US 4,408,915 AGranted

Reverse tab control system for typewriters

AssigneeSCM Corporation

InventorMichael H. Smith

Life of this patent

Estimating the term…

Loading patent…

Abstract

A typewriter has a Keyboard (12), including a Tab Set Key (22), a Tab Clear Key (24), and a Tab Actuating Key (26). Operation of the tab set key stores stop positions of the Carrier (18) with respect to the typewriter's Platen (14). Shallow depression of the tab actuating key causes the carrier to move forward (right) to the next tab stop position. A first deep depression of the tab actuating key establishes a Reverse Tab Mode causing the carrier to move backward (left) to the nearest preceding tab stop position and causing the platen to rotate (index) so as to position the Printing Element (16) one line down on the paper, thereby to facilitate typing the next line of single column material without effecting a carrier return and forward movement of the carrier to the beginning of the column. Each subsequent shallow depression of the tab actuating key causes the carrier to move backward to the next preceding tab stop position without indexing, thereby to facilitate typing the next line of multiple column material without effecting a carrier return and forward movements of the carrier. The Reverse Tab Mode can be ended by activating almost any other key, whereupon subsequent shallow depression of the tab key causes the carrier to move forward in normal fashion.

Claims7

Dependent claims

A tab control system for a typewriter comprising a keyboard containing character keys;

type elements and a carrier therefor;
mechanical striking means attached to said carrier and capable of striking said type elements against a platen in accordance with characters selected on said keyboard;
said carrier, said mechanical striking means, and said type elements being arranged to move axially with respect to said platen, said carrier also being arranged to move a predetermined distance in a predetermined direction with the striking of any character of said type element means against said platen, said keyboard having:
(a) tab set means for manually presetting a plurality of tab stop positions of said carrier with respect to said platen,
(b) tab clear means for manually clearing any of said plurality of said tab stop positions, when set,
(c) tab actuating means responsive to a first kind of manual actuation thereof for moving said carrier to any of said plurality of preset tab stop positions,
said system including tab control means for moving said carrier from its present position to the closest preset tab stop position in said predetermined direction upon each manual actuation of said tab actuating means, said tab control means also being arranged to move said carrier to the closest predetermined tab position in a direction opposite to said predetermined direction and for rotating said platen through a predetermined angle so as to cause any type-receiving medium positioned around said platen to move to a lower line position with respect to said carrier, upon a second kind of manual actuation of said tab actuating means, and for moving said carrier to the closest predetermined tab position in said opposite direction and without rotating said platen, upon each manual actuation of said tab actuating means directly after said second kind of manual actuation thereof.

4 more elements

Dependencies are inferred from the claim text.