Variable volume container

Abstract

A variable volume container, comprising: a lower portion comprising a base and four walls, the four walls extending from the base and comprising a lip at the top of the walls of the lower portion; and an upper portion comprising four walls, wherein opposing walls of the upper portion comprise one or more protrusions configured to abut the lip of the lower portion to allow the upper portion to rest upon the lower portion, to place the container in an extended position; and wherein the opposing walls of the upper portion comprising the one or more protrusions are configured to flex laterally, relative to the lip of the lower portion, to allow the one or more protrusions to be disengaged from the lip to allow the upper portion to be moved downwards relative to the lower portion, to place the container in a retracted position.

I/We claim: 
     
         1 . A variable volume container, comprising:
 a lower portion comprising a base and four walls, the four walls extending from the base and comprising a lip at the top of the walls of the lower portion; and   an upper portion comprising four walls, wherein opposing walls of the upper portion comprise one or more protrusions configured to abut the lip of the lower portion to allow the upper portion to rest upon the lower portion, to place the container in an extended position; and   wherein the opposing walls of the upper portion comprising the one or more protrusions are configured to flex laterally, relative to the lip of the lower portion, to allow the one or more protrusions to be disengaged from the lip to allow the upper portion to be moved downwards relative to the lower portion, to place the container in a retracted position.   
     
     
         2 . A variable volume container as claimed in  claim 1 , wherein the opposing walls of the upper portion comprising the one or more protrusions are configured to flex away from each other to allow the one or more protrusions to be disengaged from the lip. 
     
     
         3 . A variable volume container as claimed in  claim 1 , wherein the walls of the lower portion, corresponding to the opposing walls of the upper portion comprising the one or more protrusions, comprise a substantially wedge-shaped portion underneath the lip configured to force the opposing walls of the upper portion away from each other as the upper portion is moved upwards relative to the lower portion, from the retracted position, to allow the one or more protrusions to move past the lip. 
     
     
         4 . A variable volume container as claimed in  claim 1 , wherein two other opposing walls of the upper portion comprise one or more protrusions at their lower ends, the one or more protrusions configured to interact with a lower surface of the lip to retain the upper portion on the lower portion. 
     
     
         5 . A variable volume container as claimed in  claim 4 , wherein the one or more protrusions of the two other opposing walls of the upper portion comprise a substantially wedge-shaped portion configured to force the two other opposing walls of the upper portion away from each other as the upper portion is moved downwards relative to the lower portion, to allow the one or more protrusions of the two other opposing walls to move past the lip. 
     
     
         6 . A variable volume container as claimed in  claim 4 , wherein when the container is in the extended position, the one or more protrusions of the opposing walls abut the lip and the one or more protrusions of the other opposing walls are located underneath the lip. 
     
     
         7 . A variable volume container as claimed in  claim 4 , wherein the container is substantially rectangular in shape, the two opposing walls are the shorter sides of the rectangle and the two other opposing walls are the longer sides of the rectangle. 
     
     
         8 . A variable volume container as claimed in  claim 1 , comprising a lid configured to be positioned on the upper portion to close the container. 
     
     
         9 . A variable volume container as claimed in  claim 8 , wherein the lid is configured to be positioned on the lower portion, to close the lower portion. 
     
     
         10 . A variable volume container as claimed in  claim 8 , wherein the upper portion and/or lower portion comprise one or more features, and wherein the lid comprises one or more corresponding features to allow the lid to be positioned on the upper portion or lower portion. 
     
     
         11 . A variable volume container as claimed in  claim 8 , wherein the lid comprises one or more features configured to cooperate with one or more corresponding features of another similarly configured lid to allow the lids to be stacked. 
     
     
         12 . A variable volume container as claimed in  claim 1 , wherein the upper portion comprises one or more features configured to cooperate with one or more corresponding features of another similarly configured upper portion to allow the upper portions to be stacked. 
     
     
         13 . A variable volume container as claimed in  claim 1 , wherein the lower portion comprises one or more features configured to cooperate with one or more corresponding features of another similarly configured lower portion to allow the lower portions to be stacked. 
     
     
         14 . A variable volume container as claimed in  claim 1 , wherein the container comprises one or more features configured to cooperate with one or more corresponding features of another similarly configured container to allow the containers to be stacked. 
     
     
         15 . A variable volume container as claimed in  claim 1 , wherein at least one of the walls of the upper and/or lower portion comprises at least one external, recessed, substantially flat portion configured to receive at least one label. 
     
     
         16 . A variable volume container as claimed in  claim 1 , wherein the opposing walls of the upper portion that are configured to flex laterally comprise at least one external, substantially smooth area.