Abstract:
An elongated terminal strip has a series of terminals, each having a compliant portion engaged laterally between a first and second portion which electrically engage to respective electrical components having a tendency to vibrate. Each compliant portion extends longitudinally with respect to the terminal strip between two adjacent cut lines. A plurality of leading and trailing slots extend longitudinally within the compliant portions and are disposed alternately through one then the other adjacent cut lines. The step of dispensing or cutting the terminal away from the terminal strip exposes the slots along the cut edge enabling the flexing capability of the compliant portion.

Description:
TECHNICAL FIELD OF THE INVENTION 
     This invention relates to a terminal strip for making terminals and more particularly to terminals having a compliant portion and to a method for making such. 
     BACKGROUND OF THE INVENTION 
     A terminal is known to electrically interconnect one electrical component to another through a pressure fitted electrical connection at either or both ends. The terminal is typically made of a cost effective tin plated copper alloy providing a reliable electrical connection. When making or breaking the electrical connection, the tin oxide layer of the terminal essentially cracks permitting clean tin to ooze out through the crack. The clean tin bonds to the connector of the electrical component providing a very stable electrical connection 
     Fretting corrosion is a known phenomenon which can cause otherwise stable tin plated copper alloy electrical connections to fail. For fretting corrosion to occur, there must be a small degree of movement or rubbing between the pressure fitted tin plated terminal interface. Such movement is usually the result of vibration from one or both of the electrical components. Fretting or the rubbing of the terminal interface together typically occurs only when the vibration or displacement between components is of a small magnitude measured in microns (i.e. 10-100 microns) and the pressure between the interface is low. Fretting corrosion occurs when the once clean tin is exposed to the air as a result of movement, wherein the tin quickly forms into an electrically insulating tin oxide film. With repeated motions, the debris of tin oxide builds up until the electrical connection fails. 
     Fretting corrosion can be eliminated by preventing the electrical components from vibrating, or utilizing gold or silver based terminal contact coatings which resist fretting corrosion. Unfortunately, either means may not be practical or may be cost prohibited depending upon the application. 
     SUMMARY OF THE INVENTION 
     The present invention provides an elongated terminal strip having a series of terminals and Cut lines disposed therebetween. Each terminal has a compliant portion extending longitudinally with respect to the elongated terminal strip from one laterally extended cut line to the next succeeding cut line. An electrical contact first portion extends laterally outward from the compliant portion between the two adjacent cut lines. An opposing second portion, extends laterally outward from the opposite side of the compliant portion. The first and second portions electrically engage respective electrical components. If either electrical component should vibrate, the compliant portion of the terminal will extend, retract or twist, in other words, will move within a three dimensional array, thereby enabling either the first or second portions of the terminal to move relative to the respective vibrating electrical component preventing any relative movement at the electrical contact points and eliminating fretting concerns. 
     The compliant portion has at least one slot which extends longitudinally with respect to the elongated terminal strip from either one of the adjacent cut lines to an end of the slot disposed within the compliant portion of the terminal. Preferably, the compliant portions have a plurality of slots which extend from both of the adjacent cut lines. For instance, preferably the compliant portion has a leading slot extended rearward within the compliant portion. The leading slot is disposed between two trailing slot which extend forward within the compliant portion from a succeeding cut line to the cut line communicating with the leading slot. The trailing slots have ends disposed within the compliant portion lying slightly rearward of the cut line communicating with the leading slot. The ends of the trailing slots are disposed laterally outward with respect to the leading slot. 
     A feature of the present invention is the reduction of fretting corrosion caused by vibrating electrical components. 
     Another feature of the invention is the production of a cost effective and robust compliant portion of the terminal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The presently preferred embodiments of the invention are disclosed in the following description and accompanying drawings wherein: 
     FIG. 1 is a partially exploded perspective view of a terminal strip of the present invention, 
     FIG. 2 is a partially exploded perspective view of a second embodiment of a terminal strip of the present invention; and 
     FIG. 3 is partially exploded perspective view of a third embodiment of a terminal strip of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a terminal strip  10  of the present invention has a series of terminals  12  generally aligned laterally across the longitude of the terminal strip  10 . A substantially planar compliant portion  14  is engaged between an electrical contact first portion  16  and an electrical contact second portion  18 . The compliant portion  14  extends longitudinally with respect to the elongated terminal strip  10  in a forward direction from a trailing cut line  20  to a leading cut line  22 . The compliant portion  14  of the terminal  12  is substantially identical to the next succeeding compliant portion  14  of the next terminal  12  along the terminal strip  10 . Interconnecting each terminal  12  along the terminal strip  10  are a series of connecting portions  24 . Each connecting portion  24  extends rearward from the trailing cut line  20  of one terminal  12  to the leading cut line  22  of the next succeeding terminal  12 . The connecting portion  24  has an indexing hole  26  which receives a protrusion from a manufacturing cutting machine (not shown) to align the terminal strip  10  prior to cutting the terminal  12  off from the terminal strip  10  along the trailing and leading cut lines  20 ,  22 . After the terminals  12  are formed and cut, the cut connecting portion  24  becomes scrap material. 
     Providing the flexibility within the compliant portion  14  of the terminal  12  is a leading slot  28 . Leading slot  28  extends rearward from the leading cut line  22  and longitudinally with respect to the terminal strip  10 . The leading slot  28  has an end  30  disposed within the compliant portion  14  slightly forward of the trailing cut line  20  and an opposite end  32  disposed either on the leading cut line  22  or slightly within the connecting portion  24  disposed adjacent to and forward of the compliant portion  14 . Providing additional flexibility of the compliant portion  14  are preferably two longitudinally extended tailing slots  34 . The trailing slots  34  extend forward from the trailing cut line  20  and longitudinally with respect to the terminal strip  10 . Each trailing slot  34  has an end  36  disposed within the compliant portion  14  slightly rearward of the leading cut line  22  and an opposite end  38  disposed either on the trailing cut line  20  or slightly within the connecting portion  24  disposed adjacent and rearward of the compliant portion  14 . 
     A major portion of the leading slot  28  contained within the compliant portion  14  is disposed substantially between the two trailing slots  34 . The two ends  36  of the trailing slots  34  are disposed laterally outward from and on either side of the leading slot  28 . The leading slot  28  and the trailing slots  34  are substantially parallel to one another. The configuration of the leading and trailing slots  28 ,  34  provide a three dimensional flexing capability of the compliant portion  14 . In other words, the electrical contact first portion  16  may move toward or away from the contact second portion  18  of the terminal  12  as a result of electrical component vibrations. Similarly, the first and second portions  16 ,  18  may twist, move side to side, or move up and down with respect to one another. This flexibility of the compliant portion  14  ensures that the electrical contact points of the first or second portions  16 ,  18  and the respective electrical components do not rub as a result of component vibration. In this way, fretting, corrosion is avoided or at least reduced. Increasing the number of alternating trailing and leading slots  34 ,  28 , or increasing the lengths of the slots within the compliant portion  14  can further enhance the flexing capability of the terminal  12  if the need is required. 
     During the manufacturing process, the terminal strip  10  is pre-stamped, containing all of the leading and trailing slots  28 ,  34  and indexing holes  26  previously described. The step of cutting the connecting portion  24  away from the leading end of the terminal strip  10 , along the leading cut line  22 , cuts off the opposite end  32  of the leading slot  28  exposing the leading slot  28  along the cut edge of the compliant portion  14 , as shown in FIG.  1 . Likewise, the step of cutting the terminal  12  away from the subsequent leading end of the terminal strip  10 , along the trailing cut line  20  leaves the opposite ends  38  of the trailing slots  34  behind within the next succeeding connecting portion  24  of the terminal strip  10 . The trailing slots  34  of the separated terminal  12  are now exposed through the opposite cut edge of the compliant portion  14 . In essence, the act of cutting or dispensing the terminals  12  from the terminal strip  10  creates or enables the flexibility of the compliant portion  14 . 
     Referring, to FIG. 2, a second embodiment of the present invention is illustrated wherein the connecting portions  24  of the first embodiment are eliminated so that the compliant portions  14 ′ of the terminals  12 ′ are end to end or juxtaposed. The terminal strip  10 ′ of the second embodiment is indexed within the manufacturing cutting machine utilizing any one of the trailing or leading slots  34 ′,  28 ′ as the indexing hole  26  of the first embodiment. The trailing cut line  20  and the next succeeding or trailing, cut line  22  of the first embodiment coincide in the terminal strip  10 ′ of the second embodiment, forming a singular common cut line  40 . The terminal  12 ′ extends from cut line  40  to the next succeeding common cut line  40 . The leading slot  28 ′ extends rearward from the cut line  40  into the compliant portion  14 ′. The trailing slots  34 ′ extend forward from the next succeeding common cut line  40 . The leading and trailing slots  28 ′,  34 ′ have the same configuration within the compliant portion  14 ′ as previously described for the terminal strip  10  of the first embodiment. 
     Referring to FIG. 3, a third embodiment of the present invention is shown. Unlike the first and second embodiments where the terminals  12  or  12 ′ are identical, the series of terminals  12 ″ of the terminal strip  10 ″ comprise alternating leading and trailing terminals  42 ,  44 . Although not identical to one another as are the terminals  12 ′ of the second embodiment, the leading terminal  42  of the third embodiment is substantially a mirror image of the trailing terminal  44 . The leading terminal  42  extends rearward along the terminal strip  10 ″ from a second cut line  48  to a first cut line  46 . The trailing terminal  44  is disposed adjacent to the leading terminal  42  and extends rearward from the first cut lie  46  to the next succeeding second cut line  48 . 
     The leading terminal  42  has a trailing slot  50  which extends forward from the first cut line  46  to an end  52 . The end  52  of the trailing slot  50  is disposed within the compliant portion  54  slightly rearward of the respective second cut line  48 . The leading terminal  42  preferably has two leading slots  56  disposed on either side of the trailing slot  50 . The leading slots  56  extend rearward from the second cut line  48  to respective ends  58 . The end  58  is disposed within the compliant portion  54  slightly forward of the first cut line  46  and laterally outward with respect to the trailing slot  50 . 
     The trailing terminal  44  has the leading slot  28 ″ extending rearward within the compliant portion  14 ″ from the first cut line  46  to the end  30 ″. The end  30 ″ is disposed within the compliant portion  14 ″ slightly forward of the second cut line  48 . Furthermore the leading slot  28 ″ of the trailing terminal  44  is collinear to the trailing slot  50  of the leading terminal  42  and communicates with the trailing slot  50  through the first cut line  46 . The trailing terminal  44  also has preferably two trailing slots  34 ″ which extend forward from the second cut line  48  within the compliant portion  14 ″ to the end  36 ″ which is disposed slightly rearward from the first cut line  46 . Like the first and second embodiments, the leading slot  28 ″ is disposed substantially between the two trailing slots  34 ″. The ends  36 ″ of the trailing slots  34 ″ are disposed laterally outward with respect to the leading slot  28 ″. Each respective trailing slots  34 ″ of the trailing terminal  34  are collinear with the respective leading slots  56  of the leading terminal  42  and thereby communicate through the second cut line  48 . 
     Although the preferred embodiment of the present invention have been disclosed, various changes and modification may be made thereto by one skilled in the art without departing from the scope and spirit of the invention as set forth in the appended claims. Furthermore, it is understood that the terms used herein are merely descriptive, rather than limiting and various changes may be made without departing from the scope and spirit of the invention.