US2818958A - Escapement pawl control - Google Patents

Escapement pawl control Download PDF

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Publication number
US2818958A
US2818958A US556153A US55615355A US2818958A US 2818958 A US2818958 A US 2818958A US 556153 A US556153 A US 556153A US 55615355 A US55615355 A US 55615355A US 2818958 A US2818958 A US 2818958A
Authority
US
United States
Prior art keywords
pawl
carriage
interposer
rack
escapement
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
US556153A
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English (en)
Inventor
Thurston H Toeppen
Robert A Donnan
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.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
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 International Business Machines Corp filed Critical International Business Machines Corp
Priority to US556153A priority Critical patent/US2818958A/en
Priority to DEI12595A priority patent/DE1034661B/de
Priority to FR1179249D priority patent/FR1179249A/fr
Priority to GB39309/56A priority patent/GB843696A/en
Application granted granted Critical
Publication of US2818958A publication Critical patent/US2818958A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • B41J19/00—Character- or line-spacing mechanisms
    • B41J19/18—Character-spacing or back-spacing mechanisms; Carriage return or release devices therefor
    • B41J19/34—Escapement-feed character-spacing mechanisms
    • B41J19/42—Escapements having two pawls or like detents
    • 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
    • B41J19/00—Character- or line-spacing mechanisms
    • B41J19/02—Character- or line-spacing mechanisms with retarding devices, e.g. brakes
    • 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
    • B41J19/00—Character- or line-spacing mechanisms
    • B41J19/18—Character-spacing or back-spacing mechanisms; Carriage return or release devices therefor
    • B41J19/60—Auxiliary feed or adjustment devices
    • B41J19/62—Auxiliary feed or adjustment devices for back spacing

Definitions

  • This invention relates to typewriters, and more particularly to an improved pawl control mechanism for the escapement action of a typewriter carriage.
  • the escapement pawl In conventional typewriter escapement actions, the escapement pawl is pivotally mounted for rocking and longitudinal movement through the interaction of an elongated slot and pivot pin. With this conventional construction, when a pawl is tripped, it travels by spring action toward the next escapement rack tooth within the limits of its elongated slot, and then the escapement rack drives the pawl longitudinally so that the opposite end of the slot engages the support pin thereby terminating one escapement action.
  • Fig. 1 is a perspective view of a typewriter escapement control mechanism.
  • Figs. 2a through 2d are plan views showing the relation of the escapement mechanismwith a carriage rack during an escapement operation.
  • Fig. 3 is a plan view of both an escapement and backspace mechanism with a carriage rack.
  • this invention relates to an improved escapement pawl mechanism wherein a holding pawl which has pivotal but not longitudinal movement is used in conjunction with an interposer and latch control pawl to effect an escapement action.
  • a type bar 2 of a well known IBM type bar drive mechanism is shown pivotally mounted about a fulcrum 4 for movement under control of a cam lever 6 which is rocked about its own pivot 8 in response to the interengagement States atent of a cam 10 and power roller 12.
  • the cam 10 in turn, is rocked into engagement with the power roller via a key lever 14 actuating a trip latch 16.
  • U-bar 18 As the type bar is driven towards print position, it engages a U-bar 18 which is resiliently supported by a leaf spring 20 to permit limited transverse movement.
  • the U-bar 18 is equipped with a link 22, and during a print stroke, the transverse movement of the U-bar acting through link 22 rocks a trip lever 24 which is pivotally supported by a pin 26 for movement into and out of engagement with the escapement pawl mechanism 28.
  • a carriage escapement rack 30 is biased by the usual spring motor (not shown) in the direction of the arrow. Consequently, each time the pawl mechanism is released from the rack, the carriage advances under action of its spring motor relative to the pawl mechanism.
  • Pawl mechanism 28 (Figs. 2a-2d) comprises an interposer 32, a latch pawl 34 and a holding pawl 36, all superimposed and pivotally supported about a stud or pin 38 which is secured to the typewriter frame.
  • Each of the members of the pawl system is equipped with an ear 40, 42, 44 respectively engageable with a. corresponding spring 46, 48, 50 respectively to provide the necessary ro tational or translating force to the respective members.
  • the rack Since the rack is always to be held by the holding pawl 36, provision is made for pivoting the latter about pin 38 without permitting translation relative to it.
  • the latch pawl 34, and the interposer 32 are slotted to permit both pivotal movement as well as translation relative to pin 3%
  • the interposer 32 has a trip ear or shoulder 33 engageable with the trip lever 24. .In the normal or rest positions of Fig. 2a, the trip ear 33 will act on the tails of both the latch pawl 34 and the holding pawl 36 to pivot them.
  • the latch pawl 34 (upper one) is slotted at its pivot point so that the distance from the right hand end of its pivot slot to its rack tooth holding surface (or nose) is less than that of the holding pawl 36 thereby, assuring the fact that in rest position (Fig. 2a), the holding pawl is the only one blocking movement of the rack 30.
  • Thenose of the latch pawl 34 is slightly shorter than that of the holding pawl 36, therefore, when the two pawls are pivoted about pin 38, the latch pawl nose is free of the rack 30 slightly before holding pawl nose and, therefore, can be tripped, i. e. pulled to the right by its spring 48.
  • Fig. 2a shows the rest position of the parts with the nose of latch pawl 34 and hold pawl 36 engaging rack tooth 52
  • the trip lever 24 has moved forward to rock the interposer 32 which, in turn, pivots the latch pawl 34, and the hold pawl 36, to the point where the latch pawl is tripped and slides over the tooth 52 under the action of its spring 48, but the holding pawl 36 is still not quite out of engagement of the tooth 52.
  • the tail of the latch pawl 34. is free of the interposer trip ear 33.
  • the relative positions of the escapement trip lever 24 with respect to the latch pawl 34 is such that the two can never be in engagement, and consequently, it is impossible for the rack to be held by the tail of latching pawl 34 being wedged against the side of the trip lever 24 when the latter has been moved to a tripping position.
  • the latch pawl hold the rack if a type bar is held in printing position, since the latch pawl, as previously described will unlatch the holding pawl from the trip ear 33 of the interposer 32.
  • the ear 33 of interposer 32 will engage only the tail of holding pawl 36, since the latch pawl is already in its Fig. 2b position.
  • the backspace mechanism is under control of a key lever 64 which is connected via a link 66 to a trip lever 68 of a backspace cam mechanism 70.
  • the latter is pivotally supported about a fulcrum 72 for engagement of a cam 74 with the power roll 12.
  • the cam is rocked into engagement with the power roll to be driven through a half revolution whereupon the cam holder 70 is rocked to pull on link 76 and then via bell crank 78 to pull on link 56, for the backspace action heretofore described.
  • an improved pawl control for the escapement action of the carriage comprising an interposer, means pivotally mounting the same for movement into and out of a tripping position, said interposer being further provided with means permitting transverse movement relative to said pivotal mounting means, a holding pawl mounted for pivotal movement only with respect to said mounting means from a rest position wherein it is biased into en gagement with said rack to a release position, means interconnecting said interposer and said holding pawl to lift said holding pawl out of said rack in response to said interposer being moved to tripping position, and means responsive to carriage movement during an escapement action for disengaging said interposer from said holding pawl to permit the latter to re-engage said carriage rack.
  • an improved pawl assembly for regulating the spacing of said carriage comprising a holding pawl, an unlatching pawl, and an interposer all mounted for tripping movement during an escapement action with said pawls being movable from a rest position wherein they are biased into engagement with said carriage rack through a tripping range to a rack release position, said unlatching pawl and said interposer being further provided with means permitting transverse movement relative to said holding pawl, said interposer being still further provided with portions engageable with both pawls to trip the same during an escapement action, said unlatching pawl when tripped having means biasing the same in a direction opposite to carriage travel and free of said interposer portions so that said unlatching pawl may again be biased into engagement with said carriage rack whereupon, as said carriage moves during an escapement action, said unlatching pawl is driven into engagement with said interposer to un
  • an improved escapement action having an escapement pawl cluster comprising a holding pawl, an unlatching pawl, and an interposer with all of said parts being mounted for tripping movement from a rest position wherein said pawls are biased into said carriage rack to a trip position wherein said pawls are disengaged from said rack thereby releasing the latter for movement, said interposer having portions engageable with said pawls to trip the same when said pawl cluster is in grouped position, said interposer being biased into cluster grouped position while said unlatching pawl is biased normally out of grouped position but is driven into cluster grouped position by said carriage during an escapement operation, said unlatching pawl in being driven back into cluster grouped position being engageable with said interposer when the latter is in its tripping range to drive the same out of grouped position thereby permitting said holding pawl to re-engage said rack.
  • an improved escapement action having a pawl cluster comprising a holding pawl, an unlatching pawl, and an interposer, means mounting said holding pawl for pivotal movement only while said unlatching pawl and said interposer are mounted for both pivotal and transverse movement, said interposer having portions engageable with said pawls when said cluster is in grouped position to trip the same from a rest position wherein said pawls are biased into said rack to a trip position wherein said pawls are disengaged from said rack thereby releasing the latter for movement, said interposer being biased normally into cluster grouped position while said unlatching pawl is biased normally out of cluster grouped position but driven into cluster grouped position by said carriage during escapement, said unlatching pawl in being driven to grouped position being engageable with said interposer when the latter is in its tripping range to drive the same out of groupingposition thereby permitting said holding
  • an improved pawl control for the escapement action of the carriage comprising a holding pawl, means mounting the same for pivotal movement only and including means biasing the same into engagement with said carriage, an interposer operable during each escapement action to trip said holding pawl free of said carriage, and an unlatching pawl engageable with said interposer during an escapernent action, said unlatching pawl being biased into engagement with said carriage and having provision for biased longitudinal movement relative to said mounting means to be free of said interposer after being tripped until said carriage advances in letter spacing operation whereupon said unlatching pawl will strike said interposer if the latter is in its tripping range to disengage the same from said holding pawl to permit the latter to drop back into carriage engagement.
  • an improved pawl arrangement for the escapernent action of the carriage comprising a sup porting stud, an interposer pivotally mounted for movement from a rest position into a tripping position about said supporting stud during an escapement action, said interposer being further provided with means to permit transverse movement with respect to the direction of said tripping action, spring means biasing said interposer normally in one direction of said transverse motion, and a holding pawl mounted on said supporting stud for pivotal movement from a rest position wherein it is biased into engagement with said carriage to a tripping position wherein said carriage is free for movement, said holding pawl being engageable with said interposer only when the latter is biased in its normal direction whereby during an escapement action as said interposer is driven into tripping position, said holding pawl is lifted out of said carriage to release the same for escapement.
  • a mechanism in accordance with claim 6 being further provided with means responsive to carriage move ment during an escapement action for disengaging said interposer from said holding pawl thereby permitting the latter to drop back into the carriage.
  • a mechanism in accordance with claim 6 being further equipped with an unlatching pawl which is pivotally supported about said mounting stud for transverse movement and pivotal movement from a carriage engaging position to a trip position in response to said interposer being moved to tripping position, said unlatching pawl when in its trip position being spring biased out of engagement with said interposer whereupon said carriage rack drives said unlatching pawl into said interposer thereby unlatching said interposer from said holding pawl permitting the latter to drop into the carriage.

Landscapes

  • Accessory Devices And Overall Control Thereof (AREA)
  • Character Spaces And Line Spaces In Printers (AREA)
US556153A 1955-12-29 1955-12-29 Escapement pawl control Expired - Lifetime US2818958A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US556153A US2818958A (en) 1955-12-29 1955-12-29 Escapement pawl control
DEI12595A DE1034661B (de) 1955-12-29 1956-12-20 Zahnstangenschrittschaltwerk fuer den Papierwagen von Schreib- und aehnlichen Maschinen
FR1179249D FR1179249A (fr) 1955-12-29 1956-12-21 échappement à cliquet
GB39309/56A GB843696A (en) 1955-12-29 1956-12-27 Improvements in or relating to typewriters

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US843696XA 1955-12-29 1955-12-29
US1179249XA 1955-12-29 1955-12-29
US1034661XA 1955-12-29 1955-12-29
US556153A US2818958A (en) 1955-12-29 1955-12-29 Escapement pawl control

Publications (1)

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US2818958A true US2818958A (en) 1958-01-07

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US556153A Expired - Lifetime US2818958A (en) 1955-12-29 1955-12-29 Escapement pawl control

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US (1) US2818958A (de)
DE (1) DE1034661B (de)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3048313A (en) * 1958-06-20 1962-08-07 Gen Electric Automatic wire-breaking device
US3223220A (en) * 1963-03-13 1965-12-14 Marx & Co Louis Typewriter having sliding universal member
US3288262A (en) * 1962-11-08 1966-11-29 Olivetti & Co Spa Variable spacing mechanism for typewriters and like machines
US3346088A (en) * 1965-06-30 1967-10-10 Ibm Carrier mechanism for proportional escapement typewriter
US3346089A (en) * 1965-06-30 1967-10-10 Ibm Carrier mechanism for proportional escapement typewriter
US3346086A (en) * 1963-09-25 1967-10-10 Ibm Proportional escapement apparatus for a single element typewriter
US3346091A (en) * 1965-06-30 1967-10-10 Ibm Tabulation apparatus for typewriter
DE1253287B (de) * 1962-01-18 1967-11-02 Olympia Werke Ag Elektromagnetische Proportionalschritt-Steuerung fuer Schreibmaschinen
US3366215A (en) * 1965-07-28 1968-01-30 Ibm Single rack backspace
DE1293168B (de) * 1963-06-26 1969-04-24 Ibm Teilschrittschalteinrichtung fuer den Wagen von Schreib- und aehnlichen Maschinen
US3519115A (en) * 1967-09-11 1970-07-07 Singer Co Escapement mechanism responsive to the return portion of a reciprocal rotary motion
US3752289A (en) * 1969-12-31 1973-08-14 Triumph Werke Nuernberg Ag Typewriter escapement and control devices therefor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1994544A (en) * 1930-03-13 1935-03-19 Electromatic Typewriters Inc Typewriter
US2536619A (en) * 1948-03-26 1951-01-02 Underwood Corp Escapement mechanism for typewriting and like machines

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE280042C (de) *

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1994544A (en) * 1930-03-13 1935-03-19 Electromatic Typewriters Inc Typewriter
US2536619A (en) * 1948-03-26 1951-01-02 Underwood Corp Escapement mechanism for typewriting and like machines

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3048313A (en) * 1958-06-20 1962-08-07 Gen Electric Automatic wire-breaking device
DE1253287B (de) * 1962-01-18 1967-11-02 Olympia Werke Ag Elektromagnetische Proportionalschritt-Steuerung fuer Schreibmaschinen
US3288262A (en) * 1962-11-08 1966-11-29 Olivetti & Co Spa Variable spacing mechanism for typewriters and like machines
US3223220A (en) * 1963-03-13 1965-12-14 Marx & Co Louis Typewriter having sliding universal member
DE1293168B (de) * 1963-06-26 1969-04-24 Ibm Teilschrittschalteinrichtung fuer den Wagen von Schreib- und aehnlichen Maschinen
US3346086A (en) * 1963-09-25 1967-10-10 Ibm Proportional escapement apparatus for a single element typewriter
US3346088A (en) * 1965-06-30 1967-10-10 Ibm Carrier mechanism for proportional escapement typewriter
US3346089A (en) * 1965-06-30 1967-10-10 Ibm Carrier mechanism for proportional escapement typewriter
US3346091A (en) * 1965-06-30 1967-10-10 Ibm Tabulation apparatus for typewriter
US3366215A (en) * 1965-07-28 1968-01-30 Ibm Single rack backspace
US3519115A (en) * 1967-09-11 1970-07-07 Singer Co Escapement mechanism responsive to the return portion of a reciprocal rotary motion
US3752289A (en) * 1969-12-31 1973-08-14 Triumph Werke Nuernberg Ag Typewriter escapement and control devices therefor

Also Published As

Publication number Publication date
DE1034661B (de) 1958-07-24

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