Abstract: A pair of masks are mounted in front of a camera lens, one mask adjacent the lens and the other an adjustable distance in front of the first mask. The masks permit light to be transmitted through only a predetermined portion of the lens during each exposure so that only a corresponding portion of the film frame is exposed. The distance between the outer mask and the lens is adjusted according to the focused position of the lens when a zoom lens is employed to obviate overlapping of adjacent images on the film. The mask adjacent the lens opening is used with a conventional lens for forming four exposures in different areas of a single film frame.

Abstract: The holder is intended for fixed application to the tail stock of a lathe, or equivalent machine tool, to optionally mount a die or tap for externally or internally threading a workpiece carried on the rotating head-stock end of such machine tool. Thus mounted and adjustably pre-set, the holder automatically decouples operationally from the workpiece after a predetermined axial length of threading has been cut on the work part, thus causing the latter to rotatively overrun the tap or die on the holder.

Abstract: A device or attachment is disclosed which is adapted to be mounted upon a modern day camera, ordinarily a hand-held type, which enables the production on a single print of a number of different images of many different types, multichromatic or monochromatic, these images, two or four in number, being exposed successively on different, usually equal areas of a film frame. The device comprises an adapter ring in the form of a well-finished, split circular aluminum casting which is semi-permanently but removably mounted to the cylindrical lens mounting housing of the camera. This adapter has concentrically and rotatably mounted thereon a support plate for an opaque mask-carrying slide unit, the latter being equipped with a spring urged ball detent means enabling a special mask of the unit to be selectively indexed rotatably by the user into different positional settings, for example, two or four.