Chair with flex member

Abstract

A chair includes a first side member, a second side member, a back cross member, a first flex member, and a second flex member. The first side member supports a first side of the chair and the second side member supports a second side of the chair. The back cross member is situated between the first side member and the second side member and rotates relative to the first side member and the second side member. The first flex member is coupled to the first side member and the back cross member and twists as the back cross member rotates relative to the first side member and the second side member. The second flex member is coupled to the second side member and the back cross member and twists as the back cross member rotates relative to the first side member and the second side member.

1 . A chair comprising:
 a first side member to support a first side of the chair on a surface;   a second side member to support a second side of the chair on the surface;   a first cross member situated between the first side member and the second side member, the first cross member being rotatable relative to the first side member and the second side member;   a first flex member coupled to the first side member and to the first cross member, the first flex member configured to twist as the first cross member rotates relative to the first side member and the second side member; and   a second flex member coupled to the second side member and to the first cross member, the second flex member configured to twist as the first cross member rotates relative to the first side member and the second side member.   
     
     
         2 . The chair of  claim 1 , wherein the first flex member is a first torsion spring that twists as the first cross member rotates relative to the first side member and the second side member and the second flex member is a second torsion spring that twists as the first cross member rotates relative to the first side member and the second side member. 
     
     
         3 . The chair of  claim 1 , wherein the first cross member has a cross member longitudinal axis and the first cross member rotates relative to the first side member and the second side member around the cross member longitudinal axis. 
     
     
         4 . The chair of  claim 3 , wherein the first flex member has a flex member longitudinal axis that is parallel with the cross member longitudinal axis and the first flex member twists around the flex member longitudinal axis as the first cross member rotates around the cross member longitudinal axis. 
     
     
         5 . The chair of  claim 1 , wherein the first flex member is attached to the first side member with a fastener and the first flex member twists around a flex member longitudinal axis of the first flex member that is parallel with a longitudinal axis of the fastener. 
     
     
         6 . The chair of  claim 1 , wherein at least one of the first flex member and the second flex member is made of at least one of rubber and polyurethane. 
     
     
         7 . The chair of  claim 1 , comprising:
 a chair back coupled to the first cross member and having a top that moves forward and backward as the first cross member rotates relative to the first side member and the second side member.   
     
     
         8 . The chair of  claim 1 , wherein the first flex member is attached to the first side member with at least one fastener, the first flex member engaging with the at least one fastener to prevent further rotation of the first cross member as the first cross member rotates relative to the first side member and the second side member. 
     
     
         9 . The chair of  claim 1 , wherein the first flex member is coupled to the first cross member by an attachment member, the first flex member engaging with the attachment member to prevent further rotation of the first cross member as the first cross member rotates relative to the first side member and the second side member. 
     
     
         10 . The chair of  claim 1 , wherein:
 the first side member comprises:
 a first leg; and 
 a second leg coupled to the first leg; and 
   the second side member comprises:
 a third leg; and 
 a fourth leg coupled to the third leg. 
   
     
     
         11 . The chair of  claim 1 , comprising:
 a second cross member coupled to the first side member and the second side member;   a seat support connected to the second cross member; and   a seat connected to the seat support to rotate between an up position and a down position, wherein the seat is supported by the second cross member for sitting on in the down position.   
     
     
         12 . The chair of  claim 1 , comprising:
 a first armrest coupled to the first side member; and   a second armrest coupled to the second side member.   
     
     
         13 . A chair comprising:
 a first side member to support a first side of the chair on a surface;   a second side member to support a second side of the chair on the surface;   a first cross member situated between the first side member and the second side member, the first cross member rotatable relative to the first side member and the second side member;   a first flex member secured to the first side member with at least one first fastener, the first flex member configured to deform to twist as the first cross member rotates relative to the first side member and the second side member, and the at least one first fastener to provide a first stop against the first cross member to prevent further rotation of the first cross member; and   a second flex member secured to the second side member with at least one second fastener, the second flex member configured to deform to twist as the first cross member rotates relative to the first side member and the second side member, and the at least one second fastener to provide a second stop against the first cross member to prevent further rotation of the first cross member.   
     
     
         14 . The chair of  claim 13 , wherein the first flex member is a first torsion bar that twists as the first cross member rotates relative to the first side member and the second side member and the second flex member is a second torsion bar that twists as the first cross member rotates relative to the first side member and the second side member. 
     
     
         15 . The chair of  claim 13 , wherein the first flex member twists along a longitudinal axis of the first flex member that is parallel with the longitudinal axes of the at least one first fastener. 
     
     
         16 . The chair of  claim 13 , wherein at least one of the first flex member and the second flex member is made of at least one of rubber and polyurethane. 
     
     
         17 . The chair of  claim 13 , comprising:
 a chair back coupled to the first cross member and having a top that moves forward and backward as the first cross member rotates relative to the first side member and the second side member.   
     
     
         18 . The chair of  claim 17 , wherein the first flex member is coupled to the first cross member by an attachment member that couples the chair back to the first cross member. 
     
     
         19 . A method of making a chair comprising:
 fastening a first flex member to a first side member;   fastening a second flex member to a second side member; and   securing a chair back to a first cross member, wherein securing the chair back to the first cross member couples the chair back to the first flex member and the second flex member.   
     
     
         20 . The method of  claim 19 , comprising:
 fitting a first portion of the first flex member into the first side member prior to fastening the first flex member to the first side member.   
     
     
         21 . The method of  claim 20 , comprising:
 fitting a second portion of the first flex member into the first cross member prior to securing the chair back to the first cross member.   
     
     
         22 . The method of  claim 19 , wherein fastening the first flex member comprises:
 bolting the first flex member to the first side member.   
     
     
         23 . The method of  claim 19 , comprising:
 attaching a second cross member to the first side member and the second side member; and   rotatably coupling a seat to the second cross member.   
     
     
         24 . A chair comprising:
 a base configured to support the chair on a surface, the base having a first side and a second side;   a seat maintained by the base;   a chair back having a reclined position and an upright position; and   a chair back flex assembly coupling the chair back to the base, the chair back flex assembly including:
 a cross member having a first end and a second end and a longitudinal axis; 
 a first flex member coupled to the cross member at the first end of the cross member such that the first flex member elastically deflects to permit rotation of the cross member about the longitudinal axis of the cross member as the chair back is moved from the upright position to the reclined position. 
   
     
     
         25 . The chair of  claim 24 , further comprising a second flex member coupled to the cross member at the second end of the cross member such that the second flex member elastically deflects to permit rotation of the cross member about the longitudinal axis of the cross member as the chair back is moved from the upright position to the reclined position. 
     
     
         26 . The chair of  claim 24 , wherein the first flex member is formed of a material having a durometer of 95 Shore A. 
     
     
         27 . The chair of  claim 24 , wherein the first flex member is formed of a substantially solid block of elastomeric material. 
     
     
         28 . The chair of  claim 24 , wherein the first flex member is coupled to the cross member by an attachment member, the first flex member engaging with the attachment member to arrest movement of the chair back beyond the reclined position. 
     
     
         29 . The chair of  claim 24 , wherein a portion of the first flex member is received within the cross member. 
     
     
         30 . The chair of  claim 24 , wherein the first flex member causes the chair back to return to the upright position from the reclined position.