US3214536A

US3214536A - Selector switch contact construction with deformable contact support plate means

Info

Publication number: US3214536A
Application number: US180628A
Authority: US
Inventors: Henry W Wallace
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1962-03-19
Filing date: 1962-03-19
Publication date: 1965-10-26
Anticipated expiration: 1982-10-26

Description

1965 H. w. WALLACE 214,536 SELECTOR SWITCH CONTACT CONSTRUCTION WITH DEFORMABLE CONTACT SUPPORT PLATE MEANS 4 Sheets-Sheet 1 Filed March 19, 1962 [)7 ver/ 25 0)":

Hang W W //ace W16 4% /7 /LS A'ornqg 4 Sheets-Sheet 2 ATE MEANS H. w. WALLACE SELECTOR SWITCH CONTACT CONSTRUCTION WITH DEFORMABLE CONTACT SUPPORT PL 1962 Oct. 26, 1965 Filed March 1.9,

Oct. 26, 1965 H. w. WALLACE 3,214,536 SELECTOR SWITCH CONTACT CONSTRUCTION WITH DEFORMABLE CONTACT SUPPORT PLATE MEANS Filed March l9; 1962 4 Sheets-Sheet 3 umw [)7 1/6276 0/": Hang IM h/aflace,

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1965 H. w. WALLACE 3,214,536

SELECTOR SWITCH CONTACT CONSTRUCTION WITH DEFORMABLE CONTACT SUPPORT PLATE MEANS Filed March 19, 1962 4 Sheets-Sheet 4 him 4 4 [)7 van t 02":

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HAS A236 2" qg United States Patent "ice SELECTOR SWITCH CONTACT CONSTRUC- TION WITH DEFORMABLE CONTACT SUP- PORT PLATE MEANS Henry W. Wallace, Weston, Conn., assignor to General Electric Company, a corporation of New York Filed Mar. 19, 1962, Ser. No. 180,628 Claims. (Cl. 200-11) This invention relates to electrical switches and more particularly to a multiple position switch and the method of manufacturing such switch. Although not so limited, the switch is particularly useful for controlling the operation of an electrically reversible, multi-speed, shaded pole fan motor. Likewise, the method of manufacturing the switch may be employed in making many types of switches having a wide variety of applications.

In the manufacture of electric fans or similar appliances, the large volume of production frequently involved and the highly competitive nature of the business dictates that each component be as inexpensive as possible while yet providing the necessary reliability. As a means for reducing costs, it is extremely desirable that automation be employed in the manufacture of the various components. In addition to the foregoing criteria, certain components such as switches must meet various rigid safety requirements including provision to preclude shorting in the event of overheating.

Accordingly, it is the primary object of this invention to provide an improved electrical switch assembly and method of manufacturing such assembly.

It is a further object of this invention to provide a multiple position switch which may be inexpensively mass produced.

Another object of this invention is to provide an improved multiple position switch for a multi-speed shadedpole fan motor.

It is a further object of this invention to provide an energy storing switch knob which provides quick and positively acting switch operation.

Briefly stated, this invention relates to an electrical switch comprising a punched metal contact plate forming a plurality of contact elements interconnected by metallic bridges and a molded support which has projections adapted to fit within the space between the contact elements. The support is made of thermoplastic or similar material so that the projections extending through the spaces between the contact elements may be deformed under heat and pressure after the support is assembled with the contact plate. The contact elements may then be severed or separated by removal of the metallic bridges, thus leaving the contact elements in spaced, insulated relationship.

The contact plate and support assembly may be sandwiched between a case comprising a thermosetting plastic base and clamping member which are adapted to independently position the contact elements. A rotor carrying one or more contact connector units cooperates with the clamping member, and the entire assembly is securely clamped together by means of a suitable cover. To rotate the rotor, a plastic knob is provided having an integral tongue which is adapted to engage the rotor. The tongue serves as an energy storing member so that rotation of the knob provides a positive snap action. To secure the knob to the rotor, the knob may be provided with integral resilient legs adapted to cooperate with the rotor.

Further features, objects and advantages will become apparent with reference to the following drawings, in which:

FIG. 1 is a perspective view of a punched metal contact plate of the invention;

3,214,536 Patented Oct. 26, 1965 FIG. 2 is a perspective view of a molded thermoplastic support adapted to be assembled to the contact plate of FIG. 1;

FIG. 3 is a perspective view of the contact plate of FIG. 1 and the support of FIG. 2 after the components have been assembled and secured together by deformation of the thermoplastic support;

FIG. 4 is a perspective view of the assembly of FIG. 3 after a punching operation has been performed by which metallic bridges have been removed from the contact plate to form a plurality of contact elements secured to the support;

FIG. 5 is a plan, partially sectional view of the entire switch assembly of the invention;

FIG. 6 is a side elevation sectional view of the switch assembly;

FIG. 7 is an exploded perspective view showing the switch knob, cover, rotor, shading coil selector unit and selector arm unit;

FIG. 8 is an exploded perspective view of the switch clamping member, contact plate and support assembly, and base member; and

FIG. 9 is a schematic version of the switch of the invention shown connected to an electrically reversible three-speed fan motor.

The particular switch assembly shown and described herein is a rotary seven position switch, useful for example with reversible, multi-speed, electric fans to provide three speeds in each direction and an ofi position. Referring first to FIG. 6, the entire switch assembly may be seen as comprising a base 10, a support plate and contact assembly 12, a clamping and indexing member 14, a rotor 16 carrying a selector arm unit 18 and a shading coil arm unit 20, a cover 22 and a knob 24. These various components will be individually described in detail in the following paragraphs.

Describing first the support and contact assembly 12, there is shown in FIG. 1 a contact plate 26 having a pattern of apertures and forming a plurality of

contact elements

28, 30, 32, 34, 36, 38 and 40 each having a

respective terminal

28a, 30a, 32a, 34a, 36a, 38a and 40a. Contact element 36 is also provided with an additional terminal 36b. In FIG. 1, the contacts are interconnected by ten metallic bridges 42-51, which are to be removed in a subsequent operation. The contact plate with the bridges removed may be seen in FIG. 4 wherein the spaces formerly occupied by the bridges have been numbered identically with the bridges.

Since the bridges 42-51 are to be removed, it is necessary to provide means by which the respective contact elements will be permanently positioned in the desired spaced, insulated relationship. For this purpose, a support is provided having, as may be seen from FIG. 2, a pattern of projections adapted to be received within a portion of the pattern of apertures formed in contact plate 26. The support 60 is also formed with a pattern of apertures which coincide with the remaining open aperture portions of plate 26 for positioning the support and plate within the switch base 10. In accordance with the invention, the support 60 is preferably made of thermoplastic or similar material having the properties of being deformable by heat and pressure and at the same time being a good electrical insulator. As the next step of the fabrication, the contact plate 26 is assembled with the support plate 60 so that the extensions or projections on the support extend through the apertures within the contact plate. It may be noted that both contact plate 26 and the plastic support 60 are asymmetrical, so that they may be assembled only in the proper manner. Next, certain projections are deformed by heat and pressure to thereby secure the contact plate to the support, as shown in FIG. 3. It should be noted that

projections

62, 64, and four semicylindrical projections, all indicated by the numeral 65, are not deformed during the heat and pressure operation in that they serve as bearing surfaces in the operation of the switch. Also, a centrally located recess or socket 66 in the support 60 is not deformed in that it is' a bearing surface adapted to receive a portion of the rotor 16, as will be hereinafter described.

After the deforming opeartion, the bridges 42-51 are removed in a punching operation or some other suitable method, leaving the spaces 42-51 as shown in FIG. 4. By this operation, the contact plate 26 is separated into seven

different contact elements

28, 30, 32, 34, 36, 38 and 40, which are supported in insulated relationship by the support plate 60. It should be noted that portions of the thermoplastic support 60 are also removed during the bridge removing operation as exemplified at

spaces

43 and 51 in FIG. 4.

Although the contact and support assembly 12 may be produced by means of the manufacturing methods desired, one of the features of the assembly is that it easily lends itself to automation mechanism. For example, the operation may begin by passing a metal strip beneath punching equipment to punch the pattern of apertures to form the contactplate 26; and by successively repeating this operation, a strip of contact plates connected by means of their terminals may be produced. While still in strip form, a support 60 may be assembled to each contact plate, the deformation operation may be performed, and the bridges may be removed by a suitable punching operation. At this point, the contact plates are still connected by their terminals; and it should be noted that although there may be a small amount of play between the support and the contact, contact element 36 provides the necessary rigidity to the strip for further automatic procedures if desired in that both

terminals

36a and 36b would be connected to the adjacent contact plates. This continuous metal strip also prevents sheer stresses from developing between the metal and the thermoplastic. The remainder of the switches may then be assembled on the strip before the contact plates are severed from one another. Of course, the contact plate 26 may be severed from the strip prior to the subsequent forming or punching operations it a lesser degree of automation is preferred.

The support and contact assembly 12 is also shown in FIG. 8 where it is in position to be assembled to the base 10, which is provided with a plurality of upstanding projections adapted to fit within the spaces in the assembly 12. Additionally, the base 10 is provided with a central aperture 68 adapted to receive the base of socket 66-of the support 60. The base 10 also forms a major portion of the switch exterior as may be seen from the assembly drawing of FIG. 6. Again it may be noted that base 10 has its series of projections arranged asymmetrically, so that contact assembly 12 mates with the base only when assembled in a properly oriented position.

After the contact and support assembly 12 has been placed'in the base 10, the clamping member 14 is also received within the base over the assembly 12 to thereby sandwich the contact and support assembly between the two members. The clamping member 14 is provided with recesses and projections, some of which are shown at 72 and 74, adapted to mate with upstanding projections and recesses respectively of the base 10 to position the contact and support assembly. In its preferred form the base 10 and clamping member 14 are made of a heat resistant, non-conducting, thermosetting plastic, such as phenolic. With this arrangement safety standards may be easily met. In the event the switch is overheated and the thermoplastic support 60 should melt or be deformed, the contact elements will still be independently clamped in insulated relationship by the base and clamping member so that the switch will continue to function properly.

An asymmetrical design of clamping member 14 is again useful in connecting with automatic assembly techniques.

It should be noted that the clamping member 14 is provided with

openings

76 and 78 through which the depending wiper arms of the selector arm unit 18 and the shading coil arm unit 20 will extend, as shown in FIG. 6. The clamping member 14 is also provided with a central opening 79 surrounded by an upstanding annular ridge having radially extending grooves 80. The grooves 80 cooperate with the rotor 16 to provide the necessary indexing action requiredof a snap action switch as well as the phasing, as will hereinafter be described.

The remaining elements of the switch assembly may be seen in the exploded perspective view of FIG. 7. The rotor or core 16, selector arm unit 18 and shadingcoil arm unit 20 are adapted to be assembled as a unit and cooperate with the clamping member 14 and the contact and support assembly 12 to provide the contact connecting operation of the switch. The rotor 16, which is made of a thermosetting plastic or other electrically insulating material, which will remain rigid when overheated, is provided with a shaft 82 having a rounded end which, as previously mentioned, is adapted to fit through the open ing 79 in clamping member 14 and be received in socket bearing 66 of support 60.

The two

arm units

18 and 20 are made of suitable resilient electrical conducting material such as Phosphor bronze. The arm units are each provided with a central opening and are adapted to be press fitted over the rounded shaft end 82, or the units may be secured to the rotor by other suitable means. As shown, the attached end of the rotor shaft is provided with a pair of diametrically spaced flutes one of which is shown at 84. The flutes are adapted to receive the inwardly extending tongues 86 of shading coil arm unit 20. By properly selecting the dimensions of the flutes and tongues the arm unit may be self-locking on the shaft of rotor 16. The arm unit 20 is further provided with a pair of spring-like extremities 87 which are designed to snap-over the arrowlike extremity 88 on the rotor periphery to thereby lock the arm unit in position, and proper orientation is assured. As may be seen from the drawing in FIG. 7, arm unit 20 is provided with a pair of flexible, depending

wiper arms

90 and 92 which are adapted to extend through opening 76 in clamping member 14 to cooperate with the contact elements of the switch, as will be hereinafter described. When assembled, the pressure of the

contact arms

90 and 92 against the switch contact elements assists in maintaining the arm unit 20 in engagement with the rotor 16.

After the arm unit 20 has been secured to the rotor 16, the selector arm unit 18 may be pressed onto the shaft 82 of the rotor and secured thereto, in a manner similar to arm unit 20, by a pair of inwardly extending tongues 94 frictionally engaging a second pair of flutes one of which is shown at 96 on the shaft 82. A pair of

wiper arms

98 and 100 diametrically aligned with

wiper arms

90 and 92, depend from the arm unit 18 and are adapted to extend through the

openings

76 and 78, respectively, in the clamping member 14 to engage the switch contact elements, as will be hereinafter described. When the switch is assembled, the

wiper arms

98 and 100 are pressed into engagement with the contact and support assembly 12. This assists in maintaining the arm unit 18 on the shaft 82. The arm unit 18 is also provided with a pair of radially extending

corrugated sections

102 and 104 which are adapted to mate'with the radial grooves 80 in the clamping member 14. The

corrugated sections

102 and 104 and grooves 80 serve as detent means to resist rotation of the rotor. They assist also in maintaining the arm unit 18 on the shaft 82. Four wing-like extremities on the unit 18, two of which are shown at 106 and 108 cooperate with four, peripheral, step-

like features

110, 112, 114 and 116 located on the periphery of rotor 16. The flanges of the four wing-like extremities in contact with the step-like features of the rotor transmit torque between the selector arm unit and the rotor. The step-

like features

110 and 112 also result in a cut-away clearance area necessary for the flexing of the corrugated section 102 with respect to the

areas

106, 108 and that area of arm unit 18 which bears against the shaft 82 of the rotor 16. This applies also to

steplike features

114 and 116.

Once the rotor with its accompanying wiper arm units have been assembled with the clamping member 14, contact and support assembly 12 and base 10, the entire assembly should be secured together to maintain the proper relation between the respective components. For this purpose, the cover 22 having an upstanding tubular neck 132 fits over the core or rotor 16 and abuts the combined upper peripheral flange of clamping member 14 and base 10. Although it may not be completely clear from the drawings, the upper tubular neck 134 of core 16 is formed with a slight taper from a larger diameter adjacent flange 134a to a smaller diameter at the upper edge 134b, as viewed in FIGS. 6 and 7. This facilitates the molding operation. The inner surface of the neck 132 of cover 22 is formed with a cylindrical zone 132a at the base of the neck followed by a major tapered section 1321) of greater taper than the taper of core neck 134, and terminating with another cylindrical zone 1320 at the top of the neck. The resulting ring contact between core neck 134 and zones 132a and 132C of cover neck 132 provide double bearing assembly for aligning the rotating core 16 within the cover 22. The cover 22 may be secured in the assembled position by means of a pair of depending

integral tabs

118 and 120, which may be inwardly deformed into a pair of

recesses

122 and 124 formed in the outer wall of the base and deformed against the respective upper walls of the recesses, as seen in FIGS. 6 and 8. The depending cover lugs 126, 128 and 130, along with the

tabs

118 and 120, position the cover 22 with respect to the clamping member 14 and base 10, as best seen in FIG. 5.

For proper operation of the switch it is necessary to provide a means by which the rotor 16 may be rotated to the various switch positions. For this purpose, there is provided the energy storing snap-acting knob 24 preferably made of polypropylene or similar material. In accordance with the invention, as seen in FIGS. 5, 6 and 7, the knob is formed with an integral tongue or reed 136, which is adapted to be inserted through the upper opening in rotor 16 into a slot 138 within the rotor which is tapered so that the body of the plastic tongue or reed will have clearance for torsional strain while its top remains securely engaged in the bottom of the tapered slot. To secure the knob 24 to the rotor 16, the knob is provided with a pair of downwardly extending diametrically spaced

legs

140 and 142 each having an outwardly extending

nib

144 and 146 respectively. Each nib may be formed with an arcuate periphery so as to conform to the curvature of the

recesses

148 and 150 within the inner wall of the rotor. The rotational angular freedom existing between the arc extremities of the

nibs

144 and 146 and their

respective recesses

148 and 150 establishes the limits of energy storage required for providing snap action to the switch.

The dimension between the outer edges of the nibs is larger than the diameter of the opening within the rotor so that in order to assemble the knob to the rotor, the knob legs are pressed toward each other and inserted into the rotor. When the nibs are aligned with the recesses, the resiliency of the legs snaps the nibs into the respective recesses to thus secure the knob. The

recesses

148 and 150 may be provided with a peripheral dimension slightly larger than the peripheral dimension of the

nibs

144 and 146 to limit the rotational movement of the knob with respect to the rotor. For example, the

leg nibs

144 and 146 might have a 30 angular dimension and the recesses have 48, to allow the knob angular freedom of plus or minus 9.

In operation, rotation of the knob 24 will cause the tongue or reed 136 to engage the side walls of slot 138 causing the tongue to twist as the knob is further rotated. When the torque thereby applied to the rotor is sufficient to overcome the restraining force between the

radially extending corrugations

102 and 104 and the mating radially extending grooves in the clamping member 14, the wiper arms extending from the

arm units

18 and 20 will be rotated with a snap action. During the relative rotation between the knob 24 and the rotor 16, the upper surface of the cylindrical portion of the rotor abuts the lower planar surface of the knob. The upper portions of the

legs

140 and 142 may be radially enlarged to engage the inner wall of the rotor to form an additional bearing surface.

The limits of rotation of the energy storing plastic knob 24 with respect to the switch proper are determined by the two depending reinforced

knob ribs

152 and 154 alternately engaging the upturned tang 156 of the mounting cover 22, as shown in FIG. 7. If only a portion of the switch contacts are to be employed, the rotation of the knob 24 may be further limited by providing an additional upstanding tang on the cover 22 spaced at the desired location. By so modifying the cover 22, the switch may be employed in different electrical units thus providing versatility to keep manufacturing costs to a minimum.

As mentioned before, the switch described herein may be employed in diiferent types of electrical equipment, but the particular embodiment described is adapted to control the operation of a three-speed electrically reversible shaded pole fan motor. To complete the understanding of the operation of the switch, a brief description of its function when used with such a motor will be given. Referring to FIG. 9, there is shown a schematic drawing of the contact support assembly 12 and the

selector arm units

18 and 20 connected to a shadded pole motor shown schematically as including a pair of serially connected

shading coils

162 and 164 and three serially connected primary motor coils 166, 168 and 170 to provide high, medium and low speed operation.

As may be seen from FIG. 9, one end of shading coil 162 is connected to contact 30 of the contact assembly, while one end of shading coil 164 is connected to contact 28. The shading coil circuit is completed by connecting a center tap between the two shading coils to contact 34. The

wiper arms

90 and 92 of the shading coil arm unit 20, as seen in FIGS. 6 and 9 are positioned to cooperate with

contacts

28, 30 and 34 as the arm unit 20 is rotated. With the

wiper arms

90 and 92 positioned as shown in FIG. 6, the switch is in the oif position wherein wiper arm 92 is engaged with contact 34 while wiper arm 90 engages the plastic projection 62 so that the shading coil circuit is open. Wiper arm 92 engages contact 34 at all times; and by rotating the knob and rotary assembly in one direction wiper arm 90 will engage contact 28 to close the shading coil circuit to shade motor rotation in one direction. By rotating the arm unit 20 in the opposite direction, wiper arm 90 will engage contact 30, as shown in FIG. 9, to again close the shading coil circuit, but to shade motor rotation in the opposite direction.

As may be seen from FIG. 9, one lead' 174 to be connected to a line power supply is connected to one end of primary coil 166, and the other lead 176 is to be connected to contact 32 of the terminal assembly 12. The various motor speeds may be obtained by selectively connecting the primary motor coils, by means of the switch of the invention, to the pair of

line terminals

174 and 176. More specifically, the end of primary motor coil 166, remote from the line terminal, is connected to contact 36; the end of coil 168 adjoining coil 170 is connected to contact 38; and the opposite end of coil 170 is connected to contact.40..

Wiper arms

98 and 100 of selector arm unit 18 represented by the tips of arm unit 18 in FIG. 9, cooperate with the switch contacts to determine which coils will be included in the circuit to obtain the desired motor speed. More specifically, wiper arm 98 continuously engages contact 32 while wiper arm 100 selectively engages the

contacts

36, 38 and 40, one of the projections 65, or the plastic projection 64. When the switch is in the off position as shown in FIG. 6, wiper arm 100 engages plastic projection 64 so that the primary motor coil circuit is open. As the switch selector knob 24 is rotated in either direction, wiper arm 98 continues to engage contact 32, connected to power line terminal 176, while, wiper arm 100 initially engages contact 40. In this position, the current passes through all three motor coils in series to obtain low speed operation.

It should be understood that the arm units 18 and 20' are insulated from each other and rotate together as the knob 24, FIG. 6, is rotated. By rotating the knob 24 from the off position, towards the low speed position, wiper arm 90 engages either

contact

28 or 30, depending upon the direction of rotation, to close the shading coil circuit before wiper arm 100 engages contact 40 to close the circuit connecting the primary motor coils. Con versely, when the know is turned from an on to an ofi position, the primary motor coil circuit is broken before the shading coil circuit is broken. By this arrangement, undesirable surge currents are eliminated which might occure if the circuits were connected and disconnected in the reverse order.

As the switch is further rotated, the wiper arm 100 is forced over a projection 65 to engage contact 38 so that the current will then flow through

coils

166 and 168 to obtain medium speed operation. Further rotation of the selector knob 24 will cause the wiper arm 100 to be forced over a projection 65 to engage contact 36 as shown in FIG. 9; and since wiper arm 98 continues to engage contact 32, the current will flow only through primary coil 166 to obtain high speed operation. The projections 65 contribute to the indexing action of the switch as well as to more rapidly extinguish arcing due to the lifting of the arm 100 caused by the projections. Along these lines, it should also be noted that the

contacts

36, 38 and 40 are each provided with a raised detent 158, FIG. 4, on each side of the plastic projection 64 in the arc travelled by the tip of wiper arm 100. The detents prevent slippage of wiper arm 100 and require positive action, to move the wiper arm 100. Thus, it will be appreciated that three-speed motor operation in two directions is obtained by connecting the switch assembly of the inr vention in the manner heretofore described.

The particular embodiment described herein is, of course, merely an example of the invention, and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention in its broader aspects. For example, the plastic projections 65 formed on the thermoplastic support plate 60 and the portion of projection 64 positioned in the path of the tip of wiper arm 100 may be eliminated from the plate 60 and replaced by apertures through which comparable projections formed on the thermosetting base could extend. The projections on the base 10 could serve the same function as the

projections

64 and 65; but being made of thermosetting material, they would not be deformed in the event of overheating. Further, as previously explained, the invention is not limited to switches for electric fans. The contact and support assembly and the method of manufacturing may be employed in fabricating many different types of switches. Likewise, the energy-storing knob may find useful application in a variety of switches and other devices. Therefore, it is intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of this invention.

Having thus described the invention, what is claimed is;

1. In a multiple position electrical switch,

(a) a thermoplastic support plate having a plurality of projections extending from one surface of the plate;

(b) a plurality of switch contact elements arranged in spaced relation in a single plane between said projections and held in such position by the plate;

to) an enclosing case made of thermosetting plastic material surrounding said contact elements and said support plate and including a plurality of projections to position the contact elements in spaced insulated relation independently of said support plate; and

(d) movable contact means supported by said case for varying the electrical circuits through said switch contact elements.

2. The switch of claim 1 in which some of the projections of said support plate are positioned to engage and separate said contact means from said contact elements as the contact means are moved to their various positions.

3. In a multiple position electric switch,

(a) a plurality of switch contact elements arranged in spaced relation in a single plane;

\(b) a thermoplastic support plate having a plurality of projections extending from one surface of the plate, said plate being positioned in parallel relation to said contact elements with said projections extending between said contact elements to hold said contact elements in insulated spaced relation to each other; 1

(c) means formed integral with the ends of said projections to secure said contacts to the plate;

'(d) an enclosing case made of thermosetting plastic material supporting said contact elements and said support plate; and

(e) movable contact means supported by said case for cooperating with said contacts to vary the elec trical circuits through said switch.

4. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements;

(b) a thermoplastic support positioning said contact elements in spaced insulated relationship;

(c) a thermosetting plastic base and clamping member holding said support and said assembled contact elements therebetween, said base and clamping member being made of material capable of withstanding temperatures substantially higher than said thermoplastic support so that the contact elements will remain in insulated relation even though the support is deformed by excessive heat;

(d) a rotary member extending through an opening in said clamping member to selectively connect said contact elements; and

(e) a plastic knob for rotating said rotary member and including an integral tongue engageable with the rotor and formed to provide energy storage means whereby the rotor is moved with a snap action.

5. The switch of claim 4 wherein said knob is formed with a pair of legs positioned on opposite sides of said tongue and extending in the direction of said tongue, each of said legs having an outwardly extending nib, means defining a pair of arcuate recesses within said rotary member, said legs being positioned within said rotary member with each of said nibs being positioned within a r e spective one of said recesses to limit the rotational movement of said knob with respect to the rotary member and hence the energy which may be stored by the knob.

6. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements:

(c) a thermosetting plastic case enclosing said support and said assembled contact elements;

7. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contact elements;

() a plastic base and clamping member holding said support and said assembled contact elements therebetween, said base and clamping member being made of material capable of withstanding temperatures substantially higher than said thermoplastic support so that the contact elements will remain in insulated relation even though the support is deformed by excessive heat;

(d) a rotary member extending through an opening in said clamping member to selectively connect said contact elements, said rotary member and said clamping member having mating detent means to restrain rotation of the rotor; and

(e) a plastic knob for selectively rotating said rotary member and including an integral tongue engageable with the rotor and formed to provide energy storage means whereby said rotor is moved with a snap action.

8. A multiple position, snap-action, electrical switch comprising:

(a) a plurality of contacts;

(b) means supporting said contacts in spaced insulated relation;

(0) a rotor supported by said supporting means and carrying contact means cooperating with said contacts for completing the various switch circuits;

(d) a plastic knob selectively rotating said rotor including an integral plastic tongue engageable with the rotor to provide energy storage means whereby said rotor is moved with a snap action when said knob is rotated;

(e) a pair of diametrically spaced legs formed integral with said knob and extending on opposite sides of said tongue;

(f) means defining a pair of arcuate recesses within said rotor; and

(g) stop means formed integral with said legs extending into said recesses to limit the rotational movement of the knob relative to the rotor and to thereby limit the rotational energy which may be stored by said knob to obtain the switch snap action.

9. A multiple position action switch comprising,

(a) a plurality of contact elements,

(b) a thermoplastic support having integral deformed projections securing said contact elements in spaced insulated relationship,

(c) a thermosetting plastic base receiving said support,

(d) a thermosetting plastic clamping member mating with said base to secure said contact elements therebetween independently of said thermoplastic support,

(e) a rotor received within an opening in said clamping member and having wiper arms extending through openings within the clamping member to selectively connect said contact elements,

(f) said rotor and said clamping member having mating detent means to restrain rotation of the rotor, and

(g) a cover member for securing the rotor to said base and securing said clamping member and said support therebetween.

10. A multiple position snap action electrical switch comprising,

(a) a plurality of contact elements,

(b) a thermoplastic support plate having a centrally located socket and including a plurality of deformed projections securing said contact elements in spaced insulated relationship surrounding said socket,

(c) an insulated base receiving said support carrying the contact elements,

(d) a clamping member to mate with said base to position the support and contact elements therebetween,

(e) a rotor positioned within said insulated base and having a central shaft extending through an opening within said clamping member to fit within the socket in said plastic support,

(f) selector means mounted on said shaft and having wiper arms extending through openings within said clamping member to selectively connect said contact elements,

(g) said rotor and said clamping member having mating detent means to restrain rotation of the rotor, and

(h) a plastic knob including an integral tongue engageable with the rotor to provide energy storage means whereby said rotor is caused to move with a snap action as the knob is rotated.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 8/50 Great Britain.

OTHER REFERENCES German application, 1,084,804, July 1960.

60 BERNARD A. GILHEANY, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,214,536 October 26, 1965 Henry W. Wallace It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 9, line 56, for "action" read snap action Signed and sealed this 27th day of September 1966.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attesting Officer

Claims

1. IN A MULTIPLE POSITION ELECTRIC SWITCH, (A) A THERMOPLASTIC SUPPORT PLATE HAVING A PLURALITY OF PROJECTIONS EXTENDING FROM ONE SURFACE OF THE PLATE; (B) A PLURALITY OF SWITCH CONTACT ELEMENTS ARRANGED IN SPACED RELATION IN A SINGLE PLANE BETWEEN SAID PROJECTIONS AND HELD IN SUCH POSITION BY THE PLATE; (C) AN ENCLOSING CASE MADE OF THERMOSETTING PLASTIC MATERIAL SURROUNDING SAID CONTACT ELEMENTS AND SAID SUPPORT PLATE AND INCLUDING A PLURALITY OF PROJECTIONS TO POSITION THE CONTACT ELEMENTS IN SPACED INSULATED RELATION INDEPENDENTLY OF SAID SUPPORT PLATE; AND (D) MOVABLE CONTACT MEANS SUPPORTED BYY SAID SAID FOR VARYING THE ELECTRICAL CIRCUITS THROUGH SAID SWITCH CONTACT ELEMENTS.