US3715695A - Electromagnetic switch having a flexible permanent magnet armature - Google Patents

Electromagnetic switch having a flexible permanent magnet armature Download PDF

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Publication number
US3715695A
US3715695A US00174731A US3715695DA US3715695A US 3715695 A US3715695 A US 3715695A US 00174731 A US00174731 A US 00174731A US 3715695D A US3715695D A US 3715695DA US 3715695 A US3715695 A US 3715695A
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US
United States
Prior art keywords
armature
magnet
electromagnetic switch
permanent magnet
pole
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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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US00174731A
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English (en)
Inventor
W Hofman
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US Philips Corp
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US Philips Corp
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Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3715695A publication Critical patent/US3715695A/en
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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/01—Relays in which the armature is maintained in one position by a permanent magnet and freed by energisation of a coil producing an opposing magnetic field

Definitions

  • Trifari PP NO-I 174,731 An electromagnetic switch provided with at least one magnetic circuit comprising a permanent magnet, the polarity of which is reversible by means of a magnetiz- [30] Foreign Apphcatmn Prwmy Data ing coil.
  • the permanent magnet is provided with pole Aug. 30, 1970 Netherlands ..7012890 pieces which magnetically cooperate with a flat flexible magnet of a movable armature.
  • the flexible mag- 52 U.S. Cl. ..335 229, 335/279, 335/303 net may be Provided with Soft-iron insertion Pieces in [51] Int.
  • the coercive force [58] H of the main magnet is smaller than 1,500 oersted Field of Search ..335/229, 230, 234, 279, 303
  • the invention relates toan electromagnetic switch including at least one magnetic circuit which comprises a permanent magnet provided with pole pieces which define an active air-gap. Part of the magnetic circuit is surrounded by a magnetizing coil, and a movable armature which is disposed opposite the air-gap and magnetically cooperates with the magnetic circuit.
  • the present invention provides a flat permanent magnet armature which is made of finely divided permanent-magnetic material bonded in a resilient synthetic material. This provides the advantage that in closing the armature the shock is absorbed by the resilience of the armature magnet.
  • the armature magnet has its rear surface secured to a soft-iron strip which serves as a short circuit for the lines of magnetic force which'emerge from the rear surface of the armature magnet.
  • each pole piece when the switch is in the closedposition both pole pieces contact the armature magnet, each pole piece magnetically co-operating with a magnetic pole of opposite polarity.
  • the switch in the closed positionof the switch only one pole piece contacts the armature magnet, the other pole piece magnetically co-operating with the soft-iron strip of the armature.
  • an auxiliary magnet is arranged in this air-gap between the pole pieces.
  • each part of the armature magnet which co-operates with the pole pieces is provided with a flat soft-iron insertion piece which serves as a pole piece.
  • FIG. 1 is a cross-sectional view of an embodiment of the invention in which the armature magnet cooperates with either pole piece,
  • FIG. 2 is a cross-sectional view of another embodiment of the invention in which the armature magnet magnetically co-operates with one pole piece,
  • FIG. 3 is a cross-sectional view of a modification of the embodiment shown in FIG. 2 in which the armature magnet is provided with an insertion piece, I
  • FIG. 4 is a cross-sectional view of a modification of the switch of FIG. 2 provided with an auxiliary magnet
  • FIG. 5 is a cross-sectional view of a switch according to the invention in which the armature magnet is provided with a different insertion piece, and
  • FIG. 6 shows a tape drive for a magnetic recording and play-back apparatus provided with a switch according to the invention.
  • a switch comprises a magnetic circuit 1 and an armature 2 which co-operate magnetically.
  • the magnetic circuit includes a cylindrical permanent main magnet 3, which at either end is provided with a soft-iron pole piece 4 and 5 respectively.
  • the main magnet 3 is axially magnetized so that the pole piece 5 is a north pole and the pole piece 4 is a south pole.
  • The. polepieces are L-shaped, coplanar limbs 6 and 7 defining an air-gap 8.
  • the cylindrical main magnet 3 is surrounded substantially throughout its length by a magnetizing coil 9.
  • the armature comprises a flat soft-iron strip 11 arranged for rotation (not shown).
  • auxiliary magnet 12 which in the closed position of the switch is in contact with the limbs 6 and 7 of the pole pieces 4 and 5 respectively substantially throughout its entire upper surface.
  • This upper surface comprises two unlike magnetic poles which each are disposed opposite one of the limbs 6 and 7 and have signs opposite to those of the magnetic poles of the contacting limbs; thus a north pole N lies opposite the south pole S of the limb 6, and a south pole S lies opposite the north pole N of the limb
  • the armature magnet 12 is made of a plasto-ferrite known under the trade-name P 120, thepolarity of which is not readily reversible.
  • the coercive force He is 2,200 oersted and the (BI-I),,,, is 12' 10.
  • the switch Under normal conditions, i.e., when no current flows through the magnetizing coil 9, the switch is closed.
  • the magnetic poles of the magnetic circuit 1 constituted by the limbs 7 and 6 of the pole pieces 5 and 4 attract the magnetic pole of opposite sign of the armature magnet 12.
  • the path of the lines of magnetic force is indicated by arrows in FIG. 1.
  • the magnetic circuit is closed by a soft-iron armature 11.
  • the switch is closed.
  • the force of this closure is absorbed by the resilience of the material of the armature magnet.
  • FIG. 2 shows a modified embodiment of the switch according to the invention.
  • the magnetic circuit 1 comprises a main magnet 3 having 'pole pieces 4 and 5-which is surrounded by a magnetizing coil.
  • the armature comprises, similarly to that of the preceding embodiment, a soft-iron strip ll and an armaturemagnet 'l6.
  • the pole piece 4 is L- shaped, however, the limb 14 which contacts'the armature magnet 16 is lengthened. Its length is nearly equal to the length of the armature magnet 16.
  • the pole piece consists of a single flat limb.
  • the armature magnet 16 is magnetized in the transverse direction.
  • FIG. 3 shows a similar construction, howev'en 'the armature magnet is of a different structure.
  • Thearmature magnet 20 is lengthened and has an extension 22 of reduced height at the region of the pole piece 5, the end 15 of which is shortened.
  • the height of the extension 22 is made up to the height of the remainder of the armature magnet by a soft-iron insertion piece 23.
  • the extension 22 is also magnetized in the transverse direction, however, its magnetization is opposite to that of the part 20.
  • an auxiliary magnet'30 is interposed between an end 31 of the limb 14 and a lateral face 32 of the pole piece 5.
  • This auxiliary magnet 30 is flat'and magnetized in the transverse direction. It is made of plactoferrite P 120 and has a north pole N facing the lateral face 32 and a south pole S facing the end 31.
  • the auxiliary magnet compels the lines of magnetic force to follow more accurately the path shown by ar- TOWS
  • the switch shown in FIG. 5 is of a different structure. However, its operation is equal to that of the preceding embodiments.
  • the magnetic circuit comprises a main magnet 40 arranged centrally of a soft-iron circuit comprising an upper plate 41, a lower plate 42 and a pot-shaped rim 43.
  • the main magnet 40 is surrounded by a magnetizing coil 44.
  • The-upper plate 41 together with the rim 43 defines an annular air-gap 45.
  • the armature 2 which is shown in cross-section comprises a soft-iron strip 46 and an armature magnet 47, the edge portion 48 of whichisthinner thanthe in a direction opposite to that of he central portion 49.
  • a soft-iron annular insertion piece 50 is arranged on the edge portion of the armature magnet.
  • the upper plate 41 magnetically'co-operates with the central portion 49,...an'd a rim;43co-operates with the insertion piece 50.
  • FIG. 6 shows a use of the switch according to the invention.
  • the switch operates the drive of a magnetic recording and/or play-back apparatus.
  • the switch 60 comprises a magnetic circuit 61 of the aforedescribed type which is fixed.
  • the armature 62 is arranged for rotation about a spindle 63.
  • a rubber thrust roller 65 which in the closed position of the switch presses a magnetic tape against a "capstan, 66.
  • the capstan 66 is arranged centrally in a What is claimed is:
  • An electromagnetic switch as claimed in claim 1 further comprising a flat soft-iron insertion piece which serves as a pole piece provided on each part of the armature magnet which magnetically cooperates with the pole piece.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnets (AREA)
US00174731A 1970-08-31 1971-08-25 Electromagnetic switch having a flexible permanent magnet armature Expired - Lifetime US3715695A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7012890A NL7012890A (fr) 1970-08-31 1970-08-31

Publications (1)

Publication Number Publication Date
US3715695A true US3715695A (en) 1973-02-06

Family

ID=19810915

Family Applications (1)

Application Number Title Priority Date Filing Date
US00174731A Expired - Lifetime US3715695A (en) 1970-08-31 1971-08-25 Electromagnetic switch having a flexible permanent magnet armature

Country Status (7)

Country Link
US (1) US3715695A (fr)
AT (1) AT314018B (fr)
BE (1) BE771966A (fr)
DE (1) DE2139405C3 (fr)
FR (1) FR2103649B1 (fr)
GB (1) GB1350614A (fr)
NL (1) NL7012890A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4479103A (en) * 1979-04-05 1984-10-23 Motor Magnetics Polarized electromagnetic device
EP0263581A2 (fr) * 1986-08-08 1988-04-13 Seiji Yamamoto Dispositif d'actionnement magnétique
WO2008107224A3 (fr) * 2007-03-07 2008-11-20 Bosch Gmbh Robert Circuit magnétique d'électrovanne

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2520152B1 (fr) * 1982-01-20 1986-02-28 Telemecanique Electrique Electro-aimant a equipage mobile a aimant permanent a fonctionnement monostable
DE3225777C2 (de) * 1982-07-09 1984-05-10 Siemens AG, 1000 Berlin und 8000 München Polarisiertes Relais
FR2554960B1 (fr) * 1983-11-16 1987-06-26 Telemecanique Electrique Electro-aimant comprenant des culasses et une armature comportant un aimant permanent muni sur ses faces polaires, de pieces polaires debordant de l'axe de l'aimant, cet axe etant perpendiculaire a la direction du mouvement

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE57706C (de) * Dr. H. HEYNE in Landsbut, Bayern Trockenverfahren für Leim- und Gelatinelösungen
DE968353C (de) * 1952-01-18 1958-02-06 Siemens Ag Anordnung zur Verhuetung von Kontaktprellungen und zur Herabsetzung des Schaltgeraeusches bei elektromagnetisch betaetigten Schaltgeraeten

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4479103A (en) * 1979-04-05 1984-10-23 Motor Magnetics Polarized electromagnetic device
EP0263581A2 (fr) * 1986-08-08 1988-04-13 Seiji Yamamoto Dispositif d'actionnement magnétique
EP0263581A3 (fr) * 1986-08-08 1989-02-22 Seiji Yamamoto Dispositif d'actionnement magnétique
WO2008107224A3 (fr) * 2007-03-07 2008-11-20 Bosch Gmbh Robert Circuit magnétique d'électrovanne

Also Published As

Publication number Publication date
NL7012890A (fr) 1972-03-02
DE2139405A1 (de) 1973-08-30
FR2103649B1 (fr) 1976-09-03
BE771966A (fr) 1972-02-29
DE2139405C3 (de) 1978-11-30
AT314018B (de) 1974-03-11
GB1350614A (en) 1974-04-18
FR2103649A1 (fr) 1972-04-14
DE2139405B2 (de) 1978-04-06

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