Patent GB-1151808-A (GB)
Title: Pulse-Operated Line Printer for Electronic Data-Processing Installations.
Inventor: LANGENBERGER HELMUT
IPC: G06K15/06
Filed: 1967-06-09
Abstract: 1,151,808. Selective-printing machine. WALTHER-BUROMASCHINEN G.m.b.H. 9 June, 1967 [23 June, 1966 (2); 12 July, 1966], No. 26814/67. Heading B6F. A pulse-operated line printer comprises a number of type wheels 30c, Fig. 4, for simultaneously printing a line, each type-wheel being carried by a lever 22 which is moved to effect impression by a spring 23a and is returned to its inoperative position by a second spring 23b. The lever 22 is pivoted at 22e, and carries a pivoted lever 21. The spring 23a extends between the two levers and the spring 23b extends between the lever 21 and a fixed support. Normally, the spring 23a holds the lever 21 against a stop 22b on lever 22, and the spring 23b holds the lever 22 against a stop 22d. In this position, a catch 22c on the lever 22 is engaged with a trigger lever 33. During one revolution of a drive shaft 3, Fig. 1, each typewheel 30c is set as described below and simultaneously a member 20 spring-pivoted to a lever 19 is moved downwardly. The member 20 engages the end 21a of the lever 21 to move the lever 21 downwardly to stress the springs 23a, 23b, whilst the lever 22 is still held by the catch 22c. After setting has been effected, the trigger lever 33 is operated as described later to release the catch 22c whereupon the lever 22 is moved by the spring 23a to effect printing. During such movement, the lever end 21a is withdrawn from the member 20 and the spring 23b becomes operative to return the levers 21, 22 to their original positions. A member 18 oscillated about a shaft 13 by a crank 16 on the shaft 3 has a slot 18a engaging the lever 19 to oscillate the lever and therefore move the member 20 up and down. The pivot 19c of the lever 19 has an eccentric adjustment whereby the position of the member 20 relative to the lever end 21a can be adjusted to vary the instant at which the end 21a becomes free of the member and therefore to vary the impression impact. If a type-wheel is set to a " no print " position where it does not present a character, actuation of the trigger lever 33 is prevented as set out below so that the type-wheel is not moved towards the platen. Type selection.-The drive shaft 3 is clutched to a main shaft 1 so as to make one revolution for each line printing operation. A sector 14 with code perforations is oscillated about the shaft 13 by cams 5, 6 on the shaft 3 through links 10, 11. Another sector 24 with saw-teeth 24a and gear teeth 24b is freely mounted on the shaft 13, and is urged by a spring 23c to hold an inner edge thereof against a pin 15 on sector 14 so that the sector 24 tends to move clockwise with sector 14. A photo-electric cell 25 scans the perforations in the sector 14, and when the perforation corresponds to a character stored in a computer, an electromagnet 26 is briefly excited to release a pawl 28 which then engages one of the saw-teeth 24a. During the movement of the sector 24, the gear teeth 24b set the type-wheel 30c through intermediate gears 30a, 30b. As the sector 14 continues its clockwise movement, the pin 15 engages a lever 32 which actuates the trigger lever 33 so that an impression is effected. Alternate electromagnets 26 are staggered with respect to one another. Type-aligning. As a type-wheel-carrying lever 22 is moving to effect impression it allows a pawl 36 pivoted thereto at 36<SP>1</SP> to be moved by a spring 35 into engagement with teeth on the typewheel for alignment purposes. No-print position.-When the pawl 28 engages the first sawtooth 24a of segment 24, the corresponding type-wheel is set so that no print is obtainable therefrom. In this position of the segment 24, a cam 24d thereon engages an elbow 33c of the trigger lever 33 and prevents release of the corresponding type-wheel lever 22 for an impression movement. A modified arrangement is described (Fig. 3) for preventing release of the lever 22 when the no-print setting of the type-wheel occurs at the end of the type-setting movement of segment 24 instead of at the beginning.