US3893561A - Half backspace for dual pitch typewriter - Google Patents

Half backspace for dual pitch typewriter Download PDF

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Publication number
US3893561A
US3893561A US418349A US41834973A US3893561A US 3893561 A US3893561 A US 3893561A US 418349 A US418349 A US 418349A US 41834973 A US41834973 A US 41834973A US 3893561 A US3893561 A US 3893561A
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US
United States
Prior art keywords
camming
rack
movement
escapement 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
US418349A
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English (en)
Inventor
John Gilbert Gibbons
Raymond Michael Marowski
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.)
IBM Information Products 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 US418349A priority Critical patent/US3893561A/en
Priority to GB4033374A priority patent/GB1436516A/en
Priority to FR7434701A priority patent/FR2252221B1/fr
Priority to IT28317/74A priority patent/IT1022789B/it
Priority to JP11831274A priority patent/JPS544289B2/ja
Priority to CA211,472A priority patent/CA1014504A/en
Priority to CH1523974A priority patent/CH575299A5/xx
Priority to DE2455580A priority patent/DE2455580C3/de
Application granted granted Critical
Publication of US3893561A publication Critical patent/US3893561A/en
Assigned to MORGAN BANK reassignment MORGAN BANK SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: IBM INFORMATION PRODUCTS CORPORATION
Assigned to IBM INFORMATION PRODUCTS CORPORATION, 55 RAILROAD AVENUE, GREENWICH, CT 06830 A CORP OF DE reassignment IBM INFORMATION PRODUCTS CORPORATION, 55 RAILROAD AVENUE, GREENWICH, CT 06830 A CORP OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: INTERNATIONAL BUSINESS MACHINES CORPORATION
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • 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
    • B41J19/58—Differential or variable-spacing arrangements

Definitions

  • ABSTRACT A pair of stop surfaces carried by a dual pitch escapement rack selectively directly measure half space displacement of the escapement rack in accordance with its selected pitch setting. Motion for half space displacement is derived from a circumferentially symmetrical face cam couple that directly converts input rotary motion into output linear motion of the escapement rack.
  • the IBM SELECTRIC II typewriter as described in IBM Office Products Division Customer Engineering Service Manual Form No. 24l-56l5-l as reprinted February 1972, includes an escapement rack having two sets of teeth by which typing according to either of two pitches can be accomplished.
  • a half backspace control lever is provided to act through a series of bell cranks and levers to displace the escapement rack in the backspace direction by an amount equal to one-half the normal letter feed spacing.
  • the distance measurement for the backspace motion is accomplished by a pair of limit stops which provide a constant input motion to the rack driving bell crank.
  • a selective lost motion connection between the rack driving bell crank and the escapement rack itself converts the fixed input motion into either of the two half-space output motions required.
  • the half backspace device of our invention directly combines a V-shaped face cam, with a self-detenting pointed or V-shaped follower cam, both of which are mounted coaxially of the escapement rack to convert rotary motion from a control arm directly into linear motion of the escapement rack.
  • the face cam and follower cam provide symmetrical camming surfaces with respect to the axis of rack motion to obtain a smooth predictable linear movement of the escapement rack.
  • the stop member has two different stop portions which are longitudinally offset and angularly spaced from each other so as to be associated with the operative positions of the two sets of teeth, thereby alternately measuring the different size half backspace required for each pitch of the typewriter.
  • FIG. 1 is a perspective view of a dual pitch typewriter having a half backspace mechanism constructed in accordance with our invention.
  • FIG. 2 is a fragmentary perspective view of the half backspace mechanism showing the details of its construction.
  • FIG. 3 is an enlarged exploded view of a camming arrangement constructed in accordance with a preferred embodiment of our invention.
  • FIG. 1 shows a typewriter like that described in the aforesaid Service Manual, including a paper support platen 11 that cooperates with printing mechanism including a type element 12 to define a printing point 13 therebetween.
  • Type element 12 is mounted on a carrier 14 that is displaceable laterally along platen ll to move the printing point 13 along a writing line 15.
  • carrier 14 is laterally positioned by letter feeding mechanism including a pawl 16 thereon that engages an escapement rack 17.
  • Pawl 16 is arrested by a tooth of either a first series of teeth 18 on rack 17 that are spaced one-twelfth of an inch apart or alternatively, with a tooth of a second series of teeth 19 that are spaced one-tenth of an inch apart.
  • Control lever 20 is supported at one end of a sector link 21 that is pivoted on axis 21a and includes gear teeth 22 that engage complimentary teeth 23 in arbor 24 that is fixed to the escapement rack 17 by set screw 25.
  • a spring 26 is tensioned between extension 27 on arbor 24 and a tab 30 on bracket 31 that is supported by typewriter frame 32. The spring 26 urges a stop arm 28 into either the position shown, where it engages tab 30 or an alternate position where it engages a stationary frame mounted stud 33.
  • the mechanism thusfar described is substantially identical to that described in the aforementioned Service Manual.
  • the half backspace mechanism of our invention includes a stop member 40 that is attached by set screw 41 to the escapement rack 17. Stop member 40 in cludes two longitudinally offset, angularly displaced stop surfaces 42 and 43 which are respectively associated with the series of teeth 18 and 19.
  • Escapement rack 17 is slideably carried by a bore 34 in FIG. 3 in bracket 31 that guides rack movement along an axis 29 that is parallel to writing line 15.
  • a stud or abutment 35 carried by the frame mounted bracket 31 is spaced from selected leftward facing stop surface 42 by a distance 44 of one twenty-fourth of an inch, corresponding to one-half a one-twelfth inch tooth spacing of the teeth 18. A half backspace thus is measured simply by bringing the stop surface 42 into engagement with abutment 35.
  • a stationary cam member 45 is secured to bracket 31 by bolt 46 adjacent the rack 17.
  • Cam member 45 includes a V-shaped ramp camming surface 47 facing leftwardly along the rack axis 29.
  • a cooperating cam member 50 is rotatably carried on rack 17 adjacent cam member 45 and includes a relatively narrow, tooth or V-shaped cam follower portion 51 for engaging the sides of V-shaped camming surface 47. Both surface 47 ahd follower portion 51 extend symmetrically on diametrically opposite sides of the rack axis 29 thereby providing a pair of camming surface portions that balance the forces ap plied to cam member 50 and avoid undesired canting thereof.
  • Cam member 50 abuts arbor 24 to deliver longitudinal motion to the rack 17 in opposition to a spring 52.
  • Spring 52 is trapped by a clip 53 onto the rack 17 and abuts an offset bracket 54 carried by the bracket 31.
  • Spring 52 and arbor 24 thus effectively connect cam member 50 with the rack 17 for longitudinal movement therewith without interfering with rotary or transverse movement of cam member 50 therebetween.
  • the tooth shaped follower 51 is sufficiently narrow that it seeks the apex of V-shaped camming surface 47 under the urging of spring 52 to define a stable normal longitudinal position of rack 17 at the point of maximum penetration.
  • An extending arm 55 of the cam member 50 is connected through a clevis link 56 to control lever 57 having operator graspable handle 58 thereon.
  • Pivot connection 59 between clevis link 56 and control arm 57 is sufficiently loose to allow both pivoting and tilting action of the clevis link 56 which is required to accommodate both rotary and axial motion of the cam member 50.
  • control handle 58 To displace the printing point 13 by a half backspace, the operator grasps control handle 58 and moves it in the direction of arrow 60 toward the front of the typewriter 10. This motion lifts arm 55 of cam member 50 driving the pointed follower 51 thereof against the ramp camming surface 47 of stationary camming member 45. The resultant camming action drives cam member 50 against arbor 24 drawing rack 17 leftwardly in FIG. 2 until stop surface 42 engages abutment 35. Release of control handle 58 allows spring 52 to restore the parts to their original condition. When pitch selection control lever 20 is displaced to its alternate position, stop member 40 will present the alternate stop surface 43 into alignment with abutment 35.
  • Stop surface 43 is offset from stop surface 42 by one-one hundred twentieth of an inch which represents one-half the difference between ten and twelve pitch spacing.
  • the half backspace operation is identical to that described above with the exception that stop member 40 moves a slightly greater distance before stop surface 43 is arrested by engagement with abutment 35. In both cases, the operator feels a smooth consistent action at the control handle 58 which is terminated by a clear stop. Set up adjustment is accomplished simply by the use of a feeler guage for locating surface 42 the proper dis tance 44 from abutment 35 prior to tightening set screw 41.
  • a typewriter having printing and paper support means defining therebetween a printing point movable along a writing line, frame means, letter feeding mechanism comprising an escapement rack, means supporting said escapement rack on said frame means for movement along an axis that is parallel to said writing line, wherein the improvement comprises:
  • connecting means connecting said first camming member to said escapement rack for unitary move ment therewith in a first direction that is parallel to said writing line
  • one of said camming members being supported for movement relative to the other said camming member in a second direction that is transverse to said first direction
  • said first and second camming members each providing a plurality of camming surface portions that are symmetrically spaced about said axis of rack movement and are mutually configured such that rela tive movement therebetween in said second direction produces relative movement of said first camming member in said first direction.
  • control arm connected to said one of said camming members for moving said one of said camming members in said second direction
  • abutment means supportedly connected to said frame means in cooperatively spaced relationship with respect to said stop means whereby the motion of said escapement rack along said axis of rack movement is limited by engagement of said stop means with said abutment means.
  • said escapement rack comprises a cylindrical rod
  • said first camming member is rotatably carried by said cylindrical rod for rotational movement in said second direction and said second camming member is stationarily secured with respect to said frame means.

Landscapes

  • Character Spaces And Line Spaces In Printers (AREA)
  • Transmission Devices (AREA)
US418349A 1973-11-23 1973-11-23 Half backspace for dual pitch typewriter Expired - Lifetime US3893561A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US418349A US3893561A (en) 1973-11-23 1973-11-23 Half backspace for dual pitch typewriter
GB4033374A GB1436516A (en) 1973-11-23 1974-09-17 Typewriter
FR7434701A FR2252221B1 (enrdf_load_stackoverflow) 1973-11-23 1974-10-09
IT28317/74A IT1022789B (it) 1973-11-23 1974-10-11 Perfezionamento alle macchine per scrivere
JP11831274A JPS544289B2 (enrdf_load_stackoverflow) 1973-11-23 1974-10-16
CA211,472A CA1014504A (en) 1973-11-23 1974-10-16 Half backspace for dual pitch typewriter
CH1523974A CH575299A5 (enrdf_load_stackoverflow) 1973-11-23 1974-11-15
DE2455580A DE2455580C3 (de) 1973-11-23 1974-11-23 Teilschritt-Rückschalteinrichtung für Schreibmaschinen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US418349A US3893561A (en) 1973-11-23 1973-11-23 Half backspace for dual pitch typewriter

Publications (1)

Publication Number Publication Date
US3893561A true US3893561A (en) 1975-07-08

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ID=23657750

Family Applications (1)

Application Number Title Priority Date Filing Date
US418349A Expired - Lifetime US3893561A (en) 1973-11-23 1973-11-23 Half backspace for dual pitch typewriter

Country Status (8)

Country Link
US (1) US3893561A (enrdf_load_stackoverflow)
JP (1) JPS544289B2 (enrdf_load_stackoverflow)
CA (1) CA1014504A (enrdf_load_stackoverflow)
CH (1) CH575299A5 (enrdf_load_stackoverflow)
DE (1) DE2455580C3 (enrdf_load_stackoverflow)
FR (1) FR2252221B1 (enrdf_load_stackoverflow)
GB (1) GB1436516A (enrdf_load_stackoverflow)
IT (1) IT1022789B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4031994A (en) * 1975-12-24 1977-06-28 International Business Machines Corporation Double tab rack for a typewriter
US4322173A (en) * 1978-11-13 1982-03-30 Schacht Roy A Half-spacing feed mechanism for marking machine
US4383776A (en) * 1981-01-13 1983-05-17 Rozas Luis A V Typewriter with carriage escape bar adjustment
US4408918A (en) * 1981-05-01 1983-10-11 Scm Corporation Halfspace control system for electronic typewriter with correction register

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4229111A (en) * 1978-11-13 1980-10-21 Schacht Roy A Feed mechanism for marking machine
US4285605A (en) * 1979-07-02 1981-08-25 International Business Machines Corporation Escapement mechanism and backspace mechanism for a moving paper carriage typewriter having dual pitch capability

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1183056A (en) * 1916-02-16 1916-05-16 Edward M Wiley Type-writer half-spacing key.
US2065629A (en) * 1934-07-23 1936-12-29 Underwood Elliott Fisher Co Typewriting machine
US2162565A (en) * 1935-06-07 1939-06-13 Frank G Cain Line justification method and means for typewriting machines
US3346086A (en) * 1963-09-25 1967-10-10 Ibm Proportional escapement apparatus for a single element typewriter
US3366215A (en) * 1965-07-28 1968-01-30 Ibm Single rack backspace
US3540565A (en) * 1968-01-09 1970-11-17 Ibm Universal tab member
US3547245A (en) * 1968-01-09 1970-12-15 Ibm Multiple pitch margin control
US3578132A (en) * 1967-02-06 1971-05-11 Olivetti & Co Spa Half-space carriage return mechanism for typewriters
US3713524A (en) * 1970-06-30 1973-01-30 Ibm Bi directional spacing mechanism for a printer including a proportional spacing printer

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1183056A (en) * 1916-02-16 1916-05-16 Edward M Wiley Type-writer half-spacing key.
US2065629A (en) * 1934-07-23 1936-12-29 Underwood Elliott Fisher Co Typewriting machine
US2162565A (en) * 1935-06-07 1939-06-13 Frank G Cain Line justification method and means for typewriting machines
US3346086A (en) * 1963-09-25 1967-10-10 Ibm Proportional escapement apparatus for a single element typewriter
US3346087A (en) * 1963-09-25 1967-10-10 Ibm Pitch changing apparatus for proportional escapement typewriter
US3366215A (en) * 1965-07-28 1968-01-30 Ibm Single rack backspace
US3578132A (en) * 1967-02-06 1971-05-11 Olivetti & Co Spa Half-space carriage return mechanism for typewriters
US3540565A (en) * 1968-01-09 1970-11-17 Ibm Universal tab member
US3547245A (en) * 1968-01-09 1970-12-15 Ibm Multiple pitch margin control
US3713524A (en) * 1970-06-30 1973-01-30 Ibm Bi directional spacing mechanism for a printer including a proportional spacing printer

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4031994A (en) * 1975-12-24 1977-06-28 International Business Machines Corporation Double tab rack for a typewriter
US4322173A (en) * 1978-11-13 1982-03-30 Schacht Roy A Half-spacing feed mechanism for marking machine
US4383776A (en) * 1981-01-13 1983-05-17 Rozas Luis A V Typewriter with carriage escape bar adjustment
US4408918A (en) * 1981-05-01 1983-10-11 Scm Corporation Halfspace control system for electronic typewriter with correction register

Also Published As

Publication number Publication date
FR2252221A1 (enrdf_load_stackoverflow) 1975-06-20
FR2252221B1 (enrdf_load_stackoverflow) 1982-12-17
JPS5085415A (enrdf_load_stackoverflow) 1975-07-10
DE2455580C3 (de) 1980-08-21
JPS544289B2 (enrdf_load_stackoverflow) 1979-03-05
DE2455580A1 (de) 1975-05-28
DE2455580B2 (de) 1979-12-13
IT1022789B (it) 1978-04-20
CA1014504A (en) 1977-07-26
CH575299A5 (enrdf_load_stackoverflow) 1976-05-14
GB1436516A (en) 1976-05-19

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AS Assignment

Owner name: IBM INFORMATION PRODUCTS CORPORATION, 55 RAILROAD

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:INTERNATIONAL BUSINESS MACHINES CORPORATION;REEL/FRAME:005678/0098

Effective date: 19910326

Owner name: MORGAN BANK

Free format text: SECURITY INTEREST;ASSIGNOR:IBM INFORMATION PRODUCTS CORPORATION;REEL/FRAME:005678/0062

Effective date: 19910327