US3788443A - Character selection and impression control mechanism for typewriter - Google Patents

Character selection and impression control mechanism for typewriter Download PDF

Info

Publication number
US3788443A
US3788443A US00225532A US3788443DA US3788443A US 3788443 A US3788443 A US 3788443A US 00225532 A US00225532 A US 00225532A US 3788443D A US3788443D A US 3788443DA US 3788443 A US3788443 A US 3788443A
Authority
US
United States
Prior art keywords
pulleys
carriage
typewriter
movement
printing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00225532A
Other languages
English (en)
Inventor
U Menzi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Paillard SA
Original Assignee
Paillard SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Paillard SA filed Critical Paillard SA
Application granted granted Critical
Publication of US3788443A publication Critical patent/US3788443A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J5/00—Devices or arrangements for controlling character selection
    • B41J5/08—Character or syllable selected by means of keys or keyboards of the typewriter type
    • B41J5/18—Locks
    • B41J5/22—Interlocks between keys, e.g. without detent arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J1/00—Typewriters or selective printing mechanisms characterised by the mounting, arrangement or disposition of the types or dies
    • B41J1/60—Typewriters or selective printing mechanisms characterised by the mounting, arrangement or disposition of the types or dies with types or dies on spherical, truncated-spherical, or like surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J7/00—Type-selecting or type-actuating mechanisms
    • B41J7/54—Selecting arrangements including combinations, permutation, summation, or aggregation means
    • B41J7/56—Summation devices for mechanical movements
    • B41J7/64—Pulley and strand mechanism

Definitions

  • bails control the decoding device for the charac- 2,757,775 8/1956 l-lickerson 197/49 Selection and an additional bail Controls the device 2,769,029 10/1956 Howard 197/49 X for the No-print function.
  • Still another bail controls 2,879,876 3/1959 Palmer et a1 r .r 19.7/16 h hig and low p n g l y- One or h other of 2,919,002 12/1959 Palmer r 197/16 these two last mentioned bails, or both simultaneously,
  • H PMENTEB ME 2 8 $74 sum 7 or 7 CHARACTER SELECTION AND IMPRESSION CONTROL MECHANISM FOR TYPEWRITER FIELD OF THE INVENTION
  • This invention relates to typewriters and more particularly to a character selection and impression control mechanism for a typewriter of the kind comprising at least one printing element on the surface of which a plurality of the characters of a type front are positioned.
  • This kind of machine comprises a typewriter having a single element printing head wherein all the characters of the type font are positioned on the surface of said printing head.
  • characters may be considered as being distributed along a certain number of columns'and lines.
  • a character selection mechanism is provided to present one character at a time to a single printing position, an impression control mechanism being provided to bring the selected character in printing engagement with a paper carrier.
  • a selection operation requires first moving the printing element or elements to present one of said surface portions for the selection of characters, an operation that is generally called a shift operation, then moving the printing element or elements within the area of the portion presented for the selection of one particular character.
  • Thei mpression control mechanism is effective to establish the proper printing velocity in accordance with the area of each character, so that a desirable impression on the paper is achieved. Generally, two different printing velocities are considered adequate.
  • the impression control mechanism is further effective to establish a No-print" mode under certain circumstances.
  • the character selection mechanism is generally controlled from the keyboard through a coding mechanism associating with the actuation of any character key a unique combination of impulses on a determined number of bails.
  • a converter or decoding mechanism is then provided for transforming the coded impulses on these bails into analog coordinate displacement for positioning the printing element or elements.
  • a further common feature of typewriters of this kind is that the paper feed unit remains stationary while the printing element, or elements, is supported on a carriage which is movable across the page. All the information concerning the selection and the impression control mechanism are thus to be transmitted from the frame of the machine to this carriage.
  • the general design of the typewriter is very much determined by the conception of the means associated with this transmission.
  • the shift, the printing velocity and the No-print functions are still controlled by different mechanisms whose coding and or decoding devices, when present, and or transmission elements between the frame and the carriage, are different in design and in location on the machine.
  • typewriters of this design do not allow a complete adjustment and checking of all the functions installed on the carriage before a practically complete assembling of the machine.
  • one of the objects of this invention to provide an integrated system of transmission between the frame and the carriage of a typewriter of the kind described for the transmission of the orders controlling the character selection, the shift, the printing velocity and the No-print functions. 7
  • Another object of the invention is to provide an integrated system of transmission allowing the design of a carriage incorporating the devices for performing these different functions as a largely independant module allowing the complete adjustment and checking of said functions before the final assembling of this carriage on the typewriter.
  • a still further object of the invention is to provide a character selection mechanism with simple means adapted for cyclically moving the printing element or elements in two opposite directions forthe selection of a surface portion as well as for the selection of a character.
  • a character selection and impression control mechanism is provided with an integrated coded mechanical system of transmission for the orders controlling the character selection, the shift, the printing velocity and the No-print functions, between the frame of a typewriter and converter or decoding means supported on the carriage and controlling the devices performing these functions on said carriage.
  • This system of transmission comprises a definite number of bails mounted on said frame for relative movements thereon and each adapted to cooperate with control means supported by the carriage for all the positions of said carriage along a line of writing.
  • a number of said bails control the decoding device for the character selection and a additional controls the device for the No-print function.
  • Still another bail controls the high and low printing velocity.
  • FIG. 1 is a side elevation of a portion of the carriage of the typewriter showing the single head printing mechanism.
  • FIG. 2 is a schematic view of the column selection on the single element print head.
  • FIG. 3 is a top plan view of a portion of the carriage, showing the column selection mechanism.
  • FIGS. 4 and 5 represent parts of FIG. 3 for different phases of the cyclical operation.
  • FIGS. 6 and 7 are side elevations of parts of FIGS. 3, 4 and 5.
  • FIGS. 8, 9 and 10 are side elevations of a portion of the carriage for different phases of the cyclical operation.
  • FIG. 11 is a perspective view, on a larger scale, of a part of FIG. 8.
  • FIG. 12 is a rear elevation of the carriage.
  • FIG. 13 is also a rear elevation of the carriage during another phase of the shift cycle.
  • FIG. 14 is a top plan view of a portion of the carriage with the printing velocity control mechanism.
  • FIG. 15 and 16 are side elevations of portions of the carriage with control bails.
  • FIG. 17 and 18 are elevations of the left side of the carriage showing different positions of the shift control mechanism. 1
  • FIG. 19 is a similar to FIGS. 4 and 5 showing a shift operation.
  • the kind of typewriter with a single element print head chosen as an application is well known in the art, thus a complete and detailed description of all the associated mechanism is not considered necessary for the full understanding of the invention.'
  • the single element print head illustrated has the form of a truncated sphere whose upper and lower end planes are perpendicular to the polar axis XX. All the characters and signs to be printed, here a total number of 96, are arranged on the face 2 of the print element in four rows, parallel to the end planes of the head, and 24 columns.
  • the print head 1 is mounted upon a carriage 3 which is slidably supported on a cycle shaft 5 journaled on the frame of the typewriter, not shown, and by a stationary bar 6, both extending parallel to the platen 4.
  • the print head is rotatably mounted on a hollow post 7 fastened to a rocker platform 8 that is pivotably mounted between the two side walls 9 and 10 of the carriage 3 to oscillate about an axis U, parallel to the axis Z of the platen.
  • any one of the 24 columns numbered 5 to 18 on the print head may be presented in the printing position P by moving one or several pulleys 15, 16, 17, 18 and 19 radially between a normal rest position and an active position illustrated in dotted lines, extending or contracting the effective length of tape 13.
  • columns 7 to 18 may be presented in the printing position by adding l2 units of rotation, corresponding to on the print head, to the values corresponding to columns S to 6.
  • a shift operation is performed by moving pulley 15 a distance of 12 units to the left.
  • Each pulley is associated with a lever adapted to transform a unitary control stroke into a radial displacement of given length and direction of the corresponding pulley.
  • the selector latch 30 has an elongated portion 30 of reduced width guided in a notch 31 on a guide plate 32 fastened to base plate 20. Its free end 30 which is broader, is engaged between the lips 33 of a notch 33 cut in a coupling slide 34.
  • a double arm 47 fastened by screw 48 to the selector latch control lever 49, supports two cam rollers 43 and 44 rotatably mounted on studs 45 and 46 and cooperating respectively with cams 41 and 42 in such a way that for each cyclical 360 rotation of shaft 5, in the direction of arrow f the selector latch control lever 49 performs a complete oscillation ,8
  • the lever 53 rotatably supporting pulley 19, is pivoted on a stud 54 of the base plate 20.
  • the corresponding selector latch 55 hinged at 56 on lever 53, has a free end 55 of reduced width forming a notch 55 This free end extends through a hole 57 in the selector latch control plate 51 with notch 55 bearing on this plate under the tension of the tape acting on pulley 19.
  • the coupling slide 62 If, at the beginning of a selection cycle, the coupling slide 62 is brought to its lower position, the latch member 60 will be tilted downwardly and its free end will clear the way to the extremity 55 0f the selector latch 55 allowing it, under the tension of tape 13, to follow the selector latch control plate 51 in its cyclical oscillation.
  • a certain number of the coupling slides, such as 62, are each directly controlled by a bail, such as 64 in F IG. 1.
  • These bails belong to a group of bails extending parallel to the axis Z of the platen along the whole travel of the carriage. They are pivoted on the frame of the typewriter at their two ends.
  • PRINTING MECHANISM This mechanism controls the oscillation of the rocker platform 8.
  • the side wall 8 of the rocker platform supports a stud 65 cooperating with the free end 66 of a control arm 66 pivoted on a stud 67 fastened to the side wall 9 of carriage 3.
  • the roller 69 By sliding the arm 71 against the action of spring 73, the roller 69 may be positioned opposite a low velocity print cam 75. A further displacement of arm 71 will position arm 71 opposite a No Print cam 76 with no rise or a negligible rise.
  • Two additional bails 77 and 81 (see FIGS. 15 and 16) and two coupling slides 78 and 82 are provided for the control of the printing mechanism.
  • an impulse is transmitted from bail 77 to the coupling slide 78 to bring it into its lower position illustrated in FIGS. 13 and 15.
  • this lever 79 is rotated counter-clockwise and, through a second arm 79 hinged at '71 on the sliding arm 71, this latter is shifted to the left to position the roller 69 opposite low velocity cam 75.
  • the impulses on the bails, controlled by a cycle mechanism are generally of a short duration as compared to the duration of a complete cycle. For this reason, a latching mechanism has been provided to maintain the roller 69 opposite the desired cam, 75 or 76, during the major part of a cycle.
  • the coupling slide 78 cooperates further through a nose 78 with the arm 91 of a second lever 91 pivotally supported at 92 on the cross-piece 38.
  • a downward movement of the slide causes a clockwise rotation of lever 91.
  • lever 91 With its other arm 91 protruding on the outside of the side wall 10, it cooperates with the arm 93 of an other lever 93 pivotally mounted at 94 on this side wall to rotate this lever 93 in a counter-clockwise direction against the action of spring 93 as illustrated in FIGS. 17 and 18.
  • the trigger 95 is slidably mounted on a stud 97 of baseplate 20 and guided by the opening 96.
  • the pulley 15 When the pulley 15 is brought to its active 12 units position by the lever 26,27 (see FIG. 4), the trigger 95 will be pushed forward by the stud 28 on said lever against the action of a leaf spring 98 fastened to side wall 10.
  • the trigger 95 is able to slide freely through a notch 99 of a second leaf spring 99 fastened at 99 on a third leaf spring 100 fastened at 100 on side wall 10, as illustrated in FIGS. 4 and 17, or, according to FIGS. 18 and 19, it will strike against leaf spring 99 and bend it with leaf spring 100 away from side wall 10.
  • a shift latch cam 101 of a generally circular shape is fastened at 102 to the third leaf spring 100 and extends through an opening 103 of side wall 10 to the inside of the carriage.
  • the two arms 22 and 23 of the lever 22,23 supporting the pulley are moving in the direction of arrow f They are first elastically drawn aside by the cam 101 befor snapping into twonotches 101 and 101 of said cam.
  • lever 83 positions, through lever 79 and sliding arm 71, roller-69 opposite the No Print cam 76. Simultaneously, theraised arm 83 of lever 83 allow the coupling slide 34 to reach its upper position under the action of its spring as illustrated on FIG. 3 and 13.
  • the selector latch control plate 51 advances to its forward position over an angle ,8 as illustrated on FIG. 10.
  • lever 93 which has been rotated counterclockwise under the action of lever 91 to the position 9 illustrated in FIG. 17, has guided through its forkshaped extremity 9.3 the trigger 95 towards notch 99 of leaf spring 99 through which it is freely sliding. At the end of the counter-clockwise rotation of lever 22,23, its two arms 22 and 23 are then latched on the non-displaced shift latch cam 101.
  • selector latch control plate 51 oscillates back to its initial rest position, as well as selector latches 30 and 55 and their associated levers 26,27 and 53.
  • the 12 units pulley 15 remains in its latched position as illustrated in FIG. 5, when the 6 units pulley 19 returns to its rest position, rotating the print head of a further amount of 6 units.
  • the coupling slides 78 and 82 which had been latched during the major part of the cycle in their lower position, resume their rest position as well as levers 79, 83, 91 and 93.
  • the typewriter is thus ready to perform a normal selection-printing cycle for the characters associated to columns 7 to 18 of the print head.
  • lever 26, 27 rotates counter-clockwise driving the trigger 95 to the outside.
  • the fork-shaped end 93 of lever 93 is now maintaining the free end of the trigger 95 at a higher level, it will hit the leaf spring 99 and push it back together with leaf spring 100 and cam 101 as illustrated in FIG. 19, unlatching the arms 22 and 23 of lever 22,23.
  • the lever 22,23 will thus be free to follow the clockwise rotation of lever 26,27 to its rest position.
  • the coordinated action of the 6 units pulley 19 allows a two step return operation, each time of six units, instead of a one step'twelve unit operation in half the time, thus decreasing substantially the accelerations.
  • a typewriter comprising a platen (4), a driving shaft (5) extending parallel to said platen and adapted to rotatable for a definite angular value during each print cycle, a carriage (3) movable along said shaft (5) along a line of writing and carrying at least one printing element (1) having a plurality of characters on its surface (2) distributed into two groups, a shift device which permits selection at will of one of said two groups of characters, a selection device for bringing one of the characters of the group selected into printing position, an impression control device comprising means to impart at least two different printing velocities to said printing element (1), and means to establish a print or no-print mode during an operating cycle, a coding device supplying orders coded in the form of impulses through the actuation of the keys of the typewriter keyboard, a decoding device comprising a set of pulleys (15-19) movable with respect to each other and controlling a pulley (12) selectively rotatably driving the printing element (1) by means of a flexible tape (13
  • said coded order transmission device comprises two universal bars (81, 77) controlling said shift device, the first universal bar (81) controlling the shift function, the second universal bar (77) controlling the locking of said shift device as well as said impression control device.
  • the means for moving the pulleys (1549) of said set of pulleys comprises linking elements (30) for each pulley, wherein said pulleys (1549) are driven by a single actuating member (49) also mounted on said carriage (3), said actuating member (49) controlled by said driving shaft (5) and having a cyclical reciprocating movement imparted thereto, movement transforming means for each linking element (30) provided on said carriage (3) so as to transform movements of approximately equal amplitudes of said linking elements (30) into movements of different amplitudes of said pulleys (15-19), coupling elements (34) also mounted on the carriage (3), each said coupling element acting upon a linking element (30) and capable of assuming two positions, a first position in which the corresponding linking element (30) is susceptible of being driven by the actuating member (49) and controls a movement of specific amplitude of the corresponding pulley (15), a second position in which the corresponding linking element (30) is not susceptible of being driven by said actuating member (49
  • a typewriter wherein means are provided to impart to the corresponding pulley at the beginning of the printing cycle, a movement acting on the length of the free portion of the flexible tape (13), comprising a movable stop movable by a coupling element (62) and susceptible of assuming two positions under the action of the corresponding universal bar (64), a first position in which the stop (60) is in the way of the linking element (55) preventing the latter from following the movement of the single actuating member (49), a second position in which said stop (60) is out of the way of said linking element (55), the latter then being capable of following the movement of the actuating member (49) under the action of the tension of the flexible tape (13).
  • a typewriter according to claim 3, wherein the movement transforming elements each comprise a' gral with the'carriage (3) of the typewriter, some of said levers supporting, on the one hand, one of the pulleys of the set of pulleys and hinged, on the other hand, to one of the linking elements (30), at least one of the pulleys (15) of the set of pulleys being supported by an element (22, 23) hinged on base plate one arm of the corresponding movement transforming lever (26) being susceptible of acting on said element under action of the corresponding linking element (30) hinged on said lever to control the movement of specific amplitude of said pulley.
  • impression control means are associated with the control means of the shift device, said shift device being convice (91, 93, 95, 99, 101) forthe arms of the movement transforming lever (22, 23), so as to retain beyond the duration of a printing cycle at least one of the pulleys (15) of said set of pulleys in a position corresponding at least approximately to the maximum amplitude of its movement under the action of the cyclical reciprocating movement of said actuating member (49).

Landscapes

  • Character Spaces And Line Spaces In Printers (AREA)
  • Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
US00225532A 1971-02-12 1972-02-11 Character selection and impression control mechanism for typewriter Expired - Lifetime US3788443A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH211971A CH534054A (fr) 1971-02-12 1971-02-12 Mécanisme de sélection pour machine à écrire à élément de frappe unique

Publications (1)

Publication Number Publication Date
US3788443A true US3788443A (en) 1974-01-29

Family

ID=4226310

Family Applications (1)

Application Number Title Priority Date Filing Date
US00225532A Expired - Lifetime US3788443A (en) 1971-02-12 1972-02-11 Character selection and impression control mechanism for typewriter

Country Status (5)

Country Link
US (1) US3788443A (de)
CH (1) CH534054A (de)
DE (1) DE2207413A1 (de)
FR (1) FR2126882A5 (de)
GB (1) GB1350563A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3871505A (en) * 1972-10-13 1975-03-18 Olympia Werke Ag No-print key control
US3973488A (en) * 1974-02-04 1976-08-10 Oscar Adolf Engelbert Wallmark Printing unit particularly intended for price labelling machines
US4192619A (en) * 1974-07-29 1980-03-11 Redactron Corporation Electronically controlled printer system
US4215943A (en) * 1978-06-21 1980-08-05 Redactron Corporation Motor driven single element printer
US4348121A (en) * 1978-02-07 1982-09-07 Hermes Precisa International S.A. Strike and non-strike impact control mechanism for typewriter
US4359287A (en) * 1979-04-17 1982-11-16 Silver Seiko, Ltd. Impression control mechanism for a typewriter
US4568208A (en) * 1983-10-20 1986-02-04 Brother Kogyo Kabushiki Kaisha Printer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2050950A (en) * 1979-06-19 1981-01-14 Hermes Precisa International Printing selection and control mechanism for a typewriter
US6467824B2 (en) * 2001-03-13 2002-10-22 Data I/O Corporation Floating seal pick and place system and unit therefor

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2757775A (en) * 1953-01-19 1956-08-07 Ibm Single printing element typewriter
US2769029A (en) * 1954-05-27 1956-10-30 Teleprinter Corp Telegraph printer
US2879876A (en) * 1955-11-17 1959-03-31 Ibm Single element printing machine
US2919002A (en) * 1957-04-19 1959-12-29 Ibm Selection mechanism for a single printing element typewriter
US3239049A (en) * 1962-06-27 1966-03-08 Ibm Impression control mechanism automatically selecting one of a plurality of cams
US3348648A (en) * 1966-08-08 1967-10-24 Royal Typewriter Co Inc Keyboard providing serial generation of two different codes responsive to one key depression
US3382963A (en) * 1966-08-17 1968-05-14 Ibm Printing apparatus with no-print feature
US3451520A (en) * 1967-06-21 1969-06-24 Ibm Ribbon level shift with print velocity selection
US3618736A (en) * 1969-12-22 1971-11-09 Ibm Variable force impact printer with backspace mechanism

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2757775A (en) * 1953-01-19 1956-08-07 Ibm Single printing element typewriter
US2769029A (en) * 1954-05-27 1956-10-30 Teleprinter Corp Telegraph printer
US2879876A (en) * 1955-11-17 1959-03-31 Ibm Single element printing machine
US2919002A (en) * 1957-04-19 1959-12-29 Ibm Selection mechanism for a single printing element typewriter
US3239049A (en) * 1962-06-27 1966-03-08 Ibm Impression control mechanism automatically selecting one of a plurality of cams
US3348648A (en) * 1966-08-08 1967-10-24 Royal Typewriter Co Inc Keyboard providing serial generation of two different codes responsive to one key depression
US3382963A (en) * 1966-08-17 1968-05-14 Ibm Printing apparatus with no-print feature
US3451520A (en) * 1967-06-21 1969-06-24 Ibm Ribbon level shift with print velocity selection
US3618736A (en) * 1969-12-22 1971-11-09 Ibm Variable force impact printer with backspace mechanism

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3871505A (en) * 1972-10-13 1975-03-18 Olympia Werke Ag No-print key control
US3973488A (en) * 1974-02-04 1976-08-10 Oscar Adolf Engelbert Wallmark Printing unit particularly intended for price labelling machines
US4192619A (en) * 1974-07-29 1980-03-11 Redactron Corporation Electronically controlled printer system
US4348121A (en) * 1978-02-07 1982-09-07 Hermes Precisa International S.A. Strike and non-strike impact control mechanism for typewriter
US4215943A (en) * 1978-06-21 1980-08-05 Redactron Corporation Motor driven single element printer
US4359287A (en) * 1979-04-17 1982-11-16 Silver Seiko, Ltd. Impression control mechanism for a typewriter
US4568208A (en) * 1983-10-20 1986-02-04 Brother Kogyo Kabushiki Kaisha Printer

Also Published As

Publication number Publication date
GB1350563A (en) 1974-04-18
CH534054A (fr) 1973-02-28
DE2207413A1 (de) 1972-08-24
FR2126882A5 (de) 1972-10-06

Similar Documents

Publication Publication Date Title
US2919002A (en) Selection mechanism for a single printing element typewriter
US3239049A (en) Impression control mechanism automatically selecting one of a plurality of cams
US3788443A (en) Character selection and impression control mechanism for typewriter
US3382963A (en) Printing apparatus with no-print feature
US3618736A (en) Variable force impact printer with backspace mechanism
US4239400A (en) Electronically controlled printing unit
US3666070A (en) Differential mechanism for positioning a type character on a type element
US3620344A (en) Selection system for a dual-element typewriter
US3677384A (en) Mechanism for positioning single element type carriers
US3888339A (en) Impression control mechanism for a typewriter or similar machine
US3718243A (en) Apparatus for storing typing commands given in too rapid succession by keys
US3237747A (en) Cam operated ribbon vibrator and ribbon feed mechanism
US3021937A (en) Selective interlock mechanism
US3355000A (en) Type bar actuating mechanism with separate drive and actuating bell cranks
US3592313A (en) Encoding keyboard having dual-output shift key
US3311211A (en) Keyboard sequence discriminator with different codes for upper and lower case
US3754631A (en) Positioning typewriter
US3028942A (en) Escapement mechanism
US2905301A (en) Cam operated code setup mechanism
US3592309A (en) Cyclically operable typewriter
US3780845A (en) Power driven typewriter with single type head
US3467233A (en) Mechanism for positioning a spheroidal type head to present a selected type to a print position
US3581860A (en) Method and apparatus for shifting a typing element
US3978967A (en) Typewriter tabulator
US3524527A (en) Alternate character selection mechanism for typewriters