Patents Assigned to Bonum-Werk Inh. Friedrich Hetzmannseder
  • Patent number: 4104818
    Abstract: A slide frame is comprised of two component frames snapped together to clamp a slide film therebetween. The slide film has perforations on opposite sides thereof and arranged to extend along two opposite parallel sides of a window defined by the slide frame, the perforations having edges remote from the parallel sides. Two film spreading bars are arranged between the joined component frames along the two opposite parallel sides for limited longitudinal displacement in the direction of the sides and each of the bars has teeth for interengaging with the perforations in the slide film. The spreading bars are held between the component frames with their teeth engaging the remote edges of the film perforations whereby the film is held under tension between the component frames.
    Type: Grant
    Filed: November 26, 1976
    Date of Patent: August 8, 1978
    Assignee: Bonum-Werk Inh. Friedrich Hetzmannseder
    Inventor: Heinrich Hrabik