US2879355A - Snap action device - Google Patents

Snap action device Download PDF

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Publication number
US2879355A
US2879355A US664034A US66403457A US2879355A US 2879355 A US2879355 A US 2879355A US 664034 A US664034 A US 664034A US 66403457 A US66403457 A US 66403457A US 2879355 A US2879355 A US 2879355A
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US
United States
Prior art keywords
strip
vane
body section
contact
section
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
US664034A
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English (en)
Inventor
James W Welsh
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.)
HODA Corp
Original Assignee
HODA 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
Application filed by HODA CORP filed Critical HODA CORP
Priority to US664034A priority Critical patent/US2879355A/en
Priority to GB17221/58A priority patent/GB863041A/en
Priority to FR1207044D priority patent/FR1207044A/fr
Priority to DES58437A priority patent/DE1155185B/de
Application granted granted Critical
Publication of US2879355A publication Critical patent/US2879355A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H01H37/46—Thermally-sensitive members actuated due to expansion or contraction of a solid
    • H01H37/48—Thermally-sensitive members actuated due to expansion or contraction of a solid with extensible rigid rods or tubes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H61/00—Electrothermal relays
    • H01H61/06—Self-interrupters, i.e. with periodic or other repetitive opening and closing of contacts

Definitions

  • This invention relates to electric switches or circuit controllers using a snap action vane actuated by a thermostatic or thermodynamic opera-tor to control the operation of circuit controlling contacts. More particularly, the invention is directed to switches of this type in which the thermostatic operator is an integral or unitary part of the snap action vane.
  • the vane is pre-stressed to bend about the other diagonal by attaching a thermostatic wire or ribbon to the corners at the ends of the first diagonal, the wire or rib bon being attached in the cold, contracted condition with the vane bent about the second diagonal.
  • a thermostatic wire or ribbon to the corners at the ends of the first diagonal, the wire or rib bon being attached in the cold, contracted condition with the vane bent about the second diagonal.
  • a piece of preferably electrically conductive spring metal is used, the metal being selected for high elasticity and resistance to creep under static or dynamic stresses.
  • Other factors important in the selection of the metal are its specific temperature resistance, coefficient of electrical resistance, and coefiicient of expansion, all of which factors must be considered with paratent ticular reference to external or ambient operating conditions.
  • the metal piece is formed with a closed-end slot extending along and parallel to an edge so as to provide a narrow strip of metal along such edge integral at each end with the much larger main body section of the vane.
  • At least the main body section of the vane is then deformed into a shallow V-shape with the apex of the V extending perpendicularly to the narrow strip and preferably bisecting the latter.
  • Such deformation may be effected by providing or forming a narrow rectangular flat section along such apex, with the wings of the V extending at a small angle to such section.
  • a first contact secured on the undersurface of the strip at or immediately adjacent its mid-section is normally engaged with a second contact fixed relative to the vane mounting point, these two contacts forming part of an electric heating circuit including the vane.
  • this circuit is closed, with resultant heating of the vane due to electric current flow therethrough and consequent expansion of the integral strip as explained above, the second contact resists or prevents lowering of the strip relative to the vane mounting point.
  • the contact pressure is maintained and even increased during the heating cycle right up to the instant the strip snaps to the upwardly bowed position disengaging the contacts and opening the heating circuit.
  • This maintenance of the contact pressure in combination with the snap opening of the contacts, greatly prolongs the contact life. Such prolongation of contact life is enhanced by the snap re-closing of the contacts.
  • the vane may have any desired shape in plan, such as a square, a rectangle, a circle, or a semicircle, dependent upon the desired parameters and intended use of the switch.
  • Figs. 1, 2 and 3 are plan views of three pieces of metal slotted to form snap action vanes in accordance with the invention but before deformation of the main body into a shallow V-shape;
  • Fig. 4 is a plan view of the vane of Fig. 1 after deformation of the main body of the vane;
  • Fig. 5 is a side elevation view of the vane of Fig. 4, the V-shape of the main body being exaggerated;
  • Fig. 6 is a bottom plan view of the vane attached to a mounting bracket carrying, in insulated relation, a contact engageable with a contact on the undersurface of the strip;
  • Fig. 7 is a front elevation view of an automotive type flasher unit embodying the vane of Figs. 1 and 4, the circuit controlled thereby being schematically illustrated;
  • Fig. 8 is a side elevation view of the flasher unit.
  • Fig. 9 is a view similar to Fig. 7 showing the flasher contacts open.
  • a vane 15, in accordance with the invention may be formed by taking a rectangular piece of thin, relatively stifi, resilient metal and forming a. closed-end slot 16 along one edge so as to divide the vane into a relatively narrow thermostatic operator strip 20 integral at each end with a main body section 21.
  • the metal preferably has highelectrical resistance.
  • vane shape is dictated by external parameters.
  • a circular or semicircular shape such as the vane 15' of Fig. 2 or the vane 15" of Fig. 3 is desirable. Vanes of circular or semi-circular shape may be useful, for example, as circuit breakers installed in lamp sockets. In some other instances, a square shape or an, arcuate shape may be preferred.
  • the cutting of the slot 16 (16', 16") provides a narrow thermostatic operator strip 20 (20', 20") along an edge of the vane and separated by the slot from the main body section 21 (21', 21") of the vane.
  • This strip which is integral with the main body section at each end 17 (17, 17"), has a cross-sectional area only a fraction of that of the main section, and acts as the usual resistance wire or strip hitherto separate from and mechanically attached to the vane along a diagonal.
  • the vane preferably including strip 20
  • the vane is given a shallow V-shape with the apex 22 of the V extending normal to strip 20 and preferably bisecting the latter. This may be efiectively accomplished by providing a rectangular flat section 23 along the apex of the V as shown in Fig. 4.
  • the angle of the V in section 21 is greater than any angle of the V in strip 20.
  • body section 21 For effective action of vane 15 as a snap action switch, body section 21 must be secured or supported at a fixed point on or immediately adjacent the apex of the V. Referring to Fig. 6, this is accomplished, in practice, by spot welding or brazing section 21 to one end 31 of an electrically conductive bracket 30 having a center section 32 ofi'set vertically from end 31 and extending beneath strip 20. Bracket 30 has an outer end 33 offset vertically from mid-section 32. Mid-section 32 has a band 34 of dielectric material therearound, and astrip 36 of conductive material is wound about band 34 and carries a contact 35 normally engaged with a contact 25 on the undersurface of strip 30.
  • the vane and bracket combination 15-30 is mounted on a dielectric base 40 carrying receptacle engaging prongs 41, 42, as shown in Figs. 7-9.
  • the outer end 33 of bracket 30 is welded, brazed, or soldered to a rivet securing prong 41 to base 40
  • the outer end of conductor 36 is welded, brazed or soldered to a rivet securing prong 42 to base 40.
  • the mechanics of assembly are such that strip 20 has a shallow V-shape'and firmly presses its contact 25 against the contact 35 mounted in insulated relation on the mid-section 32 of bracket 30.
  • agrounded battery 43 which may be an automotive battery, is connected through a switch 45 to a receptacle (not shown) in which prong 41 is engaged.
  • Prong 42 is engaged in a receptacle (not shown) connected to a grounded load such as lamps 44.
  • switch 45 When switch 45 is closed, current will flow from battery 43 to prong 41, bracket 30, and vane 15.
  • the current in vane 15 flows over two parallel paths to the opposite ends of strip 20, through the strip and closed contacts 25, 35 and thence into strip 36, from whence the circuit is completed through prong .42 and lamps 44 to ground.
  • strip 20 has a cross-section much less than that of body section 21, it is heated much more rapidly than the 4 body section, when the heating circuit is completed by closing switch 45. Consequently strip 20 expands longitudinally relative to body "section 21. As strip 20 expands, it is restrained at its ends by the V-shape body 21, so that the center of strip 20 is forced downwardly to increase the pressure of contact 25 against fixed contact 35. The continued expansion of strip 20, with downward movement of the strip thus-restrained, results in a straightening force being exerted on body section 21.
  • a snap action vane comprising a substantially flat piece of a single resilient metal having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a-strip-separatedfrom said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; whereby, upon cyclic heating and cooling of said strip the latter will cyclically expand and contract-relative to the body section and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially, relative to the body section, out of co-planar relation with the latter; an electric heating circuit for said stripincluding said strip;.afixed support secured to said body section;- a first contact fixed relative to said support; and a second contact carried by said strip and movable into and .out of engagement with said first contact by such relative movement of said strip.
  • a snap action vane comprising a substantially flat piece of a single resilient metal of relatively high electrical resistance having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end,
  • a snap action vane comprising a substantially fiat piece of a single resilient metal having a single relatively elongated closed-end slot extending along and adjacent one edge thereof to divide the vane into a main body ection and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V; whereby, upon heating of said strip the latter will expand relative to the body section and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section.
  • a snap action vane comprising a substantially fiat piece of a single resilient metal having a single relatively elongated closed-end slot extending along and adjacent one edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V having an apex extending normal to said strip; whereby, upon heating of said strip the latter will expand relative to the body section and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section.
  • a snap action vane comprising a substantially flat piece of a single resilient metal having a single relatively elongated closed-end slot extending along and adjacent one edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area onlya fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V having an apex extending normal to said strip and substantially bisecting said strip; whereby, upon heating of said strip the latter will expand relative to the body section and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section.
  • a snap action vane comprising a substantially flat piece of a single resilient metal having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V; whereby, upon cyclic heating and cooling of said strip the latter will cyclically expand and contract relative to the body section and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section; a fixed support secured to said body section substantially at the apex of the V; a fixed support secured to said body section; a first contact fixed relative to said support; and a second contact carried by said strip and movable into and out of engagement with said first contact by such relative movement of said strip.
  • a snap action vane comprising a substantially flat piece of a single resilient metal of relatively high electrical resistance having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V; whereby, upon flow of electric current through the strip, the strip will heat and expand relatively to the body section and will cool and contract relative to the body section when the current flow is interrupted and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially rela' tive to the body section; a fixed support secured to said body section substantially at the apex of the V; a first contact fixed relative to said support; a second contact carried by said strip and moveable into and out of engagement with said first contact by such relative movement of said
  • a snap action vane comprising a substantially flat piece of a single resilient metal of relatively high electrical resistance having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V having an apex extending normal to said strip; whereby, upon flow of electric current through the strip, the strip will heat and expand relatively to the body section and will cool and contract relative to the body section when the current flow is interrupted and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section; a fixed support secured to said body section substantially at the apex of the V; a first contact fixed relative to said support; a second contact carried by said strip and moveable into and out of engagement with said
  • a snap action vane comprising a substantially flat piece of a single resilient metal of relatively high electrical resistance having a relatively elongated closed-end slot extending along and adjacent an edge thereof to divide the vane into a main body section and a strip separated from said body section by said slot and integral with the body section at each end, with the strip having a cross-sectional area only a fraction of that of the body section; at least the main body section of said vane being bent to form a shallow V having an apex extending normal to said strip and substantially bisecting said strip; whereby, upon flow of electric current through the strip, the strip will heat and expand relatively to the body section and will cool and contract relative to the body section when the current flow is interrupted and, due to the reaction of the body section on the ends of the strip, the intermediate portion of the strip will move substantially relative to the body section; a fixed support secured to said body section substantially at the apex of the V; a first contact fixed relative to said support; a second contact carried by said strip and move

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  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Thermally Actuated Switches (AREA)
  • Push-Button Switches (AREA)
US664034A 1957-06-06 1957-06-06 Snap action device Expired - Lifetime US2879355A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US664034A US2879355A (en) 1957-06-06 1957-06-06 Snap action device
GB17221/58A GB863041A (en) 1957-06-06 1958-05-29 Improvements in electric snap action switch device
FR1207044D FR1207044A (fr) 1957-06-06 1958-05-30 Perfectionnements aux dispositifs à action brusque
DES58437A DE1155185B (de) 1957-06-06 1958-05-30 Thermisches, strombeheiztes Schnappglied mit Dehnstreifen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US664034A US2879355A (en) 1957-06-06 1957-06-06 Snap action device

Publications (1)

Publication Number Publication Date
US2879355A true US2879355A (en) 1959-03-24

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ID=24664240

Family Applications (1)

Application Number Title Priority Date Filing Date
US664034A Expired - Lifetime US2879355A (en) 1957-06-06 1957-06-06 Snap action device

Country Status (4)

Country Link
US (1) US2879355A (de)
DE (1) DE1155185B (de)
FR (1) FR1207044A (de)
GB (1) GB863041A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031551A (en) * 1958-07-02 1962-04-24 Texas Instruments Inc Electrical switch structures
US3090851A (en) * 1959-07-08 1963-05-21 Ideal Corp Flasher switch
US3131274A (en) * 1961-01-25 1964-04-28 Schmidinger Joseph Pull means for hot wire flashers or the like

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2363280A (en) * 1941-05-14 1944-11-21 Westinghouse Electric & Mfg Co Circuit controller
US2425717A (en) * 1942-06-25 1947-08-19 F A Smith Mfg Company Thermostatic switch assembly
US2533274A (en) * 1944-11-28 1950-12-12 Fasco Industries Bimetallic thermostatic element
US2708697A (en) * 1953-08-18 1955-05-17 Signal Stat Corp Snap-action device
US2716682A (en) * 1953-09-02 1955-08-30 Gen Mills Inc Positive opening and closing switch with wiping action
US2720568A (en) * 1953-01-27 1955-10-11 Stevens Mfg Co Inc Snap-acting bimetallic thermostat
US2825960A (en) * 1955-07-14 1958-03-11 M J Mccarthy Snap-acting element and method of making same
US2834853A (en) * 1957-04-12 1958-05-13 Essex Wire Corp Snap-acting bimetal device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2177671A (en) * 1937-04-30 1939-10-31 Schmidinger Joseph Thermal switch and the like
USRE24023E (en) * 1951-07-21 1955-06-14 Schmidinger

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2363280A (en) * 1941-05-14 1944-11-21 Westinghouse Electric & Mfg Co Circuit controller
US2425717A (en) * 1942-06-25 1947-08-19 F A Smith Mfg Company Thermostatic switch assembly
US2533274A (en) * 1944-11-28 1950-12-12 Fasco Industries Bimetallic thermostatic element
US2720568A (en) * 1953-01-27 1955-10-11 Stevens Mfg Co Inc Snap-acting bimetallic thermostat
US2708697A (en) * 1953-08-18 1955-05-17 Signal Stat Corp Snap-action device
US2716682A (en) * 1953-09-02 1955-08-30 Gen Mills Inc Positive opening and closing switch with wiping action
US2825960A (en) * 1955-07-14 1958-03-11 M J Mccarthy Snap-acting element and method of making same
US2834853A (en) * 1957-04-12 1958-05-13 Essex Wire Corp Snap-acting bimetal device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3031551A (en) * 1958-07-02 1962-04-24 Texas Instruments Inc Electrical switch structures
US3090851A (en) * 1959-07-08 1963-05-21 Ideal Corp Flasher switch
US3131274A (en) * 1961-01-25 1964-04-28 Schmidinger Joseph Pull means for hot wire flashers or the like

Also Published As

Publication number Publication date
FR1207044A (fr) 1960-02-12
GB863041A (en) 1961-03-15
DE1155185B (de) 1963-10-03

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