Patent Publication Number: US-6220658-B1

Title: Retractable tray table

Description:
CLAIM OF PRIORITY 
     This application claims priority to U.S. provisional application No. 60/104,524, filed Oct. 16, 1998, and which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     This invention generally relates to tray tables for a vehicle seat. More specifically, this invention relates to a tray table for a vehicle seat movable between a retracted or stowed position and an extended or use position. 
     BACKGROUND 
     It is known in the art to stow a tray table adjacent a seat, usually under one of the armrests. The tray table is typically movable to one or more positions, such as a stowed position and a use position. Prior tray table designs, however, typically suffer from unreliable rotation and locking mechanisms. For ease of use, it is paramount to provide a tray table moveable from stowed and use positions through simple and reliable rotating and locking mechanisms. 
     SUMMARY OF THE INVENTION 
     The tray table assemblies according to the invention are simple and reliable. First, a cam and follower locking mechanism allows the pivot arm to rotate upon an axis and lock in one or more positions, such as a stowed position and a use position. The pivot arm locks into position upon rotation of the arm to that position. A locking mechanism is released by continued rotation of the pivot arm in the same direction, beyond the locked position. Release of the locking mechanism allows the pivot arm to rotate in the opposite direction, to the other locked position. 
     Second, a telescoping pivot assembly allows a support arm to translate along and rotate about the horizontal axis and lock in one or more positions, such as a stowed position and a use position. The support arm locks into the stowed and use positions upon rotation of the arm to one of the positions. The locking mechanism is released by depressing an actuator button, which permits the support arm to translate and rotate to the other position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various advantages of the present invention will become apparent to those skilled in the art after reading the following specification and by reference to the drawings in which: 
     FIG. 1 is a perspective view of a vehicle seat assembly containing the cam and follower locking mechanism of the present invention in conjunction with a tray table shown in the stowed position; 
     FIG. 2 is a fragmentary perspective view of the armrest and tray table assembly of the seat shown in FIG. 1 with the tray table shown in the stowed position; 
     FIG. 3 is a fragmentary perspective view similar to FIG. 2 showing the tray table in an intermediate position between the use and stowed positions; 
     FIG. 4 is a perspective view like FIG. 3 showing the tray table in the process of being deployed with the tray table pivot arm in the use position; 
     FIG. 5 is a fragmentary perspective view like FIG. 4 with the pivot arm in the use position and the tray table rotated 90° relative to the pivot arm to a tray table use position; 
     FIG. 6 is an exploded perspective view of the armrest, tray table and pivot arm together with the cam and follower locking mechanism of the present invention; 
     FIG. 7 is a plan view of the cam and follower locking mechanism of the present invention; 
     FIGS. 8-12 are side views illustrating the motion of the follower of the locking mechanism and its interaction with the cam surfaces to lock and release the pivot arm in the stowed and use positions; 
     FIG. 13 is a perspective view of an armrest and tray table assembly according to a second embodiment of the invention with the tray table shown in the stowed position; 
     FIG. 14 is a fragmentary perspective view of the armrest and tray table assembly of FIG. 13 with the tray table in an intermediate position between use and stowed positions; 
     FIG. 15 is a fragmentary perspective view similar to FIG. 14 showing the tray table in yet another intermediate position between the use and stowed positions; 
     FIG. 16 is a fragmentary perspective view of the armrest and tray table assembly of FIGS. 13-15 with the tray table in the use position; 
     FIG. 17 is a fragmentary view of the tray table of FIGS. 13-16 with a container holder shown in the deployed position; 
     FIG. 18 is a partial side view of a safety release for the tray table of FIGS. 13-16; 
     FIG. 19 is a perspective view of the tray table of FIGS. 13-16 in a released position; 
     FIG. 20 is a sectional view of a locking mechanism for the tray table of FIGS. 13-16; 
     FIG. 21 is a partial sectional view of the locking mechanism of FIG. 20; 
     FIG. 22 is a partial side view of a pivot assembly for the tray table of FIGS. 13-16; and 
     FIG. 23 is a sectional view of the pivot assembly along lines  23 — 23  of FIG.  22 . 
     FIG. 24 is an exploded fragmentary perspective view of the pivot assembly of FIG.  22 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A retractable tray table of the present invention is contained within the seat assembly  10  shown in FIG. 1. A seat assembly  10  is a captain&#39;s chair for a motor vehicle including a pedestal  12 , a generally horizontal seat bottom  14  and a seat back  16  extending upwardly from the rear end of the seat bottom  14 . The seat assembly  10  includes an armrest  18  extending generally horizontally and forward from the seat back  16  along the right side edge  20  of the seat back. The left side armrest is not shown for clarity. The left side armrest, if on the outboard side of the seat, may be incorporated into a door panel or mounted to the seat back  16 . While not shown, the armrest  18  could alternatively be used on the left side of the seat back  16 . In the embodiment shown, the armrest  18  is fixed in position relative to the seat back and is not rotatable from its generally horizontal, forwardly extending position shown in FIG.  1 . The invention, however, is not limited to a fixed position armrest. 
     A tray table  22  is mounted to the armrest  18  through a pivot assembly including a pivot arm  34  and a hinge  44 , and hangs downwardly from the armrest in a stowed position as shown in FIGS. 1 and 2. The body  28  of the armrest  18  has a channel  24  that is open from the bottom of the armrest  18  and is visible at the front end  26  of the armrest  18 . As shown in FIG. 6, the armrest body  28  is coupled to a support arm  30 , which is secured to the seat back with a fastener (not shown) extending through an aperture  32  in the support arm  30 . The pivot arm  34  is attached to a forward portion of the support arm  30  for rotation about a pivot  36  from a stowed position within the channel  24  of the armrest body  28  to a use position extending forward from the armrest  18 . The movement of the tray table  22  to its use position is illustrated by the arrow  38  in FIG.  3  and the arrow  40  in FIG.  4 . The pivot  36  defines an axis of rotation  42  for the pivot arm  34  that is perpendicular to the support arm  30 , as shown in FIG.  6 . The pivot arm  34  rotates about the axis  42  as the pivot arm  34  is moved between the stowed position shown in FIG.  2  and the use position shown in FIG.  5 . 
     With reference to FIGS. 2-5, the tray table  22  is connected to the pivot arm  34  by the hinge  44 , which is attached to the pivot arm  34  and tray table  22  by fasteners, such as screws  46 , as best shown in FIG.  6 . The hinge  44  enables the tray table  22  to rotate from a generally vertical position, parallel with the pivot arm  34  and armrest  18 , to a horizontal position shown in FIG. 5 in which the tray table  22  extends laterally and overlies a portion of the seat bottom  14 . Rotation of the tray table  22  about an axis parallel to support arm  30  is shown by the arrow  48  in FIG.  5 . 
     With reference to FIGS. 6 and 7, a cam and follower locking mechanism  50  is illustrated. The pivot arm  34  includes a pivot block  58  through which the pivot  36  extends to rotatably mount the pivot block  58  to the support arm  30 . A breakaway arm  60  is coupled to the pivot block by a pin  62  which enables the breakaway arm  60  to rotate about the axis  64  defined by the pin  62 . When the pivot arm  34  is in the use position, the axis  64  will be generally vertical, thereby allowing the breakaway arm  60  to rotate laterally away from the seat bottom  14  and seat back  16 . The breakaway arm  60  is coupled to an extension tube  66  by a pin  68 . The hinge  44  is coupled to the extension tube  66  to mount the tray table  22  to the pivot arm  34 . The breakaway arm  60  and the extension tube  66  can be made of a single piece if desired. 
     The locking mechanism  50  includes a follower  52  that is rotatably mounted to the pivot arm  34  by a pivot  54 . The follower  52  is rotationally biased about the pivot  54  by a spring  56 . The follower  52  is coupled to the pivot block  58  of the pivot arm  34 . The cams  70 ,  72  extend laterally from the support arm  30  and form locking cam locking surfaces  74 ,  76 , respectively. The follower  52  engages the locking surfaces  74 ,  76  to hold the pivot arm  34  in the stowed and use positions, respectively. 
     The motion of the follower  52  during various phases of operation of the locking mechanism  50  is shown in FIGS. 8-12. The follower  52  is symmetrical in its configuration having a radial inner end  78  and a radial outer end  80 . The radial outer end  80  engages the cam locking surface  74  of the cam  70  to hold the pivot arm in its stowed position. The locking surface  74  has a concave bight  82  (FIG. 10) which receives the outer end  80  of the follower  52  in the stowed position to lock the pivot arm  34  in place. The outer end  80  of the follower  52  is disposed in the concave bight  82  of the cam  70  as shown in the solid line position of FIG.  8 . 
     The pivot arm  34  is released from the locked, stowed position by rotating the pivot arm  34  clockwise, as viewed in FIG. 8, through the arc  84 . As the pivot arm  34  is rotated through the arc  84 , the cam locking surface  74  will cause the follower to rotate about the pivot  54 . An intermediate position of the follower  52  is shown as position A in FIG.  8 . Once the outer end  80  of the follower  52  clears the cam locking surface  74 , the follower  52  will rotate to the position B under the force of the bias spring  56 . In the position B, the spring  56  is in a free or unstressed position in which it does not act upon the follower  52 . Rotation of the follower  52  in either direction about the pivot  54  will result in the stressing of the spring  56  and a resulting bias force acting on the follower  52 . In the particular embodiment shown, when the follower  52  is in the unstressed position of the spring  56 , the follower  52  is oriented generally radially relative to the pivot  36 . This radial orientation of the follower  52  in the unstressed position of the spring  56  is not essential to the invention but it is helpful in describing the motion of the follower  52 . 
     Once the pivot arm  34  has been rotated through the arc  84 , the pivot arm  34  is free to rotate in the counterclockwise direction. After this counterclockwise rotation of the pivot arm  34  begins, the outer end  80  of the follower  52  will again contact the surface  74  of the cam  70 . This contact is shown in the solid line position of the follower  52  in FIG.  9 . Continued counterclockwise rotation of the pivot arm  34  causes the follower  52  to rotate about its pivot  54  first to the position C shown in FIG. 9, and then to the position D in which the outer end  80  clears the tip  86  of the cam  70 . Once the pivot arm  34  rotates beyond the position D, the follower  52  is then rotated about the pivot  54  to the unstressed position of the spring  56 , shown as position E, in which the follower  52  is oriented generally radially relative to the axis  42 . 
     With reference to FIG. 10, the follower is shown in various positions as the pivot arm  34  continues to rotate counterclockwise about the pivot  36  to the use position of the pivot arm  34 . The follower  52  remains in the radially oriented position as the pivot arm  34  rotates. 
     With reference to FIG. 11, the follower  52  is shown in a position F in which the follower  52  contacts the lower surface  88  of the cam  72 , opposite the cam locking surface  76 . Continued rotation of the pivot arm  34  causes the follower  52  to rotate counterclockwise about the pivot  54  to the position G, then to the position H, and ultimately to the solid line position where the radially inner end  78  of the follower  52  clears the tip  90  of the cam  72 . Here, the radially inner end  78  seats into the concave bight  92  (FIG. 9) of the cam locking surface  76 . In this position of the follower  52 , the pivot arm  34  is locked in the use position and cannot be rotated clockwise from this position without first releasing the locking mechanism  50 . 
     Release of the locking mechanism  50  is accomplished by continued counterclockwise rotation of the pivot arm  34  through the arc  94 , which requires that the follower  52  rotate through the position J until the inner end  78  clears the cam  72  enabling the follower  52  to rotate to position K by the force of the spring  56 . This movement releases the locking mechanism  50 , allowing the pivot arm  34  to again be rotated clockwise to the stowed position. This motion is shown in FIG. 12 with the follower  52  shown in the solid line position designated as K. The clockwise rotation of the pivot arm  34  results in the follower  52  first moving to the position L, and then to the position M as the inner end  78  once again engages the cam  72 . As the pivot arm  34  continues to rotate clockwise, the follower  52  moves through the positions N, P, and Q shown in FIG.  12 . After the pivot arm  34  moves the follower  52  past the position Q in FIG. 12, the spring  56  will rotate the follower  52  to the spring unstressed position oriented generally radially from the pivot  36 . The follower  52  will stay in this position until the pivot arm  34  nears the stowed position and the follower contacts the cam  70  as shown in position R of FIG.  8 . Continued rotation of the pivot arm  34  causes the follower  52  to rotate counterclockwise about the pivot  54  until the radially outer end  80  seats into the concave bight  82  in the cam  70 . 
     The locking mechanism  50  is a simple mechanism having one moving part, the follower  52 , which engages different cams to hold the pivot arm  34  in either the stowed or use positions. As illustrated in the drawings, the pivot arm  34  is used to carry a tray table  22 . A rotating pivot arm  34  held in place by a lock mechanism  50  could be used for other purposes. For instance, the locking mechanism  50  could be used for a rotating armrest that is attached to a seat back armrest to rotate between a use position and a stowed position. Furthermore, the locking mechanism  50  is not limited to use with a seat back mounted device. 
     The pivot arm  34  and the support arm  30  will typically be made of steel or other metals. However, other materials including plastic materials may be used if they provide sufficient strength for the application. The follower  52  and cams  70 ,  72  can also be made of a variety of different materials including metals or plastics. In a preferred embodiment, the cams  70 ,  72  and follower  52  are made of metal to provide a noticeable noise such as a clicking sound when the follower engages the cam in the locked position. The presence of a noticeable sound as the follower engages the cams in the locked positions avoids unintended overtravel of the pivot arm beyond its locked positions to inadvertently release the locking mechanism. 
     Another embodiment of a tray table according to the invention is shown in FIGS. 13-23. With particular reference to FIG. 13, a tray table assembly  110  is mounted to a single armrest  118  extending generally horizontally and forward from a seat back (not shown), such as for a seat in a motor vehicle. A body  128  of armrest  118  has an open channel  124  that is open from the bottom of the armrest  118  and is visible at a front end  126  of the armrest  118 . The armrest  118  can be disposed on either side of a seat assembly as one of skill in the art will readily recognize. The single armrest  118 , if on the outboard side of the seat, may alternatively be incorporated into a door panel. Further, a single armrest  118  may be fixed relative to the seat back or rotatable from its generally horizontal and forwardly extending position shown in FIG.  13 . 
     The tray table assembly  110  is mounted to the armrest  118  and extends downwardly from the armrest  118  in a stowed position, as shown in FIG.  13 . The tray table assembly  110  is moveable to both a stowed position, as shown in FIG. 13, and a use position, as shown in FIG. 16, through the intermediate positions illustrated in FIGS. 14 and 15. A locking mechanism  190  releasably secures the tray table assembly  110  in both the stowed and use positions. With further reference to FIG. 14, the tray table assembly  110  includes a telescoping support arm  140  connecting a tray table  122  to the armrest  118  through a pivot assembly  160 . More specifically, the telescoping support arm  140  is pivotally connected at a proximate fixed end  142  to a pivot axle  144  mounted between walls  146 . The telescoping support arm  140  includes a smaller diameter tube  150  axially slidable in a larger diameter tube  152 . The smaller diameter tube  150  mounts pivot assembly  160  on its exposed moveable end  148 , while its opposite end is received within a bore of the larger diameter tube  152 , which at fixed end  142  is connected to armrest  118  by the pivot axle  144 . A spring  151  mounted within larger diameter tube  152  biases smaller diameter tube  150  axially extended, which assists in deploying the tray table  122  for use. At the moveable end  148  of telescoping support arm  140 , the pivot assembly  160  supports the tray table  122 . Also, the telescoping support arm  140  is intermediately supported by a releasable support assembly  180 . 
     As shown in FIG. 17, the tray table  122  includes a pocket  222  for releasably storing a container holder  220 . The container holder  220  is selectively deployed by the user for holding a beverage container, such as a cup, bottle, or can. Further, the tray table  122  preferably includes a shallow recess  224  on its top surface  121 . The recess  224  is useful for holding utensils, writing instruments, or other small articles for use by the occupant. 
     With reference to FIGS. 18 and 19, the releasable support assembly  180  is used for releasing the telescoping support arm  140  from the armrest  118  when excessive downward force has been placed on the tray table  122 , particularly when it is in the use position. When the releasable support assembly  180  is released, telescoping support arm  140  pivots via pivot axle  144  at fixed end  142 . The releasable support assembly  180  prevents damage to the telescoping support arm  140  when excessive weight, preferably in excess of 30 pounds, has been placed on the tray table  122 . 
     More particularly, releasable support assembly  180  includes a pivoting latch  182  mounted on an axle  184  and biased in a generally upright position by a spring  186  mounted coaxially on the axle  184 . The latch  182  includes a pair of arms  188  extending generally vertically upward from the axle  184  on opposite sides of the telescoping support arm  140 , joined intermediately by an offset stop bar  141 , and connected at distal ends of the arms  188  by a cylindrical catch  176 . The catch  176  releasably engages a finger  178  extending into open channel  124  and supported by the armrest  118 . At a proximate end of the arms  188  the latch  182  pivots on the axle  184 , which is disposed subjacent support arm  140 . The spring  186  mounted coaxially on the axle  184  biases the latch  182  into the generally upright position with catch  176  normally disposed behind finger  178 . The latch  182  pivots when a certain amount of downward force is exerted on the tray table  122 , whereupon catch  176  slides along surface  164  in the direction of arrow A of FIG. 18 until latch  182  is disengaged from finger  178 . Because the latch  182  is spring biased, it returns to a generally upright position when catch  176  is disengaged from the finger  178 , as shown in FIG.  18 . The stop bar  141 , shown in FIG. 19, prevents further rotation of the spring biased latch  182  when the stop bar  141  abuts telescoping support arm  140 . 
     The latch  182  is returned behind finger  178  upon directing the telescoping support arm  140 , and thus the latch  182  and the catch  176 , towards the finger  178  until the catch  176  engages the finger  178 , whereupon the catch  176  slides along a leading end  168  of the finger  178  in the direction of arrow B of FIG. 18 until the catch  176  pivots the latch  182 , as illustrated in phantom in FIG.  18 . With enough rotation of the latch  182  about pivot axle  184 , catch  176  moves behind finger  178 , at which point the latch  182  returns to normal upright engaged position. Once in this position, the telescoping support arm  140  is supported by the finger  178  and properly positioned in open channel  124  for movement of the tray table  122  between its use and stowed positions. 
     The locking mechanism  190  further defines the stowed and use positions, but in a more secure fashion. The locking mechanism  190  includes, as shown best in FIGS. 20 and 21, an actuator button  192  including a ramp  194  for disengaging a spring-biased pin  196  from an aperture  198  in telescoping support arm  140 . The aperture  198  includes a single opening in larger diameter tube  152  for selective alignment with a pair of openings in smaller diameter tube  150 . The openings in smaller diameter tube  150  define the stowed and use positions of the tray table assembly  110 . More specifically, because the smaller diameter tube  150  coaxially rotates approximately 90° relative larger diameter tube  152  during movement between the use and stowed positions, as will be explained in detail below, the openings in smaller diameter tube  150  are disposed spaced apart and approximately 90° relative each other. 
     The pin  196  actuated by button  192  is slidably mounted in a housing  200  and is biased from the housing  200  toward the telescoping support arm  140  by compression spring  202 . Further, a post  206  connected to and extending transversely from the pin  196  extends to engage a surface  208  of ramp  194 . Thus, when ramp surface  208  moves in the direction of the arrow of FIG. 20 by depressing actuator button  192 , the post  206  rides the ramp surface  208  forcing pin  196  upwardly against the bias of spring  202  in housing  200 . Upward movement of pin  196  removes the pin  196  from the aperture  198 , whereby a smaller diameter tube  150  can slide relative to larger diameter tube  152 . With reference to FIG. 16, the locking mechanism  190  is shown in phantom for locking the telescoping support arm  140  in the use position. Depressing actuator button  192  disengages pin  196  from the aperture  198  to permit the user to return the tray table  122  to its stowed position, as shown in FIG.  13 . 
     As shown in FIGS. 22-24, the pivot assembly  160  allows the tray table  122  to rotate relative telescoping support arm  140  about an axis perpendicular to the telescoping support arm  140 . More specifically, the pivot assembly  160  includes a pivot axle  162  fixed to the tray table  122  and journalled for rotation in a bushing  167  of a pivot block  164 , which is secured to the moveable end  148  of the telescoping support arm  140 . The pivot axle  162 , and thus the tray table  122 , is secured to the pivot block  164  by a screw  169 , which is secured in a threaded coaxial bore through pivot axle  162 . A washer  161  joins the screw  169  and pivot axle  162  to the pivot block  164  disposed in an opening  159  of the pivot block  164 . 
     The pivot assembly  160  further includes a locking pin  170  extending transversely downwardly from a bottom surface  132  of the tray table  122  generally parallel to but offset axially from the pivot axle  162 . The locking pin  170  slides in an arcuate channel  172  formed in a torque washer  165  and a face  166  of the pivot block  164 . The torque washer  165  is a semicircular spacer including an arcuate wall  163  against which the pin  170  slides. The wall  163  is a bearing surface providing torque to the pin  170  as it moves from a first extreme position to a second extreme position defined by the ends of arcuate channel  172  to limit rotation of the tray table  122  relative the telescoping support arm  140 . A detent  174  formed in the wall  163  at each end of the arcuate channel  172  further defines these extreme positions, which correspond to the stowed and use positions for tray table  122 . Each detent  174  is a slight depression in wall  163  at the end of arcuate channel  172  for registering locking pin  170 , which must be rotated with enough force to overcome an edge of the detent  174  to travel in the arcuate channel  172  along wall  163  to the other extreme position. Thus, the detent  174  provide a “locked” feel to the user when placing the tray table  122  in either the use or stowed position. The torque provided by wall  163  provides a “sturdy” feel to the user when rotating the tray table  122  between the use and stowed positions. 
     To use the tray table assembly  110 , a user simply presses actuator button  192  to unlock the tray table  122  from within the open channel  124 , whereupon the small diameter tube  150  of telescoping support arm  140  slides from within the large diameter tube  152  of telescoping support arm  140  under force of spring  151 . Once telescoping support arm  140  is fully extended, as shown in FIG. 14, the tray table  122  is rotated through pivot assembly  160  along an axis generally transverse to the telescoping support arm  140 , as shown in FIG.  15 . The tray table  122  is rotated approximately 180° until it is disposed generally upright, at which point it is rotated approximately 90° along an axis coaxial with telescoping support arm  140  by rotating smaller diameter tube  150  within large diameter tube  152  of telescoping support arm  140 . This axial rotation places the tray table  122  into its use position, presumably in front of a seat occupant. In this position, aperture  198  through telescoping support arm  140  is again aligned and locking pin  196  registers therein. As shown in FIG. 17, a container holder  220  can be releasably stored in a pocket  222  of the tray table  122  for use by the occupant. 
     Returning the tray table to its storage position is accomplished by simply reversing the steps above. In summary, the actuator button  192  is pressed to disengage pin  196  from aperture  198  in telescoping support arm  140 . Then, the tray table  122  is rotated approximately 90 degrees about the axis of the telescoping support arm  140  by rotating the small diameter tube  150  in the large diameter tube  152  of the telescoping support arm  140 . Once fully upright, as shown in FIG. 15, the tray table  122  is rotated approximately 180° about an axis generally perpendicular to telescoping support arm  140  through pivot assembly  160  to place the tray table  122  in the position shown in FIG.  14 . Then, the tray table  122  is slid into open channel  124  in armrest  118 , against the bias of spring  151 , until the tray table  122  locks in its storage position, wherein the pin  196  of locking mechanism  190  again engages aperture  198  in telescoping support arm  140 . 
     The telescoping support arm  140  will typically be made of steel or other metals. Other materials, however, including plastic materials may be used if they provide sufficient strength for the application. The pivot assembly  160  and locking assembly  190  can also be made of a variety of different materials including metals or plastics. 
     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.