TOWER FOUNDATION GUIDE ROD NUT

Abstract

A tower foundation (10) has a base slab (11), pillar slabs (12), and a crown stab (13), all of which are made of precast concrete structures. The slabs are all retained in position by steel guide rods (15) that extend upwardly from the base slab. The guide rods have externally threaded lower ends (16) configured, to receive internally threaded guide rod mounting nuts (17) which have a metal mounting plate (20) with a guide rod hole (21) therethrough, a main body portion (22) welded to the mounting plate and having a threaded channel (23) therethrough, and a sealing plate (24) coupled to bottom of the main body portion through a peripheral weld (25) so as to seal the bottom opening of the threaded channel.

Description

TECHNICAL FIELD

This invention relates to foundation slabs, and particularly to the threaded guide rod nuts utilized in foundations made of precast concrete slabs.

BACKGROUND OF THE INVENTION

Today there exists a vast number of towers, such as cellular telephone towers, railroad communication tower utilizing microwave, radio and satellite communications, and tilt-down towers, being erected across the country. Each tower includes a foundation which is typically embedded within the ground to prevent the tower for toppling over.

In the past, these foundations have been constructed by merely digging a hole in the ground and filling the hole with concrete to which the upright towers is anchored. This has been costly in that it requires that mixed concrete in fluid form be transported to each site, requires a curing time to pass before the next step of the process can be complete, thereby slowing the construction process and increasing costs, and requires a time or inspection delay between construction events which can cause days of delays to occur.

More recently, foundations have been made of a series of precast concrete components. The precast concrete components include large slabs with holes therethrough through which guide rods extend that coupled the slabs together. The bottommost slab includes a threaded guide rod mounting nut into which each guide rod is threadably mounted. These guide rod mounting nuts may include a small bar welded across the bottom of the nut to limit the travel of the bar. However, these guide rod mounting nuts and their corresponding guide rods tend to corrode over time due to the leaching of elements from the concrete, especially in the area of the threads of each.

Accordingly, it is seen that a precast tower foundation guide rod mounting nuts that overcomes or alleviates the just described problems is needed. It is to the provision of such therefore that the present invention is primarily directed.

SUMMARY OF THE INVENTION

A tower foundation base slab comprises a concrete body portion having a top surface, a bottom surface opposite the top surface. The base slab also includes a plurality of guide rod mounting nuts embedded within the concrete body portion, each guide rod mounting nut having a mounting plate with a guide rod hole therethrough, a main body portion having an internally threaded channel extending generally vertically between a top opening and a bottom opening, the main body portion being positioned below the mounting plate and having the internally threaded channel aligned with the mounting plate guide rod hole, and a sealing plate coupled to the main body portion opposite the mounting plate completely sealing the channel bottom opening. The tower foundation base slab also has a plurality of guide rod mounting holes extending between the mounting plate guide rod hole and the concrete body portion top surface.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a tower foundation embodying principles of the invention in a preferred form.

FIG. 2 is a top view of the crown slab of the foundation of FIG. 1.

FIG. 3 is a cross-sectional view of the crown slab of a portion of the foundation of FIG. 1.

FIG. 4 is a perspective view of the compression washer assembly of the tower foundation of FIG. 1.

FIG. 5 s a cross-sectional view of a portion of the base slab of the foundation of FIG. 1.

FIG. 6 is a perspective view of a guide rod mounting nut of the foundation of FIG. 1.

DETAILED DESCRIPTION

With reference next to the drawing, there is shown a tower foundation 10 of the present invention in a preferred form. The foundation here has a base or bottom slab 11, a plurality of pillar or middle slabs 12, and a crown or top stab 13, all of which are made of precast concrete structures. The base slab 11, pillar slabs 12 and crown slab 13 are all retained in position by four steel guide rods 15 that extend upwardly from the base slab 11. The four guide rods 15 have externally threaded lower ends 16 configured to be received within internally threaded guide rod mounting nuts 17 which are embedded within the bottom slab 11. The four guide rods 15 also have externally threaded upper ends 18 configured to be received within internally threaded foundation securing nuts 19. Each guide rod mounting nut 17 has a metal mounting plate 20 with a guide rod hole 21 therethrough which is aligned with a base slab guide rod mounting hole 27. The guide rod mounting nut also has a threaded main body portion welded to the mounting plate 20 and having a threaded channel 23 therethrough axially or longitudinally aligned with the mounting plate guide rod hole 21 and configured to threadably mate with the lower end 16 of the guide rods, and a sealing plate 24 coupled to bottom of the main body portion 22 through a peripheral weld 25 so as to completely seal the bottom opening of the threaded channel 23.

The two pillar slabs 12 are generally X-shaped (four legs 12′) and rest upon the base slab 11. The pillar slabs 12 have four guide rod mounting holes 30 extending therethrough positioned to be aligned with the guide rods 15. The pillar slabs 12 are mounted on the four guide rods 15 atop the base slab 11.

Finally, the crown slab 13 is mounted atop the pillar slabs 12. The concrete crown slab 13 has a body portion with four guide rod mounting holes 32 extending therethrough through which the guide rods 15 extend. The crown slab also includes four unshown eye bolts extending from eye bolt mounting holes and embedded inserts within the top surface.

The crown slab 13 also has four compression washer assemblies 35 partially embedded therein. Each compression washer assembly 35 includes a metal pressure plate, main. plate, or washer 36 and a pair of oppositely disposed mounting or anchor legs 37 mounted to the pressure washer 36. The pressure washer 36 has a central mounting hole 38 coaxially aligned with the crown slab guide rod mounting holes 32 through which the guide rod extends. The pressure washer 36 has a top surface 39 which is positioned generally coplanar or flush with the top surface 40 of the crown slab and therefore exposed from the top. The anchor legs 37 are embedded within the crown slab to provide reinforcement and stability.

With this construction, the slabs 11, 12 and 13 are assembled with the guide rods extending through each slab's axially aligned mounting holes (32, 30 and 27) with the guide rods' lower end 16 extending through the guide rod hole 21 of the mounting plate 20 and threaded into the threaded channel 23 of the main body portion 22. The guide rods' upper ends 18 extending past the top surface 40 of the crown slab 13 so as to receive the foundation securing nuts 19. The sealing plate 24 of the guide rod mounting nuts 17 also acts as a stop to prevent the guide rods from extending completely through the guide rod mounting nuts should it be overly threaded into the main body portion 22, which prevents the guide rods from punching through the concrete below the guide rod mounting nuts 17. The positioning of the main body portion 22 below the mounting plate 20 causes any upward pulling force upon the guide rod mounting nuts to be dissipated throughout the mounting plate 20 while forcing the main body portion against the mounting plate to prevent separation therebetween. The larger size and surface area of the mounting plate with respect to the main body portion also dissipates the force over a larger area.

This construction of the foundation allows the weight of the tower to be dissipated through the pressure washer 26 and into the rest of the foundation, rather than being loaded upon the guide rods and solely to the base of the foundation. The threaded foundation securing nuts 19 are then threaded onto the rods upper end 18 to a position wherein they are in direct contact with and bear tightly against the top surface 39 of the pressure washer 36. As such, the guide rod foundation securing nuts 19 bear against a solid metal plate like structure. Thus, the guide rod tower mounting nuts no longer bears against concrete which is susceptible to chipping or wearing due to vibrations or other types of movement. The elimination of the concrete wearing problem enables the tower mounting nuts r be better secured and the tower foundation to be more rigid and therefore safer in initial construction as well as over an extended period of time.

The threaded upper ends 18 of the guide rods extend past the top surface 40 of the crown slab 13. A tower T, or the like, is then coupled to the upper end 18 and secured in place on each rod by a pair of threaded tower mounting nuts 42. The relative positions of the tower mounting nuts 42 along the guide rod 15 may be adjusted to level the tower.

Once the foundation is placed in the ground and the dirt is packed tightly around the foundation the dirt is pressed tightly against the sidewalls of the pillar slabs.

Typically, the foundation of FIG. 1 is used to support cellular towers or the like, but may be used for any type of tower, signage, signal or other device, and thus the term tower and/or tower foundation is utilized herein as a generic term for any pole, vertical structure, or tower-like structure mounted to the foundation. As such, the term tower foundation is not meant to be a limitation, but merely a description of one use of structure used in conjunction with the foundation.

It should be understood that any number and peripheral shape of pillar slabs may be utilized with the present invention, the number and size of slabs depends on the size and weight of the slabs and on the size, height and weight of the tower coupled thereto. Also, it should be understood that the base and crown slabs may also be configured to having tapered sidewalls.

The foundation slabs may b manufactured in the convention fashion, such as the method described in U.S. Pat. No. 6,257,489 which is incorporated herein by reference.

It should be understood that the sealing of the guide rod mounting nut's bottom opening prevents elements which leach from the concrete from entering the threaded channel 23 of the guide rod mounting nuts. This sealing of the threaded channel resists corrosion of the metal guide rods and the threads of the metal guide rod mounting nuts 17 and their resulting weakening therefrom.

It thus is seen that a tower foundation is now provided that overcomes problems long associated with those of the prior art. It should be understood however that many modifications, additions and deletions may be made to the embodiments specifically described without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. A tower foundation base slab comprising,

a concrete body portion having a top surface, a bottom surface opposite said top surface;

a plurality of guide rod mounting nuts embedded within said concrete body portion, each guide rod mounting nut having a mounting plate with a guide rod hole therethrough, a main body portion having an internally threaded channel extending generally vertically between a channel top opening and a channel bottom, opening, said main body portion being positioned below said mounting plate and having said internally threaded channel aligned with said mounting plate guide rod hole, and a sealing plate coupled to said main body portion opposite said mounting plate completely sealing said channel bottom opening, and

a plurality of guide rod mounting holes extending between said mounting plate guide rod hole and said concrete body portion top surface.

2. The tower foundation of claim 1 wherein said main body portion of said guide rod mounting nut is welded to said mounting plate of said guide rod mounting nut.

3. A tower foundation comprising:

a concrete base slab having a plurality of guide rod mounting holes extending from a top surface to a plurality of guide rod mounting nuts, each nut having a mounting plate coupled to a main body portion with a threaded channel therethrough and a sealing plate sealing a bottom opening of said threaded channel,

at least one pillar slab having a plurality of guide rod mounting holes aligned with said base slab guide rod mounting holes,

a concrete crown slab having a plurality of guide rod mounting holes aligned with said at least one pillar slab plurality of guide rod mounting holes;

a plurality of guide rods, each said guide rod extending through one said base slab guide rod mounting hole, one said pillar slab guide rod mounting hole, one said crown slab guide rod mounting hole, and threaded into one said threaded channel of said guide rod mounting nut main body portion.

4. The tower foundation of claim 3 wherein said main body portion of said guide rod mounting nut is welded to said mounting plate of said guide rod mounting nut.

5. A tower foundation base slab comprising,

a concrete body portion having a top surface, a bottom surface opposite said top surface;

a plurality of guide rod mounting nuts embedded within said concrete body portion, each guide rod mounting nut having a plate with a guide rod hole therethrough, a main body portion permanently mounted to said plate, said main body portion including a threaded channel therethrough, and a sealing plate coupled to said main body portion and sealing one end of said channel, and

a plurality of guide rod mounting holes extending from said concrete body portion top surface to said main body portion threaded channel.

6. The tower foundation of claim 5 wherein said main body portion of said guide rod mounting nut is welded to said plate of said guide rod mounting nut.

7. The tower foundation of claim 5 wherein said guide rod mounting nut plate is positioned directly above said guide rod mounting nut main body portion.

8. The tower foundation of claim 7 wherein said plate guide rod hole is axially aligned with said threaded channel.