1. Field of the Invention
The present invention relates to electrical plugs and sockets for connecting and disconnecting electronic devices.
2. Description of the Related Art
A plug and socket are mating electrical connectors used to supply electrical power to an electronic device, such as a computer or home appliance. An electrical plug is typically a male electrical connector included with the electronic device that removably “plugs into” a female socket to receive electrical power from the socket, such as in the form of alternating current (AC) or, less commonly, direct current (DC). Terminals on the plug (i.e. “plug terminals”) mate with terminals on the socket (i.e. “socket terminals”) when plugged in. Plug terminals are usually male, and male plug terminals may be pins, prongs, blades, or combinations thereof. A plug with male terminals mates with a socket having a corresponding arrangement of female terminals. When the plug terminals are inserted into the socket holes, the plug terminals are placed in electrical contact with electrical “socket terminals” within the electrical socket. The socket terminals on a female socket may be referred to herein as female terminals, because these terminals are associated with the holes of the socket, even though the terminals may not themselves form a female socket. Though the male plug is generally fixed to an electrical device or appliance and the female socket is typically fixed, such as being secured to a wall, the reverse configuration is also possible.
An electrical socket is energized with electricity, such as from a commercial power supply or electrical generator, so that electric power can flow from the socket to an electronic device plugged into the socket. The electrical socket may be a “wall socket” included within a wall outlet of a building, for example. Other devices, such as PC battery-backup devices and power strips, plug into an electrical socket such as a wall socket, and include multiple on-board electrical sockets that receive electrical power from the wall socket. Yet another type of electrical socket may be included directly on an electronic device for daisy-chaining with additional electronic devices. For example, in a component stereo system, a primary audio component such as an audio receiver may include both a plug for plugging-into and receiving power from a wall socket or power strip, and one or more on-board electrical sockets that are wired to transfer some of the current from the wall socket or power strip to additional audio components plugged directly into the on-board electrical sockets. Other configurations of electrical sockets and mating electrical plugs are also known in the art.
One drawback of conventional plugs and sockets is the risk of exposure of the user to electrical shock, especially while the user plugs-in (connects) or un-plugs (disconnects) an electronic device. In particular, the plug terminals on a male plug typically extend directly from a plug body that the user grasps when plugging-in the device. Thus, the male plug terminals are typically exposed, and the user's fingers can be dangerously close to the male plug terminals when holding the plug body. When the electronic device is plugged in, the plug terminals contact the socket terminals prior to full insertion of the plug terminals into the socket holes. Likewise, when the electronic device is unplugged, the plug terminals may remain in electrical contact with the socket terminals until the plug terminals have been nearly fully removed from the socket holes. Thus, the plug terminals are energized for at least a portion of the movement of the plug with respect to the socket when either plugging-in or un-plugging an electronic device. The user risks electrical shock by inadvertently contacting the plug terminals with the user's fingers while the user is plugging-in or unplugging the electronic device.
The complications of conventional plugs and sockets are compounded in the case of power strips, which are usually loose rather than being fixed to any particular surface. Thus, to unplug an electronic device from a power strip, the user must usually hold the power strip while removing the plug. The tendency is for the user to hold the power strip with one hand while pulling on the plug with the other hand. This maneuver places both hands in potentially-dangerous proximity to electrically energized plug terminals of the device being unplugged, to electrically energized plug terminals of another device, or to open female socket terminals. Aside from the risk of shock, the process of removing a plug from a power strip may be cumbersome, as well. If the power strip is placed under a desk or other location with limited access and/or limited lighting, it can be difficult for the user to access the power strip with both hands. Some users might even be tempted to step on an edge of the power strip to hold it while pulling out the plug, which is also not ideal.
A solution is desired for improved connection of an electronic device to an electrical socket, particularly in view of the above limitations in the prior art plugs and sockets. For example, an apparatus that makes plugging-in and un-plugging a device easier and/or safer is desired. It would be advantageous if such a solution did not require any direct redesign of the electronic device, so that, for example, an electronic device having a conventional plug could still be coupled to and powered by an electrical socket using the proposed solution.
One embodiment provides a coupling for connecting and disconnecting an electrical plug and an electrical socket. A sleeve is slidably disposed on a first end of a coupling body. One or more male terminals on the first end of the coupling body are disposed within the sleeve and are configured for insertion into the electrical socket. A plug cavity at a second end of the coupling body is configured for receiving an electronic device plug. One or more interior electrical contacts are disposed within the coupling body in electrical communication with the one or more male terminals, and are configured for electrically contacting one or more plug terminals of the electronic device plug. The sleeve and coupling body are movable axially with respect to each other between a prong-extended position having the one or more male terminals on the coupling body extending out of the sleeve, and a prong-retracted position having the one or more male terminals substantially received within the sleeve. At least one release member is secured to the sleeve and to the coupling body. The at least one release member is movable to cause the sleeve and the coupling body to move with respect to each other from the prong-extended position to the prong-retracted position.
Other embodiments, aspects, and advantages of the invention will be apparent from the following description and the appended claims.
The present invention includes an apparatus that allows an electronic device to be safely and easily connected to and disconnected from an electrical power outlet. An apparatus according to the invention may be used to safely and easily connect an electronic device having a conventional plug to an electrical socket. The apparatus also allows the electronic device to be safely and easily unplugged from the electrical socket using only one hand. One-handed operation is possible even in the case of a power strip that is not secured in place. The risk of electrical shock is minimized because the terminals on the plug of the electronic device are shielded from the user's fingers as the device is plugged-in or unplugged, making it difficult or impossible for a user to contact live electrical terminals by hand.
One embodiment of the invention provides a coupling for connecting the electronic device to the electrical socket. The coupling includes a coupling body and a sleeve slidably disposed on a distal end of the coupling body. An arrangement of male terminals disposed on the distal end of the coupling body are configured for insertion into a corresponding arrangement of female terminals on the electrical socket. The plug of the electronic device is inserted into a proximal end of the coupling body, placing the plug terminals in communication with a plurality of interior electrical contacts disposed within the coupling body. The interior electrical contacts are internally connected to the male terminals at the distal end of the coupling body via electrical conductors disposed in the coupling body. Thus, the coupling mechanically and electronically connects the electronic device to the electrical socket. The proximal end of the coupling optionally includes a plug cavity having cavity walls that encircle the plug of the electronic device, particularly for preventing the user from contacting the prongs of the plug with the user's fingers once the prongs are in contact with the interior electrical contacts disposed within the coupling body. This is one of several aspects that enhance the safety of plugging-in and unplugging the electronic device by minimizing the likelihood of electrical shock.
The sleeve and coupling body are axially movable with respect to each other from a prong-extended position, wherein the male terminals on the coupling body extend out of the sleeve (where they can be plugged into the electrical socket), to a prong-retracted position, wherein the male terminals are substantially fully received within the sleeve. A release mechanism comprising at least one release member is secured to the sleeve and to the coupling body. The at least one release member is movable to cause the sleeve and coupling body to move with respect to each other from the prong-extended position to the prong-retracted position. This movement causes the male prongs to retract from the electrical socket, and can easily be performed with one hand, even when the coupling is plugged into an unsecured power strip or other power outlet.
A pair of opposing, outwardly-bowed release members 50A and 50B are coupled at one end to the sleeve 20 and at the other end to the coupling body 40. The release members 50A, 50B collectively constitute one exemplary embodiment of a “release mechanism,” generally indicated at 50. The release members 50A, 50B are, in this embodiment, flexible plastic that, when in a relaxed state, bias the coupling 10 to the relative position of the sleeve 20 and coupling body 40 shown in
The female terminals 47A-C are shown as having a generally female, U-shaped cross-section as shown, so that when male plug terminals are inserted into the socket holes 44A-C, those plug terminals will be in electrical contact with the female terminals 47A-C throughout a range of movement of insertion. Alternatively, however, the female terminals 47A-C could be given a flat, or otherwise substantially non-female cross-sectional shape, so that male plug terminals only make contact with the female terminals 47A-C when partially or fully inserted into the socket holes 44A-C. However, such an alternative, flat configuration of the terminals 47A-C would still be considered “female” in the context of this disclosure, due to the socket holes 44A-C that are predisposed to guiding male plug terminals into engagement with the terminals 47A-C. Cavity walls 45 partially surround the plug, providing a physical barrier between the plug and a user's fingers, to protect the user from potential shock.
In the exemplary embodiment illustrated, the same three-terminal arrangement (e.g. three male plug terminals and three female socket terminals) is consistently used throughout to carry electrical power from the wall outlet 90 to the power strip 80, from the power strip 80 to the coupling 10, and from the coupling 10 to the receiver 60. This three-terminal arrangement is just one of many different configurations that may be selected. In this example, one of the three terminals in each three-terminal arrangement may be the “live contact,” e.g. male terminals 64A, 48A, 84A and female terminals 47A, 88A, and 94A. Another of the three male terminals in each three-terminal arrangement may be the “neutral contact,” e.g. male terminals 64B, 48B, 84B and female terminals 47B, 88B, and 94B. The third of the three terminals in each three-terminal arrangement may be an optional “ground contact,” e.g. male terminals 64C, 48C, 84C and female terminals 47C, 88C, and 94C. The live contact (alternatively referred to as phase, hot, or active), along with the neutral contact, carries power from the power source (e.g. from the wall outlet 90) to the downstream component, e.g. to the power strip 80, coupling 10, and ultimately, to the device 60. The voltage between the live and neutral contacts typically varies by country, as set by national standards.
In some installations, there may be two live conductors, either being two phases from a three-phase system or being both phases from a split-phase system. As in the example of
The neutral contact, along with a live contact, completes the circuit between the power source and equipment. The neutral contact may be chosen as the zero voltage reference point, with the live contact's voltage measured with respect to it. In many cases, local electrical regulations require the neutral contact to be connected to earth/ground. In such systems, even though the neutral conductor is at a very low voltage with respect to the ground, it is insulated for the full supply voltage in case of a fault, such as a break in the wiring between neutral and source.
The ground contact (sometimes referred to as the “earth” contact) is generally intended to carry electric current when connected to equipment that has developed an insulation fault. The ground connection was added to modern plugs because, if a live wire or other component in a device touches the metal casing, anybody touching the device may receive a dangerous electric shock. In many countries devices with metal cases must have the case connected to the ground contact. This reduces but does not eliminate the possibility of the case developing a high voltage relative to the ground and grounded metalwork.
To plug in the coupling 10 to the power strip 80, the user may grasp the coupling body 40, and then plug in the coupling 10 to the AC socket 82 in the power strip 80. Grasping the coupling body 40 near the proximate end 14 is convenient for the user, because the proximate end 14 is generally closer to the user's hand as the user is plugging the coupling 10 into the power strip 80. Grasping the coupling 10 by the coupling body 40 will help ensure that the male terminals 48A-C are fully inserted into the AC socket 82, because the male terminals 48A-C are rigidly secured to the coupling body 40 in this embodiment. It may also be possible to plug the coupling 10 into the on-board AC socket 82 while grasping the sleeve 20, depending on the rigidity of the release members 50A, 50B and the tightness of the fit of the male terminals 48A-C with the socket holes of the on-board AC socket 82. However, if the fit between the male terminals 48A-C and the AC socket 82 is sufficiently snug, and/or if the release members 50A, 50B are sufficiently flexible, then grasping the coupling 10 by the sleeve 20 when plugging-in the coupling 10 may instead cause the release members 50A, 50B to simply flex inwardly and the male terminals 48-C to retract at least partially into the sleeve 20, rather than being fully inserted into the AC socket 82. Some manufacturers may even prefer this aspect for safety, to discourage plugging-in the coupling 10 while holding the sleeve 20 that will be nearer to the live on-board AC socket 82.
With the plug 63 fully inserted into the cavity 42 and the coupling 10 fully inserted into the AC socket 82, electric power may be transferred from the power strip to the electronic device 60 (
As previously indicated, many different plug/socket arrangements may be used with the invention.
The terms “comprising,” “including,” and “having,” as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms “a,” “an,” and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The term “one” or “single” may be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as “two,” may be used when a specific number of things is intended. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having 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. Accordingly, the scope of the invention should be limited only by the attached claims.
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