Abstract:
A passenger seat with built-in speakers having a headrest and a pair of flaps located adjacent the headrest. The flaps are freely movable with respect to the headrest and provided with built-in speakers. The passenger seat with built-in speakers has a detector which detects a predetermined anglular position of the flap with respect to the headrest.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an audio system which has built-in speakers provided for a passenger seat in a transportation means such as aircraft, railway passenger car and motor vehicle. 
     2. Description of the Related Art 
     Various audio systems have been proposed, each of which has built-in speakers provided for a passenger seat in a transportation means such as aircraft, railway passenger car and motor vehicle. FIG. 1 shows an example of such audio systems disclosed in Japan UM Kokai No.5-63358 wherein the system has a pair of speakers  6  and  6 ′ provided in a passenger seat of a railway passenger car. The passenger seat includes a seat  1 , a backrest  2 , armrests  3 , a central headrest  4  and a pair of side headrests  5 . The audio system includes built-in speakers  6  and  6 ′ which are respectively provided within the side headsets  5 . When the audio system is not in use, the side headrests  5  are positioned in line with the central headrest  4  so that the speakers  6  are covered by the the side surfaces of the central headrest  4 . When the side headrests  5  are pulled forward to be tilted around pivot parts  7  by the user, the speakers  6  are positioned so as to cover the user&#39;s ears. With the side headrests  5  being partly pulled forward from the central headrest  4  so as to expose half of the speakers  6 , for example, the sound volume from the speakers  6  can be adjusted without the operation of the volume control of the control panel. 
     In the above audio system, however, the listener has to pull the side headrest  5  forward to a predetermined position before turning ON a power source. Moreover, when the listener finishes listening to the music program, he has to turn OFF the power source and push back the side headrest  5  to the original position, which is a cumbersome task. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     The invention has been made in view of the above problem, and it is an object of the invention to provide an audio system which is simple to use. 
     To attain the above object, according to the first aspect of the invention, there is provided a passenger seat having a headrest and a pair of flaps located adjacent sides of the headrest, the pair of flaps being movable with respect to the headrest and speakers provided in the flaps comprising detection means for detecting a predetermined anglular position of the flaps with respect to the headrest. 
     According to the second aspect of the invention, there is provided a passenger seat with built-in speakers as claimed in claim 1 wherein the detection means comprises a detecting member which moves according to movement of the pair of flaps and a sensor which detects an anglular predetermined position of the detecting member. 
     According to the third aspect of the invention, there is provided a passenger seat with built-in speakers as claimed in claim 2 wherein the sensor is a mechanical switch which operates when the detecting member moves to the predetermined anglular position so as to contact the sensor. 
     According to the fourth aspect of the invention, there is provided a passenger seat with built-in speakers as claimed in claim 1 further comprising a linkage member connecting the flaps and the detecting means detects the predetermined anglular position of one of the flaps. 
     According to the fifth aspect of the invention, there is provided an audio system comprising a passenger seat with built-in speakers comprising a supplying means providing acoustic power to the speakers when the detection means detects that the flaps are in the predetermined angular position. 
    
    
     BRIEF EXPLANATION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a prior art of an audio system with speakers built into a passenger seat of a railway passenger car; 
     FIG. 2 is a perspective view of the headrest and its side flaps of the passenger seat with built-in speakers according to the present invention; 
     FIG. 3A is a schematic plan view showing the structure of the headrest and its side flaps of the passenger seat with built-in speakers according to the present invention; 
     FIG. 3B is a segmentary view showing the end portion of the L-shaped arm which secures the side flaps to the headrest; 
     FIG. 3C is a segmentary view showing the end portion of the L-shaped arm in the unused position; 
     FIG. 4 is a schematic plan view showing another embodiment of the passenger seat with built-in speakers according to the present invention; 
     FIG. 5 is a block diagram showing an audio system according to the present invention; and 
     FIG. 6 is a flow chart which shows the operation of the the passenger seat with built-in speakers and the audio system therefor according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments of the passenger seat with built-in speakers and the audio system therefor according to the invention will be explained in the following with reference to the drawings. 
     FIG. 2 is a perspective view showing a main part of a passenger seat with built-in speakers  10  according to the invention. The passenger seat  10  with built-in speakers is exemplified as a two-seater seat having two headrests  11  disposed adjacently to each other. On both of the right and left sides of the headrest  11 , there is provided a pair of movable side headrests or side flaps  12 . A speaker  13  is provided in each of the side flaps  12 . Each of the side flaps  12  is configured such that it is movable from a position in which it is disposed in line with the headrest  11  to a position in which the side flaps  12  are disposed approximately perpendicular to the headrest  11  for the user to listen to a music program. 
     In detail, as shown in FIG. 3A, each of the side flaps  12  on the right and left sides constituting the passenger seat with built-in speakers  10  is coupled to the headrest  11  by a pair of L-shaped arms  14 . The L-shaped arm  14  is secured to the side flap  12  with a securing pin  15  at one end and is pivotally secured to the headrest  11  with a supporting pin  16  at the other end so as to be rotatable. This allows each side flap  12  to turn about 90° from an unused position in which the side flap  12  is disposed in line with the headrest  11  to a used position in which the side flap  12  is disposed to be approximately perpendicular to the headrest  11 . A pair of the L-shaped arms  14  secured to the side flaps  12  on the right and left sides of the headrest  11 , respectively, are linked to each other in the headrest  11  with a linking arm which is not shown. Therefore, with one of the side flaps  12  turned from the unused position to the used position, for example, the other side flap  12  is turned in the same manner as the former one by the linking arm. That is, the side flaps  12  are pivotally secured to the headrest  11  to move symmetriacally with respect to the central portion(the position for supporting the user&#39;s head) of the headrest  11 . 
     A protrusion  18  is formed on the headrest  11  side end of the L-shaped arms  14  for turning ON and OFF a mechanical switch  17 . The mechanical switch  17  is provided as detection means for detecting that each of the side flaps, i.e. the speakers  13  is positioned at a predetermined position with respect to the headrest  11 . With the side flap  12  in the used position, the protrusion  18  on the L-shaped arm  14  presses the mechanical switch  17  to “ON” as shown in FIG.  3 B. While, with the side flap  12  swiveleded from the used position to the unused position, the protrusion  18  on the L-shaped arm  14  is detached from the mechanical switch  17  to turn it “OFF” as shown in FIG.  3 C. When the listener sitting on the passenger seat with built-in speakers  10  moves the side flaps  12  from the unused position to the used position (the position in which the side flaps  12  cover both ears of the listener) with the listener&#39;s head supported on the headrest  11 , the mechanical switch  17  is turned ON. With the mechanical switch  17  turned ON, music is provided from the right and left speakers  13  connected to an audio system  30  to be described later. 
     In another embodiment, the passenger seat  10  with built-in speakers may be constituted so that the side flaps  12  move back and forth along respective sides of the headrest  11  as shown in FIG.  4 . In the embodiment, the L-shaped arm  14  is pivotally secured to the side flap  12  with a holding pin  19  at one end thereof so as to be rotatable, and is pivotally secured to the headrest  11  with a supporting pin  16  at the other end so as to be rotatable. This allows the side flaps  12  to be movable back and forth along the respective sides of the headrest  11 . A pair of the L-shaped arms  14  pivotally secured to the side flaps  12  on the right and left sides of the headrest  11 , respectively, are linked to each other in the headrest  11  with a linking arm so that with one of the side flaps  12  moved, the other flap  12  is moved in the same manner as the former one by the linking arm. 
     Next, the configuration of audio system  30  of the invention will be explained with reference to a block diagram shown in FIG.  5 . 
     The audio system  30  includes an audio signal source  20  such as a compact disk (CD) or a receiver, a fader  21  which gradually increases or decreases the signal output from the audio signal source  20 , an amplifier  22  which amplifies the signal outputted from the audio signal source  20 , a control panel  23  which is used for sound volume adjustment and for selecting an audio signal source such as a played back CD, and a controller  24  which controls the audio system  30 . A detection signal supplied from the mechanical switch  17  inside the headrest  11  is provided to the controller  24 . The signal emitted from controller  24  is provided to amplifier  21  which is connected to the speakers  13  provided in the respective side flaps  12 . 
     Operation of the passenger seat with built-in speakers  10  and the audio system  30  therefor according to the invention will be explained with reference to the flow chart shown in FIG.  6 . 
     When the user sits in seat  10  with his head supported on the headrest  11  and moves the side flaps  12  from the unused position to the used position, the mechanical switch  17  is turned on to actuate the audio system  30 ,i.e., the aoudio signal power is supplied to the speaker  13  via the fader  21  and the amplifier  22 . 
     Then, in step S 1 , the controller  24  monitors whether or not the detection signal is supplied from the mechanical switch  17 . When detection signal is not supplied from the mechanical switch  17  (NO), monitoring is terminated. The controller  24  performs this monitoring at a predetermined cycle (2 seconds, for example). When the controller  24  receives a signal indicating that the mechanical switch  17  is turned ON (YES), then a fade-in operation is carried out in step S 2 . 
     The audio system  30  is configured to always provide a music program from the audio signal source  20  selected by the user so that when the fader  21  is turned ON to carryout a fade-in operation, the selected music program is performed through speakers  13  with the volume gradually being increased. The fader  21  increases the sound volume to a level predetermined by the user. 
     In step S 3 , the controller  24  monitors whether or not an off signal is supplied from the mechanical switch  17 . When the OFF signal is supplied from the mechanical switch  17  (YES), then the fader  21  operates to carry out a fade-out operation to gradually decrease the sound volume. The operation is then terminated. When an off signal is not supplied (NO), controller  24  further determines whether or not the control panel  23  is operated by the user in step S 4 . 
     In step S 4 , when the control panel  23  is not operated (NO), then the operation in step S 3  is performed. When the user operates the control panel  23  (YES), then the music program of the audio signal source  20  is changed or the sound level is adjusted in accordance with the setting of the control panel  23  reflecting the user&#39;s operation, in step S 5 . Thereafter the operation in step S 3  is performed. 
     While the audio system  30  is in use, the controller  24  always monitors a signal from the mechanical switch  17  or the control panel  23  to comply with the user&#39;s demand. 
     The user may provide the audio signal source  20  with a CD changer that randomly reproduces various music programs or with a plurality of CD changers each with a different music category the selection of which is left to the user. The user may carry out the opearation by operating the control panel  23 . The content of operation such as selection of the music category or volume adjustment may be stored in the RAM(not showm) of the controller  24 . This allows the user to listen to the music with the volume preset in the RAM without operatiing the control panel  23 . When a visual display is provided in addition to the audio program, the system may be configured so as to turn on and off the monitor display in accordance with the on/off of the mechanical switch  17 . 
     According to the invention, with the user sitting in the passenger seat  10  provided with built-in speakers and moving one of the side flaps  12  from the unused position, both of the side flaps  12  on the right and left are moved together to the positions for covering the user&#39;s ears. This turns the mechanical switch  17  on to gradually increase the volume from both speakers  13  provided in the respective side flaps  12  until the user can enjoy a music program with a predetermined sound volume level. When the user does not care to listen to the music, the user moves one of the side flaps  12  backward, by which both of the side flaps  12  are moved backward together to uncover the user&#39;s ears while the sound level of the music fades out. Thus, the audio system is simple to handle, and does not interfere with the user sitting in the seat. 
     While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention.