US2807685A

US2807685A - Switch

Info

Publication number: US2807685A
Application number: US349737A
Authority: US
Inventors: Max L Jeffrey
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-04-20
Filing date: 1953-04-20
Publication date: 1957-09-24
Anticipated expiration: 1974-09-24

Description

M. L. JEFFREY SWITCH Sept. 24, 1957 2,807,685

2 Sheets-Sheet 1 Filed A ril 20, 1953 IN VEN TOR. MAX L. Jff/Ef Y HIS 1777'02/VEY Sept. 24, 1957 M. JEFFREY SWITCH INVENTOR. 444x L. JEF/PEY H/SA7TOENEY 22v Sheets-Sheet 2 i-ig ml i Filed April 20, 19. 3

United States Patent SWITCH Max L. Jeffrey, Chagrin Falls, (Ehio Application April 20, 1953, Serial No. 349,737

11 Claims. (Cl. 200-70) This invention relates to improvements in quick acting switches, and more particularly to a switch of the type where the movement of an external lever connected to a shaft causes the build up and storage of energy by spring means which is applied to a rocker that is held against movement until the energy stored reaches a predetermined amount and the operating lever releases the rocker and the spring causes the rocker to snap to another position. The rocker carries sets of movable contacts which are brought into contact with fixed contacts in its alternate positions.

The present invention also constitutes a switch which has a plurality of fixed contacts that enables a greater versatility of connections into various circuits.

A further advantage resides in the ability to quickly change the switch by movement of the parts to provide a switch that is normally closed or normally open regardless of the movement of the operating lever; one where the making and breaking contacts are in a chamber where the arcingv is confined, increasing its efiectiveness against fire hazards and one where the circuit connecting screws are disposed for easy access for making connections and cannot interfere with the operating mechanism.

Still other advantages of the invention including economy of construction will become more apparent from the following description of an embodiment thereof, which description is illustrated by the accompanying drawings and forms a part of this specification.

'In the drawings:

Fig. 1 is an elevational view of one side of the switch of my invention with the cover plate removed;

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is a view similar to Fig. 1 from the side thereof;

Fig. 4 is a fragmentary section taken on the line 44 of Fig. 2;

Fig. 5 is an exploded view of the snap action assembly removed from the housing;

Fig. 6 is a fragmentary view of the lower half of the switches showing a modified form of construction;

Fig. 7 is a fragmentary medial section of Fig. 6;

Fig. 8 is a view similar to Fig. 6 with certain parts removed to more clearly illustrate the structure of the other parts;

Figs. 9 and 10 are alternate views showing different arrangement of contacts; and

Fig. 11 is a face view of a modified form of back bearing and return spring plate with the return spring in position; and

Fig. 12 is a side view with the spring removed.

Referring now to the drawings, throughout which like parts are designated by like reference characters, there is illustrated a housing which includes the side walls 10 but wherein the front and back are mostly open to enable easy assembly of the parts, the front and back being closed, after assembly of the parts therein, by cover plates illusopposite ,screws that are threaded into the screw holes 11. The

upper end of the housing is provided with a hollow interiorly threaded boss 12 for the reception of an electric wire conduit. The opening through the boss opens to the interior at the end adjacent to the terminals where the conductors may be connected.

Generally speaking, the switch includes a terminal support for the stationary contacts, a swingable, movable contact carrying member for cooperation with the stationary contacts and a snap action mechanism for swinging the movable contact member quickly between alternate positions.

The fixed contacts are so supported that their conductor attaching ends are convenient to the wire entrance to the housing. The structure of the housing is also such that easy access is had to the wire attaching screws. The support for the contacts is such that certain of the contacts may be omitted if desired, thus extending the versatility of the device. To these ends, a block 15 of insulating material, such as Bakelite is provided, being of general arcuate formation, as best seen in Figs. 2 and 3, and bridging the side walls 10. This block is held in position by a large insulating plate 16 located on the rear of the housing and a bar or bridge 14, Fig. 1, located at the front of the housing, the bridge preferably being integral with the housing. Interposed between the bridge and the block is a plate of suitable insulating material. The rear plate seats on ledges 18 formed along the sides of the housing at the rear. The front plate 17 is sandwiched between the block and the front bridging member 14 and the assembly is held together by long screws (not shown) which extend through the rear plate, block and front plate, and are then threaded in holes 21 in the front bridging member 14. The heads of the screws are countersunk in the rear plate. A sheet of insulating material 20 is dis- Iposed between the plate 17 and the bridge 14 and extends toward the front of the housing to provide additional insulating protection between the contact screws and the front bridging member, since the bottom ones of'these screws are relatively close to the bridging member.

The front and rear faces of the block 15 are provided with vertically extending slots 23 into which the fixed contrated by the dot dashed lines which areheld in place by I tact carrying strips or bars are inserted prior to assembly, these bars being held in place by the clamping section of the rear holding plate against the bridge. A sheet of insulating material 20 between the bridge and the part 17 prevents shorting of front contacts.

The fixed contact bars are held against vertical movement since they are provided with notches 25 which allow the contact strips to protrude over the top and bottom of the stationary contact carrying block 15.

The block 15, together with its supporting plates and bridging member 14 provides a generally horizontal partition, dividing the housing into two

chambers

26 and 27. The upper chamber 26 has the connector ends of the fixed contact bars and the lower chamber 27, has the contact carrying ends. This is an additional precaution against the hazards of fire due to arcing during the break of the contacts since the two chambers are thus isolated from each other.

The ends of the contact strips are all bent to provide seats 28 which are threaded for the reception of the conductor holding screws 29, which thus all face in the same direction toward the front of the housing for easy installation of the wires.

The lower ends 31 of the contact strips, considering the outermost ones, are bent inward at an angle of approximately 45 degrees and carrying suitable contacting surfaces 32 of silver, tungsten or other suitable metal as may be desired. There is also provided a fixed central contact 33 formed in the shape of a V, each side of which 3 has contacts and. which face generally toward the outer contacts. It -will thus be seen that there is provided two center contact strips, one at the front and one at the rear, and that these are flanked by two pairs of outer contacts at the sides, thus providing three pairsof con contacts and Tthe center contactsa Thesevbars are carried by a rocker or swingable member 45 of insulatingma terial .whichmay be. SWLmg' iO-HIiETHBiE POSiKlOHS warm the foregoing.

As canbestbe-seenzin Figs. 1, the lower partiof the housing-has formed integral therewithi a: cross-beam 40;. the center of which is provided with laboss 4l which hasa horizontally. extending. bore 4Z, .Eig.. 2,.thatireceives a: pin 43. The pinv pivotally supportsithe. contact carri'er orsrocker45.since it extends through a bore in thetro'ckerz Athead 44 on. the. pin engages the-irockeriandlholds it againstithe. boss 41 while theother end'extends th rough the boss and isfsecuredbye suitableilock 46;. Inztheiem bodiment shown, the. pinis. upset slightlybeyondtihe: washer to: hold the same in place.

6 washer'in a groove on the pin. Inany eventgit should be understood that the rocker is freeto rock onthe pin 43. It. will also be appreciated that, althoughthecross beam 40 is shoWnasbeingintegral withthe housing it could very wellbe a separate part if desired;

The rockeritself.includes an upper head portion 50. disposed .abovethe beamAO W-hich supports the contact bars: and a. lower. operating stem 51 disposed belowth'eibeam and in engagement with and-"forming a part. of the-snap action. mechanism which cooperates with" it to'perform the swingingmotion' previously mentioned.

As can best be seenin Fig: 2, the rocker, in longitudi nal-crosslsection, includes a" thin upper part extending above a somewhat thickcrmid se'ction, the lower portion having a more complex-formationwhich will bemore fully described later.

The upper portion 50 -as stated is thin enough so-that it may move freely in. the space between the-'fixed'front' and back contacts. This head portion is.also-of general' T shape with the top-surface curved to conform to the arch of the fixed contactcarricr 15 (Fig. 3.), since' it swingsfrom oneside of:the' housing to' the otherbelow that arch- It isalsor provided: withitwoopenings-SZ extending transversely through the head from thefront to the rear. These openingsSZare of generally rectangular: formation, except thatthe end walls may be.curvedi' to conform to the curved: shape. of the movablei contact bars 55.

As can,;best be'seen in Fig- 2, the-movable: contact bars: 55-are generally, H shaped, and may be made-of metal having a concave-convex cross section. Theyare inserted in pairs in the openings 52 withtheconvex side-facing, one toward the side contacts'and the other toward the." center contacts, and are held by springs 56, seated resiliently. against the curvedend walls. Eachof the springs is seated on lugs on.theconcave side oris; inthis case, the. ends of the spring mayabebentoutwardi and engage; in holes in the bars: When lugs. areusediforrmounting.

the springs, the springs may be oppositethe: enlarged ends. As shown in the drawings,.however, one. spring for eachaset of contacts. will sufiice. Preferably, the. ends are made of a suitable. contact metal, but they may' also have contacts carried thereby if desired; It will be noted that the contacts:- being convex when, moved into.

engagement with the fixed contacts provide a rocking;

It will- :be apparent; however, that the. preferred. construction contemplates-a 4. action which assists in making a good contact of a line variety whichalso insures longer life. The contacts are sufiiciently long that they each are able to bridge the gap between each of the front and rear fixed contacts of the pairs of contacts.

It is preferred that the angle of inclination of the fixed contacts be such that when the movable contacts engage them they are drawn across the fixed contacts with a wiping action. This is best effected by fixing the plane of the fixed contacts-so that it passes to one side of rather than through the center? of rotation of the rocker.

The swinging of therocker is accomplished by a mech anism which cooperates with the lowerend of the rocker and which includes means whereby energy is stored up and, upon the movement of a lever, is suddenly released to cause the rocker to be snapped from one position to another. Provision is made for a certain amount of over-travel of the operating lever in'order toprevent damage to the mechanism and also increase the versatility' of'its use.

In. order toxenable the foregoing to be effected, a shaft 60'is provided. The shaft is formed witha-serrated stem 61' which is split and has an expansion screw 62 threaded in the split end to enablea' lever which may take many different forms, depending'on its use, to be securely heldon the end ofthe shaft." Adjacent the stem 61 there is provided a bearing surface 63 which is rotatably. journalled in a bearing 64 of the boss 65 on the lower end of the housing.

The end of the shaft 60remote' from the stem 61 is provided with a short bearing surface 67 which is journallediin a bearing plate 68. The plate 68 is supported on ledges 69 formed on the sides of the housing, the plate being providedwith wing shaped" arms 70 which seat'on' these ledges and the pointed ends 71 of which abut. the-screw receiving bosses 72 and the lower surfaces 73 ofwhich rest on-the shoulders 74 formed on the housing. It will thus be seen that the plate is held against'lateral movement in the housing and is held in place in the housingby the'back plate 9.

The shaft60, Fig. 5, is provided with two key ways diametrically opposite each other that enable it to drive a cam element 83 and a spring operating element 86'. In order thata better understanding may be had, it is pointed out that the shaft drives the spring operating ,element 86 which inurn moves the spring 90' which engages and tends to move the rocker. The rocker cannot move, however, because it is held by one of the dogs Energy is therefore storedup in the spring until such time asthe cam 83 releases the dog fromengagement with the rocker at which time the spring moves the rocker The mechanism for effecting this motion is shown in Fig. 5, the parts being arranged in the order of their assembly. As can be seen in Fig. 2, the cam element 83 is disposed next to the key 82' which is engaged in a groove 82' in the shaft to hold the shaft'in the housing. The C washer 82'bears against the inner. surface of the boss 65. The cam element 83' has lugs 84 which engage in the grooves or keyways 80 extending longitudinally of the shaft. The cam element is thus disposed opposite tothe longer end of the rocker and in alignment with the dogs or pawls 95 which are supported on pins 96'having reduced ends 96' and extend into bosses 100in the housing (Figs. 4 and 5), on opposite sides thereof. The dogs 95 are generally bell crank shaped having arms 95 that are arranged to engage the flat side or pawl seat surfaces101 on the. end of the rocker stem 51'. The other arm 97 of the doghas a cam engaging projection 93. which engages. with the/extremity of. the-dwell 99 'on the cam element! 83. The dogvis held with:the projection 98 pressed. against thecam element 83 andwiththe arm 95' oppositetheface 1010f the rocker'by-a spring l03'which is disposed on theprojection 104 onthedog and the other end of which engages the housing wall, as can best be seen in Fig. 4. There are two of these dogs disposed on opposite sides of the housing, and, if the cam element 83 is rotated clockwise, the edge of the dwell 99 (Fig. 4) rotates the right hand dog counter clockwise and gradually removes the end 95 from engagement with the face 101 on the rocker arm.

In the meantime, spring pressure is being applied to the rocker arm tending to rotate it toward the right (Fig. 4). The means for applying the spring pressure includes the spring operating element 86 which has lugs 86 also engaged in the keyways 80. This element 86 is provided with a pair of oppositely extending arms on its upper end, one acting as a rotor spring lever 105, and the other acting as a rotor return lever 105'. As can best be seen in Fig. 5, this element may and preferably is made in two parts which are placed back-to-back as shown. They can be welded together if desired but this is not essential. It is held in spaced relation from the cam element 83 by a washer 106 and spacer 107. Disposed about the spacer 107 is the spring 90 which includes the circular body and two upwardly extending spaced arms 109. The arms 109 extend upward toward the pivot of the rocker and engage a downwardly extending boss or projection 110 on the rocker on opposite sides thereof. This boss preferably has curved sides for tangential engagement with the inner surface of the spring arms 109. The arm 105 on the spring operating element 86 extends between the arms 109 of the spring 90 below the boss 110. Preferably, the spring 90 is formed so that the arms, in the unassembled state are relatively close together, and when assembled they engage the boss 110 with some pressure.

It can be seen that where the shaft is rotated counter clockwise as viewed in Fig. 3, the arm 105, being between the arms 109 of the spring, forces one of the arms away from the boss 110 which increases the pressure of the other arm against the boss and tends to rotate the rocker. This rotation is prevented, however, because the dog on the left has its arm 95' engaging the face 101 on the end of the rocker.

At the same time, the cam element is being rotated by the shaft and the dwell 99 of that element is engaging the projection 98 and the arm 95 is gradually being drawn downward from contact with the face 101. Eventually, the rotation of the cam is such that the dog rides on top of the dwell 99 and at this time the projection 95 is withdrawn from the abutting relation to the face 101. The maximum tension of the spring is thus present at the time the rocker is released. This movement may be considered gradual, although it may take place in a relatively short time depending upon the rapidity of movement of the shaft 60. The arms 109 of the spring are forced further apart and when the dog releases the rocker they come back together snapping the rocker quickly to the left (Fig. 3). This, of course, breaks the left hand and center right contacts and makes the center left and right hand contacts.

At the same time, the other dog (the one on the left as viewed in Fig. 3) is now moved counter clockwise by the spring 103 and its projecting arm 95 is brought up on opposition to the face 101 on the left side of the rocker arm.

As can best be seen in Fig. 4, the flat on the side of the rocker stem engages a fiat 100 on the boss 100 which thus enables the housing wall to take up the shock at the end of the swinging movement. It will also be noted that the thinness of the head of the rocker reduces the weight which, in turn, reduces its tendency to bounce.

A return spring 130 which is disposed about a spacer 131 journalled in the shaft 60 abutting the spring operating element 86 and which cooperates with the back shaft bearing plate 68 and the spring operating member 86 to urge the member 86 in one direction or the other depending upon the manner in which the return spring is.

assembled in relation to the back plate 68 and the member 86.

The spring 130 is also provided with arms 132 which are normally diverging as shown in Fig. 5. During assembly, it is so assembled with the other parts that one of the arms 132 engages a

lug

133 or 134 on the back bearing plate, and the remaining arm will engage the arm on the member 86. This brings the arms 132 closer together and the outward force of the arm against the

lug

133 or 134 and the arm 105' has a tendency to move the member 86 in one direction or the other depending on which side the spring is placed.

It will be appreciated that if this spring is removed, the rocker will remain in one extremity or the other until the shaft 60 is rotated by some external effort, but that when in place, the return spring causes the rocker to be automatically returned to its original position.

A center lug 135 on the back plate 68 engages the spring arm after it has forced the operating member 86 back to its original position, thereby maintaining the shaft in a pre-operative relationship and removing the pretravel portion of the stroke of the shaft so that the rocker can be rotated with a minimum of lost rotatable motion in said shaft.

Figs. 6 to 8 inclusive illustrate a modification of the switch of the invention, and along with Figs. 9 and 10, also show alternative forms as well as alternate arrangements of the fixed and movable contacts.

A change is made in the rocker structure, but this alteration does not change the manner in which it functions. In this case, the rocker which is preferably made of molded insulation material has incorporated therewith a metallic plate 209. The upper portion 210 of this plate is embodied in the body of the rocker and the lower part 211 lies on the surface of the stem and carries a round stud or projection 212 which corresponds to the boss 110 on the previously described embodiment. The lower end of this plate is provided with oppositely disposed notches 213 which act as seats for the pawls or dogs. The extremity of the plate is curved to conform to the end of the rocker as in the previous embodiment. The plate has an operative portion therein in alignment with holes through the mid portion of the cross beam 40 through which the rocker support pin may extend. The support pin in this case comprises a threaded shoulder bolt 215, the shoulder of which engages the center boss 41 and the threaded end of which may extend beyond the boss 41 and is locked by a lock nut 216. The head 217 holds the rocker on the pin. The above described plate provides a sturdier rocker and one with surfaces that resist wearing through long periods of use.

It will also be noted that the dogs 195 which correspond to those (95) of the original embodiment are also changed slightly. In this case, they are simpler in construction which is largely made possible by the use of a difierent type dog operating spring 199. The function is, however, the same. Each dog includes the rocker engaging arm 196 and the cam engaging arm 197. Each is held with the arm 196 pressed toward the end of the rocker by a coil spring 199 disposed about the dog support pin 96 and having a hook formed on one end hooked about the arm 197 and the other end extending tangentially from the body at 200 and engaging the boss 100.

Another improvement which also results in economies in manufacture resides in the operating shaft which, in this case, has a main body 161 hexagonal in cross sec tion. This eliminates the need for the keyways, since corresponding hexagonal holes are provided in the elements which turn with the shaft such as the cam 83 and the spring operating element 86. The openings in the other elements obviously are large enough to permit the shaft to move therein without causing them to turn. In this instance, the key washer 82 is not needed because the hexagonal body is larger than the stem 63 and a thrust washer 82 replaces it. Also, the end of the body is re.

t l duced at 167 to provide a bearing surface for engagement in the back bearing bracket 168. i

.The bearing .bracket1168 is also simplified inits .contour ascan best be seen in Fig. 6. .It retainsthe center lug 135 but eliminates the

arms

133 and 134. This is made possible by the substitution of .another type of

rocker returnspring 232for

130 and 132, which in this instance includes a helical body portion 230 of 1 /2 or more turns the ends 232 of which form arms one of which may engagethe rocker support pin while theother engages the luglOS on the springdrive element 86. The construction of this springreduces the tendency to breakage due to fatigue because of the greater number ofconvolutions possible in the body. The spring drive element 86 is changed slightly in that therotor return lever 105' israised to a higherplane thereby enabling a smaller spring pressure to return the rotor to. its original position.

As previously stated, any of the fixed contact strips may be removed ifdesired to .provide a versatile switch without. affectingthe efficiency of itsoperation. Fig. 9 shows the center strips removed. In this case, the outer contactsrare alternately made and broken when the rotor is operated.

The standard rotor contact 55 can. be removed and a contact 34, constructed of an insulating material and having only the central portion enclosedwithin the body of the rotor, canbe inserted in its place. The insertion of this dummy contact allows the same rotor contact spring assembly to be used .while having the rotor operable at only one position.

In Fig. 10, one of the outer contacts has been removed and the center contact is provided with a single angularlydisposed contact so that the .center and only one side set of contacts is used. It will also be noted that the movable contacts in this instance also take a different form, being flat rather than curved, and that the fixed contacts are curved. This permits a better wiping action between the contacts reducing the contact resistance. This .enables theuser to make the necessary changes to provide a switch that. can be used as .a double pole single throw ordouble pole double throw. Asshown in Fig. 10, both sets of. contacts can be wired into the same circuit. Thus, since they are in different planes, the likelihood of breaking the circuit in the presence of mechanical shock is substantially reduced.

Figs. 11 and 12 show a.rnodified form of back bearing plate and return spring which permits easier assembly and longer life for the spring.

The back plate issubstantially the same conformation as that of Fig. 6. At the point on the plate where the bearing surface is provided for the shaft 160, however, three equally spaced lugs 208 are struck and are bent normal to the plate. The spring 205 in this instance is provided with .a bent portion 210 which hooks over one of the lugsand then extends around the periphery of the other lugs for substantially one complete revolution. It then spirals outwardly for two. or more revolutions and terminates in a severely bent part 207 which engages with the lug 209 of the plate. The plateand spring may be assembled as shown in Fig. 11, and then by rotating the shaft to move the spring operation member 86 beyond the lug 209 of .the bearing plate and inserting the plate and spring, the spring is in position to pick up and engage the operation member when the switch is operated in the normal manner.

It will be :apparent that the return spring operates as such only between thelimits of its movementwhen turned by the operation member and returns the operation member to its normally neutral position at which time the spring 20$.engages the lug 209. on the bearing plate and over travel in that direction by the operator member is only resisted by therotor operating spring 90.

This structure enables the switch to be easily assembled, and it maybe assembled in the plate in the reverse direction to that shown when it is desired to have the spring return of the operating lever'and its shaft inthe other direction. It also enables the spring tension to be adjusted since the spring-end 210 may behooked over any one of the three lugs 209 on the bearing plate.

Inasmuch as the spring closely enfolds the lugs for one complete revolution and gradually spirals outward, there is realized a connection for the spring without sharp bends and therefore fatigue andbreakage is reduced to a minimum.

It should also be noted that the plates which close the front and back are secured in place by screws that are threaded into the bosses 72 and 72' which are provided with blind holes 11. A gasket is usually interposed between the plateand housing, and with thisconstruction a substantially moisture proof condition is realized.

It will thus be seen that .I have provided a switch which is exceedingly versatile and rugged as well as sim ple. The action is such that a quick make and break is possible and the parts may operate over a long useful life. and where breakages of the parts is reduced to a minimum due to the elimination of fatiguing parts. The construction of the rotor, with the head carrying the contactsand the stem with its included cam and dog plate, and the pivot being intermediate the head and stem, enables the same to be counterbalanced which not only affords a quicker operation but also help to eliminate bouncing upon making contact. It is also apparent that the versatility is increased by the ease of adjustment of both the contacts and the snap action mechanism, and that further the parts are readily accessible for examination or replacement should that be necessary.

Having thus described my invention, I am aware that numerous and extensive departures may be made therefrom withoutdeparting from the spirit of my invention as defined by the appended claims.

I claim:

1. An apparatus of the class described including spaced fixed contacts and movable contact carrying means for swinging movable contacts into and out of engagement with the fixed contacts, said movable contact carrying means being pivotally mounted and carrying the movable contacts on one end and having an operating stem comprising a projection, having curved surfaces and a portion extending beyond said projection and having dog engaging faces on opposite sides, spring means for engage,

ment with said projection on opposite sides thereof, means for increasing the pressure of said spring means on said projection including a shaft and a spring operating member connected to and rotatable with the shaft and engaging the spring means, means to hold said stem against movement by the spring means until a predetermined pressure is built up therein by said spring operating means comprising a pair of dogs disposed on opposite sides of said stern each dog having an arm for engagement with said dog engaging face on the stem and means for urging said dogs with the arm into opposition with said face and cam means connected to and rotatable with said shaft and having a cam thereon for alternate engagement with said dogs to move them out of engagement with said face.

2. An apparatus of the class described including fixed contacts and a movable contact carrier for moving movable contacts into contact with said fixed contacts said carrier being pivotally mounted intermediate its ends and having a head portion carrying the movable contacts and a stem portion for cooperation with an operating means, said stem portion including a projection on one side having curved surfaces for connection to a moving means and a second portion extending beyond the projection and formed with dog engaging faces on opposite sides, said moving means including a shaft, a spring comprising a circular body portion surrounding and freely movable relative to the shaft and having a pair of arms extending outwardly therefrom and in tangential engagement with the curved surfaces on said projection, means,

carried by said shaft for alternately moving said arms to stress said spring comprising a body in interlocking engagement with the shaft and having an offset arm extending between said spring arms, means to hold said stem portion against movement and to be released upon a predetermined movement of said shaft comprising a pair of dogs pivotally supported on opposite sides of said stem portion and each dog having an arm for engagement with one of said dog engaging faces on said stem portion and each dog having a second arm extending toward said shaft and spring means for biasing said dogs to move the face engaging arm opposite said face on said stem portion and cam means in interlocking engagement with said shaft having a cam surface for engagement with said second arm to alternately move said dogs out of engagement with the stem portion upon a predetermined movement of the shaft.

3. A switch of the class described including a housing having fixed contacts therein and a movable contact carrier for moving movable contacts into circuit making and breaking engagement with the fixed contacts, said movable contact carrier comprising a member pivotally supported by the housing intermediate its ends and having a head portion for carrying the movable contacts and a stem portion on the opposite end for cooperation with a snap action mechanism, said stern portion including a projection protruding from one side of the stem portion and adapted to cooperate with an operating spring, said stem portion extending beyond the projection and provided adjacent its end with dog engaging faces, said housing being provided with a bearing boss below said stem portion and an operating shaft journalled in said boss, said operating spring including a body portion disposed around said shaft and having a pair of arms extending outwardly therefrom and each being in tangential engagement with said projection on opposite sides thereof, a spring operating member disposed in interlocking engagement and movable with said shaft and having an offset arm extending between said spring arms adapted to alternately engage one or the other of said spring arms upon rotation of the shaft and upon movement by one of said spring arms, the other spring arm adapted to exercise increasing pres-v sure on said projection, and means to hold said stem portion against movement in the face of increasing spring pressure comprising a pair of dogs pivotally connected to said housing on opposite sides of said stem portion, each of said dogs having an arm for alternate abutting engagement with said dog face on said stem portion and each having spring means engaged between each dog and the housing wall for urging said dogs for operative holding engagement with said stem portion, and a cam member disposed in interlocking engagement with said shaft and having a cam surface for alternate engagement with said dogs to move them alternately out of locking engagement with the stem portion.

4. A switch of the class described including a housing having fixed contacts therein and a movable contact carrier for moving movable contacts into circuit making and breaking engagement with the fixed contacts, said movable contact carrier comprising a member pivotally supported by the housing intermediate its ends and having a head portion for carrying the movable contacts and a stem portion on the opposite end for cooperation with snap action mechanism, said stem portion including a projection protruding from one side of the stem portion and adapted to cooperate with an operating spring, said stem portion extending beyond the projection and provided adjacent its end with dog engaging faces, said housing being provided with a bearing boss below said stem portion and an operating shaft journalled in said boss, said operating spring including a body portion disposed around said shaft and having a pair of arms extending outwardly therefrom and each being in tangential engagement with said projection on opposite sides thereof, a spring operating member disposed in interlocking engagement and movable with said shaft and having an offset arm extending between said spring arms adapted to alternately engage one or the other of said spring arms upon rotation of the shaft and upon movement by one of said spring arms, the other spring arm adapted to exercise increasing pressure on said projection, and means to hold said stem against movement in the face of increasing spring pressure comprising a pair of dogs pivotally connected to said housing on opposite sides of said stem portion, each of said dogs having an arm for alternate abutting engagement with said dog face on said stem portion and each having spring means engaged between each dog and the housing wall for urging said dogs for operative holding engagement with said stem portion, and a cam member disposed in interlocking engagement with said shaft and having a cam surface for alternate engagement with said dogs to move them alternately out of locking engagement with the stem-portion, and means for supporting an end of said shaft comprising a plate seated on the housing wall and having an opening for receiving the end of the shaft, and means for biasing the shaft to an extreme rotated position comprising a second spring having a body disposed about the shaft and a pair of outwardly extending arms prestressed to an open position and a second offset arm on said operating member engaged on the outside of one of said spring arms and means on said plate disposed for engagement with the other arm, said arms when disposed between said second offset arm and said lug being tensioned to move said second arm away from said lug.

5. A switch including spaced apart fixed contacts and a swingable contact carrier arranged to be swung to bring movable contacts into contact with the fixed contacts, said swingable carrier including a head portion for supporting the movable contacts and a stem part projecting from said head, pivot means for pivotally supporting the carrier below said head and spaced from the end of the stem part, said stem part being provided with a plate embedded in the stem part and having a part coextensive with the end of the stem part supporting an operating pin and formed to provide pawl engaging seats, means for engagement with said stem part to swing the carrier ineluding an operating shaft, a spring 'having a pair of arms engaging said operating pin, a lever connected to said shaft and having a portion extending between said spring arms and movable to move one of said arms away from said spring and toincrease the tension on the other arm, a cam carried by said operating shaft, a pair of pawls each engageable with said stem part upon movement to alternate positions, said cam means being arranged for alternate engagement with said pawls to release said pawl from holding engagement with the stem upon a predetermined movement of the shaft.

6. A switch including spaced apart fixed contacts and a swingable contact carrier arranged to be swung to bring movable contacts into contact with the fixed contacts, said swingable carrier including a head portion for supporting the movable contacts and a part projecting from said head, pivot means for pivotally supporting the carrier below said head and spaced from the end of the head and said projecting part, said part being provided with a plate embedded therein and having a part coextensive with the end of the part supporting an operating pin and formed to provide pawl engaging seats, means for engagement with said part to swing the carrier including an operating shaft, a spring having a pair of arms engaging said operating pin, a lever connected to said shaft and having a portion extending between said spring arms and movable to move one of said arms away from said spring and to increase the tension on the other arm, a cam carried by said operating shaft, a pair of pawls each engageable with said pawl seat upon movement to alternate positions, said cam means being arranged for alternate engagement with said pawls to release said pawl from holding engagement with the part upon a predetermined movement of the shaft.

7. An, operating means for a switch including a housing 11 having ea and s e walls d ha ing fi co ests d a mo e o act ry n member fo inst 2 s movable contacts into and out of engagement with the fi e contacts, s ovable c ntact me be issli di a rotor having a ad portion o upp rtin the movab contacts, and Pivot m ans tf r p votally suppo t n said member i r e at its e d said embe ha ing an r s Stem spo n the opposi e ides aid Pi ot t0 the contacts and including a plate -emhedded iii-the stem ins a P otect n hereon fo en a e ent a moving means and seatsdjsposed below the projection for a stern holding means, said moving means including an operating shaft journalled in the front wall and a bean s plate e a e d of e s a t a oper ing member carried y said sh and c nnec ed h re n w tatable therewith and having an outwardly extending p n pera ng memb a p in inc d n a od p0 tion surrounding the shaft and having outwardly extending arms which are tensioned by the body portion to resilicntlyforce the arms toward each other, said arms being in engagement with the projection on said stem and said operating member extending between said spring arms and arranged to increasethe pressure ,of one of said spring arms on said projection by moving the other spring arm away from the projection, pawlmeans supported by said housing on opposite sides of said housing and each having a portion for engagement with said stem when the stem is moved furthest away from the pawl support, and cam means connected-to and rotatable with said operating shaft and arranged to engage said pawl and release it from said seat on said stem :upon a predetermined movement of said shaft,

8. A switch comprising a housing including sidewalls, a fixed contact carrier disposed in the one end of said housing and supporting fixed contacts in spaced relation to each other, a bridge portion for said housing disposed spaced from said fixed. contacts and a movable contact carrier-for carrying and movingmovable contacts into and out of contact with the fixed contacts pivotally supported on said bridge, said movable contact carrierhavingaportion extending from said pivot point toward the other end of the housing and being .formed on the end with pawl engaging seats and having an outwardly extending projection above said seats, means for moving the carrier between alternate positions including a shaftrotatably disposed inrthe end of the housing, spring means;for excrting pressure on opposite sidesof said projection engaging said boss, a springtensioning mcmberconnected to, said shaft and having apportion arrangedfor alternate engagement with said spring means to moveone part away from the projection and increase the pressureon the other part, pawl means disposed on opposite sides of the housing and havingtpawl arms each arranged to alternately engage said seats, cam.mcans on said shaft arranged for alternate engagement with said pawlsto. release said: pawls from holding engagementjupon predetermined rotation of theshaft.

9. Aswitch comprising, a'housing includingrside walls, a fixed contact carrier disposed in the one ,end of said housing and supporting fixed contacts in spaced relation to each other, a bridge portion for said housing disposed spaced from said fixed contacts and armovable contact carrier for carrying and moving movable contacts into and out of contact with the fixed contacts pivotally supported on said bridge, said movable contact carrier having a por jection and increase the pressure on the other part, pawl means disposed on opposite sides of the housing and having pawl arms each arranged to alternately engage said seats, cam means on said shaft arranged for alternate engagement with said pawlsto release said pawls from holding engagement upon predetermined rotation of the shaft, a second spring means for said shaft including a spring surrounding the shaft and having an end connected with the housing to hold it against movement and another end for engagement with said tensioning member.

10. A switch comprising a housing including side walls, a fixed contact carrier disposed in the one end of said housing and supporting fixed contacts in spaced relation to each other, a bridge portion for said housing disposed spaced from said fixed contacts and a movable contact carrier for carrying and moving movable contacts into and out of contact with the fixed contacts pivotally supported on said bridge, said movable contact carrier having a portion extending from said pivot point toward the other end of the housing and being formed on the end with pawl engaging seats and having a projection on the side above said seats, means for moving the carrier between alternate positions including a shaft rotatably disposed in the end of the housing, spring means for exerting pressure on opposite sides of said projection engaging said projection, a spring tensioning member connected to said shaft and having a portion arranged for alternate engagement with said spring means to move one part away from the projection and increase the pressureon the other part, pawl means disposed on opposite sides of the housing and having pawl arms each arranged to alternately engage said seats, cam means on said shaft arranged for alternate engagement with said pawls to release said pawls from holding engagement upon predetermined rotation of the shaft, a second spring means for said shaft including a spiral spring surrounding said shaft and having an inner end connected to said housing to hold it against movement and the other end connected to said spring tensioning member.

11. A switch comprising a housing, fixed contacts supported in spaced relation to each other in oneend of the housing, movable contact means pivotally supported from the housing and having movable contacts swingable into and out of engagement with said fixed contacts said movable contact means having an operating portion extending from said pivot point opposite to the contact carrying end andincluding a part having pawl engaging faces formed on opposite sides, a projection formed on the face of saidtpart, pawls pivotally arranged on opposite, sides of the housing andthaving spring means foreach pawl to urge it into engagement with one of said seats, said pawls being disposed to hold the operating portion in alternate extreme positions against swinging, means for engagement with said projection to exert spring tension thereon including a shaft rotatably journalled in the lower part of the housing, aspring surrounding said shaft and having a pair of outwardly extending arms engaging said projection and exerting spring. tension on opposite sides thereof, means to increase thespring tension on one of the arms comprising a lever keyed to the shaft and having an offset arm disposed between said spring arms and movable with said shaft to move one of the other of said arms away from the projection and increase the pressure on the other arm, a pawl release member for alternately releasing said pawls and permitting the spring to move the operating portion to another position secured to said shaft and having a cam surface for engagement with an operation of said pawls, means to return said shaft to its original position comprising a. spring having one end in engagement with the housing, a plate disposed in the housing and having a lug extending inward toward the operating member, one end of said shaft return spring being engaged with said lu'g and arranged to be engaged by said operating member to extend pressure against the Operating member when it is moved and to return it to 2,459,077 Jeffrey Jan. 11, 1949 its original position. 2,513,952 Minneci July 4, 1950 2,620,417 Lewis Dec. 2, 1952 References Cited in the file of this patent FOREIGN PATENTS UNITED STATES PATENTS 5 274,547 Germany May 28, 1914 2,326,011 Currie Aug. 3, 1943 391,323 Great Britain Apr. 27, 1933 2,352,815 Van Valkenberg July 4, 1944