US3670647A - Method of damping rebound of print hammer - Google Patents

Method of damping rebound of print hammer Download PDF

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Publication number
US3670647A
US3670647A US878313A US3670647DA US3670647A US 3670647 A US3670647 A US 3670647A US 878313 A US878313 A US 878313A US 3670647D A US3670647D A US 3670647DA US 3670647 A US3670647 A US 3670647A
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US
United States
Prior art keywords
hammer
armature
rebound
print
relay
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
US878313A
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English (en)
Inventor
John W Funk
Kishor M Lakhani
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Unisys Corp
Original Assignee
Burroughs 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 Burroughs Corp filed Critical Burroughs Corp
Application granted granted Critical
Publication of US3670647A publication Critical patent/US3670647A/en
Assigned to BURROUGHS CORPORATION reassignment BURROUGHS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). DELAWARE EFFECTIVE MAY 30, 1982. Assignors: BURROUGHS CORPORATION A CORP OF MI (MERGED INTO), BURROUGHS DELAWARE INCORPORATED A DE CORP. (CHANGED TO)
Assigned to UNISYS CORPORATION reassignment UNISYS CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). Assignors: BURROUGHS 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
    • B41J9/00—Hammer-impression mechanisms
    • B41J9/26—Means for operating hammers to effect impression
    • B41J9/38—Electromagnetic means
    • 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
    • B41J9/00—Hammer-impression mechanisms
    • B41J9/42—Hammer-impression mechanisms with anti-rebound arrangements

Definitions

  • the armature of the relay is pivotably mounted and imparts motion to the hammer.
  • the CL /426, 101/93 C, 197/49 solenoid of the relay physically restrains the motion of the ar- 1] Int. Cl. .B41j 9/ ,1 mature and then holds the annature by residual magnetism.
  • Fkld O'SQII'C'I ..l0l/93,426; 197/49 The hammer continues in ine tial flight until it reaches the printing area.
  • This invention relates to printing and, more particularly, to a high speed electromagnetically operated print hammer and associated components, with particular reference to damping the hammer oscillations.
  • electromagnetic actuator mechanisms are well known.
  • the solenoid is stationary and, when current is introduced into the coil of the solenoid, the hammer is attracted thereto. This is seen, for example, in US Pat. No. 3,335,659 to Schacht et al.
  • a second method of damping oscillations includes the use of a backstop and a second electromagnet.
  • this method has proven uneconomical since it requires additional hardware as well as substantially doubling the current requirements of the actuator apparatus.
  • the invention contemplates the solution of these problems by providing a new and improved method of damping the rebound of the print hammer to eliminate multiple impressions.
  • an inertial print hammer and actuator module wherein a print hammer is driven into the print area by the armature of a magnetic core electromagnetic relay and rebounds toward its rest position.
  • the relay is momentarily energized for attracting the armature and actuating the hammer, the armature is held in the path of the rebounding hammer by residual magnetism, and part of the kinetic energy of the hammer is absorbed by impacting the hammer against the armature and breaking the armature free from the magnetic field.
  • the hammer follows the armature and the balance of the energy of thehammer is dissipated through the armature by a resilient backstop for the armature.
  • the effect of the method is increased by resiliently biasing the hammer against the armature, and the actuated position of the armature may be spaced away from the magnetic core for preventing magnetic lock.
  • a "print hammer drives the paper or other recording medium 11 and the inking element or ribbon 13 into the type face 15 on revolving drum or chain 17. This occurs at the print station or printing area 19 and is well known in the high speed printing art whether the printer utilizes a single hammer, which moves along the line of print from one print position to the next, or multiple hammers one at each of the print positions.
  • the invention will be described with reference to a print hammer module which may be used with either type of printer.
  • the particular logic circuitry which controls the time that the actuator fires the hammer and the structure that relatively positions the hammer module and the drum are also well known and do not form a part of the present invention.
  • the print hammer module 21 comprises base 23, lightweight print hammer or interposer 25, actuator or armature 27, backstop 29, and additional hardware which will be more fully described hereinafter.
  • Armature 27 is pivotably mounted at its lower end to the base 23.
  • springs 33 normally bias the actuator away from the printing area 19 and towards its rest position in contact with backstop 29.
  • Means are provided to overcome the biasing effect of springs 33 and impart motion to hammer 25.
  • Solenoid 35 includes a coil which is wound in series on two individual bobbins 37. The bobbins and coil may be encapsulated for heat dissipation. The wound bobbins are force fit onto pole pieces 36 which are attached to (or, alternatively, projections of) base 23.
  • actuator 27 When current is introduced into the coil the resultant magnetic field attracts the actuator 27 to the solenoid 35.
  • actuator 27 serves as an armature and alongwith the solenoid forms an electromagnetic relay. Since the armature is pivoted about one end (at pivot 31) the armature travels in a clockwise direction towards the print area 19 when current flows in the coil.
  • Hammer 25 is flexurally mounted on the upper portion of the base 23. Although the hammer is a single unit it may be thought of as having an imprint end 39, which presses the paper and ribbon against the type face, and an acceleration end 41 which isdriven by the actuator.
  • the interposer or hammer 25, for convenience, is attached to the base 23 by two leaf springs 43 and is biased rearwardlly, away from the print area 19, into contact with armature 27..
  • the leaf springs are attached to the base and hammer by injection molding plastic into anchor holes 45. I
  • the backstop 29 Mounted at the left side of the base 23, at a position opposite that of the print area 19 and below the level of the interposer or hammer 25, is backstop 29.
  • the backstop includes a bumper 47 made of a resilient shock absorbing material, such as those in the butyl rubber family, and covered with a steel cap.
  • the bumper 47 is mounted on one end of shaft 49.
  • the other end of shaft 49 is threaded and inserted into a suitable opening in base 23. Since the actuator is struck at one end by the returning hammer 25 and pivoted at the other end 31 it will be appreciated that on rebound there is both shear force and compressional force on the backstop 29.
  • the butyl rubber backstop provides better damping of shear loading, hence a design consideration is to increase the ratio of shear to compressional loading. Although the overall geometry of the print hammer and actuator creates certain limits on this ratio, the higher this ratio the smaller mass backstop necessary.
  • a socket head cap screw including head 51 and shank or shaft portion 49 may be turned thereby moving the backstop 29 toward or away from the print area 19.
  • the backstop 29 may be joined to the shank 49 by an epoxy resin. Adjustment of the backstop location causes a corresponding change in the rest position of armature 27 thereby increasing or decreasing the width of the air gap from armature 27 to the solenoid 35. Changes in the air gap width result in corresponding changes in the travel time of the armature 27 when current is introduced into the coil.
  • Current in the coil is turned off about the time the actuator comes into contact with the solenoid 35.
  • the precise time is not critical, to minimize both use of current and the amount of heat generated, the current should be turned off after the actuator has been attracted by a sufficient. electromagnetic force that it will drive the hammer into the print area yet before the hammer reaches the actuator on rebound.
  • the hammer 25 continues to travel under its own inertia into the print area to provide the printing operation as explained previously.
  • the current in the coil of the solenoid 35 has been turned off, the actuator is maintained in contact with the solenoid 35 by the residual magnetic flux. This defines the second electromagnetic condition.
  • Well known circuitry is available for supplying appropriate current, such as a pulse, to the coil.
  • the hammer After the imprint end 39 of the hammer strikes the print area, the hammer rebounds from the impact as is understood from the principles of conservation of energy and momentum. As the hammer rebounds, end 41 impacts the striking face 53 of the actuator. Under the influence of the returning hammer the actuator breaks through the residual magnetism of solenoid 35 and starts rotating in a counterclockwise direction away from the print area and towards the backstop 29. This uses up some of the kinetic energy of the light-weight hammer 25. The continued lateral motion of the hammer 25 and the counterclockwise motion of armature 27 are ultimately stopped by the resilient backstop 29.
  • the resilient backstop 29, which is struck by the rear portion 55 of actuator 27 dissipates the remaining kinetic energy of the hammer and all the kinetic energy of the returning actuator.
  • the leaf springs 43 urge the hammer 25 toward its rest position in contact with the armature 27
  • a hammer made of hardened steel and having a mass of 1.5 X lb-in"-sec. gravitational system and a backstop of buna-n(a butyl rubber)
  • the absorption of the kinetic energy of the hammer by both breaking free from the residual magnetism of the solenoid and by contact with the backstop, provides a damping efiect. This reduces hammer oscillations and prevents a second rebound of the hammer into the print area. Furthermore, the absorption of part of the kinetic energy when the hammer breaks the armature free from the residual magnetic field permits the use of a smaller backstop 29, and, by early damping, permits higher frequency of operation.
  • step of resiliently damping the balance of the kinetic energy of the rebounding hammer includes the step of distorting a butyl rubber member in both shear and compression.
  • the method of claim 2 also including after the step of energizing the step of spacing the energized position of said armature away from said core for preventing said armature from magnetically locking with said core.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Impact Printers (AREA)
US878313A 1969-11-20 1969-11-20 Method of damping rebound of print hammer Expired - Lifetime US3670647A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US87831369A 1969-11-20 1969-11-20

Publications (1)

Publication Number Publication Date
US3670647A true US3670647A (en) 1972-06-20

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ID=25371778

Family Applications (1)

Application Number Title Priority Date Filing Date
US878313A Expired - Lifetime US3670647A (en) 1969-11-20 1969-11-20 Method of damping rebound of print hammer

Country Status (7)

Country Link
US (1) US3670647A (enrdf_load_stackoverflow)
BE (1) BE758496A (enrdf_load_stackoverflow)
CH (1) CH527698A (enrdf_load_stackoverflow)
DE (1) DE2054499A1 (enrdf_load_stackoverflow)
FR (1) FR2066731A5 (enrdf_load_stackoverflow)
GB (1) GB1265935A (enrdf_load_stackoverflow)
NL (1) NL7016342A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3747522A (en) * 1970-10-20 1973-07-24 Honeywell Bull Soc Ind Endless type carrier with type fingers connected by an endless strip and interposed viscous damping blocks
US3776131A (en) * 1971-08-31 1973-12-04 Tokyo Shibaura Electric Co Printer
US3793947A (en) * 1972-04-13 1974-02-26 Addressograph Multigraph Sequential hammer imprinter
US3834305A (en) * 1972-08-23 1974-09-10 Suwa Seikosha Kk Printer
US3968744A (en) * 1975-03-03 1976-07-13 Burroughs Corporation Self-damping unitary print hammer for high speed printers
US3981236A (en) * 1974-03-11 1976-09-21 Sperry Rand Corporation Printhead for impact printer
US3994218A (en) * 1974-12-18 1976-11-30 Teletype Corporation Energy absorbing print hammer bumper with internal stabilizer
US4306817A (en) * 1979-11-05 1981-12-22 International Telephone And Telegraph Corporation Bar code printing mechanism
US4324497A (en) * 1979-11-05 1982-04-13 Xerox Corporation Print hammer assembly with amplified multi-location impacts
US4327639A (en) * 1979-11-05 1982-05-04 Xerox Corporation Print hammer assembly with multi-location impacts
US4389127A (en) * 1979-12-10 1983-06-21 Florida Data Corporation High speed dot matrix impact printer
US4395945A (en) * 1979-08-13 1983-08-02 Dataproducts Corporation Hammer bank assembly
US4557192A (en) * 1981-05-26 1985-12-10 International Business Machines Corporation Self restoring pivoting means and print hammer using same
EP0216611A1 (en) * 1985-09-20 1987-04-01 International Business Machines Corporation Print hammer actuator for impact printer
US20050257594A1 (en) * 2004-05-21 2005-11-24 Larry Hutchison Graphic arts die and support plate assembly

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2191476A5 (enrdf_load_stackoverflow) * 1972-06-28 1974-02-01 Honeywell Bull
DE2702483C2 (de) * 1977-01-21 1982-06-03 Siemens AG, 1000 Berlin und 8000 München Anordnung für Druckeinrichtungen, wie Schreibmaschinen u.dgl., zum geräuscharmen und stoßarmen Abfangen von bewegten Teilen
US4603985A (en) * 1984-06-21 1986-08-05 International Business Machines Corporation Backstop and damping apparatus for actuator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787210A (en) * 1953-01-22 1957-04-02 Jr Francis H Shepard Hammer impelling means in high speed printers
US3195453A (en) * 1962-12-26 1965-07-20 Potter Instrument Co Inc Magnetically actuated print hammer
US3266419A (en) * 1964-08-11 1966-08-16 Navigation Computer Corp High speed impact print hammer assembly with resilient energy storing means
US3266418A (en) * 1963-12-02 1966-08-16 Anelex Corp Print hammer assembly for high speed printers
US3426675A (en) * 1967-03-17 1969-02-11 Mohawk Data Sciences Corp Print hammer module
US3447455A (en) * 1967-09-20 1969-06-03 Honeywell Inc Print-hammer mount and fabrication method
US3507213A (en) * 1966-10-14 1970-04-21 English Electric Computers Ltd High speed flying hammer solenoid systems

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2787210A (en) * 1953-01-22 1957-04-02 Jr Francis H Shepard Hammer impelling means in high speed printers
US3195453A (en) * 1962-12-26 1965-07-20 Potter Instrument Co Inc Magnetically actuated print hammer
US3266418A (en) * 1963-12-02 1966-08-16 Anelex Corp Print hammer assembly for high speed printers
US3266419A (en) * 1964-08-11 1966-08-16 Navigation Computer Corp High speed impact print hammer assembly with resilient energy storing means
US3507213A (en) * 1966-10-14 1970-04-21 English Electric Computers Ltd High speed flying hammer solenoid systems
US3426675A (en) * 1967-03-17 1969-02-11 Mohawk Data Sciences Corp Print hammer module
US3447455A (en) * 1967-09-20 1969-06-03 Honeywell Inc Print-hammer mount and fabrication method

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3747522A (en) * 1970-10-20 1973-07-24 Honeywell Bull Soc Ind Endless type carrier with type fingers connected by an endless strip and interposed viscous damping blocks
US3776131A (en) * 1971-08-31 1973-12-04 Tokyo Shibaura Electric Co Printer
US3793947A (en) * 1972-04-13 1974-02-26 Addressograph Multigraph Sequential hammer imprinter
US3834305A (en) * 1972-08-23 1974-09-10 Suwa Seikosha Kk Printer
US3981236A (en) * 1974-03-11 1976-09-21 Sperry Rand Corporation Printhead for impact printer
US3994218A (en) * 1974-12-18 1976-11-30 Teletype Corporation Energy absorbing print hammer bumper with internal stabilizer
US3968744A (en) * 1975-03-03 1976-07-13 Burroughs Corporation Self-damping unitary print hammer for high speed printers
US4395945A (en) * 1979-08-13 1983-08-02 Dataproducts Corporation Hammer bank assembly
US4324497A (en) * 1979-11-05 1982-04-13 Xerox Corporation Print hammer assembly with amplified multi-location impacts
US4327639A (en) * 1979-11-05 1982-05-04 Xerox Corporation Print hammer assembly with multi-location impacts
US4306817A (en) * 1979-11-05 1981-12-22 International Telephone And Telegraph Corporation Bar code printing mechanism
US4389127A (en) * 1979-12-10 1983-06-21 Florida Data Corporation High speed dot matrix impact printer
US4557192A (en) * 1981-05-26 1985-12-10 International Business Machines Corporation Self restoring pivoting means and print hammer using same
EP0216611A1 (en) * 1985-09-20 1987-04-01 International Business Machines Corporation Print hammer actuator for impact printer
US20050257594A1 (en) * 2004-05-21 2005-11-24 Larry Hutchison Graphic arts die and support plate assembly
US7096709B2 (en) 2004-05-21 2006-08-29 Universal Engraving, Inc. Graphic arts die and support plate assembly

Also Published As

Publication number Publication date
NL7016342A (enrdf_load_stackoverflow) 1971-05-24
CH527698A (de) 1972-09-15
DE2054499A1 (de) 1971-05-27
BE758496A (fr) 1971-04-16
GB1265935A (enrdf_load_stackoverflow) 1972-03-08
FR2066731A5 (enrdf_load_stackoverflow) 1971-08-06

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AS Assignment

Owner name: BURROUGHS CORPORATION

Free format text: MERGER;ASSIGNORS:BURROUGHS CORPORATION A CORP OF MI (MERGED INTO);BURROUGHS DELAWARE INCORPORATEDA DE CORP. (CHANGED TO);REEL/FRAME:004312/0324

Effective date: 19840530

AS Assignment

Owner name: UNISYS CORPORATION, PENNSYLVANIA

Free format text: MERGER;ASSIGNOR:BURROUGHS CORPORATION;REEL/FRAME:005012/0501

Effective date: 19880509