Patent GB-248836-A (GB)
Title: Improvements in or relating to receivers for type-printing telegraphy
IPC: H04L15/34
Filed: 1924-12-10
Abstract: 248,836. Smith, R. S Dec. 10, 1924. Type - printing telegraphs. - Relates to a type-printing receiver for use with a code in which several characters are represented by different numbers of impulses of two or more kinds. The successive received impulses forming each character are distributed to electromagnets which release corresponding selector members, and these released members are collected on a support which is subsequently removed bv the action of a controlling magnet to allow them to coact with a carrier bearing combinations corresponding to the characters to bring the appropriate type into printing position. The application to a code employing dots and dashes with a maximum of six impulses per character is described in detail. Distribution of received impulses to selector magnets. The receipt of a dot or a dash energizes respectively relay magnets 9 or 10, Fig. 1, to move the armature 11 or 14 from a back contact 12 or 15 to a front contact 13 or 16, and the successive relayed impulses are delivered by a distributor drum D to the appropriate dot selector magnets S<1> - - S<6> and dash selector magnets L<1>- - L<6>, the magnets S<1>, L<1> corresponding to the first impulse for a character, magnets S<2>, L<2> to the second impulse, and so on. The drum D comprises six contact rings 2 - - 5, 7, 8, Fig. 2, represented diagrammatically as flat rings in Fig. 1, co-operating respectively with brushes 31 - - 36 carried bv an arm 1 rotatable through a clutch 25, 26 and reduction gearing of six to one from a phonic wheel making one revolution per signal element. The brushes 31, 32, and 35 are electrically connected to the brushes 33, 34, and 36 respectively. The rings 2, 3 are continuous and are connected to the back contacts 15, 12 respectively. The rings 4, 5 are each divided by insulating strips 6 into six equal segments, successive segments of the ring 4 being each connected to one end of the winding of the corresponding selector magnet S<1> - - S<6>, and successive segments of the ring 5 each to one end of the winding of the corresponding selector magnet L<1> - - L<6>. Each of the rings 7, 8 comprises six contact blocks separated by blocks of insulation. The other ends of the windings of the selector magnets are connected through a common lead 18 and magnet 19, 20 to the negative pole of the current source 21, and the circuit from the positive pole is completed through the contact 13 or 14, resistance 17, and back contact 15 to 12, ring 2 or 3, and brushes 31, 32 or 33, 34 to the ring 4 or 5. A condenser 22 and resistance 23 are arranged in shunt with the magnets 19, 20. On receipt of the first impulse of a character the magnets 19, 20 and one or other of the magnets S<1>, L<1> are energized. The magnet 19 moves a comb 54 against the pull of a spring to bring its teeth into position to support one of the pivoted selector members 51, Figs. 2 and 5, which falls owing to the removal of its support) 53 constituting the armature of the energized magnet S<1> or L'. The magnet 20 operates a lever 20a to engage the clutch 25, 26 to rotate the arm 1. As the arm 1 passes over the strips 6 between successive segments 4, 5 the magnets 19, 20 are maintained energized by the condenser 22. The second impulse of a character thus energizes one or other of the magnets S', L<2> and similarly for the succeeding impulses until a selection of the members 51 corresponding to the character is supported on the teeth of the comb 54. Type selection and printing. Following the receipt of the last impulse of a character the armatures 11, 14 engage their back contacts 12, 15 and the magnets 19, 20 are de-energized. The comb 54 is thereupon moved by its spring to allow the free ends of the selected members 51 to engage the surface of a cylinder 52, and the clutch 25, 26 is disengaged to allow the arm 1 to be returned to its initial position by a spring 45. The cylinder 52, as shown developed in Fig. 8, is formed with conducting edges 46, 47 separated by insulating strips 48, 49 extending axially and circumferentially respectively, the strips 49 between successive strips 48 being arranged as shown to correspond with the code designations of the several characters. These code designations are arranged in six zones, characters designated by one impulse being represented in the first zone, those designated bv two impulses in the second zone, and so on, and successive zones are separated by insulating strips 50. The cylinder 52 carries the type wheel 64 and is driven through a friction clutch 58, Fig. 2, when a pawl 66 is disengaged from one of a series of six projections 61 on a toothed wheel 60 carried by the cylinder, these projections being disposed opposite to the strips 50. This displacement is effected by the energizing of a magnet 68 when the brushes 35, 36 connect the contact blocks of the rings 7, 8, the circuit including a contact 73 closed by the lever 20<a>. As the cylinder 52 rotates a position is reached in which the selected members 51 bridge the strips 49 corresponding to the selected character, and a circuit is then completed between brushes 77, 78 bearing on the conducting edges 46, 47, this circuit including a condenser 79, a magnet 75 operating the printing hammer and, if desired, a magnet 76 operating a pawl 81 for engaging the wheel 60 to hold the type wheel during printing. Alternatively a locking pawl may be carried by the hammer 74. The pawl 66 is also movable axially to disengage the projections 61 by a spring 69 but is held against the action of this spring by a magnet 70 energized by the closure of a contact 71 by the armature of the magnet 19. When, therefore, the magnets 19, 70 are de-energized, the pawl 66 moves axially, the cylinder 52 completes its revolution, and a cam 62 then returns to the pawl axially. The actuation of the printing hammer 74 closes at 82 a contact enabling the condenser 79 to discharge through one or more magnets 83 adapted to lift a frame to restore the selector levers 51. The paper feed is effected by a magnet in a circuit closed by the arm 1 in its initial position. The arm 1 also closes, on completing a revolution, contacts short-circuiting the magnet 20 to disengage the clutch 25, 26.