Interlocking arrangement for plastic containers

In a container system comprising a plurality of plastic containers of predetermined volumes, the system being suitable for storing chemicals and pouring said chemicals into a machine, the improvement which comprises:

• an interlock for snapping a first of said containers onto a second of said containers, the interlock comprising a male portion disposed on the first container and a female portion disposed on the second container, the female portion having a contour shaped to coincide substantially with the contour of the male portion, each part of the male portion having a counterpart in the female portion,
• the male portion comprising a curved protrusion and a tapered flange, the protrusion and the flange being adjacent to each other, and wherein the protrusion overhangs the flange,
• the curved protrusion comprising a curved surface and a straight surface, the surfaces intersecting at an acute angle and along a line spaced sufficiently away from the body of the container such that the curved protrusion can be hooked onto its counterpart in the female portion of the container,
• the tapered flange having a width which increases with the distance away from the curved protrusion, the width of the flange also increasing with the distance from the container, wherein the tapered flange on the male portion is capable of being snapped onto its counterpart in the female portion of the container,
• wherein the curved protrusion and the tapered flange are capable of being matably attached to their respective female counterparts.