Patent GB-480300-A (GB)
Title: Improvements relating to apparatus for storing maps and like display articles of roll form
IPC: A47B63/06
Filed: 1937-07-12
Abstract: 480,300. Displaying. McCAULEY, M. D. July 12, 1937, No. 19265. [Class 3 (i)] Maps &c. are stored and displayed in apparatus comprising a casing 3 in which are two parallel shafts 15, 16 each carrying at each end a sprocket wheel 17, 18 over which run two parallel chains 19. The maps &c. 22 are wound on drums 21 which are rotatably supported in certain links 20 of the chains 19. The casing has a front opening 9 in which hangs a desk-top 10 which can be turned up into a sloping position to receive an unrolled portion of the map. The lower part of the opening 9 is filled by a door 14 which opens downwardly to give access. to the roller on which is wound the map to be displayed. The shaft 15 is driven to advance the map assembly by a motor which is of the two-way type controlled by an external knob 29, the direction of rotation of which switches the motor into rotation in the same direction. An indicator drum driven from the shaft 15 displays at a window the number of the map in position for display. A cam head 47 on a lever 46 is rocked by an axial projection on the drums 21 to restore the switch to its original position when the knob 29 is released. The drum so located is driven to unroll and to roll up the map by a friction wheel geared to a separate hanging motor which is swung by an external pedal to bring the wheel against a friction disc on the drum end. A clutch between the pedal and the hanging motor is put into engagement by a handle which switches in the said motor, and disengagement of the friction drive is effected by gravity. The friction wheel can also be manually adjusted along a radius of the drum disc to vary the speed ratio. Above the map assembly is a roller 82 also driven by a motor through friction gearing, with similar speed ratio adjustment. This motor is operated by the same switch and controls the motor driving the drums 21, these being energized non-simultaneously. A switch is provided, opposite one end of the drum 21 which is in position for unrolling, to stop the motor unwinding the map beyond a certain limit, the switch being pressed by a screwed rod meshing with a nut on the drum 21 and held against rotation by a fixed pin riding in a longitudinal slot in the rod. To the roller 82 are attached a plurality of straps to the ends of which is connected an elongated hook member engaging a similar hook member on the free map edge. On switching in the motor driving the roller 82, the map is unwound from its drum and passing over a roller 12 through the position shown in dotted lines at A, the door 14 having previously been opened, is wound on to the roller 82. The map may be very lengthy and the speed of transfer may be increased by means of the speed ratio adjustment till the required portion comes into view, when the motor is stopped. The desk B may then be raised, the roller 12 at its end bellying out the map. A roll 126 is then allowed to fall to retain the map on the desk B, this being effected by the weight of the roll or by securing means. The roller 82 is connected to its shaft by a spiral spring which is stressed when the desk B is raised, and tautens the map when the desk is lowered. Friction means is provided for retarding reverse movement of non-operating winding mechanisms.