The disclosure relates to electrical connectors for passing electrical current. More particularly, the present disclosure relates to electrical connectors that connect magnetically.
Most electrical connectors are joined by mechanical means, typically using a male/female, frictionally-fitting connection, so that they can pass an electrical current from one connector to the next. Mechanical connectors require manual effort to join. Connectors that use magnetism rather than a mechanical connection are known. The magnetic force may be used to join the two connectors rather than manual effort. U.S. Pat. No. 8,936,472, which is incorporated herein in its entirety by reference and which is owned by the present applicant, discloses such a connector. Magnetic connectors are useful in circumstances where the two connectors cannot be easily joined by manual effort.
One example of circumstances in which access to couple two connectors is limited is in artificial holiday trees. Electrical current is passed by conductors via tubes or poles that simulate the trunk of an evergreen tree. Existing pole construction for artificial holiday trees uses an indentation and protrusion interlock system to serve as a key and keyway arrangement for correctly orienting the connectors. This method is old and, because the connecting poles tend to come apart when the tree is lifted or get stuck together, results in tree assembly, disassembly, and safety issues.
A set of connectors that is reliable and that is readily connect in the proper polarity without having to be physically oriented and physically joined, yet is inexpensive to manufacture in quantity, durable, effective, and safer, would be advantageous.
The present electrical connectors use magnetic repulsion for orienting one connector properly with respect to another, and use magnetic attraction for holding two connectors together in the right polarity. Each electrical connector is identical so there are fewer parts required for manufacturing and assembly of the electrical connectors is greatly simplified. The present electrical connectors may be used to improve electrical connection in applications where electrical connectors may be difficult to join because of limited physical access or because of low light conditions.
When inserted into the ends of a conduit, a pair of the electrical conduits can be used to add electricity transfer to the structural conduit, which may have numerous uses as temporary barriers that carry electricity for temporary lighting.
An aspect of the disclosure is an electrical connector having a housing with a top surface and a bottom surface, a first passage and a second passage, and a fixed and a movable terminal in the first and second passages respectively. The first and second passages are spaced apart, open to both the top and bottom surfaces of the housing and run in parallel. There is a first contact on the fixed terminal and a second contact on the movable terminal. There is a magnet in the second passage proximate to the second contact, and its magnetic field runs through the second contact.
Another aspect of the disclosure is that the movement of the movable terminal is limited so that the second contact rises above the top surface of the housing by a predetermined distance.
Another aspect of the disclosure is that the electrical connector has a ferromagnet in the first passage proximate to the first contact of the fixed terminal. A ferromagnet is a device made of ferromagnetic material, that is, material attracted to a magnet but which material is not magnetic.
Still another aspect of the disclosure is that the first and second contacts have complementary surfaces on their expanded portions that interleave when the complementary surfaces are brought together.
An aspect of the disclosure is that the ferromagnet and magnet are torus-shaped and surround but do not touch the first and second, respectively.
Another aspect of the disclosure is that the first and second contacts both comprise an expanded portion, an upper shaft connected to the expanded portion, and a lower shaft. The lower shafts each have hole that receives the upper shaft.
Still another aspect of the disclosure is that the electrical connector has a compression spring in the second passage, which spring is connected to the second contact. The compression spring resists movement of the magnet, which surrounds the contact, toward ferromagnetic material that might be brought near the top surface of the housing.
Yet another aspect of the disclosure is that the fixed terminal is held in place by a spring washer. The spring washer is attached to the lower shaft of the first terminal.
An aspect of the disclosure is that both the first passage and the second passage have a wall therein dividing these passages into upper chambers and lower chamber. Each of the walls has a hole formed therein dimensioned to receive the lower shafts of the first and second contacts, respectively, passing from the upper chambers into the lower chambers. A spring washer in the lower chamber of the first passage is attached to the lower shaft and engages the wall of the first passage to hold the fixed terminal against movement of the first contact with respect to said housing. In the second passage, the lower shaft extends through the wall of the second passage and through a compression spring and a spring washer. The compression spring and the spring washer cooperate with the wall to limit movement of the second contact of the movable terminal above the top surface when the magnet surrounding the second contact is attracted to a ferromagnetic material.
Another feature of the disclosure is that two electrical connectors, can be joined by a pair of wires, one wire running from the first contact of the first of two electrical connectors to the first contact of the second electrical connector and the other wire running from the second contact of the first of the two electrical connectors to the second contact of the second electrical connector.
Another aspect of the disclosure is that the two electrical connectors can be carried near the ends of a conduit with one electrical connector flush-mounted with the first end of the conduit and the other recessed in the second end of the conduit.
Other features and their advantages will be evident to those skilled in the art of electrical distribution from a careful reading of the following detailed description, accompanied by the following drawings.
In the figures,
The present disclosure describes a universal electrical connector. It also describes a pair of such connectors in electrical connection with each other to serve as an extension cord. That extension cord can be carried in a conduit to enable electrical power to be delivered in a structural member for use in temporary barriers with lighting, for example.
The term universal connector means that the connector is neither a “male” connector nor a “female” connector; the same configuration for the present electrical connector is used for both “plug” and “socket,” although the housing shapes may be varied depending on the context of use. Two such connectors can be joined together to pass electricity from one connector to another or the present connector can be used on both ends of an extension cord. Therefore, for example, in an extension cord with an electrical connector according to the present disclosure on each end, either end of the extension cord can be connected to a wall outlet, provided that the wall outlet mates with the present connector. The remaining end of the extension cord can be connected to, for example, an appliance having the same type of electrical connector.
An extension cord as disclosed herein can be inside a conduit with one of the electrical connectors flush-mounted to one end of the conduit and the other electrical connector recessed in the opposing end of the conduit so that a portion of the conduit extends past the connector. That end of the conduit can receive the end of a second such conduit that has an electrical connector flush mounted so the two mating connectors are inside the conduit. Each such conduit added to the previous conduits not only increases the total length of conduit but connects extension cords using the present electrical connectors together in a continuously conductive chain so that not only is the conduit available for a structural purpose (a barrier, a railing or trim piece) but so, too, is the electricity carried by a series of extension cords inside.
The term conduit is used herein to refer to any structural member that has a passage formed in it that generally follows the major dimension of the conduit.
In the present disclosure, electrical connectors are said to connect when they are in a position relative to each other with their contacts touching so as to be able to transfer electricity from one contact of one electrical connector to the other.
Referring now to
Housing 14 may have other features that adapt it to its environment, such as a flange 22 on its top surface 26 and plural ribs 30 that allow it to be inserted flush with the end of a conduit (not shown) and fit there tightly.
Electrical connector 10 has two terminals, a fixed terminal 34 and a movable terminal 38. Fixed terminal 34 includes a contact 42; movable terminal 38 has a contact 46.
Terminal 90 has a lower shaft 106 with a hole 110 formed therein that has interior threads and is dimensioned to receive upper shaft 102. Lower shaft 106 has a cylindrical groove 114, that is, a portion of its length that has a reduced diameter and beyond which on lower shaft in both directions away from groove 114, the diameter of lower shaft 106 is larger. Terminal 90 also has a top flange 118 that, between expanded top 98 and top flange 118, define an annular recess 122. For convenience, reference numbers applied to terminal 90 will be used on the equivalent structures on terminal 34, 38.
A first spring washer 126 is attached to lower shaft 106 or first terminal 34 just above groove 114 and against wall 74 so that expanded top 98 of fixed terminal 34 is held fixed below top surface 26 of housing 14. First spring washer 126 is selected and dimensioned to hold tightly to lower shaft 106 where it is placed because at that location, diameter of lower shaft 106 is slightly larger than the diameter of groove 114. Terminal 34 is restrained from upward movement with respect to passage 50 because of the position of first spring washer 126, which is on one side of wall 74, and top flange 118 is on the other side preventing downward movement of fixed terminal 34 with respect to first passage 50.
In second passage 54, downward movement of terminal 38 is restricted because of top flange 118 but upward movement is not restricted, although it is limited. A second spring washer 130 is mounted to lower shaft 106 at the lower end of groove 114 to prevent vertical movement of terminal 38 that would otherwise enable removal of movable terminal 38 from second passage 54. A compression spring 134 encircles lower shaft 106 above second spring washer 130 and resists vertical movement of movable terminal 38. As movable terminal 38 moves upward, compression spring 134 is loaded and urges movable terminal to recede into second passage 54. When compression spring 134 is fully compressed, second spring washer 130 and compression spring 134 prevent further movement of movable terminal. At that point, expanded top 98 of movable terminal 38 extends above top surface 26 by the same distance that fixed terminal is recessed inside fixed terminal 34.
In
The particular configuration chosen is complementary whether identical or not identical. In this context, complementary
Fixed terminal 34 and movable terminal 38 differ in another respect that that one is fixed and the other is movable. Annular recess 122, seen best in
In movable terminal 38, in annular recess 122 is a ferromagnet 154. Ferromagnet 154 is not a magnet but is a material that, while producing no magnetic field of its own, responds to the magnetic field of a magnet or electromagnet regardless of polarity.
However, to the extent that the magnetic fields of the adjacent magnets 146, 146′ influence ferromagnets 170, 170′, and repel each other, connector 10′ starts to twist and reorient itself, as seen in
As this process of reorientation continues, best seen by comparing
Referring now to
Second electrical connector 186 and a third electrical connector 190 are connected in the same manner in second conduit 162 as if they were an extension cord: second electrical connector 186 is at one end and third electrical connector 190 is at the other end of a pair of wires 194, 198, which may be joined in parallel with insulation and connected to the ends of the terminals (34, 38, in
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