Patent Publication Number: US-2019177995-A1

Title: Tower assembly with ballast receiving base

Description:
This application claims priority benefit to U.S. provisional application Ser. No. 62/328,864, filed Apr. 28, 2016. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a tower assembly, for example a communications tower supporting an antenna thereon, in which a base of the tower is self-supported on a ground surface using ballast material supported on the base, and more particularly the present invention relates to a tower assembly having a base supporting a plurality of ballast receptacles thereon spaced radially outward from a central tower coupler that pivotally supports the bottom end of the tower frame thereon such that the tower frame can be erected using lifting equipment operatively connected between the tower base and the tower frame. 
     BACKGROUND 
     Towers structures are commonly used for supporting a variety equipment thereon including communications antennas, lighting, signage, wind turbines, solar panels, and various transmission devices for example. To maintain the tower supported in a stable upright configuration, it is common to employ a foundation penetrated into the ground to resist overturning forces. The foundation typically includes one or more types of piles penetrated into the ground including concrete piles, screw piles and the like for example. Because of the various conditions of the ground into which a foundation must be penetrating, the design requirements of the foundation may vary considerably between different installation sites which can involve costly and time consuming design requirements for each installation site. Even when a standard foundation design is employed for use in different site conditions, the installation of piles including pouring of concrete can be costly and time consuming, particularly in remote sites. 
     U.S. patent applications 2014/10059957 by Stark and U.S. 2015/0197957 by Anderson, each disclose an example of a tower foundation structure which does not require penetration into the ground so as to be more suited to a variety of different installation conditions. In each instance a large platform is required to support ballast material thereon onto which the tower must be subsequently erected. The location of the ballast receiving platform directly adjacent to the base of the tower requires a very large amount of ballast to be supported thereon to resist overturning forces. Furthermore, the raising of the tower onto the platform typically requires use of costly lifting equipment such as a crane or boom truck which is costly and may trouble accessing to the tower site in some remote locations. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention there is provided a tower assembly comprising: 
     a support tower; and 
     a tower base for being supported on a ground surface, the tower base comprising:
         i) a tower coupler for supporting a bottom end of the support tower thereon such that the support tower extends longitudinally upward from the tower base;   ii) a plurality of frame members extending radially outward from the tower coupler; and   iii) a ballast receptacle supported on each frame member at a location spaced radially outward from the tower coupler for receiving ballast material therein.       

     The arrangement of radially oriented frame members extending between a central tower coupler and respective ballast receptacles allows for a more efficient use of ballast material to support the tower in a foundationless manner on a ground surface. The arrangement of the frame members also provides a frame assembly which can be readily assembled from modular units for low cost and efficient transport and subsequent assembly of the tower on site. 
     When the support tower comprises three columns arranged in a triangular configuration relative to one another, preferably the plurality of frame members of the tower base comprise three frame member extending radially outward from the three columns of the support tower respectively. 
     Preferably the tower base is a modular assembly in which each frame member is connected between the tower coupler and the respective ballast receptacle using threaded fasteners such that each frame member is readily separable from the tower coupler and the respective ballast receptacle. 
     When the tower assembly further comprises a control box housing telecommunications equipment therein connected to an antenna on the support tower, the control box is preferably supported at a distal end of one of the frame members opposite from the tower coupler. 
     Preferably the tower base is adapted to be supported on the ground surface in a non-penetrating manner. Accordingly, when using a plurality of guy-wires connected between the support tower and the tower base, preferably these guy-wires are the only guy-wires connected to the support tower. 
     The tower coupler is preferably pivotally mounted on the frame assembly such that the support tower is pivotal about a generally horizontal axis between an assembly position in which the support tower extends longitudinally outward from the tower base along the ground surface and a raised position in which the support tower extends longitudinally upward from the tower base. 
     According to a second aspect of the present invention there is provided a tower assembly comprising: 
     a support tower; and 
     a tower base comprising:
         i) a plurality of frame members defining a frame assembly for being supported on a ground surface;   ii) at least one ballast receptacle supported on the frame assembly for receiving ballast material therein; and   iii) a tower coupler supported on the frame assembly for supporting a bottom end of the support tower thereon, the tower coupler being pivotally mounted on the frame assembly such that the support tower is pivotal about a generally horizontal pivot axis between an assembly position in which the support tower extends longitudinally outward from the tower base along the ground surface and a raised position in which the support tower extends longitudinally upward from the tower base.       

     According to a further aspect of the present invention there is provided a method of erecting a tower assembly comprising: 
     providing a support tower; 
     providing a tower base including i) a frame assembly, ii) at least one ballast receptacle supported on the frame assembly, and iii) a tower coupler supported on the frame assembly; 
     supporting the frame assembly on a ground surface; 
     filling said at least one ballast receptacle with ballast material; 
     coupling a bottom end of the support tower to the tower coupler of the tower base such that the support tower is pivotal about a generally horizontal pivot axis between an assembly position in which the support tower extends longitudinally outward from the tower base along the ground surface and a raised position in which the support tower extends longitudinally upward from the tower base; 
     pivotally raising the support tower from the assembly position to the raised position; and 
     fixing the support tower to the tower base in the raised position. 
     The pivotal connection of the support tower to the tower base allows lifting equipment to be connected directly between the support tower and the tower base without the need for auxiliary lifting equipment such as a crane or boom truck being required. The assembly and raising of the tower on site can thus be accomplished efficiently and at low cost. 
     When the plurality of frame members comprise three frame members extending radially outwardly from the tower coupler to respective ballast receptacles spaced radially outward from the tower coupler at evenly spaced positions in a circumferential direction about the tower coupler, preferably the tower coupler supports the support tower to extend from the tower coupler diametrically opposite from one of the three frame members in the assembly position. 
     The support tower may be raised using an additional lifting kit which is temporarily attached to the tower assembly during lifting. The lifting kit typically includes a lifting strut supported relative to the support tower to extend radially outward from a longitudinal axis of the support tower, and a winch for lifting the support tower from the assembly position to the raised position. Preferably a winch cable of the winch is operatively connected between the lifting strut and the support tower. 
     Preferably the lifting strut is supported to extend radially outward from the pivot axis of the tower coupler. 
     Typically, a tension member, such as an additional cable, is supported under tension between the lifting strut (at a location where the winch cable is connected) and the support tower at a central location along a length of the support tower. 
     Once the support tower is erected into the raised position, the method preferably includes coupling threaded fasteners between the support tower and the tower base to fix the support tower to the tower base in the raised position. 
     Preferably the support tower is assembled from a plurality of modular tower sections in the assembly position of the support tower relative to the tower base prior to pivotally raising the support tower from the assembly position to the raised position. 
     One embodiment of the invention will now be described in conjunction with the accompanying drawings in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the tower assembly; 
         FIG. 2  is a top plan view of the tower assembly; 
         FIG. 3  is a side elevational view along the line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a rear elevational view along the line  4 - 4  of  FIG. 2 ; 
         FIG. 5  is a perspective view of the tower base with the tower coupler shown in the assembly position of the tower, but with the tower shown removed; 
         FIG. 6  is a top plan view of the tower base in the assembly position; 
         FIG. 7  is a side elevational view of the tower base in the assembly position along the line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a rear elevational view of the tower base in the assembly position along the line  8 - 8  of  FIG. 6 ; 
         FIG. 9  is a perspective view of the tower base with the tower coupler shown in the raised position of the tower, but with the tower shown removed; 
         FIG. 10  is a side elevational view of the tower base in the raised position; 
         FIG. 11  is a perspective view of a bottom side of the central frame portion of the tower base in the raised position of the tower, but with the tower shown removed; 
         FIG. 12  is a bottom plan view of the central frame portion of the tower base in the raised position; 
         FIG. 13  is a side elevational view of the central frame portion of the tower base in the raised position; 
         FIG. 14  is a perspective view of the tower in the assembly position with the lifting kit supported thereon; 
         FIG. 15  is a side elevational view of the tower in the assembly position with the lifting kit supported thereon; and 
         FIG. 16  is a side elevational view of the tower with the lifting kit supported thereon in an intermediate position of the tower between the assembly position and the raised position. 
     
    
    
     In the drawings like characters of reference indicate corresponding parts in the different figures. 
     DETAILED DESCRIPTION 
     Referring to the accompanying figures there is illustrated a tower assembly generally indicated by reference numeral  10 . The tower assembly is particularly suited for supporting various types of equipment in an elevated manner above a ground surface. In the illustrated embodiment, the tower is adapted for supporting a communication antenna  12  thereon and further includes a control box  14  housing electronic communications equipment therein which is connected to the antenna so as to enable communication among a plurality of towers to function as a wireless communications network. 
     The tower assembly  10  generally includes i) a tower base  16  for being supported on the ground surface, and ii) a support tower  18  including a tower frame which is elongate in a longitudinal direction between a bottom end for being supported on the tower base  16  and an opposing top end supporting a communication antenna  12  thereon. 
     The tower frame of the support tower comprises three columns  20  spanning the full height of the support tower in a triangular configuration relative to one another. The horizontal spacing between the columns is gradually reduced from the bottom end to the top end. A plurality of supporting struts (not shown) are interconnected between the columns  20  to create a trust structure of the tower frame. Suitable brackets  22  protrude radially outward from the support frame at vertically spaced positions in proximity to the top end of the tower for supporting the communication antennas  12  thereon. 
     Each column  20  includes a foot plate  24  mounted at the bottom end thereof. The three foot plates  24  lie in a common plane perpendicular to the longitudinal axis of the support tower  18  and include fastener apertures therein for securement to the tower base as described in further detail below. 
     The tower base  16  generally includes i) a frame assembly having a central frame portion  26  and three frame members  28  mounted two extend radially outward from the central frame portion at evenly spaced positions in the circumferential direction, ii) a tower coupler  30  supported on the central frame portion  26  to couple the support tower to the frame assembly of the tower base, and iii) three ballast receptacles  32  supported at the outer ends of the three frame members  28  respectively for receiving ballast material therein. 
     The central frame portion  26  includes an upper support plate  34  which is generally triangular in shape so as to be similarly shaped and sized to the triangular pattern formed by the three foot plates  24  of the tower frame. Three mounting plates  36  extend vertically downwardly from each of the three corners of the triangular upper support plate  34  such that each mounting plate  36  is tangentially oriented relative to a central vertical axis of the upper support plate. More particularly each of the mounting plates  36  is perpendicular to the upper supporting plate and perpendicular to a radial axis extending from the central axis of the upper support plate. 
     A side wall  38  depends vertically downward from each of the three side edges of the upper support plate  34  such that each side wall  38  is connected between the respective adjacent pair of the mounting plates  36  at the corners of the triangular upper support plate  34 . The side walls  38  extend downwardly by approximately half of the overall height of the mounting plates  36  at the corners of the upper support plate. 
     Additional structural support is provided by three brace plates  40  mounted below the upper support plate  34  in perpendicular relation to the upper support plate. Each brace plate  40  is joined to the other brace plates along an inner edge at the central axis of the upper support plate and extends radially outward towards an outer edge joined in perpendicular relation to the inner surface of a respective one of the mounting plates  36 . 
     A lower plate  42  extends horizontally inward from a bottom end of each mounting plate  36  to be joined to the bottom edge of the corresponding brace plate  40  in proximity to the outer ends thereof for added structural support. 
     The three frame members  28  of the frame assembly of the tower base each comprise an I-beam extending along the full length thereof between an inner end  44  and an outer end  46  of the beam. Each frame member thus comprises a top flange, a bottom flange, and a web connected between the top and bottom flanges in the usual manner of an I-beam. Each frame member further includes an end plate  48  connected between the top and bottom flanges of the beam at each of the opposing inner and outer ends. The end plates  48  of each frame member are oriented transversely to the longitudinal direction of the respective frame member and are parallel to one another. 
     The end plates  48  at the inner end of each frame member are sized and shaped for mating abutment with a respective one of the mounting plates  36  of the central frame portion. Fastener apertures are provided in the inner end plate in alignment with corresponding fastener apertures in the respective mounting plate  36  of the central frame portion to permit threaded fasteners to secure the frame members to the central frame portion in a modular manner which permits subsequent disassembly as may be desired. 
     The end plates are oriented non-perpendicularly to the longitudinal direction of the respective frame member such that bolting the inner end plate flat against the respective mounting plate of the central frame portion results in the longitudinal axis of the frame member extending radially outward at a downward slope from the inner end to the outer end of the frame member in the assembled configuration. When all three frame members are assembled, the three ballast receptacles function as footings of the overall tower base for engaging the ground and the central frame portion is supported to be spaced above the ground relative to the elevation of the three ballast receptacles. 
     Each ballast receptacle  32  includes a rectangular floor  50  defining the bottom of the receptacles which is suitable for abutment flat against an upper surface of the ground. An inner end wall  52  extends perpendicularly upward from an inner edge of the rectangular floor which includes a pattern a bolt apertures therein for alignment with corresponding bolt apertures within the corresponding end plate  48  at the outer end of a respective one of the frame members of the tower base. The bolt apertures permit threaded fasteners to secure the frame members to the ballast receptacles respectively in a modular manner which permits subsequent disassembly as may be desired. 
     Each ballast receptacle  32  further includes two side walls  54  extending perpendicularly upward from opposing side edges of the rectangular floor  50  so as to be parallel and spaced apart from one another with the inner end wall being connected between inner edges of the two side walls respectively. A brace arm  56  is also connected between the two side walls  54  at an opposing outer and of the ballast receptacle at a location spaced above the floor  50  at the top edges of the two side walls. The top side of the ballast receptacle remains open to readily permit ballast material, for example rocks or concrete blocks and like to be inserted into the receptacle through the open top end. Similarly, the outer end of the receptacle, opposite the inner end wall fastened to the respective frame member, also remains open for ease of loading ballast material into the receptacle. 
     The tower coupler  30  comprises a pivot plate  58  which is generally triangular in shape and sized similarly to the upper support plate  34  of the central frame portion such that the pivot plate is suitably arranged for alignment with and flat engagement upon an upper surface of the upper supporting plate in a finished assembled configuration of the tower. The pivot plate  58  is coupled along one of the three edges of the triangular shape of the plate to a corresponding edge of the triangular upper support plate  34  by a hinge pin  60  which is horizontally oriented and parallel to the corresponding side edges of the plates. 
     The pivot plate  58  further includes an upright flange  62  protruding perpendicularly upward from the plate when the plate is horizontally oriented along the edge of the pivot plate corresponding to the hinge coupling. The other two edges of the triangular pivot plate  58  include a depending flange  64  formed thereon which depends downwardly when the pivot plate  58  is horizontally oriented against the upper surface of the support plate  34 . The pivot plate  58  of the tower coupler is slightly larger in dimension than the triangular support plate  34  to allow the depending flanges to extend downwardly alongside the outer sides of the side walls  38  of the central frame portion of the base. 
     The hinge pin  60  is coupled to the pivot plate  58  by three hinge plates which are axially spaced apart at fixed positions along the outer side of the upright flange  62  and three corresponding hinge plates which are axially spaced apart along the corresponding edge of the upper support plate  34  in fixed relation thereto. The hinge pin  60  which defines the pivot axis of the pivot plate relative to the upper support plate extends through corresponding pivot apertures in each of the hinge plates. 
     Each foot plate  24  at the bottom of the tower frame includes three fastener apertures therein which are suitably aligned with corresponding fastener apertures in the pivot plate  58 . Suitable threaded fasteners can thus be used to bolt each foot plate to the pivot plate  58  of the tower coupler such that the tower is pivotal together with the pivot plate  58  about the pivot axis of the hinge pin  60  between an assembly position in which the pivot plate extends upward from the pivot axis so that the tower coupled thereto extends generally horizontally along the ground surface, and a raised position in which the pivot plate  58  is generally horizontally oriented against the upper surface of the upper support plate  34  so that the tower extends longitudinally upward in alignment with the central vertical axis of the central frame portion of the tower base. 
     The upper support plate  34  includes one fastener aperture  66  in alignment with the outermost one of the three fastener apertures for each foot plate  24  of the tower frame. A common threaded fastener is thus adapted to be received through each fastener aperture  66  for collectively fasting together the upper support plate  34 , the pivot plate  58 , and a respective one of the foot plates  24 . 
     The upper support plate  34  also includes two access holes  68  associated with each foot plate  24  such that the two access holes are aligned with the two other fastener apertures of the respective foot plate  24  which do not align with a corresponding fastener aperture  66  in the upper plate. The access holes  68  are larger in dimension than the heads of the fasteners used at the other fastener locations of the foot plate. In this manner suitable threaded fasteners can be used to secure the foot plates  24  to the pivot plate  58  while the pivot plate remains in the assembly position of the tower. As the tower is subsequently raised, the threaded fasteners which are already used to secure the foot plates  24  to the pivot plate  58  are not in interference with the upper plate by being axially aligned with and received through the corresponding access holes  68 . 
     The assembly of the tower described herein typically involves transporting the central frame portion  26  of the tower base, the frame members  28  of the tower base, the ballast receptacles  32 , and various modular sections of the support tower frame as separate modular components to the site of the tower. The tower base is initially assembled using threaded fasteners to connect the frame members  28  between the central frame portion  26  and respective ones of the ballast receptacles  32 . The pivot plate of the tower coupler  30  on the tower base can then be pivoted into an upright orientation corresponding to the assembly position of the tower so that the modular tower sections can be assembled to one another to form the tower frame together with the bottom end of the tower frame being fastened to the pivot plate of the tower coupler. 
     Prior to pivotally raising the support tower, ballast material is placed in each of the ballast receptacles. Suitable lifting equipment can then be used to raise the tower into the raised position. Once in the raised position, the third threaded fastener associated with each foot plate  24  is used to fasten the foot plates through the pivot plate  58  to the corresponding aperture  66  of the underlying upper support plate  34  of the central frame portion of the tower base to fix the tower frame relative to the tower base in the raised position. 
     In the preferred embodiment, the lifting equipment used to raise the tower comprises a lifting kit which is temporarily attached to the tower assembly only during lifting of the tower from the assembly position to the raised position. The lifting kit generally includes a lifting strut  70  comprised of two arms  72  which are pivotally connected at respective inner ends of the arms to axially opposed ends of the hinge pin  60  such that the lifting strut is pivotal about the hinge pin together with the tower frame. Opposing outer ends of the two arms  72  are coupled to one another. A tension member  74 , for example a cable, is connected under tension between the outer ends of the two arms  72  of the lifting strut  70  and the tower frame at a central location along the length of the tower frame between the top and bottom ends thereof. 
     A winch  76  is operatively connected between the tower base and the support tower through the lifting strut  70 . More particularly the winch  76  includes a winch cable  78  having a first end secured to a drum onto which the cable is arranged to be wound and which is supported on the frame member  28  of the tower base that is diametrically opposite from the tower frame in the assembly position relative to a central axis of the central frame portion. An opposing second end of the winch cable is secured to the outer end of the lifting strut. The lifting strut is thus supported to extend generally radially outward from the longitudinal axis of the tower frame, and more particularly to extend radially outward from the pivot axis of the hinge pin. 
     The winch is secured to the corresponding frame member  28  at the location of the connection to the ballast receptacle towards the outer end of the frame member. A radial length of the strut is near to the length of the frame member such that the outer end of the strut substantially aligns with the outer end of the frame member locating the winch thereon. Winding the cable  78  onto the drum of the winch causes the outer end of the lifting strut to be drawn towards the outer end of the corresponding frame member supporting the winch thereon while the tower frame pivots together with the strut by the tension through the tension member  74  until the tower is erected. Once erected, the final fasteners are inserted through the corresponding fastener apertures  66  in the upper support plate  34  to fix the tower frame in the raised position as described above. The lifting strut and winch can be removed once the tower is fixed in the raised position. 
     Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.