US2646484A - Sequential double contact switch - Google Patents

Description

. Patented July 21, 1953 SEQUENTIAL DOUBLE CONTACT SWITCH Adrian J. Vaksvik, Elkhart, Ind., assignor to Chicago Telephone Supply Corporation, Elkhart, Ind., a corporation of Indiana Application October 14, 1950, Serial No. 190,158

7 Claims. (Cl. 206-164) This invention relates'to electric switches and refers more particularly to switches intended for use in radio and television apparatus.

The main purpose of this invention is to provide a switch which is simple in construction, economical to produce and so designed as to have a stable low contact'resistance throughout the life of the switch.

To this end it is an object of this invention to provide an electric switch having two sets of sequentially engaged contacts so arranged that initial switch closure and final opening occurs between one set of contacts while the other set carries the load during the closed condition of the switch, and in which closure of th second set of contacts takes place before disengagement of the first or initially engaged set of the contacts. This arrangement assures low contact resistance at the second set of contacts which carriesthe load during the closed condition of'the switch since it confines any arcing which might occur to the other set of contacts between which the switch is initially closed and finally opened.

Another object ofthis invention is to provide a switch in which the contacts engage and disengage with a wiping action so that the contact surfaces will be kept as clean as possible.

More specifically it is an object of this invention to provide a switch in which the movable contact comprises a spring blade anchored at one end with itsfree end portion overlying the stationary contact to be flexed down into switch closing engagement therewith by switch closing movement of the actuator.

Still another object of this invention is to provide a switch of the character described in which the snap action opening characteristic of quick break spring tog le switches is obtained entirely without the need for springs other than the inherent resiliency of the spring blade which forms the movable contact.

A further object of this invention is to provide a switch of the character described which may be closed and opened by a relatively short angular travel of its rotatable actuator so that the major portion of the full turn of the actuator may be devoted to the adjustment of a Variable resistor mounted in tandem with the switch.

A still further object of this invention is to provide a switch having but a few relatively strong parts so as to assure long life and economy in production. I

With the above and other objects in view, which will appear as the description proceeds, thisinvention resides in the'novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise mbodiment of the hereindisclosed 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 according to the best mode so far devised for the practical application of the principles thereof, and in which:

Figur 1 is a side View of a switch embodying this invention, a part of its casing or housing being broken away and shown in section;

Figure 2 is a rear view of the switch with part of its casing or housing broken away and in section and with the anchoring and terminalrportions of the movable contact broken away and in section;

Figure 3 is a side view with parts broken away and in section, taken substantially on the plane of the line 33 in Figure 1;

Figure 4 is an exploded perspective view of the switch illustrating particularly the relationship between the contacts and the relationship between the movable contact and the switch actuator; an

Figure 5 to 5D are diagrammatic views illustrating the relationship of the parts during the various positions of the switch:

Figure 5 showing the switch open;

Figure 5A illustrating the initial closure and zvipiing action between the first closed set of conac s;

Figure 5B illustrating the transitory instant when both sets of contacts are engaged and the load is transferred from the first closed set of contacts to the other set of contacts;

Figure 5C illustrating the switch closed and the detent on the actuator which provides snap action about to ride under the contact carried driving abutment; and

Figure 5D illustrating the switch in its fully closed condition.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts, the numeral 6 indicates the base of the switch which as is customary is formed of insulating material and preferably is secured in the bottom of a cup-shaped casing or housing 7.

Mountedupon the inner face of the base 6 is a stationary cont-act 8 and a movable contact taching ears or tongues 10 projecting therefrom 3 and passing through the base 6 to be clinched over as at H to securely mount the contacts in place. Each contact also has a terminal portion l2 which projects through the base for the reception of conductor wires (not shown).

The stationary contact '3 has a fiat arcuate main portion l3 which overlies the inner face of the base which be considered the top of the base, and at its extremity remote from its anchorage has an upturned lip I l. As will appear hereinafter, this lip and more particularly the extreme edge thereof farthest from the base provides one contact portion while the outer face of the flat part l3 provides another contact portion. Thus the stationary contact has two contact portions offset with one another and with one farther from the top of the base than the other.

The movable contact 9 is essentially a spring lade anchored to the base at one end with its free end portion 55 overlying the stationary contact. It is roughly arcuate in formation and its anchored end is secured to the base in the manner described, i. e. by tongues l0 passing through the base and clinched over as at H. is bend. it spaces the main body of the movable contact from the front or top face of the base and from the stationary contact thereon, from which position it may be fiexed into switch closing position against the resili nce of the blade. Such flexure may be imparted to the blade-like movable cont-actor by a rotatable driver if fixed upon an actuator shaft l8 which is constrained to retate about the axis of the switch by being journailed in a bearing l9 mounted upon a wall 28 of insulating material closing the open side of the housing '5.

The wall 2&3, if desired, may also serve as the base of a conventional volume control the contactor of which is carried by the driver ll. This tandem mounting of switch and volume control is of course, common practice in the art.

Switch closing movement or rotation of the 'ctuator is translated into fiexure of the bladelike movable contact by the camming action of cooperating driving abutment-s on the spring blade and the actuator or more specifically its driver 52. A finger 2! struck out from the middle portion of the spring blade provides one of these abutments; the other is one edge 22 of a radial recess or notch 23 in the actuator driver. When the switch is open the finger projects into the recess or notch, and since the finger 2| extends from the body of the switch blade at an inclined angle with respect thereto, it is evident that its engagement in the recess or notch precludes rotation of the actuator in one direction and thus may be used as a rotation limiting stop to identify the open position of the switch. During rotation of the actuator in the opposite direction the edge 22 of the recess or notch reacts against the inclined back face of the finger 2! to force the finger out of the recess or notch and thereby flex the blade into switch closing engagement with the stationary contact.

The outer extremity of the spring blade is turned down as at 24 so that like the stationary contact it also has two contact portions, one of which is the edge of this downturned lip 24 nearest the base and the other, the flat portion of the blade overlying the lip Id of the stationary contact. There are, therefore, two sets of contacts, one comprising the lip 24 and the underlying fiat portion l3 of the stationary contact and the other comprising the lip I4 of the stationary contact and the overlying free end portion l5 of the spring blade. These contact portions are so disposed with respect to each other, the spacing between the base and the actuator, and the height of the finger 2| that during closure of the switch contact is initially established between the first designated set of contacts, i. e. the lip 24 and the fiat part l3. This is illustrated in dotted lines in Figure 5A.

After intial switch closing engagement is thus established the next few degrees of rotation of the actuator imparts a wiping motion to the spring blade as indicated in full lines in Figure 5A. This follows from the fact that the bend it at the anchored end of the blade allows some displacement of the blade with respect to its mounting and being arcuate in shape this displacement of the spring blade can be characterized as torsional resiliency so that its free end portion is carried along with the rotation of the actuator due to the thrust imposed thereon by the edge 22 bearing against the back of the finger i.

As rotation of the actuator continues and for an imperceptibly short interval both sets of con ta-cts are engaged as shown in Figure 5B. During this brief instant the load is divided between the initially engaged contacts and the finally engaged contacts.

Continued switch closing movement of the actuator forces the spring finger 2i farther out of the recess or notch 23 and thus flexes the spring blade to cause it to rock about the edge of the lip and thereby lift the extreme end of the blade. i. e. its lip off the stationary contact as shown in Figure 5C, transferring the full load to the finally engaged contact, i. e. the lip it and the spring blade portion [5.

Attention is now directed to the fact that the 5 protruding slightly beyond the fiat inner face the actuator driver 1?. Thus during final ejection of the finger "2| from the recess or notch the spring finger snaps over the ridge 25 and gives the switch a characteristic snap action to indicate full closure.

During opening of the switch, which is offected by retrograde rotation of the actuator, the ridge 25 collides with the finger 2! and thus applies a torque upon the spring blade in the direction to release the blade from its torsional deflection to which it was subjected during closure of the switch and in which condition it would be held by virtue of the relatively great frictional engagement between the contacts. This unwinding of the spring blade produces a wip ing movement between the contacting surfaces of the finally engaged set of contacts.

As the retrograde rotation of the actuator continues and the ridge 25 rides under the spring finger and the finger begins its descent into the recesses or notch 23, the load, i. e., the electrical load upon the switch, is transferred to the initially engaged set of contacts and then finally the switch opens with any are that might occur taking place between the initially engaged set of contacts.

Also, as will be readily apparent, as the ridge 25 rides under the spring finger the manual force required to effect this motion is suddenly and involuntarily released and the finger 2! drops down into the recess with a sudden motion so that in essence the switch opens with a snap action.

From the foregoing description taken in con- .nection with the accompanying drawings; it will be readily apparent to those skilled in this art that the switch of this invention is extremely simple in construction, reliable in action, and economical to produce; and that although no springs are employed, other than the resilience inherent in the spring blade which provides the movable contact, the switch has a snap action characteristic of a quick break toggle switch.

What I claim as my invention is:

1. In an electric switch: a base; a stationary contact on the base having two contact portions both of which face upwardly from the top of the base, one of said portions projecting farther from the base than the other; a movable contact in the form of a spring blade having one end anchored on the base and its free end portion overlying the stationary contact but spaced therefrom by the resilience of the blade, the free end portion of the springblade having a contact portion at its extremity overlying and engageable with the contact portion of the stationary contact nearest the base to thus provide one set of contacts, and having another contact portion overlying and engageable with the contact portion of the stationary contact farthest from the base to provide a second set of contacts; the relative elevations of the contact portions above the base and withrespect to each other being such that upon flexure of the spring blade toward the basethe first and second designated sets of contacts are. sequentially engaged in said order and upon continued flexure of the spring blade toward the base by a force applied thereto medially of its ends, the blade rocks about the stationary contact portion farthest from the base tolift the contact at the extremity of the blade ofi its companion stationary contact portion; an actuator spaced above the base and the stationary contact thereon and constrained to movement in a fixed plane parallel to the base and generally lengthwise of the spring blade; and cooperating driving abutments on the actuator and the medial portion of the spring blade engageable with a camming action durin switch closing movement of the actuator to apply a flexing force toward the base to the medial portion of the spring blade and thereby effect the aforesaid sequential engagement of the two sets of contacts.

2. In an electric switch: a base; a stationary contact on the base having two contact portions both of which face upwardly from the top of the base; a movable contact in the form of a spring'blade having one end anchored on the base and its free end portion overlying the stationary contact but spaced therefrom by the resilience of the blade, the free end portion of the spring blade having two contact portions, one of which is at the extremity of the spring blade and each of which overlies one of the contact portions of the stationary contact so that two sets of cooperating contacts are provided spaced along the length of the spring blade, the movable contact portion at the extremity of the spring blade being nearer the base than the other movable contact portion; the relative elevations of the contact portions above the base and with respect to each other being such that upon fiexure of the spring blade toward the base the first and second designated set of contacts are sequentially engaged in said order and upon continued flexure of the spring blade toward the base by a force applied thereto medially of its ends, the blade rocks about the stationary contact portion farthest from the base to lift the contact at the extremity of the blade off its companion stationary contact portion; an actuator spaced above the base and the stationary contact thereon and constrained to movement in a fixed plane parallel to the base and generally lengthwise of the spring blade; and cooperating driving abutments on the actuator and the medial portion of the spring'blade engageable with a camming action during switch closing movement of the actuator to apply a flexing force toward the base to the medial portion of the spring blade and thereby efiect the aforesaid sequential engagement of the two sets of contacts.

3. In an electric switch: a base; an actuator spaced from and overlying the top of the base; means movably mounting and constraining the actuator to movement in a plane substantially parallel with the top of the base; a stationary contact on the base having two contact portions both facing the actuator but spaced different distances therefrom; a movable contact comprising a spring blade having one end anchored upon the base and its other end portion overlying the stationary contact and by its resilience being spaced from said stationary contact, said free end portion of the spring'blade having two contact portions spaced lengthwise of the blade and both facing but spaced different distances from the base with the contact portion nearest the end of the blade closest to the base; the relative elevations of the contact portions above the bas'e and with respect to each other being such that upon flexure of the spring blade toward the base its contact portion nearest the end of the blade is engaged with its companion stationary contact portion before engagement of the other contact portion of the blade with its companion stationary contact portion and upon continued fiexure of the spring blade toward the base by a force applied thereto medially of its ends, the blade rocks about the point of engagement of the second engaged set of contacts to separate the first engaged set of contacts after a brief instant of simultaneous closure of both sets of contacts; and cooperating abutments on the actuator and the medial portion of the spring blade through which movement of the actuator across the base applies a flexing force to the medial portion of the spring blade toward the base to effect the aforesaid sequential engage ment of the contacts.

' 4;. In an electric switch: a stationary contact having two contact portions ofiset with respect to one another so that one is higher than the other; a resilient blade anchored at one end and having its free end portion overlying the stationary contact and spaced therefrom by the resilience of the blade, said free end portion of the resilient blade having two contact portions offset with respect to one another and spaced lengthwise of the blade with the contact portion nearest the end of the blade higher than the other and opposite the low contact portion of the stationary contact; the relative elevations of the contact portions with respect to one another being such that upon fiexure of the resilient blade toward the stationary contact the set of com-- panion contacts nearest the end of the blade are engaged before the other set of contacts and upon continued flexure of the blade toward the stationary contact by a force applied to the blade medially of its ends, the blade rocks about the stationary contact portion of the second designated set of contacts to separate the first engaged set of contacts; a movable actuator having a part constrained to movement lengthwise of the blade and in a plan fixed with respect to the anchorage of the resilient blade and gen erally parallel to the blade; and cooperating cam means on the blade and actuator engageable upon switch closing movement of the actuator to apply a flexing force to the medial portion of the blade to flex the blade toward the stationary contact and thereby bring about the aforesaid sequential engagement of the two sets of contacts.

5. In an electric switch: a base; an actuator spaced above the base and constrained to rotation about an axis normal thereto and in a plane spaced at fixed distance from the base; a stationary contact on the base with its contact surface facing the actuator; a movable contact comprising a spring blade having a reverse bend at one end portion thereof to provide a short anchoring portion and long resilient free end portion. said free end portion being arcuate and generally concentric to the axis of rotation of the actuator; means rigidly securing the short anchoring portion to the base with the resilient free end portion of the blade overlying the stationary contact and spaced therefrom when free; and cooperating driving abutment-s on the actuator and the medial portion of the resilient blade engageabl with a camming action to translate rotation of the actuator into fiexure of the blade towa and into switch closing engagement with the stationary contact, the reverse bend at the anchored end of the blade providing for some displacement of the blade with respect to its anchorage to thereby give the blade torsional as Well as fiat-wise resiliency so that the camniing ction of the cooperating driving abutments to eifect closure of the switch, in imposing a torsional thrust upon the blade, slightly displaces the same in the direction of the thrust and thereu es the blade to engage the stationary coni to a wiping action.

8. In an electric switch: a base; a stationary t on the base having two contact portions base i the than the other; a movable contact in the form of a spring blade having a re- "\.-SS bend at one end thereof to provide a short anchoring portion and a long resilient free end portion; means rigidly securng the mounting portion to the base with the Zree end portion of the spring blade overlying the stationary contact but spaced therefrom by the resilience of the blade, the free end portion of the spring blade having a contact portion at its extremity overlying and engageable with the contact p tion of the stationary contact nearest the base to thus provide one set of contacts and having another contact portion overlying and en agea able with the contact portion of the stationary contact farthest from the base to provide a sec and set of contacts, the relative elevations of the contact portions above the base and with respect to each other being such that upon flatwise flexure of the spring blade toward the base the first and second designated sets of contacts are sequentially engaged in said order and upon continued flatwise flexure of the spring blade toward the base by a force applied thereto medially of its ends, the blade rocks about the point of contact between the second engaged set of contacts to lift the contact at the extremity of the blade off its companion stationary contact portion; an actuator spaced above the base and the stationary contact thereon and constrained to movement in a fixed plane parallel to the base and generally lengthwise of the Sprin blade; and cooperating driving abutments on the actuator and the medial portion of the resilient free end portion of the spring blade engageable with a camrning action during switch closing movement of the actuator to apply a downward flexing force upon said medial p tion of the spring blade and thereby effect the aforesaid sequential engagement of the two sets of Contacts, the reverse bend at the anchored end of the spring blade providing for some endwise displacement of its resilient end portion with 1'8- spect to the anchorage of the blade to give the blade endwise as Well as flatwise resiliency so that the cannning action of the cooperating driving abutments to effect closure of the switch imposes an end ise thrust upon the blade to slightly displace the same in the direction of the thrust and thereby cause the contact at the extremity of the blade to engage its companion stationary contact with a wiping action.

7. The electric switch of claim 6 further characterized by the provision of a ridge on the actuator contiguous to its abutment and positioned to collide with the abutment on the spring blade during switch opening movement of the actuator, the collision of said ridge with the abutment on the spring blade during opening movement of the actuator applying a thrust upon the blade in the direction to release the blade from its endwise deflection to which it was subjected during closure of the switch and thereby producing a wiping movement between the contacting surfaces of the second closed set of contacts.

ADRIAN J. VAKSVIK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,231,063 Platt June 26, 1917 2,172,397 Meuer Sept. 12, 1939 2,231,541 Lodge Feb. 11, 1941 2,507,381 Morse May 9, 1

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