Abstract:
The present invention provides antenna assemblies for wireless devices where the antenna has a tip with at least one barb and a cap with at least one internal groove. The barb and groove mate to form a snap lock. The snap lock resists pressure tending to pull the cap off the antenna.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to antennas and, more particularly, to antennas having a snap on or friction fit cap at one end.  
         BACKGROUND OF THE INVENTION  
         [0002]    Both portable and non-portable wireless devices use many types of antennas and antenna systems. Many of the common antennas used today are mounted on the outside of the wireless device, such as on the chassis or housing. These antennas are classified generically as external antennas. Some common examples of these antenna are helical wound radiator antennas (a.k.a. stubby antennas), elongated radiator antennas (a.k.a. whip antennas), retractable whip antennas, and telescopic whip antennas to name a few. Another generic category of antenna is the internal antenna, which is generally less prone to damage because it is encased in the housing, but often not as efficient as an external antenna. Retractable and telescopic antennas combine the protection of internal antennas during periods of nonuse, and the efficiency of external antenna during use.  
           [0003]    Because of the increase in wireless technologies and communications, there has been an increased push for improvement of old designs and a development of new and innovative solutions in the design and function of antennas. Generally, the pushes fall largely into one of several categories, such as, better performance, reduced size, reduced weight, style, etc.  
           [0004]    One such area for improvement is the telescopic or retractable antenna. In particular, caps on the end of whip antennas is vulnerable and subject to damage due to normal operation. Normal operation requires a user to repeatedly extend and retract the antenna by pulling and pushing on the cap. Further, the cap is susceptible to damage from dropping the wireless device on the cap or catching the cap an object or edge. In addition, the whip antenna and subsequently the cap can be abused by uses, such abuses include, for example, chewing by nervous users, stirring hot drinks, and the like. Failure of the cap may seem trivial, but in some situations it could cause a catastrophic failure of the handset. For instance, the antenna may fall inside the wireless device, which could cause electrical shorting. Also, a wire antenna without a cap would be relatively sharp and could possibly poke the user.  
         SUMMARY OF THE INVENTION  
         [0005]    To attain the advantages of and in accordance with the purpose of the present invention, antenna assemblies with a cap are provided. The antenna assembly includes a flexible wire section having a proximate end and a distal end. The proximate end is coupled to a wireless device and a tip resides towards the distal end. The tip has at least one barb formed thereon. A cap has at least one mating surface and is installed on the tip such that the at least one mating surface engages the at least one barb.  
           [0006]    The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0007]    The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:  
         [0008]    [0008]FIG. 1 is a perspective view of a wireless device having an antenna consistent with the present invention,  
         [0009]    [0009]FIG. 2 is a perspective view of the telescopic whip type antenna of FIG. 1;  
         [0010]    [0010]FIG. 3 is a perspective view of the telescopic section of the whip type antenna of FIG. 2;  
         [0011]    [0011]FIG. 4 is a perspective, exploded view of the telescopic section and cap of the antenna of FIG. 2, and  
         [0012]    [0012]FIG. 5 is a cross sectional view of a cap and telescopic tube illustrative of one embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0013]    The present invention will now be described with reference to FIGS.  1  to  5 . With reference to FIG. 1, a cellular telephone  100  is shown with a retractable, telescopic whip antenna  102  mounted on cellular telephone  100 . FIG. 2 illustrates antenna  102  in more detail. As can be seen, antenna  102  has a flexible wire section  104 , and a telescopic tube portion  106 , which together make up the radiating portion of the antenna. A cap  108  is installed on the end of the telescopic tub. Flexible wire portion  104  has a proximate end  202  connected to cellular telephone  100  and a distal end  204 . Distal end  204  is connected to a receptacle  206  of telescopic tube portion  106 . Telescopic tube portion  106  also has a tip  208  opposite receptacle  206 . Tip  208  is adapted to receive cap  108 . While the present invention will be described in conjunction with a retractable, telescopic whip antenna, it should be understood that alternative style antennas could be equipped with only a cap and not a telescopic tube. Further, while shown that distal end  204  extends into a hollow of receptacle  206 , alternative configurations are possible. For example, distal end  204  could have a hollow portion in which receptacle  206  fits or the like. Further, telescopic tube portion  106  could be eliminated from the design, in which case cap  108  would be connected directly to distal end  204 .  
         [0014]    Referring now to FIG. 5, cap  108  installed on telescopic tube portion  106  is shown in more detail. Cap  108  can be manufactured numerous ways, but it is believed a simple injection molded part would be sufficient. Cap  108  has a base  502 , base sidewalls  504 , and a flanged top  506 . Base  502  has an outer edge  502   o  and an inner edge  502   i . Inner edge  502   i  defines a base opening  508  having a first diameter sufficient to fit snuggly over tip  208  of telescopic tube portion  106 . Extending internal from inner edge  502   i  are base opening inside walls  510  that contain an inside groove  512 . Inside groove forms an undercut geometry, which can be used for a snap lock feature (explained further below). Inside groove  512  extends from base opening inside walls  510  towards base sidewalls  504 . The remainder of cap  108  can be hollow or solid as a matter of design choice.  
         [0015]    Referring now to FIG. 4, tip  208  is shown with a barb  402 . Cap  108  is installed on tip  208  by forcing tip  208  into base opening  508 . The barb  402  interferers with the inside wall  510  until barb  402  snaps in inside groove  512 . Ideally, the inside diameter of inside groove  512  is the same diameter or bigger than a diameter of barb  402  so not to displace plastic material of cap  108  during normal operation. Thus, when fully installed, as shown in FIG. 3, barb  402  is captured within the inside groove  512  will resist pressure tending to pull cap  108  off tip  208 . While FIG. 5 shows a rib (or barb) and groove style connection, other connections are of course possible. Some non limiting examples include a pin and detent, a spring loaded arm and notch, a flange and shoulder matting surface, or the like. Also, while shown as singular connections, multiple grooves and barbs could be used.  
         [0016]    Alternative to the above (and not shown in the figures), tip  208  could be hollow such that external barb  402  could be replaced by an internal shoulder extending internal to hollow tip  208 . In this case, base  502  would have a flanged portion forming a mating shelf such that when installed, base  502  would slide in tip  208  until the mating shelf snapped in place below the internal shoulder. Thus, when fully installed the flanged mating shelf resting on the internal shoulder would resist pressure tending to pull cap  108  off tip  208 .  
         [0017]    Generally, the cap is designed to fit snuggly over or in tip  208  such that the interface between the flanged surfaces and the snugness combine to resist outward press. The system could be designed to ease installation by, for example making the opening diameter be slightly larger than the tip diameter. Alternatively, the barb feature could be removed and a friction fitting could be designed to hold the cap in place.  
         [0018]    While the invention has been particularly shown and described with reference to an embodiment thereof, it will be understood by those skilled in the art that various other changes in the form and details may be made without departing from the spirit and scope of the invention.