US2616005A

US2616005A - Electric switch

Info

Publication number: US2616005A
Application number: US200976A
Authority: US
Inventors: Harry C Swan
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1950-12-15
Filing date: 1950-12-15
Publication date: 1952-10-28
Anticipated expiration: 1969-10-28
Also published as: DE1674630U; GB696269A; FR1046340A; DE901073C

Description

0ct. 28, 1952 H. c. SWAN 56,005

ELECTRIC swgTcH Filed nec. 15, 195o 2 SHEETS-SHEET 1 H. C. SWAN ELECTRIC SWITCH Oct. 28, 1952 Filed Dec. 15, 195o 2 SHEETS-SHEET 2 Patented Oct'. 28, 1952 UNITED STATES PATENT QFFICE' ELECTRIC SWITCH Y Application Decemherr1'5, 1950, Serial,No. 200,976

8 Claims;r

This invention relates to an electric switch-operative to control twol electrical circuits inaccordance with the current ow therethrough.

It is amongV the objects of the presentV invention to provide a thermoelectric switch having all of the characteristics of the switch disclosed-in the patent to Werner, No. 2,242,769, issued May 20,1941, but differing in construction, resulting in a much smaller switch which permits it to be mounted within the frame of the electric motor it is adapted to control, thereby eliminating the addition of undesirable housing provisions Ywhich destroy the symmetry of the motorand ruin its appearance.

Reducing the size of the switch not only substantially reduces its cost of manufacture, butv ing drawings Whereina preferred embodiment of the present invention isclearly shown.

In the drawings:

Fig. 1 is a plan view of the switch shown in full contact making position.

Fig. 2 is a view similar to Fig. l, showing the switch in a position in which one ofits circuits is broken and the other maintained.

Fig. 3 is a similar View of the switchshowing both of its circuits broken.

Fig. 4 is an end View of the switch.

Fig. 5 is a perspective view of the switch sans the insulating plate which carries the stationary contacts and upon which the switch is mounted.

Fig. 6 is a side view of the switch looking in the direction of arrow 6 of Fig. 4.

The plate upon which the switch is mounted maiT be of any suitable insulating material and for purposes of illustration, the present switch is shown made of a transparent synthetic-insulating compound through which the switch mechanism maybe viewed. This insulating base has two stationary contacts 2| and 22 mounted thereupon in any suitable manner and in'proper relative positions one to the other. The switch mechanism consists of a rigid frame 23, U-shaped for a portion of its length, which portion consists of the top web portion 24 and two depending side portions 25 and 2li having ears 2l and 28 respectively which extend through the insulatingv base 20 and are twistedso asto rigidly lock the:-

frame-to the-base-20. Frame23has Vtwo angular-- substantially atV right:-

projections 30 and 3| angles to -the web portion 24 thereof. The angular projection 3%- of` the rigid-frame 231hastwo-` ilexible contact'blades-32 and' 33 secured thereto with a spring 34 sandwiched therebetween. These. superposed

elements

32, 34 and 33 are anchored.

to the projection 30" by meansA of a rivetl 35;-

Blade spring-32 at its free-end, or more particu-- larlythe end thereof oppositeits anchored tend;

has a contact element 37| attached thereto whichi is adapted to cooperate withthe-stationary contact 2| to make-and'break afcircuit. Likewise;

trallyslotted portions in the two contac-tcarrying flexible blades 32 and33. The Fig. 5clearlyillustrates `the slot 4| in the-exible blade-33, this slot 4| being identical toslot 42-inthe-exible blade 32 asshown Fig.v 5. The abutment Mlissecured to spring 34 bymeans of a projection 43 on the abutment which-extends through an opening-in the spring-34v andis rivetedoverI the: spring. It willbe noted thatthe abutment 40` is mounted edgewise upon spring 34' and-is substantially at right angles thereto so that said] abutment moves transversely or edgewisefthroughthe slotted iiexible contactv carryingblades-32 'and 33.; The one end of the abutmentjdil'; more particularly the endthereofadjacentfto its point of,4

anchor to spring-34, has one-endjof the thermoelectric` elementl 5|)H secured thereto -so` as yto be in electrical connectiontherewith. The otherv end of this thermoelectric element is secured to an adjustable-.member l5| insulatingly--supportedLA upon the frame projection 3| by an insulating coil 52. Normally the-spring 34 urges-the-abutrnent 40 in a counterclockwise direction'asregards Fig.- l, movement ofthe-abutment- 49 bythe springhowever being opposed by the-thermoelee-tric ele-- ment Eil-which tends-to movetheabutment iny the: opposite direction under certain A conditions,

butunderiother conditions,- will permit movementA of the abutment by thespringdL-ina-counter-- clockwise direction as regards Figs. 1,` 2and-3.

The abutmentmemb'er 491 has two contiguous saw-

toothshapednotches

55 and 56 in its end edge oppositethe edge-or portion toiwhichtheV This" thermoelectric-v element is attached.

notch end edge of the abutment 4E) moves through the slotted contact carrying

exible blades

32 and 33 in a plane at right angles to the plane surface of said blades. The iiexble blade 32 has a resilient linger t!! provided thereon, this nger being shown integral with blade 32 and extending therefrom at a point in close proximity to the contact 3l thereon. The finger 6i! is of such a length that When its free end is seated in the saw tooth notch 5t of the abutment member li, said finger til is biased to exert a pushing force upon the Contact carrying flexible plate 32. Likewise plate 33 is provided with a resilient finger iii extending therefrom and secured thereto in the vicinity of the Contact 38 thereon, this finger El being likewise biased When its free end is seated in the saw tooth notch 55 'of the abutment lle, the linger being operative to exert a pushing force upon the flexible contact carrying blade 33. The knife edges of the saw tooth notches 55 and 5t are, as has been said before, contiguous, being spaced a predetermined distance one from the other. When the position of the abutment il@ is as illustrated in Fig. l, notches 55 and 5t are on the side of the respective

ilexible blades

33 and 32 so that the fingers 6l and 66 are biased to exert a pushing force upon the

blades

33 and 32 respectively to cause their respective contacts 33 and 3l electrically to engage the respective stationary contacts 22 and 2 i. Under these circumstances, the thermoelectric element 5s is comparatively cool and thus expanded and in its initially tensioned condition. However, if current is caused to flow through the thermoeiectric element 5t, which is in circuit connection with the contacts 3l and 38 through the abutment lli! and the respective engaging fingers E@ and @i of the blades then, upon a pre- Y determined current flow through the thermoelectric element 5t, said element will become heated, causing it to expand, its expansion permitting the spring Sii to become effective to move the abutment d@ counterclockwise as regards Fig. 1. In response to such counterclockwise movement of the abutment ll, thenger engaged end of the saw tooth notch 55 in said abutment will be moved toward alignment with the flexible contact carrying blade 32 and when said notch and its engaged linger @il reaches a predetermined position on the lower side of the blade 32 as shown in Fig. 2, the motivating force of the biased finger @il will be reversed thereby causing it quickly to thrust the blade 32 and its contact 3l toward the stop end 65 of the frame 23 which projects from the portion or side 25 thereof, whereby the circuit formerly passing between the contacts 3l and 2i will be broken. If expansion of the thermoelectric element 58 continues, due to continued or predetermined increase in current flow therethrough, spring 34 will continue to move the abutment lil counterclockwise as regards Fig. l, thereby moving the saw tooth notch 55 of the abutment and its engaging end of the finger 6l to the side of the contact carrying ilexible blade 33 in which the pushing force of the finger is reversed whereby blade 33 and its contact 3S will be moved away from stationary contact 22 to break the circuit. In moving in this direction, the rigid extension @t on the blade 33, normally not in engagement with flexible blade 32, will be moved to engage and rest against said blade 32 as shown in the Fig. 3. The Fig. 2 indicates the position of the switch mechanism in which the contact 3l has been moved out of engagement with its stationary contact 2i While 4 contact 38 is still in circuit completing engagement with its stationary contact 22.

From the aforegoing, it will be seen that in response to a predetermined current flow through the thermoelectric element its expansion is effected, thus permitting the blade spring 3ft to become active to actuate the abutment member i0 in a counterclockwise Vdirection as regards Figs. l, 2 and 3. During the predetermined range of such counterclockwise movement by the abutment liti, linger @El of the contact carrying flexible blade 32 is adjusted and brought into relative position with the blade 32 so that said linger will thrust the blade and its contact 3l into circuit breaking position as shown in Fig. 2. Continued expansion of the thermoelectric element 53 results in an adjustment of the abutment iii counterclockvrise to bring finger iii into a position relative to the main body portion of the flexible contact carrying blade 33 so that finger El will also thrust its contact carrying blade 33 to move contact 33 out of engagement with contact 22 and the extension t5 of blade 33 into engagement with flexible blade 32 as shown in Fig. 3.

Thus, it may be seen that contacts 3l and 3S are successively moved out of engagement with their respective stationary contacts 2l and 22 and their respective circuits broken in response to and in accordance with the expansion of the thermoelectric element 5S, due to predetermined current flows therethrough.

When the thermo-electric element 5S is permitted to cool due to a reduction or complete discontinuance of current flow therethrough, it will contract and consequently actuate the abutment it in opposition to the effort of spring 3e counterclockwise, thus moving said abutment il clockwise as regards the Figs. 1, 2 and 3. After the abutment d@ is moved clockwise from its position as shown in Fig. 3, the saw tooth notch E5 and its engaging resilient finger Sil will first be moved to the opposite side of the contact carrying flexible blade S2, thus tending to effect a movement of said blade 32 toward the stationary contact Zi. However, in this instance, blade 32 engaged by the rigid extension 6G on blade 33, will be retarded in its movement toward the stationary contact 2l due to the resisting force of the blade 33 which is still being urged into the open position as shown in Fig. 3 by its re- Silient linger Si. However, as the abutment 4B continues to move clockwise under the effect of the spring 3e, being gradually released by the thermo-electric element iid, the notch 55 and its engaging nger iii will be moved toward alignment with the contact carrying flexible blade 33. As the notch engaging end of finger iii approaches blade 33 from its position in Fig. 3, nger 6i will gradually exert a weakening force upon blade S3 to urge it into the position as shown in Fig. 3 and when the now opposing forces of iingers dei and t reach a balance at a predetermined position of the abutment ri, moving clockwise, both fingers and ti will concurrently and with a snap action thrust their respective contact carrying '

blades

32 and 33 toward the stationary contacts so that the contacts 3l and 38 on said blades respectivelywill electrically engage their respective stationary contacts 2i and 22 as shown in Fig. l. Thus it will be seen that the rigid extension @t on the contact carrying flexible blade 33 will, when properly adjusted, effect simultaneous engagement of the contacts 3i and S8 with their respective stationary contacts under the effect of the spring fingers E0 and 6l being slowly adjusted clockwise by the abutment member All, activated by the spring 34.

It will be seen that the present construction differs from the construction disclosed in the above identined Werner Patent No. 2,242,769 in that the contact carrying flexible blades in this instance are mounted upon the rigid frame and not upon the hinged or movable abutment irame as shown in the patent. The abutment in the present instance mounted upon a blade spring attached to the rigid frame is independently movable relatively to the contact carrying blade springs. These differences in construction provide a switch having the same characteristics as the patented switch but permitting the switch to be made more compact and smaller than would be possible to build the patened switch. The Figs. l, 2 and 3 illustrate the switch at slightly larger than double size while the Werner patent illustrates a switch of the same characteristics at full size. It may readily be seen that the switch of the present invention, due to its construction, would reduire considerable lesser material and therefore would be cheaper to produce and at the same time, by requiring less material, provides an important factor under conditions when material supplies for commercial use are being curtailed and restricted.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

l. An electric switch comprising in combination, a rigid frame; a movable abutment; exible means securing the abutment to the rigid frame, said flexible means constantly urging the abutment in one direction; thermo-electric means attached to both the rigid frame and the abutment and operative to actuate the abutment in the opposite direction in opposition to said ilexible means; stationary contacts; cooperating ilexible contacts secured to the rigid frame; and a flexible biasing element on each exible contact, said biasing elements respectively seating in contiguous notches in the abutment, each biasing element being operative to actuate its respective flexible contact in one direction or the other, dependent upon the position of the notch occupied by it, relatively to the respective flexible contact,

2. An electric switch comprising in combination, a rigid frame; a movable abutment; a blade spring anchored to the abutment; stationary contacts; cooperating flexible contacts; common means securing the blade spring and flexible contacts to the rigid frame, said blade spring constantly urging the abutment in one direction; thermo-electric means secured between the rigid frame and abutment and being operative to actuate said abutment in the opposite direction in opposition to the blade spring; contiguous notches in the abutment; and a ilexible biasing nger on each flexible contact, each finger being seated in a respective notch in the abutment, said fingers being operative to move their respective flexible contacts in one direction or the other in response to movement of their respectively engaged abutment notches to the side of the flexible contact opposite its resultant movement.

3. An electric switch comprising in combination, a rigid frame; a blade spring and two ilexible contacts anchored to the rigid frame; an

abutment securedfto and carriedby saidv blade v spring which constantly urges the abutmentiin one direction; stationary contacts each adapted to be engaged by a respective flexible contact;

a thermo-electric element insulatingly secured to the rigid frame and electrically anchored to the abutment, said element being operative to actuate the abutment in the opposite direction in'opposition to the blade spring; and a resilient finger on each flexible contact, one end'of each'" finger being secured to its respective ilexiblevcon tact, theother end of each-finger being seated*- upon the edge of the abutment and therebl` biased, one finger contiguous to the other and in`vv such positions relatively to their respectivefflexia ble contacts as to provide over-center-"mechaenism adjusted by the movementof the abutment;' to thrust said flexible contacts in one direction or the other` relatively to the-stationary conta-cts.

4; An electric switch comprisingin combina"-Y tion, a rigid frame having an angular extension;

two stationary contacts; two longitudinally slotted, resilient contact blades each engageable with a respective stationary contact and an chored at one end to the angular extension of the frame; a blade spring anchored with the resilient contact blades to the frame; an abut# ment secured to the blade spring which urges the abutment to move in one direction through" the slots of the resilient contact blades, transversely thereof, said abutment having two con-v tiguous notches in its outer end edge; a thermoelectric element electrically anchored to the abutment and insulatingly to the frame, said element being operative to operatethe abutment in opposition to the blade spring whereby the-notches in the actuator are moved across the transverse plane of the resilient blades in one direction or the other; and resilient fingers on each resilient contact blade, biased by seating the free ends thereof in a respective notch of the abutment, said lingers thrusting their respective contact blades in one direction or the other dependent upon to which side of the resilient contact the notches are moved by either the blade spring or thermo-electric element.

5. An electric switch comprising in combination a rigid frame; two stationary contacts; two flexible contacts each adapted to engage a stationary contact, each flexible contact being longitudinally apertured for a portion of its length; a resilient blade; common means anchoring one end of each llexible contact and the blade to the frame, the blade being sandwiched between the flexible contacts; an abutment anchored to the blade which constantly urges the abutment in one direction transversely of the two flexible contacts, said abutment having two contiguous notches in its one end edge; a thermo-electric element electrically secured to the other end of the abutment and insulatingly anchored to the frame, said element being operative to exert an actuating force upon the abutment in opposition to the blade spring whereby the abutment notches are shifted transversely of the respective flexible contacts from one side to the other thereof; a resilient finger on each exible contact, each finger being biased by seating the free end thereof in a notch of the abutment whereby actuation of the abutment bythe thermo-electric element or the blade spring causes said flexible contacts simultaneously to engage or successively to disengage their stationary contacts respectively.

G. A device in accordance with claim 5 in which, however, an adjustable extension is proaeiaoot vided on the one ilexible contact, said extension only engaging the other flexible contact when both contacts are disengaged from their respective stationary contacts, whereby concurrent engagement of the flexible and stationary contacts is facilitated in response to actuation of the abutment by the thermo-electric element.

7. An electric switch comprising in combination. a rigid frame; stationary contacts; cooperating flexible contacts one end of each being anchored to the frame; a blade spring secured to the frame; an abutment carried by the blade spring which constantly urges the abutment in one direction transversely of the flexible contacts, said abutment having contiguous notches in its free end edge movable from one side to the other of the transverse plane of a respective flexible contact; thermo-electric means insulatingly secured to the frame and electrically to the abutment, said means being operative to move the abutment in opposition to the blade spring; resilient fingers on each flexible contact, each linger being biased by seating one end in a respective abutment notch, each finger being operative to actuate its respective flexible contact in accordance with the position of the notch it occupies, relatively to its ilexible contact; and an adjustable rigid projection on one flexible contact, operative to engage the other flexible contact only when both flexible'contacts are disengaged from their respective stationary contacts.

8. An electric switch comprising a base, two insulated, stationary contacts carried by the base; a rigid frame secured to the base; two slotted, liexible blades, one end of each blade being anchored to the frame, the other end of each blade supporting a contact one of which cooperates with one stationary, the other with the other stationary contact for controlling electric circuits; a blade spring anchored to the frame in superposed relation to the flexible contacts; an abutment carried by the blade spring, said abutment having two contiguous notches in its outer end edge the abutment being movable transversely of the flexible blades through the slots thereof; a resilient finger secured to each cf said iiexible blades adjacent the respective contacts thereon each finger being biased by placing its free end into pivotal engagement with a respective notch in the abutment, the bias of each finger effecting operation of the contact carrying blades toward or away from their respective cooperative stationary contacts in accordance with the position of the notches in the abutment relatively to the respective contact carrying blades; and a thermo-electric element insulatingly connected to the rigid frame and electrically to the abutment, said element being operative in accordance with current now therethrough either to actuate said abutment against the effect of its supporting blade spring to cause contact disengagement or to permit said blade to move the abutment to effect contact engagement.

HARRY C. SWAN.

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

UNITED STATES PATENTS Number Name Date 2,242,769 Werner May 20, 1941 2,278,990 Hall Apr. 7, 1942