GB977493A - Improved type wheel printer - Google Patents

Abstract

977,493. Type-wheel printers. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 2, 1963 [Dec. 20, 1962], No. 48177/62. Heading B6F. A type-wheel printer comprises at least one annular type-carrier 52 mounted on a rotating drum 51 so as to be urged to rotate with the drum, and interposer means 58 operable to hold the type carrier stationary, the drum 51 being driven at a constant low speed during sensing of Y, X, O zone positions on a punched record card and at a higher constant speed during sensing of the 1 to 9 positions on the card, and the interposer being operated to hold the type carrier stationary if an Y, X, O hole is sensed, then released at the end of the sensing of the zone positions to rotate with the drum 51 at its higher speed, and again held stationary by the interposer if a hole in a numeric position is sensed. As described, a number of side-byside type carriers are mounted on the drum. The carriers 52 if not held by the interposer 58 are caused to rotate with the drum 51 by spring-pressed balls 55. Initially the drum rotates at a low constant speed with the type carriers held stationary by their interposers 58 engaging ratchet teeth 56. As the edge of the card reaches the reading station, a pulse is produced which releases the interposers so that the carriers rotate with the drum. If a hole in the zone position is sensed, an electromagnet 59 associated with the corresponding type carrier is energized so that its interposer 58 stops the corner rotation. Just after row O has been sensed, another pulse energizes all the electromagnets so that all the type carriers are held stationary in different relative angular positions depending on the Y, X, O sensing. This pulse also operates speed-change mechanism to accelerate the drum to a higher constant speed, four times that of the low speed. When row 1 of the card is sensed, another pulse is generated to release all the interposers so that all the type carriers now rotate with the drum at the high speed until 1 ... 9 holes are sensed in the corresponding card columns, whereupon the interposers are actuated according to the holes sensed to stop the carriers with selected type faces in printing position. When positions 9 of a card have been sensed, a pulse is produced which is applied to all the electromagnets, so that any carriers which have not previously been engaged by their interposers are now stopped, and the apparatus is ready to carry out a printing operation. After printing, a reset pulse is generated which releases all the carriers, the drum still rotating at high speed. The carriers rotate until they engage a mechanical stop which defines their initial position. In this position, a further pulse releases the mechanical stop but energizes all the electromegnets 59 so that the carriers are held stationary by their interposers. The same pulse operates the change speed mechanism so that the drum rotates at its low speed and the apparatus is ready to be set by the sensing of the next card. As shown in Fig. 1, the type faces 57 are situated on the outer edges of the ratchet teeth 56, which are engaged directly by the interposer pawl. In a modification, the type faces may be formed on one half of the carrier periphery and the pawl-engaging teeth on the other half.