Capsules for containing coffee or another substance from which a beverage can be extracted using hot water

Abstract

A capsule for use in a coffee extraction machine has a frustoconical side wall, a transverse base closing one end of the side wall, an open mouth at the end remote from the base and a peripheral flange encircling the open mouth. A section of the side wall of the capsule close to the flange is thicker than the remainder of the side wall.

1 . A capsule for use in an extraction machine, the capsule having a frusto-conical side wall, a transverse base closing the smaller end of the capsule, an open mouth at the end of the capsule remote from the base and a peripheral flange encircling the open mouth of the capsule, characterised in that the side wall of the capsule is thickest over that section thereof which is closest to the flange, there being a single circumferentially extending sealing rib protruding from said flange in the direction towards the smaller end of the capsule and a circumferentially extending channel between said rib and said section. 
     
     
         2 . A capsule as claimed in  claim 1 , wherein the outer surface of the capsule's wall has a first step in it at which the conical angle increases and a second step spaced axially towards the flange from the first step at which the conical angle decreases thereby to form a shoulder between said steps which has a circumferentially extending skew surface. 
     
     
         3 . A capsule as claimed in  claim 2 , wherein the outer surface of the capsule is cylindrical between the skew surface and the flange. 
     
     
         4 . A capsule as claimed in  claim 2 , and including a circumferentially extending sealing rib protruding from said flange in the direction towards the smaller end of the capsule, the rib being of triangular cross section with its base integral with the flange and having an apex which, in use, is crushed by the leading end of the pressing sleeve. 
     
     
         5 . A capsule as claimed in  claim 1 , in which the conical angle of the outer surface of the side wall, over said section, is greater than the conical angle of the inner surface of said side wall over said section whereby said inner and outer surfaces diverge in the direction towards the flange and the wall thickness increases in the direction towards the flange. 
     
     
         6 . A capsule as claimed in  claim 5 , and including a circumferentially extending sealing rib protruding from said flange in the direction towards the smaller end of the capsule, there being a circumferentially extending generally U-shaped channel between said rib and said section for receiving the leading end of the pressing sleeve. 
     
     
         7 . A capsule as claimed in  claim 3 , and including a circumferentially extending sealing rib protruding from said flange in the direction towards the smaller end of the capsule, the rib being of triangular cross section with its base integral with the flange and having an apex which, in use, is crushed by the leading end of the pressing sleeve.