Abstract:
A support for an aircraft seat, table or other piece of equipment has a lower support link that sweeps out a lateral arc. The lower support link cooperates with a conventional linear track to support the piece of equipment. The linear track provides fore/aft movement substantially orthogonal to a line tangent to the center of the lateral arc. A pilot link is operatively attached to the piece of equipment to form a four-bar linkage that maintains the equipment in a predetermined rotational attitude as the lower support link sweeps out its lateral arc.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The application is a continuation-in-part of U.S. application Ser. No. 12/048,646 filed on Mar. 14, 2008 now U.S. Pat. No. 7,905,450, which claims priority of U.S. provisional application No. 60/908,359 filed on Mar. 27, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to aircraft interior equipment and, more particularly, to equipment supports for seats, tables and the like. 
     Aircraft manufacturers often require business class passenger seats in their aircraft that can translate in the fore/aft and lateral directions for occupant comfort and convenience. The tracking mechanism that provides this function must be robust enough to withstand various use/abuse loads, in-flight gust loads, and crash loads without mechanical failure. Conventional state of the art tracking mechanisms commonly employ two sets of linear tracks consisting of parallel tubes or rails arranged in a rectangular array, two rails for lateral movements and the other two rails for fore/aft movement. The rails used in these conventional orthogonal linear track systems are typically spaced far apart for structural stability. Because of this, it is almost always necessary when locking the position of the seat after a move, that all four rails be locked. If not, the resultant unbalanced moment loads exerted by the occupant can create an undesirable “spongy” feel. This characteristic can be mitigated by employing increasingly heavier and larger elements (e.g., larger rails, larger bearings, etc.). Large and heavy, however, are always undesirable in aircraft seat design where space and weight are at a premium. 
     Having to lock all four rails of conventional orthogonal linear track arrangements also complicates the control mechanism because of the need to simultaneously lock four separate locations with, typically, a single-hand control. Lateral motion in an orthogonal linear track design is also limited by the width of the seat and the internal real estate required to lock the lateral rails. To increase the lateral range of motion, it is necessary to increase the width of the seat to accommodate the longer rails. Accordingly, what is needed is a support mechanism for aircraft seats and other equipment that provides orthogonal axes of motion without the large footprint and the weight problems associated with conventional orthogonal linear track designs. 
     SUMMARY OF THE INVENTION 
     The present invention solves the foregoing problem by providing a support that moves angularly rather than linearly for at least one of the axes of motion. According to an illustrative embodiment, the equipment support has a sturdy lower support link that sweeps out a lateral arc. The lower support link supports a platform that has a conventional linear track. The linear track provides for fore/aft movement substantially orthogonal to a line tangent to the center of the lateral arc. A lightweight pilot link is attached to the platform to form a parallelogram linkage that maintains the platform in a rotationally fixed attitude as the lower support link sweeps out its lateral arc. This gives the lateral movement a quasi-linear feel even if the fore/aft linear track is locked. If the fore/aft linear track is unlocked, the lateral movement can be purely linear. In an alternative embodiment, the lower link supports the equipment support directly. The lower link, in turn, is supported by a frame mounted to a conventional linear track to provide fore/aft movement to complement the lateral arc movement provided by the lower link. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures in which like references designate like elements and, in which: 
         FIG. 1  is an exploded perspective view of a first embodiment of an equipment support incorporating features of the present invention; 
         FIG. 2  is a bottom view of the embodiment of  FIG. 1  in its extreme left forward position; 
         FIG. 3  is a bottom view of the embodiment of  FIG. 1  in its extreme right forward position; 
         FIG. 4  is a bottom view of the embodiment of  FIG. 1  in its extreme left rear position; 
         FIG. 5  is a bottom view of the embodiment of  FIG. 1  in its extreme right rear position; 
         FIG. 6  is an exploded perspective view of a second embodiment of an equipment support including a rotating sub-base member; 
         FIG. 7  is an exploded perspective view of a third embodiment of an equipment support including a linear track attaching the equipment support to the airframe; and 
         FIG. 8  is an exploded perspective view of a fourth embodiment of an equipment support including a linear track attaching the equipment support to the airframe and an additional bearing support. 
     
    
    
     DETAILED DESCRIPTION 
     The drawing figures are intended to illustrate to the general manner of construction and are not necessarily to scale. In the detailed description and in the drawing figures, specific illustrative examples are shown and herein described in detail. It should be understood, however, that the drawing figures and detailed description are not intended to limit the invention to the particular form disclosed, but are merely illustrative and intended to teach one of ordinary skill how to make and/or use the invention claimed herein and for setting forth the best mode for carrying out the invention. 
     With reference to  FIGS. 1-5 , equipment support  10  comprises a base member  12 , which is adapted to be rigidly affixed to a frame  14 . Frame  14  is provided with a plurality of devises  16  which allow frame  14  to be rigidly mounted to an aircraft floor or other surface. Frame  14  may also be attached to the aircraft by means of conventional floor tracking or other means and therefore is not limited to the pin and clevis attachment of the illustrative embodiment. A support link  18  is mounted to base  12  by means of a rotating joint  20  comprising a shaft  22  supported by a thrust bearing  24  fitted to a corresponding recess in base  12  so that support link  18  is free to rotate about a vertical axis  26  defined by thrust bearing  24 . Support link  18  is preferably formed of a lightweight material such as aluminum alloy or carbon fiber, such that support link  18  is capable of supporting the entire weight of an occupied passenger seat or other equipment mounted to support link  18 . 
     An equipment platform  28  is mounted to support link  18  by a means of a second rotating joint  30  consisting of shaft  32  and a corresponding thrust bearing (not shown) fitted to a corresponding recess in equipment platform  28  so that equipment platform is free to rotate about a second vertical axis  36  defined by shaft  32 . 
     As can be determined from the foregoing, the two rotational axes about shafts  22  and  32  enable equipment platform  28  to sweep through an arc having a radius equal to the offset between the first vertical axis  26  and the second vertical axis  36 . In order to maintain equipment platform  28  in a fixed rotational attitude relative to base  12 , a pilot link  38  is attached between equipment platform  28  and base  12  by means of a third rotating joint  40  and a fourth rotating joint  42 , so that pilot link  38  rotates about a third vertical axis  44  that is parallel to and offset from first vertical axis  26  while equipment platform  28  rotates about a fourth vertical axis  46  that is offset from and parallel to second vertical axis  36 . Because support link  18  is capable of supporting the entire load, pilot link  38  supports none (or only a negligible amount) of the vertical or lateral loads exerted by equipment platform  28 , and instead resists only rotational loads. Therefore, pilot link  38  can be of much lighter construction than support link  18 . Accordingly, rotating joints  40  and  42  may be conventional light duty ball or even sleeve bearings. 
     With particular reference to  FIGS. 2-4 , which depict the full range of motion of the illustrative embodiment, the length of pilot link  38  (defined as the distance between third vertical axis  44  and fourth vertical axis  46 ) is selected to be the same as the length of support link  18  (defined as the distance between first vertical axis  26  and second vertical axis  36 ). The offset between first vertical axis  26  and third vertical axis  44  is also selected to be the same as the offset between second vertical axis  36  and fourth vertical axis  46 . Accordingly when assembled, the longitudinal axis  50  of support link  18  (defined as the line of axis through first vertical axis  26  and second vertical axis  36 ) is parallel to the longitudinal axis  52  of pilot link  38  (defined as a line of action passing through third vertical axis  44  and fourth vertical axis  46 ). Similarly, the longitudinal axis  54  of base  12  (defined as a line of action passing through first vertical axis  26  and third vertical axis  44 ) is parallel to the effective longitudinal axis  56  of equipment support  28  (defined as a line of action passing through second vertical axis  36  and fourth vertical axis  46 ). 
     As can be determined from the foregoing, the geometry of the linkage ensures that longitudinal axes  50  and  52  are parallel at all times irrespective of the rotational position of support link  18  and pilot link  38 . Accordingly, the effective longitudinal axis of equipment support  28 , and with it support  28  itself, is always maintained in a fixed rotational attitude relative to longitudinal axis  54  of base  12 . Although in the illustrative embodiment the geometry of the linkage is selected to produce a parallelogram linkage, for other applications (e.g., conference tables in larger business aircraft) a trapezoidal or other unequal arm linkages may be incorporated to produce predetermined angular and/or translational motion of equipment platform  28  as a function of lateral movement without departing from the scope of the present invention. 
     As can be determined from the foregoing, support link  18  and pilot link  38  cooperate to permit equipment platform  28  to move left and right relative to base  12  through an arc that approximates the left to right movement enabled by much heavier and more complex linear seat tracks of the prior art. To provide fore and aft movement, equipment platform  28  is provided with a plurality of rollers  58  that engage corresponding tracks  60  formed in seat frame  62 . Because seat frame  62  is necessarily longer than it is wide, there is sufficient room within the confines of seat frame  62  to incorporate full fore/aft movement without track  60  or rollers  58  extending beyond the footprint of the seat frame itself. The combination, however, of the linear track comprising rollers  58  and track  60  with the support linkage comprising support link  18  and pilot link  38  considerably simplifies the release mechanism. This is because the lateral movement of equipment platform  28  may be controlled by locking support link  18  rotationally, for example by means of a pin engaging one of a plurality of holes  66  formed in metering plate  68  attached to base  12  or by other means that lock the single support link  18  rotationally, rather than locking two parallel rails simultaneously as in the prior art. 
     With Reference now to  FIG. 6 , the ability of seat frame  62  to swivel may be provided by substitution of a sub-base  612  in place of the rigidly mounted base  12  of the embodiment of  FIG. 1 . As with base  12 , sub-base  612  includes a thrust bearing  24  for supporting support link  18  as well as an attachment point for third rotating joint  40  of pivot link  38 . Additionally, however, the lower surface of sub-base  612  includes a thrust bearing (not shown) coaxial with thrust bearing  24 . The thrust bearing of sub-base  612  rides on the upper surface  614  of frame  14  thus enabling the entirety of equipment support  10  to rotate as a unit about frame  14 . A distinct advantage of this arrangement is the fore/aft and lateral adjustment axes of equipment support  10  rotate with seat frame  62  rather than remaining fixed with respect to the floor of the aircraft. This allows for much more intuitive movement of the seat frame by the user than would otherwise be possible. Once adjusted, the rotational movement of sub-base  612  may be locked by moving lock pin  615  through guide hole  616  to engage one of a plurality of holes  618  in metering plate  620  attached to frame  14 . 
     With reference now to  FIG. 7 , an alternative embodiment of an equipment support  710  comprises a base member  712  which is adapted to be rigidly affixed to a frame  714 . Frame  714  is provided with a plurality of devices  716  which allow frame  714  to be rigidly mounted to a platform  728 . To provide fore and aft movement, platform  728  is provided with a plurality of rollers  758  that engage corresponding tracks  760  which are rigidly mounted to an aircraft floor or other surface. Frame  714  may also be attached to platform  728  by welding and/or platform  728  may be integrally formed with frame  714 . Accordingly, it is not intended that the invention be limited to the pin and device attachment of the illustrative embodiment. 
     Support link  718  is mounted to base  712  by means of a rotating joint  720  comprising a shaft  722  supported by a thrust bearing  724  fitted to a corresponding recess in base  712  so that support link  718  is free to rotate about a vertical axis  726  defined by thrust bearing  724 . An equipment platform such as seat frame  762  is mounted to support link  718  by means of a second rotating joint  730  consisting of shaft  732  and a corresponding thrust bearing (not shown) fitted to a corresponding recess in seat frame  762  so that seat frame  762  is free to rotate about a second vertical axis  736  defined by shaft  732 . 
     As can be determined from the foregoing, the two rotational axes about shafts  722  and  732  enable seat frame  762  to sweep through an arc having a radius equal to the offset between the first vertical axis  726  and the second vertical axis  736 . In order to maintain seat frame  762  in a predetermined rotational attitude relative to base  712 , a pilot link  738  is attached between seat frame  762  and the base  712  by means of a third rotating joint  740  and a fourth rotating joint  742 , so that pilot link  738  rotates about a third vertical axis  744  that is parallel to and offset from first vertical axis  726  while seat frame  762  rotates about a fourth vertical axis  746  that is offset from and parallel to second vertical axis  736 . As with the previous embodiments, because support link  718  is capable of supporting the entire load, pilot link  738  supports none (or only a negligible amount) of the vertical or lateral loads exerted by seat frame  762 . Instead, pilot link  738  resists only rotational loads and, therefore, can be of much lighter construction than support link  718 . In an additional embodiment as shown in  FIG. 8 , a bearing support  812  with an additional thrust bearing may be disposed between seat frame  762  and support link  718  to enable seat frame  762  to swivel independently of support link  718 . 
     As can be determined from the foregoing, support link  718  and pilot link  738  cooperate to permit seat frame  762  to move left and right relative to frame  714  through an arc that approximates the left to right movement enabled by much heavier and more complex linear seat tracks of the prior art. Simultaneously, platform  728  provides a complementary fore and aft movement. 
     Although certain illustrative embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention shall be limited only to the extent required by the appended claims and the rules and principles of applicable law.