Patent GB-191105291-A (GB)
Title: Improvements in and relating to Photographic Printing Apparatus.
Inventor: HULL HENRY EDMONDS
IPC: G03B27/16
Filed: 1911-03-02
Granted: 1912-02-01
Abstract: 5291. Hull, H. E., and Adams, S. G. March 2. Printing - apparatus, rapid bromide and like. -The time of exposure is automatically regnlated by clock - work, which is wound up to a predeterminable extent each time the printing- frame is opened, and is released and d started when the printing-frame is closed. The red lamp 42, Fig. 1, and the printing-lamps 1 are alternately switched on and off. Separate terminals, controlled b y the clock-work index, are used for giving a prolonged exposure. The pressure board 5 is in two parts attached to an arched spring 8 on the arm 6. The frame is normally closed by the spring 9, and is opened by the treadle 10. The clock - work mechanism is controlled from the frame by an arm 12 on the arm 6 which actuates an arm 13 on the shaft 14, at the other end of which a similar arm rests upon two arms 18, 19, Figs. 3 and 4, of the clockwork mechanism. When the printing-frame is opened, the arm 12 releases the arm 13, and the spring 23 raises the lever 22 and an arm 24, which winds up the clock-work. The clock-work rotates an insulating-disk 25, and is wound until a pin 26 on the disk 25 is stopped by a stop 28 on the index-wheel 27, which is previously set for the exposure required. The wheel 27 is locked in position except and until the clock-work is completely unwound by a spring bolt 63, which can be retracted by the handle 58. This handle is locked by a catch 65, which engages an extension 67 of the handle 58 until an arm 68 extending from the arm 24 releases the catch 65. When the printing-frame is closed, the rotation of the shaft 14 operates to lower the arms 18, 19. The first action is to break the contact 39, 40, which cuts out the red lamp 42. The contact 39, 41 is then closed, and a pin 53 on the arm 18 presses a lever 45, which rocks the arm 52. The arm 52 then tilts the arm 49, and the spring 44, which is stronger than the spring 48, rocks the arm 43 and shaft 32. This brings a bridge 30 and the terminals 34, 35 down on to the periphery of the disk 25, and the contact bridge 30 closes the lamp circuit. The clock-work has been released by the release of the arm 24 from the arm 22, and a light arm 37 extending from the shaft 32 is rocked with the block 31 and starts the balancewheel 28. The roller 37 rests against the balance-wheel when in the upper position, and so prevents premature starting. When the clock-work has run down, a notch 29 in the periphery of the wheel 25 comes under the contact 30, which drops into the notch and breaks the lamp circuit. When the frame is opened, the arms 18, 19 rise, breaking the lamp-circuit contact 39, 41, and releasing the arm 45 from the pin 53. The spring 48 then returns the arm 43 and block 31, and the arm 49 is returned bv the spring 51 and holds the arm 43 raised. The handle 58 of the index-wheel 27 is fitted with an additional terminal 57, which can be adjusted to make contact with a terminal 56 on an arm 55, which extends from the shaft 32, and is raised and lowered with the movement of the block 31. This contact is made when the frame is closed and the terminals 56, 57 are in parallel with the terminals 34, 35, so that the lamp circuit is not broken when the clock-work runs down, but is maintained as long as the frame is kept closed.