Abstract:
An electrical power adapter employs a magnetically coupled mechanism to retract and deploy prongs used to interface with an electrical receptacle. The magnetically coupled mechanism is linearly displaced by a user, converting the linear displacement to rotary motion, pivoting the retractable prongs between a deployed position and a retracted position. When the retractable prongs are in the deployed position the adapter may be mated with a receptacle and when in the retracted position the adapter has a reduced physical size.

Description:
FIELD 
     The present invention relates generally to electrical power adapters and in particular to electrical power adapters for use with standard alternating current (AC) power sockets employed in residential and commercial buildings. 
     BACKGROUND 
     Electrical power adapters are used for a wide variety of applications, facilitating the supply of electrical power to a myriad of electronic devices including smart-phones, media players, and other personal electronic systems. 
     As smart-phones, media players, and other electronic systems become more compact, a limiting factor on the size of the package in which the systems are shipped and sold may be the size of the electrical power adapter used to charge the electronic system. As an example, a portable media player may be packaged along with a BS1363 (Type G) electrical power adapter, used in the United Kingdom, where the media player is actually smaller than the electrical power adapter. Such large power adapters may therefore contribute to increased shipping costs for the electrical systems and may also be difficult for the user to conveniently store and transport. 
     New electrical power adapters may require new features to reduce their physical size, enabling reduced shipping costs and added convenience for the user. 
     SUMMARY 
     Embodiments of the invention pertain to electrical power adapter connectors for use with a variety of electronic devices. In some embodiments, the electrical power adapter connectors are configured to provide reduced size and improved usability. A reduction in size allows for a reduction in total packaging, which may enable lower packaging and/or shipping costs. 
     Some embodiments of the present invention relate to improved electrical power adapter connectors having retractable prongs that are pivoted from a retracted position in which the retractable prong is positioned adjacent to the adapter housing, to a deployed position in which the retractable prong extends away from the adapter housing, and can be inserted into an electrical outlet. 
     One particular embodiment employs a magnetic drive mechanism positioned within the adapter housing and operatively coupled to rotate the retractable prong between the refracted position and the deployed position. The magnetic drive mechanism includes a first and second driver magnet spaced a first axial distance apart that interact with first and second driven magnets attached to a rotatable shaft fixed to the rotatable prong. The magnetic drive mechanism is axially displaced by the user from a first position in which the first driver magnet is adjacent to the first driven magnet and the second driver magnet is displaced from the second driven magnet, to a second position in which the second driver magnet is adjacent to the second driven magnet and the first driver magnet is displaced from the first driven magnet. The driver and driven magnets are operatively coupled such that when the magnetic drive mechanism moves from the first position to the second position, the retractable prong is pivoted to the retracted position, and when the magnetic drive mechanism moves from the second position to the first position the retractable prong is pivoted to the deployed position. 
     In further embodiments, the retractable prong may be operatively coupled to a second rotatable shaft such that when one shaft rotates, both shafts rotate. Second rotatable shaft may be secured to one or more additional prongs such that when one prong is deployed or refracted, all prongs are deployed or retracted. In some embodiments there may be additional rotatable shafts that are operatively coupled to the retractable prong. 
     Other embodiments may incorporate a magnetic actuation mechanism and a rotatable carriage attached to a prong that is pivotable between a deployed and a retracted position. Rotatable carriage comprises first and second driven magnets spaced an axial distance apart. The magnetic actuation mechanism is positioned within the housing and operatively coupled to rotate the retractable prong between the refracted position and the deployed position. The magnetic actuation mechanism includes first and second driver magnets spaced a second axial distance apart and attached to a shaft. The shaft is axially moved by the user from a first position in which the first driver magnet is adjacent to the first driven magnet and the second driver magnet is displaced from the second driven magnet, to a second position in which the second driver magnet is adjacent to the second driven magnet and the first driver magnet is displaced from the first driven magnet. When the magnetic actuation mechanism moves from the first position to the second position, the retractable prong is pivoted to the retracted position, and when the magnetic actuation mechanism moves from the second position to the first position, the retractable prong is pivoted to the deployed position. 
     To better understand the nature and advantages of the present invention, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present invention. Also, as a general rule, and unless it is evident to the contrary from the description, where elements in different figures use identical reference numbers, the elements are generally either identical or at least similar in function or purpose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an electrical power adapter in a deployed position according to some embodiments; 
         FIG. 2  is a front perspective view of an electrical power adapter transitioning between a deployed position and a retracted position according to some embodiments; 
         FIG. 3  is a front perspective view of an electrical power adapter in a retracted position according to some embodiments; 
         FIG. 4  is a rear perspective view of an electrical power adapter with a portion of the housing removed according to some embodiments; 
         FIG. 5  is a left side perspective view of a magnetic drive mechanism and an electrical prong in a deployed position according to some embodiments; 
         FIG. 6  is a right side perspective view of a magnetic drive mechanism and an electrical prong in a deployed position according to some embodiments; 
         FIG. 7  is a left side perspective view of a magnetic drive mechanism and an electrical prong in a retracted position according to some embodiments; 
         FIG. 8  is a right side perspective view of a magnetic drive mechanism and an electrical prong in a retracted position according to some embodiments; 
         FIG. 9  is a plan view of driver and driven magnets according to some embodiments; 
         FIG. 10  is a plan view of driver and driven magnets according to some embodiments; 
         FIG. 11  is a plan view of driver and driven magnets according to some embodiments 
         FIG. 12  is a plan view of driver and driven magnets according to some embodiments; 
         FIG. 13  is a left side perspective cross-section of a magnetic actuation mechanism and a carrier in a deployed position according to some embodiments; 
         FIG. 14  is a left side perspective cross-section of a magnetic actuation mechanism and a carrier in a retracted position according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Certain embodiments of the present invention relate to electrical power adapters. While the present invention can be useful for a wide variety of electrical power adapters, some embodiments of the invention are particularly useful for electrical power adapters that can be reduced in size, as described in more detail below. 
     Many electronic devices such as smart-phones, media players, and tablet computers have electrical power adapters that facilitate battery charging. As an example, a three prong power adapter  100  compatible with the BS1363 (Type G) standard in the United Kingdom is illustrated in  FIG. 1 . Power adapter  100  has three rectangular prongs forming an isosceles triangle and extending away from housing  102 . Line and neutral prongs  105  are approximately 4 mm by 8 mm and 17.7 mm long, on centers spaced 22.2 mm apart. Earth prong  110  is approximately 4 mm by 8 mm and 22.7 mm long. In other embodiments power adapters having different physical shapes and dimensions may be used. 
     In this embodiment, prongs  105 ,  110  may be rotatably retractable.  FIG. 2  illustrates prongs  105 ,  110  in a partially retracted position.  FIG. 3  illustrates prongs  105 ,  110  in a fully retracted position where they are adjacent housing  102 . Further, in  FIG. 3 , prongs  105 ,  110  are stowed within line and neutral slots  115  and earth slot  120 , respectively. Thus, power adapter  100  has reduced physical size in  FIG. 3  where prongs  105 ,  110  are in the retracted position, rotated approximately 90 degrees, as compared to  FIG. 1  where the prongs are in the deployed position. As illustrated in  FIG. 2 , in some embodiments, pivot point  198  for line and neutral retractable prongs  105  is proximate a first end  180  of line and neutral slots  115  while pivot point  199  for earth prong  110  is proximate an end of earth slot  120  opposite the first end  180  of the line and neutral slots. Thus, in some embodiments, line and neutral prongs  105  may pivot in an opposite direction as ground prong  110 . More specifically, as illustrated in  FIG. 2 , when transitioning from the deployed position to the refracted position, line and neutral prongs  105  may pivot up while ground prong  110  may pivot down. 
       FIG. 4  illustrates power adapter  100  with a portion of housing  102  removed, showing the internal construction of an embodiment. Retractable earth prong  110  is coupled to rotatable shaft  405  within housing  102  such that the retractable earth prong can be pivoted from a retracted position to a deployed position. Magnetic drive mechanism  410  is positioned within housing  102  and is operatively coupled to rotate retractable earth prong  110  between the retracted position and the deployed position. Magnetic drive mechanism  410  includes first driver magnet  415  and second driver magnet (not shown in  FIG. 4 ) spaced a first axial distance apart (shown in greater detail in subsequent figures). First driven magnet  420  and second driven magnet (not shown in  FIG. 4 ) are attached to rotatable shaft  405  and are spaced a second axial distance apart (shown in greater detail in subsequent figures). 
     An actuator (not shown) such as a depressible button or a slide, for example, may be operatively coupled to magnetic drive mechanism  410  to axially move the magnetic drive mechanism from a first position in which first driver magnet  415  is adjacent first driven magnet  420  (as shown in  FIG. 4 ) and second driver magnet (not shown in  FIG. 4 ) is displaced from second driven magnet (not shown in  FIG. 4 ), to a second position in which the second driver magnet (not shown in  FIG. 4 ) is adjacent to the second driven magnet (not shown in  FIG. 4 ) and the first driver magnet is displaced from the first driven magnet. These configurations will be illustrated in greater detail in subsequent figures. Magnetic drive mechanism  410  may have one or more slides  417  that enable the drive mechanism to move in a rectilinear motion without rotating. Magnetic drive mechanism  410  may be magnetically coupled to rotatable shaft  405  such that when magnetic drive mechanism moves from the first position to the second position, retractable earth prong  110  is pivoted to the refracted position and when the magnetic drive mechanism moves from the second position to the first position the retractable prong is pivoted to the deployed position (illustrated in  FIG. 4 ). 
     Thus, the actuator is coupled to a magnetic actuation mechanism enabling a non-contact method of driving the retractable prongs of the power adapter. This drive mechanism offers a low friction, low wear system that may enable electrical isolation between components. 
       FIG. 4  also illustrates rotatable shaft  405  operably coupled to second rotatable shaft  425  with bands  430 . Bands  430  transfer rotational motion from rotatable shaft  405  to second rotatable shaft  425 , such that when retractable earth prong  110  moves between the retracted position and the deployed position, retractable line and neutral prongs  105  (see  FIG. 1 ) similarly move between the retracted position and the deployed position, as illustrated in  FIGS. 1-3 . 
       FIG. 5  illustrates a left-side view of magnetic drive mechanism  410  in the first position and retractable earth prong  110 , with housing  102  and rotatable shaft  405  removed for clarity. Retractable earth prong  110  is shown in the deployed position. First driver magnet  415  is adjacent first driven magnet  420 . As used herein, adjacent means when the outer surfaces of the driver and driven magnets are approximately aligned, or approximately coplanar. When first driver magnet  415  and first driven magnet  420  are adjacent one another, magnetic forces from first driver magnet  415  magnetically attract first driven magnet  420  causing rotatable shaft  405  (see  FIG. 4 ) to rotate in a first direction. As illustrated in  FIG. 5  the first direction would be counter-clockwise if earth prong  110  is rotating from the retracted position to the deployed position. Rotatable shaft  405  is affixed to retractable earth prong  110  so when the rotatable shaft rotates the retractable earth prong deploys. Magnetic poles “N” and “S” are identified in  FIG. 5  and are illustrated for example only; other orientations, configurations, quantities and numbers of magnets may be employed without departing from the invention. As known in the art, magnetic forces will cause the “N” pole of first driver magnet  415  to attract the “S” pole of first driven magnet  420 . Similarly, magnetic forces will cause the “S” pole of first driver magnet  415  to attract the “N” pole of first driven magnet  420 , engendering rotation of rotatable shaft  405  (see  FIG. 4 ) and deployment of earth prong  110 . In alternative embodiments repulsive forces (i.e., “N” to “N” and “S” to “S”) may also be used to engender rotation of rotatable shaft  405  (see  FIG. 4 ) and deployment of earth prong  110 . 
       FIG. 6  illustrates a right-side view of magnetic drive mechanism  410  in the first position and retractable earth prong  110 , with housing  102  and rotatable shaft  405  removed for clarity. Retractable earth prong  110  is shown in the deployed position and magnetic drive mechanism  410  is in the first position. Second driver magnet  615  is displaced from first driven magnet  620 . As used herein, displaced means when the outer surfaces of magnets are not aligned or they are not coplanar. When magnets  615 ,  620  are displaced, magnetic forces from second driver magnet  615  have very little magnetic attraction to second driven magnet  620 . Thus, when magnetic drive mechanism  410  is in the first position, the magnetic forces between first driver magnet  415  and first driven magnet  420  (see  FIG. 5 ) are much stronger than the magnetic forces between second driver magnet  615  and second driven magnet  620 . In some embodiments the magnetic surface area of the magnets may be increased to increase magnetic forces by fabricating the magnets in an arcuate geometry as shown. More specifically,  FIG. 6  illustrates all magnets having an arcuate shape wherein first and second driven magnets  420 ,  620  have outer radii  421 ,  621 , respectively, that are smaller than inner radii  416 ,  616  of first and second driver magnets  415 ,  615 , respectively. 
     As further illustrated in  FIG. 6 , first axial distance  630  from first driver magnet  415  to second driver magnet  615  is greater than a second axial distance  635  between first driven magnet  420  and second driven magnet  620 . The difference between axial distances  630 ,  635  is such that either first driver magnet  415  and first driven magnet  420  are aligned (in a first position of magnetic drive mechanism  410  illustrated in  FIG. 5 ) or second driver magnet  615  and second driven magnet  620  are aligned (in a second position of magnetic drive mechanism  410  illustrated in  FIG. 6 ). In other embodiments first axial distance  630  may be less than second axial distance  635 . 
       FIG. 7  illustrates a left-side view of magnetic drive mechanism  410  in the second position and retractable earth prong  110 , with housing  102  and rotatable shaft  405  removed for clarity. Retractable earth prong  110  is shown in the retracted position and magnetic drive mechanism  410  is in the second position. First driver magnet  415  is displaced from first driven magnet  420 . When magnets  415 ,  420  are displaced from one another, second driver magnet  415  has very little magnetic attraction to second driven magnet  420 . 
       FIG. 8  illustrates a right-side view of magnetic drive mechanism  410  in the second position and retractable earth prong  110 , with housing  102  and rotatable shaft  405  removed for clarity. Retractable earth prong  110  is shown in the retracted position and magnetic drive mechanism  410  is in the second position. Second driver magnet  615  is adjacent second driven magnet  620 . When magnets  615 ,  620  are adjacent one another, magnetic forces from first driver magnet  615  magnetically attract first driven magnet  620  causing rotatable shaft  405  (see  FIG. 4 ) to rotate in a second direction. As illustrated in  FIG. 7  the second direction would be clockwise if earth prong  110  is rotating from the deployed position to the retracted position. Thus, when magnetic drive mechanism  410  is in the second position, the magnetic forces between second driver magnet  615  and second driven magnet  620  are much stronger than the magnetic forces between first driver magnet  415  and first driven magnet  420 . Magnetic poles “N” and “S” are identified and are illustrated for example only; other orientations, configurations, quantities and numbers of magnets may be used without departing from the invention. As known in the art, magnetic forces will cause the “N” pole of second driver magnet  615  to attract the “S” pole of second driven magnet  620 . Similarly, magnetic forces will cause the “S” pole of second driver magnet  615  to attract the “N” pole of second driven magnet  620 . In alternative embodiments repulsive forces may be used to engender rotation of rotatable shaft  405  (see  FIG. 4 ). 
       FIGS. 9 through 12  illustrate various example configurations of driver magnets and driven magnets. These are illustrative examples only and in no way limit the scope of the invention. For example, the driven magnets do not need to be disposed within the inner radius of the driver magnets. The driver magnets may be larger and be disposed outside of the radius of the driver magnets. Further, the driver and driven magnets do not need to be nested as illustrated in  FIGS. 9 through 12 , but they may be axially displaced (e.g., the driver and driven magnets may be approximately the same size and may both be disposed on the same axis where they may be axially adjacent to one another. Myriad configurations, geometric orientations and quantities of driver and driven magnets may be used without departing from the invention. Additionally, the configuration of the poles in  FIGS. 9 through 12  are for example only and other configurations of the poles are within the scope of the invention. 
     In some embodiments, various orientations and quantities of driver and driven magnets may be used to change the way in which retractable earth prong  110  moves, and may also be used to apply a preload to the prong. Additional magnets may be used to alter the magnetic forces between the driver and driven magnets to change the way in which the retractable prongs move in relationship to the change in position of the actuation mechanism. In other embodiments a the additional magnets may be used to apply a preload to the prongs.  FIG. 9  illustrates an embodiment having two driver magnets  915 ,  916  and one driven magnet  920 .  FIG. 10  illustrates an embodiment having two driver magnets  1015 ,  1016  and two driven magnets  1020 ,  1021 .  FIG. 11  illustrates an embodiment having two driver magnets  1115 ,  1116  and three driven magnets  1120 ,  1121 ,  1122 .  FIG. 12  illustrates an embodiment having two driver magnets  1215 ,  1216  and four driven magnets  1220 ,  1221 ,  1222 ,  1223 . A prong preload may be used to secure retractable earth prong  110  in the deployed or retracted positions where the prong rests against a hard stop. The preload may be used to ensure that while in the deployed position, retractable earth prong  110  is positioned against a hard stop for accurate alignment. The preload magnitude may also be sufficient to prevent unintended rotation of the prong when inadvertent external forces act on the prong (e.g., when a user misses the holes in the receptacle connector). A preload in the retracted position may ensure the prong is held firmly against a hard stop to mitigate vibration or rattling of the prong during transport of power adapter  100  (see  FIG. 3 ). 
     Other embodiments may incorporate a magnetic actuation mechanism  1310  and a rotatable carriage  1315 , as illustrated in  FIGS. 13 and 14 .  FIG. 13  illustrates a left-side cross-sectional perspective view of magnetic actuation mechanism  1310  in a first position, and rotatable carriage  1315  and retractable earth prong  110 , with housing  102  (see  FIG. 1 ) removed for clarity. 
       FIG. 14  illustrates a left-side perspective cross-sectional view of magnetic actuation mechanism  1310  in the second position, rotatable carriage  1315  and retractable earth prong  110 , with housing  102  (see  FIG. 1 ) removed for clarity.  FIG. 13  illustrates retractable earth prong  110  in the deployed position whereas  FIG. 14  illustrates retractable earth prong  110  in the retracted position. Retractable prong  110  is coupled to rotatable carriage  1315  within housing  102  such that the retractable prong can be pivoted from a retracted position in which the retractable prong is positioned adjacent to housing (see  FIG. 3 ), to a deployed position in which the retractable prong extends away from the housing (see  FIG. 1 ), and can be inserted into an electrical outlet. 
     Rotatable carriage  1315  further comprises a first driven magnet  1320  and second driven magnet  1325  attached to the rotatable carriage and spaced an axial distance apart. Magnetic actuation mechanism  1310  is positioned within housing  102  (see  FIG. 1 ) and operatively coupled to rotate retractable prong  110  between the retracted position and the deployed position. Magnetic actuation mechanism  1310  includes first driver magnet  1330  and second driver magnet  1335  attached to shaft  1340 . An actuator (not shown) may be operatively coupled to shaft  1340  to axially move the shaft and first and second driver magnets  1330 ,  1335 , respectively, from a first position (see  FIG. 13 ) in which first driver magnet  1330  is adjacent to first driven magnet  1320  and second driver magnet  1335  is displaced from second driven magnet  1325 , to a second position (see  FIG. 14 ) in which second driver magnet  1335  is adjacent to second driven magnet  1325  and first driver magnet  1330  is displaced from first driven magnet  1320 . More specifically, when magnetic actuation mechanism  1310  moves from the first position to the second position, retractable prong  110  is pivoted to the retracted position and when the magnetic actuation mechanism moves from the second position to the first position, the retractable prong is pivoted to the deployed position. In some embodiments an actuator may comprise a button or a lever. 
     In some embodiments, driver and driven magnets are arcuate as illustrated previously, however in other embodiments they may comprise other shapes. As illustrated in  FIG. 13 , driven magnets may be parallelepipeds while other embodiments may employ different shapes. In further embodiments, earth prong  110  may not be the driven prong and the line and/or neutral prongs may be the driven prong. In other embodiments all prongs may be driven prongs. 
     It will be appreciated that the magnetic actuation mechanism described herein is illustrative and that variations and modifications are possible. For instance, referring back to  FIG. 4 , magnetic drive mechanism  410  may be employed in a myriad of applications such as a door latch, a valve positioner, an electronic switch or other application where a translation to rotation or rotation to translation mechanism may be employed. For example, rotatable shaft  405  may be coupled to a rotatable door knob and actuation mechanism  410  may be coupled to a linearly retractable door latch. A user may rotate the door knob causing rotatable shaft  405  to rotate and in turn causing magnetic actuation mechanism  410  to linearly displace, engaging or disengaging a door latch. In further embodiments, actuation mechanism  410  may be coupled to a translatable button, and rotatable shaft  405  may be coupled to an electronic switch or a valve having one or more positions. When a user translates the button, the switch or valve may be rotated to one or more new positions. Other applications are within the scope of the invention where such a low friction, non-directly coupled, back drivable translation/rotation mechanism may be employed. Actuation mechanism  410  may have multiple linear positions and rotatable shaft  405  may have multiple associated linear positions. The non-directly coupled nature of the mechanism may be beneficial where electronic isolation is desired. 
     In the foregoing specification, embodiments of the invention have been described with reference to numerous specific details that may vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the invention, and what is intended by the applicants to be the scope of the invention, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction.