US2518966A - Magnetic snap action switch - Google Patents

Magnetic snap action switch Download PDF

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Publication number
US2518966A
US2518966A US718636A US71863646A US2518966A US 2518966 A US2518966 A US 2518966A US 718636 A US718636 A US 718636A US 71863646 A US71863646 A US 71863646A US 2518966 A US2518966 A US 2518966A
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US
United States
Prior art keywords
switch
magnet
armature
lever arm
resilient
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
US718636A
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English (en)
Inventor
Wilson William Harry
Chinn Arthur John
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.)
Rheostatic Co Ltd
Original Assignee
Rheostatic 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 Rheostatic Co Ltd filed Critical Rheostatic Co Ltd
Application granted granted Critical
Publication of US2518966A publication Critical patent/US2518966A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H5/00—Snap-action arrangements, i.e. in which during a single opening operation or a single closing operation energy is first stored and then released to produce or assist the contact movement
    • H01H5/02—Energy stored by the attraction or repulsion of magnetic parts

Definitions

  • This invention relates to magnetic snap action switches, for use On alternating current circuits,
  • the moving contact being arranged to have a movement of separation from the fixed contact limited to an amount sufilcient only to prevent the restriking of an are at the voltage of the circuit broken and at such a speed as to reach this distance within the time of half a cycle.
  • the resilient lever is usually arranged by the ratio provided to give a greater movement atthe switch contacts than at the point where the initiating movement is applied and the movement of the resilient lever is equal to the switch contact travel.
  • the load on the end of the resilient lever at the moment of contact opening is equal to the-total pull of the magnet on the armature.
  • the load at the end of the opening movement is still substantially unaltered being lessened only by the decrease in the magnetic pull on the armature due to its having moved away from the magnet through the small opening distance.
  • a further object is to improve the stability and contact pressure of such switches by providing separate elements for the movement increasing lever and the resilience. By this separation it is possible to limit the movement of the resilience at its operative end to a minimum.
  • the load imposed by the magnet pull is in part cancelled by the'provision of a second armature mechanically attached to the first but mounted on the opposite side of the 2 magnet poles so that as one armature approaches the magnet the other recedesfrom it.
  • the resulting pull from the pair 01 armatures is adjusted by regulating the' gaps between each armature and the magnet.
  • the contact pressure is proportional to the flux change, but in switches in which the armature is carried on the end of a resilient lever the contact pressure realised is not equal to the force brought about by the flux change but is less by the amount of force used in bending the resilient lever through the switch movement.
  • the main lever carrying the armatures and contact is made non-resilient, the end remote from the armatures being suitably pivoted, the preferred form-being a. flexible strip used as a pivot by twisting action, but the force absorbed at this point, being virtually the pivot pin oi the lever,
  • the resilient transmission necessarily imposed between the slowly changing initiating force and the switch lever shall be provided by a separate element pressing the non-resilient switch lever, preferably at a point very near its pivot.
  • Fig. 1 is a side elevation partly in broken section, of a switch constructed in accordance with the invention
  • Fig. 2 is a sectional view taken on line 2-2 of Fig. 1
  • Fig. 3 is a plan view of the switch shown in Figs.
  • FIG. 1 show one arrangement of the elements of a switch constructed in accordance with our invention, in which a magnet I2 is mounted on a base l3 by a bracket H.
  • the switch as shown and described, comprises a pair of cooperating electrical contacts 6 and I, one of which is carried on a bracket 8 attached to the base l3, while the other is attached to the upper portion of the movabl armature Hi.
  • the extent of the movement of the armature assembly, including the contact 1, is limited by an adjustable stop 9 threaded into the base IS.
  • the position of the contact 6 and the stop 9 should be adjusted so that the gap between the armature ll and the magnet I2 is smaller than the gap between armature l6 and the magnet in both the open and closed positions of the switch contacts. This relationship'is to insure that the switch will be magnetically self-closing on release of pressure from the actuator 22.
  • the magnetic snap action switch therefore comprises a non-resilient switch lever arm carrying two armatures so arranged in relation to a magnet that while one armature approaches the magnet, the second armature is receding from it, their positions in relation to the magnet being such that in any position of the switch one armature remains slightly closer to the magnet than the other, and a resilient member adapted to press the rigid switch lever, such resilient member serving to store the initiating movement until sufiicient force is generated in it to operate the non-resilient switch.
  • the fulcrum of the lever may consist of a spring strip supporting the lever at its pivoted point, the pressure of the support being taken in the edgewise direction of the strip.
  • the very small angular movement of the switch lever acts at right angles to the plane 01 the support strip and is accommodated by a slight twisting of the strip.
  • a magnetic snap action switch comprising a magnet, a non-resilient switch lever arm carrying a pair of armatures respectively disposed on opposite sides of the magnet at unequal distances from the magnet and movable in unison relative to the magnet so that while one armature approaches the magnet the other recedes therefrom, a pair of switch contacts, one of which switch contacts is actuated by the non-resilient switch lever arm, the movement of the armature being limited in one direction by the closure of said switch contacts and limited in the opposite direction by a stop, the armature which was closer to the magnet in the closed position 01' the switch also remaining the closer of the two in the open position of the switch, and a resilient member adapted to press the non-resilient switch lever arm to move said closer armature in a direction away from the magnet, such resilient member serving to store an initiating movement until suflicient force is generated in it to move the lever arm in opposition to the resultant attractive force of the magnet on the pair of armatures.
  • a magnetic snap action switch comprising a magnet mountedin a fixed position, a non-resilient switch lever arm carrying a pair of armatures respectively disposed on opposite sides of the magnet at unequal distances from the magnet and movable in unison so that while one armature approaches the magnet the other recedes therefrom, means for so limiting the movement of the lever arm that the armature which was closer to the magnet in the closed position of the switch also remains the closer of the two in the open position of the switch, and a resilient member adapted to pess the non-resilient switch lever arm to move said closer armature in a direction away from the magnet against the attractive force consisting in the difference between the magnetic pull on the two armatures, such resilient member serving to store an initiating movement until sufiicient force is generated in it to move the lever arm in opposition to the resultant attractive iorce.
  • a magnetic snap action switch comprising a magnet mounted in a fixed position, a non-resilient switch lever arm carrying a pair of armatures respectively disposed on opposite sides of the magnet at unequal distances from the magnet and movable in unison so that while one armature approaches the magnet the other recedes therefrom, said lever arm being rigidly mounted on a spring strip in a position 'to pivot in a plane at right angles to the lengthwise dimension of the spring strip whereby when the lever arm is pivoted the spring strip is twisted, means for so limiting the movement of the lever arm that the armature which was closer to the magnet in the closed position of the switch also remains the closer of the two in the open position of the switch, and aresilient member adapted to press the non-resilient switch lever arm to move said closer armature in a direction away from the magnet against the attractive force consisting in the difference between the magnetic pull on the two armatures, such resilient member serving to store an initiating movement until suirlcient force is generated in it to move the lever arm in
  • a magnetic snap action switch as claimed in claim 1 characterized by including a spring strip to which the lever arm is attached and upon which the arm is pivoted, the arm being mounted for pivoting in a path approximately normal to the lengthwise direction of the strip and arranged to twist the strip when pivoted.
  • a magnetic snap action switch comprising a magnet, a switch lever arm carrying a pair of armatures respectively disposed on opposite sides of the magnet at unequal distances from the magnet and movable in unison relative to the magnet so that while one armature approaches the magnet the other recedes therefrom, a pair of switch contacts, one of which switch contacts is actuated by the switch lever arm, the movement of the armaures bein limited in one direction by the closure of the said switch contacts, and means tor so limiting the movement of the lever arm in the opposite direction that the armature which was the closer to the magnet in the closed position of the switch also remains the closer of the two armatures in the open position of the switch, whereby a force and a counterforce are exerted on said armatures, the resultant of said forces being in the same direction in all positions to said first contact and adapted to cooperate therewith, and means for so limiting the movement of said switch lever arm in switch opening direction that the one of said armatures which is the nearer to the magnet in switch closed position remains the near
  • a magnetic snap action switch comprising a first contact, a movable switch lever arm, a second contact carried by said switch lever arm and adapted to cooperate with said first contact in one position of the switch lever arm, a first magnetic means, a second magnetic means carried by said switch lever arm and having at least two magnetic elements for cooperation with said first magnetic means, one element being positioned on one side and another element on the opposite side of said first magnetic means; and means for maintaining one of said elements nearer to the first magnetic means than the other of said elements in all positions of the switch lever arm, whereby a force and a counterforce are exerted by one of said first and second magnetic means on the other of said first and second magnetic means, the resultant of said forces being in the same direction in all positions of switch lever arm.

Landscapes

  • Rotary Switch, Piano Key Switch, And Lever Switch (AREA)
  • Push-Button Switches (AREA)
US718636A 1946-01-09 1946-12-27 Magnetic snap action switch Expired - Lifetime US2518966A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB812/46A GB606055A (en) 1946-01-09 1946-01-09 Improvements in and connected with magnetic snap action switches

Publications (1)

Publication Number Publication Date
US2518966A true US2518966A (en) 1950-08-15

Family

ID=9710928

Family Applications (1)

Application Number Title Priority Date Filing Date
US718636A Expired - Lifetime US2518966A (en) 1946-01-09 1946-12-27 Magnetic snap action switch

Country Status (6)

Country Link
US (1) US2518966A (ko)
BE (1) BE470382A (ko)
CH (1) CH268298A (ko)
FR (1) FR939614A (ko)
GB (1) GB606055A (ko)
NL (1) NL72699C (ko)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3207877A (en) * 1959-03-02 1965-09-21 Satchwell Controls Ltd Thermostatic switch with permanent magnet induced snap action

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2635157A (en) * 1949-05-03 1953-04-14 Rheostatic Co Ltd Thermostatic control switch
DE1018508B (de) * 1954-05-25 1957-10-31 Ed Hartmann Fa Schnappschalter fuer elektrische Stromkreise
DE1266391B (de) * 1959-02-05 1968-04-18 Vedder Gmbh Geb Ausloesevorrichtung fuer Schalter und Relais

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1242038A (en) * 1916-02-15 1917-10-02 William E R Rademaker Vibrating self-interrupter for electric bells, &c.
US1651629A (en) * 1927-12-06 Tiltable-switch-adjusting means
CH169478A (de) * 1932-05-20 1934-05-31 Stotz Kontakt Gmbh Selbsttätiger Momentschalter.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1651629A (en) * 1927-12-06 Tiltable-switch-adjusting means
US1242038A (en) * 1916-02-15 1917-10-02 William E R Rademaker Vibrating self-interrupter for electric bells, &c.
CH169478A (de) * 1932-05-20 1934-05-31 Stotz Kontakt Gmbh Selbsttätiger Momentschalter.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3207877A (en) * 1959-03-02 1965-09-21 Satchwell Controls Ltd Thermostatic switch with permanent magnet induced snap action

Also Published As

Publication number Publication date
CH268298A (de) 1950-05-15
FR939614A (fr) 1948-11-19
NL72699C (ko)
GB606055A (en) 1948-08-05
BE470382A (ko)

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