Light-tight cassette

Claim 1

A light-tight cassette for holding and dispensing a roll of light-sensitive material, said cassette being in the form of a rectanguloid casing comprising a four-sided shell with end closure walls having central hub portions for rotatably supporting said roll within the casing, the shell having a peripheral exit slot through which light-sensitive material can be drawn from said roll and at least one of said end walls being formed by a separate end cap which has spaced inner and outer peripheral wall portions defining a peripheral groove for receiving the end margins of the shell to hold the cap in place thereon and at corner sections thereof has axially projecting guide tongues which when the cap is in place fit inside corner regions of the corresponding end of the shell and constitute extensions of the inner face of the inner wall of such peripheral groove, characterised in that each of said guide tongues has a three-dimensional configuration defining an outwardly facing surface which is outwardly convexly curved both in radial planes passing through the axis of its hub portion and in transverse planes normal to said axis whereby said guide tongues provide a self-centering effect when the cap and shell are pushed together in abaxial and/or relatively angularly skewed relationship.