Abstract:
An exemplary cable connector plug ( 20 ) includes a contact ( 21 ) and an insulator ( 25 ). The first contact includes a contact portion ( 210 ) and an extension portion ( 211 ) extending from the contact portion along an axis of the cable connector plug. The first contact further includes a hooking portion ( 2115 ) provided at the extension portion. The insulator surrounds the hooking portion, and is lockingly engaged with the hooking portion such that when the extension portion is moved along an axis of the cable connector plug, the first insulator correspondingly moves in unison with the extension portion. The cable connector plug has good mechanical strength and stability.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to two co-pending U.S. patent applications, application Ser. No. 11/672,862, filed on Feb. 8, 2007, entitled “CABLE CONNECTOR PLUG HAVING CONTACT WITH CURVED EXTENSION PORTION”, wherein the inventor is Wu-Kuang Chen et al, and application Ser. No. 11/672,872, filed on Feb. 8, 2007, entitled “CABLE CONNECTOR PLUG HAVING CONTACT WITH ANTI-ROTATION MEMBER”, wherein the inventor is Wu-Kuang Chen et al. Such applications have the same assignee as the present application and have been concurrently filed herewith. The disclosures of the above identified applications are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical connector plugs, and more particularly to a cable connector plug used in a connector for transmitting audio signals or other signals. 
     2. Discussion of the Related Art 
       FIG. 5  is a side cross-sectional view of a conventional cable connector plug  10 . The cable connector plug  10  includes a first metallic contact  11 , a second metallic contact  12 , a third metallic contact  13 , a fourth metallic contact  14 , and a plurality of insulators  15 . The metallic contacts  11 ,  12 ,  13 ,  14  are electrical conductors, and are insulated from each other by the insulators  15 . 
     The first contact  11  includes a contact portion  110 , an extension portion  111  extending rearwardly from the contact portion  110  along an axis of the cable connector plug  10 , and a rear portion  112  extending rearwardly from the extension portion  111 . The extension portion  111  includes a first shaft portion  1111 , a neck portion  1112 , and a second shaft portion  1113 . The neck portion  1112  interconnects the first shaft portion  111  and the second shaft portion  1113 . 
     The second and third contacts  12 ,  13  respectively include an annular contact portion  120 ,  130 , a cylindrical extension portion  121 ,  131  extending rearwardly from the contact portion  120 ,  130 , and a rear portion  122 ,  132  extending rearwardly from the extension portion  121 ,  131 . The fourth contact  14  includes a cylindrical contact portion  140 , an annular extension portion  141  extending rearwardly from the contact portion  140 , and a rear portion  142  extending from the extension portion  141 . The extension portions  111 ,  121 ,  131 ,  141  of the first, second, third, and fourth contacts  11 ,  12 ,  13 ,  14  are coaxially arranged in that order from an inside to an outside of the cable connector plug  10 . Accordingly, diameters of the extension portions  111 ,  121 ,  131 ,  141  increase in that sequence. The contact portions  110 ,  120 ,  130 ,  140  of the contacts  11 ,  12 ,  13 ,  14  are insulated from each other by a plurality of annular insulating ring portions (not labeled) of the insulators  15 . The extension portions  111 ,  121 ,  131 ,  141  of the contacts  11 ,  12 ,  13 ,  14  are insulated from each other by a plurality of cylindrical portions (not labeled) of the insulators  15 . 
     The rear portion  112  of the first contact  11  extends rearwardly beyond the insulators  15  for soldering with a first wire (not shown) of a cable (not shown). A rearmost part of the rear portion  122  of the second contact  12  is exposed for soldering with a second wire (not shown) of the cable. The other part of the rear portion  122  of the second contact  12  is embedded between the corresponding insulators  15 . A rearmost part of the rear portion  132  of the third contact  13  is exposed for soldering with a third wire (not shown) of the cable. The other part of the rear portion  132  of the third contact  13  is embedded between the corresponding insulators  15 . The rear portion  142  of the fourth contact  14  extends perpendicularly outward from the insulator  15  that is between the third and fourth contacts  13 ,  14 , and is for soldering with a fourth wire (not shown) of the cable. 
     Generally, a diameter of the first shaft portion  1111  is greater than that of the second shaft portion  1113 . A shape of the neck portion  1112  is a conical frustum having an end at the first shaft portion  1111  and an opposite end at the second shaft portion  1113 . When the cable connector plug  10  is pulled out of a mating socket (not shown) of a housing (not shown) of a complementary connector (not shown), the first contact  11  is liable to become detached from the adjoining insulator  15 . When this happens, the cable connector plug  10  may become loosened or even break apart. 
     What is needed, therefore, is a new cable connector plug that can overcome the above-described shortcomings. 
     SUMMARY 
     A cable connector plug according to a preferred embodiment includes a contact and an insulator. The contact includes a contact portion and an extension portion extending from the contact portion along an axis of the cable connector plug. The extension portion includes a first portion adjacent to the contact portion, a second portion, and a neck portion interconnecting the first portion and the second portion. The extension portion further includes a hooking portion provided at an end of the neck portion where the neck portion connects to the first portion. The insulator surrounds the hooking portion, and is lockingly engaged with the hooking portion such that when the extension portion is moved along a direction coinciding with an axis of the cable connector plug, the first insulator correspondingly moves in unison with the extension portion. A maximum diameter of the hooking portion is greater than a diameter of the first portion where the first portion connects to the neck portion. 
     Other novel features and advantages will become more apparent from the following detailed description of various embodiments, when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present cable connector plug. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, and all the views are schematic. 
         FIG. 1  is an isometric view of a cable connector plug according to a first preferred embodiment of the present invention. 
         FIG. 2  is a side, cross-sectional view of the cable connector plug of  FIG. 1 , taken along line II-II thereof. 
         FIG. 3  is a side, cross-sectional view of a cable connector plug according to a second preferred embodiment of the present invention. 
         FIG. 4  is a side, cross-sectional view of a cable connector plug according to a third preferred embodiment of the present invention. 
         FIG. 5  is a side, cross-sectional view of a conventional cable connector plug. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference will now be made to the drawings to describe preferred embodiments of the present cable connector plug, in detail. 
     Referring to  FIGS. 1 and 2 , a cable connector plug  20  according to a first preferred embodiment of the present invention is shown. The cable connector plug  20  includes a first contact  21 , a second contact  22 , a third contact  23 , a fourth contact  24 , and a plurality of insulators  25 . The contacts  21 ,  22 ,  23 ,  24  are made of metallic material, and are insulated from each other by the insulators  25 . The first contact  21  includes a contact portion  210 , an extension portion  211  extending rearwardly from the contact portion  210  along an axis of the cable connector plug  20 , and a rear portion  212  extending rearwardly from the extension portion  211 . The extension portion  211  includes a first shaft portion  2111 , a neck portion  2112 , and a second shaft portion  2113 . 
     The second and third contacts  22 ,  23  respectively include an annular contact portion  220 ,  230 , a cylindrical extension portion  221 ,  231  extending rearwardly from the contact portion  220 ,  230 , and a rear portion  222 ,  232  extending rearwardly from the extension portion  221 ,  231 . The fourth contact  24  includes a cylindrical contact portion  240 , an annular extension portion  241  extending rearwardly from the contact portion  240 , and a rear portion  242  extending from the extension portion  241 . The extension portions  211 ,  221 ,  231 ,  241  of the first, second, third, and fourth contacts  21 ,  22 ,  23 ,  24  are coaxially arranged in that order from an inside to an outside of the cable connector plug  20 . Accordingly, diameters of the extension portions  211 ,  221 ,  231 ,  241  increase in that sequence. The contact portions  210 ,  220 ,  230 ,  240  of the contacts  21 ,  22 ,  23 ,  24  are insulated from each other by a plurality of ring portions (not labeled) of the insulators  25 . The extension portions  211 ,  221 ,  231 ,  241  of the contacts  21 ,  22 ,  23 ,  24  are insulated from each other by a plurality of cylindrical portions (not labeled) of the insulators  25 . 
     The rear portion  212  of the first contact  21  extends rearwardly beyond the insulators  25  for soldering with a first wire (not shown) of a cable (not shown). A rearmost part of the rear portion  222  of the second contact  22  is exposed for soldering with a second wire (not shown) of the cable. The other part of the rear portion  222  of the second contact  22  is embedded between the corresponding insulators  25 . A rearmost part of the rear portion  232  of the third contact  23  is exposed for soldering with a third wire (not shown) of the cable. The other part of the rear portion  232  of the third contact  23  is embedded between the corresponding insulators  25 . The rear portion  242  of the fourth contact  24  extends perpendicularly outward from the insulator  25  that is between the third and fourth contacts  23 ,  24 , and is for soldering with a fourth wire (not shown) of the cable. 
     The cable connector plug  20  can be manufactured by way of insert molding. In a typical process, firstly, the contacts  21 ,  22 ,  23 ,  24  are manufactured by a machining method. Secondly, the cable connector plug  20  is integrally assembled by an insert molding method. In particular, the contacts  21 ,  22 ,  23 ,  24  are coaxially aligned in a mold. Molten insulating material is injected into the mold and fills spaces between the contacts  21 ,  22 ,  23 ,  24 . The cooled insulating material forms the insulators  25  of the cable connector plug  20 . 
     The first and second shaft portions  2111 ,  2113  of the cable connector plug  20  are both cylindrical. The neck portion  2112  is a conical frustum that interconnects the first shaft portion  2111  and the second shaft portion  2113 . A diameter of the first shaft portion  2111  is greater than that of the second shaft portion  2113 . The neck portion  2112  includes a larger circular end at the first shaft portion  2111 , and a smaller circular end at the second shaft portion  2113 . A diameter of the larger circular end of the neck portion  2112  is greater than that of the first shaft portion  2111 . Accordingly, the neck portion  2112  at the first shaft portion  2111  defines a hooking portion  2115 . The hooking portion  2115  is generally in the form of an annular step. The adjoining insulator  25  that is between the first and second contacts  21 ,  22  closely surrounds and contacts the hooking portion  2115  and the first shaft portion  2111  at the hooking portion  2115 . 
     When the cable connector plug  20  is pulled out of a mating socket of a housing of a complementary connector, the hooking portion  2115  helps to prevent shearing occurring as between the extension portion  211  of the first contact  21  and the adjoining insulator  25 . Therefore, the first contact  21  avoids becoming detached from the adjoining insulator  15 . That is, the cable connector plug  10  has good mechanical strength and stability, and avoids becoming loosened or breaking apart. 
     The contacts  21 ,  22 ,  23 ,  24  are made of metallic material having good electrical conductive capability, such as copper, aluminum, and so on. In order to ensure good electrical contact and attain an aesthetically pleasing surface, an anticorrosion coating can be formed on an outer surface of each of the contacts  21 ,  22 ,  23 ,  24 . The anticorrosion coating is preferably made of nickel. The insulators  25  are preferably made of polyamide resin. 
     In an alternative embodiment, the first and second shaft portions  2111 ,  2113  of the extension portion  211  can instead be rectangular columns, and the neck portion  2112  interconnecting the first and second shaft portions  2111 ,  2113  can be a four-sided pyramidal frustum. For example, the first and second shaft portions  2111 ,  2113  can be square columns, and the neck portion  2112  can be a square pyramidal frustum. In other alternative embodiments, the first and second shaft portions  2111 ,  2113  can be polygonal columns, and the neck portion  2112  can be a polygonal pyramidal frustum. In all embodiments, the first and second shaft portions  2111 ,  2113  can have any desired axial length. 
     Referring to  FIG. 3 , a cable connector plug  30  according to a second preferred embodiment of the present invention is shown. The cable connector plug  30  is similar in principle to the cable connector plug  20  of the first embodiment. However, the cable connector plug  30  includes of a first contact  31  having an extension portion  311 . The extension portion  311  includes a first shaft portion  3111 , and a second shaft portion  3113  connecting with the first shaft portion  3111 . A diameter of the first shaft portion  3111  is greater than that of the second shaft portion  3112 . The extension portion  311  further includes a hooking portion  3115  at an end of the first shaft portion  3111  where the first shaft portion  3111  connects with the second shaft portion  3113 . The hooking portion  3115  extends perpendicularly outward from a periphery of the end of the first shaft portion  3111 . 
     In this embodiment, the hooking portion  3115  is an annular flange or an annular bead. Accordingly, a diameter of the hooking portion  3115  is greater than that of the first shaft portion  3111 . When the cable connector plug  30  is pulled out of a mating socket of a housing of a complementary connector, the hooking portion  3115  helps to prevent shearing occurring as between the extension portion  311  of the first contact  31  and the adjoining insulator (not labeled). Therefore, the first contact  31  avoids becoming detached from the adjoining insulator. That is, the cable connector plug  30  has good mechanical strength and stability, and avoids becoming loosened or breaking apart. In one alternative embodiment, the diameter of the first shaft portion  3111  and the second shaft portion  3112  can be the same. 
     Referring to  FIG. 4 , a cable connector plug  40  according to a third preferred embodiment of the present invention is shown. The cable connector plug  40  is similar in principle to the cable connector plug  20  of the first embodiment. However, the cable connector plug  40  includes a first contact  41 . The first contact  41  includes a contact portion  410 , a columnar extension portion  411  extending rearwardly from the contact portion  410  along an axis of the cable connector plug  40 , and a hooking portion  413  defined at a part of the extension portion  411  near the contact portion  410 . In this embodiment, the hooking portion  413  includes an annular groove defined in the extension portion  411 . An adjoining insulator  45  closely surrounds and contacts the extension portion  411  including in the annular groove of the hooking portion  413 . When the cable connector plug  40  is pulled out of a mating socket of a housing of a complementary connector, the hooking portion  413  helps to prevent shearing occurring as between the extension portion  411  of the first contact  41  and the adjoining insulator  45 . Therefore, the first contact  41  avoids becoming detached from the adjoining insulator  45 . That is, the cable connector plug  40  has good mechanical strength and stability, and avoids becoming loosened or breaking apart. 
     It is should be noted that in alternative embodiments, the hooking portion can be provided adjacent to the contact portion of the first contact. For example, in the cable connector plug  40  of the third preferred embodiment, the annular groove can be defined adjacent to the contact portion  410  of the first contact  41 . This kind of configuration can similarly help to prevent shearing occurring as between the extension portion  411  of the first contact  41  and the adjoining insulator  45 , when the first contact  41  is pulled out of a mating socket of a housing of a complementary connector along a direction coinciding with an axis of the cable connector plug  40 . 
     It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, 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.