Patent Publication Number: US-8992270-B2

Title: Electrical terminal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application No. 61/705,830 filed 26 Sep. 2012, which is hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to an electrical terminal. 
     BACKGROUND 
     Electrical terminals are known to have various configurations. Examples of electrical terminals are described in the following patents and patent applications: U.S. Pat. No. 5,334,058, U.S. Pat. No. 6,475,040, DE10019241, U.S. Pat. No. 5,755,599, U.S. Pat. No. 5,664,972, U.S. Pat. No. 4,040,713, U.S. Pat. No. 5,064,379, U.S. Pat. No. 5,147,230, U.S. Pat. No. 5,064,379, WO8905531, and US20090085712. With the increased use of round and square pins to make electrical connections—as opposed to flat blades—a need exists for an electrical terminal that can receive such pins, and which can handle the higher current loads found in many modern applications, as well as maintain required normal force over many insertions and removals of the mating pins. 
     SUMMARY 
     At least some embodiments of the invention include an electrical terminal including a contact portion having a contact portion base with a plurality of sides and forming a polyhedron structure. The contact portion further includes a plurality of contact arms, at least one of the contact arms extending from a respective one of at least two of the sides. The contact arms being arranged to receive a mating electrical component to contact each of the contact arms at a distal portion of the mating electrical component. A spring arrangement includes a spring base and a plurality of spring arms extending therefrom. Each of the spring arms contacts at least one of the contact arms near a distal end of the contact portion for applying a force thereto in a direction toward a central axis of the contact portion. The spring base is disposed toward a proximal end of the contact portion and includes an aperture for receiving the mating electrical component therethrough. The aperture is sized such that a proximal portion of the mating electrical component is supported by the spring base. 
     At least some embodiments of the invention include an electrical terminal including a contact portion having a contact portion base with a plurality of sides and forming a polyhedron structure having a central axis. The contact portion further includes a plurality of contact arms, at least one of the contact arms extending from a respective one of at least two of the sides. The contact arms are arranged to receive a mating electrical component to contact each of the contact arms at a distal portion of the mating electrical component. A spring arrangement includes a spring base disposed within the contact portion and toward a proximal end thereof. The spring arrangement further includes a plurality of spring arms extending therefrom, each of the spring arms contacting at least one of the contact arms near a distal end of the contact portion for applying a force thereto in a direction toward the central axis of the contact portion. The spring base includes a support structure for supporting a proximal portion of the mating electrical component. 
     At least some embodiments of the invention include an electrical terminal including a contact portion having a plurality of contact arms arranged to receive a mating electrical component and support the mating electrical component at a distal portion thereof. A spring arrangement includes a spring base disposed within the contact portion and toward a proximal end thereof. The spring base includes a support structure for supporting a proximal portion of the mating electrical component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of an electrical terminal in accordance with an embodiment of the present invention; 
         FIG. 2  shows a fragmentary view of the electrical terminal from  FIG. 1  with a mating electrical component in the form of a round pin; 
         FIG. 3  shows a perspective view of an electrical terminal in accordance with an embodiment of the present invention; 
         FIG. 4  shows a fragmentary view of the electrical terminal from  FIG. 3  with a mating electrical component in the form of a round pin; 
         FIG. 5  shows a perspective view of an electrical terminal in accordance with an embodiment of the present invention having a proximal end with sidewalls; 
         FIG. 6  shows a perspective view of an electrical terminal in accordance with an embodiment of the present invention having a proximal end with multiple layers of material; and 
         FIG. 7  shows a perspective view of an electrical terminal in accordance with another embodiment of the present invention having a locking contact portion. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
       FIG. 1  shows a perspective view of an electrical terminal  10  in accordance with an embodiment of the present invention. The terminal  10  includes a contact portion  12  having a contact portion base  13  and sides  14 ,  16 ,  18 ,  20  forming a generally rectangular structure. The contact portion  12  further includes four pairs of contact arms  22 ,  24 ,  26 ,  28 , each extending from a respective one of the sides  14 ,  16 ,  18 ,  20 . As described in more detail below, the contact arms  22 ,  24 ,  26 ,  28  are arranged to receive a mating electrical component, such as a round or square pin, such that each pair of contact arms  22 ,  24 ,  26 ,  28  contacts the mating electrical component. 
     The terminal  10  also includes a spring arrangement  30  that includes four spring arms  32 ,  34 ,  36 ,  38 . Each of the spring arms  32 ,  34 ,  36 ,  38  has a respective spring body  40 ,  42 ,  44 ,  46  disposed along a central portion of a respective pair of the contact arms  22 ,  24 ,  26 ,  28 . Each of the spring arms  32 ,  34 ,  36 ,  38  also includes a respective spring head  50 ,  52 ,  54 ,  56  in contact with a respective pair of the contact arms  22 ,  24 ,  26 ,  28  near a distal end  58  of the contact portion  12 . The spring heads  50 ,  52 ,  54 ,  56  apply a force to the respective pair of contact arms  22 ,  24 ,  26 ,  28  in a direction that is toward an opposite pair of the contact arms—e.g., the spring head  56  applies a force to the contact arms  28  in a direction toward the opposite pair of contact arms  24 ; similarly, the contact head  34  applies a force to the contact arms  24  in a direction toward the opposite pair of contact arms  28 . As explained in more detail below, the configuration of the spring arrangement, and in particular the contact of the spring heads to the respective pairs of contact arms, increases the normal force that will be applied to a mating electrical component, such as a pin. 
     Although the embodiment shown in  FIG. 1  is a four-sided generally rectangular structure, embodiments of the present invention may include less than or more than four sides to create a different type of generally polyhedron structure. For example, a three-sided structure may have a generally triangular cross section, and a five-sided structure may have a generally pentagonal cross section. In such a case, a spring would not apply a force to a set of contact arms in a direction toward an opposite pair of contact arms since the above examples have an odd number of sides. Rather, the springs in these embodiments will apply a force on the respective contact arms in a direction toward a central axis of the contact portion  12 , such as the axis  59  shown in  FIG. 1 . In addition to the embodiments described above, a contact portion, such as the contact portion  12 , may have an odd or even number of sides, but have contact arms extending out from only some of the sides. For example, the contact portion  12  could be configured as an octagonal structure, but have contact arms extending out from only four sides. 
     A terminal, such as the terminal  10  may be effective for use in high current applications, where a soft copper conductor may lose its ability to apply a normal force in the presence of the potentially high heat associated with some high current applications. To help avoid this problem, some prior art electrical terminals use a copper or other metal alloy that may have better high-temperature properties; however, this is often to the detriment of the conductivity which may be better with a more pure copper or with a softer copper or other metal alloy. In the electrical terminal shown in  FIG. 1 , the contact portion  12  can be made from a relatively soft copper material, such as C151, or other material having good conductivity such as an aluminum alloy, while the spring arrangement  30  can be made from a relatively stiff and strong material, such as 301 stainless steel. 
     Although the tension applied to the contact arms  22 ,  24 ,  26 ,  28  by the spring heads  50 ,  52 ,  54 ,  56  would usually be adequate to keep the components in their relative orientations, the embodiment shown in  FIG. 1  provides an additional feature to further ensure that the relative orientation is maintained. As shown in  FIG. 1 , each of the spring bodies  40 ,  42 ,  44 ,  46  has at least a portion disposed between a respective pair of the contact arms  22 ,  24 ,  26 ,  28 , which helps to ensure that the spring heads  50 ,  52 ,  54 ,  56  are in the proper position and apply the force generally equally between each of the respective contact arms in the pairs of contact arms  22 ,  24 ,  26 ,  28 . In particular, the arrangement of the contact arms  22 ,  24 ,  26 ,  28  and the associated spring bodies  40 ,  42 ,  44 ,  46  helps to ensure that relative lateral movement between them is prohibited, or at least inhibited or otherwise limited. Also shown in  FIG. 1 , the contact portion  12  includes a platform  60  configured to connect with a wire or other electrical component, for example, by sonic welding. The platform  60  extends from a proximal end  61  of the contact portion  12 . 
       FIG. 2  shows a fragmentary view of the electrical terminal  10  shown in  FIG. 1 . In addition to the spring arms  32 ,  34 ,  36  (not visible in  FIG. 2 ),  38 , and the respective spring bodies and spring heads (not labeled in  FIG. 2 ), the spring arrangement  30  includes a spring base  62 , from which each of the spring arms  32 ,  34 ,  36 ,  38  extends outwardly. The spring base  62  and the spring arms  32 ,  34 ,  36 ,  38  are, in this embodiment, made from a single piece of material. The spring base  62  includes a support structure, which in this embodiment includes an aperture  64  disposed therethrough for receiving a mating electrical component, such as the round pin  66 . The aperture  64  is sized to receive the pin  66  with a clearance fit, or even a slight interference fit. This configuration helps to support the pin  66  and allows the terminal  10  to mate with much longer pins than might otherwise be possible. That is, if the only contact between a long pin, such as the pin  66 , and the electrical terminal  10  was at the contact arms  22 ,  24 ,  26 ,  28  (see  FIG. 1 ), an undesirable amount of relative motion between the pin  66  and the terminal  10  could occur. Having a spring base  62  configured with the aperture  64  provides the additional support required to reduce this relative motion and thus allow the terminal  10  to interface with longer pins, such as the pin  66 . 
     In the embodiment shown in  FIG. 2 , the support structure further includes a neck  68  disposed around the aperture  64 , and it may be formed, for example, through a drawing process. It is understood that not all embodiments of the present invention may have this feature; however, this configuration has the advantages of providing additional support for the pin  66 , and may further strengthen the spring arrangement  30 . Although the aperture  64  is generally round, it may be other shapes, for example, square, which would accommodate a pin having a square cross section. As seen in  FIG. 2 , the spring base  62  is disposed within the contact portion  12 , and in particular, within the contact portion base  13 . Also shown in  FIG. 2  is that the spring arms  32 ,  34 ,  36 ,  38  extend through the contact portion  12  and along an outside of a respective pair of contact arms (see also  FIG. 1 ). 
     Although only one of the contact arms  28  is shown in  FIG. 2 , it is understood that the pin  66  will be in contact with all of the contact arms  22 ,  24 ,  26 ,  28 —see  FIG. 1 . In particular, the contact arms  22 ,  24 ,  26 ,  28  will be in contact with and provide support at a distal portion  70  of the pin  66 . In contrast, the spring base  62 , which includes the aperture  64  and neck  68 , provides support at a proximal portion  72  of the pin  66 . In general, the contact arms  22 ,  24 ,  26 ,  28  and the spring base  62  provide support at substantially opposite ends  70 ,  72  of the pin  66 , even if the support is provided at points located somewhat inwardly from the farthest ends of the pin  66 . As described above, the spring heads  50 ,  52 ,  54 ,  56  apply a force to and provide strength for the contact arms  22 ,  24 ,  26 ,  28 , and in this way, also help to support the pin  26  at the distal portion  70 . 
       FIG. 3  shows a perspective view of an electrical terminal  74  in accordance with another embodiment of the present invention. The terminal  74  includes a contact portion  76  having a contact portion base  78  and four sides  80 ,  82 ,  84 ,  86  forming a generally rectangular structure. The contact portion  78  further includes four contact arms  88 ,  90 ,  92 ,  94 . As described above with regard to the embodiment shown in  FIG. 1 , the terminal  74  shown in  FIG. 5  may also have fewer than or more than four sides, with at least some of them having at least one contact arm extending therefrom. The terminal  74  also includes a spring arrangement  96 , which has four spring arms  98 ,  100 ,  102 ,  104 . Each of the spring arms  98 ,  100 ,  102 ,  104  includes a pair of elongate members forming respective spring bodies  99 ,  101 ,  103 ,  105  which straddle a respective one of the contact arms  88 ,  90 ,  92 ,  94 , and which terminate in a spring head  106 ,  108 ,  110 ,  112 . 
     The spring heads  106 ,  108 ,  110 ,  112  each contact a respective one of the contact arms  88 ,  90 ,  92 ,  94  near a distal end  114  of the contact portion  76  and apply a force in a direction toward an opposite one of the contact arms  88 ,  90 ,  92 ,  94 . More generally, each of the spring heads  106 ,  108 ,  110 ,  112  applies a force to a respective one of the contact arms  88 ,  90 ,  92 ,  94  in a direction toward a central axis  115  of the contact portion  76 . Like the terminal  10  shown in  FIG. 1 , the terminal  74  includes a platform  116  configured to connect with a wire or other electrical component, for example, by sonic welding. 
       FIG. 4  shows a fragmentary view of the electrical terminal  74  shown in  FIG. 3 . In addition to the spring arms  98 ,  100 ,  102  (not visible in  FIG. 4 ),  104 , and respective spring heads (not labeled in  FIG. 4 ), the spring arrangement  96  includes a spring base  118 , from which each of the spring arms  98 ,  100 ,  102 ,  104  extends outwardly. The spring base  118  and the spring arms  98 ,  100 ,  102 ,  104  are, in this embodiment, made from a single piece of material. The spring base  118  includes a support structure, which in this embodiment includes an aperture  120  disposed therethrough for receiving a mating electrical component, such as a round pin  122 . The aperture  120  is sized to receive the pin  122  with a clearance fit, or even a slight interference fit. This configuration helps to support the pin  122  and allows the terminal  74  to mate with much longer pins than might otherwise be possible. Similar to the terminal  10  shown in  FIGS. 1 and 2 , the spring base  118  of the terminal  74  supports the pin  122  at a proximal portion  123  of the pin  122 , while the contact arms  88 ,  90 ,  92 ,  94 —see also FIG.  1 —support a distal portion  125  of the pin  122 . 
     As described above, an aperture, such as the aperture  120 , need not be round, but can be configured to accommodate mating electrical components of different cross-sectional shape, such as a square pin. Similar to the terminal  10  shown in  FIGS. 1 and 2 , the aperture  120  in the spring base  118  includes a neck  124 , which may be formed, for example, through a drawing process. As described above, not all embodiments of the present invention may have a neck, such as the neck  124  surrounding the aperture  120 ; however, this configuration has the advantages of providing additional support for the pin  122 , and may further strengthen the spring arrangement  96 . 
       FIG. 5  shows an electrical terminal  126  with a configuration similar to terminal  10  shown in  FIG. 1 . The terminal  126  includes a contact portion  128  and a spring arrangement  130 . A difference is seen, however, in a proximal end  132  of the terminal  126 , where a platform  134  is bounded by two sides  136 ,  138  oriented generally perpendicularly to the platform  134 . As shown in  FIG. 5 , the two sides  136 ,  138  at the proximal end  132  are extensions of two of the sides that define the contact portion  128 . Configuring the proximal end  132  of the terminal  126  with the vertical (as shown in  FIG. 5 ) sides  136 ,  138 , helps to strengthen the platform  134  and may provide additional resistance to bending. This may be particularly important in an application where the terminal  126  is of a very small size. 
     As described above, a terminal, such as the terminal  126 , may be particularly well-suited to high-current, high-temperature applications where the spring arrangement  130  is able to maintain its strength. In these types of applications, it is also desirable to have other portions of the terminal configured to better handle the high-current, high-temperature environment. As shown in  FIG. 5 , the platform  134  includes two layers of material  140 ,  142 . As described above in conjunction with  FIGS. 1 and 3 , a platform, such as the platform  134 , may provide a point of connection for an electrical component, such as a wire or other conductor. Providing multiple layers of material, such as the layers  140 ,  142 , helps to ensure that there is enough material to handle the high-current, high-temperature applications to which the terminal  126  may be subjected. This may be particularly important, since the platform  134  may be made from the same high conductivity material as the rest of the contact portion  128 , for example, a copper or aluminum alloy, and therefore, may be a relatively low strength material; hence, a single layer of this material may not provide the strength and durability desired for these applications. 
       FIG. 6  shows an electrical terminal  144 , which includes a contact portion  146  and a spring arrangement  148 . A proximal end  150  of the terminal  144  is configured with a platform  152  having four layers of material  154 ,  156 ,  158 ,  160 , which may provide even more current carrying capability than the two layer platform  134  shown in  FIG. 5 . These layers of material may be formed, for example, from the four sides  162 ,  164 ,  166 ,  168  of the contact portion  146 . Thus, in at least some embodiments, the contact portion  146  can be stamped from a single piece of conductive material, and then folded to define a generally rectangular polyhedron, and then further folded at a proximal end, such as the proximal end  150 , to create the layers of material  154 ,  156 ,  158 ,  160 . In this way, the layers of material  154 ,  156 ,  158 ,  160  comprise a portion of the four sides  162 ,  164 ,  166 ,  168 . Alternatively, a platform, such as the platform  152  can be built-up with additional layers of material as required for a particular application. In this way, at least some embodiments of the present invention can be specifically tuned for particular applications which may have different current carrying requirements and temperature requirements. 
       FIG. 7  shows an electrical terminal  170 , which includes a contact portion  172  and a spring arrangement  174 . A proximal end  176  of the terminal  170  includes a platform  178  having two sidewalls  180 ,  182 . The contact portion  172  includes a locking feature  184  that allows the contact portion to lock onto itself. Although the contact portion  172  is octagonal, and thus has eight sides  186 ,  188 ,  190 ,  192 ,  194 ,  196 ,  198 ,  200 , only four of the sides  186 ,  188 ,  190 ,  192  have contact arms  202 ,  204 ,  206 ,  208  extending therefrom, illustrating that in at least some embodiments, not every side of a contact portion need have a contact arm or arms extending from it. 
     Having a contact portion with a locking feature, such as the contact portion  172  having the locking feature  184 , helps to increase the strength of the terminal  170  by eliminating any open channels running a full length of the sides  186 ,  188 ,  190 ,  192 ,  194 ,  196 ,  198 ,  200  formed when the contact portion is folded into a rectangular or other polyhedron shape, such as the octagonal shape shown in  FIG. 7 . It also may increase the electrical performance of the terminal  170 , by connecting all of sides of the contact portion  172  electrically. Although the locking feature  184  includes a male tab and a mating slot, both generally configured as a trapezoid, locking features in accordance with embodiments of the invention may have other geometric configurations. 
     Alternatively, electrical terminals in accordance with embodiments of the present invention may have a locking feature that does not include interconnecting geometric shapes. For example, a locking feature may be defined by the addition of a material or by a process for connecting the sides together. For example, the side  162  of the contact portion  146  shown in  FIG. 6  includes an open channel  210 , which could be laser welded along its length to create a locking feature. Other methods and/or materials for closing the channel  210  to create a locking feature could include, for example, sonic welding, solder, or a conductive adhesive. Locking features of this type may also add strength and improve electrical performance of the terminal. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.