Abstract:
A seating unit for a passenger vehicle, especially an aircraft, has a reclinable seat back connected to a seating portion by a hinge. A slider is mounted in a guide track and supports the hinge. A pivotally connected front strut supports the seating portion at a location in front of the hinge. A pivotally connected rear strut supports the seat back at a location spaced apart from the hinge. As the slider along the guide track, the seat back moves to an orientation substantially coplanar with the seating portion so as to provide a flat surface for a sleeping passenger.

Description:
FIELD 
     This invention relates to a seating unit for a passenger vehicle, especially an aircraft, comprising a seat having a base, a reclinable seat back, a seating portion, a hinge pivotally connecting the rear edge of the seating portion to the bottom edge of the seat back, and mounting means for supporting the seat back and seating portion on the base so that the seating portion moves forward as the seat back reclines. 
     RELATED ART 
     Seating units of this type are disclosed in GB-A-2331237 and EP-A-0869061. The seating portion moves forward with the reclining of the seat back so as to cooperate to form a substantially flat surface when the seat back is reclined in a substantially horizontal position. 
     SUMMARY OF THE INVENTION 
     According to the invention, in a seating unit of the type described above, the mounting means comprises a guide track mounted on the base, a slider mounted in the guide track and supporting the hinge between the seat back and the seating portion, a front strut pivotally connected at an upper end to a front portion of the base and pivotally connected at a lower end to the seating portion at a location in front of the hinge and a rear strut pivotally at one end to a rear portion of the base and pivotally connected at the other end to the seat back at a location spaced apart from the hinge, and drive means operative to cause movement of the slider along the guide track. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a first passenger seating unit for an aircraft cabin in its fully upright position; 
     FIG. 2 is a schematic side view of the seating unit shown in FIG. 1; 
     FIGS. 3 and 4 are views corresponding to FIGS. 1 and 2 but showing the first seating unit in a partly reclined position; 
     FIGS. 5 and 6 are views corresponding to FIGS. 1 and 2 but showing the first seating unit in a further reclined position; and 
     FIGS. 7 and 8 are views corresponding to FIGS. 1 and 2 but showing the first seating unit in its fully reclined position. 
     FIG. 9 is a schematic longitudinal sectional view of a second passenger seating unit for an aircraft cabin in its fully upright position; 
     FIG. 10 is a view corresponding to FIG. 9 but showing the second seating unit in a partly reclined position; 
     FIG. 11 is a view corresponding to FIG. 9 but showing the second seating unit in an angled flat-bed position; and 
     FIG. 12 is a view corresponding to FIG. 9 but showing the second seating unit in a “Z-bed” position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a seating unit for use in the passenger cabin of an aircraft comprises a base unit  10  incorporating two fixed armrest units  12  and  14 . The seating unit also has a seating portion  16 , a seat back  18  and a leg rest  20 . The bottom of the seat back  18  is connected to the rear of the seating portion  16  by a hinge  22  each end of which is mounted on a respective slider  24 , one of which engages in a guide track  26  mounted on the inside surface of the armrest unit  12 , and the other engages in a corresponding guide track (not shown) on the inside surface of the other armrest  14 . 
     The front end of the seating portion  16  is connected by a pivot pin  28  to one end of a front strut  30  of fixed length. The other end of the front strut  30  is connected by a pivot pin  32  to the base unit  10 . The leg rest  20  is pivotally mounted on the front edge of the seating portion  16  by a conventional mechanism  34  (see FIGS. 5 and 7) which will not be described in detail. 
     A telescopic rear strut  36  has its upper end connected by a pivot pin  38  to the seat back  18  at a location spaced from the hinge  22 . The lower end of the rear strut  36  is connected by a pivot pin  40  to the base unit  10 . The rear strut  36  includes an electrically powered drive unit  42  which can be actuated to vary its length. In FIGS. 1 and 2, when the seat back  18  is in its fully upright position, the rear strut  36  is at maximum length. 
     A static screen has side walls  50  extending rearwardly from the behind the armrest units  12  and  14  respectively, with their rear ends interconnected by an end wall  52 . A movable screen  54  has its bottom rear edge connected to the top edge of the end wall  52  by a hinge  56 . Quadrant-shaped side screens  58  are attached to the side edges of the movable screen  54 . When the seat back is in its upright position shown in FIGS. 1 and 2, the upper edge of the movable screen  54  is in close proximity to the rear surface of the seat back  18 . 
     A second (rear) telescopic strut  60  has its front end connected by a pivot pin  62  to the front strut  30  at a location spaced from the pivot pin  32 . The rear end of the second telescopic strut  60  is connected by a pivot axle  64  which extends between the armrest units  12  and  14 . The second telescopic strut  60  includes an electrically powered drive unit  66  which can be actuated to vary its length. In FIGS. 1 and 2, the second telescopic strut  60  is at minimum length. 
     When the seat back  18  is to be reclined, the drive unit  42  is actuated to shorten the telescopic rear strut  36  to its minimum length as shown in FIGS. 3 and 4. The movable screen  54  rides up the back surface of the seat back  18 . The seating portion  16  remains substantially in its original position. At the same time, the mechanism  34  may be arranged to start to move the leg rest  20  upwardly. 
     Next, the drive unit  66  is actuated to lengthen the second telescopic strut  60 , thereby causing the sliders  24  to start to move along the tracks  26  as illustrated in FIGS. 5 and 6. The resulting forward movement of the seating portion  16  causes the front strut  30  to pass through its vertical position. The movable screen  54  reaches a vertical position with upper edge level with the top of the seat back  18 . 
     When the second telescopic strut  60  reaches its maximum length, the seating portion  16  is in its fully forward position, as shown in FIGS. 7 and 8. This forward position moves the seating portion  16  forward and causes the seat back  18  to move to a substantially horizontal position. The resulting continued clockwise movement of the front strut  30  lowers the front edge of the seating portion  16  so that it forms a substantially flat surface with the seat back  18 . The leg rest  20  is also moved to a substantially horizontal position so as to form a continuation of this flat surface. The sliders  24  are now at the front end of the track  26 . The movable screen  54  remains vertical and, together with the side screens  58 , shields the head area of the seat back  18 . 
     The seating unit can be restored to its upright position by reversing the direction of operation of the drive units  42  and  60 . It will be noticed that, even when the seating unit is in its upright position, the movable screen  54  is at an angle of at least 44° to the horizontal. This discourages the placing of movable articles on the screen  54  and thus avoids any hazard from such articles being tipped on to the feet of a passenger occupying a seat behind the seating unit illustrated. 
     In the drawings, the base unit  10  is shown as comprising a flat floor panel. This may be replaced by a frame connecting the armrest units  12  and  14 , and the pivot pins  32  and  40  to the floor of the aircraft cabin. 
     FIGS. 9 to  12  show another seating unit  70  in accordance with the invention, together with the rear part of a seating unit  72  positioned in front of the seating unit  70 . Some detail has been omitted from FIG. 9 for the sake of clarity. Corresponding parts of the seating units  70  and  72  are denoted by the same reference numerals and will not be described in detail. As can be seen in FIGS. 9 and 10, each seating unit comprises a static portion having a back panel  74  and two side panels  76  (only one of which is visible in the drawings incorporating arm rests). Each back panel  74  has a recessed portion  78  for accommodating the lower legs and feet of the passenger occupying the seat behind. 
     The seating unit also has a seat portion  80 , a back rest  82  and a leg rest  84 . The bottom of the back rest  82  is connected to the rear of the seat portion  80  by a hinge  86  which has its ends secured to respective sliders  88  engaging in guide tracks  90  on the inside surface of each of the side panels  76 . A fixed-length rear strut  92  has one end pivotally connected by a pivot pin  94  to the back rest  82  at a location spaced from the hinge  86 . The lower end of the strut  92  is connected by a pivot pin  96  to a rear transverse member  98  extending between the side panels  76 . 
     A front support strut  100  has its upper end connected by a pivot pin  101  to a location on the seat portion  80  spaced forwardly from the hinge  86 . The lower end of the strut  100  is connected by a pivot pin  102  to one end of an L-shaped lifter link  104  which is supported at its mid-point on a pivot pin  106 . The pin  106  is mounted on a front transverse member  108  extending between the side panels  76 . The other end of the lifter link  104  is connected to a first screw jack drive  110  mounted between the side panels  76 . A second screw jack drive  112  is mounted between the side panels  76  and has its driven end connected by a pivot pin  114  to an intermediate location on the front support strut  100 . 
     The rear transverse member  98  and the front transverse member  108 , together with other structural elements (not shown, which may include the floor of the aircraft) form a base for the seat. 
     The leg rest  84  is connected to the seat portion  82  by a four-bar link mechanism comprising links  116  and  118  which are pivotally connected to the seat portion  80  and links  120  and  122  which are pivotally connected to the leg rest  84 . The link  118  is connected by a first intermediate pivot pin  124  to the link  120  and by a second intermediate pivot pin  126  to the link  122 . The link  120  is also connected by a third intermediate pivot pin  128  to the link  116 . The link  120  has an infill panel  130  rigidly mounted thereon for a purpose to be explained hereinafter. A third screw jack drive  132  is mounted on the front support strut  110  and has its driven end connected by a pivot pin  134  to an intermediate point on the link  118 . 
     When it is desired to move the seat from the upright position shown in FIG. 9 to an intermediate reclined position as shown in FIG. 10, the second screw jack drive  112  drives the front support strut  100  forwards so that the slider  88  starts to move along the guide track  90 . If it is desired to deploy the leg rest  84  at the same time, the third screw jack drive  132  pushes the link  118  forwards. 
     As shown in FIG. 11, continued forward movement of the screw jack drives  112  and  132  moves the slider  88  to the front of the slide track  90  and pushes the leg rest  84  forward to a maximum extent. In this condition, the back rest  82 , the seat portion  80  and the leg rest  84  are in line with one another and the infill panel  130  has swung up to fill the gap between the seat portion  80  and the leg rest  84 . This provides a flat surface on which a seat occupant can sleep, albeit one which is inclined at about 16° to the cabin floor. 
     Although the angle between the flat surface shown in FIG.  11  and the horizontal is only about 13° because aircraft commonly fly in a 3° nose-up attitude, some passengers may find this inclination uncomfortable. As an alternative, the first screw jack drive  110  may be actuated to drive the rear end of the lifter link  104  downwards so as to raise the front support strut  110  sufficiently for the top surface of the seat portion  80  to be parallel with the cabin floor, as shown in FIG.  12 . At the same time, the screw jack drive  132  is retracted so that the leg rest  84  is approximately parallel to but no longer coplanar with the seat back  82 . 
     It will be appreciated that, at all times, there is a minimum clearance between the various parts of the seat  70  and the back of the seat  72  in front as indicated by the chain-dotted line  140 . 
     If the seat is not required to take up the position shown in FIG. 12, the lifter link  104  and its screw jack drive  132  may be omitted and the pivot joint  102  being secured at a fixed location relative to the transverse member  108 . Similarly, if the position shown in FIG. 11 is not required, the pivot joint  102  may be secured at a fixed location chosen in relation to the length of the front strut  100  so that the seating portion is movable between the position shown in FIG.  9  and the position shown in FIG.  12 . 
     The leg rest  20  of FIGS. 1 to  8  may be mounted on a mechanism of the type shown in FIGS. 9 to  12 . Alternative mechanisms may be used for supporting the leg rest  84  provided that they keep it behind the line  140 .