Patent Publication Number: US-11043767-B2

Title: Method of forming an electrical terminal and an electrical terminal assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional application and claims the benefit under 35 U.S.C. § 120 of co-pending U.S. patent application Ser. No. 16/364,547, filed Mar. 26, 2019, the entire disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The invention generally relates to an electrical terminal. 
     BACKGROUND OF THE INVENTION 
     Electrical devices, such as heating elements or antenna elements, are often formed on or within the front or rear windows of a motor vehicle. In order to electrically connect the on-glass elements to electrical circuitry, such as a power supply or a radio receiver/transmitter, an electrical terminal, usually a male terminal, is soldered to the glass and is electrically connected with the electrical circuitry. A female terminal at the end of a cable connected to the power supply is then mated with the male terminal located on the glass. 
     In some applications, the male terminal has a male cylindrical post and the mating female terminal may have a cup shaped female socket having resilient contact tabs for engaging the cylindrical post. The contact tabs are bent inwardly into the socket for resilient engagement. The cup shaped socket of the female terminal is usually staked or riveted to a separate base piece which in turn is crimped to a conductor within the cable and housed within an insulative cover. The conductor may also be soldered directly to the cup shaped socket of the female terminal. 
     BRIEF SUMMARY OF THE INVENTION 
     According an embodiment of the invention, a method of forming an electrical connector assembly is provided. The method includes the step of stamping an electrical terminal preform from a sheet of metal. The electrical terminal preform has a base plate, a plurality of contact arms radially extending from the base plate, a wire attachment feature radially extending from the base plate and defining crimp wings, and a carrier strip. The method also includes the step of bending each of the plurality of contact arms to form a serpentine shape having a convex curve and a concave curve. The plurality of contact arms define a socket configured to receive a mating electrical terminal, thereby forming an electrical terminal. 
     An example embodiment having one or more features of the method of the previous paragraph further includes the step of bending a portion of the wire attachment feature to form a serpentine shape having a convex curve and a concave curve, wherein the portion of the wire attachment feature is one of the contact arms in the plurality of contact arms. 
     An example embodiment having one or more features of the method of the previous paragraph further includes the step of forming a first aperture in the base plate. 
     An example embodiment having one or more features of the method of the previous paragraph further includes the step of disposing the base plate and the plurality of contact arms within a cavity of a cover formed of dielectric material. 
     An example embodiment having one or more features of the method of the previous paragraph further includes the step of inserting a attachment stud extending from the cover through the first aperture in the base plate. The attachment stud has a flexible first tapered member extending outwardly from the attachment stud and tapered upwardly toward a cover cap of the cover. The first tapered member engages the base plate, thereby securing the cover to the base plate. 
     In an example embodiment having one or more features of the electrical connector assembly of the previous paragraph, the cover defines a second aperture in the cover cap axially aligned with the first aperture in the base plate. The method further includes the step of inserting the attachment stud through the second aperture in the cover cap. 
     In an example embodiment having one or more features of the electrical connector assembly of the previous paragraph, the mating electrical terminal has a generally cylindrical shape with a tapered outer sidewall. The mating electrical terminal defines a third aperture axially aligned with the first aperture in the base plate and the second aperture in the cover cap. The attachment stud has a pointed tip opposite the head. The attachment stud has a flexible second tapered member extending outwardly from the attachment stud and tapered upwardly away from the pointed tip of the attachment stud. The method further includes the steps of inserting the mating electrical terminal within the socket of the electrical terminal and inserting the attachment stud extends through the third aperture in the mating electrical terminal. The second tapered member engages the mating electrical terminal, thereby further securing the cover to the mating electrical terminal. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an electrical terminal according to one embodiment of the invention; 
         FIG. 2  is a top view of a sheet metal preform used to form the electrical terminal of  FIG. 1  according to one embodiment of the invention; 
         FIG. 3  is a perspective of an electrical connector assembly including the electrical terminal of  FIG. 1  according to one embodiment of the invention; 
         FIG. 4  is an exploded perspective view of the electrical connector assembly of  FIG. 3  according to one embodiment of the invention; 
         FIG. 5  is an exploded cross section view of the electrical connector assembly of  FIG. 3  according to one embodiment of the invention; 
         FIG. 6  is an partially assembled cross section view of the electrical connector assembly of  FIG. 3  according to one embodiment of the invention; 
         FIG. 7  is another partially assembled cross section view of the electrical connector assembly of  FIG. 3  according to one embodiment of the invention; 
         FIG. 8  is a cross section view of the electrical connector assembly of  FIG. 3  according to one embodiment of the invention; and 
         FIG. 9  is a flow chart of a method of forming an electrical connector assembly according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and networks have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. 
       FIG. 1  illustrates a non-limiting example of an electrical terminal according to one or more embodiments of the invention. The electrical terminal, hereinafter referred to as the terminal  10 , has a generally circular base plate  12  and a number of contact arms  14  extending from this base plate  12 . The contact arms  14  are arranged around a longitudinal axis X and are evenly spaced around the longitudinal axis X. In the illustrated example there are six contact arms  14  and the contact arms  14  are spaced approximately every 60 degrees around the longitudinal axis X. The contact arms  14  form a circular female socket  16  having an opening  18  that is configured to receive and engage a mating male post electrical terminal (see  FIG. 4 ), hereinafter referred to as the mating terminal  102 . The mating terminal  102  may be soldered to a metallic contact disposed on a glass surface of an automobile (not shown). The mating terminal  102  may be electrically connected to an electrical circuit on the glass surface, such as a defroster heating element or antenna element. 
     Alternative embodiments of the terminal may be envisioned that have as few as three or more than six contact arms. 
     Each contact arm  14  has a fixed end  22  attached to the base plate  12  and a free end  24  at a distal end of the contact arm  14 . Each contact arm  14  defines a convex curve  26  near the fixed end  22  and a concave curve  28  near the free end  24 , thereby forming a serpentine or S-shaped curve such that the free ends  24  of the contact arms  14  extend outwardly relative to the opening  18  to allow easy insertion and removal of the mating terminal  102  from the socket  16 . The distal edges of the base plate  12  are also rounded into a convex curve between the contact arms  14 . The terminal  10  also includes a wire attachment feature  30  that extends from of one of the contact arms  14 . The wire attachment feature  30  defines a pair or crimp wings  32  that are configured to mechanically and electrically attach the terminal  10  to a wire cable (not shown) that is electrically connected with electrical circuitry, e.g. circuitry associated with a radio receiver, radio transmitter, or defroster. As shown, the wire attachment feature  30  is longitudinally offset from the base plate  12 . The wire attachment feature  30  is also longitudinally offset from the free ends  24  of the contact arms  14 . 
     In alternative embodiments of the terminal, the wire attachment feature may further define a pair of insulation crimp wings (now shown) that are configured to attached to the insulation jacket of the wire cable. In addition or alternatively, the wire attachment feature may extend directly from the base plate rather than from one of the contact arms. 
     The terminal  10  is formed of a single piece of sheet metal material, such as a silver plated brass material. A flat terminal preform  34 , as shown in  FIG. 2 , is formed from the sheet metal material by a stamping or blanking process. Each terminal preform  34  is attached to a carrier strip  36  so that the terminal preforms  34  and the formed terminals  10  may be loaded onto a reel and automatically handled by terminal processing machines. The base plate  12 , contact arms  14 , and wire attachment feature  30  of the terminal preform  34  are then bent in a stamping and bending process by a forming die (not shown) having a series of forming steps into the desired shape of the terminal  10  shown in  FIG. 1 . 
       FIGS. 3 and 4  illustrate a non-limiting example of an electrical connector assembly, hereinafter referred to as the connector assembly  100 , that includes the terminal  10  described above. In addition to the terminal  10 , the connector assembly  100  further includes the mating terminal  102  which is configured to be received within the socket  16  formed by the terminal  10 . The mating terminal  102  has a generally cylindrical post shape with a tapered or flared outer sidewall  104 . The sidewall  104  tapers outwardly from near the base  106  of the mating terminal  102  to the end  108  of the mating terminal  102  received within the socket  16 , such that a portion of the sidewall  104  has a diameter that is less than the end  108  of the mating terminal  102 . In the illustrated example the mating terminal  102  may be characterized as having a concave outer sidewall  104 . 
     The connector assembly  100  further includes a cover  110  that is formed of a dielectric polymer material. The cover  110  defines a cavity  112  in which the base plate  12  and the plurality of contact arms  14  are received and from which the wire attachment feature  30  extends. 
     The cover  110  is secured to the terminal  10  and the mating terminal  102  by an attachment stud, hereinafter referred to as the stud  114 . The stud  114  has a flattened head  116  on one end and a pointed tip  118  on the other. The stud  114  has a flexible first tapered member  120 , in the illustrated example a flexible first tapered diaphragm encircling the shaft of the stud  114  and tapered upwardly toward the head  116  of the stud  114 . The stud  114  also has a flexible second tapered member  122 , in the illustrated example a flexible second tapered diaphragm encircling the shaft of the stud  114  and tapered upwardly away from the tip  118  of the stud  114 . The material forming the stud  114  is also a dielectric polymer material. 
       FIGS. 6 through 8  show a process of assembling the connector assembly  100 . As shown in  FIG. 6 , the terminal  10  is first attached to the mating terminal  102 . Since the diameter of the opening  18  of the socket  16  of the terminal  10  is less than the minimum diameter of the mating terminal  102 , the contact arms  14  flex outwardly as the concave curved portion of the contact arms  14  contact the end  108  of the mating terminal  102 . The terminal  10  then snaps in place as the contact arms  14  move down the mating terminal  102  to the tapered portion that has a smaller diameter than the end  108  of the mating terminal  102 , thereby mechanically connecting the terminal  10  to the mating terminal  102 . The inner apex surfaces of the concave curved portion of the contact arms  14  are in compressive contact with the mating terminal  102 , thereby providing a robust electrical connection between the terminal  10  and the mating terminal  102 . 
     As shown in  FIG. 7 , the base plate  12  and the plurality of contact arms  14  are placed within the cavity  112  of the cover  110 . 
     The base plate  12  of the terminal  10  defines a circular terminal aperture  40  extending therethrough. Likewise, a cover cap  124  of the cover  110  defines a circular cover aperture  126  extending therethrough and the mating terminal  102  also defines a circular mating terminal aperture  128  extending therethrough. The terminal  10  aperture, the cover aperture  126 , and the mating terminal  102  aperture are longitudinally aligned and are substantially coaxial with one another. The terminal aperture  40  has a larger diameter than the mating terminal aperture  128  and the cover aperture  126  has a larger diameter than the terminal aperture  40 . 
     As shown in  FIG. 8 , the stud  114  extends through the cover aperture  126 . Since the diameter of the head  116  of the stud  114  is larger than the cover aperture  126 , the head  116  cannot pass through the cover aperture  126 . The stud  114  also extends through the terminal aperture  40  in the base plate  12 . As the first tapered member  120  is pushed through the terminal aperture  40 , it flexes inwardly and then spring back once through the terminal aperture  40 . The first tapered member  120  then engages the inner surface of the base plate  12 . The first tapered member  120  and the head  116  cooperate to secure the cover  110  to the terminal  10 . The stud  114  further extends through the mating terminal aperture  128 . As the second tapered member  122  is pushed through the mating terminal aperture  128 , it flexes inwardly and then spring back once through the mating terminal aperture  128 . The second tapered member  122  then engages the bottom surface of the base plate  12 . The second tapered member  122  and the head  116  cooperate to secure the cover  110  to the mating terminal  102  and secure the terminal  10  to the mating terminal  102 . 
     In alternative embodiments of the connector assembly, the attachment stud may be formed by the cover cap and extends from the bottom of the cover cap. In other alternative embodiments, the first and second flexible members may be tapered fingers extending from the shaft of the stud, such as those found on “Christmas tree” fasteners commonly used in the automotive industry. 
       FIG. 9  illustrates a method  200  of forming the connector assembly  100 . The method  200  includes the following steps: 
     STEP  202 , STAMP AN ELECTRICAL TERMINAL PREFORM FROM A SHEET OF METAL, includes stamping the terminal preform  34  from a sheet of metal. The terminal preform  34  has a base plate  12 , a plurality of contact arms  14  radially extending from the base plate  12 , a wire attachment feature  30  radially extending from the base plate  12  and defining crimp wings  32 , and a carrier strip  36 ; 
     STEP  204 , BEND EACH OF THE PLURALITY OF CONTACT ARMS TO FORM A SOCKET, includes bending each of the plurality of contact arms  14  to form a socket  16  configured to receive the mating terminal  102 ; 
     STEP  206 , BEND A PORTION OF THE WIRE ATTACHMENT FEATURE TO FORM A CONTACT ARM, includes bending a portion of the wire attachment feature  30  to form one of the contact arms  14  in the plurality of contact arms  14 ; 
     STEP  208 , FORM A FIRST APERTURE IN THE BASE PLATE, includes forming the terminal aperture  40  in the base plate  12 ; 
     STEP  210 , DISPOSE THE BASE PLATE AND THE PLURALITY OF CONTACT ARMS WITHIN A CAVITY OF A COVER FORMED OF DIELECTRIC MATERIAL, includes disposing the base plate  12  and the plurality of contact arms  14  within a cavity  112  of a cover  110  formed of dielectric material; 
     STEP  212 , INSERT A MOUNTING STUD EXTENDING FROM THE COVER THROUGH THE FIRST APERTURE IN THE BASE PLATE, includes inserting the stud  114  extending from the cover  110  through the terminal aperture  40  in the base plate  12 . The stud  114  has a flexible first tapered member  120  extending outwardly from the stud  114  and tapered upwardly toward a cover cap  124  of the cover  110 . The first tapered member  120  engages the base plate  12 , thereby securing the cover  110  to the base plate  12 ; 
     STEP  214 , INSERT THE MOUNTING STUD THROUGH THE SECOND APERTURE IN THE COVER CAP, includes inserting the stud  114  through the cover aperture  126  in the cover cap  124 . The cover  110  defines the cover aperture  126  in the cover cap  124  which is axially aligned with the terminal aperture  40  in the base plate  12 ; 
     STEP  216 , INSERT THE MATING ELECTRICAL TERMINAL WITHIN THE SOCKET OF THE ELECTRICAL TERMINAL, inserting the mating terminal  102  within the socket  16  of the terminal  10 . The mating terminal  102  has a generally cylindrical shape with a tapered outer sidewall  104 . The mating terminal  102  defines a mating terminal aperture  128  axially aligned with the terminal aperture  40  in the base plate  12  and the cover aperture  126  in the cover cap  124 ; and 
     STEP  218 , INSERT THE MOUNTING STUD THROUGH THE THIRD APERTURE IN THE MATING ELECTRICAL TERMINAL, includes inserting the stud  114  extends through the mating terminal aperture  128  in the mating terminal  102 . The stud  114  has a pointed tip  118  opposite the head  116 . The stud  114  has a flexible second tapered member  122  extending outwardly from the stud  114  and tapered upwardly away from the pointed tip  118  of the stud  114 . The second tapered member  122  engages the mating terminal  102 , thereby further securing the cover  110  to the mating terminal  102 . 
     Accordingly, an electrical terminal  10 , an electrical connector assembly  100 , and a method  200  of forming the electrical terminal  10  and the electrical connector assembly  100  is provided. The method  200  produces a one-piece terminal  10  that provides the benefits of lower manufacturing costs and a simpler manufacturing process compared to similar prior art female terminals. The terminal  10  is also more robust and reliable and has improved electrical resistance characteristics compared to the prior art two piece terminals. The design of the terminal  10  allows a more compact cover  110 , thereby providing the benefit of reduced material usage and cost for forming the cover  110  and the reduced size of the cover  110  provides a connector assembly  100  that can more easily be packaged in a vehicle. Additionally, the stud  114  provides the benefit of not only attaching the cover  110  to the terminal  10  but also attaching the terminal  10  to the mating terminal  102 . 
     While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to configure a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely prototypical embodiments. 
     Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the following claims, along with the full scope of equivalents to which such claims are entitled. 
     As used herein, ‘one or more’ includes a function being performed by one element, a function being performed by more than one element, e.g., in a distributed fashion, several functions being performed by one element, several functions being performed by several elements, or any combination of the above. 
     It will also be understood that, although the terms first, second, etc. are, in some instances, used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first contact could be termed a second contact, and, similarly, a second contact could be termed a first contact, without departing from the scope of the various described embodiments. The first contact and the second contact are both contacts, but they are not the same contact. 
     The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various described embodiments and the appended claims, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term “and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     As used herein, the term “if” is, optionally, construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” depending on the context. Similarly, the phrase “if it is determined” or “if [a stated condition or event] is detected” is, optionally, construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event],” depending on the context. 
     Additionally, while terms of ordinance or orientation may be used herein these elements should not be limited by these terms. All terms of ordinance or orientation, unless stated otherwise, are used for purposes distinguishing one element from another, and do not denote any particular order, order of operations, direction or orientation unless stated otherwise.