Chair

Abstract

A chair is provided with a seat, a chair back control unit, a chair back, and two armrest units. The chair back is pivotally coupled to the seat by sleeving the engaging portions of the seat onto the clamp members of the chair back. The assembling of the chair back onto the seat can be easily done by the actions of inserting and clamping, so that the assembly operation is quick and easy without using any screws, and therefore the assembly cost is reduced. Furthermore, the angle and height of the armrest units can be easily adjusted, and the chair back is foldable. With the abovementioned structural arrangements, the number of the parts of the chair is substantially reduced.

What is claimed is: 
     
         1 . A chair comprising:
 a seat provided at two opposed sides thereof with an engaging portion which is a hollow cylindrical structure, each of the engaging portions being provided with two slots; and   a chair back with two opposed arm portions, each of the arm portions including a clamp member which is cylindrical structure formed with an annular groove around an outer peripheral surface thereof; the clamp members of the arm portions being inserted in the engaging portions of the seat and fixed therein by two elastic fixing members in such a manner that the annular grooves of the clamp members are aligned to the slots of the engaging portions, each of the elastic fixing members being provided with a clamp notch for clamping the engaging portions and two clamp sections which are inserted through the slots and into the annular grooves of the clamp members.   
     
     
         2 . The chair as claimed in  claim 1 , wherein the elastic fixing members are U-shaped. 
     
     
         3 . The chair as claimed in  claim 1 , wherein the seat is provided with a seat frame connected to a base, the seat frame is provided for mounting a seat cushion, the chair back includes a back frame with the two opposed arm portions, and the back frame is provided for mounting a back cushion. 
     
     
         4 . The chair as claimed in  claim 3 , wherein the seat frame is formed with an opening, the back frame is provided with a stop piece, the seat includes a chair back control unit which includes a rotary member rotatably disposed on the seat frame, a periphery of the rotary member includes an arc-shaped engaging edge and a disengaging edge which are alternatively inserted into the opening of the seat frame, when the arc-shaped engaging edge of the rotary member of the chair back control unit inserts into the opening, it will be stopped against the stop piece to stop the chair back from rotating, and when the disengaging edge of the rotary n ember inserts in the opening, the rotary member won't be in contact with the stop piece, so as to allow the chair hack to rotate. 
     
     
         5 . The chair as claimed in  claim 4  wherein the seat frame is provided with a through hole, the rotary member includes an assembling portion d is mounted on the control platform in such a manner that the assembling portion is aligned to the through hole of the platform, the chair back control unit includes a control button which is provided with an assembling section on one surface and a control section on another surface thereof, the assembling section is inserted into the through hole of the frame and fixed to the assembling portion of the rotary member, so that the control section of the control button is allowed to be rotated by a user, rotating the control button can drive the rotary member to rotate, so as to change a position of the rotary member with respect to the opening. 
     
     
         6 . The chair as claimed in  claim 5 , wherein there is a horizontal distance between the opening and the through hole, a periphery of the rotary member includes an arc-shaped engaging edge and a disengaging edge a direction extending from the disengaging edge through the assembling portion to the arc-shaped engaging edge is defined as a longitudinal axis which is perpendicular to the disengaging edge and consists of a first axis section and a second axis section, the first axis section is a distance between the disengaging edge and the assembling portion, and the second axis section is a distance between the assembling portion and the arc-shaped engaging edge, a length of the first axis section is equal to a length of the horizontal distance and less than a length of the second axis section. 
     
     
         7 . The chair as claimed in  claim 5 , wherein the seat is provided with a seat frame connected to a base, the seat frame includes a top surface and a bottom surface which is connected to the base, on the top surface of the seat frame is provided a control platform which is formed with the through hole and two opposed semicircular positioning protrusions, the opening is located adjacent to the control platform, the rotary member is provided with two opposed arc-shaped positioning cavities around a periphery thereof, and the two arc-shaped positioning cavities are aligned to the two positioning protrusions. 
     
     
         8 . The chair as claimed in  claim 1 , wherein an armrest unit is disposed at each of the arm portions, the arm portions are hollow structures and each provided with a receiving chamber and an inserting hole running through the receiving chamber, each of the armrest units includes a bottom cover, an elastic engaging member, a pin, a stop member, a spring, a control member and a top cover;
 the bottom cover includes a seat portion, a penetrating hole which is formed on the seat portion and penetrates the bottom cover, t  . o positioning protrusions, and a lateral hole, the penetrating hole is aligned with a corresponding one of the inserting holes;   the pin is provided with an inner hole and an annular positioning groove which is located at one end of the pm, the inner hole is formed with t  , o stop rotation grooves, the stop member is C-shaped and positioned in the annular positioning groove, the pin is inserted from the penetrating hole of the bottom cover through the inserting hole of the arm portion and finally into the receiving chamber, and the stop member stops against the seat portion to prevent the pin from sinking into the seat portion;   the control member includes two elongated holes and a control protrusion at one side thereof and a stop rotation block at another side thereof, the stop rotation block is configured to fit the shape of the stop rotation grooves, the control protrusion is provided at a surface thereof with a receiving groove which is located toward the stop rotation block, the control protrusion of the control member is inserted in the bottom cover and exposed out the bottom cover, the spring has one end received in the receiving groove and another end abutted against the seat portion of the bottom cover, the positioning protrusions of the bottom cover are inserted in the elongated holes of the control member, and the stop rotation block is inserted through the inner hole and into the stop rotation grooves of the pin; and   the top cover is mounted on the bottom cover.   
     
     
         9 . The chair as claimed in  claim 8 , wherein each of the armrest units includes an elastic engaging member, on an inner surface of the receiving chamber of each of the arm portions is formed a guiding block which is provided with a plurality of slanting grooves,
 on an outer surface of the pin is formed a swing slot which includes two slanting surfaces, the pin further includes an inserting groove in communication with the swing groove, the elastic engaging member includes a middle section, and a first engaging section and a second engaging section at two ends of the middle section, respectively, the elastic engaging member is fixed on the pin in such a manner that the middle section is received in the swing groove, and the second engaging section is received in the inserting groove.