US2978549A - Rotary switch - Google Patents

Description

April 4, 1961 H. H. KRUEGER 2,978,549

ROTARY SWITCH Filed Feb. 28, 1958 2 Sheets-Sheet l IN V EN TOR.

LD CU n HowMo -LKnuaen A'rva A Ev April 4 1961 H. H. KRUEGER 2,978,549

ROTARY SWITCH Filed Feb. 28, 1958 2 Sheets-Sheet 2 INVENTOR. HowAn o H. Knuzasn Unted States Patent O ROTARY SWITCH Howard H.` Krueger, Milwaukee,

Hammer, Inc., Milwaukee, ware Wis., assigner to Cutler- Wis., a corporation of Dela- This invention relates generally to electrical switches particularly to multi-position rotary switches for controlling a plurality of electrical circuits.

The object of this invention is to provide a low-cost, compact, completely enclosed rotary switch for controlling a plurality of circuits.

The switch is constructed from a minimum number of easily assembled parts manufactured by relatively inexpensive starnping dies and requiring no molded parts. It consists of a flat insulating base plate having a plurality of punched openings therein. A plurality of stationary contacts and single common contact having a corrugated contact surface are mounted in such openings. An actuating shaft is rotatably mounted in the base and serves as a pilot for assembly of a movable contact member, a rotor for driving the movable contact, a spring and a cupshaped housing in that order. The housing is fastened to the base to enclose the parts and compress the spring to urge the rotor and movable contact toward the contacts mounted in the base. The movable contact member has an indexing portion adapted to move between the corrugations in the common contact as the actuating shaft is rotated to provide the feel of the switch, and a selector portion adapted to move in and out of contact with said stationary contacts as the shaft is rotated to thereby control a plurality of circuits.

Other objects and advantages will be pointed out in, or be apparent from the specilication and claims, as will obvious modifications of the single embodiment vshown in the drawings, in which:

Fig. l is a bottom plan view of a switch embodying the invention;

Fig. 2 is a vetrical sectional view taken along line 2-2 of Fig. l; j

Fig. 3 is a horizontal sectional View taken along broken line 3-3 of Fig. 2; f

Fig. 4 is a horizontal sectional view taken alone line 4--4 of Fig. l2 with parts of the rotor broken' away;

Fig. 5 is a side elevation view of the combination rindexing and common contact plate; Y

Fig. 6 is a fragmentary sectional View of the switch base taken along line 6 6 of Fig. 3; and

Fig. 7 is a fragmentary sectional view of the switch rotor takenalong line '7*-7 of Fig. 4.

Referring tothe drawings, Fig. l shows an insulating base plate 10 of phenolic or other suitable insulating material havingfaces 11 and 12 and holes13 punched out or otherwise formed therein' for receiving spade-typeV terminals 14 andanc'horing lugs A15 extending from'contact portions '16 of stationary contacts 18 and'punched-out holes 20 and 22 for respectively receiving'terminal '124' (likewise shown `as of the spage-typajsee Fig. 5), and auf choring lugs 26:'exten`ding frogth'e contact portion 28 of acombin'ation' indexing andV common contact"30. The

the contact ,portions 16 of the stationary contacts (see Fig. l) to seal the openingsandretain ,the'contacts when terminals 14 and lugs thereof arestaked to face 12 of the base plate 10, as shown. Similarly, the terminal 24 and lugs 26 of common contact 30 are staked to face 12 of the base (Fig. 1) to securely tix said contact 30 to the base. Said three contacts 18 and contact 30, preferably of half hard brass, may be made from any suitable conductive material. While the contacts of the disclosed embodiment have spade-type terminals, it should be understood that contacts with other types of terminals such as solder-lug terminals, etc. may be provided therefor.

The relatively large punched holes in base 10 permit the use of punching dies of relatively large cross sectional dimensions, which lowers die maintenance and thereby reduces cost.

A reduced cylindrical end portion 32 (Figs. 2 and 3) of a square actuating shaft 34 is inserted through a central circular opening 36 in base 10 and then riveted over to form a retaining shoulder 38 (Figs. 1 and 2). The space 40 (Fig. 2) between retaining shoulder 38 and shoulder 42 on shaft 34 is slightly greater than the thickness of base 10 to insure a freely rotating shaft. This construction eliminates the need for a retaining washer on the end of shaft 34 to thereby reduce cost.

The remaining parts including an electrical insulating libre spacer 44, a contact ring 45 (preferably of half hard copper), an insulating rotor 46 (preferably of phenolic resin), and a coil spring 48 are then placed on shaft 34 (which serves as a pilot) in that order followed by a stamped metal switch frame or housing member 50 and threaded bushing 52 fastened to base 10 by tabs 54 seated in notches 55 in spacer 44 and base 10 and clinched over the bottom of the base. Finally, a knob 56, preferably of molded insulating material, may be installed on the split end of shaft 34, preferably of rectangular form in cross section, to complete the very simple and easy assembly of the switch.

Switching is accomplished between common contact 30 (see Figs. 3 and 5) and the three stationary contacts 18 by contact ring 45 (Figs. 2 and 4) rotated by rotor 46 (Figs. 2 and 7) by means of tabs 60 on the ring 45 seated in notches 62 in the rotor (Figsf7) and held firmly between rotor 46 and spacer 44 by the force of spring 48. As shown in Fig. 4, rotor 46 is rotated by square shaft 34 extending through rectangular opening 64 therein between the limits (somewhat less than degrees) defined by diametricallyv opposed abutments 66 on the rotor periphery and the integral inwardly projecting rib 68 formed in the side of switch frame 50. A clearance 69 is provided between shaft 34 and opening 64 (Figs. 2 and 4) to permit tilting of the rotor on the shaft as explained more fully hereinafter. V

Contact is made between ring 45 and contact portions 16 and 28 of the stationary and common contacts, re-

spectively, by. diametrically opposed indexing and selector corrugations 70 and 72 in ring 45 which wipe against the surface of the contact portions exposed by suitable openings 73 and 75 in spacer 44 (Fig. 3). As shown in Figs. 3 and 5, contact portion 28 of common contact 30 is a corrugated ring segment having flat end portions 74 and 76 and valleys or grooves 78 and 80 in the corrugated portionof the segment intermediate the two flat `end portions. v 1 Y l The switch operates by rotating shaft 34 to cause inrdexing corrugations V70 in ring 45 to move in'sliding contact with common contact whileseiector corrugation 72 moves intol and ont 't contact with three stationary contacts 18 to thereby complete electricalcircuits `between the common contact and eachof thevstationary contacts.

andthen allow' ring 4S to 'be' 4snapped into the next cor- Y `2; asv/itch' awarding t0 slain rugation as the switch is moved from one position to another. Fig. 4 shows the switch in the OFF position with selector corrugation 72 contacting spacer 44 and out of contact with any of the three contacts 18. Clockwise rotation of shaft 34 (as viewed in Fig. 4) will cause ring 45 and rotor 46 tobe tilted upwardly and then snapped downwardly a-s indexing corrugation 70 moves 45 degrees from flat end portion 76 upwardly over a peak '79 and then downwardly into a groove 80 of common contact 30. At the same time corrugation 72 on the ring has moved from spacer 44 intocontactwith the left-hand contact 1S (as viewed in Fig. 4) with a snap action to electrically connect the two contacts. Continued clockwise rotation will move corrugation 70 up over a peak 81 into a groove 78 and then lover a peak 83 on to at end portion 74 of common contact 30 while corrugation 72 moves on spacer 44V from the left-hand to the middle and then to the righthand stationary Contact 1-8 of Figs. 3 and 4. Further clockwise rotation is prevented bythe aforementioned rib 68 in the housing. Contact arcing will cause carbonization or tracking between contacts on the surface of some insulating materials such as phenolic. To prevent this, spacer sheet 44 is providedwhich, because it is made from electrical insulating fibre, will not be affected to any substantial extent by arcing at the contacts.

The tilting action of ring 45, permitted by clearance 69 (Figs. 2 and 4) between the shaft and the rotor, will cause a slight sliding action of indexing and selector corrugations 70 and 72 on the contacts along a diameter line between the ridges of the two corrugations to thereby provide a wiping action at the contact surfaces in addition to that provided by the angular movement of the corrugations on the contacts.

The single embodiment shown in the drawings and described above has 45 degree indexing and three stationary contacts 18 for controlling three separate circuits. It should be understood, however, that various changes and modifications such as variations in the degree of indexing and number of circuits can be made without departing from the spirit of the invention or lfrom the scope of the appended claims.

1. A switch comprising an `insulating base having a plurality of openings therein spaced in a circle, a plurality of `stationary contacts and a common contact plate mounted in said openings Vand having contact surfaces substantially iush with one face of said base and terminal portions extending through said openings to the other surface of said base, an actuating shaft rotatably mounted in said base, an insulating rotor tiltably mounted on said shaft opposite said one face of `said base and rotatable with' said shaft, a contact member having an indexing portion and a selector portion mounted between said one face' of said base and one face of said rotor'` Vand engageable by said rotor Yfor rotation therewith, a

coil spring mounted on said shaft opposite the other face of said rotor, a cup-shaped housing member mounted on said shaft having depending walls fastened to said base to thereby enclose said rotor, contact member and spring and to compress said spring between the rotor and the housing member to urge said contact member toward said one face ofsaid base, said contact surface of said cominsulating bre having a plurality of openings therein is mounted on said one face of said base with the contact surfaces of said common contact plate and stationary con tacts exposed through said openings in said sheet to minimize arc tracking between the stationary contacts caused by arcing.

3. A switch according to claim l in which the angular movement of said contact member driven by said rotor is limited by an abutment on the rotor periphery and a stop on the depending wall of said housing member.

4. A switch according to claim 1 in which said actuating shaft extends through a central opening in said base and is axially restrained therein by a pair of spaced shoulders on said shaft, with the space between shoulders mon contact having a corrugated surface `thereon forming n angularly spaced valleys and peaks, said indexing portion of said contact member adapted to move in contact with said corrugated surface over said peaks and into saidvalleys as said actuating shaft isrotated from one position to'.

another to provide the feel of the switch and said. selector portionof said contactmemberadaptedto move into contact withvsaid contact.' surface ofv one of said stationarycontacts-.with a snapaction as said indexingportion isl snapped linto onenof said valleys in said corrugated sur-'i l face by thebias of saidcoil spring as said movablecon#Y tact yis rotatedfr'omgone position to another( 1 in whichashergr -said common contact plate having nient "of Q said slightly greater than the thickness of the base to insure a freely rotating shaft.

5. A switch according to claim l in which said actuating shaft has a rectangular cross section and extends through a rectangular opening in said rotor, said opening being of suflicient size to provide a clearance space between said rotor and said shaft to allow the rotor to tilt slightly on the shaft as the switch is'actuated from one position to another to produce a slight radial movement of said selector and indexing portions and thereby provide a wiping action at the contact surfaces in addition to that provided by the angular movement of said contact member.

6. A switch comprising an insulating base, a plurality of spaced stationary contacts mounted on said base, a common contact plate mounted on said base spaced from said stationary contacts, said common contact plate and stationary contacts spaced in a circle on said base,

' a corrugated surface thereon forming angularly spaced valleys and peaks, a movable contact member rotatably mounted on said base and having an indexing portion andv a selector portion, spring means urging said movable contact member toward said base, said indexing portion of said movable contact member adapted to move in contact with said corrugated surface on said common contact plate over said peaks and into said valleysas said contact member is actuated from one position to another, said selector portion of said movable contact member adapted to move into contact with one of said spaced stationary contacts with a `snap action as said indexing portion is snapped into one of said valleys in said corrugated surface by the bias of said spring means as said movable contact is rotated from one position to another.

7. A switch according to claim 6 in which said insulating base has a plurality of'punched holes therein in which said stationary contacts are mounted, said stationary contacts having a at contact portion substantially ilus-h with' p one face of said base and a terminal lug and an anchoring` lugextending through said openings from said liat contact contacts to said base.

8. A switch accordingV to claim 6in whichsaid movable contact member is mounted on said base by means of an actuating shaft and a rotor mounted on said shaft in driving engagement with said Contact member, said actuating shaft having a portion with a rectangular cross-section extending through a rectangular Vopening in said rotor, said opening being-of suiicient size to provide a clearance space4 betweenjsaid rotor and said shaft to'allow said1 rotor toxtilton said shaft-.as the 'switch' is actuated from one position to another toiproduce aislightradial move` n Aselector and indexing'1 portions andthereby Y, tact member.

i .2(Refereneesfon :following page) provide @wiping action atgthe Contact' surfaces in addition References Cited in the le of this patent UNITED STATES PATENTS Weller Feb. 3, 1891 Rice Ian. 12, 1892 5 Despard May 8, 1928 Douglas May 16, 1933 Cobb Dec. 2, 1952 Dietrich June 30, 1953 Brown et a1 June 19, 1956 Johnson Aug. 13, 1957 FOREIGN PATENTS Great Britain Dec. 1, 1936

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