Portable projector for transparencies - has battery operated lamp, film support slot and lenses housed in cylindrical telescopic hand-held casing

摘要

The projector for transparencies includes two hollow cylindrical parts (A, B). The first part (A) houses four electric batteries (10) connected in series. These are held in place by internal ribs (11) formed integrally with the housing. To allow the batteries to be inserted, this part of the housing is made as two half shells (12, 13) held together by spring clips. The lower shell (12) also supports a lamp bulb (15) fitted into a screw socket (16). Wires (17) connect the lamp to the batteries via a switch (18) mounted in the upper surface of the cylinder. A reflector (21) separates the lamp from the batteries. At one end of the lower shell (12) are two plano-convex lenses (22) with their convex surfaces facing each other. The first cylinder (A) ends with two longitudinal ribs (23), defining a slot into which the transparency may be inserted. The second cylinder (8) has an internal dia. slightly greater than that of the first cylinder so that it may slide over it. This part houses a biconvex lens projecting an image of the transparency on to a distant screen.