Spherical joint mechanism with tension locking function

Abstract

The invention provides a spherical joint mechanism with a tension locking function. The spherical joint mechanism comprises an upper hemispherical shell, a lower hemispherical shell and a ball head assembly. The upper hemispherical shell is provided with a smooth surface and a resistance increasing surface, a through hole is formed in the middle of the lower hemispherical shell, and the upper hemispherical shell and the lower hemispherical shell are connected through a flange to form a spherical cavity. The ball head assembly is located in the ball cavity and comprises a ball head, a plurality of friction plate assemblies, a friction plate reset assembly, a pull rod assembly, a pull rod reset compression spring and a limiting threaded sleeve, and the pull rod assembly penetrates through a lower end hole of the ball cavity. When the pull rod is not pulled, the friction plate assembly does not make contact with the resistance increasing surface of the upper hemispherical shell, and the spherical joint can freely rotate within three degrees of freedom within a certain range. When the pull rod assembly is pulled, the pull rod assembly slides downwards in the ball head slideway to push the friction plate assembly to be tightly pressed with the upper semispherical shell, the friction resistance moment prevents the ball joint from freely rotating, and locking is achieved. And after the tension applied to the pull rod is unloaded, the spherical joint is driven by the pull rod reset pressure spring and the friction plate reset assembly to recover the free rotation state.

Description

Technical Field

[0001] The invention relates to a spherical joint mechanism and belongs to the field of engineering machinery and automation. Background Art

[0002] When a robotic arm or crane lifts and transfers items, there is a risk of swinging and twisting when using flexible structures such as slings and wire ropes as lifting tools. Using rigid lifting tools such as pull rods can improve the risk of swinging and twisting. The posture of mobile robots and cranes may be tilted. The pull rod lifting tool can keep the direction of gravity coincident by adaptively tilting the angle to avoid large bending moments of the pull rod due to misalignment with the direction of gravity, which increases the risk of the pull rod breaking. The three-degree-of-freedom freely rotating spherical joint connection allows the pull rod lifting tool to adapt to the direction of gravity, but the freely rotating ball joint increases the risk of the lifting target undergoing a single pendulum motion around the ball joint. Summary of the invention

[0003] The technical problem to be solved by the present invention is: the present invention provides a spherical joint mechanism with a tension locking function, aiming to provide a connection mechanism for the sling and the end of a mechanical arm or a crane and a pull rod that is adaptive to the crane posture inclination and prevents shaking.

[0004] The technical solution adopted by the present invention is: a spherical joint mechanism with tension locking function, comprising: an upper hemispherical shell, a lower hemispherical shell, and a ball head assembly; the upper hemispherical shell and the lower hemispherical shell are connected to form a spherical joint ball cavity, and the ball head assembly is located in the spherical joint ball cavity;

[0005] The ball head assembly includes a ball head, several friction plate assemblies and friction plate reset assemblies, a pull rod assembly, a pull rod reset compression spring, and a limit screw sleeve; the ball head is provided with a stepped through hole along the central axis of the ball head, the pull rod assembly is installed in the stepped through hole, and the pull rod reset compression spring is installed on the pull rod assembly; the limit screw sleeve is installed at one end of the pull rod assembly, and the pull rod assembly is installed on the ball head; several friction plate assemblies and corresponding friction plate reset assemblies are installed at one end of the ball head around the central axis of the ball head, and the central axes of the friction plate assembly accommodating through hole on the ball head and the friction plate reset assembly accommodating through hole are perpendicular to each other; the friction plate assembly contacts the pull rod assembly, slides in the friction plate assembly accommodating through hole on the ball head, and is driven by the pull rod assembly and the friction plate reset assembly to realize reciprocating motion, thereby realizing locking and unlocking between the ball head and the ball cavity of the spherical joint.

[0006] Furthermore, the middle area of ​​the inner surface of the upper hemispherical shell is a smooth spherical surface, and the periphery of the smooth spherical surface is a non-smooth drag-increasing surface; the outer envelope surface of the ball head is a smooth spherical surface, one end of the stepped through hole is a threaded hole for mounting a limit screw sleeve, and a plurality of beveled planes a are evenly distributed around the central axis of the ball head at the port at the other end of the stepped through hole, and a friction plate reset assembly accommodating through hole is provided on each beveled plane a, and a plurality of beveled planes b are evenly distributed around the central axis of the ball head at one end of the ball head surface where the beveled plane a is provided, and a friction plate assembly accommodating through hole is provided on each beveled plane b, and the friction plate assembly accommodating through holes correspond one-to-one to the friction plate reset assembly accommodating through holes, and the central axis of the friction plate assembly accommodating through hole is perpendicular to the central axis of the corresponding friction plate reset assembly accommodating through hole.

[0007] Furthermore, the friction plate assembly includes a friction plate top column, a spring, a friction plate and a connecting screw. The friction plate and the spring are installed on one end of the friction plate top column by means of the connecting screw, and the spring is located between the friction plate and the end of the friction plate top column; an annular groove is provided on the side wall of the friction plate top column, and the end in contact with the pull rod assembly is a spherical surface; the side surface of the friction plate is a cylindrical surface, the top surface is an arc surface with the same radius as the non-smooth drag-increasing surface of the upper hemispherical shell, the bottom surface is a plane, and a countersunk screw hole is opened in the center.

[0008] Furthermore, the friction plate reset assembly includes a nut, a reset spring, a sliding shoe, and a limiting ball, and the nut is installed on the ball head; the reset spring is located between the nut and the sliding shoe, and during the locking process of the spherical joint mechanism, the compression of the reset spring increases, and during the resetting process of the friction plate assembly, the compression decreases, providing thrust for the limiting ball; the limiting ball is located between the sliding shoe and the friction plate top column; the resetting of the friction plate assembly means that the friction plate is separated from the contact surface of the upper hemisphere shell under the traction of the friction plate top rod, and the spherical joint returns to the unlocked state; during the locking process of the spherical joint mechanism, the inclined surface of the friction plate top rod pushes the limiting ball and the sliding shoe to slide and compress the reset spring; during the unlocking process of the spherical joint mechanism, the limiting ball pushes the friction plate top rod to make the friction plate top rod move in the opposite direction, the friction plate is separated from the upper hemisphere shell, and the limiting ball enters the annular groove on the side wall of the friction plate top column.

[0009] Furthermore, the pull rod assembly includes a sleeve, an inner ball top column, a ball pair pre-tightening spring, and a pull rod; the inner ball top column is installed in the center hole of the sleeve, the inner ball top column can move along the center hole of the sleeve, and the sleeve limits the inner ball top column axially; the sleeve is installed at one end of the pull rod where a cavity is provided, and the ball pair pre-tightening spring is located in the cavity at the end of the pull rod, with both ends respectively pressed on the inner ball top column and the pull rod to provide pre-pressure for keeping the ball head in the center position.

[0010] Furthermore, the pull rod is a multi-section stepped shaft, one end of which is provided with a step hole for installing a screw sleeve, an inner ball top column and a ball pair preload spring, and from one end to the other end of the pull rod, it includes a locking section, an action section, an unlocking section, a guide section, and an external interface section in sequence; the locking section is a cylindrical structure, the action section is a truncated cone structure, and the unlocking section is a cylindrical structure; the large end of the action section is connected to the locking section, and the small end is connected to the unlocking section; the guide section is a large-diameter cylinder with a diameter larger than the locking section; the external interface section is a cylinder with a guide protrusion and an external connecting thread, and the length of the guide protrusion is greater than the sum of the lengths of the locking section, the action section, and the unlocking section.

[0011] Furthermore, the inner ball top column is a stepped shaft, the small diameter shaft section passes through the screw sleeve and points to the inner surface of the upper hemispherical shell, and the large diameter shaft section has a diameter larger than the center hole of the screw sleeve and is pressed tightly on the ball pair preload spring.

[0012] Furthermore, the limiting screw sleeve is provided with a stepped hole along the central axis, and an outer surface of the limiting screw sleeve is provided with an external thread; the large end of the stepped hole is a round hole, and the small end is a through hole with a guide boss, and the guide boss is evenly distributed around the small end.

[0013] Furthermore, when the ball joint mechanism is in the unlocked state, the end face of the guide section of the pull rod is pressed against the step surface of the stepped through hole of the ball head under the action of the pull rod reset compression spring, the inner ball top column is supported on the smooth surface inside the upper hemispherical shell to keep the ball head located in the center position of the spherical joint ball cavity, and the friction plate top column maintains a gap with the inner surface of the upper hemispherical shell under the action of the limiting ball and the reset compression spring; the pull rod and the ball head can rotate in the spherical joint ball cavity, and the rotation angle is determined by the size of the spherical center hole on the lower hemispherical shell through which the pull rod passes.

[0014] Furthermore, the locking process of the ball joint mechanism is as follows: when the pull rod is subjected to axial tension, it slides in the direction of the tension, and the action section of the pull rod pushes the friction plate top column to move radially outward, compressing the spring plate and the return spring, and pushing the friction plate to press against the non-smooth resistance-increasing surface of the inner surface of the upper hemispherical shell; when the friction plate top column contacts the locking section, the locking is completed;

[0015] The process of the ball joint mechanism changing from a locked state to an unlocked state is as follows: after the tension on the pull rod is reduced, the pull rod reset spring pushes the pull rod to move toward the inside of the spherical joint ball cavity, and the reset spring pushes the friction plate top column to move in the opposite direction, the friction plate separates from the inner surface of the upper hemisphere shell, and the pull rod returns to a free rotation state.

[0016] The advantages of the present invention compared with the prior art are:

[0017] The ball joint mechanism of the present invention has a tension locking function and can be applied to the end of a sling and a mechanical arm or a crane and a pull rod. The pull rod lifting using the ball joint mechanism of the present invention can adapt to the tension angle by rotating the three-degree-of-freedom rotation to keep it coincident with the tension direction, thereby avoiding damage to the pull rod due to a large bending moment; the pull rod is locked after being subjected to tension, thereby avoiding a single pendulum motion around the ball joint and reducing the risk of shaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An exploded view of the spherical joint mechanism with tension locking function according to the present invention;

[0019] Figure 2 An exploded view of the ball head assembly of the spherical joint mechanism with tension locking function according to the present invention;

[0020] Figure 3 It is a cross-sectional view of the spherical joint mechanism with tension locking function of the present invention in a state without tension;

[0021] Figure 4 It is a cross-sectional view of the spherical joint mechanism with tension locking function of the present invention in a state where it is not subjected to tension and rotated at a certain angle;

[0022] Figure 5 It is a cross-sectional view of the locked state of the spherical joint mechanism with tension locking function according to the present invention;

[0023] Figure 6 This is the structural diagram of the limiting screw sleeve.

[0024] In the figure, 1-lower hemispherical shell, 2-ball head, 3-friction plate top column, 4-spring, 5-friction plate, 6-connecting screw, 7-upper hemispherical shell, 8-gasket, 9-bolt, 10-locating pin, 11-nut, 12-reset spring, 13-slipper, 14-limiting ball, 15-screw, 16-inner ball top column, 17-ball pair preload spring, 18-pull rod, 19-pull rod reset spring, 20-limiting screw, 21-nut. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific examples. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0026] Reference Figure 1-Figure 5 As shown, a spherical joint mechanism with tension locking function includes: a lower hemispherical shell 1, an upper hemispherical shell 7, and a ball head assembly.

[0027] The inner surface of the lower hemispherical shell 1 is a smooth hemispherical surface, a connecting flange structure is provided on the edge, and a through hole is provided in the middle.

[0028] The inner surface of the upper hemispherical shell 7 is a hemispherical surface, and a connecting flange structure is provided on the edge. The middle area of ​​the inner hemispherical surface is a smooth surface, and the outer periphery is a non-smooth resistance-increasing surface.

[0029] The lower hemispherical shell 1 and the upper hemispherical shell 7 are connected by bolts 9 and nuts 21 and positioned by two positioning pins 10 to form a ball cavity of the spherical joint.

[0030] The ball head assembly is located in the ball cavity of the spherical joint, and includes a ball head 2, four friction plate assemblies, four friction plate reset assemblies, a pull rod assembly, a pull rod reset compression spring 19, and a limiting screw sleeve 20.

[0031] The outer envelope surface of the ball head 2 is a smooth spherical surface, and there are multiple cutting planes at the lower end and the upper side to facilitate hole processing and threaded connection; there is a stepped through hole in the center, and the lower end of the through hole is a threaded hole, which is connected to the limiting screw sleeve 20. A plurality of friction plate assembly accommodating circular holes are radially evenly distributed at a certain elevation angle above the periphery, and the outer ends of the accommodating circular holes have internal threads. A friction plate reset assembly accommodating circular hole is provided in a direction perpendicular to the friction plate assembly accommodating circular hole, and the outer ends of the accommodating circular hole have internal threads. One end of the stepped through hole of the ball head 2 is a threaded hole for mounting a limiting screw sleeve, and a plurality of beveled planes a22 are evenly distributed around the central axis of the ball head at the port at the other end of the stepped through hole, and a friction plate reset component accommodating through hole is provided on each beveled plane a22. A plurality of beveled planes b23 are evenly distributed around the central axis of the ball head on one end of the ball head surface where the beveled plane a22 is provided, and a friction plate component accommodating through hole is provided on each beveled plane b23, and the friction plate component accommodating through holes correspond to the friction plate reset component accommodating through holes one by one, and the central axis of the friction plate component accommodating through hole is perpendicular to the central axis of the corresponding friction plate reset component accommodating through hole.

[0032] The friction plate assembly is installed in the radial inner cavity of the ball head, including a friction plate top column 3, a spring 4, and a friction plate 5, which are connected in series by a connecting screw 6. The friction plate 5 and the spring 4 are installed at one end of the friction plate top column 3 by the connecting screw 6. The spring 4 is located between the friction plate 5 and the end of the friction plate top column 3, and can slide in the radial cavity of the ball head 2. The friction plate 5 can be pressed against the inner surface of the ball cavity under the push of the pull rod assembly. The spring 4 is to ensure that even if there is mechanical transmission error and wear, sufficient positive pressure is maintained between the friction plate 5 and the inner surface of the upper hemispherical shell 7.

[0033] The friction plate top column 3 is a stepped cylindrical shape, with a threaded hole and a stepped shaft at one end, connected to the friction plate 5 and the spring plate 4, with a V-shaped cross-section ring groove in the middle, and a spherical bottom surface at the other end, which contacts the pull rod assembly and can slide in the cavity of the ball head 2, and is driven by the pull rod 18 and the friction plate reset assembly to achieve reciprocating motion.

[0034] The spring leaf 4 is compressed during the locking process of the ball joint, which can prevent the positive pressure and friction force between the friction plate 5 and the inner surface of the upper hemispherical shell 7 from decreasing too much due to transmission error and wear.

[0035] The side surface of the friction plate 5 is a cylindrical surface, the top surface is a partial spherical surface with the same radius as the inner spherical surface of the upper hemispherical shell 7, and the bottom surface is a plane with a countersunk screw hole in the center.

[0036] The friction plate reset assembly mainly includes a nut 11, a reset compression spring 12, a sliding shoe 13, and a limiting ball 14, which are serially arranged in the ball head 2 cavity and perpendicular to the friction plate assembly. The main function is to provide driving force for resetting the friction plate assembly.

[0037] The so-called resetting of the friction plate assembly means that the friction plate 5 is separated from the contact surface of the upper hemispherical shell 7 under the traction of the friction plate push rod 3, and the spherical joint returns to the unlocked state.

[0038] The nut 11 is threadedly connected to the ball head 2 , and mainly provides axial limit and initial compression adjustment for the return compression spring 12 .

[0039] The return compression spring 12 is located between the nut 11 and the sliding shoe 13 . The compression amount of the return compression spring 12 increases during the locking process, and decreases during the resetting process of the friction plate assembly, thereby providing thrust for the limiting ball 14 .

[0040] The side surface of the sliding shoe 13 is a cylindrical surface, the bottom surface of one end is a plane, and the other end is a ball socket. It is located between the reset compression spring 12 and the limiting ball 14, and can slide in the reset component cavity of the ball head 2. It mainly transmits the pressure between the reset compression spring 12 and the limiting ball 14 to protect the surface of the limiting ball 14.

[0041] The limiting ball 14 is a spherical roller, located between the ball socket of the sliding shoe 13 and the friction plate push rod 3, and pressed against the inclined surface of the friction plate push rod 3. During the locking process, the inclined surface of the friction plate push rod 3 pushes the limiting ball 14 and the sliding shoe 13 to slide and compress the return compression spring 12; during the unlocking process, the limiting ball 14 pushes the friction plate push rod 3 to move in the opposite direction, and the friction plate 5 is separated from the upper hemispherical shell 7.

[0042] The pull rod assembly is located in the stepped hole passing through the symmetry axis of the ball head 2 , and comprises a screw sleeve 15 , an inner ball top column 16 , a ball pair preload spring 17 , and a pull rod 18 , and can slide in the stepped hole of the ball head 2 .

[0043] The screw sleeve 15 has a through hole inside, and the external thread is connected to the pull rod 18. The size of the through hole matches the small diameter shaft of the inner ball top column 16 and is smaller than the large diameter shaft section of the inner ball top column 16, providing guidance and axial limitation for the inner ball top column 16.

[0044] The inner ball top column 16 is a two-section stepped shaft, the small diameter shaft section passes through the screw sleeve 15 and points to the inner surface of the upper hemispherical shell 7, and the large diameter shaft section has a diameter larger than the through hole of the screw sleeve 15 and is pressed against the ball pair preload spring 17.

[0045] The ball pair preload spring 17 is located in the cavity of the pull rod 18, and its two ends are respectively pressed on the inner ball top column 16 and the pull rod 18 to provide preload to keep the ball head 2 in the center position and avoid scratching between the ball head 2 and the resistance-increasing surface of the upper hemispherical shell 7.

[0046] The main body of the pull rod 18 is a multi-section stepped shaft, with a small hole and a threaded hole at one end for installing the auxiliary preload spring 17, the inner ball top column 16 and the screw sleeve 15, and the other end is sequentially provided with a locking section, an action section, an unlocking section, a guide section, and an external interface section. The locking section is a section of a cylinder, which is mainly used to maintain the position of the friction plate top column 3 when locking, that is, to maintain the locking state. The action section is an inverted truncated cone structure with a large upper part and a small lower part, and its main function is to push the friction plate top column 3 to move and lock the joint. The unlocking section is a small-diameter cylinder. When the spherical surface of the friction plate top column 3 contacts this section, the ball joint is in an unlocked state. The guide section is a large-diameter cylinder, which mainly guides the axial sliding of the pull rod 18 and transmits the load of the pull rod 18 to the ball head 2 through the end face. The external interface section is a cylinder with a guide protrusion and an external connection thread, and the length of the guide protrusion is greater than the sum of the lengths of the locking section, the action section, and the unlocking section.

[0047] The pull rod reset compression spring 19 is sleeved on the pull rod 18 and is located between the limiting screw sleeve 20 and the guide section of the pull rod 18 to provide a reset elastic force for the pull rod 18 .

[0048] The limiting screw sleeve 20 has a stepped hole in the middle and an external thread on the outer surface, which is threadedly connected to the ball head 2. The large end of the middle stepped hole is a cylindrical hole, and the small end is a through hole with a guide boss. The guide bosses 24 are evenly distributed around the small end. Figure 6 As shown, the return compression spring 19 is mainly compressed and the load of the pull rod 18 is transmitted to the ball head 2.

[0049] The ball joint is in the unlocked state. Figure 3 and Figure 4 As shown, the upper end surface of the guide section of the pull rod 18 is pressed against the limiting end surface of the ball head 2 under the action of the pull rod reset compression spring 19, the inner ball top column 16 is supported on the smooth inner surface of the upper hemispherical shell 7 to keep the ball head 2 located at the center of the ball cavity, and the friction plate top column 3 maintains a certain gap with the inner surface of the upper hemispherical shell 7 under the action of the limiting ball 14 and the reset compression spring 12. The pull rod 18 and the ball head 2 can rotate freely within a certain range in the ball cavity, and the rotation angle is determined by the size of the through hole of the lower hemispherical shell 1 through which the pull rod 18 passes.

[0050] The locking process of the ball joint can be described as follows: when the pull rod 18 is subjected to a large axial tensile force, it slides along the tensile force direction, and the action section of the pull rod 18 pushes the friction plate top column 3 to move radially outward, compressing the spring plate 4 and the return compression spring 12, and pushing the friction plate 5 to press against the inner surface of the upper hemispherical shell 7, as shown in FIG. Figure 5 When the friction plate top column 3 contacts the locking section, the locking is completed. In the locked state, the friction between the friction plate 5 and the resistance-increasing inner surface of the upper hemispherical shell 7 prevents the pull rod and the ball head from swinging relative to the outer spherical shell.

[0051] The process of the ball joint from a locked state to an unlocked state can be described as: after the tension on the pull rod 18 is reduced, the pull rod reset spring 19 pushes the pull rod 18 to move upward (toward the inside of the spherical joint ball cavity), and the reset spring 12 of the friction plate reset assembly pushes the friction plate top column 3 to move in the opposite direction, the friction plate 5 is separated from the inner surface of the upper hemispherical shell 7, and the pull rod 18 returns to a free rotation state.

[0052] The present invention locks the pull rod when it is pulled and restores free swinging after the pulling force is removed, thereby enhancing the posture adaptability of the pull rod and preventing the pull rod from being subjected to excessive bending moment.

[0053] The above specific embodiments are merely explanations of the present application, and are not limitations of the present application. Those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. As long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A spherical joint mechanism with tension locking function, characterized in that: include: An upper hemispherical shell (7), a lower hemispherical shell (1), and a ball head assembly; the upper hemispherical shell (7) and the lower hemispherical shell (1) are connected to form a spherical joint cavity, and the ball head assembly is located in the spherical joint cavity; The ball head assembly comprises a ball head (2), a plurality of friction plate assemblies and friction plate reset assemblies, a tie rod assembly, a tie rod reset compression spring (19), and a limiting screw sleeve (20); the ball head (2) is provided with a stepped through hole along the central axis of the ball head, the tie rod assembly is installed in the stepped through hole, and the tie rod reset compression spring (19) is installed on the tie rod assembly; the limiting screw sleeve (20) is installed at one end of the tie rod assembly, and the tie rod assembly is installed on the ball head (2); a plurality of friction plate assemblies and corresponding friction plate reset assemblies are installed at one end of the ball head (2) around the central axis of the ball head, and the central axes of the friction plate assembly accommodating through hole on the ball head (2) and the friction plate reset assembly accommodating through hole are perpendicular to each other; the friction plate assembly contacts the tie rod assembly, slides in the friction plate assembly accommodating through hole on the ball head (2), and is driven by the tie rod assembly and the friction plate reset assembly to realize reciprocating motion, thereby realizing locking and unlocking between the ball head (2) and the ball cavity of the spherical joint.

2. A spherical joint mechanism with tension locking function as claimed in claim 1, characterized in that: The middle area of ​​the inner surface of the upper hemispherical shell (7) is a smooth spherical surface, and the outer periphery of the smooth spherical surface is a non-smooth resistance-increasing surface; the outer envelope surface of the ball head (2) is a smooth spherical surface, one end of the stepped through hole is a threaded hole for mounting a limit screw sleeve, and a port at the other end of the stepped through hole is evenly distributed with a plurality of beveled planes a around the central axis of the ball head, each beveled plane a is provided with a friction plate reset component accommodating through hole, and a plurality of beveled planes b are evenly distributed around the central axis of the ball head at one end of the ball head surface provided with the beveled plane a, each beveled plane b is provided with a friction plate component accommodating through hole, the friction plate component accommodating through holes correspond to the friction plate reset component accommodating through holes one by one, and the central axis of the friction plate component accommodating through hole is perpendicular to the central axis of the corresponding friction plate reset component accommodating through hole.

3. A spherical joint mechanism with tension locking function as claimed in claim 2, characterized in that: The friction plate assembly comprises a friction plate top column (3), a spring plate (4), a friction plate (5) and a connecting screw (6), wherein the friction plate (5) and the spring plate (4) are mounted on one end of the friction plate top column (3) via the connecting screw (6), and the spring plate (4) is located between the friction plate (5) and the end of the friction plate top column (3); an annular groove is provided on the side wall of the friction plate top column (3), and the end in contact with the pull rod assembly is a spherical surface; the side surface of the friction plate (5) is a cylindrical surface, the top surface is an arc surface with the same radius as the non-smooth resistance-increasing surface of the upper hemispherical shell (7), and the bottom surface is a plane with a countersunk screw hole in the center.

4. A spherical joint mechanism with tension locking function as claimed in claim 3, characterized in that: The friction plate reset assembly comprises a nut (11), a reset spring (12), a sliding shoe (13), and a stop ball (14). The nut (11) is mounted on the ball head (2). The reset spring (12) is located between the nut (11) and the sliding shoe (13). During the locking process of the spherical joint mechanism, the compression amount of the reset spring (12) increases, and during the reset process of the friction plate assembly, the compression amount decreases, thereby providing thrust for the stop ball (14). The stop ball (14) is located between the sliding shoe (13) and the friction plate top column (3). The reset of the friction plate assembly refers to the friction plate ( 5) under the traction of the friction plate push rod (3), the contact surface of the upper hemispherical shell (7) is separated, and the spherical joint returns to the unlocked state; during the locking process of the spherical joint mechanism, the inclined surface of the friction plate push rod (3) pushes the limiting ball (14) and the sliding shoe (13) to slide and compress the return spring (12); during the unlocking process of the spherical joint mechanism, the limiting ball (14) pushes the friction plate push rod (3) to make the friction plate push rod (3) move in the opposite direction, the friction plate (5) is separated from the upper hemispherical shell (7), and the limiting ball (14) enters the annular groove on the side wall of the friction plate push rod (3).

5. A spherical joint mechanism with tension locking function as claimed in claim 4, characterized in that: The pull rod assembly comprises a screw sleeve (15), an inner ball top column (16), a ball pair preload spring (17), and a pull rod (18); the inner ball top column (16) is installed in the center hole of the screw sleeve (15), the inner ball top column (16) can move along the center hole of the screw sleeve (15), and the screw sleeve (15) axially limits the inner ball top column (16); the screw sleeve (15) is installed at one end of the pull rod (18) provided with a cavity, and the ball pair preload spring (17) is located in the cavity at the end of the pull rod (18), and the two ends are respectively pressed on the inner ball top column (16) and the pull rod (18) to provide preload for keeping the ball head (2) in the center position.

6. A spherical joint mechanism with tension locking function as claimed in claim 5, characterized in that: The pull rod (18) is a multi-section stepped shaft, one end of which is provided with a stepped hole for installing a screw sleeve (15), an inner ball top column (16) and a ball pair preload spring (17), and includes a locking section, an action section, an unlocking section, a guide section, and an external interface section from one end to the other end of the pull rod; the locking section is a cylindrical structure, the action section is a truncated cone structure, and the unlocking section is a cylindrical structure; the large end of the action section is connected to the locking section, and the small end is connected to the unlocking section; the guide section is a large diameter cylinder, the diameter of which is larger than the locking section; the external interface section is a cylinder with a guide protrusion and an external connection thread, and the length of the guide protrusion is larger than the sum of the lengths of the locking section, the action section, and the unlocking section.

7. A spherical joint mechanism with tension locking function as claimed in claim 6, characterized in that: The inner ball top column (16) is a stepped shaft, the small diameter shaft section passes through the screw sleeve (15) and points to the inner surface of the upper hemispherical shell (7), and the large diameter shaft section has a diameter larger than the center hole of the screw sleeve (15) and is pressed against the ball pair preload spring (17).

8. A spherical joint mechanism with tension locking function as claimed in claim 7, characterized in that: The limiting screw sleeve (20) is provided with a stepped hole along the central axis, and an external thread is provided on the outer surface of the limiting screw sleeve; the large end of the stepped hole is a round hole, and the small end is a through hole with a guide boss (24), and the guide boss (24) is evenly distributed around the small end.

9. A spherical joint mechanism with tension locking function as claimed in claim 8, characterized in that: When the ball joint mechanism is in the unlocked state, the end face of the guide section of the pull rod (18) is pressed against the step surface of the stepped through hole of the ball head (2) under the action of the pull rod reset compression spring (19), the inner ball top column (16) is supported on the smooth surface inside the upper hemispherical shell (7) to keep the ball head (2) located at the center position of the spherical joint ball cavity, and the friction plate top column (3) maintains a gap with the inner surface of the upper hemispherical shell (7) under the action of the limiting ball (14) and the reset compression spring (12); the pull rod (18) and the ball head (2) can rotate in the spherical joint ball cavity, and the rotation angle is determined by the size of the spherical center hole on the lower hemispherical shell (1) through which the pull rod (18) passes.

10. A spherical joint mechanism with tension locking function as claimed in claim 9, characterized in that: The locking process of the ball joint mechanism is as follows: when the pull rod (18) is subjected to axial tension, it slides in the direction of the tension, and the action section of the pull rod (18) pushes the friction plate top column (3) to move radially outward, compresses the spring plate (4) and the return spring (12), and pushes the friction plate (5) to be pressed against the non-smooth resistance-increasing surface of the inner surface of the upper hemispherical shell (7); when the friction plate top column (3) contacts the locking section, the locking is completed; The process of the ball joint mechanism changing from a locked state to an unlocked state is as follows: after the tension on the pull rod (18) is reduced, the pull rod reset spring (19) pushes the pull rod (18) to move toward the inside of the spherical joint cavity, the reset spring (12) pushes the friction plate top column (3) to move in the opposite direction, the friction plate (5) is separated from the inner surface of the upper hemispherical shell (7), and the pull rod (18) returns to a free rotation state.

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