Local area network (LAN) communications between various systems and devices is ubiquitous. For example, existing electronic infrastructures are commonly outfitted with devices compatible with the Ethernet standards, including those for power-over-Ethernet (PoE), 100Base-T, 10Base-T, and other similar protocols. Ethernet interfaces can be found in devices such as IP telephones, wireless LAN access points, network cameras, building automation devices, security devices and the like.
Wired Ethernet data transmission at speeds of 100 megabits per second requires cabling that can sustain a 100-125 MHz bandwidth. Such a bandwidth can be maintained by using differential data transmission and other techniques to minimize interference. An appropriate impedance must be maintained throughout the data transmission path to maintain data integrity. Maintaining such an impedance is typically not a problem with long cables where there are no severe bends or discontinuities, but can be difficult in tight spaces. Where cables must turn or be severely constrained, discontinuities can occur.
Embodiments of the present invention provide a door hinge that facilitates transmission of data from LAN wiring in a building through a door frame to a door mounted device. In at least some embodiments, power or other signals can also be transmitted through the hinge. In at least some embodiments the door hinge is fast Ethernet capable, having a center frequency of up to 100 MHz so that it can pass 100Base-T (100 megabits per second) Ethernet signals. The door hinge of embodiments of the invention may be referred to as a “data transfer hinge” and can be made to be compatible with wiring specified in the TIA-EIA-568 telecommunications standard for Ethernet cable.
A data transfer hinge according to at least some embodiments of the invention includes a first leaf and a second leaf, each having at least one knuckle. Each leaf also has at least one channel running from an edge coincident with the knuckle or knuckles to a passageway in a face of the leaf. The passageway opens into the channel. As is typical with door hinges, the knuckle or knuckles of the first leaf and the knuckle or knuckles of the second leaf are arranged to be relatively rotatable around a common axis in accordance with the normal functioning of a hinge. A twisted pair of data wires having a specified number of twists per unit length runs through the passageway in the face of each leaf and through the channel in both the first leaf and the second leaf A pin or pins with a void can be used to pass the wires from one hinge leaf to another. Additional spacers may be used to pass wires into and out of the pin. Each wire of the twisted pair of data wires is of a gauge and has insulation of a specified thickness and permittivity so as to cooperate with the channel in the hinge leaves to maintain an even distribution of capacitance and appropriate impedance for connection within a local area network.
In at least some embodiments, for example, for use in Ethernet systems, there are two channels machined into each leaf for differentially driven wiring, one for each of two twisted pairs of data wires. In some embodiments, both of two twisted pairs of data wires run through a single channel. An additional passageway on the face of each leaf and additional channels can also be provided for additional wires. Alternatively, the additional wires can be run through the same channel as one or more of the twisted pairs of data wires. In example embodiments, these additional wires can be straight wires, as opposed to twisted pairs, and can be used for power, ground, or other purposes for which high data transfer rates are not needed. Connectors can be provided at the ends of all wires to connect the hinge to a door frame harness assembly that in turn is connected to building wiring, as well as to a door-mounted device, possibly through a door harness assembly. Shielding may be provided for the twisted pairs of wiring that run from the passageways in the leaves to the connectors.
In at least some embodiments a number of twists per unit length for the twisted pairs of data wires is about 1.5 twists per inch. In some embodiments, the gauge of the data wires is 26AWG and a channel is machined by boring with a 2 millimeter bit. In some embodiments, a channel can be machined by forming a slot using electrical discharge machining. In some embodiments, the specified thickness of the insulation on the data wires is about 0.006 inches and the permittivity of the insulation on the data wires is about 2.1.
The following detailed description of embodiments refers to the accompanying drawings, which illustrate specific embodiments of the invention. Other embodiments having different structures and operation do not depart from the scope of the present invention.
Embodiments of the present invention consist of a hinge with wire runs through machined channels within the hinge leaves. Signal integrity for differential data pairs of wires through their respective channels can be comparable with that specified for the well-known IEEE 802.3 standards for frequencies up to 100 MHz. Signal integrity is maintained by providing coupling twists at a specified number per unit length for each differential data pair of signal wires. The twists induce a current equally and oppositely from one wire of a pair to the other, providing appropriate isolation of data wires to prevent excessive capacitive coupling to ground or between wires.
In example embodiments, insulation of a specified thickness and permittivity coats each wire of the differentially driven, twisted pairs of data wires. This insulation cooperates with the air gap between the wires and the channels to reduce fringe capacitance to ground and to maintain an even distribution of capacitance throughout the data transfer hinge so as not to create an impedance mismatch. In example embodiments, the impedance of the twisted pairs of data wires is 100 ohms at 100 MHz. In some embodiments, the portions of the twisted data pairs of wire between a passageway out of the hinge leaf and the connectors is shielded, for example, by using shielded heat shrink tubing, to further protect signal integrity.
In some environments, power would also be transmitted over the twisted data pairs. However, in some embodiments the data transfer hinge is provided with separate straight through wires for power and ground. In some embodiments, the data transfer hinge has an additional conductor running through the hinge for earth ground to provide for electrostatic discharge (ESD) protection of connected components and/or devices. This ground wire provides a drain from the door-mounted device to prevent ESD voltages from being propagated on the LAN data lines. The data transfer hinge in at least some embodiments can be outfitted using wire insulation colors that match the well-known TIA-EIA-568 standard (either the “A” standard or the “B” standard) for Ethernet LAN wiring. Appropriate connectors can be provided for quick connect termination to mating frame and door wiring harnesses, or the hinge could be supplied without connectors on one or both ends of one or both of the cables, that is, with so-called “flying leads” so that appropriate connectors could be installed in the field. It would also be possible to provide standard LAN connectors, such as RJ-45 Ethernet connectors.
Still referring to
Data transfer hinge 200 as illustrated in
Still referring to
Staying with
As previously mentioned, each wire of the twisted pairs of data wires is of a gauge and has insulation of a specified thickness and permittivity so as to cooperate with the channel in the hinge leaves to maintain an even distribution of capacitance and appropriate impedance for connection within a local area network. The appropriate impedance can be maintained despite varying electrical potential of the hinge body. In example embodiments, this impedance is approximately 100 ohms at 100 MHz. Either stranded or solid wire can be used in the hinge, for both the twisted data pairs of wires and the straight wires. Twisting at a specified number of twists per unit length contributes to maintaining signal integrity and preventing excessive capacitive coupling to ground or between wires. At least many of these characteristics interact to determine the impedance characteristics of the hinge. If any one of these parameters are varied, others can be adjusted to compensate. Shielding of the portion of the twisted pairs is optional, but can improve signal integrity. The ground wire running through the hinge can be included to provide ESD protection for connected devices.
Strip-line assumptions can be used for initial calculations to set the parameters of a data transfer hinge according to example embodiments of the invention. Trial and error can then be used together with empirical testing to design a hinge. Assuming the hinge is to be used in an Ethernet LAN, standard Ethernet compliance test parameter evaluation procedures can be used to verify and adjust the design when varying parameters such as the channel size and shape, wire gauge, type and amount of insulation, etc.
The following specific design parameters have been found to produce a data transfer hinge like that shown in
It should be noted that the term “twists per inch” or indeed, twists per any unit length, may have different meanings. The figure is sometimes used to represent the number of turns or “waves” of a single wire of the twisted pair per unit length of the pair. Alternatively, the figure sometimes refers to the number of times per unit length that the two wires cross. It is the former meaning that is intended here. The same physical twisted pair of wires that is described herein as having about 1.5 twists per inch could also be described as having about 3 twists per inch if the latter meaning is understood.
As previously mentioned, wire insulation can be used to impart color coding to the individual wires in accordance with a wiring standard. For example, wire insulation colors for compliance with the Ethernet TIA-EIA-568B wiring standard can be used so that the eight wires running through the hinge in the examples presented herein match the eight wire colors used in that standard. In such a case, the wires of one of the twisted pairs would appear green, and white/green. The wires of the other twisted pair would appear orange and white/orange. The straight wires through the hinge would appear brown, white/brown, blue and white/blue. For the ground wire in example embodiments, since it is not specified in the standard, any color insulation can be used, for example, green, or green with a yellow stripe.
The two jackets leaving a leaf of the hinge could be brought close together and the wires connected to a standard LAN connector such as a male or female RJ-45 connector used in Ethernet systems. Alternatively, the wires emerging from each jacket could be terminated in a connector, making for two connectors to the hinge in the door and two connectors to the hinge in the door frame. For example, four-pin Molex™ connectors could be used for the twisted pairs, and six-pin Molex connectors could be used for the four straight wires and the ground, with one pin unused (as pictured schematically in
It should be noted that an embodiment of the data transfer hinge could be developed that relied on a combination of machining methods for forming the channels needed for the various wires. For example, one or more channels could be bored and one or more could be formed by using EDM. It may also be possible to produce an embodiment with a single channel and/or passageway for each leaf of the hinge where all wires pass, for example, by forming one slot in each leaf using EDM. In any such case, the various other design parameters previously discussed can be varied to achieve an appropriate impedance so that the hinge can be used to pass LAN traffic.
Still referring to
It should be noted that the cabling and connectors shown in
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof. Additionally, comparative, quantitative terms such as “less” or “more”, are intended to encompass the concept of equality, thus, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”
It should also pointed out that references made in this disclosure to figures and descriptions using positional terms such as, but not limited to, “top” and “bottom” refer only to the relative position of features as shown from the perspective of the reader. Such term are not meant to imply any absolute positions. An element can be functionally in the same place in an actual product, even though one might refer to the position of the element differently due to the instant orientation of the device.
Although specific embodiments have been illustrated and described herein, those of ordinary skill in the art appreciate that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiments shown and that the invention has other applications in other environments. This application is intended to cover any adaptations or variations of the present invention. The following claims are in no way intended to limit the scope of the invention to the specific embodiments described herein.
This application is filed under the provisions of 35 U.S.C. §371 and claims the priority of International Patent Application No. PCT/US2010/028851 filed on 26 Mar. 2010 entitled “DATA TRANSFER HINGE” which claims priority from commonly owned non-provisional U.S. patent application Ser. No. 12/413,943 filed Mar. 30, 2009, now U.S. Pat. No. 7,824,200, the entire disclosure disclosures of both of which are hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US2010/028851 | 3/26/2010 | WO | 00 | 9/29/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/117682 | 10/14/2010 | WO | A |
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Number | Date | Country | |
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20120021628 A1 | Jan 2012 | US |
Number | Date | Country | |
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Parent | 12413943 | Mar 2009 | US |
Child | 13262156 | US |