JP5710831B1 - Headrest tilting device and headrest - Google Patents

Abstract

An object of the present invention is to provide a tilting device for a headrest capable of improving the productivity and reducing the weight of the headrest and improving its safety. A tilting device for a headrest 30 includes a ratchet plate 31 having a pair of left and right vertical wall portions 31a in which a ratchet hole 31a2 having a plurality of engagement teeth 31a1 is formed on an inner peripheral portion thereof, a front plate 32, The front plate urging means 37 and the engaging piece 33a1 are provided so as to protrude outward from the left and right side edges and are supported so as to be rotatable with respect to the front plate 32. A lock plate 33 whose length is 10 times or more of the tilt angle pitch of the engagement teeth 31a1 and rotates with respect to the front plate 32 at a rotation angle of 15? Or less, a lock urging means 34, and the engagement teeth The lock release means 35 for temporarily releasing the engagement between 31a1 and the engagement piece 33a1 and the resin cover 36 are used. [Selection] Figure 1

Description

  The present invention relates to a headrest tilting device capable of adjusting the tilting position (front-rear position) of a headrest, and a headrest using the headrest tilting device.

  As a headrest provided in an automobile seat, a ratchet mechanism adapted to the required strength and restricted dimensions and shape can be used to adjust the front-rear position with respect to the seat back. Are known. This makes it possible to reduce the gap between the head of the seated person and the headrest, and to reduce the distance of the head's back deflection when a rear-end collision occurs and the distance of the head's back deflection due to recoil in the case of a forward collision. This can reduce the damage to the seated person. Various types of headrests have been proposed so far.

  For example, the applicant can adjust the headrest in a stepwise manner from the initial position toward the front, but moves the headrest backward unless the ratchet is unlocked once the headrest is moved to the front limit position. A headrest (see Patent Document 1) having a structure that cannot be used is proposed. In the headrest of Patent Document 1, as shown in FIG. 2 of the same document, the length from the rotation center to the tip of the lock plate 50 is about three times the pitch of the downward engaging teeth 81, and the lock plate 50 is It is designed to be rotated at a large angle of about 30 to 45 degrees, and the locked state and the unlocked state are switched by changing the biasing direction of the overpass spring 60 (see the same document). (See paragraph 0032). However, in the headrest of Patent Document 1, due to structural limitations, the number of adjustment stages is limited to a limited number of stages (four stages in FIGS. 1 to 5 of the same document), and the biasing spring is a carry-over spring. In addition, there is a possibility that the lock may be released due to an impact, and there is still a problem in terms of strength in addition to the problem that the number of members is complicated and the weight increases.

  In addition, although the headrest disclosed in Patent Document 1 can be used without any problem for a lower-swing headrest, if it is used for an upper-swing headrest, the inertial force accompanying the weight of the headrest during a vehicle collision or sudden braking In addition to the possibility that the headrest may tilt forward beyond the limit position, if it is used for the headrest of the front seat, the seat occupant of the rear seat moves the headrest of the front seat forward in the event of a vehicle collision or sudden braking. And the headrest may be pushed forward beyond the limit position. Therefore, the headrest is structured so that when the headrest reaches the front limit position, the ratchet is unlocked and can return to the original rearmost position away from the head. Without being able to achieve the above-described effect of reducing damage to the seated person.

  Further, Patent Document 2 proposes a headrest having a structure in which the headrest cannot be returned to the original rear position unless the push button provided on the side of the headrest is pushed in to release the lock. However, this headrest has a structure in which the lock member is inserted and removed in the left-right direction to switch between lock and release, so that the adjustment pitch is naturally increased and the number of adjustment steps is small. In addition, the thickness of the member is large and the operation buttons are added, which further increases the weight. In addition, it becomes necessary to perform fine press processing and the like, which is a factor that hinders weight reduction and productivity improvement of the headrest. .

Japanese Patent No. 5536692 JP 2012-249869 A

  The present invention has been made to solve the above-mentioned problems, and can adjust the fine pitch by pursuing the shape and arrangement of the lock plate, can withstand high loads, is lightweight, and has a high productivity. A tilting device for use is provided. It is also an object of the present invention to provide a headrest using the headrest tilting device.

The above issues
A headrest tilting device that makes it possible to adjust the tilting position of the headrest forward by supporting the headrest frame in a rotatable state with respect to the headrest stay,
A ratchet plate comprising a pair of left and right vertical wall portions formed with ratchet holes having a plurality of engaging teeth in a part of the inner peripheral portion thereof, and integrally coupled to the headrest stay;
A front plate integrally coupled to the headrest frame;
Front plate urging means for urging the front plate to rotate backwards;
A pair of left and right engaging pieces for engaging with the engaging teeth are provided to protrude outward from the left and right side edges, and are supported in a rotatable state with respect to the front plate. A lock plate that has a length up to 10 times the tilt angle pitch of the engaging teeth and rotates at a rotation angle of 15 ° or less,
Lock urging means for constantly urging the lock plate in the locking direction;
Unlocking means for temporarily releasing the engagement between the engagement teeth and the engagement pieces by rotating a lock plate in the unlocking direction;
A resin cover covering the member;
This is solved by providing a tilting device for a headrest characterized by comprising

  The tilting device for a headrest according to the present invention employs a spring that constantly biases in the lock direction as the lock biasing means, instead of the overpass spring as shown in Patent Document 1, so that the biasing direction does not change, and the adjustment position In case of unintentional impact or vibration, it will not come off. Moreover, the tilting device for a headrest according to the present invention has a structure in which the headrest does not move beyond the front limit position even when a strong force is applied from the rear side of the headrest. Furthermore, in the tilting device for a headrest of the present invention, the ratchet mechanism and the engagement piece constituting the ratchet mechanism are provided in a pair on the left and right sides, and by receiving a load (force) on both left and right end surfaces, it is possible to adopt a plate steel plate, Since the ratchet plate provided with the ratchet hole and the lock plate provided with the engagement piece can be thinned, fine pitch adjustment can be performed. Furthermore, in the tilting device for a headrest according to the present invention, the ratchet plate and the lock plate can be formed by a normal press process other than the fine press process, and the productivity of the headrest can be increased.

In the head rest tilting device of the present invention, when viewed headrest from the side, the rotation center of the headrest frame and P _1, the rotation center of the lock plate and P _2, the engagement tooth and the engaging piece The angle θ formed by the line segment P ₁ P ₂ and the line segment P ₂ P ₃ is preferably 90 to 110 ° when the engagement point is P ₃ . This is because, if the angle θ is less than 90 °, a component force is generated in a direction in which the engagement teeth and the engagement piece are disengaged, whereas if the angle θ is 90 ° or more, the engagement is bitten. This is because a component force is generated in the direction to be generated. In addition, if it exceeds 110 °, the component force in the biting direction becomes too large, which may cause adverse effects such as member deformation.

In the tilting device for a headrest according to the present invention, the ratchet hole may have an open shape having a cut or an opening in the peripheral portion thereof, but the peripheral portion is left in a connected state in order to increase the strength. It is also preferable to have a shape (a shape having no cuts or openings in the peripheral portion). Incidentally, when a load of 980 N is applied from the front direction (head) to the head load input portion P ₄ in the headrest frame 20 in FIG. 2, the length of the line segment P ₁ P _{4 with} respect to the line segment P ₂ P ₃ is based on the principle of leverage since it is three times the load on the _{P 2} is about 3000N. Since the load is also comparable to P ₃ through the lock plate is applied, compressive and flexural strength front plate corresponding to its load, it is necessary to lock plate and the ratchet plate. The ratchet plate is usually made of a steel plate. In this case, the ratchet hole can be provided by processing a punched hole obtained by punching the vertical wall portion of the ratchet plate.

  In the headrest tilting device of the present invention, the plurality of engaging teeth are formed in the upper section of the inner peripheral portion of the ratchet hole, and the lower front section of the inner peripheral portion is used as a front stopper portion, and The upward end surface of the engagement piece is engaged with the engagement teeth from below to restrict the backward rotation of the headrest, and the downward end surface of the engagement piece is used as the front stopper portion. It is preferable to use a forward rotation restricting contact portion that abuts from above and restricts the forward rotation of the headrest.

  In the tilting device for a headrest according to the present invention, the form of the engaging teeth is not particularly limited as long as the engaging teeth can appropriately engage with the engaging piece, and various shapes other than a triangular shape can be adopted. . For example, as shown in FIG. 4, a drop-off preventing projection that contacts the downward end surface of the engagement piece engaged with the engagement tooth may be provided on the top of the engagement tooth. This configuration is limited to a mode (lock release button method) in which the lock release button must be pushed not only when moving the headrest backward but also when moving the headrest forward.

  In the headrest tilting device of the present invention, the specific configuration of the unlocking means is not particularly limited. For example, the unlocking means is provided with an unlocking button that is operated from the outside of the headrest and an inclined cam is provided at the tip thereof, and when the unlocking button is pushed, the inclined cam is unlocked on the lock plate. By abutting on the abutting portion, it is also possible to configure with an unlocking bar for rotating the lock plate in the unlocking direction and an unlocking bar urging means for urging the unlocking bar outward. In the following, this type of unlocking means may be referred to as a “button-equipped type unlocking means”.

Also, unlocking means
A switching pin fixed to the ratchet plate;
A guide bar integrally coupled to the front plate;
A resin piece inserted slidably into the guide bar;
Consisting of
The resin piece includes a switching contact piece A, a switching contact piece B, and a switching cam,
The lock plate has a switching cam contact portion;
In the locked state, while the switching contact piece A is in a free state without restriction with respect to the switching pin,
When a forward external force is applied to the headrest, the resin piece moves integrally with the guide bar, and the switching contact piece B contacts the switching pin at the foremost adjustment position.
When the headrest is operated further forward beyond the foremost adjustment position, the resin piece slides on the guide bar, the switching cam contacts the switching cam contact portion, and the lock plate rotates to move the engagement plate. Is unlocked and unlocked,
When the external force is no longer applied to the headrest, the headrest is returned to the rearmost adjustment position by the rearward rotation urging spring (front plate urging means), and the resin piece slides back to the original state. You can also.
Hereinafter, the unlocking means of this aspect may be referred to as “buttonless type unlocking means”.

The above issues are
A headrest tilting device of the present invention coupled to a headrest stay and a headrest frame;
An epidermis covering the resin cover with the headrest frame;
Cushion material made of foamed resin,
With
The resin cover is of a left and right split type having a left resin cover and a right resin cover for covering the tilting device for the headrest from the left and right, and a lock release bar guide support for guiding and supporting the lock release bar on either of them The problem can also be solved by providing a headrest characterized in that a portion is provided.

  The conventional headrest has a front and rear split resin cover, so when an impact force is applied in the front and rear direction of the headrest, the lock release button is misaligned if it has an unlock button. There was a possibility that the lock could not be released even if the unlock button was operated. In this regard, like the headrest of the present invention, the resin cover is divided into left and right structures, the front plate is sandwiched and the position and movement in the front-rear direction are restricted, so that the assembly accuracy is improved and the unlock button (unlock bar) Misalignment can be prevented so that the above problems do not occur.

  In the headrest of the present invention, the resin cover fixing structure is not particularly limited, but the front plate is provided with a resin cover engagement hole, and an engagement claw provided inside the resin cover is engaged with the resin cover engagement hole. Thus, it is preferable to fix the resin cover to the front plate. This makes it possible to accurately position the resin cover in the left-right direction with respect to the front plate and firmly fix both.

  In the headrest of the present invention, the lower surface portion of the resin cover is preferably a lower resin cover that can be separated from other portions of the resin cover. This is because the headrest stay insertion part for inserting the headrest stay is provided on the bottom surface of the resin cover in a pair of left and right. The diameter and pitch of the headrest stay vary depending on the specifications of each vehicle model, so the headrest stay insertion The dimensions and arrangement of the parts are not uniformly determined, but by adopting a structure in which the lower surface part of the resin cover can be separated, it is possible to meet all specifications by simply replacing the lower surface part. The lower resin cover is preferably provided with an engaging claw for integrally coupling to the left resin cover and the right resin cover. Thereby, it becomes possible to suppress rattling of the whole resin cover.

  As described above, according to the present invention, by devising the shape and arrangement of the lock plate and the lock urging means that constantly urges the lock plate in the engagement direction, the adjustment position is prevented from coming off, and the headrest tilt position is set. It is possible to provide a tilting device for a headrest that can be adjusted with a fine pitch, can withstand high loads, is lightweight, is compact in size and conforms to restricted dimensions and shapes, and has good productivity. It is also possible to provide a headrest using this headrest tilting device.

It is the back perspective view which exploded and showed the headrest of the first embodiment. It is sectional drawing which cut | disconnected the headrest of 1st embodiment by the plane perpendicular | vertical to the left-right direction, and sectional drawing cut | disconnected by the horizontal surface. It is sectional drawing which cut | disconnected the headrest of the 1st embodiment with the plane perpendicular | vertical to the front-back direction. It is a figure explaining the modification of the number of engagement teeth and a shape in the tilting apparatus for headrests of a 1st embodiment. In the headrest tilting apparatus according to the first embodiment, the relationship between the position (vector force) of the position of the rotation center P ₁ , P ₂ of the headrest frame and the lock plate and the engagement point P ₃ of the engagement teeth and engagement pieces will be described. It is a figure to do. It is a figure explaining the relationship between the contact angle and vector (component force) of the engagement tooth surface and the engagement piece (lock plate) in the headrest tilting device of the first embodiment. It is a figure explaining adjustment operation of the tilting device for headrests of the first embodiment. It is a figure explaining operation | movement of the tilting apparatus for headrests of a 2nd embodiment. It is sectional drawing which cut | disconnected the headrest of the 2nd embodiment by the plane perpendicular | vertical to the left-right direction.

  Hereinafter, preferred embodiments of the tilting device for a headrest and the headrest of the present invention will be described more specifically with reference to the drawings. In the following, the present invention will be described by taking two embodiments (first embodiment and second embodiment) as examples, but the technical scope of the present invention is not limited to these embodiments. Changes can be made as appropriate.

1. First, the headrest of the first embodiment will be described. FIG. 1 is an exploded rear perspective view of the headrest of the first embodiment. Fig.2 (a) is sectional drawing which cut | disconnected the headrest of the 1st embodiment by the plane perpendicular | vertical to the left-right direction. FIG.2 (b) is sectional drawing which cut | disconnected the headrest of the 1st embodiment by the horizontal surface. FIG. 3 is a cross-sectional view of the headrest of the first embodiment cut along a plane perpendicular to the front-rear direction. 3 and 2B, only the left half of the headrest (left side when the headrest is viewed from the rear) is shown.

  1-3, the headrest of the first embodiment includes a headrest stay 10, a headrest frame 20, a headrest tilting device 30 coupled to the headrest stay 10 and the headrest frame 20, a resin cover 36, The skin 40 and the cushion material 50 are provided. The headrest is configured such that after the headrest tilting device 30 is accommodated inside the resin cover 36, the foamed resin (cushion material 50) and the skin 40 are covered.

1.1 Headrest Tilt Device As shown in FIG. 1, the headrest tilt device 30 includes a ratchet plate 31 that is integrally coupled to the headrest stay 10 by welding, a front plate 32 that is integrally coupled to the headrest frame 20, A lock plate 33 supported in a rotatable manner with respect to the plate 32, a lock urging means 34, a lock releasing means 35 for rotating the lock plate 33 in the unlocking direction, and a resin covering the members 31 to 35. A cover 36 is provided. The front plate 32 is pivotally supported by pins 101 that are inserted and fixed in the left-right direction with respect to the ratchet plate 31, and the lock plate 33 is widely held by the curved surface of the front plate 32 and is inserted in the left-right direction with respect to the front plate 32. It is supported by a pin 102 to be fixed. The headrest tilting device 30 is configured to make it possible to adjust the tilting position of the headrest by supporting the headrest frame 20 so as to be rotatable with respect to the headrest stay 10.

(1) Ratchet plate The ratchet plate 31 is a high-strength steel plate having a thickness of 1.6 to 2 mm, and a ratchet hole 31a ₂ having a plurality of engagement teeth 31a ₁ is formed in a part of the inner peripheral portion thereof. The plate-like member is provided with a pair of left and right vertical wall portions 31a and a back wall portion 31b that connects the rear side edges of the pair of left and right vertical wall portions 31a, and is formed in a U-shaped horizontal section. The ratchet hole 31a ₂ is formed by punching out the vertical wall portion 31a of the ratchet plate 31 with a normal press, and is an independent punching hole left in a connected state without a break or the like in its peripheral portion. As shown in FIG. 2, the upper section of the inner peripheral portion of the ratchet hole 31a ₂ is a front / rear position adjusting section in which triangular engagement teeth 31a ₁ are formed at eight locations, and the lower front section. Is a front stopper. For this reason, in the first embodiment, the front and rear positions of the headrest are the eight engaging teeth 31a ₁ and the upper rear section of the ratchet hole 31a ₂ (this portion is also conceptually included in the engaging teeth). ) And 9 levels of fine adjustments are possible. In addition, in order to make it easy to understand except FIG.1 and FIG.2, it has shown in figure with the number of teeth of 4 fewer than actual.

By the way, the engaging teeth 31a ₁ are not limited to the simple triangular shape described above, and may be in a more complicated form. FIG. 4 is a diagram for explaining a modification of the number and shape of the engaging teeth 31a ₁ in the headrest tilting device 30 of the first embodiment. For example, the engaging teeth 31a _1, as shown in FIG. 4 (a), the top portion, disengagement prevention projection 31a ₃ abutting the top of the engaged side surfaces of the engagement piece 33a ₁ to engaging tooth 31a ₁ Can also be provided. Thereby, in addition to the lock urging means 34 that always operates, it is possible to prevent double dropping. Further, as shown in FIG. 4B, the engagement teeth 31a ₁ are provided with drop-off prevention protrusions 31a ₃ that come into contact with the downward end surfaces of the engagement pieces 33a ₁ engaged with the engagement teeth 31a ₁ as shown in FIG. It can also be provided. Thereby, even when moving the headrest tilting device 30 forward, it is possible to operate the lock release means 35. Incidentally, as described above, the engaging teeth 31a ₁ in FIG. 4 (a), (b) is for clarity, are illustrated actually smaller number of teeth 4 than.

(2) Front plate The front plate 32 is a high-strength steel plate having a thickness of 1.6 to 2 mm, and is a horizontal section hat in which the left and right sides of the headrest frame 20 made of a thin pipe (diameter 10 to 12 mm, thickness 1 mm) are welded and fixed. -Shaped front wall 32a, a pair of left and right protruding walls 32b provided to protrude rearward from both lower ends of the front wall 32a, and a rear wall that holds the lock plate 33 so as to be rotatable with a wide curved surface. It has a plate-like member having a 32a _1. A resin cover engagement hole 32b ₁ for engaging an engagement claw 36e provided on the inner side of a resin cover 36, which will be described later, is provided and fitted to the protruding wall portion 32b. Further, as shown in the cross-sectional view of FIG. 2B, the front plate 32 is sandwiched by the resin cover 36 so as to be integrally coupled.

(3) Lock plate The lock plate 33 is a high-strength steel plate having a thickness of 1.6 to 2 mm, and the rotation angle is set to 15 ° or less by making the length of the tilt angle pitch of the engagement teeth 31a ₁ more than 10 times. It is a plate-like member having a V-shape in side view, which is composed of a main body 33a and a folded portion 33b, and a pair of left and right engaging pieces projecting outwardly on both left and right edges of the main body 33a. 33a ₁ are mounted on the left and right side edges of that occasion back portion 33b, releasing a pair of right and left locking projecting outwardly bar abutment portion 33b ₁ is provided. However, the lock plate 33, by providing a portion corresponding to the unlocking bar contact portion 33b ₁ to the main body portion 33a, it is also possible to form without the turning portion 33b. The lock plate 33 is such that its pair of left and right engagement pieces 33a ₁ can be engaged with the engaging teeth 31a ₁ provided on the inner peripheral portion of the ratchet hole 31a _2, the pair of left and right engagement pieces 33a ₁ ratchet disposed from the inside of each of the pair of left and right vertical wall portions 31a in the plate 31 so that the state of being inserted into the ratchet hole 31a _2. The upward end surface of the engagement piece 33a _{1 is in contact with} the engagement teeth 31a ₁ provided in the front / rear position adjustment portion (upper section) of the ratchet hole 31a ₂ from below to restrict the backward rotation of the headrest. has a engaging portion, the downward end face of the engagement piece 33a ₁ is rotated forward regulations that restrict the forward rotation of the headrest abuts from above to the front stopper portion of the ratchet hole 31a ₂ (lower front section) It is a contact part. One end of the lock plate 33 is rotatably held with a wide curved surfaces wall section 32a ₁ after the front plate 32 so as to receive a strong force.

(4) locking biasing means locking biasing means 34 is for the lock plate 33 always locking engagement direction pressing energizing the (engagement piece 33a ₁ is oriented to engage the engaging teeth 31a ₁₎ is there. In the first embodiment, the lock urging means 34 is a tension coil spring whose both ends are hooked in holes at both ends of the upper portion of the front plate 32 and the upper portion of the main body portion 33 a of the lock plate 33. The strength required for the lock urging means 34 is determined by the relationship between the position, angle and vector of the engagement tooth surface 31a ₄ and the engagement piece 33a ₁ (lock plate 33), and the relationship is shown in FIGS. Will be described later. The form of the lock urging means 34 is not particularly limited.

(5) unlocking means unlocking means 35 has a used to temporarily disengage the teeth 31a ₁ and the engaging piece 33a _1. In the first embodiment, the unlocking means 35 is of the type with a button constituted by the unlocking bar 35a and the unlocking bar urging means 35b. The base end portion of the lock release bar 35a, and the lock release button 35a ₁ is provided to be operated from the outside of the headrest, the distal end portion of the lock release bar 35 is provided with inclined cam 35a _2. Unlocking bar 35a is supported in a slidable state in and out with respect to the resin cover 36, the lock release button 35a ₁ is pushed inward, locking the inclined cam 35a ₂ lock plate 33 release the bar equivalent by abutting the contact portion 33b _1, the unlocking direction the lock plate 33 is adapted to rotate the (engagement piece 33a ₁ is oriented away from the engaging teeth 31a _1). The unlocking bar urging means 35b is a member for urging the unlocking bar 35a outward. In the first embodiment, a compression coil spring is employed.

(6) Resin Cover The resin cover 36 is a member for covering the internal mechanism in the headrest tilting device 30, and is a left-right split type composed of a left resin cover 36a and a right resin cover 36b. ing. The resin cover 36 is usually a resin injection-molded product. The left resin cover 36a or the right resin cover 36b, the through-holes 36a ₁ penetrating in the right and left is provided in the through-holes 36a _1, unlocking bar guide support 36d for guiding and supporting the lock release bar 35a Can be inserted and supported. Further, on the inner surface of the left side resin cover 36a and right resin cover 36b, the engaging claws 36e for engaging the resin cover engagement hole 32 b ₁ of the front plate 32 is provided. Further, the lower surface portion of the resin cover 36 is a lower resin cover 36c that can be separated from the left resin cover 36a and the right resin cover 36b. The lower resin cover 36c, the stay insertion hole 36c ₁ pair of left and right for inserting a pair of left and right pipes in the headrest stay 10, for more firmly integrally coupled to the left resin cover 36a and the right resin cover 36b engagement claws 36c ₂ is provided, thereby suppressing rattling of the entire resin cover 36.

(7) Backward turning biasing means (front plate biasing means)
The backward rotation urging means 37 is a means for always urging the front plate 32 rearward (on the ratchet plate 31 side). This is for suppressing rattling of the headrest tilting device 30 due to vibration. 1 employs a torsion spring, the form thereof is not particularly limited as long as the front plate 32 can be urged rearward.

(8) Relationship between the position of the rotation center of the headrest frame and the lock plate 33 and the engagement point of the engagement teeth and engagement pieces and the vector (component force) FIG. 5 shows the tilting device 30 for headrest according to the first embodiment. is a diagram illustrating the relationship between the position and the vector of the rotation center _P 1, _{P 2} and the engaging teeth 31a ₁ and the engagement point _{P 3} of the engagement piece 33a ₁ of the headrest frame 20 and the lock plate 33 (the force component) . In the headrest of the first exemplary embodiment, as shown in FIG. 2, when viewed headrest from the side, the rotation center of the headrest frame 20 and P _1, and the center of rotation of the lock plate 33 and P _2, in the case of the point of engagement with the engagement piece 33a ₁ and teeth 31a ₁ was _{P 3,} the magnitude of the angle formed between the line segment _P 1 _{P 2} and line segment _P 2 _{P 3} theta is 90 ° or more I am doing so. Because, when the theta 90 ° or more, although the state shown in FIG. 5 (a), in this case, when a load is applied in the rearward direction of the headrest, the engagement piece 33a ₁ is engaged While a vector (component force) works in the direction of biting into the artificial tooth 31a ₁ , when θ is less than 90 °, the state shown in FIG. 5B is obtained. This is because a vector (component force) acts in a direction in which the engagement piece 33a ₁ is disengaged from the engagement teeth 31a ₁ when a load is applied to the engagement teeth 31a ₁ .

(9) Relationship Figure 6 engaging flank and the engagement piece contact angle and vector (component force) of the (lock plate) has a engaging flank 31a ₄ in the head rest tilting device 30 of the first embodiment it is a diagram illustrating the relationship between the contact angle and the vector (component force) of the engagement piece 33a _1. In the headrest of the first embodiment, as shown in FIG. 2, the magnitude γ of the contact angle of the engagement piece 33a ₁ with respect to the engagement teeth 31a ₁ when the headrest is viewed from the side is 90 ° or more. It is trying to become. Because, when the 90 ° or more gamma, although the state shown in FIG. 6 (a), in this case, when a load is applied in the rearward direction of the headrest, the engagement piece 33a ₁ is engaged A vector (component force) works in the direction of biting into the artificial tooth 31a ₁ , whereas if γ is less than 90 °, the state shown in FIG. 6B is obtained. This is because a vector (component force) acts in a direction in which the engagement piece 33a ₁ is disengaged from the engagement teeth 31a ₁ when a load is applied to the engagement teeth 31a ₁ . The set values related to the angles θ and γ described in the above (8) and (9) are influenced by the strength of the spring, the friction angle by the friction coefficient of the engagement teeth 31a ₁ and the engagement pieces 33a ₁ , and the like. It is moderated.

1.2 Operation of Headrest FIG. 7 is a diagram illustrating an adjustment operation of the headrest tilting device 30 according to the first embodiment. In this headrest, as shown in FIG. 7 (a), shown from that engagement teeth 31a ₁ of the engagement piece 33a ₁ of the lock plate 33 is engaged is located at the rearmost, in FIG. 7 (b) In this way, by switching to the front one step by step, it is possible to switch to the frontmost one as shown in FIG. 7C. In the state of FIG. 7A, the headrest is at the rear limit position, and in the state of FIG. 7C, the headrest is at the front limit position. Transition from the state of FIG. 7A to the state of FIG. 7C is made only by applying a forward force to the headrest. However, the headrest is so even when it reaches the forward limit position (the state of FIG. 7 (c)), the engagement between the engaging teeth 31a ₁ and the engagement piece 33a ₁ (lock) is not released ing. On the other hand, when the headrest is moved backward, by operating the lock release button 35a ₁ (FIG. 3), as shown in FIG. 7D, the engagement teeth 31a ₁ and the engagement pieces 33a ₁ Release the engagement (lock).

2. Next, the headrest of the second embodiment will be described. FIG. 8 is a diagram for explaining the operation of the headrest tilting device 30 according to the second embodiment. FIG. 9 is a cross-sectional view of the headrest of the second embodiment cut along a plane perpendicular to the left-right direction, and is an example of use as a swing structure.

Moreover, in the headrest of the first embodiment, the unlocking means 35 is of a type with a button, whereas in the headrest of the second embodiment, the unlocking means 35 is of a type without a button. That is, as shown in FIGS. 8 and 9, the unlocking means 35 is slidable on the switching pin 35c fixed to the ratchet plate 31, the guide bar 35d integrally coupled to the front plate 32, and the guide bar 35d. It is comprised with the resin piece 35e inserted in the state. Resin piece 35e is provided with a switching contact piece 35e ₂ and (switching contact piece A) switching the contact piece 35e ₃ (switching contact piece B) and the switching cam 35e _1, the lock plate 33, switching The cam contact portion 33b ₂ is provided. In the locked state of the head rest tilting device 30, the switching contact piece 35e ₂ is in a free state without restriction relative to the switching pin 35c, when adjusting the forward direction (pressed by hand), the resin piece 35e guide bar 35d and motion integrally, the contact piece 35e ₃ exchange該切at the forwardmost adjusted position contacts the switch pin 35c, beyond the most forward adjustment position, when further operated forward, the resin piece 35e is a guide bar 35d slide, switching cam 35e ₁ is in contact with the switching cam contact portion 33b ₂ equivalents, by rotating movement of the lock plate 33, disconnect the engagement to release the lock. When the pressed hand is released, it is returned to the rearmost adjustment position by the backward rotation biasing spring 37, and the resin piece 35e slides to return to the original state.

  In the headrest tilting device 30 according to the second embodiment, a ratchet hole and an engagement piece constituting a ratchet mechanism are provided in a pair on the left and right sides, and a load (force) is received on both left and right end surfaces, thereby enabling the use of a plate steel plate. Since the ratchet plate with the ratchet hole and the lock plate with the engagement piece can be made thin, fine pitch adjustment is possible, and the switching means does not use an overpass spring that changes in the release direction. Since the spring is biased in the locking direction, there is no problem with the malfunction of the spring. However, since there is an unintended movement, it is preferable to adopt the rear seat by the swing-down type.

DESCRIPTION OF SYMBOLS 10 Headrest stay 20 Headrest frame 30 Headrest tilting device 31 Ratchet plate 31a Vertical wall part 31a ₁ Engagement tooth 31a ₂ Ratchet hole 31a ₃ Fall-off prevention protrusion 31a ₄ Engagement tooth surface 31b Rear wall part 32 Front plate 32a Front wall part 32a ₁ Rear wall portion 32b Protruding wall portion 32b ₁ Resin cover engagement hole 33 Lock plate 33a Main body portion 33a ₁ Engagement piece 33b Folding portion 33b ₁ Lock release bar contact portion 33b ₂ Switching cam contact portion 34 Lock urging means 35 Unlocking means 35a Unlocking bar 35a ₁ Unlocking button 35a ₂ Inclined cam 35b Unlocking bar urging means 35c Switching pin 35d Guide bar 35e Resin piece 35e ₁ Switching cam 35e ₂ Switching contact piece A
35e ₃ switching contact piece B
36 resin cover 36a left resin cover 36a ₁ through hole 36b right resin cover 36c lower resin cover 36c ₁ stay insertion hole 36c ₂ engagement claw 36d lock release bar guide support part 36e engagement claw 37 rear rotation biasing means (front Plate biasing means)
40 skin 50 cushion material 101 pin 102 pin P ₁ rotation center of headrest frame P ₂ rotation center of lock plate P ₃ engagement point between engagement piece and engagement tooth P ₄ head load input section

Claims (9)

A headrest tilting device that makes it possible to adjust the tilting position of the headrest forward by supporting the headrest frame in a rotatable state with respect to the headrest stay,
A ratchet plate comprising a pair of left and right vertical wall portions formed with ratchet holes having a plurality of engaging teeth in a part of the inner peripheral portion thereof, and integrally coupled to the headrest stay;
A front plate integrally coupled to the headrest frame;
Front plate urging means for urging the front plate to rotate backwards;
A pair of left and right engaging pieces for engaging with the engaging teeth are provided to protrude outward from the left and right side edges, and are supported in a rotatable state with respect to the front plate. A lock plate that has a length up to 10 times the tilt angle pitch of the engaging teeth and rotates at a rotation angle of 15 ° or less,
Lock urging means for constantly urging the lock plate in the locking direction;
Unlocking means for temporarily releasing the engagement between the engagement teeth and the engagement pieces by rotating a lock plate in the unlocking direction;
A resin cover covering a member group consisting of a ratchet plate, a front plate, a front plate urging means, a lock plate, a lock urging means, and a lock releasing means ;
A tilting device for a headrest characterized by comprising: When viewed headrest from the side, the rotation center of the headrest frame and P _1, the rotation center of the lock plate and P _2, the point of engagement with the engagement tooth and the engaging piece and the P ₃ The tilting device for a headrest according to claim 1, wherein an angle θ formed by the line segment P ₁ P ₂ and the line segment P ₂ P ₃ is 90 to 110 °. The plurality of engaging teeth are formed in the upper section in the inner peripheral portion of the ratchet hole, and the lower front section in the inner peripheral portion is used as a front stopper portion,
The upward end surface of the engagement piece is a rear rotation restricting engagement portion that engages the engagement teeth from below and restricts the backward rotation of the headrest, and the downward end surface of the engagement piece is the front side It is a forward rotation restricting contact portion that contacts the stopper portion from above and restricts the forward rotation of the headrest,
The tilting device for a headrest according to claim 1 or 2, wherein a drop prevention protrusion is provided on a top portion of the engaging tooth and abuts against a downward end surface of the engaging piece engaged with the engaging tooth.   The tilting device for a headrest according to any one of claims 1 to 3, wherein the ratchet plate is made of a steel plate, and the ratchet hole is a punched hole left in a state where the periphery of the ratchet hole is connected. The unlocking means is
A lock release button that is operated from the outside of the headrest is provided, and a tilt cam is provided at the tip thereof, and when the lock release button is pushed in, the tilt cam comes into contact with the lock release bar contact portion of the lock plate An unlock bar for rotating the lock plate in the unlock direction,
Unlocking bar biasing means for biasing the unlocking bar outward;
The tilting device for a headrest according to any one of claims 1 to 4, comprising: The unlocking means is
A switching pin fixed to the ratchet plate;
A guide bar integrally coupled to the front plate;
A resin piece inserted slidably into the guide bar;
Consists of
The resin piece includes a switching contact piece A, a switching contact piece B, and a switching cam,
The lock plate has a switching cam contact portion;
In the locked state, while the switching contact piece A is in a free state without restriction with respect to the switching pin,
When a forward external force is applied to the headrest, the resin piece moves integrally with the guide bar, and the switching contact piece B contacts the switching pin at the foremost adjustment position.
When the headrest is operated further forward beyond the foremost adjustment position, the resin piece slides on the guide bar, the switching cam contacts the switching cam contact portion, and the lock plate rotates to move the engagement plate. Is unlocked and unlocked,
The headrest according to any one of claims 1 to 3, wherein when the external force is no longer applied to the headrest, the headrest is returned to the rearmost adjustment position by a backward rotation biasing spring, and the resin piece slides back to the original state. Tilting device. The headrest tilting device according to claim 6, which is coupled to the headrest stay and the headrest frame;
An epidermis covering the resin cover with the headrest frame;
Cushion material made of foamed resin,
With
The resin cover has a left-side resin cover and a right-side resin cover for covering the member group in the headrest tilting device from the left and right sides, and a lock for guiding and supporting the lock release bar on either of them. A headrest provided with a release bar guide support portion.   A resin cover engagement hole is provided in the front plate, and the resin cover is fixed to the front plate by engaging an engagement claw provided inside the resin cover with the resin cover engagement hole. 7. The headrest according to 7. The lower surface part of the resin cover is a lower resin cover that can be separated from other parts of the resin cover,
The headrest according to claim 7 or 8, wherein an engagement claw for integrally coupling the left resin cover and the right resin cover to the lower resin cover is provided.

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