buckling actuators 433 for detecting buckling load.

Preferably, press bending assembly 43 further includes press bending bottom plate 431, support plate 432, and cylinder actuator 434. The electric cylinder actuator 434 is disposed on the bending bottom plate 431, and two bending actuators 433 are disposed at the bottom of the electric cylinder actuator to drive the bending actuators 433 to descend. The support plate 432 is provided on the press bending bottom plate 431, and the top surface is provided with two load cells 435. The load cell 435 is provided with two buckling actuators 433. Wherein, the bending actuator 43 is L-shaped, and the abutting end is a round roll shaft, so that the sharp object loss is reduced. Optionally, the upper set is connected to a cylinder actuator 434 as the inside actuator for buckling. The lower group is connected with a weighing sensor 435 and serves as an outer support part for bending, and the roll shaft spacing of the upper and lower adjacent bending execution parts is 40mm.

In this embodiment, the gripper bottom plate 421 is fixedly connected to the side of the press bending bottom plate 431, so that the staple gripper 42 and the press bending assembly 43 are connected into a whole, which is convenient for the mechanical arm body 41 to carry.

The vision module is used for identifying the staples, identifying the clamping and placing positions of the staples, and facilitating the positioning and adjusting of the staples by the staple clamping claws 42.

As shown in fig. 11, the jig table 5 includes a jig frame 51, a self-repairing hydrogel 52, and a photoelectric sensor. The self-repairing hydrogel 52 is disposed inside the jig frame 51. Staples can be inserted into the self-healing hydrogel 52, 9. After the staples are pulled out, the hydrogel can be automatically healed, ensuring that the next staple can be placed and inserted. The photoelectric sensor is used for detecting whether a U-shaped nail exists on the jig table 5.

The mechanical property testing equipment for the U-shaped nails can automatically realize the testing of bending property and torsion property of the U-shaped nails. Bending performance is achieved through the bending component 43 of the mechanical arm system 4 to bend the U-shaped nail body, a moment arm converted through equipment and a load value measured by the weighing sensor 435 on the bending component 43 in real time, and bending moment applied to the U-shaped nail is obtained according to a moment formula. The downward bending displacement is achieved by the cylinder actuators 434 on the bending assembly 43 and automatically results in a downward real-time displacement, since the staple size is small, the applied load does not affect the performance and displacement accuracy of the robotic arm. The torsion performance is tested by the chucks 11 on both sides of the apparatus, the fixed end holding portion is kept stationary, the torque generated by torsion is measured by the torque sensor, the rotating end holding portion 2 is rotated by the servo motor 21 and the planetary gear set 24, and the rotation angle is measured.

The mechanical property testing method of the U-shaped nail adopts the mechanical property testing equipment of the U-shaped nail, and comprises the following steps:

S1, preparation before testing: the U-shaped nails are placed on the jig table 5, and two support legs of the U-shaped nails are inserted into the self-repairing hydrogel 52; the mechanical arm body 41 drives the bending assembly 43 to fix the two U-shaped nail locking bars 3 on the chucks 11 of the fixed end clamping part 1 and the rotating end clamping part 2, and keep the two U-shaped nail locking bars 3 centered;

S2, nailing: the mechanical arm system 4 recognizes the position of the U-shaped nail through the vision module, the mechanical arm body 41 drives the U-shaped nail clamping claw 42 to clamp the U-shaped nail to move to the U-shaped nail locking rod 3, and two support legs of the U-shaped nail are respectively inserted into the strip grooves at the end parts of the two U-shaped nail locking rods 3; energizing the electromagnetic coil 32 to solidify the magnetorheological fluid 33 in the strip groove to fix the U-shaped nail;

S3, performing torsion test: the chuck 11 of the rotary end clamping part 2 is driven by the servo motor 21 to rotate to drive a U-shaped nail locking rod 3 to rotate, and the U-shaped nail locking rod 3 drives one side of a U-shaped nail to rotate, and at the moment, the angle sensor and the torque sensor synchronously measure test data; stopping the test when the measured torque drops below 60%, returning the chuck 11 of the rotary clamping end 2 to the original position, powering off the electromagnetic coil 32, and replacing the U-shaped nail after the U-shaped nail clamping claw 42 removes the U-shaped nail to perform repeated test;

S4, performing bending test: after the torsion test is completed, after the staples are fixed on the staple locking bars 3, the two staple locking bars 3 are clamped by the bending execution pieces 433 of the bending assembly 43, then the chucks 11 of the fixed end clamping part 1 and the chucks 11 of the rotating end clamping part 2 are loosened, the two groups of bending execution pieces 433 are mutually close to apply load until the load measured by the weighing sensor 435 is reduced by 40% compared with the peak load, the test is stopped, and then all the components are reset to replace the staples.

In step S3 and step S4, before the test starts, if the two staple locking bars 3 deform, the centering sensor will lose signal, and the mechanical arm system 4 replaces the new staple locking bar 3 to ensure the accuracy of the test.

The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.

Claims (9)

1. A staple mechanical property testing device, comprising: the clamping device comprises a fixed end clamping part (1), a rotating end clamping part (2), a U-shaped nail locking rod (3), a mechanical arm system (4) and a jig table (5);

The number of the U-shaped nail locking rods (3) is two, the two U-shaped nail locking rods are arranged in opposite directions, and opposite ends are used for fixing two support legs of the U-shaped nail; opposite ends are fixed by the fixed end clamping part (1) and the rotating end clamping part (2) respectively;

The fixed end clamping part (1) comprises a chuck (11), a clamping and locking assembly (12), a torque sensor and a fixed end supporting base (13); the chuck (11) is fixedly arranged on the fixed end supporting base (13) and comprises a plurality of clamping jaws (14), and the clamping jaws (14) are used for clamping the U-shaped nail locking rod (3); the clamping and locking assembly (12) is used for driving the clamping jaw (14) to move; the torque sensor is used for detecting the torque exerted on the chuck (11);

the rotary end clamping part (2) comprises a chuck (11), a clamping and locking assembly (12), an angle sensor, a servo motor (21) and a rotary end fixing base (22); the chuck (11) is rotatably arranged on the rotating end fixed base (22) and is driven to rotate by the servo motor (21); the angle sensor is used for detecting the rotation angle of the chuck (11);

The U-shaped nail locking rod (3) comprises a locking rod body (31), an electromagnetic coil (32), magnetorheological fluid (33) and a centering sensor (34); one end of the locking rod body (31) is provided with a strip groove; the magnetorheological fluid (33) is arranged in the strip groove; the electromagnetic coils (32) are arranged on two sides of the locking rod body (31) and are arranged corresponding to the magnetorheological fluid (33); the centering sensor (34) is arranged on the end face of the locking rod body (31) so as to detect whether the two U-shaped nail locking rods (3) deform or not;

The mechanical arm system (4) comprises a mechanical arm body (41), a U-shaped nail clamping claw (42), a bending component (43) and a vision module; the mechanical arm body (41) is a six-degree-of-freedom mechanical arm, and the end part of the mechanical arm body is connected with the U-shaped nail clamping claw (42) and the press bending assembly (43); the U-shaped nail clamping claw (42) is used for carrying a U-shaped nail to and from between the U-shaped nail locking rod (3) and the jig table (4); the bending component (43) is used for a U-shaped nail bending test; the vision module is used for identifying the U-shaped nails;

The press bending assembly (43) comprises four press bending execution pieces (433) and a weighing sensor (435); the bending execution piece (433) is divided into an upper group and a lower group, each group is two, and the two groups can be close under the action of the driving piece; the weighing sensor (435) is arranged under a group of the press bending execution pieces (433) and is used for detecting the press bending load;

The jig table (5) comprises a jig frame (51), self-repairing hydrogel (52) and a photoelectric sensor; the self-repairing hydrogel (52) is arranged inside the jig frame (51); staples may be inserted into the self-healing hydrogel (52); the photoelectric sensor is used for detecting whether the U-shaped nail exists.

2. A staple mechanical property testing device according to claim 1, characterized in that the fixed end clamping part (1) is provided with a protective housing (15).

3. A staple mechanical property testing device according to claim 1, characterized in that the rotating end clamping portion (2) further comprises a rotating bearing (23), a planetary gear set (24) and a supporting housing (25); the supporting shell (25) is arranged on the rotating end fixing base (22) and covers the outside of the servo motor (21); the center of the planetary gear set (24) is in transmission connection with the servo motor (21), and the outer ring is fixedly connected with the chuck (11); the rotary bearing (23) is sleeved outside the outer ring of the planetary gear set (24) and is arranged in the support shell (25).

4. A device for testing mechanical properties of staples according to claim 1, characterized in that said cartridge (11) comprises a bottom plate (111), a housing (112) and a rotating disc (113); a boss (114) is arranged in the center of the bottom plate (111); the rotating disc (113) is rotatably arranged on the top surface of the boss (114), a spiral groove (115) is formed in one side, far away from the bottom plate (111), of the rotating disc, and a gear ring (116) is arranged on one side, facing the bottom plate (111); a plurality of rotating blocks (117) are arranged between the rotating disc (113) and the bottom plate (111), gear teeth are arranged at the bottoms of the rotating blocks (117) and meshed with the gear ring (116), and the rotating blocks (117) are driven to rotate by the clamping and locking assembly (12); the back of the claw (14) is provided with a bulge (118); the protrusion (118) is slidably arranged in the spiral groove (115); the shell (112) is connected with the bottom plate (111), covers the rotating disc (113), the boss (114) and the rotating block (117) and is provided with a sliding groove matched with the clamping jaw (14).

5. The mechanical property testing device for a staple according to claim 4, wherein the clamping and locking assembly (12) comprises a chuck locking and fixing plate (121), a square screwdriver (122), a locking torque sensor, a coupler (123) and a speed reducing motor (124); the chuck locking fixing plate (121) is fixedly arranged outside the shell (112); the square screwdriver (122) is arranged inside the chuck locking fixing plate (121), and one end of the square screwdriver is connected with the top of the rotating block (117); the speed reducing motor (124) is arranged on the chuck locking fixing plate (121), is connected with the square screwdriver (122) through the coupler (123) and can drive the square screwdriver (122) to rotate; the locking torque sensor is arranged at the upper end of the square screwdriver (122) and is used for detecting torque.

6. A staple mechanical property testing device according to claim 1, wherein the staple clamping jaw (42) comprises a clamping jaw base plate (421), an outer housing (422), a flexible magnetorheological fluid rod (423) and a clamping electromagnetic coil; the outer shell (422) is fixed on the clamping claw bottom plate (421); the flexible magnetorheological fluid rods (423) are uniformly distributed on the outer shell (422) and comprise outer flexible silicone rubber and inner magnetorheological fluid; the clamping electromagnetic coil is arranged inside the outer shell (422), and an iron core is arranged in the center.

7. The staple mechanical property testing device of claim 6, wherein the press bending assembly (43) further comprises a press bending bottom plate (431), a support plate (432) and an electric cylinder actuator (434); the electric cylinder actuator (434) is arranged on the bending bottom plate (431), and two bending actuators (433) are arranged at the bottom of the electric cylinder actuator; the supporting plate (432) is arranged on the bending bottom plate (431), and the top surface of the supporting plate is provided with two weighing sensors (435); two bending execution pieces (433) are arranged on the weighing sensor (435); the clamping claw bottom plate (421) is fixedly connected to the side face of the bending bottom plate (431).

8. A method for testing mechanical properties of a staple, characterized in that a device for testing mechanical properties of a staple according to any one of claims 1 to 7 is used, comprising the steps of:

s1, preparation before testing: placing the U-shaped nails on a jig table (5), and inserting two support legs into the self-repairing hydrogel (52); the mechanical arm body (41) is utilized to drive the bending assembly (43) to fix the two U-shaped nail locking bars (3) on the chucks (11) of the fixed end clamping part (1) and the rotating end clamping part (2), and the two U-shaped nail locking bars (3) are kept to be centered;

S2, nailing: the mechanical arm system (4) identifies the positions of the U-shaped nails through the visual module, the mechanical arm body (41) drives the U-shaped nail clamping claws (42) to clamp the U-shaped nails to move to the U-shaped nail locking bars (3), and two support legs of the U-shaped nails are respectively inserted into strip grooves at the end parts of the two U-shaped nail locking bars (3); energizing the electromagnetic coil (32) to solidify the magnetorheological fluid (33) in the strip groove to fix the U-shaped nail;

S3, performing torsion test: the chuck (11) of the rotary end clamping part (2) is driven by the servo motor (21) to rotate to drive a U-shaped nail locking rod (3) to rotate, and the U-shaped nail locking rod (3) drives one side of the U-shaped nail to rotate, so that the angle sensor and the torque sensor synchronously measure test data; stopping the test when the measured torque suddenly drops below 60%, returning the chuck (11) of the rotary clamping end (2) to the original position, switching off the electromagnetic coil (32), and replacing the U-shaped nail after the U-shaped nail clamping claw (42) takes off the U-shaped nail to carry out repeated test;

S4, performing bending test: after the U-shaped nails are fixed on the U-shaped nail locking bars (3), the two U-shaped nail locking bars (3) are clamped by using the bending execution pieces (433) of the bending assembly (43), then the chuck (11) of the fixed end clamping part (1) and the chuck (11) of the rotating end clamping part (2) are loosened, the two groups of bending execution pieces (433) are mutually close to apply load until the load measured by the weighing sensor (435) is reduced by 40% compared with the peak load, the test is stopped, and then all parts are reset to replace the U-shaped nails.

9. The method according to claim 8, wherein in the steps S3 and S4, if the two staple locking bars (3) are deformed before the start of the test, the centering sensor loses the signal, and the mechanical arm system (4) replaces the new staple locking bar (3).