US2193008A - Switch terminal - Google Patents

Description

March 12, 1940. G. o. PUERNER SWITCH TERMINAL Filed Sept. 1, 1937 2 Sheets-Sheet l INVENTOR figqgz 0 P4107267 ATTORN EY March 12, 1940. G. o. PUERNER 2,193,003

SWITCH TERMINAL Filed Sept. 1, 1957 2 Sheets-Sheet 2 1 m!!! f H IHHH Ii l INVENTOR fiwgge 0 Parr/2a" ATTORNEY Patented Mar. 12, W49

AIKEN? swrron TERMINAL George 0. Puerncn'indianapolis, ma, assignor to P. R. Mallory & 00., Inc., Indianapolis, Ind, a

corporationoi' Delaware Application September 1, 1937, Serial No. 151,941

13 Claims,

This invention relatesto electric switch terminals.

[An object of theinvention is to provide an improved contact terminal for electric switches.

Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the appended claims. I

The invention comprises the features of construction, combination of elements, arrangement of parts, and methods of manufacture and operation referred to above or which will be brought out and exemplified in the disclosure hereinafter set forth, including the illustrations in the draw ings.

In the drawings: g Figure 1 is a perspective view of a switch terminal embodying features of the present invention;

Figure 2 is a perspective view of a modified terminal member;

Figure 3 is the face View of an electric switch; Figure 4 is a section on the line 4- 1 of Figure 3;

Figure 5 is a face View of another form of electric switch;

Figure 6 is a section on the line 6+6 of Figure 5.

Figure '1 shows a further modified form of switch terminal;

Figure Sis a face view thereof;

Figure 9 shows an electric switch embodying said contacts; and

Figure 10 is a section on the line Hi-I0 of Figure 9. v

A feature of the present invention resides in a novel contact terminal design embodying coopcrating terminal fingers integrally formed from a single piece of sheet metal.-

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the meth- 0d of procedure and the construction of parts without departing from the spirit of the invention. In the following description and in the claims, parts will be identified by specific names for convenience but they are intended to be as generic in their application to similar parts as the art will permit. I a

In electric switches or" the type used in radio sets and similar equipment, such as for changing the connection of inductance coils and condensers it is of paramount importance'that the switches operate with ease and still provide positive action anad provide perfect low resistance contact at all times. It is also a requisite that the terminals have the necessary electrical characteristics for use with high frequency and ultra high frequency radio currents.

Contact terminals have been made in the past in which a single contactsurface was provided to cooperate with a moveable contactmember and contacts have also been provided having a pair of cooperating fingers adapted to receive the moving contact member between them. The latter type of contact is sometimes of advantage since the two cooperating contact areas insure that perfect electrical connection will be made under all circumstances. However, in the past difiiculty has frequently been experienced in providing a contact terminal wherein the two coopcrating surfaces were accurately spaced and remained in perfectacljustmentwith subsequent use and abuse. It has been a frequent experience to find one of the contacting portions bent out of alignment with the other. This frequently occurs during theoperation' of securing and soldering wires to the soldering terminals of the contact. l

The contact of the present invention overcomes these difiiculties and others and is more economi-- In these operations the elongate thin,.flat strip of metal it; is given the form shown in Fig- .ure 1 comprising a central body portion H having a punchedhole lg'for securing the contact terminal to the switch base, At one end of portion 52 the strip iii is bent to provide a shallow U-shaped portion l3 which. aids in positioning the terminal on the switch base as will be'further described. the outer edge of the U-shaped portion l3 and is provided with an elongate opening l5 which aids insecuring and soldering a wire thereto. Soldering lug it provides a convenient means for securing the circuit wires. to the switch terminal.

The opposite end of strip iii adjacent to central table portionli'is punched to provide a A soldering lug Hi extends from tongue it framed by a closed loop formed of arms El and It being joined by a cross portion 7 9 at their outer ends. The tongue is is bent down at a slight angle with the plane of table portion II and is formed at its end into a convex rounded contact surface 20. Arms H and it are bent into upwardly rounded arches whereby cross portion l9 is retracted to a position immediately facing the convex contact surface 28 of tongue l6. Cross portions I9 is formed into a convex rounded face opposing contact face 20.

The terminals Hi may be secured to a switch base 2! of sheet insulation, such as sheet Bakelite, by means of rivets 22 passing through holes l2 in the terminals. The base 2| may be provided with edge notches 23 into which the U- shaped portions E3 of the terminals fit to secure the terminals against turning. Terminal lugs l4 extend beyond the edge of the base to provide circuit connections. Rectangular apertures 24 are provided in the switch base, directly behind the contact tongues Hi to allow them to spring back when the rotor contact engages them. However, the switch base engages each tongue is near its base and thereby straightens it into a plane flush with the face of the switch base. This also operates to bring contact face 20 into contact with face is subject to being temporarily spread apart by the rotor contact when it engages a particular contact H) in the operation of the switch.

The switch rotor may be mounted to turn in a bushing 25 secured in an aperture in the switch base and may comprise a rotor shaft 25 passing through bushing 25, to the end of which the rotor contact arm 27 is secured by upsetting the end of the shaft.

Rotor contact arm 21 extends in a direction transverse of the shaft axis and terminates at one end in a flat contact portion 28 adapted to travel in a path between contact faces l9 and 2!! of the stator contacts upon rotation of shaft 25. The contact portion 28, upon engaging any stator contact In, separates contact faces |9 and 2c sufficient for the rotor contact portion 28 to enter between them and make electrical contact with both.

The opposite end'of rotor contact arm 2'! has material removed from the body thereof to rovide a central slot between two side arms and is bent to provide a U-shaped portion 29. The free end of the contact arm, beyond the U-shaped portion, extends down along the side of bushing 25. Bushing25 is at this place, provided with. an-integral rim 3B in which a series of teeth 3| are cut. The end of contact arm 2'! rests against the toothed portion of rim 3B and is pro:

vided with an indexing projection 32 which, in co-operation with'the teeth, provides an index means for the rotor contact so that it may be set on any stator contact desired.

Figure 2 shows a modified switch contact terminal 40 having another means for mounting on a switch base. The portions 44, 45, 46, 61, til, 49 and 50 are similar to the portions l4, l5, l6. l1, l8, l9 and 20 respectively of contact terminal H3. The difierence resides in the mounting means which here comprises a U-shaped loop 43 formed in the mid-portion of the contact terminal. The middle of the loop is cut to provide a narrowed portion 4| adapted to be crimped to secure the contact terminal to the switch base.

The mounting of terminals 40 in a switch is shown in Figures 5 and 6. The switch base 5| of sheet insulation is provided with a number of H-shaped apertures 53 inc each of which the U-shaped portion 43 fits. The shoulders 12 will then be substantially flush with the back surface of switch base 5| Narowed portion 4| may be crimped as shown to secure the terminal to the base.

The remainder of the switch is generally similar to the one previously described but in this switch the rotor contact arm 51. is provided with two contact shoe portions 58 which make contact with two stator contacts simultaneously or in any sequence desired.

The modified switch terminal shown in Figures 7, 8, 9 and 10 embodies similar ideas of construction to the terminals already described and in addition is so formed as to enable two such switch terminals to be mounted on opposite faces of a switch base and still occupy the same switch position.

Terminal: Til comprises a central body portion formed into a loop ll for mounting the terminal in substantially the same manner as terminal 40 is mounted. A soldering lug 12 extends outwardly in one direction from loop portion 1| and the contacting portions 13 and 14 extend in the other direction from the loop 1|. Contacting portions 13 and M are generally similar to the contact tongue previously described. Portion -13 differs, however, in that its free end is bent in the manner shown to provide a cutting edge contact; This contact portion is thus adapted to make a very positive contact with the cooperating contact shoe which slides between the two contact portions in operation of the switch, contact portion it being adapted to cut through any dirt or tarnish on the contacting surfaces and make positive metal-to-metal contact. Contacting portion M, on the other hand, is of the same form as previously described and not only serves as an additional contact but also helps in keeping the contacting shoe in engagement with contact portion '23.

An important feature of this modification is best illustrated in Figure 9. It will be noted that p the central portion ll of terminal 10 is not'disposed on a straight line'drawn through the two ends of the terminal but is laterally offset therefrom. It is therefore possible, as shown inFigure 9 to mount one terminal 10a in one'mounting hole in stator 15 and to mount another similar terminal lllb on the opposite face of stator disc ill in another mounting hole so that the two terminals are efiectively isolated from each other. Because of the offset relation, however, the soldering lugs 12a and 12b are situated inthe same terminal position. The active contact terminals 13a, "Ma and 131), Mb are also positioned in the same contact position on the two opposite sides of the stator. It will be evident that contact terminal We may be arranged to make contact with one rotor contact shoe 11 mounted on one face of rotor i6 and that contact 19b will cooperate with rotor shoe 18 mounted on the other face of the rotor substantially as shown in Figures 9 and 10. I-Ieretofore, when it was desired to mount two terminals in the same switch position on opposite sides of the stator disc additional insulating means have been necessary to keep the two terminals insulated from each other.

It will be noted that the terminal as formed allows'ample space betweenthe contact faces for silver plating to be deposited on the contacting surfaces.

Another advantage of this type of switch resides in the fact that the wire-securing lug may be bent at any angle without disturbing the alignment, positioning or spring tension on the contact fingers.

There is also obtained an increased length of spring arm due to the shape of the spring arms and the spring action is also improved by the bifurcated nature of the spring arm.

While the present invention, as to its objects and advantages, has been described herein as carried out in specific embodiments thereof, itis not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed is:

1. A contact terminal for electric switches comprising a single strip of sheet metal having one end ptuiched to form a tongue and a continuous metal border surrounding said tongue, the parts being bent in relation to each other to provide opposed contact surfaces adapted to engage directly opposed portions on opposite faces of a contact inserted between said surfaces, one of said surfaces being the end of said tongue and the other of said surfaces being the cross-portion of said border formed. of material originally beyond the end ofsaid tongue.

2. A contact terminal comprising a piece of sheet metal formed into a securing portion, a tongue extending therefrom, a pair of arms secured thereto at the two sides of the base of said tongue and formed into corresponding arches at the two sides of said tongue, said arms being joined at their ends by a bridging portion disposed in opposed. relation to the end of said tongue, whereby said tongue end and said bridging portion form opposed contact surfaces adapted to engage directly opposed portions on opposite faces of a contact inserted between said surfaces.

3. A contact terminal formed of a strip of sheet metal and comprising a central mounting portion of a single thickness of said sheet metal having means for securing said contact terminal to a switch base, a wire-securing terminal at one side of said mounting portion and a .pair of contact fingers at the opposite side of said mounting portion, both of said fingers being integrally attached to said single thickness mounting portion and having contact faces at their ends disposed in opposed face-to-face relation to each other, whereby said contact faces are adapted to engage directly opposed portions on opposite faces of a contact shoe inserted between said faces.

4. A contact terminal formed of a strip of sheet metal and comprising a central mounting portion having means for securing said contact terminal to a switch base, a "wire securing terminal at one side of said mounting portion and a pair of contact fingers at the opposite side of said mounting portion, both of said fingers being integrally attached to said mounting portion and having contact faces at their ends disposed in directly opposed face-to-face relation to each other whereby said contact faces are adapted to engage directly opposed portions on opposite faces of a contact faces, one of said fingers comprising a frame of metal derived from the region bordering said other finger.

5. A contact terminal formed of a strip of sheet metal and comprising a central mounting portion having means for securing said contact terminal to a switch base, a wire-securing terminal at one side of said mounting portion and a projecting area on the opposite side of said mounting portion, said projecting area being punched to form a tongue and a continuous metal border surrounding said tongue, the parts shoe inserted between said being bent in relation to each other to provide directly opposed contact surfaces adapted to engage directly opposed portions on opposite faces of a contact inserted between said surfaces, one of said surfaces being the end of said tongue and the other of said surfaces being the cross-portion of said border formed of material originally beyond the end of said tongue.

6. A contact for electric switches comprising a pair of contact tongues of sheet metal arranged the edge of said frame-shaped tongue comprising its contacting surface.

8. A contact terminal for electric switches comprising a single strip of sheet metal having at one end thereof a pair of contact tongues, one of said tongues comprising a frame formed of the metal surrounding the other of said tongues, the

edge of said frame-shaped tongue comprising its contacting surface and the face of said other tongue comprising its contacting surface, the edge contacting surface of tongue being opposite to the contact face of said other tongue.

9. An electric switch comprising a stator of said frame shaped sheet insulating material, an aperture therein,

a bushing secured in said aperture, said bushing having an integral flange thereon, stator contacts mounted on said stator, and a rotor comprising a shaft pivoted in said bushing and a rotor arm secured to the end thereof, said rotor arm having at least one contacting portion engaging said stator contacts and an indexing arm, said flange on said bushing having indexing inundations around at least a portion of its periphery and said indexing arm having a projection engaging said inundations.

10. A contact terminal for electric switches comprising a strip of sheet metal having a central mounting portion, a: wire securing tongue at one end and a contacting; portion at the other end thereof, said central mounting portion being laterally offset to one side of a line through the two ends of said strip whereby said central.

mounting portion may be secured to a stator plate in a position different from the position occupied by the wire securing tongue and the contacting portion. I

11. A switch stator assembly comprising a stator of sheet insulating material and a pair of stator contacts secured on opposite faces thereof, said contacts comprising elongated sheet metal members each having a wire securing portion I at one end thereof, a contacting portion at the other end thereof and an attaching portion at intermediate point thereof; said intermediate point being laterally offset to one side of a line through the two ends of said member, the wire securing portions and contacting portions of both of said members occupying a single stator posi tion, the attaching portions occupying positions offset respectively to the right and to left of said position.

12. A contact terminal for electric switches comprising a strip of sheet metal having a censaid contacts comprising elongated sheet metal members each having a wire securing portion at one end thereof, a contacting portion at the other end thereof and an attaching portion at an intermediate point thereof, said attaching portion and said contacting portion being angularly disposed in relation to each other, the contacting portions of both of said members occupying a single stator position, and the attaching portions occupying positions ofiset respectively to the right and to 10 the left of said position.

GEORGE O. PUERNER.

Images