Patent Publication Number: US-2006000084-A1

Title: Nozzle of surface mount device

Description:
BACKGROUND OF THE INVENTION  
      (a) Field of the Invention  
      The present invention relates to a component of a surface mount device and, more particularly, to a nozzle of a module-packing system for use in a multi-function chip-mounting device.  
      (b) Description of the Related Art  
      During a packing procedure, a sucking type nozzle is used for taking up and putting down electronic components. Referring to  FIG. 1 , a conventional nozzle  100  includes a shaft  110 , a positioning bar  120  and an elastomer  130 . The shaft  110  axially defines a passage  111 . The positioning bar  120  is made of metal. In an upper end, the positioning bar  120  includes a seat  121  fit around the shaft  110 . In a lower end, the positioning bar  120  defines a chamber  123  of an enlarged diameter. The elastomer  130  is put in the chamber  123  and extends from the lower end of the positioning bar  120  by a proper distance. The elastomer  130  centrally defines a passage  131  communicated with the passage  111  of the shaft  110 .  
      When the nozzle  100  sucks an IC chip  400 , the elastomer  130  contacts the IC chip  400 . When the passages  111  and  131  start to suck, the elastomer  130  becomes a sucking surface and sucks the IC chip  400 .  
      Although the nozzle  100  can suck the IC chip  400 , the external size of the positioning bar  120  is designed so that it is generally suitable only for IC chips  400  of a size. This is because the elastomer  130  is compressed and deformed when it contacts the IC chips  400 , and the lower end  124  of the positioning bar  120  contacts the IC chips  400  in order to ensure that the IC chips  400  are positioned horizontally. The IC chips  400  are often different from one another in size so that a printed circuit board requires several nozzles  100  of different sizes. As shown, the surface mount device generally includes six replacement seats for receiving six nozzles  100  of different sizes. A round of replacing a nozzle  100  takes about three seconds. A program design generally requires three to four rounds of replacement, taking about 1/15 of total time. Hence, a high frequency of replacement affects throughput. Moreover, because the positioning bar  120  is made of hard metal, the thickness of the wall of the chamber in the lower end  124  of the positioning bar  120  is generally thick. The contact surface with an IC chip  400  is small. Hence, the friction is small. When the IC chip  400  is sucked and moved, inertia against the start and stop is weak. Hence, the electronic component can easily be aligned poorly and even dropped, thus affecting the packing procedure.  
      The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.  
     SUMMARY OF THE INVENTION  
      It is an objective of the present invention to provide a nozzle of surface mount device including a shaft and a sleeve suitable for electronic components of different sizes, thus reducing the frequency in replacement of nozzles in a packing procedure.  
      It is another objective of the present invention to provide a nozzle of surface mount device including a shaft and a sleeve for increasing friction with electronic components in order to increase the stability in positioning the electronic components and reducing suck impact on the electronic components, thus avoiding scratching and damaging the electronic components.  
      To achieve the above-mentioned objectives, the present invention provides a nozzle of surface mount device. The nozzle includes a shaft and a sleeve. The shaft defines a passage at an end and at least one passage at an opposite end. The passages are communicated for communicating air. The sleeve includes a seat for engagement with the shaft and an enlarged opening at an opposite end. The enlarged opening and the external diameter of the sleeve form a sucking surface. The sleeve provides an increased sucking surface for electronic components. While sucking electronic components, the sleeve, that includes the increased sucking surface, is suitable for electronic components of different sizes. Moreover, the sleeve includes increased sucking surface friction and elasticity, and is fit around the shaft. While sucking electronic components, the sleeve, that includes the increased contact surface friction, provides a better sucking force, and increases the stability in positioning. Moreover, the sleeve, that is elastic, can reduce sucking impact on electronic components.  
      Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description referring to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention will be described via detailed illustration of the preferred embodiment referring to the drawings.  
       FIG. 1  is a perspective view of a conventional nozzle of a surface mount device.  
       FIG. 2  is an exploded view of a nozzle of a surface mount device according to the preferred embodiment of the present invention.  
       FIG. 3  is the relation of a sleeve of the nozzle of  FIG. 2  with IC chips of different sizes. 
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION  
      Referring to  FIG. 2 , according to the preferred embodiment of the present invention, a nozzle  200  includes a shaft  210  and a sleeve  220 . The shaft  210  defines a passage  211  and a recess  212 . The sleeve  220  is made of rubber. The sleeve  220  includes a seat  221  and a protrusion  222  at an end. The seat  221  is engaged with the shaft  210 . The protrusion  222  corresponds to the recess  212  of the shaft  210 . When the seat  221  is engaged with the shaft  210 , the protrusion  222  is fit in the recess  212  for positioning. The sleeve  220  defines a passage  223  at an opposite end. The passage  223  is communicated with the passage  211  of the shaft  210 . The passage  223  of the sleeve  220  becomes an enlarged opening  224  at a lower end. The enlarged opening  224  and an external diameter  225  of the sleeve form a sucking surface  226 . The sleeve  220  must be fit around the shaft  210  so that the nozzle  200  includes a sucking surface  226 . When the passages  211  and  223  suck, the sucking surface  226  provides adequate friction for sucking the IC chip  400 . When the passages  211  and  223  expel, the sucking is terminated and the IC chip  400  is released.  
      The advantage of the present invention is ability to suck IC chips  400  of different sizes. Referring to  FIG. 3 , the enlarged opening  224  of the sleeve  220  and the external diameter  225  define the range of the sucking surface  226 . As long as an IC chip  400  is covered by the enlarged opening  224 , effective sucking is possible. According to our experiments, the sleeve  220  can effectively suck IC chips  400  of different sizes. When the enlarged opening  224  of the sleeve  220  is ψ7 and the external diameter  225  is ψ11, the nozzle  200  can substitute for positioning bars  120  with external diameters of ψ7 to ψ15.  
      As discussed above, the present invention is not limited to the sizes of the IC chips  400 . The nozzle  200  of a size is suitable for the IC chips  400  of similar diameters. That is, a nozzle  200  of a size substitutes for a plurality of conventional nozzles  100 . Thus, stock of parts can be reduced effectively in order to reduce the production cost. In addition, because of the special design of the contact surface of the nozzle  200 , stability in movement of the IC chips  400  is improved. The sleeve  220  is made of rubber to avoid damaging the IC chips  400 . As mentioned, the effect of present invention is better than that of the conventional nozzle  100 .  
      The present invention has been described via detailed illustration of the preferred embodiment. Those skilled in the art can derive variations from the preferred embodiment without departing from the scope of the present invention. Therefore, the preferred embodiment shall not limit the scope of the present invention defined in the claims.