Patent Publication Number: US-6988913-B2

Title: Electrical contact

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is generally related to a type of electrical contacts, and more particularly, to a type of electrical contacts used in card connectors, battery connectors or board to board connectors. 
   2. Description of Related Art 
   A variety of electrical connectors are widely used in electronic devices for transmitting signals between them. Electrical connectors each comprise a plurality of electrical contacts for contacting with electrical elements of a complementary connector. For achieving reliable and continuous signals between the electronic devices, the electrical contact must be applied with adequate normal force when the electrical connector with the electrical contacts assembled mates with the complementary connector. Inadequate normal force between the electrical contacts and electrical elements of the complementary connector easily causes signal instability. 
   U.S. Pat. No. 5,971,809 (the &#39;809 patent) discloses a conventional electrical connector. Referring to  FIG. 4  adapted from  FIG. 2(A)  of the &#39;809 patent, the connector  1  includes an insulated housing  10  and a plurality of first electrical contacts  110  and second electrical contacts  111 . The housing  10  comprises a plurality of passageways  1011  in which the first and the second electrical contacts  110 ,  111  respectively are secured and a plurality of protrusions respectively formed in corresponding passageways. Each electrical contact comprises a mating portion  1101  for electrically contacting with electrical element of a complementary connector, a preload portion  1104  extending forwardly from the mating portion to abut against corresponding protrusion of the housing, a solder portion  1103  for connecting the connector with a printed circuit board and a retention portion  1102  between the mating portion and the solder portion for securing the electrical contact to corresponding passageway of the housing. The second electrical contact comprises a mating portion  1111  for electrically contacting with the electrical element of the complementary connector, a preload portion  1114  extending forwardly from the mating portion to abut against corresponding protrusion, a retention portion  1112  and a solder portion  1113  extending rearwardly from the retention portion. The mating portions of the first and the second electrical contacts are pressed to deform elastically by normal force occurred when the electrical connector is engaging with the complementary connector. The first and the second electrical connector respectively comprise a preload portion which prearranged some elastic deformation to the first and the second electrical contacts. Thus, the normal force applied on the electrical contacts is equivalent to the normal force added by the prearranged elastic deformation and the actual elastic deformation. 
   However, with the development toward miniaturization and integration of the electronic devices, the electrical connector not only become more and more smaller than before but also required to transmitting signal more stably. This trend of development induces that the electrical contacts should be loaded by adequate normal force. After the electrical connector connecting or disconnecting with its complementary connectors several times, electrical contacts are pressed by the normal force between the electrical contacts and electrical elements of the complementary connector to offset from its correct positions. Thus, the configuration of the conventional electrical connector cannot fulfill the requirement of providing adequate normal force on the electrical contacts. 
   Hence, an improved type of electrical contacts is highly desired to overcome the aforementioned disadvantages of the prior art. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a type of electrical contacts, whose structure can enable an electrical connector with this type of electrical contacts assembled to transmitting signals more stably. 
   In order to achieve the object set forth, a type of electrical contacts is provided. Each electrical contact comprises a mating portion for electrically contacting with an electrical element of a complementary connector, a preload portion extending forwardly from the mating portion, a retention portion extending rearwardly from the mating portion to engage with the housing and a solder portion extending from the retention portion to solder the electrical connector to a printed circuit board. The mating portion comprises a tab projecting from one end thereof along a direction which is opposite to that of the preload portion. 
   Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with attached drawings: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of an electrical connector, with a plurality of electrical contacts in accordance with the present invention assembled thereto; 
       FIG. 2  is a perspective view of the electrical contact; 
       FIG. 3  is a perspective view of the electrical contact in accordance with another embodiment of the present invention; and 
       FIG. 4  is a sketch, cross-sectional view of an electrical connector of prior art. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiment of the present invention. 
   Referring to  FIG. 1  and  FIG. 2 , an electrical connector  4  comprises an insulated housing  40  and a plurality of electrical contacts  2 . The housing  40  includes a plurality of passageways  41  for respectively receiving the electrical contacts  2  and a plurality of protrusions  43  respectively projecting from an inner wall  42  of corresponding passageway  41 . Each electrical contact  2  comprises a mating portion  23  for electrically contacting with an electrical element of a complementary connector (not shown), a preload portion  24  extending forwardly from one end  232  of the mating portion  23 , a retention portion  22  extending rearwardly from the mating portion  23  to engage with the housing  40  and a solder portion  21  extending from the retention portion  22  to solder the electrical connector  4  to a printed circuit board (not shown). The mating portion  23  comprises a tab  25  projecting from the end  232  thereof adjacent to the preload portion  24  along a direction which is opposite to that of the preload portion  24 , a slot  26  formed between the end  232  and the other end  231  thereof adjacent to the retention portion  22  and an arc-shaped contact portion  233 . The tab  25  comprises an arm  253  and an angled portion  251  curved along a direction which is opposite to that of the contact portion  233 . 
   When the electrical contacts  2  are respectively assembled into the passageways  41  of the housing  40 , the preload portions  24  of the electrical contacts  2  abut against the protrusions  43  to prearrange some elastic deformation to the electrical contacts  2 . When the complementary connector is inserted into the housing  40  of the electrical connector  4 , the electrical contacts  2  offset from its original position and extend into the passageways  41 , and the angled portion  251  of tabs  25  is pressed to abut against and slide along the inner walls  42  of the passageways  41 . In the process of insertion of the complementary connector the housing  40  reacts to the electrical contacts  2  via the angled portions  251 . As a result, the normal force acted on the electrical contacts  2  is highly increased. Accordingly the electrical connector with this type of electrical contact  2  assembled thereto can fulfill the requirements of the electronic devices. 
   Referring to  FIG. 3 , an electrical contact  3  in accordance with another embodiment of the present invention is shown. Each electrical contact  3  has a similar structure as the electrical contact  2 , but the electrical contact  3  has a tab  35  projecting from one end  321  adjacent to a retention portion  32  of the electrical contact  3  along a direction which is the same as that of a preload portion  34  of the electrical contacts  3 . 
   The electrical contacts  2 ,  3  are not only used in a card connector but also can be used in a battery connector or a board to board connector. With the configuration of the electrical contacts  2 ,  3 , when any electrical connector with this type of electrical contacts  2 ,  3  assembled mates with its complementary connector, the normal force between the electrical contacts  2 ,  3  and electrical elements of the complementary connector is enough to enable the electrical connectors to transmitting signals stably and continuously. 
   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 by the broad general meaning of the terms in which the appended claims are expressed.