Abstract:
A seat includes a first seat piece ( 10 ) and a further seat piece ( 12 ), which may be adjusted for inclination by a controllable operating device ( 14 ). The operating device ( 14 ) engages the further seat piece ( 12 ) by at least two adjusters ( 30 ), which are moved by a common drive mechanism ( 34 ) with a mechanical coupling ( 36 ) between the adjusters ( 30 ), for an effectively uniform motion. A uniform inclination adjustment of the further seat piece, such as backrest and/or leg rest is achieved. The drive includes an actuator device with a longitudinally displaceable operating piece ( 40 ), engaged with a rocker ( 44 ), connected to an adjuster piece ( 30 ) and operating the mechanical coupling ( 36 ), with a further rocker ( 46 ), for the other adjuster ( 30 ).

Description:
FIELD OF THE INVENTION 
   The present invention relates to a seat, in particular a vehicle seat, preferably an aeroplane seat, with a first seat part, and with another seat part which can be adjusted in tilt by a triggerable actuating means. The actuating means engages the other seat part with at least two adjustment parts which can be moved by a common drive. Uniform movement of the adjustment parts in this respect causes mechanical coupling between them. 
   BACKGROUND OF THE INVENTION 
   A pertinent aircraft passenger seat, described in DE 199 44 620, has individual seat components, including a leg rest and a backrest. These seat components can be moved by actuating means which can be triggered by a hand-operated actuating means for adjusting the seat to the requirements of the seat occupant. Hand levers for the seat parts are modeled to the contours of these seat parts as an element of the actuating means, and are combined in one operating part for adjusting the aircraft passenger seat for meaningful adjustment for the seat parts. 
   In all known tilt adjustment means for seat parts, such as a backrest or leg rest, depending on the actuating and tilt adjustment means used at the time, obstacles can arise since generally the actuating means engages only one point of the backrest and/or leg rest. This single point engagement leads to twisting or torsion of the other seat part to be adjusted in its tilt. Even with minor twisting or torsion, a uniform swivelling motion cannot be achieved with a good feeling of the body for the seat occupant. Also, depending on the adjustment structure being used, in case of a crash, unilateral loading of the actuating means, especially in the form of a servo-drive, occurs. The activating means are often not able to accommodate the forces which suddenly occur. 
   DE-A-33 35 486 A1 discloses a device for adjusting the height and the tilt of the backrest of the seat, especially of a motor vehicle seat. For selective adjustment of the tilt of a backrest or the height of the entire seat by a single drive spindle, the drive spindle has two spindle parts which each bear a mating non-rotatable bevel wheel to interact with a bevel wheel on the spindles of individual adjustment mechanisms. They are connected non-rotatably only in a certain relative axial position by way of gear rings. In this position, only one mating bevel wheel meshes with the assigned bevel wheel. In the other relative axial position of the two drive spindle parts, the two mating bevel wheels mesh with the assigned bevel wheels, but the non-rotatable connection between the two drive spindle parts is canceled. The known gear approach has a plurality of bevel wheels which fit into one another at a right angle so that the known approach takes up a relatively large amount of construction space on the respective vehicle seat and is accordingly heavy. Furthermore, the approach based on a plurality of individual components is structurally complex and expensive to produce. 
   DE-A-34 12 047 A1 discloses a generic device for adjusting the tilt of the backrest of a seat, especially for motor vehicles. The seat has a backrest frame with two laterally arranged rotary fittings driven by way of intermediate pinion gears by a drive shaft. The drive shaft is supported in the seat frame and is driven by a synchronous belt drive from a handwheel supported on the front end of the seat frame. As a result, a continuous shaft is not necessary in the backrest, and the handwheel for driving the seat back adjustment is located at a favorable site which is easy to reach. Since synchronous belt drives with their drive wheels and shafts are fundamentally subject to a certain slip behavior, there is no smooth and uniform triggering of the adjustment motion on the two lengthwise sides of the backrest, and obstacles in operation must be expected. Furthermore, the known and aforementioned approaches have the disadvantage that they are hardly suitable for reliably accommodating the peak loads which occur in the seat base structure in case of a crash, if it is used in the vehicle domain, especially in the aircraft domain. 
   SUMMARY OF THE INVENTION 
   Objects of the present invention are to provide an improved seat such that unhindered and uniform tilt adjustment operation of the entire further seat part, such as a backrest or a leg rest, is achieved and such that, in case of a crash, peak loads occurring can be reliably accommodated by the seat structure of the vehicle seat, also in the form of an aircraft passenger seat. Other objects are to provide a seat with an economical tilt adjustment which is of simple structure. 
   The foregoing objects are basically achieved by a seat having the drive comprising an actuating means with an actuating part which can be moved lengthwise and which engages an angle drive coupled to the adjustment part and actuating a mechanical coupling. Since there is another angle drive for the other adjustment part, uniform tilt adjustment for another seat part, such as a backrest and/or leg rest, is achieved. 
   As a result of the mechanical coupling, the indicated seat parts can be uniformly swivelled over their entire width, and consequently, can be adjusted in tilt around a respective common swivelling axis. Unilateral application of force with its adverse effects is avoided. Since, as a result of the uniform application of force by the two adjustment parts and the mechanical coupling between these two parts, torsion forces within the other seat part and its resulting twisting are avoided. A load on the articulation points which form the swivelling axis is also avoided. By these points, the other seat part, such as the backrest or leg rest, is coupled to the actual seat part of the seat. The mechanical coupling allows relief of the actuating means, for example in the form of a servo-drive so that peak loads in case of a crash can be directly accommodated by the mechanical coupling and can be diverted into the seat frame. The present invention is light in structure making its use in aircraft especially efficient. It is moreover economical to produce. As a result of the mechanical approach, low maintenance costs and few failures can be expected. 
   The actuator means used are economically available commercially and are reliable in operation. In this way, it is possible to convert a small motion of the actuator or servo-drive into a corresponding path of motion for the adjustment part by the indicated angle drive. A uniform and visible tilt adjustment for the other seat part is then achieved. The angle drive allows deflection of the force applied by the actuating part, preferably in the form of an actuating rod of the actuator means in the direction of the adjustment part at almost a right angle. Reliable, dedicated tilt adjustment is possible in spite of the tight installation conditions within the seat frame. 
   In one preferred embodiment of the seat of the present invention, the mechanical force coupling includes a rigid component hinged to the angle drives. A load situation initiated in a crash, by the adjustment parts, can consequently be reliably accommodated by a rigid component with relief of the actuator. Preferably, the rigid component extends as a mechanical coupling transversely to the lengthwise direction of the seat to keep the base contour of the seat frame clamped. This arrangement distinctly increases the passive safety for the seat. 
   In another preferred embodiment of the seat of the present invention, the actuator housing is rigidly connected to the seat frame for the seat part or is coupled to the other angle drive. In the latter case, actuation of the actuator leads equally to an adjustment motion of the actuator housing and the actuating rod so that with only one actuating process, by way of these two parts, an adjustment path twice as large for the angle drive can be traversed. Preferably, for reliable operation the actuator housing is rigidly held on the seat frame, and driving for the angle drives with the adjustment parts takes place only by the actuating rod and the mechanical coupling. 
   The indicated tilt adjustment device can fundamentally be used for all parts of a seat which must be adjusted preferably in their tilt. Use of the tilt adjustment device for tilt adjustment of the backrest of an aircraft passenger seat has been found to be especially advantageous. 
   The seat configuration of the present invention can also be used as a medical treatment chair in surgery, for dentists, and for application of cosmetics, and the like. 
   The seat of the invention can be effectively used not only in an aircraft, but also on ferries, cruise ships, busses and the like. 
   Other objects, advantages and salient features of the present invention wil become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
       FIG. 1  is a schematic side elevational view of the seat frame of an aircraft passenger seat, without the leg rest and with the backrest mechanism only partially shown, according to an embodiment of the present invention; 
       FIG. 2  is a schematic perspective view of a part of the seat frame for the seat of  FIG. 1 , with a tilt adjustment for a backrest not shown in detail; 
       FIG. 3  is a schematic top plan view of the partial sections of a seat frame of  FIG. 2 , after it has been swivelled clockwise around its lengthwise axis “X” shown by the broken line as indicated by 180°, in the direction of  FIG. 2 ; and 
       FIG. 4  is a schematic side elevational view of the partial sections of the seat frame in the arrow direction Y shown of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The embodiment of the vehicle seat of the present invention shown in  FIG. 1  is an aircraft passenger seat, as is conventionally used in airliners for passengers. For better illustration, the cushion parts and the leg rest for the seat occupant are omitted. The aircraft passenger seat has a first seat part  10  and another or second seat part  12  with adjustable tilt in the form of a backrest. The backrest is positioned to be able to swivel an actuating means  14  in its tilt relative to the essentially horizontally extending first seat part  10 . The first seat part  10  can in turn be mounted on the vehicle floor by stationary legs  16  using seat rails  18 . As illustrated, especially by  FIGS. 2 and 3 , the pertinent seat structure shown in  FIG. 1  is essentially doubled in a successive arrangement, and in this way, constitutes a seat frame  20 . The pertinent structure is conventional in aircraft passenger seats and is not described in detail. 
   For tilt adjustment, the backrest  12  with its fittings is positioned to be able to swivel around a swivelling axis  22  supported in the side walls  24  of the seat frame  20 . To implement the pertinent support, the backrest  12 , with its two fitting parts on the lengthwise sides, has a forked piece  26  ( FIG. 1 ) on its bottom. The free end of one end fork piece is pivotally coupled about swiveling axis  22 . The free end of the other fork end piece has a coupling point  28  for triggering the tilt adjustment of the backrest  12  around the actual swivelling axle  22 . This structure is described below. For the sake of clarity,  FIGS. 2 and 4  show only the fork end piece to the extent it relates to the indicated coupling point  28 . In order to further implement a lightweight construction for an aircraft passenger seat, as shown in the figures, the seat rails  18  and the side walls  24  of the seat have the wall pieces which are accordingly recessed, without endangering the structural safety of the seat. 
   The actuating means  14  has two rod-like adjustment parts  30 , with their one free end engaging the other seat part  12  in the form of a backrest by a fork end piece  32  pivotally connected to the coupling point  28  of the respective fitting part for the backrest  12 . For greater clarity,  FIGS. 2 and 4  each show only one fitting part of the indicated backrest  12  as a further seat part. The arrangement shown in this way also applies comparably to the other fitting part  12  of the backrest of the aircraft passenger seat, which part is not shown in detail. 
   The two rod-like adjustment parts  30  can be moved by a common drive  34 . For a respective uniform motion of the two adjustment parts  30 , a mechanical forced coupling  36  acts between adjustment parts  30 . The drive  34  includes a conventional actuator means, not shown in detail, with an actuating rod  40  moveable lengthwise by the drive motor  38  and guided in the actuator housing  42 . As  FIG. 3  shows, in particular, the actuating rod  40  at its free end engages a first angle drive  44  at one of its free ends in an articulated manner. This first angle drive  44  in turn on its other free end engages the rod-shaped adjustment part  30  in an articulated manner. Furthermore, the angle drive  44  is connected to the already addressed mechanical coupling  36 . For the other adjustment part  30 , another second angle drive  46  is provided. The mechanical coupling  36  includes a rigid component in the form of a coupling rod  48  hinged by each of its two free ends to the two angle drives  44  and  46 . For the sake of clarity, in  FIG. 2  the angle drives  44 ,  46  with the adjustment parts  30  and with the coupling rod  48  are not shown as being connected to one another, in the manner of an exploded drawing. This description also applies to the arrangement shown in  FIG. 3 , to the extent the two angle drives  44 ,  46  are not shown joined to the free ends of the two end parts  30 , which free ends are located opposite, adjacent to the coupling point  28 . 
   In this embodiment, the actuator housing  42  is rigidly connected to the seat frame  20  for the seat part  10 . After actuating the drive motor  38 , preferably in the form of an electric motor, the actuator housing  42  is stationary, and the actuating rod  40  can be telescoped depending on the desired direction. In another embodiment, which is not detailed, the free end of the actuator housing  42  can be hinged to the second angle drive  46  so that when the actuator is actuated the two angle drives  44  and  46  are uniformly swivelled towards one another or away from one another. The pertinent, common swivelling motion is achieved for an actuator housing fixed on one side in any case by the mechanical forced coupling  36  in the form of the coupling rod  48 . In this respect, synchronous running of the two adjustment parts  30  and consequently smoothly running tilt adjustment for the backrest  12  are achieved. 
   Each angle drive  44 ,  46  has two angle arms  50  and  52 . One angle arm  50  is coupled to the pertinent adjustment part  30 . The other angle arm  52  has an engagement point  54  in articulated form for the coupling rod  48 . Between the two arms  50 ,  52  of each angle drive  44 ,  46 , a swivelling point  56  couples of the respective angle drive  44 ,  46  to the crosspiece  58  of the seat frame  20 . As viewed in  FIG. 3 , the two angle drives  44 ,  46  are able to swivel clockwise and counterclockwise around the respective swivelling points  56 . The engagement point  54  for the coupling rod  48  in the area of the first angle drive  44  is located between the coupling point of the actuating rod  40  and the swivelling point  56  for this angle drive  44 . The actuating means  40  therefore extends, as shown in  FIG. 3 , protected between the first crosspiece  58  and another crosspiece  60  extending parallel to the first crosspiece  58 . The actuator housing  42  is connected to the first crosspiece  58  by a reinforcing angle  62 . 
   For the sake of better understanding, the operation of the disclosed embodiment of the present invention is detailed described. When the seat occupant actuates a corresponding actuating switch to move the backrest  12 , back in the direction of a rest position, the occupant starts the electric drive motor  38  and the actuating rod  40  travels linearly into the actuator housing  42  held in the seat frame  20 . The first angle drive  44  then swivels counterclockwise around the swivelling point  56  in the first crosspiece  58 . The arm  50  pulls back the assigned rod-shaped adjustment part  30 , i.e., the adjustment part  30  is moved from right to left as viewed in  FIG. 3 , so that the coupling point  28  for the fitting part of the backrest  12  is likewise pulled in this direction. The displacement process affects, not only the upper adjustment part  30  as viewed in  FIG. 3 , but also the lower adjustment part  30 . The swivelling motion of the first angle drive  44  counterclockwise presses down the coupling rod  48  as viewed in  FIG. 3 . By the engagement point  54  on the second angle drive  46 , the second angle drive is swivelled clockwise around the respective swivelling point  56 . The arm  50  of the second angle drive likewise backs out the lower adjustment part  30  by the pertinent swivelling motion, i.e., the coupling point  28  is likewise moved from right to left. Via the coupling  36  in the form of the coupling rod  48 , the two angle drives  44 ,  46  are forcibly guided in their motion. The pertinent swivelling motion takes place synchronously, and the two adjustment parts  30  are uniformly and smoothly moved back at the same time. The backrest  12  is thereby swivelled around the swivelling axis  22 , When the two adjustment parts  30  are pulled into the seat frame, the coupling point  28  is likewise pulled in the direction of the seat frame. The respective fork end piece  32  (of  FIG. 1 ) swivels the backrest  12  as viewed in  FIG. 1 , clockwise around the swivelling axis  22  into a possible rest position. 
   To reverse this process, after corresponding actuation of the control switch by the seat occupant, the electric drive motor  38  is shifted into the drive direction. The actuating rod  40  of the actuator is extended. Tthe first angle drive  44  then is swivelled clockwise. By the mechanical forced coupling in the form of the coupling rod  48 , the second additional angle drive  46  is swiveled uniformly, but in the opposite direction. In the pertinent adjustment motion, the two rod-shaped adjustment parts  30  are then pushed out of the seat frame and push the fitting parts of the backrest  12 , via the respective fork end piece  32 , for the raising motion to swivel counterclockwise around the swivelling axis  22  until, for example, an almost upright backrest position as shown in  FIG. 1  is reached. 
   If, in case of a crash, a sudden load is applied to the backrest, by the seat occupant pressing the backrest  12  to the rear, the two adjustment parts  30  are likewise pressed suddenly in the direction of the interior of the seat frame  20 . The angle drives  44 ,  46  are then pushed in opposite directions against one another due to being mutually locked by the mechanical coupling  36  (coupling rod  48 ). The mechanical parts are designed to be rigid, directly accommodating the sudden crash load, without the load being diverted into the elastic actuator-actuation system. Additionally the tilt adjustment means enables a continuous uniform motion on the two lengthwise sides of the backrest by the respective fitting parts so that torsional warping of the backrest  12  is precluded. The swivelling axis  22  is designed for tilting and is relieved accordingly. The indicated tilt position need not be limited to backrests, but can also be used for example for the leg rest, and optionally for tilt adjustment of the actual seat part  10 . In addition to the described electrical actuator means, optionally hydraulically operating actuating means or spindle drives can also be used. Since, in the latter case, for a linear extension motion the actuating rod  40  must then be turned by its screw thread, a corresponding rotary guide must be provided in the area of the coupling point of the first angle drive  44  to be able to convert the rotary motion of the spindle drive directly into swivelling motion for the angle drive  44 . 
   While one embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.