Abstract: A thesaurus feature for finding synonyms of words is provided for use with electronic typewriters having electronic spelling dictionaries for storing words in a data base contained in an electronic memory. Each word in the electronic dictionary which appears in the thesaurus is identified by a special code immediately following the word, so that the dictionary can be scanned quickly to determine if a given input word is in the thesaurus. If the word is in the thesaurus, the search for synonyms can proceed quickly. The input operations required of the typist are patterned after previously known operations to eliminate extensive learning or relearning on the part of the typist. Cascaded scanning of the display and listing operations are utilized to conserve time.

Abstract: A word-processing system or memory typewriter has the usual keyboard, input display and printer, including a correction ribbon for removing erroneous characters from a document held in the printer; together with a spelling dictionary stored within the memory, an error indicator activated upon entry of an incorrect word, and correction information and controls also stored in memory for amending the incorrect word into a trial word which matches one stored in the above-mentioned dictionary. For greater efficiency and ease of use by the operator, if the trial word is satisfactory when displayed, pressing the usual return key on the keyboard signals the system to print that trial word in place of the incorrect word on a printed document, only the erroneous characters being replaced so as to minimize use of the correction ribbon and the print ribbon in unnecessary removal and replacement of valid characters in the incorrect word.

Abstract: A means for assuring ink ribbon and correction tape compatibility in a device which utilizes a first cassette having an ink ribbon therein and second cassette having a correction tape therein including a switch means in the device that controls the on-off condition of the device, and means located on one of the cassettes which will activate the on-off switch only when the device contains an ink ribbon in the first cassette which is functionally compatible with the correction tape in the second cassette, such as, for example, functional compatibility between a single-strike ink ribbon and a lift-off correction tape, or functional compatibility between a multiple-strike ink ribbon and a cover-up correction tape.

Abstract: A memory typewriter having an editable text stored in the memory together with a full-page correction buffer and individual counters associated with each differentiable word in the text. The combination permits determination and display of the most frequently used words in an edited text in order of descending frequency. Preferably, the combination includes a thesaurus list so that the typist can be altered if a frequently-used word in the display is also present in the thesaurus list. If so, the typist can then call for display of related synonyms by pressing or appropriate key controls and decide which of the synonyms, if any, to enter as replacement for the overused word.

Abstract: An electronic typewriter having a punctuation checking feature checks each punctuation feature as it is stored in a memory section, against a set of predetermined rules which define punctuation errors in terms of the context of the punctuation mark. If the punctuation mark does not agree with the defined rules, a suitable alarm, such as a visual and/or audible signal is given to the typist. A plurality of algorithms form the basis for sub-routines which a microprocessor can execute to determine if any of the rules are violated. The punctuation of a complete file can be checked by calling out each character in the file, from beginning to end and applying the checking procedure.

Abstract: A ribbon or tape tensioning system for typewriter correction ribbons includes a brake for exerting a braking force on a supply or feed ribbon spool. The mounting capstan for the feed spool is provided with a toothed hub which can be engaged by a pawl rotatably mounted on an arm which in turn is rotatably mounted on the typewriter frame. The pawl and the arm are provided with abutments or projections which when brought into contact with the frame cause the pawl to disengage or engage the toothed hub, thus permitting the hub to rotate freely or be braked. A force applied by an element such as a spring biases the assembly in a direction to cause the capstan to exert a tension on the ribbon, except when the pawl is disengaged. When the tension on the ribbon exceeds a predetermined amount, the pawl is disengaged from the toothed hub, permitting its momentary rotation and relief of the tension.

Abstract: A tape cassette has a sensing arm pivotally mounted therein biased against a correction tape on a take-up spool for sensing the amount of correction tape thereon. A correction tape feed mechanism mounted in a typewriter has a metering post for engaging the sensing arm at varying locations to cause the correction tape feed mechanism to feed the correction tape at substantially equal amounts regardless of the amount of correction tape on the take-up spool.

Abstract: The slide latch gravity lock of the present invention includes means which prevent the lock from opening when the article with which the lock is utilized is in its vertical position. When the article is moved from its horizontal position to a vertical position, a ball located within the lock mechanism moves by gravity from a first position wherein it does not restrain movement of the slide latch to a second position where it does.

Abstract: A keybutton guide assembly for a full sized keyboard with full travel keybuttons has a structure including a keybutton having a spring actuator engaging a spring finger at a location spaced away from a keybutton stem. This structure causes the keybutton stem to be guided only at an upper end of a stem guide boss for controlling the movement of a keybutton between rest and depressed positions with minimum rubbing friction.

Abstract: A word-processing system or memory typewriter having a list of commonly-confused words together with a definition for each word in the list and associated alternative words and their definitions, all stored in the memory. An audiovisual warning signal is generated upon each entry of a commonly-confused word so that the typist can press key controls to display definitions of the entered word and its alternatives. The list is of general applicability but, where specific ones of the commonly-confused words cause no concern to a particular typist, the controls may be individually modified by that typist to suppress issuance of the warning signal when these specific words are entered thereafter. Preferably, a Dictionary List of properly-spelled words is present in the system and utilized in controlling access to the list of commonly-confused words.

Abstract: A full sized electronic keyboard with full travel keybuttons provides switches for controlling an electronic typewriter or for controlling other devices. The keyboard has a structure designed for reducing part count and switch component part size and for simplifying assembly to minimize manufacturing cost. The structure has integral one piece parts for accommodating several keybutton actions. The integral one piece parts include a main frame, a sheet steel spring, a rubber dome switch member, and a printed circuit switch panel.

Abstract: A character display is pivotably mounted on an electronic typewriter for pivotable movement from an open position for viewing the character display to a closed position for covering the keyboard. The character display has a pivot axis in alignment with a rotatable axis of the platen. A structure for pivotably mounting the character display includes a spring operable to dampen the pivotable movement of the character display near the closed position. A brake pad combined with the dampening spring holds the character display in manually selected positions near the open position. A paper support which covers a platen and an adjacent open area is combined with the character display located in the closed position to provide a cover for the typewriter.

Abstract: A portable electronic typewriter having a memory incorporating a low-cost spelling-check dictionary and including a multi-character display. The typewriter is operable in a "List" mode according to which the operator can call up display of a portion of the dictionary, sequentially in alphabetical order and one word at a time. The display consists of each stored word sharing an initial set, or "string", of n characters (termed a "template") defined by the operator via the keyboard of the typewriter. In a preferred version, when the typist becomes aware of uncertainty as to spelling, the List Mode may be initiated either before or after partial entry of the desired word. In particular, if the characters entered include an erroneous one, (the typist being alerted of this by an audible alarm, for example), initiation of the List Mode thereafter causes the string to be truncated just before the erroneous character.

Abstract: A word-processing system or memory typewriter has the usual keyboard, input display and/or printer; together with a spelling dictionary stored within the memory, and an error signal generating device activated upon entry of an incorrect word. For greater efficiency and ease of use by the operator, the memory also stores several kinds of correction information--e.g., typographical correction, transposition reversal, phonetic substitutions, etc.--suitable for amending the incorrect word to display a trial word which matches one from the above-mentioned stored dictionary, the amending occurring by depression of a special key whenever entry of an incorrect word activates the error-signal device. Statistical control of selection of the class of correction information is provided, the order of utilization of the various classes depending upon the relative extent of the operator's prior successful usage of each class of information.

Abstract: A method and apparatus for adding a low-cost spelling check dictionary feature to document preparation systems such as portable electronic typewriters, the spelling check being performed on a character-by-character basis and an error signal emitted upon the earliest determination that an input character does not conform to that of any word listed in the dictionary. Semiconductor ROM is used for storage of the dictionary listing and for program control of the spelling check. Text compression methods are utilized to permit storage of large vocabularies (about 35,000 words) while minimizing the ROM capacity required (about 3 IC's of 256K bits each).

Abstract: A low-cost spelling-check dictionary apparatus for incorportation in a portable electronic typewriter. Semiconductor ROM is used for storage of the dictionary's word listing and for program control of the spelling check. Text compression methods are utilized to permit storage of large vocabularies (about 35,000 words) while minimizing the ROM capacity required (about 3 IC's of 256K bits each). In particular, the words are alphabetically arranged in a set of three interconnected tables together with extensions of the third table in highly compressed fashion. The tables verify the spelling order of the first three character inputs, while the extensions verify the fourth and subsequent inputs, if any. The tables have a first "look-up structure" format, whereas the extensions are arranged in a different "tree structure" type of format utilizing a "Huffman code" for the characters.

Abstract: The present invention is a typewriter lid actuated printing element homing device which uses a single switch for assuring that the printing element is engaged and maintained in its home position without any accompanying noise after the printing element is inserted, and also for assuring that the printing element is in its correct escapement position after the printing element is inserted. When the typewriter lid is closed, the carrier escapement position and the carrier motor phase is entered into memory. A latch member controlled by an actuator engages a notch in a flange of a rotating printing element drive gear for establishing the home position of the printing element. When the latch member engages the flange, the printing element drive gear motor is deenergized, stopping rotation of the drive gear, and the noise which would otherwise be caused by the print element drive motor continuously trying to rotate against the latch member is eliminated.