Abstract:
In a docking apparatus for coupling a first apparatus consisting of a handler or prober and a second apparatus consisting of a testing head for electronic components, at least one locking unit is provided having an axial insertion opening for inserting a locking pin. In the area of the insertion opening, a plurality of balls are arranged, between which the locking pin is insertable. Furthermore, a ball clamping sleeve is provided, which by means of an axial displacement causes a radial movement of the balls and therefore fixes the locking pin.

Description:
CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED APPLICATIONS 
   To the full extent permitted by law, the present application claims priority to and the benefit of German application, number 102 16 003.1, entitled “Dockingvorrichtung”, filed Apr. 11, 2002, wherein the application is incorporated herein by reference. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention refers to a docking apparatus for coupling a first apparatus consisting of a handler or prober with a second apparatus consisting of testing head for electronic components, according to the preamble of claim  1 . 
   BACKGROUND OF THE INVENTION 
   For testing electronic components, such as integrated circuits (IC) it is known to use a testing apparatus having a testing head which must be connected to a handling device for the electronic component, such as a handler or prober. In order to facilitate docking of the testing head having a weight of up to 1000 kg to the handling device in a manner as simple, easy and precise as possible, special docking devices, i.e. coupling devices, have been developed which are attached on the one hand on the handling device and on the other hand on the testing head. It is, however, a drawback of such prior art docking devices that they do not always enable docking of the testing head in the desired simple, easy and precise manner and moreover are costly and have a complex structure. 
   BRIEF DESCRIPTION OF THE INVENTION 
   It is thus an object of the present invention to provide a docking apparatus of the above kind having a simple and inexpensive structure and enabling simple, easy and precise coupling of the handling device to the testing head. 
   The object is solved according to the present invention by the features of claim  1 . Advantageous embodiments of the present invention at least one locking unit are described in the dependent claims. 
   In the docking apparatus of the present invention at least one locking unit is provided attached on a docking plate, comprising:
         an axial insertion opening for inserting the locking pin.   a plurality of balls arranged in the area of the insertion opening, between which the locking pin is insertable.   a ball clamping sleeve enabling, in a first axial position, a radial position of the balls outside of the insertion area of the locking pin, in which the locking pin is insertable between the balls, and locking, in a second axial position, the balls in a locked position, in which the balls protrude into a circumferential groove of the inserted locking pin.       

   The docking apparatus according to the present invention enables a very simple, smooth and precise docking of the testing head at the handling device and can be manufactured relatively easily and cheaply. Moreover, the docking apparatus may be formed very easily in such a way that the locking unit(s) may be very easily attached at various places of the docking plate, so that when changing the type of testing head or handling device often only the locking units need to be attached at different positions of the docking plate in order to fit to a different testing head or a different handling device. The docking apparatus is therefore also more easily adaptable to various device types. 
   It is particularly advantageous if the insertion opening for the locking pin comprises a centering section formed as a centering bore of the locking pin. The docking apparatus therefore not only serves as a contraction apparatus but also as a centering means allowing the testing head to be centered precisely with respect to the handling device. 
   According to an advantageous embodiment, the locking unit comprises a threaded sleeve having an internal thread and being rotatable by the actuating means. Herein, the ball clamping sleeve is non-rotatable, however it is displaceable in an axial direction and has an external thread running in mesh with the internal thread of the threaded sleeve, so that rotating the threaded sleeve is coupled with an axial movement of the ball clamping sleeve. Thus, the threaded sleeve acts as some kind of axially fixed spindle nut, while the non-rotatable ball clamping sleeve is comparable to a spindle that is axially displaced by rotating the threaded sleeve. 
   According to an advantageous embodiment, the ball clamping sleeve comprises a ball clamping section radially protruding to the inside and having a dome-shaped ball guiding surface. When the balls move along the dome-shaped ball clamping section, they are forced to carry out a movement in the radial direction as well as the axial movement, enabling the balls to be brought in and out of locking engagement with the locking pin. The movement of the balls along the dome-shaped ball clamping section can for example be effected by moving the ball clamping sleeve in an axial direction against a limit stop protruding into the receiving space of the balls, the limit stop, from a certain axial position onwards, preventing the balls from being moved further in an axial direction, whereupon, with a further axial movement of the ball clamping sleeve, the balls are moved by the limit stop along the dome-shaped ball clamping section and therefore radially to the inside. Instead of a dome-shaped form of the ball clamping section, other shapes are also possible, such as tapering angular surfaces. 
   According to a particularly advantageous embodiment, the actuating means for locking and unlocking the locking pin is comprised of a Bowden wire means coupled to the threaded sleeve in such a way that the latter may be caused to rotate by the Bowden wire means. Such Bowden wire means enable the individual locking units to be attached at various positions on the docking plate, without the actuating means having to be adapted in any special way. 
   It is also advantageous for the threaded sleeve to be mounted to be rotatable within a housing portion attached on a mounting plate. Thus, all parts of a locking unit are on a mounting plate, so that only the attachment plate need be screwed off and attached at the new desired position on the docking plate if a displacement of a locking unit is required. This enables in a particularly efficient way a simple and quick relocation of the locking units. 
   According to an advantageous embodiment, the balls are arranged in a ball cage moveable in a radial direction and fixed in an axial direction with respect to the ball cage. To do this, the ball cage suitably has radial guides for the balls, precisely guiding the balls in an axial direction and only allowing a movement in the radial direction. 
   According to an advantageous embodiment, the ball cage is axially displaceable with respect to the docking plate and has a limit stop surface for the locking pin. The limit stop surface is arranged in such a way that the circumferential groove of the locking pin abutting on the limit stop surface faces the balls. In this case, the ball cage is moved in an axial direction together with the balls by the locking pin itself until the ball cage has reached its axial end position. The movement of the ball cage is suitably carried out against the biasing force of a spring. This enables very soft docking, since the locking pin already inserted in the insertion guide does not abruptly impact on a fixed axial stop but the axial stop may still be displaced a bit further in the axial direction against the increasing force of a spring. In this way, also intermediate axial positions are possible, in which the locking pin has not yet been locked by the balls, however does experience a certain retention force, so that manual alignment of the, testing head is still possible without the risk of the locking pin being withdrawn from the insertion opening. 
   According to an advantageous embodiment, three locking units are provided on the docking plate, into each of which a locking pin is insertably mounted on the opposite device. A different number of locking units is easily possible, such as two, four or five locking units. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail in the following with reference to the accompanying drawings, in which: 
       FIG. 1  is a schematic view of a handling device, a testing head and a docking apparatus for coupling the two devices; 
       FIG. 2  is schematic view of a locking unit by itself; 
       FIG. 3  is a sectional view along line B—B of  FIG. 4  of a locking unit, where a locking pin is shown at the beginning of the insertion process; 
       FIG. 4  is a sectional view taken along the line A—A of  FIG. 3 ; 
       FIGS. 5   a - 5   c  show the locking unit together with the locking pin of  FIG. 3 , wherein the different insertion positions of the locking pin are shown; 
       FIGS. 6   a ,  6   b  are schematic views to illustrate various possibilities for attaching the locking units on a docking plate; 
       FIG. 7  is a sectional view of a ball clamping sleeve by itself; and 
       FIG. 8  is a sectional view of a ball cage. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   With reference to  FIG. 1 , a handling device  1  as well as a testing head  2  are shown. For docking the testing head  2  to the handling device  1 , a docking plate  3  is used attachable either directly on the handling device  1  or on an intermediary frame (not shown), an overall number of three locking units  4  being attached on the docking plate  3 . The locking units  4  are disposed in three corner areas of the docking plate  3  and mechanically coupled to a handling portion  6  via a Bowden wire means  5 , the handling portion  6  being in the fourth corner of the docking plate  3 . 
   Three locking pins  7  are attached on the testing head  2  and protrude beyond the testing head  2  and, as will be described in the following in more detail, are capable of being brought into engagement with the locking units  4 . 
   The docking of the testing head  2  on the handling device  1  is done in such a way that first the testing head  2  is moved toward the handling device  1  or the docking plate  3  until the locking pins  7  are inserted in central insertion openings  8 , referenced in  FIGS. 1 and 2 , of the locking units  4 , allowing the testing head  2  to be centered. Next, the locking units  4  are actuated by turning the handling portion  6  in such a way that the locking pins  7 , and thus also the testing head  2 , are drawn further to the docking plate  3  up to the end position, and is locked in this position. 
   With reference to  FIGS. 3 and 4 , in the following, the structure and operation of the locking units  4  is more fully explained. The three locking units shown in  FIG. 1  are formed to be identical. As can be seen in particular from  FIG. 3 , each locking unit  4  has an attachment plate  9 , which may be screwed to the docking plate  3  by means of screws (not particularly shown). 
   An annular or sleeve-shaped housing portion  10  having a circular cross section is attached on the attachment plate  9 . The top of the housing portion  10  is covered by a circular cover  11  having a central centering bore  12 . The diameter of this centering bore  12  is precisely matched to the outer diameter of the cylindrical locking pin  7 , so that a tight fit is provided. Alternatively it is also possible to provide the centering bore  12  in a separate centering bush (not shown) inserted in the cover  11 . The centering bore  12  and an adjacent receiving space  26  for a ball cage  24  to be described in more detail below, together form the insertion opening  8  for the centering pin  7 . 
   Within the housing portion  10 , a threaded sleeve  13  in the form of a hollow cylinder is rotatable, the threaded sleeve  13  having its outer circumferential surface lying against the inner circumferential surface of the housing portion  10 . The threaded sleeve  13  has an internal thread  14  extending over its entire axial length. 
   Within the threaded sleeve  13 , a ball clamping sleeve  15  is arranged to be axially displaceable, having an external thread  16  on its outer circumference. This external thread  16  is in mesh with the internal thread  14  of the threaded sleeve  13 . Further, the ball clamping sleeve  15  is fixed in a non-rotatable manner within the housing portion  10  by two axial guiding pins  17  axially extending through the ball clamping sleeve  15 . The ball clamping sleeve  15  therefore may be displaced in an axial direction in the manner of a spindle, when the threaded sleeve  13  is rotated. 
   The structure of the threaded sleeve  13  is shown in more detail in FIG.  7 . The threaded sleeve has a central, axial passage  18  having various diameters. The top end section  19  of the passage  18  thus has a smaller diameter than the main section  21  due to a web  20  protruding radially to the inside. The main section  21  and the end section  19  are linked by a dome-shaped intermediary section  22 , serving as a ball guiding surface. The web  20  is a ball clamping section, as will be explained in more detail below. Moreover, two through bores  23  are provided radially outside of the passage  18 , serving to receive the guiding pins  17 . 
   As can be seen from  FIGS. 3 and 4 , the locking unit  4  has a ball cage  24  serving to guide and hold balls  25 . The ball cage  24  in turn is centrally disposed and has a smaller outer diameter than the clear diameter of the end section  19  of the ball clamping sleeve  15 . The ball cage  24  is therefore displaceable in an axial direction with respect to the ball clamping sleeve  15 , the ball clamping sleeve  15  surrounding the ball cage  24 . 
   The ball cage  24  is shown by itself in FIG.  8 . The ball cage  24  is essentially cup-shaped and has an annular circumferential side wall  28  as well as a flat bottom  27 . In the upper area of the side wall  28 , a total number of eight radially extending ball entry openings  29  are provided, penetrating the side wall  28  and regularly spaced about its circumference. 
   The diameter of the ball entry openings  29 , at the radial outer end, is a bit greater than that of the balls  25 , so that the balls  25  may move radially from the outside to the inside into the ball entry openings  29 . At the radial inner end, the diameter of the ball entry openings  29 , however, is a bit smaller than that of the balls  25 , which prevents the balls  25  from completely falling into the cavity of the ball cage  24 . The cavity of the ball cage  24  is slightly conical toward the bottom and is therefore adapted to the form of the free end area of the locking pin  7 . 
   The bottom end of the cavity forms a limit stop surface  30  for the end face of the locking pin  7 . Further, the outer diameter of the bottom section of the ball cage  24  is smaller than that of the top section, so that a circumferential shoulder  31  is formed serving as an abutment surface of the spring  32  (FIG.  3 ). 
   As can be further seen from  FIGS. 3 and 5   a - 5   c , a guiding ring  33  is provided between the ball clamping sleeve  15  and the ball cage  24 . This guiding ring  33  extends upwards from the attachment plate  9  only over a smaller part of the overall height up to the cover  11  and is for radial guidance of the spring  32  and the ball cage  24 , which may plunge into the guiding ring  33 . 
   The ball cage  24  is biased upwardly, i.e. away from the attachment plate  9 , by the spring  32 , the spring  32  being supported at the bottom by the attachment plate  9  and at the top by the shoulder  31  of the ball cage  24 . The spring  32  extends in a space between the ball cage  24  and the guiding ring  33 . 
   In order for the cage  24  to be able to execute an axial movement, the height of the ball cage  24  is considerably smaller than the distance between the attachment plate  9  and the cover  11 . 
   The threaded sleeve  13  can be rotated by means of a Bowden wire means  5  about the central rotary axis  34 . To do this, the Bowden wire means  5  has two Bowden wire holders  36   a ,  36   b  fixed at opposite ends of the attachment plate  9 , to which ends wire cable sleeves  37   a ,  37   b  may be fixed coming from opposing sides. The wire  38   a  is passed around the threaded sleeve  13  counter-clockwise and is fixed to the end side thereof. The wire  38   b  is passed clockwise around the threaded sleeve  13  and is also fixed to the end side thereof. The wires  38   a ,  38   b  are disposed in outer circumferential grooves  39   a ,  39   b  (FIG.  3 ). Further, the wires  38   a ,  38   b  are connected to a drum (not shown in more detail) within the handling portion  6  (FIG.  1 ), so that upon rotating the drum by means of a hand lever  40 , one wire is wound up and the other wire is unwound. Depending on the direction in which the handling portion  6  is rotated, the threaded sleeve  13  is therefore also rotated to the right or to the left. 
   With reference to the  FIGS. 5   a - 5   c  the docking operation will now be described in more detail. 
   In  FIG. 5   a , the beginning of the entry of the locking pin  7  into the centering bore  12  of the cover  11  is shown. In order to facilitate insertion of the locking pin  7 , the latter has a conical end area  41 . Adjacent to this conical end area  41 , there is a circumferential groove  42 , extending round the entire circumference of the locking pin  7 . Adjacent to the circumferential groove  42 , in turn, there is a cylindrical centering section  43 . In this position, the threaded sleeve  13  is rotated back to such an extent that the ball clamping sleeve  15  is in the uppermost position, i.e. adjacent to the cover  11 . In this position, the balls  25  have sufficient radial play toward the outside, to pass completely outside the cavity  44  of the ball cage  24 . Due to the compressive force of the spring  32 , the ball cage  24  is in its topmost position, where it abuts against the cover  11 . In the position shown in  FIG. 5   a , the conical end area  41  of the locking pin  7  thus only acts together with the centering bore  12  in such a way that a certain pre-centering of the locking pin  7  and therefore the testing head  2  is effected. 
   An intermediate position is shown in  FIG. 5   b , in which the locking pin has been inserted into the locking unit  4  to such an extent that the centering section  43  of the locking pin  7  comes to lie within the centering bore  12  and therefore a centering of the testing head  2  is ensured. Furthermore, in this position, the end face  45  of the locking pin  7  abuts against the bottom limit stop surface  30  of the ball cage  24 , already slightly displacing the ball cage  24  to the bottom against the force of the spring  32 . In this position, the ball entry openings  29  of the ball cage  24  directly face the circumferential groove  42  of the locking pin  7 , so that the balls  25  may be moved to the inside and enter into the circumferential groove  42 . This is done by rotating the threaded sleeve  13  via the Bowden wire means  5 , so that the ball clamping sleeve  15  is moved to the bottom, i.e. away from the cover  11 . If the ball clamping sleeve  15  is moved in an axial direction to the bottom further than the ball cage  24 , and if there is thus a relative movement between these two parts, then the balls  25  are urged toward the inside by the dome-shaped intermediary section  22  of the ball clamping sleeve  15 . In this intermediary position, the locking pin  7  has been slightly axially fixed by the balls  25 , so that it may not easily be withdrawn from the insertion openings  8 . At the same time, however, a certain flexibility is provided in an axial direction, since the locking pin  7  and therefore the testing head  2  may still be manually adjusted in the insertion direction, wherein the ball cage  24  moves independently of the ball clamping sleeve  15  against the force of the spring  32  in the direction of the attachment plate  9 . 
   A complete drawing-in and locking of the locking pin  7  is done by rotating the threaded sleeve  13  by means of the Bowden wire means  5  to such an extent that the ball clamping sleeve  15  is in the position shown in  FIG. 5   c  near the attachment plate  9 . In the axial movement of the ball clamping sleeve  15  from the position shown in  FIG. 5   b  to the one shown in  FIG. 5   c , the balls  25  are carried along in an axial direction and simultaneously urged to the inside into the circumferential groove  42  of the locking pin  7 . Via the balls  25 , therefore, both the ball cage  24  and the locking pin  7  are moved along in an axial direction. In the locking position shown in  FIG. 5   c , the ball cage  24  is also adjacent to the attachment plate  9 . The locking pin  7  and therefore also the testing head  2  are both centered and axially locked. 
   On order to release the locking pin  7  from the locking unit  4 , the threaded sleeve  13  is turned back by means of the Bowden wire means  5  in the opposite direction to the starting position shown in  FIG. 5   a , again creating sufficient radial space for the balls  25 , so that the balls  25  may exit from the circumferential groove  42  and release the locking pin  7 . 
   With reference to  FIGS. 6   a  and  6   b  it may be seen that the locking units  4  may easily be attached at various positions of the docking plate  3  without the Bowden wire means  5  itself having to be changed. In  FIG. 6   a , the locking units  4  and the handling part  6  have been screwed into attachment openings  46  of the docking plate  3 , relatively close to the edge of the docking plate  3 . The Bowden wire is relatively extended. In  FIG. 6   b , however, the locking units  4  and the handling portion  6  are further to the inside, the Bowden wire buckling to the outside.