Patent GB-190505771-A (GB)
Title: Improvements in or relating to Printing Telegraphs
Inventor: BARCLAY JOHN CHARLES
Filed: 1905-03-18
Granted: 1906-03-01
Abstract: 5771. Barclay, J. C. March 18. Telegraphs.-Relates to printing- telegraph receiving- apparatus, and comprises the adaptation to known powerdriven printing- mechanism of electro - magnetic actuating-means in substitution for the keys, and also improved devices for selecting a printing-magnet by means of a sequence of long and short current impulses in the line. Fig. 6 shows in sectional elevation a powerdriven typewriter of the character described in Specification No. 335, A.D. 1903, [Abridgment Class Printing, Letterpress, &c.]. An electric motor drives the power shaft 1 continuously ; the shaft is provided with h a singlerevolution clutch which can be thrown into action by means of a" clutch " magnet " or " spac- "ing magnet" designated 9 in the diagram of the circuits and apparatus shown in Fig. 15. During the single revolution of the normally - disengaged clutch member, a cam 6 rocks forward a driving-bar 18, which carries with it any pawl 20 which may have been depressed by the energizing of one of the printing-magnets 24. The gear-sector 19 is thus drawn forward, and the corresponding segmental gear or tumbler 31 is first brought into operative engagement with the sleeve 28 (of which there is one on each side of the typewheel 3) and then turns the sleeve through an angle which differs for each tumbler. The sleeve carries a gear-sector 29 meshing with a pinion on the type-wheel shaft. The type-wheel rotates until the heel of the tumbler lifts a bar 35 and causes a pin 36 to engage the teeth of a stopping- ratchet 37 on the type-wheel shaft. Rotation of the type-wheel being thus prevented, further movement of the tumbler carries the type-wheel forward until it strikes the platen. The cam 6 is so shaped that the actual impact is due only to momentum. The type-wheel wipes past an inking-roller 39 on its way to the impression point. One feature of the invention consists in the provision of means for holding down each pawl 20 positively until the driver 18 engages with it, thus preventing the possible loss of some of the letters when the apparatus is working at high speeds. For this purpose, a spring bolt 20<a> is associated with each actuating-rod 22, and engages above the lug 22<a> which depresses the pawl 20 when the electro-magnet 24 is energized. The pawl consequently remains depressed until the driver 18 comes into contact with the plunger 20<b> and pushes back the bolt by means of a universal bar 20<c>. In an alternative form of locking-device, pivoted latches are employed. Letter-spacing is effected positively by means of a pawl which is normally out of engagement with the carriage feed-rack but is brought into engagement with it and then spaced forward one step by means of a cam carried by the normally stationary portion of the single-revolution clutch. For returning the carriage at the end of a line, the electro-magnet 49, Fig. 15, is energized. The armature of the electro-magnet serves to bring a friction wheel into engagement with another on the motor shaft, and thereby to drive a pinion engaging with the carriage feed-rack. Linespacing is effected by an electro-magnet 59, Figs. 6 and 15, the armature of which serves to rock a lever provided with an aperture through which passes loosely a bar carried by the paper carriage and connected with the platen feed-pawl. Linespacing can therefore be effected in any position of the carriage. The "sunflower" and selecting mechanism are shown diagrammatically in Fig. 15. The line-wire passes through a polarized relay 74, which is shown differentially wound to permit duplex or quadruplex operation. For each signal to be transmitted, six impulses are transmitted through the line, of which some may be short and others long. Tho impulses are alternately positive and negative, a local circuit being consequently closed alternately through circuits 76, 77 which include the sluggishly-acting neutral sepa- " rator relay 78, the opposing coils of an electromagnet 79 which controls the " sunflower," and the synchronizing-magnet 78. The six impulses consequently give six oscillations to the escapement 96, the escapement-wheel 95 being thereby advanced by three teeth and the ratchetwheel 93 by one tooth, during which time all the six contact-devices 87 ... 92 of the sunflower are operated in succession. The six impulses all pass through the relay 78, but it only responds to the long impulses, and consequently the battery 84 is only connected with such of the five contact-devices 87 ... 91 as are represented by long impulses among the first five impulses in the signal. The sixth contact-device 92 is permanently connected with the battery 112, the wire 113 thus receiving an impulse at the end of each signal. The five contacts 87 ... 91 are connected with the five selecting-relays 105 ... 109, the actuation of which in various combinations enables a circuit to be selected through any one of the printing-magnets 24, or through the carriagereturn magnet 49, paper-feed magnet 59, shift magnet 73, or shift release magnet 120. The closing of the sixth contact-device 92 completes a circuit from the battery 112 through the wire 113 and slowly-acting " restoring" relay 114 to ground, and also through the back contact of the relay 114, wire 115, and the contact-springs of the selecting- relays to the selected printing-magnet 24 and clutch or spacing magnet 9. It is a feature of the invention that the selecting-relays are controlled directly through the sunflower contacts and that the printing-magnet circuit is also closed directly through the sixth contact. The clutch or spacing magnet may be energized through the circuit 116 independently of the printing-magnets, and, as the independent operation of the spacing- magnet is necessarily of very frequent occurrence a signal consisting of six short impulses is used for this purpose. This signal does not affect the operation of any of the selecting- relays. The selecting-relays are restored to the normal condition by means of a restoring-circuit including a wire 118, restoring-windings on the selecting- relays, and the front contact of the restoring- relay 114. To prevent the transmission of a spacing-signal through the circuit 116 when the selecting-relay tongues fall back after the transmission of a character signal, a slowly acting "spacing cut-out" relay 117 is provided. This relay, which is in parallel with the restoring- relay 114, fails to break the spacing-circuit when the six short impulses are received, but breaks the circuit each time any of the other selecting- signals is transmitted, before the selecting-relays are restored to the normal condition. Sparking at the contact-points of the selecting-relays is prevented by the relay 114 being caused to break the circuit 113, 115 just before the restoring- circuit 118 is completed. When the shift magnet 73 is energized by its special selecting-signal, the circuit 116 of the spacing-signal is broken. When the usual spacing-signal is sent, the shift release magnet 120 alone is, therefore, energized, the spacing-signal thus serving for two distinct purposes. The carriage-return magnet 49, which is required to be used less frequently than any other, is selected by a signal consisting of six long impulses. In order that the magnet 49 may be maintained energized for a sufficient time, its armature is caused to break the restoring-circuit 118. The circuit of the magnet 49 consequently remains closed until, on the completion of the return movement of the carriage, it is broken mechanically.