GB639241A - An improved telegraphic printing system - Google Patents

Abstract

639,241. Type - printing telegraphy. GRETENER, E. Dec. 20, 1947, No. 33712. Convention date, May 2, 1946. [Class 40 (iii)] A type-printing receiver operating to an equal-length, equal-unit code comprises a typewheel rotating synchronously with a transmitter and having type-faces bearing elemental signs from which characters may be build-up and arranged for movement parallel to the axis of the type-wheel, the signs required to form a character being impressed in sequence in their correct position during one revolution of the type-wheel. Any character can be formed by selected ones of fourteen elemental signs, each character being represented by a fourteen-unit code in which no-current elements represent the signs to be printed and current elements represent the signs not required for the particular character. At the transmitter 10 a selected character cam 11 rotates and its notches 51 open transmitting contacts 13 at times characteristic of the signs required to compose the selected character. At the receiver 14 a shaft 48 driven synchronously with the transmitter bears a printing wheel 25 and an armature wheel 47 and drives a type-wheel 15. As each type-face 17 comes opposite the head 22 of a printing hammer 20 a corresponding notch 26 on the printing wheel 25 allows the printing hammer 20 to rotate about its pivot 21 under the action of a spring 49. If a current element is being received the armature 36 is attracted and latches a lever 29 thus preventing rotation of the printing hammer 20. If, however, a no-current element is being received the armature 36 releases, its projection 45 entering a notch 46 in the armature wheel, and allows the printing hammer 20 to strike the appropriate type 17. The inked type, which is loosely mounted in an oil-impregnated, sintered metal bearing, strikes a stationary tape 18 backed by a resilient roller 19 and rebounds sharply, aided by a return spring 81. During the last part of its forward traverse the type travels freely, the printing hammer 20 being arrested by a fixed stop 28, and printing can thus take place although the type-wheel 15 is rotating. The armature 36 and printing hammer 20 are restored to normal by the sloping faces of the notches 46 and 26 respectively and at the end of a revolution of the type-wheel 15 the tape 18 is stepped on ready for a following character.