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US3534314A - Thermal relay with two heated bimetallic strips - Google Patents

Thermal relay with two heated bimetallic strips Download PDF

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Publication number
US3534314A
US3534314A US595688A US3534314DA US3534314A US 3534314 A US3534314 A US 3534314A US 595688 A US595688 A US 595688A US 3534314D A US3534314D A US 3534314DA US 3534314 A US3534314 A US 3534314A
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US
United States
Prior art keywords
bimetal
contact
bimetal strip
strips
relay
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
US595688A
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English (en)
Inventor
Jakob Philipp Ellenberger
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.)
Ellenberger and Poensgen GmbH
Original Assignee
Ellenberger and Poensgen GmbH
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 Ellenberger and Poensgen GmbH filed Critical Ellenberger and Poensgen GmbH
Application granted granted Critical
Publication of US3534314A publication Critical patent/US3534314A/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
    • H01H43/00—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed
    • H01H43/30—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to thermal action
    • H01H43/301—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to thermal action based on the expansion or contraction of a material
    • H01H43/302—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to thermal action based on the expansion or contraction of a material of solid bodies
    • H01H43/304—Time or time-programme switches providing a choice of time-intervals for executing one or more switching actions and automatically terminating their operations after the programme is completed with timing of actuation of contacts due to thermal action based on the expansion or contraction of a material of solid bodies of two bodies expanding or contracting in a different manner, e.g. bimetallic elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H61/00—Electrothermal relays
    • H01H61/02—Electrothermal relays wherein the thermally-sensitive member is heated indirectly, e.g. resistively, inductively

Definitions

  • the present invention relates to a time-delay relay which is provided with a pair of heated opposite substantially parallel bimetal strips which are spaced from each other for the actuation of switch contacts. More particularly, the invention relates to improvements in a time-delay relay of the above-mentioned type and of a known design in which the two bimetal strips are secured to a block of insulating material and are surrounded by heating coils. The free end of one of the bimetal strips is provided with a double contact which, when the relay is in its resting position, is located loosely between the two arms of a U-shaped contact which is secured to but insulated from the end of the other bimetal strip.
  • the heating coils of the two bimetal strips may be connected in series with the filaments of light bulbs which are used for illuminating a motor vehicle. If one of the filaments is broken, the circuit of the heating coil of one bimetal strip is interrupted so that the latter cools otf with the result that the contacts of both bimetal strips are connected to each other.
  • the invention provides that the bimetal strip the free end of which actuates the switch contacts is rigidly connected at its other end to the free end of the second bimetal strip the other end of which is secured in a fixed position.
  • the outside temperature has no more a detrimental influence upon therelay according to the invention than upon the known time-delay relay as previously described.
  • An important feature of the relay according to the invention consists in the possibility of employing. both bimetal strips as operating bimetal strips and of controlling them in such a manner that one bimetal strip is used for switching the relay to the on-position and the other bimetal strip for switching it to the elf-position.
  • both bimetal strips may be of the same construction for fully compensating the temperature, they may also be of different constructions so as to attain selectively either an overcompensation or undercompensation of the temperature.
  • the bimetal strips may be heated either directly or indirectly for which both strips may be provided with separate heating coils. The dimensions of these heating coils are dependent upon the electric control impulses.
  • Another feature of the invention consists in providing the bimetal strip which actuates the switch contacts near its rigidly secured end with a contact which is connected to one end of its heating coil and upon which a contact of a contact spring engages when the other, rigidly mounted bimetal strip is in a cold condition.
  • the contact of the contact spring may be adjust in a manner known as such to its accurate position by means of a setscrew upon which the contact spring engages under an initial tension.
  • the relay When the heating coil of the bimetal strip which actuates the switch contacts is energized by a current impulse of a sufiicient strength, the relay according to the invention will carry out a switching movement in one direction and when the heating coil of the second bimetal strip is energized, the relay will carry out a switching movement in the other direction.
  • the contact which is provided on the actuating bimetal strip and the contact of the contact spring have the effect that the coil of this bimetal strip cannot become effective until the other bimetal strip has cooled 01f. If this other bimetal strip is heated by its heating coil, the switch contacts will be separated which prevents the other bimetal strip also from being energized.
  • Another feature of the invention consists in connecting the free end of the bimetal strip which actuates the switch contacts to the control lever of a micro-switch by making this end of a bifurcated shape the two arms of which embrace the control lever and thus form a simple and reliable connection of the bimetal strip with the control lever of the microswitch.
  • This microswitch may be provided in a conventional manner in the form of a snap switch so as to prevent the control lever of the microswitch from being automatically reversed by the bi-metal strip when the latter is cooling off. This permits the microswitch to remain in a certin desired position for any length of time.
  • the housing of the microswitch which is slidable within the housing of the relay by being provided with lateral projections which are guided in grooves in the relay housing which extend vertically to the bimetal strip is pressed by at least one spring in the direction of the grooves against a setscrew.
  • the microswitch will be adjusted either by or against the action of the spring so that its control lever will in the cold condition be properly connected to the associated bimetal strip.
  • each heating coil of both bimetal strips may be connected to each other, while the other end of one heating coil may be connected to one contact of the microswitch and the contact spring to another contact thereof.
  • the bimetal strips which are heated by their heating coils will then automatically switch oif their respective heating coils. This automatic switching on and off of the heating coils will continue until the entire circuit is interrupted.
  • the time-delay relay according to the invention may be employed, for example, for switching control mechanisms at greater time intervals from one particular condition to another.
  • the switching operation is then produced by time-limited current impulses, the length of which may be equal or different for the two switching operations.
  • the time-delay relay according to the invention may also be employed as an interval relay which may effect certain switching operations at predetermined time inter- 3 vals.
  • the contact of the contact spring and the corresponding contact of the bimetal strip may then serve for stabilizing the thermal capacities on the bimetal strip and will thereby attain uniform time intervals.
  • the contact of the contact spring and the associated contact on the corresponding bimetal strip cause a locking of the latter if the operating impulse lasts for a greater length of time or if there is a variation in the current which may be caused, for example, by voltage differences.
  • the two bimetal strips may be pivotably mounted at their ends which are connected to each other. If the bimetal strip is bent which actuates the switch contacts, it will be substantially braced on the fixed pivot point. If the other bimetal strip is bent, the bimetal strip which actuates the microswitch will be pivoted about the pivot point. The actuation of the microswitch will thus be facilitated and the switch contacts will be switched over very accurately.
  • the two bimetal strips may be connected to each other, for example, by means of a block of insulating material which is pivotably mounted on a stationary bolt.
  • the second bimetal strip opposite to the actuating bimetal strip is secured to a setscrew on the end opposite to the insultating block. By actuating this setscrew, it is possible to vary the position of the free end of the actuating bimetal strip relative to the switch contacts and thus to adjust this position very accurately.
  • Another feature of the invention consists in the provision of a contact spring the contact of which cooperates With an adjustable fixed contact and which is secured to and extends parallel to the actuating bimetal strip the heating coil of which is connected in series with a pair of contacts. Since this contact spring does not project laterally over the two bimetal strips, it is possible to make the switch very narrow in the direction transverse to the bimetal strips.
  • the wiring of the relay may be considerably simplified by employing bare connecting wires within the relay and by inserting them into bores or grooves in the housing which consists of insulating material. These grooves are preferably provided in the lower side of the housing.
  • the electric connections between the elements of the relay to the connecting terminals thereof may, of course, also be provided by a printed circuit.
  • FIG. 1 shows a side view of the time-delay relay according to the invention
  • FIG. 2 shows an end view of the relay as seen from the left of FIG. 1;
  • FIG. 3 shows a cross section which is taken along the line IIIIII of FIG 2;
  • FIG. 4 shows a top view of FIG. 1
  • FIG. 5 shows a cross section of the microswitch according to FIG. 3;
  • FIG. 6 shows a circuit digram of the two heating coils of the bimetal strips and the microswitch
  • FIG. 7 shows a top view of another embodiment of the time-delay relay according to the invention in the open condition
  • FIG. 8 shows a cross section which is taken along the line VIII-VIII of FIG. 7;
  • FIG. 9 shows a bottom view of the relay according to FIG. 8.
  • FIG. 10 shows a diagrammatic view of the two bimetal strips according to FIG. 7 before and after they are bent.
  • FIG. 11 shows a circuit diagram of the time-delay relay as illustrated in FIGS. 7 to 9.
  • the time-delay relay as illustrated in FIGS. 1 to 4 of the drawings comprises a base plate 1 of insulating material which is provided with a projection 2 which is integrally molded thereon.
  • Base plate 1 carries a bimetal strip 4 which is secured thereto at the point 3 and is provided with a heating coil 5, the ends of which are connected to the terminals 6 and 7.
  • a block of insulating material 8 is rigidly secured to the left end of the bimetal strip 4.
  • This insulating block 8 may consist of two equal parts which are secured to each other by a screw 9.
  • both parts of the insulating block 8 are provided with cuts 11 and 12 into which the two bimetal strips 4 and 10 are inserted.
  • the bimetal strip 10 carries a heating coil 13 one end of which is connected to a terminal 14. Adjacent to its end which is secured to the insulating block 8, the bimetal strip 10 is provided with a contact part 15 with a contact 16 thereon which is operatively associated with a contact 17 on one end of a contact spring 18 the other end of which is rigidly secured to a projection 19 on base plate 1.
  • a setscrew 20 is screwed into the base plate 1 and contact spring 18 engages thereon under tension.
  • Contact spring 18 is electrically connected to a terminal 21.
  • the two bimetal strips 4 and 10 and their heating coils 5 and 13 may be of equal dimensions so as to attain a full temperature compensation of the relay.
  • the right end of the bimetal strip 10 as shown in FIG. 1 is made of a bifurcated shape so as to form two arms 22 and 23 between which one end of a control level 24 of a microswitch 25 engages.
  • This control lever 24 is pivotally mounted at 26 on the housing 27 of the microswitch 25.
  • this microswitch is provided with six contact springs 28 to 33.
  • the movable contact springs 29 and 32 are connected at their right ends to an insulating plate 34 which has a central projection 35 which is connected to a similar projection 35 on the control lever 24 by means of a substantially C-shaped tensioned spring 36 which acts as a snap member so that the switching movements of the toggle switch will occur abruptly.
  • Base plate 1 is further provided underneath the bimetal strip 4 and the insulating block 8 with an aperture 37.
  • the housing 27 of the microswitch 25 is composed of several parts which are secured to each other by pins 38 which project laterally from the housing 27 and the ends of which engage into and are slidable along vertical grooves 39 in the two side walls of a recess 40 in the projection 2 of base plate 1 so as to permit the housing 27 of the microswitch to move in the vertical direction.
  • a spring 41 presses this housing 27 against a setscrew 42 which is screwed into a plate 43 which is secured to the projection 2.
  • This setscrew 42 permits the microswitch 25 to be adjusted within the recess 40 to such a position that, when the relay is in its inactive position, the narrow end 24' of the control lever 24 will engage between the two arms 22 and 23 on the end of the bimetal strip 10.
  • the mode of operation of the time-delay relay as illustrated in FIGS. 1 to 4 is as follows:
  • a current impulse is passed through the heating coil 13 on the bimetal strip 10 so that the latter bends downwardly and thereby pivots the control lever 24 in the clockwise direction to the other switching position in which the contacts of the movable contact springs 29 and 32 engage upon the contacts of the fixed contact springs 28 and 31.
  • the heating coils 5 and 13 are connected at one end at 44 to each other and then to one terminal 45 of a source of current.
  • the other end of heating coil 13 is connected through the contact spring 18 to the contact 33 of the microswitch 25, while the heating coil 5 is connected to the contact 31 of the microswitch 25; If the mentioned circuit is closed, the microswitch 25 will be switched over by the heated bimetal strip 25 so that the contact on contact spring 29 will then engage upon the contact 30 and the contact on contact 32 upon the contact 33.
  • the circuit of heating coil 13 will, however, not be closed by the contacts 16 and 17 until the bimetal strip 4 has cooled off.
  • the time-delay relay as illustrated in FIGS. 7 to 9 comprises a housing 46 of insulating material which has a projection 47 integrally molded thereon and may be covered up by a cover, not shown, which may likewise consist of insulating material and is preferably transparent.
  • a cover not shown, which may likewise consist of insulating material and is preferably transparent.
  • the housing 46 and the projection 47 are each provided with an eye 48 for receiving a bolt.
  • the terminals 49 to 53 are provided on housing 46.
  • a pin 54 is secured on which an insulating block 55 is pivotably mounted.
  • This insulating block 55 may consist of two parts which are provided with cuts 56 and 57 into which the bimetal strips 58 and 59 are inserted. They may be secured to the insulating block 55 by connecting the two halves of the latter to each other by means of screws or by a hollow rivet through which the pin 54 is inserted.
  • the two bimetal strips 58 and 59 carry heating coils 60 and 61 which are electrically insulated therefrom.
  • the left end of the bimetal strip 58 as shown in FIG. 7 is secured to a setscrew 62 on housing 46, preferably by being hooked into an annular groove 63 in setscrew 62.
  • the other bimetal strip 59 is provided with a contact spring 64 which may, for example, be soldered, welded or screwed thereon. On its free end, contact spring 64 carries a contact 65 which in the position as shown in FIG. 7 engages upon an opposite adjustable contact 66.
  • the left end 67 of bimetal strip 59 is bifurcated, and between the two arms of this bifurcated end 67 the free end of the control lever 24 of the microswitch 25 is loosely inserted.
  • This microswitch 25 is provided with six terminal strips 28 to 33.
  • the connecting wires 68 between these terminal strips 28 to 33 or the heating coils 60 and 61 of the two bimetal strips 58 and 59 and the terminal strips 49 to 53 are passed through bores 69 in the bottom of housing 46 and then within grooves 70 in the lower side of this bottom so as to be completely insulated from each other. These connecting wires 68 may therefore be completely bare of any insulation.
  • the mode of operation of the time-delay relay according to FIGS. 7 to 9 is as follows:
  • bimetal strips 58' and 59 are bent in the upward direction, one bimetal strip serves for the temperature compensation of the other strip so that the outer temperature will have no influence upon the relay.
  • contact 65 on contact spring 64 disengages from the opposite fixed contact 66 so that the circuit of heating coil 61 on the bimetal strip 59 will be interrupted. As long as this interruption continues, heating coil 61 cannot be supplied with current and the bimetal strip 59 therefore cannot be bent.
  • the time-delay relay may be controlled by current impulses of a length greater than that which is required for switching over the bimetal strips.
  • the pair of contacts 65 and 66 prevents the bimetal strip 59 from also being bent by the same current impulse which causes the bimetal strip 58 to bend. Consequently, it is definitely insured that the microswitch 25 cannot be switched back except by a second impulse after the first impulse has been completed.
  • the circuit diagram as shown in FIG. 11 illustrates that each current impulse which is received by the terminals 52 and 53 will change the microswitch to such a position that the circuit of the heating coil of one bimetal strip will be interrupted and the circuit of the heating coil of the other bimetal strip will be closed. However, the circuit of heating coil 61 of the bimetal strip 59 will not be closed until the two contacts 65 and 66 are also closed.
  • a thermal relay comprising, a support means, first and second bimetallic strips rigidly connected with each other on said support means at their respective first ends in spaced apart parallel relationship, said first strip secured at the second end to said support means, movably mounted switch means operatively loosely connected to the second end of said second strip,
  • additional switch means including a first contact on said second bimetallic strip at a point adjacent said first secured end thereof and connected to one end of the heating coil on said second strip, and
  • a contact spring mounted on said support means having a second contact thereon for engaging said first contact when said first bimetallic strip is in one position
  • said firstmentioned switch means comprise a microswitch having a control lever pivotable at one end for actuating said switch contacts, said second end of said second strip being connected to the other end of said control lever for pivoting the same.
  • a relay as defined in claim 1 further comprising means for pivotably mounting said interconnected ends of said two strips, in which said means comprise a stationary pin, and a block of insulating material to which said first ends of said two strips are secured and which is pivotably mounted on said pin.
  • a relay as defined in claim'7 further comprising a setscrew, attached to said support means, said first strip being secured at its second end to said setscrew.

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  • Thermally Actuated Switches (AREA)
  • Control Of Resistance Heating (AREA)
US595688A 1965-12-23 1966-11-21 Thermal relay with two heated bimetallic strips Expired - Lifetime US3534314A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEE30724A DE1283392B (de) 1965-12-23 1965-12-23 Thermisches Verzoegerungsrelais
DEE31178A DE1301859B (de) 1965-12-23 1966-03-08 Thermisches Verzoegerungsrelais

Publications (1)

Publication Number Publication Date
US3534314A true US3534314A (en) 1970-10-13

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ID=25973377

Family Applications (1)

Application Number Title Priority Date Filing Date
US595688A Expired - Lifetime US3534314A (en) 1965-12-23 1966-11-21 Thermal relay with two heated bimetallic strips

Country Status (5)

Country Link
US (1) US3534314A (de)
CH (1) CH450551A (de)
DE (2) DE1283392B (de)
DK (1) DK126458B (de)
GB (1) GB1165167A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4307367A (en) * 1980-04-15 1981-12-22 Magic Chef, Inc. Bi-stable relay
US4481494A (en) * 1983-01-31 1984-11-06 Therm-O-Disc, Incorporated Bi-metal snap disc operated relay
US20140166639A1 (en) * 2011-08-03 2014-06-19 Schneider Electric Industries Sas Bimetal thermal element and the manufacturing method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1777963A (en) * 1929-02-20 1930-10-07 Owen Dyneto Corp Regulating system for variable speed dynamo-electric machines
US2045948A (en) * 1933-03-23 1936-06-30 Betty Hardison Thermal switch
DE1101644B (de) * 1958-09-10 1961-03-09 Licentia Gmbh Energieregler fuer elektrische Heizgeraete mit Mitteln zur Ausschaltung des Raumtemperatureinflusses

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2622677A (en) * 1947-12-19 1952-12-23 Pierre L Caffier Electrical interval timer
US2936354A (en) * 1959-06-03 1960-05-10 Vericontrol Associates Temperature compensated thermal power relay

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1777963A (en) * 1929-02-20 1930-10-07 Owen Dyneto Corp Regulating system for variable speed dynamo-electric machines
US2045948A (en) * 1933-03-23 1936-06-30 Betty Hardison Thermal switch
DE1101644B (de) * 1958-09-10 1961-03-09 Licentia Gmbh Energieregler fuer elektrische Heizgeraete mit Mitteln zur Ausschaltung des Raumtemperatureinflusses

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4307367A (en) * 1980-04-15 1981-12-22 Magic Chef, Inc. Bi-stable relay
US4481494A (en) * 1983-01-31 1984-11-06 Therm-O-Disc, Incorporated Bi-metal snap disc operated relay
US20140166639A1 (en) * 2011-08-03 2014-06-19 Schneider Electric Industries Sas Bimetal thermal element and the manufacturing method thereof
US10368398B2 (en) * 2011-08-03 2019-07-30 Schneider Electric Industries Sas Bimetal thermal element and the manufacturing method thereof

Also Published As

Publication number Publication date
DE1301859B (de) 1969-08-28
DE1283392B (de) 1968-11-21
GB1165167A (en) 1969-09-24
DK126458B (da) 1973-07-16
CH450551A (de) 1968-01-31

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