Abstract:
A locking apparatus for a moveable component of an aircraft seat. The locking apparatus includes a housing for being slidably received in a track, a first pair of opposed cams pivotally mounted in the housing, and a release member. The cams are moved between a lock position where the cams prevent the housing from sliding within the track and a release position. The release member is selectively moveable between a first position where the cams are maintained in the lock position and a second position where the cams are maintained in the release position.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This invention relates generally to vehicle seating and more particularly to a locking apparatus for a moveable component of an aircraft seat.  
         [0002]     Seating units, particularly those in aircraft, are often provided with one or more components which are moveable so that a passenger seated therein can be comfortably supported in various positions. For example, the bottom of the seat may be translatable fore and aft. In order to provide the desired crash-worthiness, these moveable components must be securely locked in position when not actually being moved by the passenger. They must also be easy and convenient for the passenger to move when necessary, and they must withstand repeated and sometimes rough usage. Various prior art seats include electric motors or actuators to operate the moveable components, or pneumatic or hydraulic elements such as “hydrolocks”. While these type of devices provide the desired adjustability, they are relatively complex and expensive compared to purely mechanical arrangements.  
       BRIEF SUMMARY OF THE INVENTION  
       [0003]     Therefore, it is an object of the invention to provide a locking apparatus for a moveable portion of a passenger seat which allows the seat to be selectively locked in a desired position.  
         [0004]     It is another object of the invention to provide a locking apparatus that has an infinite number of locking positions.  
         [0005]     It is another object of the invention to provide a locking apparatus that is mechanical in operation.  
         [0006]     It is another object of the invention to provide a locking apparatus that is inexpensive to manufacture.  
         [0007]     These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a locking apparatus including a housing for being slidably received in a track; a first pair of opposed cams pivotally mounted in the housing, the cams being moveable between a lock position and a release position, wherein the cams prevent the housing from sliding within the track when in the lock position; and a release member selectively positionable from a first position where the cams are maintained in the lock position and a second position where the cams are maintained in the release position.  
         [0008]     According to another preferred embodiment of the invention, the locking apparatus further includes a second pair of opposed cams pivotally mounted in the housing.  
         [0009]     According to another preferred embodiment of the invention, the first pair of opposed cams and the second pair of opposed cams have offset pivot points for creating a progressive lobe for each respective cam.  
         [0010]     According to another preferred embodiment of the invention, the first pair of opposed cams and the second pair of opposed cams are connected by a spring.  
         [0011]     According to another preferred embodiment of the invention, the release member has an end having a length greater than its width.  
         [0012]     According to another preferred embodiment of the invention, the first pair of opposed cams have offset pivot points for creating a progressive lobe for each respective cam.  
         [0013]     According to another preferred embodiment of the invention, at least one roller is carried by the housing for permitting the housing to slide within the track.  
         [0014]     According to another preferred embodiment of the invention, the first pair of opposed cams are mounted in a recess of the housing.  
         [0015]     According to another preferred embodiment of the invention, the first pair of cams protrude from the housing when in the lock position to engage and prevent the housing from sliding within the track.  
         [0016]     According to another preferred embodiment of the invention, a reclining seat includes a track fixedly attached to a frame; a seat pan assembly mounted for sliding movement within the track; and a locking apparatus fixedly attached to the seat pan assembly. The locking apparatus includes a housing for being slidably received in the track; a first pair of opposed cams pivotally mounted in the housing, the cams being moveable between a lock position and a release position, wherein the cams prevent the housing from sliding within the track when in the lock position; and a release member selectively moveable from a first position where the cams are maintained in the lock position and a second position where the cams are maintained in the release position.  
         [0017]     According to another preferred embodiment of the invention, the seat pan assembly includes a pair of spaced-apart, longitudinally-extending rails connected by a plurality of cross-members.  
         [0018]     According to another preferred embodiment of the invention, the locking apparatus is positioned on an outside surface of each of the respective rails at a rear end of each rail.  
         [0019]     According to another preferred embodiment of the invention, each of the rails includes a roller for being received in a track.  
         [0020]     According to another preferred embodiment of the invention, the reclining seat further includes a seat back pivotally mounted to the seat pan assembly. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The subject matter that is regarded as the invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:  
         [0022]      FIG. 1  is a perspective view of a passenger seat including a moveable seat pan assembly;  
         [0023]      FIG. 2  is an exploded view of the seat pan assembly of  FIG. 1 ;  
         [0024]      FIG. 3  is a perspective view of a locking apparatus attached to a seat pan assembly and positioned within a track;  
         [0025]      FIG. 4  is a plan view of an exemplary locking apparatus disposed within a track in a locked position;  
         [0026]      FIG. 5  is a plan view of the locking apparatus of  FIG. 4  in a released position;  
         [0027]      FIG. 6  is an end view of the locking apparatus of  FIG. 4 ;  
         [0028]      FIG. 7  is a plan view of an alternative locking apparatus disposed within a track in a locked position; and  
         [0029]      FIG. 8  is a plan view of the locking apparatus of  FIG. 7 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     Referring now specifically to the drawings, an exemplary passenger seat constructed according to an embodiment of the present invention is illustrated in  FIGS. 1-3  and shown generally at reference numeral  10 . The seat  10  has a seat frame  11  for being attached to the deck of an aircraft (a portion of which is shown in  FIG. 2 ) and includes a seat pan assembly  12  slidably attached to the seat frame  11 , a seat bottom  13 , a seat back  14  pivotally attached to a pair of pivots  15 A and  15 B of the seat pan assembly  12 , and a headrest  16 . The seat frame  11  includes two spaced-apart, longitudinal, inward-facing C-shaped tracks  17  and  18  connected by a plate  19 . The seat pan assembly  12  includes a seat pan  20  attached to a seat pan frame assembly  21  which includes a pair of spaced-apart rails  22  and  23  connected by a plurality of cross-members  24 . Rollers  26  and  26 ′ and a locking apparatuses  27  and  27 ′ are positioned on an outside surface of the rails  22  and  23  respectively, and are sized to fit in the C-shaped tracks  17  and  18 , as shown in  FIG. 3 , to allow the seat pan assembly  12  to slide therein. In the illustrated example, the rollers  26  and  26 ′ are positioned approximately midway between a first end  28  and a second end  29  of the respective rails  22  and  23  and the locking apparatuses  27  and  27 ′ are positioned at the second end  29  of each rail  22  and  23 .  
         [0031]     The locking apparatuses  27  and  27 ′ are substantially identical in construction, therefore, only the locking apparatus  27  will be described in detail. As illustrated in  FIGS. 4-6 , the locking apparatus  27  includes two pairs of opposing cams positioned within a recess  30  of a housing  31 , each pair having an inner cam  32 A,  33 A and an outer cam  32 B,  33 B pivotally attached to the housing  31 . The pivot point for each cam  32 A,  32 B,  33 A, and  33 B is offset to create a progressive lobe  34  for each cam which increases pressure on the tracks  17  and  18  when sliding loads are applied. The outer cams  32 B and  33 B are connected by a spring  36  or other suitable structure which pulls the outer cams  32 B and  33 B towards the inner cams  32 A and  33 A, engaging and forcing the inner cams  32 A and  33 A against a release member  37  located in the center of the housing  31 . The release member  37  includes a non-circular end  38  having a length greater than its width. As illustrated, the end  38  is rectangular. In the illustrated example, a roller  39  is positioned within a recess  40  located at each corner of the housing  31  and extends slightly past an outside edge of the housing  31 , allowing the locking apparatus  27  to slide easily within the track  17 .  
         [0032]     In the locked position, the cams  32 A,  32 B,  33 A, and  33 B engage an inside surface of the track  17  to prevent the locking apparatus  27  from sliding, thereby preventing the seat pan assembly  12  from translating fore or aft with respect to the frame  11 . The cams  32 A,  32 B,  33 A, and  33 B are placed into a locked position by turning the release member  37  so that the end  38  is generally perpendicular to the track  17 . The spring  36  forces the cams  32 A,  32 B,  33 A, and  33 B to pivot towards the center of the housing  31  by pulling the outer cams  32 B and  33 B towards each other, forcing the outer cams  32 B and  33 B to engage the inner cams  32 A and  33 A, thereby moving the lobes  34  past the outside edge of the housing  31  and against the inside surface of the track  17 . As shown, cams  32 A and  32 B prevent movement in the forward direction and cams  33 A and  33 B prevent movement in the aft direction.  
         [0033]     To release the locking apparatus  27 , the release member  37  is turned so that the end  38  is generally parallel with the track  17 . The release member  37  forces the inner cams  32 A and  33 A against the outer cams  32 B and  33 B, forcing both pairs of cams  32 A,  32 B and  33 A,  33 B away from the center of the housing  31  against the spring  36 , and thereby disengaging the cams  32 A,  32 B,  33 A, and  33 B from the inner surface of the track  17  and allowing the seat pan assembly  12  to translate freely between fore and aft positions.  
         [0034]     The cams  32 A,  32 B,  33 A, and  33 B may also be turned around so that the progressive lobes  34  face inward towards the center of the housing  31 , allowing the lobes to bear against a rod, bar, tube or other member passing through the center of the locking apparatus  27 .  
         [0035]     In operation, the seat  10  is reclined by turning the release member  37  to the release position as described above, allowing the seat pan assembly  12  to translate fore and aft with respect to the seat frame  11 . Any means which allows the passenger to turn the release member  37  may be used. For example, a cable may be attached between a passenger-operable lever or button and the release member  37 , or a button may be positioned on an armrest and operably connected to a motor or hydraulic actuator for turning the release member  37 .  
         [0036]     The fore and aft movement of the seat pan assembly  12  causes the seat back  14  to move between an upright and recline position. Once a desired recline position has been determined, the seat  10  is locked in position by turning the release member  37 , as discussed above, to the lock position, allowing the cams  32 A,  32 B,  33 A,  33 B to engage the track  17 . Unlike prior art devices that use notches or slots, the locking apparatus  27  allows for infinite adjustment, since the cams  32 A,  32 B,  33 A, and  33 B are designed to engage a flat surface and do not require dimples, notches, slots, or any other type of depression to lock the seat pan assembly  12  in position.  
         [0037]     Referring now to  FIGS. 7 and 8 , in an alternate embodiment of the invention, a locking apparatus  127  includes one pair of opposing cams positioned within a recess  130  of a housing  131 , the pair having an inner cam  132 A and an outer cam  132 B pivotally attached to the housing  131 . The pivot point for each cam  132 A and  132 B is offset to create a progressive lobe  134  for each cam. The outer cam  132 B is connected to a post  141  by a spring  136  or other suitable structure which pulls the outer cam  132 B towards the inner cam  132 A, forcing the inner cam  132 A against a release member  137  located in the center of the housing  131 . The release member  137  includes a non-circular end  138  having a length greater than its width. As illustrated, the end  138  is rectangular. In the illustrated example, a roller  139  is positioned within a recess  140  located at each of the two aft corners of the housing  131  and extends slightly past an outside edge of the housing  131 , allowing the locking apparatus  127  to slide easily within the track  17 .  
         [0038]     In the locked position, the locking apparatus  127  only prevents the seat pan assembly from translating in the fore direction, allowing the seat pan assembly to freely move in the aft direction. In this embodiment, the cams  132 A and  132 B engage an inside surface of the track  17  to prevent the locking apparatus  127  from sliding, thereby preventing the seat pan assembly  12  from moving fore with respect to the frame  11 . The cams  132 A and  132 B are forced into a locked position by turning the release member  137  so that the end  138  is generally perpendicular to the track  17 . The spring  136  forces the cams  132 A and  132 B to pivot towards the center of the housing  131  by pulling the outer cam  132 B towards the center of the housing  131 , forcing the outer cam  132 B to engage the inner cam  132 A, thereby forcing the lobes  134  past the outside edge of the housing  131  and against the inside surface of the track  17 .  
         [0039]     To release the locking apparatus  27 , the release member  137  is turned so that the end  138  is generally parallel with the track  17 . The release member  137  forces the inner cam  132 A against the outer cam  132 B, forcing the cams  132 A and  132 B away from the center of the housing  131  against the spring  36 , and thereby disengaging the cams  132 A and  132 B from the inner surface of the track  17 .  
         [0040]     The foregoing has described a locking apparatus for a vehicle seat. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation, the invention being defined by the claims.