US2429770A - Electric snap-action switch - Google Patents

Description

Oct. 28, 1947. R. POPP ELECTRIC SNAP-ACTION SWITCH Filed Aug 19 1944 a 2. my m W w W h wm w l /fiv/ Q M? 4, J fly 7 Patented Oct. 28,1947

ELECTRIC SNAP-ACTION SWITCH.

Rudolf Popp, Valparaiso, Ind., assignor to McGill Manufacturing Company, Inc., Valparaiso, Ind., a corporation of Indiana Application August 19,1944, Serial No. 550,162

This invention relates to electric snap-action switches and, while it is of general application, it

is particularly useful for embodiment in such switches of the miniature type suitable for controlling relatively low power electrical appliances.

Heretofore there have been proposed numerous snap-action or so-calledv ftoggle type switches, suitable for the control of relativelylow power electrical appliances, such as domestic appli-;

ances of all kinds, electrical hand tools; etc. In general, such switches are provided with 'a small cylindrical bushing which projects-only slightly from the interior of the appliance housing and is held in place by a knurled threaded ring or nut. A small pivoted operatinglever extending from the bushing for actuating the switch is substantially the only protuberance and as a result the switch is very inconspicuous.

Such switches of the prior art, particularly those designed for lower-cost appliances, have left 4 Claims. (01. 200-168) reference is had to the following description something to be desired from the standpoint of sturdiness, reliability and service life. Conversely, those switches designedto incorporate these desirable characteristics have been very complicated in their design and costlyto manufacture.

It is an object of the invention, therefore, to

provide a new and improved electric snap-action switch of extreme simplicity, and therefore of the desired sturdiness, reliability and extended service life. 7 I v In accordance with the invention, an electric low cost, which at the same time does not sacrifice I snap-action switch comprises an elongated base i member of insulation material having a relatively large, generally rectangular, recess opening into anda bridging contact element plvotally sup-,

ported in the rectangular recess about an. axis longitudinal of the base member and adapted to bridge a pair of the spring contact elements. The

switchalso is provided with an insulation cover means for the recesses in the 'base member and a snap-action operating j mechanismjor the bridging contact element including an actuating f lever extending through .the cover means.

For a better understanding of the invention, together with other and further objects thereof,

taken in connection with the accompanying drawings while its scope will be pointed out in the appended claims.

Referring now. to the drawings, Fig. 1 is an exploded perspective view of an electric snap-action switch embodying the invention; Fig. 2 is an enlarged cross-sectional view of the switch of Fig. 1; Fig. 3 is a cross sectional view of the switch of Fig. 1 through the lead-in conductor recesses; while Fig. 4 is an enlarged perspective view of one of the stationary pring contact elements of the switch.

Referring now to the several figures of the drawings, there is illustrated an electric snapaction switch comprising an elongated base member. ill of insulation material, such as a molded thermosetting resin or other plastic material, having :a relatively large, generally rectangular recess. Illa opening into the upper face of the member. The base member i0 also is provided with a plurality of small'lead-in conductor recesses 10b also opening intothe upper face thereof. Preferably, the conductor recesses lllb are vertical and are disposed at least one at each end of the base member i0, preferably one at each corner thereof, as illustrated. -,The bottom of each of the conductor recesses 10b as are not to be used is closed by a thin diaphragm I00, Fig. 3, these recesses being included solely to reduce the amount of material requiredfor the base member l0.

The switch also includes a plurality of identical stationary spring contact elements II, at least one being disposed at each end of the base member. Each of the contact elements I l extends from one of the conductor recesses lllb into the rectangular recess Illa, bridging the portion of the base member l0 therebetween. As shown in Fig. 1, the barrier portion separating the rectangular recess Illa from the conductor recesses lllb is slightly cut away to form a plurality of recesses l0d atthe upper'face of the base member ill in which the contact elements II are seated. The number of spring contact elements will depend upon the circuit-controlling connections desired; for example, if a simple on-oif switch is desired, as indicated by the drawings, two contact elements II will be provided disposed in aligned recesses lllb at opposite ends of the base member 10. On the other hand, if a two-position switch or a two-way three-circuit control is desired, a contact element ll will bedisposed in each of the four conductor recesses Illb, in the latter instance the two contact elementsat one Seating of the spherical enlargement "a of the lever IS in the spherical seat Ila of the bushing l1 provides a dust-tight pivotal Joint for the lever ii. The construction of the insulation element l6b from a simple punchingfrom a sheet of insulation material and its frictional engagement in the recess of the lower end of lever l6 provides an effective and extremely economical construction, The construction of the spring contact elements II from an elongated flat strip bent fiatwise into a U-shaped configuration to bridge the ribs separating the rectangular recess Illa from the several conductor recesses [b, together with their upstanding projections Ild engaged and pressed downwardly by the insulation cover element it, facilitates the assembly of the contact elements il in the switch and at the same time assures that they are permanently held accurately in position without reliance upon the resilient engagement of the ribs in the base member by the contact elements. This arrangement for retaining the spring contact elements'i I also minimizes the eifects of any inaccuracies in the molded base member Ill and of vibration or shock applied to the switch during use. Further, with this con- 25 struction, the bends in the strip are across the grain of the metal, which is usually cold rolled' or drawn, which minimizes cracking at the bands. It is noted that the contact elements II are unlversal; that is, all contact elements are identical, thus doing away with the requirement of righthand and left-hand contact elements usually required in this type of snap-action switch. The use of such a universal contact element requires only a single forming die and reduces the cost of the apparatus.

It will be noted from Fig: 2 that the bridging contact element i2 passes completely over the lower portion of the convex or arcuate contact surfaces llc during the opening and closing of the switch, thus providing a wiping or cleaning action during both operations, which increases the service life of the switch. Further, it is seen that by bringing the conductors l3 downwardly 45 tion extending ent rely through such body portion through the conductor recesses lob, there is pro vided asupport and protection for a substantial portion of the insulation of the conductor adjacent the exposed portion which is connected to a contact element ll, thereby minimizing the breaking or fraying of the conductor insulation at the switch and the breaking of the connection from the conductor l3 to its associated contact Ii. The conductors, however, substantially fill said conductor recesses, thus keeping the interior of the switch mechanism substantially dust-proof.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

What is claimed as new is:

1. In an electric switch, the combination of a generally rectangular base with a central walled cavity having a contact recess in each of two 5 opposite walls thereof, a stationary contact element for each of such recesses, comprising a portion having a pair of ears adapted to engage and maintain a conductor secured therein, a second portion extending into said cavity andg'enerally 5 and upstruck to engage a cover for the switch to maintain the second portion of {the stationary 1 contact in position in the cavity, and each of said two opposite walls having a bearing socket therein adapted to support a bridging contact for piv- 10 otal movement to engage the secondportion of each of said stationary contacts.

2. In an electric switch, the combination of a molded base with a central walled cavity therein having a contact recess in each of two oppositely disposed cavity walls lying in the largest dimension of the base, each of said two walls having a bearing socket therein adjacent the corresponding contact recess, and a stationary contact in each contact recess with each such stationary contact having a, portion extending into the cavity, said two bearing sockets adapted to support a bridging contact which is swingable in an arc across the smallest dimension of the base for engagement with the stationary contact portions.

3. In an electric switch, an insulating base having a central walled cavity and a body portion integral with each of two opposite walls for said cavity, each of said body portions having an iden-' tical recess therein for receiving a stationary contion and comprising a shallow portion intermediate the conductor portion and the cavity, a

stationary contact in each recess, and each base body portion having a bearing socket therein'adiacent a recess, said two bearing sockets adapted to support a movable contact therein for movement to engage the stationary contacts.

4. In an electric switch, an insulating base having a central walled cavity and a body portion integral with each of two opposite walls for said cavity, each of said body portions having an identical recess therein for receiving a stationary contact and such recess comprising a conductor poi"- and comprising a shallow portion intermediate the conductor portion and the cavity, a stationary contact in each recess. having a part thereof in the conductor portion and shallow portion of 0 the corresponding recess and having a part with REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,738,140 Despard et al. Dec. 3, 1929 1,783,665 Meuer Dec. 2, 1930 1,945,487 Johnson Jan 30, 1934 Popp Aug.-15, 1939

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