US3626340A - Reed switch assembly employing a magnetic screen - Google Patents

Reed switch assembly employing a magnetic screen Download PDF

Info

Publication number
US3626340A
US3626340A US27739A US3626340DA US3626340A US 3626340 A US3626340 A US 3626340A US 27739 A US27739 A US 27739A US 3626340D A US3626340D A US 3626340DA US 3626340 A US3626340 A US 3626340A
Authority
US
United States
Prior art keywords
screen
contacts
reed switch
switch assembly
reed
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
US27739A
Other languages
English (en)
Inventor
Frederick Percival Mason
Vishwanath Bansal
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.)
Creed and Co Ltd
Original Assignee
Creed and Co Ltd
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 Creed and Co Ltd filed Critical Creed and Co Ltd
Application granted granted Critical
Publication of US3626340A publication Critical patent/US3626340A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H36/00—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding
    • H01H36/0006—Permanent magnet actuating reed switches
    • H01H36/0013—Permanent magnet actuating reed switches characterised by the co-operation between reed switch and permanent magnet; Magnetic circuits
    • H01H36/002—Actuation by moving ferromagnetic material, switch and magnet being fixed

Definitions

  • REED SWITCH ASSEMBLY EMPLOYING A ABSTRACT A reed switch (for example, for a keyboard con- MAGNETIC SCREEN trolling a transmitter) is controlled by a reciprocable high- I Claim, 2 Drawing Figs permeability collar which can be slid axially onto the reed to screen the latter from a stationary magnet. This achieves low [52] US. Cl 335/205 crosswlk and permits high packing density [51] lnt.Cl ....l-l0lh 51/28 PATENIEU nu: nan 3,62 340 v lnvenlor F. P- MASON V. BANSAL Atlorne REED SWITCH ASSEMBLY EMPLOYING A MAGNETIC SCREEN This invention relates to a reed switch assembly.
  • a reed switch assembly comprising a plurality of reed contact units, a magnet system fixed relative to the contact units for closing their contacts, and a respective high permeability screen associated with each contact unit, each screen being movable between a first position at which it screens the associated contacts from the magnetic field of the magnet system thereby allowing the contacts to remain open, and a second position at which it allows the magnetic field to close the contacts.
  • FIG. 1 shows a conventional prior art reed switch assembly
  • FIG. 2 shows an embodiment of a reed switch assembly according to the invention.
  • a prior an assembly comprises a plurality of reed contact units 1 each having an associated magnet 2. With the magnets in the position shown the magnetic field across the reed contacts is sufiicient to close them. However, each magnet is movable relative to its associated contact unit to a position at which its magnetic field is not sufficient to close the respective reed contacts. This position is indicated by the broken line for the center magnet of FIG. 1. Thus each contact unit can be selectively controlled by movement of its associated magnet.
  • a disadvantage of this arrangement is that if a high packing density of reed contact units is desired, crosstalk between adjacent magnet contact unit pairs becomes sufficiently great for the reliable controlling of the contact units to be impaired.
  • FIG. 2 shows schematically a reed switch assembly which to some extent overcomes this disadvantage.
  • the assembly comprises a plurality of parallel reed contact units 1, and a magnet system 3 fixed relative to the contact units for closing their contacts.
  • the magnet system consists of a single permanent magnet magnetized as shown but it could comprise fixed individual magnets or electromagnets which could be deenergized when the assembly is not in use.
  • Each contact unit I is surrounded by a respective high permeability hollow cylindrical screen 4, and when these are in the positions shown they screen their associated reed contacts from the magnetic field of the permanent magnet 3 thereby allowing the contacts to remain open despite the magnetic field.
  • each screen 4 is movable in a direction parallel to the axis of its associated contact unit to a position at which it allows the magnetic field of the magnet system to close the contacts. This position is shown for the center screen by the broken lines.
  • the contact units are selectively controllable by moving the screens 4.
  • the axial movement of the screen is greatly exaggerated in the drawing; in practice a movement of a few millimeters would be sufficient.
  • a practical application of the assembly described with reference to FIG. 2 is in an electronic keyboard controlling a transmitter of, say, a teleprinter.
  • the screens are selectively movable in response to the depression of selected keys.
  • Each screen can be moved by a stifi wire or strip attached at one end to the screen and extending in the direction of movement of the screen. It is not necessary for the wire or strip to support the entire weight of the screen, since the latter can be at least partly supported by the associated contact unit.
  • screens from initially flat rectangular portions of high permeability material which are bent into a cylindrical shape, but screens of other configuration are possible. Furthermore, in the case of screens which do not substantially surround their contact units, their direction of movement need not be parallel to the axis of the contact units.
  • a reed switch assembly comprising a plurality of reed contact units, a magnet system fixed relative to the contact units for closing their contacts, and a respective high permeability screen associated with each contact unit, each screen being formed as a hollow cylinder surrounding the associated contact unit, each screen being movable in a direction substantially parallel to the axis of its associated contact unit between a first position at which it screens the associated contacts from the magnetic field of the magnet system thereby allowing the contacts to remain open and a second position at which it allows the magnetic field to close the contacts.

Landscapes

  • Push-Button Switches (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Input From Keyboards Or The Like (AREA)
US27739A 1969-04-16 1970-04-13 Reed switch assembly employing a magnetic screen Expired - Lifetime US3626340A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1933769 1969-04-16

Publications (1)

Publication Number Publication Date
US3626340A true US3626340A (en) 1971-12-07

Family

ID=10127668

Family Applications (1)

Application Number Title Priority Date Filing Date
US27739A Expired - Lifetime US3626340A (en) 1969-04-16 1970-04-13 Reed switch assembly employing a magnetic screen

Country Status (6)

Country Link
US (1) US3626340A (de)
JP (1) JPS4812706B1 (de)
AU (1) AU1386270A (de)
DE (1) DE2017346A1 (de)
FR (1) FR2043377A5 (de)
GB (1) GB1259355A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993988A (en) * 1975-06-02 1976-11-23 Walter John W Intrusion detection apparatus to signal movement of a partition
US5874878A (en) * 1997-04-28 1999-02-23 Jackson, Jr.; John T. Magnetic proximity switch system with slide-by anti-defeat machanism
US5877664A (en) * 1996-05-08 1999-03-02 Jackson, Jr.; John T. Magnetic proximity switch system
US5929731A (en) * 1996-05-08 1999-07-27 Jackson Research, Inc. Balanced magnetic proximity switch assembly

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155792A (en) * 1962-08-07 1964-11-03 Gen Electric Magnetic reed switch device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155792A (en) * 1962-08-07 1964-11-03 Gen Electric Magnetic reed switch device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3993988A (en) * 1975-06-02 1976-11-23 Walter John W Intrusion detection apparatus to signal movement of a partition
US5877664A (en) * 1996-05-08 1999-03-02 Jackson, Jr.; John T. Magnetic proximity switch system
US5929731A (en) * 1996-05-08 1999-07-27 Jackson Research, Inc. Balanced magnetic proximity switch assembly
US5874878A (en) * 1997-04-28 1999-02-23 Jackson, Jr.; John T. Magnetic proximity switch system with slide-by anti-defeat machanism

Also Published As

Publication number Publication date
DE2017346A1 (de) 1970-11-12
GB1259355A (de) 1972-01-05
AU1386270A (en) 1971-10-21
FR2043377A5 (de) 1971-02-12
JPS4812706B1 (de) 1973-04-23

Similar Documents

Publication Publication Date Title
US2397123A (en) Contact operation
US3448419A (en) Weatherproof pushbutton key set employing sealed contacts operated by a permanent magnet
GB1497002A (en) Data switches
US3059075A (en) Electrical switching device
US3626340A (en) Reed switch assembly employing a magnetic screen
US3162738A (en) Magnetically actuated switching device
US1876295A (en) Unpolarized electromagnetic relay
GB1466313A (en) Solid state and electromechanical relay
CA1008157A (en) Control circuit for an electromechanical actuator
IL37571A (en) Improvements relating to electrical switch devices
GB1451451A (en) Selective electrical switching means
US3764761A (en) Instantaneous switch
US3458839A (en) Locking reed and ball switches and matrices
DE59607931D1 (de) Koppelfeld
US2836674A (en) Rotary relay
GB1468313A (en) Electromagnetically operable switch arrangement
US2604542A (en) Cross-point switching mechanism
IT8022229A0 (it) Circuito di deflessione con controllo della ritraccia.
US3343110A (en) Adhesive relay
US3919676A (en) Permanent-magnet type relay
GB1038713A (en) Improvements relating to multiple position rotary switches
GB1059340A (en) Electrical switching device
US3374451A (en) Coordinate type crossbar switch utilizing variable reluctance
US2980891A (en) Electromagnetic impulse counter
GB1470263A (en) Switches