Abstract:
A testing apparatus is provided to test whether a distance between a first and a second portions of an object is eligible. The testing apparatus includes a worktable, a positioning mechanism to support the object, a pressing mechanism to secure the object, and an actuating mechanism. The actuating mechanism outputs signals to reflect the relative position of the correspond to-be-tested portion and the actuating mechanism, therefore a controlling device indicates whether the distance between the to-be-tested portion and the base plane is eligible or not according the outputting signals of the corresponding actuating mechanism.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to testing apparatuses and, more particularly, to a testing apparatus to test whether distances between to-be-tested portions and a reference plane are eligible or not. 
     2. Description of the Related Art 
     Measuring distances between to-be-tested portions and a base plane is almost always necessary in manufacturing. Referring to  FIGS. 1 and 2 , a heat dissipating device for a central processing unit (CPU) includes a heat-conductive block  100  made of copper, a fin assembly  200  made of aluminum, and a supporting bracket  300 . A flange  102  is formed at an end of the heat-conductive block  100 . The supporting bracket  300  includes a flat mounting portion  301  and four bended fixing legs  302  extending from the mounting portion  301 . A mounting hole  3011  is defined in a middle area of the mounting portion  301 . A receiving passage  201  is defined in the fin assembly  200 . In assembly, the heat-conductive block  100  is passed through the mounting hole  3011  of the mounting portion  301  of the supporting bracket  300  and the receiving passage  201  of the fin assembly  200 , therefore, the mounting portion  301  is sandwiched between the flange  102  of the heat-conductive block  100  and a bottom of the fin assembly  200 . To mount the heat dissipating device to the CPU on a main board, the heat-conductive block  100  abuts against a top surface of the CPU, and the fixing legs  302  abut against and are fixed to the main board. A distance H between each of the fixing legs  302  and the mounting portion  301  should be eligible to ensure the heat-conductive  100  tightly contact the CPU. 
     In a conventional distance testing, the mounting bracket  300  is disposed on a testing tool, and an operator manually presses the mounting bracket  300  onto a testing platform. The distances H between each of the fixing legs  302  of the bracket  300  and the mounting portion  301  are measured using gauges by the operator. Thus, the accuracy and reliability of the testing result is affected. Furthermore, the conventional testing is inefficient and laborious. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded, isometric view of a heat dissipating device. 
         FIG. 2  a lateral view of an assembled heat dissipating device of  FIG. 1 . 
         FIG. 3  is an exploded, isometric view of an exemplary embodiment of a testing apparatus, the testing apparatus includes four actuating mechanisms. 
         FIG. 4  is an exploded, isometric view of one of the actuating mechanisms of  FIG. 3 . 
         FIG. 5  is an assembled, isometric view of the testing apparatus of  FIG. 3  and a supporting bracket, the supporting bracket includes a mounting portion and four fixing legs extending form the mounting portion. 
         FIG. 6  is a partial, cross-sectional view of  FIG. 5 , showing the distance between one of the fixing legs and the mounting portion of the supporting bracket is less than a minimum eligible value. 
         FIG. 7  is a partial, cross-sectional view of  FIG. 5 , showing the distance between one of the fixing legs and the mounting portion of the supporting bracket is larger than a maximum eligible value. 
         FIG. 8  is partial, cross-sectional view of  FIG. 5 , showing the distance between one of the fixing legs and the mounting portion of the supporting bracket is eligible. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 3 , in an exemplary embodiment, a testing apparatus is provided to test whether a distance between a to-be-tested portion and a reference plane is eligible. The testing apparatus includes a worktable  10 , a pressing mechanism  30 , a positioning mechanism  50 , four actuating mechanisms  70 , and an electrically controlling device  90 . 
     Referring to  FIG. 5 , in one embodiment, there are four to-be-tested portions, for instance, four fixing legs  302   a  of a supporting bracket  300   a  of an heat dissipating device. The supporting bracket  300   a  is made of electrically conductive material. The reference plane is defined by a bottom surface of the mounting portion  301   a  of the supporting bracket  300   a . A distance h is defined between each of the fixing legs  302   a  and the mounting portion  301   a.    
     The worktable  10  includes a base  11 , and a cover  12  made of insulated material. In one embodiment, the base  11  is a box with an opening defined on a top of the base  11  for receiving the cover  12 . The cover  12  includes a through hole  123  defined in a middle of the cover  12 , four positioning holes  121  around the through hole  123 , and two pairs of screw holes  122  located on two perpendicularly crossed lines around each of the positioning holes  121 . 
     The pressing mechanism  30  includes a fixing arm  31 , a pneumatic cylinder  33 , a securing member  35 , and a pressing member  37 . In one embodiment, the fixing arm  31  is L-shaped, and includes a supporting portion  313 , and a connecting portion  315  perpendicular to the supporting portion  313 . A coupler  3151  and a tab  3153  extend from a top edge and a bottom edge of a distal end of the connecting portion  315 , respectively. The coupler  3151  defines a semi-circular slot  3152  therein. The tab  3153  defines a through hole  3156  therein. The semi-circular slot  3152  and the through hole  3156  are substantially in alignment with a vertical line. The pneumatic cylinder  33  includes a cylindrical body  332 , and a plunger  334  retractably attached to the cylindrical body  332 . A threaded portion  3321  is formed at an end of the cylinder body  332  adjacent to the plunger  334 . A threaded portion  3341  is formed at a distal end of the plunger  334 . The pressing member  37  is cylindrical and defines a screw hole  372  along a central axis of the pressing member  37 . The securing member  35  defines a semi-circular slot in a side of the securing member  35 , corresponding to the slot  3152  of the coupler  3151 . 
     The positioning mechanism  50  includes an anvil  52  made of electrically conductive material, two pairs of position pins  54 , a photoelectrical switch  56 , and a terminal  58 . The anvil  52  is shaped like a stepped column, and defines a rectangular through hole  521  along a central axis thereof. 
     Referring to  FIG. 4 , the actuating mechanisms  70  are made of electrically conductive material. Each of the actuating mechanisms  70  includes a detecting pole  71 , a first resilient member  72 , a first abutting member  73 , a second abutting member  74 , a contacting member  75 , two second resilient members  76 , and two terminals  771 ,  781 . The detecting pole  71  includes a disk-shaped head  711  and a shank  713  extending from the head  711 . A screw hole (not shown) is defined in a distal end of the shank  713  opposite to the head  711 . In one embodiment, the resilient member  72  and the second resilient members  76  are coil springs. The first abutting member  73  includes an abutting bar  731  and a cylindrical guiding sleeve  733  perpendicularly extending from a middle of the abutting bar  731 . A guiding hole  735  is defined in the guiding sleeve  733  and extends through the abutting bar  731 . Two fixing holes  7311  are respectively defined in opposite ends of the abutting bar  731 . The second abutting member  74  is U-shaped, and includes a blocking portion  741  and two spaced fixing portions  743  extending from opposite ends of the block portion  741 . An inference-avoiding hole  7412  is defined in the blocking portion  741  between the fixing portions  743 . Each of the fixing portions  743  defines a fastening hole  7432  along a direction perpendicular to the block portion  741 . The contacting member  75  defines a center hole  751  therein. 
     The electrically controlling device  90  is attached to an inside of the base  11 , and includes a indicator  92 , four pairs of indicators  91 , and two buttons  93  exposed on an outside of the base  11 . The indicator  92  is configured to indicate whether all the distances h between the four fixing legs  302   a  and the mounting portion  301   a  of supporting bracket  300   a  are eligible. Each pair of the indicators  91  is configured to indicate whether the distance between each of the four fixing legs  302   a  and the mounting portion  301   a  of supporting bracket  300   a  is eligible. 
     Referring to  FIGS. 3-6 , to mount one of the actuating mechanisms  70  to the cover  12 , the first abutting member  73  is secured to a bottom of the cover  12 , with the guiding portion sleeve  733  of the first abutting member  73  extending through one of the positioning holes  121 , and two screws  801  respectively extending through the fixing holes  7311  of the abutting bar  731  to engage in a first pair of the screw holes  122  around the corresponding positioning hole  121  of the cover  12 . The terminal  771  is fixed around the shank of one of the screws  801  and sandwiched between the head of the corresponding screw  801  and the lower portion of the abutting bar  731 . The shank  713  of the detecting pole  71  is passed through the first resilient member  72 , the corresponding positioning hole  121  of the cover  12 , and the guiding hole  735  of the guiding sleeve  733  of the first abutting member  73 . Opposite ends of the first resilient member  72  resist against the abutting bar  731  and the head  711  of the detecting pole  71 . The contacting member  75  is secured around the shank  713  and a screw  802  is extended through the center hole  751  to engage in the screw hole of the shank  713 . The head  711  of the detecting pole  71  is urged upward by the first resilient member  72 , therefore, the contacting member  75  is capable of moving with the detecting pole  71  to abut against the abutting bar  731  of the first abutting member  73 . The second abutting member  74  is secured to the bottom of the cover  12 , with two bolts  803 . Each of the bolts  803  is passed respectively extending through two washers  804 , the second resilient members  76 , the fastening holes  7432  of the second abutting member  74  to engage in a second pair of the screw holes  122  around the corresponding positioning hole  121  of the cover  12 . The terminal  781  is fixed around the shank of one of the bolts  803  and sandwiched between the head of the corresponding bolt  803  and the corresponding washer  804 . In assembly, the second abutting member  74  is spaced from and bestrides across the first abutting member  73 . According to the similar process described above, the other three actuating mechanisms  70  are mounted to the cover  12 , corresponding to the positioning holes  121  of the cover  12 . Referring to  FIGS. 6-8 , a sliding range of the contacting member  75  between the abutting bar  731  of the first abutting member  73  and the blocking portion  741  of the second abutting member  74  is defined as w. The sliding range w is equal to a difference between a maximum and a minimum eligible value of the distance h. 
     Referring also to  FIG. 5 , to mount the positioning mechanism  50  to the cover  12 , the photoelectrical switch  56  is retained in the through hole  521  of the anvil  52 . The terminal  58  is fixed to a bottom of the anvil  52  with a screw  805 . The anvil  52  is secured to the top of the cover  12  and the photoelectrical switch  56  is aligned with the through hole  123  of the cover  12 . The two pairs of the position pins  54  are secured to the cover  12  adjacent to the anvil  52 . The fixing arm  31  is perpendicularly connected to the cover  12 . The cylinder body  332  of the pneumatic cylinder  33  is engaged in the slot  3152  of the coupler  3151  of the fixing arm  31 . The threaded portion  3321  of the cylinder body  332  and the plunger  334  of the pneumatic cylinder  33  are passed through the through hole  3156  of the tab  3153  of the fixing arm  31 . The securing member  35  is attached to the coupler  3151 , with a pair of conventional fasteners extending through the securing member  35  to engage in the coupler  3151 . The semi-circular slot of the securing member and the semi-circular slot  3152  of the coupler  3151  cooperatively define a space to receive the cylindrical body  332 . A nut  806  is engaged with the threaded portion  3321 . Thus, the pneumatic cylinder  33  is fixed to the fixing arm  31 , aligned with the photoelectrical switch  56 . The threaded portion  3341  of the plunger  334  engages in a nut  807  and the screw hole  372  of the pressing member  37  to attach the pressing member  37  to the plunger  334 . The nut  807  is manipulated to lock the pressing member  37  to the plunger  334 . The terminals  58 ,  771 ,  781  and the photoelectrical switch  56  are respectively connected to the controlling device  90  leads (not shown), therefore, the anvil  52 , the first abutting member  73 , the second abutting member  74 , and the photoelectrical switch  56  are electrically coupled to the electrically controlling device  90 . The cover  12  is attached to the base  10 , thereby shielding the opening of the base  11 . Distances between a top surface of the anvil  52  and the top surfaces of the heads  711  of the detecting poles  71  are equal to the distance h. 
     In testing, the mounting portion  301   a  of the supporting bracket  300   a  is disposed on the top surface of the anvil  52  and the fixing legs  302   a  of the supporting bracket  300   a  are aligned with the top surfaces of the detecting poles  71  of the actuating mechanisms  70 . Two opposite fixing legs  302   a  of the supporting bracket  300   a  are positioned by the two pairs of the positioning pins  54 , therefore, a rotation of the supporting bracket  300   a  is prevented. The buttons  93  are operated to drive the plunger  334  of the pneumatic cylinder  33  to extend downward until the pressing member  37  abuts against the mounting portion  301   a  to make the bottom surface of the mounting portion  301   a  to be coplanar with the top surface of the anvil  52 . At the same time, the photoelectrical switch  56  is shield to start the controlling device  90 . The anvil  52  is supplied a low voltage level, the first abutting member  73  and the second abutting member  74  are supplied high voltage levels, respectively. Since the supporting bracket  300   a  contacts with the anvil  52 , the supporting bracket  300   a  is also at a low voltage level. The distance “h” of each of the fixing legs  302   a  of the supporting bracket  300   a  and the mounting portion  301   a  can be indicated by the controlling device  90  as below detailed description. 
     Referring to  FIG. 6 , when the distance h of one of the fixing legs  302   a  of the supporting bracket  300   a  is less than a minimum eligible value, the fixing leg  302   a  keep spaced from the head  711  of the detecting pole  71  of the corresponding actuating mechanism  70 . Thus, the first abutting member  73  and the second abutting member  74  both remain at the high voltage levels. One of the corresponding pair of the indicating lights  91  may be lighted up to show the current distance h is ineligible, and less than the minimum eligible value. 
     Referring to  FIG. 7 , when the distance h of one of the fixing legs  302   a  of the supporting bracket  300   a  is larger than the maximum eligible value, the fixing leg  302   a  abuts against the head  711  of the detecting pole  71  of the corresponding actuating mechanism  70  to urge the detecting pole  71  to move toward the second abutting member  74 . The contacting member  75  moves with the detecting pole  71  to abut against the second abutting member  74 . The first abutting member  73 , the supporting bracket  300   a , and the second abutting member  75  are electrically connected. Therefore, the first abutting member  73  and the second abutting member  74  turn to low voltage levels. The other one of the corresponding pair of the indicating lights  91  may be lighted up to show the current distance h of the fixing leg  302   a  is ineligible, and larger than the maximum eligible value. The second resilient members  76  can be compressed to prevent the second abutting member  74  from being destroyed by excessive striking of the detecting poles  71 . 
     Referring to  FIG. 8 , when the distance h of one of the fixing legs  302   a  of the supporting bracket  300   a  is between the maximum value and the minimum eligible value, the fixing leg  302   a  abuts against the head  711  of the detecting pole  71  of the corresponding actuating mechanism  70  to urge the detecting pole  71  to move toward the second abutting member  74 , without contacting the second abutting member  74 . The first abutting member  73  is electrically connected to the supporting bracket  300   a  through the detecting pole  71 . Therefore, the first abutting member  73  turns to low voltage level and the second abutting member  74  still remains at the high voltage level. Neither of the corresponding pair of the indicating lights  91  may be lighted up to show the current distance h is eligible. 
     When the first abutting members  73  of the four actuating mechanisms  70  are at low voltage levels and the second abutting members  74  are at high voltage levels, the four pairs of indicators  93  are not be lighted up and the indicator  92  is lighted up to show the distances h of the four fixing legs  302   s  of the support bracket  300   a  are eligible. 
     It is believed that the present embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the description or sacrificing all of its material advantages, the example hereinbefore described merely being exemplary embodiment.