Patent GB-207257-A (GB)
Title: Improvements in or relating to coding or de-coding machines
IPC: G09C3/00
Filed: 1922-08-22
Abstract: 207,257. Hole, S. Aug. 22, 1922. Machines for coding and decoding.-Relates to coding and decoding machines of the kind in which one set of keys is connected to a second set of keys through a code-changing device comprising two relatively movable members having aligned transmission points for each key. The invention comprises two sets of keys both operatively connected to its own mechanism for writing, a single connection between each key and the code-changing device, self-operating means for each key, means for controlling the self-operation of one set from the other set, and change-over mechanism adapted to connect either set of keys so that it can be manually operated to control the self-operation of the other set, its own self-operating means being rendered inoperative. The controlling means is in the form of a key-operated switch mechanism for connecting the source of power through the code-changing mechanism, and the change-over mechanism comprises a hand-operated switch. In a pneumatic arrangement, the keys A', B<1> of two standard typewriters A, B are connected together through a code-changing device E, E<1> bv pneumatic transmission tubes G<1>, G<2>, G<3>, N, F, F<1> connected with an exhaust chamber G. The disc E of the code-changing device is fixed and provided with a circular series of ports E<3> engaged by nipples E<4> connected to the tubes F. The movable disc E<1> is provided with a circular series of tapered holes E<5> engaged by hollow tapered plugs F<2> connected to the tubes F<1>. Each plug F<2> is provided with a flat F' on which a sign is marked, so that by slipping the plugs out of their holes different key-settings can be readily made. The movable disc is provided with teeth E<6> and is stepped round by a pawl K<3> when the key K is depressed. In the normal position of the key the pawl K<3> abuts a stop K<4> and is clear of the teeth E<6>, the disc being held against movement by a retaining-pawl J. At the end of one revolution of the disc a stop J<6> thereon engages a pin J' on the retaining-pawl, and the disc is returned to its zero position under the action of a helical spring E<7>. Both code-changing members E, E<1> may be movable. The transmission tubes F, F' are threaded through holes in plates L marked with signs corresponding with the keys, so that any particular tube can be readily located. Pneumatic keyboard operators. - The valve chests C on each typewriter comprise cylinders C<2> containing pistons C' connected to the keylevers by links B<2>, a port C<5> in each piston being normally out of lines with a transverse passage C<3>. Each passage C<3> communicates with a longitudinal passage C<4> blocked at one end and connected to one of the transmission tubes N at the other end. A valve M closed at its upper end has a side port M<1>, and is raised or lowered by a hand-operated cam-slotted slide M<3> common to all the key-levers in one row. The port M' can be put into communication either with the passage M<2>, in which case the key-lever is lowered by atmospheric pressure, or it may be put into communication with the transverse passage C<3> so that when the key-lever is depressed manually the port C<5> is in line with the port M<1> and power is transmitted through the code-changing discs.