CIRCUIT BOARD HOLDING APPARATUS AND CIRCUIT BOARD HOLD RELEASING METHOD

Abstract: In a stage of moving downward a movable member (14) after gripping a printed board (2) by a stationary member (13) and the movable member (14) in the direction of thickness of the board and mounting electronic components, separation mechanism (7, 12) which compulsorily separates the circuit board from the stationary member (13) is provided, thereby preventing the occurrence of a state in which the printed board (2) is stuck to the stationary member.

Description: DESCRIPTION CIRCUIT BOARD HOLDING APPARATUS AND CIRCUIT BOARD HOLD RELEASING METHOD TECHNICAL FIELD The present invention relates to a circuit board holding apparatus which is provided for a component mounting apparatus for mounting, for example, electronic components onto a circuit board such as a printed board and executes holding and releasing the hold of the circuit board and to a circuit board hold releasing method executed by the circuit board holding apparatus. BACKGROUND ART In a component mounting apparatus for mounting electronic components onto a printed board, a portion which executes securing and holding of the printed board in the stage of mounting the electronic components is constructed as follows. That is, as shown in Figs. 7 and 8, a circuit board holding apparatus 1 for securing and holding a printed board 2 is provided on an X-Y table for moving the printed board 2 in X- and Y-directions. On the circuit board holding apparatus 1 is fixed a pair of stationary members 13 which extend parallel to the X- 7/49272 PC17JP97/02103 direction and have an approximately inverted L-like sectional shape, and a pair of movable members 14 which extend in the X-direction along inner side surfaces 13a which belong to both the stationary members 13 and oppose each other at both the stationary members 13 and slide in a Z-direction between a board gripping position 20 and a board releasing position 21 while being guided along the inner side surfaces 13a are provided. In such a circuit board holding apparatus 1, the printed board 2 is conveyed into a region between both the stationary members 13. Then, by moving upward both the movable members 14 into the board gripping position 20 by means of drive units 15 having, for example, an air cylinder, the edge portions 2a of the printed board 2 extending in the X-direction are gripped by board contact surfaces 13b of the stationary members 13 and board contact surfaces 14b of the movable members 14, so that the printed board 2 is secured to the circuit board holding apparatus 1. The X-Y table on which the printed board 2 is secured in this manner is moved into a specified position in the X- and Y-directions, and mounting of electronic components onto the printed board 2 is executed by an electronic component mounting unit 3. After the operation of mounting specified electronic components onto the printed board 2 is completed, the drive units 15 are operated to move the movable members 14 downward to the board releasing position 21 as shown in Fig. 9, where the gripping of the printed board 2 is released and the printed board 2 is conveyed to the next process. However, in the aforementioned circuit board holding apparatus 1, there may occur a phenomenon that the printed board 2 sticks to the stationary members 13 as shown in Fig. 10 depending on the surface conditions of the printed board 2 in spite of the fact that the movable members 14 have been moved down to the board releasing position 21. That is, it is sometimes the cases where a rubber material is attached or coated on the board contact surface 13b of the stationary member 13 and the board contact surface 14b of the movable member 14 for the purpose of increasing the frictional force between the stationary member 13 and the movable member 14 and the printed board 2 so that the displacement of the printed board 2 should not occur in the X-direction in the state in which the printed board 2 is gripped. Therefore, in the case where a flux is coated on the front and rear surfaces of the printed board 2 or in a similar case, it may be the case where the aforementioned rubber material and the front and rear surfaces of the printed board 2 stick to each other due to the aforementioned gripping operation. After such a stuck state has occurred, the printed board 2 falls onto the movable members 14 side by its own gravity, however, this disadvantageously causes a state in which the positions of the electronic components mounted on the printed board 2 are displaced by the falling of the printed board 2, a state in which the printed board 2 cannot be conveyed to the next process or a similar state. DISCLOSURE OF INVENTION The present invention has been developed to solve the above issue and provide a circuit board holding apparatus which prevents the occurrence of displacement of the mounted electronic components and the state in which the printed board cannot be conveyed to the next process after the electronic components have been mounted onto the circuit board and a circuit board hold releasing method to be executed by the circuit board holding apparatus. In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided a circuit board holding apparatus for holding a circuit board by gripping a pair of opposed edge portions of a circuit board, comprising: stationary members which are arranged oppositely to the edge portions and contact a front surface of the circuit board; movable members which contact a rear surface of the circuit board and grip each of the edge portions of the circuit board between the movable member and the stationary member in a direction of thickness of the circuit board by moving into a board gripping position, the movable members moving in the direction of thickness of the circuit board between the board gripping position and a board releasing position; and a separation mechanism for compulsorily separating the circuit board from the stationary members when the movable members move from the board gripping position to the board releasing position in a stage of releasing the hold of the circuit board. According to a second aspect of the present invention, there is provided a circuit board holding apparatus as defined in the first aspect, wherein the separation mechanism is a pressing member which is mounted to the stationary member and puts the circuit board into pressure contact with the movable member. According to a third aspect of the present invention, there is provided a circuit board holding apparatus as defined in the second aspect, wherein, when the front and rear surfaces of the circuit board are located upward and downward and the movable member moves in a vertical direction, the pressing member is an elastic member having one end portion to be fixed to the stationary member and the other end portion which is to contact the front surface of the circuit board and presses the circuit board against the movable member. According to a fourth aspect of the present invention, there is provided a circuit board holding apparatus as defined in the first aspect, wherein the separation mechanism is a suction unit having a suction section which is arranged on the rear surface side of the circuit board and attracts by suction the rear surface of the circuit board and a drive unit which moves the suction section in a direction in which the movable member moves together with the moving of the movable member. According to a fifth aspect of the present invention, there is provided a circuit board holding apparatus as defined in the fourth aspect, further comprising a control unit which controls start of the moving of the movable member from the board gripping position into the board releasing position, start of the sucking of the circuit board by the suction unit, and the moving of the suction section by means of the drive unit. According to a sixth aspect of the present invention, there is provided a circuit board hold releasing method to be executed by a circuit board holding apparatus which grips a pair of opposed edge portions of a circuit board in a direction of thickness of the circuit board by means of a stationary member and a movable member moving between a board gripping position and a board releasing position, thereby holding the circuit board, comprising: moving the movable member into the board releasing position in a stage of releasing the gripping of the circuit board; and making the circuit board contact the movable member together with the moving of the movable member toward the board releasing position side. BRIEF DESCRIPTION OF DRAWINGS 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: Fig. 1 is a perspective view showing the total construction of a circuit board holding apparatus according to an embodiment of the present invention; Fig. 2 is a side view showing a state in which a pressing member shown in Fig. 1 is mounted to a stationary member; Fig. 3 is a side view showing a state in which movable members are arranged in a board gripping position in the circuit board holding apparatus shown in Fig. l; Fig. 4 is a side view showing a state in which the movable members are arranged in a board releasing position in the circuit board holding apparatus shown in Fig. 1; Fig. 5 is a side view showing a circuit board holding apparatus according to a second embodiment of the present invention in a state in which movable members are arranged in a board gripping position; Fig. 6 is a side view showing a state in which the movable members are arranged in a board releasing position in the circuit board holding apparatus shown in Fig. 5; Fig. 7 is a perspective view showing the total construction of a prior art circuit board holding apparatus; Fig. 8 is a side view showing a state in which movable members are arranged in a board gripping position in the circuit board holding apparatus shown in Fig. 7; Fig. 9 is a side view showing a state in which movable members are arranged in a board releasing position in the circuit board holding apparatus shown in Fig. 7; and Fig. 10 is a side view showing a state in which a printed board is stuck to the stationary member side in the circuit board holding apparatus shown in Fig. 7. BEST MODE FOR CARRYING OUT THE INVENTION 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. A circuit board holding apparatus and a circuit board hold releasing method according to an embodiment of the present invention will be described below with reference to the drawings. It is to be noted that the circuit board hold releasing method is executed by the circuit board holding apparatus. Further, identical components are denoted by the same reference numerals in the figures. As shown in Fig. 1, on upper surfaces 13c of the stationary members 13 of a circuit board holding apparatus 100 of the present embodiment are mounted totally four L-shaped pressing members 7, two of which arranged on one and two of which arranged on the other one of the surfaces 13c, so that they are located at the four corners of the printed board 2 corresponding to an example of the circuit board in the aspects of the present invention. It is to be noted that the pressing member 7 corresponds to an example of the separating mechanism in the aspects of the present invention. The pressing member 7 is an elastic member formed by integrating a fixation section 71 with a contact section 72 which bends toward the printed board 2 side with respect to the fixation section 71 as shown in Fig. 2. The fixation section 71 has a length slightly greater than a width dimension W of the upper surface 13c, and as described later, it extends as contacted the upper surface 13c when the movable member 14 is in the board releasing position 21. Such a fixation section 71 is mounted to the upper surface 13c of the stationary member 13 by means of a screw 8 at one end portion 7a of the pressing member 7 located on the opposite side to the contact section 72. Therefore, the pressing member 7 is fixed to the stationary member 13. The contact section 72 extends downward by a dimension L beyond the board contact surface 13b of the stationary member 13. Therefore, as described later, when the movable member 14 is located near the board gripping position 20, the other end portion 7b of the pressing member 7 contacts the front surface 2b of the printed board 2 arranged on the upper side. The operation of the pressing members 7 constructed as above will be described below. Similarly to the aforementioned prior art, after the printed board 2 is conveyed into the region between the stationary members 13 , the movable members 14 are moved upward by the operation of drive units 15, and the edge portions 2a of the printed board 2 are gripped by the board contact surfaces 13b of the stationary members 13 and the board contact surfaces 14b of the movable members 14 as shown in Fig. 3. The pressing member 7 has its one end portion 7a fixed to the stationary member 13 by means of the screw 8 and has the other end portion 7b protruded by the dimension L below the board contact surface 13b. Therefore, the front surface 2b of the printed board 2 and the other end portion 7b contacts each other just before the edge portion 2a of the printed board 2 is completely gripped. When the printed board 2 is completely gripped by the stationary member 13 and the movable member 14, the fixation section 71 of the pressing member 7 warps upward with the point fixed by the screw 8 served as a fulcrum. Therefore, in the state in which the printed board 2 is gripped by the stationary member 13 and the movable member 14, the other end portion 7b is pressing downward the front surface 2b of the printed board 2, i.e., toward the movable member side by the elastic force owned by the pressing member 7. Similarly to the prior art, after the electronic components are mounted to the printed board 2 as described above, the movable members 14 move downward with the left and right drive units 15 synchronized with each other in operation. In this stage, the two edge portions 2a of the printed board 2 are compulsorily pressed toward the movable member side by the other end portions 7b of the pressing members 7. Therefore, even when the front surface 2b of the printed board 2 is in the state in which it is stuck to the board contact surfaces 13b of the stationary members 13, the stuck state is released by the pressure forces of the pressing members 7, so that the stationary members 13 and the printed board 2 are separated from each other. Therefore, as shown in Fig. 4, the printed board 2 moves downward together with the movable members 14 in a state in which it is compulsorily made to contact the movable members 14. By thus providing the pressing members 7, the state in which the printed board 2 remains stuck to the board contact surfaces 13b of the stationary members 13 in spite of the fact that the movable member 14 has moved down can be prevented from occurring. Therefore, the phenomenon that the positions of the mounted electronic components are displaced by the subsequent falling of the printed board 2 onto the movable members 14 and the phenomenon that a trouble occurs in conveying the printed board 2 to the next process can be prevented from occurring. The aforementioned pressure force of the pressing member 7 can be varied according to the design conditions of the material, thickness, aforementioned dimension L and the like of the pressing member 7, and it is proper to set the above design conditions to appropriate values according to the adhesion force exerted between the printed board 2 and the stationary member 13. Furthermore, the pressing member 7 is arranged in the positions corresponding to the four corners of the printed board 2 in the present embodiment as shown in Fig. 1. However, being not limited to this, the pressing member 7 may be arranged continuously along the edge portion 2a of the printed board 2. Furthermore, the pressing member 7 has the L- like leaf spring configuration as illustrated in the present embodiment, however, the member 7 is not limited to this. That is, the member 7 is only required to be an elastic member having one end portion to be fixed to the stationary member 13 and the other end portion which is to contact the front surface 2b of the printed board 2 and presses the printed board 2 toward the movable member 14. There can be considered a structure provided by a coil spring for performing the aforementioned pressing operation by the elastic force of the spring, or a structure using an elastic material such as a rubber material and the like. Furthermore, it is acceptable to adopt a mechanism in which the one end portion is mounted to a member other than the stationary member 13 and the other end portion contacts the printed board 2 and presses the printed board 2 toward the movable member 14, i.e., a separation mechanism for separating the printed board 2 from the stationary member 13. Furthermore, the front surface 2b of the printed board 2 is arranged on the upper side and the rear surface 2c is arranged on the lower side in the present embodiment. However, it is acceptable to arrange the front and rear surfaces 2b and 2c of the printed board 2 parallel to the vertical direction and grip the printed board 2 laterally with respect to the vertical direction by the stationary member 13 and the movable member 14. Next, a circuit board holding apparatus 101 according to a second embodiment will be described below. In this embodiment, in order to compulsorily make the printed board 2 contact the movable member 14 when the movable member 14 is moved downward in the stage of releasing the hold of the printed board 2 , a suction unit 12 for attracting by suction the rear surface 2c of the printed board 2 is provided as another example of the separation mechanism in place of the aforementioned pressing members 7. A concrete description will be made. On the rear surface side of the printed board 2 on the X-Y table is provided the suction unit 12 for attracting by suction a suction area which does not interfere the mounting of electronic components onto the printed board 2. As the above suction area, for example, the four corners, a center portion or the like of the printed board 2 can be used. It is to be noted that the suction area is only one center portion of the printed board 2 in this embodiment. The suction unit 12 is provided with a suction pad 120 for attracting by suction the suction area of the printed board 2, a drive unit 121 having, for example, an air cylinder for moving the suction pad 120 upward and downward, and a vacuum unit 123 which is connected to the suction pad 120 by means of a suction hose and executes a suction operation. Further, in order to make the operation of the drive units 15 for vertically moving the movable members 14 synchronize with the operation of the drive unit 121 for vertically moving the suction pad 120 and control the suction operation, a control unit 122 to be electrically connected to the drive units 15, the drive unit 121, and the vacuum unit 123 is provided. It is to be noted that the control unit 122 is not shown in Fig. 6. The operation of the circuit board holding apparatus 101 of the second embodiment having the above construction will be described below. Similarly to the aforementioned case, after the printed board 2 has been gripped by the stationary member 13 and the movable member 14 and mounted with electronic components, the suction pad 120 moves upward until it will be made to contact the rear surface 2c of the printed board 2 by the operation of the drive unit 121 before the movable members 14 will be moved downward by the operation of the drive units 15. Then, before the movable members 14 are moved downward or simultaneously with the start of the downward movement, the suction of the printed board 2 is started by the vacuum unit 123. Thus, by starting the suction of the printed board 2, the printed board 2 is compulsorily made to contact the movable members 14. It is to be noted that the operations of the drive units 15 for the movable members 14, the drive unit 121 for the suction pad 120, and the vacuum unit 123 are controlled by the control unit 122. Therefore, even when the front surface 2b of the printed board 2 is in the state in which it is stuck to the board contact surfaces 13b of the stationary members 13, the stuck state is released by the suction force of the vacuum unit 123. Consequently, as shown in Fig. 6, the printed board 2 moves downward together with the movable members 14 in the state in which the printed board 2 is compulsorily made to contact the movable members 14. It is to be noted that the suction operation of the printed board 2 is stopped under the control of the control unit 122 at the point of time when the movable members 14 have moved downward by a specified distance from the board gripping position 20 into the board releasing position 21 or after they have completed the downward movement into the board releasing position 21. By thus providing the suction unit 12, the printed board 2 can be prevented from falling onto the movable members 14, so that the displacement of the arrangement of the already mounted electronic components and the occurrence of a trouble in conveying the printed board 2 to the next process can be prevented. It is also acceptable to arrange the front and rear surfaces 2b and 2c of the printed board 2 parallel to the vertical direction and grip the printed board 2 laterally with respect to the vertical direction by the stationary member 13 and the movable member 14 in this second embodiment. The movable members 14 are driven by the respective drive units 15. However, being not limited to this, both the movable members 14 may be driven by one drive unit. Furthermore, as another embodiment of the separation mechanism, it is acceptable to adopt a mechanism in which, for example, a pawl member to be engaged with the printed board 2 is provided and the printed board 2 is compulsorily made to contact the movable members 14 by engaging the pawl member with the printed board 2 when releasing the hold of the printed board 2, i.e., a mechanism in which the printed board 2 is compulsorily separated from the stationary members 13. As described in detail above, according to the circuit board holding apparatus of the aspects of the present invention and the circuit board hold releasing method of the aspects of the present invention, there is provided the separation mechanism for compulsorily separating the circuit board from the stationary member when the movable member moves from the board gripping position to the board releasing position in the stage of releasing the hold of the circuit board achieved by the stationary member and the movable member. With this arrangement, even when the circuit board is in the state in which it is stuck to the stationary member, the circuit board is compulsorily released from the stuck state and moved downward together with the movable member. Therefore, the stationary member does not fall onto the movable member after the movable member has moved downward to the board releasing position, so that the displacement of the positions of the electronic components mounted on the circuit board or the state in which the circuit board cannot be conveyed to the next process can be prevented from occurring. The entire disclosure of Japanese Patent Application No. 8-161951 filed on June 21, 1996, including specification, claims, drawings, and summary are incorporated herein by reference in its entirety. 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 appended claims unless they depart therefrom.

Claims: CLAIMS 1. A circuit board holding apparatus for holding a circuit board by gripping a pair of opposed edge portions (2a) of a circuit board (2) , comprising: stationary members (13) which are arranged oppositely to the edge portions and contact a front surface of the circuit board; movable members (14) which contact a rear surface of the circuit board and grip each of the edge portions of the circuit board between the movable member and the stationary member in a direction of thickness of the circuit board by moving into a board gripping position (20) , the movable members moving in the direction of thickness of the circuit board between the board gripping position and a board releasing position (21) ; and a separation mechanism (7, 12) for compulsorily separating the circuit board from the stationary members when the movable members move from the board gripping position to the board releasing position in a stage of releasing the hold of the circuit board. 2. A circuit board holding apparatus as claimed in Claim 1, wherein the separation mechanism is a pressing member (7) which is mounted to the stationary member and puts the circuit board into pressure contact with the movable member. 3. A circuit board holding apparatus as claimed in Claim 2, wherein, when the front and rear surfaces of the circuit board are located upward and downward and the movable member moves in a vertical direction, the pressing member is an elastic member having one end portion (7a) to be fixed to the stationary member and the other end portion (7b) which is to contact the front surface of the circuit board and presses the circuit board against the movable member. 4. A circuit board holding apparatus as claimed in Claim 1, wherein the separation mechanism is a suction unit (12) having a suction section (120) which is arranged on the rear surface side of the circuit board and attracts by suction the rear surface of the circuit board and a drive unit (121) which moves the suction section in a direction in which the movable member moves together with the moving of the movable member. 5. A circuit board holding apparatus as claimed in Claim 4, further comprising a control unit (122) which controls start of the moving of the movable member from the board gripping position into the board releasing position, start of the sucking of the circuit board by the suction unit, and the moving of the suction section by means of the drive unit. 6. A circuit board hold releasing method to be executed by a circuit board holding apparatus which grips a pair of opposed edge portions (2a) of a circuit board (2) in a direction of thickness of the circuit board by means of a stationary member (13) and a movable member (14) moving between a board gripping position (20) and a board releasing position (21) , thereby holding the circuit board, comprising: moving the movable member into the board releasing position in a stage of releasing the gripping of the circuit board; and making the circuit board contact the movable member together with the moving of the movable member toward the board releasing position side.

Inventors: ISHITANI YASUYUKI, SENO MAKITO, ISHITANI, YASUYUKI, SENO, MAKITO
Applicants: ISHITANI YASUYUKI, MATSUSHITA ELECTRIC IND CO LTD, SENO MAKITO, ISHITANI, YASUYUKI, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., SENO, MAKITO
Application year: 1997
Main classification: H05K13
IPC codes: H05K13