HEADREST FOR SEAT

Abstract: A headrest for a seat of such a structure that only an upper central part of the seat back is tilted forward to be usable as a headrest and the headrest can be automatically returned to the initial position when tilted forward at an angle larger than a predetermined one with respect to the seat back. The headrest (7) comes outward from or goes inward to the step-like recess (6) formed on the upper part of the seat back (1) and is swingably supported through a hinge mechanism (8) provided with a ratchet mechanism (14). The hinge mechanism (8) comprises: a movable part (11) to be fixed to the lower part of a support frame (7a) of the headrest (7); a hinge proper (10), which is fixed to the seat back frame (1a), and pivotally fixed with a turning shaft (12); and a return spring (18) provided to the support frame (7a) of said headrest (7). Thus, the headrest (7) is returned to the position for standing upright. The ratchet mechanism (14) is constructed so that a ratchet tooth (15) may disengage from a ratchet pawl (18) when the headrest (7) is tilted forward at an angle larger than a predetermined one. The headrest (7) is returned to the initial position by tension of said return spring (18).

Description: TECHNICAL FIELD The present invention relates to a passenger seat with a headrest, the seat is used for airplanes, ships, rail road vehicles and so on, which is capable of tilting forward its supporting surface for supporting a rear head region of a person seated on a seat within a predetermined angle range. BACKGROUND ART Conventionally, there has been known a seat (EP 024 687 A2) used for airplanes, ships, rail road vehicles and so on which consists of a seat back 51 having a top portion equipped with a headrest 52 hingedly supported on a hinge point 53 so as to be tiltable forward with respect to the seat back 51. However, in the above conventional case, all of the headrest 52 is constituted to be tiltable forward with respect to the seat back 51 by being tilted about the hinge point 53. Therefore, in the case where some passengers walk an aisle in an airplane by holding the headrests 52 which are tilted forward, there is a problem such that the headrests 52 move unintentionally and causes a passenger seated on the seat trouble. The present invention has been done in view of above problems and disadvantages encountered in the prior art, and has an object to provide a headrest for seats which does not cause problems or trouble to a passenger sitting on that seat when an other person is holding itself on the headrest. DISCLOSURE OF INVENTION In accordance with the present invention the above object is solved with a passenger seat having the features of claim 1. With above arrangement, it becomes possible to adjust an angle of the headrest stepwisely when the seat back is tilted forward. Therefore, since the headrest supports a rear head region of a person seated on a seat perfectly, it becomes possible to prevent a neck region and an abdominal region from being tired so much. Especially, the headrest is constituted so as to tilt forward and rearward in the recessed portion formed on the upper portion of the seat corresponding to a rear head region of a passenger through the hinge mechanism. Therefore, even if a passenger walking an aisle in an airplane holds an upper portion of a seat unexpectedly, his or her hand is prevented from directly touching the headrest. Therefore, the headrest is not unexpectedly moved and, thus, it is surely avoided to cause the person seated on the seat trouble. Moreover, if the tilted headrest is further tilted down to the lowest end, it can be easily and accurately returned to the original position by the pulling force of the return spring equipped in the hinge mechanism. Therefore, it becomes possible to promptly and easily clean up a passenger room of an airplane or a passenger car of a train at a terminal station. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a perspective view of a seat showing an embodiment of a headrest for seats; Fig. 2 is a cross-sectional side view showing a seat back under the condition where its headrest portion is tilted forward; Fig. 3 is a cross-sectional side view showing a seat back under the condition where its headrest portion is retracted in its original portion; Fig. 4 is a side view showing a hinge mechanism; Fig. 5 is a front view showing the hinge mechanism; Fig. 6 is a side view partly broken away to show a rachet mechanism; Fig. 7 is a side view partly broken away to show the rachet mechanism; and Fig. 8 is a perspective view showing a seat equipped with a conventional headrest. BEST MODE FOR CARRYING OUT THE INVENTION Now referring to the accompany drawings, an embodiment of the headrest for seats in accordance with the present invention is explained. Fig. 1 shows a seat for an airplane including a headrest in accordance with the present invention. In the drawing, a reference numeral 1 denotes a seat back which is hingedly supported on a rear end of the seat bottom 2 through a reclining mechanism (not shown) having a hinge point on the rear end of the seat bottom, so as to be reclined rearward. There are fixedly provided a pair of armrests 3, 3 at both sides of the seat bottom 2. And, ashtray 4 etc. are provided at a front end of the armrest 3. Further, a seat belt 5 is equipped between these armrests 3, 3. Figs. 2 and 3 show a headrest in accordance with the present invention. There is provided a recessed portion 6 of substantially rectangular shape on an upper portion of the seat back 1, at a location corresponding to a rear head region of a passenger seated on the seat. A headrest 7 has substantially the rectangular shape so as to be retracted in the recessed portion 6, and has a supporting frame 7a therein. A lower portion of the supporting frame 7a is fixed on a frame 1a of the seat back 1 through a hinge mechanism 8 by means of a screw etc. A reference numeral 13 denotes a headrest cover which covers the upper portion of the seat back 1. This headrest cover 13 serves to conceal a gap occurring between the seat back 1 and the headrest 7 when the headrest 7 is tilted forward. Therefore, not only extraneous substances can be prevented from entering into the gap but an appearance of the headrest 7 can be nicely maintained. Figs. 4 through 7 show a hinge mechanism and a rachet mechanism. This hinge mechanism 8 consists of a hinge main body 10 and a movable hinge portion 11. The movable hinge portion 11 is supported on the hinge main body 10 through a rotational shaft 12 so as to be swingable about the rotational shaft 12. The hinge main body 10 of the hinge mechanism 8 is fixed on the frame 1a of the seat back 1 by means of a screw 9 and so on. And, the movable hinge portion 11 is fixed on the supporting frame 7a of the headrest 7 by means of a screw 9 and so on. Furthermore, the rotational shaft 12 serves as a hinge point P, and is installed on the seat back 1 such that its height becomes substantially equal to a height of a neck region of a seated person. At a shaft portion 12 of the hinge mechanism 8, there is provided a rachet mechanism 14 for easing the headrest tilting forward as shown in Figs. 6 and 7. This rachet mechanism 14 includes a rachet gear 15 formed on the movable hinge portion 15 and a rachet claw member 16 meshing with this rachet gear 15. A base end of the rachet claw member 16 is hingedly supported on the hinge main body 10. And, a distal end 16a of the rachet claw member 16 is urged to engage with the cachet gear 15 by a spring 17 provided on the hinge main body 10. A gear portion of the rachet gear 15 is formed in such a configuration that it allows the rachet gear 15 to rotate in only one direction (i.e. a direction of an arrow A), so that the headrest 7 can rotate synchronously in only one direction of the arrow A. Therefore, even if the headrest 7 is applied a force acting in opposite direction of the arrow A, the rachet gear 15 firmly meshes with the rachet claw member 16 so as to resist such a reverse rotation. Accordingly, if the headrest 7 is applied a force acting in its rotational direction (i.e. the direction of the arrow A), it becomes possible to change the inclined angle of the headrest as much as desired so as to fit to a head region of a person seated on the seat. Thus, it brings comfort to a seated person. That is, the headrest 7 can be used preferably. In this embodiment, the rachet gear 15 has four teeth so that the headrest 7 can be adjusted at four different tilt angles, as shown in Fig. 4. Especially, in accordance with the present invention, the rachet mechanism 14 is constituted in such a manner that not only the rachet claw member 16 meshes with the rachet gear 15 so that the movable hinge portion 11 is allowed to swing in only one direction with respect to the hinge main body 10 but a cam plate 19 releases the engagement between the rachet claw member 16 and the rachet gear 15. Therefore, if the headrest 7 tilts forward beyond a predetermined angle, the rachet gear 15 is disengaged from the rachet claw member 16 and the headrest 7 is returned to its original position (i.e. a raised position) by means of a pulling force of a return spring 18. Moreover, it is needless to say that the same effect can be obtained even if the hinge main body 10 is fixed on the supporting frame 7a of the headrest 7 and the movable hinge portion 11 is fixed on the seat back frame 1a. Next, a method for using the headrest for seats in accordance with the present invention will be explained. A seated person can tilt the headrest 7 at a desired angle by slightly pushing the upper portion 7b of the headrest 7 forward so that the headrest 7 can tilt forward about the rotational shaft 12 of the hinge mechanism 11 as a hinge point P of fixed on the supporting frame 7a of the headrest 7. Then, if the headrest 7 is further slightly tilted forward, the rachet claw member 16 of the rachet mechanism 14 meshes with the rachet gear 15. Thus, the headrest 7 can be adjusted at several different angles corresponding to the number of the teeth of the rachet gear 15 to hold a forward tilting at a determined angle. To the contrary, if the headrest 7 is tilted down to the lowest end, the rachet claw member 16 of the rachet mechanism 14 is disengaged from the rachet gear 15, and the headrest 7 is returned to its original position (the raised position) by the pulling force of the return spring 18. INDUSTRIAL APPLICABILITY As is explained in the foregoing description, the headrest for seats in accordance with the present invention is useful for the headrest for various seats used in airplanes, ships, rail road vehicles and so on. Especially, it is suitable for seats that are required to be capable of easily and promptly returning their headrests from their tilted positions to their original positions, for example, in the case where a passenger room of an airplane is cleaned up or a passenger car of a train is cleaned up at a terminal station.

Claims: Passenger seat with a headrest (7) this seat having a seat back (1) with the headrest (7) hingedly fixed on in a position corresponding to the position of a rear head region of a person sitting on the seat, the headrest is swingably supported by means of a hinge mechanism (8) equipped with a ratchet mechanism (14), said hinge mechanism (8) including a movable hinge portion (11) fixed on a lower portion of a supporting frame (7a) of the headrest (7), a hinge main body (10) fixed on a seat back frame (1a) so as to be hingedly supported on a rotational shaft (12) together with the movable hinge portion (11), and a return spring (18) to return the supporting frame (7a) of the headrest (7) to its raised position, said ratchet mechanism (14) being constituted in such a manner that, when the headrest (7) is tilted forward beyond a predetermined angle, a ratchet gear (15) is disengaged from a ratchet claw member (16) so that the headrest (7) can be returned to the original position by the pulling force of said return spring (18), characterized in that the seat back (1) has a recessed portion (6) on its upper end and that the headrest (7) is inserted integrally in this recessed portion (6) and that the mechanism (19) for disengaging the ratchet gear (15) and the ratchet claw member (16) are mounted on the rotational shaft (12) for the headrest (7). Seat according to claim 1, characterized in that the return spring (18) is a coil spring mounted on the rotational shaft (12).

Inventors: KURANAMI SHUNJI, KURANAMI, SHUNJI
Applicants: KOITO KOGYO KK, KOITO INDUSTRIES, LTD.
Application year: 1991
Main classification: A47C7
IPC codes: B60N2, A47C7, B64D11