Patent Abstract:
The invention relates to an electrical pin contact, ( 1, 32, 56 ), having a connecting part ( 2 ) and a connector tongue ( 4 ) together with a locking part ( 3, 33, 57 ). A separate locking spring ( 14, 34, 58 ), is provided which is inserted into the locking part ( 3, 33, 57 ) perpendicularly to the longitudinal axis of the contact ( 1, 32, 56 ). Particularly simple mounting of the locking spring ( 14, 34, 48 ) is achieved in that the latter has latching means, which fix the locking spring ( 14, 34, 58 ) in position in the locking part ( 3, 33, 57 ) through insertion of the locking spring into the locking part ( 3, 33, 57 ).

Full Description:
FIELD OF THE INVENTION 
     The invention relates to an electrical contact, in particular according to the precharacterising clause of claim 1. 
     BACKGROUND OF THE INVENTION 
     European patent EP 0 762 551 describes a pin contact with a connecting part, a connector tongue, and a locking part. The locking part has a separate locking spring which may be inserted perpendicularly to the pin contact into the locking part. The connector tongue and the locking part are plugged into a mating counterpart and fixed in position therein by the locking spring. 
     Such pin contacts are conventionally stamped and formed from sheet metal blanks which provides good bending characteristics for cable clamping and which exhibits good electrical conductivity. Such metal is as a rule less usable as a spring material due to a lack of resilience and strength. A compromise material is not capable of fulfilling either requirement optimally. 
     In EP 0 762 551, a locking spring made from a different suitable material from the pin contact is used. The locking spring is connected with the pin contact using a two part format. Such two-part pin contacts are more expensive to produce than one-part pin contacts. This is because it is necessary to stamp and form two separate components from different materials and to assemble and clamp them together. Assembly and clamping is particularly costly. Moreover, clamping requires more complicated tools, which are not only expensive but also unreliable. 
     Mounting the locking spring in the direction perpendicular to the connector tongue, as in the European specification recited above, constitutes a considerable simplification relative to the method of sliding one of the two components axially into the other and clamping them together. However, even with the solution proposed in EP 0 762 551, it is still necessary to clamp the two components together to fix the locking spring in the locking part, which is correspondingly costly and time-consuming. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a pin contact made stamped and formed from a steel sheet with a separately produced locking spring which is economic to produce and mount. 
     This object is achieved by the features of claim 1. Because the locking spring has latching means, which fix the locking spring in position through insertion thereof into the locking part, the locking spring may be mounted merely by plugging it into the locking part. Clamping of the components is unnecessary, whereby complicated, time-consuming operations may be eliminated. Because the locking part has openings adapted for insertion and latching of the locking spring, the locking spring mounting process is simplified. 
     The locking spring may have guide surfaces which contribute to the simplification of locking spring mounting. Latching of the locking spring at its ends makes its connection with the locking part strong. 
     In order to facilitate mounting a first guide surface, preferably folded at right angles, may be arranged in the area of the rear end of the locking spring on each side thereof. In this way, the locking spring is guided at one end over the entire mounting path. 
     Handling of the locking spring is also improved. A latching means is provided at least on one of the two first guide surfaces. The latching means cooperate with the openings in the top of the locking part to limit rebound of the locking spring or prevents buckling thereof. The force required to tear the contact out of the chamber is thereby increased. 
     In various embodiments the latching means may take the form of a channel on the lower edge of a first guide surface or of a hook on a rear edge of a different first guide surface or of a perforation pocket or perforation tongue, which is arranged on the outside of a further first guide surface. The solution using the hook at the lateral edge of the different first guide surface is particularly favourable from a manufacturing perspective. 
     It is advantageous for the locking spring to have an obtuse-angled first folded portion and an obtuse-angled second folded portion in the area of its front end and for there to be arranged on each side of the obtuse-angled first folded portion a second guide surface folded inwards at right angles. The second guide surface has upper corners bent slightly outwards, which upper corners lie against an inner surface of the top or against an upper side of a side opening in the locking part after latching of the locking spring. The second guide surfaces simplify mounting of the locking spring at the other end thereof. The upper corners effect secure latching thereof in the locking part, wherein latching is reinforced by tensile loading of the locking spring. 
     An advantageous construction of the invention has an alternate locking spring which has a different obtuse-angled first folded portion, a right-angled second folded portion and an obtuse-angled third folded portion in the area of its different front end. A perforation tongue which is directed towards the connecting part is provided in the obtuse-angled third folded portion. The perforation tongue lies against the different inner surface of a different top of a different locking part after latching of the different locking spring. In this embodiment, the different end of the different locking spring may be produced in a particularly simple manner merely by three folded portions, since the outer edges thereof serve as guide surfaces. In this embodiment, tensile loading of the different locking spring reinforces latching. 
     In another embodiment, a further locking spring comprises a further obtuse-angled first folded portion, a further right-angled second folded portion and a further obtuse-angled third folded portion in the area of its further front end and in that a further second guide surface folded at right angles is arranged on each side of the further obtuse-angled first folded portion. A free end of the further obtuse-angled third folded portion lies against the further inner surface of a further top of a further locking part after latching-in of the further locking spring. The further second guide surfaces folded at right angles serve simultaneously to fix the locking spring in position in the longitudinal and transverse directions of the pin contact. 
     It may also be advantageous for the connector tongue to have two halves of arched cross section each with a tip, wherein the two halves adjoin at their edges and are at least pressed and/or welded together at their tips. In this way, the bending strength of the connector tongue is increased and the thickness thereof necessary for good electrical contact is achieved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a pin contact having a connecting part, a locking part and a connector tongue, a locking spring is exploded from the locking part. 
     FIG. 2 is a perspective representation obliquely from the rear of the pin contact of FIG. 1, the locking spring is exploded from the locking part. 
     FIG. 3 is a perspective representation obliquely from the rear and above of the pin contact of FIG. 1, with the locking spring mounted in the locking part. 
     FIG. 4 is a longitudinal section through the locking part of the pin contact of FIG. 1, with the locking spring mounted thereon. 
     FIG. 5 shows a cross section of the locking part taken along line D-D of FIG.  4 . 
     FIG. 6 shows a cross section of the locking part taken along line E-E of FIG.  4 . 
     FIG. 7 is a bottom view of the pin contact of FIG.  1 . 
     FIG. 8 is a side view of the pin contact of FIG. 1, with the locking spring mounted thereon. 
     FIG. 9 is a top view of the pin contact of FIG. 1, with the locking spring mounted thereon. 
     FIG. 10 is a view of two stamped blanks for the pin contact of FIG.  1 . 
     FIG. 11 is a perspective view of a second embodiment of a pin contact having the connecting part, a second locking part and the connector tongue, a second locking spring is exploded from the second locking part. 
     FIG. 12 is a perspective representation obliquely from the rear of the second pin contact of FIG. 11, the second locking spring is exploded from the second locking part. 
     FIG. 13 is a perspective representation obliquely from the rear and above of the second pin contact of FIG. 11, with the second locking spring mounted in the second locking part. 
     FIG. 14 is a longitudinal section through the second locking part of the second pin contact of FIG. 11, with the second locking spring mounted thereon. 
     FIG. 15 shows a cross of the second locking part taken along line D-D of FIG.  14 . 
     FIG. 16 shows a cross section of the second locking part taken along line E-E of FIG.  14 . 
     FIG. 17 is a bottom view of the second pin contact of FIG.  11 . 
     FIG. 18 is a side view of the second pin contact of FIG. 11, with the second locking spring mounted thereon. 
     FIG. 19 is a top view of the second pin contact of FIG. 11, with the second locking spring mounted thereon. 
     FIG. 20 is a view of two stamped blanks for the second pin contact of FIG.  11 . 
     FIG. 21 is a perspective view of a third embodiment of a pin contact having the connecting part, a third locking part and the connector tongue, third locking spring is exploded from the third locking part. 
     FIG. 22 is a perspective representation obliquely from the rear of the third pin contact of FIG. 21, the third locking spring is exploded from the third locking part. 
     FIG. 23 is a perspective representation obliquely from the rear and above of the third pin contact of FIG. 21, with the third locking spring mounted in the second locking part. 
     FIG. 24 is a longitudinal section through the third locking part of the third pin contact of FIG. 21, with the third locking spring mounted thereon. 
     FIG. 25 shows a cross section of the third locking part taken along line D-D of FIG.  24 . 
     FIG. 26 shows a cross of the third locking part, taken along line E-E of FIG.  24 . 
     FIG. 27 is a bottom view of the third pin contact of FIG.  21 . 
     FIG. 28 is a side view of the third pin contact of FIG. 21, with the third locking spring mounted thereon. 
     FIG. 29 is a top view of the third pin contact of FIG. 21, with the third locking spring mounted thereon. 
     FIG. 30 is a view of two stamped blanks for the third pin contact of FIG.  21 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2 are perspective views of a pin contact  1 . The pin contact  1  serves to connect electrical conductors, not shown. As best shown in FIGS. 1 and 2, pin contact  1  has a connecting part  2 , a locking part  3  and a contact part constructed as a connector tongue  4 . The connector tongue  4  and the locking part  3  are plugged into a mating counterpart (not shown), in order to produce the desired electrical connection. 
     A stripped electrical conductor (not shown) is attached in the area of the connecting part  2 . In the present example, crimping claws  5  are used for this purpose. However, a soldered connection or a plug part or the like may be used instead. 
     While the connecting part  2  is open at the top prior to closure of the crimping claws  5 , the adjacent locking part  3  exhibits a closed, rectangular box section. A first side wall  7  and a second side wall  8  are folded upwards at right angles from a base  6 . A top  9  is folded horizontally from the first side wall  7  and is butt-welded to the second side wall  8 . The base  6 , the side walls  7  and  8  and the top  9  together form the locking part  3 . 
     One half  10 ,  11  of the connector tongue  4  is connected with each of the base  6  and the top  9 . The halves  10 ,  11  exhibit arched cross sections, which form a lenticular cavity when the halves  10 ,  11  are put together. The increased thickness of the connector tongue  4  promotes the rigidity thereof. The tips  12 ,  12 ′ of the halves  10 ,  11  are latched and/or welded together by a tongue and groove arrangement. 
     Above the locking part  3  of FIGS. 1 and 2 there is illustrated a locking spring  14 . The locking spring  14  is shown above the locking part  3  for ease of explanation. The locking spring  14  is oriented as if it were mounted in the locking part  3 . 
     A rectangular first opening  15  is provided in the top  9  of locking part  3 , through which the locking spring  14  is perpendicularly inserted. In the second side wall  8  there is provided a rectangular side opening  16  with an upper side  30 , which serves to latch in the locking spring  14  (see also FIGS.  6  and  8 ). An extension  28  of the second side wall  8  projecting above the top  9  serves in angular orientation of the pin contact  1  in a counterpart and in protecting the locking spring  14 . In the base  6  there is arranged a perforation pocket  17  (FIGS. 4,  5 ,  6 ,  7 ), which is used to fix the locking spring  14  in the longitudinal direction of the locking part  3 . 
     In the area of a rear end  18  of the locking spring  14  there is arranged, on each side thereof, a first guide surface  19 ,  19 ′ folded at right angles. At the lower edge of the first guide surface  19  there is provided a channel  20 , which, when the locking spring  14  is in the installed position, extends parallel to the top  9  and lies against the inner surface  21  thereof. The rear end  18  of the locking spring  14  is thus latched in the locking part  3 . The front edges  22 ,  22 ′ of the first guide surfaces  19 ,  19 ′ extend perpendicularly to the top  9 , whereby the length of the first opening  15  is kept as small as possible. 
     In the area of the front end  23  of the locking spring  14 , an obtuse-angled first folded portion  24  and an obtuse-angled second folded portion  25  are provided. On each side of the obtuse-angled first folded portion  24  there is located a second guide surface  26 ,  26 ′ folded inwards at right angles and having upper corners  27 ,  27 ′ bent outwards slightly. These engage in the locking part  3  after mounting of the locking spring  14  and come to lie against the inner surface  21  of the top  9  or against the upper side  30  of the side opening  16  in the second side wall  8 . In this way, the front end  23  of the locking spring  14  is also latched in the locking part  3 . When the locking spring  14  is subject to tensile load, the latching connection is reinforced by spreading of the bent upper corners  27 ,  27 ′. 
     FIG. 3 shows a perspective representation, obliquely from the rear and above, of the pin contact  1  with an open connecting part  2  and the locking spring  14  mounted in the locking part  3 . The protective function of the extension  28  in relation to the locking spring  14  is clear to see. The same applies to the second pin contact  32  in FIG.  13  and the third pin contact  56  in FIG.  23 . 
     FIG. 4 shows a cross section through the locking part  3  with the locking spring  14  latched or mounted therein. It reveals the top  9  with the first opening  15  for insertion of the locking spring  14  and the base  6  with the perforation pocket  17  as axial limit stop therefor in the direction of the connecting part  2 . In the opposite direction, the locking spring  14  rests with its obtuse-angled first folded portion  24  against the narrow side  29  of the first opening  15 . 
     In addition, FIG. 4 also reveals the channel  20  of the first guide surface  19 , which lies against the inside  21  of the top  9 , and the second guide surface  26 , which rests against the upper side  30  of the side opening  16 . 
     FIG. 5 shows the first side wall  7 , the second side wall  8  with the extension  28 , the base  6  and the top  9 . Furthermore, the first guide surface  19  is shown, with the channel  20 , which, like the upper corner  27 , lies against the inner surface  21  of the top  9 . The perforation pocket  17  in the base  6  is also visible. 
     Referring to FIG. 6, upper corner  27 ′ is positioned in the side window  16  of side wall  8 . As shown, the upper corner  27 ′ engages the upper surface  30  of the side window  16 . Here too, the perforation pocket  17  may be seen. Also visible is the point where the upper corner  27  lies against the inner surface  21  of the top  9 . It is also plain that the corners  27 ,  27 ′ are spread further when the locking spring  14  is subjected to tensile loading and thereby reinforce the latching connection. Similarly, the protective action of the extension  28  relative to the rear end  18  of the locking spring  14  is visible. 
     FIG. 7 is a bottom view of the pin contact  1  showing the base  6  of the locking part  3  having the perforation pocket  17  arranged thereon. As previously described, the pocket  17  cooperates with the locking spring  14  to limit the axial movement of the locking spring  14 . 
     Referring to FIG. 8, the second side wall  8  of the locking part  3  is provided with the side opening  16 , the upper side  30  of which engages the upper corner  27 ′. The end  18  of the locking spring  14  projects only slightly beyond the extension, so that the locking spring  14  is protected, as previously described. 
     As illustrated in FIG. 9, the first opening  15  of the top  9  of the locking part  3  is confirmed to have the locking spring  14  installed therein. The locking spring  14  engages the narrow side  29  of the first opening  15  thereby allowing the locking spring to pivot or swivel as necessary. 
     Two stamped or punched blanks for the pin contact  1  are shown in FIG.  10 . The blanks are connected by a conveying strip  31  and constitute part of a reelable strip of blanks. The part of the blank strip from which the locking part  3  is formed displays the first opening  15 , the side opening  16  and the perforation pocket  17 . 
     The connecting part  2  and the halves  10 ,  11  of the connector tongue  4  are integrally attached to the locking part  3 . At the tip  12  of the upper half  10  of the connector tongue  4  there may be seen a groove  13  and at the tip  12 ′ of the lower half  11  a mating tongue  13 ′, which may be clamped together during assembly of the pin contact  1  and optionally secured by welding. The conveying strip  31  is removed when the connecting part  2  is fitted with a cable. 
     FIGS. 11 and 12 are perspective views of a second embodiment of the pin contact  32 . The locking part  33  and locking spring  34  of the pin contact  32  differ from the locking part  3  and locking spring  14  of the pin contact  1  of FIGS. 1 and 2. Like the locking part  3 , the second locking part  33  has a rectangular cross section, with a top  35 , a base  36 , a first side wall  37  and a second side wall  38 . 
     A first top opening  39 , a second top opening  40  and a third top opening  41  are provided in the top  35 , the openings are dimensioned to receive the locking spring  34  therein. An extension  42 , here of divided construction, is used for angular orientation of the pin contact  32  and for protection of the locking spring  34 . 
     In the area of a rear end  43  of the locking spring  34 , there is arranged on each side thereof a first guide surface  44 ,  44 ′ folded at right angles. At the rear edge of the first guide surface  44 ′ there is provided a hook  45 , which, when the locking spring  34  is in the installed position, extends parallel to the top  35  and lies against the inner surface  46  thereof (see also FIG.  14 ). In this way, the rear end  43  of the locking spring  34  is latched in the locking part  33 . 
     In the area of the front end  47  of the locking spring  34 , an obtuse-angled first folded portion  48 , a right-angled second folded portion  49  and an obtuse-angled third folded portion  50  are provided. The transition between the first, second and third folded portions is preferably radial. The second folded portion  49  is preferably U-shaped, wherein the U shape exhibits a fixed radius of curvature. In the obtuse-angled third folded portion  50  there is arranged a first perforation tongue  51  directed towards the connecting part  2 . The tongue  51  lies against the inner surface  46  of the top  35  of the locking part  33  after the locking spring  34  is latched in position. In this way, the front end  47  of the locking spring  34  is also latched in the locking part  33  and the locking spring  34  is thus secured against unwanted removal. The latching connection is reinforced by spreading of the perforation tongue  51  upon tensile loading of the locking spring  34 . 
     As shown in FIG. 14, second and third perforation tongues  52 ,  53  are offset laterally in the base  36  and are each bent up and inward by 90 20   lengthwise but in opposite directions. The tongues fix the locking spring  34  in the longitudinal direction. The obtuse-angled first and third folded portions  48 ,  50  are clamped in:between the second and third perforation tongues  52 ,  53 . A web  54  in the base  36  (see FIG. 17) between the second and third perforation tongues  52 ,  53  serves to provide perpendicular support of the locking spring  34 . The right-angled second folded portion  49  of the locking spring  34  has an opening  55  (see also FIGS. 11 and 12) which mates with the web  54 . 
     FIG. 15 shows the second side wall  38  with the extension  42 , the first side wall  37 , the top  35  with the inner surface  46  and the base  36  with the second perforation tongue  52 . The components of the locking spring  34  which are visible are the first guide surfaces  44 ,  44 ′ and the obtuse-angled third folded portion  50  with the first perforation tongue  51 . The latter lies against the inner surface  46  of the top  35  when the locking spring  34  is in the mounted state. 
     FIG. 16 shows the third obtuse-angled folded portion  50  with the first perforation tongue  51  and the base  36  with the web  54 . 
     FIG. 18 shows a side view of the different locking part  33  with the second side wall  38  and the extension  42  thereof, which serve in orienting the pin contact  32  and in protecting the locking spring  33 . The first guide surface  44 ′ thereof is likewise illustrated. 
     FIG. 19 shows a top view of the pin contact  32 , with the locking spring  34 , which engages in the first, second and third top openings  39 ,  40 ,  41  of the top  35  of the different locking part  33 . 
     Two stamped or punched blanks for the pin contact  32  are shown in FIG.  20 . The figure shows the second and third perforation tongues  52 ,  53  and the first, second and third top openings  39 ,  40 ,  41 . 
     FIGS. 21 and 22 show a third pin contact  56 , again in perspective positions. It differs from the pin contact  1  and the second pin contact  32  by a modified third locking part  57  and a modified third locking spring  58 . 
     The locking part  57  again exhibits a rectangular cross section, with a top  59 , a base  60 , a first side wall  61  and a second side wall  62  with an extension  78 . 
     A first top opening  63  and a second top opening  64  are provided in the top  59 , which openings are dimensioned to receive the locking spring  58 . 
     In the area of a rear end  65  of the locking spring  58 , there is provided on each side thereof a first guide surface  66 ,  66 ′ folded at right angles. At the rear surface of the first guide surface  66  there is arranged a perforation pocket  67 , the edge  68  of which lies against an inner surface  69  of the top  59  after mounting of the locking spring  58  (see also FIG.  24 ). In this way, the rear end  65  of the locking spring  58  is latched in the locking part  57 . 
     In the area of a front end  70  of the locking spring  58 , an obtuse-angled first folded portion  71 , a further right-angled second folded portion  72  (see FIG. 24) and a further obtuse-angled third folded portion  73  are provided. 
     Two guide surfaces  74 ,  74 ′ are folded back on both sides of the obtuse-angled first folded portion  71 , these being inwardly directed, parallel and rectangular. They project downwards beyond the right-angled, second folded portion  72  and engage, when the locking spring  58  is in the mounted state, in first and second base openings  75 ,  76  in the base  60  (see FIG. 27) as well as in the first top opening  63  and serve to fix the locking spring  58  in the longitudinal direction. 
     FIG. 24 illustrates that, after mounting of the locking spring  58 , the free end  77  of the obtuse-angled third folded portion  73  latches in beneath the top  59  and lies against the inner surface  69  thereof, while the right-angled second folded portion  72  lies against the base  60 . In this way, vertical fixing of the locking spring  58  is ensured and unwanted removal is prevented. 
     As is shown in FIG.  25  and FIG. 26, the edge  68  of the perforation pocket  67  of the first guide surface  66  and the free end  77  of the obtuse-angled third folded portion  73  lie against the inner surface  69  of the top  59  when the locking spring  58  is in the mounted state and thereby effect latching thereof in the locking part  57 . 
     FIG. 26 also shows the second guide surfaces  74 ,  74 ′, which engage in the first and second base openings  75 ,  76  of the base  60  and in the first top opening  63  of the top  59 . 
     The bottom view of FIG. 27 shows the first and second base openings  75 ,  76  in the base  60  of the locking part  57 . 
     The side view of FIG. 28 shows the second side wall  62  with the extension  78  and the second base opening  76  in the locking part  57  together with the locking spring  58 , which is extensively hidden by the protective extension  78 . 
     The plan view of FIG. 29 shows the locking part  57  with the locking spring  58  and the indicated obtuse-angled first folded portion  71  thereof together with the first guide surfaces  66 ,  66 ′. 
     The punched blanks for the pin contact  56  illustrated in FIG. 30 show the locking part  57  with the first and second base openings  75 ,  76  and with the first and second top openings  63 ,  64  prior to forming. 
     In conclusion it may be stated that the pin contacts  1 ,  32 ,  56  are functionally reliable and simple to manufacture and assemble.

Technology Classification (CPC): 7