The object of the invention is to provide a compact, expandable and aesthetically pleasing arrangement for a mobile radio base station, particularly a low power base station, housing equipment supporting multiple channels and protocols, together with sensors, cameras or other equipment.
The development and expansion of macro cellular radio services has led to the proliferation of antennas and associated hardware such as filters and tower-mounted remote radio units (RRUs). Continued expansion is hampered by the lack of space on supporting structures, the high wind load that results from an assemblage of multiple separate pieces of radio equipment and antennas, and their unacceptable visual profile.
Small cells provide mobile radio services over smaller distances than the higher powered macrocells, so the size and weight of the associated antennas and radio equipment is smaller. It was expected by network operators that small cells, which add capacity and coverage to complement that provided by macrocells, could be mounted on lightweight structures, including existing infrastructure poles, and would present no significant issues in terms of public acceptability, requiring minimal additional planning/zoning permission.
Unfortunately, this has proved not to be the case. Small cells are typically deployed on lighting poles, bus shelters, the sides of buildings, or power lines, in any area where it is possible to put them without creating objections by local residents. In practice, equipment installed by multiple network operators, and supporting a variety of radio interface standards, is already cluttering the visual environment. Unless an improved solution is implemented, extension of the existing infrastructure to provide 5G and other future services can only exacerbate the present unsatisfactory situation, which is already receiving criticism in the media.
As shown in
Small cells are typically arranged to create full 360° azimuthal coverage, obtained by combining multiple antenna arrays firing radially in directions separated in azimuth bearing, typically by 120°. While this is a low cost solution, it typically creates an azimuthal radiation pattern, referred to as a pseudo-omnidirectional pattern, which may depart significantly from an ideal circle.
A variety of environmental sensors are commonly co-located with small cells, whose connectivity provides a route for the collected data. Such sensors may include cameras, meteorological sensors and air quality monitors. While these serve necessary requirements they further add to visual clutter. Hereinafter these are collectively referred to as IoT (internet of things) devices.
There are several prior art solutions that hide the unsightly radios, brackets and cables in a small cell, a typical example being a small cell “smart pole” outlined in patent application US2017/0279187 A1. This describes methods to hide the radio equipment in the interior of a precast concrete pole and route the cables inside it to the antenna. This hides the unsightly radio equipment, but requires new deployments of poles. It is a good solution for new site installations but the replacement of existing poles is not cost effective considering the relatively low cost of the radio equipment and antennas to be installed on it.
Catenary wires, typically supported by concrete, metal or wooden utility poles, are widely used to support existing power and/or communications cables, together with ancillary equipment such as repeaters and amplifiers. It is known to provide “fiber nodes” on such catenary cables whose function is to convert optical signals to radio frequency (RF) signals to be delivered to homes.
In the light of the foregoing, there exists a need for an integrated and economic solution that can be deployed on existing infrastructure in large numbers to provide for the expansion of small cells to provide the increased capacity needed. Such base stations should preferably provide for multiple current communications technologies and for new technologies as these become available in the future, optionally sharing with other public infrastructure hardware such as street lighting, traffic cameras and sensors. The present invention provides a solution that is attractive both to operators and to the communities they serve.
According to the invention there is provided a novel integrated and expandable hardware and communications platform designated a Fiber Integrated Radio Equipment for Network Optimization & Densification Ecosystem (FIRE-NODE). A FIRE-NODE fully integrates antennas, radios and associated computational and data management circuit arrangements into one physical enclosure, and provides shared single external connections for fixed network connectivity, power and control facilities. This provides an aesthetically pleasing appearance, higher reliability, improved technical performance and lower cost for operation and future expansion. It realizes the possibility of the cooperative development of small cells and other public infrastructure, enabled by its provision of standard common facilities.
According to a first embodiment, a FIRE-NODE is a small cylindrical housing providing accommodation for more than one wireless technology, IoT devices, cameras and sensors, using a single power line and a single optical input. In the preferred embodiment, the radio architecture is modular with a distributed structure that facilitates thermal dissipation within the base station enclosure.
According to a second embodiment a FIRE-NODE is in the form of a rectangular panel with a metallic back frame that may incorporate heat-dissipating fins to provide cooling for the enclosed electronics modules. Such an arrangement provides an external appearance similar to that of the standard macro cellular construction with each FIRE-NODE forming a panel; multiple panels may grouped to serve users in a multiple azimuth sectors each typically 120° wide.
According to a third embodiment a FIRE-NODE is housed in a protective radome and is supported from a substantially horizontal catenary wire, typically stretched between utility poles or buildings. Such an arrangement may comprise two assemblies of functional modules positioned to provide service to users on both sides of the supporting catenary wire. For reference, this FIRE-NODE will be referred to as a Strand Line Mount FIRE-NODE or SLiM FIRE-NODE for short.
It will be understood that the application of the present invention provides a means by which the functionality of existing urban and rural utility infrastructure may be substantially increased.
A FIRE-NODE according to the invention is provided with at least one input power port, and at least one external communication port which may have any preferred physical interfaces) (for example coaxial line or optical fiber) and may use any chosen data protocol (for example Ethernet).
Internal arrangements within the FIRE-NODE distribute the power and external communications facilities to the contained multiple radio units and other electronic circuits to enable their independent operation and provision of wireless coverage to serve surrounding users.
Some of the main technical advantages of the approach provided by the present invention are:
i. the effective gain of contained antennas is increased by the elimination of external coaxial jumper cables connecting separate units of radio equipment;
ii. installation time and effort are reduced since only one physical unit is deployed instead of numerous separate and interconnected units as required by prior art;
iii. fewer power lines and signal lines as well as less mounting space are required by comparison with prior art arrangements since connectivity and physical accommodation are shared between multiple installed devices, including devices using different technologies (for example 3G, 4G, 5G, WiFi) and functionalities (for example radio units, sensors and cameras);
iv. the visual profile of a FIRE-NODE is less cluttered than a prior art arrangement of separate units.
In describing the illustrative, non-limiting embodiments of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents that operate in similar manner to accomplish a similar purpose. Several embodiments of the invention are described for illustrative purposes, it being understood that the invention may be embodied in other forms not specifically shown in the drawings.
Turning to the drawings,
The interface module 142 has electronic circuit arrangements for the management of the functional modules 27, 28, 29, the conversion of data transmission protocols between an external data connection 31 and an internal data bus 32 connected between the interface module 142 and each of the functional modules 27, 28, 29. Further electronic circuit arrangements in the interface module 142 can convert power provided by the external power connection 30 to a level suitable for connection an internal power bus 33 to supply each of the functional modules. For example, the interface can convert the high power voltage input to a low power voltage that is suitable for the module components. Thus, the interface conditions the power and data signals to be suitable for operation of the functional modules which can, for example, include circuit devices that are low power. In addition, the functional modules can be separate and discrete devices that are substantially planar and transmit and receive data for bidirectional communications.
By way of examples, the external data connection 31 may be provided by an optical fiber or coaxial cable and may use a protocol such as eCPRI, while the internal data bus 32 may use Ethernet or other local-area network protocol. External power 30 may typically be provided at 115 V or 230 V AC, while the power bus 33 may operate at 24 V or 90 V DC. In a preferred embodiment there is provided a single external data connection and a single external power connection to interface unit 142. Having a single interface 142 avoids the necessity for each functional module to have its own power conversion and other circuitry such as lightening protection; though in one embodiment each module 83, 50, 124, 115, 119 can be directly connected to the incoming power 143 at the interface 142, and each module would include power conversion frons high voltage to low voltage.
Management of the functional modules 27, 28, 29 may comprise capabilities such as the adjustment of the power, frequency and other operational parameters of radio modules, the control of one or more camera modules and sensor modules, the storage of log-files and the recording of data.
The modular format of a FIRE-NODE small cell 100 according to the invention designed to enable the addition of further functional modules, which may extend those functionalities provided at the time of initial deployment or may provide additional functionalities. Thus, fewer or more functional modules can be provided other than the three functionalities 27, 28, 29 illustrated in the embodiment shown.
The interface module 142 may be combined with and integral to any functional module, but it may be advantageous that it be separate for logistical reasons. As shown, the functional modules 27, 28, 29 can be linearly arranged within the housing 26 of the base station 100. And, mechanical connections such as fasteners or the like can be provided to connect the functional modules 27, 28, 29 within the housing 26.
The data management capabilities of the interface module 142 preferably provide for future upgrades of operational software and hardware for the functional modules comprising the FIRE-NODE small cell and for the addition of further functional modules including modules embodying future technologies.
As further illustrated in
The power connectors 35, 37 at the first and second edges are galvanically connected by elongate conductive elements forming a power bus 36 and the data connectors at the first and second edges are electronically connected by circuit tracks forming a data bus 39. The data bus 39 may connect connectors 38, 40 by a galvanic connection or by way of an electronic data communications circuit.
The power bus 36 may have at least one of a conductive printed circuit track or elongate solid conductor or a combination of at least one conductive track and at least one solid conductor. Where multiple conductive paths are provided, they may be connected in parallel, for example to increase the current carrying capacity of a single conductive track, or they may form independent current paths, for example to provide more than one supply voltage for connection to the functional module 34 or to other functional modules connected thereto. That is, the interface (in this embodiment and other embodiments) can provide different power outputs, each having a same or different voltage.
In one embodiment, the first power connector 35 can be an input and the second power connector 37 can be an output. And the first data connector 38 can be an input and the second data connector 40 can be an output. The power bus 36 connects the input power connector 35 with the output power connector 37. The data bus 39 connects the input data connector 38 to the output data connector 40 and comprises at least one printed circuit track. The electronics circuit device 41 is galvanically connected to the power bus 36 by conductive element 164 and to the data bus 39 by the conductive element 166. It will be understood that the electronics circuit device may be connected to at least one of the conductors forming the power bus by conductive element 164 and at least one of the conductors forming the data bus by conductive element 166. Conductive elements 164 and 166 may each comprise one or more conductive tracks or wires and may be connected by soldering, by demountable connectors, by insulation displacement connectors or by a combination of these methods.
The supporting member 156 may be substantially planar, formed from metal such as aluminum alloy by extrusion or from folded sheet, or by injection molding of a suitable thermoplastic material such as high-impact polystyrene. The supporting member may be provided with attachment locations and attachment features or mechanisms for the printed circuit board 101, the connectors 35, 37, 38, 40, the printed circuit board 101 and the electronics circuit device 41 as well as features providing for its attachment to a chassis member 141 shown on
The printed circuit board 101 is preferably constructed using multi-layer technology such that in addition to the power and data buses it may physically support and provide power and data connection to at least one electronic circuit device 41 formed thereon or supported thereby such as at least one of a radio unit, sensor, camera or other functional device. The printed circuit board is preferably provided with at least one planar conductive ground plane that acts as a common ground between the power and data buses 36, 39 and the at least one electronics circuit device 41.
The first or input power and data connectors 35, 38 at the first edge of the printed circuit assembly 101 are preferably of female configuration, while the second or output connectors 37, 40 at the second edge are of male configuration. In one embodiment, the connectors are industry-standard printed circuit card edge connectors in which the male contacts are formed by conductive tracks 200, 201 etched on the circuit board 101 and are preferably plated with gold to provide corrosion resistance and low contact resistance. In one embodiment, the printed circuit board 101 is oriented such that the male contacts are on its upper edge and the female connectors are on its lower edge. In one embodiment, the connectors are Amphenol Cool Edge™ connectors for data and Amphenol Cool Edge™ PowerGuide connectors for the power bus.
It will be readily understood that the configuration described permits a plurality of printed circuit boards 101 of the various functional modules 50, 83, 115, 119, 124 (
There is also provided a second data bus 47 oriented substantially orthogonally to the first data bus 39, and terminated by third and fourth data connectors 46, 48 on the third and fourth edges respectively of the printed circuit board 101. Conductive members of the second data bus 47 may be connected to those of the first data bus 39 by electronic circuit arrangements. It will be understood that this configuration facilitates additional topologies for the connected functional modules, having physical and electrical connections in both vertical and lateral planes. In one embodiment, the third power and data connectors 43, 46 can form inputs, and the fourth power and data connectors 45, 48 can form outputs.
A fully configured FIRE-NODE small base station may comprise base modules having the configuration of
In addition, the male data connector 40 of the second functional module 163 is received by and engaged with the female data connector 38 of the first functional module 162. This electrically connects the data bus 32 of the second functional module 163 with the data bus of the first functional module 162. In addition, referring to
The functional modules can have any suitable electronic components that are connected to the power bus and the data bus.
It will be seen that the arrangement of
It will be seen that the arrangement of
It will be understood that the arrangement of
The 5G-NR radio module installed in a small base station 100 according to the invention may provide data services to proximate users, a link providing connectivity between a WiFi access point and the public fixed network or a link to other base stations.
The channels 151, 152 have two side walk and inwardly-facing arms substantially orthogonal to the side walls that come together to form the central opening that receives the neck of the screw. However, the opening is narrower than the head of the screw, so that the screw does not come free of the channel. The screw is inserted into and removed from the channel at openings in the channel at the distal top and bottom ends of the support 141, or at widened openings provided at other locations along the length of the channels 151. 152. The elongate channels 151, 152 are formed at the top planar surface of the support 141 and extend along the longitudinal length of the member 141 substantially parallel to each other and the sides of the member 141. The channels 151, 152 slidably receive the screw 153 heads, while only permitting the threaded body to protrude through the opening. Of course, any suitable configuration can be provided to removably couple the modules 98 with the support 141, other than the use of channels, such as fasteners or the like.
One or more functional modules such as 83, 98 provided with corresponding mounting holes may be fixedly attached to the member 141 by means of nuts 154 engaged on the T-bolts 153. The screws 153 slide within the channels 151, 152 so that the respective connectors of the modules 83. 98 align with one another and can engage and disengage one another. Once connected, the modules can be locked to one another to provide a reliable connection and avoid inadvertent disconnection. An alternative implementation using headed nuts (for example “T-nuts”) and corresponding standard set screws is also possible and is shown in
A further implementation is shown in
It may be seen that while the lateral dimension of each functional module contained within a small base station according to the present invention must be sufficient to support the bus connectors at a standard spacing common to all installed functional modules, the longitudinal dimension of any module, being the height of such modules as installed in the structural member 141, is not constrained, so modules having different functionality may be dimensioned to provide the appropriate area for the circuit components and antennas required to perform each specific function.
Weather protection for the contents of the small base station may be provided by a radome 157 formed from material with a low dielectric loss such as polystyrene or glass-reinforced polyester resin (Fiberglass), which allows signals to pass without interference. The radome may be secured to the structural member by means of screws or rivets or by a feature 158 formed in an extruded radome 157 and a corresponding groove 156 formed in the proximate edges of the support member 141 such as shown in
A functional module 305 is formed on the printed circuit board 101 and has a module power connector 314 and module data connector 311 that removably engage with the mating power connector 312 and data support connector 313 mounted on the elongate printed circuit board 300, 301, respectively. In this way connector pairs 312, 314 and 311, 313 provide mechanical support for functional module 305 as well as providing it with electrical connections to the power bus 300 and data bus 301. The module connectors 314, 311 attached to the functional modules are preferably of male format and the connectors 312, 313 on the printed circuit board 302 secured to the support member 141 are preferably of female format.
Accordingly, the power bus connectors 312 are attached to the power bus 300 at various fixed locations along the length of the power bus 300. And, the data bus connectors 313 are attached to the data bus 301 at various fixed locations along the length of the data bus 301 in alignment with the power bus connector 312. In addition, a first power bus connector 312 and a first data bus connector 313 are each positioned on the support 141 at a location corresponding to top end of the functional module 305, and a second power bus connector 312 and a data bus connector 313 are each positioned at a location along the support 141 corresponding to a bottom end of the functional module 305. The first power bus and data bus connectors 312, 313 align with and connect to respective multi-pole power and data module connectors 314, 311 positioned toward the top end of the module 305, and the second power and data bus connectors 312, 313 align with and connect to respective multi-pole power and data module connectors 314, 311 positioned toward the bottom end of the module 305.
Thus, as shown in
And, at least one conductive member or data bus 301 and at least one conductive member or power bus 300 are supported by the printed circuit board 300. The power and data connectors 312, 313 are provided on a front face of the printed circuit board 300. The module power and data connectors 314, 311 are provided on a rear face of functional module 305 and removably connect with the power and data connectors 312, 313, respectively. Antennas, cameras or other functional devices are provided on a front face of the module.
In this manner, power is provided from the power bus 300, through the top and bottom power connectors 312, the module power connectors 314, to the power bus internal to the module 305 where it provides power to all internal components. The very bottom connector 312 is connected to the interface 142, and the very top connector 312 can be a female connector that connects with other base stations. Data is provided from the data bus 301, through the top and bottom support data bus connectors 313, the module data connectors 311, to the data bus internal to the module 305 where it provides data to all internal elements.
In one aspect of the invention the power and data bus conductors may be formed by a multi-conductor cable such as a so-called “ribbon cable” and the connectors may be standard insulation displacement connectors. In one implementation of the data bus the multi-conductor cable may extend along substantially the whole length of the structural support member 141 and each functional module may be provided with a single data connector such that the connections to all installed modules appear in parallel across the data bus,
To enable the interconnection of the power bus between modules there are provided at least two link modules each comprising two header connectors, namely upper power connector 312a and lower power connector 312b, of female format mounted on a printed circuit board 321 and projecting outwardly therefrom on a first face. Each of the connectors 312a, 312b have the same number of pins as the corresponding power bus connector 314 on the functional module. Each pin of the first or upper connector 312a is linked by a conductive track to the corresponding pin of the second or lower connector 312b.
In like manner to enable the interconnection of the data bus 301 between modules there are provided at least two link modules each having two header connectors of female format, namely first or upper data connector 313a and second or lower data connector 313b, mounted on a printed circuit board 320 and projecting outwardly therefrom on a first face. Each of the connectors 313a, 313b have the same number of pins as the corresponding data bus connector 311 on the functional module 305. Each pin of the first connector 313a is linked by a conductive track to the corresponding pin of the second connector 315b.
It may be convenient to configure a single printed circuit board to support two power bus female connectors 312a, 312b and two data bus female connectors 313a, 313b together with tracks formed thereon to galvanically connect the corresponding pins of power bus connectors 312a, 312b and of data bus connectors 313a, 313b.
It will be understood that the arrangement of
To summarize, in FIG, 13, the support 141 provides a mechanical alignment and connection mechanism and does not contain any electronics, which are all provided by the various modules 98. The modules 98 directly connect to one another, whereby the power and data bus of each module 98 connects with the power and data bus of each adjacent connected module 98.
In
The support 141 can be utilized to mechanically and electrically couple various functional modules.
It will be understood that any combination of functional modules may be configured in the exemplary arrangements shown in
The assemblies 501, 502, 503 can each be mounted to a flat planar panel that are joined together to form the triangular configuration. The central structure 509 is optional, but can be positioned at the center of the triangle and can be circular and contact the panels to further support the triangular structure. The vertical structure 509 can also have a center circular structure and outwardly extending arms extending between the inner center and the outer circular structures to further strengthen the structure 509 and provide extended cooling surfaces for the attached functional modules.
The assemblies 501, 502, 503 may be operated as three independent base stations each providing service in a separate sectoral coverage area or may cooperate to provide a quasi-omnidirectional configuration in which the same transmissions are made from functional modules on each face and are synchronous and co-phased. According to operational requirements the functional modules for some services, for example WiFi transmissions on the 2.4-GHz frequency band may be operated in a quasi-omnidirectional mode, while other modules, for example modules providing for 5GNR services may operate independently on each face of the assembly.
In
Of course, any suitable number of assemblies 501, 502, 503 and functional modules can be provided, more or less than the three shown. And the assemblies can be arranged in other shapes or configurations.
It will be seen in
As indicated diagrammatically, the shape and direction of beams 411, 412, 413 formed by functional modules supporting different radio technologies may differ by design. In some embodiments their shape and direction may be remotely controllable by means of control signals sent to the FIRE-NODE.
It will be seen in
As best shown in
It will be understood that the examples of functional modules in
It will be understood that in order to provide for data communications at a higher rate than can be supported on a data bus employing conductive connections, for example Ethernet, it is possible to provide optical connectors by providing at least one optical fiber output from the interface unit 142 and an optical fiber connector on at least one functional module.
It is noted that the base stations and functional modules have been described as utilizing both power and data. However, the functional modules need not require both, and the base stations and/or functional modules can have only power or data. In addition, the functional modules are separate and discrete devices with a housing that fully contains the functional electronic circuit devices therein. Accordingly, the functional devices can be removably mechanically attached to and removed from the functional module housing and removably mechanically and electronically attached to and removed from other functional modules and/or the interface. Thus, the base station is completely modular and can be readily reconfigured by mechanically and electronically adding (plugging in) and removing functional modules and/or the interface module, and/or by removably connecting the base station with other base stations. And, the base station forms a single contiguous and uninterrupted data path and a single contiguous and uninterrupted power path, amongst the functional modules, interface, and circuits.
In summary the invention provides a flexible arrangement for small cell base stations having functional modules implementing existing and future technologies rea zed as one or more vertical columns of functional modules cantilever mounted at their lower end, or as one or more horizontal rows of functional modules suspended from a catenary wire.
It is usual in mobile radio networks to transmit and receive signals having linear ±45□ slant polarization to improve the quality of the received signal and enhance the capacity of a network by taking advantage of polarization diversity. Base stations may also be equipped with multiple antennas to take advantage of MIMO operation (Multiple-Input, Multiple-Output), allowing further improvement in coverage and capacity, together with enhanced data rates.
A base station according to the invention may support both the transmission and reception of radio signals as well as cameras and sensors. The transmit signal direction is referred to in the following descriptions, but it is to be understood that all components and interfaces in the signal path support both transmitted and received signals.
Data circuits within a FIRE-NODE small cell base station may support duplex or virtual duplex, half-duplex or simplex data communication.
The invention provides for the integration of modules, each having one or more functionalities such as mobile radio, WiFi, camera or sensor. Hereinafter these will be referred to as functional modules.
A FIRE-NODE small cell base station according to the present invention can include:
(a) at least one electrical connection for the physical attachment of at least one incoming electricity supply;
(b) at least one physical communications interface, preferably using optical fiber or coaxial cable, supporting Ethernet or other selected protocol to communicate data to the FIRE-NODE, such data typically comprising user data, control data and management data, such interface being typically known as a backhaul connection;
(c) electrical circuit arrangements, comprising at least one power bus, providing for the distribution of power to all contained electrically powered circuits and devices;
(d) at least one interface to facilitate the extension of the said at least one power bus to extend the supply of power to electrically powered circuits and devices that may be installed within the FIRE-NODE, subsequent to its initial configuration, in the course of expansion of its communications or other facilities.
(e) electrical circuits and devices, comprising at least one data bus, providing bidirectional communication of data to different modules contained within the FIRE-NODE;
(f) at least one interface to facilitate the extension of the said at least one data bus to extend data connection to circuits and devices that may be installed within the FIRE-NODE subsequent to its initial configuration, in the course of expansion of its communications or other facilities;
(g) mechanical arrangements to facilitate the addition of further communications or other devices and the replacement of already installed communications or other devices, such arrangements preferably providing for the ability to add or exchange such devices with no interruption of the operation of other circuits or devices installed within the said FIRE-NODE (a capability known as hot-swapping);
(h) data processing and data storage circuits to enable intelligent management of services provided by the communications and other devices installed within the FIRE-NODE, such management comprising but being not limited to self-optimization, remote software download, remote configuration management, alarm and administration management.
The installed communications equipment in a FIRE-NODE may include electronics modules and antennas operating in different frequency bands assigned for the services provided, sourced from multiple vendors, using different communications or other technologies and serving users in different locations.
The antennas supporting radio connections from radio modules within the FIRE-NODE may be one or more of dipoles, crossed dipoles, patches, spirals, slots or other configurations dimensioned to operate at the required frequencies. The antennas may comprise arrays of such antennas arranged to provide radiation patterns suitable for the illumination of required service area and/or to support MIMO operation.
By way of an example a FIRE-NODE may comprise, within a single integrated physical housing, a cellular antenna array and beamforming unit, a WiFi antenna array and beamforming unit, a millimeter wave radio unit and antenna, a camera and a sensor unit, all connected to the fixed infrastructure by a single input power line and a single input optical signal line.
In some embodiments an optical fiber connection may be provided to at least one functional module comprised within the FIRE-Node low power base station,
It is further noted that the description and claims use several geometric or relational terms, such as circular, rounded, parallel, orthogonal, perpendicular, concentric, triangular, planar, and flat. In addition, the description and claims use several directional or positioning terms and the like, such as top, bottom, upper, lower, inner, outer, longitudinally. Those terms are merely for convenience to facilitate the description based on the embodiments shown in the figures. Those terms are not intended to limit the invention. Thus, it should be recognized that the invention can be described in other ways without those geometric, relational, directional or positioning terms. In addition, the geometric or relational terms may not be exact. For instance, walls may not be exactly perpendicular or parallel to one another but still be considered to be substantially perpendicular or parallel because of, for example, roughness of surfaces, tolerances allowed in manufacturing, etc. And, other suitable geometries and relationships can be provided without departing from the spirit and scope of the invention.
Within this specification, the various sizes, shapes and dimensions are approximate and exemplary to illustrate the scope of the invention and are not limiting. The sizes and the terms “substantially” and “about” mean plus or minus 15-20%, or in other embodiments plus or minus 10%, and in other embodiments plus or minus 5%, and plus or minus 1-2%. In addition, while specific dimensions, sizes and shapes may be provided in certain embodiments of the invention, those are simply to illustrate the scope of the invention and are not limiting. Thus, other dimensions, sizes and/or shapes can be utilized without departing from the spirit and scope of the invention.
Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without departing from spirit and scope of the invention. It will be appreciated that all features described herein are applicable to all aspects of the invention described herein. Each of the exemplary embodiments described above may be realized separately o combination with other exemplary embodiments. Numerous applications of the invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the specific examples disclosed or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
This application claims the benefit of U.S. Provisional Application Nos. 62/667,135, filed May 4, 2018, and 62/663,044, filed Apr. 26, 2018. The entire contents of those applications are incorporated herein by reference.
Number | Date | Country | |
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62667135 | May 2018 | US | |
62663044 | Apr 2018 | US |