Patent Publication Number: US-6905353-B2

Title: Electrical connector assembly with pick up cap protecting contacts

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electrical connector assembly, and particularly to a combined pick up cap and electrical connector in which the pick up cap is attached onto the electrical connector. 
   2. Description of the Prior Art 
   On many production lines, electronic components such as electrical connectors are accurately positioned on a printed circuit board (PCB) such as a motherboard by means of a vacuum suction device. Since an electrical connector typically has a multiplicity of through holes in a top portion thereof, a pick up cap has to be pre-attached on the electrical connector. The vacuum suction device is then able to engage on a flat top surface of the pick up cap, in order to reliably move and accurately position the electrical connector onto the PCB. This kind of pick up cap is shown in U.S. Pat. No. 6,413,111 to Pickles et al., dated Apr. 6, 1993. 
   Commonly, a Land Grid Array (LGA) socket comprises a housing mounted on a printed circuit board, a metal clip pivotably engaged on the housing, and a plurality of contacts secured in the housing. The metal clip has a window in the center. Each contact protrudes a predetermined height above a surface of the housing to contact with a Land Grid Package (LGP), and the exposed portions of the contacts are liable to be distorted or even damaged when they are impacted by a foreign object. 
   On a production line, the metal clip of the conventional LGA socket is rotated downwardly to a horizontal closed position. A pick up cap is then attached on the metal clip. The pick up cap provides a smooth top surface for a vacuum suction device to engage. Thus the electrical connector can be moved and accurately positioned onto a predetermined location of the PCB. 
   However, one problem with this type of pick up cap is that it is attached on the clip is relatively far from the exposed portions of the contacts. Foreign matter, such as wires used on the assembly line or a finger of an operator, is liable to enter a space between the metal clip and the housing. The exposed portions of the contacts are liable to be damaged and/or contaminated by such foreign matter. 
   In view of the above, a new electrical connector assembly with a pick up cap which overcomes the above-mentioned disadvantages is desired. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide an electrical connector assembly having a pick up cap for providing a smooth top surface for a vacuum suction device, and for protecting contacts of an electrical connector of the electrical connector assembly. 
   To achieve the above-mentioned object, an electrical connector assembly in accordance with a preferred embodiment of the present invention comprises an electrical connector and a pick up cap attached onto the connector to provide a flat top surface for a vacuum suction device. The connector comprises a generally square insulative housing, a clip pivotally engaged to the housing, and a plurality of electrical contacts received in the housing. The housing comprises a front side, a rear side opposite to the front side, and a pair of opposite lateral sides interconnecting the front side and the rear side. The front side, rear side and lateral sides cooperatively define a cavity for receiving a central processing unit (CPU) therein. A bottom position of the housing under the cavity defines a multiplicity of passageways, the passageways receiving the contacts therein. A securing recess is defined in a middle portion of the front side, and a pair of spaced rear steps is defined in the rear side of the housing. A pair of spaced, rectangular lateral steps is formed in each lateral side of the housing. 
   The pick up cap comprises a planar body with a smooth top surface and a bottom surface thereof. The planar body comprises a head portion thereof corresponding to the securing recess of the housing, a pair of spaced tail portions at a rear edge thereof corresponding to the rear steps of the housing, and a pair of spaced lateral portions at each of opposite lateral sides thereof corresponding to respective lateral steps of the housing. A pair of spaced, parallel latch arms depends from a bottom surface of the head portion. In use, the pick up cap is mounted between the clip and the housing, therefore, it is close to the contacts and covers nearly all the exposed contacts, thereby providing effective protection for the contacts. 
   Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a simplified, isometric view of an electrical connector of the electrical connector assembly in accordance with the preferred embodiment of the present invention; 
       FIG. 2  is a simplified, exploded isometric view of a housing of the electrical connector of  FIG. 1 and a  pick up cap of the electrical connector assembly in accordance with the preferred embodiment of the present invention; 
       FIG. 3  is an assembled view of  FIG. 2 ; 
       FIG. 4  is an isometric view of the electrical connector assembly in accordance with the preferred embodiment of the present invention, showing a metal clip thereof in an open position; and 
       FIG. 5  is similar to  FIG. 4 , but showing the metal clip in a closed position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION 
   Reference will now be made to the drawings to describe the present invention in detail. 
   Referring to  FIGS. 1-2 , an electrical connector assembly of the present invention comprises an electrical connector  2  and a pick up cap  1 . The electrical connector  2  comprises an insulative housing  21  grasped by a reinforcement metal frame (not labeled), a clip  24  pivotally attached to the housing  21 , and a load lever  25  for pressing the clip  24  onto the housing  21 . A plurality of contacts  23  is secured in the housing  21 . The pick up cap  1  is attached onto the housing  21  to provide a flat top surface for the connector assembly, and to protect the contacts  23  of the electrical connector  2 . The clip  24  defines a center window  242 , and comprises two ribs  243  having two pressing portions  2431  respectively. 
   The housing  21  has a generally square configuration, and a plurality of electrical contacts  23  received therein. The housing  21  comprises a front side  211 , a rear side  212  opposite to the front side  211 , and a pair of opposite lateral sides  213  interconnecting the front side  211  and the rear side  212 . The front side  211 , rear side  212  and lateral sides  213  cooperatively define a generally rectangular cavity  210  therebetween for receiving a central processing unit (CPU) (not shown) therein. A bottom portion of the housing  21  under the cavity  210  defines a multiplicity of passageways  2101 , the passageways  2101  receiving the contacts  23  therein. Each contact  23  protrudes a predetermined height A above said bottom portion of the housing  21 , for contacting the CPU. 
   A securing recess  215  is defined in a middle portion of the front side  211  of the housing  21 . A pair of engaging bars  216  extends forwardly from the front side  211  at opposite ends of the securing recess  215  respectively. Each engaging bar  216  comprises an inside first engaging surface  2160 . A second engaging surface  2161  is defined on the front side  211  between the first engaging surfaces  2160 . 
   A pair of spaced rear steps  214  is formed in the rear side  212  of the housing  21 . A pair of spaced lateral steps  217  is formed in each lateral side  213  of the housing  21 , adjacent the cavity  210 . The securing recess  215 , rear steps  214 , and lateral steps  217  all define respective top surfaces, and the top surfaces being a same height B above said bottom portion of the housing  21 . In the preferred embodiment of the invention, height B is slightly greater than height A. 
   The pick up cap  1  has a planar body  10  having a smooth top surface  100 . The planar body  10  comprises a head portion  101  at a front thereof corresponding to the securing recess  215  of the housing  21 , a pair of spaced tail portions  102  at a rear edge thereof corresponding to the rear steps  214  of the housing  21 , and a pair of spaced lateral portions  103  at each of opposite lateral sides thereof corresponding to respective lateral steps  217  of the housing  21 . A pair of spaced, parallel latch arms  1012  depends from a bottom of the head portion  101 . Each latch arm  1012  comprises a main inner surface  1013  and an outer side edge  1014 , corresponding to the second engaging surface  2161  and a respective first engaging surface  2160  of the housing  21 , respectively. 
   Referring also to  FIGS. 3-4 , in assembly, the clip  24  is rotated to a vertical open position. The pick up cap  1  is placed on the housing  21 , and pressed downwardly. The tail portions  102  of the pick up cap  1  are supported on the rear steps  214  of the rear side  212 , and the inner surfaces  1013  of the latch arms  1012  loosely contact a top edge portion of the second engaging surface  2161 . 
   A front of the pick up cap  1  is pressed downwardly, and the latch arms  1012  deflect outwardly as they ride over said top edge portion. The bottom of the head portion  101  is attached on a top surface of the front side  211  in the securing recess  215 , with the lateral portions  103  fittingly attached on the corresponding lateral steps  217 , and the tail portions  102  fittingly attached on the corresponding rear steps  220 . That is, the pick up cap  1  is supported by top surfaces of the housing  21  in the securing recesses  215 , the rear steps  220 , and the lateral steps  217 . The inner surfaces  1013  of the latch arms  1012  resiliently abut against the second engaging surface  2161 . The side edges  1014  of the latch arms  1012  fittingly abut the first engaging surfaces  2160 . Thus, the pick up cap  1  is securely fastened on the connector  2 . Because the distance B is greater than the distance A, the pick up cap  1  does not contact or press the exposed contacts  23 . Rather, the pick up cap  1  protects the contacts  23  from being damaged or contaminated. 
   In use, the clip  24  is rotated to a horizontal closed position, and is fastened to the housing  21  by the load lever  25 . The top surface of the pick up cap  1  faces the center window  242  of the clip  24 . A vacuum suction device can pass through the center window  242  and engage on the top surface  100  of the pick up cap  1 , for moving of the connector assembly to a desired location. 
   As shown in  FIG. 5 , the pick up cap  1  is disposed between the housing  21  and the clip  24 . The pick up cap  1  is close to the exposed contacts  23 , thereby providing effective protection for the contacts  23 . 
   While a preferred embodiment in accordance with the present invention has been shown and described, equivalent modifications and changes known to persons skilled in the art according to the spirit of the present invention are considered within the scope of the present invention as defined in the appended claims.