US 2952831 A
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Sept. 13, 1960 M. EHRLICH CONTACT AND PRESSURE-LOCK TERMINAL Filed July 18, 1957 INVENTOR MA X/M/L m/v Ema ICH am /51% fl ATTO RN EYS United States PatentfQ CONTACT AND PRESSURE-LOCK TERMINAL Maximilian Ehrlich, Baldwin, N.Y., assignor to Leviton Manufacturing Co., Inc., Brooklyn, N.Y., a corporation of New York Filed July 18, 1957, Ser. No. 672,628
6 Claims. (Cl. 339-95) 4, 2,952,831 Patented Sept. ,13, 1961 F ice contact blade of an attachment plug (not shown) to be inserted therebetween and the resilience of the mate- 2,705,785 dated April 5, 1955. An object of the invenv tion is to simplify the construction of such a terminal and thereby to reduce manufacturing costs for a wiring device in which such a terminal is employed.
In a contact and pressure-lock terminal made in accordance with the present invention, the wire-engaging members, the terminal portions and the contact elements are permanently connected to each other,'being formed integrally from the same stock and separate members of special shape or difierent materials, such as. spring steel, are not required. Such an arrangement reduces the cost of forming the contact and terminal and of assembly.
Other advantages and objects of the invention will be apparent and best understood from the accompanying drawings in which: v
Fig. 1 is a top plan view of a duplex plug receptacle having a portion of its cover broken away and which embodies the invention; v
Fig. 2 is a section view taken along the line 2-2 of Fig. 1;
Fig. 3 is a top plan view of a contact and terminal strip embodying the invention; V
Fig. 4 is a side elevation of the contact and terminal strip shown in Fig. 3;
, Fig. 5 is an end view of the contact andjterminal strip shown in Fig. 3;
Fig. 6 is a section view taken along the line 6-6 of Fig. 3; and
Fig. 7 is a plan View of a blank from which the contact and terminal strip shown in Fig. 3 is formed.
' Referring to the drawings in'detaiLand toFig. 1 in particular, there is a duplex wiring receptacle 10 which includesa hollow base 11, a cover 12 and a supporting strap 13 which are held together in the usual manner by rivets or screws (not shown). V v The base 11 of the receptacle has a raised central boss 14 which extends lengthwise on the interior thereof. The boss 14 inconju'nction with a mating boss 15 on the lower surface of the cover divides the receptacle into two chambers, each of which contains a contact and terminal strip 16. The supporting strap 13 extends through a groove in the boss 15 on the cover and projects beyond the receptacle at the ends thereof.
As is shown best in Figs. 3 through 7, the contact and terminal strip 16 is formed from a blank of electrically conductive material, such as brass or the like. A set of opposing spring contact elements or fingers 17 are formed at each end of a central portion 18 by bending the ends of the blank to bring the fingers of each set of contact elements into opposing relation. The tops of the contact elements of each set are flared outwardly to permit a rial from which the blank is formed causes the contact elements to engage with the contact blade with a spring action.
The central portion 18 of the strip which serves as a terminal for connecting a conductor wire to the strip, is disposed in a vertical plane and has wire-guiding grooves 19 formed at the ends thereof adjacent each set of contact elements. A supporting leg 20 is bent up wardly from the lower edge of the central portion of the strip at the center thereof and extends inwardly therefrom.
Arms 21 are connected to the supporting leg at the outer end thereof and extend from each'side of the leg lengthwise of the central portion of the strip to a point beyond the Wire-guiding grooves formed therein. The arms extend outwardly and downwardly from the leg in a transverse direction and are disposed in angular relation to the plane of the central portion of the strip. When the contact and terminal strip 16 'is assembled in the base of the receptacle, the outer side of the central portion of the strip bears against an outer side wall of the base with the lower edges of the arms abutting the central boss at the point where it joins the bottom of the base.
A wire-engaging member 22 is connected to the top of each of the arms at the outer end thereof. The wireengaging members extend lengthwise in opposing relation to the central or terminal portion of the strip and the wire-receiving grooves therein. The wire-engaging members also extend upwardly and inwardly, from the arms in a transverse direction and are disposed in angular relation to the terminal portion of the strip,ywith the angle of the wire-engaging members relative to the terminal portion of the strip being somewhat greater than the angle of the arms relative to the terminal portion. The lower corner of the top of thewire-engaging member forms a sharp edge 23 which engages with the bared end of a conductor wire when the wire is inserted in one of the wire-guiding grooves between the terminal portion and the wire-engaging member. The edge of the wire-engaging member is spaced from the terminal portion by a distance slightly less than the diameter of the smallest conductor wire that is to be connected to the receptacle so that the spring pressure of the Wire-engaging-member will hold the wire firmly against the terminal portion and in good electrical contact therewith. .The flexing ofthe wire-engaging member will also allow larger diameter wires to be inserted within limits.
The bottom of the base is provided with wire-receiving openings 24 which are aligned with the wire-guiding grooves in the terminal portions of the strips so that the bared end of the conductor wire can be inserted through the. base and between the wire-engaging member and the terminal portions of the respective strips therein. Adjacent each of the wire insertion openings, elongated openings 25 are provided in the base through, which a tool maybe inserted to engage with the. wire-engaging member to release it fromengagement with the conductor wire.
The cover of the receptacle is provided with the usual pairs of spaced openings 26 through which the contact blades of an attachment plug may be inserted into engagement with the contact elements on two of the strips in the customary manner.
A blank suitable for forming the contact and terminal strips 16 is shown in Fig. 7. The blank may be stamped from a flat strip of the conductive metal and then be shaped to the desired configuration by suitable forming dies. The metals usually used for forming contact and terminal strips will provide sufiicient spring action for the functioning of the wire-engaging members as described above. Thus, the, spring action of the wireengaging members isobtainedwithoutthe use ofseparate parts made from special material, such as spring ,"steeli,
When the bared end'of aconductor'wire' isinserted through-tone. ofthetopenings inthe base and between. the wire-engaging member and terminal portion of the strip,
the wire-engaging member flexes upwardly to permit" entry of the wire and'the barediend of the wire is forced, against the terminal portion of the strip by the wire engaging member, as described: above. However, if a downward pull is exertedon the wire, the sharp corner of the wire engaging member bites into the wire and preventswithdrawal 'of the wire. fThe downward pull on the wire tends to bend theend of the wire-engaging member downwardly and toward the terminal portion of the strip, withrthe result that the wire is clamped more tightly between the wire-engaging member and the terininal portion of thestrip; 'Such bending of the wire engaging member is resisted bythe arms which are in engagement with the boss in the base. In addition, the engagement of the arms with the boss in the base tends to minimize distortion or twisting of the wire-engaging members by repeated insertion of a wire or releasing tools through the openingsin the base. 7 l V i It will be understood that various changes and modifications may be made-in the particular embodiment of the invention illustrated and described herein without departing from the scope of the following claims,
I claim: 7 1 i 1. In a combined contact and pressure-lock terminal for an electrical wiring device, the improvement which comprisesastrip of electrically conductive material, said strip including a terminal portion having a flat face with a wire-guiding groove formed therein, said groove ex: tendingtransversely across said face 'of. the terminal 4. In a combined contact andpressure-lock terminal for an electrical wiring device, the improvement which comprises a strip of electrically conductive material, said strip including a terminal portion having a flat face and wire-guiding grooves formed at the ends of said face, said grooves extending transversely across the face of said terminal portion, a leg' integrally connected to the terminal portion at'a point intermediate the grooves, said leg extending from the terminal portion in angular relation' to the flat face thereof and having an end spaced from said face, arms integrally connected to 'said end of the leg and extending lengthwise in opposite directions therefrom in opposing relation to the terminal portion,
said arms also extending outwardly and downwardly from said leg in a transverse direction and being disposed at an angle with respect to the face of the terminal portion and a wire-engaging member integrally connected to each of said arms, each of said wire-engaging members'extending toward the face of the terminal portion in opposing relation to one for the wire-guiding grooves and being disposed at an angle of less than ninety degrees with'resp'ect to the face of the terminal portion, said wire-engaging members having ends spaced from the face of the terminal portion by a distance less than thediamportion, a leg integrally connected to the terminal ,por-
tion at a point spacedfrom said groove, said leg extending from the terminal portion in angular relation to the flat face thereof and having an end' spaced from said face, an arm integrally connected to said end of the leg and extending lengthwise therefrom in opposing relation to the face of the terminal portion, said arm also extending outwardly and downwardly fromsaid leg in a transverse direction and being disposed at an-angleqivith respect to the face of the terminal portion and awire:
engaging member integrally connected to the .arm and extending toward the face of the terminal portion in opposing relation to thewire-guiding groove, said'wire: engaging member being disposed at an angle'of'less than ninety degrees with respect to the face of the terminal portion and having an edge spaced'from the face of the terminal portion by a distance less than the diameter of a bare conductor wire. V r
' 2. In a-combinedcontact and pressure-lock terminal, the improvement as'defined in claim l wherein the wire.-
engaging member and the arm are disposedat difierent angles with respect to the face of the terminal portion. 3. In a combined contact and pressure-locktterminal for an electrical wiring device, the improvement .asdefined in claim 1 which includes a pair of spaced spring contact fingers integrally connected to the terminal portion of the strip adjacent the wire-guiding groove.
eter of a bare connector wire. 7
5.- In a combined contact and pressure-lock terminal for an electrical wiring device, theimprovement as defined in claim 4 wherein the wire-engaging members and the arm are disposed at'diflerent angles with respect to the face of the terminal portion. 7
6.. In'anelectrical wiring device of the character described, the improvement whichcomprises a housing of insulating material having a recess formed therein, said recess being defined on one side by an upstanding wall and on the. otherfside by an abutment spaced from and opposing said wall,'a combined contact and pressure lock terminal formed from a single strip of electrically conductive material locatedv in said recess, said stripincluding a'terminal portion having a flat face with a wireguiding groove formed therein, said terminal portion being disposed against theiupstanding' wall on one side of, the recess with the wire-guiding groove, being aligned with a.wire-receiving opening inthe housing, a leg extending inwardly from the terminal portion of the strip and toward the other side of the recess, an arm carried by the leg and extending lengthwise therefrom in opposing relation to the terminal portion of the strip, said arm also extending outwardly and downwardly from the'leg in angular relation to the terminal portion of the'strip and engaging with the abutment at the other-side of the ofthe strip.
References Citediin the file of this patent UNITED STATES PATENTS 2,705,785 Benander Apr. 5,]1955 12,720,634 'Hart Oct. 11, 1955 2,773,248 Smith Dec. 4, '1956 1a can,