US3312802A - Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits - Google Patents

Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits Download PDF

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Publication number
US3312802A
US3312802A US517580A US51758065A US3312802A US 3312802 A US3312802 A US 3312802A US 517580 A US517580 A US 517580A US 51758065 A US51758065 A US 51758065A US 3312802 A US3312802 A US 3312802A
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US
United States
Prior art keywords
strip
heater
channel
slits
heat
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
US517580A
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English (en)
Inventor
Jr William D Ryckman
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.)
General Electric Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Priority to US517580A priority Critical patent/US3312802A/en
Priority to GB50170/66A priority patent/GB1126647A/en
Priority to NL666617238A priority patent/NL155121B/xx
Priority to FR87083A priority patent/FR1503488A/fr
Priority to ES0335014A priority patent/ES335014A1/es
Priority to CH1867666A priority patent/CH456728A/de
Priority to DE1966G0048874 priority patent/DE1640197B2/de
Priority to BE691999D priority patent/BE691999A/xx
Priority to SE17946/66A priority patent/SE335374B/xx
Application granted granted Critical
Publication of US3312802A publication Critical patent/US3312802A/en
Priority to JP73067A priority patent/JPS4210005B1/ja
Anticipated expiration legal-status Critical
Assigned to BLACK & DECKER, INC., A CORP. OF DE reassignment BLACK & DECKER, INC., A CORP. OF DE ASSIGNS AS OF APRIL 27, 1984 THE ENTIRE INTEREST Assignors: GENERAL ELECTRIC COMPANY A NY CORP.
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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 electrically heated bimetallic strips and to electrical switches using these strips.
  • switches In the manufacture of electrical switches it has long been known to take advantage of. the fact that different metals have different coeflicients of thermal expansion. To this end, switches have been constructed wherein a bimetallic strip is influenced by changes in the room ambient temperature to cause deflection of the strip, and a contact carried by the strip is moved into or out of engagement with another contact in the switch depending on the ambient temperature surrounding the strip. It has also been known to provide auxiliary heating means to influence the temperature surrounding the bimetallic strip so that deflection of the strip can be controlled independently of room temperature. Many of the prior devices have utilized a heater comprising :a resistanc wire coiled in helical fashion around thebimetallic strip.
  • Anjobject of the present invention is to provide a bimetallic strip with improved means to facilitate secure mounting of an electrical heater thereon in effective heat transfer relationship between the heater and each of the different metals forming the strip.
  • a further object is the provision of a bimetallic strip with improved means to mount a heater thereon in such a manner that the mounting is not substantially affected by flexure of the strip in the region of the mounting so that the heater will remain securely attached to the strip both before and during the time when heat is supplied from the heater.
  • Another object is to provide a thermally responsive switch using an electrically heated bimetallic strip of the character described which is fast-acting in response to current flow in the heater, and wherein heat transmitted from the heater to components in the switch other than the strip with which it is associated is minimized.
  • I provide an improved. construction for securely mounting an electrical heater directly on a bimetallic strip for use in a thermally responsive switch.
  • the mounting arrangement comprises a channel which is defined by a plurality of aligned arcuate portions spacedaltemately 3,312,802 Patented Apr. 4, 1967 ice in opposite directions from the plane of the strip. Adjacent arcuate portions are separated from each other by a slit through the strip so that an electrical heater may be inserted through the slit and confront each of the metals forming opposite surfaces of the strip. Thus, any tendency of one portion to move away from the heater under influence of heat is counteracted by the tendency of an adjacent portion to move toward the heater.
  • FIGURE 1 is a partial perspective view of a switch accordance with the present invention.
  • FIGURE 2 is a perspective view of a preferred embodiment of a bimetallic strip and electrical heater.
  • FIGURE 3 is a side view of the strip of FIGURE 2.
  • a thermally responsive switch 10 comprising a housing 11 which is preferably formed of moldable plastic and includes a base 11a and a cover 1112. Bimetallic strips 12 and 13, which deflect under the influence of heat, are spaced from each other at one end, 14 and 15 respectively, through the medium of electrically insulating blocks 16.
  • the assembly, including the blocks 16 and the strips 12 and 13, is attached to the base, and other blocks 17 may be used if it is necessary to insulate the other surfaces of the end of the strips from the base. So that the strips may have freedom of movement either in unison or one with respect to the other under the influence of heat, the interior of the housing is hollow.
  • the strips carry electrical contacts 21 and 22 respectively, and these cont-acts are adapted to be engaged with each other to permit electrical current to flow through the strips when the switch is on.
  • the contacts may be connected to the strips such as by riveting, welding or the like.
  • All electrical heater 23 is intimately associated with the bimetallic strip 12 in a manner to be described later in more detail. This electrical heater is for supplying auxili-ary heat to the strip 12 when it is desired to deflect the strip 12 with respect to the strip 13.
  • the bimetallic strips do not deflect relative to each other unless auxiliary heat is being supplied by the electrical heater.
  • the contact 22 on the strip 13 is on the surface of the metal having a low coeflicient of thermal expansion; while the contact 21 on the strip 12 is on the surface of the metal having a high coeflicient of thermal expansion.
  • the switch further includes electrical conductors for supplying electrical current through the strips-t0 the contacts 21 and 22, and for supplying current to the electrical heater 23.
  • I have provided conducting lugs 24 and 25 on the ends of the bimetallic strips for connection across electrical power lines 26 and 27; and I have provided conductors 28 and 29 which lead from oppositeends of the heat-er to a terminal board 30 on the switch, thence across power lines 31 and 32.
  • the thermostatic switch of FIGURE 1 operates in the following manner: Line switches 33 and 34 are open and there is no current flowing through either the heater 23 or a load device 35, and the thermostatic switch contacts 3
  • the heater supplies heat primarily only to the bimetallic strip 12. Under the influence of the heater, the strip 12 is rapidly heated to a greater extent than strip 13 thereby causing the contact 21 to move out of engagement with the contact 22 as a result of deflection of the strip 12 relative to the strip 13.
  • any suitable means, manual or automatic may be used to open and close the line switches 33 and 34.
  • the electrical circuit illustrated at FIGURE 1 is by. way of illustration only. In certain instances, such as when cyclical operation is desired, the electrical heater may be connected in series connection with the load and supplied with power from the same power source as is connected across the switch.
  • My preferred embodiment of a bimetallic strip 12 as illustrated in detail at FIGURES 2 and 3, presents a top surface 36 of a metal having a different coefiicient of thermal expansion than the coefficient of thermal expansion of the metal forming the bottom surface 37.
  • the strip has a pair of parallel slits 38 and 39 extending therethrough'.
  • a first integrally formed portion 40 is curved upwardly in an arcuate pattern spaced above the top surface 36 and extends from the slit 38 to one side edge 41 of the strip.
  • a second integrally formed portion 42 with a facial contour similar to the first is formed by curving the material of the strip between the slits downwardly below the bottom surface 37.
  • a third integrally formed portion 43 similar to the first extends between the slit 39' and the opposite side edge 44 of the bimetallic strip. These integrally formed portions thereby define 'a channel 45 extending transversely across the strip and having an axis through the slits.
  • the cross sectional configuration of the channel taken as a whole may be said to be generally circular.
  • the distance between the two slits 38 and 39 is approximately equal to the distance between the slit 38 and side edge 44 plus the distance between the slit 39 and side edge44 for a reason which will hereinafter be pointed
  • the electrical heater 23, in the form of a molded composition resistor of general cylindrical configuration, is snugly positioned in the channel 45' and preferably extends across the entire width of the bimetallic strip 12.
  • the heater should be located at an optimum point along the length of the bimetal to obtain maximum deflection for a given amount of heat supplied.
  • This optimum point is a function of such characteristics as heat loss at the ends of the bimetal, heat losses from the surfaces, and the shape of the bimetal. I have found that for the bimetal strip illustrated, this optimum point is from onefourth to one-third of the distance from the fixed end 14 to the free end 18.
  • the heater is in surface contact'with the top surface of the bimetallic strip 12 in the area of the second integrally formed portion 42, and is in surface contact with the bottom surface of the bimetallic strip in the area-of the first and third integrally formed portions 40 and 43 respectively.
  • the electric heater is coated with a material which is electrically insulating and thermally conducting
  • the heater may be held in position by frictional contact engagement with the surfaces forming the channel; however, in certain instances, it may be desirable to use a thermally conducting adhesive material to aid in holding the resistor in place and further aid in transmitting heat between the contacting surfaces. In case the heater does not occupy the entire volume of the channel it may be desirable to fill the unoccupied portions with a thermally conducting ma terial such as silicone grease to enhance thermal transfer to the surfaces confronting the channel.
  • a thermally responsive switch element comprising:
  • a bimetallic strip carrying a first contact adapted to be engaged with a second contact in the switch, said strip including a plurality of integrally formed channel-defining portions separated from each other by slits and spaced alternately in opposite directions from the top and bottom surfaces of the strip;
  • an electrical heater securely mounted on said strip in said channel, a first surface portion of said heater confronting the top surface of said bimetallic strip in one of said channel-defining portions, and a second surface portion of said heater confronting the bottom surface of said bimetallic strip in an adjacent one of said channel-defining portions.
  • a thermally responsive switch element comprising:
  • a bimetallic strip carrying a first contact adapted to be engaged with a second contact in the switch and having a pair of spaced parallel slits extending through top and'bottom surfaces thereof, said strip including first, second and third integrally formed portions spaced alternately in opposite directions from the surfaces of the stnp and defining a channel having an axis through said slits;
  • a thermally responsive switch comprising:
  • a bimetallic strip secured at one end to said housing and being free to deflect at the other end, and including a plurality of aligned arcuate integral portions separated from each other by slits through the strip and spaced alternately in opposite directions from the surfaces of said strip, said arcuate portions thereby defining a channel;
  • a thermally responsive switch comprising:
  • a switch assembly including first and second deflectable bimetallic strips spaced from each other in said housing and connected-thereto at one end of the strips, the opposite end of the strips being free to move within the housing, said first and second strips having similar deflection properties and positioned to deflect in the same direction under the influence of heat, and said first strip including three aligned arcuate integral portions separated from each other by slits through the strip and spaced alternately in 0p- 6 posite directions from the surfaces of said strip and thereby defining a channel through said strip;

Landscapes

  • Thermally Actuated Switches (AREA)
US517580A 1965-12-30 1965-12-30 Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits Expired - Lifetime US3312802A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US517580A US3312802A (en) 1965-12-30 1965-12-30 Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits
GB50170/66A GB1126647A (en) 1965-12-30 1966-11-09 Improvements in or relating to thermally responsive switch elements
NL666617238A NL155121B (nl) 1965-12-30 1966-12-08 Bimetalen strook.
FR87083A FR1503488A (fr) 1965-12-30 1966-12-12 Bilame à chauffage électrique
CH1867666A CH456728A (de) 1965-12-30 1966-12-28 Bimetallstreifen mit einem elektrischen Heizelement
ES0335014A ES335014A1 (es) 1965-12-30 1966-12-28 Un dispositivo de lamina bimetalica que lleva un primer contacto destinado a aplicarse con un segundo contacto de un interruptor electrico.
DE1966G0048874 DE1640197B2 (de) 1965-12-30 1966-12-29 Bimetallschalter
BE691999D BE691999A (enrdf_load_stackoverflow) 1965-12-30 1966-12-30
SE17946/66A SE335374B (enrdf_load_stackoverflow) 1965-12-30 1966-12-30
JP73067A JPS4210005B1 (enrdf_load_stackoverflow) 1965-12-30 1967-12-27

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US517580A US3312802A (en) 1965-12-30 1965-12-30 Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits

Publications (1)

Publication Number Publication Date
US3312802A true US3312802A (en) 1967-04-04

Family

ID=24060384

Family Applications (1)

Application Number Title Priority Date Filing Date
US517580A Expired - Lifetime US3312802A (en) 1965-12-30 1965-12-30 Bimetal with heater mounted through a channel formed by alternately spaced portions separated by slits

Country Status (10)

Country Link
US (1) US3312802A (enrdf_load_stackoverflow)
JP (1) JPS4210005B1 (enrdf_load_stackoverflow)
BE (1) BE691999A (enrdf_load_stackoverflow)
CH (1) CH456728A (enrdf_load_stackoverflow)
DE (1) DE1640197B2 (enrdf_load_stackoverflow)
ES (1) ES335014A1 (enrdf_load_stackoverflow)
FR (1) FR1503488A (enrdf_load_stackoverflow)
GB (1) GB1126647A (enrdf_load_stackoverflow)
NL (1) NL155121B (enrdf_load_stackoverflow)
SE (1) SE335374B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3621432A (en) * 1970-04-27 1971-11-16 Itt Thermostat
US4339741A (en) * 1980-10-31 1982-07-13 Ray William A Thermally actuated time delay switch
US5298876A (en) * 1993-04-30 1994-03-29 Gte Products Corporation Bi-metallic switch element
US20070081286A1 (en) * 2005-10-12 2007-04-12 Jones Thaddeus M Electrical receptacle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU1191683A (en) * 1982-03-03 1983-09-08 Paul Raymond Goodwin Electrically heatable differential thermal expansion devices
DE3231136C2 (de) * 1982-08-21 1984-08-23 Limitor AG, 8022 Zürich Bimetallschutzschalter

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2520906A (en) * 1946-06-22 1950-09-05 Photoswitch Inc Thermal microswitch
CA977480A (en) * 1970-01-19 1975-11-04 Franklin E. Bitting Solvent reactivatable neoprene resin based adhesive composition

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2520906A (en) * 1946-06-22 1950-09-05 Photoswitch Inc Thermal microswitch
CA977480A (en) * 1970-01-19 1975-11-04 Franklin E. Bitting Solvent reactivatable neoprene resin based adhesive composition

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3621432A (en) * 1970-04-27 1971-11-16 Itt Thermostat
US4339741A (en) * 1980-10-31 1982-07-13 Ray William A Thermally actuated time delay switch
US5298876A (en) * 1993-04-30 1994-03-29 Gte Products Corporation Bi-metallic switch element
US20070081286A1 (en) * 2005-10-12 2007-04-12 Jones Thaddeus M Electrical receptacle
US7480123B2 (en) * 2005-10-12 2009-01-20 Msx, Incorporated Electrical receptacle

Also Published As

Publication number Publication date
NL6617238A (enrdf_load_stackoverflow) 1967-07-03
CH456728A (de) 1968-07-31
NL155121B (nl) 1977-11-15
ES335014A1 (es) 1967-11-16
DE1640197B2 (de) 1976-12-30
GB1126647A (en) 1968-09-11
DE1640197A1 (de) 1970-12-03
BE691999A (enrdf_load_stackoverflow) 1967-05-29
SE335374B (enrdf_load_stackoverflow) 1971-05-24
JPS4210005B1 (enrdf_load_stackoverflow) 1967-05-26
FR1503488A (fr) 1967-11-24

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Legal Events

Date Code Title Description
AS Assignment

Owner name: BLACK & DECKER, INC., 1423 KIRKWOOD HIGHWAY NEWARK

Free format text: ASSIGNS AS OF APRIL 27, 1984 THE ENTIRE INTEREST;ASSIGNOR:GENERAL ELECTRIC COMPANY A NY CORP.;REEL/FRAME:004349/0275

Effective date: 19840824