US3103568A - Thermally responsive switch devices - Google Patents

Thermally responsive switch devices Download PDF

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Publication number
US3103568A
US3103568A US3103568DA US3103568A US 3103568 A US3103568 A US 3103568A US 3103568D A US3103568D A US 3103568DA US 3103568 A US3103568 A US 3103568A
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lever
housing
movement
axis
spring
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/24—Switches operated by change of fluid pressure, by fluid pressure waves, or by change of fluid flow
    • H01H35/26—Details
    • H01H35/2607—Means for adjustment of "ON" or "OFF" operating pressure

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  • FIG. 7 INVENTORS JOHN LIEBERMANN THOMAS l. SYFERT CLYDE K. STORER JAMES M.CROWLEY Sept. 10, 1963 .1. LIEBERMANN ETAI. 3,103,568
  • a snap acting switch mechanism embodies a snap acting switch mechanism, a thermally responsive power element for operation thereof, and adjustable means for varying the operating characteristics of the switch device.
  • Electric switch devices of the type with which the invention is concerned are particularly suited for use in the thermostatic control of refrigerators, air-conditioners and the like apparatus, wherein an electric compressor motor is cyclically operated in response to temperature variations in the apparatus or in the medium being heated or cooled.
  • the temperature variations to which the switch devices must respond "differ with each apparatus and often with each application of the same type of apparatus.
  • the space which may be occupied by a switch device is at a premium.
  • Still another object of this, invention is the provision of the toggle member and the bellows engaging lever in theform of bell cranks arranged so as to define a space therebetween for accommodating the adjusting lever and range spring, the bell cranks being pivoted aboutparallel axes and arranged with one leg of each extending toward but terminating short of one leg of the other bell crank with the over-center spring means disposed therebetween, and the other leg of each bell crank extending substantially parallel to and in the same direction as that of the other bell crank so as to define the mentioned space between the parallel legs thereof.
  • Another object of the present invention is the provision of improved switch means embodying theforegoing constru'ctions and in one form of which the cut-out and cut-in temperature characteristics may be simultaneously varied by a single control, and in another form of which one of those temperature characteristics is maintained constant although the other is varied.
  • the invention aims to provide other constructions and arrangements of parts, the objects and advantages of which will become apparent from the following description of the preferred embodiments of the to .be maintained by a refrigerator, air conditioner, or
  • this invention aims to provide an improved thermally responsive switch device of the above mentioned character in which certainnovel constructions andarrangements of parts providethe aforementioned desirable features, the device comprising a generally rectangular housing formed at least in part by an insulator member located at one end thereof and which carries a movable switch contact and a fixed contact, the movable contact being actuated for cooperation with the fixed contact by a toggle member in the form 'of a lever arm pivoted to the insulator memberfand extending alongside thereof and being connected with the movable" device having the above described arrangement of parts and wherein the snap acting mechanism may be conveniently and accurately adjusted to select the-temperatures invention and from the accompanying sheets of drawings forming a part of this sepcification, and in which:
  • FIG. 1 is a perspective view of a thermally responsive switch device embodying this invention
  • FIG. 2 is another perspective view of the device of FIG. 1
  • a a FIG. 3 is a section-a1 'view of the switch device taken substantially along line 33 of FIG. 1 and on an enlarged scale;
  • FIG. 4 is a view similar to FIG. 3 but with some parts in different positions;
  • PIG. 5 is a sectional viewtaken substantially along FIG. 1;
  • FIG. 7 is a sectional view taken along line 7-7 of F iG.3;and
  • FIG. 8 is a sectional view similar to FIG. 3 but illustrat-;
  • thermoly actuated electric switch device generally indicated at 10,
  • the switch device 10 includes a housing comprising I a channel shaped member 1:1,preferably formed of sheet metal, and comprisingsidewalls 11a, 11b joined by a wall 110.
  • An insulator member 12, formed of molded Bakelite or other suitable insulating plastic material extends from between the walls 11a, 11b of channel member 11 so as to form one end portion of the housing.
  • insulator member 12 comprises an end wall 12a, side walls 12b and 120, and a bottomwall 12d, and is conveniently secured in place by lugs 122 extending through at which the switch contacts will be operated between open I and closed positions, the mechanism including, a bellows engaging lever pivoted in thehousing for movementabout one axis and connected by over-center spring means to the toggle member for effecting the snap action thereof,
  • The; housing is preferably closed on the side opposite wall by an insulating cover member 14 which is adapted to;-
  • a mounting bracket 15 having apertured ears I or lugs 15a, overlies wall 11b and is secured thereto by tabs 11d as shown.
  • AYcb iuc'mr member 16 extends through, and is secured in, an'opening in end wall12a of insulator member 12 andterniinatesat its outer end in a blade type terminal connector 16a.
  • -A flexible con-tact arm 17' isformed of fiatspring metalsuch'as beryllium copper and has an inturned end l7a secur'ed tothe inner end of conductor 15 by welding or the like'.
  • -Contact arm 17 carries a movand 20 when open.
  • a washer 36'0f nylon or other suitable materials urrounds screw 34 and serves to lock that screw in its adjusted position.
  • Conductor member 19 has two leg portions extending through, and secured in, openings in insulator 1 wall 12a-and terminating infblade type terminal connectors 19b and 19c Snap actingactuator means areprovided for operating contact arm 17 to bring contact 20 into and out of en-" gagement with contact 18 for making and breaking an elec- I l tric' circuit therethrough.
  • the snap acting mechanism comprises a toggle member 22, which is pivoted to insulator member 12, and a bellows operated lever 2s which will later bedescribed'in detaihhte toggle member and the lever being opera Lively interconnected by a C-s'haped over-center acting toggle spring 24;
  • togglemember 22 is molded from- Bakelite? or "other suitable rigid insulating material,
  • toggle member '22 takes the form of bell crank lever.
  • Leg 22a extends across insulator member 12 and termi-v nates in anoffse't portion 220 which projects between Rotation of lever 23 in :a counter-clockwise direction about the pivotal axis f defined by fulcrum pin 29 will move or bring the pivotal connection between spring end 245 and knife edge3 3 through a plane extending through fulcrum pin 29 and the pivotal connection of toggle member 22 with insulator member 12.
  • spring 24 will act against plate 22b of toggle member 22 causing the latter to rotate in a counter-clockwise direction into the position shown in FIG. 4 with a snap acting movement.
  • Lever 23 which is preferably formed as a sheet metal of a bell crank, and is pivotally connected to channel member 11 by'a triangular 'tfulc'rum pin 29 which extends between sidewalls 11a and 11b and passes through openings 30 in spaced.
  • bearing member 230 extending from leg 23b Legf23b and togglemember leg 22 1 ex- I tend substantially parallel tq one "another. and in the same direction, while-the plate-22b and leg 23a extend toward, but terminate shorto'f, one another.
  • a generally rectangular space is therebydefined between the toggle member 22 and-bellows lever 23,'which space is utilized to accommodatelother parts 1 ently be made apparent.
  • spring 24 acts against plate 22b of toggle member 22, .urging thelatter in a oloclowise'direction, as viewed in II th'e'draWingsQ-abQut the pivotal axis formed by knife edge 25 and grooves 26 so that-offset portion 220 holds 9 contact arm 17 with movable contact'ltl separatedfrom ,fixed'contactN. Movementof toggle member 22in this -dir e ction is limited by engagement of 'olfset portion 22c with a screw 34 which extends through a threaded openstamping, comprises leg portions23a and 23b extending.
  • 'Dhenmally responsive power means are provided for moving lever 23 about its pivot'pin' 29 for actuation of the switch mechanism and. in this i'nstance comprises an expansible bellows, generally indicated at 44 and having an axially extending post tti a in engagement with an adjust-ing screw 41 received in a threaded opening 23d in leg 23b of lever 23.
  • Bellows 40 forms part of an assembly comprising aniend plate 44 to which the bellows is secured as bybrazing and whichisin turn secured to side walls 11a, l-lb by tabs llle crimped thereover.
  • tubular member 46 extends: from end plate 44 and communicates therethrough with the interior of the bellows.
  • End plate 44 maybe conveniently provided with tongues 44b which serve to grip cover 14.
  • a tension spring 48 is disposed in the previously mentioned space between toggle member 22 and lever 23fand 1 is connected at one end 4811' thereof to a hook 4?, which is struck out from leg 23a of lever 23', and this spring serves to resiliently unge lever '23 in a clockwise direction about pivot pin 29 and against the post 40a of bellows ,threadedly engaged in a nut member 51 lodged in the I eonvolutions of spring 48, to an adjusting lever 52, in a i 40.
  • Spring 48 is connected at its other end by ascrew 50,
  • Lever'52 ' has spaced bearing portions 52aiextending thro'ugh slots 53 in housing side wall 11b and serving to pivotal-1y. connect the lever thereto for rotation about an axis extending transverselyof the of fulcrum pin 29.
  • Lever 52 is also provided with a cam following portion 52b extending therefrom and adapted to engage the periphe'ry of a rotatable cam '55.
  • Cam 55 is connected to a shaft 56 for rotation therewith, the, shaft being suitably journaled in an opening in wall 11b and being adapted to receive a knob, notshown,
  • Rotation of cam 55 serves, toadjustably position 1ever 52 for increasing or decreasing the tension of spring 48, and hence for-adjusting the load imposed on bellows 40.
  • ScrewStl may also be adjusted to vary the tension on spring 48 and serves to shift the range of temperatures which'may be selected by use of the cam 55.
  • Screw 50 may therefore be referred to as a range adjusting screw and spring 48 as a range spring.
  • Switch ineludes means whereby the contacts 18 and 20 may be maintained in an open condition regardless of increases in temperature.
  • cooperable hook members 58and 59 are provided on lever arms 23a and 52 respectively.
  • shaft 56 is rotated in a manner to bring the highest portion 55a of cm 55 to bear against cam follower 52b of lever 52, the latter is moved so as to bring hook member 59 into engagement with hook member 58.
  • Lever 23 is thereby restrained against movement by bellows 40 and contacts 18 and 20 will be held open regardless of temperature changes experienced by the tubular element 46. 7
  • a modified switch device which may be referred to as a constant cut-in and variable cut-out device. That is to say, rotation of control shaft 56 serves only to adjust the temperature at which the contacts 18 and 20 open. This is accomplished by keeping the tension on range spring 48 constant and varying the amount of movement of bellows 40 necessary to actuate the switch to open the contacts.
  • the tension'on range spring 48 is maintained constant by providing an off cam 55' on shaft 56 with a profile whichwill not shift cam follower 52b except when the V follower is engaged by the cam rise indicated at 55" so as to cause hook members 58 and 59 to hold the switch in the off position.
  • a out-out temperature selecting cam 65 is provided on shaft 56in addition to the off Cam 65 is disposed adjacent the inner surface of housing wall 11b and'the periphery thereof is'engaged by a lever arm 67 extending from toggle member 22 and conveniently formed as a part of plate 22b.
  • Arm 67 and cam 65 cooperate .to limit movement of toggle member 22 in a counter-clockwise direction and hence serve to adjustably determine the amount of movement of bellows 40 and lever 23 necessary to snap'the toggle member to its switch opening position and therefore to adjustably determine the cut-out temperature of the switch device. While in the FIG.
  • said device having housing means at least one portion of which comprises an insulator member forming one end of the housing, said insulator member also supporting a relatively fixed contact in said housing for cooperation with said movable contact arm, a snap acting mechanism in said housing including a toggle member pivoted to said insulator member for movement about a first axis between first and second positions for actuating said movable contact arm, a lever pivoted in said housing for movement about a second axis and connected to said toggle member by an over-center acting spring, a temperature responsive power element for moving said lever to effect snap movement of said toggle member between said first and second positions, adjustable biasing means urging said lever in one direction against said power element, said adjustable biasing means including a second lever pivoted to a wall of said housing for movement about an axis transverse to said second axis, spring means connecting said second lever and the first mentioned lever, and control means including a rotary cam engaging said second lever for positioning thereof to select said variable operating characteristic, and means connecting said toggle member and
  • control means comprises a second cam rotatable with the first mentioned cam
  • means connecting said toggle member and said control means comprises an arm extending from said to gle member and engaging said second cam.
  • a thermally responsive switch device of the character described having housing means at least one portion of which comprises an insulator member forming one end of the'housing, said insulator member supporting a movable contact arm in said housing, said insualtor member also supporting a relatively fixed contact in said housing for cooperation with said movable contact arm, a snap acting mechanism in the housing including a toggle member pivoted to said insulator member for movement about a first axis between first and second positions for actuating said movable contact arm, temperature responsive power means in said housing at the other end thereof for operating said snap acting mechanism, said snap acting mechanism comprising a lever pivoted in said housing for movement about a second axis and connected to said toggle member by an over-center acting spring, said lever being movable by said temperature responsive power means for effecting snap movement of said toggle member between said first and second positions, and adjustable biasing means including a second lever pivoted to a wall of said housing for movement about an axis transverse to said second axis and urging the first mentioned lever in one direction
  • a switch comprising first and second bell cranks mounted for movement about first and second axes respectively, each bell crank having one leg extending toward and terminating short of one leg of the other bell crank, each bell crank having its other leg extending parallel to and in the same direction as the other leg of the other bell crank to define a space therebetween, first spring means between said one leg of each bell crank for elfecting snap acting movement of said first bell crank between first and second positions upon predetermined rotative movement of said second bell crank, electrical contact means operable by the other leg of said first bell crank upon said snap acting movements to make and break a circuit therethrough, second spring means acting Lon said one leg of said second bell crank for biasing thereof in one direction of rotation, thermally responsive plower means acting on the other leg of said second bell erank- [for eflecting rotation "thereof in said other direction against the action oflsaidsecondspiring means,

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  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Thermally Actuated Switches (AREA)
US3103568D 1961-05-05 Thermally responsive switch devices Expired - Lifetime US3103568A (en)

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US10795161A 1961-05-05 1961-05-05

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3191669A (en) * 1962-05-21 1965-06-29 Dale E Johnson Automatic vehicle temperature control
US3223395A (en) * 1961-11-02 1965-12-14 Robertshaw Controls Co Clothes dryer control system
US3304395A (en) * 1965-07-29 1967-02-14 Gen Electric Condition responsive electric switch mechanism
US4144515A (en) * 1977-02-09 1979-03-13 Ranco Incorporated Adjustable condition responsive control
US6252492B1 (en) 1999-03-18 2001-06-26 James P. Frank Condition-responsive electric switch mechanism

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1654315A (en) * 1923-04-06 1927-12-27 Westinghouse Electric & Mfg Co Quick-acting thermal relay
US2158824A (en) * 1936-11-23 1939-05-16 Cutler Hammer Inc Circuit controlling device
US2188438A (en) * 1937-05-07 1940-01-30 Honeywell Regulator Co Switching mechanism
US2447895A (en) * 1944-10-28 1948-08-24 Philco Corp Alarm system for electric refrigerators
US2820121A (en) * 1956-03-21 1958-01-14 Ranco Inc Control apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1654315A (en) * 1923-04-06 1927-12-27 Westinghouse Electric & Mfg Co Quick-acting thermal relay
US2158824A (en) * 1936-11-23 1939-05-16 Cutler Hammer Inc Circuit controlling device
US2188438A (en) * 1937-05-07 1940-01-30 Honeywell Regulator Co Switching mechanism
US2447895A (en) * 1944-10-28 1948-08-24 Philco Corp Alarm system for electric refrigerators
US2820121A (en) * 1956-03-21 1958-01-14 Ranco Inc Control apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3223395A (en) * 1961-11-02 1965-12-14 Robertshaw Controls Co Clothes dryer control system
US3191669A (en) * 1962-05-21 1965-06-29 Dale E Johnson Automatic vehicle temperature control
US3304395A (en) * 1965-07-29 1967-02-14 Gen Electric Condition responsive electric switch mechanism
US4144515A (en) * 1977-02-09 1979-03-13 Ranco Incorporated Adjustable condition responsive control
US6252492B1 (en) 1999-03-18 2001-06-26 James P. Frank Condition-responsive electric switch mechanism

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GB955402A (en) 1964-04-15
DK103678C (da) 1966-02-07

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