Patent Publication Number: US-2001000366-A1

Title: Electronic component mounting apparatus for exchanging support blocks which support circuit boards

Description:
SPECIFICATION  
     1. This is a divisional application of Ser. No. 08/761,077, filed Dec. 17, 1996.  
    
    
     
       BACKGROUND OF THE INVENTION  
       2. The present invention relates to an electronic component mounting apparatus and method for mounting electronic components on boards to thereby produce electronic circuit boards, and more particularly, to an electronic component mounting apparatus equipped with an exchange device for exchanging support blocks which support the boards, and an electronic component mounting method of exchanging support blocks supporting the boards.  
       3. A conventional system will be described with reference to FIGS. 5A and 5B.  
       4.FIGS. 5A and 5B are enlarged sectional views of an essential portion of a support block in a conventional electronic component mounting apparatus. In FIGS. 5A and 5B, a board  14  to which electronic components, etc. are mounted is positioned at a predetermined position over a support block  16  by a transfer belt device  15 . The support block  16  is then raised and the board  14  is held on support pins  17  provided in the support block  16 . After this, electronic components, etc. are mounted to the board  14 .  
       5. Setting positions of the support pins in the support block are selected depending on the desired characteristics of rear faces of boards to be produced. In switching the kind of boards in the conventional mounting apparatus, therefore, the support blocks should be changed in accordance with the desired characteristics of the rear faces of the boards, which requires additional processing time. In the case where the volume of production is relatively low and there are a wide variety of kinds of products, namely, boards to be made, this exchange of support blocks inconveniently deteriorates the productivity.  
       SUMMARY OF THE INVENTION  
       6. Accordingly, an object of the present invention is to provide an electronic component mounting apparatus and method which shorten a time required for switching the kinds of boards to be produced and enhance the working efficiency of the facilities, thereby improving the productivity.  
       7. In accomplishing these and other objects, according to a first aspect of the present invention, there is provided an electronic component mounting apparatus comprising:  
       8. a plurality of support blocks one of which supports a board when mounting an electronic component, wherein a support block is automatically selected from among the plurality of support blocks and exchanged in accordance with the switching of the kind of boards to be supported by the support block.  
       9. According to a second aspect of the present invention, there is provided an electronic component mounting apparatus according to the first aspect of the present invention, further comprising: a storing device for storing the plurality of support blocks; and a support block moving device for selecting one of the support blocks stored in the storing device in accordance with the switching of the kind of boards and moving the selected support block from the storing device to a position where the board is supported by the selected support block.  
       10. According to a third aspect of the present invention, there is provided an electronic component mounting apparatus according to the first aspect of the present invention, further comprising a single support block driving device for upwardly moving the support block to support the board when the electronic component is mounted on the board, downwardly moving the support block to stop supporting the board, and exchanging the support block with another support block.  
       11. According to a fourth aspect of the present invention, there is provided an electronic component mounting apparatus according to the second aspect of the present invention, wherein the support block moving device moves the support block upward to support the board when the electronic component is mounted on the board, and moves the support block downward to stop supporting the board.  
       12. According to a fifth aspect of the present invention, there is provided an electronic component mounting method comprising:  
       13. selecting one of a plurality of support blocks in correspondence with a kind of board to be supported, based on data indicating relationships between kinds of boards and the support blocks corresponding to the kinds of boards; and  
       14. exchanging a present support block with the selected support block.  
       15. According to a sixth aspect of the present invention, there is provided an electronic component mounting method according to the fifth aspect of the present invention, further comprising, before selecting the support block, inputting the data indicating the relationship between the kinds of boards and the support blocks corresponding to the kinds of boards.  
       16. According to seventh and eighth aspects of the present invention, there is provided an electronic component mounting method according to the fifth and sixth aspects of the present invention, further comprising displaying an error when the selected support block is not stored in a support block storing device.  
       17. According to a ninth aspect of the present invention, there is provided an electronic component mounting apparatus according to the first aspect of the present invention, wherein the support blocks are different with respect to the positions of pins provided for supporting the boards.  
       18. According to a tenth aspect of the present invention, there is provided an electronic component mounting apparatus according to the second aspect of the present invention, wherein the support blocks are different with respect to the positions of pins provided for supporting the boards.  
       19. According to an eleventh aspect of the present invention, there is provided an electronic component mounting method according to the fifth aspect of the present invention, wherein the support blocks are different with respect to the positions of pins provided for supporting the boards.  
       20. According to a twelfth aspect of the present invention, there is provided an electronic component mounting method according to the sixth aspect of the present invention, wherein the support blocks are different with respect to the positions of pins provided for supporting the boards.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     21. These and other aspects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, in which:  
     22.FIG. 1 is a schematic diagram of an electronic component mounting apparatus for carrying out an electronic component mounting method, according to one embodiment of the present invention;  
     23.FIG. 2 is an enlarged sectional view of a portion of the apparatus for explaining the embodiment of the present invention;  
     24.FIG. 3 is a flow chart showing a method;  
     25.FIGS. 4A and 4B are views showing different clamp mechanisms between a cylinder and a board of the apparatus; and  
     26.FIGS. 5A and 5B are enlarged sectional views of an essential portion of a support block of an electronic component mounting apparatus in the prior art.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     27. Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.  
     28. Hereinbelow, one embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 schematically shows an electronic component mounting apparatus according to one embodiment of the present invention. FIG. 2 is an enlarged sectional view of a portion explanatory of a support block exchange device of the apparatus in the present invention. First, a mounting process for electronic components will be discussed with reference to FIG. 1. In FIG. 1, a head part  1  having a suction nozzle for holding an electronic component is positioned by an XY robot  2  movable in X and Y directions perpendicularly to each other. The head part  1  draws a predetermined electronic component from a component feed part  3  and holds the component by suction, and the component is then positioned over a component recognition camera  4 . A posture of the component held by suction is detected on the basis of an image obtained by the recognition camera  4 . A shifting amount of the head part  1  when holding the electronic component is corrected based on the data obtained with respect to the posture. The head part  1  is consequently positioned at a predetermined position on a board  5 , so that the electronic component is accurately mounted to the predetermined position on the board  5 .  
     29. Now, take-in and take-out processes for the board  5  according to the embodiment will be explained with reference to FIG. 2.  
     30.FIG. 2 shows: a transfer belt device  6  for transferring the board  5 ; support pins  7  disposed on each of a plurality of plate-shaped support blocks  8 ; a motor  9  for driving up and down a support block holding table  10  holding the support block  8 ; a rack  11 , serving as a support block storing device, provided at one side of the holding table  10  for storing a plurality of support blocks  8  with support pins  7  arranged in different manners; a clamp part  12  for exchanging the support blocks  8 ; and a cylinder  13  for driving the clamp part  12 .  
     31. The motor  9  rotates a driving pulley  9   a  which is connected to a pair of pulleys  9   d  by a belt  9   b  so as to rotate the pulleys  9   d  together with the rotation of the driving pulley  9   a . A pair of driving shafts  9   c  has the pulleys  9   d  fixed to the lower ends thereof and nuts  10   a  fixed to the holding table  10  and engaged with the driving shafts  9   c  so that the driving shafts  9   c  rotate with respect to the engaged nuts  10   a  to move the holding table  10  upward and downward. Thus, when the motor  9  rotates the driving pulley  9   a  in both directions, the pulleys  9   d  are rotated by the belt  9   b  so as to rotate the driving shafts  9   c  in both directions to move the holding table  10  upward and downward. The holding table  10  has a pair of guide rails  10   c  for guiding the support block  8  on the holding table  10  in a direction perpendicular to the transport direction of the board  5  as transported by the transfer belt device  6 . Thus, a support block moving device is constituted by the motor  9 , the driving pulley  9   a , the belt  9   b , the driving shafts  9   c , the pulleys  9   d , the holding table  10 , the clamp portion  12 , and the cylinder  13 .  
     32. The cylinder  13  has a piston rod  13   a  with the clamp part  12  at its end. The clamp part  12  clamps the support block  8  on the holding table  10  so as to position the support block  8  thereon without any movement. One example of the clamp part  12  is shown FIG. 4A. This clamp part includes a rotatable plate  13   b  fixed to the end of the piston rod  13   a  and a pair of positioning pins  8   a  fixed on the support block  8 . When the holding table  10  with no support block  8  thereon is caused to face the support block  8  in one slot of the rack  11  and the piston rod  13   a  of the cylinder  13  is rotated clockwise from a removal position shown by dotted lines to an engaging position shown by solid lines, the positioning pins  8   a  of the support block  8  are inserted into and engaged with holes  13   c  of the rotatable plate  13   b , and the piston rod  13   a  is forward moved so as to move forward the support block  8  from the slot of the rack  11  to a predetermined position of the holding table  10  while guided by the rails  10   c . Conversely, when the holding table  10  with the support table  8  thereon is caused to face a vacant slot of the rack  11 , the piston rod  13   a  is moved backward and then the support block  8  is moved from the predetermined position of the holding table  10  while guided by the rails  10   c  to the vacant slot of the rack. Then, the support block  8  is stored in the slot, the piston rod  13   a  of the cylinder  13  is rotated counterclockwise from the engaging position to the removal position and then, the positioning pins  8   a  of the support block  8  are removed and disengaged from the holes  13   c  of the rotatable plate  13   b.    
     33. Another example of the clamp part  12  is shown in FIG. 4B. In FIG. 4B, the cylinder  13  has a U-shaped piston rod  13   e  and a T-shaped clamp portion  13   f  at its end. The support block  8  has a T-shaped recess  8   b  into which the T-shaped clamp portion  13   f  can be engaged. Thus, when the support block  8  is moved from the slot of the rack  11  to the holding table  10 , the U-shaped piston rod  13   e  is rotated to engage the T-shaped clamp portion  13   f  into the T-shaped recess  8   b  of the support block  8 .  
     34. The apparatus further comprises a controller  100  for controlling the exchange of the support blocks  8 , an input device  101  such as a key board for inputting instructions into the controller  100  therethrough, a display  104  for displaying an error when the selected support block  8  is not stored in the rack  11 , and sensors  102   a ,  102   b ,  102   c , and  102   d , located at slots of the rack  11 , for detecting presence of the support block  8  at each slot in the rack  11  to input such information into the controller  100 . The controller  100  is connected to the input device  101 , the display  104 , the sensors  102   a - 102   d , the motor  9 , the cylinder  13 , and a board detection sensor  90  so that the controller  100  controls operations of the cylinder  13  and the motor  9  based on the input information from the input device  101 , the sensors  102   a - 102   d , and the board detection sensor  90 . Reference numeral  110  denotes a pair of stoppers for positioning the support block  8  at the predetermined position on the holding table  10  by contacting the side surface of the support block  8  with the stoppers  110 .  
     35. Instead of the provision of the sensors  102   a - 102   d , there can be provided a sensor  103  located at the side surface of the support block holding table  10  which faces the slots of the rack  11  so as to detect presence of the support block  8  at each slot of the rack  11 . In this case, when the support block holding table  10  moves downward and upward, the sensor  103  detects the presence of the support block  8  at each slot of the rack  11  to input such information into the controller  100 .  
     36. First, a board  5  where the electronic component is to be mounted is transferred by the transfer belt device  6  to a position above the support block  8  having the plurality of support pins  7 . At this time, when it is detected by the board detection sensor  90  or the like that the board  5  has reached a predetermined position above the support block  8 , the holding table  10  is raised to a predetermined position by the motor  9  based on the control operation of the controller  100  to hold the board  5  on the support pins  7  of the support block  8 . Then, the electronic components are mounted on the board  5  held by the support block  8 , and, upon completion of the mounting, based on the control operation of the controller  100 , the holding table  10  is lowered to a predetermined position by the motor  9 . The board  5  having the mounted electronic components is taken out by the transfer belt device  6 .  
     37. An operation for exchanging support blocks  8  corresponding to the switching of the kind of boards  5  based on the control operation of the controller  100 , will be discussed below. When the kind of boards  5  is changed, the support block  8  should match the switched board  5 . That is, the support pins  7  on the support block  8  should be arranged to conform to the switched board  5 . The storing rack  11  stores the support blocks  8  corresponding to a plurality of kinds of boards  5 . In order to exchange the support blocks  8  (i.e. in order to exchange a selected support block for a support block which had been in use), the holding table  10  is positioned by the motor  9  relative to a vacant slot in the storing rack  11 , and the support block  8  currently used is clamped by the clamp part  12  arranged over the holding table  10  and moved to the vacant slot of the rack  11  by the cylinder  13  as described above. After the support block  8  is accommodated in the vacant slot, the clamp part  12  is released and the holding table  10  is positioned by the motor  9  to a position in the rack  11  of the support block  8  to be used next. The support block  8  to be used next is clamped by the clamp part  12  and set at the predetermined position on the holding table  10  by the cylinder  13 . The holding table  10 , after exchanging the support blocks  8 , is raised again by the motor  9  when the exchange operation is finished.  
     38. The support blocks  8  can be automatically exchanged if the support blocks  8  corresponding to the kinds of boards  5  are preliminarily designated and input in mounting programs stored in the controller  100  of the apparatus. The mounting program corresponding to the kind of boards  5  is selected, to thereby automatically select and exchange the corresponding support block  8 . The exchange operation may also be carried out simply through the input device  101  such as a key input, without inputting of a mounting program.  
     39. That is, in such a case, the electronic component mounting method according to the embodiment is executed in accordance with the flow chart shown in FIG. 3. First, at step S 1 , data indicating the relationship between the kinds of boards  5  and the support blocks  8  corresponding to the kinds of boards  5  is input into the controller  100  through the input device  100 . At step S 2 , by the controller  100 , one of support blocks  8  in correspondence with a kind of board  5  to be supported is selected based on the input data indicating the relationship. At step S 3 , it is decided by the controller  100  whether or not the selected support block  8  is stored in the rack  11 . If the selected support block  8  is not stored in the rack  11 , an error is displayed on the display  104  at step S 5 . When the selected support block  8  is stored in the rack  11 , the moving amount of the holding table  10  is determined in accordance with the number of the slot where the selected support block  8  is stored in the rack  11  and the number of a vacant slot where the support block  8  placed on the holding table  10  will be stored. At step S 4 , the holding table  10  is driven by the motor  9  based on the determined moving amount and the present support block  8  on the holding table  10  is caused to face the vacant slot of the rack  11  to move the support block  11  into the vacant slot. Then, the holding table  10  is moved to face the selected support block  8  stored in the slot of the rack  11  and the selected support block  8  is taken out from the slot.  
     40. As is described hereinabove, in the electronic component mounting apparatus according to the embodiment of the present invention, the plurality of support blocks for supporting the boards when mounting the electronic components, etc. thereon are provided. The support block corresponding to the kind of boards is automatically selected among the plurality of support blocks when the kind of boards is changed. Accordingly, the switching time for switching the kind of boards is reduced and the working efficiency of the facilities is enhanced, thus improving the productivity for mounting the electronic components. The plurality of support blocks provided in the electronic component mounting apparatus are stored in the storing device set at one side of the support block moving device. When the support blocks are to be exchanged, the current support block is stored in a vacant slot of the storing device, and the support block to be used next is fed from the storing device. The up-and-down movement of the support block when the electronic components are mounted on the board is carried out by the same driving device as when the support block is moved up and down to be exchanged. The driving arrangement can thus be simplified.  
     41. The electronic component mounting apparatus can include a process for inputting data of the support blocks corresponding to the kinds of boards to be produced, a process for selecting the corresponding support block based on the input data, and a process for exchanging the present support block with the selected support block, whereby the required support block can be automatically exchanged on the basis of the selection of a mounting program corresponding to the kind of boards.  
     42. Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.