US3656081A - Electric switch with a snap-action system - Google Patents

Electric switch with a snap-action system Download PDF

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Publication number
US3656081A
US3656081A US3065A US3656081DA US3656081A US 3656081 A US3656081 A US 3656081A US 3065 A US3065 A US 3065A US 3656081D A US3656081D A US 3656081DA US 3656081 A US3656081 A US 3656081A
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US
United States
Prior art keywords
contact
movable
actuating element
spring
snap
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Expired - Lifetime
Application number
US3065A
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English (en)
Inventor
Claus John
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Danfoss AS
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Danfoss AS
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Publication date
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Publication of US3656081A publication Critical patent/US3656081A/en
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    • 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
    • H01H5/04—Energy stored by deformation of elastic members
    • H01H5/18—Energy stored by deformation of elastic members by flexing of blade springs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/12—Means for adjustment of "on" or "off" operating temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/60—Means for producing snap action

Definitions

  • ABSTRACT [52] U.S. Cl. ..337/346, 200/67 D, 33ig77ll33t7g, A snap action thermostatic switch assembly ohm type having a bimetal arm and an omega spring.
  • the assembly has a fixed figs 6.7 8 i gfgygg figg contact and a pair of resiliently'mounted movable contacts on 337/342 346 347 5 59 1 opposite sides of the fixed contact.
  • the movablecontacts have 3 1 lugs and the bimetal arm has an actuating element which engages these lugs to move one contact or the other away from the fixed contact.
  • the bimetal arm has a displacement range [56] References Cited so that the actuating element thereof separates from the con- UNITED STATES PATENTS tact lug of a movable contact that is brought into engagement with the fixed contact. W1th this construction the tendency of Knapp X a movable ontact to rebound is reason of the 3,290,629 12/1966 Jeanne X mass associated with a movable contact being reduced the in- L t 3 1; g: stant the movable contact touches the fixed contact. 1n ous 2,833,893 5/1958 Weber ..337/343 1 Claims, 3 Drawing Figures PATENTEDAPR1 1 I972 SHEET 2 OF 2 Fig. 3
  • the invention relates to an electric switch with an electric contact system and a two-part snap-action system comprising a main arm and an omega spring.
  • An evaporator thermostat having a two-part snap-action a main am and an omega spring which snaps over on one side of the dead-center plane between positions defined by stops.
  • the contact system comprises a fixed contact and a moving contact which is pressed against the fixed contact by a closing spring.
  • the main arm carries an actuating element by which the moving contact is either raised or moved towards the fixed contact during the snap-over action.
  • the tension in the omega spring for which purpose the fixed bearing of this spring takes the form of an adjusting screw.
  • snap-action systems comprising more than two elements e.g. two rigid arms and a snap-action spring, which move through the dea -center plane during the snap- .over movement, the two end positions being defined by stops,
  • At least one of which is adjustable so as to vary the distance in the snap-action system.
  • the object of the invention is to provide an electric snap-action switch of the simplest possible construction, in which the tendency to rebound can be kept at a minimum.
  • the invention solves this problem by a combination of the following features:
  • the contact system comprises a movable contact, which is pressed by a closing spring against a fixed contact and can be lifted from the fixed contact by an actuating element on the main arm, the movable mass of the snap-action system being separated from the mass of the movable contact at the moment of closing.
  • the difference in the snap-action system is determined by two stops which determine the displacement of the main arm during the snap-over action and one at least of which is adjustable.
  • the distance between the two points at which the omega spring is supported is adjustable in order to set a minimum for rebound when contact occurs.
  • the invention is based upon the consideration that the mass striking the fixed contact on the one hand and the velocity of this mass on the other are responsible for rebound.
  • the impinging mass is reduced by lifting the actuating element from the moving contact at the moment of closing so that only the small mass of the moving contact is effective.
  • the velocity is so adjusted by relating the strength of the closing spring to the strength of the omega spring, that the rebound effect becomes small or is even entirely suppressed. This matching of the springs is possible because the difference can be adjusted with the help of the stops, so that the omega spring is available for these matching purposes.
  • the procedure is preferably such that the omega spring is rated beforehand relatively to the closing spring-in such manner that a short rebound period results.
  • very large tolerances such as are unavoidable in the case of omega springs can be accepted, since adjustment in the sense of obtaining minimum rebound is possible.
  • the contact system can also include two movable contacts one of which is lifted from the associated fixed contact in each of the two positions of the snap-action system. If this contact system is arranged in a completely symmetrical manner, a satisfactory adjustment to suit the two closing springs can be achieved by appropriately setting the omega spring. If however there is a danger of the closing springs also exhibiting some differences as regards tolerances, it is advantageous to be able to effect an adjustment in this case too.
  • both stops can be adjustable symmetrically with respect to each other, so that the mean temperature is maintained upon altering the difference.
  • the symmetrical construction is of considerable advantage particularly when use is made of acontact system employing two movable contacts. 1
  • the actuating element can occupy an at-rest position such that in travelling to the movable contact it covers a greater lost-motion distance than is necessary for separating the masses.
  • the actuating element will have developed considerable velocity before striking the moving contact, so that the switch opens very rapidly.
  • the main arm can itself be constituted by an operating element.
  • the main arm is constituted by a bimetal strip. This results in a room thermostat of extremely simple construction.
  • a contact-closing spring in the form of a leaf spring can be loaded by an adjustable screw. In this way the strength of the omega spring can be suited in a simple manner.
  • FIG. 1 is a side view of the switch of the invention, constituting a room thermostat incorporating a bimetal actuation means,
  • FIG. 2 is a plan view with a section through the spindle of V the adjusting device
  • FIG. 3 is an exploded view of those system important to its operation.
  • the room thermostat is accommodated in a casing 1, having a cover 2 shown in broken lines.
  • a knob 3 for setting the working points passes through the cover.
  • a connection system 4, a snap-action system 5 and a contact system 6 are accommodated side by side in the casing.
  • connection system 4 comprises an inlet 7 in the base and a row of connecting screws 8 on each side of the inlet.
  • the snap-action system 5 is mounted on a base plate 9 which is secured to the base of the casing by means of screws 10. At opposite end-faces, the base plate carries bent-up tabs 11 containing tapped holes 12 for securing the cover 2. Tabs 13, 14 and 15 are bent up at one side. The tab 13 carries a leaf spring 16 which constitutes both blades 17 and a guide tab 18 for a first fixed support. The tab 14 carries blades 19 forming a second fixed support. The tab 15 is tapped to accommodate a set-screw 20 forming a stop.
  • the base-plate also contains a fixing hole 21 for receiving a spindle 22 of the adjusting device which takes the form of a cam disc 23 and is firmly connected to the setting knob 3.
  • a bimetal main arm 24 is provided at one end with a first attachment 25, in the form of a U-shaped stirrup and, at the other end, with a second attachment constituted by a block 26 of insulating material. Whilst the main arm 24 is secured to the limb 27 of the stirrup 25, the opposite limb 28 of the stirrup carries a second bimetal strip 29 which bends in the opposite direction to the main arm 24.
  • the second bimetal strip 29 acts as an adjusting lever and, under the action of the leaf spring 16, bears against the cam disc 23 of the adjusting means, by way of a set-screw 30.
  • the main arm 24 and the bimetal strip 29 contain slots 31 and 32 through which air can pass. The slot 31 also enables the screw 30 to be actuated.
  • the central web 33 of the stirrup 25 contains an elongate recess 34, in which are accommodated the blades 17. At its middle, the recess contains an orifice which receives the guide tab 18.
  • the block 26 contains a first pair of lateral grooves 35 into which extend the limbs 36 of a U-shaped sheet-metal stamping 37.
  • the end edge of this constitutes a knife-edge support 38 for flexible connection to one end 39 of an omega spring 40, the other end 41 of which is held in the blade 19 of the second fixed support.
  • a screw 42, driven into the block 26, acts on the inner edge 43 of the sheet-metal stamping 37, which is pressed by the omega spring 40 against the end of the screw.
  • a second pair of lateral grooves 44 in the block 26 is used for securing it to the main arm 24.
  • this main arm contains an orifice 45 having a stepped edge.
  • the first portion 46 is of suchcross-section that the block 26 can be pushed through it.
  • the second stepped portion 47 however forms guides along which the block 26 can be pushed by its lateral grooves 44 under the effect of the omega spring 40. Also, on an extension 48, the block 26 carries an actuating element 49 for displacing the contact system.
  • the set-screw stop 20 can,
  • the contact system incorporates a fixed middle double contact 54 and two outer movable contacts 55 and 56.
  • Each contact is mounted on a carrier 57, 58 and 59, the central one 58 of which is substantially rigid, whereas the two outer carriers 57 and 59 take the form of leaf springs and are rendered rigid at their outer parts by tabs 60 bent up at the side.
  • These leaf springs are held at their other ends in fixed clamping means 61 and 62, which are fitted with set-screws 63 and 64 with the help of which the bias of these leaf springs can be adjusted.
  • These leaf springs are closing springs which resiliently press the movable contacts 55 and 56 intheir at-rest positions against the fixed contact 54.
  • the outer carriers 57 and 59 extend so far beyond the associated contacts that the actuating element 49 can engage them and can lift the contacts from the fixed contact, thereby overcoming the spring force of their support.
  • the moving spring is altered by this adjustment. Additional phasing can be achieved with the help of the set-screws 63 and 64, by means of which the bias of the closing springs 57 and 59 can be altered. By these measures it is possible to keep rebound extraordinarily small or even to suppress it entire]
  • the difference in the room thermostat can be set with the help of the set-screw stops 20 and 52.
  • the two end points of the snap-action movement are positioned symmetrically on both sides of the dead-centre line of the snap-action system.
  • the required room temperature is set with the help of the setting knob 3, which when rotated causes the main arm 24 to swing, through the agency of the cam disc 23.
  • the scale on the setting knob 3 can be accurately calibrated with the help of the screw 30.
  • bimetal main arm 24 instead of the bimetal main arm 24, use can also be made of a rigid main arm which, for example, is acted on by a thermostatic or pressure-influenced working element and a spring having a nominal rating.
  • a thermostatic switch assembly comprising, a frame, a bimetal strip secured to said frame and forming a main arm, a fixed contact, a movable contact, a leaf type contact spring attached to said frame and said movable contact for biasing said movable contact in the direction of said fixed contact, lug means attached'adjacent said movable contact, an actuating element on said main arm for engaging said lug means to move said movable contact away from said fixed contact, said actuating element having a displacement range so as to be separated from said lug means when said fixed and movable contacts are in abutting engagement, an omega spring supported on said frame and operatively connected to adjustable means on said actuating element, said adjustable means movable relative to said actuating element to vary the characteristics of said omega spring and hence the velocity of said actuating element, said adjustable means and set screw means for making the bias of said contact spring adjustable cooperating to control the rebound characteristics of said contact spring.

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  • Thermally Actuated Switches (AREA)
  • Toys (AREA)
US3065A 1969-02-14 1970-01-15 Electric switch with a snap-action system Expired - Lifetime US3656081A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19691907419 DE1907419B2 (de) 1969-02-14 1969-02-14 Elektrischer schalter mit schnappsystem

Publications (1)

Publication Number Publication Date
US3656081A true US3656081A (en) 1972-04-11

Family

ID=5725251

Family Applications (1)

Application Number Title Priority Date Filing Date
US3065A Expired - Lifetime US3656081A (en) 1969-02-14 1970-01-15 Electric switch with a snap-action system

Country Status (12)

Country Link
US (1) US3656081A (fr)
JP (1) JPS5012581B1 (fr)
BE (1) BE742794A (fr)
CH (1) CH503366A (fr)
DE (1) DE1907419B2 (fr)
DK (1) DK137357B (fr)
ES (1) ES374499A1 (fr)
FR (1) FR2031082A5 (fr)
GB (1) GB1297102A (fr)
NL (1) NL7001941A (fr)
NO (1) NO130610C (fr)
SE (1) SE360504B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194102A (en) * 1977-12-29 1980-03-18 Robertshaw Controls Company Condition responsive electrical switch construction and parts and methods therefor
US4363015A (en) * 1977-12-29 1982-12-07 Robertshaw Controls Company Condition responsive electrical switch construction and parts and methods therefor

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51127689U (fr) * 1975-04-10 1976-10-15
JPS5698638U (fr) * 1979-12-26 1981-08-04

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1977393A (en) * 1934-10-16 Temperature control device
US2472709A (en) * 1947-02-06 1949-06-07 Bell Telephone Labor Inc Control of electrical contacting elements
FR1042226A (fr) * 1951-09-15 1953-10-29 Wilcolator Co Thermostat à déclenchement brusque
US2713100A (en) * 1951-03-05 1955-07-12 William Wesley Hicks Thermostatic switch
CA527612A (fr) * 1956-07-10 E. Armstrong Charles Thermostat
DE1002542B (de) * 1955-04-23 1957-02-14 Licentia Gmbh Elektrisch gesteuerter Temperaturregler, insbesondere fuer Kuehlschraenke
US2833893A (en) * 1956-11-16 1958-05-06 Robertshaw Fulton Controls Co Thermostatic switch
US3256402A (en) * 1964-01-02 1966-06-14 Gen Electric Switch relay for use in electric motors
US3290629A (en) * 1964-05-25 1966-12-06 Bell Telephone Labor Inc Wire spring relay with improved means for determining contact force
US3462722A (en) * 1966-11-16 1969-08-19 Therm O Disc Inc Thermostatic control with adjusting cam

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1977393A (en) * 1934-10-16 Temperature control device
CA527612A (fr) * 1956-07-10 E. Armstrong Charles Thermostat
US2472709A (en) * 1947-02-06 1949-06-07 Bell Telephone Labor Inc Control of electrical contacting elements
US2713100A (en) * 1951-03-05 1955-07-12 William Wesley Hicks Thermostatic switch
FR1042226A (fr) * 1951-09-15 1953-10-29 Wilcolator Co Thermostat à déclenchement brusque
DE1002542B (de) * 1955-04-23 1957-02-14 Licentia Gmbh Elektrisch gesteuerter Temperaturregler, insbesondere fuer Kuehlschraenke
US2833893A (en) * 1956-11-16 1958-05-06 Robertshaw Fulton Controls Co Thermostatic switch
US3256402A (en) * 1964-01-02 1966-06-14 Gen Electric Switch relay for use in electric motors
US3290629A (en) * 1964-05-25 1966-12-06 Bell Telephone Labor Inc Wire spring relay with improved means for determining contact force
US3462722A (en) * 1966-11-16 1969-08-19 Therm O Disc Inc Thermostatic control with adjusting cam

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194102A (en) * 1977-12-29 1980-03-18 Robertshaw Controls Company Condition responsive electrical switch construction and parts and methods therefor
US4363015A (en) * 1977-12-29 1982-12-07 Robertshaw Controls Company Condition responsive electrical switch construction and parts and methods therefor

Also Published As

Publication number Publication date
GB1297102A (fr) 1972-11-22
DE1907419B2 (de) 1971-12-09
SE360504B (fr) 1973-09-24
DK137357B (da) 1978-02-20
CH503366A (de) 1971-02-15
DE1907419A1 (de) 1970-11-05
NO130610B (fr) 1974-09-30
FR2031082A5 (fr) 1970-11-13
BE742794A (fr) 1970-05-14
NL7001941A (fr) 1970-08-18
ES374499A1 (es) 1972-01-01
JPS5012581B1 (fr) 1975-05-13
NO130610C (fr) 1975-01-08
DK137357C (fr) 1978-07-24

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