US1821180A - Electric switch - Google Patents

Description

A. C. GAYNOR Sept. 1, 1931.

ELECTRIC SWITCH Filed Aug. 8, 1928 2 Sheets-Sheet l IN VEN TOR. Ar/ Lr 6@ 0r A T RNEY "A. C. GAYNOR ELECTRIC SWITCH Sept l, 1931.

Filed Aug. a, 1928 z'sneets-sheet 2 INVENTOR. A///urC-'f 2.1/0

TORNEY Patented Sept. 1l, 1931 PATENT FFICE ARTHURl C.. GAYNOR, QF STRATFORD, CONNECTICUT ELECTRIC SWITCH Application. led August 8, 1928. Serial No. 298,218.

This invention relates to improvements in electric switches, and has particular reference n s 1 to switch arms and niouiitings therefor 11i quick acting or snap switches. 5 Heretofore, in snap or quick acting switches-such as, for instance, those used in house wiring-the switch was made a permanent,

and inseparable part of the actuating mechanism, so that it was practically impossible to change the switch over from one having a certain arrangement of the switch arm or arms from one having a different arrangement of the'latter. Hence, it was the custom to pro'- vide a number of different assemblies of the switch actuating mechanism and switch arms for these diilerent uses, so that in making up a switch, the assembly having the yarrangement of switch arms needed for the particular kind ofswitch wanted was selected and assembled in the supporting means.

Now, itis an object of this invention to provide means whereby the switch arm or arms may be applied to or removed from the switch actuating mechanism readily by hand and without the use of tools. Thus, in assembling a switch, if only one switch arm is wanted, only one is applied to the actuating mechanism, and a saving in material and labor is effected. Again, if in practice it is desired to change over a switch from one kind to another, this may be done readily by changing the arrangement of the switch arm or arms on the actuating mechanism or by adding another arm in case only one was originally provided and two are wanted.

Further, according to the present invention, it is convenient and easy to interchange one kind or" switch arm with another and diferent switch'arm. For insta-nce, the present inven- 40 tion provides two specifically diii'erent'kinds of switch arms, one kind being adapted to be electrically connected to the actuating mechanism, while the other is adapted to e insulated therefrom, and so arranges these that they are interchangeably mountable on the actuating mechanism.

A further advantageous feature oi' this prol vision by the present invention of `means whereby one switch arm may be readily removed and another applied is that it enables a switch arm, which has been worn-out, broken, burnt or otherwise made defective in ilse, to be replaced by a new and perfect switch arm, a result which cannot be obtained in switches heretofore provided, without necesv sitating the substitution ot' a new actuatm mechanism, or an entirely new switch.

In the exempliiication of this invention, herein described and illustrated, the switch arm comprises a pair of juxtaposed blades having aligned apertures of non-circular formation adapted to be freely slid onto a portion of the actuating mechanisms which is similarly formed, so that the switch arm may move bodily laterally on the actuating member, as when being applied to or rcmoved from the latter, but will oscillate with the actuating member from one position of rest to another. This lateral bodily movement ofthe switch arm is unrestricted by the actuating incmbei but is held within limits `by portions of the supliorting structure for the moving parts of the switch. As illustrated, it is limited on the one hand by a supporting frame for the actuating mechanism and on the other hand by a cover meniber for the switch.

According to the resent invention, thc switch arm is not on y mounted for bodily lateral movement but also may swing later- 8c ally a limited extent on the actuating member; and the juxtaposed blades, when such I constitute the switch arm, have lateral swaying movement on the actuating member independently of each other, so that they may 35 shift to properly engage the stationary con-v tacts to compensate for unequalities of manufacture and so that the blades being yieldingly urged toward the stationary contact may1 have firm rubbing engagement tliere- 9o wit This latter feature enables the blades to be made of stiff or non-flexing material, and

`thus the blades may be given a greater crosssectional area `without undue `width, and e5 may be composed of material having greater electrical conductivity than has been. possible with previously ,proposed constructions wherein the blades themselves were mmhx rcsilient for the purposes above referia-l to.

F or yieldingly urging the blades toward themselves.

With the non-flexible blades of thepresent invention, the danger of the heat resulting from arcing, annealing the spring which yieldingly holds the blades together is reduced to a minimum, for the spring is located adjacent the mounting of the blades and remote from the contact engaging ends thereof. In the switch blades heretofore proposed, the heat L,from arcing frequently became so excessive as to anneal the springy blade and make it non-resilient, so that it would fail to properly engage the stationary contact. w l

The present invention further guards aga-inst loss of proper contact between the blades and the stationary contacts by so arranging the spring which holds the blades together in operative position that., should it become heated, the pressure produced against the blades will increase rather than decrease, as it would do were the spring so formed'that it would expand upon being heated. t

Other features and advantages will hereinafter appear.

In the accompanying drawings, which are exemplary of the present invention,

Figure 1 is a top plan view of a switch with the cap or casing removed, soas to show the switch arms and their supporting means and coperating stationary contacts.

FiO. 2 is a longitudinal section taken on,

the lines 2 2- of tFig. 1, the cap bridge and face plate being shown in normal position on the switch.

Fig. 3 is a transverse section taken on the line 3-3 of Fig. 2.,.

Fig. 4 is a disassembled perspective view of parts of the swi ch arm shown `on the left-hand side of Fig. 3.

Fig. 5 is a disassembled perspective-view of the switch-arm shown on the righthand side of Fig. 3, and the switch arm actuating mechanism.

Fig. 6 is a diagrammatic view of the switch arm shown in Fig. 5, showing the position to which the blades may move in dotted lines greatly exaggerated for illus trative purposes.

Fig. 7 is a'modified form of spring device for holding thc blades of a switch arm to gether.

Fig. 8 is an end View of a spring clip made in accordance with this invention. i

The switch shown in the accompanying drawings for the purpose of illustrating the present invention comprises a base 10 having a cap or cover l1 (see Figs. 2 and 3) through which pass a pair of screws 12 threaded in a metal strap or bridge 13 by means of which the base and easing are held together in superposed relation. As shown, a flush plate 14 is secured to the bridge 13 by screws 15. The casing 11, metal strap 13 and iush plate 14 are provided with aligned openings through which a hande or finger-piece 16 extends for manual or other operation.

Supported by the base 10 and mounted within the base and casing 11 are stationary contacts 17, 18, 19 and 20, each of which has in electrical engagement therewith a binding screw 21 for connection to wires of one or more electric circuits adapted to be controlled by the switch.

In most cases and as shown, the contacts 17, 18, 19 and 20 are electrically insulated from each other. In a double pole double break switch, such as is shown, the contacts 18 and 20 are located at one side of the base lOand adjacent the bottom thereof while the contacts 17 and 19 are located at the other side of the base and extend upwardly a substantial distance from the bottom of the hase, so as to be diammeti'ically opposite the contacts 18 and 20 respectively. The gaps between the two pairs of contacts 17-18 and 19-20 respectively, may be bridged or closed by switch arms 22 and 23 respectively, in one position of rest of the switch andopened in the other position of rest.

The positions of'rest of the switch arms, that is the on and off positions of the switch, vare controlled by the finger-piece orf handle 16, which is made in accordance with my invention described andclaimed in niy copending application, Serial No. 276,886, f led May 11, 1928. In the switch shown, the handle 16 is provided with a rocker arni 211,

the portion 25 of which extends into a slot in the handle and is provided with abearing opening aligning with bearing openings in the handle to receive a bearing pin 26 which 'is also adapted to pass through and be supported by side arms 27 of a frame 28 carried by the base 10. The lower end of the rocker arm 24 engages a compression spring 29 which is carried by a U-shaped crank 30. i The U-shaped crank 80 has flat laterally extend,` ing arms 31 adapted to engage supporting fulcrums 32 provided on the frame 28. vIn the form shown, the fulcrums 32 are of i-nverted tl-shape, but so far as the invention described and claimed hereinjiS` concernei'hl they may be of any forni desired. TheaI-, rangement of the rocker arm 24 and the 4crank4 3() is such that in position of rest the end of' the arm 211 is at one side of the axis of oscillation of the crank while the lower end of the crank 36 is at the other side of said axis. Consequently, when the protruding side of the finger-piece 16 is depressed, the arm 24 is rocked and the spring 29 is compressed storing sufficient energy so that after the arm 24 passes through the `axis of oscillation of the crank 30, the crank will be snapped quichly by the spring 29 vto the opposite side 3 1-, preferably rectangular in cross section,

onto which the switch arms having rectangular apertures 22a and 23a respectively, may be slid. Thesizes and shapes of the extensions 32 of the apertures 22a and 23a respectively, are such that the switch arms may be slid by hand onto the extensions 32 with `such freedom that the switch arms may have lateral movement unrestricted by the extensions. Moreover, the extensions 32 are substantially identical in size and shape, as are the apertures 22a and 23a, so that either switch arms 22 or 23 may be mounted on either extension, as desired.

Further, in 'accordance with the present invention, each switch arm is formed of a pair .of separate blades. These are designated 33 and 34 in the switch arms 22 and 23 respectively, the blades of each pair being shown separated in Figs. 5 and 4 respectively. These blades being structurally separate are capable of having lateral movement on the extensions each independently of its companion. For this purpose, in the blades 33 of the switch arm 22, which is ofthe kind usedwhen it is not necessary to insulate t-he switch arm from the actuating mechanism, theapertures 22a are formed directly in the blade.

In the switch arm 23, however, which is of the kind adapted to be insulated from the crank, each blade 34 is provided with a member 35 of insulating material in which the aperture" 23a is formed. Each insulating member 35 is provided with a flange 36 and a boss 37, the formerl being adapted to engage the outside face of a blade while the boss 37 extends through an aperture 38 in that blade and terminates in the plane of the inner face of the blade. 37 are made non-circular so that the insulating member 35 and the blade 34 together will oscillate with the crank when the blade is mounted thereon. The insulating member and its blade may be held together by any suitable means, it' being suflicient if the boss -37 merelyl slidingly fits the aperture 38 in the blade, -for other means provided by the lpresent invention and described below will effectively hold the parts together in proper relation.

For convenience in handling the parts when assembling or re-arranging the switch, however, it is preferable that the boss 37 on the insulating member 35 and the aperture 38 in the blade have a press-fit, i. e. a snug tit The aperture 38 and the boss caused by forcibly pressing the boss into the aperture, so that the blade 34 and insulating member 35 become after that a structural entity.

Notwithstanding the interpositioning of the insulating member 35 between the blade 34 and the crank extension 32, the blades 34 may freely slide on the extension and may have the same other movements, characteristics and advantages as the blades 33, the metal portions of which slide directly on the crank extension 32.

Irnthe disclosed embodiment of this invention, the pairs of blades 33 and34 straddle their associated stationary contacts when they engage the latter. Hence, each blade is provided with an off-setting bend 39 between its central or mounting portion 40 and its contact ends 41. The extent of this off-set is sufficient to allow the adjacent contact ends 41 of each pair of blades to be spaced apart somewhat (slightly less than the thickness of the stationary contacts), whilethe central portions 4() are in contact with each other face to face, as shown in Fig. 3. This spacing of the contact ends 41 facilitates the entrance of the vstationary contacts between them and this the adjacent blades to spread and straddle the stationary contacts, and resiliently hold the contact en`ds 41 'in firm' engagement with the stationary contacts. This means, in the embodiment of the invention illustrated, consists of a spring clip 43, one being provided for each switch arm and each being substantially U-shaped and having legs 44 adapted `to be slid over the central portions 40 of the juxtaposed blades constituting a switch arm to straddle the same.

In the broader aspects of this invention, the spring clips 43 may be held in place by any suitable means. For instance as shown in Fig. 7, the spring clip 43a may be permanently secured, as by rivets 45, to either of the blades of a pair. However, to facilitate they manufacture and asembly of the device, to permit linterchange of one blade for another without the use of tools, and foi` other reasons, it is preferable that the spring clip 43 be structurally.y separate from the blades, as shown in Figs.A l to 5; and, to keep it in operative position relative to the blades, the legs 44 of the U-shaped spring clip 43 are provided with apertures 46 conforming to the extensions 32 of the crank.

lIhus, when assembling the switch. the

pair of blades 33 or 34 (the latter with their by hand face to face with the central portions 40 in contact and with` the apertures 22a and 23a, as the case lmay be, substantially aligned. Then the legs 44 of the U- 5 shaped spring clip are spread and slid over the outside faces of the central portions 40 until the apertures 46 in the legs substantially align with the apertures in the blades, the tension of the sprin clip 43 being suicient to hold the parts rictionally together as a sub-assembly at this time. And, finally, the assembly is slid onto the extension 32 of the crank, the latter passing successively through the aperture 46 in the inner leg 44 of the spring clip 43, then through the aperture 22a or 23a-in the inner blade, then through the aperture 22a or 23a in the outer blade, and finally through the aperture 46'in the outer leg 44 of the spring clip. When thus mounted, the parts are held in alignment by the extension 32 of, the crank and the spring clip presses them together with the proper amount of tension. Yet, the switch arm assembly may move laterally on the crank and the individual 'blades may move laterally independentl of each other both bodily and pivotally, or the apertures 22a and 23a are made long enough to permit of slight skewing movement of the blades. Hence, the blades will locate and properly straddle the stationary contacts, even though there may be present slight variations and inaccuracies resulting in the manufacture of the parts. To centralize or equalize the blades, the legs 44 of the U-shaped spring clip 43 are made substantially wide andlie substantially flatagainst the central portions 40 ofthe blades which themselves are flat. Thus, the legs 44 of the spring clip tend to hold all the parts fiat against each other as shown in Fig. 6, and should a skewing or lateral swinging movement of one or more of the blades occur when straddling a contact, the legs of the spring clip will return the parts to their normal positions as soon as the switch is moved to off position.

The legs 44 of the spring clip for the blades 34 of the spring arm 23 are insulated from the blades by the flanges 36 of the insulating member 35 with which the legs directly engage, and the base 47of the spring clip 43 is remote from the blades so as to be spaced therefrom by an air gap. Thus the blades 34 of the switch arm 23 are electrically insulated from the crank, and yet, like the blades 33 of the switch arm 22, are held together 4 by a spring clip.

Even if the insulating members 35 should.

or material of the blades but on the springclip 43. Therefore, the blades may be made, according to this invention, of the most suitable materials (preferably an alloy of high copper content) and 4may have the desired cross-section, reducing the internal resistance of the switch to a minimum. Moreover, v

since the material of the blades may be of high copper content, or pure copper for that matter, danger vof the blades becoming frozen to the stationary contacts by oxidizationduring periods of disuse is mitigated.

In practice, it has been found that-the arcs resulting from breaking of contact between the contact ends 41 of the blades and the stationary contacts develop an intense heat which is, of course, conducted along the switch blade. vWhen the switch is operated vunder heavy load in rapid succession, it has been found that the heat developed tends to expand the resilient means provided for holding the contact ends `against the stationary contacts, with the result that poor contact is had, more arcing occurs', and more heat is developed.` To overcome this dit'riculty, which is not so aggravated with a switch made in accordance with this invention as with those heretofore proposed, VVthe spring clip 43 of the present invention is so shaped that upon being heated the normal space between the legs 44 decreases so that the pressure of the spring clip upon the blades increases when the switch heats up and causes the blades to make tirm'er engagement with the stationary contacts. To do this, the spring clip is provided between its base 47 and the legs 44v with reverse bends 48 and 49, as shown in Fig. 8, on an enlarged scale. Thus, upon being heated, the portion of the clips adjacent the bends 48 and 49 will tend to straighten out and assume the positions shown in dotted lines in Fig. 8, with the result that the legs tend to lie closer together and thus increase the pressure between them.

In order to keep the switch arm on the eX- tcnsions 32 so that it will not slide thereoli' when the switch is in use, the extension 32 is continued outward so that its end lies so close to the portion 50 of the side wall of the casing l1 that no part of the device can slip between its end and the portion 50 of the wall. Operating lateral movement of the switch arni on the extension 32 of the crank held within the limits by the wall 51 on the casing 11 and by walls 52 and 53 on the base l0. These walls 51, 52 and 53 form channels, one being provid'ed at each side of the switch, in which the switch blades move,

the laterally bent ivings being adapted to engage these walls should the switch arm move laterally too far either one way oranother. It should be noted that the upper portion of'the wall 53 cooperates with the wall to be mounted upon-and removed from the extension 32 of the crank, and for other purposes, the frame 28 carrying the actuating mechanism is removablymounted on the base. -In fact, it is just slidably mounted in' a socket arranged to lit it, but this feature also of the present invention is not claimed herein and forms vthe subjects-matter of another application. Suffice it to say that the actuating assembly shown in Fig. 5 is held in the hand while the switch arm sub-assembly comprising the switch blades 33 and spring clip 34 is either slid upon or removed from the extension 32 after the frame 28 is replaced in the. base .and lateral movement of the switch arm is againheld within limits by the base and casing. In this way, the switch arms 22 and 23 may be changed around as kdesired by merey hand operations after the casing 11 is removed, and any arrangement desired for a particular kind of switch may be effected.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used with- Aout others.

HavingI thus described the inventiomwhat is claimed as new and for which itis desired to obtain Letters-Patent, is

1. In an electric switch, a rocker; a crank;

a spring interposed between the rocker and crank and adapted to cause the latter to oscil- 'late with a snap action from one position of rest to another when the spring is carried by the rocker across the axis of oscillation of the crank; and a non-iexing, substantially rigid switch arm mounted on said crank for oscillation therewith and freely mounted on the crank for limited lateral swaying movement thereon.

2.` In an electric switch, a rocker; a crank: a spring interposed between the rocker and crank and adapted to' cause the lattter to 4oscillate with a snap action from oneA position of rest -to another when the spring 1s comprising a pair of non-flexing, substantially rigid blades mounted in juxtaposed positions on said crank for oscillation therewith and slidably mounted on the crankv for bodily lateral movement thereon independently of each other.

3.- In an electric switch, a rocker; a crank; a spring interposed between the rocker and crank and adapted to cause the latter to oscillate with a snap action from one position of rest to another when the spring is carried by the 'rocker across the axis of oscillation of the crank; and a switch arm comprising a pair of non-flexing, substantially rigid and separate blades mounted on said crank for oscillation therewith and freely mounted on the crank for limited and independent lateral swaying movement on the crank.

4. In an electric switch, a base; a rocker; a crank; a spring interposed between the rocker and crank and adapted to cause the latter to oscillate with a. snap action from one position of rest to another when the spring is carried by the rocker across the axis of oscillation of the crank; a switch arm slidably mounted on the crank adapted to oscillate with the crank and at all times free from interference with the crank to slide on and off the crank; and a removable closure device for the switch adapted to engage the base and having means which in operative osition prevents removal of the switch arm rom the crank. v Y

5. In an electric switch, a rocker; a crank; a spring interposed between the rocker and crank and adapted to cause the latterv to oscillate with a snap action from onev position of rest to another when the spring is carried by the rocker across the axis of oscillation of the crank; a frame within which the crank is vmounted for oscillatory movements, said lwhen the first-named switch arm'is carried by the iirst-named extension; and a support in which the frame is removably mounted, said support having means loc'ated in close I proximity to the end of each extension to pre-c,

vent the switch armswhen carried thereby from sliding laterally. Said extensions when said frameis in operative position on said support. l

6. A switch arm comprising a pair of struc- 4blades together, said clip having apertures aligning with the blade apertures so as to receive the operating shaft and to be held in operative engagement with the `blades by the operating shaft.

8. A switch arm comprising a pair of juxtaposed blades having aligning non-.circular apertures adapted to receive a non-circular portion of an operating shaft so as to rotate with the sha'ft; and a spring clipstraddling the juxtaposed blades to yieldinglyhold the blades together, said spring clip having apertures conforming to the non-circular portion yof the shaft and adapted to receivethe shaft and be held in operative engagement with the blades by the operating shaft.

9. A switch arm comprising a pair of structurally separate juxtaposed blades having aligned apertures adapted to receive an operating shaft, portions of the blades containing said apertures being off-set inwardly so that such portions mayengage while end portions of the blades are spaced to receive between them stationary contacts; and a spring clip for yieldingly holding` in contact portions of the blades containing the apertures and also yeildingly holding the blades together so that the contact engaging portions of the blades are equi-spaced at opposite ends of the switcharm. .y

10. A switch. arms comprising a pair of structurally separate juxtaposed. blades having aligned apertures adapted to receive an operating shaft, portions of the blades containing said apertures being oE-set inwardly so that such portions may engage while the other'portions of the blades are spaced to receive between there stationary contacts, the

inwardly o1i-set portions being adapted to act as fulcrums for one another when it is necessaryl for the blades to spread a greater -distance at one end of the switch arm than at the other; and spring means tending to hold the inwardy off-set portions flat against each other to equalize the distance between the blades at their opposite ends.

11. A switch arm comprising a pair of structurally separate juxtaposed blades having aligned apertures through which an operating shaft may extend; an insulating plate for each blade having a boss adapted to fit within the aperture in the blade,

said bosses having aligned apertures adapted to receive the operating shaft, the bosses on the insulating plates terminating in the plane of the adjacent faces of the blades so that the blades may contact with each other; and a spring clip adapted to hold together the blades with their insulating plates.l I U 12. A switch arm comprislng a pair of structurally separate juxtaposed blades having aligning apertures through which an opbosses on the insulating plates terminatingin the plane ofthe adjacent faces of the blades so that the blades contact with each other; and a spring clip adapted to yielding. ly hold together the blades with their insulating plates, said spring clip straddling juxtaosed blades and having apertures conforming to the non-circular portion of the shaft so that the spring clip is held in operative position relative to the blades and their insulating plates by the shaft, the insulatingl plates being interposed between the blades and the spring clip so as to electrically insulate the blades from the spring clip and the shaft, and the straddling port-ion of the spring clip being so far remotefrom the plates as to be out of electrical contact with the blades.

13. A switch arm comprising a pair of identical, structurally separate blades having ofi-set bearing portions which when the blades are brought together causes the contact-engaging portions on adjacent blades to be spaced from each other, the bearin portion of each bladel being provided with an insulating plate fitting within the off-set portion and having a boss fitting within an aperture in the blade, the boss on each plate terminating in the plane of the opposite face of 'the blad-e; and means for holding the blades together for operation.

14.151 switch arm comprising a pair of structurally separate juxtaposed blades, each` blade being provided with a molded insulating plate having a boss extending into an aperture 'in the blade, said bosses being provided with aligned apertures adapted to receive a portion of a crank shaft.

15. A switch arm comprising a pair of structurally separate juxtaposed blades; and

resilient means for holding the vblades in' juxtaposed positions, said means being so shaped that expansion thereof resulting from heating causes the tension of said means on the blade to increase.

16. In an 'electric switch; a rocker; a crank; a spring interposed between the rocker and crank and adapted to cause the latterv to oscillate with a snap action from one posi: tion of rest to another when the spring is carried across the axis of oscillation of the crank; a pair of switch arms; and means on the crank for removably and interchangeably supportinmsaid switch arms for oscillation therewith.

17. A snap switch comprising a support, a pair of contacts, an actuating mechanism including an oscillatory element, an insulator having floating connection With said element, a Contact blade mounted upon said insulator, and means for restraining the lateral movement of said blade.

Signed at Bridgeport, in the county of Fairfield, and State of Connecticut, this 7th day of August, 1928.

ARTHUR C. GAYNOR.

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