Abstract:
A cigarette lighter adaptor for a portable electronic device is provided. The adaptor includes a handle and dongle coupled together by way of a mechanical stepper joint. The stepper joint includes a hinge that engages to resist angular forces applied to the handle relative to the dongle. In one preferred embodiment, the stepper joint includes a convex member with protruding members that act as gear teeth. The stepper joint has a corresponding concave member with détentes. When assembled, these features create the détente positions for the stepper joint. The détente positions are accomplished by allowing the dongle to translate along the axis of the adaptor away from the handle. The stepper joint is preferably held together with an elastic member wrapped about a pin within the stepper joint.

Description:
BACKGROUND 
     1. Technical Field 
     This invention relates generally to power adaptor for a portable electronic device that is mechanically structured so as to fit in the cigarette lighter of a vehicle, and more specifically to a cigarette lighter adaptor having a moveable, mechanical stepper joint to allow movement between the dongle and handle of the cigarette lighter adaptor. 
     2. Background Art 
     Many modern vehicles are provided with cigarette/cigar lighters. The lighter usually comprises a circular, socket aperture with a removable lighter cap. When actuated, electrical current flows through a high resistance element in the lighter cap, thereby causing the element to glow red-hot. A cigarette or cigar can then be ignited from the glowing metal. 
     The lighter socket can also be used to power a large range of portable appliances, for example, mobile phones, car vacuum cleaners, lap-top computers, televisions, chiller cabinets, etc. Recently, the sockets on their own (without the cigarette lighter cap) have been provided in cars, off road and other vehicles. Sockets without cigarette lighter caps are often labeled simply as “power” sockets. While some appliances are powered directly from the socket itself, others may require an adaptor. 
     The typical cigarette lighter adaptor has a dongle and a handle. The dongle is a plug member that is inserted into the vehicle lighter socket. The dongle is elongate with a first electrical contact at one end. The first electrical contact connects to a co-operating electrical contact at the base of the lighter socket. To ensure a good and reliable connection, it is preferable if the first electrical contact is mounted on the dongle such that the contact is resiliently biased towards the end of the dongle. In prior art adaptors, the first contact is electrically and mechanically connected to the remainder of the adapter via a spring. The dongle also includes a second electrical contact that is generally a pair of curved leaf springs that provide both an electrical connection and a mechanical friction force with/against the lighter socket. 
     Most prior art adaptors are manufactured in a single, rigid piece. Thus, the angle of the handle—the portion of the adaptor that couples to the portable electronic device—is dependent upon the geometric orientation of the lighter socket. Some designers have attempted to add moveability to the handle (relative to the socket) by adding hinged members. For example, U.S. Pat. No. 6,478,628, issued to Ming, teaches an adaptor with a hinged dongle. The problem with adaptors like than in the &#39;628 patent is that their dongle-handle interface comprises a friction-based mechanical connection. In other words, the only thing that keeps the dongle at the proper angle relative to the handle is the friction applied by the handle material (usually plastic) against the dongle material (also usually plastic). After only a few dongle-handle angle adjustments, this joint can wear, thereby causing the handle to sag. 
     There is thus a need for an improved adaptor with a more robust handle-dongle interface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates one preferred embodiment of a cigarette lighter adaptor with a mechanical stepper joint in accordance with the invention. 
     FIG. 2 illustrates an exploded view of an adaptor in accordance with the invention. 
     FIG. 3 illustrates a bottom, left, isometric, exploded view of the adaptor. 
     FIG. 4 illustrates a top, right, back, isometric, exploded view of an adaptor in accordance with the invention. 
     FIG. 5 illustrates a close-up, cut away view of a stepper joint in accordance with the invention. 
     FIG. 6 is FIG. 5, with perspective rotated approximately 30 degrees. 
     FIG. 7 illustrates a left, elevational view of a preferred embodiment of the stepper joint. 
     FIG. 8 illustrates a view of the protruding members disengaged from the détentes. 
     FIGS. 9-12 illustrate alternate means for coupling the handle to the dongle. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the invention is now described in detail. Referring to the drawings, like numbers indicate like parts throughout the views. As used in the description herein and throughout the claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise: the meaning of “a,” “an,” and “the” includes plural reference, the meaning of “in” includes “in” and “on.” 
     Referring now to FIG. 1, illustrated therein is one preferred embodiment of a cigarette lighter adaptor  100  with a mechanical stepper joint  101  in accordance with the invention. The adaptor  100  comprises a handle  106  and a dongle  103 . The handle  106  and dongle  103  are preferably constructed from a rigid plastic material, like ABS, polycarbonate, or equivalent, and are preferably manufactured by way of an injection molding process. The dongle  103  preferably comprises at least a first  104  and second  105  electrical contacts for coupling to corresponding electrical contacts in an automotive lighter socket. 
     The stepper joint  101  (recited in detail below) is optionally covered by a rubber casing  102  in FIG.  1 . The rubber casing  102  serves to protect any openings in the stepper joint  101  from debris, as well as providing an aesthetically pleasing appearance. 
     For exemplary purposes, the adaptor  100  of FIG. 1 is shown as a hands-free, speaker phone adaptor comprising a microphone  107  and speaker  108 , although the invention is not so limited. The adaptor  100  could equally comprise a power supply, a charger with charging circuitry, a mechanical holder for the electronic device or any combination or equivalent thereof. The adaptor  100  includes an interface  109  for coupling to a portable electronic device (not shown) like a cellular telephone, radio, pager, laptop computer or television. The interface  109  is preferably a cable with a device specific connector mounted thereto, but may equally be a fixed connecter mounted to the handle  106 . 
     Referring now to FIG. 2, illustrated therein is an exploded view of an adaptor in accordance with the invention. In FIG. 2, the details of the stepperjoint are more clearly illustrated. The stepper joint preferably comprises a convex member  201  mounted to the handle  106  having at least one protruding member  202 . The protruding members  202  look like “teeth” about the convex member. Note that the handle  106  is preferably comprised of two halves  106 A,  106 B, thereby allowing circuitry, speakers and the like to be easily disposed within the two halves  106 A,  106 B. 
     The convex member  202  mates with a corresponding concave member  204  mounted on the dongle  103 . The dongle  103  of FIG. 2 is illustrated in a sectional view so as to better illustrate the interior components. The concave member  204  has at least one détente  203  that corresponds to at least one protruding member  204 . 
     The convex member  201  and concave member  204  are preferably coupled together by way of an elastic member  205  that includes an elongated portion  206 . The elastic member is preferably made of a stretchy, rubber material, and is similar in many respects to a robust rubber band or belt. The elongated portion  206  wraps about a pin  207  disposed within the dongle  103 , thereby exerting a force against the pin  207  in the direction of the handle  106 . In the hands-free speaker phone application, the elastic member  205  may be tailored to match the edges of the upper and lower housings  106 A,  106 B, so as to serve the dual function of a gasket. 
     While FIG. 2 is a top, right, back, isometric, exploded view of an adaptor in accordance with the invention, FIG. 3 illustrates a bottom, left, isometric, exploded view of the adaptor. The perspective of FIG. 3 illustrates an optional circuit board  300  having electronic components disposed thereon to be seen. The circuit board  300  may be disposed in either the top  106 B or bottom  106 A housing. The circuit board  300  is electrically coupled to the first and second electrical contacts (elements  104 ,  105  of FIG. 1) by current conducting materials. 
     Referring now to FIG. 4, illustrated therein is a top, right, back, isometric, exploded view of an adaptor in accordance with the invention, similar to the view of FIG.  2 . The difference between FIG.  2  and FIG. 4 lies with the elastic member  205 . In FIG. 4, the elongated portion  206  of the elastic member  205  has been folded back upon itself. Both the elastic member  205  and the elongated portion  206  include apertures  401  that mechanically couple about a corresponding number of bosses  402  disposed within the handle  106 . 
     The folding of FIG. 4 is shown without the elongated member  206  wrapping around the pin  207  of the dongle  103  for illustrative purposes. The elongated member  206  in practice wraps about the pin  207 , although the pin may be inserted into the loop formed by the elongated member  206  after folding as manufacturing procedures require. 
     Referring now to FIG. 5, illustrated therein is a close-up, cut away view of a stepper joint in accordance with the invention. The elongated member  206  has been folded about the pin of the dongle  103 . (Note that the pin is not clearly visible in FIG. 5 due to the fact that the elongated member  206  is wrapped about it. Also note that only half of the pin is shown due to the fact that the dongle  103  has been cut away to expose the interior components.) The elongated member attaches to the bosses  402  disposed within the handle  106 . In this preferred embodiment, the elongated member  206  also serves as the gasket  205 . 
     FIG. 5 offers an illustration of the protruding members  202  disposed on the convex member  201  mating with the détentes  203  in the dongle  103 . FIG. 6 is the same view as shown in FIG. 5, although the perspective has been rotated by approximately 30 degrees. The rotation allows visibility of the pin  207  seated within the elongated member  206 . 
     Referring now to FIG. 7, illustrated therein is a left, elevational view of a preferred embodiment of the stepper joint. As previously shown, the elongated member wraps  206  about the pin  207 . (Note that both the handle  106  and the dongle  103  have been cut away for illustrative purposes.) The pin  207  is inserted into the convex member  201  through a non-circular aperture  208 . The non-circular aperture  208  has a diameter that is longer running along a line from handle  106  to dongle  103  than the diameter that is normal to this line. This non-circular shape facilitates engagement of the protruding members  202  and the détentes  203 . To disengage the stepper joint, one pulls the handle  106  away from the dongle  103 , thereby disengaging the protruding members  202  from the détentes  203 . This “pulling” causes the elongated member  206  to stretch, thereby exerting a force that tries to pull the handle  106  and dongle  103  together. 
     With the protruding members  202  and détentes  203  disengaged, one may rotate the handle  106  relative to the dongle  103  the desired amount. When the appropriate handle-dongle geometric relationship has been established, one releases the handle, thereby allowing the elongated member  206  to relax, causing the protruding members  202  to again engage the détentes  203 . The engagement resists angular forces placed upon the stepper joint by way of heavy portable electronic devices being coupled to the handle  106 . Note that for exemplary purposes here, the adjustment is recited as occurring when the handle  106  is pulled from the dongle  103 . In practice, the adaptor would normally be coupled to a socket, and the second electrical contact ( 105  of FIG. 1) exerts force against the walls of the socket. This allows one to disengage the protruding members  202  from the détentes  203  simply by pulling the handle  106  away from the socket. FIG. 8 illustrates a view of the protruding members  202  disengaged from the détentes  203 . 
     As stated in the previous paragraph, the stepper joint may be actuated by pulling the handle  106  and dongle  103  away from each other, thereby disengaging the protruding members  202  from the détentes  203 . The adaptor may also be adjusted by application of sufficient angular force to the handle  106  relative to the dongle  103 . The application of this force causes the protruding members  202  to act as cam members that facilitate stretching of the elongated member  206 . When the angular force is removed, the elongated member  206  relaxes, thereby causing the protruding members  202  to seat in their corresponding détentes  203 . 
     While the preferred embodiments of the invention have been illustrated and described, it is clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the following claims. For example, while one preferred embodiment provided an elongated member wrapped around the pin, other methods of exerting a coupling force between the handle and dongle could also be used. 
     Referring now to FIG. 9, illustrated therein is an alternate means for coupling the handle  106  to the dongle  103 . The method of FIG. 9 involves a coiled spring  901  coupled between the pin  207  of the dongle  103  and an anchor  902 . The anchor is preferably a boss or screw disposed within the handle  106 . 
     FIG. 10 illustrates another alternative coupling. In FIG. 10, a cantilever arm  903 , coupled to the convex member  201  is loaded against the pin  207 . When the handle  106  and dongle  103  are pulled apart, the cantilever arm  903  deflects, thereby exerting force against the pin. Other alternative coupling means include a springy metal leaf spring  904  shown in FIG. 11 and a compression rubber block  905  as shown in FIG.  12 .