GB190907729A - Improvements in Printing Frames. - Google Patents

Abstract

7729. D÷rrstein, K., and Zimmermann, H. March 31. Contact printing-frames.-In a contact print ing-frame, the pressure clamping-device comprises two spring bars having means at one end for holding the edges of the negative and paper and preventing relative movement when examining the print, and at the other end means which can be adapted either for obtaining pressure on the back or for holding the back open. Two pins n near the ends of the spring bars m, Figs. 1 and 2, project into the space between the back p and the frame a, and press yieldingly on the edge of the negative and paper. The spring bars m also carry at this end a bail r, which projects above the front of the frame, and by means of which the pins n are released from pressing on the paper. At the opposite end the spring bars m bear on eccentrics or cams e on the rod d carrying the arm f, to which the back p is attached. In the closed position shown in Fig. 2, the spring bars press the eccentrics to increase the pressure, while in the open position they hold the frame open. The back is yieldingly connected to the arm f by a screw h, which passes freely through a ball-like projection i on the arm, whereby the back accommodates itself to the thickness of the negative and paper. A pin k limits the movement of the back on the pivot h. The negative or supporting-plate s is held in position between the end of the frame a and a spring-pressed sliding bolt b. A supporting-strut l is pivoted on the arm f to support the frame in an oblique position.