Patent Publication Number: US-6905373-B2

Title: Electrical contact for cable assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Relevant subject matter is disclosed in co-pending application entitled “CABLE ASSEMBLY HAVING POWER CONTACTS” which is invented by the same inventor as this patent application and assigned to the same assignee with this application. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a cable assembly, and particularly to a cable assembly having improved contacts for ensuring a reliable connection with complementary contacts. 
   2. Description of Related Art 
   Electrical connectors are widely used in electronic systems for establishing an electrical connection between two electronic devices thereof. Some electronic devices, such as servers, are equipped with power connectors for carrying power. These power connectors generally comprise two mating halves, i.e., a plug connector connecting with a circuit substrate and a receptacle cable assembly connecting with a power supply system for supplying power to the circuit substrate. The receptacle cable assembly generally comprises a unitarily molded insulating housing, a plurality of socket-type power contacts retained in the housing, and a plurality of cables terminated to corresponding power contacts. Such a socket-type power contact can be referred to U.S. Pat. No. 3,964,815. Once the socket-type contacts engage with corresponding pin-type contacts of the plug connector, a mechanical and electrical connection is established between the plug connector and the receptacle cable assembly. However, in some particular circumstances where high shock or vibration exists, the connection of the plug contact and the receptacle contact is easy to become loose. This results in an unreliable electrical connection between the plug connector and the receptacle cable assembly. 
   U.S. Pat. No. 5,102,354, issued to Crane et al., discloses a receptacle cable assembly having receptacle contacts to solve the above-mentioned problem. Each receptacle contact includes a front contact portion, a rear cable gripping portion and an intermediate portion interconnecting the contact portion with the gripping portion. The contact portion has a central contact beam extending upwardly and rearwardly from a front end of the intermediate portion to form a curved contact section above the intermediate portion, and a pair of side contact beams integrally and upwardly extending from two opposite sides of the central contact beam. When the receptacle cable assembly engages with a complementary plug connector, a plug contact of the complementary plug connector electrically contacts with the side contact beams and the curved contact section of the central contact beam to achieve multiple contact points therebetween. However, since the side contact beams integrally extend from the central contact beam, the side contact beams would move downward with the resiliently downward deformation of the central contact beam during the insertion of the plug contact, whereby a vertical wipe friction occurs between the plug contact and the side contact beams. After repeated insertion of the plug contact, the outside conductive material, such as gold, coated on the plug contact and the side contact beams of the receptacle contact may fall off, thereby adversely affecting the electrical connection between the plug contact and the receptacle contact. On the other hand, the side contact beams are easy to rotate with the deformation of the central contact beam, thereby increasing the difficulty of ensuring a reliable engagement between the plug contact and the receptacle contact. 
   Hence, an improved electrical contact for a cable assembly is required to overcome the disadvantages of the related art. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a cable assembly having improved electrical contacts for ensuring a reliable connection with a complementary contact. 
   In order to achieve the object set forth, a cable assembly in accordance with the present invention comprises an insulating housing defining a plurality of cavities, a plurality of contacts received in corresponding cavities of the housing and a plurality of cables terminated to the corresponding contacts. Each contact comprises an intermediate portion fixing the contact in the housing, a central contact beam extending upwardly from a front end of the intermediate portion, a pair of side contact beams extending upwardly from two opposite sides of the intermediate portion and a tail portion extending from a rear end of the intermediate portion. The side contact beams comprise a pair of vertical arms located at opposite sides of the central contact beam and a pair of resilient side arms extending rearwardly from the vertical arms. The side arms have connecting portions extending toward each other. 
   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. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an assembled perspective view of a cable assembly in accordance with the present invention; 
       FIG. 2  is a view similar to  FIG. 1  but taken from a different perspective; 
       FIG. 3  is an exploded view of the cable assembly shown in  FIG. 1 ; 
       FIG. 4  is an exploded view of the cable assembly shown in  FIG. 2 ; 
       FIG. 5  is an enlarged perspective view of an electrical contact used in the cable assembly; 
       FIG. 6  is a view similar to  FIG. 5  but taken from a different perspective; 
       FIGS. 7–10  are cross-sectional views taken from different sections of the cable assembly shown in  FIG. 1 ; 
       FIG. 11  is an enlarged view of a circled portion of  FIG. 8  indicated by reference number  11  thereof; and 
       FIG. 12  is an enlarged view of a circled portion of  FIG. 9  indicated by reference number  12  thereof. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Reference will now be made in detail to the preferred embodiment of the present invention. 
   Referring to  FIGS. 1–4 , a cable assembly  1  in accordance with the present invention comprises a receptacle connector  2  and a plurality of cables  3  electrically connecting with the receptacle connector  2 . Each cable  3  includes an inner conductive core  30  and an outer insulator  32  surrounding the inner conductive core  30 . The conductive core  30  is exposed outside at one end of the cable  3 . 
   The receptacle connector  2  includes a rectangular insulating housing  4  and a plurality of contacts  5  received in the housing  4 . The housing  4  has a front face  400  and an opposite rear face  402 . The housing  4  defines a plurality of cavities  40  extending through the front face  400  and the opposite rear face  402  along a lateral direction thereof and a corresponding number of slots  42  extending through the front face  400  while not extending through a bottom  403  ( FIG. 10 ) of the housing. The slots  42  communicate with corresponding cavities  40 . Each cavity  40  is further recessed outwardly from opposite inner sides  41  thereof to form a pair of slits  44 . A plurality of latching bosses  46  is formed on a top  404  of the housing  4  adapted to be received in a corresponding latching slot of a complementary connector (not shown). 
   Each one of the contacts  5  is identical in structure and an exemplary one thereof is shown in  FIGS. 5 and 6 . Each contact  5  is formed from a conductive material and includes a planar intermediate portion  50  having a front narrow section  501  and a rear wide section  503 , a central contact beam  52  extending integrally from a front end  500  of the narrow section  501 , a pair of side contact beams  54  extending integrally upwardly from two opposite sides  502  of the narrow section  501  adjacent to the front end  500  and a tail portion  56  extending rearwardly from a rear end of the wide section  503  to electrically connect with a corresponding cable  3 . The intermediate portion  50  has a tab  504  extending downwardly and rearwardly from the wide section  503 . 
   The central contact beam  52  includes a first spring arm  520  extending upwardly and rearwardly from the front end  500  and a second spring arm  522  extending downwardly and forwardly from the first spring arm  520 . The first spring arm  520  has a first curved portion  52   a  connecting with the front end  500  of the intermediate portion  50  and a second curved portion  52   b  connecting with the second spring arm  522 . The second curved portion  52   b  is higher than the first curved portion  52   a . The central contact beam  52  deforms downwardly about the first curved portion  52   a  to achieve an electrical contact between the second curved portion  52   b  and a complementary contact of the complementary connector. The second spring arm  522  has a free end  52   c  for abutting against the intermediate portion  50  to prevent an undue deformation of the central contact beam  52  during the insertion of the complementary contact. 
   The side contact beams  54  include a pair of vertical arms  540  and a pair of resilient side arms  542  extending rearwardly from top ends of the vertical arms  540 . The side arms  542  have a pair of connecting portions  54   a  projecting toward each other at free ends thereof for electrically contacting with the complementary contact. 
   In the preferred embodiment, the tail portion  56  has two pairs of gripping wings  560  adapted to extend and wrap around the corresponding cable  3  by means of a crimp tool (not shown). 
   Referring to  FIGS. 7–12 , each contact  5  is crimped to a corresponding cable  3  with gripping wings  560  surroundingly engaging outside surfaces of the exposed conductive core  30  and the outer insulator  32 . Each contact  5  with a corresponding cable  3  electrically connecting thereto is then inserted into a corresponding cavity  40  of the housing  4  from the rear face  402 . The wide section  503  of the intermediate portion  50  has opposite side edges  506  received in a corresponding pair of slits  44  to prevent the contact  5  from moving upwardly and forwardly. The slits  44  can also function as guiding slits during the insertion of the contact  5  into the cavity  40 . The tab  504  of the intermediate portion  50  is received in the corresponding slot  42  of the housing  4  for preventing the contact  5  from moving rearwardly. The cable assembly  1  of the present invention is thus formed. 
   When the cable assembly  1  mates with the complementary connector, the complementary contact simultaneously contacts with the second curved portion  52   b  the connecting portions  54   a  of a corresponding contact  5  to achieve multiple contacting points therebetween. It is noted that the side contact beams  54  do not move or rotate with the deformation of the central contact beam  52  during the insertion of the complementary contact since the side contact beams  54  integrally extend from the intermediate portion  50 . Thus, a reliable engagement is ensured between the contact  5  and the complementary contact. 
   It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated broad general meaning of the terms in which the appended claims are expressed.