US2550777A - Push-button electric switch - Google Patents

Description

May l, 1951 l H. E. COBB ETAL 2,550,777

PUSH-BUTTON ELECTRIC SWITCH Filed Oct. l2, 1949 :3o 8 E 37 i 36 F.rj

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Patented May 1, 1951 UNITED STATES PATENT OFFICE PUSH-BUTTON ELECTRIC SWITCH Application October 12, 1949, Serial No. 120,996

(Cl. o-16) 1 Claim.

Our invention relates in general to improvements in the art of controlling electric circuits, and relates more specifically to improvements in the construction and operation of push button electric switches or stations especially adapted to control the actuation of magnetic switches or the like.

The principal object of our present invention is to provide an improved push button switch assemblage which is simple, compact and durable in construction, and which is moreover highly eliicient in operation.

When operating magnetically actuated electric controls for motors or the like it is desirable to provide a starting and stopping auxiliary switch for the purpose of energizing and ole-energizing the magnet or magnets of the main switch. This auxiliary control unit is preferably of the pushbutton type located at a conveniently accessible location or station, and should embody two contact sets each comprising a iixed and a movable contact, one of which should be operable by a button to start the magnetic control while the other is operable to stop it. Such auxiliary control devices must be safely and reliably operable, and should also be compact in order to permit installation thereof Within or closely adjacent to the housing for the main control switch with which it cooperates.

It is therefore an important object of the present invention to provide an improved starting and stopping switch unit which is especially adapted for cooperation with magnetically actuated motor controllers or the like, and which embodies all of the above mentioned desirable features.

Another important object of this invention is to provide a dual push button station for controllers or the like, which may be installed in minimum space and utilized for diverse purposes.

A further object oi our invention is to provide an improved push button switch assemblage composed of few simple and sturdy parts, and wherein the electrical conductors are well insulated so as to insure maximum safety.

Still another object of the invention is to provide an improved starting and stopping electric switch of the push button type, which may be manufactured and sold at moderate cost and conveniently installed so that all parts thereof are subsequently readily accessible for manipulation or inspection.

An additional object of the present invention is to provide an improved double button switch unit in which various duplicate parts are interchangeably similar in construction, wherein most of the current conductors may be accurately produced from sheet metal with the aid of punches and dies, and in which the parts may be readily assembled.

These and other specific objects and advantages of our present invention should be apparent from the following description.

A clear idea of the various features constituting our invention, and of the construction and mode of utilizing a typical push button switch or station embodying the improvements, may be had by referring to the drawing accompanying and forming a part of this speciiication wherein like reference characters designate the same or similar parts in the several views.

Fig. l is a relatively large rear view of our improved push button switch unit removed from its housing and showing the two sets of fixed and movable contacts in elevation;

Fig. 2 is a central vertical section through the switch assembly of Fig. 1 taken along the line 2 2, but also showing the switch housing;

Fig. 3 is a reduced front elevation of the improved push button switch station, showing the assemblage in one actual commerical size;

Fig. 4 is a transverse section through the reduced assemblage, taken along the line 4-4 of Fig. 2; and

Fig. 5 is a fragmentary section through the same assembly, taken along the line 5--5 of Fig. 3.

Although we have illustrated and described our invenjon herein as being especially adapted for application to start and stop push button switches cooperating with magnetic controllers, it is not our desire or intent to unnecessarily limit the field of application thereof; and it is also contemplated that specific descriptive terms be given the broadest possible interpretation consistent with the disclosure.

Referring to the drawing, the typical improved push button switch or station shown therein, comprises in general a main unitary switch body B having therein a rear recess 9 and two segregated iront recesses it, il separated from the recess 9 by a transverse body portion l2; similar start and stop push buttons ld, le siidably confined within the recesses Il resrectively and each having an integral polygonal rear projection lc extending through and snugly slidable within a similarly polygonal hole in the body portion I2; similar movable contacts lly i9 `carried by the rear extremities of the projections l of the push buttons Iii, l5 respectively and being secured to their respective carrying projections by special screws I9; a similar coil spring 2t tending to constantly urge each of the push buttons I4, I5 and its movable contact ITI, I8 forwardly; iixed contact plates 22, 23, 24 secured within the rear body recess 9 by rivets 25, the plate 22 having a fixed starting Contact 26 `formed integral therewith and the plate 24 having a ixed stopping contact 2l formed integral therewith while the common plate 23 has both start and stop xed contacts 2li, 21 formed thereon; a cover 2Q to which the switch body 8 is secured by screws and a switch casing 3I with which the cover 29 is normally cooperable to enclose the fixed and movable switch contacts.

The main body 8 and the two similar push ybuttons I4, I5 are preferably formed of 'durable' and relatively hard insulating material, and the interior of the rear body recess S between the two sets of starting and stopping contacts is provided with a guard wall 33 formed integral with the body, as shown in Figs. 1 and 2. rfhe front face of the upper push button i4 may be colored green and provided with the word sc art, while the corresponding face of the lower button i5 may be colored'red and provided with the word Stop, as illustrated in Fig. 3. The rear of each of the buttons I4, I5 is provided with an annular groove within whichthe front portion of the ad jacent spring 2li is confined, and the rear ends of these springs 2li coact with insulating and rivet covering washers 34, as indicated in Fig. 2. This construction of the body 3, push button I4, I5, and springs 2li provides a very compact and well insulated buton assembly for actuating the movable contacts I'I, I8.

Each of thev movable contacts Il, I8 consists of a bronze metal washer secured to the square or otherwise polygonal projection I6 of its carrying button I4, I5 by means of a specially con structed screw I9k having threads terminating in notched ends adapted,v to' bite into anolvrmly grip the insulating material from which the buttons are formed. The fixed contact plates 22, 23, 24 which are firmly an'd'permanently secured to the body portion I2 by the rivets 25, are formed of metal stampings, and each of these plates 22, 23, 24 is provided with a terminal attaching screw `35 as depicted in Fig. l,- The rivets 25 are all alike and pierce the adjacent terminal plates and the bodyr portion I2, the heads of these rivets lying beneath the insulation washers 34 whilethe shanks thereof are riveted over the adjacent plates 22, 23, 24. The spaced stationary start contacts 26 lie in the common plane of the plates I 22, 23, and are engaged by thev movable contact I'I whenever the push button I4 is depressed to complete the electric circuit acrossv these plates 22, 23; but the spaced stationary stop` contacts 2l, are off-set from the common plane of the plates 23, 24 and are normally engaged by the other movable Contact IB to complete the'electric circuit across these plates 23, 24.

In order to permit the switch assembly to be readily removed from the normally xed casing 3l for the purpose of making the electrical connections, 0r for inspection purposes, the switch body 8 is rigidly attached to the removable cover 2S. Such firm attachment is effected by means of the two diagonally opposite screws 2l) the heads of which coact with lock washers 3G and with metal clamping plates 3l, while their Shanks have screw thread coaction with a metal reenforcing plate `38 permanently attached as by welding to the rear of the cover 2S, as shown in Figs. 1, 2, 4, and 5. The two clamping plates 3l are of similar formation and coact with a rear surface of the body 2, and these plates 31 may be stiiiened by integral flanges 40 as shown. `The front of the body 8 is provided with a shoulder 4I which coacts with the reinforcing plate 38 as in Figs. 2 and 5, so that rigid attachment of the bodt7 8 to the cover 2e is assured;

The switch housing or casing 3l and the cover 29 are formed of sheet metal, and the casing 3| may be attached to a support by screws coacting with openings 42 in its bottom as illustrated in Fig. 4. The casing SI is also provided with an opening 43 in one wall thereof for the electrical conductors which are attached to the terminal plates 22, 23, 24 by the terminal screws 35; and 'the interior of thel casing 3l has two diagonally opposite angular sheet metal brackets 44 lwelded. or'otherwise secured thereto, see Figs. 3 and 4. The cover 22 is readily detachably secured to these stilic brackets 44 by means of screws 45, thus making the switch mechanism quickly yand conveniently accessible while normally eiectively housing the same within the casing 3 i. The cas-- ing 3l, cover 22, brackets 44, plates 3l, 38, lixed or stationary terminal plates 22, 23, 24, and movable contacts ll, I8, may all be formed of suitable sheet metal with the aid of punches and dies; and various parts such as the contacts Il, I8, screws I9, springs 283, rivets 25, brackets 44, screws 30, washers 36, screws 45, and terminal screws 35,. are interchangeably similar thus facilitating mass production at minimum cost.

When the various parts of the switch unit have been properly constructed and assembled as above described the switch may be utilized for various purposes such as the control of a magnetic switch for motor starters. The stop contacts I8, 2l are normally closed thereby connecting the terminal plates 23, 24; and Iwhen the Start button I4 is depressed the contacts il, 26 will also be closed to complete the circuit through these terminal plates and the closed stop contacts. The magnetic switch will then complete the motor starting circuit which will remain thus completed until the Stop button I 5 is depressed to interrupt the coil circuit of the magnetic switch, whereupon the motor will be stopped until the Start button is again depressed. The push buttons I4, I5 will always be returned to their foremost positions as shown in Fig. 2, by the springs 2G, whenever the buttons are released, thereby opening or disengaging the startngcontacts Il, 26 and engaging the contacts i8, 2l; and the dual push button switch unit may be utilized under any conditions where such functioning of the two sets of contacts is desirable or necessary.

From the foregoing detailed description of the construction and operation of our improved push button switch, it will be apparent that we have in fact provided a dual switch assembly which is extremely simple, compact and durable in con-v struction and which is also conveniently manip-1 ulable and eili'cient in operation. All parts of the improved unit are normally well insulated and.' protected, but they are also readily accessible for installation and inspection, and present a highly aesthetic appearance. By forming most of the metallic parts with the aid of punches and dies, and by making numerous other partsI interchangeably similar, the cost of quantity production is greatly reduced and assembly is facilitated. The polygonal projections I6 of the push buttons I4, i5 eiectively guide these buttons while preventing rotation thereof, and the location of the,

springs within the rear button grooves enhances the compactness of the button assembly and also increases the available button guiding surface so that these buttons cannot tilt and jam. The formation of the body 8 with opposed front and rear recesses la, 9 and with a segregating web portion l2 therebetween and a dividing wall 33 between the switch contacts, provides a durable and well insulated support for the push buttons I4, I5 and for the electrical contacts and conductors, and by mounting the body 8 upon the cover 29 the switch may be quickly opened to expose its interior. The improved construction of the body 8 also permits the use of identical rivets 25 throughout, and these units can obviously be installed in very restricted spaces and for diverse uses.

t should 'ce understood that it is not desired to limit this invention to the exact details of construction, or to the precise mode of use of the typical dual push button switch unit herein shown and described, for various modifications within the scope of the appended claim may occur to persons skilled in the art.

We claim:

In a push button switch, a unitart7 body-of insulation having an integral transverse web penetra-ted by spaced polygonal openings and being provided on one side of the web with segregated cylindrical front recesses disposed coaxially of said openings and on the opposite side of the web 3 with a rear recess having therein a transverse wall formed integral with said web and disposed between said openings, a cylindrical push button of insulation slidably coni-ined within each front recess and having a rear polygonal projection slidable through the adjacent web opening and also having a rear annular groove facing said web, a helical compression spring seated in each of said grooves and coacting with said web t0 constantly urge the corresponding button forwardly within its confining front recess, an annular movable contact secured to the rear extremity of each of said polygonal projections and coacting with said web to limit the forward movement of said buttons to approximately the forward ends of their confining recesses, and Xed contacts secured to said body within said rear recess and being alternately cooperable 'with opposite faces of said movable contacts, one Set of said xed contacts spanning said wall and being common to both of said movable contacts.

HAROLD E. COBB. WILLIAM C. FURNAS.

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

UNITED STATES PATENTS Number Name- Date 1,993,135 Rees Mar. 28, 1933 1,996,891 Van Valkenburg Apr. 9, 1935 2,113,756 Bissell Apr. 12, 1938 2,422,097 Hansen June 10, 1947

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