US3735069A - Snap-action electric switch - Google Patents

Snap-action electric switch Download PDF

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Publication number
US3735069A
US3735069A US00215488A US3735069DA US3735069A US 3735069 A US3735069 A US 3735069A US 00215488 A US00215488 A US 00215488A US 3735069D A US3735069D A US 3735069DA US 3735069 A US3735069 A US 3735069A
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US
United States
Prior art keywords
lever
spring
snap
force
stop means
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
US00215488A
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English (en)
Inventor
J Andresen
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.)
Danfoss AS
Original Assignee
Danfoss AS
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 claimed from DE19712101195 external-priority patent/DE2101195C/de
Application filed by Danfoss AS filed Critical Danfoss AS
Application granted granted Critical
Publication of US3735069A publication Critical patent/US3735069A/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
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/60—Means for producing snap action
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/002—Thermally-actuated switches combined with protective means

Definitions

  • the actuating lever is not only acted upon by moderate forces in the usual way to provide the usual control but, in addition, is also acted upon by larger forces in response to extreme conditions in a system. These larger forces move the displaceable stops and one or more auxiliary switch means are provided which are actuated under these circumstances to provide control under the extreme conditions referred to.
  • the invention relates to a snap-action electric switch having a force-proportional snap-action system which comprises an actuating lever, movable between two stops, and a snap-action spring, the actuating lever being operated by a displacement force.
  • force-proportional control is in contrast with distance-proportional control that is almost always used.
  • the former method of control is based upon the fact that the snap-action spring produces a force component in the direction of the displacement force, and has a negative spring characteristic.
  • the actuating lever is urged against the stop by the sum of the displacement force and the force component of the snap-action spring. The system remains in this position until the displacement force falls below the force component of the snap-action spring. Snap-over into the other end position determined by the second stop then takes place.
  • the actuating lever and the snap-action spring are required for a force-proportional snap-action system. This results in a very simple construction and in ease of assembly. Also, the masses that have to be moved are relatively small. Furthermore, if the set of contacts to be actuated are separated from the actuating lever, extremely short periods of bounce results.
  • a typical example is constituted by condenser thermostats in cold-boxes or refrigerating cabinets, in which an operating element, dependent upon the condenser temperature, acts on a snap-action electric switch, thereby overcoming the force of a rated-value spring. If the temperature inside the cold-box or refrigerating cabinet exceeds an upper limiting value, then this is a fault which should be indicated. If the operating element is not properly sealed, then the cold-box or refrigerating cabinet will operate continuously. This is also a fault which should be indicated. Considerable difficulties have hitherto been encountered in providing additional indications of this kind.
  • the object of the invention is to provide an electric snap-action system whereby not only is the normal control carried out in a simple manner, but it is also'possible to indicate in a simple way when a limiting value has been exceeded.
  • this object is achieved by at least one of the stops being adapted to be movable from its at-rest position by the actuating lever against the force of an additional spring when the displacement force exceeds or falls below a predetermined limiting value, and by a signal being released by the movement of the stop.
  • the stop may be linked for example to a contact for starting off a signal.
  • the signal is then passed on by electrical means. When this happens however, normal operation of the snap-action switch is not interfered with.
  • an element carrying the stop is pressed in its at-rest position against a backing element by the additional spring.
  • the position of the stop is thus precisely defined. It will pass beyond this position only if the force of the additional spring is exceeded by the forces occurring in the snap-action system.
  • one element may carry both stops and may be held between two additional springs acting in opposite directions, a fixed limit being associated with at least one of the additional springs. If the two addi tional springs are of different strength, the limit should be associated with the stronger of the springs.
  • the additional spring takes the form of a leaf spring and extends substantially parallel with the actuating lever.
  • the contact for starting off the signal may be actuable by the free end of the leaf spring.
  • the snap-action switch has a snap-action system which consists of an actuating lever 1 and a snap-action spring 2 which is bent to the shape of the Greek letter omega. These parts are mounted in two fixed bearings 3 and 4 and are linked with each other by way of a movable bearing 5. Fitted to the actuating lever 1 is a dog 6 which actuates a reversing switch 7.
  • the reversing switch consists of a fixed double contact 8 and two movable contacts 9 and 10 which are mounted on contact springs 11 and 12. The dog 6 engages the free ends of the contact springs 11 and 12.
  • the actuating lever l is able to move between two stops l3 and 14. It is loaded on the one hand by an operating element 15, which is connected through a capillary tube to a sensor which measures the condenser temperature, and on the other by a rated-value spring 16 which can be adjusted with the aid of a rotatable know 17. In the position illustrated, the force of the rated-value spring 16 is fixed. Also, the snap-action spring 4 2 has a certain upwardly directed force component.
  • the two stops 13 and 14 are provided on a displaceable element 18 which is loaded at the top by a leaf spring 19 and at the bottom by another leaf spring 20.
  • the at-rest position of the element 18 is determined by two limiting means 21 and 22 for the leaf springs 19 and 20.
  • Associated with the leaf spring 19 is a fixed contact 23 and a movable contact 24 which is mounted on a contact spring 25.
  • Associated with the leaf spring 20 is a fixed contact 26 and a movable contact 27 which is mounted on a contact spring 28.
  • the free ends of the contact springs 25 and 28 are engaged by the leaf springs 19 and 20, so that the pairs of contacts 23 and 24, and 26 and 27 are open in the illustrated at-rest position.
  • Also provided are fixed limits 29 and 30 which prevent excessive displacement of the element 28.
  • the actuating lever 1 displaces the stop 13 and thus the element 18 in the upward direction, thereby overcoming the force of the spring 19, and closes the pair of contacts 23 and 24 so as to send an appropriate signal. If the operating element 15 is not properly sealed so that the rated-value spring 16 alone is effective, the actuating lever 1 not only moves into the position set by the stop 14, but also moves the element 18 to overcome the force of the spring 20, so that the pair of contacts 26 and 27 close and an appropriate signal is sent. In both cases the contact springs 1 l and 12 are able to yield, so that the additional function is not adversely affected.
  • the actuating lever 1 cannot continuously return to the at-rest position it previously occupied when the displacement force returns to the normal range. Rather, the displacement force must fall below or exceed a force resulting from the corresponding force component of the snap-action spring 2. Then the stop element 18 springs back into the normal position and the lever 1 bears against the opposite stop.
  • This snap-action switch may of course be used for other purposes, e.g. for a room thermostat in which the actuating lever 1 is constituted by a bimetal strip, in a pressostat or in any other control equipment in which the actuating lever l is acted upon by a displacement force.
  • a snap action electric switch assembly comprising a pair of fixed supports with an actuating lever and a snap action spring disposed therebetween, an operating element biasing said lever in one direction and spring means biasing said lever in the opposite direction, a linearly displaceable control member movable in a transverse direction relative to the biasing direction of said operating element, said control member having an opening defined by wall means, said lever extending through said opening, said opening wall means forming stop means which define the limits of a first range of movement of said lever when said control member is in a neutral position, first switch means actuated by said lever within said first range limits defined by said stop means, spring means opposing movement of said control member in at least one direction, said stop means presenting a predetermined resistance force to movement in at least one direction and being movable in said one direction when a force exceeding said predetermined resistance force is exceeded in the engagement of said lever with said stop means, and second switch means actuated when said stop means is moved a predetermined distance.
  • a snap action electric switch assembly according to claim 1 wherein there are a pair of said stop means on said displaceable member and there are a pair of said spring means respectively opposing movement of said displaceable member in each direction.

Landscapes

  • Thermally Actuated Switches (AREA)
  • Push-Button Switches (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)
US00215488A 1971-01-12 1972-01-05 Snap-action electric switch Expired - Lifetime US3735069A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712101195 DE2101195C (de) 1971-01-12 Elektrischer Schnappschalter

Publications (1)

Publication Number Publication Date
US3735069A true US3735069A (en) 1973-05-22

Family

ID=5795651

Family Applications (1)

Application Number Title Priority Date Filing Date
US00215488A Expired - Lifetime US3735069A (en) 1971-01-12 1972-01-05 Snap-action electric switch

Country Status (6)

Country Link
US (1) US3735069A (enExample)
CH (1) CH536547A (enExample)
DK (1) DK126884B (enExample)
FR (1) FR2121794B1 (enExample)
GB (1) GB1369512A (enExample)
IT (1) IT943280B (enExample)

Cited By (7)

* 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
US4652706A (en) * 1986-01-29 1987-03-24 Tower Manufacturing Corporation Double pole switch construction
US4937549A (en) * 1989-10-02 1990-06-26 General Electric Company Condition responsive switching apparatus
US5101188A (en) * 1989-10-02 1992-03-31 General Electric Company Condition responsive switching apparatus
US5467523A (en) * 1994-09-01 1995-11-21 General Electric Company Method for assembling and calibrating a condition-responsive electric switch mechanism
US5585774A (en) * 1994-09-01 1996-12-17 General Electric Company Condition-responsive electric switch mechanism

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE8103768U1 (de) * 1981-02-12 1981-09-24 Eaton S.A.M., Monaco "Druckbetätigte elektrische Schaltvorrichtung"
IT1258227B (it) * 1991-11-15 1996-02-21 Ma Ter Srl Pressostato con microinterruttore di sicurezza a riarmo manuale
IT1252296B (it) * 1991-11-15 1995-06-08 Ma Ter Srl Pressostato a sfioro, con microinterruttore di sicurezza a riarmo manuale

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3617665A (en) * 1968-12-13 1971-11-02 Controls Co Of America Snap-action pressure-sensitive switch with safety feature responsive to contact welding

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3617665A (en) * 1968-12-13 1971-11-02 Controls Co Of America Snap-action pressure-sensitive switch with safety feature responsive to contact welding

Cited By (7)

* 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
US4652706A (en) * 1986-01-29 1987-03-24 Tower Manufacturing Corporation Double pole switch construction
US4937549A (en) * 1989-10-02 1990-06-26 General Electric Company Condition responsive switching apparatus
US5101188A (en) * 1989-10-02 1992-03-31 General Electric Company Condition responsive switching apparatus
US5467523A (en) * 1994-09-01 1995-11-21 General Electric Company Method for assembling and calibrating a condition-responsive electric switch mechanism
US5585774A (en) * 1994-09-01 1996-12-17 General Electric Company Condition-responsive electric switch mechanism

Also Published As

Publication number Publication date
FR2121794A1 (enExample) 1972-08-25
IT943280B (it) 1973-04-02
DE2101195A1 (de) 1972-07-27
DE2101195B2 (de) 1972-11-30
DK126884B (da) 1973-08-27
CH536547A (de) 1973-04-30
GB1369512A (en) 1974-10-09
FR2121794B1 (enExample) 1977-04-01

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