US3729697A - Bistable electric switch - Google Patents

Bistable electric switch Download PDF

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Publication number
US3729697A
US3729697A US00196321A US3729697DA US3729697A US 3729697 A US3729697 A US 3729697A US 00196321 A US00196321 A US 00196321A US 3729697D A US3729697D A US 3729697DA US 3729697 A US3729697 A US 3729697A
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US
United States
Prior art keywords
armature
magnet
actuating
switch assembly
poles
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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
Application number
US00196321A
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English (en)
Inventor
H Hounsgard
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Danfoss AS
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Danfoss AS
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Publication date
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Publication of US3729697A publication Critical patent/US3729697A/en
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    • 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
    • H01H36/02—Switches actuated by change of magnetic field or of electric field, e.g. by change of relative position of magnet and switch, by shielding actuated by movement of a float carrying a magnet
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/30—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats
    • G01F23/56—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by floats using elements rigidly fixed to, and rectilinearly moving with, the floats as transmission elements

Definitions

  • ABSTRACT The invention relates to a bistable electric switch assembly of the type having an actuating permanent magnet pivotally mounted relative to a central axis and held in each of its stable positions by two soft iron pole pieces offset from the central plane.
  • the actuating magnet is responsive to an operating permanent magnet arranged to pass one of the poles of the actuating magnet and disposed at a right angle relative thereto.
  • Fixed and movable contacts are provided with the movable contact being mounted on an armature which forms a variable width air gap with one of the pole pieces.
  • a spring biases the armature and the movable contact towards an open position.
  • a substantial part of the magnetic flux extends across the air gap which sequentially causes closing and opening forces to be exerted on the armature of the movable contact depending on the position of the permanent actuating magnet.
  • This invention relates to a bistable electric switch having a contact actuating permanent magnet which is mounted to swing about a central axis and is held in each of the stable positions by two soft-iron pole pieces offset from the central plane, the actuating magnet being responsive to an operating permanent magnet arranged to pass one of the poles of the actuating magnet and disposed substantially at right-angles to the actuating magnet, and in which the movable contact is mounted on a soft-iron armature.
  • Bistable electric switches of this kind offer the advantage that the switching mechanism can be fully encased and can be actuated from the outside with the aid of the operating permanent magnet, i.e. without any mechanical connection.
  • the object of the invention is to provide a bistable electric switch of the initially described kind in which on the one hand the actuating permanent magnet can be readily displaced, while on the other hand fairly large forces can be produced in the contact system.
  • this object is achieved by forming the soft-iron pole pieces on fixed pole shoes each associated with a pole of the contact actuating permanent magnet and offset on the same side from the central plane, by biassing the movable contact by an opening spring, and by arranging that the soft-iron armature forms with one of the pole shoes an air-gap of variable size across which passes a substantial portion of the magnetic flux received by the soft-iron pole piece in that position of the actuating permanent magnet which corresponds with the closed position of the switch.
  • the fixed soft-iron pole pieces enable well-defined conditions to be established that permit the actuating permanent magnet to be displaced from the outside by the use of small forces.
  • the closing force in the contact system depends upon the air-gap between the soft-iron armature and one of the pole shoes. Since this air-gap may become zero, very large closing forces are obtained simply with the magnetic forces present in the system.
  • the force applied by the opening spring can be selected to cover a wide range. If it is to be used merely for holding the system open, it may be very weak and if it is intended to reinforce the opening action or to act as a closing spring for a co-operating contact,'it can be made stronger within the range governed by the magnetic closing force.
  • the pole shoes have salient poles and extensions projecting slightly beyond the central plane. In this way, a greater portion of the magnetic flux is conducted across the pole shoes.
  • the opening spring is a leaf spring which carries the movable'contact, so that the contact carrier and contact spring are constituted by a single component.
  • An advantageous form of construction is one in which the soft-iron armature is constituted by an angled element, the free end of one of the limbs of which helps to define the air-gap, and the other limb of which is fitted to the leaf spring and carries the movable contact. Then, only one attachment means is required for securing the contact and angled elements to the leaf spring. Furthermore, the contact is reinforced by the angled element.
  • the pivoting movement of the switching permanent magnet may be limited by a stop. This results in very precisely defied stable positions and therefore also in precisely defined forces in the switch.
  • FIG. 1 is a schematic illustration of the switch of the invention used in conjunction with a float
  • FIG. 2 is a horizontal longitudinal section through the switch with the contacts closed
  • FIG. 3 is an illustration of the switch of FIG. 2 with the contacts open.
  • the switch consists of a working assembly indicated generally at l and an operating permanent magnet 2.
  • the latter is connected by way of a rod 3 to a float 4 and is moved up and down in the directions indicatedby the arrow 6, by the change in the level ofa liquid 5.
  • the working assembly is contained in a glass envelope 8 closed by a ceramic plug 7. Fitted on the plug 7 are a carrier 9 for a fixed contact 10, and a bracket 1 1 on which is mounted by way of a bronze spring 12 biassed in the opening direction, an angled soft-iron armature 13 carrying a movable contact 14.
  • the bracket 11 also carries a bowed element 15 in which a switching or contact actuating permanent magnet 16 is mounted to pivot about its central axis 17.
  • a pole shoe 19, made of soft-iron and having a salient pole 20, is secured to a further bowed element 18.
  • a third bowed element 21 carries a soft-iron pole shoe 22 having a salient pole 23.
  • the two poles 20 and 23 are offset on the same side in relation to the central plane 24.
  • Each of the pole shoes extends from the pole to a point slightly beyond the central plane 24.
  • a web 25 on the bracket 11 acts as a stop for the switching permanent magnet 16 in its two switching positions.
  • the pole shoe 19 and the armature 13 form an air-gap 26 extending parallel with this central plane. In FIG. 2 this air-gap is zero, and in FIG. 3 it is at its widest.
  • the permanent switching magnet 16 occupies the position as illustrated.
  • the greatest portion of the magnetic flux lines emanating from the end face of the south pole S is concentrated at the pole and is passed across the air-gap 26 to the armature 13.
  • the magnetic flux lines emerge from the armature and pass through the air to the end face of the north pole N.
  • the contacts 10 and 14 may be made of silver, the carrier 9 and the bracket 11 of brass, and the spring 12 of bronze.
  • the south pole S of the switching permanent magnet 16 is attracted and snaps over into the position seen in FIG. 3. It is held there in a stable manner even upon continued movement of the magnet 2, since the salient pole 23, in conjunction with the magnetic forces, holds the magnet 16 in the position shown in FIG. 3.
  • the magnetic conditions in the air-gap 26 first change since one portion of the magnetic flux, emanating from the end face of the south pole S of the switching permanent magnet 16, passes across the pole shoe 19, while the other portion passes across the armature 13. Consequently, not only does the force of attraction between the two softiron parts cease, but a repulsive force is even created.
  • the biased spring 12 provides further thrust in the direction for opening. Finally, the south pole of the magnet 16 encounters the spring 12, so that separation of the contacts takes place even if they are adhering to each other.
  • a bistable electric switch assembly comprising frame means, a permanent actuating magnet mounted on said frame means for pivotal movement about a fixed axis, two soft iron pole shoes attached to said frame in respective proximity to the ends of said actuating magnet and in magnetically cooperable relation thereto, a permanent operating magnet disposed at substantially a right angle to said actuating magnet near one of the poles of said actuating magnet and movable relative thereto, the poles of said operating magnet being alternately movable into close proximity to said one of said poles to alternately effect movement of said actuatinfg magnet, a movable switch contact mounted on a so ll'Ol'l armature, said soft lI'Ol'l armature being movable relative to said one of said pole shoes with which it forms a variable width air gap which varies between a zero opening and a predetermined opening, said armature being movable in response to being operatively contacted by said actuating magnet during movement thereof, and spring means biasing said armature away from

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Soil Working Implements (AREA)
US00196321A 1970-08-31 1971-11-08 Bistable electric switch Expired - Lifetime US3729697A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2043042A DE2043042C3 (de) 1970-08-31 1970-08-31 Magnetfeldbetätigter bistabiler elektrischer Schalter
US19632171A 1971-11-08 1971-11-08

Publications (1)

Publication Number Publication Date
US3729697A true US3729697A (en) 1973-04-24

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ID=25759654

Family Applications (1)

Application Number Title Priority Date Filing Date
US00196321A Expired - Lifetime US3729697A (en) 1970-08-31 1971-11-08 Bistable electric switch

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US (1) US3729697A (da)
DE (1) DE2043042C3 (da)
DK (1) DK136680C (da)
GB (1) GB1365104A (da)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4483193A (en) * 1981-10-02 1984-11-20 Cesare Bonetti S.P.A. Magnetic level indicators
US4865073A (en) * 1987-09-14 1989-09-12 Vilter Manufacturing Corporation Liquid level control for refrigeration system
DE29500362U1 (de) * 1995-01-11 1995-02-23 ELB-Füllstandsgeräte Bundschuh GmbH + Co, 64625 Bensheim Bistabile Schalteranordnung
US20100102906A1 (en) * 2007-02-06 2010-04-29 Polycontact Ag Magnetically operated switch
US20120312594A1 (en) * 2010-03-01 2012-12-13 Illinois Tool Works Inc. Lid lock with magnetic anti-tamper feature
US8638185B1 (en) * 2012-12-12 2014-01-28 Fu Tai Hua Industry (Shenzhen) Co., Ltd. Magnetically-sensitive switch and electronic device with magnetically-sensitive switch
US20140204512A1 (en) * 2011-08-11 2014-07-24 Wistron Corporation Magnetic switch device and electronic device having the same
CN107564765A (zh) * 2017-08-25 2018-01-09 中国电子科技集团公司第四十九研究所 一种浮球液位开关弹性触点
CN112263907A (zh) * 2020-09-28 2021-01-26 张红社 一种节能环保型的化工废气喷淋设备
CN115547744A (zh) * 2022-10-17 2022-12-30 福州大学 一种双向旋转式双稳态永磁操动机构

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2671834A (en) * 1952-01-23 1954-03-09 Mcdonnell & Miller Inc Level controlled switch mechanism
US3121146A (en) * 1959-06-12 1964-02-11 Atomic Energy Authority Uk Position indicating devices

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2671834A (en) * 1952-01-23 1954-03-09 Mcdonnell & Miller Inc Level controlled switch mechanism
US3121146A (en) * 1959-06-12 1964-02-11 Atomic Energy Authority Uk Position indicating devices

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4483193A (en) * 1981-10-02 1984-11-20 Cesare Bonetti S.P.A. Magnetic level indicators
US4865073A (en) * 1987-09-14 1989-09-12 Vilter Manufacturing Corporation Liquid level control for refrigeration system
DE29500362U1 (de) * 1995-01-11 1995-02-23 ELB-Füllstandsgeräte Bundschuh GmbH + Co, 64625 Bensheim Bistabile Schalteranordnung
US20100102906A1 (en) * 2007-02-06 2010-04-29 Polycontact Ag Magnetically operated switch
US8736406B2 (en) * 2010-03-01 2014-05-27 Illinois Tool Works Inc. Lid lock with magnetic anti-tamper feature
US20120312594A1 (en) * 2010-03-01 2012-12-13 Illinois Tool Works Inc. Lid lock with magnetic anti-tamper feature
US20140204512A1 (en) * 2011-08-11 2014-07-24 Wistron Corporation Magnetic switch device and electronic device having the same
US9019052B2 (en) * 2011-08-11 2015-04-28 Wistron Corporation Magnetic switch device and electronic device having the same
US8638185B1 (en) * 2012-12-12 2014-01-28 Fu Tai Hua Industry (Shenzhen) Co., Ltd. Magnetically-sensitive switch and electronic device with magnetically-sensitive switch
CN107564765A (zh) * 2017-08-25 2018-01-09 中国电子科技集团公司第四十九研究所 一种浮球液位开关弹性触点
CN112263907A (zh) * 2020-09-28 2021-01-26 张红社 一种节能环保型的化工废气喷淋设备
CN112263907B (zh) * 2020-09-28 2022-07-29 山东派尼新材料股份有限公司 一种节能环保型的化工废气喷淋设备
CN115547744A (zh) * 2022-10-17 2022-12-30 福州大学 一种双向旋转式双稳态永磁操动机构

Also Published As

Publication number Publication date
DE2043042B2 (de) 1973-03-01
DE2043042A1 (de) 1972-03-09
DK136680C (da) 1978-04-10
DE2043042C3 (de) 1973-09-20
GB1365104A (en) 1974-08-29
DK136680B (da) 1977-11-07

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