阅读说明：本技术 微纳卫星制动帆装置 (Micro-nano satellite braking sail device ) 是由 和向前 马帅领 刘丽坤 杨雯森 于 2021-07-05 设计创作，主要内容包括：本发明提供一种卫星制动帆离轨装置,本装置适用于体积小质量轻甚至1U立方体卫星的离轨,能够解决立方星在完成任务后无法在规定时间内脱离轨道从而成为空间碎片的问题,包括底部框架,底部框架的四个方向上分别设有一内部放置有呈折叠状态帆布的帆布储藏盒,所述帆布呈梯形、且其短边与帆布储藏盒或底部框架连接,各帆布的长边分别位于外侧并可被向外展开,还包括安装于底部框架上的伸缩机构,所述伸缩机构包括四个可分别向前伸缩的柔性伸缩板片,所述柔性伸缩板片收缩后可被弯曲卷绕、伸出后可进行自支撑；四个所述柔性伸缩板片分别从相邻两个帆布储藏盒之间的间隙内伸出,还包括用于将所述柔性伸缩板片伸出的伸出储能机构。(The invention provides a satellite braking sail derailing device which is suitable for derailing of a small-size light-weight even 1U cubic satellite and can solve the problem that the cubic satellite cannot be separated from a track within a specified time after completing a task and becomes space debris; the four flexible telescopic plate pieces extend out of gaps between two adjacent canvas storage boxes respectively and further comprise extending energy storage mechanisms used for extending the flexible telescopic plate pieces out.)

1. A braking sail device for a micro/nano satellite comprises a bottom frame; the method is characterized in that: canvas storage boxes in which canvas in a folded state is placed are respectively arranged in the four directions of the bottom frame, the canvas is trapezoidal, the short edges of the canvas are connected with the canvas storage boxes or the bottom frame, the long edges of the canvas are respectively positioned at the outer sides and can be unfolded outwards, and when the four canvas are unfolded, the canvas storage boxes form a rectangle;

the telescopic mechanism comprises four flexible telescopic plates which can be respectively stretched forwards, and the flexible telescopic plates can be bent and wound after being contracted and can be self-supported after being stretched out; the four flexible telescopic plate pieces extend out of gaps between two adjacent canvas storage boxes respectively, connecting pieces are arranged at the end parts of the flexible telescopic plate pieces positioned at the outer end parts respectively, and the connecting pieces are connected with the top angles of two adjacent canvases at two sides;

the telescopic plate is characterized by also comprising an extending energy storage mechanism for extending the flexible telescopic plate.

2. A micro-nano satellite braking sail device as claimed in claim 1, wherein: the extending energy storage mechanism comprises a flexible telescopic plate winding unit and an energy storage unit for extending the flexible telescopic plate, the flexible telescopic plate winding unit comprises a winding wheel, two ends of the winding wheel are respectively provided with a lower flange plate and an upper flange plate, the centers of the outer side walls of the lower flange plate and the upper flange plate are respectively provided with an upper connecting shaft and a lower connecting shaft, the inner end parts of the four flexible telescopic plates are wound on the winding wheel between the lower flange plate and the upper flange plate after being stacked, and the outer end parts of the four flexible telescopic plates respectively extend out from four directions of the winding wheel; the two sides of four flexible telescopic plates extending out from the rolling wheel are respectively provided with a plurality of groups of guide wheel groups at intervals, the guide wheel groups are arranged along the extending direction of the flexible telescopic plates and extend to the opening of the canvas storage box between two adjacent canvas storage boxes, and each group of guide wheel groups comprises two ball bushings which are respectively sleeved on the fixed shaft of the bottom frame.

The energy storage unit comprises a coil spring support fixedly arranged above the flexible telescopic sheet winding unit, the coil wheel is rotatably connected between the coil spring support and the bottom frame through an upper connecting shaft and a lower connecting shaft at two ends respectively, a coil spring is arranged above the top of the coil spring support, the upper connecting shaft penetrates through the coil spring support and is connected with one end of the coil spring, and the coil wheel can be driven to rotate through potential energy stored by the coil spring.

3. A micro-nano satellite braking sail device as claimed in claim 2, wherein: the coil spring support is provided with an annular surrounding plate, the coil spring is positioned in the tail plate, the upper connecting shaft is provided with an inner clamping groove, the inner side end of the coil spring is clamped in the inner clamping groove, the side wall of the tail plate is provided with an outer clamping groove, and the outer end part of the coil spring is clamped in the outer clamping groove.

4. A micro-nano satellite braking sail device as claimed in claim 1, wherein: the flexible expansion plate is a metal sheet, and the section of the flexible expansion plate is arc-shaped or "(" shape ".

5. A micro-nano satellite braking sail device as claimed in claim 2, wherein: the connecting piece is W-shaped, the end part of the flexible telescopic plate is connected with the middle part of the connecting piece, arc-shaped grooves are arranged on two sides of the connecting piece, and the two arc-shaped grooves can be respectively clamped on the two ball bushings positioned at the foremost ends.

6. A micro-nano satellite braking sail device as claimed in claim 1, wherein: the canvas storage box is a box body with a trapezoidal cubic cavity inside, and the opening end of the long edge of the canvas storage box is arranged outwards.

7. A micro-nano satellite braking sail device as claimed in claim 1, wherein: the opening ends of the canvas storage boxes are respectively provided with a baffle plate, the bottom of the baffle plate is rotatably connected with the bottom frame, and the upper part of the baffle plate is connected with the automatic release structure.

8. A micro-nano satellite braking sail device as claimed in claim 7, wherein: the automatic release structure comprises a groove and a boss which are respectively arranged on the outer side walls of two ends of the baffle plate, when the baffle plate is upright and the opening of the canvas storage box is closed, the convex bodies on the end parts of two adjacent baffle plates are positioned in the groove, and the four baffle plates are sequentially clamped into a city-enclosing rectangle through the boss and the groove from head to tail;

the canvas storage box is characterized by further comprising a thermistor fixed at the top of one of the canvas storage boxes, a tension rope is connected to the upper end of one of the baffle plates, the other end of the tension rope is connected with the canvas storage box, the middle of the tension rope is located on the thermistor and is in contact with the thermistor, and the tension rope can be burnt out after the thermistor is electrified and heated.

9. A micro-nano satellite braking sail device as claimed in claim 8, wherein: the bottom of the baffle is rotatably connected to the side part of the bottom frame through a connecting shaft, a torsional spring is arranged on the connecting shaft, and the stress end of the torsional spring is connected with the baffle and prompts the baffle to be unfolded.

10. A micro-nano satellite braking sail device as claimed in claim 1, wherein: the device is characterized by further comprising an upper cover plate, the upper cover plate is fixed on the top of the energy storage mechanism and connected with a connecting column on the coil spring support, and the upper cover plate, the baffle and the bottom frame enclose the device into a square three-dimensional shape.

Technical Field

The invention relates to the technical field of micro-nano satellite braking sails, in particular to a micro-nano satellite braking sail device.

Background

In recent years, with the rapid development and great success of human space technology, a great deal of space debris (also called space debris) is also produced by human space activities. The existence of space debris seriously threatens the safety of the in-orbit spacecraft and restricts the development of the human space technology. How to slow down the growth of space debris has become an urgent problem to be solved at home and abroad. In terms of current technology conditions, the only effective way to reduce the amount of space debris is to re-enter the earth's dense atmosphere for burnout, i.e., off-track technology.

With the development and demand of high and new technologies, micro-nano satellites are increasingly paid attention by relevant organizations and universities at home and abroad due to the advantages that the micro-nano satellites are small in size, low in power consumption and short in development period, can be grouped and networked, and can complete a plurality of complex space tasks at lower cost. With the increase of the emission quantity of the micro-nano satellites, the influence on the space environment is more and more obvious, and if no reliable off-orbit technology exists, the emission of the micro-nano satellites in the future is limited to a certain extent.

Currently, the main derailment modes include a propelling technology, an inflatable ball technology, an electric power tether, a braking sail and the like. However, due to the volume and mass limitations of the cubic satellite, some of the off-orbit techniques applicable to the conventional satellite are difficult to be applied to the cubic satellite. The propulsion technology occupies some extra propellant on the satellite, improves the quality of the satellite, needs continuous thrust vector control in the off-orbit stage, and puts higher requirements on the service life of other subsystems on the satellite, particularly a power supply and a solar panel. The inflatable ball technology needs a certain pressurizing device carried on a satellite, certain potential safety hazards are brought to satellite launching and long-time work, and the service life of the technology is shortened due to inevitable gas leakage caused by high-pressure gas. The electric power tether can reach tens of meters or even kilometers after being unfolded, certain task risk is increased for low orbit satellites, in addition, the electric power tether cuts magnetic lines of a geomagnetic field by utilizing a high-speed moving conductive rope to generate acting force perpendicular to the tether and the direction of a local magnetic field, and the device has certain limitation for some polar orbit satellites.

The braking sail is mainly used for accelerating the off-orbit of the satellite by improving the atmospheric resistance borne by the satellite in the in-orbit flying process, the satellite is not required to be actively controlled in the working process, the braking sail can be unfolded by depending on the mechanical energy stored by the braking sail, and the braking sail is light in system weight, simple in structure, low in cost, and suitable for low-orbit cubic satellites with quick response and short task periods.

Patrick discloses and reports a brake sail device AEOLDOS suitable for low orbit cubic satellites

(advanced space research54(2014) 82-91), the device depends on the elastic potential energy stored in the system to drive the middle rotating shaft to rotate, so as to deploy the braking sail. Because the area of the braking sail designed by the device is small, the four masts can be unfolded through a rotating shaft, and the 4 sail storage chambers are respectively arranged among the four masts. The system has simple structure, small volume and light weight, and is suitable for the off-orbit of the low-orbit cubic satellite. However, as the orbit height of the cubic satellite is increased, the star mass is increased, and the application of the device has certain limitation.

NASA designed brake sail derailing device Nanosail-D (22 ndAnalaAIAA/USU). The device arranges the sail storage chamber at the top of the unfolding mechanism, and the area of the unfolded device can reach 10m2 at most. The device is not suitable for cubic satellites with small volume because the device occupies 2U (20cm by 10cm) of space in the satellite.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, adapt to the practical requirements and provide a satellite braking sail derailing device which is suitable for derailing of a small-size light-weight even 1U cube satellite, can solve the problem that the cube satellite cannot be separated from the orbit within a specified time after completing a task to become space fragments, and also solves the problem that no space is provided for installing a braking sail device in the satellite due to the small volume of the cube satellite.

In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:

designing a micro-nano satellite braking sail device, which comprises a bottom frame; the canvas storage box is internally provided with canvas in a folded state in four directions of the bottom frame, the canvas is trapezoidal, the short edge of the canvas is connected with the canvas storage box or the bottom frame, the long edge of each canvas is positioned at the outer side and can be unfolded outwards, and when the four canvases are unfolded, the four canvases form a rectangle together;

the telescopic mechanism comprises four flexible telescopic plates which can be respectively stretched forwards, and the flexible telescopic plates can be bent and wound after being contracted and can be self-supported after being stretched out; the four flexible telescopic plate pieces extend out of gaps between two adjacent canvas storage boxes respectively, connecting pieces are arranged at the end parts of the flexible telescopic plate pieces positioned at the outer end parts respectively, and the connecting pieces are connected with the top angles of two adjacent canvases at two sides;

the telescopic plate is characterized by also comprising an extending energy storage mechanism for extending the flexible telescopic plate.

The extending energy storage mechanism comprises a flexible telescopic plate winding unit and an energy storage unit for extending the flexible telescopic plate, the flexible telescopic plate winding unit comprises a winding wheel, two ends of the winding wheel are respectively provided with a lower flange plate and an upper flange plate, the centers of the outer side walls of the lower flange plate and the upper flange plate are respectively provided with an upper connecting shaft and a lower connecting shaft, the inner end parts of the four flexible telescopic plates are wound on the winding wheel between the lower flange plate and the upper flange plate after being stacked, and the outer end parts of the four flexible telescopic plates respectively extend out from four directions of the winding wheel; the two sides of four flexible telescopic plates extending out from the rolling wheel are respectively provided with a plurality of groups of guide wheel groups at intervals, the guide wheel groups are arranged along the extending direction of the flexible telescopic plates and extend to the opening of the canvas storage box between two adjacent canvas storage boxes, and each group of guide wheel groups comprises two ball bushings which are respectively sleeved on the fixed shaft of the bottom frame.

The energy storage unit comprises a coil spring support fixedly arranged above the flexible telescopic sheet winding unit, the coil wheel is rotatably connected between the coil spring support and the bottom frame through an upper connecting shaft and a lower connecting shaft at two ends respectively, a coil spring is arranged above the top of the coil spring support, the upper connecting shaft penetrates through the coil spring support and is connected with one end of the coil spring, and the coil wheel can be driven to rotate through potential energy stored by the coil spring.

The coil spring support is provided with an annular surrounding plate, the coil spring is positioned in the tail plate, the upper connecting shaft is provided with an inner clamping groove, the inner side end of the coil spring is clamped in the inner clamping groove, the side wall of the tail plate is provided with an outer clamping groove, and the outer end part of the coil spring is clamped in the outer clamping groove.

The flexible expansion plate is a metal sheet, and the section of the flexible expansion plate is arc-shaped or "(" shape ".

The connecting piece is W-shaped, the end part of the flexible telescopic plate is connected with the middle part of the connecting piece, arc-shaped grooves are arranged on two sides of the connecting piece, and the two arc-shaped grooves can be respectively clamped on the two ball bushings positioned at the foremost ends.

The canvas storage box is a box body with a trapezoidal cubic cavity inside, and the opening end of the long edge of the canvas storage box is arranged outwards.

The opening ends of the canvas storage boxes are respectively provided with a baffle plate, the bottom of the baffle plate is rotatably connected with the bottom frame, and the upper part of the baffle plate is connected with the automatic release structure.

The automatic release structure comprises a groove and a boss which are respectively arranged on the outer side walls of two ends of the baffle plate, when the baffle plate is upright and the opening of the canvas storage box is closed, the convex bodies on the end parts of two adjacent baffle plates are positioned in the groove, and the four baffle plates are sequentially clamped into a city-enclosing rectangle through the boss and the groove from head to tail;

the canvas storage box is characterized by further comprising a thermistor fixed at the top of one of the canvas storage boxes, a tension rope is connected to the upper end of one of the baffle plates, the other end of the tension rope is connected with the canvas storage box, the middle of the tension rope is located on the thermistor and is in contact with the thermistor, and the tension rope can be burnt out after the thermistor is electrified and heated.

The bottom of the baffle is rotatably connected to the side part of the bottom frame through a connecting shaft, a torsional spring is arranged on the connecting shaft, and the stress end of the torsional spring is connected with the baffle and prompts the baffle to be unfolded.

The device is characterized by further comprising an upper cover plate, the upper cover plate is fixed on the top of the energy storage mechanism and connected with a connecting column on the coil spring support, and the upper cover plate, the baffle and the bottom frame enclose the device into a square three-dimensional shape.

The invention has the beneficial effects that:

the design has small volume, only occupies 0.4U of space and light weight, and can be carried in a 1U cube star;

the design cost is low, the manufacture is convenient, standard parts can be selected, and the parts can be conveniently disassembled;

the design can be repeatedly used, and the service life of the polyimide canvas is long;

the unlocking mode of the design is a blowing mode, no impact force is generated, and a complex mechanical mechanism is not needed.

Drawings

FIG. 1 is a schematic view of the main structure of the device in a storage state;

FIG. 2 is a schematic view of the structure of FIG. 1 from another perspective;

FIG. 3 is a schematic structural view of the apparatus after the upper cover plate and one of the baffles are taken out;

FIG. 4 is a schematic view of the canvas storage case and the side panels of the present apparatus;

FIG. 5 is a schematic view of the structure of FIG. 3 with the baffle removed;

FIG. 6 is a schematic view of the structure of the bottom frame, its upper ball bushing and the open state of the baffle plate in the present apparatus;

FIG. 7 is a schematic view of each main structure of the present apparatus in an exploded state;

FIG. 8 is a schematic view of the main structure of the canvas and the energy storage unit in the device;

FIG. 9 is a schematic view of the main structure of the bottom frame and the extension mechanism and the extension energy storage mechanism thereon;

FIG. 10 is a schematic view of the main structure of the flexible expansion sheet winding unit in the device;

FIG. 11 is a schematic diagram of the main structure of the energy storage unit in the present device;

FIG. 12 is a schematic view of the reel structure of the present apparatus;

FIG. 13 is a schematic view of the flexible retractable sheet 22 of the present device in engagement with the reel;

fig. 14 is a schematic structural view of the device in a deployed state.

Detailed Description

The invention is further illustrated with reference to the following figures and examples:

example 1: a braking sail device for a micro-nano satellite, which is shown in figures 1 to 14.

It includes bottom frame 1, upper cover plate 6, its in this design be equipped with a inside canvas storage box 3 that is fold condition canvas of placing respectively on four directions of bottom frame 1, as shown in fig. 14, canvas 31 is trapezoidal, and the cavity internal connection in its minor face and the canvas storage box 3, and the long limit of each canvas 31 is located the outside respectively, and the canvas after folding is trapezoidal (shown in fig. 8), and the long limit of canvas 31 is located the outside and can be expanded after outwards stretching, constitutes the rectangle jointly after four canvas 31 are expanded.

The canvas storage box further comprises a telescopic mechanism arranged on the bottom frame 1, the telescopic mechanism comprises four flexible telescopic plates 22 capable of respectively extending forwards, the flexible telescopic plates 22 are metal sheets, the cross sections of the flexible telescopic plates are arc-shaped or '(' shaped), the flexible telescopic plates can be bent and wound after being contracted and can be self-supported after being extended, as shown in figure 9, the four flexible telescopic plates 22 respectively extend out from the gap between two adjacent canvas storage boxes 3, and connecting pieces 23 are respectively arranged at the end parts of the flexible telescopic plates 22 positioned at the outer end parts.

In this embodiment, the connecting member 23 is W-shaped, the end portion of the flexible expansion plate 22 is connected to the middle portion of the connecting member, two sides of the connecting member are provided with arc-shaped grooves 231, the two arc-shaped grooves 231 can be respectively clamped on two ball bushes 15 (mentioned later) located at the foremost end, and the connecting member 23 is connected to the top corners of two canvases 31 at two adjacent sides through a connecting ring 232.

The telescopic energy storage device is characterized by further comprising an extending energy storage mechanism for extending the flexible telescopic plate, wherein the extending energy storage mechanism comprises a flexible telescopic plate winding unit 2 and an energy storage unit 5 for extending the flexible telescopic plate; referring to fig. 9-13, the flexible expansion sheet winding unit 2 includes a winding wheel 24 having a lower flange 21 and an upper flange 25 at two ends thereof, the centers of the outer sidewalls of the lower flange 21 and the upper flange 24 are respectively provided with an upper connecting shaft 27 and a lower connecting shaft 28, the inner ends of four flexible expansion sheets 22 are laminated and wound around the winding wheel 24 between the lower flange and the upper flange, and the outer ends of the four flexible expansion sheets extend out from the winding wheel 24 in four directions; in practical use, the end portions of the four flexible expansion plates can be realized by two flexible expansion plates, as shown in fig. 13, the rolling wheel of the flexible expansion plate is formed by four parallel cylinders which are distributed in a square shape, the two flexible expansion plates respectively penetrate through two symmetrically distributed gaps formed by the four cylinders, the middle portions of the two flexible expansion plates are enabled to be positioned in the four cylinders, the four end portions formed by the two flexible expansion plates can form the four flexible expansion plates which extend forwards, the four flexible expansion plates are stacked and then wound on the rolling wheel in the same direction, and the outer end portions are enabled to extend forwards into the guide wheel set and are connected with the connecting piece 23.

Specifically, the two sides of the four flexible retractable plates 22 extending from the winding wheel 24 are respectively provided with a plurality of groups of guide wheel sets at intervals, the guide wheel sets are arranged along the extending direction of the flexible retractable plates 22 and extend to the opening of the canvas storage box between two adjacent canvas storage boxes, and each group of guide wheel sets comprises two ball bushings 15 which are respectively sleeved on the fixed shaft of the bottom frame.

Specifically, the energy storage unit 5 comprises a coil spring support 51 fixedly mounted above the flexible expansion sheet winding unit 2, the winding wheel 24 is rotatably connected between the coil spring support 51 and the bottom frame 1 through an upper connecting shaft 27 and a lower connecting shaft 28 at two ends respectively, a coil spring 52 is arranged above the top of the coil spring support 51, the upper connecting shaft 27 penetrates through the coil spring support 51 and is connected with an inner end 53 of the coil spring, and the potential energy stored by the coil spring 52 can drive the winding wheel 24 to rotate; further, an annular surrounding plate 512 is arranged on the coil spring support 51, the coil spring 52 is located in the tail plate, an inner clamping groove is formed in the upper connecting shaft 27, the inner side end 53 of the coil spring is clamped in the inner clamping groove, an outer clamping groove 55 is formed in the side wall of the tail plate, and the outer end 54 of the coil spring is clamped in the outer clamping groove.

As shown in fig. 2-7, the canvas storage box 3 is a box body with a trapezoidal cubic cavity inside, and the open ends of the long sides of the canvas storage box 3 are arranged outwards, the open end of each canvas storage box 3 is provided with a baffle plate 14, the bottom of the baffle plate 14 is rotatably connected with the bottom frame 1, the upper part of the baffle plate is connected with the automatic release structure, so to speak, the bottom of the baffle plate 14 is rotatably connected with the side part of the bottom frame through a connecting shaft 13, a torsion spring 12 is arranged on the connecting shaft, and the stressed end of the torsion spring 12 is connected with the baffle plate 14 and urges the baffle plate to be unfolded.

The automatic release structure comprises a groove 141 and a boss 142 which are respectively arranged on the outer side walls of two ends of the baffle plate, when the baffle plate 14 is upright and the opening of the canvas storage box 3 is closed, the convex bodies 142 on the end parts of two adjacent baffle plates are positioned in the groove 141, and the four baffle plates are sequentially clamped into a city-enclosing rectangle through the boss and the groove end to end; the canvas storage box is characterized by further comprising a thermistor 41 fixed on the top 31 of one of the canvas storage boxes, wherein a tension rope 42 is connected to the upper end of one of the baffle plates 14, the other end of the tension rope 42 is connected with the canvas storage box 3, the middle part of the tension rope is located on the thermistor and is in contact with the thermistor, and the tension rope can be burnt out after the thermistor is electrified and heated.

The upper cover plate 6 is fixed on the top of the energy storage mechanism and connected with a connecting column on the coil spring support, and the upper cover plate, the baffle and the bottom frame enclose the device into a square three-dimensional shape.

The state of the canvas in the undeployed state is as shown in fig. 1 and 2, at this time, four baffles 14 connected on the bottom plate 11 of the bottom frame are matched with the groove 142 sequentially from head to tail through the lug boss 141, so that the purpose that only one baffle needs to be restrained and released, and four baffles can be operated simultaneously can be realized; at this time, the flap 14 is mounted on the base plate 11 through the root torsion spring 12 and the connecting shaft 13, and the energy stored in the root torsion spring 12 may rotate the flap 14 to be opened along the connecting shaft on the base plate 11 when the flap is unfolded.

At this time, thirty-two ball bushings 15 are installed on the upper surface of the bottom plate 11, a plurality of freely rotating rotary balls can be installed on the peripheral side walls of the ball bushings 15, and the plurality of ball bushings 15 can be combined to play a role in guiding and reducing friction on the flexible expansion plate 22.

As shown in fig. 9 and 11, the lower flange 21, the upper flange 25 and the winding wheel 24 are connected by screws to form a support structure, two rolling bearings 26 are respectively mounted on the upper flange and the lower flange to make the whole structure rotate axially, the end of the shaft of the lower flange 21 is provided with a notch and extends out of the bottom frame, so that the winding wheel and the top coil spring can be rotated by an external tool, and the clamping groove at the end of the shaft of the upper flange 25 is used for clamping one end of the coil spring 52, so that the winding wheel can be driven to rotate when the coil spring is released. The wind spring is in a stressed potential energy storage state when the canvas is in an undeployed state, at this time, the front end of the flexible telescopic plate 22 is as shown in fig. 8 and 9, at this time, the two arc-shaped grooves 231 are respectively clamped on the two ball bushes 15 (mentioned later) positioned at the foremost end and the two corners of the canvas end are tensioned through the connecting pieces 23, at this time, the baffle is in a closed state, at this time, the front end of the flexible telescopic plate 22 is limited by the connecting pieces 23 and cannot extend forwards (the baffle limits the connecting pieces 23 to extend forwards and simultaneously limits the canvas to be pulled outwards), and at this time, the wind spring is in a potential energy unreleased state.

In this embodiment, the canvas is made of a 0.02mm mylar film, and has two ends respectively provided with a circular hole, one end of the connection ring 33 is connected to the circular hole of the canvas 31, and the other end is connected to the circular hole of the connection member, so that when the flexible retractable plate 22 is released and popped up, the canvas is pulled out and unfolded together to form the plane 32.

In this state the pull cord is pulled taut and pressed against the thermistor 41 on the circuit board. When the canvas needs to be unfolded, the circuit board is electrified, then the thermistor generates heat to blow the pull rope 42, the restraint on the baffle plates 14 is removed after the pull rope 42 is blown, the baffle plates 14 are unfolded outwards along the root part under the action of the root part torsion spring 12, afterwards, as the four baffle plates 14 are matched with the lug bosses 141 and the grooves 142 in sequence from head to tail, the rest 3 baffle plates can be released in sequence only by opening one baffle plate, when the baffle plates are opened, the limiting effect on the connecting piece 23 and the canvas is removed, the potential energy of the coil spring is released at the moment, the coil spring drives the coil wheel to rotate and the four flexible telescopic plate pieces 22 stretching out, at the moment, the energy of the coil spring 52 is released, the shaft of the upper flange plate 25 is driven to rotate, the flexible telescopic plate pieces 22 are driven to rotate, the flexible telescopic plate pieces 22 can stretch out under the guiding effect of the ball bush 15, and the canvas 32 is taken out by the connecting piece 23 at the tail end of the flexible telescopic plate pieces 22 in the stretching process, finally, the area formed by unfolding the 4 pieces of canvas is 2 square meters.

When the canvas to be braked is to be restored to the furled state, the canvas 32 is folded into a trapezoid to be stored in the canvas storage box 331, then the opening at the tail end of the shaft of the lower flange plate 21 is rotated in the screwing direction of the external tool and the coil spring 52, so that the flexible expansion plate 22 is contracted, the coil spring 52 is screwed to store elastic potential energy, then the four baffle plates 14 are closed in sequence, the baffle plate connecting pieces 23 are restrained, the flexible expansion plate 22 is prevented from being popped up under the action of the coil spring 52, and finally the pull rope 42 is used for tightening one baffle plate, so that the furled state of the canvas to be braked is restored.

The embodiments of the present invention are disclosed as the preferred embodiments, but not limited thereto, and those skilled in the art can easily understand the spirit of the present invention and make various extensions and changes without departing from the spirit of the present invention.