Multi-directional body motion stack chair

Abstract

The present invention comprises a chair that allows small, subtle multi-directional motion by the user while maintaining the functionality and space requirements of a stack chair. The chair of the present invention comprises motion that is facilitated by flexible supports mounted to the frame of the chair which suspend and support the chair's seat. A range of motion in the seat is thereby provided which is limited by integrated stopping mechanism built into the chair's frame. Allowing the user to change seating attitude with concomitant motion of the chair seat improves user comfort and prevents or delays user fatigue during long seating sessions while maximizing efficiency of work accomplished during a seating session.

What is claimed is: 
     
         1 . A stackable chair comprising:
 an upper section comprising a chair seat having a center;   a lower section in operative communication and connection with the upper section; and   a plurality of shock absorbing elements operationally interposed between the upper section and the lower section, each of the plurality of shock absorbing elements in operative communication and connection with the upper section and with the lower section and further comprising an uncompressed height and wherein each one of the plurality of shock absorbing elements is capable of independent compression in response to pressure changes on the chair seat whereupon a compressed height is achieved by at least one of the plurality of shock absorbing elements that is lower than the uncompressed height.   
     
     
         2 . The stackable chair of  claim 1 , wherein the upper section comprises:
 a chair seat having seat base having an upper side and a lower side; and   an upper seat plate in fixed secured connection with the lower side of seat base;   
     
     
         3 . The stackable chair of  claim 1 , wherein the chair seat further comprises an upper portion, wherein the upper portion and seat base are formed as a unitary structure. 
     
     
         4 . The stackable chair of  claim 1 , wherein the lower section comprises:
 a frame comprising a front pair of chair legs, a rear pair of chair legs and a lower base plate having a bottom side and cutout therethrough, the cutout having a profile and shape, the base plate in fixed attachment with the front and rear pairs of chair legs;   a rocker stop bracket in operative connection and communication with the cutout of lower base plate, rocker stop bracket further comprising side flanges that engage the bottom side of lower base plate, a vertical central section located between and adjacent the side flanges, the vertical central section comprising a profile that is complementary to the profile of base plate cutout, wherein the vertical central section engages and extends through the complementarily shaped cutout in lower base plate when side flanges engage the bottom side of lower base plate.   
     
     
         5 . The stackable chair of  claim 4 , wherein the lower section further comprises:
 a bottom cover in operative communication with lower base plate; and   a plurality of stack bumpers in operative communication with the bottom cover.   
     
     
         6 . The stackable chair of  claim 4 , wherein the bottom cover further comprises upwardly facing side flanges. 
     
     
         7 . The stackable chair of  claim 4 , further comprising a protective shroud  500  disposed between the upper seat plate and lower base plate wherein the protective shroud comprises side flanges. 
     
     
         8 . The stackable chair of  claim 4 , further comprising each leg of the front and rear pairs of legs comprising a distal end where a swivel glide is attached. 
     
     
         9 . The stackable chair of  claim 4 , wherein the plurality of shock absorbing elements comprise a plurality of compressible rubber bushings having a body with a diameter. 
     
     
         10 . The stackable chair of  claim 9 , wherein each of the plurality of compressible rubber bushings further comprise an upwardly facing nipple rising generally vertically above the body of the compressible rubber bushing, the nipple having a diameter that is less than the diameter of the rubber bushing's body, and a shoulder adjacent the nipple. 
     
     
         11 . The stackable chair of  claim 9 , wherein each of the plurality of compressible rubber bushings comprise a threaded hole in the nipple and a threaded hole in the body, wherein the nipple aligns with and engages a predrilled hole through the upper seat plate, wherein a fastener secures the upper seat plate to the threaded hole in the nipple and wherein the shoulder of the compressible rubber bushing engages the bottom surface of upper seat plate. 
     
     
         12 . The stackable chair of  claim 11 , wherein the body of each of the plurality of compressible rubber bushings comprises a threaded hole therein, each threaded hole in alignment with a predrilled hole in the lower base plate, wherein a fastener secures the body of the compressible rubber bushing to the lower base plate. 
     
     
         13 . The stackable chair of  claim 11 , further comprising a gap established between the upper section and the lower section of the chair, wherein the gap corresponds to the height of the body of the bushings. 
     
     
         14 . The stackable chair of  claim 11 , wherein the preferred complementary profiles for the base plate cutout and the rocker stop bracket is rectangular. 
     
     
         15 . The stackable chair of  claim 1 , wherein the plurality of stock absorbing elements comprise air shock absorbers. 
     
     
         16 . The stackable chair of  claim 1 , wherein the plurality of shock absorbing elements comprise springs. 
     
     
         17 . A stackable chair comprising:
 a chair seat having seat base having an upper side and a lower side;   an upper seat plate in fixed secured connection with the lower side of seat base;   a frame comprising a front pair of chair legs, a rear pair of chair legs and a lower base plate having a bottom side and cutout therethrough, the cutout having a profile and shape, the base plate in fixed attachment with the front and rear pairs of chair legs;   a rocker stop bracket in operative connection and communication with the cutout of lower base plate, rocker stop bracket further comprising side flanges that engage the bottom side of lower base plate, a vertical central section located between and adjacent the side flanges, the vertical central section comprising a profile that is complementary to the profile of base plate cutout, wherein the vertical central section engages and extends through the complementarily shaped cutout in lower base plate when side flanges engage the bottom side of lower base plate;   a bottom cover in operative communication with lower base plate;   a plurality of stack bumpers in operative communication with the bottom cover;   a plurality of independently compressible rubber bushings having a body with a diameter, wherein each of the plurality of compressible rubber bushings further comprise an upwardly facing nipple rising generally vertically above the body of the compressible rubber bushing, the nipple having a diameter that is less than the diameter of the rubber bushing's body, and a shoulder adjacent the nipple,   wherein each of the plurality of compressible rubber bushings further comprise a threaded hole in the nipple and a threaded hole in the body, wherein the nipple aligns with and engages a predrilled hole through the upper seat plate, wherein a fastener secures the upper seat plate to the threaded hole in the nipple and wherein the shoulder of the compressible rubber bushing engages the bottom surface of upper seat plate,   wherein the body of each of the plurality of compressible rubber bushings comprises a threaded hole therein, each threaded hole in alignment with a predrilled hole in the lower base plate, wherein a fastener secures the body of the compressible rubber bushing to the lower base plate; and   a gap established between the upper seat plate and lower base plate, wherein the gap corresponds to the height of the body of the bushings   
     
     
         18 . A method for providing a chair with a base that moves in response to a user's shifting weight, comprising:
 providing a chair with an upper section comprising a chair seat having a center and an upper seat plate fixed to the chair seat;   providing a chair with a lower section comprising a frame having legs and a lower base plate, wherein the upper section and the lower section are in operative communication and connection;   providing a plurality of shock absorbing elements interposed between the upper section and the lower section, whereupon the upper section is suspended.   
     
     
         19 . The method of  claim 18 , wherein each of the plurality of shock absorbing elements compress substantially equally when the user's center of mass is substantially centered on the chair seat. 
     
     
         20 . The method of  claim 19 , wherein at least one of the plurality of shock absorbing elements compressing more than the other of the plurality of shock absorbing elements in response to a shifting of the user's center of mass away from the substantial center of the chair seat.