Abstract:
A socket provides power to a mating connector plug when actuated by a switch integral with the socket. The switch can be actuated by insertion of the connector plug, by pivoting open a socket cover, by sliding a slide cover into an operational position, or by a combination of the above. The switch is isolated from the power supplied to the socket and acts as a power supply signal to enable socket power. The socket is powered only when needed as indicated by the actuation method, thereby reducing draw on a power supply connected to the socket. The switch actuation methods described also provide safety features by disabling power to the socket unless the socket is actually in use. The socket cover and slide cover also prevent access to the socket unless positioned to receive a connector.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to a power socket with a switch for enabling power supply to the socket. More specifically, the present invention is related to a power socket that can be enabled using switches that are isolated from socket power, and actuated by some type of user intervention.  
           [0003]    2. Description of the Related Prior Art  
           [0004]    Power sockets that provide activation/de-activation switching of the power supplied to the socket are known in the art. For example, switched sockets are known that activate/de-activate a power socket based on safety criteria. U.S. Pat. No. 5,865,635 to Hsiang et al. is representative of this type of socket, in which power is supplied to the socket only upon insertion of a mating connector plug. The prongs of the mating connector plug activate contacts within the socket that provide power to the various legs of the plug prongs inserted into the power socket. Each prong of the inserted mating plug activates a contact which enables power to another prong of the mating connector socket. This arrangement provides a safety feature, whereby an object inserted into one of the socket receptacles will not cause that receptacle to be powered, thereby reducing the possibility of electric shock.  
           [0005]    Other known socket configurations include that represented by U.S. Pat. No. 5,374,199 to Chung, in which a power socket is activated only upon activation of a plunger type mechanism, which closes contacts within a socket to provide power to the inserted prongs of the mating connector plug. This feature provides a safety and security feature, because the socket remains unpowered until an appropriately configured mating connector plug is inserted into the socket.  
           [0006]    Similarly, U.S. Pat. No. 5,984,700 to Chang discloses a socket which remains unpowered until a mating connected plug is fully inserted and rotated 90 degrees. The mating connector plug only receives power once it has been inserted into the socket and rotated 90 degrees, upon which contacts within the socket are closed to provide power to the various socket terminals. In addition, once the mating connector plug is inserted and rotated 90 degrees in the socket, the mating connector plug is secured within the socket, thereby providing a feature which prevents the unintentional disconnection of the socket and plug once power is being supplied.  
           [0007]    Finally, U.S. Pat. No. 3,781,495 to Splingaerd shows a socket provided with an access cover, which disconnects power to the socket once it is pivoted away from the socket receptacle. The pivoted socket cover interrupts power to at least one leg of the connector socket, which interrupts the power supply to the mating connector plug. In addition, since the socket cover prevents access to the socket unless it is pivoted open, the cover acts as a safety shut-off, useful for devices drawing power from the socket, in addition to preventing potential harm to an individual accessing the socket.  
           [0008]    In all of the above disclosures, the actuating switches that provide power to the socket receptacles also carry socket power. That is, the switching elements are typically contacts which conduct power to a particular terminal of the socket once actuated. The devices of the prior art typically do not disable power to a socket completely, nor do they control switching of the power source that provides power to the socket. Moreover, the prior art does not show any way of determining whether the socket is powered based on simple visual observation.  
           [0009]    The present invention overcomes the drawbacks of the prior art by providing a switched power socket in which the switching signal can be isolated from socket power. The present invention further provides an indication of whether the socket is powered. Furthermore, the present invention provides several safety features which help to ensure safe and proper operation of the socket.  
         SUMMARY OF THE INVENTION  
         [0010]    Briefly stated, a socket provides power to a mating connector plug when actuated by a switch integral with the socket. The switch can be actuated by user action, including, e.g., inserting a connector plug, pivoting open a socket cover, sliding a slide cover into an operational position, or a combination of the above. The switch is isolated from the power supplied to the socket and acts as a power supply signal to enable socket power. The socket is powered only when needed as indicated by the actuation method, thereby reducing draw on a power supply connected to the socket. The switch actuation methods described also provide safety features by disabling power to the socket unless the socket is actually in use. The socket cover and slide cover also prevent access to the socket unless positioned to receive a connector.  
           [0011]    According to an embodiment of the present invention, there is provided a socket for providing electrical power, comprising: a housing having an inner chamber, at least one electrically conductive terminal in the inner chamber, the at least one terminal being connectable to an electric power source, the at least one terminal being accessible through an opening in a wall of the housing to supply electric power from the power source to a connector insertable through the opening, a socket enable switch operable to permit application of the electric power to the at least one terminal and the socket enable switch being isolated from the electric power.  
           [0012]    According to another embodiment of the present invention, there is provided a socket for providing electrical power, comprising: a housing having an inner chamber, at least one electrically conductive terminal in the inner chamber, the at least one terminal being connectable to an electric power source, the at least one terminal being accessible through an opening in a wall of the housing to supply electric power from the power source to a connector insertable through the opening, an opening cover positionable in at least a first and a second position, the opening cover permitting access to the at least one terminal through the opening when in the first position, the opening cover preventing access to the at least one terminal through the opening when in the second position and a socket enable switch operable to permit application of the electric power to the at least one terminal when the opening cover is in the first position.  
           [0013]    According to another embodiment of the present invention, there is provided a method for controlling power supplied to a socket, comprising: providing a switch operable to permit application of electric power from an electric power source to a socket terminal, actuating the switch by at least one of: inserting a mating connector into the socket, pivoting a cover on the socket and sliding a slide cover on the socket; wherein the switch is isolated from the electric power. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which:  
         [0015]    FIGS.  1 ( a ), ( b ) and ( c ) are various perspective views of the power socket according to the present invention;  
         [0016]    [0016]FIG. 2 is a cross sectional perspective view of the power socket according to the present invention;  
         [0017]    [0017]FIG. 3 is a cross sectional perspective view of a first embodiment according to the present invention;  
         [0018]    [0018]FIG. 4 is a perspective view of a second embodiment according to the present invention;  
         [0019]    [0019]FIG. 5 is a cross sectional perspective view of the embodiment of FIG. 4;  
         [0020]    [0020]FIG. 6 is a perspective view of a third embodiment according to the present invention; and  
         [0021]    FIGS.  7 ( a ) and ( b ) are cross sectional perspective views of the embodiment of FIG. 6;  
         [0022]    FIGS.  8 ( a ) and ( b ) are cross sectional perspective views of a combination of embodiments according to the present invention;  
         [0023]    [0023]FIG. 9 is a perspective view of an embodiment of the present invention in a partially assembled state; and  
         [0024]    FIGS.  10 ( a ) and ( b ) are circuit schematics showing possible configurations of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    Referring now to FIGS.  1 ( a ), ( b ) and ( c ), a socket  10  according to the invention is shown. FIG. 1( a ) shows a lower exterior surface of socket  10  including plugs  12 ,  14 . Preferably, plug  12  provides a connection for socket power, while plug  14  provides an electrical connection for a socket switch capable of enabling/disabling socket power.  
         [0026]    A cover  16  is arranged on socket  10  to prevent or permit access to plug receptacles  30 ,  32  and  34 , shown in FIG. 1( c ). Cover  16  is attached to socket  10  with hinges  36 ,  38 , which allow cover  16  to pivot open and close, to permit or prevent access to plug receptacles  30 ,  32  and  34 , respectively. Hinge  38  preferably has a spring  42 , which engages socket  10  and cover  16  to urge cover  16  into a closed position, as illustrated in FIG. 1( b ).  
         [0027]    Referring to FIGS.  1  ( c ) and  2 , a socket power indicator cover  40  is located on a top surface of socket  10 , and transfers a light indication when power is applied to the power terminals accessible through plug  12 . Indicator cover  40  preferably transfers light from a lamp or an LED, such as LED  68 . LED  68  is connected across power terminals within plug receptacles  30  and  32 , for example, through an appropriate limiting resistance. Indicator cover  40  provides a simple visual indication that power is supplied to socket  10 .  
         [0028]    Referring now to FIG. 3, a switch  18  is mounted in socket  10 . Switch  18  is sized so as to be positioned between a terminal, e.g., a hot terminal  44 , and an internal surface of socket  10 . Switch  18  includes a switch hinge  20  that can pivot to provide internal contact connection/disconnection (not shown). Hinge  20  is connected to a preferably insulated switch lever  26 , which rotates about hinge  20  and can actuate internal contacts within switch  18 . Lever  26  is urged toward hot terminal  44 , which permits the internal contacts within switch  18  to be in an open state in the absence of a connector plug prong inserted into hot terminal  44 . A resilient member (not shown) within switch  18  provides a pre-loaded force, for example, to urge lever  26  towards hot terminal  44 . Switch hinge  20  can alternatively provide a force against lever  26  through a pre-loaded member such as a spring, or other resilient member, for example.  
         [0029]    The internal contacts within switch  18  are connected to two switch terminals  48 , which are housed within plug  14 . Upon actuation, switch  18  causes a contact to be made between switch terminals  48 , to complete an electrical circuit through switch terminals  48  extending through plug  14 .  
         [0030]    A neutral terminal  46  and hot terminal  44  have connection leads that extend through plug  12 . Hot terminal  44  and neutral terminal  46  are shaped to receive connecting prongs of a mating connector plug inserted through plug receptacles  30  and  32 , respectively. By receiving the connecting prongs of a mating connector plug, hot terminal  44  and neutral terminal  46  provide an electrical connection to the connecting prongs, and are thus capable of supplying power to the mating connector plug and any device to which the plug is connected.  
         [0031]    Referring for a moment to FIGS.  8 ( a ) and ( b ), the above described embodiment of the present invention is optionally arranged in a number of variations. For example, socket  10  may contain several switches, such as switches  63 ,  65  arranged adjacent to various portions of both hot terminal  44  and neutral terminal  46 . Optionally, a switch similar to switch  18  can be arranged adjacent to ground plug receptacle  34 , alone or in combination with switches  63 ,  65  arranged adjacent to terminals  44 ,  46 . The switches  63 ,  65  can be arranged in series, so that each switch  63 ,  65  must be closed before power is permitted to flow to socket  10 . While switches  63 ,  65  are shown as being connected independently of hot terminal  44  and neutral terminal  46  in FIGS.  8 ( a ) and ( b ), switches  63 ,  65  can also be used to directly switch and conduct electrical power to hot terminal  44  or neutral terminal  46 , provided they are constructed to have appropriate current and voltage ratings.  
         [0032]    Referring again to FIG. 3, socket  10  operates to provide switched electrical power when a mating connecting plug is inserted into plug receptacles  30 ,  32  and  34 . It should be readily observed that socket  10  can be configured to operate and provide switched electrical power when one or more prongs of a mating connector plug are inserted into any of plug receptacles  30 ,  32  or  34 . Socket  10  is operated by first pivoting cover  16  into an open position in which plug receptacles  30 ,  32  and  34  are exposed for access. A mating connector plug is then inserted into socket  10 , with prongs of the mating connector plug being preferably shape fitted to match the openings defined by plug receptacles  30 ,  32  and  34 . The shape of plug receptacles  30 ,  32  and  34  prevent insertion of a mating connector plug unless properly oriented. Upon insertion into plug receptacles  30 ,  32 , the prongs of the mating connector plug contact and slide along terminals  44 ,  46 , forming an electrical connection between the prongs and terminals  44 ,  46 . When further inserted into receptacles  30 ,  32 , at least one prong contacts and urges switch lever  26  in a direction away from terminal  44 . As the mating connector plug is fully inserted into socket  10 , at least one connector prong fully engages switch lever  26  to actuate switch  18 , thereby closing the internal contacts of switch  18 . Upon closure of the internal contacts within switch  18 , an electrical circuit is completed through switch terminals  48 , which signals a power supply to provide electrical power to terminals  44 ,  46 . As the power supply provides power to terminals  44 ,  46 , LED  68  is energized providing light to indicator cover  40 , which in turn provides a visual indication that socket  10  is live and capable of providing power.  
         [0033]    Referring momentarily to FIGS.  10 ( a ) and ( b ), configurations of possible circuits incorporating the present invention are shown. Plug  12  of socket  10  in FIG. 10( a ) is connected to the output of a power inverter  70 , for example, an inverter converting a D.C. voltage to A.C., such as 12V D.C. to 120V A.C. Plug  14  is connected to a relay coil  72  with normally open contacts  74  that enables input power to be delivered to inverter  70 . When a switch, such as switch  18 ,  63  or  65  of power socket  10 , is closed by user action as described above, relay coil  72  is energized and contacts  74  are moved to a closed state. Once contacts  74  are closed, power is supplied to the input of inverter  70 .  
         [0034]    The circuit shown in FIG. 10( b ) has the connections to plugs  12  and  14  wired in series. In this configuration, power is always supplied to inverter  70 , and the power output of inverter  70  is always available. The output of inverter  70  is switched at socket  10  through plug  14 . For example, a switch in a configuration similar to switches  18 ,  63  or  65  is arranged to cooperate with plug  14  to switch socket power upon user action. Power is permitted to flow through plug  14  to plug  12 , and supply a connector plug with power from inverter  70 . In an alternate embodiment, plug  14  may not be provided. In this alternate embodiment, switch(es)  18 ,  63  and/or  65  independently of socket  10  switch power to the socket terminals upon user actuation. Although a DC-AC power inverter supplied with power from a storage battery is shown, any electrical power source, for example an A.C. main source, a D.C. source, etc., can provide power to socket  10 . In these embodiments, the socket internal switch(es)  18 ,  63  and/or  65  is not isolated from the output of the electrical power source.  
         [0035]    Referring now to FIGS. 4 and 5, a further embodiment of the present invention is shown. In FIGS. 4 and 5, reference designators having the same numeral designation as provided in FIGS.  1 - 3  indicate like elements, and a description thereof is omitted.  
         [0036]    According to the features of this embodiment, FIGS.  4 - 5  show a cover switch post  50  attached to an inner surface of cover  16 . Cover switch post  50  is positioned on the inner surface of cover  16  to be in pivotal alignment and cooperation with a switch opening  54  positioned on a top face of socket  10 . Switch opening  54  permits access to a switch plunger  52  that is connected to switch  22  shown in FIG. 5. A force is preferably applied to normally urge switch plunger  52  generally toward cover  16  to keep the switch closed. The force is applied through, for example, a pre-loaded spring or resilient member connected to switch  22 . When switch plunger  52  is in a non-depressed state, internal contacts (not shown) within switch  22  are closed to provide an electrical path between switch terminals  48 .  
         [0037]    Operation of socket  10  shown in FIGS.  4 - 5  is controlled by cover  16 . When cover  16  is in a closed state, i.e., covering the top surface of socket  10 , socket  10  remains unpowered. In the unpowered state, cover switch post  50  projects into switch opening  54  and contacts switch plunger  52 . When cover switch post  50  contacts switch plunger  52  as cover  16  is pivoted closed, switch plunger  52  is depressed, forcing the internal contacts within switch  22  into an open state. When the internal contacts within switch  22  are placed in an open state, the electrical connection between terminals  48  is opened, and the power supply to socket  10  is cut off. When the power supply is cut off, terminals  44 ,  46  are unpowered. Without power supplied to terminals  44 ,  46 , LED  68  is deenergized, thus removing the light source to indicator cover  40  thereby indicating that socket  10  is de-powered.  
         [0038]    When cover  16  is pivoted open, cover switch post  50  releases switch plunger  52  from a depressed position. A resilient member within switch  22  urges switch plunger  52  into an up position, generally towards cover  16 . When switch plunger  52  is no longer depressed, internal contacts within switch  22  are connected, providing an electrical connection between switch terminals  48 . When switch terminals  48  are connected, a power supply to socket  10  is turned on, and power is supplied to terminals  44 ,  46 . Once terminals  44 ,  46  are powered, LED  68  is energized, providing a light source to indicator cover  40  which provides a visual indication that socket  10  is powered.  
         [0039]    Spring  42  connected to hinge  38  normally urges cover  16  into a closed position. Accordingly, cover switch post  50  engages and depresses switch plunger  52  in a normal de-activated state. Cover  16  in combination with cover switch post  50  provide a default fail safe configuration in this arrangement.  
         [0040]    A combination of the embodiments shown in FIGS.  1 - 3  and FIGS.  4 - 5  may also be provided. In such an arrangement cover  16  actuates a first switch  22  and the prong or prongs of the mating plug to be connected to socket  10  actuate at least one other switch, i.e., switch  18  as in FIGS.  1 - 3  while the plug is inserted. The two switches can be coupled in series so that power can be applied to the terminals  44  and  46  only if both the cover is opened and the plug is inserted.  
         [0041]    Referring now to FIG. 6, another embodiment of the present invention is shown. In this embodiment, socket  10  is equipped with a slide cover  24 , which includes two openings  56 ,  58 . Openings  56 ,  58  have substantially the same shape dimension as plug receptacles  30  and  32 , respectively. Slide cover  24  is slidable in a lateral direction along the top surface of socket  10 . In a fully extended position, an outer edge  60  of slide cover  24  is flush with an edge of the top surface of socket  10 . In this position, openings  56 ,  58  are unaligned with receptacles  30 ,  32 , thereby preventing access to terminals  44 ,  46 . Referring for a moment to FIG. 9, slide cover  24  cooperates with resilient members, such as springs  76  which urge slide cover  24  into the extended position shown in FIG. 6.  
         [0042]    Slide cover  24  can be slid into an operating position by the application of a lateral force to outer edge  60  to overcome the urging force of springs  76 . When slide cover  24  is thus placed into operating position, openings  56 ,  58  align with receptacles  30 ,  32 , respectively. Aligned openings  56 ,  58  and receptacles  30 ,  32  permit access to terminals  44 ,  46 , respectively. Once slide cover  24  is placed in the operating position, the prongs of a mating connector plug may be inserted into receptacles  30  and  32 , to contact terminals  44 ,  46 , and slide cover  24  thereby remains in the operating position.  
         [0043]    Referring now to FIGS.  7 ( a ) and ( b ), a switch  62  is positioned adjacent slide cover  24 . FIG. 7( a ) shows a cross-sectional view of socket  10 , while FIG. 7( b ) shows a cross-sectional view of socket  10  including hinges  36 ,  38  for reference points. Switch  62  is equipped with a switch plunger  64 , which cooperatively engages a sloped portion  66  located on a lower side of slide cover  24 . Switch plunger  64  operates a set of internal contacts (not shown) within switch  62  when actuated. In a normal, non-operative state, slide cover  24  is in a position in which outer edge  60  is flush with an edge of the top surface of socket  10 . In this state, sloped portion  66  permits switch plunger  64  to extend away from switch  62  in a non-depressed state. Switch plunger  64  is urged upward generally towards the top surface of socket  10  by a resilient member (not shown) within switch  62 . When switch plunger  64  is in a raised, or non-depressed state, the internal contacts within switch  62  are separated, and switched terminals  48  remain electrically disconnected.  
         [0044]    When slide cover  24  is placed in a normal operative state, sloped portion  66  slides along and gradually depresses switch plunger  64  as slide cover  24  is slid into an operating position. As switch plunger  64  is depressed, the internal contacts within switch  62  are closed, thus providing an electrical connection between switch terminals  48 .  
         [0045]    Operation of the various embodiments shown in FIGS.  6 - 9  is explained with the embodiment shown in FIG. 6. Socket  10  is unpowered with cover  16  in a closed position prior to insertion of a mating connector plug. Socket  10  is operated by first pivoting cover  16  into an open position to permit access to slide cover  24 . Slide cover  24  is then slid into an operating position by the application of lateral force to outer edge  60 , whereby openings  56 ,  58  align with receptacles  30 ,  32 , respectively. As slide cover  24  is being slid into an operating position, sloped portion  66  slides along and depresses switch plunger  64 , causing the internal contacts within switch  62  to become closed. Thus, as slide cover  24  is placed in the operational position, terminals  48  are electrically connected and activate the power supply or otherwise allow power to be applied to socket  10 . As the power supply is activated, or power is otherwise supplied to terminals  44 ,  46 , socket  10  becomes powered. Once terminals  44 ,  46  are powered, LED  68  is energized and provides a visual indication of socket power through indicator cover  40 .  
         [0046]    Socket  10  is now ready to receive and power an inserted mating connector plug. Once inserted, the mating connector plug prevents slide cover  24  from moving to a non-operational state. The mating connector plug can be easily removed, causing socket  10  to be de-powered due to springs  76  urging slide cover  24  into a non-operational, de-powered state. The removal of a mating connector plug permits slide cover  24  to automatically slide into the extended position with outer edge  60  flush to an edge of the top surface of socket  10 . As slide cover  24  slides into the extended position, slope portion  66  disengages and releases switch plunger  64 . As switch plunger  64  is released, the internal contacts within switch  62  are opened, thus breaking the electrical connection between terminals  48 . Once the electrical connection between terminals  48  is broken, the power supplied to socket  10  is removed and socket  10  is de-powered. Thus, the removal of a mating connector plug from socket  10  disables power and prevents access to receptacles  30 ,  32 . In this default, non-operative state, socket  10  is placed in a fail safe condition.  
         [0047]    While various embodiments of the present invention have been described, it should be evident that the embodiments can be selectively combined to produce further embodiments without departing from the scope of the subject matter provided in the present description. For example, socket  10  having a slide cover  24  with corresponding switch  62  can be combined with the embodiment in which switches  18 ,  63 ,  65  are provided adjacent respective terminals  44 ,  46 . Alternatively, mechanical linkages may be used to activate the various switches upon the cover being pivoted, the slide cover being slid or a mating plug being inserted. In addition, a user may activate socket  10  with other switching methods accessible to the user. For example, a magnetic or push-button switch may be used to activate socket  10  by user action. Thus, the scope of the invention should not be limited by specific embodiments disclosed, as many possible variations of the present invention are possible through a combination of various features disclosed.  
         [0048]    The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.