One-Piece Chair Backs and Chairs Having the Same

Abstract

A chair has a chair back including a frame, two supporting legs and a bearing plate. The frame is integrated to the supporting legs in an injection molding manner. The bearing plate is integrated to a bottom frame portion and two side frame portions of the frame in the injection molding manner so that a user can lean against the bearing plate. The two side frame portions are located on two opposite sides of the bottom frame portion. The hardness of the bearing plate is lower than the hardness of the frame, and the hardness of the frame is lower than the hardness of the supporting leg. Therefore, two members whose materials are different in hardness are possibly constitute a chair back formed in one piece.

What is claimed is: 
     
         1 . An one-piece chair back comprising:
 a frame including a bottom frame portion and two side frame portions respectively connected to two opposite sides of the chair back, and an accommodating space formed by the bottom frame portion and the two side frame portions;   two supporting legs connected to the frame by means of injection molding, and a hardness of the two supporting legs being higher than that of the frame; and   a bearing plate disposed in the accommodating space and connected to the two side frame portions and the bottom frame portion by means of injection molding, the bearing plate being configured for a user to rest against, and the bearing plate having a hardness lower than that of the frame.   
     
     
         2 . The one-piece chair back as claimed in  claim 1 , wherein the frame and the supporting legs are made of the same material but in different proportions. 
     
     
         3 . The one-piece chair back as claimed in  claim 1 , wherein a material of the frame includes nylon and glass fiber, and a content of the glass fiber is 7-30 weight percent. 
     
     
         4 . The one-piece chair back as claimed in  claim 1 , wherein a material of each of the supporting legs includes nylon and glass fiber, and a content of the glass fiber is 7-50 weight percent. 
     
     
         5 . The one-piece chair back as claimed in  claim 1 , wherein a material of the bearing plate is nylon or polyether-based thermoplastic polyurethane. 
     
     
         6 . The one-piece chair back as claimed in  claim 1 , wherein each of the side frame portions is provided with an extension portion facing a first inner side surface of the bearing plate, the extension portions extend in opposite directions, and each of two opposite second inner side surfaces of the bearing plate facing the side frame portions includes an indentation, the indentations are aligned with the extension portions, and positions of the extension portions and the indentations correspond to a position of the user's lower back. 
     
     
         7 . The one-piece chair back as claimed in  claim 6 , wherein the extension portions each include at least one first ventilation hole. 
     
     
         8 . The one-piece chair back as claimed in  claim 1 , wherein the bearing plate includes at least one second ventilation hole. 
     
     
         9 . The one-piece chair back as claimed in  claim 1 , wherein a fixing groove for insertion of a seat is recessed on an end surface of each of the supporting legs at one end thereof away from the frame. 
     
     
         10 . A chair, comprising the chair back as claimed in  claim 1 , and a seat connected to the supporting legs of the chair back.