GB891228A - Diapositive frame - Google Patents

Abstract

891,228. Transparency frames. RIEDEL, H. Sept. 2, 1958 [Sept. 3, 1957; March 25, 1958], No. 28175/58. Class 98(2). In a transparency frame in which cover-glasses are located in a frame member and secured by a cover member having runners engaging grooves in the frame member, the runners are resiliently inclined to the grooves so that the adjacent margins of the glasses are passed down by the overlying portions of the cover. As shown, when using two cover-glasses which are thinner than the average, only the outer longitudinal edge 30 of each runner 10 engages the groove in the frame member to exert pressure through overlying portion 29 on the film 31 and glasses. When thicker cover-glasses are used the overlying portions transverse to the runners may be bowed outwardly from the glasses. In another form, (Figs. 15-19, not shown) this tendency is overcome by giving the cover a cylindrical curvature in the opposite sense. A depression 33 enables catch 25 to be released by insertion of the finger-nail so that the cover may be slid off in the longitudinal direction of Fig. 11. The frame may be made of polystyrene having a titanium dioxide filter.