A rotating shaft linkage mechanism

Abstract

A pivot linkage mechanism, including linkage wheel assembly, guide wheel assembly, linkage rope, hinge assembly, pre-tightening force adjusting device. In the unfolding stage, the pre-tightening force adjusting device tightens the linkage rope, the linkage rope rotates around the guide wheel to pull the linkage wheel to rotate, and after the linkage wheel rotates 96 degrees around the pivot, the small spring pushes to lock the linkage wheel and the pivot to prevent relative displacement. The lock pin unlocking state is achieved by pushing the lock pin into the linkage wheel by the large spring, thereby unlocking the linkage wheel and the support, synchronously locking the linkage wheel and the pivot for the second time, unlocking the whole linkage device, rotating the linkage mechanism around the hinge assembly, and pulling the linkage rope through the two guide wheels to pull the linkage wheel assembly. The linkage wheel and the pivot are locked and can rotate synchronously to realize the linkage function. Compared with the prior art, the device is locked by the cooperation between the lock pin, the lock tongue and the linkage wheel, the structure is simple, and only the spring pushing can realize the firm locking between the linkage wheel and the pivot, realize the linkage function, and the space utilization rate is high.

Description

Technical Field

[0001] This invention relates to a mechanical device, specifically a rotating shaft linkage mechanism. Background Technology

[0002] Addressing the design needs of space mechanisms and given the increasing number of space exploration activities, this paper proposes a design scheme for a large-scale space transfer mechanism to meet the demand for more mechanisms for space transfer. To ensure space saving and a lighter, smaller size during the transfer process, the linkage device of the transfer mechanism is designed to be rope-driven and precisely controllable.

[0003] To meet the mission requirements of the space transfer mechanism and for its dual-axis structure, a rotating shaft linkage mechanism is designed. This mechanism enables the linkage wheel to rotate relative to the rotating shaft under the pull of the rope during startup. When a certain position is reached, the linkage wheel and the rotating shaft lock together. As rotation continues, the rotating shaft and the linkage wheel rotate synchronously under the pull of the rope to achieve the linkage function.

[0004] The rotating shaft linkage mechanism developed to address the above problems should be highly versatile, simple in structure, small in size, easy to use, and capable of fulfilling the functional requirements of linkage limit and free rotation.

[0005] A search of existing technologies revealed that patent document CN1878640A discloses a linkage device for a linkage mechanism. This solution uses a fixed structure to change the rotation direction of the linkage mechanism. When applied to a space mechanism, it is not convenient for the folding and unfolding of the transfer mechanism, and its large size is not conducive to the movement of the entire transfer mechanism. Patent document CN107422782A discloses a linkage mechanism for a laptop computer, which is only suitable for scenarios with small rotation angles. In a space transfer mechanism, if the rotation angle of the shaft is to be reduced, the rotation radius needs to be increased, which increases the size of the entire mechanism and is not conducive to the execution of space tasks. Patent document CN103662966A discloses a four-axis linkage device for a winding machine, which mainly uses bearings to control the rotation of the four axes. Using bearings cannot restrict the relative rotation of the shaft and the linkage wheel, and cannot guarantee that the transfer mechanism can be released while ensuring the rotation of the shaft. Summary of the Invention

[0006] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a rotating shaft linkage mechanism. By using the locking tongue and the linkage wheel to lock each other during the rotation of the linkage wheel, the linkage wheel and the unfolding shaft are linked. A mechanism capable of completing the linkage of two rotating shafts is designed. The mechanism has a simple structure, fast operation, and high space utilization.

[0007] This solution uses a locking tongue and a linkage wheel to release the locking pin and lock the linkage wheel and the shaft, thereby achieving simultaneous rotation and release of the transfer mechanism. Only a small preload is required to ensure the stability of the device structure under the launch and pressing state. At the same time, this device is assembled on both sides of the transfer mechanism, which has high space utilization, small weight, and simple and reliable structure.

[0008] The technical solution provided in this application is as follows:

[0009] A rotating shaft linkage mechanism is connected to the end of an unfolding shaft, which is rotatably connected to a composite frame. The mechanism includes a support, a rotating shaft, a linkage wheel, a first locking device, and a second locking device. The support is fixedly connected to the composite frame. The rotating shaft is inserted into the inner hole of the support and rotatably connected to it. The rotating shaft is located at one end of the unfolding shaft and is coaxially fixed with it. The rotating shaft passes through the inner hole of the linkage wheel, which is located on the side of the support away from the unfolding shaft. The first locking device includes a locking tongue and a second elastic element. The locking tongue is slidably connected to the rotating shaft along its radial direction. A locking tongue slot is provided on the inner wall of the linkage wheel. The second elastic element drives the locking tongue to move into the locking tongue slot. In the initial state, the linkage wheel is locked to the composite frame via the second locking device. When the second elastic element drives the locking tongue to insert into the locking tongue slot, the second locking device locks the linkage wheel to the rotating shaft.

[0010] The second locking device includes a locking pin and a first elastic element, which are located between the rotating shaft and the support. One end of the first elastic element contacts the inner wall of the support and the other end contacts the end of the locking pin to push the locking pin to move closer to the linkage wheel. The support is provided with a limit groove, the inner wall of the linkage wheel is provided with a first half groove, and the end of the rotating shaft away from the unfolding shaft is provided with an annular step, and a second half groove is provided on the annular step.

[0011] In the initial state, the locking pin is simultaneously located in the limiting groove and the first half groove, and the end of the locking pin is in contact with the step surface of the annular step. The rotating shaft and the unfolding shaft rotate until the first half groove and the second half groove are aligned to form a slot hole that mates with the locking pin. The locking pin is pushed into the slot hole and disengages from the limiting groove. At this time, the rotating shaft locks with the linkage wheel.

[0012] When the latch and the latch slot are aligned, the first half slot and the second half slot are aligned.

[0013] The locking pin includes a ring frame and multiple pins. The pins are fixedly connected to the ring frame and are evenly distributed along the circumferential direction of the ring frame. The ring frame is sleeved on the outside of the rotating shaft, and the support is sleeved on the outside of the ring frame. The pins cooperate with the limiting groove and the first half groove.

[0014] The width of the limiting groove along the circumferential direction of the support is greater than the diameter of the pin.

[0015] The width of the limiting groove along the circumferential direction of the support is 1.5 to 2 times the diameter of the pin.

[0016] The end of the rotating shaft away from the unfolding shaft passes through the linkage wheel, and a protrusion is provided on the outside of the end of the rotating shaft that passes through the linkage wheel. The protrusion is located on the outside of the end of the linkage wheel away from the support.

[0017] The outer wall of the linkage wheel is provided with a limit block, which is located on the rotation path of the protrusion.

[0018] Both the first and second half-grooves are semi-cylindrical grooves.

[0019] In summary, this application includes at least the following beneficial technical effects:

[0020] (1) In response to the needs of the rotating shaft linkage task in space, a rotating shaft linkage mechanism was designed, which combines the rotating shaft of the space transfer mechanism with the rope drive method. The device has a simple structure, small size and high space utilization.

[0021] (2) The locking tongue is pushed into the groove of the linkage wheel by the spring, thereby releasing the locking pin to restrict the relative rotation of the linkage wheel and the shaft, thus completing the linkage function of the shaft and the linkage wheel. At the same time, the relative rotation angle between the linkage wheel and the shaft can also be limited according to the setting of the linkage wheel groove, which is convenient for precise control.

[0022] (3) The preload adjustment device applies preload to the linkage wheel through the linkage rope, which can ensure that the locking pin does not pop out. The whole device has high reliability and the double locking structure of the locking tongue and locking pin is more stable. Attached Figure Description

[0023] Figure 1 This is a front view schematic diagram of the single-drive self-weight transfer device in this embodiment;

[0024] Figure 2 This is a side view schematic diagram of the single-drive self-weight transfer device in this embodiment;

[0025] Figure 3 This is the initial state of the single-drive self-weight transfer device in this embodiment;

[0026] Figure 4 This is the deployed state of the single-drive self-weight transfer device in this embodiment;

[0027] Figure 5 This is the pressed and unlocked state of the single-drive self-weight transfer device in this embodiment;

[0028] Figure 6 This is the end-of-transfer state of the single-drive gravity transfer device in this embodiment;

[0029] Figure 7 This is the separated and released state of the single-drive gravity transfer device in this embodiment;

[0030] Figure 8This is a schematic diagram of the overall structure of the single-drive self-weight transfer device in this embodiment;

[0031] Figure 9 This is a schematic diagram of the linkage wheel in the pressed-in state;

[0032] Figure 10 This is a cross-sectional view of the linkage wheel assembly;

[0033] Figure 11 This is an exploded view of the linkage wheel assembly;

[0034] Figure 12 This is a schematic diagram showing the sequence of states: the linkage wheel is pressed down, the bolt is triggered, and the locking pin is triggered.

[0035] Figure 13 This is a structural diagram of the linkage components;

[0036] Figure 14 This is a schematic diagram of the linkage wheel structure.

[0037] Explanation of reference numerals: 1-Lander; 11-Hinge bracket; 2-Rover; 3-Drive release assembly; 4-Forced detachment device;

[0038] 9-Composite frame; 91-Compression release device; 92-Connection and separation device; 93-Support rod;

[0039] 5-Expanding axis;

[0040] 41-Cam; 42-Linkage rope;

[0041] 61-Sliding block; 62-Guide sleeve; 63-Nut;

[0042] 71-Locking pin; 711-Ring frame; 712-Pin shaft; 72-Linkage wheel; 721-First half groove; 722-Lock tongue slot; 73-Lock tongue; 74-Support; 741-Limit groove; 75-Large spring; 76-Rotating shaft; 761-Second half groove; 77-Small spring; 78-Lock tongue mounting base. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0044] A single-drive gravity transfer device for a rover, connected to one side of the lander 1, is used to connect the rover 2 to the lander 1, such as... Figure 1 As shown, it includes a composite frame 9, a drive-release assembly 3, a linkage wheel assembly, and a linkage assembly.

[0045] The linkage wheel assembly is a rotating shaft linkage mechanism disclosed in this application embodiment.

[0046] Lander 1 is fixedly connected to hinge bracket 11. One end of composite frame 9 is rotatably connected to hinge bracket 11. Composite frame 9 is equipped with clamping release device 91, which can be controllably connected to or separated from lander 1. The other end of composite frame 9 is rotatably connected to deployment shaft 5. Deployment shaft 5 is connected to connection and separation device 92, which rotates with deployment shaft 5 and is used to connect rover 2. Linkage wheel assembly is located at both ends of deployment shaft 5. Linkage assembly includes cam 41 and linkage rope 42. Cam is fixedly connected to hinge bracket 11. One end of linkage rope is connected to linkage wheel assembly and the other end is connected to cam, coupling two degrees of freedom into one degree of freedom. This enables the composite frame 9 to rotate in a direction away from lander 1 (clockwise rotation) during the transfer process, while deployment shaft 5 can only rotate counterclockwise.

[0047] In the initial state, the clamping release device 91 is fixed to the lander 1, and in the first state, the clamping release device 91 is separated from the lander 1. After the clamping release device 91 is separated from the lander 1, the composite frame 9 can rotate relative to the hinge bracket 11, thereby lowering the rover. In the initial state, the hinge bracket 11 and the clamping release device 91 form a four-point clamping between the composite frame 9 and the lander 1 to ensure the stability of the mechanism. At this time, the deployment shaft 5 is located above the hinge shaft between the composite frame 9 and the hinge bracket 11. During the transfer of the rover 2, the clamping release device 91 is separated from the lander 1, and the composite frame 9 can rotate clockwise around the hinge bracket 11.

[0048] The composite frame 9 is the main structure of the entire transfer device. Metal joints are reserved at the top and bottom of the composite frame 9 for connection with other components.

[0049] A support rod 93 is fixedly connected to the middle of the deployment shaft 5. The drive and release assembly 3 includes a motor 31, a pulley, and a release steel wire rope 3. The motor is fixedly connected to the lander 1. One end of the release steel wire rope is connected to the pulley, and the other end is connected to the support rod 93. The motor drives the pulley to rotate. When the pulley retracts the release steel wire rope, the release steel wire rope pulls the deployment shaft 5, the separation device 92, and the rover 2 together through the support rod 93 until the rover 2 is in the deployed state. In the deployed state, the rover 2 is in a horizontal position. This process is the deployment process of the rover 2. At this time, the linkage wheel assembly is locked to the deployment shaft 5. Then, the motor controls the release of the release steel wire rope, and the composite frame 9 rotates away from the lander 1, realizing the transfer of the rover 2. The forward and reverse rotation of the motor controls the release and retraction of the release steel wire rope, realizing the speed control of the transfer deployment and transfer process, and completing the deployment, transfer, and mechanism retraction actions of the rover 2. Figures 3-7 As shown, Figure 3 It is in launch mode. Figure 4 This is the unfolded state. Figure 5 It is in the process of transitioning. Figure 6The transfer is complete. Figure 7 This is the initial recovery state (at which point the probe and transfer mechanism have separated).

[0050] like Figure 10 and Figure 11 As shown, the composite frame 9 is equipped with a linkage wheel assembly, which includes a locking pin 71, a linkage wheel 72, a locking tongue 73, a support 74, a large spring 75, a rotating shaft 76, and a small spring 77. The rotating shaft 76 is coaxial with and fixed to the unfolding shaft 5, so that the unfolding shaft 5 drives the rotating shaft 76 to rotate together. The support 74 is fixedly connected to the composite frame 9. The rotating shaft 76 is inserted into the inner hole of the support 74 and rotatably connected to the support 74. At the same time, the rotating shaft 76 passes through the inner hole of the linkage wheel 72. The linkage wheel 72 is located on the side of the support 74 away from the unfolding shaft 5.

[0051] like Figure 11 and Figure 14 As shown, the locking pin 71 includes an annular frame 711 and multiple cylindrical pins 712. The pins 712 are fixedly connected to the annular frame 711 and are evenly distributed along the circumferential direction of the annular frame 711. In this embodiment, three pins 712 are provided. The locking pin 71 and the large spring 75 are located between the pivot 76 of the support 74. One end of the large spring 75 contacts the support 74 and the other end contacts the locking pin 71 to push the locking pin 71 to move towards the linkage wheel 72. The support 74 is provided with a limiting groove 741 at one end near the linkage wheel 72. In the initial state, the pin 712 is located in the limiting groove 741. The limiting groove 741 is used to limit the pin 712, so that the locking pin 71 does not rotate with the rotating shaft 76. At the same time, the inner wall of the linkage wheel 72 is provided with a first half groove 721. The pin 712 is locked in the first half groove 721. The pin 712 is locked in both the limiting groove 741 and the first half groove 721, so that the linkage wheel 72 does not rotate with the rotating shaft 76.

[0052] like Figure 12 As shown, an annular step is provided at the end of the rotating shaft 76 away from the unfolding shaft 5. A second half-groove 761 is provided on the annular step. Both the first half-groove 721 and the second half-groove 761 are semi-cylindrical grooves. In the initial state, the end of the pin 712 is in contact with the step surface of the annular step, and the rotating shaft 76 is driven to rotate by the unfolding shaft 5 until the inspector 2 is in the unfolded state. At this time, the first half-groove 721 and the second half-groove 761 are aligned to form a cylindrical groove that cooperates with the pin 712. At this time, the locking pin 71 is pushed into the cylindrical groove and the locking pin is disengaged from the limiting groove 741. At this time, the rotating shaft 76 is locked with the linkage wheel 72, and the linkage wheel 72 rotates together with the rotating shaft 76, thereby realizing the linkage function.

[0053] A latch mounting seat is installed on the inner side of the end of the rotating shaft 76. A groove is provided on the latch mounting seat, with its length along the radial direction of the rotating shaft 76. The latch 73 is located within the groove and can slide along its length. A small spring 77 connects the latch 73 and the latch mounting seat, driving the latch 73 to move along the length of the groove. The rotating shaft 76 has a through hole facing the end of the groove, and a latch slot 722 is also provided on the inner wall of the linkage wheel 72. When the first half-groove 721 and the second half-groove 761 are aligned to form a cylindrical groove, the latch 73 is aligned with the latch slot 722. At this time, the small spring 77 drives the latch 73 to pass through the through hole and engage in the latch slot 722.

[0054] Because the unfolding shaft 5 is connected to the inspector 2, meaning the unfolding shaft 5 bears a large load, it may deform, causing a certain deviation in the position of the locking pin 71. This can lead to the locking pin 71 getting stuck, preventing it from immediately engaging in the cylindrical groove when the first half-groove 721 and the second half-groove 761 are aligned. Furthermore, during the rotation of the rotating shaft 76, friction causes the locking pin 71 to press against one side of the limiting groove 741, resulting in significant friction on one side of the locking pin 71 and making it prone to jamming. This again prevents the locking pin 71 from immediately engaging in the cylindrical groove when the first half-groove 721 and the second half-groove 761 are aligned. However, the movement of the locking tongue 73 is not affected by the deformation of the unfolding shaft 5. When the locking tongue 73 is aligned with the locking tongue slot 722, the locking tongue 73 first engages in the locking tongue slot 722, and then the pin 712 is inserted into the cylindrical groove.

[0055] Further configuration: The limiting groove 741 is designed as an elongated groove, meaning the width of the limiting groove 741 along the circumferential direction of the support 74 is greater than the diameter of the pin 712. Specifically, the width of the limiting groove 741 along the circumferential direction of the support 74 is 1.5 to 2 times the diameter of the pin. When the unfolding shaft 5 begins to rotate in the reverse direction, the force pressing between the pin 712 and one side of the limiting groove 741 is released, and the pin 712 is driven by the large spring 75 to insert into the cylindrical groove. This configuration ensures that the locking pin 71 can be engaged in the cylindrical groove; and the mating structure between the pin 712 and the cylindrical groove allows it to withstand greater torque, thereby ensuring that the rotating shaft 76 and the linkage wheel 72 rotate together.

[0056] That is, when in the unfolded state, the unfolding shaft 5, the rotating shaft 76 and the linkage wheel 72 rotate together.

[0057] The end of the rotating shaft 76 away from the unfolding shaft 5 extends through the linkage wheel 72. A protrusion is provided on the outside of the end of the rotating shaft 76 that extends through the linkage wheel 72. The protrusion is located on the outside of the end of the linkage wheel 72 away from the support 74. A limit block is provided on the outer wall surface of the linkage wheel 72. The limit block is located on the rotation path of the protrusion. The protrusion prevents the linkage wheel 72 from slipping off the rotating shaft 76, and the limit block cooperates with the protrusion to limit the rotation stroke of the rotating shaft 76.

[0058] like Figure 13As shown, the hinge bracket 11 is connected to a cam and a preload adjustment device. One end of the linkage rope is fixedly connected to the outer side of the linkage wheel 72, and the other end is connected to the preload adjustment device, which is used to preload the linkage rope. The cam is fixedly connected to the hinge bracket 11, and the axis of the cam is parallel to the rotation axis of the composite frame 9. An upper guide wheel and a lower guide wheel are also rotatably connected to the composite frame 9. The linkage wheel 72, the upper guide wheel, the lower guide wheel, and the cam are arranged sequentially on the side of the composite frame 9. The linkage rope passes around the cam from the side of the cam closest to the lander 1, passes around the lower guide wheel from the side of the lower guide wheel away from the lander 1, passes around the upper guide wheel from the side of the upper guide wheel away from the lander 1, passes around the linkage wheel 72 from the side of the linkage wheel 72 closest to the lander 1, and is fixedly connected to the outer wall of the linkage wheel 72. The straight line of the linkage rope between the upper guide wheel and the cam passes through the axis of the linkage wheel 72, so that the force exerted on the linkage wheel 72 by the linkage rope is perpendicular to the axis of the linkage wheel 72, and there is no torque on the linkage wheel 72 in the circumferential direction.

[0059] When the composite frame 9 rotates, the linkage rope is wound around the outer curved surface of the cam, while the linkage rope on the outer curved surface of the upper guide wheel is released. Thus, when the composite frame 9 moves away from the rotating lander 1, the upper guide wheel, cam, and linkage rope drive the deployment shaft 5 to rotate in the opposite direction, and the rotation angle of the deployment shaft 5 is the same as the rotation angle of the composite frame 9. Therefore, during the rotation of the composite frame 9, the rover 2 connected to the deployment shaft 5 can maintain a stable horizontal state.

[0060] The curve of the cam satisfies the following: when the composite frame 9 rotates, the rotation angle of the composite frame 9 around the hinge axis is consistent with the rotation angle of the linkage wheel 72 (opposite in direction), and the patrol device 2 remains horizontal.

[0061] The preload adjustment device includes a sliding block, a guide sleeve, and a nut. The guide sleeve is fixedly connected to the hinge bracket 11. The sliding block passes through the guide sleeve and is slidably connected to it. A long strip groove is provided on one side of the guide sleeve. The sliding block has a protrusion located in the long strip groove. One end of the sliding block is fixed to the linkage rope, and the other end extends out of the guide sleeve. The nut is threadedly connected to the end of the sliding block that extends out of the guide sleeve. When the nut is rotated, the sliding block moves within the guide sleeve, thereby adjusting the preload of the linkage rope.

[0062] One end of the forced disconnect device 4 is mounted on the deployment shaft 5, and the other end is connected to the rover 11. In the event that the electric disconnect function of the disconnect connector of the rover 2 fails, the forced disconnect device 4 achieves mechanical separation of the disconnect plug located at the lander 1 end from the socket at the rover 2 end.

[0063] The implementation principle of this patent is as follows:

[0064] Initially, the linkage wheel assembly is in a compressed state. At this time, the first and second semi-cylindrical slots are not aligned. One end of the locking pin 71 is pressed by the large spring, so that the locking pin 71 contacts the annular step of the rotating shaft 76. The small spring 77 presses the locking tongue 73, so that the locking tongue 73 contacts the inner wall of the linkage wheel 72. After the unfolding shaft 5 starts to rotate, the unfolding shaft 5 drives the rotating shaft 76 to rotate together. At this time, the linkage wheel 72 and the support 74 cannot rotate relative to each other, so the rotating shaft 76 and the linkage wheel 72 rotate relative to each other. Until the linkage wheel 72 rotates 96°, the small spring 77 pushes the locking tongue 73 into the locking tongue slot 722 of the linkage wheel 72. The small spring 77 pushes the locking tongue 73 to the limit position and applies a force to the linkage wheel 72. The linkage wheel 72 receiving this force is the locking signal.

[0065] When the locking tongue 73 is pushed into the locking tongue slot 722 of the linkage wheel 72 by the small spring 77, it is in the locking tongue triggered state. At this time, the first semi-cylindrical groove and the second semi-cylindrical groove are aligned to form a cylindrical groove. Then, the large spring 75 pushes the locking pin 71 into the cylindrical groove of the linkage wheel 72. The linkage wheel 72 is locked to the rotating shaft 76 through the locking pin 71 and the locking tongue 73. At this time, the linkage wheel 72 and the rotating shaft 76 rotate synchronously.

[0066] Furthermore, since the linkage rope is wound on the same side of the linkage wheel 72 and the cam, when the composite frame 9 rotates as a whole, causing the linkage rope to be wound around the outside of the cam, the linkage on the outside of the linkage wheel 72 is released, that is, the linkage wheel 72 and the composite frame 9 rotate in opposite directions, and the device completes the linkage function.

[0067] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0068] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A rotating shaft linkage mechanism, connected to the end of an unfolding shaft (5), the unfolding shaft (5) being rotatably connected to a composite frame (9), characterized in that: Includes a support (74), a rotating shaft (76), a linkage wheel (72), a first locking device, and a second locking device; The support (74) is fixedly connected to the composite frame (9), and the rotating shaft (76) is inserted into the inner hole of the support (74) and rotatably connected to the support (74). The rotating shaft (76) is located at one end of the unfolding shaft (5) and is fixed coaxially with the unfolding shaft (5). The rotating shaft (76) passes through the inner hole of the linkage wheel (72), and the linkage wheel (72) is located on the side of the support (74) away from the unfolding shaft (5). The first locking device includes a locking tongue (73) and a second elastic element. The locking tongue (73) is slidably connected to the rotating shaft (76) along the radial direction of the rotating shaft (76). The inner wall of the linkage wheel (72) is provided with a locking tongue slot (722). The second elastic element is used to drive the locking tongue (73) to move in the direction of extending into the locking tongue slot (722). In the initial state, the linkage wheel (72) is locked to the composite frame (9) by the second locking device. When the second elastic element drives the locking tongue (73) to insert into the locking tongue slot (722), the second locking device locks the linkage wheel (72) to the rotating shaft (76). The second locking device includes a locking pin (71) and a first elastic element. The locking pin (71) and the first elastic element are located between the rotating shaft (76) and the support (74). One end of the first elastic element contacts the inner wall of the support (74) and the other end contacts the end of the locking pin (71) to push the locking pin (71) to move closer to the linkage wheel (72). The support (74) has a limiting groove (741). The inner wall of the linkage wheel (72) is provided with a first half groove (721). The end of the rotating shaft (76) away from the unfolding shaft (5) is provided with an annular step. The annular step is provided with a second half groove (761). In the initial state, the locking pin (71) is simultaneously located in the limiting groove (741) and the first half groove (721), and the end of the locking pin (71) is in contact with the step surface of the annular step; the rotating shaft (76) and the unfolding shaft (5) rotate until the first half groove (721) and the second half groove (761) are aligned to form a slot that engages with the locking pin (71), the locking pin (71) is pushed into the slot, and the locking pin (71) disengages from the limiting groove (741), at which point the rotating shaft (76) is locked with the linkage wheel (72).

2. The rotating shaft linkage mechanism according to claim 1, characterized in that: When the latch (73) is aligned with the latch slot (722), the first half slot (721) and the second half slot (761) are aligned.

3. The rotating shaft linkage mechanism according to claim 1, characterized in that: The locking pin (71) includes a ring frame (711) and multiple pins (712). The pins (712) are fixedly connected to the ring frame (711). The pins (712) are evenly distributed along the circumferential direction of the ring frame (711). The ring frame (711) is sleeved on the outside of the rotating shaft (76). The support (74) is sleeved on the outside of the ring frame (711). The pins (712) cooperate with the limiting groove (741) and the first half groove (721).

4. The rotating shaft linkage mechanism according to claim 1, characterized in that: The width of the limiting groove (741) along the circumferential direction of the support (74) is greater than the diameter of the pin (712).

5. The rotating shaft linkage mechanism according to claim 1, characterized in that: The width of the limiting groove (741) along the circumferential direction of the support (74) is 1.5 to 2 times the diameter of the pin (712).

6. The rotating shaft linkage mechanism according to claim 1, characterized in that: The end of the rotating shaft (76) away from the unfolding shaft (5) passes through the linkage wheel (72). A protrusion is provided on the outside of the end of the rotating shaft (76) that passes through the linkage wheel (72). The protrusion is located on the outside of the end of the linkage wheel (72) away from the support (74).

7. A rotating shaft linkage mechanism according to claim 6, characterized in that: The outer wall of the linkage wheel (72) is provided with a limit block, which is located on the rotation path of the protrusion.

8. The rotating shaft linkage mechanism according to claim 1, characterized in that: Both the first half-groove (721) and the second half-groove (761) are semi-cylindrical grooves.

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