Note: Descriptions are shown in the official language in which they were submitted.
Pile Cap Auger
Field of the Invention
This invention pertains generally to the installation of drilled concrete
piles. More specifically
the invention is a unique attachment for a rotary pile rig (RPR) that
increases the diameter of the
top portion of a vertically drilled pile to accept subsequent structural
elements such as beams or
columns; commonly referred to as a pile cap. The auger includes helical
flights that match the
pile cap dimension, reducing in diameter at a steep angle, terminating at or
below the bored pile
diameter. The auger is further provided with a centralizer to prevent offline
oscillation of the
auger during drilling operations.
The invention possesses numerous benefits and advantages over current
practices. In particular,
the invention utilizes an overbore principle to create an expanded opening
deeper than frost level
eliminating multiple steps in the traditional foundation construction process,
thereby affording
user cost and time reductions.
Moreover, the centralizer is interchangeable and, therefore, allows for the
same auger to be used
on a variety of pile diameters. The centralizer is further provided with
openings that direct excess
trimming down the pre-bored pile shaft, reducing binding and buildup. Because
of its flexibility
across multiple pile shaft diameters, the auger realizes optimized tooling
costs.
The auger is further provided with an extended drill stem and drill point.
This allows the tool to
be stored in the upright position by inserting the stem into the ground by the
RPR. This allows
for quick changes between attachments and minimum crew disruption.
A practical example of the flexibility possessed by the invention resides in
its ability to eliminate
steps from the sequence of construction. The practice of installing
foundations with pile caps is
split into multiple steps. A rotary pile rig (RPR) drills piles of a
prescribed diameter and length
into the ground. The hole is reinforced with steel rebar and filled to near
the surface with
concrete. Subsequently, a different team excavates below the completed pile.
Next a third team
installs void form, concrete formwork, pours the pile cap, and removes the
formwork. Finally,
the second team returns to backfill the completed foundation pile cap.
The configuration of the Pile Cap Auger eliminates these steps through
drilling below the frost
depth, eliminating debris build up with a steep shoulder cut, while using the
pile shaft as a
vertical guide to maintain verticality specifications.
Description Of Prior Art
It is known in the prior act to provide an auger for a RPR that provides a
single diameter pile
shaft from top to bottom. U.S. Patent Number 431,455A, which issued to W.
Bagleston on July
1, 1890, discloses an earth auger with means to reduce friction on the cutting
element. The auger
is the earliest known example of a single diameter auger.
Date Recue/Date Received 2022-01-13
Similarly, U.S. Patent Number 2221680A to Parrish, Jay, dated November 12,
1940, establishes
an earth boring auger with cutting flights along its length to improve the
accuracy of the shaft
location and clean cut holes of maximum diameter for an auger of given outside
diameter.
U.S. Patent Number 3311179A to John A Meredith, dated March 28, 1964,
introduces the notion
of a reamer to increase the size of a drilled caisson. Adapted for the
purposes of drilling holes in
earth structures of sufficient diameter and depth to receive intercontinental
ballistic missile
launch facilities. Meredith's invention pertains to very large openings and
high-torque operations
that take extended periods of time to complete. This invention addresses small
diameter openings
and quick production movements where multiple openings are completed each day.
U.S. Patent Number 9376880B2 issued to Andreas Stimpfle-Ziegler and assigned
to Bauer
Maschinen GmbH, introduces a progressive flight pattern in a double helix for
the purposes of
drilling into hard rock and capturing the cuttings above the auger in a
container. This device is
not intended to increase the size of a pilot pile or for the purposes of pile
caps. Rather, its
purpose is to create a bore hole in the ground in a single operation.
Canadian Patent Number 2620166X issued to Boyles Bros. Drilling (Eastern)
Ltd., Port Arthur,
Ontario, Canada introduces an underreamer. The purpose of the underreamer is
to expand the
pilot shaft diameter at the founding elevation of the pile into a bell shape.
The underreamer
cannot function at the top of the pile or to produce a pile cap.
United States Patent Number 1488525A issued to Lewis C Bayles, April 1, 1924,
introduces a
centralizer for the purposes of horizontal rock drilling, common in
underground mining. The
centralizer rests on the bottom of the horizontally drilled hole and allows
the drill bit to maintain
its horizontal alignment. The centralizer binds against the outer diameter of
the pre-bored hole.
Finally, United States Patent Number 10030501B2 issued to Aaron W. Logan,
Justin C. Logan,
And Patrick R. Derkacz, July 24, 2018, introduces a centralizer for deep
hydrocarbon drilling
operations. The drill stem passes through the centralizer, supporting a down-
hole probe, and is
then abandoned in the drilled hole when operations are complete. This
inventions centralizer is
fixed to the drill stem, is recovered after each use, and is interchangeable
to match the bored
diameter of the pile shaft.
It is apparent from the foregoing that the prior art fails to address
expanding the top of a drilled
pile to incorporate a pile cap of a larger diameter within the same operation.
Summary Of the Invention
The invention pertains to a quick-change auger which is provided with a drill
stem, helical flights
that concentrically reduce in diameter from a large atop to a smaller diameter
at the flight
termination point. Founded at the termination of the helical flights is an
interchangeable
centralizer with internal channels to shed trimmings and reduce binding. Below
the centralizer is
the remainder of the drill stem terminating into a drill tip allowing the tool
to be stored in the
upright position.
The auger is flexible across different brands and sizes of RPR. The kelly box
at the top of the
drill stem can be adapted to various kelly bar drive sizes.
Date Recue/Date Received 2022-01-13
The steel helical fighting is connected to the drill stem through welded
fabrication allowing for
flexibility of application. Flights are matched to the diameter of the pile
cap, the required pitch of
the side slope, the pilot hole diameter, and the material being drilled to
meet a range of
engineering requirements in different geographies.
The centralizer is a round steel section with internal bracing and a port for
mechanically
connecting to the drill stem. The centralizer matches the pre-bored hole
diameter to ensure the
drilling of the pile cap portion of the foundation is vertically aligned with
the pile shaft. The
centralizers internal bracing is configured to allow excess trimming to fall
through channels into
the depth of the pre-bored hole reducing binding potential. The configuration
of the centralizer
allows for a pin to be removed and itself replaced with a centralizer of a
different diameter.
Brief Description Of The Drawings
= FIG. 1 is a front plan view of the Pile Cap Auger invention
The Embodiments Of The Invention
In Which An Exclusive Property Or Privilege Is Claimed Are Defined As
Follows:
1. A rotary pile rig auger attachment with an elongated stem having a tapered
helical flight
pattern, said flights begin at the top of the auger below the kelly box
attachment point and
match the pile cap diameter prescribed by the engineer, said flights terminate
at a
diameter equal to or less than the pre-bore pile diameter, said flights are
guided by an
interchangeable centralizer, said centralizer is defined by a round steel
section with
internal bracing and a inner tube to receive the drill stem, said centralizer
has internal
channels to shed trimmings and a horizontal port such that a mechanical
connection to
join the centralizer to the stem/auger assembly allows for manual removal, the
drill stem
extending below the centralizer terminating into a drill tip so the rotary
pile rig can drill it
into the ground to store it safely in the upright position while not in use.
2. The pile cap auger recited in claim 1 is fabricated from steel materials
3. The pile cap auger recited in claim 1 wherein said drill stem utilizes a
kelly box
attachment at the top to accommodate various RPR manufacturers and kelly bar
sizes
4. The pile cap auger recited in claim 1 wherein said helical flights are
attached to the drill
stem by welded fabrication
5. The pile cap auger helical flights recited in claim 4 wherein said helical
flights match the
desired pile cap at their largest diameter at the top
6. The pile cap auger helical flights recited in claim 4 wherein said helical
flights taper in
diameter at a sufficient angle to create a finished should in the excavated
hole that will
shed dirt and debris to form an acceptable surface for concreting
7. The pile cap auger flights recited in claim 4 wherein said helical flights
terminate at a
dimension matching or less than the prescribed pile shaft diameter
Date Recue/Date Received 2022-01-13
