US2810029A

US2810029A - Snap acting drum switch

Info

Publication number: US2810029A
Application number: US562767A
Authority: US
Inventors: Hutt Philip
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1956-02-01
Filing date: 1956-02-01
Publication date: 1957-10-15
Anticipated expiration: 1974-10-15

Description

Oct. 15, 1957 P, HUTT SNAP ACTING DRUM SWITCH 2 sheets-sheet 1 Oct. 15, 1957 P. HUTT 2,810,029 l SNAP ACTING DRUM SWITCH 2 Sheets-Sheet 2 Filed Feb. l, 1956 means.

2,810,029 Patented "Oet- 15, 1957 United States Patent *,*Oftice l,SNAP ACTING .DRUM `SWITCH Philip Hutt, Milford, Conn., assigner to General Electric Company, a corporation of New York Y The `present invention 'relates kto an electric switch and particularly to a reversiblesnap acting drum switch that is particularly adapted to bemounted on the standard or column .o f aportable lamp for'controlling the several circuits thereof.

The great majority of portable `lamps in use today are provided with a combined lamp socket and switch either of the turn knob or pull chain types which are hidden from view bythe lamp shade. There are also many floor lamps -where the fturn 'knob switch is separate from the lamp socket but again it is hidden by the lamp shade. In an attempt to increase the ease of operating portable lamps, switch designs have been conceived for either the base of the lampor the column of the lamp so that it will 'be out from under Athe lamp shade `and clearly in view.

The novel drum switch of the present invention i s 'believed Vto be improvement over other switch mechanisms in the prior art, gbecauseitisboth reversible in that it canbe turned either clockwise or counterclockwiseand the contacts are quick acting so that this switch is usable in b oth A. C.' and 1D. C. circuits. The basic elements o f my invention include a yfirst 'switch member ortubular base Yhaving a series o f ratchet teeth, several o f which are current carrying to comprise the iixed contacts' of the switch, and a second switch vmemberordium which is relatively rotatable with respectto the first about the vertical centerline o f .the switch, and has a similar series of ratchet teeth but inclined in the opposite direction- Most of the ratchet teeth of this second series are joined together and are current carrying to comprise the movable contact of the switch. vinterposed between the two series of ratchet teethis a third intermediate member consisting of an insulating washer supporting a series of contacting pawls which are symmetrically arranged above and below the washer for engaging the ratchet teeth ofthe two switch members. Thus,v as the second switch member is rotated in one direcfon with respect to the irst switch member, ,the top pawls of the intermediate member will become locked with respect vto the second switch member while the bottom pawls will sweep the ratchet teeth of the first switch member. Then as the second switch member is rotated in the opposite direction, Athe bottom pawls of the intermediate member will become `stationary with respect toethe ratchet teeth .of the iirst switch member and sweep the ratchet teeth of the second switch member. The series of pawls of the intermediate mem` ber serve the dual function vof connecting the movable contact with the `fixed contacts of the switch while also serving to index the movement of the switching elements. The principal ,object of this invention is to provide a drum switch Iwith a reversible snap acting mechanism'.

A Afurther object of this invention is to provide Va reversible snap actingdrum switch with a suitable ,indeinng Aifurtherobject of thisinvention is to providea rev ers 'i. ble snap acting drum switch with an intermediate member containinga series of contacting pawlswhich are pivotally mounted onan insulating washer to connect the movable `contact with theixed contacts ofthe switch.

A still further object of the present `invention is to provide a reversible snapV acting drum switch lwith two series of ratchet teeth, theiirst series containing the fixed contactsof the switch while the second series includes the movable vcontactor of the switch, all o fwhich are adapted to be joined together by an intermediate member c ontaining a series of. contacting pawls that also serve the function of an indexing means;

My invention will be better understood from the following description taken in connection with the accompanying drawings and its scope'will be pointed out in theappended claims. t

Figure 1 is an elevational view of atypical table lamp having mounted kon its column a drum switch embodying my ,inventiva Figure 2 is` an enlarged view `of the drum switch of Figure l shown separated from the lamp.

Figure 3 is an exploded view showing in detail the varions elements of my invention.

Figure 4 is a cross-sectional elevational view .of the switch of Figure 2 talen on its vertical center line.

Pignre 5 is a cross-sectional view showing the method .ef fastening the assembly Washers te -thesplit bushing for supporting the switch ina lamp. f Y

, Figure .61s ,detailed Showing ef befhlhe neieh ,itl .the edge of theinsnlating washer ofthe in termediate`inember and the contacting pawl which is to be supported therein.

Figure 7 is an assembled View showing the contacting pawll of Figure `6 supported in the notch of the insulating washer.

Figure 8 is a diagrammatic showing of thefol positionto'r the switch `with the two series o'f ratchet teeth conaining the xed and movable contacts of Athe switch as they are bridged by the contacting ,pawls of vthe intermedi.- atte' membe'r. i

1Figure 9 has additional diagrammatic showings ofthe different positions ofthe switch when lthe top member .orldrurn is rotated in a clockwise direction or to the left through the low, medium and -high positions of the switch.

Eignre 1 0 is a diagrammatic showing Aof Ythe wiring arrangement of a portable llamp including a three-way lamp socket and andrum switch embodying my-invention.

Figure l-l is a bottom plan view of `the rotating'drum of thes'witch showing the single movable Vcontactassernbled therein with relation'to the pair of molded ratchet teeth ofthis member. Figure 12 is -a -top plan view of the tubular base of therswitch showing the angular disposition of Vthe :fixed con'acts of the switch with respect to the other vratchet teet Referring :in detail to the drawing, Figure 1 shows a table :lamp 10 including a supporting base 11, a colnmn 1 2` and a decorative husk -13 for containing the vscrew shell socket of `the lamp. The lamp shade 1.4vis usually translucent which `makes it difficult to find `tliensnal turn knob or push `through switch if `it is combined with the lamp socket. VMy invention is embodiedV in the drum switch 15 assembled in the column 1 2 o f `the -lampfor controlling fthe lighting circuits of the lamp.

Turning now to `a consideration of the specific details of `the switch in Figure 3, the supporting Amember of the switch elements is a split metal ybushing 20 which is internally threaded at both ends `so that the switch may be fastened tothe conventional wiring pipesor conduits (not shown) of theglam'p. Thesepipesareghidden from sight `by the two pieces of deeerativeztubing 16 `.and

i 17 that are assembled between the switch and the lamp v,2,810,029 t Y base 11 and between the switch and the husk 13, respectively. A longitudinal split 21 is provided so that the bushing may be temporarily collapsed to reduce its diameter and a pair of assembly washers 22 slipped over the ends. The outer surface of the bushing has two rings of radially spaced projections or embossings 23 which are arranged in pairs to form clamping lips at both ends of the bushing for engaging the washers 22. Looking for a moment will be understood that when the diameter of the bushing is reduced, each washer 22 may be forced over the end of the bushing until it is confined in the ring between the pairs of embossings 23 and held firmly in place. While the method of mounting the drum switch of this invention is being described in detail herein, it is deemed to be a separate invention from that of the switch mech- Vanism; therefore, it is being claimed in my copending application Serial No. 562,799 filed simultaneously with this application and assigned to the same assignee asis the present invention. Y v

Looking at Figure 3, the present switch comprises two main switch members, namely, the tubular base 25`which 'is mounted on the bushing 20, and the drum 26 that is at Figure 5 of the drawing, it v telescopically arranged over the base to enclose the switching elements. In the preferred form of my invention both the base and the drum are molded of a suitable insulating material such as melamine, urea, or the like. Base 25 includes a series of upwardly facing ratchet teeth 27 arranged at the foot of the hub portion 28. The inner f surface of the top of the drum 26 has a similar series of ratchet teeth formed by the split brass ring 29 having teeth 30 which are Vopposed to the ratchet teeth 27 of the base by being inclined in the opposite direction. The

ring 29 is mounted within the drum so that the split vportion is separated by a single ratchet tooth 31 that iS a molded portion of the drum as seen in Figures 8 and ll for continuing the configuration of the ratchet teeth around the entire inner surface of the drum. The side of the ring 29 which is opposite the split is undercut as at 32 in Figures 3 and 8 so that a single molded ratchet tooth 33 similar in shape to the tooth 31 replaces the usual ratchet tooth of the ring 29. The insulated

ratchet teeth

31 and 33 of the drurn provide the two off posi- Ations of the switch, while the single split ring 29 contains two groups of ratchet teeth 30, there being three teeth in each group providing the 1ow, medium and high` positions of the switch.

Going back to a consideration of the ratchet teeth 27 of the base '25, as seen in Figure 3, several of the teeth are replaced by contacting elements 34 which when mounted in the base represent the fixed contacts of the switch. Lead wires 35 are crimped or otherwise fastened (to the contacts for connecting them in the lamp circuit. As best seen in Figure 4, the lower interior of the base 25 is cut away as att36 so that the'contacts 34 with the lead wires 35 attached may be inserted therein with each contact being held in place in a narrow opening 37 that extends outwardly of the base. Each contact 34 is assembled in the base by bending or staking the side edges of the contact inwardly toward the central axis of the base so that the contact may not be withdrawn by a pull exerted on the lead wire 35. The means for securing the lead wire 35 on the shank end of the contact prevents it from moving up out` of the base, so that the con- 'tact is rigidly fastened inthe base. There are in effect eight ratchet teeth in the drum, namely, the six teeth 30 of the movable contact 29 andthe moldedteeth 31 and 33, so that in a similar manner there would be eight ratchet teeth in the base. However, there are three fixed contacts 34 mounted in the base so that between two of the contacts there is but a single molded ratchet tooth while there are two such molded teeth separating the third contact from the first two mentioned contacts.

' As discussed previously, the tubular base 25 is to be fixed on the bushing 20. This is done by` supporting the 4 base on the lower washer 22 from turning with respect to group of three longitudinally the interior of the circular opening 39 that extends through the base. There is a sliding fit between the opening 39 of the base and the bushing 20 and the embossments 23 of the bushing are seated within the grooves 38 in the base to prevent the relative rotation of these parts.

One of the most important elements of this invention is the intermediate member 40, now to be discussed, that is interposed between the two series of ratchet teeth on the base and on the drum for connecting the movable contact 29 with the fixed contacts 34. The use of this intermediate member provides this switch with a reversible snap action, as well as a uniform indexing means in all positions of the switch. The intermediate member 40 is constructed out of a thin insulating washer 41 of fiber material that is adapted to slip over the hub 28 of the base 25. As best seen in Figures 6 and 7, the peripheral edge of the washer 41 has a series of notches 42 formed therein with a restricted opening 43 at the very edge communicating with the larger portion which is generally of rectangular shape. A contacting pawl 44 of thin, spring strip material such as phosphor bronze is adapted to be supported by a quick slip-on assembly and preventing the base the bushing by forming a extneding grooves 38 on vmethod in the notch 42 of the washer so that the washer tion 47 are spaced apartrby a distance substantially equal to the thickness of the washer 41 to provide a close sliding fit between these parts. The inner edge of the base 48 of the U-shaped portion 47 has a spring locking tongue 49 that is bent back upon itself for holding the pawl 44 on the washer. Looking now at Figure 7, it will be understood that the pawl 44 is in its assembled position on the washer 41 and the locking tongue 49 is seated behind one of the lips 50 which serve to form the restricted opening 43 in the edge of the washer. Although only one lip 50 is needed to lock the pawl 44 in the washer, the notch 42 is made symmetrical so that the washer is identical on both sides and the operator 'in assembling the switch need not spend time determining the correct side of the washer. Y The pawl 44 is capable of a slight pivotal action with respect to the washer 41 since the supporting portion 47 of the pawl may slide back and forth on the washer lin a radial direction when the locking tongue 49 is compressed slightly. The advantage of this freedom of action is that the pawls 44 will adjust themselves to the space between the molded base and drum. The contacting pawls 44 could, of course, be riveted or otherwise rigidly fastened to the Washer but this would require a high degree of accuracy in forming and positioning these parts to prevent binding or interference between the pawls 44 and the molded base or drum. Also, riveting would be a more expensive method than the slip-on assembly previously mentioned. i

Now that all ofthe structural details of this switch V have been described, attention will be given to the nature intermediate member 40 is shown. as-arranged between the base and the cover and is represented by the insulating washer 41 and the series of contacting pawls 44.

Figure l is a wiring diagram showing'the drum switch I embodying my invention connected inl a circuit for controlling a three-way lamp socket 53. The power supply cord includes the attachment plug 54 and

conductors

55 and 56. One side of the line, conductor 55, is `connected with the center fixed contact 34 designated Line in Figure 8, while the other conductor 56 extends completely through the switch 15 and is connected with the screw shell (not shown) of the socket 53. A three-way socket is of well-known construction in this art and is for use with a two filament lamp that is capable of giving `three degrees of illumination. Each filament is of dififerent size to give varying degrees of light so that the :smallest lilament gives one degreeof light, thezlarger filament givesanother degree and then the combination of the two give a third degree of light. Such a three-way socket contains two Vcenter contacts (not shown) which ,are connected by means of conductors 57 `and 58 to the two outer fixed contacts 34 in the base designated 1 and 2.

Thus, the circuit is complete, but as the switch is shown in Figure 8, it is in the olf position since the 'circuit is broken by the contacting pawl 44 engaging lthe central ixed contact 34 designated Line which is also engaging the molded insulating ratchet tooth 33 of the drum. lIf in Aplan view the drum were rotated clockwise, it would in Figures 8` and 9 move from right to left. This is actually what is shown in Figure 9 wherepthere are three diagrammatic views of the switch positions low, medium and high At the top of the figure the movable contact'ig has moved one notch Ato the left so that the circuit is complete from the line to the central fixed contact 34 through one of the contacting pawls 44 to the movable contact 29 and Vback through another contacting pawl -44 to the left-hand iixed contact 34 and `then through the socket, `the lamp, and then backthrough the screw shell to the source of energy. It will be noted Vthat the insulating ratchet tooth 31 of the drum 26 is aligned `with the right-hand ixed contact 34 so that only a single fila ment of the lamp bulb would be energized. In themiddle diag-ram of Figure `9 the movable contact 29 has moved another notch to the left so that the circuit extends from the central fixed contact 34 through to the movable contact 29 and then back to the right-hand fixed contact 34. Likewise, in the 'bottom diagram of Figure 9, the movable Contact 29 has moved a further notch to the left confiecting all of the fixed contacts in the circuit to give .the maximum illumination of the lamp bulb. t n

Going back again to Figure 8 for a consideration Y.of the action of theV intermediate member 40, it should be noted Vthat the arms 45 of the contacting pawl 44 extend outwardly inthe same direction, namely to the right, in asymmetrical manner with respect to the washer 41. Thus, as the drum is rotated clockwise inplan view,.it will move to the left in VFigure 8, but since the free end ofthe upper arms 45 of the pawl 44 engage the vertical risers of theratchet teeth of the drum, the intermediate member will be carried along with it. However, since the base y25 is rigid with respect to the bushing 20 and thus the entire lamp 10, it should be understood that the lower arms 45 of the contacting pawl 44 will sweep the ratchet teeth 27 'as well as Vthe fixed contacts 34 of the base. This is true .because the ratchet teeth of the base are opposed to the complementary ratchet teeth of the drum so that as .the intermediate member 40 moves to the left or clockwise,'the lower arms 45 of the contacting pawl 44 merely slide over the inclined surfaces of the ratchet teeth and doLnotengage the vertical risers thereof.

4In considering the action of the switch when the drum is lturned in the oppostie direction, lnamely counterclockwise, it will be understood that the relationship between the ratchet teeth .of :the drum and the 'intermediate memlier has been reversed. The intermediate member 40 can noflonger move with the drum which would in Figure 8 kbe 'from left to .right since the lower arms 45 Aof the pawls engage the vertical risers of the Vratchet teeth '27 and of the base 25. Hence, the intermediate member is stationary with respect to the base 25 while the upper arms 45 of the contacting pawl 44 are swept by the ratchettee'th 31 and 33 of the drum as well as ratchet teeth 30,0f the single movablecontact 29. Since the intermediate `meinber 40 is freely oating in` thatit may shift vertically on the hub 28 of the base 25, itis an interestingphenomenon that the arms 45 of the contacting pawl 44 are deected by substantially equal amounts whenever the drum is rotated. Thus, when there is a compressive -force tending to deiiect the arms` on one side of the linsulating washer 41, that force is likewise carried into the vcomplementary portions of the contacting .pawls so Vas to reduce the maximum stress` exerted on any portion :of 'the pawls. As `a result, all ofthe pawls arestressed simultaneously to ugive both a uniform switching action and long lifeto the c ontacting parts. The contacts are also vkept clean from oxidation yand dirt formations that might collect due to Y the wipingaction afforded by the pawls of the `intermediate member.- i

Having described my invention of a rotating drum switch that :is capableof lbeing mounted on the column of a portable lamp, it will bc well understood by those skilled in this `art that this switch is reversible in that ythe outer drum or `actuating member may be turned veither clockwise or countercloclwise. Ivf the lamp is to be used mostly at thehighest degree of illumination the switch can be turned onernotch from `pff to high` rather than going in the reverse direction through low and rnedium t0 highf" 4 Y v v Furthermore, this switch has vquick make 'andbreak contacts because-of the use of the snap-acting spring pawls which cooperate with the two series 'of ratchet teeth in the base and drum. `Since all of the pawls `are stressed simultaneously, they give the switch an excellent rsmooth and uniform feel during the changing `of the position of the switch. While I have chosen to use eight ratchet Yteeth in both the base and drum, it is recognized that other groupings which are multiples of four may also be selected. Eight teeth were'chosen in the preferred embodiment because of the particular angle of inclination of the ratchet teeth which Aresulted. Although this angle is not critical, it should be `large enough to provide a positive indexing force tending to hold the drum in a predetermined location for each position of the switch. This means that the drummay notbe turned sothatthe pawls engagefand are hung on the very tips of the ratchet teeth of either the base orA the drum. The forces stored `in the spring pawls 44 tend to return the drum `to the position shown in Figure `8 when the hand `is removed from the drum.` x

Those skilled in this art will immediatelyrecognize that my invention deals with the particular `combination yof two series of ratchet teeth containing the movableand fixed contacts respectively which `are joined by `an inter.- mediate member that supports a group of spring pawls. My preferred embodiment placesthese Velements .in a stacked relationship of base, intermediate member and drum reading from bottom to top. However, I appreciate these same `elements could be `combined -in concen- -tric ring fashion with the opposed `ratchet teeth either such as the top with the intermediate member covered thereover and again bridging the movable and fixed contacts. Likewise, the parts could `be `reversed by forming the intermediate member with ratchet teeth `.while Athe movable and fixed contacts comprise spring pawls `to give a similar switching action.

Other wiring arrangements of my switch yin a pQrtable lamp will, of course, beevident depending on whetherqthe switch fis to be wired directly to lthe' lamp socket .or fto ,a junction block that may either be in the supporting base operation that recommend 7 of the lamp or near the socket. The present drum switch has many desirable features as to cost, appearance, and i its use in portable lamps but it could also be adapted for small fans and appliances as 'well as wall mounted house switches for controlling Vthe lighting circuits.

Itis important to note that while I have chosen to illustrate my invention with edgewise contacts, an alternate construction would include atwise contacts seated on the inclined surfaces of the ratchet teeth.

Modifications of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications which are Withn'; the true spirit and scope of this invention.

What I claim as new and Patent of the United States is:

1. A reversible snap acting rotary switch comprising a first switch member with a series of ratchet teeth, some ofwhich arecurrent-carrying and constitute the fixed contacts of the switch, a second switch member also hav- 'ing a series of ratchet teeth, some of the second series of ratchet teeth being current-carrying and joined together to form the movable contact of the switch, and a third member of insulating material positioned in operative relation with said first two members and supporting a plurality of spring contacting pawls of conductive material for wiping engagement with the two series of ratchet teeth so that upon rotation in one direction of the second switch member, the third member will become stationary with respect to the first switch member while the pawls will sweep the teeth of the second switch member, and upon rotation of the second switch member in the opposite direction, the third member will be driven in the reverse manner. p

2. A reversible snap acting drum switch comprising a base member with a series of ratchet teeth, some of which are current-carrying, a drum member also having a series of ratchet teeth, `some of which are currentcarrying and joined together to form the movable contact of the switch, and an intermediate member of insulating material supporting a plurality of spring contacting pawls of conductive material for wiping engagement with the two series of ratchet teeth so that upon turning the drum in one direction, the intermediate member will become stationary with respect to the drum while the pawls will sweep the ratchet teeth of the base member, and upon turning the drum in the opposite direction, the intermediate member will become stationary with respect to the base while the pawls will be swept by the ratchet teeth of the drum.

3. A reversible snap acting rotary switch comprising a first stationary switch member with a series of ratchet teeth, some of which are current-carrying and constitute the fixed contacts of the switch, a second switch member also having a series of ratchet teeth but opposed to th-e teeth of the rst series, most of the ratchet teeth in the second series being current-carrying and joined together to form the movable contact of the switch, and a third intermediate member of insulating material supporting a plurality of spring contacting pawls of conductive material, each of which extend on opposite sides thereof for wiping engagement with the two series of ratchet teeth, so that upon rotation of the second switch member in one direction, the intermediate member will become stationary with respect to the second switch member while the pawls will sweep the teeth of the first switch member and upon rotation of the second switch member in the opposite direction, the intermediate member will operate in the reverse manner.

4. A reversible snap acting rotary switch comprising a tubular base of insulating material with a cylindrical hub and a series of ratchet teeth circumferentially arranged around the hub at one end thereof, several fixed desire to secure by Letters electrical contacts representing some of the alternate ratchet teeth, and an insulating washer mounted on the hub supporting a plurality of individual V-shaped spring pawls each supported at their centers on the washer, and a rotating drum of insulating material telescopically arranged over the hub to enclose the electrical switching elements, the inner surface of the top of the drum having a series of ratchet teeth most of which are joined together to be current-carrying and representing the movable contact of the switch, whereupon rotation of the drum in one direction will rotate the insulating washer so that the pawls will sweep the ratchet teeth of the base, and upon rotation of the drum in the opposite direction, the washer will be held stationary with respect to the base and the ratchet teeth of the drum will sweep the spring pawls.

5. A reversible snap acting rotary switch comprising a rst switch member of insulating material having a series of ratchet teeth arranged in a circular manner, several of the alternate teeth being of conductive material and representing the fixed contacts of the switch, a second switch member of insulating material having a similar series of ratchet teeth but extending in the opposite direction, most of the ratchet teeth of the second series being of conductive material and joined together to represent the movable contact of the switch, and an intermediate insulating member freely iloating between the two switch members and supporting a plurality of spring pawls which are adapted to complete the circuit between the movable and fixed contacts in such a manner that upon rotation of one of said members in one direction, the intermediate member will be driven by the moving member so that the pawls will sweep the ratchet teeth of the other member, and when the movable member is rotated in the opposite direction, a reverse operation will take'place.

6. A reversible snap acting rotary switch comprising a first switch member of insulating material having a series of ratchet teeth arranged in a circular manner on one face thereof, several of these teeth being formed of conducting material and representing the fixed contacts of the switch, and a second switch member of insulating material supporting a split metal ring having a similar series of ratchet teeth but inclined in the opposite direction from the first series, said second member being telescopically arranged over the iirst switch member to rotate about a common vertical axis, and a freely rotatable intermediate contacting member including an insulating support piece carrying a plurality of V-shaped spring contacting pawls which are insulated from each other to connect the ratchet teeth of the movable contact with the fixed contacts of the first switch member, so that upon the relative rotation of the second switch member in one direction, the pawls of the intermediate contact member will become stationary with respect to the moving member while they will sweep the Contact of the other switch member, and the reverse would be true upon the rotation of the movable switch member in the opposite direction.

7. A reversible snap acting drum switch having a base member with a circular ratchet surface, some of the alternate teeth of which are of conducting material to serve as the fixed contacts of the switch, a drum supporting a single contact member having a series of ratchet teeth which are opposed to the rst series of ratchet teeth, said drum being relatively rotatable with respect to the base so that the single contact member represents the movable contact of the switch, and an intermediate rotatable member of insulating material supporting a series of V- shaped spring contacts comprising pawls for connecting the movable with the xed contacts while also serving as an indexing means so that the rotation of the drum in one direction will drive the intermediate member with the pawls of the intermediate member sweeping the ratchet teeth of the base, while if the drum were to be rotated in the opposite direction, the intermediate member would become stationary with respect to the base and the pawls of the intermediate member would be swept by the ratchet teeth of the movable contact.

8. A reversible snap acting drum switch comprising a tubular bushing having supported thereon a stationary base member of insulating material with a continuous ratchet surface, several of the teeth of which are of conducting material and represent the fixed contacts of the switch, and a hollow drum of insulating material telescopically arranged on the said bushing to overlie the base member, a single metal contact member having a series of ratchet teeth supported within the drum in opposed relation to the iirst series of ratchet teeth on the base, said contact member constituting the movable contacter of the switch, and a rotatable intermediate contacting member comprising an insulating washer supporting a series of V-shaped contacts which'arel symmetrically arranged on the top and bottom of the washer to connect the movable and the fixed contacts for controlling different circuits through the switch.

9. As an article of manufacture an intermediate contact member for an electric switch comprising an insulat 10 ing washer having a series of notches formed in the outer peripheral edge thereof, and a V-shaped spring contact having a locking tongue at its apex which is mounted in the notch with the tongue bearing against the opposite side of the notch in cooperation with an inwardly facing lip formed at the mouth of the notch whereby the spring contact is pivotally supported on the washer.

10. As an article of manufacture an intermediate contact member for an electric switch comprising an insulating washer having a series of notches, each formed in the edge thereof for supporting a V-shaped spring pawl that is symmetrically arranged with respect Vto the washer, and a spring locking tongue extending from the apex of each pawl and engageable with an opposing wall of the notch.

References Cited in the le of this patent UNITED STATES PATENTSV 1,138,763 Klein May 11, 1915 2,136,369 Belcher July 9, 1937 2,163,864 Bissen oct. 12, 1931