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EP0406957A2 - Elektromagnetisch angetriebener Druckhammer - Google Patents

Elektromagnetisch angetriebener Druckhammer Download PDF

Info

Publication number
EP0406957A2
EP0406957A2 EP90201737A EP90201737A EP0406957A2 EP 0406957 A2 EP0406957 A2 EP 0406957A2 EP 90201737 A EP90201737 A EP 90201737A EP 90201737 A EP90201737 A EP 90201737A EP 0406957 A2 EP0406957 A2 EP 0406957A2
Authority
EP
European Patent Office
Prior art keywords
plunger
coil
solenoid
permanent magnet
walls
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.)
Withdrawn
Application number
EP90201737A
Other languages
English (en)
French (fr)
Other versions
EP0406957A3 (en
Inventor
Ping-Shih Wang
Chwee Peng Ang
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.)
Philips North America LLC
US Philips Corp
Original Assignee
US Philips Corp
North American Philips 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 US Philips Corp, North American Philips Corp filed Critical US Philips Corp
Publication of EP0406957A2 publication Critical patent/EP0406957A2/de
Publication of EP0406957A3 publication Critical patent/EP0406957A3/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/16—Rectilinearly-movable armatures
    • H01F7/1607—Armatures entering the winding
    • H01F7/1615—Armatures or stationary parts of magnetic circuit having permanent magnet
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/16—Rectilinearly-movable armatures
    • H01F7/1607—Armatures entering the winding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
    • H01F7/122—Guiding or setting position of armatures, e.g. retaining armatures in their end position by permanent magnets

Definitions

  • the invention relates to electromagnetic actuators. More specifically, the invention relates to a solenoid actuator which is particularly suited for hammering type bars in an impact printer.
  • Electromagnetic solenoids are used in many impact printers to drive type bars and printing pins.
  • a printer solenoid actuator should exert relatively high mechanical force to produce clear print impressions and should have low inertia to enable high printing rates.
  • the actuator mechanism should be mechanically damped to avoid bounce and vibration which can distort printed characters and produce multiple images.
  • Japanese Patent 61 194802 to Shindengen apparently describes a hammer solenoid which is specially adapted to reduce impact bounce and vibration.
  • the solenoid plunger comprises a hollow cylinder with a truncated recess at its rear end.
  • a steel ball floats in the recess, between the rear end of the plunger and the back of the solenoid housing, and functions to dampen vibration and rebound when a hammer of the plunger strikes the anvil of a type bar.
  • the steel ball is, however, relatively insignificant in terms of the magnetic mass of the plunger and does not significantly affect its magnet properties.
  • the plunger of a printer hammer solenoid is constructed as a hollow ferromagnetic cylinder.
  • a slug of ferromagnetic material attached to the rear end of the plunger as a flux booster significantly shifts the magnetic center mass of the plunger to enhance the force supplied by a solenoid coil.
  • the hollow plunger structure is relatively "dead” to reduce hammer bounce and vibration.
  • the walls of the hollow cylinder are sufficiently thinned so that they magnetically saturate when the coil is actuated. This further shifts the magnetic mass of the plunger to the rear and enhances the impact force.
  • the ferromagnetic slug comprises a permanent magnet which is attracted by the field of the solenoid coil.
  • the invention can be understood with reference to the attached drawing which is a sectional view of a printer hammer solenoid with the hammer extended through one halt ot its total travel.
  • a hollow coil 10 is contained within a cylindrical ferromagnetic housing which includes a front housing half 20 and rear housing half 30.
  • a hollow, cylindrical ferromagnetic plunger 40 is contained within coil 10 and flux return ring 50.
  • a hammer actuator 70 is attached to the front end of the plunger 40 and slidably supported by bushing 60.
  • the front end of the hammer actuator 70 is provided with a surface 80 which is adapted to impact an anvil of a type bar, for example on a printer daisy wheel.
  • a spring 90 disposed between the front end of the plunger 40 and the housing 20, rearwardly urges the plunger so that its magnetic center of mass is remote from the center of the coil 10 when the coil is in an unactuated state.
  • Plastic and rubber damping members 100, 110 are disposed in the rear end of the housing 30 to cushion the impact of the plunger when it returns to its rest condition.
  • a slug of ferromagnetic material 120 is disposed within the rear end of the hollow plunger 40. The slug 120, which may be press fit or adhesively bonded to the plunger, acts as a flux booster to rearwardly shift the magnetic center of the plunger which increases the force and travel of the plunger when the coil is actuated.
  • the side walls 130 are sufficiently thinned so that they magnetically saturate when the coil is energized at its desired working current, for example, by current source 140.
  • the magnetic center of the plunger is thus further shifted to the rear to enhance the operating force and travel.
  • the side walls are permanently magnetized and are polarized so that the permanent magnetic field attracts the magnetic field of the energized coil, thus further enhancing the force and travel of the plunger.
  • the flux produced in the plunger walls 130 by the permanent magnet is sufficient to magnetically saturate the walls.
  • the solenoid of the invention provides a relatively vibration and bounce free printing hammer which has high impact force and travel and is well suited for use in printing applications.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Impact Printers (AREA)
  • Electromagnets (AREA)
EP19900201737 1989-07-05 1990-06-29 Hammer solenoid Withdrawn EP0406957A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37606889A 1989-07-05 1989-07-05
US376068 2003-02-26

Publications (2)

Publication Number Publication Date
EP0406957A2 true EP0406957A2 (de) 1991-01-09
EP0406957A3 EP0406957A3 (en) 1991-04-03

Family

ID=23483575

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900201737 Withdrawn EP0406957A3 (en) 1989-07-05 1990-06-29 Hammer solenoid

Country Status (3)

Country Link
EP (1) EP0406957A3 (de)
JP (1) JPH0395902A (de)
CA (1) CA2020211A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0794540A1 (de) * 1996-03-08 1997-09-10 Harting KGaA Bistabiler Kleinmagnet
GB2304163B (en) * 1995-08-05 1999-03-17 Uponor Ltd Pipe joint and electrofusion coupling therefor

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961298A (en) * 1975-05-07 1976-06-01 The Singer Company Dual plunger solenoid
DE2605538A1 (de) * 1975-10-31 1977-05-12 Hermes Precisa International Vorrichtung zur betaetigung einer nadel in einem drahtdruckerkopf
US4125336A (en) * 1976-04-08 1978-11-14 Wang Laboratories, Inc. Dot matrix printer
US4468142A (en) * 1982-11-12 1984-08-28 Genicom Corporation Pint wire actuator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961298A (en) * 1975-05-07 1976-06-01 The Singer Company Dual plunger solenoid
DE2605538A1 (de) * 1975-10-31 1977-05-12 Hermes Precisa International Vorrichtung zur betaetigung einer nadel in einem drahtdruckerkopf
US4125336A (en) * 1976-04-08 1978-11-14 Wang Laboratories, Inc. Dot matrix printer
US4468142A (en) * 1982-11-12 1984-08-28 Genicom Corporation Pint wire actuator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2304163B (en) * 1995-08-05 1999-03-17 Uponor Ltd Pipe joint and electrofusion coupling therefor
EP0794540A1 (de) * 1996-03-08 1997-09-10 Harting KGaA Bistabiler Kleinmagnet

Also Published As

Publication number Publication date
JPH0395902A (ja) 1991-04-22
EP0406957A3 (en) 1991-04-03
CA2020211A1 (en) 1991-01-06

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