CN210293949U - Mechanical property testing tool for special-shaped bone fracture plate - Google Patents
Mechanical property testing tool for special-shaped bone fracture plate Download PDFInfo
- Publication number
- CN210293949U CN210293949U CN201921115607.9U CN201921115607U CN210293949U CN 210293949 U CN210293949 U CN 210293949U CN 201921115607 U CN201921115607 U CN 201921115607U CN 210293949 U CN210293949 U CN 210293949U
- Authority
- CN
- China
- Prior art keywords
- detected
- bone fracture
- coaptation board
- briquetting
- fracture plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000012360 testing method Methods 0.000 title claims abstract description 55
- 208000010392 Bone Fractures Diseases 0.000 title claims description 52
- 230000002159 abnormal effect Effects 0.000 claims abstract description 12
- 238000009434 installation Methods 0.000 claims abstract description 7
- 210000000988 bone and bone Anatomy 0.000 claims description 25
- 238000010998 test method Methods 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 12
- 238000007689 inspection Methods 0.000 abstract description 4
- 238000001514 detection method Methods 0.000 abstract description 2
- 238000005452 bending Methods 0.000 description 25
- 238000006073 displacement reaction Methods 0.000 description 10
- 230000003068 static effect Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000009661 fatigue test Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004484 Briquette Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 235000001968 nicotinic acid Nutrition 0.000 description 1
- 230000000399 orthopedic effect Effects 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Images
Landscapes
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The utility model discloses a mechanical properties test harness of abnormal shape coaptation board belongs to medical instrument and detects technical field, and this test harness is including fixing base, briquetting and the pressure head that the cooperation was used, be provided with on the lateral wall of fixing base and be used for the installation to be detected a plurality of mounting holes of coaptation board, can satisfy different forms's abnormal shape coaptation board, the briquetting is installed and is used for transmitting the loading force to being detected the coaptation board in one side that is detected the coaptation board tip, the pressure head sets up in the top of briquetting and exerts force to the briquetting in the testing process. The utility model discloses the technical scheme of example carries out scientific, accurate detection to the mechanical properties of abnormal shape coaptation board, has filled the blank of the special test instrument of abnormal shape coaptation board mechanical properties test, has important meaning to medical instrument inspection field.
Description
Technical Field
The utility model belongs to the technical field of medical instrument inspection, specific mechanical properties test harness of abnormal shape coaptation board that says so is applicable to the test of abnormal shape coaptation board mechanical properties.
Background
The bone fracture plate is a medical instrument with high risk in national key supervision, is a fixing device which is designed according to the shape of human skeleton and bionics, and is generally used for treating orthopedic diseases which are caused by various reasons and need to be fixed and treated. The quality inspection before the use of the medicine is very important and is closely related to the physical rehabilitation condition of patients. The adverse events of clinically suspicious medical instruments are mainly manifested by steel plate fracture, bending, looseness and the like.
Therefore, the mechanical properties of the bone plate, such as fatigue strength, have an important influence on the usability of the bone plate, and the mechanical properties of the bone plate need to be strictly detected in order to ensure the reliability of the use of the bone plate.
The bone fracture plate comprises a straight-strip-shaped bone fracture plate with a regular shape and a special-shaped bone fracture plate with an irregular shape, the special-shaped bone fracture plate is mainly used for fixing bones at positions such as joints, at present, for the straight-strip-shaped bone fracture plate, a test method for the mechanical property of the straight-strip-shaped bone fracture plate is specified by related industry standards, but no test method and corresponding test equipment for the mechanical property of the special-shaped bone fracture plate exist in the prior art.
In summary, it is an urgent need to solve the problem of designing a tool and a method for testing the mechanical properties of a special-shaped bone fracture plate so as to scientifically and accurately detect the mechanical properties of the special-shaped bone fracture plate.
SUMMERY OF THE UTILITY MODEL
In order to solve the deficiencies in the prior art, the utility model aims to provide a mechanical properties test harness of abnormal shape coaptation board to realize scientific, accurate detection to the mechanical properties of abnormal shape coaptation board.
The utility model provides a technical scheme that its technical problem adopted does:
the utility model provides a mechanical properties test harness of abnormal shape coaptation board, fixing base, briquetting and pressure head including the cooperation is used, be provided with the mounting hole that is used for the installation to be detected the coaptation board on the lateral wall of fixing base, the briquetting is installed and is used for transmitting the loading force to being detected the coaptation board in the one side that is detected the coaptation board tip, the pressure head sets up in the top of briquetting and applys the loading force to the briquetting in the test process.
Furthermore, the mounting holes are provided with a plurality of holes which are longitudinally arranged on the side wall of the fixed seat in parallel.
Further, the fixing base is hollow and cylindrical, and a mounting flange is arranged at the bottom end of the fixing base.
Furthermore, one side of the pressing block connected with the bone fracture plate to be detected is provided with an arc-shaped surface matched with the bone fracture plate to be detected.
Furthermore, the rest side surfaces of the pressing block are all planes.
Further, the pressure head is flat.
Compared with the prior art, the beneficial effects of the utility model are that:
1. the utility model discloses the test harness of example carries out mechanical properties's test to abnormal shape coaptation board, has filled the blank of the special test instrument of abnormal shape coaptation board mechanical properties test, has important meaning to medical instrument inspection field.
2. The utility model discloses the test harness of example, the mounting hole vertically is provided with a plurality ofly on the lateral wall of fixing base side by side, is applicable to the coaptation board of the multiple different models of installation, and application scope is wide.
3. The utility model discloses the test harness of example, fixing base are hollow cylindricly, and the bottom of fixing base is provided with mounting flange, alleviates the quality of harness, reduces the consumptive material of harness, and the harness of being convenient for simultaneously gets operations such as putting, installation.
4. The utility model discloses the test harness of example, briquetting with detect one side that the coaptation board links to each other set up to with the arcwall face that is detected the coaptation board adaptation, suitability between them is better, do benefit to the accuracy of assurance test result.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
fig. 1 is a schematic structural view of the assembled test harness according to the embodiment of the present invention;
fig. 2 is a schematic structural diagram of a pressure head of a test harness according to an embodiment of the present invention;
fig. 3 is a schematic structural view of a fixing seat of a test harness according to an embodiment of the present invention;
fig. 4 is a schematic cross-sectional structural view of a cylindrical portion of a fixing seat of a testing harness according to an embodiment of the present invention;
FIG. 5 is a bottom view of FIG. 4;
FIG. 6 is a schematic structural view of the assembled pressing block and the bone fracture plate to be detected according to the embodiment of the present invention;
fig. 7 is a force displacement curve diagram during the testing process of the embodiment of the present invention.
In the figure: the bone fracture plate comprises a fixed seat 1, a mounting hole 11, a screw hole 12, a pressing block 2, a pressing head 3, a detected bone fracture plate 4 and a fixing hole 41.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention.
The components of the embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
As shown in fig. 1, an embodiment of the utility model provides a heterotypic coaptation board mechanical properties test harness, fixing base 1, briquetting 2 and pressure head 3 including the cooperation is used, be provided with on the lateral wall of fixing base 1 and be used for the installation to be detected the mounting hole 11 of coaptation board 4, briquetting 2 is installed and is used for transmitting the loading force to being detected the coaptation board 4 in the one side that is detected the 4 tip of coaptation board, pressure head 3 sets up in the top of briquetting 2 and applys the loading force to briquetting 2 in the test procedure.
As shown in fig. 3, the mounting holes 11 are provided in plural, and the plural mounting holes 11 are longitudinally arranged in parallel on the side wall of the fixing base 1. The mounting holes 11 are suitable for mounting various bone fracture plates of different models, the application range is wide, the mounting holes 11 are screw holes, and the detected bone fracture plate 4 can be mounted on the fixing seat 1 by fastening screws during specific mounting.
The fixing seat 1 is hollow and cylindrical, and a mounting flange used for mounting the fixing seat 1 on a test bed is arranged at the bottom end of the fixing seat 1. As shown in fig. 4 and 5, a screw hole 12 for connecting the fixing base 1 with other installation parts may be further provided at the bottom end of the side wall of the fixing base 1. This kind of structural style can alleviate the quality of harness, reduces the consumptive material of harness, and the operation such as getting of the harness of being convenient for simultaneously is put, is installed.
As shown in fig. 6, one side of the pressing block 2 connected with the bone fracture plate 4 to be detected is set to be an arc-shaped surface matched with the bone fracture plate 4 to be detected, and the other side surfaces of the pressing block 2 are flat surfaces. The structure makes the pressing block 2 and the bone fracture plate 4 to be detected have better adaptability and more accurate transmission of the acting force, and the pressing block 2 of the embodiment adopts a polyurethane block which conforms to ASTMF 1839.
As shown in fig. 2, the indenter 3 of the present example is flat, and the indenter 3 is longitudinally loaded on the compact 2 as shown in fig. 1 during the test, thereby preventing stress concentration from occurring on the compact 2 during the loading.
The method for carrying out the static mechanical test on the special-shaped bone fracture plate by using the test harness of the embodiment comprises the following steps:
the indenter 3 is mounted on the testing machine;
the pressing block 2 is arranged at one end of the detected bone fracture plate 4 with arc-shaped bending, the other end of the detected bone fracture plate 4 is arranged at a proper position of the fixed seat 1, and the fixed seat 1 is arranged on a test bed of the testing machine; specifically, the connecting pieces between the pressing block 2 and the detected bone fracture plate 4 and between the detected bone fracture plate 4 and the fixed seat 1 can adopt screws;
the testing machine is started, the pressure head 3 applies external load to the pressing block 2 until the detected bone fracture plate 4 or the matched screw is damaged;
and acquiring the static bending strength of the bone fracture plate 4 to be detected.
Specifically, when the bending stiffness is tested, the pressure head applies an external load to the pressing block and the external load is gradually increased at a control rate of 10mm/min, a force displacement curve is shown in fig. 7, and the maximum slope (N/m) of the linear elastic part on the force displacement curve is the bending stiffness.
When the bending strength is tested, the pressing block generates a bending moment with 0.2% deviation displacement, and the 0.2% deviation displacement q is calculated by the following formula:
q＝0.002*L，
in the formula: l is the moment arm;
if the detected bone fracture plate is fractured before reaching the specified load, the bending moment during fracture is the bending strength; otherwise, obtaining the bending strength according to the yield load and the force arm of the detected bone fracture plate, which is as follows:
if the bone plate being tested fractures before the force displacement curve intersects the offset straight line BC, the buckling stiffness is calculated by:
bending stiffness Fmax L,
in the formula: fmax is crushing force; l is the moment arm.
Otherwise, as shown in fig. 7, on the force displacement graph, from the initial (linear) part of the load displacement curve, a best fit straight line OM is drawn, and the bending stiffness of the angle fixator is calculated by calculating the slope of the straight line OM, specifically:
on the force displacement diagram, OB is plotted so that OB equals q, then a straight line BC is plotted parallel to OM, and the intersection of the force displacement curve and the straight line BC is plotted as the yield load.
And calculating the bending strength of the detected bone fracture plate according to the following formula:
bending stiffness P x L,
in the formula: p-yield load; l is the moment arm.
The method for carrying out dynamic fatigue mechanical test on the special-shaped bone fracture plate by using the test harness of the embodiment comprises the following steps:
the pressure head 3 is arranged on a tension-torsion fatigue testing machine;
the pressing block 2 is arranged at one end of the detected bone fracture plate 4 with arc-shaped bending, the other end of the detected bone fracture plate 4 is arranged at a proper position of the fixed seat 1, and the fixed seat 1 is arranged on a test bed of the tension-torsion fatigue testing machine; the specific connection mode can be the same as that of static mechanical test;
the indenter 3 applies an initial fatigue load to the briquette 2 to perform a fatigue cycle for a predetermined time 10 when the test is stopped6A cycle period or more; a counter can be connected to the testing machine to record the fatigue cycle times;
in the absence of experience, 75%, 50% and 25% of the bending strength of the bone plate, as measured by static mechanical testing, corresponds to the initial fatigue load. At the same time, the maximum difference between the load levels at which fatigue strength is measured cannot exceed 10% of the flexural strength measured by the static bending test. The method for measuring the fatigue strength of the bone fracture plate comprises a lifting method and a correction lifting method, and the fatigue life and the fatigue strength of the bone fracture plate to be measured are obtained.
Taking the load force of the tested bone fracture plate with the static maximum bending strength as 1000N as an example, the lifting method and the correction lifting method for measuring the fatigue strength of the bone fracture plate are described as follows:
firstly, setting 75% of the loading force of the static maximum bending strength as the initial fatigue load, in this embodiment, performing fatigue cycle for setting the initial fatigue load of 750N, after the cycle setting period, if the bone plate to be detected is still intact, increasing a certain load, and performing fatigue cycle again, wherein the maximum difference between the loading levels for measuring the fatigue strengths cannot exceed 10% of the bending strength measured by the static bending test, that is, the increased load cannot exceed 10% of the bending strength measured by the static bending test, specifically, in this embodiment, the increased fatigue load cannot exceed 10% of 1000N, that is, cannot exceed 100N, taking the example of 10% load increase each time as an example, after 75% of the initial fatigue load fatigue cycle is completed, if the bone plate to be detected is still intact, applying 85% of the fatigue load to perform fatigue cycle, after the set period of circulation, observing whether the detected bone plate is damaged or not, and if the detected bone plate is still intact, continuously increasing by at most 10% until the detected bone plate is damaged.
Generally, after 75% of the initial fatigue load cycle setting period, most of the tested bone plates are damaged, at this time, 50% of the initial fatigue load is usually selected for fatigue cycle, still referring to the above steps, if the tested bone plates are complete after 50% of the initial fatigue load cycle is completed, 10% of the fatigue load is increased, namely 60% of the fatigue load is applied for fatigue cycle again, after the cycle setting period, whether the tested bone plates are damaged is observed, and if the tested bone plates are complete, the increase is continued to be at most 10% until the tested bone plates are damaged.
If the tested bone plate is damaged after 50% of the initial fatigue load cycle setting period, then the 25% of the initial fatigue load is usually selected for fatigue cycle, still referring to the above steps, if the tested bone plate is complete after the 25% of the initial fatigue load cycle is completed, then the fatigue load is increased by 10%, namely 35% of the fatigue load is applied for fatigue cycle again, after the cycle setting period, whether the tested bone plate is damaged is observed, and if the tested bone plate is complete, the increase is continued to be at most 10% until the tested bone plate is damaged.
In the test process of increasing the fatigue load, if the detected bone fracture plate is damaged after a certain fatigue cycle period is finished, the fatigue life and the fatigue strength of the detected bone fracture plate are obtained according to the maximum fatigue load value which is not damaged in the previous cycle.
If the condition that the detected bone fracture plate is damaged after the initial fatigue load is applied for a set period of a cycle, the detected bone fracture plate is kept intact after the initial fatigue load is reduced and the test is carried out again, when the difference value between the fatigue load and the initial fatigue load of the damaged detected bone fracture plate is not more than 10% of the bending strength measured by the static bending test, if the detected bone fracture plate is not damaged after the fatigue cycle, the fatigue life and the fatigue strength of the detected bone fracture plate are determined by the fatigue load in the fatigue cycle period, and the fatigue load does not need to be increased any more.
The utility model discloses when implementing, the selection of foretell initial fatigue load is not limited to the numerical value of embodiment, also can select other numerical values according to actual conditions.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be understood by those skilled in the art that the scope of the present invention is not limited to the specific combination of the above-mentioned features, but also covers other embodiments formed by any combination of the above-mentioned features or their equivalents without departing from the spirit of the present invention. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Besides the technical features described in the specification, other technical features are known to those skilled in the art, and further description of the other technical features is omitted here in order to highlight the innovative features of the present invention.
Claims (6)
1. The utility model provides a mechanical properties test harness of abnormal shape coaptation board, its characterized in that, including fixing base, briquetting and the pressure head that the cooperation was used, be provided with the mounting hole that is used for the installation to be detected the coaptation board on the lateral wall of fixing base, the briquetting is installed and is used for transmitting the loading power to being detected the coaptation board in the one side that is detected the coaptation board tip, the pressure head sets up in the top of briquetting and applys the loading power to the briquetting in the test procedure.
2. The mechanical property testing tool for the special-shaped bone plate as claimed in claim 1, wherein a plurality of mounting holes are formed in the fixing base, and the plurality of mounting holes are longitudinally arranged on the side wall of the fixing base in parallel.
3. The mechanical property testing tool for the special-shaped bone fracture plate according to claim 1, wherein the fixing seat is in a hollow cylindrical shape, and a mounting flange is arranged at the bottom end of the fixing seat.
4. The mechanical property testing tool for the special-shaped bone fracture plate according to claim 1, wherein one side of the pressing block connected with the bone fracture plate to be detected is provided with an arc-shaped surface matched with the bone fracture plate to be detected.
5. The mechanical property testing tool for the special-shaped bone plate according to claim 4, wherein the rest side surfaces of the pressing block are flat surfaces.
6. The mechanical property testing tool for the special-shaped bone plate as claimed in claim 1, wherein the pressure head is flat.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921115607.9U CN210293949U (en) | 2019-07-17 | 2019-07-17 | Mechanical property testing tool for special-shaped bone fracture plate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921115607.9U CN210293949U (en) | 2019-07-17 | 2019-07-17 | Mechanical property testing tool for special-shaped bone fracture plate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210293949U true CN210293949U (en) | 2020-04-10 |
Family
ID=70102638
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921115607.9U Expired - Fee Related CN210293949U (en) | 2019-07-17 | 2019-07-17 | Mechanical property testing tool for special-shaped bone fracture plate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210293949U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110296903A (en) * | 2019-07-17 | 2019-10-01 | 山东省医疗器械产品质量检验中心 | Special-shaped bone plate Mechanics Performance Testing harness and test method |
-
2019
- 2019-07-17 CN CN201921115607.9U patent/CN210293949U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110296903A (en) * | 2019-07-17 | 2019-10-01 | 山东省医疗器械产品质量检验中心 | Special-shaped bone plate Mechanics Performance Testing harness and test method |
| CN110296903B (en) * | 2019-07-17 | 2024-05-24 | 山东省医疗器械产品质量检验中心 | Mechanical property testing harness and testing method for special-shaped bone fracture plate |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Cunningham et al. | Biomechanical measurement of fracture healing | |
| Lally et al. | Elastic behavior of porcine coronary artery tissue under uniaxial and equibiaxial tension | |
| CN103025238B (en) | System and method for determining structural characteristics of an object | |
| CN103308444B (en) | Bone implanted metal and tool cated metal material pick-up unit in serviceable life | |
| CN110296903B (en) | Mechanical property testing harness and testing method for special-shaped bone fracture plate | |
| US4649933A (en) | Apparatus and method for monitoring bone-fracture union | |
| CN210293949U (en) | Mechanical property testing tool for special-shaped bone fracture plate | |
| EP1433445A1 (en) | Apparatus for intraoperative measurement of the mechanical stability of an endoprosthesis implanted in a bone | |
| Yoganandan et al. | Thoracic deformation contours in a frontal impact | |
| Cheal et al. | Stress analysis of a simplified compression plate fixation system for fractured bones | |
| Mešić et al. | Numerical and experimental stress analysis of an external fixation system | |
| Rajamanthrilage et al. | Measuring orthopedic plate strain to track bone healing using a fluidic sensor read via plain radiography | |
| CN109009320B (en) | Knee joint osteotomy angle measuring device | |
| CN212228619U (en) | Fatigue performance test aid for femoral component with handle | |
| Soltész | The influence of loading conditions on the life-times in fatigue testing of bone cements | |
| Ogrodnik et al. | A fracture movement monitoring system to aid in the assessment of fracture healing in humans | |
| US20210045636A1 (en) | Methods for establishing the stiffness of a bone using mechanical response tissue analysis | |
| Shiba et al. | Fatigue properties of the Hoffmann-Vidal external fixation apparatus | |
| EP2422707A2 (en) | Evaluation of reflected time-energy profile for evaluation of damping capacity, osseointegration and density | |
| Alberts et al. | A biologic model for assessment of osseous strain patterns and plating systems in the human maxilla | |
| AT506364B1 (en) | DEFORMATION TO BONE IMPLANT ARRANGEMENTS | |
| Churches et al. | Fracture healing assessment with external fixation | |
| US11484248B2 (en) | Systems and methods for establishing the stiffness of a ulna bone using mechanical response tissue analysis | |
| CN118168949A (en) | Bone fracture plate test device | |
| CN111227920A (en) | Internal fixation device for fracture |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200410 |