Patent GB-190212458-A (GB)
Title: Improvements relating to Telegraphic Perforators.
Inventor: JUDD WALTER
Filed: 1902-05-31
Granted: 1903-05-28
Abstract: 12,458. Judd, W., Fraser, A., and Draper, G. May 31. Telegraphs.-Relates to perforators employed to punch the paper strip used in automatic telegraph transmitters, and is described with reference to perforators in which dots and dashes are represented by holes on opposite sides of the central perforations. The punches are actuated by electromagnets a controlled through relays d, so that a gentle touch on the keys c is sufficient to effect perforation. On depressing, say, the left-hand key c, the current from the positive pole of the battery b passes through the coil g of the lower relay d, and returns to the negative pole through the wire g<1>, contacts i, j, and wire g<2>. The relay being energized, contact is made at e, f, and the current from the positive pole passes through the contacts z, f, e to the armature of the relay. The current divides at this point, one branch comprising the coil h, contacts i, j, and conductor g<2>, and the other comprising the punch magnet a, conductor a<1>, and contacts k at the other punch magnet. The coil h being thus energized, the circuit of the punch magnet remains closed even when the key c is released, and it is not until the stroke of the punch magnet is completed that the relay d is de-energized by the breaking of the contact at j, i. As the circuit of each punch magnet includes the contacts k at the other, the movements of one must be fully completed before the other can be operated. A device is provided for automatically causing a spacing action to take place during the pauses between the letters of a word, thus supplementing the feed which always follows the punching of a letter element. This device comprises the magnet o and spacing-magnet n. Associated with each punch magnet are a pair of contacts p, q, which are shown in the diagram, for convenience sake, in the neighbourhood of the contacts j, i, but are in practice near the contacts k. When the armature of the punch magnet is fully depressed, the contact p, q is closed. Current then passes from the positive pole of the battery b through the conductor b<1>, coil of magnet o, contacts q, p, and conductor b<2> back to the battery. Both armatures of the magnet o are attracted, and owing to the sluggish nature of the magnet they remain attracted until a pause occurs between letters. The sluggishness is produced by the use of hard iron cores and shunted coils. During the pause both armatures are released, but the left-hand one is constructed to act more quickly than the other, and for a moment the contacts r, s are bridged by the conductor o<1>. Current then flows through the circuit comprising the conductor b<1>, contacts r, s, spacing-magnet n, and conductor b<2>, and the required feed is produced. For spacing words and sentences, the spacing-key t is used. It closes two pairs of contacts u, v, of which v directly closes the circuit of the space magnet n, and u closes the circuit of the magnet o. An automatic spacing action thus follows after the direct action, and a double feed results. To ensure that enough time for the automatic spacing action shall be allowed by the operator, the feed-roller shaft w is provided with a cam x of ratchet form, which breaks contact at z while the feed is actually taking place, and prevents premature operation of the punch magnet. A high-resistance electric bell 2 rings if an attempt is made to operate the punch magnet while the contact is broken at z. Fig. 4 shows the rod punches 3, which are clamped in the bars 5 by screws 4. A thin plate 9, Fig. 6, punched with holes to correspond with holes in the guide-plates 7 and 8, rests on the plate 7 and takes the wear. This plate can be reversed when one set of holes is worn, and can be discarded when useless.