Patent Application
20170317435
Wire cables carry audio and/or video signals for radios, televisions and other telecommunications devices. A variety of cables, including Coaxial (Coax), High Definition Multimedia Interface (HDMI), Digital Video Interface (DGI), Video Graphics Array/Adapter (VGA), and Separation Video (S-Video) cables, may be used to transmit data, i.e., the audio/video signals, while power, in the form of alternating or direct current, may also be conducted along with, or through, the same or adjacent wire cables.
A signal carrying cable generally refers to a collection of two or more wires or conductors including a “hot” line to carry the current/signal, a “neutral” line to complete the current/signal carrying loop, and a “ground” line. Similarly, power cables include wires for negative, positive, and ground. The ground wire serves to protect a user during wire/cable installation and/or prevent damage to interconnected wires/cables during a high voltage/over-current condition. Such high voltage/over-current conditions may be produced by a power surge or a lightning strike.
A ground wire is typically connected to a highly conductive metal structure buried into the ground such as, for example, a copper water main of a residential or commercial building. While the electrical and mechanical connection from the wire/cable to ground is seemingly simple/non-complex, the requirements can be difficult to achieve. For example, a grounding connection between a coaxial cable and ground must pass an over-current condition of one-thousand five hundred and fifty Amperes (1550 Amps.) for six seconds (6.0 sec.) while maintaining electrical integrity to meet the requirements of Underwriters Laboratories (UL). During the electrical test, the connection must carry a load of one-hundred pounds (100 lbs.) for one hour. Meeting both the electrical and mechanical requirements is especially challenging when considering the need to minimize weight and cost. That is, there is constant pressure to reduce the thickness, and consequently, the weight and cost of wire/cables. The foregoing describes some, but not necessarily all, of the problems, disadvantages and challenges related to ground/bonding blocks.
According to various aspects of the disclosure, a grounding block includes a conductive grounding surface configured to electrically ground a wire to a grounded structure, a retention member rotationally fixed about an axis orthogonal to the grounding surface and slidable toward and away from the conductive grounding surface in a direction parallel to the axis, and a biasing element configured to apply a first force to the retention member in the direction toward the conductive grounding surface to electrically ground the wire to the housing to satisfy a first regulatory requirement. A fastener is operative to apply a second force to the retention member in the direction toward the grounding surface to apply a mechanical load to satisfy a second regulatory requirement
In accordance with various aspects, a grounding block includes a conductive housing having a cavity defined by a plurality of internal walls, a first wall of the plurality of internal walls defining a first aperture for receiving a ground wire electrically coupled to a grounding surface, and a second wall of the plurality of walls defining a second aperture and the grounding surface. The grounding surface is configured to electrically contact the ground wire. The grounding block includes a retention block disposed within the cavity of the housing and being configured to be slid toward and away from the grounding surface, a biasing element configured to urge the retention block toward the grounding surface such that a first force is developed between the ground wire and the housing, and a fastener threadably engaging the retention block such that a second force is selectively developed between the ground wire and the housing.
In some aspects, a grounding block for grounding a coaxial cable to a grounding surface includes a conductive housing having an input port configured to receive an upstream end of a cable and an output port configured to receive a downstream end of the cable, the conductive housing having a cavity defined by a plurality of internal walls. The plurality of internal walls include a first wall of the plurality of internal walls defining a first aperture for receiving a ground wire, and a second wall of the plurality of internal walls defining a second aperture and a grounding surface, the grounding surface being configured to electrically contact the ground wire. The grounding block includes a retention block disposed within the cavity of the housing, the retention block being rotationally coupled about an axis orthogonal to the grounding surface and slidable toward and away from the grounding surface in a direction parallel to the axis, a biasing element configured to urge the retention block toward the grounding surface such that a first force is developed between the ground wire and the conductive housing, and a fastener disposed through the second aperture and threadably engaging the retention block, the fastener being selectively rotatable relative to the retention block to develop a second force between the ground wire and the housing upon rotation of the fastener. The first threshold force satisfies an electrical grounding requirement of the grounding block, and the second threshold force satisfies a mechanical loading requirement in addition to the electrical grounding requirement.
Features and advantages of the present disclosure are described in, and will be apparent from, the following Brief Description of the Drawings and Detailed Description.
The bridge 110 is electrically coupled to the input and output ports 102, 104. In the described exemplary embodiment, the bridge 110 is L-shaped and is electrically connected to an integration plate 126 and to a base plate 128. It should be appreciated that the integration plate 126 may be integral with the base plate 128 and is orthogonal to a mounting surface 130 of the base plate 128. The bridge 110, integration plate 126, and base plate 128 may be machined, molded, or otherwise fabricated from a conductive material such as, for example, copper, brass, steel, iron, or the like.
The grounding block 100 includes a retention clip 112 configured to cooperate with the bridge 110 to effect an electrical connection between the bridge 110 and a ground wire 114. In the described exemplary embodiment, the retention clip 112 is U-shaped and includes a web 132 and a pair of legs 136a, 136b extending from opposite ends of the web 132. The web 132 has a threaded aperture 134 for receiving a threaded fastener 124. The bridge 110 includes a pair of apertures 138a, 138b sized and arranged to receive the pair of legs 136a, 136b and define anti-torque surfaces 116 to prevent rotation of the retention clip 112 about an axis 120. While the clip 112 may be fabricated from any of a variety of non-conductive or non-ferrous materials, the retention clip 112 is fabricated from a conductive material including copper, brass, steel, iron, or the like.
The threaded fastener 124 extends through a bore 122 in the bridge 110 and into the threaded aperture 134 of the web 132. A biasing member 140, for example, a coil spring, is disposed between a head 142 of the fastener 124 and an upper surface 146 of the bridge 110. The coil spring 140 may be seated in a recess 144 of the bore 122. The coil spring 140 imposes an upward force F1 on the fastener 124 via the head 142, which, in turn, produces an upward force F2 on the retention clip 112 threadably coupled with the fastener 124.
When the ground wire 114 is disposed between the retention clip 112 and an underside 150 of the bridge 110, the upward force F2 urges the ground wire 114 against a recess 148 formed in the underside 150 of the bridge 110. The upward force F2 provides a first threshold contact force or pressure level (hereinafter “first threshold level”) between the ground wire 114 and the bridge 110. The first threshold level is sufficient to produce an electrical ground path from the bridge 110 to the ground wire 114. The first threshold level is also sufficient to pass the electrical grounding test imposed by Underwriters Laboratory (UL), i.e., passing a current of one-thousand, five hundred and fifty amperes (1550 amps.) for six seconds (6.0 sec.), discussed above.
While a coil spring 140 is disposed between the head 142 of the fastener 124 and the recess 144 to achieve the first threshold level (i.e., the desired level of grounding contact) in the illustrated embodiment, it should be appreciated that other biasing elements are contemplated. For example, in some embodiments, a spring element, such as a cantilever, a washer, or a coil spring, disposed below the retention clip 112 may be employed to urge the retention clip 112 upwardly against the ground wire 114 and the bridge 110.
As will be discussed in greater detail below, the grounding performed by the spring-biased retention clip 112 occurs without further human intervention. That is, once the ground wire 114 is disposed between the retention clip 112 and the recess 148 in the underside 150 of the bridge 110, the wire/cable 106 is grounded by the coil spring 140 with a sufficient level of force/contact, i.e., the first threshold level, to allow the passage of a high current, i.e., 1550 amps., for a relatively long period of time, i.e., 6.0 sec.
The fastener 124 threadably engages the retention clip 112 along the axis 120 such that a second threshold contact force or pressure level (hereinafter “second threshold level”) can be developed between the ground wire 114 and the bridge 110. The first threshold level satisfies an electrical grounding requirement, as discussed above, while the second threshold level satisfies a mechanical loading requirement in addition to the electrical grounding requirement.
The second threshold level is achieved by the same retention clip 112 as was discussed above in connection with the first threshold level. Furthermore, the ground wire 114 is disposed between the retention clip 112 and the bridge 110 in the same manner as described previously. The coil spring 140 also performs in the same manner, i.e., by raising the fastener 124 and retention clip 112 such that the ground wire 114 is urged into contact with the underside 150 of the bridge 110. The difference between the first and second threshold levels relates to a mechanical loading requirement which is satisfied in addition to the first electrical grounding requirement discussed above.
To achieve the mechanical loading requirement, the fastener 124 can be tightened or torqued, for example, by a conventional flat- or Phillips-head screw driver 156 or any tool capable of tightening or torqueing a fastener. The fastener 124 is tightened via rotation relative to the threadably coupled web 132 of the retention clip 112. Tightening of the fastener 124 compresses the coil spring 140 between the head 142 of the fastener 124 and the bridge 110 and, hence, increases the loads F3 and F4 (
The grounding block 100 of the present disclosure is configured to provide a level of assurance that a wire/cable will be properly grounded. This is accomplished by providing the grounding block 100 capable of achieving multiple thresholds or pressure levels, between the retention clip 112 and the ground wire 114. The first threshold level is achieved by a conventional spring-biased clip configured to trap at least one side of the ground wire 114 against a ground contact, that is, the bridge 110. The first threshold level is achieved without the need to dispense a particular level of force or torque through the grounding block 100. That is, once the ground wire 114 is properly placed between the retention clip 112 and the bridge 110, the coil spring 140 provides the requisite grounding force. The second threshold level is achieved by the threaded fastener 124 disposed in series with the coil spring 140. The second threshold level involves the requirement for a tool to impose the requisite grounding force.
When implementing both of the grounding methods, the grounding block 100 can satisfy a combination of electrical and mechanical requirements for wires/cables. The electrical requirement, which is of paramount importance for grounding wires/cables, can be met by a simple spring-loaded mechanism. The more rigorous mechanical requirement can be satisfied with the aid of a special tool. While both grounding steps should be implemented to optimally protect the devices serviced by the wire/cable, the grounding block 100 ensures that the electrical requirement will be achieved, even if the step of mechanically tightening the retention clip 112 is not performed and, consequently, the mechanical requirement is not met.
In the described embodiment, the housing 210 includes an integration plate 228, a rectangular body 230 integrated with, and projecting upwardly from, the integration plate 228, and a dorsal ring 232 integrated with an aft end of the rectangular body 230. The input and output ports 202, 204 extend away from one another on opposite sides of the dorsal ring 232. The integration plate 228 includes mounting apertures 234 for receiving fasteners (not shown) operative to attach the housing 210 to an electrically grounded plate or surface 236.
Referring to
The dorsal ring 232 is integrated with the aft support and upper walls 242, 244 of the body 230 and is substantially parallel to the sidewalls 246, 248 thereof. Structurally, the dorsal ring 232 mounts each of the input and output interface ports 204, 208 such that an electrical ground path is produced between the grounding conductor within the coaxial cable 206 and the rectangular body 230 of the housing 210.
The housing 210 defines a cavity 250 that contains a retention block 212. The retention block 212 cooperates with the housing 210 to effect an electrical connection between the grounding plate 236 and the ground wire 214. The described embodiment shows the grounding wire 214 extending from the body 230 through an aperture 238 of the grounding plate 236. However, it should be appreciated that the grounding wire 214 may be attached to the grounding plate 236 by any of a variety of methods including welding, soldering, clamping, or the like.
The biasing element 244 is operative to urge the retention block 212 toward the housing 210 such that the first threshold level may be developed between the ground wire 214 and the grounding surface 236 of the housing 210. The retention block 212 resembles a shoe having a heal portion 270 and a forward sole portion 280. The heal 270 defines a contoured upper surface 272, and the forward sole 280 defines a threaded aperture 282. The heal 270 is aligned with the second aperture 262 of the sidewall 246 to engage the ground wire 214 while the sole 280 is aligned with the first aperture 260 to engage the threaded fastener 224. The upper surface 272 of the heal 270 is contoured to compliment the peripheral surface of the ground wire 214 when compressed against the underside surface 264 (i.e., a grounding or conductive surface) of the upper wall 244. A lower surface 274 of the heal 270 abuts a removable portion 276 of the integration plate 228 which closes the cavity 250 of the housing 210. The lower abutment surface 274 limits the downward motion of the retention block 212 when an operator depresses a head 278, for example, a hexed-shaped head, of the fastener 224 to insert the ground wire 214 into the second aperture 262. These operating modes will be discussed when describing the operation of the grounding block 200 with respect to
In the described embodiment, the biasing element 244 is a coil spring disposed between the removable portion 276 of the integration plate 228 and the sole 280 of the retention block 212. As such, the coil spring 240 biases the retention block 212 upwardly, to capture the ground wire 214 when it is insert through the second aperture 262 of the body 230, between the contoured upper surface 272 of the retention block 212 and the underside surface 264 of the housing 210. The coil spring 240 imposes an upward force F5 on the fastener 224 which, in turn, produces an equal or substantially equivalent, upward force F5 on the retention block 212. The upward force F5 urges the ground wire 214 against the underside surface 264 of the body 230 at least at the first threshold level. In the described embodiment, the first threshold level is sufficient to produce an electrical ground path from the housing 210 to the ground wire 214. This threshold level is also sufficient to pass the electrical grounding test imposed by Underwriters Laboratory (UL), i.e., passing a current of one-thousand, five hundred and fifty Amperes (1550 amps.) for six seconds (6.0 sec.), as discussed above.
While the first threshold level is achieved by the coil spring 240, it should be appreciated that other biasing elements are contemplated. For example, a cantilever, washer, or coil spring, may be employed beneath the retention block 212 to apply the first force F5 to the ground wire 214.
As will be discussed in greater detail below, the grounding performed by the spring-biased retention block 212 occurs without further human intervention. That is, once the ground wire 214 is disposed between the retention block 212 and the upper wall 244 of the housing 210, the wire/cables 206 are grounded by the coil spring 240 to allow a high current/over-current condition, i.e., 1550 A for 6.0 seconds.
As best illustrated in
The fastener 224 threadably engaging the retention block 212 such that a second contact pressure or force F6 may be developed between the ground wire 214 and the housing 210. The first threshold level satisfies an electrical grounding requirement while the second force F6 meets or exceeds the second threshold level, which satisfies a mechanical loading requirement in addition to the electrical grounding requirement.
A second force F6, between the ground wire 214 and the housing 210, is achieved by the same retention block 212 as was discussed above in connection with the first threshold level. Furthermore, the ground wire 214 is disposed between the retention block 212 and the housing 210 in the same manner as described previously. The coil spring 240 also performs in the same manner, i.e., by lifting or raising the fastener 224 and retention block 212 such that the ground wire 214 is urged into contact with the underside 244 of the housing 210.
The second threshold level, and thus the second force F6, is higher than the first threshold level and the first upward force F5. The second force F6 is achieved by turning the threaded fastener 224 until the hex-shaped head 278 seats against or contacts the upper wall surface 292 of the housing 210. The difference between the first and second threshold F5, F6 generally relates to the second mechanical loading requirement which is satisfied in addition to the first electrical grounding requirement discussed above. To achieve the mechanical loading requirement, the fastener 224 is tightened or torqued (i.e., by a conventional flat- or Phillips-head screw driver or any tool capable of tightening or torqueing a fastener) to increase the force couple produced between the sole 280 and heal 270 of the retention block 212. As the head 278 of the fastener 224 rotates about the fastener axis 220, the second force F6 is produced along the fastener axis 220 which, in turn, produces an equal or substantially equivalent second force F6 on the retention block 212. The second threshold force F6 imposed on the retention block 212 by the threaded fastener 224 can be significantly higher than the first force F5 imposed on the retention block 212 by the coil spring 240. In the described embodiment, the second threshold level, i.e., the force imposed by the retention block 212, is sufficient to carry a load of one-hundred pounds (100 lbs.) for one hour (60 hr.) as the load is rotated in a pendulum-like circular path.
The grounding block 200 of the present disclosure is configured to provide a level of assurance that a wire/cable will be properly grounded. This is accomplished by providing a grounding block 200 capable of applying multiple force thresholds, between a retention block 212 and a ground wire 214. In
In
When implementing both of the grounding methods, the grounding block 200 can satisfy a combination of electrical and mechanical requirements for wires/cables. The electrical requirement, which is of paramount importance for grounding wires/cables, can be met by a simple spring-loaded mechanism. The more rigorous mechanical requirement can be satisfied with the aid of a special tool and/or by preselecting dimensions between a threaded fastener 224 and retention block 212.
While both grounding steps should be implemented to optimally protect the devices serviced by the wire/cable, the grounding block 200 ensures that the electrical requirement will be achieved, even if the step of mechanically tightening the retention block 212 is not performed and, consequently, the mechanical requirement is not met.
In the described embodiment, the rotational position of the retention block 212 is fixed so that block 212 does not rotate about the fastener axis 220. While the block 212 is configured to slide along the vertical axis 220 of the fastener 224, it will be appreciated that the retention block 212 may slide laterally along a horizontal axis to capture a ground wire, i.e., apply first and second threshold forces, against one of the sidewall structures. In such an embodiment, the first and second apertures for receiving the ground wire 214 and fastener 224 would be reversed. That is, the first aperture for receiving the ground wire 214 would be in the upper wall and the second aperture for receiving the fastener 224 would be in one of the sidewalls.
According to various aspects, the input and output ports 102, 104, 202, 204 may be female interface ports including a stud or jack, such as a cylindrical stud, as illustrated in
In one embodiment, the stud of the input and output ports 102, 104, 202, 204 is shaped and sized to be compatible with the F-type coaxial connection standard. It should be understood that, depending upon the embodiment, stud could have a smooth outer surface. During installation, the installer couples the cable 106 to each of the input and output ports 102, 104, 202, 204 by screwing or pushing a connector (not shown in detail) onto the port. Once installed, the connector receives the female interface port. The connector establishes an electrical connection between the cable and the electrical contact of the female interface port. The input ports 102, 202 are also electrically coupled with the respective output ports 104, 204.
Additional embodiments include any one of the embodiments described above, where one or more of its components, functionalities or structures is interchanged with, replaced by or augmented by one or more of the components, functionalities or structures of a different embodiment described above.
It should be understood that various changes and modifications to the embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present disclosure and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
Although several embodiments of the disclosure have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the disclosure will come to mind to which the disclosure pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the disclosure is not limited to the specific embodiments disclosed herein above, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the present disclosure, nor the claims which follow.
This application is a Continuation of U.S. patent application Ser. No. 14/858,773, filed Sep. 18, 2015, pending, which claims the benefit of U.S. Provisional Application No. 62/052,055, filed on Sep. 18, 2014, and U.S. Provisional Application No. 62/130,053, filed on Mar. 9, 2015, the disclosures of which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62052055 | Sep 2014 | US | |
| 62130053 | Mar 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14858773 | Sep 2015 | US |
| Child | 15457787 | US |
