Exercise chair

Abstract

An exercise chair includes a seat assembly, a backrest, a movable supporting member, a position-limiting device, and a resilient position-restoring element. The backrest is pivotally connected to a pivotal connection portion of the seat assembly. The movable supporting member includes a roller for contact with the ground and is pivotally connected to the backside of the backrest. When the tilted state of the backrest is changed, the movable supporting member changes the position at which the ground is in contact with the roller, lest the exercise chair tip over backward. The position-limiting device is connected between the pivotal connection portion and the movable supporting member to adjust and limit the aforesaid contact position. Should the position-limiting device fail, a second position-limiting device provided on the backrest can prevent the exercise chair from falling backward. The resilient position-restoring element helps restore the exercise chair to its most compact configuration.

What is claimed is: 
     
         1 . An exercise chair, comprising:
 a seat assembly provided with a pivotal connection portion;   a backrest pivotally connected to the pivotal connection portion and hence rotatable with respect to the seat assembly to change a tilted state of the backrest;   a movable supporting member having an end provided with at least one roller, the at least one roller being configured for contact with a ground, the movable supporting member having an opposite end pivotally connected to a backside of the backrest so that when the tilted state of the backrest is changed, the movable supporting member changes a position at which the ground is in contact with the at least one roller;   a position-limiting device connected between the pivotal connection portion and the movable supporting member to adjust and limit the position at which the ground is in contact with the at least one roller of the movable supporting member, and to adjust and limit a tilt angle of the backrest; and   a second position-limiting device provided on a second extension portion of the backrest to prevent the at least one roller of the movable supporting member from moving rearward excessively should the position-limiting device get loose, fall off, or break, lest the exercise chair tip over backward.   
     
     
         2 . The exercise chair of  claim 1 , further comprising at least one resilient position-restoring element, wherein the at least one resilient position-restoring element is connected between the backrest and the seat assembly in order to keep the backrest at a predetermined said tilt angle with respect to the seat assembly when no external force is applied to the backrest. 
     
     
         3 . The exercise chair of  claim 1 , wherein the backrest is provided with a plurality of rotatable foam elements. 
     
     
         4 . The exercise chair of  claim 1 , wherein the backrest has a convex front side. 
     
     
         5 . The exercise chair of  claim 1 , further comprising a headrest connected to the backrest. 
     
     
         6 . The exercise chair of  claim 1 , wherein the seat assembly has two lateral sides each provided with an armrest.