US2285210A

US2285210A - Electric switch

Info

Publication number: US2285210A
Application number: US358860A
Authority: US
Inventors: Leslie A Kempton
Original assignee: EDISON GENERAL ELEC APPLIANCE
Current assignee: EDISON GENERAL ELEC APPLIANCE; EDISON GENERAL ELECTRIC APPLIANCE COMPANY Inc
Priority date: 1940-09-28
Filing date: 1940-09-28
Publication date: 1942-06-02
Anticipated expiration: 1959-06-02

Description

June 2, 1942. L. A. KEMPTQN 2,285,210

ELECTRIC SWITCH Filed sept. 28, 1940 2 sheets-sheet 1 111 vehtor: Leslie A. Kem pboh,

H is Attorhefg.

Jun? 2, 1942. L. A. KEMPToN l ELECTRIC SWITCH Filed sept. 2s, 1940 2 Sheets-Sheet 2 ...u m -t n vnl r. ...om .w m3.. e. A VA 5 ...11n .l E WH L if Figsll.

Patented June 2, 1942 ELECTRIC SWITCH Leslie A. Kempton, Chicago, Ill., assignor to Edison General Electric Appliance Company, Inc., Chicago, Ill., a corporation of New York Application September 28, 1940, Serial No. 358,860

(Cl. ZOO-6) 5 Claims.

This invention relates to electric switches and more particularly to multiple-position electric switches and has for its object the provision of an improved device of this character which can be manufactured at low cost.

In multiple-position electric switches it is customary to provide special contact means formed of material capable of resisting pitting by the arcs formed upon the making or breaking of the circuit being controlled. In many instances the contact means is in the form of contact buttons made of silver which is known to have the desirable arc resisting properties. Such special contact means, and especially those in the form of precious metal contact buttons, usually represent a large proportion of the cost of a particular switch and this is especially true in multiple-position switches which are used for domestic cooking appliances. Thus if the number of such special contact means required for a particular multiposition switch could be reduced a substantial saving in the cost of the switch could be made.

It is the specic object of this invention to provide a new and improved multiple-position switch in which the number of special arc resisting contacts used may be substantially reduced without affecting the number of control positions of the switch. Expressed differently, it is the specific object of this invention to provide a multiple-position control switch with a reduced number of special arcing contacts and with means for controlling the sequence of operation of the contacts so that when the switch is moved to its different circuit controlling positions the various circuits will be made or broken at the arcing contacts provided.

While not limited thereto, this invention is particularly applicable to multiple-position switches of the type described and claimed in United States Patent 2,203,236, issued June 4, 1940, on an application filed by Charles P. Randolph and me and assigned to the assignee of the present invention. While such multiple-position switches have many uses, they are particularly applicable for controlling electric range heating circuits as described in the aforementioned patent. In accordance with this invention there is provided in a switch of this type a plurality of arcing contacts made of suitable arc resisting material such as silver, and a plurality of non-arcing or circuit changing contacts made of a suitable base metal capable of carrying the load current. Ineluded with this contact construction is new and improved means for controlling the sequence of operation of the contacts so that the load circuits are always made or broken at the arcing contacts as will more fully appear hereinafter.

For a more complete understanding of this invention reference should be had to the accompanying drawings in which Fig. 1 is a front elevation of an electric switch embodying my invention; Fig. 2 is a rear elevation of the switch shown in Fig. 1 with a part removed so as to illustrate certain details of the construction; Fig. 3 is a sectional view taken on the line 3--3 of Fig. 2 and looking in the direction of the arrows, the switch of Fig. 3 being shown mounted on a supporting panel; Fig. 4 is a partial sectional View taken on the line 4--4 of Fig. 2 looking in the direction of the arrows, showing details vof the contact structure of this invention; Fig. 5 is a view taken on the line 5--5 of Fig. 3 looking in the direction of the arrows, parts being removed to show details of the cam construction; Figs. 6 and 7 are developed sectional views taken on the lines 6-6 and l-l respectively of Fig. 5, looking in the direction of the arrows and showing details of related portions of the cam construction; Fig. 8 is a View similar to Fig. 4 showing a modified form of contact structure; Fig. 9 is a perspective view showing additional details of the modied form of contact structure shown in Fig. 8; Figs. 10-15, inclusive, are diagrammatic representations of the switch shown in Figs. 1-7 showing the switch controlling a heating element having two resistances to provide various degrees of heat; and

Figs. 16-21, inclusive, are sectional views taken on the lines IS-IB through 2I-2I of Figs. 10-15 respectively showing the position of the contact members in each position of the cam member illustrated in Figs. 10-15.

Referring to the drawings, my invention has been shown in one form as applied to a multipole switch intended to `control the heating circuit of a surface unit of an electric range. As illustrated in Figs. l-3, this switch comprises a supporting panel I0 formed of some suitable insulating material such as a. phenol condensation product. This supporting panel is provided with a peripheral flange I I which defines a rectangular-shaped chamber I2. Mounted within the chamber at one end thereof, the lower end as viewed in Fig. 2, and secured to the panel by means of rivets is a series of line terminals I3, I4 and I5. The horizontal portions of these terminals extend along the lower end of the chamber I2 and are provided with pairs of contacts I6 and I1, I8 and I9, and 20 and 2I, re-

spectively, which will be described more fully hereinafter. The vertical portion of the line terminals I3--I5 projects beyond the lower wall of the chamber so that connections can be made exteriorly of the chamber with a suitable source of supply (not shown). In .order to facilitate making electrical connections, the terminal members I3, I4 and I5 are suitably bent so that the ends thereof lie in different planes, as shown in Fig. 3. Molded in the upper flange surface of the supporting panel is a plurality of openings 22 in each of which is provided a load terminal screw 23 which is secured in position by means of a nut 24 and to which is adapted to be lconnected the load being controlled.

Secured to the upper end of the chamber I2 by means of rivets 25 is a plurality of contact fingers 2li-SI, inclusive, which are made of a suitable resilient, electrically conducting material, such as phosphor bronze, and are interposed between the line terminals I3, I4 and I5 and the load terminals 23 to control the transfer of power therebetween. Referring to Fig. 2, itV will be observed that the contact finger 28 is provided with a portion 32 which projects through the top wall of the chamber 'and terminates under the extreme right terminal screw 23, as viewed in Fig. l, to form an .electrical connection between Vthe screw and the main portion of the contact The

contact lingers

21 and 28, on the e finger 25. other hand, are formed from a single strip of material and the-fingers are in effectV legs of a substantiallyY U-shaped strip having aV bridging -portion 33. Projectingoutwardly from the bridging portion, in line with the contact finger 28 is a portion 34 which is fastened under the second terminal screw 23 Vfrom the right, as viewed in Fig. ,1,A to form an electrical connection between this load terminal` and the

contact fingers

21 and 28. The contact fingers 29 and 3U are similarly formed froma single piece of substantially U-shaped material which also is provided with a portion 35 which extends outwardly through the top'wall of the chamber and is fastened under the third terminal screw from the right, as viewed in Fig. l, to form the electrical connection betweenthe contact ngers V29 and 30 andthe terminal screw 23. The contact finger 3-Iv is similar to the linger 26 and is provided with a portion 35 which extends outwardly through vthe top wall of the chamber and is fastenedunder the eXtreme left-hand terminal 23 viewed iny Fig. l to form an lelectrical connection v therewith. In order to maintain the various terminal lingers in their relatively spaced positions, a plurality of bosses 31 are molded in the bottom wall of the chamber I2 so as to lie between adjacent contactV ngers.

In order to provide an electrical connection between the contact iinger 3| and the pair of iingers 21 and v28; there is provided a U-shaped shunt strip 33 made of a suitable conducting material. `The legs of this shunt strip are secured under the nuts 24 Vof the terminal members 23 so that the shunt is 4spaced from the contact fingers and lies near the top of the chamber I2, as vshownV in Fig. 3. Moreover, as shown in Fig.

'3, the chamber I 2k is closed by a cover I2a formed by a plate of Asuitable electrically insulating maf te-ri'al which is secured to the panel I0 by means of 4rivets or sorneother suitable fastening means.

In order that the contact fingers may perform their circuit lcontrolling and v circuit changing functions 'eife'ctivelv each finger is provided with a Acontact which cooperates with a corresponding contact provided on the line terminal members I3-I5. In the usual switch construction, both the line contacts and the contacts on the fingers are made of a'suitable material capable-of withstanding the arcs which occur upon the making or breaking of the load circuit. Contacts made Y sible to effect a reduction in the number of these silver contacts required without affecting the life or reliability of the switch, the cost of a switch can be materially reduced. y

In accordance with this invention, I have provided a new and improved switch construction by v which such a reduction in silver contacts can be effected. Considered generally I have provided a multi-position multi-pole switch in which only a certain number of contacts are `made from arcresisting materials, `such' as silver and the like, and these are termed arcing'contacts. l The remainder of the contacts are made of,` a base material capable-of carrying the load current and are termed non-arcing contacts. of operation of these contacts is then controlled by a new and improved cam member so that 4the circuits being controlled are made andA ybroken at the arcing contacts whereas'the non-arcing contacts serve merely ascircuit changing contacts. In other words, I have provided` inconjunction with my improved contact arrangement, new and improved means f'or controlling 'the sequence of operation of the contactsso that upon the making of the various circuits controlled by the multiposition switch, the arcing contacts, i. e., lthosema-de of a material capable of withstanding the arc generated, are closed after the non-arcing or circuit vchanging contacts are closed, and, upon'the breaking of the various circuits, the arcing contacts are Iopened before opening of the non-arcing contacts.

Turning now to the specific embodiment of my invention shown in the drawings and referring to Fig. 4, itwill be observed thatl the-terminal member I3 is provided with a pair of arc-resisting contact abutments, VIn the preferred form of this invention, these abutments, as well'as the remainder of the arc-resisting abutments tobe described hereinafter, arefin the form of silver contact buttons. If desired, however, these silver contact buttons could be replaced by` a silver inlay or a heavy silverplatedirect Von the contact fingers or by suitable non-metallic arcresisting abutments such as `carbon ,Contact buttons. Arranged to cooperate with the silver contact buttons on the terminal'member I3 is a pair of silver contact buttons V39 and 40 which are welded or otherwise securedtoV the contact fingers 2S and21, respectively. In additionto these pairs of arcing' contacts, there is one other pair of arcing contacts which arelikewise formed byV 'These'f'contactsalr thereforabe'` made from a base' material such asphosphor bronze and asA shown in Fig. 4 they'are preferably formed by The sequencel pressing integral bosses I8, I9 and 2| in the line terminals I4 and |5 against which the end of the

contact fingers

28, 29 and 3| are adapted to bear to form pairs of contacts |8-28, |9--29 and 2 |--3|, respectively. These pairs of contacts may be designated the non-arcing or circuit changing contacts since the only function they serve in the switch is to vary the circuit relations of the circuits controlled by the switch. In order to protect the non-arcing contact members from oxidation and corrosion during use, it has been found desirable to provide on these contacts a light silver flash or coating. However, it is to be understood that such a coating is merely provided to increase the life of the switch as a whole and may be omitted without affecting the operation of the switch,

In order that the travel of the non-arcing contacts between their opened and closed positions may be the same as the travel of the arcing contacts, the entire horizontal portion of the terminal member |4 and the portion of the terminal member I5 in which is formed the non-arcing contact 2| are offset as shown in Figs. 2 and 4 to bring the non-arcing contacts provided in the terminal closer to the

contact fingers

28, 29 and 3|, In Figs. 8 and 9 I have shown a modied form of non-arcing contact structure which may be employed. In this modified form it is possible to arrange the horizontal portions of the terminal members |3, Ell and l5 in a line as shown in Fig. 8. This is made possible by forming in the end of the

terminal members

28, 29 and 3| substantially

cylindrical bosses

42, 43 and 44 which cooperate, respectively, with the bosses |8, I9 and 2| provided in the terminal members |4 and I5.

As shown in Fig. 4, the contacts of the multiposition switch have a normally opened position and are moved to the closed position upon the movement of the contact iingers 26-3|. Provided in a series of horizontally aligned apertures in the panel lli is a series of pins 45-5|l. These pins, when forced inwardly or to the right as shown in Fig. 3, engage the ngers 26-3I, respectively, to move them outwardly in a direction to cause the contacts mounted thereon to engage the respective contacts on the line terminals I9|5. The movement of the pins 45-50 is controlled by a cam 5| which preferably is in the form of a flat disk-like metallic member although this cam may be made from any other suitable material.

In order to control the sequence of operation of the pins 45-50 so that the circuit connection between the line and load terminals of the switch will be made at the arcing contacts after closing of the circuit changing contacts and will be broken at the arcing contacts before opening of the circuit changing contacts, there is formed in the cam 5I a series of arcuate depressions which lie in radial spaced relation so that one depression or group of depressions is provided for controlling each of the actuating pins in the switch. Referring to 5, it will be observed that the pin 50 for actuating the contact finger 3| is controlled by the outermost arcuate depression 52 which is broken by a single flat surface 53; that tuating the contact nger 2'| is controlled by the arcuate depression 66 which is separated by a single flat surface 61; that the pin 48 for actuating the Contact finger 29 is controlled by the arcuate depression 68 which is separated by the single elongated flat surface E9; and that the pin 4l for actuating the contact nger 28 is controlled by the arcuate depression 'l0 which is separated by a single flat surface 1|, The length of the arcuate depressions and the relative position of the at surfaces which separate these depressions is designed so that, in operating the switch, at least one of the pins 45, 46 and 49 for the contact fingers 25, 2l' and 30, respectively, will be actuated to close one pair of arcing contacts after the pins 4l, 48 and 59 for the contact fingers 29 and 3l, respectively, have been actuated to close the non-arcing contacts upon the making of a particular circuit and at least one of the pins 45, 46 and 49 will be actuated prior to movement of any of the pins 41, 48 and 5|) to open the arcing contacts ahead of the non-arcing contacts upon breaking of a particular circuit. In other words, the cam surface is so developed that the

contact fingers

26, 21 and 30 will be the last to be moved when a circuit is being made and first to be moved when a circuit is being broken.

It is to be particularly noted as shown in Fig. 5 that the means for operating the contact finger 25 comprises a series of arcuate depressions which are separated by flat portions Whereas the means for operating the remaining Contact fingers comprises a single arcuate depression which is separated by a single flat portion. Thus it will be observed that the contact nger 26 which is one of those provided with precious metal contacts will be operated in every position of the switch either to make or break the load circuit.

As has already been pointed out, the

pins

45, 45 and 49 control the contact fingers which operate the arcing contacts of the switch whereas the

pins

41, 48 and 56 control the contact fingers which operate the circuit changing contacts for the switch. In order to insure that as the switch is moved from one position to another the arcing contacts will be operated in their proper sequence relative to the non-arcing contacts, the ilat surfaces of the cam over which the pin for operating the non-arcing contacts must pass is made longer than the nat surfaces over which the pins for the arcing contacts must pass. The details of this construction are clearly shown in the developed sectional views shown in Figs. 6 and 7 Referring to these views, it will be observed that the fiat surfaces 69 over which the pin for the non-arcing contact 29 passes begins well in advance of the flat surface 59 over which the pin for arcing Contact 29 passes and terminates well beyond the end of the hat surface 60 over which the pin for the arcing contact 26 passes. By this construction it is positively assured that the non-arcing contacts will be moved before the arcing contacts upon circuit making and after the arcing contacts upon circuit break. It will, of course, be understood that the relation shown in Figs. 6 and 7 obtains for the remaining arcing and non-arcing contact means.

As is clearly shown in Fig. 3, the cam 5| is rigidly secured to an operating shaft 'F2 which is journaled at its inner end in a bearing 13 provided for it in the panel lil and at its outer end in a bearing 'i4 provided for it in a cupshaped cover member 'I5 which houses or encloses the cam. In order to secure the housing 15 to the panel I9, there is provided on the edge of its side wall a pair of oppositely spaced fingers l'I6 which are secured to the panel by means of rivets 11.

In order to hold the cam 46 in anyparticular selected controlling position, a positioning member 18 is provided which is secured to the shaft 12 by means of a splined connection (not shown) .f

positions are substantially 69 degrees apart.V

Mounted on opposite sides of the positioning cam is a pair of flat springs 89 which at'their opposite ends are secured to opposite sides of the housing 15, as shown in Figs. 1-3. For this purpose the springs 89 are provided at their ends with eXtensions 8l which are directed 'through apertures provided for them in the housing. The upper and lower ends of the springs, as shown in Fig. l, are spaced sufliciently close together so that the central sections of the springs are pressed against the sides of the positioning member thereby to hold it resiliently in any controlling position to y which it is moved.

lWhen the switch is used to control the surface unit of an electric range, it will normally be mounted on a panel 92 at the iront of the range so that the shaft '12 extends outwardly therefrom. Mounted on the projecting end of this shaft is a knob 83 by which the switch may be readily operated to its various circuit controlling positions. As shown, the knob may have a substantially triangular shape in order to provide a visible indication of the circuit controlling position of the switch. In practice, the casing of the switch is used for mounting the switch on a panel 82 and for this purpose it is provided with a pair of threaded apertures into which screws 84 are threaded as clearly shown in Fig. 3.

The switch of Figs. 1-'7 is diagrammatically shown in Figs. 10-15 as controlling the energization of a heating unit, such as the surface unit of an electric range, having two resist-ance ele-- m-ents 85 and 85 which are energized from a suitable source of supply. As shown in Figs.

l0l5, the unit is connected through the switch to a three-wire supply source 8?, 85 and 99 which provides two diiferent voltages which may be impressed ony the heating unit. The wires 'i and 38 are outside wires of this source while the wire 89 is the neutral and the voltage between the two outside wires is substantiallyV twice the voltage between any one outside wire and the neutral. As shown, the outsideV er left-hand end of the resistance 85 is connected through a load terminal to conducting strips lili and 13? and the outside end of the resistance is connected through a load terminal to the strip 32. The opposite ends of the units g5 and :ES are connected together and the common connection is connected through a load terminal to the conducting strip 35. The three line terminals I"- 5 and their corresponding pairs of contacts are connected as shown to the three wires iL-159 respectively.

In considering the operation of my improved multi-position'switch reference will be had to Figs. 10-15 which diagrammatically show each circuit controlling position of my improved multiposition switch and to Figs. 16-21 which are sectional views through the pin actuators showing the position of the cover, pins and contacts of the switch for each circuit condition ydiagrammatically represented in Figs. 10-15 respectively.

Referring first to Figs. 10 and 16, these views show the off position of the switch. be observed that the pins i5- 59 are each located in their respective depressions in the cam so that they are in their retracted position. Thus all of the switch contacts are in their normally open position and no energy is transferred from the line to the load. ItV will be noted that in this position the heating elements 85'and 39 are completely isolated from the power 'supply conductors because of the multi-pole switching arrangement. This is a desirable feature and is often required for safety purposes. p

Assuming now that the knob 83 is rotated clockwise from the position shown in Fig. lV to the next succeeding indexed position, the cam 5i will be rotated clockwise through approximately 6i) degrees to the position shown in Fig, 1l. In this movement of the Vcam the

pins

47, 49 and 59 4for the

contact fingers

28, 30 and 3l remain in their retracted position. However, during the rst part of this movement, the pin t8 of the contactnger 29 moves out of its depression 68 and up onto the iiat surfaceV 69 so that the nonarcing contacts l!) and 29 are closed. As the movement continues, the pin 65 for the contact finger 2 moves out'of its depression di and onto the flat surface `fi so that the arcing contacts l1 and are closed and the pin 45 for the linger 29 moves out of the depression 513 and onto the flat surface 59 so that the arcing contacts I5 and 39 are closed. The position of the contacts in this position of the cam is shown in detail in Fig. 17. l/Vith the contacts in the position illustrated itv will be apparent from Fig. 1l that the two v heating elements and 86 are placed in parallel across the outside wires 8l and 88 so thata maximum heat output is obtained. This position of the switch is termed the high heat or speed position.y

VAssume now that the switch is turned to its next indexed position which corresponds to a rotation of the knob 83 and the lcam 5l clockwise through an additional 6G degrees. In the first part of this movement the actuating pin for the Contact finger 25 moves off thefat surface 59 and into the next succeeding depression causingV the arcing contacts I5 and 39 to be opened, thus opening the circuit of the heating element S6. As this clockwise movement increases, the operating .pin 45 of the contact ringerr remained on the flat surface 69 so that the nonarcing contacts i9 and 29 remain closed during the switching movement as is clearly shown in Fig. 6. With the contacts I9 and 29, l5 and 39 closed as shown in Fig. 18, the heating element t8 alone is connected across the

outside wires

81 and 88 as is clearly shown in Fig'. l2 to produce the half speed position of the switch. Y

It Will f Assume now that the switch is advanced from the half speed position to the next succeeding indexed position which corresponds to moving the cam I through an additional 60 degrees. In this movement the first operation which takes place is that the pin 45 for the contact nger 26 moves off the fiat surface 6D and into the next succeeding depression 56 to cause the circuit for the heating element 85 to be opened. After the pin 45 has moved into the depression -56 and as the movement further continues, the operating pin 48 for the contact finger 29 moves off the fiat surface 69 and into the depression 68 to cause the non-arcing contacts I9 and 29 to be opened and simultaneously the operating pin 41 for the contact finger 28 moves out of the depression 10 and onto the fiat surface 1I to cause the non- -arcing contacts I8 and 28 to be closed. Upon the final movement of the cam to this third position, the pin 45 for the contact finger 26 moves out of the depression 56 and onto the fiat surface 6I to cause the arcing contacts I6 and 39 to be closed. With the contacts I8 and 42 and I6 and 39 closed as shown in Fig. 19, it will be observed from Fig. 13 that the heating elements 85 and 86 are placed in series across the

outside wires

81 and 88 to produce a quarter heat position of the'switch.

Assume now that the switch is advanced from the quarter heat position t0 the next succeeding indexed position which corresponds to a rotation of the knob 83 and the cam 5I through an additional 60 or through an angle 240 degrees from the off position shown in Fig. 10. In the first part of this movement the pin 45 for the contact linger 26 moves off the fiat surface 6I and into the. depression 51 to cause opening of the arcing contacts I6 and 39 thereby opening the heating -circuit of the series connected elements 85 and 86. As the movement continues, the pin 41 for the contact finger 28 moves off the flat surface 1I and into the depression 10 to cause opening of the non-arcing contacts I8 and 28. As the movement advances still further, the pin 49 for the contact finger 30 moves out of the depression 64 and onto the flat surf-ace 65 to cause closing of the arcing contacts 20 and 4I `and the pin 45 for the contact finger 26 moves out of the depression 51 and onto the fiat surface 62 to cause closing of the arcing contacts I6 and 39. With the contacts I6 and 39 and the contacts 20 `and 4I closed as shown in Fig. 20, it will be observed from Fig. 14 that the heating element 86 is now connected across the outside wire 81 and the neutral wire 89 and is thus energized at substantially half the voltage between the two outside wires so as to produce the thrift heat position of the switch.

Assume now that the switch is advanced from the thrift position to its next succeeding indexed position which corresponds to rotation of the knob 83 and cams 5I through an additional angle of 60 degrees. In the first part of this advance the pin 45 for the contact finger 26 moves off the fiat surface 62 and into the next succeeding depression 51 to open the arcing contacts I6 and 39. As the movement continues, the pin 49 for the cont-act finger 30 moves off the flattened portion 65 and into the depression 64 to :cause opening of the arcing contacts 4I and 20. Upon la still further advance, the pin 50 for the contact finger 3I moves out of the depression 52 and into engagement with the fiattened surface 53 to cause closing of the non-arcing contacts 2I and 3I and subsequently the pin 45 for the contact finger 26 moves out of the depression 58 and onto the flat surface 63 to cause closing of the arcing contacts I6 and 39. With these pairs of contacts closed as shown in Fig. 21 it will be observed from Fig. 15 that the heating elements 85 and 86 are connected in series across the outside wire 81 and the neutral wire 89 to produce the lowest heat output for the circuit which is termed the Warm position of the switch.

By advancing the switch to the next indexed position the knob cam will have been rotated through 360 degrees and hence will be in return the off position shown in Fig- 10. In the first part of this movement to the off position, the pin 45 for the contact finger 26 will move ofi the flattened surface 63 and into the depression 54 to cause opening of the contacts I6 and 39. 'Then as the advancing movement continues, the pin' 5D for the Contact finger 3| will move off the fiattened surface 53 and into the depression 52 to cause opening of the non-arcing contacts 2| and 3|.

Through all of the above multi-pole switching and circuit changing operations as the switch is moved through its six positions, it will be observed that in every instance the non-arcing contacts are closed before the arcing contacts upon the making of a circuit and the arcing contacts are opened before the non-arcing contacts upon the breaking of a circuit. Thus any arcing which occurs upon the closing or opening of the circuit will take place at the silver arcing contacts and the base metal non-arcing contacts serve merely as circuit changing contacts.

From the foregoing detailed description it will be observed that I have provided a new and improved multiple-positioned switch construction which can be manufactured at low cost, the salient cost reduction being produced by so constructing and arranging the switch that the number of precious metal contacts used thereiny may be substantially reduced and in the case of a six-position switch may be reduced by half.

While I have shown and described a particular embodiment of my invention, it will be understood. of course, that I do not intend to be limited thereto since many modifications can be made. I, therefore, contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l.. A multi-position multi-pole switch comp-rising an insulating supporting panel, a plurality of resilient contact fingers mounted on said panel. a plurality of pairs of relatively movable contacts comprising relatively fixed contacts mounted on said panel and relatively movable contacts carried by said contact fingers, said pairs of contacts including at least one pair of arcing contacts and at least one pair of nonarcing contacts, means comprising a rotary operating cam having cam surfaces for actuating said fingers to close said pairs of contacts when said cam is rotated, said cam having at least one switch closing position in which a plurality of pairs of said contacts including at least one pair of arcing contacts and one pair of nonarcing contacts are closed to effect a multi-pole switching function, said cam surfaces being arranged so that upon movement of said cam to said switch closing position the arcing contacts are closed subsequent to the non-arcing contacts and upon movement of said cam from said switch closing position said arcing contacts are opened prior to said non-arcing contacts whereby arcing occurs only at said arcing contacts.

`2. A multi-position multi-pole switch comprisingan insulating supporting panel, arplurality of normally open pairs of relatively movable contacts mounted on said panel, said pairs of contacts comprising pairs of non-arcing contactsand a Vpair of arcing contacts, and means comprising a rotary cam having cam surfaces foreffecting a closure of said pair of arcing contacts and different pairs of said non-arcing contacts when said cam is rotated to a plurality of switch closing positions to effect a different multi-pole switching function` in each switch closing position, said cam surfaces being arranged so that when said cam is rotated away from any one of said switch closing positions said arcing contacts are opened prior to said non-arcing contacts whereby arcing occurs only at said arcing contacts.

3. A multi-position )multi-pole switch comprising an insulating supporting panel, a plurality of pairs of relatively movable normally open contacts mounted on said panel, said pairs of contacts including at least one pair of non-Y arcing contacts and at least one pair of arcing contacts, means comprising a single movably mounted cam member for vclosing all of said pairs of contacts, said cam member having at,

1 closed subsequent to the non-arcing contacts and upon a movement of said cam from said switch closing position said arcing contacts are opened prior to said non-arcing contacts whereby arcing occurs only at said arcing contacts and only said arcing contactsl need be formed of arc resistant material.

4. A multi-position multi-pole switch comprising an insulating supporting panel, a plu` rality of pairs of relatively movable contacts mounted on said panel, said pairs of contacts including at least one pair of non-arcing contacts Vand at least one pair of arcing contacts, a single movably mounted cam member for actuating all of said contacts, said cam member being movable to aV switch opening position in which said pairs of contacts are open and to at least one switch closing position in which a pair of non-arcingr and a pair Vof arcing contacts are closed to effect a multi-pole switching function, said cam member being shaped so that upon a movement of Ysaid cam member to said` switch closing position the arcing contacts are closed subsequent to the non-arcing contacts whereby arcs formed upon the closing 0f said contacts are dissipated at said arcing contacts.

5. A multi-position multi-pole switch comprising an insulating supporting panel, a plurality of pairs of relatively movable contacts mounted on said panel, said pairs of contacts including at least one pair of nonarcing contacts and at least one pair of arcing contacts, a single movably mounted cam member for actuating all cf said pairs of contacts, said cam Ymember being movable to a switch opening position in which said pairs of contacts are open and to at least one switch closing position in which a pair of non-arcing and a pair of arcing contacts are closed'to eiect a multi-pole switching function, and said cam member being shaped so thatV upon a movement of said cam member from said switch closing position said arcing contacts are opened prior to said non-arcing contacts whereby arcs formed upon the opening of said contacts'are dissipated at said arcing contacts;

LESLIE' A. KENIPTON.