Rotary mechanism with lock function

Abstract

[Problem] To realize a rotary mechanism with a lock function whereby it is possible to, with a simple and easy-to-operate structure, position a rotary member in a state of no backlash. [Solution] A rotary mechanism with a lock function includes: a fixing member 10; a rotary member 20; a support shaft 30; a regulating pin 40; and an urging member 50. The support shaft 30 is fixed to either one of the fixing member 10 and the rotary member 20, and the regulating pin 40 is fixed to the other member. The one member is provided with a pair of right and left regulating pin passages β and a pair of left and right regulating pin engagement recesses γ. The other member is provided with a pair of right and left support shaft insertion holes α, which are long holes. One of the regulating pin engagement recesses γ and the support shaft insertion holes α is formed such that the width thereof narrows with progress inward. The rotary member 20 is urged in a locking direction by the urging member 50.

Description

Rotating mechanism with locking function

[0001] The present invention relates to a rotation mechanism with a locking function that allows a rotation member to be locked at a predetermined rotation position while rotating the rotation member relative to a fixed member.

[0002] As shown in Fig. 3 of Patent Document 1, a known rotation mechanism with a locking function is one in which the position of a rotation member 40 relative to a fixed member 30 can be adjusted in multiple stages by locking a locking portion 31 with one of a plurality of locking portions 31a (a latch-type rotation mechanism with a locking function). However, the latch-type rotation mechanism with a locking function has a problem in that the positioned rotation member is prone to rattle. In addition, there are problems in that the number of parts is large, the structure is complicated, and the manufacturing cost is high.

[0003] Also known as a rotation mechanism with a locking function is one in which the position of a head support side member 40 (a rotating member) relative to a stay side member 10 (a fixed member) can be adjusted in multiple stages by the meshing of face gears 11, 12 (a face gear-type rotation mechanism with a locking function), as shown in Figure 2 of Patent Document 2. However, in the face gear-type rotation mechanism with a locking function, the meshing between the face gears is shallow, which tends to result in insufficient locking force to lock the rotating member in a predetermined position. In addition, the face gear has a complex shape, which increases manufacturing costs.

[0004] Furthermore, as shown in Figure 7 of Patent Document 3, a known rotation mechanism with a locking function includes a fixed bracket 4 (fixed member), a movable bracket 3 (rotating member), a lock shaft 12 (restriction pin), and a lock shaft support shaft 11. In this rotation mechanism with a locking function, when the movable bracket 3 is rotated to a predetermined rotation position, a side surface 21 of an elongated hole 13 formed in the movable bracket 3 and a side surface 22 of the fixed bracket 4 form a wedge groove (a groove that narrows as it goes deeper), and the lock shaft 12 fits into the groove like a wedge. This allows the movable bracket 3 to be positioned relative to the fixed bracket 4 without any rattle.

[0005] However, in the rotation mechanism with locking function of Patent Document 3, the movable bracket 3 can be positioned without rattle at only one rotation position (the use position shown in Figure 4 of the document). Furthermore, in the rotation mechanism with locking function of the document, it is necessary to operate the lock release lever 30 (Figure 1 of the document) in order to unlock the movable bracket 3 (to remove the lock shaft 12 that is caught in the wedge groove), which is troublesome. Furthermore, there is also the problem that the structure becomes complicated, as it is necessary to incorporate the lock release lever 30, etc.

[0006] Japanese Patent No. 5976190 Japanese Patent Application Laid-Open No. 2022-071788 Japanese Patent No. 7042537

[0007] The present invention has been made to solve the above problems, and aims to provide a rotation mechanism with a locking function that can position a rotating member without rattle, with a simple and easy-to-operate structure. Another object of the present invention is to provide a rotation mechanism with a locking function that can strengthen the locking force of the rotating member.

[0008] The above problem is solved by a rotation mechanism with a locking function, which comprises a fixed member, a rotating member, a support shaft for supporting the rotating member rotatably relative to the fixed member, a restriction pin for restricting the rotation of the rotating member, and a biasing member, wherein the support shaft is fixed to one of the fixed member and the rotating member, and the restriction pin is fixed to the other member, the one member is provided with a restriction pin passage for moving the restriction pin when the rotating member rotates, and a pair of restriction pin locking recesses formed inward or outward in the rotation radius direction from both ends of the restriction pin passage, on the left and right, the other member is provided with a pair of left and right elongated support shaft insertion holes for inserting the support shaft, and either the restriction pin locking recesses or the support shaft insertion holes are formed to become narrower as they go deeper, This problem is solved by providing a rotation mechanism with a locking function, characterized in that the rotation member is biased by a biasing member in the locking direction (the direction in the rotation radius direction in which the regulating pin engages with the regulating pin engaging recess, or the direction in which the support shaft engages with the support shaft insertion hole).

[0009] In the rotation mechanism with locking function of the present invention, when the rotation member is rotated and the restricting pin moving through the restricting pin passage overlaps with the restricting pin locking recess, the biasing force of the biasing member moves the rotation member in the rotation radial direction, and the restricting pin is locked in the narrow portion of the restricting pin locking recess, or the support shaft is locked in the narrow portion of the support shaft insertion hole. This locks the rotation member in that rotation position. The locking force of the rotation member can be increased by increasing the distance from the support shaft to the restricting pin or by increasing the biasing force of the biasing member. Because the narrow portions are formed to become narrower toward the back, the restricting pin is wedged into the restricting pin locking recess, or the support shaft is wedged into the support shaft insertion hole. This allows the rotation member to be positioned (locked) in that rotation position without any rattle.

[0010] The lock on the rotating member can be released by moving the rotating member or a component attached to it (such as the headrest's headrest, a table top, or an ottoman's footrest) in the unlocking direction (the direction in which the restricting pin disengages from the restricting pin locking recess). This allows the rotating member to be unlocked without operating a lever or other unlocking operating mechanism. Furthermore, because there is no need to provide an unlocking operating mechanism, the structure of the rotation mechanism with locking function can be simplified.

[0011] In addition, in the locking pivot mechanism of the present invention, the pivot insertion hole, the restricting pin passage, and the restricting pin locking recess are provided in pairs on two surfaces (planar portions spaced apart in the left-right direction), allowing the pivoting member to be supported in a balanced manner at two or more locations relative to the fixed member. This makes it difficult for the pivoting member and the fixed member to twist. It also distributes the load on the pivoting member. In this case, by providing two or more restricting pins on the other member (the member to which the restricting pins are fixed) and providing two or more rows of restricting pin passages and restricting pin locking recesses on the restricting pin locking member, the pivoting member can be locked to the fixed member at a total of four or more locations. This further distributes the load on the pivoting member. This also allows the material (e.g., steel plate) from which the pivoting member and the fixed member are formed to be thinner. This also allows for a lighter weight of the locking pivot mechanism.

[0012] In the rotation mechanism with locking function of the present invention, it is also preferable that one of the pair of inner wall surfaces of the restriction pin locking recess is inclined at an angle (e.g., 20 to 40°) that allows slippage under a set load. This allows the restriction pin to disengage from the restriction pin locking recess when a load greater than a predetermined level is applied to the rotating member, thereby allowing the rotating member to slip relative to the fixed member. This configuration can be suitably employed when the rotation mechanism with locking function of the present invention is incorporated into a headrest, ottoman, etc.

[0013] The rotation mechanism with locking function of the present invention can be incorporated into various products that require the ability to lock a rotation member at a predetermined rotation position while rotating the rotation member relative to a fixed member. For example, by incorporating the rotation mechanism with locking function of the present invention into a headrest, the front-to-rear position of the headrest of the headrest can be locked at a set position. Furthermore, by incorporating the rotation mechanism with locking function of the present invention into a table, the table top of the table can be locked at a storage position or a use position (a set position). Furthermore, by incorporating the rotation mechanism with locking function of the present invention into an ottoman, the vertical position of the footrest of the ottoman can be locked at a set position. These headrests, tables, ottomans, etc. are suitable for installation in seats of moving bodies such as vehicles and airplanes.

[0014] As described above, the present invention makes it possible to realize a rotation mechanism with a locking function that can position a rotating member without rattle, with a simple and easy-to-operate structure. It is also possible to provide a rotation mechanism with a locking function that can strengthen the locking force of the rotating member.

[0015] 10A and 10B are diagrams showing a rotation mechanism with a locking function of a first embodiment as viewed from the front and from the side; FIG. 10B is a diagram showing the relationship between a support shaft and a support shaft insertion hole, and a restriction pin and a restriction pin passage in the rotation mechanism with a locking function of the first embodiment; FIG. 10C is a diagram showing a state in which a rotation member in a rotation mechanism with a locking function of a second embodiment is locked at each position as viewed from the side; FIG. 10D is a diagram showing a rotation mechanism with a locking function of a third embodiment as viewed from the front and from the side; FIG. 10E is a diagram showing a rotation mechanism with a locking function of a fourth embodiment as viewed from the front and from the side; FIG. 10F is a diagram showing a rotation mechanism with a locking function of a fifth embodiment; FIG. 10G is a diagram showing a rotation mechanism with a locking function of a sixth embodiment; FIG. 10H is a diagram showing a rotation mechanism with a locking function of a seventh embodiment; FIG. 10H is a diagram showing an example in which the support shaft insertion hole is formed to become narrower as it goes deeper; and FIG. 10H is a diagram explaining variations in the arrangement of each part.

[0016] Embodiments of the rotation mechanism with a locking function of the present invention will be described with reference to the drawings. Below, the rotation mechanism with a locking function of the present invention will be described using seven embodiments, from the first embodiment to the seventh embodiment, as examples. However, these are merely preferred embodiments, and the technical scope of the rotation mechanism with a locking function of the present invention is not limited to these embodiments. The rotation mechanism with a locking function of the present invention can be modified as appropriate within the scope of the invention.

[0017] 1. Rotation Mechanism with Locking Function of First Embodiment First, the rotation mechanism with locking function of the first embodiment will be described. Figures 1 and 2 show the rotation mechanism with locking function 1 of the first embodiment. Figure 1(a) shows the rotation mechanism with locking function 1 as seen from the front, and Figure 1(b) shows the rotation mechanism with locking function 1 as seen from the side. Figure 2 also shows the relationship between the support shaft 30 and the support shaft insertion hole α, and the restriction pin 40 and the restriction pin passage β in the rotation mechanism with locking function 1.

[0018] As shown in FIG. 1 , the rotation mechanism with locking function 1 of the first embodiment includes a fixed member 10, a rotation member 20, a support shaft 30, a restricting pin 40, and a biasing member 50. The fixed member 10 is fixed to an object in an immovable state, and the rotation member 20 is supported by the support shaft 30 in a rotatable state relative to the fixed member 10. An object to be rotatably attached to the object (such as a table top, a footrest of an ottoman, or a headrest of a headrest) is fixed to the rotation member 20. The restricting pin 40 restricts (locks) the rotation of the rotation member 20. The biasing member 50 biases the rotation member 20 in the locking direction. In the rotation mechanism with locking function 1 of the first embodiment, the biasing member 50 is a coil spring (tension spring) stretched from its natural length, with one end attached to the support shaft 30 and the other end attached to the restricting pin 40.

[0019] In the first embodiment of the locking mechanism 1, the fixed member 10 has a restricting pin 40 fixed thereto and a pair of left and right support shaft insertion holes α. The support shaft insertion holes α are elongated holes through which the support shaft 30 is inserted. Meanwhile, the rotating member 20 has a restricting pin passage β and a pair of left and right restricting pin locking recesses γ, to which the support shaft 30 is fixed. The restricting pin passage β is a portion through which the restricting pin 40 moves when the rotating member 20 rotates. In the first embodiment of the locking mechanism 1, the restricting pin passage β is formed in an arc shape centered on the support shaft 30. The restricting pin locking recesses γ are a portion that locks the restricting pin 40 when the rotating member 20 reaches a predetermined rotational position, locking the rotating member 20 in that rotational position. The restricting pin locking recesses γ are formed to become narrower as they extend deeper.

[0020] The restricting pin locking recess γ may be provided at least at one location in the restricting pin passage β, but in the first embodiment of the rotation mechanism with locking function 1, as shown in Fig. 2, the restricting pin locking recess γ is provided at three locations in each of the pair of left and right restricting pin passages β (at both ends and in the middle of the restricting pin passage β). This allows the rotation of the rotating member 20 to be locked at three locations. For example, at position P in Fig. 2, Ａ When the restriction pin 40 is locked in the restriction pin locking recess γ, the rotating member 20 is in the undeployed position (storage position), and the position P Ｂ When the restriction pin 40 is locked in the restriction pin locking recess γ, the rotating member 20 is in the mid-deployment position, and the position P Ｃ When the restriction pin 40 is locked in the restriction pin locking recess γ, the rotating member 20 can be set to the final deployment position (use position).

[0021] The direction in which the restriction pin locking recess γ is provided from the restriction pin passage β (either inward or outward in the rotation radius direction of the rotating member 20) is determined by the biasing direction of the biasing member 50. As already described, in the rotation mechanism with locking function 1 of the first embodiment, a tension spring is used as the biasing member 50, and the restriction pin locking recess γ is provided inward in the rotation radius direction of the rotating member 20 (toward the support shaft 30).

[0022] As the pivotable member 20 is rotated, when the restricting pin 40 overlaps one of the restricting pin locking recesses γ, the biasing force of the biasing member 50 (tension spring) moves the pivotable member 20 inward in the direction of the pivot radius (the pivotable member 20 is permitted to move in the direction of the pivot radius due to the elongated shape of the support shaft insertion hole α), and the restricting pin 40 is locked in the restricting pin locking recess γ. As mentioned above, the restricting pin locking recess γ is narrower as it approaches the back, so that the restricting pin 40 is wedged into the restricting pin locking recess γ. This allows the pivotable member 20 to be securely locked in its pivoted position without any rattle. The locking force of the pivotable member 20 can be increased by increasing the distance L ( FIG. 2 ) from the support shaft 30 to the restricting pin 40 or by increasing the biasing force of the biasing member 50.

[0023] The lock can be released by moving the rotating member 20 or a member attached thereto (such as the head rest of a headrest, the top of a table, or the foot rest of an ottoman) in the unlocking direction (the direction in which the restricting pin comes out of the restricting pin locking recess) against the biasing force of the biasing member 50. This allows the lock on the rotating member 20 to be released without operating an unlocking operating means such as a lever. Furthermore, since there is no need to provide an unlocking operating means, the structure of the rotation mechanism with locking function 1 can be simplified.

[0024] In the first embodiment of the locking pivot mechanism 1, as shown in FIG. 1( a), the pivot member 20 has a groove-shaped cross section with a pair of left and right sidewalls 21, and the fixed member 10 also has a groove-shaped cross section with a pair of left and right sidewalls 11. The pivot member 20 is disposed inside the fixed member 10 (in the groove). The above-mentioned restricting pin passage β and restricting pin locking recess γ are symmetrically provided on each of the pair of left and right sidewalls 21 of the pivot member 20. Furthermore, the support shaft insertion hole α is symmetrically provided on each of the pair of left and right sidewalls 11 of the fixed member 10. This allows the pivot member 20 to be supported in a balanced manner at two locations on the left and right relative to the fixed member 10, making the pivot member and fixed member less susceptible to twisting. Additionally, the load on the pivot member 20 can be distributed laterally, allowing the materials (e.g., steel plate) forming the pivot member and fixed member to be thinner. This allows the weight of the locking pivot mechanism 1 to be reduced.

[0025] In addition, in the rotation mechanism 1 with a locking function of the first embodiment, the final deployment position P Ｃ When the restriction pin 40 is locked in the restriction pin locking recess γ in FIG. 2, if a load equal to or greater than a specified value (set load) is applied to the rotating member 20, the restriction pin 40 will disengage from the restriction pin locking recess γ and slip. Specifically, one of a pair of inner wall surfaces in the restriction pin locking recess γ is inclined at an angle θ. This makes it possible to improve the performance of devices (headrests, ottomans, etc.) that use the locking rotation mechanism 1. The specific value of the angle θ is not particularly limited, but is typically in the range of 20 to 40°.

[0026] 2. Rotation Mechanism with Locking Function of Second Embodiment Next, a rotation mechanism with locking function of the second embodiment will be described. The description of the rotation mechanism with locking function of the second embodiment will be focused mainly on the configuration that differs from the rotation mechanism with locking function 1 of the first embodiment (FIGS. 1 and 2). Configurations of the rotation mechanism with locking function of the second embodiment that are not specifically mentioned can be similar to those described for the rotation mechanism with locking function 1 of the first embodiment.

[0027] 3A and 3B are side views showing states in which the rotating member 20 of the locking rotation mechanism 1 according to the second embodiment is locked at each position. Fig. 3A shows the rotating member 20 in the undeployed position (storage position), Fig. 3B shows the rotating member 20 in the mid-deployment position, and Fig. 3C shows the rotating member 20 in the final deployment position.

[0028] As already mentioned, in the first embodiment of the rotation mechanism with locking function 1 (FIGS. 1 and 2), the fixed member 10 has the restricting pin 40 fixed thereto and is provided with a support shaft insertion hole α, and the rotating member 20 has the support shaft 30 fixed thereto and is provided with a restricting pin passage β and a restricting pin locking recess γ. In contrast, in the second embodiment of the rotation mechanism with locking function, as shown in FIG. 3, the fixed member 10 has the support shaft 30 fixed thereto and is provided with a restricting pin passage β and a restricting pin locking recess γ, and the rotating member 20 has the restricting pin 40 fixed thereto and is provided with a support shaft insertion hole α.

[0029] As described above, in the locking rotation mechanism 1 of the second embodiment, compared to the locking rotation mechanism 1 of the first embodiment, the member that fixes the spindle 30 (the spindle fixing member) and the member that provides the spindle insertion hole α (the spindle inserting member) are reversed, and the member that fixes the restricting pin 40 (the restricting pin fixing member) and the member that provides the restricting pin locking recess γ (the restricting pin locking member) are also reversed. However, even if these are reversed, the same operation as the locking rotation mechanism 1 of the first embodiment can be achieved. However, in the locking rotation mechanism 1 of the second embodiment, the restricting pin locking recess γ is provided only at both ends of the restricting pin passage β, and no restricting pin locking recess γ is provided in the middle of the restricting pin passage β. Therefore, in the locking rotation mechanism 1 of the second embodiment, the rotating member 20 can be locked only at two positions: the undeployed position (the retracted position) and the final deployed position.

[0030] 3. Rotation Mechanism with Locking Function of Third Embodiment Next, a rotation mechanism with locking function of a third embodiment will be described. The rotation mechanism with locking function of the third embodiment will also be described, focusing mainly on the configuration that differs from the rotation mechanism with locking function 1 of the first embodiment (FIGS. 1 and 2). Configurations of the rotation mechanism with locking function of the third embodiment that are not specifically mentioned can be similar to those described for the rotation mechanism with locking function 1 of the first and second embodiments.

[0031] 4A and 4B are diagrams showing a rotation mechanism with a locking function 1 according to a third embodiment of the present invention, in which Fig. 4A shows the rotation mechanism with a locking function 1 as seen from the front, and Fig. 4B shows the rotation mechanism with a locking function 1 as seen from the side.

[0032] In the third embodiment of the rotation mechanism with locking function 1 shown in Figure 4, the correspondence between the spindle fixing member and spindle insertion member, as well as the regulation pin fixing member and regulation pin locking member, and the fixed member 10 and the rotating member 20 is the same as in the rotation mechanism with locking function 1 of the first embodiment (Figures 1 and 2), but the inside and outside of the fixed member 10 and the rotating member 20 are reversed compared to the rotation mechanism with locking function 1 of the first embodiment.

[0033] That is, in the first embodiment of the locking function-equipped rotation mechanism 1, as shown in FIG. 1(a), the width (left-right width) of the fixed member 10 is wider than the width (left-right width) of the rotating member 20, and the rotating member 20 is arranged inside the fixed member 10 (inside the groove), whereas in the third embodiment of the locking function-equipped rotation mechanism 1, as shown in FIG. 4(a), the width (left-right width) of the fixed member 10 is narrower than the width (left-right width) of the rotating member 20, and the fixed member 10 is arranged inside the rotating member 20 (inside the groove).

[0034] Accordingly, a pair of biasing members 50 are provided on both the left and right sides of the fixed member 10. Each biasing member 50 is a tension spring, with one end (lower end) connected to the support shaft 30 and the other end (upper end) connected to a flange portion at the top of the fixed member 10. Therefore, the biasing direction of the biasing member 50 on the rotating member 20 is opposite to that of the locking rotation mechanism 1 of the first embodiment. Therefore, the restricting pin engagement recess γ, which is provided facing inward in the rotation radius direction in the locking rotation mechanism 1 of the first embodiment, is provided facing outward in the rotation radius direction in the locking rotation mechanism 1 of the third embodiment, as shown in FIG. 4(b).

[0035] Furthermore, while the locking mechanism 1 of the first embodiment has an arc-shaped, groove-like (slit-like) restricting pin passage β, the locking mechanism 1 of the third embodiment has a wide restricting pin passage β, as shown in FIG. 4B. Even in this configuration, the rotating member 20 can be operated as desired. This is because the support shaft 30 is restricted by the support shaft insertion hole α and cannot move upward any further. The restricting pin passage β does not need to be groove-like (slit-like) to guide the restricting pin 40.

[0036] Furthermore, in the rotation mechanism with locking function 1 of the first embodiment, as shown in Fig. 2, the restriction pin 40 is engaged in the restriction pin engagement recess γ itself like a wedge. In contrast, in the rotation mechanism with locking function 1 of the third embodiment, as shown in Fig. 4(b), the restriction pin engagement recess γ in the storage position is formed in a wedge shape (narrowing toward the back), but each restriction pin engagement recess γ has a size that allows room for the restriction pin 40. However, when the stopper 22 provided on the rotation member 20 abuts against the stopper receiving portion 12 of the fixed member 10, the rotation member 20 is sandwiched between the stopper receiving portion 12 and the restriction pin 40, and the entire rotation member 20 is engaged like a wedge.

[0037] 9, the restricting pin locking recess γ may be formed straight (with a constant width), and the shaft insertion hole α may be formed so as to become narrower as it approaches the back. This allows the shaft 30 to be fitted into the shaft insertion hole α like a wedge. However, in this case, regardless of the position at which the rotating member 20 is locked, the shaft 30 will be fitted into the same part of the shaft insertion hole α, which can cause wear to occur around the shaft insertion hole α and on the shaft 30.

[0038] 4. Rotation Mechanism with Locking Function of Fourth Embodiment Next, a description will be given of a rotation mechanism with locking function of a fourth embodiment. Configurations not specifically mentioned in the rotation mechanism with locking function of the fourth embodiment can be similar to those described in the rotation mechanism with locking function 1 of the first, second, or third embodiment.

[0039] 5A and 5B are diagrams showing a fourth embodiment of the rotation mechanism with a locking function 1. Fig. 5A shows the rotation mechanism with a locking function 1 as seen from the front, and Fig. 5B shows the rotation mechanism with a locking function 1 as seen from the side.

[0040] In the rotation mechanism 1 with locking function of the fourth embodiment shown in Fig. 5, the correspondence between the spindle fixing member, spindle insertion member, restriction pin fixing member, restriction pin locking member, and the fixed member 10 and the rotating member 20 is the same as in the rotation mechanism 1 with locking function of the first embodiment (Figs. 1 and 2) and the rotation mechanism 1 with locking function of the third embodiment (Fig. 4). However, in the rotation mechanism 1 with locking function of the first embodiment, as shown in Fig. 1(a), the width (left-right width) of the fixed member 10 is wider than the width (left-right width) of the rotating member 20, and the rotating member 20 is disposed inside the fixed member 10 (in a groove). 5A, in the locking rotation mechanism of the fourth embodiment, the width (left-right width) of the fixed member 10 is wider than the width (left-right width) of the rotating member 20 at the top of the locking rotation mechanism 1, and the rotating member 20 is disposed inside (in the groove) of the fixed member 10, whereas the width (left-right width) of the fixed member 10 is narrower than the width (left-right width) of the rotating member 20 at the bottom of the locking rotation mechanism 1, and the fixed member 10 is disposed inside (in the groove) of the rotating member 20. In this way, the same operation can be achieved even if the fixed member 10 and the rotating member 20 are switched between inside and outside depending on the location.

[0041] Furthermore, while the first embodiment of the locking mechanism 1 has only one restricting pin 40 as shown in FIG. 1 , the fourth embodiment of the locking mechanism 1 has two restricting pins 40 as shown in FIG. 5 . The restricting pins 40 are integrally connected. Accordingly, the restricting pin passage β and other passages are provided in two stages. That is, in addition to the restricting pin passage β formed by the arc-shaped slit, the lower edge of the rotating member 20 also functions as the restricting pin passage β. Of the two restricting pins 40, one (upper) restricting pin 40 moves through the restricting pin passage β, and the other (lower) restricting pin 40 moves through the restricting pin passage β. This allows the rotating member 20 to be locked to the fixed member 10 at a total of four locations: a pair on the left and right and two levels above and below.

[0042] 5. Fifth Embodiment of Rotation Mechanism with Locking Function Next, a description will be given of a fifth embodiment of the rotation mechanism with locking function. Configurations not specifically mentioned in the fifth embodiment of the rotation mechanism with locking function can be similar to those described in the rotation mechanism with locking function 1 of the other embodiments.

[0043] Fig. 6 is a diagram showing a rotation mechanism with a locking function 1 of the fifth embodiment. As shown in Fig. 6, the rotation mechanism with a locking function 1 of the fifth embodiment is incorporated into a headrest installed in a vehicle seat. In the rotation mechanism with a locking function 1, the fixed member 10 is fixed so as not to move relative to the headrest stay, and the rotation member 20 is fixed so as not to move relative to the head receiving portion 103. The headrest stay is attached to the backrest of the seat so as to be movable up and down (height adjustable). This makes it possible to lock the fore-and-aft position of the head receiving portion 103 at a set position. Specifically, from the state shown in Fig. 6(a), when the head receiving portion 103 is grasped and operated in the unlocking direction (the direction in which the restricting pin 40 comes out of the restricting pin locking recess γ) and the head receiving portion 103 is rotated forward, the head receiving portion 103 moves forward as shown in Fig. 6(b), and when the head receiving portion 103 is rotated backward from the state shown in Fig. 6(b), the head receiving portion 103 moves backward. This allows the head receiving portion 103 to be locked at an appropriate setting position according to the user's physique, the reclining angle of the backrest, etc., and makes it possible to use the headrest.

[0044] The locking mechanism 1 of the fifth embodiment has two restricting pin locking recesses γ, each of which is located on the opposite side of the support shaft 30 (one above the support shaft 30 and the other below the support shaft 30). Accordingly, the restricting pins 40 are also located in two positions. This allows the rotating member 20 to rotate widely even if the fixed member 10 and the rotating member 20 are thinned in the front-to-rear direction. In the example shown in FIG. 6 , the lower restricting pin 40 is fixed to the fixed member 10, and the lower restricting pin locking recess γ is provided in the rotating member 20, which is the same as the locking mechanism 1 of the first embodiment. However, the upper restricting pin 40 is fixed to the rotating member 20, which is the same as the support shaft 30, and the upper restricting pin locking recess γ is located in the same fixed member 10 as the support shaft insertion hole α. As will be explained later in "8. Others," the desired operation can be achieved even if the support shaft 30 and the regulating pin 40 are fixed to the same member, and the support shaft insertion hole α, the regulating pin passage β, and the regulating pin locking recess γ are arranged in the other same member.

[0045] 6. Rotation Mechanism with Locking Function of Sixth Embodiment Next, a rotation mechanism with locking function of a sixth embodiment will be described. For configurations not specifically mentioned in the rotation mechanism with locking function of the sixth embodiment, the same configurations as those described in the rotation mechanism with locking function 1 of the other embodiments can be adopted.

[0046] FIG. 7 is a diagram showing a rotation mechanism with a locking function 1 of a sixth embodiment. As shown in FIG. 7, the rotation mechanism with a locking function 1 of the sixth embodiment is incorporated into a table installed in a vehicle seat. The fixing member 10 is fixed immovably relative to the seat frame of the backrest, and the fixing member 20 is fixed immovably relative to the table top 101 of the table. This makes it possible to lock the position of the table top 101 in a storage position (position shown by phantom lines) or an in-use position (position shown by solid lines). Therefore, the table top 101 can be firmly supported when the table is in use, and noise caused by rattles during travel can be suppressed when the table is not in use.

[0047] 7. Rotation Mechanism with Locking Function of Seventh Embodiment Next, a rotation mechanism with locking function of the seventh embodiment will be described. For configurations not specifically mentioned in the rotation mechanism with locking function of the seventh embodiment, the same configurations as those described in the rotation mechanism with locking function 1 of the other embodiments can be adopted.

[0048] FIG. 8 is a diagram showing a rotation mechanism with a locking function 1 of a seventh embodiment. As shown in FIG. 8, the rotation mechanism with a locking function 1 of the seventh embodiment is incorporated into an ottoman that is attached to a vehicle seat. The fixed member 10 is fixed immovably relative to the seat frame of the seat, and the rotating member 20 is fixed immovably relative to the footrest portion 102. This makes it possible to lock the position of the footrest portion 102 in a stored position (position shown by phantom lines) or an in-use position (position shown by solid lines). Therefore, when the ottoman is in use, the footrest portion 102 can firmly support the feet, and when the ottoman is not in use, noise caused by rattle during travel can be suppressed.

[0049] 8. Others Figures 10A and 10B are diagrams illustrating variations in the arrangement of each part. Figure 10A shows a case in which both the support shaft 30 and the restriction pin 40 are fixed to the fixed member 10, and the support shaft insertion hole α, the restriction pin passage β, and the restriction pin locking recess γ are provided in the rotating member 20. Figure 10B shows a case in which both the support shaft 30 and the restriction pin 40 are fixed to the rotating member 20, and the support shaft insertion hole α, the restriction pin passage β, and the restriction pin locking recess γ are provided in the fixed member 10. In this way, even if the support shaft 30 and the restriction pin 40 are provided in the same member, and the support shaft insertion hole α, the restriction pin passage β, and the restriction pin locking recess γ are provided in the same member, the desired operation can be achieved. The configuration shown in Figure 10A can be used when the adjustment angle range of the rotating member 20 is 40° or less. Even when the adjustment angle range of the pivotable member 20 is wide (for example, 120° or more), if the support shaft insertion hole α is made not a simple elongated hole (a straight elongated hole) but a deformed elongated hole (a curved elongated hole) as shown in Figure 10(b), the support shaft 30 and the regulating pin 40 can be provided in the same member, and the support shaft insertion hole α, the regulating pin passage β, and the regulating pin locking recess γ can also be provided in the same member, thereby achieving the desired operation.

[0050] REFERENCE SIGNS LIST 1 Pivot mechanism with lock function 10 Fixed member 11 Side wall portion 12 Stopper receiving portion 20 Pivot member 21 Side wall portion 22 Stopper 30 Support shaft 40 Restriction pin 50 Biasing member 101 Top plate 102 Head receiving portion 103 Foot rest portion α Support shaft insertion hole β Restriction pin passage γ Restriction pin locking recess

Claims

1. A rotation mechanism with a locking function comprising: a fixed member; a rotating member; a support shaft for supporting the rotating member rotatably relative to the fixed member; a restriction pin for restricting the rotation of the rotating member; and a biasing member, wherein the support shaft is fixed to one of the fixed member and the rotating member, and the restriction pin is fixed to the other member, the one member is provided with a restriction pin passage for moving the restriction pin when the rotating member rotates, and a pair of restriction pin locking recesses formed inward or outward in the rotation radius direction from both ends of the restriction pin passage, on the left and right, the other member is provided with a pair of elongated support shaft insertion holes for inserting the support shaft, and either the restriction pin locking recesses or the support shaft insertion holes are formed to become narrower as they go deeper, A rotation mechanism with a locking function, characterized in that the rotation member is biased by a biasing member in a direction in the rotation radius direction in which the regulating pin engages with the regulating pin engaging recess or in which the support shaft engages with the support shaft insertion hole.

2. A rotation mechanism with a locking function according to claim 1, wherein one of the pair of inner wall surfaces of the regulating pin engagement recess is inclined at an angle that causes slippage under a set load.

3. A rotation mechanism with locking function as claimed in claim 1, wherein the restriction pin fixing member is provided with two or more restriction pins, the restriction pin locking member is provided with restriction pin passages and restriction pin locking recesses in two or more stages, and the rotation member is locked to the fixed member at a total of four or more points.

4. A headrest in which the front-to-rear position of the head support can be adjusted by using the rotation mechanism with locking function described in any one of claims 1 to 3.

5. A table in which the vertical position of the tabletop can be adjusted by using the rotation mechanism with locking function described in any one of claims 1 to 3.

6. An ottoman in which the vertical position of the footrest can be adjusted by using the rotation mechanism with locking function described in any one of claims 1 to 3.

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