Patent Document

This is a division of application Ser. No. 09/312,423, filed May 14, 1999 now U.S. Pat. No. 6,178,627. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a method and device for positioning or aligning a printed-circuit board in relation to the die and the anvil of a press, and more specifically a manually operated press for inserting connectors which are provided with so-called press-fit contact pins into a printed-circuit board, referred to below as PCB. 
     For connectors which are provided with press-fit contact pins of this nature to be manually arranged in a PCB, an operation which involves pushing a series of pins simultaneously into a selected corresponding series of holes in the PCB, use is made of a press, which generally comprises a frame which is able to withstand the force between a fixed part and a moving part. 
     The fixed part is generally provided with an anvil, and the moving part, or ram, is provided with an insertion die and this insertion die is always perfectly aligned with the anvil, in other words their centre points always lie on the same vertical insertion centre line. 
     The problem is to adjust the centre point or reference position of the selected insertion zone of the PCB as accurately and quickly as possible with respect to this vertical insertion centre line between die and anvil of the press. 
     Since the press-fit pins of the connectors have to be pushed transversely through the PCB, the anvil is provided with openings, in the form of regularly distributed grooves, which are arranged on the top of the anvil. The distance between these grooves corresponds to the standard distance between the contact pins. 
     The insertion die may either be planar, if the connector can be inserted using a planar die, or may likewise be provided with grooves or pins, if the connector cannot be inserted using a planar die. 
     The problem with a manually operated press of this nature consists primarily in correctly positioning the PCB with respect to the anvil and the insertion die, and more particularly in positioning the holes in the selected insertion zone of this PCP with respect to the grooves in the anvil and, if appropriate, the grooves in the insertion die. 
     This positioning is generally carried out by means of a X-Y table to which the PCB is attached. 
     The connector is usually placed manually into the corresponding holes in the PCB, after which, by means of the insertion die of the press, the elastic attachment zones of the contact pins of the connector are pressed into the holes in the PCB. 
     If the holes in the PCB do not precisely coincide with the openings or grooves in the anvil, the contact pins of the connector will be pressed together or crushed. 
     This is unacceptable, since is causes irreparable damage to both the contact pins and the connector. 
     The same problem may arise in the event of incorrect alignment or positioning of the upwardly projecting contact pins of a connector with respect to the insertion die of the press. 
     In the absence of a correct alignment means, it is usual to employ the insertion die as an intermediate adjustment piece, the die being positioned manually in the connector before the connector is actually inserted into the PCB. 
     Then, the ram or a planar die can be used to exert pressure on the top side of the insertion die before the connector is inserted into the PCB. 
     It is clear that such a procedure, in which the operator, before each insertion operation, has to arrange the intermediate piece or insertion die on the connector and remove it, wastes considerable time. 
     The object of the present invention is to resolve the problems indicated above in a simple and efficient manner, while also eliminating much time-consuming work. 
     To this end, the method and the device have the characteristic features explained in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in more detail with reference to the following description and drawings, which illustrate an embodiment of a device according to the invention. 
     FIG. 1 shows a diagrammatic side view of a press which is provided with a device according to the invention; 
     FIG. 2 shows a view of a detail of FIG. 1; 
     FIG. 3 shows a plan view of a device according to the invention; 
     FIGS. 4 and 5 show similar views to that shown in FIG. 3, but with the PCB respectively displaced in the direction of the Y-axis and in the direction of the X-axis. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As illustrated in FIG. 1, the press comprises a base structure or frame  50  which is provided with a ram  9  and a fixed table  52 . Support bearings  12 , in which guide shafts  11  are able to move in the direction of the Y-axis, are mounted on the fixed table  52 . 
     Two adjacent guide shafts  11  are fixedly connected to two cross-bars  10  which extend in the direction of the X-axis. The front cross-bar  10  forms the fixed section of the X-carriage  40  and moves the latter with it in the Y-direction in the event of displacement of the guide shafts  11  through the support bearings  12 . 
     The carriage  40  can move in the direction of the X-axis on the cross-bar  10 , inter-alia, by means of the handles  13  which allow manual actuation. 
     A similar carriage  54  is arranged on the rear cross-bar  10 , and the PCB  2  is attached between the rear carriage  54  and the front carriage  40 , it being possible to move this PCB in the direction of the X-axis by means of the carriage  40  and in the direction of the Y-axis by means of the guide shafts  11 . 
     As shown more clearly in FIG. 2, the PCB  2  is, at various locations, provided with series of holes  5  which correspond to the selected insertion zone into which the attachment pins  7  (of the press-fit type) of a connector  1  have to be inserted. 
     For this purpose, the ram  9  of the press is provided with an insertion die  4 , and the fixed table  52  is provided with an anvil  3 . 
     The central point of this insertion die  4  and of the anvil  3  both lie in the same vertical insertion centre line “c”. 
     Since the contact pins  7  of the connector  1  project out of the bottom of the PCB  2  during insertion, the anvil  3  is provided at regular intervals with grooves  6 , in order to create space for the projecting sections of the contact pins  7 . 
     If the connector  1  also contains contact pins  7  which project on the top side, the insertion die  4  is likewise provided with grooves  8  at regular intervals. 
     Consequently, it is clear that the projecting sections of the contact pins  7 , together with the connector housing  1 , have to be accurately aligned, on the one hand with respect to the grooves  6  in the fixed anvil  3 , and on the other hand with respect to the grooves  8  in the insertion die  4 , and this alignment must be correct both in the direction of the X-axis and in the direction of the Y-axis. 
     An exemplary embodiment of the invention is illustrated in FIG.  3 . 
     As already described with reference to FIG. 1, the guide shafts  11  are supported and guided by the support bearings  12 , which are fixedly connected to the frame  50  of the press. 
     On their front side, the guide shafts  11  are connected to a front cross-bar  10 . A carriage  40  can be moved in the direction of the X-axis on this cross-bar  10  by means of the handles  13 . 
     The PCB  2  is supported and guided by means of the front cross-bar  10  and the rear cross-bar  54  and is positioned in the X-direction by means of a fixed (reference point) stop  14  and a moveable stop  15 , which are attached to the carriage  40  and which clamp the PCB  2  in place. 
     The PCB  2 , together with the connector  1  which is to be inserted, can consequently be moved in a horizontal plane, in the direction of the X-axis, from left to right by means of the carriage  40 , and in the direction of the Y-axis by pulling forwards or pushing backwards the assembly comprising carriage  40 , cross-bars  10 - 54  and guide shafts  11  with respect to the fixed support bearings  12  of the frame  50 . 
     One can imagine that such manual positioning of the PCB  2  with connector  1  with respect to the anvil  3  and the insertion die  4  is not a simple operation and cannot be carried out with sufficient accuracy. 
     In order to remedy this problem, the front cross-bar  10  is provided with a linear encoder  17  in order to be able to detect the exact position of the PCB  2  and the insertion zone of the connector  1  in the direction of the X-axis. 
     An identical linear encoder  18  is arranged along one of the guide shafts  11 , in order to be able to detect the exact position of the PCB  2  and the insertion zone of the connector  1  in the direction of the Y-axis. 
     The encoder  17  of the X-axis is electrically connected to the input of an X-control unit  16   a,  which sends a signal to a screen  19  in order to numerically display the position of the X-carriage  40 . 
     The output of the X-control unit  16   a  is connected to a correction motor  27 , which is connected to a guide base  35  and a threaded spindle  26 , on which a correction carriage  25  can move in the direction of the X-axis. The motor  27  and the base  35  are fixed to the X-carriage  40 . 
     The correction carriage  25  is provided with a brake system  24 , which can be moved in the X-direction by the carriage. If the brake is activated, the X-carriage  40  is moved along by the guide base  35  of the correction carriage  25 . 
     According to the invention, the brake system  24  is automatically activated from the moment at which the PCB  2  which is connected to the carriage  40  is displaced manually until the time at which the X-coordinate whose data have been stored in advance in the X-control unit  16   a  comes to lie within a limited distance from the centre line c of the insertion die  4  and the anvil  3 . 
     To carry out a correction in the positioning in the direction of the Y-axis, the encoder  18  is electrically connected to the input of a Y-control unit  16   b,  which sends a signal to the screen  19  in order to display the position of the guide shafts  11  in the direction of the Y-axis, for example numerically. 
     The output of the Y-control unit  16   b  is connected to a correction motor  23 , which is connected to a guide base  31  and a threaded spindle  22  on which a correction carriage  21  can move in the direction of the Y-axis. The correction motor  23  and the guide base  31  are fixed on the frame  50  of the press. 
     The correction carriage  21  is provided with a brake system  20 , which can be moved in the Y-direction by the carriage. If the brake is activated, the guide shaft  11  is moved along by the correction carriage  21 . 
     In this case, the brake system  20  is likewise activated from the moment at which the PCB  2  is moved manually to the time when the Y-coordinate whose data has been stored in advance in the Y-control unit comes to lie within a tracking zone, the area of which extends over a limited distance with respect to the centre line c of the impression die  4  and the anvil  3  of the press. 
     To align an insertion zone of the connector  1  in the PCB  2  with respect to the centre line c of the anvil  3  and the insertion die  4 , it is assumed that the operator has to define a reference position in the X-direction and in the Y-direction. All the coordinates of the insertion zones of the PCB  2  are defined in relation to this reference position. 
     By means of the encoder  17  on the X-axis, the X-control unit  16   a  can be adjusted or adapted to the actual position of the carriage  40  on the X-axis. 
     By means of the encoder  18  on the Y-axis, the Y-control unit  16   b  can be adjusted or adapted to the actual position of the guide shafts  11  and the carriage  40  on the Y-axis. 
     Since the PCB  2  is fixedly connected to the carriage  40 , any position of the PCB  2  will be displayed on the screen  19  using the X and Y coordinates. 
     A programmable function can be used to set the control units  16   a  and  16   b  using a series of X-Y coordinates. According to any X-Y coordinate, the holes  5  in the insertion zones of the PCB  2  must correspond to the grooves  6  in the anvil  3 , and consequently also to the grooves  8  in the insertion die  4 , since anvil  3  and die  4  are fixedly connected to the frame  50  of the press and lie in the same vertical centre line c. 
     While the positioning program is running, the control units  16   a  and  16   b,  with the aid of the encoders  17  and  18 , will establish the direction in which the carriage  40  will have to be moved. 
     This may, for example, be achieved by means of arrows which, on the screen  19 , indicate the direction in which the carriage  40 , together with the PCB  2  and the connector  1 , has to be moved. 
     If the carriage  40  is moved in such a way that it comes to lie at a limited, predetermined distance close to the programmed Y-coordinate or centre line c, the Y-control unit  16   b  will activate the break system  20 . 
     On the other hand, if the carriage  40  comes to lie at a defined distance close to the programmed X-coordinate or centre line C, the X-control unit  16   a  will activate the brake system  24 . 
     At that moment, the carriage  40  is blocked in both directions, and the screen  19  shows that the press can be operated. 
     By means of the encoders  17  and  18 , the control unit, comprising an X-control unit  16   a  and a Y-control unit  16   b,  can detect the actual position of the centre point p of the insertion zone z of the PCB  2  together with the connector  1 . 
     If the actual position in the direction of the X-axis differs from the X-coordinate in the program, the X-control unit  16   a  will start the motor  27 . This motor  27  will produce a rotational movement of the threaded spindle  26 , with the result that the correction carriage  25  will be moved to the left or to the right. 
     Since the brake system  24  is fixedly connected to the correction carriage  25 , and as the brake system  24  is clamped to the cross-bar  10  of the X-axis, the X-carriage  40  will move to the left or to the right through the rotation of the motor  27 . 
     If the X-control unit  16   a  rotates the motor  27  in a direction which is such that the actual X-position coincides with the programmed X-coordinate of the centre line c, the holes  5  in the PCB  2  will coincide in the X-direction with the grooves  6  in the anvil  3 . 
     If the actual position in the direction of the Y-axis differs from the programmed Y-coordinate, the Y-control unit  16   b  will start the motor  23 . This motor  23  will rotate the threaded spindle  22 , with the result that the correction carriage  21  will be moved forwards or backwards. 
     Since the brake system  20  is fixedly connected to the correction carriage  21 , and as the brake system  20  is likewise clamped to the guide shaft  11  in the direction of the Y-axis, the X-carriage  40  will be moved forwards or backwards through the rotation of the motor  23 . 
     The Y-control unit  16   b  will rotate the motor  23  in such a direction until the actual Y-position coincides with the programmed Y-coordinate of the centre line c, and then the holes  5  in the PCB  2  in the Y-direction will coincide with the grooves  6  in the anvil  3 . 
     Before the press is actuated, the X-control unit  16   a  and the Y-control unit  16   b,  by means of the encoders  17  and  18 , will check the actual position of the PCB  2 . 
     By means of the device according to the invention, the PCB  2  can rapidly be moved from one insertion position to the other. As soon as the PCB  2  is approximately within the limited tracking zone of correction carriages  21  and  25 , the brake systems  20  and  24  are activated. 
     The control units  16   a,    16   b  and the motors  23 ,  27  then automatically assume responsibility for the further fine adjustment of the position of the PCB  2 . 
     A fine adjustment in the direction of the X- and Y-axes is also necessary for accurate positioning of the insertion die  4  with respect to the connector housing  1 , if the insertion die, which is generally of rectangular shape, has to penetrate into the connector housing, which is of corresponding design, as illustrated in FIG.  2 . 
     Key to reference numerals 
       1 : connector (body) 
       2 : printed-circuit board 
       3 : anvil 
       4 : insertion die 
       5 : hole in the printed-circuit board 
       6 : groove in the anvil 
       7 : contact pin (press-fit) 
       8 : groove in the insertion die 
       9 : ram 
       10 : front cross-bar of X-carriage 
       11 : guide shaft 
       12 : support bearing 
       13 : handle 
       14  fixed (reference point) stop 
       15 : moveable stop 
       16   a,b:  X- and Y-control units, respectively 
       17 : X-axis encoder 
       18 : Y-axis encoder 
       19 : screen 
       20 : Y-axis brake system 
       21 : Y-axis correction carriage 
       22 : Y-axis threaded spindle 
       23 : Y-axis correction motor 
       24 : X-axis brake system 
       25 : X-axis correction carriage 
       26 : X-axis threaded spindle 
       27 : X-axis correction motor 
       31 : Y-axis guide base 
       35 : X-axis guide base 
       40 : Y-axis carriage 
       50 : frame 
       52 : fixed table 
       54 : rear cross-bar of X-carriage

Technology Category: y