US2547171A - Snap switch - Google Patents

Description

R. E. PROUTY April 3, 1951 SNAP SWITCH Filed OCt. 3l, 1947 jizz/672 fr:

Patented Apr. 3, 1951 SNAP SWITCH Robert E. Prouty, Logansport, Ind., assignor to Essex Wire Corporation, Logansport, Ind., a

corporation of Michigan Application October 31, 1947, Serial No. 783,412

4 Claims.

' My invention relates, generally to circuit interrupters and it has particular relation to switches of the snap acting type. More specifically it relates to the provision of manually operable resetting means for the thermal relay disclosed in my copending application, Serial No. 783,411, led October 31, 1947, and assigned to the assignee of this application.

Among the objects of my invention are: To maintain a thermallyr operable overload protector relay in the operated position once it has operated in response to an overload; to reset such a relay to the normal operative position; to employ an actuator operating through a permanent magnet and carrying an armature for controlling the functioning of the relay contacts; to provide a self-closing switch that is manually operable to the open position; and to hold the switch in either the closed or open position by the cooperation of a pair of armatures and a permanent magnet and to move the same from one position to the other by manually operable push buttons.

' Other objects of my invention will, in part, be obvious and in part'l appear hereinafter.

My invention is disclosed in the embodiments thereof shown in the accompanying drawing, vand it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the constructions hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of my invention reference may be had to the following detailed description, taken together with the accompanying drawing, in which:

Figure 1 is a detail sectional View taken along the line I-I of Figure 2 and illustrating how the thermal overload relay disclosed in my copending application, above referred to, can be constructed so that it remains in the operated position when it has been operated in response to an overload and arranged to be restored to the original position by operation of a push button;

Figure 2 is a detail sectional view taken along the line 2-2 of Figure 1, showing the Switch construction in front elevation;

Figure 3 is a view, similar to Figure 1, but showing a self-closing switch employing a permanent magnet and an armature to control the operation of the switch contacts as permitted by a manually operable push button; and

Figure 4 is a view, similar to Figure l, showing 2 a magnetic control which is operative in either position of the switch contacts and which includes a pair of manually operable push buttons for operating the switch contacts in opposite directions.

Referring now particularly to Figures l and 2 of the drawings, it will be noted that the reference character I0 designates, generally, a resettable thermal overload protector relay in which the present invention is embodied. The relay IG can be employed, as described in my copending application above referred to, in conjunction with a motor starting relay for protecting the motor from being subjected to overloads. The relay le is constructed so as to require manual resetting once it has operated.

The relay I0 is provided with a housing or case I I of insulating material such as a phenolic condensation product. It has integrally formed foot portions I2 and a cover I3 formed of the same material and secured thereto by tubular rivets I4. Screw terminals I5, only one of which is illustrated in Figure l, are provided on the case II for making external connections to the relay Iii.

Within the housing or case I I there is located a support i6 of insulating material such as a phenolic condensation product, and it carries near one end a conductor strip I8 which may be connected to one of the screw terminals i5 by a lead I9 and to which may be secured a contact 20, preferably in the form of a silver button. The stationary Contact 2D is arranged to be engaged normally by a movable contact 2I also preferably a silver button. The movable contact 2| is carried by a spring 22 which may be an chored in cantilever fashion to a bracket 23 that in turn is secured to the support I6. The bracket 23 preferably is constructed as described in detail in my said copending application and is provided with an adjusting screw 24 which serves to change the biasing force exerted by the spring 22 as will be understood readily.

In order to move the spring 22 for the purpose of separating the contacts 2Q and 2l an actuator 2G is employed in the form of a pin of nonmagnetic material such as aluminum. The actuator 26 is slidably mounted in an aperture 2'! in a generally rectangularly shaped permanent magnet 28 having an Ii-shaped cross section which provides poles 28 and 3G at opposite ends. The magnet 28 is positioned in a generally rectangular opening 3i in the support I8 and is secured in position thereon by plates Si on oppo site sides which are held in place by rivets 33.

v'net' 28.-

At the ends of the actuator 26 stop members 34 and 35 are provided. The stop members 34 and 35 both may be formed of magnetic material to provide armatures for cooperating with the permanent magnet 2d. As shown, they are in the form of circular Washers. Alternatively the stop member 312 may be formed of non-magnetic materialf'an'dl'the stop member .e5 of magnetic material.

The actuator 2e may be moved by a biinetallic strip 38 which is anchored in cantilever fashion to a bracket 3s that is similar to the bracltettzl but on the opposite side o the support iS, as illustrated. An adjusting screw ille serves "to adjust the biasing force applie'dfby tlfiefstrip and to change its calibration. I-Ieat may be supplied to the bimetallic stripjts by .a heater element 4i whose terminals are secured to conducting sleeves 42 and i3 that project-f through the support I6. The sleeve ft2 serves in part to 'secure 'the brackets T23 'and llfto the support le. It alsointeifconneot's 'the contactst and El .and thieheater el rit' il f1 :"series'circuit relation a's shown f clearly in 'my 1 application above referred to. Suitable are provided for" interconnecting the lccnductorv strip i5 andfthe sleeve'ri to the'external screw Iterminals l5.

, yOnce the*actuator"2i*1 hasbeen the bimetallic. strip .de to fopen. the contacts le and 2l,- the actuator'ildremains in theep'erated position since-'the armatures is held adjacent the 'polesv 29 and *to of the permanent magneti. When this' Yoccurs it `is. necessary to provide external means for'. restoring tnezactuator 2e to the initial position pen t the spring Z2 to again close the contacts and For .thispurpose"alpusnputton N i=V iidanly mounted in'asuitable aperture il ie housing or case v'H1 A spring die, held by a rivet serves to bias the push butto-neil' to its outermost posi* tion.

In operation, on the `occurrence ofoverload asa result of whiclisunicicntheat is ap d to the bimetallic strip 33 to move the actuator Sulioiently'toopen the contacts E@ v'and 2'with fa `snap "action, :the circuit th qvoth-mugli is 'opened andas the relay' it is con. cted :in series with 'a motor or like 'electric "evice', theener igizing circuit thereto' .is op d. While heat no 'longer applied to 'the vb'iinetallie strip "3S andV iin-returns to its initialposition,V the actuator 2e' remains in the'. oper .ed position by' thefattraction of thestop bei or armature 35 to' the permanent magno rIi the stop me, is also formedoi magnetic:materialthe.:l appreciable time delaybeiore the actuator 2tl `is moved'by the birnetallic stript over thatwhlieh is provided Whenfthe stop" niemberfii is formed of non-magnetic material. 'By depressing the pushV button. 46 either manuallycr by at machine part, .the actuator 21e islr. vt. so as torsepae rate the armature ''froin the'permanent mage The contacts 2t and 2i are then permitted to reclose with a snap action and the circuit therethrough is reestablished.

Looking now at Figuresf and l of the drawings' it will be observed'tha't twomo'diiied switches are illustrated therein, neither of'vvh-ich constitutes part of my herein 'claimed invention but "this position by the spring 22.

parts used in the switch construction shown in' Figures 1 and 2 and described hereinbefore. It will be observed that the contacts 2i! and 2| and the spring 22 are located on the opposite side of the support I5 in Figure 3. Also the stop memberr 34 is in the form of a non-magnetic washer While the stop member 35 is of magnetic material and'rcoi-istitutes an armature for cooperation with the permanent `magnet-28.` As before the contacts 20 and 2l are normally closed and held in When the push button 46 is depressed suiciently to engage the adjacent end of the actuator 2t, it is moved to .f in turn move the A.spring 22 and separate the -eoritae'ts-f IandrZl with a snap action. When fthepush"tmttori T45" is released, the biasing force ofthe spring-22and the magnetic attraction between the permanent magnet 28 and the stop member or armature 35 serves to move actuator 26 to the left and closeA contacts 2G and 2I with afsnapy action, thereby restoring the'lswitch I5Ito the initial condition.- shown inthe drawing.y

In AligureL atmechanicalswitch is illustrated,

generally, at 55. This-switch employs certain of the details shown lin' Figures 1 and 2 and-described hereinbefore. The mechanical-switchv is so Yconstructed that the contacts 2li and2l are held in either theopenory the, closed position and the application of an external force is .required for operating them vinopposite directions. :In this construction-both of the stop membe1's34 andz areformed of magnetic material. Aseoond push button 56 is `provided and slidably mounted in'anfaperture 5l in the cover I3.- `vThe .push button et" is vcarried by a-spring strip 58 which .is :secured by ari-vet y5G to thefcover' J3. The -springe serves to restore'th'eA push-button 56 tothe position shown in the drawing'when the pressure applied thereto is removed.

When vthe switch is positioned .asshown in Figure 4, the applicationof sufficient pressure .to ,the push button l-5 moves the actuator '2S-to ythe right. This separates the stop'memberlorarmature v35 from the permanent magnet 2,;8 andcauses the spring l22'to move .the Vcontact 2t laway vfrom the stationaryfcontaet .2d with aA vsnapl action. The s-top member or arma-ture St is movedpartly as av result ofthe movement of the push button '46 and partly as afresultiof attraction by -th'eperf4 .marient magnet 28.- It is held againsttheperf marient magnet 2t and the .contacts 2l] and-2| remain separate'dfater .the pressure applied to the push button 46 is removed.

Now when pressure is applied tothe other push button SGVitmoves the spring 22 and the actuator 26 tothe original position shown in the drawing Where the-contacts 2% and. 2l are closed with a snap action and remain in the 'closed position.

Sincer certain `further changes can be made, lin the foregoing constructions and diierent embodiments of the invention can be made without departing from the spiritf'and scope thereo-itfis intended that all matter shownl in theiacconie panying-v drawing and. describedhereinbetore' shall cev interpret'ed'as illustrative and not ina limlit'ng sense.

Ifclaim asmy invention.: .l

1. in a switcnwincombination, a single'walll support, a bracket fastened to said support, a'leai spring secured canti-lever fashionat one 'end tosaid bracket so as-'t'o'lie along one side but spaced from. said support, a pair of contacts one being stationarily mounted and the' other' being mounted at the-other'end of said spi-ing? "for movement therewith and relative to the one contact, a permanent magnet having an aperture therein mounted in said support, a non-magnetic actuator slidingly journalled in the aperture of said magnet transversely of said support, an armature carried by said actuator and movable therewith toward and away from said magnet, a bimetallic blade engageable with said actuator slidingly to move the latter relative to said magnet, said actuator being engageable with said spring to effect resilient movement of the latter and of said other contact relative to said one contact, and a push button for moving said actuator through said magnet.

2. In a switch, in combination, a single wall support, a bracket fastened to said support, a spring secured in cantilever fashion at one end to said bracket, a pair of contacts one being stationarily mounted and the other being mounted at the other end of said spring for movement therewith and relative to the one contact, a permanent magnet having an aperture therein mounted in said support, a non-magnetic actuator slidingly journalled in the aperture of said magnet transversely of said support, an armature carried by said actuator and movable therewith toward and away from said magnet, said actuator cooperating with said spring to effect movement thereof and of said other contact relative to said one contact, means disposed on one side of said support selectively engageable with one end of said actuator for manually effecting axial movement of said actuator in one direction, and additional means disposed on the other side of said support adapted periodically to engage the other end of said actuator for initiating electrically responsive axial movement of said actuator in the opposite direction.

3. The switch as set forth in claim 2 wherein the rst said means comprises a manually operable push button and the other of said means comprises a bimetallic element.

4. In a device of the class described, a support member of insulating material, a pair of resilient elongated leaf members mounted in spaced relation at one end and on opposite sides of said support, each being mounted in cantilever fashion, one of said leaf members being of thermally responsive bimetallic material and both of said leaf members having their free ends adapted for arcuate movement toward and away from said support; a pair of contact members mounted in 6 registering relationship, one on said support and one on said actuately movable free end of said other leaf member which is non-bimetallic; a permanent magnet housed in said support between said two leaf members, said magnet having an aperture formed axially therethrough and disposed transversely of said support, a nonmagnetic actuator slidingly journalled in said aperture for reciprocal sliding movement therein through said magnet and support between said two leaf members, a magnetic armature mounted on one end of said actuator between said support and said bimetallic leaf member, an insulator stop mounted on the opposite end of said actuator between said support and said other leaf member whereby said actuator will move in a single direction in response to magnetic attraction of said magnet for said armature; manually operated push button means disposed adjacent said insulator, but on the opposite side of said other leaf member therefrom and adapted for sliding movement toward and away from said other leaf member, said insulator stop and said actuator; and said armature being movable into said magnets attractive field in response to thermally imposed arcuate movement of said bimetallic leaf member which movement of said armature causes said actuator to contact said other leaf member to cause a biasing movement thereof away from said support to separate said two contacts.

ROBERT E. PROUTY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,973 Kurtz Feb. 10, 1948 1,859,985 Riedel May 24, 1932 2,145,950 Persons Feb. 7, 1939 2,213,890 Schaefer Sept. 3, 1940 2,313,597 Stimson Mar. 9, 1943 2,339,087 Mantz Jan. 11, 1944 2,388,951 Bower Nov. 13, 1945 2,410,055 Frerer Oct. 29, 1946 FOREIGN PATENTS Number Country Date 536,701 Great Britain May 23, 1941

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