Articulated structure and articulated support device

Abstract

To provide a joint structure having a lock mechanism capable of preventing erroneous operation, and a joint type support device having the joint structure.SOLUTION: The articulated support device includes a base 10 at a proximal end, a support at a distal end for supporting an object to be supported, and a plurality of arms 30 arranged between the base and the support. A joint structure for rotatably connecting a base (second component) and an arm (first component) closest to the base is equipped with a lock mechanism M. The lock mechanism includes an operation ring 90 and an internal lock structure 100. The operation ring is arranged on the outer periphery of the shaft part 32 of the arm so as to be rotatable between a lock position and an unlock position. The internal lock structure 100 is disposed radially inward of the operating ring and is operative to inhibit rotation of the arm relative to the base when the operating ring is in the locked position and permit rotation of the arm relative to the base when the operating ring is in the unlocked position.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a joint structure that connects adjacent components so that they can rotate relative to each other, and to an articulated support device equipped with this joint structure. [Background technology]

[0002] The articulated support device shown in Patent Document 1 comprises, as its components, a base, a support for supporting an object to be supported, and a plurality of arms arranged in a single piece between the base and the support, with adjacent components rotatably connected to each other by an articulated structure around a vertical or horizontal axis of rotation.

[0003] The first arm closest to the base is rotatably connected to the base around a rotation axis perpendicular to the base by a joint structure. This joint structure is equipped with a locking mechanism that can prohibit rotation as needed. The locking mechanism includes a lever rotatably supported on the end of the first arm and an internal locking structure. When the lever is in the locked position, it prohibits rotation of the first arm relative to the base, and when the lever is in the unlocked position, it allows rotation of the first arm.

[0004] In Patent Document 2, a push button is used instead of a lever as a locking mechanism for locking the rotation between adjacent components. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6150890 [Patent Document 2] Patent No. 6603152 Summary of the Invention [Problem to be solved by the invention]

[0006] In the locking mechanisms of Patent Documents 1 and 2, locking and unlocking are performed by operating a lever or a push button, but these levers and push buttons protrude outward, which means that there is a risk of them being operated erroneously if an external force is unintentionally applied to the lever or push button. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a joint structure in which adjacent first and second components are connected to each other so as to be capable of relative rotation and which is provided with a locking mechanism, The locking mechanism is characterized by comprising an operating ring arranged on the outer periphery of the first component so as to be rotatable between a locked position and an unlocked position, and an internal locking structure arranged radially inside the operating ring, which operates to prohibit relative rotation between the first and second components when the operating ring is in the locked position, and which allows relative rotation between the first and second components when the operating ring is in the unlocked position. With this configuration, the operating ring for locking and unlocking does not require a portion that protrudes significantly outward for operation, so that unintended external forces are not applied to the operating ring, and erroneous operation can be avoided.

[0008] In one embodiment, the internal lock structure includes a lock member movably supported on the first component, a direction conversion means for converting rotation of the operating ring into movement of the lock member, and a lock receiving portion provided on the second component, When the operating ring is in the lock position, the lock member engages with the lock receiving portion, and when the operating ring is in the unlock position, the lock member is released from engagement with the lock receiving portion.

[0009] Preferably, the first component has a shaft portion, the second component has a bearing portion that supports the shaft portion rotatably about the rotation axis of the relative rotation, the operating ring is disposed on the outer periphery of the shaft portion of the first component and is supported rotatably about the rotation axis, the locking member comprises a lock pin that extends parallel to the rotation axis and is supported on the shaft portion of the first component so as to be axially movable, the direction converting means is disposed between the operating ring and the shaft portion of the first component and converts rotation of the operating ring into axial movement of the lock pin, the lock receiving portion includes at least one engagement hole formed in the bearing portion of the second component, and when the first component is in a predetermined relative rotation position with respect to the second component, the position of the lock pin coincides with the position of the engagement hole, and the positions of the lock pin and the engagement hole coincide and the lock pin is inserted into the engagement hole when the operating ring is in the locked position. According to this configuration, when the first component is in a predetermined relative rotation position, relative rotation between the first and second components can be reliably prohibited.

[0010] More preferably, at least one engagement hole of the lock receiving portion includes a plurality of engagement holes formed circumferentially spaced apart in the bearing portion of the second component, and when the first component is in a plurality of predetermined relative rotation positions with respect to the second component, the position of the lock pin coincides with the position of one of the plurality of engagement holes. According to this configuration, when the first component is in a plurality of predetermined relative rotation positions, the relative rotation between the first and second components can be reliably prohibited.

[0011] In one embodiment, the direction changing means includes a cam member connected to the operating ring and rotating together with the operating ring, a follower portion provided on the lock pin, and a spring that biases the lock pin to bring the follower portion into contact with the cam member, and as the operating ring rotates, the lock pin moves axially through the cam action between the cam member and the follower portion.

[0012] Preferably, the cam member has an inclined surface that converts rotation of the operating ring into axial movement of the lock pin, and first and second protrusions formed on both ends of the inclined surface, the first protrusion being located lower than the second protrusion, When the operating ring is in the locked position, the follower portion of the lock pin is located at a position beyond the first protrusion from the inclined surface, and when the operating ring is in the unlocked position, the follower portion is located at a position beyond the second protrusion from the inclined surface. With this configuration, the locked and unlocked positions of the operating ring can be maintained more stably.

[0013] Preferably, an auxiliary tube is fixed to the shaft portion of the first component, and the auxiliary tube has a support tube portion arranged on the inner circumference of the operating ring, and a circumferentially extending slit is formed in the support tube portion, and a connecting portion for connecting the cam member and the operating ring is inserted into the slit, and the slit and the connecting portion provide a rotation angle limiting means for limiting the rotation angle range of the operating ring between a locked position and an unlocked position. According to this configuration, the operating ring can be reliably rotated between the locked position and the unlocked position.

[0014] Preferably, the auxiliary tube has an adjacent tube portion axially adjacent to the operating ring, and marks indicating a locked position and an unlocked position are provided on the outer periphery of the adjacent tube portion, and an index that is aligned with the marks is formed on the outer periphery of the operating ring. With this configuration, it is possible to confirm the locked position and the unlocked position of the operation ring.

[0015] Another aspect of the present invention is an articulated support device including, as a plurality of components, a base at a base end, a support at a tip end that supports a supported object, and a plurality of arms arranged between the base and the support, wherein adjacent components are connected to each other so as to be rotatable relative to each other, The joint structure is characterized in that one of the base and the arm adjacent to the base is provided as the first component and the other is provided as the second component, the rotation axis extends vertically, and the first arm is horizontally rotatable relative to the base.

[0016] Preferably, the engagement hole is a long, narrow hole that is elongated in the radial direction, and there is play in the radial direction when the lock pin is inserted into the long hole. With this configuration, even if the shaft portion tilts relative to the bearing portion when an unbalanced load is applied to the support device, the lock pin can be prevented from interfering with the engagement hole, and damage to the lock pin can be prevented. [Effects of the Invention]

[0017] According to the present invention, an unintended external force is not applied to the operation ring that performs locking and unlocking, and erroneous operation can be avoided. [Brief explanation of the drawings]

[0018] [Figure 1A] 1 is a perspective view showing a monitor support device according to one embodiment of the present invention, with the second arm in a substantially horizontal position. [Figure 1B] FIG. 10 is a side view of the monitor support device with the second arm positioned approximately horizontally. [Figure 2] FIG. 10 is a side view of the monitor support device showing the angular range of vertical rotation of the second arm. [Figure 3A] FIG. 10 is a perspective view of the monitor support device showing the stored state in which the second arm is arranged along the first arm. [Figure 3B] FIG. 2 is a side view of the monitor support device showing the stored state. [Figure 4] 10 is an exploded perspective view showing a joint structure that rotatably supports a first arm on a base in the monitor support device. FIG. [Figure 5] FIG. 4 is a perspective view showing a bearing member of the base. [Figure 6] FIG. 2 is a perspective view showing the appearance of the joint structure. [Figure 7]FIG. 10 is a side view showing a cross section of the operation ring and auxiliary cylinder of the locking mechanism and an enlarged view of the internal locking structure in the joint structure, showing the state in which the first arm is unlocked. [Figure 8] 8 is a view corresponding to FIG. 7, showing a state in which the first arm is locked. [Figure 9] FIG. 2 is an enlarged longitudinal cross-sectional view of the joint structure, showing the first arm in an unlocked state. [Figure 10] 10 is a view corresponding to FIG. 9, showing a state in which the first arm is locked. [Figure 11] 10 and shows a state in which an unbalanced load is applied to the first arm. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multi-joint monitor support device (articulated support device) according to one embodiment of the present invention will now be described with reference to the drawings. The monitor support device is used, for example, for medical purposes. <General configuration and operation of the monitor support device> 1A and 1B, the monitor support device is configured by arranging multiple components in a series and rotatably connecting adjacent components with an articulated structure. Specifically, the monitor support device includes, as multiple components, a base 10 (second component) at the base end of the monitor support device, a support 20 at the tip, and a first arm 30 (first component), a second arm 40, and a third arm 50 arranged in this order from the base 10 toward the support 20.

[0020] The base 10 has a flat mounting surface 10a, which is fixed to a cart 1 or the like (an object to be mounted). A monitor 2 (an object to be supported) is attached to the support 20. By rotating the arms 30, 40, 50 and the support 20, the monitor 2 can be adjusted to a desired orientation and position.

[0021] The first arm 30 is inclined, and its base end is connected to the upper end of the base 10 so as to be horizontally rotatable about a vertical rotation axis L1. The base end of the second arm 40 is connected to the tip of the first arm 30 so as to be horizontally rotatable about a vertical rotation axis L2. The base end of the third arm 50 is connected to the tip of the second arm 40 so as to be horizontally rotatable about a vertical rotation axis L3. A connecting portion 21 protrudes from the back surface of the support 20, and this connecting portion 21 is connected to the tip of the third arm 50 so as to be vertically rotatable about a horizontal rotation axis L4.

[0022] The second arm 40 constitutes a parallel link mechanism with four horizontal rotation axes. As shown in Figure 2, the second arm 40 rotates vertically around its base end, allowing the positions of the third arm 50 and the support 20 to be adjusted in the up and down direction while maintaining their orientation and posture.

[0023] 3A and 3B, the monitor support device can be placed in a suitable storage position when not in use. That is, the second arm 40 is aligned with the first arm 30, and these arms 30, 40 are oriented so as not to interfere with the cart 1, and the support 20 and monitor 2 are oriented so as not to interfere with the arms 30, 40.

[0024] <Joint structure between the base and the first arm> The joint structure that rotatably supports the first arm 30 on the base 10 will be described with reference to FIGS. The base 10 has a cylindrical block 11 with a bottom at its upper end, and a cylindrical bearing member 12 fitted and fixed into the block 11. The block 11 and bearing member 12 together provide a bearing section that functions as described below. The bearing member 12 has a central hole 12a that extends along its central axis, and a flange 12b at its upper end. A thin resin bushing 13 is attached from the inner periphery of the upper end of the central hole 12a to the upper surface of the flange 12b.

[0025] The first arm 30 has an arm body 31 and a shaft member 32 (shaft portion) extending vertically downward from its base end. The shaft member 32 has a flange portion 33 and a small-diameter portion 34 below it. The small-diameter portion 34 is inserted into the upper part of the central hole 12a of the bearing member 12 via the bushing 13, and the flange portion 33 rests on the flange portion 12b of the bearing member 12 via the bushing 13, thereby rotatably connecting the first arm 30 to the base 10. The central hole 12a of the bearing member 12 and the central axis of the shaft member 32 provide the vertical rotation axis L1 described above.

[0026] Two support holes 12c are formed in the upper surface of the bearing member 12 near the central hole 12a, and a support pin 14 is inserted into one of the support holes 12c and protrudes from the upper surface of the shaft member 12. Note that the bushing 13 also has a hole 13a formed therein that corresponds to the support hole 12c and allows the insertion of the support pin 14. The upper end of the support pin 14 is inserted into an arc-shaped groove 35 formed in the lower surface of the flange 33 of the shaft member 32, thereby limiting the rotation of the first arm 30 to a predetermined angle range, for example, approximately 270°.

[0027] Friction torque generating means 70 is attached to the lower end of shaft member 32. Briefly, a support hole 36 is formed in shaft member 32 along the central axis (i.e., rotation axis L1), and a support rod 71 fixed to the bottom of bearing member 12 is inserted into the lower part of this support hole 36. A friction plate 72 is fitted non-rotatably onto the small-diameter portion of the lower end of support rod 71, and a disc spring 73 is also fitted onto the outside. By tightening a nut 74 threaded onto the small-diameter portion of support rod 71, the friction plate 72 comes into contact with the lower end surface of shaft member 32 by the force of disc spring 73, and friction torque is generated when shaft member 32 rotates relative to bearing member 12 as first arm 30 rotates.

[0028] <Lock mechanism configuration> As described above, the joint structure that rotatably connects the first arm 30 to the base 10 is equipped with the locking mechanism M. The first arm 30 is locked by the locking mechanism M at multiple rotation angles, for example, every 90 degrees, so that the rotation angle position can be maintained.

[0029] The locking mechanism M includes an auxiliary cylinder 80, an operating ring 90, and an internal locking structure 100 disposed radially inward of the auxiliary cylinder 80 and the operating ring 90. Auxiliary cylinder 80 is disposed so as to cover shaft member 32 of first arm 30 between arm main body 31 and bearing member 12, and is constituted by a pair of half bodies 80A, 80B as shown in Fig. 4. Auxiliary cylinder 80 is assembled and fixed to shaft member 32 by bringing half bodies 80A, 80B close to each other so as to sandwich shaft member 32 therebetween, fitting protrusions 81 formed on the inner periphery at the lower ends of half bodies 80A, 80B into grooves 33a formed on the outer periphery of annular flange 33 of shaft member 32, and engaging protrusions 82 formed on both circumferential ends of half body 80A with engaging receptacles 83 formed on both circumferential ends of half body 80B.

[0030] The lower part of the auxiliary cylinder 80 serves as a support cylinder part 85, and an operation ring 90 is supported on the outer periphery of this support cylinder part 85 so as to be rotatable about a vertical rotation axis L1. The upper part of the auxiliary cylinder 80 has a larger diameter than the support cylinder part 85, and serves as an adjacent cylinder part 86 that is adjacent to the operation ring 90 in the axial direction.

[0031] Elastic claws 87 defined by two vertical slits are formed at two circumferentially spaced locations on the support cylinder portion 85 of the half-split bodies 80A, 80B. An annular protrusion 91 is formed on the inner periphery of the operation ring 90, and when the operation ring 90 is fitted onto the support cylinder portion 85 of the auxiliary cylinder 80, the elastic claws 87 elastically deform and engage with the annular protrusion 91, thereby rotatably supporting the operation ring 90 on the outer periphery of the support cylinder portion 85. The support cylinder portion 86 of one half body 80A is formed with a circumferentially extending slit 88. The role of this slit 88 will be described later.

[0032] A mark 89a indicating the locked position and a mark 89b indicating the unlocked position are formed on the outer periphery of the adjacent cylindrical portion 86 of the half-split bodies 80A and 80B. A protrusion 92 (index) is formed on the operating ring 90 for aligning with these marks 89a and 89b.

[0033] As shown in Figures 4, 7 and 9, the internal lock structure 100 includes, on the first arm 30 side, a lock pin 102 (lock member) supported on the outer periphery of the shaft member 32 of the first arm 30 via a bracket 101, a cam member 103, and a spring 104 that biases the lock pin 102. In this embodiment, the lock pin 102 is disposed in a direction 180° opposite to the tilt direction of the first arm 30 when viewed from the rotation axis L1, but may be disposed in a direction that coincides with the tilt direction.

[0034] The lock pin 102 extends in the axial direction (parallel to the rotation axis L1) and is supported by the bracket 101 so as to be axially movable but unrotatable. The cam member 103 is slidable in the circumferential direction along the upper surface of the flange portion 33 of the shaft member 32. The cam member 103 has an inclined surface 103a and a first protrusion 103x and a second protrusion 103y located at both ends of the inclined surface 103a in the circumferential direction. The first protrusion 103x is located lower than the second protrusion 103y. The cam member 103 has an elongated through hole 103b formed along the inclined surface 103a, and the lock pin 102 passes through this through hole 103b.

[0035] The lock pin 102 is provided with a pair of follower portions 105 that protrude from its outer periphery. A spring 104 is disposed between the bracket 101 and the pair of follower portions 105, and urges the lock pin 102 downward, thereby bringing the pair of follower portions 105 into contact with the cam member 103. The cam member 103, spring 104, and follower portions 105 constitute a direction conversion means that converts the rotation of the operating ring 90 into axial movement of the lock pin 102, as will be described later.

[0036] A connecting portion 106 protrudes from the side surface of the cam member 103. This connecting portion 106 passes through a slit 88 formed in the support cylinder portion 85 of the auxiliary cylinder 80 and is fixed to the inner periphery of the operation ring 90. This connecting portion 106 abuts against one end of the slit 88 when the operation ring 90 is in the locked position, and abuts against the other end of the slit 88 when the operation ring 90 is in the unlocked position. Therefore, this connecting portion 106 and the slit 88 provide rotation angle limiting means that limits the rotation angle range of the operation ring 90 to between the locked position and the unlocked position, which will be described later.

[0037] 4, 5, and 9, the internal locking structure 100 of the locking mechanism M includes, as a configuration on the base 10 side, four (plural) engagement holes 108 (lock receiving portions) formed on the upper surface of the flange portion 12b of the bearing member 12. The engagement holes 108 are formed at equal intervals, for example, at intervals of 90°. In this embodiment, the engagement holes 108 are elongated holes that are long in the radial direction (direction extending radially from the rotation axis L1). The bushing 13 also has a hole 13b formed in a position corresponding to the engagement hole 108, the hole 13b having the same shape as the engagement hole 108.

[0038] <Operation of the locking mechanism> 6, the operation ring 90 can be rotated between an unlocked position where the protrusion 92 aligns with a mark 89b indicating the unlocked position of the adjacent tube portion 86 of the auxiliary tube 80, and a locked position where the protrusion 92 aligns with a mark 89b indicating the locked position, thereby locking and unlocking the first arm 30, as will be described later. Because the operation ring 90 does not require a protrusion that protrudes significantly outward for operation, it is possible to prevent accidental locking and unlocking operations.

[0039] When the operation ring 90 is in the unlocked position, the cam member 103, which moves in conjunction with the operation ring 90, is positioned to the far right in Figure 7, the follower portion 105 is in a position beyond the second protrusion 103y from the inclined surface 103a of the cam member 103, and the connecting portion 106 of the cam member 103 is in contact with one end of the slit 88 of the auxiliary barrel 80. Therefore, the unlocked position of the auxiliary barrel 80 is stably maintained.

[0040] When the operating ring 90 is in the unlocked position described above, the lock pin 102 is in the uppermost position against the spring 104 as shown in Fig. 7, and is located above the flange 12b of the bearing member 12 as shown in Fig. 9. Therefore, the first arm 30 is subject to the friction torque of the friction torque generating means 70 and can freely rotate horizontally relative to the base 10 within the aforementioned rotation angle range.

[0041] The first arm 30 can be locked at a predetermined rotation angle of 90° relative to the base 10 by a locking mechanism M. This will be described in detail below. When the first arm 30 is at the predetermined rotation angle, the lock pin 102 is positioned directly above one of the multiple engagement holes 108 formed in the flange portion 12b of the bearing member 12. In this state, the operation ring 90 is rotated clockwise in FIG. 6 to align the protrusion 92 of the operation ring 90 with the mark 89a that indicates the locked position. With this rotation, the cam member 103 moves leftward in FIG. 7, and the follower portion 105 rides over the second protrusion 103y and slides down the inclined surface 103a. As a result, the lock pin 102 descends and enters the engagement hole 108 as shown in FIG. 10, preventing the first arm 30 from rotating relative to the base 10.

[0042] 8, when the operating ring 90 is rotated to the locked position, the follower portion 105 reaches a position beyond the inclined surface 103a and the first protrusion 103x, and the connecting portion 106 of the cam member 103 abuts against the other end of the slit 88 of the auxiliary barrel 80. This stably maintains the locked position of the auxiliary barrel 80.

[0043] The first arm 30 may be locked at a predetermined angular position as follows. That is, when the first arm 30 is at a rotational angle position away from the predetermined angular position, the operating ring 90 is rotated from the unlocked position to the locked position. At this time, the lock pin 102 is circumferentially away from the engagement hole 108 of the bearing member 12 and does not descend, but is instead brought into contact with the upper surface of the bearing member 12 via the bushing 13 by the force of the spring 104. Therefore, the follower portion 105 is positioned above a point beyond the first protrusion 103x of the cam member 103 and is separated from the cam member 103. When the first arm 30 is rotated in this state and reaches a predetermined rotational angle, the lock pin 102 reaches one of the multiple engagement holes 108 and is lowered and inserted into the engagement hole 108 by the force of the spring 104, automatically locking the first arm 30.

[0044] As shown in Figure 10, in the normal locked state, the lock pin 102 is inserted into the longitudinal center of the elongated engagement hole 108. There is radial play between the lock pin 102 and the engagement hole 108. When an external force or the like applied to the monitor support device causes an unbalanced load in the vertical direction, for example, as shown by arrow A, to be applied to the first arm 30 as shown in Figure 11, the shaft member 32 tilts slightly, and the lock pin 102 is displaced in the direction of arrow B accordingly. However, in this embodiment, the engagement hole 108 is an elongated hole that is elongated in the radial direction (radial direction from the rotation axis L1), so displacement of the lock pin 100 is permitted. If the engagement hole 108 were a round hole with approximately the same diameter as the lock pin 102, there is a possibility that the lock pin 102 would interfere with the engagement hole 108 and be damaged when tilted due to the unbalanced load described above, but this inconvenience does not occur.

[0045] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. The articulated support device of the present invention is not limited to supporting a monitor, but can support a variety of other objects. In this embodiment, a lock pin that is movable in the axial direction is used as the lock member, but a rotatable lock member may also be used. An engagement protrusion may also be used as the lock receiving portion instead of an engagement hole. In this embodiment, the direction change means is provided in one place, but a plurality of direction change means may be provided at intervals in the circumferential direction. Contrary to this embodiment, the base may be the first component and the first arm may be the second component. In this case, the base is provided with an operating ring and a direction changing means, and the first arm is provided with a lock receiving portion. The locking mechanism of the present invention may also be installed in a joint structure between other components. The engagement hole may be a single hole. [Industrial Applicability]

[0046] The present invention can be applied to an articulated support device that supports a monitor or the like so that the position thereof can be adjusted. [Explanation of symbols]

[0047] 1 Medical cart (installation target) 2 Monitor (support target) 10 Base (component; second component) 11 Block (bearing part) 12 Bearing member (bearing part) 20 Support (Component) 30 First Arm (Component; First Component) 32 Shaft member (shaft part) 40 Second arm (component) 60 Third Arm (Component) 80 Auxiliary tube 85 Support cylinder part 86 Adjacent tube section + 88 Slit 89a Lock position mark 89b Mark indicating unlock position 90 Operation Ring 92 Protrusion (index) 100 Internal Locking Structure 102 Lock pin (locking member) 103 Cam member 103a Slope 103x 1st protrusion 103y 2nd protrusion 104 Spring 105 Follower Section 106 Connection section 108 Engagement hole (lock receiving part) M Locking Mechanism

Claims

1. A joint structure in which adjacent first and second components are connected to each other so as to be capable of relative rotation and which is provided with a locking mechanism, The locking mechanism is an operating ring disposed on the outer periphery of the first component so as to be rotatable between a locked position and an unlocked position; an internal locking structure disposed radially inside the operating ring, the internal locking structure operating to prohibit relative rotation between the first and second components when the operating ring is in a locked position and allowing relative rotation between the first and second components when the operating ring is in an unlocked position; A joint structure comprising:

2. the internal lock structure comprises a lock member movably supported on the first component, a direction conversion means for converting rotation of the operating ring into movement of the lock member, and a lock receiving portion provided on the second component, 2. The joint structure according to claim 1, wherein the locking member engages with the lock receiving portion when the operating ring is in the locked position, and the locking member is released from engagement with the lock receiving portion when the operating ring is in the unlocked position.

3. the first component has a shaft portion, and the second component has a bearing portion that rotatably supports the shaft portion about a rotation axis of the relative rotation, the operation ring is disposed on an outer periphery of the shaft portion of the first component and is supported rotatably about the rotation axis, the locking member comprises a locking pin extending parallel to the rotation axis and supported axially movably on the shaft portion of the first component, the direction conversion means is disposed between the operating ring and the shaft portion of the first component, and converts rotation of the operating ring into axial movement of the lock pin; the lock receiving portion includes at least one engagement hole formed in the bearing portion of the second component, and when the first component is in a predetermined relative rotation position with respect to the second component, the position of the lock pin coincides with the position of the engagement hole; 3. The joint structure according to claim 2, wherein the position of the lock pin and the position of the engagement hole coincide with each other, and the lock pin is inserted into the engagement hole when the operating ring is in the locked position.

4. 4. The joint structure according to claim 3, wherein the at least one engagement hole of the lock receiving portion includes a plurality of engagement holes formed at intervals in the circumferential direction in the bearing portion of the second component, and when the first component is in a plurality of predetermined relative rotation positions with respect to the second component, a position of the lock pin coincides with a position of one of the plurality of engagement holes.

5. the direction changing means includes a cam member connected to the operation ring and rotating together with the operation ring, a follower portion provided on the lock pin, and a spring that biases the lock pin to bring the follower portion into contact with the cam member, 4. The joint structure according to claim 3, wherein the lock pin moves in the axial direction via a cam action between the cam member and the follower portion as the operating ring rotates.

6. the cam member has an inclined surface that converts rotation of the operating ring into axial movement of the lock pin, and first and second protrusions formed on both ends of the inclined surface, the first protrusion being located lower than the second protrusion; 7. The joint structure according to claim 6, wherein when the operating ring is in the locked position, the follower portion of the lock pin is located at a position beyond the inclined surface and the first protrusion, and when the operating ring is in the unlocked position, the follower portion is located at a position beyond the inclined surface and the second protrusion.

7. an auxiliary cylinder is fixed to the shaft portion of the first component; the auxiliary cylinder has a support cylinder portion disposed on an inner periphery of the operation ring, and a circumferentially extending slit is formed in the support cylinder portion; 4. The joint structure according to claim 3, wherein a connecting portion for connecting the cam member and the operating ring is inserted into the slit, and the slit and the connecting portion provide a rotation angle limiting means for limiting the rotation angle range of the operating ring between a locked position and an unlocked position.

8. 8. The joint structure according to claim 7, wherein the auxiliary cylinder has an adjacent cylinder portion adjacent to the operation ring in the axial direction, and marks representing a locked position and an unlocked position are provided on the outer periphery of the adjacent cylinder portion, and an index that is aligned with the marks is formed on the outer periphery of the operation ring.

9. An articulated support device including a base at a base end, a support at a tip end that supports a support object, and a plurality of arms disposed between the base and the support, wherein adjacent components are connected to each other so as to be rotatable relative to each other, The joint structure according to claim 3 or 4, An articulated support device characterized in that one of the base and the arm adjacent to the base is provided as the first component and the other is provided as the second component, the rotation axis extends vertically, and the first arm is horizontally rotatable relative to the base.

10. The articulated support device according to claim 9, wherein the engagement hole is a long, narrow hole that is elongated in the radial direction, and when the lock pin is inserted into the long hole, there is play in the radial direction.

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