Tripod support device with an operation synchronizing mechanism

Abstract

The tripod support device comprises a pivot seat unit (1) and three support rods (201), each support rod extending rotatably through the pivot seat unit (1) at the pivot portion and terminating at the upper and lower portions (22, 23). The upper portion forms a support surface (S) together when the support rods are in an unfolded state. A synchronization seat (31) is positioned between the support rods (201) and can move relative to the pivot seat unit (1) along a central axis (L), and has a hub (301) and three link protrusions (302). Three lower link bars (34) are rotatably connected to the link protrusions (302) of the support rods (201) and the lower pivot portions (24) to rotate the support rods (201) while the synchronization seat (31) moves. In the unfolded state, the longitudinal axis (X1) of each lower link bar (34) is offset from the central axis (L).

Description

Technology Field

[0001] The present disclosure relates to a tripod support device, and more specifically, to a tripod support device having an operation synchronization mechanism. Background Technology

[0002] A tripod support device is used for various purposes, such as supporting cameras, mobile phones, measuring equipment, etc., and a seat plate may be mounted on the tripod support device to allow sitting. The conventional tripod disclosed in CN220523748U includes a support seat, a central shank extending downward from the support seat, three pivot protrusions protruding radially from the support seat, three legs each having an upper end and pivotably connected to the pivot protrusions around a pivot axis extending tangentially from the support seat, a slide ring movably sleeved around the central shank, three link bars pivotably connected between the slide ring and the legs, and three pivot assemblies including two pivot heads each positioned on the legs corresponding to the slide ring and two pivot pins extending tangentially from the slide ring through a connecting rod corresponding to the pivot head.

[0003] When in use, the slide ring moves downward to extend the link bar, causing the lower ends of the legs to move away from the center shank simultaneously and touch the ground. Consequently, the legs extend or fold via the link bar depending on the movement of the slide ring. However, each leg has an upper end pivotably connected to a support seat, and the size of the support seat and its upper support surface is reduced to minimize the size of the tripod when folded, meaning the tripod can only support small equipment such as cameras and mobile phones. Additionally, while the slide ring moves and the legs extend simultaneously, the extension axis of the link bar faces the central axis of the center shank, which limits the rotational range of the link bar and hinders the smooth extension of the legs. The problem to be solved

[0004] Accordingly, the object of the present disclosure is to provide a tripod support device capable of mitigating at least one of the disadvantages of the prior art. means of solving the problem

[0005] According to the present disclosure, a tripod support device comprises a pivot seat unit, a support unit, and an operation synchronization mechanism. The pivot seat unit defines a central axis. The support unit is pivotally connected to the pivot seat unit and comprises at least three support rods, each support rod pivotally extending through the pivot seat unit to terminate at an upper and lower end opposite each other and is angularly spaced apart from each other about the central axis. Each support rod is pivotally coupled to the pivot seat unit and has a pivot portion interposed between the upper and lower end and a lower pivot portion interposed between the pivot portion and the lower end. The upper and lower end of the support rods are rotatable between a folded state (where the upper and lower end are close to the central axis) and an unfolded state (where the upper and lower end are far from the central axis). In the unfolded state, the upper end and lower end cooperate to form a support surface. The operation synchronization mechanism comprises a synchronization seat and three or more lower link bars. The synchronization seat is positioned between the support rods and is movable relative to the pivot seat unit along the central axis. The synchronization sheet has a hub and three or more link protrusions that protrude from the hub and are angularly spaced from each other about a central axis. Each lower link bar has a first link end rotatably connected to one of the link protrusions and a second link end located opposite the first link end along the longitudinal axis and rotatably connected to a lower rotating part on one of the support bars. While the synchronization sheet moves along the central axis relative to the pivot seat unit, the upper and lower ends of the support bars rotate between a folded state and an unfolded state by the lower link bars. In the unfolded state, the longitudinal axis of each lower link bar is offset from the central axis.

[0006] While the upper and lower parts of the support rod are rotating from a folded state to an unfolded state, the lower link bar rotates smoothly relative to the synchronization sheet and the support rod to facilitate the unfolding motion of the support rod. Brief explanation of the drawing

[0007] Other features and advantages of the present disclosure will become apparent from the following detailed description of embodiments with reference to the accompanying drawings. It should be noted that various features may not be drawn to scale. FIG. 1 is a perspective view showing a first embodiment of a tripod support device according to the present disclosure in an unfolded state. FIG. 2 is a perspective view showing the first embodiment in a folded state. FIG. 3 is a partial side view illustrating the first embodiment in an unfolded state. FIG. 4 is a partial side view showing the first embodiment in a folded state. Figure 5 is a cross-sectional view taken along the VV line of Figure 4. Figure 6 is a cross-sectional view taken along the line VI-VI of Figure 5. Figure 7 is a cross-sectional view taken along line VII-VII of Figure 6. Fig. 8 is a partial bottom view of Fig. 3. Figure 9 is a partial plan view of Figure 3. FIG. 10 is a partial side view illustrating the operation synchronization mechanism of the first embodiment. FIG. 11 is a cross-sectional view similar to FIG. 7 illustrating a modified form of the first embodiment. FIG. 12 is a cross-sectional view similar to FIG. 7 illustrating another modified form of the first embodiment. FIG. 13 is a perspective view showing a second embodiment of a tripod support device according to the present invention in an unfolded state. FIG. 14 is a partially exploded perspective view of the second embodiment. FIG. 15 is a partially exploded perspective view illustrating the synchronization sheet and three lower link bars of the operation synchronization mechanism of the second embodiment. FIGS. 16a, FIGS. 16b, and FIGS. 16c are schematic diagrams illustrating the unfolded operation of the second embodiment. FIG. 17 is a partial perspective view illustrating a third embodiment of a tripod support device according to the present disclosure in a folded state. FIG. 18 is a partially exploded perspective view of the third embodiment. FIG. 19 is a perspective view showing a fourth embodiment of a tripod support device according to the present invention in an unfolded state. FIG. 20 is a partially enlarged cross-sectional view of the fourth embodiment. FIG. 21 is a cross-sectional view showing the fourth embodiment in a folded state. Specific details for implementing the invention

[0008] Before describing the present disclosure in more detail, it should be noted that, where deemed appropriate, reference numbers or the end of reference numbers in the drawings are repeated to indicate corresponding or similar elements, and may optionally have similar characteristics.

[0009] For clarity of explanation, it should be noted that spatially relative terms such as “top,” “bottom,” “top,” “bottom,” “on top,” “from top,” “up,” “downward,” “upward,” etc., may be used throughout this disclosure while referring to the features illustrated in the drawings. Features may be arranged in different directions (e.g., rotated 90 degrees or in other directions), and terms used in this specification regarding spatial relatives may be interpreted accordingly.

[0010] Referring to FIGS. 1 and 2, a first embodiment of a tripod support device according to the present disclosure is configured to have a support plate (8) and a handle bar (9) mounted thereon. In this embodiment, the support plate (8) is a seat plate on which a user can sit, and the tripod support device of this embodiment is used as a foldable crutch chair. This embodiment can be used to support a camera, a mobile phone, a screen panel, etc.

[0011] Referring to FIGS. 3 and 4, the tripod support device includes a pivot seat unit (1), a support unit (2), and an operation synchronization mechanism (3).

[0012] Referring to FIGS. 4, 5 and 6, the pivot seat unit (1) is a short cylindrical shape that surrounds and defines the center of the central axis (L), and includes an upper surface (11), a lower surface (12) opposite to the upper surface (11) along the central axis (L), an outer perimeter wall (13) connected between the upper surface (11) and the lower surface (12), three extension holes (14) that extend through the upper and lower surfaces (11, 12) and are angularly spaced apart around the central axis (L), three pivot axes (17) that extend through the extension holes (14) and are angularly spaced apart around the central axis (L), and a receiving groove (16) that is recessed in the lower surface (12) to be open downward. Each extension hole (14) is defined by a hole surrounding a wall (15), which has a restraining wall section (151) near the central axis (L) and two end wall sections (152) connected to each of the two ends of the restraining wall section (151).

[0013] The support unit (2) is pivotally connected to the pivot seat unit (1) and includes three support rods (201), each of which is pivotally extended through a respective extension hole (14) and ends at an upper portion (22) and a lower portion (23) opposite each other, and is angularly spaced apart from each other about a central axis (L). Each support rod (201) has a pivot portion (21) interposed between the upper portion (22) and the lower portion (23) and rotatably engaged with the respective pivot axis (17), a lower pivot portion (24) interposed between the pivot portion (21) and the lower portion (23), and a rod surface (25) facing the restraining wall section (151) of the corresponding extension hole (14). The pivot portion (21) pivotally rotates along the corresponding restraining wall section (151) between the end wall sections (152). As illustrated in FIG. 9, the lower pivot portion (24) of each support rod (201) is mounted on the support rod (201) and has a pivot shaft (241) that extends radially and along a shaft axis (L3) perpendicular to the rod surface (25). Each pivot axle (17) extends along a rotation axis (L1) perpendicular to both the center axis (L) and the rod surface (25) (see FIG. 5). The upper portion (22) and lower portion (23) of the support rod (201) are rotatable between a folded state where the upper portion (22) and lower portion (23) are close to the center axis (L) and an unfolded state where the upper portion (22) and lower portion (23) are far from the center axis (L), and in the unfolded state, the upper portion (22) together forms a support surface (S) (see FIG. 3).

[0014] Referring to FIGS. 3, 6 and 7, the operation synchronization mechanism (3) is connected to a support rod (201) and includes a synchronization sheet (31), an extension stem (32), a biasing member (33), and three lower link bars (34).

[0015] Referring to FIGS. 7, 8 and 10, the synchronization sheet (31) is positioned downward from the pivot sheet unit (1) between the support rods (201) and has a hub (301) and three link protrusions (302) protruding from the hub (301) and angularly spaced from each other around the central axis (L). The hub (301) has a triangular cross-section and has a plurality of peripheral wall sections (311) angularly spaced from each other around the central axis (L), each facing the rod surface (25) of the support rod (201). Each link protrusion (302) has a link pin (312) that penetrates the corresponding lower link bar (34) along the pivot axis (L2) from the hub (301), and a stop (313) connected to the distal end of the link pin (312) and extending upward. Referring to FIG. 7, in this embodiment, the pivot axis (L2) of each link protrusion (302) is offset from the central axis (L). As shown in FIG. 11, in another modified embodiment, the hub (301) has a triangular cross-section, and the pivot axis (L2) of the link protrusion (302) intersects the central axis (L). Or, as shown in FIG. 12, the hub (301) has a rectangular cross-section, and the pivot axis (L2) of the link protrusion (302) intersects the central axis (L).

[0016] The lower end of the extension stem (32) is connected to the synchronization sheet (31) and extends along the central axis (L) toward the support plate (8), with the upper end connected to the support plate (8). Therefore, when the support plate (8) is pulled, the extension stem (32) moves along the central axis (L).

[0017] A biasing member (33) is compressibly wrapped in a sleeve around an extension stem (32), with its upper and lower ends in contact with the pivot seat unit (1) and the synchronization seat (31), respectively. The upper end of the biasing member (33) is received and fixed in a receiving groove (16) to provide a biasing action that presses the synchronization seat (31) downward from the pivot seat unit (1).

[0018] Referring to FIGS. 7, 8, and 9, each lower link bar (34) has a first link end (341) pivotally connected to a corresponding link protrusion (302) and a second link end (342) pivotally connected to a corresponding lower pivot part (24) located opposite the first link end (341) along the longitudinal axis (X1). Referring to FIG. 10, the first link end (341) of each lower link bar (34) has a first pivot hole (343) through which a corresponding link protrusion (302) passes. The first pivot hole (343) is in the form of an elongated hole having an enlarged rotational part (344) aligned with a link pin (312) and a hook part (345) located opposite the enlarged rotational part (344) along the longitudinal axis (X1) aligned with a stop part (313). Referring to FIG. 3, the second link end (342) of each lower link bar (34) has a second pivot hole (346).

[0019] While the synchronization sheet (31) moves along the central axis (L) relative to the pivot sheet unit (1), the upper portion (22) and lower portion (23) of the support bar (201) are rotated between a folded state and an unfolded state by the lower link bar (34). In the unfolded state, the longitudinal axis (X1) of each lower link bar (34) is offset from the central axis (L).

[0020] Specifically, referring to FIGS. 3, 4, 6 and 8, the support rod (201) is rotatable between a folded position (see FIG. 4) and an unfolded position (see FIG. 3) relative to the pivot seat unit (1). In the folded position, as illustrated in FIGS. 4 and 6, the upper end (22) of the support rod (201) is close to the central axis (L), the lower end (23) of the support rod (201) is close to the central axis (L), the synchronization seat (31) is adjacent to the pivot seat unit (1), and the longitudinal axis (X1) of each lower link bar (34) extends substantially along the central axis (L).

[0021] In the unfolded position, as illustrated in FIGS. 3 and 8, the upper portion (22) of the support rod (21) is spaced apart from the central axis (L) to form a support surface (S), the lower portion (23) of the support rod (21) is spaced apart from the central axis (L), the synchronization seat (31) is spaced apart from the pivot seat unit (1), and each lower link bar (34) is inclined with respect to the corresponding support rod (201) and extension stem (32). A support plate (8) is placed on the support surface (S). The upper portion of the extension stem (32) is connected to the support plate (8).

[0022] As illustrated in FIG. 5, in this embodiment, the rotation axis (L1) of each pivot axis (17) is nearly perpendicular to both the central axis (L) and the corresponding rod surface (25). In the position where the support rod (201) is extended, the upper portions (22) are not aligned with each other and do not interfere with each other, and together form a support surface (S) with a larger area. This is especially true when compared to a conventional tripod, where the area of ​​the support surface formed by the upper portions of the support legs rotatably connected to the support seat and the support member is smaller. Furthermore, in a conventional tripod, each pivot axis extends tangentially to the support seat through the corresponding leg and pivot protrusion, so the upper portions of the legs protruding from the support seat may interfere with each other during tripod operation. Additionally, each pivot head protrudes from the leg corresponding to the slide ring, and the pivot pin extends tangentially to the slide ring through the pivot head and the corresponding link bar. Unlike conventional tripods, in this embodiment, each pivot axis (L2) is perpendicular to the central axis (L) direction and extends perpendicularly to the corresponding peripheral wall section (311) of the hub (301) (see FIG. 7), and each shaft axis (L3) extends perpendicularly to the rod surface (25) of the corresponding support rod (201). That is, each pivot axis (L2) and each shaft axis (L3) extend in the width direction of the lower link bar (34) through the lower link bar (34). Thus, the lower link bar (34) moves and unfolds to the unfolded position together with the support rod (201) without interference, and the structural strength of the support rod (201) is improved in the unfolded position. In addition, the gap between the synchronization sheet (31) and each support rod (201) is minimized in the folded position, making the tripod support device more compact. Furthermore, each lower link bar (34) is closely attached to the synchronization sheet (31) and can rotate relative to it. Therefore, the thickness and width of the lower link bar (34) can be made smaller, so that its size and weight can be reduced.

[0023] In this embodiment, when the extension stem (32) extends upward from the synchronization sheet (31) and is connected to the support plate (8) of the support surface (S), pulling the support plate (8) causes the synchronization sheet (31) to move along the central axis (L) and the lower link bar (34) to rotate synchronously, making it convenient to use so that the support rod (201) can be unfolded or folded. To unfold the support rod (201), one of the support rods (201) is rotated outwardly relative to the pivot sheet unit (1), causing one lower link bar (34) to rotate and the synchronization sheet (31) to move downward, while the remaining two support rods (201) rotate simultaneously to unfold. Each support rod (201) and each lower link bar (34) rotate relative to each other to move the support rod (201) from the folded position to the unfolded position. When the biasing member (33) stores biasing force in the folded position, pulling the support plate (8) or one support rod (201) releases the biasing member (33), causing the synchronization sheet (31) to move downward to unfold the lower link bar (34) and allow the support rod (201) to easily move from the folded position to the unfolded position. In other modified embodiments, the extension stem (32), the biasing member (33), and the receiving groove (16) may not be required.

[0024] In summary, when the rotation axis (L1) of each pivot axis (17) is nearly perpendicular to both the center axis (L) and the bar surface (25) of the corresponding support bar (201), the upper portion (22) of the support bar (201) forms a larger support surface (S) in the unfolded position to support a larger and heavier support plate (8) (e.g., the chair plate of FIG. 1). Additionally, as each pivot axis (L2) is perpendicular to the center axis (L) direction and extends perpendicularly to the corresponding peripheral wall section (311) of the hub (301), and each shaft axis (L3) extends perpendicularly to the bar surface (25) of the corresponding support bar (201), the lower link bar (34) moves and unfolds together with the support bar (201) without interference, and the structural strength of the support bar (201) is improved in the unfolded position.

[0025] Referring to FIGS. 13 and 14, in the second embodiment, the tripod support device includes a pivot seat unit (1), a support unit (2), and an operation synchronization mechanism (3).

[0026] The lower pivot portion (24) of each support rod (201) of the support unit (2) has an enlarged head (242) formed at one end of the pivot shaft (241).

[0027] The operation synchronization mechanism (3) includes a synchronization sheet (31), an extension stem (32), a biasing member (33), and three lower link bars (34). The synchronization sheet (31) has a hub (301) and three link protrusions (302) that protrude from the hub (301) and are spaced apart from each other at an angle with respect to a central axis (L). Referring to FIG. 15, the link pin (312) of each link protrusion (302) is L-shaped and has a link end (314) connected to a corresponding peripheral wall section (311) of the hub (301), and a distal end (315) that extends from the link end (314), is bent, and is connected to a stop (313). The stop (313) is formed on the distal end (315) and extends upward from the distal end (315). The distal end (315) of each link pin (312) is formed adjacent to the stop portion (313) and has upper and lower inclined surfaces (318) inclined toward each other from the distal end (315) toward the connecting end (314). The connecting end (314) of each link pin (312) is in the form of a pivot pin and extends radially from the corresponding peripheral wall section (311) and crosses it. That is, the distal end (315) extends transversely to the link end (314) and has an L-shaped profile, and the stop portion (313) extends transversely to the distal end (315) and has an L-shaped profile.

[0028] The first pivot hole (343) of each lower link bar (34) is in the form of an elongated hole having a fan-shaped enlarged pivot section (344) and an arched hook section (345) opposite the enlarged pivot section (344) along the longitudinal axis (X1). The first pivot hole (343) has an inner diameter greater than the width of the connecting end (314) and the width of the distal end (315). Specifically, the hook section (345) has an inner diameter not smaller than the width of the connecting end (314). The enlarged pivot section (344) has a widest portion having an inner diameter not smaller than the width of the distal end (315). As shown in FIG. 14, the second link end (342) of each lower link bar (34) has a second pivot hole (346), the inner diameter of which is larger than the outer diameter of the pivot shaft (241) and smaller than the outer diameter of the extended head (242).

[0029] While the synchronization sheet (31) moves along the central axis (L) with respect to the pivot sheet unit (1), the lower link bar (34) rotates with respect to the support bar (201) corresponding to the synchronization sheet (31), and the first link end (341) of each lower link bar (34) slides over the corresponding link protrusion (302) and is stopped by the stop part (313), so that the second link end (342) of each lower link bar (34) can rotate with respect to the pivot shaft (241) of the lower pivot part (24) of the support bar (201). The second link end (342) is prevented from being removed from the pivot shaft (241) by the corresponding extended head (242). At the same time, referring to FIGS. 14, FIGS. 16a, FIGS. 16b, and FIGS. 16c, the support rod (201) rotates around the central axis (L), the lower link bar (34) is pulled by the support rod (201), and as the synchronization sheet (31) is pulled by the lower link bar (34), the synchronization sheet (31) rotates around the central axis (L). Thus, the support rod (201) rotates smoothly with respect to the pivot sheet unit (1).

[0030] When the support rod (201) is operated to fold toward the central axis (L) and the inclined surface (318) of the distal end (315) of each link protrusion (302) slides into the enlarged pivot section (344) of the first pivot hole (343) of the lower link bar (34), the synchronization sheet (31) rotates in the opposite direction around the central axis (L) and returns to its original angular position.

[0031] Referring to FIGS. 17 and 18, in the third embodiment, the hub (301) of the operation synchronization mechanism (3) has a peripheral wall (316) surrounding a central axis (L) and three or more pivot lugs (317) extending radially from the peripheral wall (316) and spaced apart from each other at an angle. The link end (314) of each link protrusion (302) is pivotally connected to the corresponding pivot lug (317) and is in the form of a pivot pin extending laterally. A stop (313) is positioned opposite the link end (314) along a centerline (L4) that is nearly perpendicular to the direction of the central axis (L). The stop (313) is in the form of a disc having a disc surface that is slightly inclined with respect to the centerline (L4). The first link end (341) of each lower link bar (34) has a first pivot hole (343) in the shape of a circular hole having an inner diameter that is larger than the width of the link end (314) and smaller than the outer diameter of the disk surface of the stop portion (313).

[0032] As illustrated in FIGS. 19 and 20, in the fourth embodiment, each support rod (201) of the support unit (2) has an upper tube (26), a lower tube (27) telescopically connected to the upper tube (26), and a protective sleeve (28) slidably sleeved around the lower tube (27). A lower pivot portion (24) is formed over the corresponding protective sleeve (28) so that a second link end (342) of each lower link bar (34) is pivotally connected to the protective sleeve (28). The lower tube (27) of each support rod (201) has two abutting protrusions (271, 272) that restrict the sliding movement of the protective sleeve (28) relative to the lower tube (27). The lower tube (27) can be shifted between an extended state and a retracted state relative to the upper tube (26). In the expanded state, the lower tube (27) is secured to the upper tube (26) in a known manner, such as with biasing pins and holes.

[0033] When the support rod (201) is operated to rotate from a folded position to an unfolded position, and when the support rod (201) is operated to rotate from an unfolded position to a folded position, the lower link bar (34) rotates simultaneously to unfold or fold the support rod (201). Each lower link bar (34) moves the corresponding protective sleeve (28) along the corresponding lower tube (27), and the movement of the protective sleeve (28) is restricted by the contacting protrusions (271, 272). When the support rod (201) is in the unfolded position, each protective sleeve (28) comes into contact with the upper contacting protrusion (271) and stops.

[0034] As illustrated in FIG. 21, when the support rod (201) is in a folded position, each lower tube (27) can be retracted into the corresponding upper tube (26). While the lower tube (27) is retracted, the contacting protrusions (271, 272) receive force and pass through the corresponding protective sleeve (28).

[0035] As shown in the drawing, the tripod support device has a simple structure that provides a wider carrying surface, and the folding and unfolding movements of the support rod (201) are smooth.

[0036] In the foregoing description, numerous specific details have been presented to provide a complete understanding of the embodiments for illustrative purposes. However, those skilled in the art will understand that one or more other embodiments may be implemented even without some of these specific details. Furthermore, throughout this specification, references to "one embodiment," "one embodiment," or ordinal numbered embodiments, etc., imply that specific features, structures, or characteristics may be included in the practice of this disclosure. It should also be understood that various features may occasionally be grouped together in one embodiment, drawing, or description to simplify the content of the disclosure and aid in understanding various inventive aspects. This does not imply that each of these features must be implemented together with all other features. In other words, if the implementation of one or more features or specific details in the described embodiment does not affect the implementation of another one or more features or specific details, said one or more features may be selected and implemented alone without said other one or more features or specific details. Furthermore, it should be noted that, where appropriate in the practice of this disclosure, one or more features or specific details from one embodiment may be implemented together with one or more features or specific details from another embodiment.

[0037] Although the invention has been described in relation to what are considered exemplary embodiments, it should be understood that the invention is not limited to the disclosed embodiments but is intended to encompass various arrangements included within the spirit and scope of the broadest interpretation to include all variations and equivalent arrangements.

Claims

Claim 1 A tripod support device comprising: a pivot seat unit defining a central axis; a support unit pivotably connected to the pivot seat unit, wherein the support unit comprises at least three support rods, each of which pivotably extends through the pivot seat unit and terminates at an upper and lower end opposite each other and is angularly spaced apart from each other about the central axis, each of which is pivotably coupled to the pivot seat unit and has a pivot portion interposed between the upper and lower end and a lower pivot portion interposed between the pivot portion and the lower end, wherein the upper and lower end of the support rods are rotatable between a folded state in which the upper and lower end are close to the central axis and an unfolded state in which the upper and lower end are far from the central axis, and the upper end forms a support surface together in the unfolded state, wherein the support unit and the support rods are disposed between the support unit and the support rods and are movable along the central axis relative to the pivot seat unit, and an operating synchronization mechanism comprising at least three lower link bars, wherein the synchronization seat comprises a hub and the A tripod support device characterized by comprising an operation synchronization mechanism, wherein at least three link protrusions protrude from a hub and are arranged angularly spaced from each other about a central axis, each of the lower link bars has a first link end pivotably connected to each of the link protrusions and a second link end located opposite to the first link end and pivotably connected to each of the lower pivot portions of the support bars, and while the synchronization seat moves along the central axis relative to the pivot seat unit, the upper and lower portions of the support bars rotate between a folded state and an unfolded state by the lower link bars, and in the unfolded state, the longitudinal axis of each of the lower link bars is offset from the central axis. Claim 2 A tripod support device according to claim 1, wherein each link protrusion of the operating synchronization mechanism comprises a link end connected to the hub, a distal end extending from the link end, and a portion formed on the distal end extending upward from the distal end, such that while the synchronization sheet moves along a central axis relative to the pivot sheet unit, the lower link bars are rotated relative to the synchronization sheet and the corresponding support bar among the support bars, and the first link end of each of the lower link bars slides over the corresponding link protrusion among the link protrusions and is stopped by the stopper so as to allow the second link end to pivot relative to the lower pivot portion of the corresponding support bar among the support bars. Claim 3 A tripod support device according to claim 1, wherein the hub of the operation synchronization mechanism has a plurality of peripheral wall sections arranged angularly spaced from each other around a central axis, the link end of each of the link protrusions is in the form of a pivot pin extending radially from each of the peripheral wall sections, the distal end of each of the link protrusions extends across the link end, the stop of each of the link protrusions extends across the distal end, and the first link end of each of the lower link bars has a first pivot hole, and the inner diameter of the first pivot hole is greater than the width of the link end and the width of the distal end. Claim 4 A tripod support device according to claim 3, wherein the distal end of each of the link protrusions of the operation synchronization mechanism is formed adjacent to the stop portion and has an upper inclined surface and a lower inclined surface inclined toward each other from the distal end to the link end, and the first pivot hole of each of the lower link bars is in the form of an elongated hole having an enlarged pivot section and a hook section opposite to the enlarged pivot section along the longitudinal axis, the inner diameter of the hook section is not smaller than the width of the link end, and the enlarged pivot section has the widest part having an inner diameter not smaller than the width of the distal end. Claim 5 A tripod support device according to claim 3, wherein the lower pivot portion of each of the support rods of the support unit is mounted on a corresponding support rod among the support rods and has a pivot shaft extending radially and an enlarged head formed at one end of the pivot shaft, and the second link end of each of the lower link bars has a second pivot hole, and the inner diameter of the second pivot hole is larger than the outer diameter of the pivot shaft and smaller than the outer diameter of the enlarged head. Claim 6 A tripod support device according to claim 2, wherein the hub of the operation synchronization mechanism has a peripheral wall surrounding a central axis and at least three pivot lugs extending radially from the peripheral wall and spaced apart from each other at an angle, and the link end of each of the link protrusions is pivotably connected to each pivot lug and is in the form of a pivot pin extending laterally, and the stop is disposed opposite the link end along a centerline perpendicular to the central axis, and the stop is in the form of a disk having a disk surface inclined with respect to the centerline. Claim 7 A tripod support device according to claim 6, characterized in that the first link end of each lower link bar has a first pivot hole in the form of a circular hole having an inner diameter larger than the width of the link end. Claim 8 A tripod support device according to claim 6, wherein the lower pivot portion of each support rod of the support unit is mounted on a corresponding support rod among the support rods and has a pivot shaft extending radially and an enlarged head formed at one end of the pivot shaft, and the second link end of each of the lower link bars has a second pivot hole having an inner diameter larger than the outer diameter of the pivot shaft and smaller than the outer diameter of the enlarged head. Claim 9 A tripod support device according to claim 1, further comprising a support plate disposed on the support surface, wherein the operation synchronization mechanism further comprises an extension stem extending from the synchronization sheet toward the support plate along a central axis, the extension stem having an upper end connected to the support plate, and wherein the support plate can be pulled to synchronously rotate the support rod between a folded state and an unfolded state through the operation synchronization mechanism. Claim 10 A tripod support device according to claim 9, wherein the operating synchronization mechanism further comprises a biasing member wrapped around the extension stem by a sleeve and having an upper portion and a lower portion that respectively contact the pivot seat unit and the synchronization seat. Claim 11 A tripod support device according to claim 10, wherein the pivot seat unit has a receiving groove that is open downward to receive the upper portion of the biasing member. Claim 12 A tripod support device according to claim 1, wherein each of the support rods comprises an upper tube, a lower tube telescopically coupled to the upper tube, and a protective sleeve slidably wrapped around the lower tube, wherein the lower pivot portion is formed on the protective sleeve so that the second link end of each of the lower link bars is pivotally connected to the protective sleeve, and the lower tube is movable relative to the upper tube between an extended state and a contracted state, and is fixed relative to the upper tube in the extended state. Claim 13 A tripod support device according to claim 12, wherein each of the lower tubes of the support rods has at least one adjacent protrusion, and while the support rods are rotating, the protective sleeve slides along the lower tube and comes into contact with the adjacent protrusion in an unfolded state.

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