US2506653A - Electric switch - Google Patents

Description

May 9,'1950 E. M. soRENG ETAI. 2,506,653

ELECTRIC SWITCH Filed sept. 19, 1946 s sheets-sheet 1 5 Edgar M 5mm E. M. SORENG El' AL ELECTRIC .SWITCH Filed sept. 19, 194e 3 Sheets-Sheet 2 May 9, 1950 E. M. soRENG ETAL '2,506,653

ELECTRIC SWITCH Filed Sept. 19, 1946 3 Sheets-Sheet 3 l C* EDQEITM Ecu-'En Laddze A Ean a H dz YF Patented May 9, 1950 ELECTRIC SWITCH Edgar M. Soi-eng, Laddie A. Sanda, and Hardin Y. Fisher, Chicago, Ill.,

assignors to Soreng Manufacturing Corporatior` Chicago, Ill., a corporation of Illinois Application September 19, 1946, Serial No. 698,060

4 Claims.

This invention relates to electric switches, and

y refers more particularly to switches of the change-over type having a single actuator and providing for the selective completion of one or more electrical circuits or combinations thereof.

It is a general object of this invention to provide an improved electric switch which is particularly well adapted for use as a change-over control switch for the burners or hot plates of electric ranges.

Another object of this invention resides in the provision of a new and novel switch of the character described having a single rotatable actuator and an unusually compact and eiiicient arrangement of stationary and movable contacts controlled by said actuator for selectively completing a variety of different circuit connections.

Another object of this invention resides in the provision of an unusually simple switch of the character described wherein the switch parts cooperate with each other to secure the several components in their proper positions with a minimum of fastening means.

Another object of this invention resides in providing a cam operated switch having a plurality of adjacent cams with movable contactors capable of lbeing arranged closely together without interfering with individual actuation of the contactors.

Still another object of this invention resides in the provision of a cam operated change-over switch of the character described having a readily removable end closure which accommodates and removably secures detent means defining the several operative positions of the switch.

A further object of this invention resides in the provision of a stamped terminal and an improved manner of attaching stationary switch contacts thereto.

With the above and other objects in view which will appear as the description proceeds, this invention resides in the novel construction, cornbination and arrangement of parts substantially as hereinafter described, and more particularly deiined by the appended claims, it being understood that such changes in the precise embodilment of the herein-disclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention constructed in accordance with the -best mode so far devised for the `practical application of the principles thereof, and in which:

Figure 1 is a perspective view of the completely assembled switch of this invention looking at the front of the switch;

Figure 2 is a `perspective view of the switch of this invention showing some of its parts disassembled but in the proper order of their assembly;

Figure 3 is a sectional view of the switch of this invention, taken along the line 3-3 in Figure 4;

Figure 4 is a cross sectional view of the switch taken along the line 4-4 in Figure 3;

Figure 5 is a cross sectional View through the switch taken along the line 5-5 of Figure 3;

Figure 6 is a perspective view of one of the switch terminals of this invention showing a movable contacter mounted thereon;

Figure 7 is an exploded perspective view of one of the terminals of the switch of this invention illustrating the improved manner of securing a stationary contact thereto;

Figure 8 is a perspective View of a portion of one of the fixed terminals, showing the stationary contact secured thereto; and

Figure 9 is a circuit diagram showing how the switch of this invention may be employed as a control switch for a hot plate of an electric range.

Figure l0 is a view showing the indexing cam and its associated spring-like members.

Referring now more particularly to the accompanying drawings, in which like numerals designate like parts throughout the several views, the numeral I designates generally the housing for the switch of this invention. The housing has a rear wall 2, which forms a terminal head, and side walls 3 substantially perpendicular thereto and cooperating therewith to define a box-like case having an open front. The case is preferably molded as a unit from insulating plastic, and has its open front enclosed by an insulating plate 4. The plate is of a size and shape to be received within the mouth of the case to iill the same and rests on ledges 4 on the inner surfaces of two opposite side walls of the housing spaced inwardly from the front of the case a distance corresponding to the thickness of the plate so that the plate lies substantially ush with the outer edges of the side walls.

A rectangular `cover plate 5 preferably made as a sheet metal stamping is secured over the exterior 'of the insulating plate 4 against the outer edges of the housing side wall in any suitable manner.

In the present instance, two opposite side walls of the housing areindented to provide external wells 6 opening to the back and sides of the housing with the bottom of the wells located 'a short distance inwardly from the front edges of the side walls.

The actuator or cam shaft 9 of the switch is mounted from the switch housing for rotation on a xed axis substantially centrally of the housing interior and normal to the terminal head 2. The inner end of the shaft is rotatably journalled in a well I in the inner face of the terminal head, while the outer end of the shaft, which projects through the plate 4 and cover 5 to have the usual knob mounted thereon, is journalled in a flanged aperture i I in the cover 5.

A number of axially adjacent cams I3, in the present switch four, are carried by the actuating shaft 9 at its inner end portion to rotate therewith. These cams are preferably formed from insulating plastic, such as Bakelite, molded as a unit directly onto the metal shaft 9.

Terminal strips I4, of a number determined by the number of circuits to be controlled by the switch, are arranged along a pair of opposite side walls 3 of the housing and extend in the direction of the shaft axis. In the present instance, the switch is shown provided with one group I4' of four terminal strips TI to T4, inclusive, arranged in a line along one side wall of the housing and another group I4." of three terminal strips T5 to T'I, inclusive, arranged in a line along the opposite side wall of the housing. The lug or hook-up ends I5 of all of the terminal strips except T1 project through substantially close fitting slots I6 in the terminal head 2 to be exposed at the back of the switch and provide for securing electrical connections thereto. The remaining terminal strip T1 has a medial right angle bend, and its lug or hook-up end projects laterally through a suitable slot in the adjacent side wall of the housing for line hook-up.

The terminal strips I4 are preferably formed of strip brass, and two of the group I4', namely TI and T3, are preferably straight and have shoulders IB thereon provided by a small lug struck outwardly from the strip as seen in Figure 6. This shoulder abuts against the inner side of the terminal head to define the extent to which the lugs I5 project at the back of the switch. Shoulders I8' are formed on the terminal strips T2, T4, T5 and T6 by a pair of opposite perpendicular bends which serve to offset the lugs I5 from the bodies of the strips, thus providing adequate clearance between the lugs I5 at the back of the switch and precluding the possibility of short circuiting of the bare ends of the wires connected to them.

The terminal strip T1, as stated, has its lug I5 bent at right angles from its body to project through the adjacent side wall of the switch, and this lug rests directly on the inner face of the terminal head. A spur (not shown) projects from the strip T'I into a suitable cavity in the head 2 to preclude inward displacement of the strip T1 except by tilting it to withdraw said spur from the cavity.

A pair of insulating strips I9 extends across the front of the housing over the forward ends of the terminal strips. These insulating strips I9 are supported on ledges I1 on the side walls of the housing spaced inwardly from the ledges 4' a distance equal to the thickness of the strips I9, so that the plate 4 rests thereon as well as on its ledges 4', with the strips secured in position by the insulating plate 4.

Slots in the insulating strips I9 receive lugs d 2 I, protruding from the forward ends of the terminal strips, and cooperate with the slots I6 in the terminal head 2 to hold the terminal strips I4 securely in their proper positions within the housing. Shoulders 22 at the forward end of the terminal strips it abut againstthe inner .surfaces of the insulating strips to prevent endwise movement of the terminal strips within the housing.

Each of the strips T5, T6 and T'l has a stationary contact 23 secured thereto (see Figure 7) For this purpose a pair of closely adjacent notches 24 are cut or otherwise formed in one side edge of each of these terminal strips, with the edge portion separating the notches forming in effect a rivet 25. A substantially rectangular strip 26 of a conductive contact metal, such as silver, having a central aperture 25' therein, is received snugly in the notched portion of the terminal strip with the rivet 25 passing through the aperture 25' and peened-over onto the contact strip to rivet the same to the side edge of the terminal strip, with the strips sov connected perpendicular to one another.

The rectangular pieces 25 thus form a pair of contact surfaces, at opposite sides of their peenedover lugs or rivets 25, for the terminal posts T5, T6 and Tl, designated I and C2, C3 and Cd, and C5 and C6, respectively.

In the switch shown, the contacts 26 on the posts T5 and T6 face each other, while the contact 26 on the post Tl faces the post T6.

There are four movable contactors which are identified by the numerals MI, M2, M3 and M4 in the switch illustrated. The contactors are formed from strips of flexible conductive material, such as spring brass, and are of a length to extend substantially across the interior of the housing I between terminal strips of the two groups I4 and id" therein.

All of the contactor arms have an attaching end 28 bent atwise at right angles to the arm to provide for securement of each arm to one of the terminal posts. These attaching ends are secured iiatwise against one fiat face of their terminal posts, as by rivets 28', with the at sides of the arms parallel to the lengths of the post.

A contact 29, such as a silver rivet, is preferably secured to the free end of each contactor arm for engagement with the fixed contacts 23 on the terminal posts.

The medial portion of each contactor arm is provided with a longitudinal slit 29', and the material on either side of the slit is bent outwardly to opposite sides of the strip to form a camfollower 3D and a stiiener 3|.

In the switch shown, the contactors MI and M2 are carried by the terminal posts TI and T2, respectively, and project in the same direction across the housing from between these posts, at one side of the cam axis, so that the contact end of the arm MI lies between and is cooperable with the stationary contact surfaces CI and C3 on the posts T5 and T6, respectively, and so that the contact end of the arm M2 lies between and is cooperable with the stationary contact surfaces C2 and C4 on the posts T5 and T6, respectively. The contactors M3l and M4 are carried by the terminal posts T4 and T6, respectively, and project in opposite directions across the housing at the other side of the cam axis. This disposes the contact end of the arm M3 adjacent to the stationary contact surface C5 for cooperation therewith, and positions the contact end of the arm M4 between the adjacent edges of the posts T3 and T4 for cooperation with the edge C6 of the post T3.

It will thus be seen that the movable contactor arms are arranged in pairs at opposite sides of the cam axis, and it is important to note that arms are mounted in such positions along the lengths of their respective posts that no two arms lie in the same transverse plane of the housing. In other words, the contactor arms of each pair, though spaced equal distances apart in the direction of the cam axis, are staggered with respect to the contactor arms of the opposite pair.

It is to be understood that while two movable contactors 21 have been shown arranged on either side of the cam shaft 9, this arrangement is merely illustrative, since any desired grouping or arrangement of contactors and terminal post may be employed.

The movable contactors 21 are biased toward the cam axis to have the'r cam followers 30 bear against the peripheries of their respective cams under a degree of spring pressure. Hence, upon rotation of the cams when the shaft 9 is turned, the free contact ends of the movable contactors 21 will be carried flatwise into and out of engagement with one or the other of their cooperating stationary contacts.

Since the cam follower' 30 of each movable contacter 21 is only half as wide as the strip from which the contactor is formed, and since the arms are in staggered relationship, it will readily be seen that relatively narrow cams may be used to advantage for the achievement of a relatively compact, shallow switch housing.

The cover plate is stamped with a shallow well I3I, preferably substantially rectangular in shape, and medially of the cover 5, with the well opening inwardly toward the switch housing. A pair of elongated flexible detent strips 32 is disposed in the well along a pair of opposite sides thereof with their ends received in the corners 33 of the well, and these strips are held in place in the well by the insulating plate 4. The medial portions of the strips 32 are bent toward each other to form opposite detent nubs 34 which yieldingly simultaneously engage in the tooth spaces of a substantially gear shaped indexing cam 35 on the shaft 9 to define detents at each of the operative positions of the switch.

Although the indexing cam 35 is situated in the well at the exterior of the plate 4, it is preferably molded integrally with the cam unit I3. It will be readily seen that the strips 32 are secured in place by compression between the indexing cam 35, acting upon their medial portions, and the corners 33 of the well ISI, against which the ends of the strips react.

As may `be seen from Figures 4 and 5, the movable contactors 21 may be arranged with their free ends at either side of the housing, or at both sides thereof; and some of the terminal posts I4 may carry both a stationary contact 23 and a movable contact 21. The cams I3 must, of course, be designed to flex the contactors 21 accordingly. It will be understood that the cams may be constructed to aord full 360 rotation of the cam shaft 9 or some limitation may be placed on its movement by appropriate means, to fulfill the requirements of the particular installation of the switch. It is thus possible to adapt the switch of this invention to provide a large number of combinations and permutations of circuit connecf tions, suitable for a wide Variety of applications.

With the particular switch shown, the number and arrangement of the switch elements, including the cams I3, is such as to provide a total of seven different energizing circuits for a pair of resistances RI and R2 comprising the heating elements of a single hot plate for an electric range, and in addition an off position for the plate Inasmuch as the switch thus has eight positions, arrived at successively by turning the shaft 9 through 360, it will be noted that the indexing cam is provided with eight equi-spaced tooth spaces for engagement by the detent springs. Referring to Figure 9, which is a circuit diagram for the eight position switch hereinbefore described, the letter N designates the neutral or v. line of a 110-220 volt alternating current power supply. The letters LI and L2 designate the two hot or 220 v. lines of the power supply.

In wiring the switch, the hot power lines Ll and L2 are adapted 'to be connected to the lugs of the terminal posts T5 and T1 respectively, while the neutral or 110 lead N is adapted to be electrically connected to the lug of the terminal post T6.

One end of the resistance RI is adapted to be connected to the lug of the terminal post TI through a conductor 5G, and one end of the resistance R2 is adapted to be connected to the lug of the terminal post T2 by means of a conductor 5I. The opposite ends of the resistances RI and R2 are joined by a conductor 52 which connects through another conductor 53 to the lug of the terminal post T.

In the diagram, the switch is shown in the off position and it is to be understood that the cams for each of the movable contactors 21 are designed to complete a total of seven diilerent energizing circuits for the resistances RI and R2 upon rotation of the actuator of the switch through 360, with each operative condition of the switch defined by the engagement of the detent nubs 34 and a pair of diametrically opposite tooth spaces in the gear-like indexing cam 35.

By way of illustration, rotation of the actuator to carry the cam assembly I3 from a switch off position, illustrated in the diagram, to a rst operative setting causes the cams to effect engagement of the movable contacts M and M2 with the stationary contact surfaces CI and C4, respectively, carried by the terminal posts T5 and T6, respectively. This irst operative position of the switch constitutes a low heat circuit for the resistances RI and R2, with the circuit completed from the power lines N and LI to cause a current of 110 volts to flow serially through the two resistances.

Simultaneously with the completion of the series energizing circuit for the resistances RI and R2, the cam for the contactor M4 eifects engagement thereof` with the edge C5 of the terminal post T3 to complete an energizing circuit for the pilot lamp 55 through a conductor 55 leading from the lug of the terminal post T3 to one side of the filament of the lamp and through another conductor 51 leading from the other side of the iilament of the lamp to the lug of the terminal post T1, so that the pilot light is energized by the 110 volt circuit provided by the lines L2 and N.

From Figure 4 it will be apparent that the cam for the pilot light contactor M4 is shaped so as to bre-ak the energizing circuit for the pilot light only in the off position of the switch and to maintain the energizing circuit at al1 other positions of rotation of the actuator. Because of the infrequent breaking of the pilot light circuit and the fact that the light draws a relatively low current, the terminal post T3 and the contactar 7 Ml have not been provided with silver contac portions; however, if desired, these may be used.

As will be apparent from the diagram, the conductor i may be connected to either of the terminals T5 or T1 for the power lines LI and L2.

While the exact sequence in which the remaining energizing circuits are established for the resistances Rl and R2 is optional, rotation of the actuator to the next operative position of the switch may, for the sake of illustration, engage the movable contactor M3 with the contact surface C5 carried by the terminal T1, leaving the contactors MI and M2 engaged with the stationary contacts CI and C4. In this second operative position of the switch, the power line L2 is paired with each of the power lines Li and N to provide individual 220 volt and 110 volt energizing circuits for the resistances Rl and R2 respectively.

The cams for the movable contactors Ml and M2 may be so formed as to effect reversal of the positions of these contactors upon rotation of the actuator to the third operative position 0f the switch, bringing the movable contactor MI into engagement with the stationary contact C3 and the movable contactor M2 into engagement with the stationary contact C2. Reversing of the positions of the removable contacts Ml and M2 in this manner eiects a reversal of the energizing potentials for the resistances RI and R2 to produce a third heating value for the hot plate.

A fourth heating value for the hot plate may be readily obtained by rotation of the actuator to the next operative position of the switch if the cam for the movable contactor M2 is formed to disengage the same from the stationary contact C2 and reengage it with the stationary contact C4, without altering the positions of the remaining contactors. This leaves the resistance Rl energized by a 110 volt current and establishes a 110 volt energizing circuit for the resistance R2 as well.

The fth heating value for the hot plate is obtained by further actuation of the switch to its sixth position in which the cams for the movable cont/actors Ml and M2 effect reversal of the preceding positions of these contactors so as to bring the same into engagement with the stationary contacts Cl and C2, respectively. In this position of the switch the conductors 50 and 5I connect with the power line LI, and a 220 volt circuit is completed through both resistances Rl and R2 by means of the conductors 52 and 53 and the closed contactor M3 to give the highest heating value of the hot plate.

The sixth operative position of the switch may be one which produces a simmer heating value for the hot plate. This is readily accomplished by means of the cams for the movable contactors Ml and M2 which in this position place the contactor M2 in a neutral position, disengaged from either of its cooperating stationary contacts C2 and C4, and reengage the. contactor MI with its stationary contact C3. In this operative position of the switch the resistance element Rl is energized by a circuit including the power lines L2 and N, while the resistance R2 is out of the circuit.

In the nal operative position of the switch, obtained by rotation of the actuator to the eighth position, the cam for the contactor MI may be formed to effect movement of the contactor MI to a, neutral position, entirely disengaged from its cooperating stationary contacts CI and C3, with the cam for the contactor M2 effecting movement thereof into engagement with the stationary contact C2. This setting of the switch provides for energization of the resistance R2 by a 220 volt energizing circuit and disconnects the resistance RI from' the power lines.

Rotation of the switch actuator to the next position dened by the gear-like detent cam disengages all of the movable contacts Mi' to M4, inclusive, from their cooperating stationary contacts to place the switch once again in the oiT position.

It is also to be understood that, without the addition of any more movable contactors or stationary contacts, two additional heating values may be obtained merely through the provision of suitably shaped cams for the movable contactors MI and M2, along with a ten station detent cam. In other words, individual 220 volt energizing circuits may be completed for each of the resistances RI and R2 by eiecting separate and successive engagement of the movable contactors MI and M2 with their cooperating stationary contacts Cl and C2. If these latter two stations are added it will be appreciated that but one detent spring strip can be used because the tooth spaces of the ten tooth detent cam 'will not be diametrically opposite one another.

It will be seen from Figure 9 that theswitch of this invention requires fewer movable contactors than the conventional switch to eiect the same control of an electric range burnen From the foregoing description, taken together with the accompanying drawings, it will be readily apparent that this invention provides an improved and greatly simplifled multiple contact electric switch of the type suited for use as a change-over switch for the burners or bot plates of electric ranges.

What we claim as our invention is:

1. A contactor for a cam operated switch comprising: a relatively at elongated spring blade adapted to have one end rigidly secured to a stationary support so that its opposite end is free to be exed iiatwise in opposite directions toward and from a stationary contact of the switch; contact means on the blade at the free end thereof so as to be movable therewith into and out of engagement with the stationary contact upon exure of the blade by engagement of a cam with the medial portion thereof; and said blade having a longitudinal slit at its medial portion, with the material on each side of said slit bent outwardly from the plane of the blade in opposite directions to provide a substantially rigid cam follower at one side of the blade and a reinforcing portion at the opposite side of the blade, said reinforcing portion also being adapted to be used as a cam follower so that the blade may be installed with either of its sides adjacent the cam.

2. A contactor for a cam operated switch comprising: an elongated exible blade adapted to be rigidly secured at one end to a stationary support for fiexure of its opposite end toward and from a stationary contact of the switch by means of a rotatable cam engageable with the medial portion of the blade, said blade being formed from a strip of spring stock having a longitudinal slit in a mid-portion thereof; a cam follower integral with the blade and projecting to one side thereof formed by oisetting the portion of the blade at one side of the slit; and an alternate cam follower projecting from the other side of the blade formed by offsetting the portion of the blade at the opposite side of the slit and thereby enabling the blade to clear a cam axially adjacent to that with which the first named cam follower is engaged. said two offset portions resulting in foreshortening of the blank from which the blade ls formed so that said offset portions have substantially the same metal thickness as the remaining portions of the blade, and said offset portions cooperating with each other to stiffen the medial portion of the blade.

3. In an electrical switch of the type having a housing and wherein rotation of a single rotatable actuating shaft projecting from thehousing selectively effects completion of different electrical circuits: a cam unit in said housing fixed on said shaft to rotate therewith and having a plurality of closely adjacent peripheral cam surfaces thereon; a plurality of spring blade switch contactors each xed at one end with respect to the housing and lying crosswise of the shaft axis with one nat face facing the periphery of the cam unit and biased toward engagement therewith, each of said blades having a width such as to overlie a pair of axially adjacent cam surfaces on the unit and each blade having a longitudinal slit in a portion thereof opposite the cam unit; a cam follower integral with each blade riding on the periphery of one of said cam surfaces which the blade overlies and formed by onsetting the side edge portion of the contacter blade at one side of the slit a distance to one side of the plane of the blade; and reinforcing means for said slit portions of the blades formed by offsetting the side edge portion of each blade at the other side of the slit therein a distance to the opposite side of the plane of the blade, said offset reinforcing portions of the blades -providing clearance between each blade and the other of the cam surfaces which the blade overlies.

4. In an electrical switch of the type wherein rotation of a single rotatable actuating shaft selectively effects completion of different electrical circuits: a plurality of axially adjacent cams fixed on said shaft to rotate therewith; a plurality of relatively fixed terminal posts spaced from the cam axis and extending lengthwise thereof at opposite sides of the cam axis; a plurality of bladelike contactors lying crosswise of the shaft axis. each having its middle portion resting on the periphery of one of said cams and its opposite ends disposed adjacent to terminal posts at opposite sides of the shaft axis, with contactors on opposite sides of the shaft disposed in common planes normal to the shaft axis, each of said contactors being substantially wider than the cam with which it cooperates and having a longitudinal slit in a mid-portion thereof; a cam follower integral with the contactar and projecting to one side thereof formed .by offsetting the portion of the contacter blade at one sideof the slit; stiffening means for the medial portion of the contactor projecting to the other side of the blade formed by offsetting the portion of the blade at the opposite side of the slit a distance sufficient to clear the periphery of the cam axially adjacent to that with which the contactor cooperates; and means mounting each contactor by one end thereof on terminal posts adjacent to the ends of the contactors with the contactors arranged at opposite peripheral sides of the cams so that rotation of the cams effects movement of the opposite ends of the contactors toward and from engagement with contact surfaces on terminal posts adjacent thereto.

EDGAR M. SORENG. LADDIE A. SANDA. HARDIN Y. FISHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,317,203 Lynch Sept. 30, 1919 2,059,712 Schellenger Nov. 5, 1936 2,203,224 Kimball June 4, 1940 2,243,566 Kimball May 27, 1941 2,317,967 Tuttle Apr. 27, 1943 2,350,967 Nunes June 6, 1944

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