US3889794A - Typewriter platen releasing mechanism having an elastically deformable gear disc - Google Patents

Typewriter platen releasing mechanism having an elastically deformable gear disc Download PDF

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Publication number
US3889794A
US3889794A US419723A US41972373A US3889794A US 3889794 A US3889794 A US 3889794A US 419723 A US419723 A US 419723A US 41972373 A US41972373 A US 41972373A US 3889794 A US3889794 A US 3889794A
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US
United States
Prior art keywords
platen
gear
arbor
releasing mechanism
axially
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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
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US419723A
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English (en)
Inventor
Toshikatu Terashima
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NER KK
Nakajima All Co Ltd
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Nakajima All Co Ltd
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Publication of US3889794A publication Critical patent/US3889794A/en
Assigned to KABUSHIKI KAISHA N.E.R. reassignment KABUSHIKI KAISHA N.E.R. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: NAKAJIMA, NOBUYOSHI
Anticipated expiration legal-status Critical
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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
    • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
    • B41J11/24—Detents, brakes, or couplings for feed rollers or platens

Definitions

  • the spring disc may be caused to be elastically deformed into a dished form, away from the platen gear, for disconnecting the platen from the platen gear by means of a push button disposed in a recess of a platen knob through an interlocking member. This releases the engagement of the platen with the platen gear for free manual rotation of the former, irrespective of the engagement between the platen gear and a line changing mechanism of the typewriter. This allows relocating at a printing position a previously typewritten line of characters, which may require the correction or letter or a addition of a letter or a character.
  • the present invention relates in general to a typewriter, and particularly to a platen releasing mechanism of the typewriter. More particularly, this invention is concerned with a mechanism incorporated within the platen construction for releasing the engagement of the platen with a line changing mechanism, which is designed to release the engagement of the platen to enable the latter to be manually turned free from a preset rotating advancing motion of the platen, for the correction or addition of a previously typewritten letter or a character.
  • a device designed for releasing the platen from engagement with the line changing mechanism for manual angular rotation of the platen, free from a preset line changing or angular advancing motion by the line changing mechanism, thereby to enable the platen to be rotated by a desired angular advancing motion so as to accurately relocate the position of a line to be corrected or added with a letter or a charcter therein which was previously erroneously typewritten.
  • a platen or a platen shaft is provided with a connecting member which is designed to be axially slidable with respect to the platen or platen shaft by means of a slot or key construction incorporated therein, and which connecting member is further provided with gear serrations on the inner circumference thereof so that the connecting member may be engaged with gear serrations of the same tooth pitch, formed on the outer circumference of a piaten gear, which is intermittently driven by the line changing mechanism, for a stepwise rotating motion in accordance with a preset degree of rotation or, in other words, the desired line interval.
  • the platen Normally the platen is engaged with the line changing mechanism of the typewriter, and is intermittently rotated by the line changing mechanism through the abovementioned connecting member.
  • a button or the like provided in a platen knob, is pushed or pulled so as to cause the connecting member to slide axially with respect to the platen, there occurs a disengagement between the platen gear and the connecting member incorporated within the platen, whereby the platen is allowed to be rotated manually free from the line changing mechanism.
  • the platen releasing mechanism is of such construction that the connecting member, that engages the gear serrations provided on the platen gear as described above, is provided in an axially slidable manner with respect to the platen and the like by means ofa key and the like. Consequently, there might inevitably occur a relative play between the mutually engaging platen and the connecting member due to wear in the keyway or the like, thus resulting in a longitudinal deviation or staggering of a typewritten line of characters which should be properly aligned with a straight line. For preventing such an occurrence it is essential to finish the key or the keyway by high-precision machining, which results in high production costs.
  • This invention is particularly directed to cope with such drawbacks accompanying the conventional platen releasing mechanisms as described above.
  • FIG. 1 is a front view, partly in longitudinal section, showing a preferred, exemplary embodiment of the platen releasing mechanism according to this invention
  • FIG. 2 is a perspective view, partly cut away, showing a platen arbor used in the mechanism of this invention
  • FIG. 3 is a front veiw showing an example of a resilient disc, having a gear serration therearound', and
  • FIG. 4 is a front view of a modified example of the resilient disc, having a ring member fixed therearound.
  • FIG. 1 there is shown a conventional platen l of a typewriter, in fragmentary longitudinal section, and in the interior of one end of the platen l a boss 2 having a cylindrical sleeve 2a is press fitted.
  • a sleeve-like extension 30 of a platen gear 3 to be driven by a conventional line changing mechanism of the typewriter in such a manner that it may rotate in and along the inner circumference of the sleeve 2a.
  • a projection 2b will be described somewhat later.
  • a ratchet wheel 3a for driven engagement with a driving pawl (not shown) of the line changing mechanism, while there is formed an opening (preferably, a frustoconical opening) in the free or inner end of the sleevelike extension 3c, as shown in FIG. 1.
  • Inner gear serrations 3b are formed on the inner frusto-conical surface of the opening.
  • a platen arbor 5 is threadedly fitted at the right end thereof as viewed in FIG. 1, the platen arbor 5 having a knob 4 at the opposite or left end thereof. Projections 4a will be described further down. More specifically, the platen arbor 5 comprises an extension 6 ofa smaller diameter having screw-threads 6a thereon for threaded engagement with the boss 2, and a barrel portion 7 of a larger diameter extending outwardly from the platen 1 when installed, and there is formed a shoulder 7a between the extension 6 and the barrel portion 7.
  • the barrel portion 7 is provided therein with a bore 7b extending in the axial direction thereof and opening outwardly therefrom, and is further provided with a plurality of, for instance, two radial slots 7c originating from the shoulder 70 and extending in the axial direction to join with the abovementioned bore 719.
  • the screw threads 60 are left-hand threads so that they are prevented from being loosened due to the rotation of the platen 1 during typographical operations.
  • a resilient disc 8 On the extension 6 of the platen arbor 5, there is disposed a resilient disc 8, as shown in FIG. 3, which is made of elastic metal, for example, and has outer gear serrations 8a on the outer circumference thereof for meshing engagement with the inner gear serrations 3b on the frustoconical surface of the platen gear 3, the resilient disc 8 being rigidly clamped between the shoulder 7a and the earlienmentioned annular projection 2b, formed on the central portion of the boss 2, so that the resilient disc 8 may not be loosened relative to the boss 2 and hence the platen 1 during the operation.
  • a cylindrical sleeve member 9 on the outer circumference of the barrel portion 7 of the platen arbor 5, the inner end portion thereof facing the platen l and having an enlarged diameter which is in contact with the outer marginal portion of the resilient disc 8.
  • a core member 11 under the bias of a resilient member such as a compression coil spring 10.
  • the inner end of the member 11 abuts the abovementioned arms 90, while the outer end of the member 11 is provided with a push button 12.
  • the latter is set in position in a recess of the platen knob 4 in such a manner that a flanged portion 12a formed on the outer circumference of the push button 12 abuttingly engages the earlier mentioned, radially inwardly extending projections 4a on the platen knob 4, whereby the core member 11 is prevented from axially outwardly moving beyond the position shown in FIG. 1 under the bias of the spring 10. Parts 18, 18a, 18b will be described later in connec tion with FIG. 4.
  • the platen l and the platen gear 3 may now be caused to work as an integral unit through the resilient disc 8 and the boss 2, the platen 1 being thus driven in rotation by the line changing mechanism (not shown) of the typewriter in accordance with a preset extent of rotation or anguglar advancing motion in terms of a given pitch of the ratchet wheel 3a on the platen gear 3.
  • the cylindrical sleeve member 9 is caused to travel axially inwardly along the platen arbor 5, toward the right as viewed in FIG. I, with the inner end (the rightmost part in FIG. 1) of the member 11 abutting the arms 9a of the member 9.
  • the peripheral portion of the resilient disc 8 is caused to be deformed or warped elastically away from the serrations 3b in the inward direction of the platen 1, thereby disengaging the serrations 8a from the serrations 3b and thus permitting the platen l and the platen gear 3 to be disconnected from each other for free manual rotation.
  • the resilient disc 8 may be of a construction comprising a single resilient disc 18 and a ring member 18b secured to the disc 18 and having outer gear serrations 18a as illustrated in FIG. 4.
  • a unique and useful platen releasing mechanism which features the following advantages over conventional mechanisms.
  • the spring disc having resilience in the axial direction of the platen, while having rigidity in the rotating direction of the platen over the entire circumference thereof, used for the engagement between the platen and the platen gear, there is no need for the provision of any key construction in the power transmitting portion between the two members as in conventional mechanisms, which would inevitably result in high production costs.
  • the platen releasing mechanism according to this invention features a simple yet reliable and durable construction, which in turn enables the production as well as the maintenance costs to be cut substantially.
  • a releasing mechanism for a cylindrical platen of a typewriter the typewriter further including a line changing mechanism, the releasing mechanism comprising, in combination: a boss secured in the interior of said platen at one end thereof; a platen gear rotatably and coaxially inserted in said boss and having means forming an opening with inner, first gear serrations at the axially inner end thereof, and a ratchet wheel on the outer circumference and at the axially 0pposite end thereof, for driven engagement with said line changing mechanism; a platen arbor having the axially inner end rigidly secured to a central portion of said boss.
  • a platen knob secured to the outer end of said arbor; a resilient. disc-shaped member rigidly mounted on said arbor and having second gear serrations on the outer circumferencc thereof for meshing engagement with said first gear serrations; a sleeve member mounted on said arbor. slidable in the axial direction of said arbor nonrotatable relative to said arbort and abutting a radially outer portion of said resilient member; and operating means axially slidably mounted in said arbor. having one end thereof in contact with said sleeve member.
  • the platen releasing mechanism as defined in claim 4. further comprising a spring disposed in said arbor and resiliently urging said core member in an axially outward direction, and further comprising means for limiting the axial outward movement of said core member.

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US419723A 1973-04-02 1973-11-28 Typewriter platen releasing mechanism having an elastically deformable gear disc Expired - Lifetime US3889794A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1973038727U JPS49138905U (enrdf_load_stackoverflow) 1973-04-02 1973-04-02

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US3889794A true US3889794A (en) 1975-06-17

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JP (1) JPS49138905U (enrdf_load_stackoverflow)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US661628A (en) * 1897-11-03 1900-11-13 Yost Writing Machine Co Type-writing machine.
US965421A (en) * 1909-08-04 1910-07-26 Underwood Typewriter Co Type-writing machine.
US1749835A (en) * 1927-10-10 1930-03-11 Royal Typewriter Co Inc Typewriting machine

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4520962Y1 (enrdf_load_stackoverflow) * 1965-03-15 1970-08-21

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US661628A (en) * 1897-11-03 1900-11-13 Yost Writing Machine Co Type-writing machine.
US965421A (en) * 1909-08-04 1910-07-26 Underwood Typewriter Co Type-writing machine.
US1749835A (en) * 1927-10-10 1930-03-11 Royal Typewriter Co Inc Typewriting machine

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Publication number Publication date
JPS49138905U (enrdf_load_stackoverflow) 1974-11-29

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Date Code Title Description
AS Assignment

Owner name: KABUSHIKI KAISHA N.E.R. 25-7, HAKOZAKI-CHO, NIHONB

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:NAKAJIMA, NOBUYOSHI;REEL/FRAME:003849/0285

Effective date: 19810330