Abstract:
A chair with an extendable footrest for accommodating users of different height includes a seat frame, a slide frame mounted to slide on the seat frame between a retracted and extended position and a footrest frame mounted on the slide frame to move between down and up positions. A rotatable drive shaft is mounted on the seat frame and an elongated drive arm is secured at one end to the drive shaft. An extending linkage is connected between the other end of the drive arm and the slide frame to move the footrest frame from the down to the up position and thereafter move the slide frame from the retracted to the extended position, when the drive shaft is rotated in one direction. A retracting linkage connected between the said other end of the drive arm and the slide frame serves to the slide frame from the extended to the retracted position with the footrest frame in the up position when the drive shaft is rotated in the opposite direction. The chair may include a massage mechanism incorporated anywhere within the chair, including the footrest.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Application No. 60/472,443, filed May 21, 2003, the disclosure of which is hereby incorporated by reference. 

   FIELD OF THE INVENTION 
   This invention provides an extendable footrest for a chair. 
   BACKGROUND 
   There exist a number of chairs having footrests on which a user may relax his or her legs. One such chair with a footrest includes a back massager and a calf and leg massager incorporated in a stationary or rotatable footrest. Examples of the aforementioned massagers are disclosed in U.S. Patent Publications US2002/0161316 and US2003/0006639, the contents of which are hereby incorporated by reference. As massage or non-massage chairs typically should accommodate users of different height, it would be desirable to have a chair with an extendable footrest whereby a user may adjust the location of the footrest to personal preference. 
   SUMMARY 
   There is therefore provided according to an exemplary embodiment of the present invention an extendable footrest for a chair, which may or may not incorporate a massage mechanism within the backrest, footrest or other portion of the chair. The chair includes a seat frame, a slide frame mounted to slide on the seat frame between a retracted and extended position and a footrest frame mounted on the slide frame to move between down and up positions. A rotatable drive shaft is mounted on the seat frame and an elongated drive arm is secured at one end to the drive shaft. An extending linkage is connected between the other end of the drive arm and the slide frame to move the footrest frame from the down to the up position and thereafter move the slide frame from the retracted to the extended position, when the drive shaft is rotated in one direction. A retracting linkage connected between the said other end of the drive arm and the slide frame serves to the slide frame from the extended to the retracted position with the footrest frame in the up position when the drive shaft is rotated in the opposite direction. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features of the present invention will be better understood when read in context of the following detailed description and accompanying drawings, wherein: 
       FIG. 1  is a perspective view of an exemplary chair with an exemplary extendable footrest; 
       FIGS. 1A through 9  illustrate various aspects of an exemplary extendable footrest according to the present invention; 
       FIG. 10  is a view of the footrest end plates in a full down position, with the slide frame fully retracted within the seat frame; 
       FIGS. 11 and 12  show views of components of the footrest between a fully retracted and a fully extended position; 
       FIG. 13  is a view of the footrest in a fully extended position; 
       FIGS. 14 through 16  show additional vies of the extending footrest; and 
       FIGS. 17 through 20  show various ways for powering the drive shaft of the extendable footrest. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a reclining chair  20  includes a circular base  22 , an upright pedestal  23 , a seat  24 , and a footrest  26 . A separate respective tear drop-shaped end plate  27  is secured to each end of the footrest (only 1 end plate is shown in  FIG. 1 ). The smaller end of each end plate is secured to a slide frame (as described in detail below) so the end plates and footrest can pivot about a horizontal transverse axis. 
   In brief, the footrest can be deployed from vertical (down position) to horizontal (up position) about the transverse axis, and then be extended forward several inches to accommodate persons of different heights. This is particularly useful with reclining chairs of the type shown in  FIG. 1  in which the footrest includes a pair of longitudinally extending and upwardly opening cavities  28  to receive the calves of the person seated in the chair, which can be activated to massage the legs and other parts of the anatomy of the seated person. 
     FIGS. 1A-9  show diagrammatically the operation of this invention. A slide frame  30  is mounted in a seat frame  32  to move on rollers  34  (or any other means of transportation, e.g., glide rails, bushings, linear ball bearings, and the like) and slide between a retracted position ( FIGS. 1A-7 ) and an extended position ( FIG. 9 ).  FIG. 8  shows the slide frame in an intermediate position between the retracted and extended positions. 
   The footrest (shown only as an end plate  27  in  FIGS. 1A-9 ) moves from a full down position as shown in  FIG. 1A  to a full up position as shown in  FIGS. 6 and 6A  by operation of an extending linkage  36 . 
   As the footrest moves from the down position shown in  FIG. 1A  toward the up position shown in  FIGS. 6 and 6A , a slide frame lock  38 , which is secured to the seat frame  32  by a transverse pivot pin  40  ( FIG. 4A-FIG .  6 A) remains engaged to lock the slide frame  30  from moving from the retracted toward the extended position. With the footrest in the intermediate (that is, between fully down and fully up) position shown in  FIGS. 2-5 , the slide frame lock  38  also prevents the footrest from moving down while the mechanism is in any intermediate position. 
   As the footrest approaches the full up position as shown in  FIGS. 5-6A , a footrest deployment lock  42  on the extending linkage  36  locks the extending linkage with the footrest in the up position. At the same time, a transverse slide frame lock release shaft  44  ( FIG. 5A ), engages the underside of the slide frame lock and pivots that lock in a clock wise (as viewed in  FIGS. 5A and 6A ) direction so the rear end of the slide frame lock moves down and no longer prevents the slide frame from moving from the retracted toward the extended position. Further actuation of the extending linkage  36  after the footrest deployment lock  42  is released (as shown in  FIG. 6 ) causes the slide frame  30  to roll forward (right to left as shown in  FIG. 6 ) from the retracted position shown in  FIGS. 1A-6  toward the fully extended position shown in  FIG. 9 . Thereafter, the operation just described can be reversed so that a retracting linkage  46  acts to unlock the extending linkage  36  and permits the slide to move frame from the extended position to the retracted position. The footrest deployment lock is disengaged so the extending linkage can collapse to afford its original state, and permit the footrest to be moved to the down position shown in  FIG. 1A . 
   The invention is described in more detail below to explain how the extending and retracting linkages are constructed and powered. 
     FIG. 10  shows the footrest end plates  27  in a full down position, with the slide frame  30  (shown best in  FIG. 13 ) fully retracted within the seat frame  32 . A linear actuator  50  is bolted to the seat frame  32 , and reciprocates a push shaft  52  in a longitudinal direction in response to electrical signals supplied from a control unit (not shown) through an electrical cable  54 . The linear actuator is powered by a conventional reversible electric motor (not shown) connected through a conventional gear reduction drive (not shown) to the push shaft  52 . The push shaft makes a close sliding fit through a push shaft guide  56  bolted to the seat frame. The forward end of the push shaft is slotted and carries a transverse roller  58 , which rides in a longitudinally extending slot  60  of a longitudinally extending crank arm  62 , which is rigidly secured at its forward end to a transverse rotatable drive shaft  64  mounted to the forward end of the seat frame  32 . 
   Referring to  FIG. 11 , the footrest end plates  27  have been moved to an intermediate position by the push shaft  56  moving forward (to the left as viewed in  FIG. 11 ) so the crank arm  62  and the drive shaft  64  are rotated about 10 degrees in a clockwise (as viewed in  FIG. 11 ) direction. This causes linkage  36  to pivot the slide plates about pivot pins  68  in a clockwise direction. 
   Referring to  FIG. 12 , further movement of the push shaft to the left (as viewed in  FIG. 12 ) rotates crank arm  62  and drive shaft  64  in a counter clockwise (as viewed in  FIG. 12 ) directions so the linkage  36  moves the side plates  27  (footrest) to the full up position where the footrest deployment lock  42  engages part of extending linkage  36  and locks that linkage and the side plates in the up position. 
   Referring to  FIG. 13 , further movement of the linear actuator  50  to the left (as viewed in  FIG. 13 ) moves the push shaft and roller forward in the slot of the crank arm, causing the crank arm and drive shaft to rotate counterclockwise (as viewed in  FIG. 13 ) so that linkage  36  forces the slide frame  30  to move from the fully retracted position shown in  FIGS. 10-12  to the fully extended position shown in  FIG. 13 . 
   To return the footrest from the up and fully extended position shown in  FIG. 13  to the down and fully retracted position shown in  FIG. 10 , the linear actuator is operated to move it from left to right (as viewed in  FIGS. 10-13 ) so the retracting linkage  46 , which is described in more detail in  FIGS. 14-16 , restores the unit to the condition shown in  FIG. 10 . 
   Referring to  FIG. 14 , each slide plate  27  is rigidly secured at a respective rear portion to a respective end of a transverse footrest frame beam  70 . The rear end of each slide plate  27  is secured by a respective pivot pin  68  to the forward end of slide frame  30 . 
   As shown in  FIG. 14 , the slide plates are in the up position and the slide frame  30  is in the extended position with respect to seat frame  32 . The extending linkage  36  is locked in the up position by the footrest deployment lock  42 . The extending linkage includes an upwardly and forwardly extending drive arm  72  secured at its lower and rear end to the transverse rotatable drive shaft  64  ( FIG. 15 ) journaled in a pair of laterally spaced downwardly and forwardly extending drive shaft supports  74  secured at their upper end to a transverse member  76  of the seat frame. The forward and upper end of the drive arm  72  is pivotally secured by the transverse slide frame lock release shaft  44  to the lower end of an upwardly and forwardly extending longitudinal link  77 , the upper end of which is secured by a pivot pin  78  to the rear end of a longitudinally extending link  80 , the forward end of which is secured by a pivot pin  82  in a downwardly extending yoke  84  welded to the footrest frame beam  70  so that as the link  80  is moved longitudinally relative to the slide frame, the footrest frame beam  70  and side plates  27  are rotated about transverse pivot pins  68  secured to the forward end of the slide frame. The rear end of the footrest deployment lock  42  is welded to the forward end of link  77 . 
   The retracting linkage  46  includes a longitudinally extending link  86  secured at its forward end by transverse pivot pin  78  to the rear end of link  80 . The rear end of link  86  is secured by a transverse pivot pin  78  to a yoke  90  welded to a cross beam  92  of the slide frame. A pair of laterally spaced longitudinally extending tension springs (slide frame retract springs) are each connected at a respective forward end to the beam  92 , and at their respective rear end, to a transverse member  96  of the seat frame as shown in  FIG. 16 . 
   Thus, when the control is operated to retract the slide frame from the extended position shown in  FIG. 14 , the reversible motor of the linear actuator retracts the push shaft  52 . This rotates the drive shaft  64  and drive arm  72  in a clockwise (as viewed in  FIG. 16 ) direction. The upper end of the drive arm pulls links  77  and  80  rearwardly, thereby moving the slide frame  30  to the retracted position in the seat frame, which includes a stop (not shown) for limiting the inward travel of the slide frame relative to the seat frame. As the slide frame reaches the stopped (retracted) position, link  86  of the retracting linkage  36  forces pivot pin  78  downwardly, causing the footrest deployment lock  42  to move downwardly so the pivot pin  78  and the extending linkage is free to move downwardly so that further retraction of the linear actuator causes the link  80  to continue retracting and pivot the footrest frame beam  70  and side plates  27  in a counterclockwise position direction about pivots  68  until the footrest side plates are in the down position, that is, in the position shown in  FIG. 1A . To provide a smooth transition of the extending linkage from the locked to the unlocked position, a torsion spring (not shown) is connected between the pivot pin  78  and links  77 ,  80  and  86 . 
   The slide frame lock  38  (shown clearly in  FIG. 14 ) includes a pair of elongated laterally spaced and longitudinally extending pawls  100 . Each pawl is secured at a respective front portion by a separate transverse pivot pin  102  to the inner end of a respective transverse beam  104  of the seat frame, so each pawl is free to pivot about a respective transverse pivot pin  102 . The forward end of each pawl extends a substantial distance beyond its respective pivot pin  102 . Therefore, each pawl tends to pivot in a counterclockwise direction about its respective pivot point (as viewed in  FIG. 14 ). This causes the forward end of each slide frame lock bracket pawl  100  to rest on the slide frame lock release shaft  44  when the unit is operated to move the slide plates from the down position toward the up position. When the extending linkage is operated so the slide plates are in the down position (shown in  FIG. 1A ), the extending linkage is in the condition shown in  FIG. 15 , i.e., with a linear actuator fully retracted so the drive shaft is rotated to carry the drive arm  72  and the slide frame lock release shaft  44  to the position shown in  FIG. 15 . The permits each pawl  100  to pivot in a counterclockwise direction (as viewed in  FIG. 15 ), so the forward end of each pawl bears upwardly against the underside of transverse beam  92  of the slide frame. An upwardly extending projection  110  on each pawl fits against the forward face of transverse beam  92 , so the slide frame is locked against forward movement from the fully retracted position until the drive shaft rotates sufficiently to carry the slide frame lock release shaft  44  upwardly to engage the underside of each pawl, and pivot each pawl in a clockwise direction (as viewed in  FIGS. 14 and 15 ), so the upwardly extending projection  110  at the forward end of each pawl, will no longer interfere with the forward movement of the slide frame relative to the seat frame. With each pawl in the locking position, the slide frame cannot move forward, and the side plates of the footrest frame are locked in whatever intermediate position is set by the control. Thus, even though the slide frame is not extended, the footrest can be inclined at any desired position and held there by the action of the slide frame lock. 
   As the extending linkage is operated to move it toward the locked position shown in  FIG. 14  (and before the slide frame moves forward), the footrest locking bracket  42 , locks the extending linkage in the locked position shown in  FIG. 14  just as the slide frame lock release shaft lifts the forward end of each pawl to release the slide frame for forward movement in response to further actuation by the linear actuator. Thereafter, as the linear actuator continues to rotate the drive shaft in a counterclockwise direction (as viewed in  FIG. 16 ), the slide frame is free to move forward from the retracted to the extended position, where it is stopped by the gear drive in the linear actuator reaching the extended limit. In retracting the slide frame to the retracted position in the seat frame, the linear actuator and associated linkages move the slide frame as previously described until it engages the stop (not shown) on the seat frame. Further retraction of the linear actuator and push shaft causes the extending linkage to unlock and permit the footrest side plates to be moved to the down position. 
     FIGS. 17-20  show various ways for powering the drive shaft  64 . Referring to  FIG. 17 , the linear actuator  50  reciprocates a tooth rod drive shaft  120  to rotate a drive gear  122  and drive shaft  64  in either a clockwise or counterclockwise direction. 
   Referring to  FIG. 18 , the linear accelerator turns a worm gear  124 , which rotates a drive gear  126  and drive shaft  64  in either a clockwise or counterclockwise direction. 
   In the embodiment shown in  FIG. 19 , the linear accelerator operates a gear reduction drive  128  to rotate a drive sprocket  130  in either a clockwise or counterclockwise direction. A chain  132  connects the drive sprocket to a driven sprocket  134  which turns drive shaft  64  in either a clockwise or counterclockwise direction. 
   The embodiment shown in  FIG. 20  is similar to that previously described in detail above, and which the linear accelerator  50  reciprocates push shaft  56  to reciprocate crank arm  62  and turn drive shaft  64  in either a clockwise or a counterclockwise direction.