US3593236A - Magnetic switch - Google Patents

Magnetic switch Download PDF

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Publication number
US3593236A
US3593236A US21606A US3593236DA US3593236A US 3593236 A US3593236 A US 3593236A US 21606 A US21606 A US 21606A US 3593236D A US3593236D A US 3593236DA US 3593236 A US3593236 A US 3593236A
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United States
Prior art keywords
blade means
stop
fixed
arm
blade
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
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US21606A
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English (en)
Inventor
Roland D Beck
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.)
TDK Micronas GmbH
ITT Inc
Original Assignee
Deutsche ITT Industries GmbH
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Publication of US3593236A publication Critical patent/US3593236A/en
Assigned to ITT CORPORATION reassignment ITT CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION
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
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/52—Thermally-sensitive members actuated due to deflection of bimetallic element
    • H01H37/56—Thermally-sensitive members actuated due to deflection of bimetallic element having spirally wound or helically wound bimetallic element
    • 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

Definitions

  • a set of switch points are enclosed within a glass structure and include an armature that is magnetically movable to effect different connection arrangements of the switch points.
  • a first magnet when acting alone attracts the armature to provide a first connective arrangement.
  • a second magnet carried by a heat responsive bimetal is movable thereby to a position where its attractive influence on the armature overcomes that of the first magnet and transfers the points to a different connective arrangement.
  • An alternative embodiment has the two magnets mounted for unitary movement, that is, as the one magnet is moved into attractive influence, the other magnet is moved away, and vice versa.
  • This invention relates to highly reliable switches such as thermostat switches having a highly suitable differential and a low contact bounce.
  • a switch has been employed having a pole and a contact with a ferromagnetic armature fixed to the pole.
  • a first permanent magnet is fixed and biases the pole in one direction.
  • a second permanent magnet is movable toward and away from the armature on one side thereof opposite the side on which the fixed magnet is positioned.
  • the pole is moved away from the fixed magnet when the movable magnet moves close enough, and vice versa.
  • the fixed magnet may be adjusted in position to adjust contact pressure. Therefore, this overcomes the prior art problem where it was impossible to adjust contact pressure.
  • the quiescent pressure which is established between the switch pole and the contact spaced farthest way from the movable magnet is extremely critical.
  • the pressure must fall within a narrow range to insure good electrical conductivity and a small differential when a bimetal carries the movable magnet. From the instant that the contact next to the fixed magnet opens the differential is the temperature change required to the instant the same contact closes.
  • the use of the fixed magnet makes it possible to adjust contact pressure within the said narrow range because, although it is fixed, it can be adjusted to its correct, fixed position before use.
  • a flexible leaf spring pole stop is employed to prevent contact bounce.
  • the rubbing action of the contacts and the flexure losses act as a dashpot to absorb the kinetic energy of the moving pole over a greater length of time because the spring is relatively weak and allows energy exchange over a long period before any bounce can occur. That is, the kinetic energy absorption can take place as the leaf spring stop and pole rock back and forth without the contacts separating. Thus the stop and pole contacts may rub together instead of separating as the two leaf springs rock.
  • FIG. I is a perspective, diagrammatic, elevational view of the invention in one of its connective conditions
  • FIG. 2 is a view similar to that of FIG. I with the switch shown in another connective condition;
  • FIG. 3 is an enlarged, sectional view of that portion of the invention included within the glass enclosure
  • FIG. 4 is a sectional view taken along the Iine4-4 shown in FIG. 3;
  • FIG. Si is a diagrammatic view of special magnetic actuating means
  • FIGS. 6 and 7 depict a further embodiment of the invention.
  • FIG. 8 is a side elevational view of still another embodiment of the invention.
  • FIG. 9 is a top plan view of a bracket shown in FIG. 8.
  • a switch 10 of the present invention includes a spiral, heat responsive bimetal 11, a first magnet means 12 carried by member 11, an enclosed set of switch points 13, and a second magnet means 14 all mounted in a casing 15.
  • the enclosed set of switch points 13 includes first and second conducting blades 16 and 17 of a nonmagnetic, springlike material, which are provided adjacent an end thereof with respective contact points 18 and 19.
  • the blades are mounted within a sealed glass envelope 20 so that the contact points are in a facing, directly opposed relation to one another.
  • A. somewhat longer armature blade 21 of flexible, springlike conductive material when assembled is disposed between blades 16 and I7 but insulated therefrom.
  • a contact point 22 is provided on the armature and has opposite facing surfaces such that lateral movement of the armature produces contact with either of contact points 18 or 19, as the case may be.
  • the end of the armature extending beyond the ends of blades 16 and 17 is provided with a body of magnetic material 23.
  • Blades I6 and I7 and armature blade 21 are included within an hermetically sealed, elongated, tubular glass envelope 20 containing a nonreactive gas such as a hydrogennitrogen mixture, for example. External electrical connection to the switch points and armature is provided via leads 25, 26, and 27 extending from one end of the envelope.
  • the armature and contact blades are so constructed that in the unactuated position, i.e., neither magnet in influential position, the armature will lie between the two blades; and contact point 22 will be free from contact with either of points 18 or 19.
  • a second magnet means 14 is mounted from casing 15 to have an extended surface in contact with the glass envelope and lies directly opposite the flat side of magnetic body 23 of the armature.
  • the magnetic field setup by magnet 1t attracts the armature a sufficient amount to close the circuit between contact point 22 on the armature and point 19 on blade I7.
  • the flexible, springlilte quality of both blade 17 and the armature are chosen to provide a firm contacting relation and achieve "overtravel" of the armature about which further details will be given later.
  • the contact pressure in this biased direction may be easily adjusted by moving the fixed magnet relative to the envelope or vice versa.
  • spiral bimetal member ll begins to coil producing a potential force therein which acts against the attractive influence of magnet means [2 for the armature blade 2]. This coiling continues until a point is reached at which the restoring force of the bimetal spiral is great enough to overcome the magnetic attractive force, and the first magnet means is moved away from glass envelope and beyond the critical limit of magnetic influence.
  • second magnet means 14 now acts solely on the armature blade and causes rapid transfer of the contacting condition to that shown in FIG. 1.
  • the body of magnetic material 23 is unsymmetrically arranged at the end of armature blade 2i. That is, a relatively longer portion 28 of magnetic material is on the side of the blade facing first magnet means 12 than the corresponding portion 29 facing second magnet means 14.
  • This unsymmetrical character of magnetic body 23 has a remarkable and beneficial effect upon operation. ln explanation and beginning with the device disposed as in FIG. 1, when magnet means 12 moves toward glass envelope 20, the mutual attractive influence between means 12 and magnetic portion 28 increases to the point where blade 2
  • begins to flex below point 22 and continues flexing until the points 22 and 18 are closed.
  • blade 2! beyond point 22 does not flex as much as it did when in the other closed state due to the additional length of portion 28.
  • the spacing of magnet means 12 and body 23 is less when points 18 and 22 are closed than is the spacing of the body and means 14 when contacts 22 and 19 are closed.
  • FIGS. 3 and 4 there is shown the detailed aspects of contact blades 16 and 17 and armature blade 2! as they are assembled within the enclosure.
  • Blades 16 and 17 are bent at their approximate midpoint so that when oriented with points l8 and I9 facing, the space between the blade portions is greater at this end than at the mounting end.
  • insulation sheets 30 and 31 are situated between blades 16, 2] and I7, 21, respectively.
  • An alignment opening 32 is formed in each of the blades and the insulation sheets for receiving an insulating and alignment plug 33.
  • insulating sheet 3! is protectively wrapped around the long edges of the blades to permit edge portions of blade l7 to engage securingly the edges of the assembly, making an integral structure.
  • Blades l6, l7, and 2 Proper relative flexibility of blades l6, l7, and 2] is important to overall operation. if the blades are too rigid, the contacts will tend to bounce and produce welding. On the other hand, if the blades are too soft, sensitivity of transfer is adversely affected. It has been found, for example, that when the blades are constructed of the same material and of the same width, blades I6 and 17 should have a thickness that is at least twice that of the armature blade 21, but not exceed three times the armature thickness for best results. In actual constructions of phosphor-bronze, with the armature blade having a thickness of 0.004 inches, blades 16 and 17 of the same material were too flexible at 0.007 inches and too rigid at 0.0[5 inches in thickness.
  • FIG. 5 depicts a special magnet particularly advantageous for use as magnet means l2.
  • the magnet includes a front magnetic layer 34 of polar arrangement as shown and a back magnetic layer 35 of polar arrangement opposite to that of 34.
  • the back layer 35 is secured and in flush contacting relation to a plate 36 of magnetically influenceabli: material.
  • Plate 36 is one plate of bimetal member II. It has been found that the attractive force of the magnet means 12 is enhanced to a con siderable degree by this structural arrangement.
  • a heat responsive magnetically actuable switch requiring a relatively small mass of bimetal to act as the prime mover and yet sufficient force is provided through magnetic means to exert sufficient pressure on the switch points so that substantial currents can be accommodated.
  • FIGS. 6 and 7 An alternative form of the invention is depicted in FIGS. 6 and 7 in which a pair of magnet means are swung as a unit to produce switching action.
  • the basic switch assembly comprising blades 16 and 17 and armature blade 21, enclosed within envelope 20, is identical to that already described; and for that same reason, the same reference numerals are used.
  • a magnet means 37 is secured to one extremity of bimetal 1! to face the envelope.
  • a U-shaped support bracket 39 has the end of one leg secured to the bimetal on the side opposite where magnet means 37 is mounted and thereby disposing the other leg on the other side of envelope 20. Bracket 39 could be eliminated with its function being carried out by an extension of the bimetal.
  • At the extremity of the other leg of member 39 there is secured a further magnet means 38 generally facing the envelope.
  • the magnet means are so mounted and bracket 39 so dimensioned that when located at the extreme right position as in FIG. 6, magnet means 37 contacts the outer surface of the envelope; and magnet means 38 is disposed beyond its range of magnetic effectivity. Further, when the bracket is transferred to its extreme left position,
  • magnet means 38 contacts the envelope; and magnet means 37 is spaced therefrom.
  • a further possible modification would be to make body 23 symmetrical with both halves or parts of equal extent. This would result in a certain loss in sensitivity and perhaps an increase in bimetal volume. However, there would be a manufacturing advantage here since the armature, being of symmetrical construction, would be easier to fabricate.
  • magnets 37 and 38 are hereby defined to include both, (I) magnets, the position of which cannot be adjusted relative to each other, and (2) magnets, the position of which can be adjusted relative to each other.
  • FIG. 8 a somewhat different version of the embodiment of FIGS. 6 and 7 is shown.
  • a rigid bar 39 is fixed to a bimetal strip ll Brackets BI and B2 are fixed to bar 39'.
  • Brackets B1 and B2 have slotted horizontal portions P1 and P2.
  • Screws S1 and S2 are threaded into permanent magnets 37 and 38.
  • a slot L1 in bracket portion PI is shown in FIG. 9.
  • screw SI has a head H1 which is larger than the width of slot Ll.
  • Screws S1 and 52 may, thus, be tightened to hold magnets 37 and 38 rigid with brackets BI and B2, respectively.
  • screws SI and S2 When screws SI and S2 are loosened, they may be moved longitudinally in the bracket slots and retightened.
  • the positions of magnets 37' and 38' thus, are adjustable and movable relative to bar 39' for calibration, although they are both fixed relative to bar 39 during operation.
  • blades 16 and I7 have such flexibility that they themselves have a travel which is about equal to one-third that of blade 2].
  • the fixed magnet 14 may, in calibration, be moved to adjust the pres sure of contacts 19 and 22 to within an extremely small critical range for good electrical conductivity and small operating force.
  • blades 16 and I7 act as weak springs (see the large deflection of blade 16 in FIGS. 2 and '7, and the large deflection of blade 17 in FIG. 6) makes it possible to reduce bounce of contact 22 on contacts 18 and I9 to an extraordinary degree.
  • a switch comprising:
  • a pole including a first nonmagnetic cantilever leaf spring
  • said pole including a ferromagnetic armature fixed to said first spring near the free end thereof, said pole having a contact on each side thereof at substantially the same position along the length thereof;
  • a second and third nonmagnetic cantilever leaf spring fixed at one end relative to said first spring on opposite sides of said pole, said second and third springs each having a contact to be engaged by a respective one of said pole contacts;
  • magnetic means including two movable permanent magnets to shift said pole contacts alternately into engagement with said second and third spring contacts, said permanent magnets being fixed in position relative to each other; and means for mounting said magnets on said base in a position outside said envelope to move alternately toward and away from the self same envelope from positions on opposite sides thereof, respectively.
  • mag netic means includes a support fixed to said base, said two permanent magnets being fixed to said support, said magnets being movable toward and away from respective opposite sides of said armature, said magnets being of equal polar strengths.
  • a switch magnetically actuable by magnetic flux externally applied along a predetermined path comprising:
  • first flexible blade means including a contact point
  • second flexible blade means including a contact point and a magnetically influenceable body
  • a switch magnetically actuable by magnetic flux externally applied along a predetermined path comprising:
  • first flexible blade means including a contact point
  • second flexible blade means including a contact point and a magnetically influenceable body
  • a third flexible blade means being secured together with the first and second blade means only on the opposite side of the second blade means at which the first blade means is disposed, said third blade means having a contact point that is in registry with the contact point of the second blade means, said first, second, and third blade means and respective points forming a single-pole, double-throw switch with connective condition depending upon the direction of applied attractive magnetic flux, said securing means including edge portions of the first blade means overlappingly clamped about edge portions of the second and third blade means, and insulation means inserted between the blade means and between the clamped edges and the blade means.
  • a switch comprising:
  • a pole having one movable end and another end fixed relative to said base;
  • a stop having a conductive portion engageable by said pole conductive portion, said stop having an end fixed relative to said base;
  • magnetic means including two permanent magnets movable to shift said pole alternately toward and away from said stop;
  • said actuation means includes a substantially rigid member, said magnets being attached to said member.
  • said actuation means includes means to support said magnets in a predetermined, spaced relation to each other.
  • said actuation means includes a member, and first and second means to hold said magnets, respectively, in fixed positions relative to said member,
  • a switch magnetically actuable by magnetic flux exter nally applied along a predetermined path comprising:
  • first flexible blade means including a contact point
  • second flexible blade means including a contact point and a magnetically-influenceable body
  • said magnetic body being located adjacent the free end of the cantilever-mounted second blade means
  • the second blade means being substantially more flexible than the first blade means whereby on application of attractive magnetic flux in a first direction along the predetermined path, the second blade means is moved toward the first blade means bringing the respective points into contact and the magnetic body continuing in the same direction a slight amount after the point contact, and on application of attractive magnetic flux along the other direction of the predetermined path, the magnetic body is moved a slight amount and portions of the second blade means between the contact and the magnetic body are flexed before the contact points separate, said second blade means having a fixed end and a free end, said contact point on said second blade means being located between said fixed end and said free end, said magnetic body being located between said contact point on said second blade means and said free end, said movement of said second blade means causing flexure thereof about said first blade means contact point as a center, and also about said fixed end as a center with said first blade means also flexing during both of said flexures of said second blade means, said blade means being constructed of differing thicknesses of the same material, the thickness of the first blade means being not
  • a switch comprising: a base; a sealed envelope fixed to said base; a moving contact arm located inside said envelope, said arm including a cantilever leaf spring having one movable end and one end fixed relative to said envelope; a magnetic armature fixed to said arm spring at a position spaced from said fixed end thereof; a first stop fixed relative to said envelope inside thereof; said arm spring movable end being movable back and forth in first and second directions, said arm spring being movable in said first direction into engagement with said first stop; a first permanent magnet fixed relative to said envelope outside thereof on one side thereof spaced in said first direction from said arm; an actuation device mounted on said base outside said envelope; and a second permanent magnet fixed to said device, said device being actuable to move said second magnet toward and away from said arm and said envelope in said first and second directions, respectively, said second magnet being adapted to produce a torque on said arm of a magnitude large enough to attract said armature away from under the influence of said first magnet and to pull said arm out of engagement with said stop when said second
  • said first stop includes a cantilever leaf spring located inside said envelope, said first stop spring having a movable end and an end fixed relative to said envelope, said first stop being sufficiently flexible that it will move a substantial distance when engaged by said arm.
  • the other of said stops also has a conductive portion, said arm also having another conductive portion to engage said other stop conductive portion when said arm engages said other stop, said second stop also including a cantilever leaf spring located inside said envelope. said second stop spring having a movable end and an end fixed relative to said envelope. said second stop being sufficiently flexible that it will move a substantial distance when engaged by said arm, said stop conductive portions being spaced from the fixed ends thereof, respectively.
  • said stop includes a cantilever leaf spring located inside said envelope, said first stop spring having a movable end and an end fixed relative to said envelope, said first stop being sufficiently flexible that it will move a substantial distance when engaged by said arm.
  • said first stop has a conductive portion spaced from the fixed end thereof; said arm having a conductive portion spaced from the fixed end thereof and positioned to engage said first stop conductive portion when said arm engages said first stop.

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
US21606A 1970-03-23 1970-03-23 Magnetic switch Expired - Lifetime US3593236A (en)

Applications Claiming Priority (1)

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US2160670A 1970-03-23 1970-03-23

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US3593236A true US3593236A (en) 1971-07-13

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US21606A Expired - Lifetime US3593236A (en) 1970-03-23 1970-03-23 Magnetic switch

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US (1) US3593236A (cs)
BE (1) BE764598A (cs)
FR (1) FR2085004A6 (cs)
GB (1) GB1273935A (cs)
NL (1) NL7103851A (cs)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5216573U (cs) * 1975-07-24 1977-02-05
US4211991A (en) * 1977-05-25 1980-07-08 Regie Nationale Des Usines Renault Magnet-controlled switch
US4513271A (en) * 1982-07-16 1985-04-23 Minnesota Mining And Manufacturing Company Momentary contact magnetic switch
US6707371B1 (en) 2002-08-26 2004-03-16 Honeywell International Inc. Magnetic actuation of a switching device
US6720852B2 (en) 2002-08-26 2004-04-13 Honeywell International Inc. Methods and apparatus for actuating and deactuating a switching device using magnets
US6741158B2 (en) 2002-07-18 2004-05-25 Honeywell International Inc. Magnetically sensed thermostat control

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2121607A (en) * 1935-02-16 1938-06-21 Oran T Mciivaine Oscillator
US2240847A (en) * 1938-08-11 1941-05-06 Milwaukee Gas Specialty Co Magnetic switch
US2555571A (en) * 1948-06-11 1951-06-05 Allen E Chisholm Magnet operated switch
US3068333A (en) * 1960-09-08 1962-12-11 Robertshaw Fulton Controls Co Control device
US3325756A (en) * 1965-11-08 1967-06-13 Palmer M Maxwell Remotely controlled magnetic electric switch
US3331928A (en) * 1964-10-20 1967-07-18 Blaser Hans Ignition distributor contact-breaker for an internal combustion engine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2121607A (en) * 1935-02-16 1938-06-21 Oran T Mciivaine Oscillator
US2240847A (en) * 1938-08-11 1941-05-06 Milwaukee Gas Specialty Co Magnetic switch
US2555571A (en) * 1948-06-11 1951-06-05 Allen E Chisholm Magnet operated switch
US3068333A (en) * 1960-09-08 1962-12-11 Robertshaw Fulton Controls Co Control device
US3331928A (en) * 1964-10-20 1967-07-18 Blaser Hans Ignition distributor contact-breaker for an internal combustion engine
US3325756A (en) * 1965-11-08 1967-06-13 Palmer M Maxwell Remotely controlled magnetic electric switch

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5216573U (cs) * 1975-07-24 1977-02-05
US4211991A (en) * 1977-05-25 1980-07-08 Regie Nationale Des Usines Renault Magnet-controlled switch
US4513271A (en) * 1982-07-16 1985-04-23 Minnesota Mining And Manufacturing Company Momentary contact magnetic switch
US6741158B2 (en) 2002-07-18 2004-05-25 Honeywell International Inc. Magnetically sensed thermostat control
US6707371B1 (en) 2002-08-26 2004-03-16 Honeywell International Inc. Magnetic actuation of a switching device
US6720852B2 (en) 2002-08-26 2004-04-13 Honeywell International Inc. Methods and apparatus for actuating and deactuating a switching device using magnets
US20040217833A1 (en) * 2002-08-26 2004-11-04 Ableitner Jason L. Magnetic actuation of a switching device
US7026898B2 (en) 2002-08-26 2006-04-11 Honeywell International Inc. Magnetic actuation of a switching device

Also Published As

Publication number Publication date
NL7103851A (cs) 1971-09-27
GB1273935A (en) 1972-05-10
FR2085004A6 (cs) 1971-12-17
BE764598A (fr) 1971-09-22

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Owner name: ITT CORPORATION

Free format text: CHANGE OF NAME;ASSIGNOR:INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION;REEL/FRAME:004389/0606

Effective date: 19831122