A protective cover opening and closing device

Abstract

The present application belongs to the field of sash, door leaf or similar components for closing openings, and particularly relates to a protective cover opening and closing device. In order to simplify the structure and reduce the cost, the protective cover opening and closing device of the present application comprises a rack and a protective cover, the rack is provided with a locking block, the inside of the protective cover is hinged with a lock tongue and a fifth connecting rod, the lock tongue and the fifth connecting rod are hinged with a sixth connecting rod and form a four-connecting-rod mechanism; the protective cover is further hinged with a second connecting rod, the rack is provided with a direct-acting driving mechanism for controlling the forward and reverse rotation of one end of the second connecting rod, when the second connecting rod rotates forward, the fifth connecting rod is driven to rotate forward through a transmission connecting rod to make the lock tongue move to a locking state, when the second connecting rod rotates reversely, the lock tongue is away from the locking block, the protective cover is further provided with a stop portion for cooperating with the second connecting rod when the second connecting rod reversely rotates to a limit position, so as to push the protective cover to open upward under the continuous driving of the direct-acting driving mechanism. The protective cover is locked, unlocked and opened and closed through a set of direct-acting driving mechanism, the structure is simple and the cost is low.

Description

Technical Field

[0001] This invention belongs to the field of window sashes, door sashes or similar components for closing openings, and particularly relates to a protective cover opening and closing device. Background Technology

[0002] In existing technologies, it is often necessary to have windows on the equipment and to install protective covers at the windows. When it is necessary to perform related operations through the window, the protective cover needs to be opened to carry out the operation; after the operation is completed, the protective cover needs to be closed to prevent dust or rainwater and other debris from entering the equipment.

[0003] For example, Chinese utility model patent CN216486858U, with an authorization announcement date of May 10, 2022, discloses a comprehensive training device based on the Internet of Things (IoT). This device includes a training table, a protective cover hinged at one end to the training table, and a hydraulic cylinder for opening the protective cover. When IoT training is required, the piston rod of the hydraulic cylinder moves upward, opening the protective cover. When the protective cover is opened to a suitable position, the piston rod of the hydraulic cylinder stops moving, thus stopping the protective cover, allowing the operator to operate the training equipment. After the operation is completed, the piston rod of the hydraulic cylinder moves downward, closing the protective cover.

[0004] When the protective cover is large, the end of the cover away from its own axis of rotation is prone to tilting upwards when it is subjected to external vibrations and disturbances, which can cause dust or rainwater to enter the cover and affect its sealing performance.

[0005] To improve the sealing performance of the protective cover, a locking structure that locks to the equipment frame can be installed at the end of the cover away from its own axis of rotation. Referring to Chinese Utility Model Patent No. CN209523232U, authorized on October 22, 2019, the locking structure may include a motor installed at the bottom of the protective cover, a pin connected to the motor output and capable of translational movement, and a socket located on the frame. After the protective cover is closed, the motor drives the pin to insert into the socket, thereby preventing the end of the protective cover away from its own axis of rotation from tilting upwards and improving the sealing performance of the protective cover.

[0006] However, in the technical solution combining the two patents mentioned above, each time the protective cover is opened, it is necessary to first control the motor to drive the pin to exit the insertion hole, and then control the piston rod of the hydraulic cylinder to move upward. That is, the operator needs to issue two operation commands in succession (the command for the pin to exit the insertion hole and the command for the piston rod to rise). Similarly, when closing the protective cover, the operator also needs to issue two operation commands in succession (the command for the piston rod to descend and the command for the pin to insert into the insertion hole), which makes the operation very inconvenient and requires two sets of power mechanisms, resulting in high costs. Summary of the Invention

[0007] The purpose of this invention is to provide a protective cover opening and closing device to solve the technical problem that the operator needs to issue two operation commands each time the protective cover is opened or closed, which is inconvenient and requires two sets of power mechanisms, resulting in high costs.

[0008] To achieve the above objectives, the technical solution of the protective cover opening and closing device provided by the present invention is as follows:

[0009] A protective cover opening and closing device includes a frame and a protective cover hinged to the frame at one end. A locking block is provided on the side of the frame away from the hinged position of the protective cover. A locking tongue and a fifth link are hinged to the inner side of the protective cover. A sixth link is hinged between the locking tongue and the fifth link to form a four-bar linkage. The locking tongue has a locking state in which it engages with the locking block in the opening direction of the protective cover when the fifth and sixth links rotate to a certain angle, so that the protective cover remains closed. A second link is also hinged on the protective cover. A direct drive mechanism is provided on the frame for controlling the forward and reverse rotation of one end of the second link. The other end of the second link is hinged to the fifth link through a transmission link. When the second link rotates forward, it drives the fifth link to rotate forward through the transmission link so that the locking tongue moves to the locking state. When the second link rotates in reverse, the locking tongue moves away from the locking block. The protective cover also has a stop part for engaging with the second link when it rotates to its limit position, so that the protective cover is pushed upward to open under the continued drive of the direct drive mechanism.

[0010] Furthermore, when the latch is in the locked state, the fifth and sixth links are in a collinear dead-point state.

[0011] Furthermore, the locking block includes a first locking plane for locking with the lock tongue, and the lock tongue is provided with a second locking plane corresponding to the first locking plane. When the lock tongue is in the locked state, the first locking plane and the second locking plane stop face to face.

[0012] Furthermore, each locking plane is an inclined plane, and the end of the first locking plane closer to the bolt is higher than the end farther from the bolt.

[0013] Furthermore, the direct drive mechanism is fixedly mounted on the frame. The output end of the direct drive mechanism moves in the up-down direction, and a first link is hinged between the output end and one end of the second link to drive the second link to rotate in the forward and reverse directions when the output end moves up and down.

[0014] Furthermore, the direct drive mechanism consists of an electric cylinder and a second motor that drives the electric cylinder, and the second motor is equipped with a rotary encoder for recording the rotation angle of the second motor.

[0015] Furthermore, the direct drive mechanism includes a vertically extending lead screw, a first motor that drives the lead screw to rotate, a vertically extending guide rod, and a lifting member. The lifting member is provided with a threaded hole that mates with the lead screw and a guide hole that mates with the guide rod, so as to move up and down horizontally when the lead screw rotates. The lifting member constitutes the output end. The first motor is provided with a rotary encoder for recording the rotation angle of the first motor.

[0016] Furthermore, a stop is provided near the end where the second link and the third link are hinged, so as to cooperate with the stop at the end where the second link and the third link are hinged.

[0017] Furthermore, the second link is hinged to the end of the protective cover away from the axis of rotation of the protective cover.

[0018] Furthermore, the transmission linkage includes a third link and a fourth link that are hinged together.

[0019] The beneficial effects of the protective cover opening and closing device of the present invention are as follows: This invention is an improved invention. In this invention, the protective cover is unlocked and driven to rise sequentially using a direct drive mechanism and a linkage mechanism. During this process, only an "open" command needs to be issued to the direct drive mechanism, making operation convenient. Correspondingly, when you want to drive the protective cover to fall or lock it, only a "close" command needs to be issued to the direct drive mechanism, making operation convenient and requiring only one power mechanism, resulting in lower costs.

[0020] The protective cover opening and closing device of the present invention will be described using the example of the protective cover being unlocked and raised during use:

[0021] In the initial state, the protective cover is locked;

[0022] Then, the "open" command is sent to the direct drive mechanism, the output end of the direct drive mechanism begins to move, the second link reverses, and the locking tongue swings away from the locking block;

[0023] After the output end moves to the point where the latch and locking block are unlocked, the second link engages with the stop part. Since the second link is hinged to the protective cover, the relative position of the second link and the protective cover does not change as the output end continues to move. During the continued movement of the output end, the output end drives the second link to rise, and the second link pushes the protective cover to open upward.

[0024] After the protective cover is opened to the set extent, the output end stops moving, thereby stopping the movement of the protective cover. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the protective cover when it is locked in a specific embodiment 1 of the protective cover opening and closing device of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the protective cover when it is unlocked in a specific embodiment 1 of the protective cover opening and closing device of the present invention;

[0027] Figure 3 for Figure 1 Enlarged view of the structure at point A in the middle;

[0028] Figure 4 for Figure 2 Enlarged view of the structure at point B;

[0029] Figure 5 This is a schematic diagram of the structure of the protective cover when it is opened in a specific embodiment 1 of the protective cover opening and closing device of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the protective cover when it is locked in a specific embodiment 2 of the protective cover opening and closing device of the present invention;

[0031] Figure 7 This is a schematic diagram of the structure of the protective cover when it is unlocked in a specific embodiment 2 of the protective cover opening and closing device of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the protective cover when it is opened in a specific embodiment 2 of the protective cover opening and closing device of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Frame; 1-1. First support; 1-2. Second support; 1-3. Third support; 2. Protective cover; 3. Locking tongue; 3-1. Second locking plane; 4. Locking block; 4-1. First locking plane; 5-1. First connecting rod; 5-2. Second connecting rod; 5-3. Third connecting rod; 5-4. Fourth connecting rod; 5-5. Fifth connecting rod; 5-6. Sixth connecting rod; 6. Stop; 7. Guide rod mounting seat; 8. Lead screw mounting seat; 9. Lead screw; 10. Guide rod; 11. Lifting component; 12. First motor; 13. Second motor; 14. Electric cylinder. Detailed Implementation

[0035] To address the problems in the background art, the core inventive concept of this invention is as follows: During the upward movement of the output end, a linkage mechanism converts the translational motion of the output end into the oscillation of the locking tongue. After the protective cover is unlocked, the second link in the linkage mechanism engages with the protective cover stop. Since the second link is hinged to the protective cover, the relative position of the second link and the protective cover does not change as the output end continues to rise, thereby driving the protective cover upward through the first and second links. The protective cover can be unlocked and opened with just one command, making operation simple.

[0036] When the output end is at its lowest point, the fifth and sixth links are on the same straight line. At this time, the four-bar linkage where the locking tongue is located is in a dead point state, thus ensuring that the protective cover is locked.

[0037] The present invention will be further described in detail below with reference to the embodiments.

[0038] Specific embodiment 1 of the protective cover opening and closing device provided by the present invention:

[0039] like Figure 1-5 As shown, the protective cover opening and closing device includes a frame 1 and a protective cover 2 hinged to the frame 1 at one end. The frame 1 is provided with a locking block 4 and a direct drive mechanism that can move the output end in the vertical direction and stop at a set position. The protective cover opening and closing device also includes a locking tongue 3 for locking the protective cover 2 by engaging with the locking block 4 when the output end is at its lowest position. The locking tongue 3 is hinged to the inside of the protective cover 2. A linkage mechanism is connected to the output end for converting the translation of the output end into the rotation of the locking tongue 3.

[0040] The linkage mechanism includes a first link 5-1, a second link 5-2, a third link 5-3, a fourth link 5-4, a fifth link 5-5, and a sixth link 5-6. The middle part of the second link 5-2 is hinged to the protective cover 2, and the fifth link 5-5 is hinged to the inside of the protective cover 2. The fifth link 5-5, the sixth link 5-6, the protective cover 2, and the locking tongue 3 constitute a four-bar linkage mechanism. When the output end is at its lowest point, the fifth link 5-5 and the sixth link 5-6 are on the same straight line.

[0041] One end of the first link 5-1 is hinged to the output end, and the other end is hinged to one end of the second link 5-2. The other end of the second link 5-2 is hinged to one end of the third link 5-3. The other end of the third link 5-3 is hinged to one end of the fourth link 5-4. The other end of the fourth link 5-4 is hinged to the middle of the fifth link 5-5, so that when the output end rises, it drives the locking tongue 3 in the four-bar linkage to swing away from the locking block 4. Among them, the third link 5-3 and the fourth link 5-4, which are hinged together, constitute the transmission link. The output end and the first link 5-1 drive the second link 5-2 to rotate forward and backward. When the second link 5-2 rotates forward, it drives the fifth link 5-5 to rotate forward through the transmission link so that the locking tongue 3 moves to the locking state. When the second link 5-2 rotates backward, the locking tongue 3 moves away from the locking block 4.

[0042] Specifically, the frame includes a first support 1-1, a second support 1-2 and a third support 1-3, a second connecting rod 5-2 is hinged to the first support 1-1, a fifth connecting rod 5-5 is hinged to the second support 1-2, and a locking tongue 3 is hinged to the third support 1-3.

[0043] The protective cover 2 is also provided with a stop part 6 for cooperating with the second link 5-2 after the locking tongue 3 and the locking block 4 are unlocked, so that the second link 5-2 pushes the protective cover 2 to open upward (that is, the protective cover 2 is also provided with a stop part 6 for cooperating with the second link 5-2 when it is reversed to the extreme position). The stop part 6 is set near the end where the second link 5-2 and the third link 5-3 are hinged, so as to cooperate with the end where the second link 5-2 and the third link 5-3 are hinged. The structure is simple.

[0044] In this embodiment, the protective cover 2 is unlocked and driven to rise sequentially using a direct drive mechanism and a linkage mechanism. During this process, only the command "output end rise" needs to be issued to the direct drive mechanism, making the operation convenient. Correspondingly, when it is desired to drive the protective cover 2 to fall or lock the protective cover 2, only the command "output end fall" needs to be issued to the direct drive mechanism, making the operation convenient as well.

[0045] The protective cover opening and closing device of this embodiment will be described using the example of the protective cover 2 being unlocked and raised during use:

[0046] In the initial state, the output terminal is at its lowest position, and the protective cover 2 is locked;

[0047] Then, the command "output end rise" is sent to the direct drive mechanism. The output end of the direct drive mechanism begins to rise. The movement of the output end is transmitted to the locking tongue 3 through the linkage mechanism. At the same time as the output end rises, the locking tongue 3 swings away from the locking block 4 (that is, when the second linkage 5-2 reverses, the locking tongue 3 moves away from the locking block 4).

[0048] After the output end rises to the point where the locking tongue 3 and locking block 4 are unlocked, the second link 5-2 engages with the stop part 6. Since the middle part of the second link 5-2 is hinged to the protective cover 2, the relative position of the second link 5-2 and the protective cover 2 does not change as the output end continues to rise. During the process of the output end continuing to rise, the output end drives the first link 5-1 to rise, the first link 5-1 drives the second link 5-2 to rise, and the second link 5-2 pushes the protective cover 2 to open upward.

[0049] After the protective cover 2 is opened to the set extent, the output end stops moving, thereby stopping the movement of the protective cover 2.

[0050] Correspondingly, as the output end descends, the protective cover 2 continues to descend under the action of gravity. After the protective cover 2 descends to the lowest position, the second link 5-2 rotates forward and separates from the stop part 6, thereby driving the locking tongue 3 in the four-bar linkage to swing toward the locking block 4 through the third link 5-3 and the fourth link 5-4 (that is, when the second link 5-2 rotates forward, the locking tongue 3 approaches the locking block 4).

[0051] When the output end is at its lowest point, the fifth link 5-5 and the sixth link 5-6 are on the same straight line. At this time, the four-bar linkage where the locking tongue 3 is located is in a dead point state, and the locking tongue 3 moves to the locked state, thereby ensuring that the protective cover 2 is firmly locked.

[0052] However, in other specific embodiments, when the locking tongue 3 moves to the locked state, the fifth link 5-5 and the sixth link 5-6 may not be collinear. At this time, the locking tongue 3 and the locking block 4 can also lock the protective cover 2. Although the locking effect is poor, it can still meet the usage requirements in non-harsh environments.

[0053] In one specific embodiment, the locking block 4 includes a first locking plane 4-1 for locking and engaging with the locking tongue 3. The locking tongue 3 is provided with a second locking plane 3-1 corresponding to the first locking plane 4-1. When the output end is at its lowest point, the first locking plane 4-1 and the second locking plane 3-1 stop each other. The structure is simple and the locking effect is good.

[0054] However, in other specific embodiments, one of the locking block 4 and the locking tongue 3 may have an outwardly protruding locking arc surface, and the other may have an inwardly recessed locking arc groove. When the output end is at its lowest point, the locking arc surface enters the locking arc groove and cooperates with the bottom wall of the locking arc groove to stop, thereby locking the protective cover 2.

[0055] To simplify the structure, in one specific implementation, each locking plane is an inclined plane, and the end of the first locking plane 4-1 near the latch 3 is higher than the end away from the latch 3, resulting in a simple structure.

[0056] However, in other specific embodiments, the locking plane can be located in the horizontal plane, or the end of the first locking plane 4-1 near the latch 3 can be lower than the end away from the latch 3. The latch 3 includes the latch 3 body and an elastic pad fixed on the latch 3 body. One surface of the elastic pad forms the second locking plane 3-1. When the latch 3 swings away from the locking block 4, the elastic pad can adaptably deform to increase the contact area between the first locking plane 4-1 and the second locking plane 3-1 while preventing the latch 3 from being unable to swing away from the locking block 4.

[0057] To simplify the structure, the direct-drive mechanism includes a vertically extending lead screw 9, a first motor 12 that drives the lead screw 9 to rotate, a vertically extending guide rod 10, and a lifting component 11. The lead screw 9 and the guide rod 10 are respectively mounted on the frame 1 via a lead screw mounting seat 8 and a guide rod mounting seat 7. The lifting component 11 is provided with a threaded hole that mates with the lead screw 9 and a guide hole that mates with the guide rod 10, so that it can move up and down horizontally when the lead screw 9 rotates. The lifting component 11 constitutes the output end. The lifting component 11 can be a lifting plate, a lifting block, or a lifting rod, etc., and the structure is simple.

[0058] To facilitate control over the opening degree of the protective cover 2, as a specific implementation, a rotary encoder is installed on the first motor 12 to record the rotation angle of the first motor 12. The rotary encoder can also record the number of rotations of the motor, thereby deriving the number of rotations of the lead screw 9. Based on the number of rotations of the lead screw 9, the distance traveled by the lifting component 11 can be derived, and thus the opening degree of the protective cover 2 can be determined. By controlling the number of rotations of the first motor 12 based on the data from the rotary encoder, the opening degree of the protective cover 2 can be precisely controlled.

[0059] However, in environments where there are no precise requirements for the opening degree of the protective cover 2, a rotary encoder may not be necessary.

[0060] To simplify the structure, in one specific implementation, the second link 5-2 is hinged to the end of the protective cover 2 away from the axis of rotation of the protective cover 2, so that the second link 5-2 can push the protective cover 2 upward with a small force, thereby enabling the output end to push the first link 5-1, the second link 5-2 and the protective cover 2 upward with a small force, resulting in a simple structure.

[0061] However, in other specific embodiments, the second connecting rod 5-2 can also be hinged to the middle of the protective cover 2 or to the side of the protective cover 2 near its own rotation axis. In this case, it is necessary to increase the output power of the first motor 12, or to set a reducer between the first motor 12 and the lead screw 9 to increase the force applied to the first connecting rod 5-1 by the output end, thereby increasing the force of the second connecting rod 5-2 pushing the protective cover 2.

[0062] The rotation axis of the protective cover 2 is defined to extend in the front-to-back direction. Compared with the technical solution of setting only one set of direct drive mechanism, linkage mechanism, locking tongue 3 and locking block 4 at the front or rear end of the protective cover 2, as a specific implementation, the number of the direct drive mechanism, linkage mechanism, locking tongue 3 and locking block 4 is two sets, and they are respectively set at the front and rear ends of the protective cover 2. This reduces the output power requirement of a single first motor 12. At the same time, locking the protective cover 2 on both the front and rear sides can better prevent the corners of the protective cover 2 from curling up and improve the sealing performance of the protective cover 2.

[0063] Specific embodiment 2 of the protective cover opening and closing device provided by the present invention:

[0064] The purpose of this embodiment is to provide a protective cover opening and closing device with a different direct-drive mechanism.

[0065] In reference Figure 1-5 On the basis of, such as Figure 6-8As shown, the main difference between this embodiment and specific embodiment 1 is that in specific embodiment 1, the direct drive mechanism includes a first motor 12, a lead screw 9, a guide rod 10 and a lifting member 11, while in this embodiment, the direct drive mechanism is an electric cylinder 14 and a second motor 13 that drives the electric cylinder 14. The output end of the electric cylinder 14 constitutes the output end of the direct drive mechanism, which has a simple structure.

[0066] When precise control of the opening degree of the protective cover 2 is required, the second motor 13 is also equipped with a rotary encoder for recording the rotation angle of the second motor 13.

[0067] In other embodiments, when the accuracy requirement for the opening degree of the protective cover 2 is not high, a rotary encoder may not be required. In other embodiments, the output end of a direct-drive mechanism such as a hydraulic cylinder, electric push rod, or pneumatic cylinder may be hinged to the first connecting rod 5-1.

[0068] Specific embodiment 3 of the protective cover opening and closing device provided by the present invention:

[0069] The purpose of this embodiment is to provide a protective cover opening and closing device with a different linkage mechanism.

[0070] Reference Figure 1-8 As shown, the main difference between this embodiment and specific embodiment 1 is that in specific embodiment 1, the linkage mechanism includes a first link 5-1, and the third link 5-3 and the fourth link 5-4 constitute a transmission link. However, in this embodiment, the linkage mechanism does not include the first link 5-1, and the transmission link is only one link.

[0071] In this embodiment, a first guide hole is provided on the output end, and the second connecting rod 5-2 is hinged in the first guide hole to convert the translation of the output end into the rotation of the second connecting rod; the fifth connecting rod 5-5 is provided with a second guide hole, and the transmission connecting rod is hinged in the second guide hole to drive the four-bar linkage with one connecting rod. In the art, using guide holes to transmit the motion between connecting rods is a mature prior art, and will not be elaborated further here.

[0072] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A protective cover opening and closing device comprising a frame and a protective cover hingedly attached at one end to the frame, characterized in that, The locking block is arranged on the rack away from the hinged position of the protective cover, the locking tongue and the fifth connecting rod are hinged in the protective cover, the sixth connecting rod is hinged between the locking tongue and the fifth connecting rod and forms a four-connecting-rod mechanism, the locking tongue has a locking state of being blocked with the locking block in the opening direction of the protective cover when the fifth and sixth connecting rods are rotated to the dead point state of being collinear, so as to keep the protective cover closed; the second connecting rod is also hinged on the protective cover, the direct drive mechanism is arranged on the rack for controlling the forward and reverse rotation of one end of the second connecting rod, the other end of the second connecting rod is hinged with the fifth connecting rod through the transmission connecting rod, the fifth connecting rod is driven to rotate forward by the transmission connecting rod when the second connecting rod rotates forward, so as to drive the locking tongue to move to the locking state, the locking tongue is away from the locking block when the second connecting rod rotates reversely, and the stop portion is arranged on the protective cover for being blocked with the second connecting rod when the second connecting rod rotates reversely to the limit position, so as to push the protective cover to open upward under the continuous driving of the direct drive mechanism.

2. The shield cover opening and closing device according to claim 1, wherein The locking block comprises a first locking plane for locking with the locking tongue, the locking tongue is provided with a second locking plane corresponding to the first locking plane, and the first locking plane and the second locking plane are face-to-face blocked when the locking tongue is in the locking state.

3. The shield cover opening and closing device according to claim 2, wherein Each locking plane is an inclined plane, and the first locking plane is higher at the end close to the locking tongue than at the end away from the locking tongue.

4. A closure device according to any one of claims 1 to 3, wherein the closure device is a protective cap. The direct drive mechanism is fixedly arranged on the rack, the output end of the direct drive mechanism moves in the up-down direction, and the first connecting rod is hinged between the output end and one end of the second connecting rod, so as to drive the second connecting rod to rotate reversely and forwardly when the output end moves up and down.

5. The shield cover opening and closing device according to claim 4, wherein The direct drive mechanism is an electric cylinder and a second motor for driving the electric cylinder to work, and the second motor is provided with a rotary encoder for recording the rotation angle of the second motor.

6. The shield cover opening and closing device according to claim 4, wherein The direct drive mechanism comprises a vertically extending lead screw, a first motor for driving the lead screw to rotate, a vertically extending guide rod and a lifting piece, the lifting piece is provided with a threaded hole matched with the lead screw and a guide hole matched with the guide rod for moving up and down when the lead screw rotates, and the lifting piece constitutes the output end, and the first motor is provided with a rotary encoder for recording the rotation angle of the first motor.

7. A closure device according to any one of claims 1 to 3, wherein the closure device is a protective cap. The stop portion is arranged close to one end of the second connecting rod hinged with the transmission connecting rod, for being blocked with one end of the second connecting rod hinged with the transmission connecting rod.

8. The cover opening and closing device according to any one of claims 1 to 3, wherein The second connecting rod is hinged at the end of the protective cover away from the rotation axis of the protective cover.

9. The cover opening and closing device according to any one of claims 1 to 3, wherein The transmission connecting rod comprises a third connecting rod and a fourth connecting rod hinged together.

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