Patent Application
20180090870
The current invention relates to field of electrical adapters with receptacles on one side and a plug on the other. Such adapters are common as travel plug adapters where the receptacles are designed to accept plugs designed for one market, e.g., UK or Europe and plug into a wall socket of another market, e.g. US. The current invention plugs into a regular wall socket with or without a ground pin and turns it to a Tamper Resistant Outlet (TRO)
In recent years, an increasing number of States in USA have adopted 2008NEC (National Electrical Code) standard which requires use of Tamper Proof Outlet (TRO) in new buildings. These outlets have a plastic (or other electrically insulating material) screen covering the Live and Neutral outlets to protect against children inserting metal objects in powered outlet. When a plug is inserted in a tamper resistant socket, it would push against a spring loaded mechanism that pulls the screen down thus allowing the insertion of the Live and Neutral blades. When the plug is pulled, as soon as the blades disengage from their outlets, the screen jumps back up.
Customers will have to replace their existing wall sockets with a TRO and while such sockets are not expensive, replacing existing wall sockets is not always straightforward. Customers will have to turn the power off, remove the old socket and wire the new TR socket correctly.
The prior art in this field as depicted in the patents referenced above can be divided into three categories: One the deals with design of and construction of the mechanism inside the wall socket to make it tamper resistant teaching different methods for such implementation. Not surprisingly these patents were assigned to major socket manufacturers such as Leviton and Hubble. The second category is one where the patents pertain to covers of wall sockets to make them tamper resistant. The third category is for patents pertaining to socket plug locked combination to prevent separation if the plug is yanked but prevent partial disengagement thereby exposing live conductors.
The invention consists of an electrical adapter with plastic or electrically insulator material body and a TRO socket on one side and a NEMA 5 or NEMA 1 plug on the other side. The blades of the NEMA 1 or 5 are electrically coupled to the corresponding receptacles of the TRO socket. When it is plugged, it covers the original wall socket and what is exposed to the user is the tamper resistant outlets. This can be done in several ways; but can be divided into two approaches; one is to design and manufacture a TRO adapter from scratch or modify the design of an existing TR socket to incorporate a plug. The other is to incorporate an off the shelf tamper resistant wall socket in making the adapter.
The former involves designing a new receptacle/plug bar parts and a new enclosure. The latter uses existing TRO wall sockets and electrically connects its terminals to the corresponding bars and pins of a plug. Such connections can be direct or using a printed circuit board or any other conducting surface. In both cases there two ways for implementation; one where both sets of pins of the plug are used which, while electrically redundant, gives the adapter better anchoring in the wall socket, or only one set and electrically connect the corresponding outlets internally.
FIG. (1) shows the metal stamped piece of the socket inlet-plug bar. Folding part (2) 180 degrees out of the page along line (A), then its top part is folded out of the page less than 90 degrees at the base of notch (3) and along line (B) to form a lip (1). Both inlets are connected by and electrically conductive strip (7), so if either inlet is powered the other would be powered too. The plug bar is formed by folding the bottom part (5) 180 degrees out of the page onto the top part (4). The holes (6) are optional and not required by the standard.
FIG. (2) shows the resulting inlet-plug combination after folding and optionally riveting the bottom part (5) to the top part (4) with a rivet (8). The connecting strip (7) electrically connects two inlets for plug bars. FIG. (2) shows the resulting plug bar (9) and the two inlets.
FIG. (6) shows a duplex NEMA 1 (28) ungrounded wall socket with Live outlets (23) and Neutral outlets (24) and a screw (25) to attach the face plate (not shown).
FIG. (7) shows front and side views of the grounding metal piece (27) with a screw hole (26).
FIG. (9) shows the bottom or plug part (29) of an adapter for NEMA 1 wall socket, it shows the Live (18) and Neutral (17) bars and a depression (30) deep enough to enclose the screw (25) and grounding piece (27) and grounding inlet (31) which may also be circular.
FIG. (10) shows the metal bracket (32) that houses the Earth outlets (33) and secures the socket to the wall and secures the face plate with a screw through a screw hole (34).
FIG. (11) shows the plastic part of the bottom of a wall socket (35) and bottom pars underneath the Earth metal bracket (36) and underneath the live outlet (37).
FIG. (12) shows the top part of TRO (13) and screw hole for the wall plate (38).
The invention is a duplex (2 gang) tamper resistant socket adapter pluggable into a regular wall socket (NEMA 1 or NEMA 5). The plug terminals provide AC power and grounding to the socket outlets. There are basically two embodiments for realizing this invention; each, however, has multiple implementations. For each there are the cases of NEMA 5 (grounded) wall sockets and NEMA 1 (ungrounded wall sockets).
The first embodiment is to design a new, or modify the design of an existing, tamper resistant socket to make it pluggable into regular wall socket. This entails creation of new socket outlets/inlets-plug bar combinations, modifications to plastic enclosure to accommodate the plug bars and their interconnection to the socket outlets. One example of socket outlet-plug bar combination is shown in FIG. (2), the bottom of the plastic housing of the socket is cut to allow the bar through as shown in FIG. (11). Holes are also drilled in the bottom of the plastic housing of the socket to allow for Earth pins of the plug, whether one or two Earth pins are used. In both cases an electrically conducting screw through the screw hole (36) of FIG. (10) driven all the way to the connecting strip (11) of FIGS. (3A & 3B) which also secures the said strip in place in addition to providing electrical connection between the two sets of Earth terminals; those of the socket and those of the plug. FIGS. (4A & 4B) show alternative implementations of the socket outlet-plug bar combination and may include one or more screws to secure them to the plastic body of the adapter. From electrical point of view, it does not make a difference if only one set
Of plug bars and earth pins is inserted in the wall socket or both sets as far the combinations shown in FIG. (2) and FIG. (4A), the latter, however provides better anchoring in the wall socket.
For ungrounded (NEMA 1) wall sockets, the Earth pins are replaced by a grounding metal piece (27) of FIG. (7) which is L shaped with a screw hole (26). This piece uses the screw that secures the plastic face plate to the wall socket and goes through the metal bracket (32) which houses the Earth outlets of the socket as shown in FIG. (10). The screw is first removed and the said grounding piece (27) is placed on top of the face plate and screwed in through the metal bracket thus electrically connecting the said grounding piece (27) to Earth through the said metal bracket (33). The bottom of the adapter for non grounded wall sockets shown in FIG. (9) has a depression in the middle deep enough so that when it is placed over the screw (25) and the grounding piece (27), the length of the plug bars and Earth pins engaged in the wall socket does not change and stay within NEMA standard requirements. Instead of the Earth pins, the adapter for ungrounded wall socket has a grounding contact (28) shown in FIG. (8B). The said contact extends slanted over a grounding inlet (31) shown in FIG. (9) and extending beyond the center so that when the grounding piece (27) is inserted it would push the grounding contact upward and forcing to press against the grounding piece (27) for improved electrical contact. The electrical contact with the Earth of the socket is established through the said metal screw (25), driven all the way and pressing against the connecting strip (11) that also mechanically secures it. Alternately, as shown in FIG. (12), a long metal screw though the screw hole (38) in the top part of the tamper resistant socket (13), the said through hole lines up vertically with the screw hole (34) of the metal bracket (32) in FIG. (10) and the hole (39) in the bottom part of the socket (35) shown in FIG. (13). The faceplate screw (25) is removed and the adapter is plugged into the NEMA 1 wall socket and the long screw is screwed in the metal bracket (32) of the wall socket there by electrically connecting the two Earth connections.
In this embodiment, an off the shelf tamper resistant socket is used to construct the tamper resistant adapter. The electrical connections between the outlets of the said tamper resistant socket and plug bars and pins can be established via electrically conducting metal connectors (21) in FIG. (5A) and connecting them to the plug terminals (16, 17 and 19). The said connectors (21) also serve as anchors for the said socket and can be simply a printed circuit board PCB making the connections through traces, which in turn is secured to an enclosure (14). In case of NEMA 1 ungrounded socket, can be secured to the said enclosure (21) and connected to the terminals of the tamper resistant socket (12, 15, and 22) using electrical wires without need for a PCB or any other connecting plane. Grounding is achieved using a long screw through the holes (38) and (34) and the wall socket's plate hole (after removing the screw). The said screw will provide anchoring and electrical connection between the adapter's Earth pin (15) and the metal frame of the wall socket. The said metal frame is secured to the grounded metal enclosure in the wall.
| Number | Date | Country | |
|---|---|---|---|
| 62399577 | Sep 2016 | US |
