Abstract:
A multipole pin strip, comprising a body having a back, a plurality of electric pin contacts projecting from the back of the body, a pin contact holder located adjacent the back of the body and receiving the electric pin contacts therethrough, and the electric pin contacts being bent down on a back of the pin contact holder is disclosed

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of German Patent 10 2006 026 104.6 of Jun. 3, 2006. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a pin strip, in particular, to a multipole pin strip for an engine control unit. 
       BACKGROUND 
       [0003]    A consequence of electrical component density currently achievable on printed circuit boards is that the conductor tracks on the circuit board that are used to bring in grounding connectors and signaling lines must also have high density. Connectors of components of printed circuit boards are also subject to these high density requirements. Thus, pin strips with 400 to 800 pin contacts per 100 mm edge length are now required. Due to the resultant high pin density involved, the problem arises that if individual pins or electrical pin contacts are not precisely enough aligned with each other, mounting on the circuit board or connecting a connector jack to the connector or the pin strip is difficult or altogether impossible. This may lead to an erroneous electrical contact when mounting the pin strip on a circuit board, or the pin contacts may not be inserted precisely enough into the corresponding openings of a connector jack. In the latter case, a problem is that while non-centric plugging together may establish a correct electrical contact, it can lead to failure of such electrical connection later on. In the former case, a problem encountered during processing of multipole pin strips is to reliably produce the requisite tolerances on one solder side of the electric pin contacts in order to connect the pin strip electrically to and properly bonding to a circuit board. 
       SUMMARY 
       [0004]    The invention relates to a multipole pin strip, comprising a body having a back, a plurality of electric pin contacts projecting from the back of the body, a pin contact holder located adjacent the back of the body and receiving the electric pin contacts therethrough, and the electric pin contacts being bent down on a back of the pin contact holder. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0006]      FIG. 1  is an oblique partially exploded view of a partially assembled body of a multipole pin strip according to the present invention; and 
           [0007]      FIG. 2  is an oblique partially exploded view of the multipole pin strip of  FIG. 1  in a partially mounted state. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0008]    The invention is explained in greater detail in the following on a 181-pole pin strip for a printed circuit board of an engine control unit. However, the invention is not to be limited to such a multipole pin strip but generally comprises pin strips requiring narrow tolerances of electric pin contacts. This applies in particular to the size of a wobble circle of a back free end of each electric contact of the pin strip. 
         [0009]      FIG. 1  shows an embodiment of a body  100  as it emerges from an injection-molding process in an injection-molding machine. The body  100  may be molded around electric pin contacts  110 . For the sake of clarity, a great number of pin contacts  110  are omitted in  FIG. 1  or offset electric pin contacts  110  in the foreground of  FIG. 1  are shown in exploded view. In the production of pin strip  1  (see  FIG. 2 ) not necessarily all pin contacts  110  need be molded into the body  110  but can partially or even entirely be provided in it by stitching. 
         [0010]    The electric pin contacts  110  of pin strip  1  in accordance with the invention may each be formed for instance at both their free end sections as pin, tab, and/or jack contact. This may allow, depending on requirements, a mating connector (connector jack) to be pushed onto pin strip  1  or the free ends  118  of pin contacts  110  to be bonded on a back  101  of body  100 . These free ends  118  may be soldered to conductor tracks of a printed circuit board and are then appropriately formed as pin contacts. 
         [0011]    Body  100  may be constructed essentially as a cuboid, with pin contacts  110  being provided permanently connected with body  100  in a continuous central or lateral wall of this cuboid. The arrangement of pin contacts  110  in body  100  depends on the technical requirements of pin strip  1 , with pin contacts  110  being preferably provided in a matrix arrangement in body  100  made up of a multitude of lines and a multitude of gaps. This is achieved by inlay molding and/or stitching of pin contacts  110 . 
         [0012]    Body  100  has a shoulder  102  that may completely encircle body  100 , which, on the one hand, limits sliding of the mating connector onto pin strip  1 , and on the other hand, provides a locking or stopping device  104  for the mating connector. In the present example, stopping device  104  is a boring through shoulder  102  with which the mating connector can be fastened to body  100  of pin strip  1 . 
         [0013]    Body  100  also comprises on its back  101  a receiving device  106  which covers a center section of pin contacts  110 , at least on one side. The receiving device  106  which encircles, at least partially, the entirety of electric pin contacts  110  may be provided on body  100 . If receiving device  106  is provided around all pin contacts  110  it has on one underside a recess (negative z-direction) to allow the free ends  118  or free end sections  116  of pin contacts  110  to be bent down and to bond electrically with the printed circuit board. Receiving device  106  can receive a pin contact holder  200  that is shown outside body  100  in  FIG. 2  (discussed infra). 
         [0014]    Body  100  comprises a leg  107 , positioning pin  108 , and bush  120 , allowing it to be positioned and fixed on the circuit board. Positioning pin  108  may be provided on receiving device  106 , but alternatively, may be also be provided on shoulder  102  or the body  100  itself. This may also be realized in a statically reversed arrangement. Leg  107  may be provided on device  106 , but alternatively, may also be provided on shoulder  102  or on body  100  itself. In the embodiment shown, leg  107  is a plastic catch that has a clearance into which a press fit bush  120  is inserted. However, in an alternative embodiment, a component other than a bush  120 , such as a screw or a rivet, may be inserted in the clearance, thereby fixing pin strip  1  to the circuit board. Press fit bush  120 , may be made of metal and serves to stop leg  107  (plastic catch) with clearance from yielding when permanently connected with the circuit board. In the embodiment shown, positioning pin  108  is for insertion into a hole of the circuit board. It is of course also possible to provide the leg  107  shown with a different means for engaging the circuit board. Thus, it is possible for example, to lock it or to directly screw it into pin strip  1  with a screw coming from the underside of the circuit board. Positioning pin  108  and leg  107  may both be provided on the same plastic catch for an accurately fitting connection with the circuit board. Body  100  may also comprises an inserted or pressed-in bush  130  on receiving device  106  into which a cover for body  100  can be fixed. Such fixing may be accomplished by means of a screw cutting into metal bush  130 . 
         [0015]      FIG. 2  shows the almost completely assembled 181-pole pin strip  1 , with four electric pin contacts  110  illustrated in exploded view. In the illustration of  FIG. 2  the pin contact holder  200  is not shown in assembled position on body  100  but in an exploded position, so that pin contact holder  200  is easier to see. In assembled position, the pin contact holder  200  sits on body  100  in its receiving device  106 . Pin contact holder  200  may be permanently connected with body  100 . This may be accomplished by means of locking pin contact holder  200  together with body  100  or receiving device  106 . 
         [0016]    For purposes of mounting pin contact holder  200  on body  100 , it is threaded onto pin contacts  110  before they are bent downwards and is moved forwards toward body  100 , with pin contact holder  200  being subsequently fixed on body  100 . Electric pin contacts  110  are then bent downward, possibly at a 90° angle. However, it is not necessary to bend pin contacts  110  at a right angle and depending on the application, they may be bent at a different angle. 
         [0017]    Pin contact holder  200  is preferably constructed essentially cuboid and comprises a number of channels  210  in transverse direction through which pass electric pin contacts  110  in the assembled state of pin contact holder  200 . A channel  210  for each pin contact  110  is formed in pin contact holder  200 . Each channel  210  guides the respective pin contact  110  as tightly as possible so that it has the smallest possible freedom to move within channels  210 . This is achieved with a clearance fit, preferably a tight clearance fit or in particular with a transition fit. The dimension of fit reaches its limits where the pin contact holder  200  can no longer be pushed onto electric pin contacts  110  without damaging a pin contact  110  and be moved forward towards body  100 . 
         [0018]    Freedom to move of each pin contact  110  is restricted by channels  210 , so that a resultant wobble circle of each free end  118  of each pin contact  110  is smaller than that without using the pin contact holder  200 . In particular, pin contact holder  200  positions pin contacts  110  in the z-direction, thereby reducing the free length and distortion of pin contacts  110  in the y-direction. This also results in smaller tolerances of projections of pin contacts  110  downward in direction of the circuit board. 
         [0019]    In another embodiment of the invention, not shown in the drawings, the back  201  of pin contact holder  200  is formed such that pin contacts  110  protruding backwards in negative y-direction protrude in front of their angled backwardly free end sections  116  essentially with a same length from pin contact holder  200 . This may apply also solely to part of pin contacts  110 . For this purpose, the back  201  of pin contact holder  200  is stepped or slanted. This means that pin contact holder  200  of  FIG. 2  would be constructed in an upper section (positive z-direction) further backwards in negative y-direction than its lower section. This causes the free ends  118  of pin contacts  110  having longer free end sections  116  to have smaller wobble circles. The extent to which such a slanted or stepped pin contact holder  200  must be used depends on the tolerances required of free ends  118  of pin contacts  110 . 
         [0020]    To further reduce the wobble circles of free ends  118  of pin contacts  110  or to reduce them to almost zero, one or several centering plates  300  centering the respective free ends  118  of pin contacts  110  may be provided below pin contact holder  200 . Centering plate or plates  300  may be connected with a section of receiving device  106  in such a way that this section holds centering plates  300  at least in position. In one mounted position of pin strip  1  on the circuit board the positioning of centering plates  300  on receiving device  106  in engagement with the circuit board can definitively fix these. It is, however, also possible to provide the centering plates  300  fixed on receiving device  106 . Centering plates  300  may be positioned near the positioning means  108  of body  100  on the circuit board and may be near a leg  107  of pin strip  1  on the circuit board. In one embodiment of the invention, all or at least any two of these are located at a single, possibly narrowly delimited point on body  100 . 
         [0021]    Positioning of centering plate  300  on body  100  is realized by way of guide posts  105  and guide holes  305  communicating with each other, whereby in the present example, a guide posts  105  is (a positioning pin and a positioning lug provided on leg  107 ) of receiving device  106 , which engage guide holes  305  of centering plate  300 . In this connection, the positioning pin guide post  105  engages in a corresponding guide hole  305  in centering plate  300  while the positioning lug guide post  105  engages a separate corresponding guide hole  305 . It is, of course, also possible to provide only one guide post  105  or only one guide hole  305  on centering plate  300 . 
         [0022]    Centering plate or plates  300  has/have several apertures  318  through each of which extends one backward free end section  116  of a pin contact  110 . This aperture  318  additionally limits the freedom to move of each free end  118  or each free end section  116  of each electric pin contact  110 . Apertures  318  may be formed as centering clearances which have a tapering diameter or tapering internal dimensions. Such apertures  318  may be, for example, semi-spherical, conical, or pyramidal in shape on the inside. Here, each free end  118  has to pass through the larger diameter or lager dimensions of apertures  318  in the direction of insertion of a free end  118  through the apertures  318 , and as the free end  118  is moved further forward, it centers itself automatically within the aperture  318 . The smallest diameter or the smallest dimensions of apertures  318  correspond(s) approximately to the corresponding section of each pin contact  110  in this area. This in turn can be achieved through a clearance fit, a tight clearance fit, or a transition fit. The size of such fit depends on whether a free end section  116  of a single pin contact  110  fails to move with it upwards, for example, gets stuck when the centering plate  300  is pushed on. When the centering plate  300  is pushed onto the body  100  the pin contact free end  118  concerned is taken up by a comparatively large centering aperture  318  diameter and centered by the reducing centering aperture  318  diameter. This ensures that the free ends  118  of the electric pin contacts  110  are precisely positioned. 
         [0023]    After positioning centering plate  300 , it can be locked on body  100  or it can find its final position during mounting of body  100  on the circuit board. Thereafter the free ends  118  are soldered to the respective conductor tracks or circuit board pads of the printed circuited board. 
         [0024]    By providing an improved pin strip  1  as described above, in particular an improved multipole pin strip  1  whose electrical strip contacts  110  are aligned such that narrow tolerances can be realized with them. This is to apply in particular to a section on the circuit-board side of a multipole pin strip  1  whose electric pin contacts  110  are soldered to a circuit board. 
         [0025]    The body  100  as described above, restricts the freedom to move of the free ends  118  of the electric pin contacts  110  is restricted such that they comply with the necessary tolerances. In particular with multipole 90° pin strips  1  where electric pins or tabs are inlay-molded, thus giving a substantial free length of pin or tab, the large tolerances of the pin or tab projections are reduced. This applies in particular to the free ends of electric pin contacts  110  to be bonded with the circuit board. The wobble circles of the free ends  118  of electric pin contacts are thereby markedly reduced. The tolerance for the free ends  118  of electric pin contacts  110  lying opposite in the body is also reduced by the pin contact holder in accordance with this invention. This depends in particular on a length of the bearing of each electric pin contact  110  in the body  100 . 
         [0026]    After inlay-molding or molding-on of the body  100  and a possible stitching of electric pin contacts  110 , the body  100  is pushed onto the electric pin contacts  110  in stitch direction before they undergo bending and preferably locked with the body  100 . 
         [0027]    The pin contact holder  200  has for each pin contact  110  one channel  210  which positions the pin contact  110  in one direction corresponding to a vertical direction of the unbent pin contact sections  116 . This also reduces a free length and distortion of the pin contacts  110  after bending of the pin contacts  110  in stitch direction. In addition, the pin contact holder  200  also results in positioning of the pin contacts  110  in a direction along the pin contact holder  200  (turned at a 90° angle in relation to a plugging direction of a connector jack onto the pin strip  1  in accordance with the invention), so that the wobble circles of the pin contact free ends are altogether markedly smaller compared with the state of the art. Also, by providing the pin contact holder  200  in accordance with the invention the tolerances of the pin contact projections are reduced. The back of the pin contact holder  200  may be stepped. Providing the pin contact holder  200  on the body  100  also results in a simplified bending of the electric pin contacts  110  which thereby have a shorter projection for subsequent soldering to the circuit board conductor tracks. 
         [0028]    Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.