Abstract:
A vibrator module adapted for use in a taper apparatus for advancing carrier tape having a plurality of compartments and for placing parts in the compartments. The vibrator module includes a motor that includes an output shaft that rotates in response to operation of the motor. The vibrator module also includes an eccentric weight mounted to and rotatable with the output shaft. The eccentric weight causes the motor to vibrate in response to rotation of the output shaft and eccentric weight. The vibrator module further includes a vibration transferring member interconnected with the motor and operable to transfer vibrations from the motor to the carrier tape to cause the parts to settle into the bottoms of the compartments.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is a continuation of co-pending U.S. patent application Ser. No. 10/050,900, filed Jan. 16, 2002, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/261,945, filed Jan. 16, 2001, the specifications of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a vibrator module for vibrating a carrier tape used to package electronic parts.  
       BACKGROUND  
       [0003]     It is known to package electronic computer chips, microprocessors, and the like (herein referred to generically as “parts”) in the compartments of a carrier tape and to wind the carrier tape on a reel for shipping. Typically, the parts are inspected immediately before being placed in the compartments of the carrier tape and are in some cases inspected after they are positioned within the compartments of the carrier tape.  
       SUMMARY  
       [0004]     While a part is in a compartment of the carrier tape, an overhead camera is often used to inspect the leads of the part. If the part is not positioned properly within the compartment, there may be false rejections of good parts. Thus, it is important to properly position the parts within the compartments of the carrier tape to reduce as much as possible the incidence of false rejections.  
         [0005]     The present invention achieves the goal of properly positioning the parts in the carrier tape compartments by positioning a vibrator module near the carrier tape compartments. Before a part is inspected in a compartment, the vibrator module is turned on and transfers vibration to the carrier tape. The vibrations cause the part to settle into the proper position within the compartment. If the part is rejected by the in-tape inspection camera, a second vibrator module may be used to again vibrate the tape. The part may then be re-inspected to determine whether the first rejection was a false one.  
         [0006]     The vibrator module preferably includes a small electric motor having an eccentric weight mounted on its output shaft. A vibration transferring member is interconnected with the electric motor, and extends to a position near the carrier tape. The motor vibrates as the output shaft rotates, and the vibration is transferred through the vibration transferring member to the carrier tape, thereby causing the part to properly settle in the tape compartment.  
         [0007]     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a side view of a taper apparatus embodying the present invention.  
         [0009]      FIG. 2  is a top view of the taper apparatus of  FIG. 1 .  
         [0010]      FIG. 3  is a schematic side cross-section view of a carrier tape in the taper apparatus.  
         [0011]      FIG. 4  is an enlarged view of a portion of  FIG. 2 , illustrating a vibrator module for use in the taper apparatus.  
         [0012]      FIG. 5  is a sectional view along line  5 - 5  of  FIG. 4 .  
         [0013]      FIG. 6  is a sectional view along line  6 - 6  of  FIG. 4 .  
         [0014]      FIG. 7  is a partially broken away schematic side view of an alternate construction of the vibrator module.  
         [0015]      FIG. 8  is a partial cross section view along line  8 - 8  of  FIG. 7 . 
     
    
       [0016]     Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The use of “consisting of” and variations thereof herein is meant to encompass only the items listed thereafter. The use of letters to identify elements of a method or process is simply for identification and is not meant to indicate that the elements should be performed in a particular order.  
       DETAILED DESCRIPTION  
       [0017]      FIGS. 1 and 2  illustrate a taper machine or taper apparatus  10  including a drive assembly  14  for advancing a carrier tape  18  through the taper apparatus  10 . The apparatus  10  also includes a control panel  22  and the appropriate electronic control system for controlling the drive assembly  14  and other components of the apparatus  10 . The apparatus  10  also includes a pair of guide rails or members  26  that guide the carrier tape  18  along the apparatus  10 .  
         [0018]     As seen in  FIG. 3 , the carrier tape  18  includes a top portion  30  and a plurality of compartments or pockets  34  recessed with respect to the top portion  30 . The carrier tape  18  also has two flanges  36  ( FIG. 6 ) that may extend over the top of the guide members  26  of the taper apparatus  10  such that the compartments  34  extend down between the guide members  26 . The compartments  34  include tapered or angled side walls  38  and flat bottoms  42 , and are thus designed to guide parts  46  into a relatively horizontal or flat orientation at the bottom of the compartments  34 . The taper apparatus  10  includes a pick-and-place head  50  having a vacuum nozzle  54 . The pick-and-place head  50  moves up and down to position one part  46  in each compartment  34 . The tape  18  is then advanced along the taper apparatus  10 , and a clear cover tape  55  is sealed to the flanges  36  with a sealing shoe  56 . The parts  46  are then examined in-tape through the cover tape  55  with a robotic vision system including a camera  58 . Alternatively, the camera  58  may be positioned to inspect the parts  46  prior to the cover tape  55  being applied. The robotic vision system is used to inspect leads  62  and other aspects of the parts  46 .  
         [0019]     In some existing taper machines, false rejections are made by the robotic vision system when the parts are canted or tilted, or are otherwise not settled properly within the compartments. Such misalignment may occur when, for example, the pick-and-place head is not positioned directly above the tape compartment, the part is not centered on the pick-and-place head, or the part is not cleanly dropped into the compartment by the pick-and-place head. Misaligned parts may appear to have leads that are too long or too short to pass inspection, even though the leads are in fact of the proper length. For example, if the part is not settled, the camera  58  may see a partial reflection of the part off of the side walls  38  that distorts the true length of the leads  62 .  
         [0020]     Referring to  FIGS. 4-6 , the apparatus  10  includes two vibrator modules  66 , each including a small electric motor  70  having an output shaft  72 , an eccentric weight  74  mounted to the output shaft  72 , and a finger or a vibration transferring member which in the illustrated embodiment is a thin flexible strip of metal  78 . The flexible strip  78  is attached in a cantilevered fashion at one end to a mounting boss  82  by a fastener  84  and projects away from the mounting boss  82 . The mounting boss  82  is mounted to the taper apparatus  10  or one of the guide members  26  by fasteners  85 . The motor  70  is mounted to the flexible strip  78  with bent fingers  86  (as illustrated in  FIG. 5 ), fasteners, solder, brazing, welding, or any other suitable attachment means. The motor  70  is therefore supported in cantilevered fashion by the flexible strip  78 . The flexible strip  78  is bent around the eccentric weight  74  and has a portion  90  positioned in a window  92  in one of the guide members  26 . The portion  90  is thus directly alongside the compartment  34  that is currently under the pick-and-place head  50  or camera  58 . Alternatively, the vibrations could be passed through the guide member  26 , and the window  92  would not be needed.  
         [0021]     In operation the first vibrator module  66  is positioned next to the carrier tape  18  under the pick-and-place head  50 , and the second vibrator module  66  is positioned next to the carrier tape  18  under the camera  58  as seen in  FIGS. 1 and 2 . Each time a part  46  is positioned in a compartment  34  by the pick-and-place head  50 , the control system actuates the electric motor  70  of the first vibrator module  66 . The rotating eccentric weight  74  creates vibrations which are passed by the flexible strip  78  to the compartment  34  currently under the pick-and-place head  50 . If the part  46  is not properly positioned (i.e., in a flat orientation at the bottom of the compartment  34 ), the vibrations cause the part  46  to settle into a relatively flat orientation at the bottom  42  of the compartment  34  prior to inspection by the robotic vision system. If the part  46  is out of the compartment  34 , the vibrations help to move the part  46  into the compartment  34 . If the part  46  is properly positioned in the compartment  34 , the part  46  will remain in the relatively flat orientation at the bottom of the compartment  34  during such vibration.  
         [0022]     When the robotic vision system detects a defective part  46 , a reject signal is sent to the controller. The controller then activates the second vibrator module  66  to vibrate the carrier tape  18  and compartment  34  under the camera  58 . The part  46  is then re-inspected to see if the rejection was a false rejection due to the part  46  not being properly settled within the compartment  34 . An operator of the apparatus  10  may program the control system with the number of re-inspections that should be performed before the part  46  is finally determined to be a bad part  46 . The control system actuates the motor  70  before each re-inspection.  
         [0023]     It is preferable to adjust the speed of the motor  70  to adjust the amplitude and frequency of vibration produced to a suitable level for the tape  18  and parts  46  involved. The speed may be adjusted by regulating the amount of voltage entering the motor  70 . A large voltage entering the motor  70  actuates the motor  70  at a high speed and produces large vibrations, while a small voltage entering the motor  70  actuates the motor at a low speed and produces small vibrations. Lower voltage and small vibrations are used for small compartments  34  and small parts  46 , while high voltage and large vibrations are used for large compartments  34  and large parts  46 .  
         [0024]     When at rest, the flexible strip  78  preferably does not contact the adjacent compartment  34 , but is very close to it. In operation, the flexible strip  78  bumps into the compartment  34  as the strip  78  vibrates, and thereby transfers the vibrations to the compartment  34 . Alternatively, the flexible strip  78  may be in contact with the adjacent compartment  34  while at rest.  
         [0025]     It should be noted that the taper apparatus  10  may employ only one of the first and second vibrator modules  66  described above, and that use of even one of the vibrator modules  66  would still decrease the incidence of false rejections by the in-tape robotic vision system or station. Also, the second vibrator module  66  may be positioned upstream of the camera  58  if a second robotic vision station is used in the taper apparatus  10 , provided the second vibrator module  66  vibrates the tape prior to the second inspection in the event of a rejection by the first robotic vision station.  
         [0026]     It should further be noted that the vibrator module may be used in a machine other than the illustrated taper machine.  
         [0027]     Referring to  FIGS. 7 and 8 , an alternative embodiment of the present invention is illustrated. Some components are similar to the construction described above, and like components are given like reference numbers. A vibrator module  94  includes a motor  98 , an output shaft  102 , an eccentric weight  106  and a vibration transferring member  110 . The motor  98  is mounted to the taper apparatus  10  or the guide member  26  on a resilient mounting structure  114  (e.g., springs, rubber, etc.). An adjustable damper  118  is used to vary the amount of vibration caused by operation of the motor. The vibration transferring member  110  is mounted to the motor  98  and is used to transfer the vibration to the carrier tape  18 .  
         [0028]     Although particular constructions of the present invention have been shown and described, other alternative constructions will be apparent to those skilled in the art and are within the intended scope of the present invention. For example, the vibrator module  66  may include vibration sources other than the illustrated motors  70 ,  98  and eccentric weights  74 ,  106 , such as piezoelectric material operating under the influence of pulse current, a relay switch operating at a selected frequency, a voice coil operating at a selected frequency, or other suitable vibration sources. Thus, the present invention is to be limited only by the following claims.