Patent GB-190416871-A (GB)
Title: Receiving Telegraph Instrument.
Inventor: UNDERHILL CHARLES REGINALD
Filed: 1904-08-02
Granted: 1904-11-10
Abstract: 16,871. Underhill, C. R. Aug. 2. Telegraphs.-Relates to printing-telegraph receiving-instruments in which the type-wheel is positioned by means of mechanism controlled by the ordinary Morse combinations of " dot " and " dash " signalling-currents transmitted through the line-wire. An electric motor 2, Fig. 1, is coupled at 4 to a shaft which drives a shaft 11 through toothed gearing. To the shaft 11 is secured a coupling-member 10 adapted to be engaged by either of the coupling-members 8, 9. The frame 133 in which the members 8, 9 are journalled is adapted to be reciprocated by means of an arm 41 extending from the spring-controlled armature 7 of the electromagnet 5 which receives the line currents. The member 9 is consequently rotated while a line current is passing, and the member 8 is rotated during the intervals between the currents. Both these periods may have various values. The members 8, 9 bear spring- controlled switch arms 134, 135, Fig. 26, which are moved on to one or other of a series of contact-blocks according to the degree of rotation imparted to the members 8, 9 at each current intermission or impulse. The switch arm 135 is controlled by the line currents and the arm 134 by the intervals between them. In Fig. 26, the line or line-relay terminals are denoted by 145, 146. The electric motor 2 not only drives the shaft 11 but also, through suitable gearing, drives a pinion 28, Fig. 4, coupled frictionally to the shaft 19. On this shaft are also frictionally supported the pinions 34, 35, engaging with pinions 21, 22 on a shaft 20, the pinion 21 being keyed to the shaft, and the pinion 22 capable both of sliding and of rotating upon it. These two pinions are alternatively engaged by the extremities of an escapement device 42 mounted on the vertical shaft 40 which carries the armature of the electromagnet 5. The pinions 21, 22 are thus driven alternately, the pinion 21 being driven during current impulses, and the pinion 22 during intermissions, but both through friction gearing. The axial movements of the pinion 22 and the segment 45 which it carries are effected by the action of an electromagnet 66 and pawl 65 on a rack on the sleeve 57, which is itself incapable of rotation. The coupling-box 61 allows rotation of the pinion 22 relatively to the sleeve 57. A detent pawl 73 under the control of an electromagnet 74 prevents the return or leftward movement of the pinion 22 and segment 45 through the action of the compression-spring 71. Projecting inward from the segment 45, Figs. 6 and 7, are five pairs of studs 45, 47, 48, 49 and one single stud 56. The studs 47, 49, &c. are longer than the studs 46, 48, &c. The positions of the studs circumferentially represent the various rotational values of a '' dot " and a " dash " in the various positions they may occupy in the Morse character. Thus the studs 46, 47 represent 1 and 16 units of rotation respectively, these being the values allotted to a dot and a dash occupying the first place in the character. The studs 48, 49 represent 2 and 12 units of rotation respectively, the values allotted to the dot and dash in the second place in the character. By thus allotting different rotation values to the dot and dash in different places in the character, different summation values are produced for all the Morse characters. Secured to the shaft 20 is a stop-arm 77 adapted to co-operate with the long or " dash " studs. The longer arm 76 which co-operates with the " dot " studs is carried by a sleeve 79 which can be coupled to the shaft 20 by means of a sliding clutch member 80. The shaft 20 is normally coupled at 95 to the typewheel 92, but the latter can be released from the shaft by the agency of the electromagnet 102. The sleeve 79 cannot move axially on the shaft 20. but is capable of a rotary movement of about 180‹ relatively thereto. The sleeve 79 is normally coupled to the shaft 20 but is released from it when the electromagnet 91 is energized. Assuming now that transmission is taking place over the linewire, and that the first signal-component of the first Morse character is a dot, the member 9 will be engaged with the member 10 for a short period, and the switch arm 135 will not be moved sufficiently to bring it off the insulating-block 147 on to the first contact-block 148. The magnet 91 consequently remains de-energized. The escapement 42 frees the wheel 21 and locks the wheel 22. The shaft 20 and type-wheel 92 consequently move through one unit space, the stop-arm 76 then coming in contact with the stud 46 and arresting the movement. If the first signal component had been a dash, the switch arm 135 would have moved on to the contact-block 148 and the electromagnet 91 would have caused the sleeve 79 to be declutched, the type-wheel would then have rotated through 16 units, i.e., until the stop-arm 77 reached the stud 47. The arm 76 would have been left behind against the stud 46. The short currentintermission which follows the initial impulse causes a short engagement between the members 8, 10, and the switch arm 134 moves on to the contact-block 152, the other switch arm being restored to the normal position by its spring. The electromagnet 66 being thus energized, the wheel 22 and segment 45 are shifted axially one step, the second pair of studs being brought into the plane of the arms 76, 77. Before this happens, however, the wheel 22 (now disengaged from the escapement 42) follows up the preceding movement of the arm 76 (or 77, in the case of a dash), the stop 78 again abutting against the arm 76, and the latter against the arm 77 in readiness for the next movement of the shaft and type-wheel. The second signal-component is now received, and, assuming this to be a dash, the arm 77 moves on 12 units to the stud 49, making a total rotation of 13 units on the type-wheel, which thus integrates the rotation values of the signal-components. Special provision is made for dealing with the letter " L " and the numeral " 0," which in the American Morse code are represented by " dashes " of more than the standard length. These two types are carried on a special printing-lever, and one or other of them is brought to the printing point according as the switch arm 135 is carried on to the contact-block 149 or 150. If a continuous line current is received, the arm 135 is carried on far enough to disconnect the switch arm 160 from the contact 161. thus brealiing the circuit of the motor 2, the field-magnet coils of which are shown at 168. Before the switch is operated, the contact at 151 practically short-circuits the motor armature through the resistances 169, 175, thus slowing it down. Printing is effected by means of an electromagnet 119, the circuit of which is closed when a current-intermission is of sufficient duration to allow the switch arm 134 to reach the contactblock 154. Ordinary letter-spacing is effected by the platen on its return movement after the impression. The double space after a word is produced by an electromagnet 131, the circuit of which is closed when a still larger current-intermission than that already referred to is received. The contact-block 153 is provided to allow of the extra spaces which in the American Morse code occur in some cases within the code characters. The releasing-electromagnets 102, 74, 110 for zeroizing the type-wheel, releasing the sleeve 57, and releasing the special printing-lever after use are placed in parallel in a circuit which includes a make-or-break wheel 180 on the shaft of the paper feed-roll. The releasing-electromagnets are thus energized after every impression. If the line current ceases altogether, the switch arm 134 is carried on to the contact-block 156, practically short-circuiting the motor armature as already described and finally opening the switch 160, which, as shown in Fig. 1, stands in the same relation to both switch arms 134, 135. A centrifugal governor on the motor shaft makes or breaks a switch contact 170 and controls the speed by alternately cutting out and re-inserting the resistance 169.