Abstract:
A contact arrangement ( 10 ) comprising fork-shaped contacts ( 15 ) that engage opposite faces of a blade contact ( 18 ). For good heat dissipation together with low transition resistance, the contact arrangement is made up of multiple planar, i.e., plate-shaped, fork contacts ( 15 ), which are supported and connected to each other on a shaft-like carrier ( 16 ) that is joined to a perpendicular connecting unit ( 14 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Applicant claims priority from German patent application no. 10 2010 044 612.2 filed Sep. 1, 2010. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to an electrically conductive contact arrangement. 
     In electrically conductive contact arrangements in systems of high specific power density, it is essential, on the one hand, to keep the Joule heating small through having minimal thermal resistances of the contact units that are to be, or have been, connected to each other, and, on the other hand, to remove the residual heat through good heat dissipation into other current-carrying components. In this context, the decisive parameters are selecting materials for the contact units along with their coatings, having the greatest possible number of contact points, determining the magnitude of the contact forces compatible with reasonable ease of operation, and ensuring the largest possible masses and cross-sections in the contact arrangement. 
     According to the prior art, in electrically conductive contact arrangements for high-performance applications, either contact units have been known that are manufactured with great geometric precision and are therefore expensive, or the contact arrangements have been provided with expensive, delicate spring contacts as supplemental parts. 
     From DE 10 2008 031 571 A1, an electrically conductive contact arrangement is known for high-performance current transmission, in which one pole is formed by multiple spring contacts, which together constitute a plug-in aperture and which are supported, each with spacing from the others, within attachment openings of a contact support that is made of insulating material, said electrically conductive contact arrangement therefore offering neither optimal electrical contacting nor optimal heat dissipation. 
     It is the objective of the present invention to create an electrically conductive contact arrangement of the aforementioned type, which is less expensive and can be manufactured cost-effectively in large quantities and which in addition to low transition resistances offers excellent heat dissipation. 
     SUMMARY OF THE INVENTION 
     As a result of the measures according to the present invention, an electrically conductive contact arrangement is created, which can be manufactured in a simple manner by placing spring fork contacts in a row and which can be adjusted to the relevant, or calculated, maximum current transmission power. Thus planar spring fork contacts may be manufactured cost-effectively, for example, as a simple stamping part and in large quantities. The same applies to assembling and holding together this multiplicity of planar spring fork contacts on one carrier and connecting it to a connecting unit. As a result of this way of assembling planar. i.e., plate-shaped, spring fork contacts, the geometry of these contacts may be easily adjusted to the requirements of specific applications, and also with respect to the mating contact. The characteristics of the spring fork contacts are relatively easy to model in one plane due to the planar quality of the component. 
     The individual spring fork contacts may be strung, for example, onto a tubular carrier in a simple manner in any quantity, and then they may be fixed, or joined, to form a massive composite. A carrier of this type provides a multiplicity of contact points and at the same time a large mass for heat transport, while maintaining a high packing density. 
     Manufacturing methods using roller burnishing yield the massive composite, whereby the connecting points may be gas-tight and cold-welded so that the lowest transition resistances may be achieved. 
     The individual spring fork contacts may be held on the carrier in such a way that they are arranged either all in one packet, directly contacting each other, or in multiple adjoining packets. 
     Even the stringing of the spring fork contacts onto the carrier is accomplished in a rotationally fixed arrangement. 
     A reduction in the plug-in forces is possible because, due to the assembly of spring fork contacts having springs of alternating orientations on the carrier, the blade may be inserted into the spring fork contact unit in a substantially gentler manner due to the serial contacting. It is preferred that the two spring legs of a spring fork contact be of varying lengths and that adjoining spring fork contacts be rotated 180° about their central axis. 
     By stringing the individual spring fork contacts, which are configured, for example, as sheet metal or as stamped metal, onto the carrier, further arrangements of function elements are optionally possible. Thus, for example, one or more connecting units as well as elements to ensure a latching support of the spring fork unit within a housing may be optionally strung as intermediate- and/or end elements. 
     One or more connecting units may be arranged on corresponding areas on the end side of, or between spring fork contacts. In the case of the axial orientation, the connecting unit is integrated with the carrier in a way that is technically simple in production terms, thus yielding a very compact design, and in the case of the right-angle orientation, various optional angular positions are possible between the axis of the connecting unit and the axis of the carrier. 
     The connecting unit may be provided as a crimped element or as a screw element for the relevant conductor or conductors. In addition, by providing two or more connecting elements, division into two or more terminals is advantageously possible at high current levels. 
     A selectable arrangement of the housing latching elements is also achieved with the stringing of the spring fork contacts. 
     A blade contact unit that fits with the fork-shaped spring contact unit is also advantageously configured so as to be planar and plate-shaped, whereby depending on the installation space, the connecting unit may be arranged so as to be perpendicular or transverse with respect to the insertion direction of the blade contact. This planar, plate-shaped configuration provides the option of inserting the blade contact into the female contact device both from the end face as well as longitudinally. This is advantageous for use in the most varied kinds of configurations of plug-in connectors. The design as a right-angled contact is advantageous in applications in which the users during operation must be protected with shock hazard protection and/or figure protection; the relevant grip opening is never much larger than the material thickness of the blade contact. 
     As a flat component, the blade contact is easy to modify. Various cutouts in the contact area are possible, on the basis of which the plug-in process may be further optimized by sliding the spring forks serially. This provides for a further reduction in the plug-in forces and support for a gentle insertion of the blade contact into the spring fork contacts. 
     The blade contact unit is provided with a housing locking element, in the area of the connecting unit, for example. 
     The blade contact unit may be manufactured in a simple manner. 
     Further details of the invention may be derived from the following description, in which the invention is described and explained in greater detail on the basis of the exemplary embodiments that are depicted in the drawing. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of an electrically, conductive contact arrangement made of a fork-shaped spring contact unit and a blade contact unit in the electrically connected, i.e., plugged-together, state in accordance with a first exemplary embodiment of the present invention. 
         FIG. 2  is an exploded isometric view of the contact arrangement of  FIG. 1 , but in accordance with a variant. 
         FIG. 3  is an isometric view of a spring fork contact of the contact arrangement of  FIG. 1 . 
         FIG. 3A  is a partial sectional view of the contact arrangement of  FIG. 1 . 
         FIG. 4  is an isometric view of a spring contact arrangement of a second embodiment of the invention and in a state in a one assembly step. 
         FIG. 5  is an isometric view of a spring contact unit in accordance with a third embodiment of the present invention in the assembled state. 
         FIG. 6  is an enlarged isometric view of the free front, or top, area of the spring contact unit of  FIG. 1 , but in accordance with a fourth exemplary embodiment of the present invention. 
         FIG. 6A  is a partial elevation view of a fork contact of the unit of  FIG. 6 . 
         FIG. 7  is an exploded isometric view of a contact arrangement having a spring contact unit in accordance with  FIG. 1  and a blade contact unit according to another embodiment of the invention. 
         FIG. 8  is an elevation view of a contact arrangement similar to  FIG. 7 , but with a blade contact unit in accordance with another embodiment of the present invention and in the plugged-together, i.e., electrically contacting state. 
         FIG. 9A  and  FIG. 9B  are isometric views showing blade contacts of blade contact units in accordance with variants of the invention. 
         FIG. 10  is an isometric view of a spring contact unit in accordance with another embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an electrically conductive contact arrangement  10  for plug-in connections handling high transmission power, as is the case with electrically operated motor vehicles, for example. The contact arrangement includes a fork-shaped spring contact unit  11  and a blade contact unit  12  that are connected together. Spring contact unit  11  has a multiplicity of planar, plate-shaped spring fork contacts  15 , or fork contacts, which are strung on a shaft  16  in the form of a tubular carrier  16 , and has a connecting unit  14  that is also connected to the carrier. The fork contacts extend along a stack axis  52 . 
     Blade contact unit  12  has a planar, plate-shaped blade contact  18  which has electrically conductive opposite faces  18 A,  18 B ( FIG. 6A ). Each fork contact forms a slot  17  ( FIG. 3 ) and each fork contact  15  resiliently engages the blade contact opposite faces. A connecting unit  19  ( FIG. 1 ), is electrically connected to blade contact  18 . Connecting unit  14  is provided with fork contacts  15  in axial alignment, and connecting unit  19  is provided with blade contact  18  in axial alignment with the slots in the fork contacts. Connecting unit  14  has a threaded pin  21  extending perpendicular to axis  52 , for the screw attachment of an electrical conductor. Connecting unit  19  on blade unit  12  is configured as a crimped sleeve  22 , by means of which the relevant electrical conductor may be connected to blade contact unit  12  in crimped fashion. 
       FIG. 1  shows that the blade contact  18 , shown here as rectangular, is inserted into slots  17  of spring fork contacts  15  with a narrow side  38  of the blade contact at its top. However, it is also possible to insert identical blade contact unit  12  into slot  17  of spring fork contact  15  with one of its two longitudinal sides  39 ,  39 ′ in front (at the top). 
       FIG. 2  shows the assembly of spring contact unit  11 , which is made up of multiple spring fork contacts  15 , one of which is depicted in  FIG. 3  in an enlarged view. Each spring fork contact  15  has a rearward R base area  25 , which is provided with a cutout in the form of a borehole  26 . The hole  26  is preferably circular to allow the fork contact to pivot. The base area  25  of the contact preferably leaves a width W of material between the hole  26  and the slot  17 . Each fork contact has two spring legs  27 ,  28  that protrude forwardly (F) in  FIG. 1 . The legs of each fork contact have upper, or forward free ends  27   e ,  28   e  that form contact points or surfaces  29 ,  30  which point generally towards each other, and that protrude into slot  17 . The contact points  29 ,  30  contact the double-sided external surfaces of blade contact  18 . In one area adjoining the base of slot  17 , the external edges of spring legs  27 ,  28  are each provided with a notch  31 ,  32  which facilitate latching retention in an undepicted plug-in connector housing. 
     Spring fork contact  15  is manufactured from a planar, relatively thin metal plate, preferably as a single-piece stamped part. However, other, familiar, cutting methods are also suitable, e.g., laser cutting or water jet cutting. 
     In order to manufacture spring contact unit  11 , a multiplicity of spring fork contacts  15  ( FIG. 2 ), which in this exemplary embodiment are identical, stamped parts, are strung onto carrier  16 , which is a shaft in the form of a tubular sleeve. Connecting unit  14 , which is also provided with a borehole  24  ( FIG. 2 ), is strung onto carrier  16 , and then a number of fork contacts  15  are strung on both sides of this connecting unit  14 . According to one variant shown in  FIG. 2 , a locking element  33 ,  34 , whose slotted free ends are bent so that they point towards each other and are therefore shorter in the longitudinal extension, is placed on both sides of connecting unit  14 , in contrast to the completely assembled spring contact unit  11  of  FIG. 1 . Locking elements  33 ,  34 , for example, facilitate the latching retention of spring contact  11  in an undepicted plug-in connector insulating housing. 
     As can be seen in  FIGS. 1 and 2 , two packets  36 ,  37  of fork contacts  15  are provided in contact unit  11 .  FIG. 1  shows two stacks of fork contacts on opposite sides of the connecting unit, with each stack, or packet, having seven fork contacts. Fork contacts  15  of both packets  36 ,  37  are fixed to carrier  16  by an interior burnishing process. All fork contacts  15  and both packets  36 ,  37  are in alignment. As shown in  FIG. 3A , the fork contacts lie in a stack and the fork contacts lie facewise adjacent and preferably in direct contact with adjacent fork contacts in the stack. 
       FIG. 4  shows a contact arrangement  110  of another embodiment of the invention, in which carrier  116  is an integral part of connecting unit  114 . Tubular carrier  116  merges axially into a larger-diameter crimped sleeve  122  of connecting unit  114 , so that connecting unit  114  is positioned perpendicular to the orientation of the spring fork contacts  15 .  FIG. 4  shows fifteen identical spring fork contacts  15  strung onto carrier  116  and fixedly connected to each other as one single packet and to carrier  116 , for example, through an interior burnishing, so as to create spring contact unit  111 . 
     In the embodiment of contact arrangement  210  of  FIG. 5 , a multiplicity of fork contacts  15  are strung on a tubular carrier  216  to form one single packet (as in  FIG. 4 ), creating spring contact unit  211 . An eye  241  of a connecting unit  214  is attached on one end of carrier  216 . On a peripheral area of eye  241 , connecting unit  214  has a crimped sleeve  222 , whose axis is preferably perpendicular to the longitudinal axis of carrier  216 . Crimped sleeve  222  extends beyond a partial area of carrier  216  and therefore of base area  25  ( FIG. 3 ) of fork contacts  15 . Before connecting unit  214  is fixed on carrier  216 , the longitudinal axis of crimped sleeve  222  may be adjusted so that it lies at an angle with respect to the axis of carrier  216 . 
       FIG. 6  shows an embodiment of spring contact unit  311  in the form of individually adjoining spring fork contacts  315 , whose spring legs  327 ,  328  are of varying lengths. In this embodiment, adjoining spring fork contacts  315  are identical, but these spring fork contacts  315  are arranged so as to be alternately rotated 180° about their longitudinal central axis. This means that contact points  329 ,  330  lie at different heights.  FIG. 6A  shows the contact points  329 ,  300  being vertically spaced by distance C along the blade  18 . 
     In  FIG. 6  contact points  329 ,  330  are deflected one after the other in response to the insertion of a blade  18  of blade contact unit  12  in the insertion direction. As a result, the insertion, or plug-in force is reduced, and the blade contact  18  is inserted more gently into the packet, or adjoining packets, of spring fork contacts  15 ,  315 . Of course, adjoining spring fork contacts  15 ,  315  may also be arranged on the basis of more than two contact points  329 ,  330 , which are offset in the insertion, or plug-in, direction. 
     In the embodiment of contact arrangement  310  in  FIG. 7 , a spring contact unit  11  of the construction of  FIG. 1  is combined with a blade. Blade unit  312  has a crimped sleeve  322 , which is in axial alignment with blade contact  318 . In this blade contact unit  312 , contrary to what is depicted in  FIG. 1 , the contact plug-in direction is selected so as not to be along the longitudinal axis of blade contact unit  312  but rather in a direction that is transverse to the longitudinal extension of blade contact unit  312 . 
     A further difference between blade contact unit  312  and blade contact unit  12  in  FIG. 1  lies in the configuration of blade contact  318 . Blade contact  318  has a recess  343  on one of its ends facing away from crimped sleeve  322 . The recess extends from longitudinal edge  339  of blade contact  318  and in the insertion direction, and therefore creates a returning edge  345  from longitudinal edge  339  in the direction of narrow edge  338 . This means that during the insertion, the leading part of longitudinal edge  339  first achieves a contact connection with packet  37  of spring fork contacts  15 , situated opposite, whereas the trailing, returning part of longitudinal edge  339  achieves an electrical contact connection with the other, adjoining packet,  36  of spring fork contacts  15 . This signifies a reduction in the insertion, i.e. plug-in, forces that are occurring at this point in time between both units  11 ,  312 . It is also possible to configure the edge areas and their rounded connection in step-wise fashion in the direction of their thickness. 
     In the design of  FIG. 7 , crimped sleeve  322  has locking elements  346  on both sides of blade contact  318 . The locking elements facilitate latching retention and are an integral part of crimped sleeve  322 . 
     In  FIG. 8 , a contact arrangement  410  is depicted, whose spring contact unit  11  is identical to spring contact unit  11  in  FIG. 7  and  FIG. 1  and blade contact unit  412  is similar to blade contact unit  312  in  FIG. 7 . However, in  FIG. 8  the blade contact unit  412  is connected in plug-in fashion to blade contact unit  11  in its longitudinal extension. Connecting unit  412  is similar to connecting unit  312  in  FIG. 7 . Blade contact  418  corresponds to the shape of blade contact  318  in  FIG. 7 , except that here the leading edge is formed by a part of narrow edge  438  and, due to recess  443 , the trailing edge is formed by the returning part of narrow edge  438 . This means that the one longer area of blade contact  418  achieves a contacting connection with one packet  36  (or 37 in a 180° rotation of blade contact unit  412  about its longitudinal axis) from spring fork contacts  15  of spring contact unit  11 . Also, the other, shorter, i.e. returning, longitudinal area of blade contact  418  achieves a contacting connection with other packet  37  (or 36 in a 180′ rotation of blade contact unit  412  about its longitudinal axis). Here as well, connecting unit  419  has locking elements  446 . 
       FIGS. 9A and 9B  depict variants  318 ′,  418 ′ of configurations of blade contact  318 ,  418  in  FIGS. 7 and 8 , whereby in accordance with  FIG. 9A  the leading narrow or longitudinal edge, which is free in the insertion direction, is formed by an edge  348 ′ that is linear, has a stepped thickness, and is otherwise beveled, whereas in the variant according to  FIG. 9B , beveled edge  349 ′ is linear in the center with respect to its thickness and is stepped in both other thickness areas. 
       FIG. 10  shows a contact arrangement  510  in which only one fork contact  511  is shown, into which a blade contact unit ( 18  of  FIG. 6A ) may be inserted to create a connection. Fork contact unit  511  differs from unit  11  of  FIG. 1  in that carrier  516 , which here receives spring fork contacts  515  as one or more packets, is fixed to a circuit board  550  by a connecting unit  514 . For this purpose, the two ends of carrier  516 , which is here also tubular, are fixedly joined to a right-angled attachment bracket  521 ,  521 ′ of connecting unit  514 . Carrier  516  is fixed to short leg  551  of attachment bracket  521 ,  521 ′. Long leg  552  of attachment bracket  521 ,  521 ′ is attached to circuit board  550  at the appropriate location in an electrically conductive manner. 
     In the embodiment depicted in  FIG. 10 , spring fork contacts  515  of spring contact unit  511 , are provided with a short spring leg  527  and a long spring leg  528 , so that here as well contact points  529 ,  530  are situated in planes so they engage the faces of a blade contact sequentially in the plug-in direction. It is obvious that this spring contact unit may instead be furnished with spring fork contacts  15  in one or two packets. 
     In this way, contact points  529 ,  530  of varying-length spring legs  529 ,  528  are situated on different planes, because adjoining spring fork contacts  515  are arranged so as to be rotated 180° about their central longitudinal axis in alternating fashion. In other words, short and long spring legs  527 ,  528  are arranged so as to adjoin each other. 
     In accordance with undepicted exemplary embodiments, the modification of the plug-in forces is determined both on spring contact unit  11 ,  11 ′ as well as on blade contact unit  12 ,  112 ,  212 ,  312 ,  412 . Furthermore, instead of double packets of spring fork contacts  15 ,  15 ′, it is also possible to arrange more than two packets  36 ,  37  on one carrier. In addition, it is possible to provide two or more connecting units  14 ,  114 , both on spring contact units  11  as well as on blade contact units  12 ,  112 ,  212 ,  312 ,  412 , so that the current being supplied in both directions may be divided among multiple conductors to a specific unit  11 ,  12 . 
     The integral design of connecting unit  19 ,  119 , etc., with blade contact unit  12 ,  112 , etc., may be achieved using the so-called MIM (metal injection molding) process. 
     Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.