ES344148A1 - Printing apparatus with no-print feature - Google Patents

Abstract

Typewriters using spherical print head.-In a variable spacing machine and which may print justified lines, the drive to effect print-head impression movements may be disabled in a manner such that character selections can still be registered, as in typing a trial line, but the selected characters are not printed. As described, the machine employs a type-head 1 which is rotated and tilted to select a required character by manually operated keys or by electromagnetic devices, and is mounted on a carriage 3 moved by a lead screw 18 for letter spacing in amounts corresponding to the character sizes as described in Specification 1,053,186. Impact of the type head with the ink-ribbon is effected by the engagement of a cyclically rotated cam 60 with a follower roller 62. The cam 62 may be axially shifted to arrange for three degrees of impact, or no impact, in accordance with what key is operated. The cam 60 comprises three axially spaced parts 60a, 60b, 60c, Fig. 4, and the roller 62 is moved axially to be engaged by one of these parts according to whether a character e.g. W requiring a high velocity impact, a character, e.g. B requiring a medium velocity impact or a character, e.g. "," requiring a low velocity impact, is to be printed. A further cam part 60d is provided, and if the roller 62 is positioned opposite this part no printing movement of the head 1 takes place. The roller 62 is moved by a band 80 passing around a fixed pulley 81 and a pulley 79 carried by a lever 78 and it is by movement of the lever 78 that positioning of the roller 62 is effected. The lever 78 being appropriately operated by a linkage to a follower member 51 and stops 55, 56, 57 controlled by what character is to be printed. Depression of a character key operates an interposer such as 20, 21, or 22, which actuates a bail 25 causing a clutch 46 to turn a filter shaft 27 through 180 degrees. The shaft 27 drives the interposer forwardly so that coded projections thereon engage bails to effect the selective movement of the type-head 1. At the same time, a cam 50, Fig. 5, or shaft 27 is also rotated through 180 degrees. The follower member 51 with a follower roller 52 is operated by the cam 50 and its movement is determined by stops 55, 56, 57. The member 51 is connected to the pulley-carrying lever 78 by a linkage 72 . . . 76. If the character-key W is depressed, the stops 55 . . . 57 remain in the position shown, so that movement of the follower is limited by the stop 55. When this occurs, no movement of lever 78 and pulley 79 takes place so that roller 62 remains in its normal position opposite the high velocity part 60a of cam 60 so that a high velocity impact is obtained. When, however, the character-key B is depressed, a tab 21a on its interposer 21 engages a vane 96 on a bail 97 and rotates the bail, or that, through connections 98, 100, 101, the stop 55 is moved out of the way of the follower 51 which now engages stop 56. In this position lever 78 is rotated to move pulley 79 to the right so that roller 62 is positioned opposite cam surface 60b and a medium velocity impact is obtained. On depression of character-key "," its interposer 20 is moved into contact with a vane 105 on a bail 106. Movement of the bail 106 pulls a link 108 attached to the stop 56 to move the stop to an inoperation position. An extension 56a on the stop 56 engages stop 55, to move the latter to inoperative position. The throw of follower 51 is now determined by stop 57, and is such that pulley 79 is moved to the right a distance such that roller 62 is situated opposite cam part 60c and a low velocity impact is effected. Suppression of printing movement of type head is effected when the space-bar 14 is operated. The interposer 33 of the space-bar has a projection 33a which engages a vane 120 on a bail 121 and rotates the latter. A crank 122 is attached to the bail 121 and is connected by a link 125 to an extension 57b of the low velocity stop 57. Rotation of the bail 121 moves the stop 57 to an inoperative position, and simultaneously the stops 55, 56 are moved to inoperative position by projections 56a, 57a on the stops 56, 57. The throw of follower 51 is thus increased, and the consequent movement of lever 78 and pulley 79 is such that the roller 62 is positioned opposite the "no-print" cam part 60d so that no impression movement of the type-head 1 takes place. A "no-print" key 15 is provided, and when depressed operates through a lever 140 on a second arm 123 attached to crank 122 so that, as in the case of "space-bar" actuation, no impression movement of the type head 1 takes place. The key 15 can be latched in depressed position (Fig. 8) for repeated "no-print" operations. This is so that a trial line may be entered into the keyboard and the proportional spacing mechanism without actual printing. Variable spacing by actuation of the space-bar multiple action keys.-As in most electrical typewriters, the space-bar 14 can be depressed a certain distance for a single spacing operation or can be depressed further for a repeat spacing operation. The actual number of spacing increments is controlled by a dial. Variable escapement mechanism back spacing. As described in Specification 1,053,186 means are provided wherein links 66, 77, 86 actuate members in a block 41 to set pins 35 in a wheel 36 so as to control the escapement mechanism and effect spacing according to the character sizes. The pins 35 also act as a memory to control back and forward space movement of the carriage 3 to ensure accurate corrections.