| 摘要 |
633,571. Lighting units. RITTER CO., Inc. July 17, 1947, No. 19190. Convention date, Aug. 1, 1946. [Classes 75 (ii), 75 (iii) and 75 (iv)] A lamp for dental and like purposes comprises a first light source having means for projecting the light in a concentrated beam and one or more fluorescent discharge tubes disposed around said first light source to provide a diffuse illumination. As shown, an incandescent light bulb 21 having a shield 31 to screen direct light rays, is mounted in front of a parabolic mirror 34 within a cylindrical casing 24, the bore of which is enlarged and shaped at the front end to house a lens 38 of heat absorbent material, retained by a snap ring 52. Symmetrically disposed around the outside of the casing 24 are three metal strip brackets 41 the ends 43 of which are bent to semi-circular form to seat two circular fluorescent tubes 44 side by side and concentric with the casing 24. White painted or polished metal conical reflectors 50 are disposed beneath the tubes 44. The tubes 44 are enclosed within a two-part ellipsoidal housing 46, 47 of transparent or translucent, glass or plastic material, mounted on the casing 24 by means of retaining rings 57 and 63 having a stud and helical groove attachment with said casing. The forward wall 71 of the casing 69 is turned inwardly to form an inner flat support portion 72, and has bent spring clips 73 to press the mirror 34 against an annular positioning abutment 33. Two brackets 76, Fig. 8, form a mounting for a pair of reactors 79 provided for the tubes 44. A semi-cylindrical recess 94 is formed in the support part 72 and co-operates with a member 96 to clamp a horizontal pivot pin 92 which is secured in the head of a goose-neck support post 84. The support post 84, which has an axial wiring bore 86 opening into the casing 69 as at 87, extends between the reactors 79 through a slot 83 in a rear casing cover 81 and is mounted on a hollow vertical pivot rod 89. The lighting unit is approximately in balance on its support pivot. Openings 101 in the casing wall allow wiring (not shown) to pass through to the tubes 44, and separate switches 106, 107 are provided for independent control of the bulb 21 and the tubes 44 respectively. In an alternative construction the circular fluorescent tubes may be of different diameters and arranged partially nested with respect to each other, thus allowing a reduction in the width of the two-part housing 46, 46. |
