Abstract:
An exchanger for a tray feeder is provided which can easily and stably grasp and move a tray plate loaded with electronic parts using a suction force. A plurality of vacuum pads are provided on a moveable nozzle support unit of the exchanger. The vacuum pads are mounted on a plurality of suction nozzles along the surface of the nozzle support unit. A plurality of stoppers are interspersed between pairs of adjacent suction nozzles. These stoppers stably and precisely position the tray plate while it is grasped by the suction nozzles and moved through the action of the nozzle support unit.

Description:
[0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 10/061,410, which claims priority to Korean Patent Application No. 35776/2001 filed Jun. 22, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an exchanger for a tray feeder, and in particular to an improved exchanger for a tray feeder which can retrieve or return a tray on which an electronic part is mounted to or from a magazine.  
           [0004]    2. Background of the Related Art  
           [0005]    Referring to FIGS. 1 and 2, in a conventional electronic parts feeder for feeding electronic parts on a tray, a magazine  3  receiving the electronic parts  4  is supported by a lifter  7 , and is lifted or lowered along a ball screw  6  driven by a driving motor  5 .  
           [0006]    When a required type of electronic parts  4  is selected, the lifter  7  is moved in an upward or downward direction. The magazine  3  receiving a tray plate  2  is supported on the lifter  7 . After a position of the lifter  7  is decided, the tray plate  2  received in the magazine  3  is grasped and transferred by driving of a tray plate fetch unit  8 .  
           [0007]    Thereafter, the electronic parts  4  are moved to the upper portion of a centering table  11  by a moving unit  10  having a moving nozzle  9 . The centering table  11  on which the electronic parts  4  are placed is moved to the mounter side, thereby supplying the electronic parts  4 .  
           [0008]    However, the conventional electronic parts feeder has a disadvantage in that, when the tray plate fetch unit  8  is driven to grasp and fetch the tray plate  2  received in the magazine  3  during the operation of the mounter, the tray plate  2  received in the magazine  3  can not maintain a constant position due to a shaking action caused by the driving of the electronic parts feeder. As a result, the tray plate fetch unit  8  incompletely or imprecisely grasps the tray plate  2 , and thus the electronic parts  4  mounting process cannot be properly performed.  
           [0009]    The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.  
         SUMMARY OF THE INVENTION  
         [0010]    An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.  
           [0011]    Another object of the present invention is to provide an exchanger for a tray feeder which can easily grasp a tray plate loaded with electronic parts using a suction force applied by a plurality of vacuum pads of a nozzle support unit, which can stably and precisely position the tray plate while it is grasped and moved, and which can stably and precisely replace the tray plate.  
           [0012]    In order to achieve the above-described object of the invention, there is provided (claim language)  
           [0013]    Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The invention will be described in detail with reference to the following drawings, in which like reference numerals refer to like elements, and wherein:  
         [0015]    [0015]FIG. 1 is a perspective view of a tray and a magazine of an electronic parts feeder in accordance with the conventional art;  
         [0016]    [0016]FIG. 2 is a perspective view of an electronic parts feeder in accordance with the conventional art;  
         [0017]    [0017]FIG. 3 is a perspective view of a tray feeder having an exchanger in accordance with an embodiment of the present invention;  
         [0018]    [0018]FIG. 4 is a rear-perspective view of a main frame of the tray feeder of FIG. 3;  
         [0019]    [0019]FIG. 5 is a perspective view of the exchanger of FIG. 3; and  
         [0020]    [0020]FIG. 6 is a perspective view of a nozzle support unit of the exchanger shown in FIG. 5.  
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0021]    An exchanger for a tray feeder in accordance with an embodiment of the invention will now be described in detail with reference to FIGS.  3  to  5 .  
         [0022]    The tray feeder (referred to as ‘electronic parts feeder’) of the present invention includes an exchanger  100  for retrieving or replacing a plurality of tray plates  450 , a stacker  200 , a magazine  300  and a transfer  400 . The stacker  200  includes a cover frame  210  and a main frame  220 . The cover frame  210  has a plurality of horizontal frames  211 , longitudinal frames  212  and vertical frames  213  surrounding an outer portion thereof A base unit  214  is formed at the lower portion of the vertical frames  213 .  
         [0023]    As illustrated in FIGS. 3 and 4, the transfer  400  and the exchanger  100  are connected at the upper portion of the main frame  220  positioned at one side portion of the cover frame  210 . A motor  215  is installed at one side portion of the upper portion of a support frame  217 , which is positioned at one side portion of the main frame  220 . A ball screw  216  is connected to a motor shaft (not shown) of the driving motor  215 . Since the ball screw  216  is connected to one side portion of an elevator  240 , when the ball screw  216  is operated by driving the driving motor  215 , the elevator  240  moves in a predetermined direction.  
         [0024]    A plurality of Linear Motion (LM) guides  218  for guiding the elevator  240  positioned on the base unit  214  are installed at one side portion of the support frame  217 . A plurality of guide blocks  232  connected to one side portion of the elevator  240  are inserted into the plurality of LM guides  218 . Other portions of the guide blocks  232  are connected to one side portion of the guide frame  230  connected to the elevator  240 , thereby lifting or lowering the elevator  240 .  
         [0025]    A plurality of electronic parts (see FIG. 1) are mounted on the plurality of trays  460  in the magazine  300 . The plurality of trays  460  are mounted on a plurality of tray plates  450 . First and second plates  430  and  440 , respectively, for transferring the tray plates  450  are positioned at opposite end portions of the upper portion of the transfer  400  at a predetermined interval, and a driving unit  442  formed at one side portion of the transfer  400  to drive the first and second plates  430  and  440 , respectively.  
         [0026]    [0026]FIG. 5 is a perspective view illustrating the exchanger of FIG. 3, and FIG. 6 is an enlarged perspective view illustrating the nozzle support unit of the exchanger. The exchanger  100  includes a nozzle support unit  110 , a guide support unit  120 , a driving unit  130 , a guide block  150 , and a head block  140 . The guide support unit  120  includes a first support frame  123  and a second support frame  124  positioned at both ends of the support frame  125 . First and second support blocks  121  and  122  are respectively installed at an end portion of the first and second support frames  123  and  124 . LM guides  126  are installed at end portions of the first and second support blocks  121  and  122 .  
         [0027]    A sensor unit  170  for sensing a position and distance of the tray plate  450  is formed at one side portion of the first support frame  123 . The driving unit  130  for moving the nozzle support unit  110  is formed at the other side portion of the first support frame  123 . A driving shaft  134  is connected to a motor  139  of the driving unit  130 . A first belt  133  is wound around and positioned on a driving pulley  131  installed on the driving shaft  134 , and an idle pulley  132  is installed on a first roller shaft  135 .  
         [0028]    A first roller  138  is connected to a portion of the first roller shaft  135 , and a second roller (not shown) is connected to a portion of a second roller shaft  136 . A second belt  137  is wound around first and second rollers. The first roller shaft  135  is inserted into the first support block  121  and the first roller  138 . The second roller shaft  136  is inserted into the second roller, and the second roller shaft  136  supported by the second support block  122 . The second support block  122  is formed at one end portion of the second support frame  124 .  
         [0029]    A vacuum generator  160  is installed on the second support frame  124 . The vacuum generator is operatively connected to a manifold  112  formed at one side portion of the nozzle support unit  110 . The guide block  150  is installed on the second belt  137 , and performs a guiding operation with the head block  140  formed at the lower portion of the guide block  150 . A guide groove  142  is formed at one side portion of the head block  140 , so that the LM guide  126  can be inserted into the guide groove  142 .  
         [0030]    The nozzle support unit  110  is formed at the lower end portion of the head block  140 . A plurality of nozzles  111  are supported in the nozzle support unit  110 . A plurality of vacuum pads  111   a  for sucking one side portion of the tray plate  450 , and a plurality of stoppers  111   b  for precisely and stably supporting and positioning a side portion of the tray plate  450  as it is sucked by the plurality of vacuum pads  111   a  are alternately formed on the plurality of nozzles  111 , as shown in FIGS. 5 and 6. The manifold  112  is formed on the nozzle support unit  110 , and transmits the vacuum force generated by the vacuum generator  160  to the plurality of vacuum pads  111   a  formed along a lower portion of the nozzle support unit  110 . The vacuum generator  160  and the manifold  112  are connected through a hose (not shown) which allows the vacuum force generated by the vacuum generator  160  to be distributed to the plurality of vacuum pads  111   a.    
         [0031]    The operation of the exchanger for the tray feeder in accordance with the present invention will now be explained.  
         [0032]    When the tray plate  450  transferred from the electronic parts feeder is received in the magazine  300 , and the driving motor  215  installed at one side portion of the cover frame  210  of the tray feeder stacker  200  is driven, the elevator  240  is lifted along the LM guide  218  by rotation of the ball screw  216  connected to a driving shaft (not shown) of the motor  215 . When the elevator  240  is lifted and stops at a predetermined position, the exchanger  100  is operated to retrieve a tray plate  450  from the magazine  300 .  
         [0033]    When the motor  139  of the driving unit  130  provided at one side portion of the guide support unit  120  of the exchanger  100  is driven and the driving shaft  134  connected to the motor  139  is rotated, the driving pulley  131  connected to the driving shaft  134  is rotated. The first belt  133  positioned in the driving pulley  131  is rotated, and the idle pulley  132  is rotated. The idle pulley  132  rotates the first roller shaft  135 , which is inserted into the first roller  138 . When the first roller  138  is rotated by the first roller shaft  135 , the second belt  137  is rotated along the outer surfaces of the first and second rollers.  
         [0034]    Because the guide block  150  is fixed on the second belt  137 , the guide block  150  is moved in a forward direction along with the second belt  137 , and the head block  140  and the nozzle support unit  110  connected to the guide block  150  are also moved in a forward direction. The manifold  112  formed on the nozzle support unit  110  receives the vacuum force generated by the vacuum generator  160  and distributes the vacuum force to the plurality of vacuum pads  111   a . Thus, the plurality of vacuum pads  111   a  uses the vacuum force to suck and grasp support protrusions formed at one side portion of the tray plate  450 .  
         [0035]    When the driving pulley  131  is inversely rotated by inverse-driving of the motor  139  of the driving unit  130 , the driving pulley  131  is inversely rotated, and the first belt  133  is rotated along the outer surfaces of the driving pulley  131  and the idle pulley  132 , thereby inversely rotating the idle pulley  132 .  
         [0036]    When the first roller shaft  135  is inversely rotated, the first roller  138  inserted into the other end portion of the first roller shaft  135  is also inversely rotated, and thus the second belt  137  is inversely rotated along the outer surfaces of the first and second rollers. The inverse rotation of the second belt  137  moves the guide block  150  away from the magazine  300  towards a rear portion. The nozzle support unit  110 , which is attached to the guide block  150  through the head block  140 , also moves away from the magazine  300 , while grasping the tray plate  450 , thus extracting the tray plate  450  from the magazine  300 .  
         [0037]    When the suction force of the vacuum pads  111   a  is removed by the operation of the vacuum generator  160 , the retrieved tray plate  450  is positioned on the second plate  440  positioned at the upper portion of the side of the transfer  400 . The tray plate  450  is transferred to a mounter by the second plate  440  by driving of the transfer  400 . At the same time, the first plate  430  positioned at the other side portion of the transfer  400  is returned to the exchanger side.  
         [0038]    When the mounting operation is complete, the tray plate  450  is mounted on the first plate  430 . A distance and position of the tray plate  450  are sensed by the sensor unit  170  provided at one side portion of the guide support unit  120 . When the tray plate  450  stops at a predetermined position, the nozzle support unit  110  formed at one side portion of the exchanger  100  is operated to grasp the tray plate  450 .  
         [0039]    The tray plate  450  is received in the magazine  300 , and then lowered with the magazine  300  by driving of the elevator  240 , and electronic parts are loaded on the tray plate  450 . Then, the tray plate  450  is received in the magazine  300  once again, and lifted with the magazine  300  to transfer the electronic parts to the mounter.  
         [0040]    In accordance with the present invention, when the tray plate  450  on which the electronic parts are mounted is transferred, the sensor unit  170  provided at one side portion of the guide support unit  120  senses the position of the tray plate  450 . In this manner, the tray plate  450  on which the tray  460  receiving the electronic parts is mounted can be stably and precisely positioned, held, moved, and released. More specifically, precise control of the vacuum force generated by the vacuum generator  160  and distributed to the plurality of vacuum pads  111   a  by the manifold  112  allows the nozzle support unit to firmly and precisely grasp, hold, and release the tray plate  450  as necessary. Additionally, the stoppers  111   b  provide for stable and precise positioning, movement, and release of the tray plate  450  by providing support to the side of the tray plate  450  so as to fix the tray plate  450  in place, stabilize the tray plate  450 , and inhibit movement of the tray plate  450  beyond the plane of the stoppers  111   b  while the tray plate is held by the vacuum pads  111   a.    
         [0041]    As discussed earlier, in accordance with the present invention, the tray plate on which the electronic parts is mounted is firmly, stably, and precisely grasped by the operation of the tray feeder exchanger, and stably transferred to a predetermined position through the action of the vacuum pads and the stoppers, which results in improved workability, reliability and productivity.  
         [0042]    As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiment is not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalences of such metes and bounds are therefore intended to be embraced by the appended claims.  
         [0043]    The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.