A self-locking folding joint

Abstract

A self-locking folding joint disclosed by the present invention comprises a lower joint, an upper joint and a locking mechanism. Lugs are respectively arranged on the left and right sides of the upper joint, and a central shaft passes through the lugs and the lower joint for hinged connection. A window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint. A slider in the locking mechanism is arranged in the window. The lower edge of the front part of the upper joint is attached to the upper surface of the slider, and the upper edge of the front part of the lower joint is attached to the lower surface of the slider. The rear part of the lower joint abuts against the rear part of the upper joint. The locking mechanism has a handle, an adjusting rod and a slider. The handle is arranged on the outer side of the joint. The handle can drive the slider to move back and forth through the adjusting rod so that the slider is inserted into or withdrawn from the window. The self-locking folding joint is convenient to process and assemble, firm and reliable, and can realize self-locking.

Description

Technical Field

[0001] The present invention relates to a self-locking folding joint, and particularly to a self-locking folding joint applicable to a riding vehicle. Background Art

[0002] The whole world is advocating energy conservation and emission reduction. China is well-deserved a big country in bicycles and electric vehicles. Folding bikes have become a very important type of bicycles due to their convenient carrying and small occupied space, and there is an increasingly popular trend.

[0003] Currently, most existing folding bikes are provided with folding joints in the middle of the frame or the vertical tube. For example, Chinese Patent CN01127832.3 discloses an "inner-locking self-locking folding joint", in which one side of two connecting plates is hinged, there are concave platforms on the mating surfaces of the connecting plates, and clamping grooves are formed at the edges of the concave platforms. A movable clamping block is arranged in the concave platform of one connecting plate, and the side surface of the clamping block is V-shaped and can be inserted into the clamping grooves of the two connecting plates after being closed, and the closed connecting plates are clamped and fixed inside the connecting plates. Although this solution has the advantage of a hidden locking mechanism, it has relatively high requirements for the machining accuracy and strength of the front end of the clamping block and the rotating part of the handle, otherwise it is easy to clamp loosely; in addition, a large angle of the handle needs to be turned to lock or open the joint, that is, turning the handle and folding the connecting plate are two independent actions, lacking interactivity.

[0004] Due to considerations for the safety of riders, it is an irresistible trend that some countries or regions are adopting increasingly strict industry standards. How to enhance the safety and operability of the folding joints of riding vehicles is a problem to be solved. Summary of the Invention

[0005] The present invention aims to provide a self-locking folding joint with a simple structure, reliable locking, and easy operation.

[0006] The present invention is realized as follows: A self-locking folding joint includes a lower joint, an upper joint, and a locking mechanism. Lugs are respectively arranged on the left and right sides of the upper joint, and a central shaft passes through the lugs and the lower joint for hinged connection; a window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint, and a slider in the locking mechanism is arranged in the window. The lower edge of the front part of the upper joint is attached to the upper surface of the slider, and the upper edge of the front part of the lower joint is attached to the lower surface of the slider; the rear part of the lower joint abuts against the rear part of the upper joint; the locking mechanism has a handle, an adjusting rod, and a slider. The handle is arranged outside the joint, and the handle can drive the slider to move back and forth through the adjusting rod, so that the slider is inserted into or withdrawn from the window.

[0007] The lower joint has an upper edge at the rear part, the upper joint has a lower edge at the rear part, and the lower edge at the rear part of the upper joint abuts against the upper edge at the rear part of the lower joint.

[0008] The lower joint is provided with grooves on both the left and right sides, and the lug in the upper joint is accommodated in the groove; the back of the groove is located at the rear of the lower joint and abuts against the rear side of the lug.

[0009] An included angle exists between the upper surface and the lower surface of the slider.

[0010] The adjusting rod includes an accessory transmission rod connected by threads. An opening is provided at the rear of the lower joint. The tail end of the accessory transmission rod is hinged to the handle through the opening, and the front end of the adjusting rod is fixedly connected to the slider.

[0011] A surrounding boss is provided in the middle of the adjusting rod. A spring is sleeved on the adjusting rod. The front end of the spring abuts against the boss, and the rear end of the spring abuts against the inner wall at the rear of the lower joint.

[0012] The lower joint has a hollow inner cavity, and a central shaft passes through the inner cavity; a hook spring is provided in the inner cavity. The lower end of the hook spring is connected to the central shaft, and the upper end of the hook spring is connected to the adjusting rod.

[0013] The upper end inside the upper joint is hollow, and a plug is provided inside the upper end of the upper joint. The lower side of the plug is an inwardly concave arc surface.

[0014] A slit is provided at the rear of the lower joint. A convex rib is provided on the front side of the lower part of the handle, and the convex rib extends into the slit. A first hinge shaft passes through the lower joint and the convex rib for connection; a convex column is provided on the front side of the middle part of the handle and is hinged to the tail end of the adjusting rod through a second hinge shaft by means of the accessory transmission rod on the adjusting rod; the axis lines of the first hinge shaft and the second hinge shaft are respectively parallel to the axis line of the central shaft.

[0015] An opening is provided at the rear of the lower joint. The tail end of the adjusting rod is fixedly connected to the handle through the opening, and the front end of the adjusting rod is fixedly connected to the slider.

[0016] The handle is connected to the tail end of the adjusting rod. A nut is sleeved on the adjusting rod. The rear side of the nut abuts against the front side of the handle, and the front side of the nut abuts against the outer side at the rear of the lower joint; the front end of the adjusting rod is threadedly connected to the slider; a surrounding boss is provided in the middle of the adjusting rod, and the boss abuts against the inner wall at the rear of the lower joint.

[0017] The handle is a set of components, including a spring, a push rod, a rocker arm, and a pin shaft; the handle is fixedly connected to the tail end of the push rod. A spring is sleeved on the push rod. One large-end part of the push rod presses against the front side of the rocker arm tightly. The pin shaft is inserted through the perforations at the upper end of the rocker arm and the perforations at the upper end of the plug; the front end of the adjusting rod is fixedly connected to the slider, and the tail end of the adjusting rod is sleeved in the hole at the rear of the lower joint; a pin is provided on the side of the hole at the rear of the lower joint and is matched with the long groove on the side of the adjusting rod.

[0018] The slider of the self-locking folding joint of the present invention is arranged within the window formed by the lower joint and the upper joint. The rear part of the lower joint abuts against the rear part of the upper joint, such that when in the locked state, the upper joint and the lower joint cannot rotate forward or backward, being stable and reliable. The spring is sleeved on the adjusting rod, with the front end of the spring abutting against the boss and the rear end of the spring abutting against the inner wall of the rear part of the lower joint, such that the slider is pushed to achieve automatic locking, simplifying the operation steps of the user and greatly improving the safety of the self-locking folding joint of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is an exploded view of the first embodiment of the self-locking folding joint of the present invention;

[0020] Figure 2 is an exploded view of the first embodiment of the self-locking folding joint of the present invention from another angle;

[0021] Figure 3 is a three-dimensional schematic diagram of the locked state of the first embodiment of the self-locking folding joint of the present invention;

[0022] Figure 4 is a three-dimensional schematic diagram of the locked state of the first embodiment of the self-locking folding joint of the present invention from another angle;

[0023] Figure 5 is a schematic diagram of the intermediate folding state of the first embodiment of the self-locking folding joint of the present invention;

[0024] Figure 6 is another schematic diagram of the intermediate folding state of the first embodiment of the self-locking folding joint of the present invention;

[0025] Figure 7 is a schematic cross-sectional view of the locked state of the first embodiment of the self-locking folding joint of the present invention;

[0026] Figure 8 is a schematic cross-sectional view of the intermediate folding state of the first embodiment of the self-locking folding joint of the present invention;

[0027] Figure 9 is a three-dimensional schematic diagram of the folded state of the first embodiment of the self-locking folding joint of the present invention;

[0028] Figure 10 is another three-dimensional schematic diagram of the folded state of the first embodiment of the self-locking folding joint of the present invention;

[0029] Figure 11 is a three-dimensional schematic diagram of the upper and lower joints of the first embodiment of the self-locking folding joint of the present invention;

[0030] Figure 12 is a schematic diagram of the rear part of the upper joint of the first embodiment of the self-locking folding joint of the present invention;

[0031] Figure 13 Schematic diagram of the state of the slider when the joint of the first embodiment of the self-locking folding joint of the present invention is locked;

[0032] Figure 14 Exploded view of the second embodiment of the self-locking folding joint of the present invention;

[0033] Figure 15 Schematic cross-sectional view of the locked state of the second embodiment of the self-locking folding joint of the present invention;

[0034] Figure 16 Exploded view of the third embodiment of the self-locking folding joint of the present invention;

[0035] Figure 17 Schematic cross-sectional view of the locked state of the third embodiment of the self-locking folding joint of the present invention;

[0036] Figure 18 Exploded view of the fourth embodiment of the self-locking folding joint of the present invention;

[0037] Figure 19 Another perspective exploded view of the fourth embodiment of the self-locking folding joint of the present invention:

[0038] Figure 20 Schematic cross-sectional view of the locked state of the fourth embodiment of the self-locking folding joint of the present invention;

[0039] Figure 21 Schematic cross-sectional view of the intermediate folding state of the fourth embodiment of the self-locking folding joint of the present invention. Detailed implementation manners

[0040] The following combines Figures 1 to 21 to further elaborate on the self-locking folding joint of the present invention in detail.

[0041] As Figures 1 to 13 shown in the first embodiment of the present invention, the self-locking folding joint of this solution includes a lower joint 1, an upper joint 2, and a locking mechanism. The left and right sides of the upper joint are each provided with lugs 21. The central shaft 3 passes through the lugs and the middle part of the lower joint and is hinged and connected, and is locked by two screws 31; As Figure 5 shown, a window 12 is formed between the upper edge 101 of the front part of the lower joint and the lower edge 201 of the front part of the upper joint. The slider 6 in the locking mechanism is arranged in the window 12; As Figure 13 shown, the lower edge 201 of the front part of the upper joint is in contact with the upper surface 61 of the slider, and the upper edge 101 of the front part of the lower joint is in contact with the lower surface 62 of the slider; As Figure 4 and Figure 7 shown, the rear part of the lower joint is in contact with the rear part of the upper joint; As Figure 1 、 Figure 2 、 Figure 7 and Figure 8As shown, the locking mechanism has a handle 4, an adjusting rod 5, and a slider 6. The handle is arranged on the outer side of the rear part of the lower joint. The handle can drive the slider to move back and forth through the adjusting rod, so that the slider 6 can be inserted into or withdrawn from the window 12. Further, the adjusting rod 5 further includes an accessory transmission rod 55. An opening 103 is provided at the rear part of the lower joint. The tail end of the accessory transmission rod 55 in the adjusting rod 5 is connected to the handle 4 through the opening 103, and the front end of the adjusting rod 5 is fixedly connected to the slider 6 by a thread.

[0042] Further, as Figure 11 , 12 shown, the lower joint has an upper rear edge 102, and the upper joint has a lower rear edge 202. The lower rear edge 202 of the upper joint abuts against the upper rear edge 102 of the lower joint. The lower rear edge of the upper joint is located at the rear side of the roots of the two lugs. In contrast, the lower front edge of the upper joint is located at the front side of the roots of the two lugs. Another solution is that grooves 13 are provided on each of the left and right sides of the lower joint, and the lugs 21 are accommodated in the grooves 13. The back surface 132 of the groove is located at the rear part of the lower joint and abuts against the rear side surface 203 of the lug. The way the rear part of the lower joint abuts against the rear part of the upper joint includes at least one of the two solutions described here. Further, a first arc chamfer 105 is provided at the connection between the upper rear edge 102 of the lower joint and the back surface 132 of the groove, and a second arc chamfer 204 is provided at the connection between the lower rear edge 202 of the upper joint and the rear side surface 203 of the lug, which can further improve the compatibility when the rear part of the lower joint abuts against the rear part of the upper joint. The arc chamfer 204 and the arc chamfer 105 can be set to be in contact or not in contact, depending on the process.

[0043] As Figure 4 and Figure 7 shown, in the locked state, the lower front edge of the upper joint abuts against the upper surface of the slider, and the upper front edge of the lower joint abuts against the lower surface of the slider, so that the upper joint cannot be flipped forward; at the same time, the rear part of the lower joint abuts against the rear part of the upper joint, so that the upper joint cannot be flipped backward, forming a very stable mechanism. As Figure 5 , Figure 6 and Figure 10 shown, when the handle is pulled, the slider retreats until it exits the window. At this time, the upper joint can easily rotate forward around the central axis, and the operation is simple and reliable.

[0044] As Figure 1 and Figure 7 , 13As shown, the upper surface 61 and the lower surface 62 of the slider 6 form an angle, with the front end of the slider being thin and the tail end being thick. The front end of the slider refers to the opposite end away from the handle 4, and the tail end of the slider refers to the opposite end close to the handle 4. The purposes of the wedge-shaped slider include: the slider can automatically eliminate the gaps between the slider and the upper joint and the lower joint under the action of the spring 52. At the same time, when the upper joint and the lower joint are in the locked state, it can prevent the slider from protruding out of the outer surface of the self-locking folding joint under the action of the spring thrust, avoiding scratching and damage; when folding is required, the slider can move backward more labor-savingly and will not get stuck. At the same time, it can also effectively reduce the processing accuracy and save costs.

[0045] As Figure 1 and Figure 11 shown, the lower joint groove has a bottom surface 131, a back surface 132 and an inner side surface 133. The inner side surface 133 is a vertical plane, and the bottom surface and the back surface are connected by an arc chamfer; the inner wall 211 of the upper joint lug fits the inner side surface 133, and the lower part 212 of the lug is an arc edge. Further, the two grooves 13 are symmetrically arranged on the left and right sides of the lower joint 1, and the two lugs 21 of the upper joint 2 are symmetrically arranged left and right; the two inner side surfaces 133 of the grooves 13 are parallel planes. In this way, when the upper joint 2 rotates along the central axis 3 with the lower joint 1, the inner wall 211 of the upper joint 2 and the inner side surface 133 of the lower joint 1 always remain in a fitting state, and the rotation direction is stable and does not shake. The arc chamfer of the bottom surface and the back surface of the groove and the arc edge structure of the lower part of the lug make the upper joint 2 rotate forward more smoothly and labor-savingly.

[0046] The middle part of the adjusting rod has a surrounding boss 51, and the spring 52 is sleeved on the adjusting rod. The front end of the spring abuts against the boss 51, and the rear end of the spring abuts against the inner wall of the rear part of the lower joint. The function of this spring is to push the adjusting rod 5 forward by means of the surrounding boss, and then push the slider 6 to tightly press the upper joint and the lower joint until the gaps between the slider and the upper joint and the lower joint are eliminated. At the same time, because the tail end of the adjusting rod 5 pulls the handle 4, a return effect is generated on the handle.

[0047] As Figure 1 and Figure 7 、 8 shown, the lower joint 1 has a hollow inner cavity 11, and the central axis 3 passes through the inner cavity; a hook spring 53 is arranged in the inner cavity. The lower end of the hook spring 53 is connected to the central axis 3, and the upper end of the hook spring 53 is connected to the adjusting rod 5. When opening or closing the self-locking folding joint, the hook spring 53 makes the adjusting rod 5 and the slider 6 not move up and down during the movement, ensuring the stability of the slider 6 during the movement.

[0048] As Figures 7 to 10As shown, the interior of the upper joint 2 is hollow at its upper end. A plug 22 is provided inside the upper end of the upper joint. The lower side of the plug is an inwardly concave arc surface. During the rotation of the upper joint 2 towards the handle 4, that is, when the self-locking folding joint is in the state of being buckled and locked, the front edge 611 of the upper surface of the slider 6 will come into contact with the inwardly concave arc surface of the plug 22. At this time, if the upper joint 2 is rotated further, the front edge 611 will slide along the arc surface for a certain distance, and at the same time the slider will move backward, so that the upper joint 2 can continue to rotate upward. Finally, after the upper joint 2 is completely rotated straight upward, the slider 6 will be automatically pushed forward by the thrust of the spring 52 to reach the window 12, realizing the automatic tight connection between the upper joint 2 and the lower joint 1. The plug 22 makes the movement track of the slider 6 smoother and more controllable.

[0049] As Figure 1 , 2 As shown in Figures 7 and 8, the lower part of the handle is hinged to the lower joint through the first hinge shaft 14, and the middle part of the handle is hinged to the tail end of the accessory transmission rod 55 in the adjusting rod 5 through the second hinge shaft 54; the axis lines of the first hinge shaft and the second hinge shaft are respectively parallel to the axis line of the central shaft 3. Further, a convex column 42 is provided on the front side of the middle part of the handle, and the tail end of the transmission rod 55 in the adjusting rod is hinged to the convex column 42.

[0050] Both the front end and the tail end of the adjusting rod 5 have external threads, and the front end of its accessory transmission rod 55 has internal threads. The tail end of the adjusting rod 5 is threadedly connected to the transmission rod 55; the front end of the adjusting rod 5 is threadedly connected to the threaded hole on the back of the slider 6. This structural method can adjust the distance between the slider 6 and the handle 4 by rotating the adjusting rod 5, so as to achieve the best transmission and locking functions in the case of manufacturing errors of parts; in addition, during vehicle riding, due to road surface bumps and vibrations, parts may shift, and it can also be reasonably improved through fine adjustment. The front end and the tail end of the adjusting rod 5 can also be respectively connected to the slider and the transmission rod by means of screw fixation; in addition, the front end and the tail end of the adjusting rod 5 can also be respectively fixedly connected to the slider and the transmission rod by welding; or the transmission rod, the adjusting rod and the slider are made into one body, and their transmission functions are the same, but there is no fine adjustment effect.

[0051] As Figure 2As shown, a slit 104 is provided at the rear of the lower joint, and a ridge 41 is provided at the front side of the lower part of the handle. The ridge 41 extends into the slit 104, and the first hinge shaft 14 passes through the lower joint and the ridge to connect. The lower end of the slit extends to the bottom edge of the lower joint; the slit 104 is connected to the opening 103 at the rear of the lower joint, and this structure further reduces the difficulty of processing. Furthermore, a transverse hole 15 on the side wall of the lower joint passes through the slit, and the first hinge shaft 14 passes through the transverse hole 15 to connect the ridge 41 of the handle. The axis of the transverse screw 8 is parallel to the axis of the first hinge shaft 14, and the first hinge shaft 14 and the transverse screw 8 are threadedly connected to the lower joint, so that the lower joint can be tightly clamped on the front fork stem (not shown in the figure) of the vehicle in the locked state.

[0052] like Figure 3 , 7 As shown, the front side of the slider is an arc surface; in the locked state, the front side of the slider is flush with the outer surface of the lower joint and the outer surface of the upper joint. This is mainly to prevent the slider from convexly protruding and causing scratches, affecting operational safety; at the same time, in the locked state, the slider is visually integrated with the lower joint and the upper joint, and looks beautiful and streamlined.

[0053] Furthermore, the lower joint and the upper joint are cylindrical or elliptical, which is also required for the dual effects of beauty and safety. Of course, the lower joint and the upper joint can also be square or other shapes.

[0054] Furthermore, the lower end of the lower joint is fixedly connected to the front fork riser (not shown in the figure), and the upper end of the upper joint is fixedly connected to the handlebar riser 7.

[0055] Specific operation instructions: Figure 3 , 4 As shown, this is the locking state of the self-locking folding joint; Figure 5 As shown in the figure, when the self-locking folding joint needs to be opened, first pull the upper end of the handle backwards, and then the handle will pull the slider backwards through the adjustment rod; Figure 6 As shown in the figure, after the slider moves back a certain distance, the upper joint is rotated forward to achieve the following Figure 10 The folding effect, at this time, the handle will return to the initial position under the action of the spring force, the initial position is the position where the inner side of the handle is close to the outer periphery of the lower joint, such as Figure 9 On the contrary, when the self-locking folding joint is in the open position, Figure 9 , directly turn the upper joint to the rear side, the intermediate state is as follows Figure 8 As shown, the slider will first retreat a short distance, and when the upper joint rotates to the vertical position, the spring pushes the adjusting rod to drive the slider to move forward to the position of the window 12, and finally achieves the following Figure 3 , Figure 4 and Figure 7 Locked state shown.

[0056] That is to say, during the entire process of the self-locking folding joint achieving the locked state, manual operation of the handle is not required, achieving a high degree of automation. In prior products or published literature, after the upper joint and the lower joint are rotated to achieve buckling, it is necessary to manually operate the handle at a large angle again to achieve locking; in the prior art, an eccentric locking mechanism or a buckling locking part generally needs to be separately installed on the handle. However, the self-locking folding joint of the present invention realizes automatic locking while simplifying parts, and is more secure and reliable, preventing potential safety hazards caused by the negligence of a small number of cyclists resulting in the self-locking folding joint not being locked. Of course, in industry standard specifications, some countries require that the handle must have a safety anti-loosening lock, which is not shown in the embodiments of the present invention, but can be additionally provided separately.

[0057] As Figure 14 , 15 Shown in

[0058] As Figure 16 , 17The third embodiment of the present invention is shown in the figure. The difference from the first embodiment is that the locking mechanism is different. The other components are the same and will not be described again. The locking mechanism of this embodiment includes a handle 4, an adjusting rod 5 and a slider 6. The handle 4 is threadedly connected to the tail end of the adjusting rod 5. A nut 56 is sleeved on the adjusting rod 5. The rear side of the nut abuts against the front side of the handle, and the front side of the nut abuts against the outer side of the rear part of the lower joint. The middle part of the adjusting rod has a surrounding boss 51, and the boss 51 abuts against the inner wall of the rear part of the lower joint. The front end of the adjusting rod 5 is threadedly connected to the slider 6, and the two can rotate with each other. When the handle is turned, the slider 6 retreats, and the upper joint can be rotated to the front side to realize the open state of the self-locking folding joint. On the contrary, when closing the self-locking folding joint, the handle is turned in the opposite direction again, and the slider moves forward, so that the slider reaches the position of the window 12 formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint, and finally realizes the locked state. Although this locking mechanism does not have the function of automatic locking, its structure is simpler and more convenient to assemble.

[0059] like Figures 18 to 21 The fourth embodiment of the present invention is shown, which differs from the first embodiment in that the locking mechanism is different, and the remaining components are the same and will not be described in detail. The locking mechanism of this embodiment includes a handle 4, an adjusting rod 5 and a slider 6; wherein the handle 4 is a set of components, including a spring 43, a push rod 44, a rocker arm 45 and a pin 46; the handle 4 is threadedly fixedly connected to the tail end of the push rod 44, a spring 43 is sleeved on the push rod 44, the push rod 44 has a large end portion pressing against the front side of the rocker arm 45, and the pin 46 is passed through the through hole at the upper end of the rocker arm 45 and the through hole at the upper end of the plug 22; the front end of the adjusting rod 5 is threadedly fixedly connected to the slider 6, and the tail end of the adjusting rod 5 is sleeved in the hole 103 at the rear of the lower joint; the middle part of the adjusting rod is provided with a boss 51, and a spring 52 is sleeved on the adjusting rod 5, the front end of the spring abuts against the boss 51, and the rear end of the spring abuts against the inner wall of the rear part of the lower joint, and a pin 58 is provided on the side of the hole 103 at the rear part of the lower joint, and cooperates with the elongated groove 57 on the side of the adjusting rod 5 to limit the rotation of the adjusting rod 5. When the handle 4 is pressed, the push rod 44 pushes the rocker arm 45, and the rocker arm 45 then moves the boss 51 on the adjusting rod, thereby driving the slider 6 to retreat, and the upper joint can be rotated to the front side, realizing the open state of the self-locking folding joint; conversely, when closing the self-locking folding joint, the spring 52 pushes the adjusting rod 5 forward, so that the slider 6 reaches the position of the window 12 formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint, and the slider 6 moves forward under the action of the spring 52 to press the upper joint and the lower joint tightly, finally realizing the locked state.

[0060] The self-locking folding joint can be widely applied to handlebars and frames of folding bicycles, folding electric vehicles, folding scooters and other parts of the vehicles.

[0061] The terms "upper", "lower", "left", "right", "front", and "rear" appearing in the present invention are only for illustrative purposes. Among them, "upper" and "lower" can be interchanged, "left" and "right" can be interchanged, and "front" and "rear" can be interchanged.

[0062] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A self-locking folding joint, comprising a lower joint, an upper joint and a locking mechanism. Lugs are provided on the left and right sides of the upper joint, and a central axis passes through the lugs and the lower joint for hinge connection; it is characterized in that: A window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint. The slider in the locking mechanism is arranged in the window and is located inside the rotation direction of the upper joint and the lower joint. When locked, the lower edge of the front part of the upper joint is in contact with the upper surface of the slider, and the upper edge of the front part of the lower joint is in contact with the lower surface of the slider; the rear part of the lower joint abuts against the rear part of the upper joint; when unlocking, the locking mechanism drives the slider to move backward so that the slider exits the window. Grooves are provided on both the left and right sides of the lower joint, and the lugs in the upper joint are accommodated in the grooves; the back of the groove is located at the rear part of the lower joint and abuts against the rear side of the lug. The locking mechanism has a handle, an adjusting rod and a slider. The handle is arranged outside the joint. The adjusting rod includes an accessory transmission rod connected to its rear end. An opening is provided at the rear part of the lower joint. The tail end of the accessory transmission rod is hinged to the handle through the opening, and the front end of the adjusting rod is fixedly connected to the slider.

2. The self-locking folding joint according to claim 1, wherein: The rear part of the lower joint has an upper edge, the rear part of the upper joint has a lower edge, and the lower edge of the rear part of the upper joint abuts against the upper edge of the rear part of the lower joint.

3. The self-locking folding joint according to claim 1, wherein: The upper surface and the lower surface of the slider have an included angle.

4. The self-locking folding joint according to claim 1, characterized in that: The middle part of the adjusting rod has a surrounding boss, and a spring is sleeved on the adjusting rod. The front end of the spring abuts against the boss, and the rear end of the spring abuts against the inner wall of the rear part of the lower joint.

5. The self-locking folding joint according to claim 1, wherein: The lower joint has a hollow inner cavity, and a central shaft passes through the inner cavity; a hook spring is arranged in the inner cavity. The lower end of the hook spring is connected to the central shaft, and the upper end of the hook spring is connected to the adjusting rod.

6. The self-locking folding joint according to claim 1, wherein: The upper end inside of the upper joint is hollow, and a plug is arranged inside the upper end of the upper joint. The lower side of the plug is an inward concave arc surface.

7. The self-locking folding joint according to any one of claims 1 to 6, characterized in that: A slit is provided at the rear part of the lower joint, and a convex rib is provided on the front side of the lower part of the handle. The convex rib extends into the slit, and a first hinge shaft passes through the lower joint and the convex rib for connection; a convex column is provided on the front side of the middle part of the handle and is hinged to the tail end of the adjusting rod through a second hinge shaft; the axis lines of the first hinge shaft and the second hinge shaft are respectively parallel to the axis line of the central shaft.

8. A self-locking folding joint, comprising a lower joint, an upper joint and a locking mechanism, wherein lugs are respectively arranged on the left and right sides of the upper joint, and a central shaft passes through the lugs and the lower joint for hinged connection; characterized in that: A window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint. The slider in the locking mechanism is arranged in the window and is located inside the rotation direction of the upper joint and the lower joint. When locked, the lower edge of the front part of the upper joint is in contact with the upper surface of the slider, and the upper edge of the front part of the lower joint is in contact with the lower surface of the slider; the rear part of the lower joint abuts against the rear part of the upper joint; when unlocking, the locking mechanism drives the slider to move backward so that the slider exits the window. Grooves are provided on both the left and right sides of the lower joint, and the lugs in the upper joint are accommodated in the grooves; the back of the groove is located at the rear part of the lower joint and abuts against the rear side of the lug. The locking mechanism includes a handle and an adjusting rod. An opening is provided at the rear part of the lower joint. The tail end of the adjusting rod is fixedly connected to the handle through the opening, and the front end of the adjusting rod is fixedly connected to the slider. The upper surface and the lower surface of the slider have an included angle.

9. The self-locking folding joint according to claim 8, characterized in that: The rear part of the lower joint has an upper edge, the rear part of the upper joint has a lower edge, and the lower edge of the rear part of the upper joint abuts against the upper edge of the rear part of the lower joint.

10. The self-locking folding joint according to claim 8, wherein: The middle part of the adjusting rod has a surrounding boss, and a spring is sleeved on the adjusting rod. The front end of the spring abuts against the boss, and the rear end of the spring abuts against the inner wall of the rear part of the lower joint.

11. The self-locking folding joint according to claim 8, wherein: The lower joint has a hollow inner cavity, and a central shaft passes through the inner cavity; a hook spring is arranged in the inner cavity. The lower end of the hook spring is connected to the central shaft, and the upper end of the hook spring is connected to the adjusting rod.

12. The self-locking folding joint according to claim 8, wherein: The upper end of the upper joint is hollow inside, and a plug is arranged inside the upper end of the upper joint. The lower side of the plug is an inwardly concave arc surface.

13. A self-locking folding joint, comprising a lower joint, an upper joint and a locking mechanism. Lugs are respectively arranged on the left and right sides of the upper joint, and a central shaft passes through the lugs and the lower joint for hinged connection. It is characterized in that: A window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint. The slider in the locking mechanism is arranged in the window and is located inside the rotation direction of the upper joint and the lower joint. When locked, the lower edge of the front part of the upper joint fits with the upper surface of the slider, and the upper edge of the front part of the lower joint fits with the lower surface of the slider; the rear part of the lower joint abuts against the rear part of the upper joint; when unlocking, the locking mechanism drives the slider to move backward so that the slider exits the window. Grooves are respectively arranged on the left and right sides of the lower joint, and the lugs in the upper joint are accommodated in the grooves; the back surface of the groove is located at the rear part of the lower joint and abuts against the rear side surface of the lug. The locking mechanism includes a handle and an adjusting rod. The handle is connected to the tail end of the adjusting rod. A nut is sleeved on the adjusting rod. The rear side of the nut abuts against the front side of the handle, and the front side of the nut abuts against the outer side of the rear part of the lower joint; the front end of the adjusting rod is threadedly connected to the slider; a surrounding boss is provided in the middle of the adjusting rod, and the boss abuts against the inner wall of the rear part of the lower joint.

14. The self-locking folding joint according to claim 13, wherein: The rear part of the lower joint has an upper edge, and the rear part of the upper joint has a lower edge. The lower edge of the rear part of the upper joint abuts against the upper edge of the rear part of the lower joint.

15. The self-locking folding joint according to claim 13, wherein: An included angle exists between the upper surface and the lower surface of the slider.

16. A self-locking folding joint, comprising a lower joint, an upper joint and a locking mechanism. Lugs are provided on the left and right sides of the upper joint, and a central axis passes through the lugs and the lower joint for hinged connection; characterized in that: A window is formed between the upper edge of the front part of the lower joint and the lower edge of the front part of the upper joint. The slider in the locking mechanism is arranged in the window and is located inside the rotation direction of the upper joint and the lower joint. When locked, the lower edge of the front part of the upper joint fits with the upper surface of the slider, and the upper edge of the front part of the lower joint fits with the lower surface of the slider; the rear part of the lower joint abuts against the rear part of the upper joint; when unlocking, the locking mechanism drives the slider to move backward so that the slider exits the window. Grooves are respectively arranged on the left and right sides of the lower joint, and the lugs in the upper joint are accommodated in the grooves; the back surface of the groove is located at the rear part of the lower joint and abuts against the rear side surface of the lug. The locking mechanism includes a handle and an adjusting rod. The handle is a set of components, including a first spring, a push rod, a rocker arm and a pin shaft; the handle is fixedly connected to the tail end of the push rod. The first spring is sleeved on the push rod. One big-end end of the push rod presses against the front side of the rocker arm. The upper end of the upper joint is hollow inside, and a plug is arranged inside the upper end of the upper joint. The pin shaft passes through the through hole at the upper end of the rocker arm and the through hole at the upper end of the plug; the front end of the adjusting rod is fixedly connected to the slider, and the tail end of the adjusting rod is sleeved in the hole at the rear part of the lower joint; a pin is arranged on the side of the hole at the rear part of the lower joint and is matched with the long groove on the side surface of the adjusting rod.

17. The self-locking folding joint according to claim 16, wherein: The rear part of the lower joint has an upper edge, and the rear part of the upper joint has a lower edge. The lower edge of the rear part of the upper joint abuts against the upper edge of the rear part of the lower joint.

18. The self-locking folding joint according to claim 16, wherein: An included angle exists between the upper surface and the lower surface of the slider.

19. The self-locking folding joint according to claim 16, wherein: A surrounding boss is provided in the middle of the adjusting rod. A spring is sleeved on the adjusting rod. The front end of the spring abuts against the boss, and the rear end of the spring abuts against the inner wall of the rear part of the lower joint.

20. The self-locking folding joint according to claim 16, wherein: The lower joint has a hollow inner cavity, and a central shaft passes through the inner cavity; a hook spring is arranged in the inner cavity. The lower end of the hook spring is connected to the central shaft, and the upper end of the hook spring is connected to the adjusting rod.

21. The self-locking folding joint according to claim 16, characterized in that: The lower side of the plug is an inwardly concave arc surface.

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