Abstract:
A mast and radio assembly includes a mast formed from one or more hollow elongate members and a radio capsule housing a radio and antenna assembly, the radio capsule completely insertable into the mast for protection from environmental conditions.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/119,960, filed Feb. 24, 2015, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The technology of the present disclosure relates generally to wireless communications and, more particularly, to a mast assembly that houses a radio. In a typical configuration, the radio is used to establish wireless communications between a remotely deployed sensor and a node in a network. 
       BACKGROUND 
       [0003]    Remotely taking measurement readings from sensors and controlling equipment on farms and other outdoor commercial or industrial sites is often difficult due to the large distances involved and lack of infrastructure, such as wired communication lines and electric lines. 
       SUMMARY 
       [0004]    Disclosed is a mast and radio assembly for remote outdoor use. The mast houses a radio capsule that includes a radio and associated antenna for establishing wireless communications. The mast and a housing of the radio capsule protect the radio and associated antenna from the elements while providing a support to position the antenna at a desired height. The assembly, therefore, may be considered an integrated radio, antenna, radome and mast. The assembly is particularly well suited for outdoor environments where a radio is desired to establish communications between a sensor or piece of equipment and a node in communications network and/or where a radio is desired to provide network infrastructure, such as functioning as a node in a mesh network or other network infrastructure. The assembly is constructed to be easily installed in the ground and, if desired, removed and moved to another site. A battery compartment is easily accessed for changing a battery pack. In some embodiments, a sensor that is co-located with the mast and radio assembly is powered by the battery pack. The mast assembly, and radio and antenna therein, may be increased in height by adding extension sections. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a schematic diagram of a mast and radio assembly at an installation site with a sensor assembly. 
           [0006]      FIG. 2  is an exploded view of the mast and radio assembly without a radio capsule. 
           [0007]      FIG. 3  is an exploded view of an extension section of the mast and radio assembly. 
           [0008]      FIG. 4  is an exploded view of the radio capsule. 
           [0009]      FIG. 5  is a photograph of a front of a representative electronics module that forms part of the radio capsule. 
           [0010]      FIG. 6  is a photograph of a rear of the representative electronics module. 
           [0011]      FIG. 7  is a photograph of an alternative embodiment of a battery assembly for the mast and radio assembly. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0012]    Embodiments will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments. 
         [0013]    With initial reference to  FIG. 1 , schematically illustrated is a mast and radio assembly  10  that is installed in the ground  12  at an installation site together with a sensor assembly  14 . In the illustrated embodiment, the installation site is at a farm that grows crops and the sensor assembly  14  is a moisture sensor that is installed in the ground  12 . In other exemplary embodiments, the mast and radio assembly  10  may be employed at the “sub-master site,” at the “irrigation source,” and/or at the “moisture sensor assembly” as described in U.S. patent application Ser. No. 14/480,691 filed Sep. 9, 2014, the disclosure of which is incorporated herein by reference in its entirety. 
         [0014]    The mast and radio assembly  10  may be used in other operational contexts. The installation site may be in a location other than an agricultural farm such as, but not limited to, a livestock farm, an oil well head, a gas well head, a storage vessel, a campus setting, a rail yard, an industrial site, a wildlife monitoring station, or any other setting where wireless communications are desired. Also, the sensor assembly  14  may be any type of sensor, equipment or device. In other embodiments, the mast and radio assembly  10  is installed without an accompanying device and serves as a range-extending node in a wireless network. In one embodiment, the sensor assembly  14  may form part of the mast and radio assembly  10  (e.g., housed by the mast and radio assembly  10  or connected to a surface of the mast and radio assembly  10 ). 
         [0015]    The mast and radio assembly  10  includes a base tube  16 , one or more extension sections  18 , a radio capsule  20 , and a cap  22 . The base tube  16 , the extension section(s)  18  and the cap  22  form a mast that protects the radio capsule  20  from environmental conditions, such as dust, debris, rain, snow, ice, wind, sunlight, etc. The radio capsule  20  houses an antenna and an associated radio that are used to carry out wireless communications. In addition to protecting the antenna and radio, the mast and radio assembly  10  elevates the antenna to a desired height above the surface of the ground  12 , which may be beneficial to the wireless communications. 
         [0016]    With additional reference to  FIG. 2 , the base tube  16  is a hollow cylinder that is open at its top end  24 . A bottom end  26  may be open or closed. The bottom end  26  may be tapered or form a spike to facilitate insertion into the ground  12 . Alternatively, the bottom end  26  may slide or screw into another support element that is first inserted into the ground  12 . In another configuration, the bottom end  26  may form an auger to provide “self-drilling” functionality to the base tube  16 . In this case, a handle(s) or lever may be used to apply rotational force (e.g., torque) to the base tube  16 . The handle may attach to the base tube  16  (e.g., though a transverse hole or notch in the top end  24 ) or may fold out from the base tube  16 . 
         [0017]    In a typical installation, the base tube  16  is vertically inserted into the ground  12  to a depth sufficient to support the mast and radio assembly  10  in an upright configuration as shown in  FIG. 1  and without the use of cement or other securing structures. In one embodiment, a hole is established in the ground  12  to receive base tube  16 . The hole may be established with an auger, fence post digger, or other apparatus. In one embodiment, the hole is established with the same apparatus used to establish a hole for the sensor assembly  14 . In other embodiments, the mast and radio assembly  10  may be set in cement or secured to another structure. 
         [0018]    The base tube  16  includes a hole or aperture  28  in a sidewall  30  of the base tube  16  between the top end  24  and the bottom end  26 . The aperture  28  allows for passage of one or more cables into the mast and radio assembly  10 . In the illustrated embodiment, a cable  32  operatively connects the sensor assembly  14  and electronics in the mast and radio assembly  10 , as will be discussed in greater detail below. Excess length of the cable  32  may be stored in the base tube  16 . The excess length of cable  32  may be used to accommodate extending the height of the radio capsule  20  by adding one or more extension sections  18 , as will be discussed in greater detail below. 
         [0019]    In one embodiment, the base tube  16  has an inside diameter of 2.25 inches, an outside diameter of 2.5 inches, a sidewall 30 thickness of ⅛th inch and a length of 3.5 feet. The aperture  28  may be 1 inch in diameter and located equidistant between the ends  24 ,  26 . In this document, all sizes and dimensions are exemplary. 
         [0020]    In one embodiment, the aperture  28  is positioned to be below a surface  34  of the ground  12  when the base tube  16  is inserted into the ground  12 . This allows for at least a portion of the cable  32  extending between the sensor assembly  14  and the mast and radio assembly  10  to be buried (e.g., in a shallow trench). In other embodiments, all or some of the cable  32  extending between the sensor assembly  14  and the mast and radio assembly  10  may be above ground or may be contained in a conduit. 
         [0021]    In one embodiment, the base tube  16  may house the radio capsule  20 . This may be done, for example, at the early stages of the growing season when crops do not exceed the height of the top end  24 . In this case, the extension section  18  may be omitted and the cap  22  may be placed over the top end  24  to keep precipitation, dust and debris out of the base tube  16 . In one embodiment, a seal or gasket is present between the cap  22  and the base tube  16 . Also, in this configuration, the top end  24  may be elevated above the surface  34  of the ground  12  a sufficient distance to allow for an antenna (discussed below) contained within the base tube  16  to be above the surface  34  of the ground  12 . In some cases, however, the elevation of the top end  24  should be low enough to allow for farm equipment to drive over the installed base tube  16  and cap  22 . In one embodiment, the installed base tube  16  and cap  22  should not exceed a height of 18 inches. In other embodiments, the base tube  16  may be of a different height (e.g., extend from about 6 inches to about 40 feet above the surface  34  of the ground  12 . The base tube  16  may have an internal shoulder or other feature to hold the radio capsule  20  at a desired elevation above the surface  34  of the ground  12 . Alternatively, height of the radio capsule  20  relative to the ground  12  may be controlled by interaction of the radio capsule  20  with the upper end of the base tube  16 . In these embodiments, the base tube  16  and cap  22  serve as a mast and radome for a radio and antenna located within the radio capsule  20 . 
         [0022]    With continued reference to  FIGS. 1-3 , the extension section  18  includes an extension tube  36  and a coupling tube  38 , each of which are hollow cylinders that are open at each end. An upper end  40  of the coupling tube  38  fits in a lower end  52  of the extension tube  36  and is retained thereto with fasteners  44  (e.g., pins, plugs. rivets or screws inserted through mating holes). Alternatively, the extension tube  36  and the coupling tube  38  may be retained together with adhesive, may be of monolithic construction, or may mate by threaded connection between threaded ends of the tubes. 
         [0023]    In one embodiment, the extension tube  16  has the same inside diameter, outside diameter and wall thickness as the base tube  16 . For instance, the extension tube may have an inside diameter of 2.25 inches, an outside diameter of 2.5 inches, a sidewall  46  thickness of ⅛th inch and a length of 3 feet. In one embodiment, the coupling tube has an inside diameter of 2.0 inches, an outside diameter of 2.25 inches, a sidewall  48  thickness of ⅛th inch and a length of 2 feet. Again, all sizes and dimensions recited in this document are exemplary. 
         [0024]    The outside diameter of the coupling tube  38  and the inside diameter of the extension tube  36  are made so that the coupling tube  38  slides easily within the extension tube  36  but has little “play” that would allow for significant relative motion of the parts in a direction transverse to the longitudinal axis of the tubes  36 ,  38 , once assembled. Similarly, the outside diameter of the coupling tube  38  and the inside diameter of the base tube  16  are made so that the coupling tube  38  slides easily within the base tube  16  but has little “play” that would allow for significant relative motion of the parts in a direction transverse to the longitudinal axis of the tubes  36 ,  38 , once assembled. 
         [0025]    When fastened in the extension tube  36 , an upper portion of the coupling tube  38  is nested inside the extension tube  36 . The remainder of the coupling tube  38  (e.g., a lower portion thereof) extends out of the lower end  52  of the extension tube  36 . The lower portion of the coupling tube  38  may be inserted into the base tube  16  until the lower end  52  of the extension tube  36  comes to rest against the top end  24  base tube  16 . In the embodiment where the coupling tube  38  is about 2 feet long, about 1 foot of the coupling tube  38  may be inside the extension tube  36  and about 1 foot of the coupling tube  38  may be inside the base tube  16 . Additional fasteners may be used to secure the coupling tube  38  to the base tube  16 , but it is contemplated that the extension section  18  will remain suitably positioned on top of the base tube  16  by the force of gravity. Other securing techniques may be employed. For example, the coupling tube  38  and the base tube  38  may mate by threaded connection between threaded ends of the tubes. In one embodiment, one or more of the tubes  16 ,  36 ,  38 , or the radio capsule  20 , may be keyed or have a flat section so as to minimize rotational movement of the tubes  16 ,  36 ,  38  and/or radio module  20  relative to one another. In another embodiment, the top end  24  of the base tube  16  and the lower end  52  of the extension tube  36  have intermeshing configurations to minimize relative rotation with respect to one another. Exemplary intermeshing configurations include saw tooth patterns and crenelated patterns. Another securing technique includes using resilient detents, non-resilient detents or spring loaded buttons that are located on one tube element and that are captured by holes, recesses or slots on another one of the tube elements. For instance, radial pins may engage and lock into “L” shaped slots when axially slid and then rotated into a locked position. 
         [0026]    The cable  32  may be feed though the tubes  36 ,  38  of the extension section  18  (before or after assembly with one another and/or before or after mating of the extension section  18  with the base tube  16 ) and a connector  50  at an end of the cable  32  may be connected to a mating connector (discussed below) at a lower end  52  of the radio capsule  20 . Then, the radio capsule  20  is inserted into extension tube  36  at an upper end  54  thereof. The radio capsule  20  slides into the extension tube  36  until the lower end  52  of the radio capsule  20  rests against the upper end  40  of the coupling tube  38 . In other embodiments, downward movement of the radio capsule  20  may be limited by a shoulder inside the extension tube  36 , with fasteners, or by interaction of the radio capsule  20  with the upper end  54  of the extension tube  36 . 
         [0027]    With additional reference to  FIG. 4 , an outside diameter of the radio capsule  20  is primarily defined by a housing tube  56 . The outside diameter of the housing tube  56  and the inside diameter of the extension tube  36  are made so that the radio capsule  20  slides easily within the extension tube  36  but has little “play” that would allow for significant motion of the radio capsule  20  in a direction transverse to the longitudinal axis of the extension tube  36 , once assembled. In one embodiment, the housing tube  56  has an inside diameter of 2.0 inches, an outside diameter of 2.25 inches, a sidewall  58  thickness of ⅛th inch and a length of 2 feet. 
         [0028]    The cap  22  may be placed on the upper end  54  of the extension tube  36 . In one embodiment, the cap is a hollow cylindrical body that is open at a bottom end thereof and closed at a top end thereof. The inside diameter of the cap  22  may be sized so that the cap tightly fits over the outside diameter of the extension tube  36 , but is removable therefrom. In one embodiment, the cap  22  is secured to the extension tube  36  with fasteners or the cap  22  screws directly onto a threaded upper end of the extension tube  36 . In one embodiment, a seal or gasket is present between the cap  22  and the extension tube  36 . In the illustrated embodiment, a collar  60  is placed on or is integral with the outside of the extension tube  36  and serves as a positioner for the cap  22 . 
         [0029]    The base tube  16 , the extension tube  36 , the coupling tube  38 , the housing tube  56  and the cap  22  are preferably made from a non-ferrous, non-conducting and RF energy transparent material to allow RF signals to propagate through these parts without significant attenuation. An exemplary material for this purpose is fiberglass. As will be described, a radio and antenna assembly  62  may be housed in the housing tube  56  of the radio capsule  20 , which is, in turn, housed in the extension tube  36  that has its upper end  54  covered by the cap  22 . In this arrangement, the extension section  18 , the base tube  16  and cap  22  function as a mast to raise the height of the radio and antenna assembly  62  and function as a radome for the radio and antenna assembly  62  by protecting the radio and antenna assembly  62  from the elements. 
         [0030]    The height of the radio and antenna assembly  62  may be increased by adding an extension section  18 . This may be done by removing the cap  22  and then removing the radio capsule  20 . Next, the cable  32  is disconnected from the radio capsule  20 . The cable  32  is fed through an additional extension section  18  and reconnected to the radio capsule  20 . Then the portion of the coupling tube  38  extending from the extension tube  36  of the additional extension section  18  is inserted into the existing extension tube  36 . Then the radio capsule  20  is inserted into the additional extension tube  36  and the cap  22  is placed on the additional extension tube  36 . As many extension section  18  may be used as is desired so long as the height of the mast and radio assembly  10  remains structurally sound, including maintaining stability of the base tube  16  in the ground  12 . Each extension section  18  forming part of the mast and radio assembly  10  may be constructed in the same manner or in a manner similar to each other. Various extension sections  18  may be of different lengths. 
         [0031]    With reference to  FIGS. 4-6 , the radio capsule  20  will be described in greater detail. The radio capsule  20  includes the radio and antenna assembly  62  (e.g., electronics module) that is inserted into the housing tube  56 . In the illustrated embodiment, the radio and antenna assembly  62  includes a radio  64  and an antenna  66 . The radio  64  is embodied as a printed circuit board and associated electronic circuitry. Therefore, the radio  64  of the illustrated embodiment may be referred to as a “radio board” and may include components (e.g., control circuitry, processors, memory, etc.) that carry out functions in addition to wireless communications. The antenna  66  may be a low-profile antenna (e.g., a printed circuit board antenna) that is secured to a substrate  68  with adhesive. The substrate  68  may be made of plastic, such as ABS. An RF cable  70  may operatively couple the antenna  66  and the radio  64 , although the RF cable  70  is disconnected from the radio  64  in  FIGS. 5 and 6 . The antenna  66  may have other physical arrangements, but will typically be contained in the mast and radio assembly  10 . In other embodiments, at least a portion of the antenna  66  is located outside the mast and radio assembly  10  and is exposed to the elements. In this case, the antenna  66  or a cable connecting the antenna  66  to the radio  64  may protrude through the cap  22  or the extension tube  36 . 
         [0032]    In the illustrated embodiment, the radio and antenna assembly  62  is connected to retainer clips  72 . The clips  72  may be secured to the substrate  68  and the printed circuit board of the radio  64  with fasteners, such as machine screws and nuts. The clips  72  include wings that form circular sections and, when inserted into the housing tube  56 , contact an inner surface of the housing tube  56  to retain the radio and antenna assembly  62  in place. In the embodiment of  FIG. 4 , a first clip  72  is present at a lower end  74  of the radio  64 , a second clip  72  is present at an upper end  76  of the substrate  68 , and a third clip  72  may be present at the center of the radio and antenna assembly  62 . The third clip  72  may attach to both the substrate  68  and the radio  64  to hold the substrate  68  and the radio  64  in fixed relationship to one another. The clips  72  may include longitudinal passages or other features to aid in cable management. The first clip  72  at the lower end  74  of the radio  64  is omitted in  FIGS. 5 and 6 . 
         [0033]    A connector  78  for interfacing with the connector  50  of the cable  32  may be present at the lower end  74  of the radio  64 . Depending on cabling supplied with the sensor assembly  14 , the connector  50  may be field installed on the cable  32 . In other situations, an adapter may be interposed between the connector  50  and the connector  78  to establish an operative connection between the radio  64  and the sensor assembly  14 . In an alternative embodiment, the radio  64  may include a pigtail cable and connector that interfaces with the cable  32  and connector  50 . In still other embodiments, the radio  64  may include multiple connectors  78  or a bus for interfacing with multiple sensors or electronic devices. In other embodiments, the radio  64  may communicate wirelessly with the sensor assembly  14  or another nearby device, such as over a Bluetooth interface. 
         [0034]    A lower end cap  80  may cover a lower end of the housing tube  56 . The lower end cap  80  may include a passage  82  through which the connector  78  protrudes or is accessible. The end cap  80  may have a cylindrical portion that fits within the housing tube  56  and an end wall, as illustrated. The end cap  80  may secure to the housing tube  56  with resilient members  81  that are received in corresponding openings  83  in the housing tube  56 . Alternatively, the end cap  80  may be secured by friction fit, threaded connection, fasteners, coordinating indents and detents, or other appropriate structure. In one embodiment (e.g., as shown in  FIGS. 5 and 6 ), the lower end cap  80  is secured to the radio  64  with fasteners  84 , then the radio and antenna assembly  62  is inserted into the housing tube  56  via an open lower end  86  of the housing tube  56 . 
         [0035]    In one embodiment, the radio and antenna assembly  62  includes a source of power, such as a battery assembly  88 . The battery assembly  88  may connect to the radio  64  by way of a cable  89  ( FIG. 7 ). In one embodiment, the battery assembly  88  may supply operational power to the sensor assembly  14  by way of the cable  32  or a separate power cable. 
         [0036]    In the illustrated embodiment, the battery assembly  88  includes a battery pack  90  containing battery cells. The battery pack is contained in a sleeve  92 . The sleeve  92  may be part of or connected to the upper clip  72  and/or the substrate  68 . The sleeve  92  may be surrounded with a structure  94  that consumes space between the sleeve  92  and the housing tube  56  and minimizes excessive movement of the sleeve  92  and battery pack  90 . In one embodiment, the structure  94  is compliant. An exemplary compliant material for the structure  94  is foam, but the structure  94  may be made from more rigid material and/or combined with the sleeve  92 . 
         [0037]    An upper end cap  96  may cover an upper end  98  of the housing tube  56 . The upper end cap  96  may have a cylindrical portion that fits within the housing tube  56  and an end wall, as illustrated. Similar to the lower end cap  80 , the end cap  96  may secure to the housing tube  56  with resilient members that are received in corresponding openings in the housing tube  56 . Alternatively, the end cap  96  may be secured by friction fit, threaded connection, fasteners, coordinating indents and detents, or other appropriate structure. In one embodiment, the upper end cap  96  is secured to the radio and antenna assembly  62  with fasteners. 
         [0038]    The upper end cap  96  preferably includes a handle  98  that may be grasped by a hand of a user or a tool to facilitate removal of the radio capsule  20  from the extension tube  36  by pulling along the common longitudinal axis of the radio capsule  20  and extension tube  36 . 
         [0039]    From time to time, the battery pack  90  may be removed for recharging or for replacement with a charged battery pack  90 . To carry out this process, a user may remove the cap  22  and then at least partially remove the radio capsule  20  from the extension section  18 . Next, the cap  96  may be removed and the battery pack  90  is removed from the sleeve  92 , which disengages a physical connection between electrical contacts of the battery pack  90  and mating electrical contacts inside the sleeve  92 . The mating electrical contacts inside the sleeve  92  may be part of an electrical pathway between the battery pack  90  and the radio  64 . 
         [0040]    A charged battery pack  90  or the original battery pack  90 , following recharging, may be inserted into the sleeve  92  and physical connection between electrical contacts of the battery pack  90  and mating electrical contacts inside the sleeve  92  may be re-established. Then the cap  96  may be placed back on the housing tube  56 . In one embodiment, the cap  96  includes a member or has sufficient thickness when the radio capsule  20  is assembled to force the contacts of the battery pack  90  to remain in physical connection with the contacts in the sleeve  92 . In other embodiments, the contacts of the battery pack  90  and the contacts in the sleeve  92  are male and female components of mating connectors to maintain connection between the sets of contacts. Once the cap  96  is returned to its position, the radio capsule  20  may be returned to its position in the extension section  18  and the cap  22  may be returned to its position on the extension section  18 . In other embodiments, the battery pack  90  may be removed and replaced without removing the radio capsule  20  from the extension section  18 . 
         [0041]    The clips  72 , cap  80 , cap  96  and sleeve  92  may be made from a suitable plastic material, such as ABS. 
         [0042]      FIG. 7  shows another embodiment of the battery assembly  88 . In this embodiment, the battery pack  90  is secured to a lower side of the cap  96 , such as with adhesive, hook and look fastener, screws, or another type of fastener. In this embodiment, the sleeve  92  and the structure  94  may be omitted. In this embodiment, leads  91  that extend from the battery pack  90  connect to the cable  89  via mating connectors as shown. In one embodiment, a spacer is inserted in the housing tube  56  between the battery pack  90  and the upper end of the radio and antenna assembly  62 . 
         [0043]    Since the battery pack  90  is secured to the cap  96 , the battery pack  90  may be removed from or put into the housing tube  56  by removing the cap  96  from the housing tube  56  or connecting the cap  96  to the housing tube  56 , respectively. To replace the battery pack  90 , the cap  96  and battery pack  90  may be removed from the housing tube  56 , the leads  91  may be disconnected from the cable  89 , the battery pack  90  may be removed from the cap  96 , a new or recharged battery pack  90  may be secured to the cap  96 , the leads  91  may be connected to the cable  89 , and the cap  96  with battery pack  90  may be reconnected with the housing tube  56 . In another embodiment, the cap  96  and battery pack  90  are not easily separable from one another. In this case, replacement of the battery pack  90  may include replacement of the cap  96 . 
         [0044]    The radio and antenna assembly  62  may be configured to operate over cellular bands and protocols, WiFi bands and protocols, Bluetooth bands and protocols, and/or any other suitable bands and protocols for carrying out the communication functions of the radio and antenna assembly  62 . Additionally, the radio  64  may include functionality for interfacing with and processing information from the sensory assembly  14  or any other connected electronic device. 
         [0045]    As will be appreciated, various modifications may be made to the mast and radio assembly  10 . For example, the mast and radio assembly  10  may be used to support and/or protect additional items. One exemplary additional item that may be supported by the mast and radio assembly  10  is a solar panel used to recharge the battery pack and/or supply operational power. The solar panel may be fixed relative to the mast and radio assembly  10  or may be configured to track the location of the sun. In an embodiment that includes a solar panel, it may be desirable to include features that minimize rotation of the tube elements relative to one another so that wind acting on the solar panel does not cause rotation of the tube elements relative to one another and turn the solar panel away from the sun. Other additional items that may be supported by the mast and radio assembly  10  include, but are not limited to, monitoring equipment, such as weather monitoring equipment for monitoring temperature, wind speed, barometric pressure, precipitation, etc. 
         [0046]    Although certain embodiments have been shown and described, it is understood that equivalents and modifications falling within the scope of the appended claims will occur to others who are skilled in the art upon the reading and understanding of this specification.