Patent GB-660116-A (GB)
Title: Teleprinter receiving instrument
IPC: H04L17/26
Filed: 1947-12-30
Abstract: 660,116. Printing -- telegraph receivers. STAATSBEDRIJF DER POSTERIJEN, TELEGRAFIE EN TELEFONIE. Dec. 30, 1947 [April 16, 1943], No. 34839/47. Class 40 (iii). In a printing-telegraph receiver responsive to an equal unit code with start and stop signal elements and including a positioning shaft to which is given successively halved rotations in response to corresponding successive signal elements of one kind, e.g. marking, by the provision of discs having progressively doubled numbers of teeth, a receiving shaft started into rotation by the start element and arrested by the stop element carries a number of cams permitting the sequential operation of a number of coupling levers to move into position to engage a tooth on the associated disc on the positioning shaft, and a set of finger discs, equal in number to that of the selecting elements and rotated by impulses of the one kind, operates the coupling levers to release the positioning shaft to rotate until it is arrested by the coupling lever operated to the position to engage a tooth on the associated disc by the cam appropriate to the signal element received. On the occurrence of the start element-a break in the line current-the armature 3 aided by a spring 4 releases and allows a stop member 8 to rotate and remove a projection 10 from engagement with a projection on a disc 11 so that a receiver shaft 12 is allowed to rotate. A cam 13 on the shaft 12 engages a projection 14 on the lever 8 so that its top portion is moved to the left to free the armature 3 for response to the code elements of a signal. A cam 15 on the shaft 12 has five projections followed by recesses and by means of a lever 18 raises the armature 3 towards the receiving magnet at about the middle of each elementary signal period. If the element is spacing, the armature drops so that a notch between projecting positions 20, 21 latches the upper end of the lever 18. If the received element is marking, i.e. the armature attracted, the lever 18 moves to the right and the engagement of its projection 17 with the recess following the tooth allows a projection 22 to move clear of a tooth on a disc 23 carried by a control shaft 24. This shaft carries a number of cam discs 25, 32, 37 ... controlling locking levers 26, 33, 40 ... with which are associated timing cams, such as 34, 38, 43 on the receiver shaft 12. The raised portion of the cam 34, for example, holds the lever 33 out of operative position with respect to the cam 32 until approximately the middle of the first signal element. A positioning shaft 30 carrying a type-wheel, or other member determining the character to be printed, has a number of toothed discs 29, 35, 39, 42, 45, 46 controlled by the locking levers 26, 33, 40 ... the disc 29 having a single tooth which, in the start position of the type-wheel shaft 30, is engaged by the projection 28 on the locking, lever 26. The second disc 35 has a tooth disposed at 180 degrees to the latching end of the lever 33, and the third disc has two teeth disposed at 90 degrees relative to the end of the lever 40. The remaining discs have respectively four, eight and sixteen teeth equally spaced around their circumferences. If the first code element is marking, the cam disc 25 is rotated through one step and the lever 26 is rocked so that the shaft 30 is rotated through 180 degrees until the tooth on the disc 35 comes into engagement with the end of locking lever 33. If the second signal element is also marking, the cam 32 rocks the locking member 33 which frees the shaft 30 to rotate through 90 degrees until a tooth on the disc 39 engages the end of the locking lever 40. The printing operation takes place soon after the fifth signal element has been received and the cams 34, 38, 43 actuate the stop levers 33, 40, 44 so that the shaft 30 is released to move to its normal start position. An additional locking lever 47 is allowed to move under the action of a cam 49 so that it can limit the movement of the toothed disc 45 independently of the movement of the locking lever controlled by the cam on the shaft 24. The additional locking lever 47 is removed from its engaging position with the teeth of disc 45 before the next signal element is sensed. Printing operation.-During the rotation of the receiver shaft 12, a snail cam 50 operates a lever 51 to tension a spring 52 connected to one end of a rod 53 of which the opposite end is latched by a pivoted lever 55. Normally at the instant for printing, a projection of the lever 55 drops into a notch in a cam 57, also on the shaft 12, so that the lever 53 is suddenly released and actuates a hammer member 101 which brings the tape and inking ribbon into contact with the type-wheel 100. In the case of a signal which does not require printing, e.g. figures shift, the end 59 of the lever 55 engages a projection on a disc 58 carried on the positioning shaft 30 so that the lever 55 cannot move rearwardly to release the lever 53 actuating the printing hammer. The lever 53 is restored to its normal position after printing by a spring- biassed lever 103 associated with a cam 61 and carrying a stud engaging an inclined extension on the lever 53 so that rearward movement of the lever 103 rotates the lever 53 to the position in which it is latched by the member 55. Two adjacent discs 58 are provided as the type-wheel has two positions on the shaft 30 corresponding to upper and lower case characters. Case-shift.-A pivoted lever 67, Fig. 5b, has a projection which engages a notch in a cam 65 on the shaft 12 at approximately the printing instant, and if a disc 71 on the positioning shaft 30 has been positioned in accordance with a case-shift signal, the lower end of the lever 67 moves into a recess disengaging a projection on the lever from a tooth on a disc 74 carried by a shaft 72 which rotates through 180 degrees until arrested by a tooth on a second cam disc engaging with a projection on a lever similar to the lever 67 and operating in conjunction with a cam and recessed disc similar to the members 65, 71. The shaft 72 carries a cam engaging a pivoted lever which rocks a link so that a sleeve carrying the type-wheel is moved axially along the shaft 30. The Specification as open to inspection under Sect. 91 includes a modified arrangement, Figs. 7, 8 (not shown), in which the received signals are applied through a timing and signal regenerating arrangement operating generally in the manner described in Specification 34836/47 (as open to inspection under Sect. 91), and the marking signals are arranged to pass through the operating coils of respective motor units whihc provide rotation through 90, 45, 22¢ ... degrees. Spacing signal elements pass through other respective coils of the motors so that they are held against rotation. The motors include discs with progressively doubled numbers of poles, the spacing coils being opposite a pole, whilst the marking coils are always located opposite a space between two poles. A re-setting motor operated by the start element of the code brings the typewheel shaft to a normal start position. The arrangements of the operating coils and the construction of the motors are described in connection with Fig. 9 (not shown). This subject-matter does not appear in the Specification as accepted.