Patent GB-115757-A (GB)
Title: Improvements in and relating to Selector Systems for Telegraphtypewriters.
Inventor: ALEXANDER ALBERT EDGAR
IPC: H04L25/49
Filed: 1917-08-30
Abstract: 115,757. Alexander, A. E., (Kleinschmidt Electric Co.). Aug. 30, 1917. Electric type-wheel actions; case-shift mechanism.-In a type-printing telegraph system of the kind in which the selection of a character on the typewheel or type-segment depends upon the duration of the current impulses, a positive impulse of predetermined duration selects a group of characters and a second positive impulse of pre - determined duration selects a character in the group. The change from one selection to the other is effected by interposing a negative impulse of one-half unit duration between the selecting positive impulses and the printing is effected by a negative impulse of one or more units duration When the characters are arranged in rows on a typesegment capable of rotary and longitudinal movement, the type-segment shaft is divided into two parts connected by a loose coupling in such a manner that a partial selection of a character may take place during the printing of the preceding character. When the characters are arranged in a single row on the periphery of a wheel the wheel is mounted upon a shaft subjected to a continuous turning movement and its rotation is controlled by an electromagnetic escapement the operation of which is controlled by the received impulses. In the arrangement shown in Fig. 1, pinions 20, 28 are driven at a constant speed by a motor 17<1> and are adapted to be engaged by toothed segments 21, 27 to impart rotary and longitudinal movements to a shaft carrying a type-segment 11. The segment 21 is pivotally mounted on the armature 22 of a magnet 23 and is connected to the typeshaft by links 24, 24<1>; and the segment 27 is pivotally mounted on the armature 29 of a magnet 30 and is connected to the type shaft by links 32. The segments 21, 27 are held in their operated positions by racks 21<1>, 27<1> adapted to be engaged by latches 26<2>, 34 respectively. The latches 26<2>, 34 are operated by magnets 26, 33 energized in series with the magnets 23 and 30 respectively, and each magnet is provided with holding coils 26<1>, 33<1>. The armature 22 and latch 26<2> control contacts 31, 31<1> in the circuits of the magnets 23, 30 respectively by means of which the selecting circuit is shifted from the magnet 23 to the magnet 30. The type-shaft is divided into two parts 13, 14, the lower part 13 of which is provided with a socket 13<1> carrying a pin 13<2>. The upper part 14 carries a pin 14<1> which is pressed against the pin 13<2> by a spring 15, while the joint is so arranged that the type segment 11 may be given a slight forward movement by a hammer 40 to force it against the platen 10. The hammer 40 is provided with a toothed segment 41 adapted to engage the toothed segment 11<1> of the typesegment 11 when the printing magnet 36 is energized in series with the letter-spacing magnet 49. The plunger 35<1> of the magnet 35 is provided with collars 44 adapted to open a normally closed switch 45 shunting the magnet armature 37<1> and the contact 42, and a switch 46 closed by the armature 48 of the magnet 35 to shunt the magnet armature 37<1> and the contact 38. The carriage-return magnet 50 is controlled by an arm 53 on the shaft 14 engaging a stop contact 52, and the line-feed magnet 54 is similarly controlled by the arm 53 and a stop contact 56. The selector magnets 23, 30 and the printing relay 37 are controlled by a polarized line relay 7 or a single current relay. Normally a negative current is on the line 1 so that the printing magnet 35 is energized through the operation of the relays 7 and 37. The type-segment, however, is not thrown against the platen 10 since the typeshaft in its normal position causes the arm 53 to abut against a stop 57. In the modified receiver shown in Figs. 2 and 3, the characters are arranged in a single row on a wheel 58 adapted to slide along a shaft 60 subjected to a continuous turning-moment and its rotation is controlled by an escapement 61 engaging a ratchetwheel 62. The moment tending to rotate the shaft 60 is supplied by a constantly rotating pinion 63 engaging a recessed toothed wheel 64 mounted loosely on the shaft 65. The recess in the wheel 64 contains a spring 66 one end of which is attached to the shaft 65 while the other end bears against the periphery of the recess. The shaft 65 drives the shaft 60 through a fast spur-wheel 67, a loose spur-wheel 68 and a spring 69 attached to the shaft 60 and to the wheel 68. The ratchet-wheel 62 is provided with a set of coarse teeth 70 and eight sets of fine teeth 71 each set containing five teeth. The wheel 62 is splined on the shaft 60 and its position thereon is controlled by a spring 76 and a cam 72 mounted on the shaft 65. The wheel 62 is also provided with zero position teeth 87 and in its normal position on the shaft 60 the escapement 61 engages one of the teeth 70. The escapement 61 is operated by a magnet 78 the circuit of which is controlled by a vibrator 77 released by a magnet 80 which is energized when the line relay 7 receives a pcsitive impulse. The rotation of the shaft 65 is controlled by a slow acting magnet 73 and a quick acting magnet 74 the former of which is arranged to withdraw a stop 73" out of the path of a notched disk 83 while the latter is arranged to withdraw a stop 74<1> out of the path of an arm 75 mounted on the shaft 65. The shaft 65 carries a printing-cam 84.