Photographic film pack easily checked whether suitable for use - has internally moulded-in lugs on front cover, one being easily detected as permanently bent if it has been heated during previous use

摘要

The pack for a film including a lens contains a roll of photographic film and has a means of exposing the film; it has at least two components made of plastics. The package has at least one projecting lug which is one-piece with the first component and which meets the second component; it is elastically deformed by the second component if the two components are assembled together so that they can be separated; the lug is used to ascertain if at least the first component is suitable for re-use, if it elastically recovers its original shape, if the components are separated, and whether at least the first component is not suitable for re-use because of permanent damage which arose in service. The plastic components are pref. made of polystyrene. ADVANTAGE - The design allows easy inspection and hence indication whether the package is fit for further use. This is done by checking whether the lug has been deformed by heat and, if so, by how much. This checking is aided if a reference lug is made also for comparison.