US2896041A - Switch - Google Patents

Description

F- C. SCHWANEKE 'July 21, 1959 SWITCH Filed May 17, 1957 Init ' INVENTOR: FRED C. Sc WANEE FIG. 6-

F, c. ScHwANEKE 2,896,041

swITcH lFiled May 17, 1957 2 Sheets-Sheet 2 FIG, 8

INVENTOR: I

-FRED C. SCH-WANEKE BY SWITCH Fred C. Schwaneke, Chicago, lll., assignor to Dormeyer Corporation, Chicago, Ill., a corporation of Illinois Application May 17, 1957, Serial No. 659,816

7 Claims. (Cl. 200-73) This invention relates to a snap-acting switch, and more particularly to an A.C.D.C. switch wherein means are provided for biasing a pair of electrical contacts into and out of circuit-making relationship by a snap action which is self-limiting, and having application in a construction for obviating contact-destroying arcing during such makeand-break action.

In previously available constructions, the amount of snap action into and out of contact relationship between the contact elements of the switch has not been controlled, with the result that deterioration of the contacts or fatigue of the contact blades from uncontrolled movement out of contact, was produced. Also, it has been diliicnlt or impossible to control arcing, with the result that the contacts have been damaged from this cause as well.

Accordingly, it is an object of the present invention to provide means for limiting snap action of Contact blades produced lby spring means for biasing the contact blades out of contact relationship.

Another object of the invention is to provide a switch in which a contact-receiving aperture is formed in an electrolytic support element of phenolic or other suitable resin which gives oli an inert gas when subjected to flame arc radiation. A resiliently mounted oup means is disposed in normally sealed relationship with the phenolic member below the aperture. The cup means cooperates with the electrolytic support to limit air access to the area where the break between contacts occurs. Moreover, as soon as the resilient mount for the other contact leaves the face of the phenolic member on the other side against which it was resting in closed position, the displacement of the other contact upwardly counters any movement of air into the arcing area by tending to pull a vacuum adverse to such air movement.

Another object of the invention is to provide spring means for biasing the contacts of the switch described to off position, including an extension thereon for limiting the travel of the snap or rapid acting contactcarrying blade or blades away in their movement to prevent overstrain and fatigue of the blades and preserve the calibration of the switch, including an improved spring mounting for switch blades.

Other objects and advantages of the invention will become apparent as the description proceeds in accordance with the drawings, in which:

Figure 1 is a longitudinal sectional view of a switch according to the present invention taken along the line 1-1 of Figure 2;

Figure 2 is a side elevational view of the switch as shown in Figure l;

Figure 3 is a longitudinal sectional view, similar to that of Figure 1, but showing a second embodiment of the invention;

Figure 4 is a longitudinal sectional view of a third embodiment of the switch of the invention taken along the line `4-4 of Figure 5;

Figure 5 is a vertical sectional view of the switch acnited States Patent OHce 2896041 Patented July 21, 1959 cording to Figure 4, in circuit-making position, and taken along the line 5-5 thereof;

Figure 6 is a sectional View identical to that of Figure 5 but showing the switch in circuit-breaking position;

Figure 7 is a vertical sectional View of still another embodiment of the invention in circuit-breaking position;

Figure 8 is a sectional view identical to that of Figure 7 but with the switch in circuit-making position; and

Figure 9 is a longitudinal sectional view of the switch shown in Figures 7 and 8, and the view is taken along the line 9-9 of the latter.

One of the problems existing with snap-acting switch constructions has been the use of projections on either an actuating contact-carrying blade or a contact-carrying blade to be actuated, which substantially interfere with the effective action of the means for biasing the respective elements into spaced apart, circuit-breaking relation. It has been found that by use of a particular construction of the said biasing means, the necessity of said projections can be completely eliminated, with the same construction serving to limit the action of the said biasing means to a predetermined desired extent.

As seen in Figures l and 2, a snap-acting switch 10 is provided, having an upper contact 12 carriedby a resilient blade 14 and a lower contact 16 carried by a resilient blade 18 cut out from and formed integrally with an elongate actuating blade 20; these blades being connected with suitable terminals (not shown). A substantially C-shaped spring 22 is movably secured to the outer end of the blade 18 and to the free or actuating end of the blade 20 by means of the hook- shaped structures 24 and 26, respectively, defining with the depending arms 28 and 30 of the spring 22 a U-shaped configuration in which an arcuate bottom portion is provided, designated by numerals 32 and 34, respectively, and disposed at an angle relative to the arms 28 and 30 such that when the blade 20 is forced upwardly to open the switch, the arm 30 of the spring bears downwardly against the end of the blade 18 to snap the same downwardly and quickly break the connection between the contacts 12 and 16. The interconnection of the respective hooks 24 and 26 with the Iblades 20 and 18 applies constraining forces thereto which limit relative movement of the blades in the directions stated after the spring 22 is turned past center to snap the blade 1S downwardly. More particularly as seen in Figure 2, this interconnection comprises the outer end of the blade 18, having an opening that reclines therein, an upstanding portion 36 of the hook 26 in the position shown. Hook 24 is held in limiting position with respect to the blade 20 by the end portion of the hook being received within an opening 40 in the blade as confined by a tongue 38, disposed between opening 40 and an enlarged opening `42, between the legs 44 and 46 of the hook. Thus confinement of the hooks in opposite positions limit the separation of the contact blades to prevent overstress.

Referring now to Figure 3, another embodiment of the invention is seen wherein a connection of the hook 24a with the blade 20a is provided, in which the hook 24a is formed with a bifurcated portion forming spaced legs 48 and 50 defining an opening therebetween that receives therein a tongue 56 provided 4by the blade. However, the construction of the hook 26a is such with respect to its connection with the blade 18 that it is retained against overstress in a manner similar to the embodiment of Figures l and 2. The parts bind against movement beyond a predetermined position so as to provide the self-limiting action heretofore explained thereby preserving the life of the contacts 12 and 16 and their supporting blades.

Referring now to Figures 4, 5 and 6, a third embodiment of the invention is shown wherein a switch 57 has a dielectric support element 58 of phenolic or other suitable resin, with a resilient blade 59 secured thereto by means of a rivet 6u or other suitable fastening means electrically insulated from one of the blades by a sleeve washer 60a which preferably rests against the upper face of the support and extend over the opening 77 therein. The blade 59 at one end thereof has a terminal extension 6l depending at the end of support 58, and at the other end thereof connects with a C-spring 62 of suitably resilient material such as spring steel, having one end 64 extending through an aperture 66 at the outer extremity of the blade 59 and provided with a hat extension 68 which extends downwardly at a predetermined angle relative to the blade S9 when the said blade is in overlying, substantially parallel, abutting relationship to the support 58. A second foot 70 is formed at the opposite end of the spring 62 and abuts the underside ofthe support 58 so as to hold the blade in predetermined relationship therewith.

As seen more particularly in Figures 5 and 6, the blade 59 is preferably given an inverted J-shaped camming bend 72 so that it may be cammed into abutting relationship with the support 53 by means of a suitable actuating element 74 having a camming surface 76 complementary to the bend 72 so that when actuated in a direction toward the outer end of the blade 59 and upwardly across the bend 72, it will cam the said blade into the required abutting engagement with the support. Intermediate its inner and outer ends, the blade 59 carries a relatively large depending contact member 75, secured to the blade by a rivet 76a or other suitable means, and adapted to be received in the circular' aperture 77 in the support 5S when the blade is cammed downwardly. A second blade 7S is provided in predetermined spaced relationship below the blade 59 and is secured by any suitable means in substantially parallel relationship thereto (as seen for example in Figure 6).

A contact is carried at the outer end of the blade 7% in registration with the contact 75. In order to prevent arcing between the contacts 75 and 86, a cup 82 is mounted on the blade 76 between the blade and contact Si?, this cup having a depth such as to surround the contact Si) except for the portion thereof projecting into the opening 77. An annular edge S4 is formed peripherally of the contact and is normally biased by blade '73 into sealingly abutting relationship with the lower side of the support 58. The action of the blade 59 as it moves upwardly, as shown in Figure 6, is limited, as noted, by the foot 7d in its abutting relationship with support so as to maintain the alignment of the parts, and also to hold the Contact 7S in predetermined position for downward movement into contact with the element Sh. Also, as seen in Figure 5, the foot 63 at the opposite end of the C-spring 62 engages with the blade 5iE while the foot 7u is pressed against support 58 when the blade 59 is moved downwardly to cushion the contacts further; and to provide an immediately effective breaking action by biasing the blade upwardly when it is released by the member 74.

When the blade 59 is actuated downwardly to establish contact relation between elements 75 and 80 it will be noted that contact has a length such as to move contact and cup downwardly, whereby a good electrical connection is made between the contacts. Also, the spring action of blade 78 cushions and maintains the contact during this movement. The displacement of the air within the aperture 77 by the movement of the contact 75 thereinto and the maintenance of iirrn contact produced by the downward movement of the blades 59 and 7S thus provides a condition favorable to inhibiting arcing and maintains the usefulness and shape of the contacts far beyond expectancies for contacts with presently available switches.

Referring now to Figure 6, when the blade 59 is permitted to be moved upwardly, to separate the contacts 75 and Se by retraction of the actuating means and the spring action of the C-spring 62 as described, the cup 82 will again move into abutting relationship with the support 58 to seal off the interior of the cup around the lower and upper contacts 75 and 80 and to start the air moving upwardly through the aperture 77 for vertical movement of the air along the sides of the contact. Thereupon, upward movement of the blade 53 and the contact 75 will substantially draw or accelerate upward linear movement of the air past the contact area. This movement of air through a restricted nozzle defined between the contact 75 and edges of the opening 77 provides an inertia to the arc under conditions which simulate partial vacuum so that as the contacts pull an arc, the air does not redirect its ilow towards the arcing area. This serves to prevent arcing and resultant contact damage during circuit breaking action. Also, the dielectric characteristic of the phenolic support 53 to produce gas under arc radiation as described in Del Monte Patent No. 2,293,701 is effective to further dampen and inhibit electrical activity.

Referring now to Figures 7 through 9, yet another embodiment of the invention is seen, showing that the spring blade 73a need not be fastened directly below the blade 59a, but may be rotated 180 with respect thereto and fastened at the opposite end of the support 58a. Also, the blade 59a is biased upwardly out of contact with the blade 73a by its own structure, so that the contact 75a of the blade 59a is normally disengaged from the contact Stia on blade 78a without the use of a spring such as the spring 62 of the previously described embodiment. It will be appreciated, however, that the spring limiting means disclosed herein has great utility in avoiding metal fatigue and maintaining the parts in predetermined alignment.

Although I have herein set forth and described my invention with respect to certain principles and details thereof, it will become obvious to those skilled in the art that these may be Varied without departing from the scope of the invention, as set forth in the hereunto appended claims.

I claim:

1. A switch `for providing arc-free electrical contact action comprising a pair of resilient contact-bearing blades, a dielectric member interposed between said blades, said dielectric member delining an aperture therein dimensioned cross sectionally to substantially correspond to the cross sectional `dimensions of the contacts, said blades being mounted to dispose their contacts in a position wherein contact lwill be made within the boundaries of the upper and lower surfaces of said dielectric member, one of said blades carrying a cup normally biased thereby into sealing relationship with said member peripherally of said aperture and the other blade being adapted to close the other end of the aperture, said other blades and said cup being spaced apart a distance greater than the thickness of said dielectric member, snap-acting means for springing said blades into and out of circuitmaking relationship, and limit means on said snap-acting means for limiting the movement of said blades out of contact whereby to preserve the said positioning of said blades.

2. A switch for providing arc-free electrical contact action comprising a pair of resilient contact-bearing blades, a dielectric member interposed between said blades, said dielectric member `defining an aperture therein dimensioned cross sectionally to substantially correspond to the cross sectional dimensions of the contacts, said blades being mounted yto `dispose their contacts in a position wherein contact will be made within the boundaries of the upper and lower surfaces of said dielectric member within said aperture, one of said blades carrying a cup and normally biased to carry the cup into sealing relationship with said member peripherally of said aperture, snap-acting means for springing said blades into and out of circuit-making relationship, limit means on said snap-acting means for limiting relative outward movement of said blades when opened to preserve the said positioning of said blades, said cup and said member limiting relative movement of said blades towards each other when closed to prevent excessive force from being exerted on said blade that would create distortion in the contacts.

3. The combination called for in claim 1 in which the dielectric member has an opening spaced from said aperture of predetermined width, one of said blades extending over one edge of the opening and having a slot therethrough, said snap-acting means comprising a C spring with narrow tongues at opposite ends defining shoulders, one of the tongues extending through said opening and engaging the lower face of said member with a shoulder adjacent said Itongue engaging the upper surface of the said member, and the other tongue extends through said slot with a shoulder adjacent said other tongue engaging the upper surface of said one of the blades, the tongues beyond their respective opening and slot being disposed outwardly away from each other -at an angle greater than 90.

4. A switch for providing arc-free electrical contact action comprising a pair of resilient contact-bearing blades, a dielectric member interposed between said blades, said dielectric member defining an aperture therein dimensioned cross sectionally to substantially correspond to the cross sectional dimensions of the contacts, said blades being mounted to dispose their contacts in a position wherein contact will be made within the boundaries of the upper and lower surfaces of said dielectric member, one of said blades carrying a cup normally biased thereby into sealing relationship with said member peripherally of said aperture, snap-acting means for springing said blades into and out of circuit-making relationship, and limit means on said snap-acting means for limiting the movement of said blades out of contact whereby to preserve the said positioning of said blades, said cup being adapted to be moved downwardly out of engagement with the dielectric member and being adapted to cushion the contact between said blades.

5. A switch for providing arc-free electrical contact action comprising a pair of resilient blades, a dielectric support member interposed between said blades, said dielectric member dening an aperture, a contact on each of said blades having a diameter approaching the diameter of said aperture, said blades being positioned for effecting circuit-making contact of said contacts within said aperture, and cup means on one of said blades biased thereby into abutting engagement with the said dielectric support member, said cup means being disposed coaxially around the contact carried by said one blade and being movable out of engagement with said dielectric support member for a slight interval following the making of contact between said contacts, movement of the contact on the other of said blades into said aperture forcing air out of said aperture, said dielectric support member cooperating with said cup and contact means to prevent arcing in said switch and to preserve the calibration and life of said contacts.

6. A switch for providing arc-free electrical contact action comprising a pair of resilient blades, a dielectric support member interposed between said blades, said dielectric member ydefining an aperture, a contact on each of said blades having a diameter approaching the diameter of said aperture, said blades being positioned for effecting circuit-making contact of said contacts within said aperture, cup means on one of said blades biased thereby into abutting engagement with the said dielectric support member, said cup means being disposed coaxially around the contact carried by said blades and being movable out of engagement with said dielectric support member for a slight interval following contact between said contacts whereby movement of the contact on the other of said blades into said aperture is effective to force out air therein, said dielectric support member cooperating with said cup and contact means to prevent arcing in said switch and to preserve the calibration and life of said contacts, Iand spring means connecting said blades, said spring means including a bowed, resilient connecting strip and a limit element at one end of said strip configured to 4be disposed at an angle relative to a blade connected by lsaid spring means in one position of said switch and to be disposed in abutting, substantially parallel relationship with said blade at another position of said switch.

7. A switch for providing arc-free electrical contact action comprising a pair of resilient blades, a dielectric support member interposed between said blades, said dielectric member dening an aperture, a contact on each of said blades having a diameter approaching the diameter of said aperture, said blades being positioned for effecting circuit-making contact of said contacts within said aperture, Ycup means on one of said blades biased thereby into abutting engagement with the said dielectric support member, said cup means being disposed coaxially around the contact carrier by said blades and being movable out of engagement with said dielectric support member for a slight interval following contact between said contacts whereby movement of the contact on the other of said blades into said aperture is eiective to force out air therein, said dielectric support member cooperating with said cup and contact means to prevent arcing in said switch and to preserve the calibration and life of said contacts, and spring means interconnecting said one of said blades and said member, said spring means including a bowed, resilient connecting strip and a limit element at one end of said strip configured to be disposed at an angle relative to the blade connected by said spring means in one position of said switch and to be disposed in abutting, substantially parallel relationship with said blade at another position of said switch to limit the movement of said one blade away from said member.

References Cited in the le of this patent UNITED STATES PATENTS 2,293,701 Delmonte Aug. 25, 1942 2,537,682 Lfungfeldt Jan. 9, 1951 2,540,336 Kaser Feb. 6, 1951 2,687,278 Christensen Sept. 14, 1954 2,694,117 Bakke Nov. 9, 1954 2,753,413 Anderson July 3, 1956

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