US3010089A - Contactless snap-action limit switch - Google Patents

Contactless snap-action limit switch Download PDF

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Publication number
US3010089A
US3010089A US774672A US77467258A US3010089A US 3010089 A US3010089 A US 3010089A US 774672 A US774672 A US 774672A US 77467258 A US77467258 A US 77467258A US 3010089 A US3010089 A US 3010089A
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US
United States
Prior art keywords
magnet
shaft
disposed
limit switch
snap
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
US774672A
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English (en)
Inventor
Pierce Lawrence
Marshall P White
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
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
Priority to CA640670A priority Critical patent/CA640670A/en
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US774672A priority patent/US3010089A/en
Priority to JP3443859A priority patent/JPS361180B1/ja
Application granted granted Critical
Publication of US3010089A publication Critical patent/US3010089A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
    • G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
    • G01D5/2033—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils controlling the saturation of a magnetic circuit by means of a movable element, e.g. a magnet

Definitions

  • WlTNESSES @W RKG' ATTORNEY United States Patent This invention relates to limit switches and more particularly to limit switches utilizing contactless static magnetic elements.
  • One object of this invention is the provisionof movable and stationary magnetic elements for producing a pulse of magnetization in a magnetic circuit which is effective to produce a switching action in a circuit.
  • FIGURE 1 is a plan view, with the casing removed, of a limit switch embodying the invention
  • FIG. 2 is a longitudinal sectional. view of the showing made in'FlG. 1;
  • FIGS. 3, 4 and 5 show some elements in detail; and- FIG. 6 is a diagrammatic view of a basic circuit for a switching system with which the mechanical elements of this invention are used.
  • FIGS. 1 and 2 together showthe complete limit switch.
  • a molded assembly 12 carries. an encapsulated saturable reactor. The assembly is rigidly bolted to. the base 6.
  • FIG. 2 the cover 1 is shown in position.
  • the cover has the conduit opening at the left through which the leads are passchfor connection to the terminals 7. and 7 for.
  • shaft B The length of shaft B is slightly greater than the width of the pedestal P.
  • the magnet 2 is securely clamped to the left, end of the shaft B by means of the brass screw A.
  • Magnet 3 is similarly clamped on the right end of; shaft B by means of" brass screw E.
  • Screw E is somewhat elongated and has a shoulder at itsmid region with theregion to the right of the shoulder-being an enlarged cylindrical portion to form a bearing stud between the head ofthe screw and the shoulder for the brass beveled pinion 5 and;
  • the bracket 13 has the construction shown in FIG. 4 and thus. must rotate with shaft 19.
  • a lever-18 is adjustably secured to the lower end of the shaft 19.
  • the outer end of-the lever carries a roller which engages a suitable dog on. a movable part of a machine requiring a limit switch.
  • the magnet 4 is secured to the bracket 21 as shown in FIG. 3 and the back of the bracket, in the assembled relation, is brazed to the beveled pinion 5.
  • a non-magnetic stop 22, constructed as shown in FIG. 5, is boltedby means of a non-magnetic bolt to the base 6, as shown inFIG. 1. This. stop prevents the magnets 2 and 3 from rotating clockwisewhen viewed from, the left.
  • the springlti so biases the parts that the south pole of magnet 4, is, whenviewed from the-left, about 45 degrees in a counterclockwise direction from the vertical. Magnet 4 thus tends to rotate magnet 3 clockwise, but the stop 22 prevents such rotation. Magnets 2 and 3 are thus normally in avertical position with their north polesat the top.
  • This limit switch circuit comprises four rectifying elements D1, D2, D3 and D4, two resistors R1 and R2, and a contactless saturable reactor type limit switch comprism ing the switch assembly shown in FIGS. 1 and 2.
  • the switch among other elements comprises aperrnanent magnet 2 which is actuated by a quick action, as explained hereinabove to vary the saturation of the reactor core.
  • an alternating-current voltage of one phase, or instant polarity is applied to input terminal 113.
  • An alternating-current voltage of a different phase of opposite instantaneous polarity 6 is applied to input terminal 114.
  • An output terminal 130 may be con nected to a magnetic logic element of a control board. This logic element is set to select only 6 phase voltages.
  • An output terminal 14 may be connected to a magnetic logic element which is set to select only phase voltages. Both magnetic logic elements are connected to a common conductor C.
  • the resistor R1 is connected to a DC. voltage and resistor R2 is connected to a D.C. qb voltage.
  • the reactor has a high impedance which causes the 0 and outputs to go to zero.
  • the p input voltage is considered as being current flows through the rectifier D3 to provide a output of 13.
  • this output signal is of no importance since the logic element LE6 which it is feeding is set to select only 9 voltages.
  • the reactor magnetizing current is passed by the D2, R2, D.C. combination to hold the output at 14 at zero.
  • the positive side of DC. qb voltage is connected to the common conductor C.
  • the A.C. voltage is considered as being the A.C. 6 voltage is and current is prevented from flowing by the rectifier D4. Therefore, there is no 0 output signal at this time.
  • the reactor core is reset every half cycle. This is done first by one of the alternatingcurrent sources and then by the other. if the reactor core is not reset, the impedance would be small and the limit switch would be ineffective.
  • the switching system may be used to control magnetic logic elements and thus load units. With both 0 and 5 outputs, it is possible to drive or operate twice as many logic elements as was previously possible. Also, it is possible to separately operate the 0 and o logic elements.
  • a limit switch actuator in combination, a base, bearing means on the base, a shaft disposed for rotation in said bearing means, a crank-arm mechanically coupled to one end of said shaft, said crank-arm being biased to a given position on said base, a bevel gear connected to the other end of of said shaft, second bearing means on said base having a bearing axis normal to the axis of the shaft in the first mentioned bearing means, a shaft in the second bearing means, a bevel pinion disposed for rotation on one end of the second shaft and meshing with the bevel gear, a firs-t permanent magnet rigidly coupled to the bevel pinion and having its poles disposed on opposite sides of the second shaft, a second permanent magnet secured to the second shaft disposed for free rotation with the second shaft and being disposed in close proximity to the first permanent magnet and in facing relation thereto, stop means disposed on the base and positioned to limit the movement of the second magnet through an angle that is a fraction of one complete turn, said stop being so positioned that the repulsion
  • a limit switch actuator in combination, a base, bearing means on the base, a shaft disposed for rotation in said bearing means, a crank-arm mechanically coupled to one end of said shaft, said crank-arm being biased to a given position on said base, a bevel gear connected to the other end of said shaft, second bearing means on said base having a bearing axis normal to the axis of the shaft in the first mentioned bearing means,
  • a shaft in the second bearing means a bevel pinion disposed for rotation on one end of the second shaft and meshing with the bevel gear, a permanent magnet rigidly coupled to the bevel pinion and having its poles disposed on opposite sides of the second shaft, a second permanent magnet secured to the second shaft and disposed for free rotation with the second shaft and being disposed in close proximity to the first magnet and in facing relation thereto, stop means disposed on the base and positioned to limit the movement of the second magnet through an angle that is a fraction of one complete turn, said stop being so positioned that the repulsion 5 6 force of the like poles of the magnets, when the lever position causing a rapid change oi flux in said core to is in its biased position, forces the second magnet to one effect a switching operation.
  • a third magnet rigidly coupled to the second magnet but spaced from the Refetences Cited in the me of patent second magnet to be substantially unaffected by leakage 5 UNITED STATES PATENTS flux from the second magnet, a core composed of mag- 2,378,129 Chambers June 12, 1945 netic material, a coil disposed on the core, pole pieces at 2,414,688 Chambers Jan. 21, 1947 Opposite ends of the core, said third magnet when moved 2,471,947 Giannini May 31, 1949 by snap-action from its unactuated position to its actuated 2,856,591 White Oct. 14, 1958

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnets (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
US774672A 1958-11-18 1958-11-18 Contactless snap-action limit switch Expired - Lifetime US3010089A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CA640670A CA640670A (en) 1958-11-18 Contactless snap-action limit switch
US774672A US3010089A (en) 1958-11-18 1958-11-18 Contactless snap-action limit switch
JP3443859A JPS361180B1 (enrdf_load_stackoverflow) 1958-11-18 1959-11-05

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA640670T
US774672A US3010089A (en) 1958-11-18 1958-11-18 Contactless snap-action limit switch

Publications (1)

Publication Number Publication Date
US3010089A true US3010089A (en) 1961-11-21

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ID=72234597

Family Applications (1)

Application Number Title Priority Date Filing Date
US774672A Expired - Lifetime US3010089A (en) 1958-11-18 1958-11-18 Contactless snap-action limit switch

Country Status (3)

Country Link
US (1) US3010089A (enrdf_load_stackoverflow)
JP (1) JPS361180B1 (enrdf_load_stackoverflow)
CA (1) CA640670A (enrdf_load_stackoverflow)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2378129A (en) * 1941-08-07 1945-06-12 Trist & Co Ltd Ronald Magnetic device
US2414688A (en) * 1942-08-22 1947-01-21 Trist & Co Ltd Ronald Magnetic device
US2471947A (en) * 1945-06-04 1949-05-31 Howe & Fant Inc Impulse generator for telemetering systems
US2856591A (en) * 1956-08-15 1958-10-14 Westinghouse Electric Corp Switching devices

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2378129A (en) * 1941-08-07 1945-06-12 Trist & Co Ltd Ronald Magnetic device
US2414688A (en) * 1942-08-22 1947-01-21 Trist & Co Ltd Ronald Magnetic device
US2471947A (en) * 1945-06-04 1949-05-31 Howe & Fant Inc Impulse generator for telemetering systems
US2856591A (en) * 1956-08-15 1958-10-14 Westinghouse Electric Corp Switching devices

Also Published As

Publication number Publication date
CA640670A (en) 1962-05-01
JPS361180B1 (enrdf_load_stackoverflow) 1961-03-08

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