CN213365899U - Model teaching aid for mathematical probability teaching - Google Patents
Model teaching aid for mathematical probability teaching Download PDFInfo
- Publication number
- CN213365899U CN213365899U CN202022810857.3U CN202022810857U CN213365899U CN 213365899 U CN213365899 U CN 213365899U CN 202022810857 U CN202022810857 U CN 202022810857U CN 213365899 U CN213365899 U CN 213365899U
- Authority
- CN
- China
- Prior art keywords
- plate
- base
- fixedly connected
- motor
- experiment
- 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
- 238000002474 experimental method Methods 0.000 claims abstract description 35
- 244000309464 bull Species 0.000 claims abstract description 10
- 238000009826 distribution Methods 0.000 claims abstract description 9
- 239000002023 wood Substances 0.000 claims description 5
- 238000009434 installation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000012271 agricultural production Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000003028 elevating effect Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Landscapes
- Instructional Devices (AREA)
Abstract
The utility model discloses a model teaching aid for mathematical probability teaching, which comprises a base, wherein the top of the base is provided with a telescopic mechanism, a support plate, a random distribution model mechanism and an estimation mechanism, the bottom of the base is provided with universal wheels, and an anti-skid mechanism is arranged inside the base; telescopic machanism includes first expansion bracket, second expansion bracket, third expansion bracket, fourth expansion bracket, first board, the second of receiving is pressed board, motor base, first motor, screw rod, nut and guard plate, random distribution model mechanism is including collecting box, experiment box, input pipeline, experiment board, left deflector and right deflector, antiskid mechanism includes second motor, bull stick, gear, rack, antiskid ribbed tile, through first motor control, makes the backup pad drive the teaching aid and carries out the lift work, and the teacher of various heights of being convenient for uses, sets up the universal wheel, makes this teaching aid can be towards the student of various directions.
Description
Technical Field
The utility model relates to a teaching aid technical field specifically is a model teaching aid for mathematical probability teaching.
Background
The probability theory is a branch of mathematics, which researches the quantity rule of random phenomena, on one hand, the probability theory has own unique concept and method, on the other hand, the probability theory is closely connected with other mathematical branches, the probability theory is an important component of modern mathematics, the wide application of the probability theory almost extends to all scientific and technical fields, such as weather forecast, earthquake forecast, product sampling survey, various departments of industrial and agricultural production and national economy, and probability factors such as interference resistance, resolution ratio and the like which can be used for improving signals in communication engineering are relatively abstract concepts, and in the course of university probability theory, students can understand and master more easily if a probability teaching aid is used for demonstrating and cooperating with explanation.
At present, most of model teaching aids for mathematical probability teaching in the market are of fixed structures, the height of the model teaching aids cannot be changed, and teachers with different heights are inconvenient to use.
Disclosure of Invention
An object of the utility model is to provide a model teaching aid for mathematical probability teaching to solve the problem that proposes in the above-mentioned background art.
In order to achieve the above object, the utility model provides a following technical scheme: a model teaching aid for mathematical probability teaching comprises a base, wherein a telescopic mechanism, a supporting plate, a random distribution model mechanism and a fixing mechanism are arranged at the top of the base, universal wheels are arranged at the bottom of the base, and an anti-skidding mechanism is arranged inside the base;
the telescopic mechanism comprises a first telescopic frame, a second telescopic frame, a third telescopic frame, a fourth telescopic frame, a first pressure receiving plate, a second pressure receiving plate, a motor base, a first motor, a screw rod, a nut and a protection plate, wherein the bottom of a supporting plate at one end of the first telescopic frame is hinged, the other end of the first telescopic frame is hinged with the top of the first pressure receiving plate, one end of the second telescopic frame is hinged with the bottom of the first pressure receiving plate, the other end of the second telescopic frame is hinged with the top of the base, the bottom of a supporting plate at one end of the third telescopic frame is hinged, the other end of the third telescopic frame is hinged with the top of the second pressure receiving plate, one end of the fourth telescopic frame is hinged with the bottom of the second pressure receiving plate, the other end of the fourth telescopic frame is hinged with the top of the base, the motor base is fixedly connected to the right side of the second pressure receiving plate, the first motor is fixedly connected to the top of the motor, one end of the screw is fixedly connected to the rotating end of the motor, the other end of the screw penetrates through the second pressure receiving plate and the first pressure receiving plate and extends to the left side of the first pressure receiving plate, the nut is fixedly connected to the left side of the first pressure receiving plate and is in threaded connection with the screw, and the protection plate is fixedly connected to the left side of the screw;
the random distribution model mechanism comprises a collection box, an experiment box, a throwing pipeline, an experiment plate, a left guide plate and a right guide plate, wherein the collection box is fixedly connected to the top of a support plate, the experiment box is fixedly connected to the middle of the top of the collection box, the throwing pipeline is fixedly connected to the top of the experiment box, the bottom of the throwing pipeline penetrates through the experiment box and extends to the inside of the experiment box, the experiment plate is fixedly connected to the inside of the experiment box, the experiment plate is arranged below the throwing pipeline and is horizontally arranged, the left guide plate is fixedly connected to the bottom of the inside of the experiment box and is arranged at the left lower part of the experiment plate, and the right guide plate is fixedly connected to the bottom of the inside of the experiment box and is arranged at the right lower part of the experiment plate;
anti-skidding mechanism includes second motor, bull stick, gear, rack, antiskid ribbed tile, second motor fixed connection is in the inside of base, bull stick fixed connection is in the rotation end of second motor, the fixed cover of gear is on the surface of bull stick, rack and gear engagement, and the bottom of rack passes the base and extends to the bottom of base, antiskid ribbed tile fixed connection bestows on the bottom of rack.
Fixing mechanism includes first fixed plate, second fixed plate, locating piece, slider and handle, first fixed plate fixed connection is at the top of backup pad, and first fixed plate setting is in the front of collecting the box, second fixed plate fixed connection is at the top of backup pad, and the second fixed plate setting is at the back of collecting the box, be provided with the sliding tray in the second fixed plate, it is provided with first constant head tank to collect the box back, the locating piece is sliding connection in the sliding tray, and the one end and the first constant head tank sliding contact of locating piece, the second constant head tank is seted up on the locating piece surface, the slider is sliding connection in the sliding tray, and the one end and the second constant head tank sliding contact of slider, handle fixed connection is on the surface of slider, and the one end of handle passes the second fixed plate and extends to the back of second fixed plate.
Preferably, the experiment box is provided with a first opening on the left side and a second opening on the right side.
Preferably, the number of universal wheels is four, and four universal wheels are evenly arranged at the bottom of the base.
Preferably, the antiskid plate is made of a wood plate, and the bottom of the antiskid plate is provided with a plurality of grains.
Preferably, the side surface of the rack is in contact with the base box.
Preferably, the protection plate material is a wood plate, and the side surface of the protection plate is smoothly arranged.
Compared with the prior art, the beneficial effects of the utility model are that: this a model teaching aid for mathematical probability teaching, through first motor control, make the backup pad drive the teaching aid and carry out the elevating work, the teacher of various heights of being convenient for uses, set up the universal wheel, make this a model teaching aid for mathematical probability teaching be convenient for remove and make the teaching aid can be towards the student of various directions, set up anti-skidding mechanism, make this a model teaching aid for mathematical probability teaching can not remove when fixed, prevent that this teaching aid from sliding at uneven highway section and causing the accident, set up the guard plate, prevent that the screw from causing the injury to teacher or student, set up fixed establishment, make the more firm of collection box installation, and make random distribution model convenient to detach and change, be convenient for show more model to the student.
Drawings
FIG. 1 is a front view of the structure of the present invention;
FIG. 2 is a schematic side view of the first expansion bracket and the first compression plate of the present invention;
FIG. 3 is a partially enlarged schematic view of the structure A of the present invention;
fig. 4 is a schematic side view of the structure fixing mechanism of the present invention.
In the figure: the device comprises a base 1, a 2 telescopic mechanism, a 201 first telescopic frame, a 202 second telescopic frame, a 203 third telescopic frame, a 204 fourth telescopic frame, a 205 first pressed plate, a 206 second pressed plate, a 207 motor base, a 208 first motor, a 209 screw rod, a 210 nut, a 211 protection plate, a 3 support plate, a 4 random distribution model mechanism, a 401 collection box, a 402 experiment box, a 403 throwing pipeline, a 404 experiment plate, a 405 left guide plate, a 406 right guide plate, a 5 universal wheel, a 6 anti-skidding mechanism, a 601 second motor, a 602 rotating rod, a 603 gear, a 604 rack, a 605 anti-skidding plate, a 7 fixing mechanism, a 701 first fixing plate, a 702 second fixing plate, a 703 positioning block, a 704 sliding block and a 705 handle.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. 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.
Referring to fig. 1-4, the present invention provides a technical solution: a model teaching aid for mathematical probability teaching comprises a base 1, wherein a telescopic mechanism 2, a supporting plate 3, a randomly distributed model mechanism 4 and a fixing mechanism 7 are arranged at the top of the base 1, the teaching aid 4 is fixedly connected to the top of the supporting plate 3 and is connected with the teaching aid 4 through the supporting plate 3, so that the teaching aid 4 can be conveniently detached and replaced, universal wheels 5 are arranged at the bottom of the base 1, the number of the universal wheels 5 is four, the four universal wheels 5 are uniformly arranged at the bottom of the base 1, the universal wheels 5 are arranged, the model teaching aid for mathematical probability teaching is convenient to move, the teaching aid 4 can face students in various directions, and an anti-skidding mechanism 6 is arranged inside the base 1;
the telescopic mechanism 2 comprises a first telescopic frame 201, a second telescopic frame 202, a third telescopic frame 203, a fourth telescopic frame 204, a first pressure receiving plate 205, a second pressure receiving plate 206, a motor base 207, a first motor 208, a screw 209, a nut 210 and a protection plate 211, wherein one end of the first telescopic frame 201 is hinged with the bottom of the support plate 3, the other end of the first telescopic frame 201 is hinged with the top of the first pressure receiving plate 205, one end of the second telescopic frame 202 is hinged with the bottom of the first pressure receiving plate 205, the other end of the second telescopic frame 202 is hinged with the top of the base 1, one end of the third telescopic frame 203 is hinged with the bottom of the support plate 3, the other end of the third telescopic frame 203 is hinged with the top of the second pressure receiving plate 206, one end of the fourth telescopic frame 204 is hinged with the bottom of the second pressure receiving plate 206, the other end of the fourth telescopic frame 204 is hinged with the top of the base 1, the motor base 207 is fixedly connected to the right side of the second pressure, the first motor 208 is fixedly connected to the top of the motor base 207, one end of the screw rod 209 is fixedly connected to the rotating end of the first motor 208, the other end of the screw rod 209 penetrates through the second pressed plate 206 and the first pressed plate 205 and extends to the left side of the first pressed plate 205, the nut 210 is fixedly connected to the left side of the first pressed plate 205, the nut 210 is in threaded connection with the screw rod 209, the protection plate 211 is fixedly connected to the left side of the screw rod 209, the protection plate 211 is made of a wood plate, the side surface of the protection plate 211 is smoothly arranged, the protection plate 211 is prevented from being injured by the screw rod 209 on teachers or students, the support plate drives the teaching aid to perform lifting work under the control of the first motor 208;
the randomly distributed model mechanism 4 comprises a collecting box 401, an experimental box 402, a throwing pipeline 403, an experimental plate 404, a left guide plate 405 and a right guide plate 406, the collecting box 401 is fixedly connected to the top of the supporting plate 3, the experimental box 402 is fixedly connected to the middle of the top of the collecting box 401, the left side of the experimental box 402 is provided with a first opening and the right side is provided with a second opening, the throwing pipeline 403 is fixedly connected to the top of the experimental box 402, the bottom of the throwing pipeline 403 passes through the experimental box 402 and extends into the experimental box 402, the experimental plate 404 is fixedly connected to the inside of the experimental box 402, the experimental plate 404 is arranged below the throwing pipeline 403 and horizontally arranged, the left guide plate 405 is fixedly connected to the bottom of the inside of the experimental box 402 and arranged below the left of the experimental plate 404, the right guide plate 406 is fixedly connected to the bottom of the inside of the experimental box 402 and arranged below the right of the experimental plate 404, the randomly, students can know the probability more intuitively;
The fixing mechanism 7 comprises a first fixing plate 701, a second fixing plate 702, a positioning block 703, a sliding block 704 and a handle 705, the first fixing plate 701 is fixedly connected to the top of the supporting plate 3, the first fixing plate 701 is arranged on the front side of the collecting box 401, the second fixing plate 702 is fixedly connected to the top of the supporting plate 3, the second fixing plate 702 is arranged on the back side of the collecting box 401, a sliding groove is arranged in the second fixing plate 702, a first positioning groove is arranged on the back side of the collecting box 401, the positioning block 703 is slidably connected in the sliding groove, one end of the positioning block 703 is in sliding contact with the first positioning groove, a second positioning groove is arranged on the surface of the positioning block 703, the sliding block 704 is slidably connected in the sliding groove, one end of the sliding block 704 is in sliding contact with the second positioning groove, the handle 705 is fixedly connected to the surface of the sliding block 704, and one end of the handle 705 passes through the second fixing, set up fixed establishment 7, make the more firm of collecting box 401 installation to make the model mechanism 4 convenient to detach and change of random distribution, be convenient for show more models to the student.
The working principle is as follows: when the model teaching aid for mathematical probability teaching goes up and down, the first motor 208 works, the rotating end of the first motor enables the screw 209 to rotate, so that the nut 210 drives the first pressed plate 205 to move rightwards and simultaneously the second pressed plate 206, the motor base 207 and the first motor 208 move leftwards, the first pressed plate 205 and the second pressed plate 206 move in opposite directions to enable the first expansion bracket 201 and the fourth expansion bracket 204 to rotate anticlockwise and the second expansion bracket 202 and the third expansion bracket 203 to rotate clockwise, so that the support plate 3 drives the teaching aid 4 to go up and down in the same way; when the model teaching aid for mathematical probability teaching moves, the second motor 601 works, and the rotating end of the second motor rotates the rotating rod 602 and the gear 603, so that the rack 604 slides upwards to push the teaching aid 4 to move and fix the teaching aid in the same way;
when the model teaching aid for mathematical probability teaching is used for experiments, table tennis balls are thrown into the throwing channel 403, and after rebounding through the experiment board 404, the table tennis balls randomly enter the left guide plate 405 or the right guide plate 406 and finally enter the collection box 401 to perform probabilistic experiment work;
when the model teaching aid for mathematical probability teaching is installed, the positioning block 703 is slid to the first positioning groove to fix the randomly distributed model mechanism 4, and then the handle 705 is slid to slide the slider 704 to the second positioning groove on the surface of the positioning block 703, so that the randomly distributed model mechanism 4 is completely fixed to complete the fixing work.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. The utility model provides a model teaching aid for mathematical probability teaching, includes base (1), its characterized in that: the top of the base (1) is provided with a telescopic mechanism (2), a support plate (3), a random distribution model mechanism (4) and a fixing mechanism (7), the bottom of the base (1) is provided with universal wheels (5), and an anti-skid mechanism (6) is arranged inside the base (1);
the telescopic mechanism (2) comprises a first telescopic frame (201), a second telescopic frame (202), a third telescopic frame (203), a fourth telescopic frame (204), a first pressure receiving plate (205), a second pressure receiving plate (206), a motor base (207), a first motor (208), a screw rod (209), a nut (210) and a protection plate (211), wherein the bottom of a support plate (3) at one end of the first telescopic frame (201) is hinged, the other end of the first telescopic frame (201) is hinged with the top of the first pressure receiving plate (205), one end of the second telescopic frame (202) is hinged with the bottom of the first pressure receiving plate (205), the other end of the second telescopic frame (202) is hinged with the top of the base (1), the bottom of the support plate (3) at one end of the third telescopic frame (203) is hinged, the other end of the third telescopic frame (203) is hinged with the top of the second pressure receiving plate (206), one end of the fourth telescopic frame (204) is hinged with the bottom of the second pressure receiving plate (206), the other end of the fourth telescopic frame (204) is hinged to the top of the base (1), the motor base (207) is fixedly connected to the right side of the second pressure receiving plate (206), the first motor (208) is fixedly connected to the top of the motor base (207), one end of the screw rod (209) is fixedly connected to the rotating end of the first motor (208), the other end of the screw rod (209) penetrates through the second pressure receiving plate (206) and the first pressure receiving plate (205) and extends to the left side of the first pressure receiving plate (205), the nut (210) is fixedly connected to the left side of the first pressure receiving plate (205), the nut (210) is in threaded connection with the screw rod (209), and the protection plate (211) is fixedly connected to the left side of the screw rod (209);
the random distribution model mechanism (4) comprises a collection box (401), an experiment box (402), a throwing pipeline (403), an experiment plate (404), a left guide plate (405) and a right guide plate (406), wherein the collection box (401) is fixedly connected to the top of the support plate (3), the experiment box (402) is fixedly connected to the middle of the top of the collection box (401), the throwing pipeline (403) is fixedly connected to the top of the experiment box (402), the bottom of the throwing pipeline (403) penetrates through the experiment box (402) and extends to the inside of the experiment box (402), the experiment plate (404) is fixedly connected to the inside of the experiment box (402), the experiment plate (404) is arranged below the throwing pipeline (403) and horizontally arranged, the left guide plate (405) is fixedly connected to the bottom of the inside of the experiment box (402) and arranged at the left lower side of the experiment plate (404), the right guide plate (406) is fixedly connected to the bottom inside the experiment box (402) and arranged at the lower right of the experiment plate (404).
2. A model teaching aid for mathematical probability teaching as claimed in claim 1, wherein: anti-skidding mechanism (6) include second motor (601), bull stick (602), gear (603), rack (604), antiskid ribbed tile (605), second motor (601) fixed connection is in the inside of base (1), bull stick (602) fixed connection is in the rotation end of second motor (601), gear (603) are fixed to be cup jointed on the surface of bull stick (602), rack (604) and gear (603) meshing, and the bottom of rack (604) passes base (1) and extends to the bottom of base (1), antiskid ribbed tile (605) fixed connection bests the bottom of rack (604).
3. A model teaching aid for mathematical probability teaching as claimed in claim 1, wherein: the fixing mechanism (7) comprises a first fixing plate (701), a second fixing plate (702), a positioning block (703), a sliding block (704) and a handle (705), the first fixing plate (701) is fixedly connected to the top of the supporting plate (3), the first fixing plate (701) is arranged on the front side of the collecting box (401), the second fixing plate (702) is fixedly connected to the top of the supporting plate (3), the second fixing plate (702) is arranged on the back side of the collecting box (401), a sliding groove is arranged in the second fixing plate (702), a first positioning groove is arranged on the back side of the collecting box (401), the positioning block (703) is slidably connected in the sliding groove, one end of the positioning block (703) is in sliding contact with the first positioning groove, a second positioning groove is arranged on the surface of the positioning block (703), the sliding block (704) is slidably connected in the sliding groove, and one end of the sliding block (704) is in sliding contact with the second positioning groove, the handle (705) is fixedly connected to the surface of the sliding block (704), and one end of the handle (705) penetrates through the second fixing plate (702) and extends to the back of the second fixing plate (702).
4. A model teaching aid for mathematical probability teaching as claimed in claim 1, wherein: the experiment box (402) is provided with a first opening at the left side and a second opening at the right side.
5. A model teaching aid for mathematical probability teaching as claimed in claim 1, wherein: the number of the universal wheels (5) is four, and the four universal wheels (5) are uniformly arranged at the bottom of the base (1).
6. A model teaching aid for mathematical probability teaching as claimed in claim 2, wherein: the antiskid plate (605) is made of a wood plate, and a plurality of grains are arranged at the bottom of the antiskid plate (605).
7. A model teaching aid for mathematical probability teaching as claimed in claim 2, wherein: the side surface of the rack (604) is in contact with the base (1) box body.
8. A model teaching aid for mathematical probability teaching as claimed in claim 1, wherein: the protection plate (211) is made of a wood plate, and the side face of the protection plate (211) is smoothly arranged.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202022810857.3U CN213365899U (en) | 2020-11-30 | 2020-11-30 | Model teaching aid for mathematical probability teaching |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202022810857.3U CN213365899U (en) | 2020-11-30 | 2020-11-30 | Model teaching aid for mathematical probability teaching |
Publications (1)
Publication Number | Publication Date |
---|---|
CN213365899U true CN213365899U (en) | 2021-06-04 |
Family
ID=76136605
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202022810857.3U Expired - Fee Related CN213365899U (en) | 2020-11-30 | 2020-11-30 | Model teaching aid for mathematical probability teaching |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN213365899U (en) |
-
2020
- 2020-11-30 CN CN202022810857.3U patent/CN213365899U/en not_active Expired - Fee Related
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN210223173U (en) | Special teaching aid of mental health education | |
CN213365899U (en) | Model teaching aid for mathematical probability teaching | |
CN210890812U (en) | Network security teaching system based on microcontroller | |
CN111743298A (en) | Multi-media movable multi-functional podium | |
CN217951762U (en) | Be used for territory space planning data acquisition mapping device | |
CN209860455U (en) | Maintenance frame for power equipment | |
CN111789429A (en) | Multifunctional drawing device for environmental design | |
CN204808614U (en) | Advertisement teaching operation panel | |
CN108994148B (en) | Portable stainless steel hole pressing machine | |
CN112967568B (en) | Marketing teaching contrast learning device | |
CN213545827U (en) | Progress display board for civil engineering construction management | |
CN115013665A (en) | Foundation pile self-balancing method static test displacement observation platform device | |
CN212060139U (en) | Air environment monitoring device | |
CN210355868U (en) | Special children's both hands coordination training utensil | |
CN213521902U (en) | Direct Digital Synthesis (DDS) -technology-based finger-controlled communication interference simulator | |
CN112555636A (en) | Equipment operation platform for online education based on big data | |
CN216221007U (en) | Architectural design display model | |
CN221079438U (en) | Hydraulic and pneumatic training device | |
CN211454850U (en) | Novel improve information technology teaching of structure device | |
CN218819270U (en) | Collecting equipment supporting device | |
CN217953389U (en) | Portable cable length electronic measuring tool | |
CN215294237U (en) | Wisdom medical treatment basic data acquisition device | |
CN218052468U (en) | Adjustable mobile phone assembling workbench | |
CN110811184A (en) | Rotatable physical instrument storing compartment convenient to take | |
CN217215707U (en) | Metal bridge auxiliary mounting equipment |
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: 20210604 |
|
CF01 | Termination of patent right due to non-payment of annual fee |