EP0019706A1 - Print element actuator for a wire printer - Google Patents

Print element actuator for a wire printer Download PDF

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Publication number
EP0019706A1
EP0019706A1 EP80101919A EP80101919A EP0019706A1 EP 0019706 A1 EP0019706 A1 EP 0019706A1 EP 80101919 A EP80101919 A EP 80101919A EP 80101919 A EP80101919 A EP 80101919A EP 0019706 A1 EP0019706 A1 EP 0019706A1
Authority
EP
European Patent Office
Prior art keywords
electromagnet
armature
permanent magnet
magnet
magnetic
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.)
Granted
Application number
EP80101919A
Other languages
German (de)
French (fr)
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EP0019706B1 (en
Inventor
Robert Wayne Kulterman
Joseph Edmund Linsinski
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International Business Machines Corp
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International Business Machines Corp
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Publication date
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Publication of EP0019706A1 publication Critical patent/EP0019706A1/en
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Publication of EP0019706B1 publication Critical patent/EP0019706B1/en
Expired legal-status Critical Current

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    • 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
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/22—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material
    • B41J2/23—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of impact or pressure on a printing material or impression-transfer material using print wires
    • B41J2/27—Actuators for print wires
    • B41J2/285—Actuators for print wires of plunger type
    • 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 present invention relates to a print wire control device for a wire matrix printer and more particularly, a type of control device in which no spring contributes to the forward or backward movement of the print wire.
  • Wire matrix printers are well known in the prior art.
  • the printers include a set of thin wires arranged in a vertical column. Each wire can be actuated to be driven forward against a ribbon and a printing medium, such as paper, disposed around the platen of the printer. When the thread is drawn forward and comes into contact with the ribbon, a point appears on the paper.
  • the control of one or more of the threads during their lateral movement on the paper can be used to cause the printing of characters, in a manner known in the prior art.
  • wire matrix is described in patent No. 74 39730 filed in France by the plaintiff on October 16, 1974 and a control means of this printer is described in patent No. 77 33124 filed in France by the plaintiff on October 27, 1977.
  • the devices controlling the movement of the wires forwards consist of an electromagnet to which an electrical signal is applied to create a magnetic field which drives a frame towards the front.
  • the frame is connected to the print wire and when it moves forward, it drives the print wire.
  • the reinforcement After striking the ribbon which causes the dot to be printed on the paper, the reinforcement is returned to its initial or rest position by a spring.
  • a print head using in combination an electromagnet and a spring to control the movement of the print wire is described in patent No. 71 32174 filed in France by the applicant on June 26, 1971 in US-A-4,046 244.
  • Wire control devices using a spring have two drawbacks. The first is that the spring tends to wear out and can therefore be subject to mechanical failure. The second is that the spring applies forces opposing the movement of the wire when the latter is driven forward to strike the ribbon so that, when the wire strikes the ribbon, the force exerted in the opposite direction by the spring is maximum. Thus, a greater supply must be applied to the electromagnet to cause the wire to be drawn forward with sufficient force ensuring that a good quality printed point is obtained.
  • US-A-3,946,851 discloses a device in which a permanent magnet controls the return of the printing wire after its movement forward.
  • US-A-3,775,714 discloses a device in which the armature itself is a permanent magnet which controls its own removal after being moved forward. This device has a certain number of drawbacks in that the armature being a permanent magnet, it has low magnetic conduction.
  • US-A-3,755,766 discloses a device in which the permanent magnet is used to hold a frame against a rear stop and in which the electromagnet must be excited with a determined polarity to drive the frame forward and with a polarity opposite to drag it backwards.
  • This control device further comprises a first magnetic circuit comprising the electromagnet and the armature which are traversed by a flux, when the electromagnet is excited, for controlling the forward movement of the printing wire, and a second magnetic circuit comprising the armature and the permanent magnet, which, when the electromagnet is not energized, are traversed by a flux for controlling the backward movement of the printing wire.
  • This device if it offers a clear improvement compared to the previous devices, however presents certain drawbacks in particular of relatively large reluctances in the magnetic circuits, which obliges to use a strong supply to control the electromagnet.
  • the action exerted by the permanent magnet is not constant during the displacement of the printing wire.
  • the present invention overcomes these drawbacks thanks to a printing wire control device of the kind comprising two separate magnetic circuits for moving the printing wire respectively forwards and backwards, this device comprising a ring made of magnetic material. located against the electromagnet and defining a magnetic circuit with the electromagnet and the armature.
  • the present invention also relates to a device for controlling printing threads in which the magnetic forces used for controlling the movement of the thread are relatively low.
  • FIGS 1 and 2 show a device of the prior art as described in the review "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, June 1978.
  • the printing control device comprises an armature 10 fixed to the printing wire 12.
  • the armature is held in its initial or rest position, against the rear stop 14, by the permanent magnet 16.
  • the rear stop consists of a magnetic material with low reluctance, such as soft iron.
  • the frame 10 moves inside a plastic casing 20, this casing containing the permanent magnet 16 and an electromagnet 18.
  • a stop front 24, made of magnetic material, is in contact with a magnetic box 22 to define a low reluctance path.
  • a space 26 is provided between the frame 10 and the stop 24, and its length is equal to the desired displacement of the wire 12.
  • the magnetic circuit in which the flux created by the electromagnet 18 flows, comprises the magnetic box 22, the front stop 24 and the frame 10. Due to the structure of the non-magnetic casing 20, the magnetic force produced by the electromagnet 18 must be relatively large to overcome that produced by the permanent magnet 16, which is a disadvantage for the control device.
  • FIGS. 3 and 4 describe the ideal action of a permanent magnet .40 in the form of a hollow cylinder on a magnetic bar 42 placed at the center of the permanent magnet 40.
  • the magnetic force applied by the magnet permanent 40 at the bar 42 is such that the bar 42 arrives in an equilibrium position when its medium is in the center of the magnet 40. This is due to the fact that the magnetic path having the lowest reluctance is obtained when the bar 42. is centrally disposed in the magnet 40.
  • Figure 4 is a graphic representation of the magnetic force exerted on the bar 42 by the magnet 40 when the bar 42 is moved over a distance d.
  • a positive force (+ F) is defined on the right, a negative force (-F) on the left; a positive movement (+ d) is defined as the movement of the bar 42 to the right and a negative movement (-d) is defined as the movement of the bar 42 to the left.
  • the position of the bar 42 shown in Figure 3 is the equilibrium position.
  • the induced magnetic force increases on the bar 42 until a maximum force is reached.
  • the forces applied to the bar 42 remain relatively constant, which is shown by the flat part 44 of the curve in FIG. 4. After the bar 42 has been sufficiently distant from the magnet 40, the forces applied to it rapidly decrease and become zero.
  • the permanent magnet assembly 40 - bar 42 can be compared to the permanent magnet assembly 16 - armature 10. It is desirable that the forces exerted on the armature 10 correspond to the flat part 44 of FIG. 4. Given the low possible movement of the armature 10 relative to the length of the magnet 16, it could be considered that the forces applied to this armature actually correspond to the flat part 44. But, by the structure of the control device of Figure 1 , the representation of the magnetic force exerted by the magnet 16 does not correspond to that of Figure 4. In fact, the permeability of the stopper 14 is much greater than that of the casing 20, which causes an imbalance in the diagram of the forces exerted on the reinforcement and a non-linearity of the action of the forces during the displacement of the bar.
  • the present invention overcomes the drawbacks presented by the device of Figure 1.
  • the control device of Figure 5 comprises a frame 50 connected to the printing wire 52 which is in position rest against the back gauge 54.
  • the rear stop 54 in the embodiment of Figure 5 is made of a very hard non-magnetic metallic material. It has been found that cobalt sold under the brand name "Stellite” by Haynes Stellite Incorporated is a suitable material. In addition, the rear stop 54 could be of hardened beryllium copper.
  • the rear stop 54 being made of non-magnetic material, the diagram of the forces exerted by the permanent magnet 56 is very close to the theoretical diagram of FIG.
  • the material making up the rear stop must be made of a very hard material because of the very high number of times it is struck by the armature 10 (several billion times ) after de-energizing the electromagnet 58.
  • the control device of FIG. 5 also includes the electromagnet 58 and the plastic casing 60 containing the permanent magnet 56 and the electromagnet 58.
  • the permanent magnet 56 is a hollow cylinder made, for example, by an alloy cobalt-samarium and is arranged so that the north pole is opposite the stop 54.
  • the electromagnet 58 is also in the form of a hollow cylinder having the same internal diameter as the permanent magnet 56 and disposed adjacent to this permanent magnet.
  • control device of Figure 5 comprises the housing of magnetic material 62 and the front stop 64 both made of a magnetic material such as soft iron.
  • the front stop 64 is arranged so as to form a gap 66 between the frame 50 and the front stop 64 of a length equal to the length of the desired movement of the wire 52.
  • the structure of the casing 20 made it necessary to supply a strong supply to the electromagnet 18 because the path of the magnetic flux exhibited a significant reluctance. This was mainly due to the wide interval not magnetic existing between the left end of the electromagnet and the armature 50, as well as the magnetic insulator separating the electromagnet from the magnet 16.
  • a crown 76 is disposed between the magnet 56 and the electromagnet 58, this crown being in contact with the housing.
  • This crown 76 is also constituted by a magnetic material such as soft iron.
  • the purpose of the crown 76 is to ensure a better magnetic circuit trajectory for the electromagnet 58 so that the flux flows with less reluctance, through the case 62 and the crown 76, in the frame 50. This allows the application of less power to the conductors 68 and 70 connected to the electromagnet 58.
  • the control device of FIG. 5 also includes a plating of non-magnetic material such as chromium on the end 72 of the front stop 64. This thin plating makes it possible to eliminate any residual effect of the flow of the flux from the magnet permanent 56 through the housing 62 and the front stop 64, an effect which tended to attract the armature 50 towards the front stop 64 after the electromagnet 58 had de-energized.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Impact Printers (AREA)
  • Electromagnets (AREA)
  • Coating With Molten Metal (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)

Abstract

1. Print element actuator for a wire printer of the type including : an electro-magnet (58) and a permanent magnet, each of them having the form of a hollow cylinder, an armature (50) affixed to the print wire and positioned within said electro-magnet and said permanent magnet so that said armature can move a predetermined distance between a metal back stop (54) and a front stop (64), a first magnetic circuit, including the electromagnet, the armature and the front stop, and through which flux flows when the electro-magnet is energized, this flux controlling the forward movement of the print wire, a second magnetic circuit, including the permanent magnet and the armature and through which flux flows when the electro-magnet is not energized, this flux controlling the reverse movement of the print wire, this actuator being characterized in that : a cylindrically shaped hollow piece (76) is positioned between the electro-magnet and the permanent magnet to set up a magnetic circuit with the electro-magnet, the front stop and the armature and the backside stop is formed of a non-magnetic material.

Description

Domaine techniqueTechnical area

La présente invention concerne un dispositif de commande de fil d'impression pour une imprimante à matrice de fils et plus particulièrement, un type de dispositif de commande dans lequel aucun ressort ne contribue au mouvement avant ou arrière du fil d'impression.The present invention relates to a print wire control device for a wire matrix printer and more particularly, a type of control device in which no spring contributes to the forward or backward movement of the print wire.

Etat de la technique antérieureState of the prior art

Les imprimantes à matrice de fils sont bien connues dans l'art antérieur. Les imprimantes comprennent un ensemble de fils minces disposés en une colonne verticale. Chaque fil peut être actionné pour être entraîné vers l'avant contre un ruban et un milieu d'impression, tel que du papier, disposé autour de la platine de l'imprimante. Lorsque le fil est entraîné vers l'avant et entre en contact avec le ruban un point apparalt sur le papier. La commande de l'un ou de plusieurs des fils lors de leur déplacement latéral sur le papier, peut être utilisé pour provoquer l'impression de caractères, d'une manière connue dans l'art antérieur..L'une de ces imprimantes à matrice de fils est décrite dans le brevet No. 74 39730 déposé en France par la demanderesse le 16 octobre 1974 et un moyen de commande de cette imprimante est décrit dans le brevet No. 77 33124 déposé en France par la demanderesse le 27 octobre 1977.Wire matrix printers are well known in the prior art. The printers include a set of thin wires arranged in a vertical column. Each wire can be actuated to be driven forward against a ribbon and a printing medium, such as paper, disposed around the platen of the printer. When the thread is drawn forward and comes into contact with the ribbon, a point appears on the paper. The control of one or more of the threads during their lateral movement on the paper, can be used to cause the printing of characters, in a manner known in the prior art. wire matrix is described in patent No. 74 39730 filed in France by the plaintiff on October 16, 1974 and a control means of this printer is described in patent No. 77 33124 filed in France by the plaintiff on October 27, 1977.

Dans l'art antérieur, les dispositifs commandant le déplacement des fils vers l'avant consistent en un électroaimant auquel est appliqué un signal électrique pour créer un champ magnétique qui entraîne une armature vers l'avant. L'armature est connectée au fil d'impression et lorsqu'elle se déplace vers l'avant, elle entraîne le fil d'impression. Après la frappe du ruban qui provoque l'impression du point sur le papier, l'armature est ramenée dans sa position initiale ou de repos par un ressort. Une tête d'impression utilisant en combinaison un électroaimant et un ressort pour commander le mouvement du fil d'impression est décrite dans le brevet No. 71 32174 déposé en France par la demanderesse le 26 juin 1971 dans le brevet US-A- 4 046 244.In the prior art, the devices controlling the movement of the wires forwards consist of an electromagnet to which an electrical signal is applied to create a magnetic field which drives a frame towards the front. The frame is connected to the print wire and when it moves forward, it drives the print wire. After striking the ribbon which causes the dot to be printed on the paper, the reinforcement is returned to its initial or rest position by a spring. A print head using in combination an electromagnet and a spring to control the movement of the print wire is described in patent No. 71 32174 filed in France by the applicant on June 26, 1971 in US-A-4,046 244.

Les dispositifs de commande de fils utilisant un ressort présentent deux inconvénients. Le premier est que le ressort tend à s'user et peut ainsi être sujet à des défaillances mécaniques. Le deuxième est que le ressort applique des forces s'opposant au mouvement du fil lorsque celui-ci est entraîné vers l'avant pour frapper le ruban de façon que, lorsque le fil frappe le ruban, la force exercée dans le sens opposé par le ressort soit maximum. Ainsi, une alimentation plus importante doit être appliquée à l'électroaimant pour provoquer l'entralnement du fil vers l'avant avec une force suffisante assurant l'obtention d'un point imprimé de bonne qualité.Wire control devices using a spring have two drawbacks. The first is that the spring tends to wear out and can therefore be subject to mechanical failure. The second is that the spring applies forces opposing the movement of the wire when the latter is driven forward to strike the ribbon so that, when the wire strikes the ribbon, the force exerted in the opposite direction by the spring is maximum. Thus, a greater supply must be applied to the electromagnet to cause the wire to be drawn forward with sufficient force ensuring that a good quality printed point is obtained.

Afin de pallier les inconvénients dûs à la présence du ressort, plusieurs solutions ont été envisagées. Par exemple, le brevet US-A- 3 946 851 présente un dispositif dans lequel un aimant permanent commande le retour du fil d'impression après son mouvement vers l'avant.In order to overcome the drawbacks due to the presence of the spring, several solutions have been considered. For example, US-A-3,946,851 discloses a device in which a permanent magnet controls the return of the printing wire after its movement forward.

Le brevet US-A- 3 775 714 présente un dispositif dans lequel l'armature elle-même est un aimant permanent qui commande son propre retrait après avoir été déplacé vers l'avant. Ce dispositif présente un certain nombre d'inconvénients par le fait que l'armature étant un aimant permanent, elle présente une faible conduction magnétique.US-A-3,775,714 discloses a device in which the armature itself is a permanent magnet which controls its own removal after being moved forward. This device has a certain number of drawbacks in that the armature being a permanent magnet, it has low magnetic conduction.

Le brevet US-A- 3 755 766 présente un dispositif dans lequel l'aimant permanent est utilisé pour maintenir une armature contre une butée arrière et dans lequel l'électroaimant doit être excité avec une polarité déterminée pour entraîner l'armature vers l'avant et avec une polarité opposée pour l'entraîner vers l'arrière.US-A-3,755,766 discloses a device in which the permanent magnet is used to hold a frame against a rear stop and in which the electromagnet must be excited with a determined polarity to drive the frame forward and with a polarity opposite to drag it backwards.

L'article publié dans la revue "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, Juin 1978 et intitulé "Magnetic print wire actuator", décrit un dispositif de commande amélioré de fil d'impression comprenant un électroaimant, un aimant permanent et une armature fixée au fil d'impression.The article published in the journal "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, June 1978 and entitled "Magnetic print wire actuator", describes an improved printing wire control device comprising an electromagnet, a permanent magnet and an armature fixed to the printing wire.

Ce dispositif de commande comporte en outre un premier circuit magnétique comprenant l'électroaimant et l'armature qui sont traversés par un flux, lorsque l'électroaimant est excité, pour la commande du mouvement avant du fil d'impression, et un deuxième circuit magnétique comprenant l'armature et l'aimant permanent, qui, lorsque l'électroaimant n'est pas excité, sont traversés par un flux pour la commande du mouvement arrière du fil d'impression.This control device further comprises a first magnetic circuit comprising the electromagnet and the armature which are traversed by a flux, when the electromagnet is excited, for controlling the forward movement of the printing wire, and a second magnetic circuit comprising the armature and the permanent magnet, which, when the electromagnet is not energized, are traversed by a flux for controlling the backward movement of the printing wire.

Ce dispositif, s'il offre une nette améliortion par rapport aux dispositifs précédents, présente cependant certains inconvénients notamment des réluctances relativement importantes dans les circuits magnétiques, ce qui oblige à utiliser une forte alimentation pour commander l'électroaimant. De plus, l'action exercée par l'aimant permanent n'est pas constante lors du déplacement du fil d'impression.This device, if it offers a clear improvement compared to the previous devices, however presents certain drawbacks in particular of relatively large reluctances in the magnetic circuits, which obliges to use a strong supply to control the electromagnet. In addition, the action exerted by the permanent magnet is not constant during the displacement of the printing wire.

La présente invention pallie ces inconvénients grâce à un dispositif de commande de fil d'impression du genre comportant deux circuits magnétiques distincts pour déplacer le fil d'impression respectivement vers l'avant et vers l'arrière, ce dispositif comportant un anneau en matériau magnétique situé contre l'électroaimant et définissant un circuit magnétique avec l'électroaimant et l'armature.The present invention overcomes these drawbacks thanks to a printing wire control device of the kind comprising two separate magnetic circuits for moving the printing wire respectively forwards and backwards, this device comprising a ring made of magnetic material. located against the electromagnet and defining a magnetic circuit with the electromagnet and the armature.

La présente invention a également pour objet un dispositif de commande de fils d'impression dans lequel les forces magnétiques utilisées pour la commande du déplacement du fil sont relativement faibles.The present invention also relates to a device for controlling printing threads in which the magnetic forces used for controlling the movement of the thread are relatively low.

D'autres objets, caractéristiques et avantages de la présente invention ressortiront mieux de l'exposé qui suit, fait en référence aux dessins annexés à ce texte, qui représentent un mode de réalisation préféré de celle-ci.Other objects, characteristics and advantages of the present invention will emerge more clearly from the following description, made with reference to the drawings appended to this text, which represent a preferred embodiment thereof.

Brève description des figuresBrief description of the figures

  • La Figure 1 est une vue en coupe verticale d'un dispositif de commande de fil d'impression de l'art antérieur.Figure 1 is a vertical sectional view of a prior art print wire control device.
  • La Figure 2 est une vue en coupe prise selon la ligne 2-2 de la Figure 1.Figure 2 is a sectional view taken along line 2-2 of Figure 1.
  • La Figure 3 représente un aimant toroldal et le barreau aimanté le traversant.Figure 3 shows a toroldal magnet and the magnetic bar passing through it.
  • La Figure 4 représente graphiquement la force magnétique appliquée au barreau de la Figure 3 en fonction de son déplacement.Figure 4 graphically represents the magnetic force applied to the bar of Figure 3 as a function of its displacement.
  • La Figure 5 est une vue en coupe verticale de la réalisation préférée de la présente invention.Figure 5 is a vertical sectional view of the preferred embodiment of the present invention.
  • La Figure 6 est une vue en coupe prise selon la ligne 6-6 de la Figure 5.Figure 6 is a sectional view taken along line 6-6 of Figure 5.
Description de l'inventionDescription of the invention

Les Figures 1 et 2 représentent un dispositif de l'art antérieur tel que décrit dans la revue "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, Juin 1978. Le dispositif de commande d'impression comporte une armature 10 fixée au fil d'impression 12. L'armature est maintenue dans sa position initiale ou de repos, contre la butée arrière 14, par l'aimant permanent 16. La butée arrière est constituée par un matériau magnétique à faible réluctance, tel que du fer doux. L'armature 10 se déplace à l'intérieur d'un carter 20 en matière plastique, ce carter contenant l'aimant permanent 16 et un électroaiamant 18. Une-butée avant 24, en matériau magnétique, est en contact avec un boîtier magnétique 22 pour définir une trajectoire à faible réluctance. Un espace 26 est prévu entre l'armature 10 et la butée 24, et sa longueur est égale au déplacement désiré du fil 12.Figures 1 and 2 show a device of the prior art as described in the review "IBM Technical Disclosure Bulletin", Vol. 21, No. 1, page 15, June 1978. The printing control device comprises an armature 10 fixed to the printing wire 12. The armature is held in its initial or rest position, against the rear stop 14, by the permanent magnet 16. The rear stop consists of a magnetic material with low reluctance, such as soft iron. The frame 10 moves inside a plastic casing 20, this casing containing the permanent magnet 16 and an electromagnet 18. A stop front 24, made of magnetic material, is in contact with a magnetic box 22 to define a low reluctance path. A space 26 is provided between the frame 10 and the stop 24, and its length is equal to the desired displacement of the wire 12.

Lorsque l'électroaimant 18 est excité par application d'un courant aux deux conducteurs 30 et 32, une force magnétique, supérieure à celle due à l'aimant permanent 16, est appliqué à l'armature 10 et la force à se déplacer jusqu'à la butée 24. Le circuit magnétique, dans lequel s'écoule le flux créé par l'électroaimant 18, comprend le boîtier magnétique 22, la butée avant 24 et l'armature 10. De par la structure du carter non magnétique 20, la force magnétique produite par l'électroaimant 18 doit être relativement importante pour vaincre celle produite par l'aimant permanent 16, ce qui est un inconvénient pour le dispositif de commande.When the electromagnet 18 is excited by application of a current to the two conductors 30 and 32, a magnetic force, greater than that due to the permanent magnet 16, is applied to the armature 10 and the force to move up to at the stop 24. The magnetic circuit, in which the flux created by the electromagnet 18 flows, comprises the magnetic box 22, the front stop 24 and the frame 10. Due to the structure of the non-magnetic casing 20, the magnetic force produced by the electromagnet 18 must be relatively large to overcome that produced by the permanent magnet 16, which is a disadvantage for the control device.

Lorsque l'électroaimant n'est pas excité, son champ magnétique cesse et l'armature 10 est ramenée dans la position de la Figure 1 par la force magnétique exercée par l'aimant permanent 16. Dans ce cas, le flux s'écoule de l'aimant permanent 16 au travers de l'armature 10, créant la force magnétique qui entraîne l'armature en sens inverse ou vers l'arrière.When the electromagnet is not excited, its magnetic field ceases and the armature 10 is returned to the position of Figure 1 by the magnetic force exerted by the permanent magnet 16. In this case, the flux flows from the permanent magnet 16 through the armature 10, creating the magnetic force which drives the armature in reverse or backward.

On se reportera maintenant aux Figures 3 et 4 qui décrivent l'action idéale d'un aimant permanent .40 en forme de cylindre creux sur un barreau magnétique 42 disposé au centre de l'aimant permanent 40. La force magnétique appliquée par l'aimant permanent 40 au barreau 42 est telle que le barreau 42 arrive en position d'équilibre lorsque son milieu est au centre de l'aimant 40. Ceci est dû au fait que le chemin magnétique ayant la plus faible réluctance est obtenu lorsque le barreau 42.est disposé centralement dans l'aimant 40. La Figure 4 est une représentation graphique de la force magnétique exercée sur le barreau 42 par l'aimant 40 lorsque le barreau 42 est déplacé sur une distance d. Dans la Figure 4, une force positive (+F) est définie à droite, une force négative (-F) à gauche; un déplacement positif (+d) est défini comme le mouvement du barreau 42 à droite et un déplacement négatif (-d) comme le mouvement du barreau 42 à gauche.Reference will now be made to FIGS. 3 and 4 which describe the ideal action of a permanent magnet .40 in the form of a hollow cylinder on a magnetic bar 42 placed at the center of the permanent magnet 40. The magnetic force applied by the magnet permanent 40 at the bar 42 is such that the bar 42 arrives in an equilibrium position when its medium is in the center of the magnet 40. This is due to the fact that the magnetic path having the lowest reluctance is obtained when the bar 42. is centrally disposed in the magnet 40. Figure 4 is a graphic representation of the magnetic force exerted on the bar 42 by the magnet 40 when the bar 42 is moved over a distance d. In Figure 4, a positive force (+ F) is defined on the right, a negative force (-F) on the left; a positive movement (+ d) is defined as the movement of the bar 42 to the right and a negative movement (-d) is defined as the movement of the bar 42 to the left.

La position du barreau 42 représentée sur la Figure 3 est la position d'équilibre. Lorsque le barreau 42 est déplacé positivement ou négativement par rapport à la position d'équilibre, la force magnétique induite croit sur le barreau 42 jusqu'à ce qu'une force maximale soit atteinte. Puis, lorsque le barreau 42 poursuit son déplacement et que son centre s'éloigne encore de l'aimant 40, les forces appliquées au barreau 42 demeurent relativement constantes, ce qui est montré par la partie plate 44 de la courbe de la Figure 4. Après que le barreau 42 ait été suffisamment éloigné de l'aimant 40, les forces appliquées à celui-ci décroissent rapidement et deviennent nulles.The position of the bar 42 shown in Figure 3 is the equilibrium position. When the bar 42 is moved positively or negatively with respect to the equilibrium position, the induced magnetic force increases on the bar 42 until a maximum force is reached. Then, when the bar 42 continues to move and its center is still moving away from the magnet 40, the forces applied to the bar 42 remain relatively constant, which is shown by the flat part 44 of the curve in FIG. 4. After the bar 42 has been sufficiently distant from the magnet 40, the forces applied to it rapidly decrease and become zero.

L'ensemble aimant permanent 40 - barreau 42 peut être comparé à l'ensemble aimant permanent 16 - armature 10. Il est souhaitable que les forces exercées sur l'armature 10 correspondent à la partie plate 44 de la Figure 4. Etant donné le faible déplacement possible de l'armature 10 par rapport à la longueur de l'aimant 16, on pourrait considérer que les forces appliquées à cet armature correspondent effectivement à la partie plate 44. Mais, de par la structure du dispositif de commande de la Figure 1, la représentation de la force magnétique exercée par l'aimant 16 ne correspond pas à celle de la Figure 4. En effet, la perméabilité de la butée 14 est beaucoup plus grande que celle du carter 20, ce qui provoque un déséquilibre du diagramme des forces s'exerçant sur l'armature et une non linéarité de l'action des forces lors du déplacement du barreau.The permanent magnet assembly 40 - bar 42 can be compared to the permanent magnet assembly 16 - armature 10. It is desirable that the forces exerted on the armature 10 correspond to the flat part 44 of FIG. 4. Given the low possible movement of the armature 10 relative to the length of the magnet 16, it could be considered that the forces applied to this armature actually correspond to the flat part 44. But, by the structure of the control device of Figure 1 , the representation of the magnetic force exerted by the magnet 16 does not correspond to that of Figure 4. In fact, the permeability of the stopper 14 is much greater than that of the casing 20, which causes an imbalance in the diagram of the forces exerted on the reinforcement and a non-linearity of the action of the forces during the displacement of the bar.

La présente invention, telle que représentée sur les Figures 5 et 6 permet de pallier les inconvénients présentés par le dispositif de la Figure 1. Le dispositif de commande de la Figure 5 comprend une armature 50 connectée au fil d'impression 52 qui est en position de repos contre la butée arrière 54. La butée arrière 54 dans la réalisation de la Figure 5 est fabriquée en un matériau métallique non magnétique très dur. On a constaté qu'un cobalt vendu sous la marque "Stellite" par Haynes Stellite Incorporated est un matériau approprié. De plus, la butée arrière 54 pourrait être en cuivre au beryllium durci. La butée arrière 54 étant en matériau non magnétique, le diagramme des forces exercées par l'aimant permanent 56 est très proche du schéma théorique de la Figure 4, ce qui permet de considérer que la force effective exercée par l'aimant permanent 56 correspond réellement à la partie plate 44 de la courbe de la Figure 4. Cependant le matériau composant la butée arrière doit être constitué par un matériau très dur en raison du nombre très élevé de fois où il est frappé par l'armature 10 (plusieurs milliards de fois) après la désexcitation de l'électroaimant 58.The present invention, as shown in Figures 5 and 6 overcomes the drawbacks presented by the device of Figure 1. The control device of Figure 5 comprises a frame 50 connected to the printing wire 52 which is in position rest against the back gauge 54. The rear stop 54 in the embodiment of Figure 5 is made of a very hard non-magnetic metallic material. It has been found that cobalt sold under the brand name "Stellite" by Haynes Stellite Incorporated is a suitable material. In addition, the rear stop 54 could be of hardened beryllium copper. The rear stop 54 being made of non-magnetic material, the diagram of the forces exerted by the permanent magnet 56 is very close to the theoretical diagram of FIG. 4, which makes it possible to consider that the effective force exerted by the permanent magnet 56 really corresponds at the flat part 44 of the curve in FIG. 4. However, the material making up the rear stop must be made of a very hard material because of the very high number of times it is struck by the armature 10 (several billion times ) after de-energizing the electromagnet 58.

Le dispositif de commande de la Figure 5 comprend également l'électroaimant 58 et le carter en matière plastique 60 contenant l'aimant permanent 56 et l'électroaimant 58. L'aimant permanent 56 est un cylindre creux constitué, par exemple, par un alliage cobalt-samarium et est disposé de façon que le pôle nord soit en face de la butée 54. L'électroaimant 58 se présente également sous la forme d'un cylindre creux ayant même diamètre intérieur que l'aimant permanent 56 et disposé adjacent à cet aimant permanent.The control device of FIG. 5 also includes the electromagnet 58 and the plastic casing 60 containing the permanent magnet 56 and the electromagnet 58. The permanent magnet 56 is a hollow cylinder made, for example, by an alloy cobalt-samarium and is arranged so that the north pole is opposite the stop 54. The electromagnet 58 is also in the form of a hollow cylinder having the same internal diameter as the permanent magnet 56 and disposed adjacent to this permanent magnet.

De plus, le dispositif de commande de la Figure 5 comprend le bottier en matériau magnétique 62 et la butée avant 64 tous deux fabriqués en un matériau magnétique tel que du fer doux. La butée avant 64 est disposée de façon à former un entrefer 66 entre l'armature 50 et la butée avant 64 d'une longueur égale à la longueur du mouvement désiré du fil 52.In addition, the control device of Figure 5 comprises the housing of magnetic material 62 and the front stop 64 both made of a magnetic material such as soft iron. The front stop 64 is arranged so as to form a gap 66 between the frame 50 and the front stop 64 of a length equal to the length of the desired movement of the wire 52.

Ainsi que cela a été mentionné ci-dessus en référence à la Figure 1, la structure du carter 20 obligeait à fournir une forte alimentation à l'électroaimant 18 du fait que le chemin du flux magnétique présentait une réluctance importante. Ceci était principalement dû au large intervalle non magnétique existant entre l'extrémité gauche de l'électroaimant et l'armature 50, ainsi qu'à l'isolant magnétique séparant l'électroaimant de l'aimant 16.As mentioned above with reference to FIG. 1, the structure of the casing 20 made it necessary to supply a strong supply to the electromagnet 18 because the path of the magnetic flux exhibited a significant reluctance. This was mainly due to the wide interval not magnetic existing between the left end of the electromagnet and the armature 50, as well as the magnetic insulator separating the electromagnet from the magnet 16.

Comme on peut le voir sur la Figure 5, la partie du carter séparant l'aimant permanent et l'électroaimant est supprimée et une couronne 76 est disposée entre l'aimant 56 et l'électroaimant 58, cette couronne étant en contact avec le boîtier en matériau magnétique 62. Cette couronne 76 est également constituée par un matériau magnétique tel que le fer doux.As can be seen in Figure 5, the part of the housing separating the permanent magnet and the electromagnet is removed and a crown 76 is disposed between the magnet 56 and the electromagnet 58, this crown being in contact with the housing. made of magnetic material 62. This crown 76 is also constituted by a magnetic material such as soft iron.

La couronne 76 a pour but d'assurer une meilleure trajectoire de circuit magnétique pour l'électroaimant 58 de façon que le flux s'écoule avec moins de réluctance, au travers du bottier 62 et de la couronne 76, dans l'armature 50. Ceci permet l'application d'une alimentation moindre aux conducteurs 68 et 70 connectés à l'électroaimant 58.The purpose of the crown 76 is to ensure a better magnetic circuit trajectory for the electromagnet 58 so that the flux flows with less reluctance, through the case 62 and the crown 76, in the frame 50. This allows the application of less power to the conductors 68 and 70 connected to the electromagnet 58.

Le dispositif de commande de la Figure 5 comporte également un placage de matériau non magnétique tel que du chrome sur l'extrémité 72 de la butée avant 64. Ce placage mince permet de supprimer tout effet résiduel de l'écoulement du flux depuis l'aimant permanent 56 au travers du boîtier 62 et de la butée avant 64, effet qui tendait à attirer l'armature 50 vers la butée avant 64 après la désexcitation de l'électroaimant 58.The control device of FIG. 5 also includes a plating of non-magnetic material such as chromium on the end 72 of the front stop 64. This thin plating makes it possible to eliminate any residual effect of the flow of the flux from the magnet permanent 56 through the housing 62 and the front stop 64, an effect which tended to attract the armature 50 towards the front stop 64 after the electromagnet 58 had de-energized.

Bien que l'on ait décrit dans ce qui précède et représenté sur les dessins les caractéristiques essentielles de l'invention appliquées à un mode de réalisation préféré de celle-ci, il est évident que l'homme de l'art peut y apporter toutes modifications de forme ou de détail qu'il juge utiles, sans pour autant sortir du cadre de ladite invention.Although the essential characteristics of the invention applied to a preferred embodiment of the invention have been described in the foregoing and represented in the drawings, it is obvious that a person skilled in the art can provide all of them. modifications of form or detail which he judges useful, without departing from the scope of said invention.

Claims (6)

1.- Dispositif de commande d'éléments d'impression à fil du genre comprenant: un électroaimant (58) et un aimant permanent (56) ayant chacun la forme d'un cylindre creux, une armature (10) reliée au fil d'impression et située à l'intérieur de l'électroaimant et de l'aimant permanent, cette armature pouvant se déplacer, entre une butée arrière (54) et une butée avant (64), d'une distance prédéterminée, un premier circuit magnétique comportant l'électroaimant, l'armature et la butée avant et au travers duquel s'écoule un flux lorsque l'électroaimant est excité, ce flux contrôlant le déplacement vers l'avant du fil d'impression, un second circuit magnétique comportant l'aimant permanent et l'armature et au travers duquel s'écoule, lorsque l'électroaimant n'est pas excité, un flux qui contrôle le déplacement vers l'arrière du fil d'impression, ce dispositif étant caractérisé en ce qu'il comporte en outre: un élément creux de forme cylindrique (76) situé près de l'électroaimant de façon à former un circuit magnétique avec l'électroaimant, la butée avant et l'armature. 1.- Control device for wire printing elements of the kind comprising: an electromagnet (58) and a permanent magnet (56) each having the shape of a hollow cylinder, an armature (10) connected to the printing wire and located inside the electromagnet and the permanent magnet, this armature being able to move, between a rear stop (54) and a front stop (64), d '' a predetermined distance, a first magnetic circuit comprising the electromagnet, the armature and the front stop and through which flows a flux when the electromagnet is excited, this flux controlling the forward movement of the printing wire, a second magnetic circuit comprising the permanent magnet and the armature and through which flows, when the electromagnet is not excited, a flux which controls the rearward movement of the printing wire, this device being characterized in that it further comprises: a cylindrical hollow element (76) located near the electromagnet so as to form a magnetic circuit with the electromagnet, the front stop and the armature. 2.- Dispositif selon la revendication 1, caractérisé en ce que le premier circuit magnétique comporte en outre un boîtier (62) en matériau magnétique, le premier circuit magnétique étant constitué par l'électroaimant, le boîtier, la butée avant, l'armature et l'élément creux de forme cylindrique.2.- Device according to claim 1, characterized in that the first magnetic circuit further comprises a housing (62) of magnetic material, the first magnetic circuit being constituted by the electromagnet, the housing, the front stop, the armature and the element cylindrical hollow. 3.- Dispositif selon l'une des revendications 1 ou 2, caractérisé en ce que l'élément creux de forme cylindrique est située entre l'électroaimant et l'aimant permanent et les sépare.3.- Device according to one of claims 1 or 2, characterized in that the hollow element of cylindrical shape is located between the electromagnet and the permanent magnet and separates them. 4.- Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que la butée arrière est constituée par un matériau métallique non magnétique.4.- Device according to any one of the preceding claims, characterized in that the rear stop consists of a non-magnetic metallic material. 5.- Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que la butée arrière est constituée par un matériau métallique ayant un coefficient de dureté élevé.5.- Device according to any one of the preceding claims, characterized in that the rear stop consists of a metallic material having a high hardness coefficient. 6.- Dispositif selon l'une quelconque des revendications précédentes, caractérisé en ce que l'extrémité (72) de la butée avant est revêtue d'un placage de matériau non magnétique.6.- Device according to any one of the preceding claims, characterized in that the end (72) of the front stop is coated with a plating of non-magnetic material.
EP80101919A 1979-05-29 1980-04-10 Print element actuator for a wire printer Expired EP0019706B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4318379A 1979-05-29 1979-05-29
US43183 1979-05-29

Publications (2)

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EP0019706A1 true EP0019706A1 (en) 1980-12-10
EP0019706B1 EP0019706B1 (en) 1983-09-21

Family

ID=21925911

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Application Number Title Priority Date Filing Date
EP80101919A Expired EP0019706B1 (en) 1979-05-29 1980-04-10 Print element actuator for a wire printer

Country Status (8)

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EP (1) EP0019706B1 (en)
JP (1) JPS55161673A (en)
AU (1) AU529042B2 (en)
BR (1) BR8003344A (en)
CA (1) CA1136198A (en)
DE (1) DE3064880D1 (en)
ES (1) ES491905A0 (en)
IT (1) IT1151029B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997000174A2 (en) * 1995-06-13 1997-01-03 Tschida Mark J Printing apparatus and method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03126970A (en) * 1989-10-12 1991-05-30 Masanobu Nakamura Roll for copying machine and production thereof

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2126491A5 (en) * 1971-02-08 1972-10-06 Burroughs Corp
FR2228619A1 (en) * 1973-05-10 1974-12-06 Lrc Inc
FR2308178A1 (en) * 1975-04-16 1976-11-12 Bridon Engineering Ltd Magnetically operated actuator employing permanent and electro-magnets - is monostable or multistable and moves slide valve which may be made of magnetic
FR2325512A1 (en) * 1975-09-25 1977-04-22 Oki Electric Ind Co Ltd Electromagnet for operating printing wire on high speed printer - has armature movement damping unit positioned between armature and end cap (NL290377)

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2126491A5 (en) * 1971-02-08 1972-10-06 Burroughs Corp
FR2228619A1 (en) * 1973-05-10 1974-12-06 Lrc Inc
FR2308178A1 (en) * 1975-04-16 1976-11-12 Bridon Engineering Ltd Magnetically operated actuator employing permanent and electro-magnets - is monostable or multistable and moves slide valve which may be made of magnetic
FR2325512A1 (en) * 1975-09-25 1977-04-22 Oki Electric Ind Co Ltd Electromagnet for operating printing wire on high speed printer - has armature movement damping unit positioned between armature and end cap (NL290377)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997000174A2 (en) * 1995-06-13 1997-01-03 Tschida Mark J Printing apparatus and method
WO1997000174A3 (en) * 1995-06-13 1997-05-09 Mark J Tschida Printing apparatus and method
US5793392A (en) * 1995-06-13 1998-08-11 Tschida; Mark J. Printing apparatus and method

Also Published As

Publication number Publication date
IT1151029B (en) 1986-12-17
ES8103411A1 (en) 1981-02-16
IT8020721A0 (en) 1980-03-18
AU529042B2 (en) 1983-05-26
DE3064880D1 (en) 1983-10-27
BR8003344A (en) 1980-12-30
CA1136198A (en) 1982-11-23
EP0019706B1 (en) 1983-09-21
JPS6122638B2 (en) 1986-06-02
AU5813980A (en) 1980-12-04
JPS55161673A (en) 1980-12-16
IT8020721A1 (en) 1982-06-18
ES491905A0 (en) 1981-02-16

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