Ice chest having extending wall for variable volume

An icebox comprising:

• an icebox body (100) having a bottom (101) and side walls (103), which are filled with insulating material (10), and a storing part (107) opened at one side for storing foods within the storing part;
• a cover (300) for selectively opening and closing the opened side of the icebox body (100), the cover (300) having a receiving part (310);
• a capacity varying part (400) interposed between the icebox body (100) and the cover (300) and slidably joined to the storing part (107) so as to vary the capacity of the storing part (107), the capacity varying part (400) having an inside communicating with the storing part (107) of the icebox body (100) and including:
• a seating portion (410) seated on an upper face of the side walls (103) of the icebox body (100);
• and lifting frames (420) bent and extending from the seating portion (410) toward the storing part (107) and having side wall receiving portions (423) for receiving the side walls (103) when they are slidably joined to the icebox body (100);
• and
• at least one fastener (430) disposed on an outer circumferential surface of the lifting frames (420) of the capacity varying part (400), the at least one fastener protruding outwardly and having a plurality of fastening slots (433),
• wherein separation portions (109) are formed along the upper faces of the side walls (103) of the icebox body (100), and have a predetermined depth toward the bottom (101) so that the lifting frames (420) of the capacity varying part (400) can be slidably joined to the side walls,
• wherein a guide groove (120) is formed on the side walls (103) at a position corresponding to each at least one fastener (430), and communicates with the separation portions (109) so that the at least one fastener (430) is slidably inserted when the lifting frames (420) is joined, and
• wherein a position determining pin (130) is slidably arranged in the guide groove (120) and fit into the fastening slots (433) of the fastener (430), the position determining pin sliding along the guide groove (120) to maintain a position of the lifting frames (420).