US3321601A - Electric switch having barriers isolating the several terminals and frameattaching tabs thereof - Google Patents

Description

y 1967 K. H. WALTERICK. ETAL 3,321,601

ELECTRIC SWITCH HAVING BARRIERS ISOLATING THE SEVERAL TERMINALS AND FRAME'ATTACHING TABS THEREOF Filed Feb. 9, 1966 INVENTQRS! KENNETH h. MLTER/CK BY WALTER H. ANTHONY A TTORNEYS 332L661 Patented May 23, 1967 3,321,601 ELECTRIC SWITCH HAVING BARRIERS ISOLAT- ING THE SEVERAL TERMINALS AND FRAME- ATTACHING TABS THEREOF Kenneth H. Walterick and Walter H. Anthony, Levittown, Pa., assignors to Circle F Industries, Inc, a corporation of New Jersey Filed Feb. 9, 1966, Ser. No. 526,299 2 Claims. (Cl. 200-168) This invention relates generally to electrical wiring devices. More particularly, the invention has reference to a switch base, so designed as to provide isolation of electrically conductive elements of the device, in such fashion as to isolate each base-engaged element of the switch from all other similarly engaged, electrically conductive elements.

In the wiring device field, there is an increasing trend toward miniaturization. This trend has resulted in the design of comparatively small switches, especially appliance switches such as are used on electric shavers, radios, record players, vacuum sweepers, etc. Such switches are designed for use with the ordinary house current supply, which generally is supplied at 110 v. A.C. Such switches, in this connection, are designed to operate under rather heavy loads, considering their relatively small size and inexpensive construction, and must pass rigorous tests. It is almost inevitably required that a switch of this type pass tests set up by Underwriters Laboratories. However, it is quite usual for the customer to also require that the switch meet its own test requirements, these being, in some instances, even more demanding than those established by Underwriters Laboratories.

Such tests in almost every instance involve checking the switch for voltage breakdown values, not only between adjacent open contacts, but also (and perhaps more importantly) between each contact or terminal and adjacent metallic components of the device, as for example the frame.

The smaller the switch becomes, the more difiicult it is to meet these requirements, since obviously, the distance between terminals, or between a terminal and an adjacent portion of the switch cover or frame, becomes increasingly less.

The problems discussed above are particularly prevalent in switches such as miniature slide switches, which must be made at a very low cost in order to meet competition, but which must nevertheless be capable of carrying heavy loads and meeting demanding test requirements.

The main object of the present invention is to provide a base for an electrical wiring device, especially a miniature slide switch, that will be novelly designed to provide true isolation of electrically conductive elements of the switch, whether or not said elements are intended to carry current during the normal operation of the switch.

Another object of the invention is to provide .a device of the character stated that will provide the desired isolation despite the provision of minimum distances or gaps between the adjacent elements that are to be isolated from each other.

Still another object is to provide a space for an electric switch that will meet the desirable purposes set forth above, but which will at the same time be capable of manufacture at a very low cost, from a single piece of molded plastic material.

A further object is to provide a switch base as stated which can be manufactured in a single form, but which will nevertheless be designed to deceive different types of wire connectors.

A further object of the invention is to provide a base of the character stated that will include barrier means so formed and arranged as to define a plurality of individual pockets and recesses, each of which will receive an electrically conductive component of the switch, whether said component be a contact, a terminal, or a part of the metallic frame of the switch.

Still another object is to so locate the barriers as to permit the wire leads to extend from the switch or other wiring device in any of a plurality of desired directions. This is particularly important to manufacturers of devices wherein space is at such a premium in an appliance as to require that the wire leads be extended only in a specific, predetermined direction. Such instances arise, for example, when a plurality of the wiring devices are wired together in a harness type of assembly.

Yet another object is to so locate the barriers as to permit limited pivotal or swivelling movement of the terminals, while at the same time preventing such movement from occurring to an extent that would cause the terminal to contact or come too close to an adjacent element of the switch.

In carrying out the invention, we provide a switch base which is of generally rectangular configuration, and which has a pair of barriers symmetrically disposed in respect to the center point of the base. The barriers are integrally formed on the base, which is of electrically insulative material such as a thermosetting phenolic resin.

The barriers are oppositely but identically formed, with each barrier including a transverse rib extending from side to side of the switch, and a pair of longitudinal ribs extending from the center area of the switch toward the adjacent end thereof. The arrangement provides a center recess, side recesses communicating therewith, end recesses, and corner recesses, with each recess being adapted to receive an electrically conductive component of the switch, and to effectively isolate said component from all other conductive parts of the switch or other wiring device.

Other objects will appear from the following description, the claims appended thereto, and from the annexed drawings, in which like reference characters designate like parts throughout the several views, and wherein:

FIG. 1 is a bottom plan view of a slide switch incorporating our switch base invention, a portion of the switch frame being broken away, the switch having permanently connected leads one of which is shown in full and dotted lines in different positions to which it is movable;

FIG. 2 is a side elevational view of the switch in which the base is shown in edge elevation, a portion of the switch frame being broken away;

FIG. 3 is a view similar to FIG. 1 wherein the switch provided with male quick-connect fasteners or tabs; FIG. 4 is a bottom perspective view of the switch base per se;

FIG. 5 is an enlarged perspective view of one of the male fasteners per se; and

FIG. 6 is a perspective view of one of the wire connectors, said connector being shown partially crimped to an associated lead.

Referring to the drawings in detail, the reference numeral 10 generally designates a slide switch having a metallic frame 12 integrally formed with a flat cover portion 14 and with depending side walls 16. The switch includes a slide 18 of electrically insulative material such as a phenolic resin, having a handle 20 extending upwardly through an opening formed in the cover portion 14. The switch would also include, as will be understood, a movable contact reciprocable with the slide. A typical switch mechanism of this type is shown in copending application Ser. No. 526,298, filed Feb. 9, 1966, by Frederick A. Zoda and Walter H. Anthony. Movable contact 21 is similar to that shown in said copending application, and typifies one that can be used.

The switch base constituting the present invention has been generally designated 22, and comprises a generally rectangular, flat, one-piece body 24 which in the illustrated example is molded of a suitable thermosetting phenolic resin having acceptable characteristics as regards resistance to tracking, dielectric properties, strength and low cost. It will be understood, in this connection, that the particular material used might be varied within the scope of the appended claims, so long as it has the desired properties briefly summarized herein.

In any event, the body is formed, longitudinally and centrally thereof, with a straight row of circular apertures 26. In the illustrated example, there are two of said apertures, one at the center point of the body, and the other spaced from the center aperture, along the longitudinal center line of the body. Such a construction provides an arrangement suitable for assembly of the base in a single-pole, single-throw switch. The body could be formed with three apertures along said center line, one at the center and the others equidistantly spaced therefrom, to permit assembly of a single-pole, double-throw switch.

Formed in each side or longitudinal edge of the body is a pair of relatively shallow notches 28, equidistantly spaced from the center point of the side edge, to receive rectangular, depending tabs of side walls 16. Tabs 38 are integrally formed with tongues 32 of reduced width, bendable laterally inwardly into engagement with the underside of the body 24, to assemble the base with the frame 12. Tongues 32, thus, are rectangularly spaced in the assembled condition of the switch components, as shown to best advantage in FIGS. 1 and 3.

Body 24 is formed, in the illustrated example of the invention, with a flat top surface 33, facing the underside of slide 18. The under surface of body 24 is flat, and parallel to the flat top surface 33, except for the provision of barriers generally designated 34.

Barriers 34 comprise an important feature of the invention, and as will be noted, in carrying out this part of the invention, we provide two barriers, identically but oppositely formed, disposed symmetrically in respect to and at opposite sides of the center aperture 26. Thus, the barriers comprise a pair of transverse ribs 36 extending normally to the longitudinal center line of the body, from one to the opposite side edge of said body, the ribs having rounded extremities forming one end of the several notches 28 (see FIG. 4). Each rib 36 is integral with a pair of longitudinal branch ribs 38, the ribs 38 of each pair extending from the transverse ribs 36 associated therewith in a direction toward the adjacent end of body .24. Ribs 38 terminate approximately midway between their associated ribs 36 and the adjacent extremity of body 24, and are equally spaced from the longitudinal center line of the body, in parallel relation thereto.

Ribs 36 are provided with confronting, parallel, intermediate surfaces 40 (see FIG. 1), in the area of the ribs 36 disposed between the branch ribs 38 associated therewith. Ribs 36 are also provided with confronting end surfaces 42, which are offset outwardly from the intermediate surfaces 40 in a preferred embodiment of the invention, that is, the surfaces 42 are spaced from each other a greater distance than are the intermediate surfaces 40.

Defined between the intermediate surfaces 40 of the transverse ribs 36 is a center recess or pocket for a center contact and terminal of the switch. Center recess 44 communicates with side recesses 46 disposed at opposite sides of the center recess and communicating freely therewith, the side recesses being defined between the respective, confronting end surfaces 42 of transverse ribs 36.

The provision of the pairs of longitudinal ribs 38 define end recesses 48 at opposite sides of the center recess 44. End recesses 48 are disposed, as in the center recess 44, medially between the opposite longitudinal edges of body 24. End recesses 48 are completely separated by a wall of electrical insulation from the center recess, due

to the provision of the transverse ribs. End recesses 48,

however, open toward the adjacent extremities of body 24 and due to the termination of the longitudinal ribs 38 short of the extremities of the body, said end recesses correspondingly terminate short of the ends of the body, at the open ends of said end recesses.

Since longitudinal ribs 38 are spaced inwardly from the adjacent side edges of the body, being in fact located substantially midway between each side edge of the body and the longitudinal center line thereof, there are defined corner pockets or recesses 59. The arrangement, as readily noted from FIGS. 1, 3, or 4, produces four, rectangularly spaced corner recesses 59, with each of these being completely separated by a wall of insulation, along two of its sides, from the adjacent recesses 46, 48. The tongues 32 extend into the corner recesses 50, and are thus fully separated from any recess in which a contact and/ or terminal may be located.

By reason of this arrangement, there are defined three recesses for contacts and terminals, each of which is completely separated from any adjacent recess in which a conductive part may be located, said separation being achieved by the barriers 34. It is also to be noted that each of these recesses is fully open toward an end or side of the switch, as the case may be, despite the effective insulation of the recesses from one another, and from the metallic tongues 32. The end recesses open toward the adjacent ends of the switch, while the center recess opens toward each side of the body, so as to permit a lead to extend in either direction laterally of the switch, as required by the mounting conditions of the switch.

It is also important to note that the base formed as shown can receive any of various types of connectors. Two of these are shown by way of illustration. Thus, in FIGS. 1, 2, and 6, we show a pair of crimp-type connectors of conventional design, used for attaching leads permanently to the switch. The connectors have been generally designated 52, and serve the purpose of connecting leads 54 to selected contacts of the switch. Each connector or terminal 52 includes a fiat tongue 56 of widened formation, which is generally octagonal as shown, although it might also be rectangular or even circular. In any event, the width of center recess 44 is such as to confine the tongue 56 rather snugly, while still assuring free movement of the tongue into the recess during the assembly of the switch.

Tongue 56 is integral with an elongated lead-attaching portion, having a pair of opposed, bendable tabs 53 adapted to be crimped into engagement with the stripped portion of the leads, and having also end tabs 6% crimped into engagement with the covering of the lead to provide an insulation grip on each connector.

The tongues 56 are formed centrally with openings adapted to receive rivets 62, said rivets extending through apertures 26 and being provided with rounded heads forming contact surfaces for the switch. A spherically rounded bump 64 on surface 33 corresponds in height and radius to the rivet heads with its center being spaced from the center aperture correspondingly to the center of the end aperture.

The connectors 52, as shown in FIG. 1, extend out of their associated recesses, and are completely separated from each other by the barriers. The connectors ordinarily would be riveted so tightly to the body as not to normally pivot from their assigned positions, since looseness between a contact and its associated terminal is undesirable. Nevertheless, it often happens that in the mounting of the switch, the leads are pulled to one side or another, causing the connector to turn, as shown for example in dotted lines in FIG. 1. By reason of the particular form and arrangement of the barriers, only limited pivotal movement of the connectors is permitted in these circumstances, with said movement being haulted before the connector can come close enough to any other connector, or to any of the tongues 32 of the metallic frame,

to cause arcing between, adjacent contacts, or between aterminal and the frame of the switch. This is an important feature of the invention and results entirely from the particular location of the several longitudinal ribs in respect to each other and in respect to the transverse ribs. The desirable results are achieved, so far as the center terminal is concerned, by the particular form and arrangement of the transverse ribs, extending fully from side to side of the body.

The body can be used interchangeably with connectors 52, and also with male quick-connect terminals generally designated 66. These are also of basically conventional design, and are illustrated purely for the purpose of showing the capability of the switch base for use with diiferent types of connectors. The male terminals 66 are provided with fiat tongues 68 centrally apertured to receive rivets 62, and with connecting blades 70, which may be widened in respect to the tongues to define shoulders 72 partially overlying the ribs 36 as shown in FIG. 3. A reinforcing gusset 74 can be provided at the juncture of the tongue 68 and blade 79.

The terminals 66 are attached by means of the rivets, as shown in FIG. 3, and like the connectors 52, are effectively confined in their associated recesses 44, 48. Complete insulation is provided therebetween, and even though one or more of the terminals should pivot, as for example to the dotted line position shown in FIG. 3, no danger of arcing such as described above, exists.

In the illustrated example, the switches are of the single-pole, single-throw type. They could, however, obviously be of the single-p0le double-throw type. Further, it is possible to use diiferent types of connectors in the same switch, according to special customers requirements. Thus, the same switch might be provided with one terminal 52, and with another terminal 66.

We believe it is also important to note that although the switch base has been shown in association with a slide switch in the illustrated example, it could be used to equal advantage in various other kinds of switches, such as rocker switches, push-type switches, toggle switches, etc.

If desired, the body, when made with the three apertures, the third being at the location of and in substitution for the bump 64, could be assembled in a single-pole, single-throw configuration. In this event one would use a dummy rivet at the location of and serving the same purpose as bump 64.

It is believed apparent that the invention is not necessarily confined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction illustrated and described, since such construction is only intended to be illustrative of the principles of operation and the means presently devised to carry out said principles, it being considered that the invention comprehends any changes in construction that may be permitted within the scope of the appended claims.

We claim:

1. In an electric switch of the type including a flat, rectangular base of electrically insulative material, a frame of electrically conductive material having four rectangularly spaced connecting tabs attaching the frame to the base, a first terminal attached to the center of the base, and at least one second terminal attached to the base in alignment longitudinally centrally of the base with the first terminal, the improvement comprising a pair of identically but oppositely formed barriers isolating the terminals and the tabs one from another, said barriers formed integrally with the base and comprising:

(a) a pair of ribs, one in each barrier, said ribs extending transversely of the base at opposite sides of the first terminal to define between the ribs a center recess and a pair of side recesses communicating with the center recess and opening upon the respective sides of the base, said ribs extending substantially the full distance across the body and isolating the first terminal from the several tabs; and

(b) means extending from the respective transverse ribs in a direction away from the center recess, said means of the respective barriers defining end recesses opening toward the respective ends of the base, said second terminal disposed in one of said end recesses, said means extending as separators between the respective end recesses and the sereval connecting tabs to isolate the tabs from the second terminal.

2. In an electric switch of the class described, the improvement of claim 1, wherein said means of each barrier comprises a pair of longitudinal ribs disposed between the transverse rib of the barrier and the adjacent end of the body, the longitudial ribs of each barrier disposed at opposite sides of the longitudinal center line to define between them one of said end recesses, each longitudinal rib and the transverse ri-b adjacent thereto forming a corner recess, the several corner recesses being rectangularly spaced to receive the several connecting tabs.

References Cited by the Examiner ROBERT K. SCHAEFER, Primary Examiner. H. O. JONES, Assistant Examiner.

Claims (1)

1. IN AN ELECTRIC SWITCH OF THE TYPE INCLUDING A FLAT, RECTANGULAR BASE OF ELECTRICALLY INSULATIVE MATERIAL, A FRAME OF ELECTRICALLY CONDUCTIVE MATERIAL HAVING FOUR RECTANGULARLY SPACED CONNECTING TABS ATTACHING THE FRAME TO THE BASE, A FIRST TERMINAL ATTACHED TO THE CENTER OF THE BASE, AND AT LEAST ONE SECOND TERMINAL ATTACHED TO THE BASE IN ALIGNMENT LONGITUDINALLY CENTRALLY OF THE BASE WITH THE FIRST TERMINAL, THE IMPROVEMENT COMPRISING A PAIR OF IDENTICALLY BUT OPPOSITELY FORMED BARRIERS ISOLATING THE TERMINALS AND THE TABS ONE FROM ANOTHER, SAID BARRIERS FORMED INTEGRALLY WITH THE BASE AND COMPRISING: (A) A PAIR OF RIBS, ONE IN EACH BARRIER, SAID RIBS EXTENDING TRANSVERSELY OF THE BASE AT OPPOSITE SIDES OF THE FIRST TERMINAL TO DEFINE BETWEEN THE RIBS A CENTER RECESS AND A PAIR OF SIDE RECESSES COMMUNICATING WITH THE CENTER RECESS AND OPENING UPON THE RESPECTIVE SIDES OF THE BASE, SAID RIBS EXTENDING SUBSTANTIALLY THE FULL DISTANCE ACROSS THE BODY AND ISOLATING THE FIRST TERMINAL FROM THE SEVERAL TABS; AND (B) MEANS EXTENDING FROM THE RESPECTIVE TRANSVERSE RIBS IN A DIRECTION AWAY FROM THE CENTER RECESS, SAID MEANS OF THE RESPECTIVE BARRIERS DEFINING END RECESSES OPENING TOWARD THE RESPECTIVE ENDS OF THE BASE, SAID SECOND TERMINAL DISPOSED IN ONE OF SAID END RECESSES, SAID MEANS EXTENDING AS SEPARATORS BETWEEN THE RESPECTIVE END RECESSES AND THE SEVERAL CONNECTING TABS TO ISOLATE THE TABS FROM THE SECOND TERMINAL.

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