Base assembly for office chair

Abstract

A base assembly of an office chair includes a mounting member, multiple extensions and a bottom disk. The mounting member has multiple installation slots located evenly along the periphery of the mounting member. Each extension has a connection member at the first end thereof so as to be engaged with the installation slot corresponding thereto. The bottom disk is located at the underside of the first end of each of the extensions and has multiple holes and a central hole. Bolts extend through the holes and are connected to the underside of the mounting member to position the first ends of the extensions.

What is claimed is: 
     
         1 . A base assembly comprising:
 a mounting member having multiple installation slots which are located evenly along a periphery of the mounting member, a positioning hole defined centrally in the mounting member and a shaft inserted in the positioning hole;   multiple extensions each having a connection member connected to a first end thereof, the connection member being engaged with the installation slot corresponding thereto, and   a bottom disk located at an underside of the first end of each of the extensions and having multiple holes, bolts extending through the holes and being connected to an underside of the mounting member to position the first ends of the extensions.   
     
     
         2 . The base assembly as claimed in  claim 1 , wherein the underside of the mounting member has multiple threaded holes which are located alternatively relative to the installation slots and defined in a solid material of the mounting member, the installation slots each are a T-shaped hole which has an opening and a curved recess, two sides of each opening are solid walls, the connection member of each of the extensions is a T-shaped member and has a narrowed neck and a plate extending from two sides of the neck, the bottom disk has multiple protrusions which are located alternatively relative to the holes. 
     
     
         3 . The base assembly as claimed in  claim 1 , wherein a cap is connected to a top of the mounting member and has a passage defined centrally therethrough, the cap has multiple concavities and insertions on an underside thereof, the mounting member has multiple threaded holes defined in an underside thereof and the threaded holes of the mounting member are located alternatively relative to the installation slots, each installation slot has an opening and a curved recess, two sides of the opening are solid walls, the mounting member has recesses and blocks formed in an inner periphery thereof, the blocks are engaged with the concavities, the insertions are engaged with the recesses, the connection members of the extensions each have a narrowed neck and a plate extends from two sides of the neck, the plates are larger than the connection members and are engaged with the curved recesses of the installation slots. 
     
     
         4 . The base assembly as claimed in  claim 3 , wherein the cap has a bottom ring extending from the underside thereof, the bottom disk has a top ring extending from a top thereof, the bottom ring is engaged with notches in respective tops of the necks of the connection members of the extensions, the top ring is engaged with notches in respective bottoms of the necks of the connection members of the extensions.