Abstract: A photographic film unit, including a film disk carried on a hub, has a mass of firm material deposited between the disk and the hub so that the mass, rather than the dimensions of the respective parts, accurately determines the relative film-to-hub alignment. The hub initially fits loosely in a central film-disk aperture. The material, a thermo-plastic, is then melted ultrasonically to flow between the disk and the hub, eliminating the looseness, and maintaining the disk on the hub in accurate alignment. According to one disclosed embodiment, the thermoplastic material adheres a retainer ring to the hub with the film disk captured therebetween. The thermoplastic then fills the interstices between the ring, the hub, and the disk to exclude foreign matter, such as processing fluids.

Abstract: Ultrasonic method and apparatus having improved turn-on. Low level power is furnished to an unloaded transducer to start it running at a desired frequency. High level power is then furnished the transducer for performing the ultrasonic operation while loaded. The high level power is stopped and the low level power is maintained, reduced or stopped before the load is removed.