Patent GB-824105-A (GB)
Title: Improvements in photographic type-composing machines
Inventor: CHEETHAM CLIFFORD
IPC: B41B17/02
Filed: 1955-09-09
Abstract: 824,105. Photographic type-composing. MINISTER OF AGRICULTURE, FISHERIES & FOOD. Dec. 7, 1956 [Sept. 9, 1955], No. 25826/55. Class 98(1) A photographic type-composing machine includes a frame bearing a line of characters and having a control line divided into portions each associated with a character, means for positioning the frame so that a selected character and its associated portion of the control line are in operating position, apparatus for exposing a film to the projected character, and a control member arranged to move at least through a distance determined by the position of the operating portion of the control line and by this movement to advance the film by a proportional distance for character spacing, half this movement being effected before an exposure and half after, the control member being stationary during exposure. As shown in Fig. 2, the characters are formed with an opaque background on a transparent plate 21, which is mounted in a frame 1 of "Duralumin" (Registered Trade Mark). The frame above each character is cut down from the edge by a distance proportional to the set width of the character. Several interchangeable plates carrying different founts may be used, and the frames may, for some applications, have two or three identical sets of characters arranged one below the other. The frame is mounted in the machine in a frame carrier 12, Fig. 1. A light beam from a source 3 is directed at an operating position 4 to which any character may be brought by longitudinal movement of carrier 12. For manipulation, a bar 13 is hinged to the carrier, and carries a claw 15 which engages any one of a set of studs 14 to locate the carrier with the selected character exactly in the operating position. The photographic action is initiated by a switch, actuated by the operator or by the bar 13 when it is lowered, which causes a condenser to discharge through a solenoid 16. A continuously running electric motor 10 drives a shaft 11 through gears 31, 32 and a slipping clutch 30, 41, 42. Normally a catch 18 engages a recess in a disc 19 mounted on shaft 11 and holds the shaft against movement, but operation of solenoid 16 disengages catch 18 momentarily to permit shaft 11 to rotate once. A rod 36 pivoted to a crank 35 on the shaft slides in an aperture 37 in a frame 38 pivoted about one side 43. At the beginning of the operation the frame is held in its highest position by a stop 45 on rod 36, and as shaft 11 rotates the frame descends until a shoulder 46, formed on a control member 7 integral with the frame, abuts the edge of the frame 1. This is arranged to occur after shaft 11 has completed not morethan <SP>1</SP>/ 3  of a revolution. For about another <SP>1</SP>/ 3  of a revolution of shaft 11 frame 38 remains in this position, the stop 45 being disengaged therefrom, and during the last <SP>1</SP>/ 3  of a revolution the frame is returned to its initial position. The control member 7 is connected to a rod 47 through a gear lever 48, pivoted at a point 49 which is adjustable to vary the amount of spacing according to the size of the projected character image. Rod 47 is connected to one end of a bar 8, pivoted at its mid-point 50 and linked at the other end to a pair of electro-magnetic gripping devices 53, 54 co-operating with a disc 9. By means of a commutator 33 mounted on shaft 11, the devices 53, 54 are alternately energized in the first and second halves respectively of each revolution of the shaft. Thus the upward and downward movement of the control member 7, which are proportional to the character width, produce proportionate rotations in the same direction of the disc 9. A carrier 6 for the film receiving the projected character images is moved in the image plane by a rod 57, to which is attached a wire passing around a driving wheel 56 connected by shaft 55 to disc 9. Since the exposure of the film occurs during the middle <SP>1</SP>/ 3  of the revolution of shaft 11, half the character spacing movement occurs before exposure and half after. Exposure is effected by a slotted plate 5 which slides across the image forming beam under action of a cam 34 mounted on shaft 11. The energization of the electro-magnetic gripping devices 53, 54 is normally effected by contacts X, Y arranged diametrically with respect to the commutator 33, which consists of a disc divided diametrically into conducting and non-conducting halves. The inter-character spacing can be reduced by bringing further contacts Y1, Y2 into the circuit. The film is carried on spools in carrier 6, and is wound on after each line is complete. If the character images are developed on transparent stripping film, a wax or adhesive may be applied and words cut out from the film and stuck to a map or plan where required, after which the map or plan is photographed. In a modification, the control member is formed with a narrow slit instead of shoulder 46. A light beam passing through the slit to a photo-electric cell beyond is cut off when the slit passes below the level of the edge of the frame 1, thus enabling the electro-magnetic gripping devices 53, 54 to be controlled by the photo-electric cell. In this case the control line, instead of forming the actual edge of frame 1, may constitute the boundary between transparent and opaque parts of the frame.