Patent Publication Number: US-6217379-B1

Title: Plug-in contact

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a plug-in contact produced as a single piece from a metal strip, comprising a pin-shaped contact part and a connecting part for connecting an electric line. 
     2. Description of the Related Art 
     Plug-in contacts with a crimped terminal for the line to be connected are generally known. Pin-shaped plug-in contacts, i.e. plug-in contacts with a pin- or needle-shaped contact part are also known. The connecting line is increasingly also being connected by a crimp connection. 
     In particular, the pin-shaped plug-in contacts with small pin cross-sections of, for example, about 0.4 mm 2  were formerly usually produced from step-milled strip or in two parts from a solid pin and a connecting part for the electric line connected thereto, produced from sheet metal. This mode of production involves considerable expenditure in terms of time and/or material, but this is considered to be justified in view of the security of plugging and the flexural strength required. Owing to the possibility, normally required, for installation in plug housings, known plug-in contacts also have to be provided with additional catch marks and other fixing aids so that they maintain their position permanently once installed. 
     Starting form this state of the art it is an object of the present invention to provide a plug-in contact of the type mentioned at the outset which is easier to produce with equal reliability of operation. 
     SUMMARY OF THE INVENTION 
     According to the invention, this object is achieved by the characterising features of claim  1 . 
     The sub-claims relate to further advantageous configurations and developments of the invention. 
     It is accordingly proposed according to he invention that a guide part is arranged between the contact part and the connecting part, in that the guide part is configured in the shape of a box with a triangular cross-section and in that a flat side of the guide part is arranged at a distance parallel to the original lane of the strip. 
     A defined orientation of the plug-in contact in the case of the proposed installation in a plug housing can be achieved with the proposed triangular geometry of the guide part. 
     According to an expedient configuration of the plug-in contact produced form flat material, the guide part is formed by two lugs which are each angled at a first angle along the centre line of the original metal strip, which lugs are bent symmetrically to one another at a second angle so that their longitudinal edges abut and form a covering face. 
     The plane covering face opposes the original strip plane of the sheet metal strip used for this purpose and extends parallel thereto. This pronounced shaping of the guide part gives the plug-in contact high rigidity owing to work-hardening, so that the necessary material cross-section can be kept small for reasons of strength. 
     In a preferred configuration of the plug-in contact, the first angle is between 60° and 120°, preferably 120°, and the second angle is 30° to 60°, preferably 30°, in each case. 
     In a further improvement of the invention, the plug-in contact is characterised in that the guide part comprises, on the connection side, two lug-shaped projections which serve as a stop. These lug-shaped projections act as a stop for the plug-in contact as it is inserted into the above-mentioned plug-housing so that it is fixed in position therein. 
     To assist this effect, the lug-shaped projections can advantageously be offset form the box part of the guide part. 
     According to a configuration of the invention, the pin-shaped contact part is formed by two partial lugs which are roughly identical in cross-section, which are bent symmetrically round 180° along the longitudinal axis and, resting tightly against one another, form a closed cross-section. A tip is worked at the leading end of the contact part. The plug-in contact has a common bending line which extends from the tip to the connecting part, so that bending is considerably simplified in comparison with other plug-in contacts. 
     In a further configuration of the invention, the box part located between the contact part and the connecting part comprises a one-sided recess opposite the original plane of the strip. 
     This recess is arranged about half way along the guide part. The end faces of the recess can also preferably be limited at least on the connecting side by first tongues which are angled downwardly from the lugs, forming the covering face, of the box parts remaining. 
     In a development of the invention, the end face of the box part facing the pin-shaped contact part can likewise be limited by two second tongues of identical cross-section at the transition to the contact part, the first and second tongues being configured in the manner of rails or shovels and serving similarly to a shoe horn as an entry aid during insertion and interlocking of the plug-in contact into a plug housing. 
     To fix the plug-in contact according to the invention more securely in the plug housing, the front edge, facing the recess in the guide part, of the leading contact part adjacent to the contact part is provided as a stop edge for interlocking with a plug housing into which the plug-in contact is inserted. It is held non-positively and positively therein. 
     The plug housing provided for the plug-in contact according to the invention is characterised, in particular, that is receives at least one plug-in contact, but preferably a plurality of plug-in contacts and in that each proposed plug-in position comprises a catch projection which interacts with the associated plug-in contact. This plug housing is preferably configured as a so-called pin connector housing with plug-in positions arranged side by side for plug-in contacts. 
     This and further advantageous configurations and improvements of the invention will be illustrated and described in more detail with reference to the embodiments illustrated in the schematic drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a plug-in contact according to the invention; 
     FIG. 2 is a segmentary longitudinal section through a plug housing, intended to receive plug-in contacts, with two plug-in contacts inserted therein, 
     FIG. 3 is across-section through the contact piece along section line III—III, and 
     FIGS. 4 a  to  4   d  are various views of a further embodiment of a plug-in contact. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a plug-in contact  10  according to the invention in an oblique view from above so that its essential features can be seen. 
     At its front, the slim plug-in contact  10  possesses a pin-shaped contact part  12  which is connected to a centrally arranged guide part  14  having a triangular cross-section which can be seen in the sectional view in FIG. 3. A connecting part  16  which is configured in a known manner as a crimp connection and is connected to a conductor  18  in the example illustrated is attached to the guide part  14 . 
     According to the invention, the plug-in contact  10  is produced in one piece as a stamped and bent part from a metal strip, the width of the metal strip being determined by the material requirement or the guide part  14 . About half way along, this guide part  14  possesses a recess  20  which extends about half way up, is about one third of the length of the guide part  14  and divides the box-shaped guide part  14  into a leading and trailing guide box  14 . 1 ,  14 . 2 . 
     An elastic catch projection  24  shaped on the associated plug housing  22  shown in FIG. 2 in the manner of a leaf spring on a housing web  23  engages positively in this recess and is thus fixed securely therein so that the plug-in contact  10  is fixed in its position. 
     To assist this positive engagement during assembly, the recess  20  is covered by angled first and second tongues  26 ,  27  at the rear end facing the connecting part  16  similarly to the guide part  14  at the transition to the contact part  12 , the second tongues additionally also acting as an axial stop. The opposing limiting edge of the recess  20  serves as a stop edge  28  for the catch projection  24 . 
     The housing web  23  on which the resilient catch projection  24  is shaped possesses a catch edge  30  which is at an angle to the plug-in contact and interacts with stop lugs  32  shaped for this purpose on the plug-in contact  10  in the transition region of the guide part  14  to the connecting part  26 . 
     All three portions, in other words the contact part  12 , the guide part  14  and the connecting part  16  of the plug-in contact  10  according to the invention have the common feature that they are bent upwards from the original plane of the strip. 
     The front, in other words the pointed contact part  12  located on the contacting side is produced from a portion of the metal strip which is narrower than the guide part  14 , similarly to a part of the connecting part  16 , whereas the guide part has the greatest width in the developed view. 
     The pin-shaped contact tip  12  is bent symmetrically upwardly round 180° along the centre line from two lugs of equal width, so that the two lugs rest against one another in parallel without spacing. The contact part  12  is pointed at the front according to the prior stamping. 
     As mentioned, the guide part  14  is box-shaped in design and possesses a cross-section of an equilateral triangle with the tip of the triangle in the original plane of he strip and with the base opposite. The sides issuing from the tip of the triangle enclose an angle of about 120°, whereas an angle of about 30° is enclosed between the sides in each case and the base. As shown in FIG. 1, the pin-shaped contact tip and the guide part have a common bending line which considerably simplifies the production process for the plug-in contact. 
     As already mentioned, the connecting part  16  is configured in a known manner as a crimp connection with a conductor connection  16 . 1  and an insulating connection  16 . 2 . The conductor connection  16 . 1  interacts with the bare conductor wire which is clamped and therefore contacted here, whereas, in the insulating connection  16 . 2 , the insulated conductor is surrounded and clamped in the insulated region. 
     A further example of a plug-in contact according to the invention is shown in various views in FIGS. 4 a  to  4   d . The known reference numerals again represent the above-described parts. In contrast to the above-described embodiment, the first and second tongues  26 ,  27  are absent from the plug-in contact according to FIGS. 4 a  to  4   d  (cf., in particular, FIG.  1 ). 
     The dimensional details in FIG. 4 a  show the possible size of the plug-in contact. For example, it can have a length of 24.4 mm. The perspective view in FIG. 4 d  shows the common bending line B through the plug-in contact and the at least approximately triangular cross-sectional shape of the guide part  14 .