Abstract:
Disclosed is a component mounting method. Moved in first and second orthogonal directions is a first mounting head section having first nozzles. The first mounting head is rotated such that the first nozzles rotate and successively pickup components from a first component supply table arranged on one side of a board transfer path. These components are then successively mounted onto a board positioned in the board transfer path. Moved in third and fourth orthogonal directions is a second mounting head section having second nozzles. The second mounting head section is rotated such that the second nozzles rotate and successively pickup components from a second component supply table arranged on an opposite side of the board transfer path. These components are then successively mounted onto the board while positioned in the board transfer path.

Description:
This application is a divisional of U.S. application Ser. No. 09/010,490, filed Jan. 21, 1998 and now U.S. Pat. No. 6,789,310, which is a continuation of U.S. application Ser. No. 08/740,992, filed Nov. 5, 1996, which is now U.S. Pat. No. 5,778,525. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to component mounting apparatus and method for automatically mounting a variety of components such as electronic components onto a printed circuit board or the like, and a component mounting equipment including the apparatuses. 
   Generally, in an electronic component mounting apparatus, a number of component supply means are mounted in parallel to one another on a component supply table. In a component mounting stage, the component supply means are successively positioned in a specified component supply position according to a sequence of mounting components while moving the component supply table in a direction in which the component supply means are arranged in parallel. Then, each of the components at the component supply means is taken out by suction by a mounting head section, and the components are transferred to a circuit board positioned in the circuit board positioning section to be subjected to a component mounting process. 
   This type of conventional component mounting apparatus will be described with reference to  FIG. 6  showing a perspective view of it and  FIG. 7  showing a schematic plan view of it. In  FIG. 6 , at the front of an apparatus body  1  is provided a board positioning section  4  for positioning a circuit board P supplied from a board supply means  2  in a mounting position, and the circuit board P mounted with the required components in the board positioning section  4  is discharged by a board discharge means  3 . On the other hand, at the rear of the apparatus body  1  is provided a component supply section  7 , and a rotary type mounting head section  8  is provided between the component supply section  7  and the aforementioned board positioning section  4  as shown in  FIG. 7 . 
   In the component supply section  7 , two component supply tables  10  and  11  are laterally movably provided independently of each other on a guide rail  9 . The component supply tables  10  and  11  are mounted with a number of component supply means  12  arranged in parallel to one another in a direction in which the component supply tables  10  and  11  move. There is illustrated generally a so-called parts cassette as the component supply means  12 , and it will be simply described below. That is, electronic components of an identical type are stored and arranged at regular intervals on a carrier tape while being wound around a reel  13  as covered with a cover tape. By drawing out the carrier tape from the reel  13  to feed at a pitch equal to the storage intervals of the components and taking up the cover tape, the electronic component located at the leading end is positioned in a component supply position A opposite to a component suction head  14  of the mounting head section  8 . 
   Furthermore, as shown in  FIG. 7 , the mounting head section  8  is constructed by providing a plurality of component suction heads  14  at regular angular intervals on an identical circle of a rotary table (not shown) provided rotatably around a vertical axis. Each component suction head  14  is designed to suck a component by vacuum suction means. Upon intermittently rotating the rotary table, it is stopped in steps in the component supply position A and a component mounting position B in order to concurrently perform receiving of each component from the component supply means  12  and mounting of each component onto the circuit board P. While one component supply table  10  is supplying components, the other component supply table  11  that is retreating in a standby position performs changing of component supply means  12  and replenishing of components thereby achieving preparation so that the component mounting apparatus can be operated continuously. 
   In recent years, there has been a growing trend in that the types of circuit boards P to be manufactured and the types of components to be mounted on the circuit boards P are increasing. In order to cope with the above, one solution to be considered is to increase the number of component supply means  12  to be mounted on the component supply tables  10  and  11 . However, in such a case, the component supply tables  10  and  11  are to be elongated sidewise in order to increase the number of component supply means  12 . Consequently, the length of the entire component supply section  7  becomes very long, and this leads to a degraded space utilization efficiency, reducing the productivity per floor area. 
   A more important issue is that the component supply tables  10  and  11  are fed at a pitch in accordance with taking out the components by the mounting head section  8 , and therefore, the following inconvenience occurs. That is, when the component supply tables  10  and  11  increase in weight due to the increase of their lengths, not only is a greater drive power required to move the component supply tables  10  and  11  but also the inertial force of the component supply tables  10  and  11  increases. Therefore, vibration in feeding the component supply tables  10  and  11  at a pitch significantly increases. Consequently, it is impossible to increase the component supply rate, or the component mounting operation speed. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a component mounting apparatus and method capable of increasing the component mounting operation speed without dimensionally increasing the whole apparatus even when the types of boards and the number of components to be mounted on each board increase. 
   In accomplishing these and other objects, according to a first aspect of the present invention, there is provided a component mounting apparatus comprising: 
   a pair of component supply tables on which components are accommodated and which are arranged on both sides of a board mounting position where a board is positioned; 
   a first mounting head section for successively picking up the components at one of the component supply tables and thereafter successively mounting the picked-up components onto the board; and 
   a second mounting head section for successively picking up the components at the other of the component supply tables and thereafter successively mounting the picked-up components onto the board, 
   wherein the first and second mounting head sections are independently operated. 
   According to a second aspect of the present invention, there is provided the component mounting apparatus as described in the first aspect, wherein the first and second mounting head sections are controlled mutually in operation in accordance with a timing at which, when one of them carries out a component picking-up operation for picking up the components from the component supply table, the other of them carries out a component mounting operation for mounting the picked-up components onto the board. 
   According to a third aspect of the present invention, there is provided the component mounting apparatus as described in the first aspect, wherein one of the first and second mounting head section has component suction nozzles sucking the components at one time. 
   According to a fourth aspect of the present invention, there is provided the component mounting apparatus as described in the second aspect, wherein one of the first and second mounting head section has component suction nozzles sucking the components at one time. 
   According to a fifth aspect of the present invention, there is provided a component mounting equipment comprising: 
   a plurality of component mounting apparatuses each of which was described in the description of the first aspect, 
   wherein a board transfer path along which the board is supplied to the board mounting position of the apparatus and discharged from the board mounting position of the apparatus by a board transfer device is provided so that the board transfer path connects the board mounting positions of the component mounting apparatuses, and the component supply tables of the component mounting apparatuses are arranged on both sides of the board mounting positions in the board transfer path. 
   According to a sixth aspect of the present invention, there is provided a component mounting equipment comprising: 
   a plurality of component mounting apparatuses each of which was described in the description of the second aspect, 
   wherein a board transfer path along which the board is supplied to the board mounting position of the apparatus and discharged from the board mounting position of the apparatus by a board transfer device is provided so that the board transfer path connects the board mounting positions of the component mounting apparatuses, and the component supply tables of the component mounting apparatuses are arranged on both sides of the board mounting positions in the board transfer path. 
   According to a seventh aspect of the present invention, there is provided the component mounting equipment as described in the fifth aspect, wherein the components to be mounted onto the single board are all distributed into groups by type, and the components of the groups are accomodated in the component supply tables of the component mounting apparatus as assigned thereto. 
   According to an eighth aspect of the present invention, there is provided the component mounting equipment as described in the sixth aspect, wherein the components to be mounted onto the single board are all distributed into groups by type, and the components of the groups are accommodated in the component supply tables of the component mounting apparatuses as assigned thereto. 
   According to a ninth aspect of the present invention, there is provided a component mounting method comprising steps of: 
   picking up by a first mounting head section components from one of a pair of component supply tables on which the components are accommodated and which are arranged on both sides of a board mounting position where a board is positioned, the first mounting head section successively picking up the components at one of the component supply tables; 
   thereafter successively mounting the components picked up by the first mounting head section onto the board; 
   picking up by a second mounting head section components from the other of the pair of component supply tables, the second mounting head section successively picking up the components at the other of the component supply tables; and 
   thereafter successively mounting the components picked up by the second mounting head section onto the board, 
   wherein the picking-up and mounting steps of the first mounting head section and the picking-up and mounting steps of the second mounting head section are independently carried out. 
   According to a tenth aspect of the present invention, there is provided the component mounting method as described in the ninth aspect, wherein the picking-up step of the first mounting head section and the mounting step of the second mounting head section are carried out at the same time, and the mounting step of the first mounting head section and the picking-up step of the second mounting head section are carried out at the same time. 
   According to an eleventh aspect of the present invention, there is provided the component mounting method as described in the ninth aspect, wherein in a component mounting equipment comprising a plurality of component mounting apparatuses each of which comprises the first and second mounting head sections and the pair of component supply tables between which a board transfer path along which the board is supplied to the board mounting position of the apparatus and discharged from the board mounting position of the apparatus by a board transfer device is provided so that the board transfer path connects the board mounting positions of the component mounting apparatuses, and the component supply tables of the component mounting apparatuses are arranged on both sides of the board mounting positions in the board transfer path, 
   the picking-up and mounting steps of the first mounting head section and the picking-up and mounting steps of the second mounting head section are sequentially carried out. 
   According to a twelfth aspect of the present invention, there is provided the component mounting method as described in the eleventh aspect, wherein the picking-up step of each of the first mounting head sections and the mounting step of each of the corresponding second mounting head sections are carried out at the same time, and the mounting step of each of the first mounting head sections and the picking-up step of each of the corresponding second mounting head sections are carried out at the same time. 
   According to a thirteenth aspect of the present invention, there is provided the component mounting equipment as described in the eleventh aspect, wherein the components to be mounted onto the single board are all distributed into groups by type, and the components of the groups are accommodated in the component supply tables of the component mounting apparatuses as assigned thereto. 
   According to a fourteenth aspect of the present invention, there is provided the component mounting equipment as described in the twelfth aspect, wherein the components to be mounted onto the single board are all distributed into groups by type, and the components of the groups are accommodated in the component supply tables of the component mounting apparatuses as assigned thereto. 
   With the above arrangement, the component supply table is installed fixedly, and therefore, it becomes free of vibration regardless of the number of mounted component supply means which can be mounted thereon. The mounting head section is a robot type which sucks a plurality of components from the component supply table at one time and thereafter successively mounts the components to specified portions of the board. Therefore, even when the number of components to be mounted on a board increases, the component mounting operation speed can be remarkably increased further than in the conventional apparatus in which the component supply table is fed at a pitch with respect to the rotary type mounting head section. 
   Furthermore, components can be mounted by the two of the first and second mounting head sections onto the of the board positioned in a single board mounting position, and therefore, the component mounting operation speed can be further increased. 
   With the above arrangement of the fifth and sixth aspects and the eleventh and twelfth aspects, by mounting different components on the component supply tables installed at each of the component mounting apparatuses, the component supply tables are inevitably arranged on both sides of the board transfer path along it even when the types and the number of components to be mounted onto the board increase. Therefore, the equipment does not dimensionally increase as a whole without expanding significantly in the direction of the board transfer path. Furthermore, the mounting head sections of the component mounting apparatuses operate at high speed and the component supply tables are fixedly installed, and therefore, the component mounting operation speed can be increased. 
   With the above arrangement of the thirteenth and fourteenth aspects, when the types of boards are increased, the equipment can cope with it only by replacing a specified one of the component supply tables installed at the respective component mounting apparatuses with a component supply table mounted with components required type. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects 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: 
       FIG. 1  is a schematic plan view schematically showing component mounting equipment according to an embodiment of the present invention; 
       FIG. 2  is a perspective view of an embodiment of the component mounting apparatus of the present invention, the apparatus being a part of the above equipment; 
       FIG. 3  is a plan view of an operating mechanism section of the above apparatus; 
       FIG. 4  is a flow chart of the above apparatus; 
       FIG. 5  is a block diagram showing construction for performing the control operation of the apparatus; 
       FIG. 6  is a perspective view of a conventional component mounting apparatus; and 
       FIG. 7  is a schematic plan view of the above conventional apparatus. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   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. 
   An embodiment of the present invention will be described below with reference to  FIGS. 1 through 4 . 
     FIG. 1  is a schematic plan view schematically showing component mounting equipment (component mounting line) according to an embodiment of the present invention. In the figure, four component mounting apparatuses  27 A through  27 D are provided along a board transfer path  21 , and four board transfer means  22  are provided for the component mounting apparatuses  27 A through  27 D along the board transfer path  21  in the lateral direction so that each board transfer means  22  supplies a board to be mounted with components to a board mounting position of one of the component mounting apparatuses and discharges the board therefrom. The component mounting apparatuses  27 A through  27 D have an identical basic structure, and therefore, the component mounting apparatus  27 D is taken as an example to be described below with reference to  FIG. 2  that shows a perspective view of it and  FIG. 3  that shows a plan view of its operating mechanism section. 
   In the component mounting apparatus  27 D shown in  FIG. 2 , a laterally provided pair of inverted U-shaped support frames  29  are arranged in parallel to each other along the board transfer path  21  while allowing the board transfer path  21  to penetrate them. Between both the support frames  29  are arranged two operating frames  30  in parallel to each other across the frames  29 . The operating frames are supported individually movably in a direction perpendicular to the board transfer path  21 . To each operating frame  30  is mounted a mounting head section  31  movably along the operating frame  30 . At the mounting head section  31 , four component suction nozzles  33  are provided at regular intervals (at intervals of 90°) around a rotary member  32  that is rotatably supported around a horizontal axis. Upon rotating the rotary member  32  at a pitch equal to each interval of the component suction nozzles  33 , the component suction nozzles  33  are selectively and sequentially directed downward to suck a component  34  from a component supply table  28 A and mount the sucked component  34  onto a circuit board  37  located at the board mounting position where the board  37  is positioned by a board positioning section  24 . 
   Between both the support frames  29  are inserted the component supply tables  28 A from both depthwise sides  20  as moved by casters  40 , and thereafter they are fixedly installed in specified positions. The component supply table  28 A is provided with component supply means  12  comprised of parts cassettes provided with the aforementioned reels  13 . Other than this, as shown in  FIG. 25   1 , a component supply table  28 B mounted with a stick-shaped component supply means  38  at which components stored in a pipe member are successively fed to a take-out position, a component supply table  28 C on which bulk components  39  are placed, and a tray-shaped component supply table  28 D are installed at the component mounting apparatuses  27 A through  27 D. It is to be noted that the tray-shaped component supply table  28 D is provided with a mounting head section  59  having a pivot arm shape for taking out the components thereof. 
   In  FIG. 3 , each operating frame  30  houses therein a head positioning mechanism section  41  for moving the mounting head section  31  in the lengthwise direction of the board transfer path  21 . 
   The head positioning mechanism section  41  is comprised of a ball thread  43  that is rotatably supported across a pair of support plates  42  fixed to both ends of each operating frame  30 , a step motor  47  for rotatively driving the ball thread  43  via a connecting means  44 , and a moving member  49  in which a nut  48  meshed with the ball  20  thread  43  is internally fixed and moved in accordance with the rotation of the ball thread  43 . The mounting head section  31  is fixed to the moving member  49  via a head holder  50 , and the head holder  50  is internally provided with a known head elevation mechanism section  51  for vertically moving the mounting head section  31 . 
   Each of the support frames  29  houses therein a head feed mechanism section  52  for moving the head positioning mechanism section  41  via each operating frame  30  in a direction perpendicular to the board transfer path The head feed mechanism section  52  is comprised of a ball thread  54  that is rotatably supported across a pair of support plates  53  fixed to both ends of each support frame  29 , a step motor  56  for rotatively driving the ball thread  54  via a connecting means  55 , a moving member  57  that is fixed to an end portion of each operating frame  30  as meshed with the ball thread  54  and operates to move the operating frame  30  in accordance with the rotation of the ball thread  54 , and a guide shaft  58  that is fixed across the support plates  53  and operates to slidably support the operating frame  30  while allowing the guide shaft  58  to penetrate the other end of the operating frame  30 . A controller  100  controls the operations of the apparatuses  27 A– 27 D and the board transfer means  22 , because it is connected to them as shown in  FIG. 5  in which the connection structure of the apparatus  27 B is shown as one example. The other connection structure of the apparatuses  27 A,  27 C, and  27 D are similar to the apparatus  27 B. 
   The operation of the aforementioned component mounting equipment will be described next with reference to a flowchart of  FIG. 4 . In the component mounting apparatuses  27 A through  27 D, the mounting head sections  31  are controlled in accordance with a timing at which, while one mounting head section  31  is sucking components  34  from one of the component supply tables  28 A through  28 D, the other mounting head section  31  mounts the components  34  onto the circuit board  37 . Since both the mounting head sections  31  execute an identical operation except for an operating timing shift, only the operation of one mounting head section  31  will be now described. 
   First, the mounting head section  31  is moved to a position just above the component  34  to be sucked by suction on one of the component supply tables  28 A through  28 D and then positioned (step S 1 ). That is, upon rotating the step motor  47  of the head positioning mechanism section  41  by a specified angle in the required rotational direction, the moving member  49  moves in the lengthwise direction of the board transfer path  21  by the ball thread  43  that is rotating integrally with the step motor  47 , and the mounting head section  31  is moved to a specified component take-out position on the one of the component supply tables  28 A through  28 D. In this stage, in regard to the other component supply tables  28 A through  28 C except for the tray-shaped component supply table  28 D, the component take-out position is positioned in a straight line extending along the board transfer path  21 . Consequently, the mounting head section  31  does not move as positioned in the position until such components as the parts cassette or the stick fronting the mounting head section  31  deplete. 
   When the mounting head section  31  is positioned, the head elevation mechanism section  51  operates to move down the mounting head section  31 , the component suction nozzle  33  sucks a component  34 , and thereafter the mounting head section  31  is slightly moved up by the head elevation mechanism section  51  (step S 2 ). Subsequently, the rotary member  32  of the mounting head section  31  is rotated by one pitch, and the next component suction nozzle  33  is made to front the component take-out position (step S 3 ). In this stage, it is decided whether or not the mounting head section  31  has completed the suction of a specified number (four in this embodiment) of components  34  (step S 4 ). If it has not been completed, the same operation as above will be repeated to suck the specified number of components  34 . 
   When the suction of the specified number of components  34  has been completed, the step motor  56  of the head feed mechanism section  52  and the step motor  47  of the head positioning mechanism section  41  are simultaneously driven to move the mounting head section  31  onto the board positioning section  24  via the operating frame  30  in accordance with the rotation of the ball thread  54  and then position it just above a specified component mounting position of the circuit board  37  by the head positioning mechanism section  41  (step S 5 ). Then, the head elevation mechanism section  51  is driven to mount the components that have been held by the component suction nozzle  33  as sucked thereto onto the circuit board  37  (step S 6 ). After the mounting head section  31  is slightly moved up by the head elevation mechanism section  51 , the mounting head section  31  is moved to a position just above the next component mounting position of the circuit board  37  and then positioned by the operations of the head positioning mechanism section  41  and the head feed mechanism section  52 , and the rotary member  32  is rotated by one pitch, so that the component to be mounted next is made to front the component mounting position (step S 7 ). 
   In this stage, it is decided whether or not the mounting of all the components  34  that have been held by the mounting head section  31  as sucked thereto has been completed (step S 8 ). If it has not been completed, the same operation as above will be repeated to mount all the components  34  onto the specified positions of the circuit board  37 . 
   When the specified number of components has been completed at step S 8 , it is decided whether or not the mounting of all the components  34  distributed to the component mounting apparatuses  27 A through  27 D for the circuit board  37  positioned in the board positioning section  24  has been completed (step S 9 ). If it has not been completed, the mounting head sections  31  are moved again above the component supply tables  28 A through  29 D to repeat the suction of the components  34  from the component supply tables  28 A through  28 D and the mounting of the components  34  onto the circuit board  37  in a manner similar to the above until the mounting of all the components  34  onto the circuit board  37  is completed. When the mounting of all the components  34  onto the circuit board  37  is completed, each circuit board  37  positioned in the board transfer path  21  is fed by a specified pitch to be positioned in the board positioning sections  24  of the component mounting apparatuses  27 A through  27 D for the next process (step S 10 ), and an operation similar to the above will be repeated. 
   In the above component mounting equipment, mutually different components can be mounted on the component supply tables  28 A through  28 D of the plurality (four in this embodiment) of component mounting apparatuses  27 A through  27 D provided in parallel to one another along the board transfer path  21 . Therefore, when the types and the number of components  34  to be mounted onto the circuit  25  board  37  increase, these components are mounted on the component supply tables  28 A through  28 D as distributed into groups classified by type. With this arrangement, since the component supply tables  28 A through  28 D are mounted with only the components  34  of the respective groups, the tables are not dimensionally increased. Furthermore, since the component supply tables  28 A through  28 D are installed perpendicularly to the board transfer path  21  at the component mounting apparatuses  27 A through  27 D, the equipment is not dimensionally increased as a whole without significantly expanding in the direction of the board transfer path  21 . 
   Furthermore, since the mounting head section  31  of the component mounting apparatuses  27 A through  27 D only operates and the component supply tables  28 A through  28 D are fixedly installed, the tables become free of vibration regardless of the number of mounted component supply means  12  and  38 . Furthermore, the mounting head section  31  sucks at one time a plurality of components  34  from the component supply tables  28 A through  28 D and successively mounts the 20 components  34  onto the specified portions of the circuit board  37 . Furthermore, the component mounting apparatuses  27 A through  27 D are each provided with a pair of mounting head sections  31  and controls the mounting head sections  31  so that, while one is sucking components  34 , the components  34  that are held by the other as sucked thereto are mounted to the circuit board  37 . With the above arrangement, even when the types and the number of components  34  to be mounted onto the circuit board  37  increase, the component mounting operation speed can be remarkably increased further than in the conventional apparatus in which the component supply table is fed at a pitch with respect to the rotary type mounting head section. 
   When the types of circuit boards  37  increase, it can be coped with only by replacing a part of the component supply tables  28 A through  28 D installed at the component mounting apparatuses  27 A through  27 D with component supply tables  28 A through  28 D mounted with required components  34 . It is to be noted that the component mounting apparatuses  27 A through  27 D can be also used singly. 
   According to the present invention as described above, there is provided a robot type mounting head section in which the component supply tables are installed fixedly, and a plurality of components are sucked at one time from the component supply tables and thereafter transferred to be successively mounted onto the specified portions of the board. With this arrangement, even when the number of components to be mounted onto the board increases, the component mounting operation speed can be remarkably increased further than in the conventional structure in which the component supply table is fed at a pitch with respect to the rotary type mounting head section. Furthermore, since the laterally provided pair of first and second mounting head sections are mutually controlled in operation in accordance with a timing at which, when one is located on the component supply table, the other is located on the board positioning section. With this arrangement, components can be mounted onto a single board by a plurality of mounting head sections, and therefore, the component mounting operation speed can be further increased. 
   Furthermore, according to the component mounting equipment of the present invention, by mounting mutually different components onto the component supply tables of the component mounting apparatuses arranged in parallel to one another, even when the types and the number of components to be mounted onto the circuit board increase, the equipment is not dimensionally increased as a whole without significantly expanding in the direction of the board transfer path. Furthermore, the component mounting operation speed can be further increased. In this case, there may be provided the structure in which all the components to be mounted onto single board are distributed into groups by type and the components of each group are mounted on component supply tables as assigned to them installed at the respective component mounting apparatuses. With this arrangement, when the types of boards increase, it can be coped with onlly by replacing a part of the component supply tables of the component mounting apparatuses with component supply tables mounted with the required components. 
   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 are 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 claims unless they depart therefrom.