US2815417A - Thermostat - Google Patents

Thermostat Download PDF

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Publication number
US2815417A
US2815417A US641112A US64111257A US2815417A US 2815417 A US2815417 A US 2815417A US 641112 A US641112 A US 641112A US 64111257 A US64111257 A US 64111257A US 2815417 A US2815417 A US 2815417A
Authority
US
United States
Prior art keywords
strip
bimetallic
switch
stationary contact
casing
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
US641112A
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English (en)
Inventor
Lenoir Michel
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.)
PETERCEM SA
Original Assignee
PETERCEM SA
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 PETERCEM SA filed Critical PETERCEM SA
Application granted granted Critical
Publication of US2815417A publication Critical patent/US2815417A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/275—Control of temperature characterised by the use of electric means with sensing element expanding, contracting, or fusing in response to changes of temperature
    • G05D23/27535—Details of the sensing element
    • G05D23/2754—Details of the sensing element using bimetallic element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/04—Bases; Housings; Mountings
    • 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

  • This invention relates to electrical switches of the bimetallic control type and in particular to an improved construction for a switch of very small dimensions known as a miniature switch and which can be placed in normally quite inaccessible places where it may be left permanently to control the temperature there such as, for example, within an electrical coil or winding on a motor, or on the inside of a pipe of small diameter, etc.
  • the principal object of the invention is to provide a miniature sized bimetallic type of a reverser switch which has a small time constant, a means of adjustment or regulation to adjust the temperature at which the switch operates, and which is provided with a pair of stationary contact members between which a movable contact member operates, the movable contact member being controlled in accordance with the displacement of a bimetallic strip member as the temperature on the latter changes.
  • the invention is characterized by a very thin gauge elongated, metallic, electrically conductive casing and which also has a good heat conductive characteristic, and into which is slidable an assembly comprising a metallic support plate which carries a pair of spaced stationary contact members and an elongated elastic strip pressed endwise to take a curved form constituting a movable contact member which is placed between the stationary contact members.
  • One end of the elastic strip is attached to a support which is adjustable longitudinally along the support plate in order to adjust the compression on the elastic strip and the opposite end of the elastic strip is attached to the movable end of a generally U-shaped bimetallic member thus causing the curved strip to press its convexly curved surface against one or the other of said stationary contact members depending upon the amount of heat applied to the bimetallic member.
  • the elastic strip is caused to iiex rapidly from one convex position across dead center to another convex position even though the movement of the bimetallic member has no snap acting characteristic, and one leg of the bimetallic member over a greater part of its length lies adjacent, and bears constantly against, the inner face of the wall of the casing which surrounds the assembly thus providing accurate and fast heat transfer through the casing to the bimetallic member in response to a change in temperature of the device being monitored.
  • Fig. l is a side view in elevation of the improved bimetallic switch in accordance with my invention.
  • Fig. 2 is a top plan View of the switch shown in Fig. l;
  • Fig. 3 is a central vertical longitudinal sectional view taken on line Ill- III of Fig. 2;
  • Fig. 4 is a vertical transverse section taken on line V-IV of Fig. 3;
  • Figs. 5 and 6 are fragmentary views of the interconnecting end portions of two components of the switch
  • Fig. 7 is a diagrammatic view showing the forces involved in operation of the switch components.
  • Fig. 8 is a side View in elevation of the improved switch shown in Fig. 1 and with the ends thereof sealed.
  • the bimetallic switch in accordance with the linvention comprises a structural sub-assembly which includes a primary support member in the form of a generally rectangular elongated metallic plane plate 1 made of relatively thin gauge material and which preferably is electrically conductive.
  • the normal attitude of the plate is vertical and the upper and lower edge portions are bent inwardly at right angles to the plane of the plate so as to form horizontally extending lower and upper flanges 1a, 1b.
  • a tongue 1c is struck out from the plate, and which lies in parallel spaced relation to the upper flange 1b, and a conductor 2 with an insulation covering 3 is held tightly in the space between flange 1b and tongue 1c.
  • the inner end of conductor 2 is bent into a curved shape and forms one stationary contact member 2a of the switch.
  • the opposite end portions of the plate 1 are also bent inwardly to lie at right angles thereto and form vertical end iianges 1e and 1f.
  • the upper edge of the left hand flange 1e is spaced from flange 1b to permit passage of conductor 2 and its insulating cover 3, and the lower edge of the right hand flange 1f is spaced from ange la to permit passage of conductor 4 and its insulation cover 5.
  • the flat base portion 7a of a generally U-shaped support member 7 made of relatively thin gauge, electrically conductive metallic material, and which is adjustable longitudinally along the liange la by means of a pair of vertically spaced adjustment screws 8 which are threaded through the end flange le and engage the left upstanding leg 7b of the member 7.
  • the upper portion of the right upstanding leg 7c of member 7 terminates in an outwardly pointing V-shaped notch 7d and which is apertured at 7e at its apex as indicated in Fig. 5.
  • the latter view also shows the bending axes x-x and y-y of. this V-shaped end portion.
  • an elastic, elongated, electrically conductive metallic strip 9 Arranged for operation between the stationary contact members 2a and 4a is an elastic, elongated, electrically conductive metallic strip 9 and the latter forms the movable contact members of the switch.
  • the left end of strip 9 is provided with a tongue portion 9a shown in Fig. 6 and which is adapted to be received in the aperture '7e of support member 7 for oscillation about an axis y-y' normal to the plane of the plate 1.
  • the opposite end of the strip 9 is supported by the movable leg portion 10a of a generally U-shaped bimetallic strip member 10.
  • the lower ⁇ leg portion 10a which is free to move as the temperature changes terminates in a V-shaped notch 10b and which is apertured at 10c its apex to receive the opposite tongued end 9b of the elastic strip 9.
  • the notched portion b is similar to the notched portion 7d of the support member 7 and contains a similar axis y-y for oscillation of the corresponding end of the strip 9 as the bimetallic strip 10 shifts, when heated, from one position to another in a manner to be described in more detail later on.
  • the upper leg portion ltld of the bimetallic strip 10, and which is longer than lower leg portion ltla, is secured against movement by virtue of the fact that it is pressed tightly between the upper surface of tlange lb and the inner surface of the top wall of a casing 1li which is also made of relatively thin gauge, electrically conductive and heat conductive material, the top wall of the rectangularly configured casing 11 sliding in close engagement with the top face of bimetallic strip portion ltlrl, and the lower wall of casing 11 sliding in close engagement with the underface of the bottom flange 1a of the support plate 1.
  • the latter is provided with a centrally located pair of parallel spaced, transversely extending slots 1k into which an offset central portion ltle of the bimetallic leg portion 10d is entered, the said central, offset portion 10e thus underlying the ange lb for the distance therealong between the slots lk.
  • the lange 1b is spaced from the end liange 1f so as to enable the bimetallic strip to pass freely therebetween.
  • the amplitude of the movement of the under leg 19a of the bimetallic strip 10 is limited by the space between two tongues 1g and 1h also struck out from the back plate 1 and which lie on opposite sides of the bimetallic leg 10a in parallel spaced relation and parallel to the upper and lower flanges 1a and 1b,
  • the stationary contact members 2n and 4a may be insulated from the corresponding side of the outer casing 11, it will be seen from Fig. 4 that a thin mica plate 12 is inserted therebetween.
  • a conductor 13, soldered to the casing 11 is electrically connected to the left end of the elastic metallic strip 9 by virtue of the fact that the casing 11, plate 1 and support member 7 are all made from electrically conductive material,
  • a circuit will be completed between conductor 13 and conductor 4 or between conductor 13 and conductor 2 to thus form a reversing or inverter type of switch.
  • Fig. 7 indicates the operating principles which are involved.
  • z-z indicates the horizontal median plane between the stationary contact members 2a and au
  • m is the component, in such plane, of the compression or end force applied by the support member 7 to the end of the elastic strip 9
  • n and p are the components, normal to said plane, of the force exercised by the bimetallic strip ltl on the strip 9.
  • the strip 9 is compressed between its opposite end supports into a longitudinally curved Shape.
  • the curvature of strip 9 is along the line through the points owl and the central portion of the same is curved convexly into engagement with stationary contact member 2a.
  • the bimetallic strip 1t becomes heated, such as by the heat given ott from an electrical coil carrying a current overload and with which it lies in good heat transfer relation through the casinfy 11, the end of the strip 9 which was at the position z, under the action of upward force n transmitted by the end Mib of bimetallic strip 1li, shifts with the latter and comes to the position u.
  • the strip 9 is then aligned with points owu.
  • the strip 9 will be caused to abruptly disengage itself from stationary contact member 2a, and undergo a reversal of curvature so l as to bring it into quick engagement with the oppositely located stationary contact member 4a.
  • the strip 9 is then positioned along the line through the points ovr.
  • the distance tr corresponds to a course of travel of the movable end 10b of bimetallic strip 1t) and which is limited by the stop tongues 1g and lili.
  • an assembly comprising an elongated metallic support strip, a pair of stationary contact members mounted on said suppont strip -in spaced confronting relation, a lmovable contact member in the form of an elastic strip member disposed between said stationary Contact members, a longitudinally yieldable support member to which one end of said elastic strip is pivotally secured for oscillation about the pivot axis which is normal to the longitudinal axis of said elastic strip and a bimetallic strip mounted on said support strip, the opposite end of said elastic strip member being pivotally secured to an outer end of said bimetallic strip member for oscillation about the pivot axis which is parallel to the pivot axis of oscillation at the opposite end of said elastic strip member, said elastic strip member being held in a longitudinally curved attitude between the pivotal supports at the opposite ends thereof so as to engage one of said stationary Contact members, said outer end of said bimetallic strip being free to deflect in the plane of said elastic strip member with changes in temperature thereof so as to effect a like
  • a thermostatic switch as defined in claim 1 wherein said pressure adjusting means comprises a screw adapted to bear against said support member.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Thermally Actuated Switches (AREA)
US641112A 1956-03-15 1957-02-19 Thermostat Expired - Lifetime US2815417A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1145813T 1956-03-15

Publications (1)

Publication Number Publication Date
US2815417A true US2815417A (en) 1957-12-03

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ID=9645028

Family Applications (1)

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US641112A Expired - Lifetime US2815417A (en) 1956-03-15 1957-02-19 Thermostat

Country Status (5)

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US (1) US2815417A (enrdf_load_stackoverflow)
BE (1) BE553414A (enrdf_load_stackoverflow)
DE (1) DE1087669B (enrdf_load_stackoverflow)
FR (1) FR1145813A (enrdf_load_stackoverflow)
GB (1) GB798537A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1094847B (de) * 1958-10-16 1960-12-15 Alfred Odenwald Klein-Thermoschalter
US3087033A (en) * 1959-05-04 1963-04-23 Dales George Franklin Snap thermostat

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7308415A (enrdf_load_stackoverflow) * 1973-06-18 1974-12-20

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1797886A (en) * 1927-06-13 1931-03-24 Adolph A Thomas Electric thermostat
US2240625A (en) * 1939-11-29 1941-05-06 Maurice Richard J Fitz Heating pad
US2643311A (en) * 1951-06-22 1953-06-23 Comb Control Corp Thermal switch
US2767284A (en) * 1955-02-07 1956-10-16 Metals & Controls Corp Thermostatic switch

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL79469C (enrdf_load_stackoverflow) * 1951-04-10

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1797886A (en) * 1927-06-13 1931-03-24 Adolph A Thomas Electric thermostat
US2240625A (en) * 1939-11-29 1941-05-06 Maurice Richard J Fitz Heating pad
US2643311A (en) * 1951-06-22 1953-06-23 Comb Control Corp Thermal switch
US2767284A (en) * 1955-02-07 1956-10-16 Metals & Controls Corp Thermostatic switch

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1094847B (de) * 1958-10-16 1960-12-15 Alfred Odenwald Klein-Thermoschalter
US3087033A (en) * 1959-05-04 1963-04-23 Dales George Franklin Snap thermostat

Also Published As

Publication number Publication date
GB798537A (en) 1958-07-23
BE553414A (enrdf_load_stackoverflow)
FR1145813A (fr) 1957-10-30
DE1087669B (de) 1960-08-25

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