GB676458A - Improvements in or relating to devices for forming and projecting a line of light - Google Patents

Abstract

676,458. Optical-projection apparatus. BEST, C., and MOLINS MACHINE CO., Ltd. Dec. 28, 1950 [Dec. 29, 1949], No. 33241/49. Class 97 (i). [Also in Group XI] In a projector comprising an electric lamp with a straight filament and a lens system whereby an image of the filament is formed on a line of light, an image of which is formed at a desired position by lenses with or without prisms, the support for the lamp comprises a bracket rotatable about the optical axis of the projector and means for swinging the bracket about an axis transverse to the optical axis whereby the filament may be aligned with the slit and an image of the filament and of its real image formed by a concave reflector located behind the lamp, be brought to coincide on the slit. The projected beam may be used to facilitate the observation of the movements of instruments for example by reflection in a movable mirror, and may be applied to the device described in Specification 647,029, [Group XL (b)]. The apparatus described comprises a tube 1 containing a slit diaphragm 6 on which an image of the filament is formed by a condenser 5, and an image of which is projected by a lens 7 and prism 9. The condenser is carried by a tube 13 slidable within the tube 1 and carrying a flange 12 from which project studs 11, Fig. 7, supporting the concave reflector 4 adjustable axially by screwing into a plate 10. The mirror 4 and condenser 5 may thus slide axially together. Rotatably supported on the tube 1 is a ring 22, Fig. 3, supporting pivots 19, 20, Fig. 6, having an axis transverse to that of the tube 1. On these pivots is a stirrup-shaped member 18 to which is fixed a bar 17 having secured thereto the lamp 3. The ring 22 has an abutment 24 held against an adjusting screw 23. Thus, rotation of the lamp about the optical axis is effected by the screw 23, rotation about the transverse axis of the pivots 19, 20 is effected by a screw 25, Figs. 6, 7, on the member 18 engaging a plate 26 fixed to the tube 1, and a screw 21 effects transverse movement of the lamp along the axis of the pivots 19, 20. By these adjustments the images of the filament 3 are formed on the slit in the diaphragm 6. The prism 9 is held in place against a machined seating by tubes 31, 32, the former having diametrical lugs 34 engaging slots 33 in a sleeve 30 screwed into the tube 1 and pressing the prism against a gasket 29. A rubber dustexcluding washer 35 may be provided.