Abstract:
A tab terminal for quick-disconnect type connections is formed by bending a single strip of metal back upon itself. The strip includes inward embossments allowing the desired tab thickness to be obtained with less material while using material suitable for spring contacts or internal device conductors.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This Non-Provisional Application is national phase of International Application Number PCT/US2009/050616 filed Jul. 15, 2009, and claims benefits to U.S. Provisional Application Ser. No. 61/083,996 filed Jul. 28, 2008 and hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to tab-form electrical terminals for use with quick-connect type connectors and the like. 
     BACKGROUND OF THE INVENTION 
     Tab-form terminals provide a generally rectangular planar blade that may be received by a variety of different receptacles (connectors) including quick-connect receptacles. The latter quick-connect receptacles provide a channel, for example, with rolled edges capturing the blade between a channel base and the edges. Tab-form terminals may also be used with other receptacle types including “low insertion force” receptacles and connector blocks such as Insulation Displacement Contact Rast-5 connectors having different designs. Such tab-form terminals in the United States normally conform to the requirements of Underwriters Laboratories Inc. (UL) described in Standard for Safety for Electrical Quick-Connect Terminals, UL 310 Seventh Edition, Dated May 27, 2003 adopted as American National Standard (ANSI) ANSI/UL 310 hereby incorporated by reference. 
     Common receptacles for tab-form terminals compress the blade of the tab-form terminal between resilient elements to provide a contact pressure necessary to reduce the electrical resistance between the receptacle and the blade to prevent overheating of the connection caused by high resistance and to prevent accidental disconnection. These receptacles normally require that the blade of the tab-form terminal have a well-defined thickness (often approximately 0.032 inches) in order to ensure sufficient compressive force between the resilient surfaces while avoiding excess friction. 
     Different receptacles may contact different portions of a blade of the tab-form terminal with an expectation that the blade will be substantially planar. 
     SUMMARY OF THE INVENTION 
     The present invention provides a tab-form terminal using substantially less material than a standard tab-form terminal while working with a variety of different receptacles types. In one embodiment, the tab-form terminal of the present invention eliminates a separate manufacturing step needed to attach the tab-form terminal to a conductor by allowing the reduced thickness material of the tab-form terminal itself to continue as a conductor. Further, this material which may be a spring material (e.g. phosphor bronze) which flexibly supports switch contacts without the need to attach a separate material to the tab-form terminal. 
     Generally, the tab-form terminal of the present invention employs a single thin strip of metal having a thickness less than half the thickness of the desired terminal blade. The strip is folded lengthwise into two portions forming opposite faces of the terminal blade. The portions are separated by inwardly extending embossments to provide a blade having the desired overall thickness with substantially less material. 
     Specifically, the present invention provides a tab-form terminal presenting a generally planar blade for receiving along its length a quick-disconnect receptacle of the type comprising generally having opposed surfaces receiving and inwardly compressing outwardly opposed broad faces of the planar blade when received within the channel to provide an electrical connection thereto. The tab-form terminal is constructed of a single strip of metal having a width adapted to be received within a channel section of the receptacle and having an unfolded length longer than the blade and a thickness less than half a thickness of the blade. The length of the strip is divided by a bend extending across the width to fold the single strip of metal back over itself to form the outwardly opposite first and second broad faces of the blade, the strip of metal including inwardly extending spacing elements separating the broad faces by a separation distance greater than twice the thickness of the strip of metal. 
     It is therefore a feature of a least one embodiment of the invention to decrease the amount of material required to produce a tab-form terminal compatible with standard connectors. It is another feature of at least one embodiment of the invention to permit the fabrication of the tab-form terminal from standard strip stock without the need for wasteful or costly sheet cutting operations. 
     The bend may divide the single strip into unequal portions so that one opposed side extends beyond the blade as a conductor. 
     It is therefore a feature of a least one embodiment of the invention to permit a tab-form connector to be formed out of the same material used to provide an attaching electrical conductor without the need for the electrical conductor to be as thick as a standard tab-form terminal. 
     One opposed side may be attached to an electrical contact and the opposed side may be adapted to flex to make and break an electrical circuit. 
     It is therefore a feature of a least one embodiment of the invention to permit electrical switch elements to be terminated by tab-form terminals without the need to attach separate terminal materials to the switch components. 
     The spacing elements may be embossments extending along the width of the single strip of metal. 
     It is therefore a feature of a least one embodiment of the invention to permit construction of all of the elements of the tab-form terminal from a single metal strip. 
     The embossments may extend along the width by only a portion of the width. 
     It is therefore a feature of a least one embodiment of the invention to provide greater stiffness to the blade of the tab-form terminal by preserving unformed portions around the embossments. 
     At least some of the embossments are centered within the width. 
     It is therefore a feature of a least one embodiment of the invention to provide a relatively continuous conductive surface on the outer edges of the tab-form terminal such as contact the receptacle. 
     The bend diameter may be substantially equal to the thickness of the strip. 
     It is therefore a feature of a least one embodiment of the invention to permit the formation of the tab-form terminal from low ductility materials that will not tolerate zero-radius bends. 
     The bend may terminate at opposed notches in the strip providing a chamfer at an unsupported end of the blade. 
     It is therefore a feature of a least one embodiment of the invention to reduce the necessary bending force while providing a guiding chamfer on the tab. 
     At least one embossment maybe positioned to interact with a detent on the receptacle holding the blade in the receptacle. 
     It is therefore a feature of a least one embodiment of the invention to permit the same embossments used for spacing to provide a detent against disengagement of the tab-form terminal and the receptacle. 
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of the terminal blade of the present invention aligned for receipt by a standard quick connect receptacle; 
         FIG. 2  is a perspective view of a metal strip as prepared before bending into the terminal blade of  FIG. 1 ; 
         FIG. 3  is a side elevational view of the metal strip of  FIG. 1  after folding into the terminal blade; 
         FIG. 4  is a simplified perspective view in phantom of a switch having flexible contact carriers terminating in terminal blades per the present invention. 
     
    
    
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1 , a terminal blade  10  of the present invention provides a generally planar tab having a front face  12  and opposite rear face  14  defining therebetween a tab thickness  16 , in one embodiment being approximately 0.032 inches to conform to that of a standard tab-form terminal and may have, for example, a width of 0.110, 0.125, 0.187, 0.205, or 0.250 inches. The front face  12  and rear face  14  extend along an insertion axis  18  to define a tab length and extend perpendicular to the axis  18  to define a tab width  19  between an upper and lower edge  15  of the blade  10 . 
     The blade  10  may be received by a standard quick-connect receptacle  20 , one example of which has a base  22  whose front surface slidingly receives the rear face  14  there against. An upper and lower edge  24  of the base  22  are rolled to terminate at inwardly oriented rails  26  parallel to a plane of the base  22  and separated from the base  22  by an amount approximately equal to but slightly less than the thickness of the blade  10  forming a channel  17 . Accordingly, when the blade  10  is inserted into the receptacle  20  the upper and lower edges  15  of the blade  10  are guided by the rolled edges  24  and the rails  26  press against the front face  12  to press the rear face  14  of the blade  10  against base  22 . The receptacle  20  may have a crimp tube  28  permitting it to be electrically joined to a multi-strand wire conductor  30  of a type known in the art. 
     The rear face  14  of the blade  10  may have an extension portion  32  extending along the axis  18  away from the direction in which it is received by receptacle  20  to provide a means for electrical connection between the blade  10  to an associated electrical device or circuit. A wire (not shown) may be spot welded to the extension portion  32  or crimped to the extension portion  32  by tab  31 . 
     Referring now also to  FIG. 2 , the blade  10  may be constructed from a single metal strip  34  of an electrically conductive material such as a phosphor bronze, brass or beryllium copper, and may have a width  19 ′ substantially equal to the width  19  of the finished blade  10  and extending between edges  15 ′ of the strip  34 . Generally a length of the strip  34  will be no less than twice the length of the blade  10  and the strip  34  may have a thickness  21 , for example, of 0.008-0.012 inches in thickness. The thickness  21  of the strip  34  will be less than half the thickness  16  of the blade  10  and preferably approximately one third of that thickness of the blade  10 . 
     In forming the blade  10 , the strip  34  will be folded back along itself along a bend line  38  crossing the width  19 ′ and dividing a first end  40  of the strip  34  into a first portion  42  as will form the front face  12  of the blade  10 , and a second portion  44  as will form the rear face  14  of the blade  10  and extension portion  32 . V-shaped notches  45  may be cut in the edges  15 ′ of the strip  34 , their vertices providing endpoints of the bend line  38  to facilitate the bend and provide a corresponding chamfer  46  (shown in  FIG. 1 ) on the leading edge of the blade  10  assisting in the guidance of the blade  10  into the receptacle  20  by providing a slightly sharpened leading edge of the blade  10 . This chamfer  46  is augmented by a chamfer-like edge provided by the outer bend radius of the strip  34  at the bend line  38 . 
     Referring now to  FIGS. 2 and 3 , inner faces  47  of the portions  42  and  44  (as will be opposed when the strip  34  is folded into the blade  10 ) may include embossments  48   a - d  extending outward (upward as depicted) from the inner faces  47 . In this embodiment, the portion  42  has two embossments  48   a  and  48   b  extending a portion of the width  19  of the strip  34  and having a raised height  50  defining the separation of the inner faces  47  of the portions  42  and  44  when they are folded together to form the blade  10  as depicted in  FIG. 3 . The embossments  48   a  and  48   b  are centered between the edges  15 ′ of the strip  34  so as to provide a substantially planar margin  52  to the front face  12  (shown in  FIG. 1 ) such as will receive pressure from the rails  26 . In contrast, embossments  48   c  may extend inward from edges  15 ′ to provide a planar gap  54  (shown in  FIG. 1 ) between them. The use of both types of embossments represented by embossments  48   a  and  48   c  provide improved separation stabilization of the portions  42  and  44  against torsion about the axis  18 . Generally, the embossments  48   a - d  support the portions  42  and  44  presenting front face  12  and rear face  14  to remain parallel under compression. 
     An additional embossment  48   d  may be formed in the inner face  47  of the portion  44  that will become the rear face  14  positions to lie between embossments  48   a  and  48   b  when the strip is folded to the form of the blade  10  as shown in  FIG. 3 . The embossments  48   a - d  may have a rounded form to prevent tearing of the metal of the strip  34  and yet in combination provide stable support. 
     Referring momentarily to  FIGS. 1 ,  2  and  3 , embossment  48   d  may be positioned so as to interact with a detent portion  60  formed in the base  22  of the receptacle  20  to prevent disengagement of the receptacle  20  and blade  10 . 
     Additional longitudinal embossments  58  may be placed in the portion  44  of the strip  34  that forms the extension portion  32  to provide for stiffening of a conductor portion of the strip  34  attached to the blade  10  which comprises only a single thickness of material. The longitudinal embossments  58  may, for example, be in a length of the extension portion  32  anchoring the blade  10  to a housing or the like. These longitudinal embossments  58  extend generally along the length of the strip  34  and may be inward or outwardly facing. 
     The embossments  48   a - d  may be formed by a stamping operation performed on the blank of the strip  34  and the notches  45  cut by a punching operation. Generally these operations may be conducted in tandem and produce very little waste. It will be understood that the embossments may be given different orientations and positions from those shown to comport with different receptacles and the contact areas associated with those receptacles or for reasons of manufacturing convenience. 
     Referring now to  FIG. 4 , the extension portions  32  may provide not only for electrical conductors (being practical because of the reduced material thickness) but may also provide flexible carrier strips for electrical contacts  62  in an electrical switch. In this case, the electrical contacts  62  may be supported at cantilevered ends of the extension portions  32  to switchably engage opposing contacts  64  mounted on stationary elements  66  when the extension portions  32  are flexed by an operator  68 . In this application, a portion of the extension portion  32  (for example that containing longitudinal embossments  58  shown in  FIGS. 2 and 3 ) may be embedded in a housing wall  70   
     Referring to  FIG. 3 , it will be understood that the present invention permits the formation of the blade  10  from a spring-like material suitable for holding electrical switch contacts, in part, because of the large bending diameter  57  enabled by the embossments  48   a - d . The embossments  48   a - d  together define the separation of the inner faces  47  which substantially equals the bending diameter  57  which, in a preferred embodiment, will be approximately one-third of the thickness  16  of the blade  10 . By increasing the bending diameter  57  to above the “zero radius” (i.e., zero diameter) bend often used in the industry, a stiffer and less ductile material may be used for the strip  34  eliminating the need to mechanically attach a separate material to the blade  10  for contact supports. 
     Variations and modifications of the foregoing are within the scope of the present invention. It is understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     Various features of the invention are set forth in the following claims.