Abstract:
A frameless battery cavity formed in a device enclosure retains a battery housing. Cantilever tabs on a battery end of a wall of the device housing have detents that forcibly engage the battery housing when the battery housing is fully inserted into the battery cavity. The detents are restrained from springing away from the battery housing when it is fully inserted by notches in a battery cover. The notches engage the detents after the battery has been fully inserted. The battery cover is secured in the opening to the battery cavity so that the detents are prevented from expanding away from the battery, and thus releasing the battery from the cavity, unless the cover is removed by a user. A guiding mechanism guides the battery housing into the cavity to facilitate electrical engagement of a connection between the battery housing and the device housing.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority under 35 U.S.C. 119(e) to U.S. provisional patent application No. 60/721,430 entitled “Two/four cell frameless battery compartment with passive capture mechanism,” which was filed Sep. 28, 2005, and is incorporated herein by reference in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates generally to communication devices, and more particularly to a battery compartment/cavity and capture mechanism for multiple sizes of batteries. 
   BACKGROUND 
   Community antenna television (“CATV”) networks have been used for more than four decades to deliver television programming to a large number of subscribers. Increasingly, CATV networks are used by providers to provide data services to subscribers. For example, cable modems used in a broadband cable modem termination system (“CMTS”) compete with digital subscriber lines (“DSL”) and DSL modems used therein, which are typically implemented and supported by telephone companies. DSL service is typically provided over the same wires as a residence&#39;s telephone service. 
   Cable modems, on the other hand, use the CATV cabling over which CATV programming is provided. Some cable television and cable data providers compete with telephone companies by offering telephony services over the CATV network using Internet protocol. This is known in the art as ‘voice over IP’ (“VoIP”). 
   Conventional telephony networks provide electrical current from a central location to a user&#39;s telephony equipment for dial tone and off-hook signaling, for example. The power supplied from the telephone company&#39;s central location is provided from a utility company&#39;s power lines at the central office location under normal conditions, and is typically supplemented by a diesel generator in case off site power from the power company is interrupted. Thus, power for telephony service is always available; in an emergency, the local 911 operator can always be reached. 
   Although a CATV network often supplies some AC power for network devices, a subscriber&#39;s device or devices are typically powered by household AC current. Since most consumers do not have a diesel generator to back up off-site power supplied by a local utility company, batteries are typically used to provide a backup in case off-site power is lost. This allows a VoIP-over-CATV subscriber to place a telephone call during a power outage, including placing a call to a 911 operator in case an emergency situation requires contacting police, fire, paramedic, or medical personnel. 
   To increase reliability and reduce physical size, cable modem and other devices that support VoIP-over-CATV do not use the standard dry-cell batteries widely known to consumers in the familiar AAA, AA, C, D and 9-volt configurations. This is because rechargeable batteries are used so that immediately following a power outage, reasonable assurances are provided that the batteries will be operative. While power is being supplied from an off-site utility company, charge on the back-up batteries is being maintained or recharged. However, to maintain quality control and to facilitate particular size and shapes of devices, proprietary battery packs, preferably lithium ion, are provided by equipment manufactures to cable operators. 
   Depending on the price point of a given communication device, different size batteries may be specified. Typically, a device&#39;s housing is designed based on a particular battery configuration of a given size. Therefore, the device is typically constrained to always using the same battery size and configuration. 
   Communication device housings, as well as electronic device houses generally, typically include a compartment or well that receives and locates a battery or battery pack. Typically, the battery is inserted into the compartment/well and retaining ‘door’ or cover is placed over the compartment. The door/cover typically is snapped or screwed into place over the compartment and serves to retain the battery in the battery compartment. However, with respect to a snap-in door, if the device is dropped, and the door pops open, the battery may pop out of the device&#39;s battery compartment and become electrically disconnected. This scenario could present a problem if the user of the electrical device is in the middle of a critical operation. 
   Therefore, there is a need in the art for a device housing that can accept multiple battery sizes so that a user can specify the battery size based on his or her needs. Furthermore, there is a need for a battery compartment that does not require a frame, which is an extra structure within a electronics device housing, housings which are typically molded plastic or formed metal, to locate and retain a battery. 
   SUMMARY 
   A device enclosure includes opposing walls that form part of a housing, wherein each of the opposing walls has a battery end that partially forms the cavity. Each battery end defines an elongate edge of an opening of the battery cavity and at least one battery end forms at least one cantilever retaining tab. The cantilever tab, or tabs, have detents on a battery side of the battery end of the corresponding opposing wall in which the cantilever tabs are formed. 
   At least one of the opposing walls defines at least one rigid tab proximate the at least one cantilever tab and the at least one rigid tab forms at least one guide channel. 
   A battery housing including at least one guide rail for engaging with the at least one guide channel cooperates with the with the battery cavity to guide the battery into the cavity and to located a battery connection port formed into the battery housing with a corresponding battery connection formed into the device enclosure. A securable battery cover having notches for engaging with the detents when the cover is in a secured position restrains the cantilever tabs from flexing away from the battery cavity, thus aiding the detents in holding the battery/battery housing in the battery cavity. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a frameless battery cavity receiving a four-cell battery. 
       FIG. 2  illustrates a frameless battery cavity receiving a two-cell battery. 
       FIG. 3  illustrates a frameless battery cavity in a device housing. 
       FIG. 3A  illustrates a detail view of a cantilever tab and surrounding rigid portions of a battery end of an opposing wall of a device housing. 
       FIG. 4  illustrates the battery side of a battery cover. 
       FIG. 5  illustrates a detent (detached from the cantilever tab for clarity) cooperating with a battery housing. 
   

   DETAILED DESCRIPTION 
   As a preliminary matter, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many methods, embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the following description thereof, without departing from the substance or scope of the present invention. 
   Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purposes of providing a full and enabling disclosure of the invention. This disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. 
   Turning now to  FIG. 1 , a device housing  2  is shown. Housing  2  includes two opposing walls, with opposing wall  4  shown in the figure. The wall that opposes wall  4  is a wall parallel to wall  4 . It will be appreciated that the opposing walls need not be parallel planes, as the walls form the outer housing and for aesthetic purposes the walls may be curved outward with respect to one another, or one wall may be planar while the other is curved. For purposes of discussion of  FIG. 1 , features formed into wall  4  will be described. Similar features are preferably included in the wall opposing wall  4 , but need not be. Wall  4  includes a battery end  6 . Battery end  6  forms elongate edge  8 , which defines battery compartment opening  10 . 
   Cantilever tabs  12  are formed into the battery end of wall  4 . Cantilever ends  12  are separated from rigid portions  14 , which are stiffened by guide channels  16 . The separation of cantilever ends  12  from rigid portions  14  forms separation gaps  18 . Thus, cantilever ends  12  can flex perpendicular to wall  4  with respect to rigid portions  14 . 
   When a battery housing  20 , typically containing battery cells, a circuit and a connector coupled thereto, is inserted into opening  10 , contact edges of battery housing  20  interfere with detents  24 , which are formed into cantilever tabs  12 . Thus, the insertion force of battery housing  20  entering opening  10  causes cantilever tabs  12  to move away from contact edge  22  as the contact edge engages with detents  24 . Preferably, and will be shown in greater detail in other figures, the contact edge  22  is curved and detents  24  are similarly curved where they contact the contact edge when a battery housing is installed in housing  2 . Thus, when battery housing  20  is fully inserted through opening  10 , detents  24  retain the battery housing into the opening of device housing  2 . It will be appreciated that detents  24  extent past elongate edge  8  in a direction away from opening  10 . Thus, when battery cover  26  is secured over opening  10  with hinge tabs  28  and snap  30  retained by catch edges  32 , notches formed on the back side (not shown in  FIG. 1 , but shown in other figures) engage the portions of detents  24  that extend past elongate edge  8  to prevent cantilever tabs  12  from flexing away from battery housing  20 , thus assisting the cantilever tabs in retaining the battery housing inside the battery cavity to which opening  10  provides passage of the battery. Guide rails  33  are shown on battery housing  20 . Guide rails may cooperate with guide channels  16  to facilitate guiding of the battery into the battery cavity of housing  2  so the electrical connections of the battery housing and the battery cavity properly couple. 
   Turning now to  FIG. 2 , device housing  2  is shown receiving battery housing  34  into opening  10 . In this embodiment, housing  2 , walls  4  and features formed therein are similar to those described above in reference to the description of  FIG. 1 , except battery housing  34  is smaller that battery housing  20 , which is shown in  FIG. 1 . Without battery housing  20  blocking the view,  FIG. 2  illustrates battery cavity  35 , which is partially defined by battery ends  6  and  36  and inner wall  37 . Other features shown in  FIG. 1  are shown for reference, including battery cover  26 , elongate edge  8  and guide rails  33 . 
   Turning now to  FIG. 3 , the opening  10  defined by housing  2  is shown without a battery housing. Thus, the battery end  36  of opposing wall  38  is shown. In addition, a battery connection  40  that cooperatively couples with a corresponding connection on one of the battery housings discussed in reference to the description of other FIGS. is shown. The battery connections engage as the battery housing is inserted into opening  10  of device housing  2 . The connections transfer energy from the battery cells inside the battery housing to circuitry inside the device housing  2 . 
   In an aspect, battery connection  40  and the corresponding battery connection on the backside of battery cover  30  illustrated in  FIGS. 1 and 2 , may be formed so as to guide battery cover  20  or  34  into opening  10 . In another aspect, guide rails on the battery housing and guide channels  16  cooperate when slidingly engaged to guide the battery into opening  10  so that battery connection  40  and the corresponding connection on the back of battery cover  20  illustrated in  FIGS. 1 and 2  mechanically and electrically engage one another. 
   The embodiment shown in the figure illustrates guide channels  16  formed into battery ends  6  and  36  of opposing walls  4  and  38 , respectively. However, guide channels  16  may be formed only in one or the other of opposing walls  4  and  38 . Alternatively, the guide rails could be formed into the battery ends  6  and  36 , with the guide channels formed into battery housing  20  or  34 . It will be appreciated that, as discussed above, the guide channels or guide rails may not be formed into the battery ends or battery housing at all—the battery connection  40  and corresponding connection formed into the backside of the battery housing  20  or  34  may be formed to properly guide the battery housing into battery cavity  35 . Section A shows a more detailed view of a guide channel and detent arrangement. 
   Turning now to  FIG. 3A , a detailed view of a guide channel  16  and detent  24  arrangement are shown. It will be appreciated that the view is looking at a battery side of a battery end of opposing wall  39 . Thus, channels  16  can slidingly engage with guide rails on a battery housing. It will be appreciated, however, that guide channels and guide rails are but one embodiment for guiding a battery housing into the battery cavity, and other means, such as, for example, cooperating guiding battery connections on the battery housing and the back wall of the battery cavity. 
   As discussed above, rigid portions  14  and cantilever tab  12  are formed into battery end  36 , which is part of opposing wall  38 . Channel  16  is formed into rigid portion  14  and detent  24  is formed into cantilever tab  12 . Since distal points  42  (distal with respect to elongate edge  8 ) is where gaps  18  begin, cantilever tab  12  can flex with respect to rigid portions  14 . Although the entire cantilever tab  12  may flex along gaps  18 , the movement of the cantilever tab approximates movement that would occur if a spring-loaded hinge between distal points  42  attached the cantilever tab to rigid portions  14 . Thus, when a battery housing is inserted into the battery cavity in direction  44 , the battery housing contacts leading edges  46  of detents  24 , thereby causing cantilever tab  12  to flex along the ‘hinge’ between distal points  24  in direction  48 . 
   Turning now to  FIG. 4 , the back side, or inner side facing the battery cavity of battery cover  26  is illustrated. Notches  50  engage with detents  24  shown in other figures, to prevent cantilever tabs of one opposing wall from flexing in away from the other opposing wall. Reinforcing ridges  52  extent toward the battery (out of the page in the figure) farther than surface  54 , thus preventing detents  24  (shown in other figures) from flexing in directions  56  and  58  when battery cover  26  is snapped into place over opening  10  shown in  FIGS. 1 and 2 . 
   Turning now to  FIG. 5 , the forward side  60  of battery housing  20  or  34  is illustrated. As described above, in an embodiment that uses them, guide rails  33  may engage guide channels shown in other figures that are formed into the rigid portions of the battery end of the opposing walls. Detent  24  is shown detached from the cantilever retaining tab for clarity. The surface  62  is the surface that would be formed if detent  24  were detached from the cantilever retaining tab as shown in the figure. 
   It will be appreciated that contact surface  22  is curved and the surface of detent  24  that contacts contact surface  22  has a similar shaped curve. When battery housing  20  or  34  is seated into the battery cavity, the natural spring force of the flexible cantilever tab out of which surface  62  is formed exerts force in direction  58  to prevent movement of battery housing  20  or  34  in direction  64  out of the battery cavity. Extent  66  of detent  24  that extends past elongate edge  8 , which is shown in other figures, the extent starting at break line  68 , engages with one of notches  50  shown in  FIG. 4 . This engagement of extent  66  and notch  50  prevents movement of detent  24  in direction  56  when the battery is seated into the battery cavity and battery cover  26  is installed covering opening  10 . It will be appreciated that alignment pad  70 , or similar arrangement, may be used instead of guide rails to guide the battery housing  20  or  34  into the battery cavity so the proper alignment of battery connection  72  and complementary battery connection  40  shown in  FIG. 3  is made. In addition, the electrical contact means, such as, for example, metallic tabs coupled to a circuit board, could be manufactured to be rigid enough to self-guide themselves into complementary metallic clips coupled to a circuit board located within the device housing. 
   These and many other objects and advantages will be readily apparent to one skilled in the art from the foregoing specification when read in conjunction with the appended drawings. It is to be understood that the embodiments herein illustrated are examples only, and that the scope of the invention is to be defined solely by the claims when accorded a full range of equivalents.