Patent Document

BACKGROUND OF INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates generally to plugs for power ports. More particularly, the invention relates to safety plugs with a child-proof mechanism.  
         [0003]     2. Background Art  
         [0004]     With more and more electronic devices, such as personal radios, cassette players, CD players, televisions, and DVD players, proliferating to our living environment outside the homes, new cars and boats often are equipped with multiple power ports. The days of having only one power port to be shared between a cigarette lighter and other electronic devices seem to be gone. While the additional power ports provide convenience to the users, they may present hazards to small children.  
         [0005]     The additional power ports in the automobiles or boats are typically covered with simple devices to prevent foreign objects from being accidentally introduced into them.  FIG. 1  shows one example of a typical cover used in most power ports. As shown, a cover  52 , which is typically made of plastic, is attached to the opening  53  of the power port  51 . The cover  52  is pressed into the opening  53  to close the power port. The cover  52  engages the power port by interference fit and can be easily removed by a curious child.  
         [0006]     Once the cover  52  is opened, the electrical terminals (not shown) inside the power port  51  become accessible to the curious little hands and fingers. A child may stick his fingers into the power port. This may result in injuries to the child. Alternatively, the child may shove foreign objects into the power port. If paper clips or liquids are introduced into the power port, damages may result to the automobiles or boats, and the child may be injured.  
         [0007]     Therefore, it is desirable that better power port covers or plugs that cannot be easily removed by children are available. In addition, it is desirable that such covers or plugs may serve other useful functions.  
       SUMMARY OF INVENTION  
       [0008]     In one aspect, the invention relates to safety plugs for power ports such as those found in an automobile or a boat. A safety plug in accordance with one embodiment of the invention includes a body having a first end adapted to be inserted into a power port; a locking device connected to the body for reversibly engaging an inside of the power port; and a control device operatively coupled to the locking device for disengaging the locking device from the inside of the power port, wherein the control device comprises a child-proof mechanism.  
         [0009]     A safety plug in accordance with one embodiment of the invention may further include at least one electrical contact on the first end of the body for conducting electricity from the power port; and an electrical device disposed proximate to a second end of the body and electrically connected to the at least one electrical contact, wherein the electrical device is configured to be powered by the electricity from the power port.  
         [0010]     Other aspects and advantages of the invention will be apparent from the following description and the appended claims. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0011]      FIG. 1  shows a prior art power port cover attached to a mobile power port.  
         [0012]      FIG. 2  shows a schematic of a safety plug in accordance with one embodiment of the invention.  
         [0013]      FIG. 3  shows a safety plug in accordance with another embodiment of the invention.  
         [0014]      FIG. 4  shows a safety plug in accordance with another embodiment of the invention.  
         [0015]      FIG. 5  shows a safety plug illustrating a locking device in accordance with one embodiment of the invention.  
         [0016]      FIG. 6  shows a safety plug illustrating another locking device in accordance with one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0017]     Embodiments of the invention relate to safety plugs for power ports, such as those found in automobiles and boats. A safety plug in accordance with embodiments of the invention includes a locking device. The locking device can be disengaged by a control device with a child-proof mechanism. Therefore, a safety plug in accordance with embodiments of the invention can prevent children from pulling the safety plug out of a power port.  
         [0018]      FIG. 2  illustrates a schematic of a safety plug in accordance with one embodiment of the invention. As shown, the safety plug  100  comprises a body  10  that has a first end  11  and a second end  12 . The first end  11  of the safety plug  100  is adapted to be inserted into a power port (or electric socket, shown as  51  in  FIG. 1 ). The safety plug  100  also includes a locking device  13 , which is controlled by a control device  20 .  
         [0019]     The locking device  13  engages the inside of the power port (socket) to prevent it from being removed. In preferred embodiments, the locking device  13  is configured to the locked state by default. Alternatively, the locking device  13  may be switched to the locked state after it is inserted into a power port. To remove the safety plug  100  from the power port, the control device  20  is activated. Activation of the control device  20  disengages the locking device  13  and converts it to the unlocked state to allow the safety plug  100  to be removed.  
         [0020]     In accordance with embodiments of the invention, the control device  20  has a child-proof mechanism that may be activated in a counter-intuitive manner such that a child is less likely to pull the safety plug  100  out of the power port. Examples of child-proof mechanisms may include the following. The control device  20  may need to be “pushed” in, while the safety plug  100  is being “pulled” out of the power port. The control device  20  may need to be turned to a specific angular position, like a child-proof medicine bottle, before the safety plug  100  can be removed from the power port, The control device  20  may need to be turned to one direction and then the other, like a combination lock, before the locking mechanism  13  is disengaged from inside the power port. One of ordinary skill in the art would appreciate that other variations of the child-proof mechanism may be used with embodiments of the invention, and, therefore, the invention is not limited to these specific examples.  
         [0021]     The control device  20 , which may include a shaft slidably disposed in the body  10 , is attached at its first end  21  to the locking device  13 , while the second end of the control device  22  may protrude from the second end  12  of the body  10  of the safety plug  100 . The protrusion of the second end  22  allows a force to be applied to rotate or push the control device  20  towards the first end  11  of the body  10 . Thus, the force needed to unlock the locking device  13  is applied in an opposite or orthogonal direction relative to the force needed to pull the safety plug  100  out of a power port.  
         [0022]      FIG. 2  illustrates minimum features of a safety plug  100  in accordance with one embodiment of the invention. According to some embodiments of the invention, the safety plug may further include other components to enhance its utility. As shown in  FIG. 3 , a safety plug  200  in accordance with one embodiment of the invention also includes an attachment  15 . The attachment  15  may be attached to the second end  12  of the body  10  or to the second end  22  of the control device  20 . If the attachment  15  is attached to the second end  12  of the body  10 , then it may have an opening to allow access to the control device  20 . Alternatively, the control device  20  may protrude from the side of the attachment  15 .  
         [0023]     The attachment  15  may be any item that enhances the utility and/or aesthetic of the safety plug  200 , such as a picture, a display, a sign (e.g., a no smoking sign), an air freshener, a clock, or a connector for other electronic devices. If the attachment  15  is (or is for) an electronic or electrical device, such as a clock or any electronic device, or a connector for such a device, then the safety plug  200  may include conductors (electrical contacts) to transmit electricity from the power port. Examples of a display may include light-emitting diode display, a liquid-crystal display, a thin-film-transistor display, and a plasma display. Examples of an electrical connector may include a jack for a stereo mini plug, a jack for an RCA plug, etc.  
         [0024]      FIG. 4  shows a safety plug  300  in accordance with another embodiment of the invention. As shown, the safety plug  300  includes two conductors (electrical contacts)  31 ,  32  and a wire  33  for providing electrical power to the attachment  15 . As shown, the electrical contact  31  is adapted to contact the positive terminal in the power port and the electrical contact  32  is to provide a current return. The current return electrical contact  32  may not be needed, if the body  10  is made of a conductive material and can provide the conductive path. If the control device  20  is made of a conductive material, the electrical contact  31  may be connected directly to the control device  20 . Otherwise, the electrical contact  31  may be connected to the attachment  15  via a conductive wire (not shown).  
         [0025]     The locking device  13  may use any reversible mechanism that can prevent the safety plug from being pulled out of a power port by a child.  FIG. 5  shows one embodiment of a locking device  13  that comprises an adjustable diameter member. As shown, the locking device  13  is made of a flexible material that is disposed between the first end  11  and the second end  12  of the body  10 . The flexible material, for example, may be rubber, plastic, or the like. The flexible material permits the locking device  13  to change its diameter. While a single fold structure is illustrated for the locking device  13  in  FIG. 5 , one of ordinary skill in the art would appreciate that other configurations may be employed without departing from the scope of the invention. For example, the locking device  13  may have multiple folds as in an accordion, or other suitable structures.  
         [0026]     As shown in  FIG. 5 , a spring  17  is provided to bias the control device  20  in the up position so that the locking device  13  is at its maximum diameter (i.e., the locked state). To unlock the safety plug  400  from a power port, the diameter of the locking device  13  can be reduced by pressing the control device  20  towards the first end  11  of the body  10 . Thus, to remove the plug, two forces of opposite directions need to be applied. This counter-intuitive mechanism can prevent a child from pulling the safety plug out of a power port without adult assistance.  
         [0027]     The embodiment shown in  FIG. 5  is for illustration only, other configurations of the locking device  13  are possible. For example, the locking device  13  may have selected portions protruding from slots cut in the body  10 . Alternatively, the locking device  13  may not be made of a flexible material.  
         [0028]      FIG. 6  shows another embodiment of the locking device  13  that comprises one or more protruding members  19  adapted to extend from the body  10  to engage a power port (not shown). The protruding members  19  are linked to the control device  20  by levers  18  such that when the control device  20  is pushed in, the protruding members  19  are pulled towards the body  10  to disengage the safety plug from a power port (not shown). The levers  18  and the protruding members  19  shown in  FIG. 6  are for illustration only. One of ordinary skill in the art would appreciate that many modifications are possible without departing from the scope of the invention. For example, the protruding members  19  may be hinged at one of its ends to the body  10 , and the levers  18  may be replaced by springs. The levers or springs  18  are generally referred to as a “retracting mechanism” in this description.  
         [0029]     Advantages of the invention may include the following. A safety plug in accordance with the invention can be easily deployed to block a power port to prevent potential injuries to children. A safety plug of the invention has a locking device with a child-proof control mechanism that unlocks the locking device in a counter-intuitive manner. Therefore, children are not expected to be able to remove the safety plugs from the power ports.. In addition, a safety plug of the invention may further provide other functions such as a sign or a display. The safety plug may also provide a conduit to the power terminals in the power port such that other electrical or electronic devices may be conveniently connected.  
         [0030]     While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein.

Technology Category: h