U.S. patent application number 10/581559 was filed with the patent office on 2007-05-17 for method and apparatus for installing a helical pile.
Invention is credited to Joseph R.E. Nimens.
Application Number | 20070110521 10/581559 |
Document ID | / |
Family ID | 34596896 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070110521 |
Kind Code |
A1 |
Nimens; Joseph R.E. |
May 17, 2007 |
Method and apparatus for installing a helical pile
Abstract
An apparatus and a method to assist in the installation of a
helical pile. The apparatus comprises a drive mechanism having an
engaged and a disengaged configuration. When in its engaged
configuration the drive mechanism operatively grips the exterior
surface of the helical pile. When in its disengaged configuration
the drive mechanism operatively releases the exterior surface of
the helical pile. Movement of the drive mechanism when in its
engaged configuration causes rotational movement of the pile. When
in its disengaged configuration the drive mechanism moves without
rotation of the pile.
Inventors: |
Nimens; Joseph R.E.;
(Ontario, CA) |
Correspondence
Address: |
MEREK, BLACKMON & VOORHEES, LLC
673 S. WASHINGTON ST.
ALEXANDRIA
VA
22314
US
|
Family ID: |
34596896 |
Appl. No.: |
10/581559 |
Filed: |
December 1, 2004 |
PCT Filed: |
December 1, 2004 |
PCT NO: |
PCT/CA04/02064 |
371 Date: |
June 2, 2006 |
Current U.S.
Class: |
405/232 |
Current CPC
Class: |
E02D 27/42 20130101;
E02D 7/22 20130101 |
Class at
Publication: |
405/232 |
International
Class: |
E02D 13/00 20060101
E02D013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 4, 2003 |
CA |
2,452,448 |
Claims
1. An apparatus to assist in the installation of a helical pile,
the apparatus comprising a drive mechanism operatively connected to
a power source, said power source causing said drive mechanism to
move in a first direction and then subsequently in a second
direction in a reciprocating fashion, said drive mechanism having
an engaged and a disengaged configuration, when in said engaged
configuration said drive mechanism operatively gripping the
exterior surface of said helical pile, when in said disengaged
configuration said drive mechanism operatively releasing the
exterior surface of said helical pile, movement of said drive
mechanism in said first direction placing said drive mechanism in
said engaged configuration and causing rotational movement of said
helical pile, movement of said drive mechanism in said second
direction placing said drive mechanism in said disengaged
configuration without rotation of said helical pile.
2. The device as claimed in claim 1 including at least one pile
guide, said pile guide engaging the exterior surface of said
helical pile to assist in maintaining said pile at a desired
inclination.
3. The device as claimed in claim 1 including a vertical loading
head having an engaged position, when in said engaged position said
vertical loading head releasably secured about the exterior surface
of said helical pile and permitting the application of a
longitudinally oriented force to said pile while permitting
rotational movement of said pile through operation of said drive
mechanism.
4. The device as claimed in claim 3 wherein said vertical loading
head has a disengaged position, when in said disengaged position
said vertical loading head free from contact with the exterior
surface of said helical pile.
5. The device as claimed in claim 1 wherein said drive mechanism
includes a drive chain received about the exterior surface of said
helical pile, said drive chain having a first end and a second end,
said first end of said drive chain secured to a reciprocating drive
member, said second end of said drive chain secured to a tensioning
device.
6. The device as claimed in claim 5 wherein said reciprocating
drive member is a hydraulic cylinder, a pneumatic cylinder, or an
electric solenoid.
7. The device as claimed in claim 6 wherein said tensioning device
comprises a spring, a pneumatic cylinder, a hydraulic cylinder or
an electric solenoid.
8. The device as claimed in claim 1 including an auger, said auger
operatively connected to a rotary drive mechanism such that upon
rotation and insertion of said auger into said helical pile said
auger extracts at least a portion of any soil and other debris
situated within said helical pile.
9. The device as claimed in claim 1 wherein said drive mechanism
includes a pair of jaw members, movement of said drive mechanism in
said first direction causing said jaw members to grip the exterior
surface of said helical pile and causing rotational movement of
said pile, movement of said drive mechanism in said second
direction disengaging said jaw members from the exterior surface of
said helical pile without rotation of said pile.
10. The device as claimed in claim 1 including two drive
mechanisms, said power source causing said drive mechanisms to move
in an opposed reciprocating fashion to permit continuous rotation
of said helical pile.
11. A method of installing a helical pile, the method comprising
the steps of: (i) operatively connecting a drive mechanism having
an engaged and a disengaged configuration to a power source, when
in said engaged configuration said drive mechanism capable of
gripping the exterior surface of the helical pile, when in said
disengaged configuration the drive mechanism releasing the exterior
surface of the helical pile; (ii) with said power source operating
said drive mechanism to move said drive mechanism in a first
direction that places said drive mechanism in said engaged
configuration such that further movement of said drive mechanism in
said first direction causes rotational movement of said pile; and,
(iii) thereafter, causing said power source to move said drive
mechanism in a second direction thereby placing said drive
mechanism in said disengaged configuration without rotation of said
helical pile.
12. The method as claimed in claim 11 including the further steps
of repeatedly operating said drive mechanism to move firstly in
said first direction and secondly in said second direction to cause
repeated reciprocal movement of said drive mechanism.
13. The method as claimed in claim 11 including the further step of
applying a force generally parallel to the longitudinal axis of
said pile while permitting rotational movement of said pile through
the operation of said drive mechanism.
14. The method as claimed in claim 11 including the step of
maintaining said pile at a desired inclination through the use of
one or more pile guides engaging the exterior surface of said
pile.
15. The method as claimed in claim 11 including the further step of
inserting a rotating auger into said helical pile to extract at
least a portion of any soil or debris situated therein.
16. An apparatus to assist in the installation of a helical pile,
the apparatus comprising a drive mechanism having an engaged and a
disengaged configuration, when in said engaged configuration said
drive mechanism operatively gripping the exterior surface of said
helical pile, when in said disengaged configuration said drive
mechanism operatively releasing the exterior surface of said
helical pile, wherein movement of said drive mechanism when in said
engaged configuration causes rotational movement of said pile, when
in said disengaged configuration said drive mechanism moving
without rotation of said pile.
17. The device as claimed in claim 16 including at least one pile
guide, said pile guide engaging the exterior surface of said
helical pile to assist in maintaining said pile at a desired
inclination.
18. The device as claimed in claim 16 wherein said drive mechanism
includes a drive chain received about the exterior surface of said
helical pile, said drive chain having a first end and a second end,
said first end of said drive chain secured to a reciprocating drive
member, said second end of said drive chain secured to a tensioning
device.
19. The device as claimed in claim 18 wherein said reciprocating
drive member causes a reciprocal movement of said drive chain and
stepped rotational movement of said helical pile.
20. A method of installing a helical pile, the helical pile being
of the type having a generally hollow longitudinally orientated
bore extending therethrough, the method comprising the steps of:
(i) with a drive mechanism imparting rotational movement to the
pile to cause the pile to be rotated into the ground; and, (ii)
extracting at least a portion of any accumulated soil or debris
from within the pile's hollow bore.
21. The method as claimed in claim 20 wherein said step of
extracting at least a portion of any accumulated soil or debris
from within the pile's hollow bore is carried out while the pile is
being rotated into the ground.
22. The method as claimed in claim 20 wherein said pile is
partially rotated into the ground prior to the extraction of soil
or debris from within the pile's hollow bore.
23. The method as claimed in claim 20 wherein said step of
extracting at least a portion of any accumulated soil or debris
from within the pile's hollow bore is carried out through inserting
a rotating auger into said bore.
24. The method as claimed in claim 20 wherein said step of
extracting at least a portion of any accumulated soil or debris
from within the pile's hollow bore is carried out through inserting
a vacuum tube into said bore.
25. An apparatus to assist in the installation of a helical pile of
the type having a generally hollow longitudinally orientated bore
extending therethrough, the apparatus comprising a drive mechanism
and a soil extractor, said drive mechanism imparting rotational
movement to the pile to cause the pile to be rotated into the
ground, said soil extractor operable to extract at least a portion
of any accumulated soil or debris from within the pile's hollow
bore.
26. The apparatus as claimed in claim 25 wherein said soil
extractor is an auger operatively connected to a rotary drive
mechanism.
27. The apparatus as claimed in claim 25 wherein said soil
extractor is a vacuum tube insertable into said hollow bore of said
pile.
28. The apparatus as claimed in claim 27 including a water jet
insertable into said hollow bore of said pile with said vacuum
tube.
29. An apparatus to assist in the installation of a helical pile,
the apparatus comprising a drive mechanism operatively connected to
a power source, said power source causing said drive mechanism to
move in a first direction and then subsequently in a second
direction in a reciprocating fashion, said drive mechanism
operatively connected to the exterior surface of said helical pile
such that reciprocal movement of said drive mechanism causes
rotational movement of said helical pile without appreciable
movement or displacement of said drive mechanism in a direction
generally parallel to the longitudinal axis of said pile.
30. The device as claimed in claim 29 wherein said drive mechanism
includes at least 2 actuating cylinders, said cylinders having
reciprocating pistons connected to a drive gear such that
alternating reciprocating movement of said pistons causes
continuous rotation of said drive gear.
31. The device as claimed in claim 30 having a drive chain
operatively engaging the exterior surface of said helical pile,
said drive chain further engaging said drive gear such that
rotation of said drive gear causes said drive chain to rotate said
helical pile.
32. An apparatus to assist in the installation of a helical pile,
the apparatus comprising a drive mechanism operatively connected to
a power source and to the exterior surface of said helical pile,
said power source causing said drive mechanism to impart rotational
movement to said helical pile without appreciable movement or
displacement of said drive mechanism in a direction generally
parallel to the longitudinal axis of said pile.
33. The device as claimed in claim 32 wherein said drive mechanism
continuously rotates said helical pile.
34. The device as claimed in claim 32 wherein said drive mechanism
includes a reciprocating drive that causes staggered rotational
movement of said pile.
35. The device as claimed in claim 32 wherein said drive mechanism
includes a drive chain received about the exterior surface of said
pile, movement of said drive chain imparting rotational movement to
said pile.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method and an apparatus that may
be used to install a helical or screw pile.
BACKGROUND OF THE INVENTION
[0002] Helical or screw piles have been used for decades to help
support the foundation of buildings, bridges and other civil
engineering structures. Traditionally helical piles were used
primarily in areas of weak or wet soil and their application was
somewhat limited as their installation was difficult without
mechanical assistance. However, more recently helical piles have
become considerably more widespread in use due to the advent of
high torque motors that are used to rotate the piles and drive them
into the ground. The resistence of a helical pile to both upward
and carrying loads makes it attractive for use in a wide range of
different situations. Today helical or screw piles are commonly
used in foundation support for commercial and residential
buildings, to help support temporary structures, as a support for
street light standards, for the support of oil and gas drilling and
pumping equipment, for bank retention, and for a wide variety of
anchoring applications.
[0003] Typically a helical pile is installed through the use of a
boom truck having a high torque motor positioned on the end of a
boom that may be connected to the upper end of the pile in order to
rotate the pile and drive it into the ground. Torque is transferred
from the motor to the pile through the use an intermediary coupling
that is either physically welded to the end of the pile or fastened
thereto through the use of bolts, pins or some other mechanical
fastener. While such a structure is effective in transmitting
rotational movement from the motor to the pile, it can also require
a considerable amount of labour to put into operation on account of
the need to weld, bolt, pin or otherwise secure the torque coupling
to the end of the pile.
[0004] In many instances piles of significant length are required,
which either necessitates the use of a large boom truck having an
extended reach or requires that a number of lengths of shorter
piling be welded or fastened together as they are driven into the
ground. Where a large boom truck is used to drive a lengthy helical
pile, difficulties can arise when trying to maintain the pile in a
vertical orientation due to the length of the pile and the weight
of the drive motor that is attached to its upper end.
[0005] The cost of utilizing a trunk having an extruded boom can be
significant. Large boom trucks also restrict the ability to work in
confined areas. In cases where a pile is to be installed in
sections, existing equipment makes it necessary to physically
attach (and then later remove) the intermediary drive member, to
each length of pile. Attaching, removing and subsequently
re-attaching the drive member is both time consuming and
costly.
[0006] There is therefore a need for an improved apparatus for
installing a helical or screw pile, particularly where the pile is
of significant length.
SUMMARY OF THE INVENTION
[0007] The invention therefore provides a method and an apparatus
that may be used to install a helical or screw pile whereby the
need for the use of a large boom truck is eliminated or minimized,
as is the requirement for physically welding, bolting or pinning an
intermediary drive member or torque coupling to the end of the pile
in order to connect the pile to the motor of a drive head. The
invention provides for a drive mechanism that imparts rotational
movement to a pile without appreciable movement or displacement of
the drive mechanism in a direction generally parallel to the
longitudinal axis of the pile.
[0008] Accordingly, in one of its aspects the invention provides an
apparatus to assist in the installation of a helical pile, the
apparatus comprising a drive mechanism operatively connected to a
power source, said power source causing said drive mechanism to
move in a first direction and then subsequently in a second
direction in a reciprocating fashion, said drive mechanism having
an engaged and a disengaged configuration, when in said engaged
configuration said drive mechanism operatively gripping the
exterior surface of said helical pile, when in said disengaged
configuration said drive mechanism operatively releasing the
exterior surface of said helical pile, movement of said drive
mechanism in said first direction placing said drive mechanism in
said engaged configuration and causing rotational movement of said
helical pile, movement of said drive mechanism in said second
direction placing said drive mechanism in said disengaged
configuration without rotation of said helical pile.
[0009] In a further aspect the invention provides a method of
installing a helical pile, the method comprising the steps of
operatively connecting a drive mechanism having an engaged and a
disengaged configuration to a power source, when in said engaged
configuration said drive mechanism capable of gripping the exterior
surface of the helical pile, when in said disengaged configuration
the drive mechanism releasing the exterior surface of the helical
pile; with said power source operating said drive mechanism to move
said drive mechanism in a first direction that places said drive
mechanism in said engaged configuration such that further movement
of said drive mechanism in said first direction causes rotational
movement of said pile; and, thereafter, causing said power source
to move said drive mechanism in a second direction thereby placing
said drive mechanism in said disengaged configuration without
rotation of said helical pile.
[0010] The invention also provides an apparatus to assist in the
installation of a helical pile, the apparatus comprising a drive
mechanism having an engaged and a disengaged configuration, when in
said engaged configuration said drive mechanism operatively
gripping the exterior surface of said helical pile, when in said
disengaged configuration said drive mechanism operatively releasing
the exterior surface of said helical pile, wherein movement of said
drive mechanism when in said engaged configuration causes
rotational movement of said pile, when in said disengaged
configuration said drive mechanism moving without rotation of said
pile.
[0011] In another aspect the invention concerns a method of
installing a helical pile, the helical pile being of the type
having a generally hollow longitudinally orientated bore extending
therethrough, the method comprising the steps of (i) with a drive
mechanism imparting rotational movement to the pile to cause the
pile to be rotated into the ground; and, (ii) extracting at least a
portion of any accumulated soil or debris from within the pile's
hollow bore.
[0012] The invention also provides an apparatus to assist in the
installation of a helical pile of the type having a generally
hollow longitudinally orientated bore extending therethrough, the
apparatus comprising a drive mechanism and a soil extractor, said
drive mechanism imparting rotational movement to the pile to cause
the pile to be rotated into the ground, said soil extractor
operable to extract at least a portion of any accumulated soil or
debris from within the pile's hollow bore.
[0013] In a further alternate embodiment the invention provides an
apparatus to assist in the installation of a helical pile, the
apparatus comprising a drive mechanism operatively connected to a
power source, said power source causing said drive mechanism to
move in a first direction and then subsequently in a second
direction in a reciprocating fashion, said drive mechanism
operatively connected to the exterior surface of said helical pile
such that reciprocal movement of said drive mechanism causes
rotational movement of said helical pile without appreciable
movement or displacement of said drive mechanism in a direction
generally parallel to the longitudinal axis of said pile.
[0014] In yet as further aspect the invention concerns an apparatus
to assist in the installation of a helical pile, the apparatus
comprising a drive mechanism operatively connected to a power
source and to the exterior surface of said helical pile, said power
source causing said drive mechanism to impart rotational movement
to said helical pile without appreciable movement or displacement
of said drive mechanism in a direction generally parallel to the
longitudinal axis of said pile.
[0015] Further aspects and advantages of the invention will become
apparent from the following description taken together with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For a better understanding of the present invention, and to
show more clearly how it may be carried into effect, reference will
now be made, by way of example, to the accompanying drawings which
show the preferred embodiments of the present invention in
which:
[0017] FIG. 1 is a side view of a street light standard as it would
typically be supported upon a helical pile;
[0018] FIG. 2 is a side view of an apparatus constructed in
accordance with a preferred embodiment of the present
invention;
[0019] FIG. 3 is a front view of the apparatus shown in FIG. 2;
[0020] FIG. 4 is a plan view along the line 4-4 in FIG. 1 showing a
pile guide in accordance with one embodiment of the present
invention;
[0021] FIG. 5 is a plan view along the line 5-5 in FIG. 1 showing a
pile drive mechanism in accordance with one embodiment of the
present invention;
[0022] FIG. 6 is a plan view along the line 6-6 in FIG. 1 showing a
vertical loading head, in accordance with a preferred embodiment of
the present invention;
[0023] FIG. 7 is a plan view of the vertical loading head shown in
FIG. 6 in an open position;
[0024] FIG. 8 is a side view of the vertical loading head shown in
FIG. 6;
[0025] FIG. 9 is a partial exploded plan view of the vertical
loading head shown in FIG. 6;
[0026] FIG. 10 is a sectional view taken along the line 10-10 in
FIG. 6;
[0027] FIG. 11 is a partial side view of an alternate embodiment of
the pile drive mechanism shown in FIG. 2;
[0028] FIG. 12 is a partial plan view of a third embodiment of the
pile drive mechanism shown in FIG. 2;
[0029] FIG. 13 is a partial plan view of a fourth embodiment of the
pile drive mechanism shown in FIG. 2;
[0030] FIG. 14 is a partial plan view of a fifth embodiment of the
pile drive mechanism shown in FIG. 2;
[0031] FIG. 15 is a side view of an alternate embodiment of the
apparatus shown in FIG. 2;
[0032] FIG. 16 is a partial plan view of an alternate drive
mechanism pursuant to one embodiment of the invention; and,
[0033] FIG. 17 is a sectional view taken along the line 17-17 in
FIG. 16.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0034] The present invention may be embodied in a number of
different forms. However, the specification and drawings that
follow describe and disclose only some of the specific forms of the
invention and are not intended to limit the scope of the invention
as defined in the claims that follow herein.
[0035] By way of introduction, FIG. 1 shows a typical street light
standard 1 that is anchored to the ground through the use of a
helical or screw pile 2. Most commonly helical pile 2 will be
comprised of an elongate, generally hollow, cylindrical body or
pipe having at its lower end a helical thread attached thereto such
that rotation of the pipe causes the pile to be screwed or augered
into the ground.
[0036] FIGS. 2 and 3 show a preferred embodiment of the present
invention as it would typically be connected to a boom truck or
vehicle 3. From a thorough understanding of the invention it will
be understood that the apparatus constructed in accordance with the
invention described herein may in some instances be attached to a
boom truck or other vehicle while other cases it may be
self-contained on its own platform or skid, particularly where its
use is required in confined areas. For illustration purposes an
embodiment of the invention mounted upon a boom truck 3 (as shown
in FIGS. 2 and 3) will be described in detail below.
[0037] According to the invention there is provided an apparatus 4
to assist in the installation of a helical or screw pile 2.
Apparatus 4 is comprised generally of a drive mechanism 5 that is
operatively connected to a power source 6. It is expected that in
most instances power source 6 will be comprised of a hydraulic pump
capable of providing pressurized hydraulic fluid to the various
components of apparatus 4 where required. Alternately, power source
6 could be pneumatic or electrical in nature. In any event, power
source 6 is operatively connected to drive mechanism 5 in order to
allow for movement of the drive mechanism in a first direction, and
then subsequently in a second direction, in a generally
reciprocating fashion. In the embodiment of the invention shown in
FIGS. 2 and 3, the reciprocating movement of drive mechanism 5 is
accomplished through the use of a hydraulic or pneumatic cylinder
7. However, as discussed above, movement may also be achieved
through the use of an electric solenoid or through the utilization
of a mechanical linkage having a rotary gear or cam drive (not
shown) allowing for reciprocal movement of the drive mechanism.
[0038] As is shown particularly in FIGS. 2 and 5, in one embodiment
of the invention drive mechanism 5 includes a drive chain 8 that is
received about the exterior surface of helical pile 2. In order for
the apparatus to function as intended drive chain 8 must completely
encircle the exterior surface of the helical pile. In FIGS. 2 and 5
chain 8 is shown wrapped around the pile one and one-half times.
Drive chain 8 has a first end 9 secured to the reciprocating drive
member, which in the case of FIGS. 2 and 5 is hydraulic cylinder 7.
The second end 10 of drive chain 8 is secured to a tensioning
device 11 that may be a spring (as in FIGS. 2 and 5) or,
alternatively, any one of a wide variety of other tensioning
devices which could include hydraulic or pneumatic cylinders or
electric solenoids. The opposite ends of hydraulic cylinder 7 and
tension device 11 that are not connected to drive chain 8 are
securely fastened to a portion of the frame 12 of apparatus 4 such
that retraction of the piston within cylinder 7 causes a tightening
of drive chain 8 about the exterior surface of helical pile 2. At
that point drive mechanism 5 is placed in an engaged configuration
with the drive chain securely gripping the exterior surface of pile
2. Once chain 8 is firmly gripped about the exterior surface of
pile 2, further retraction of the piston within cylinder 7 causes
movement of the chain in a first direction toward cylinder 7, and a
resulting rotational movement of the helical pile. Rotation of the
pile forces it to be driven or screwed into the ground. Depending
upon the nature of the auger on the end of the pile, chain 8 may be
wrapped in either a clockwise or counterclockwise manner around the
pile's surface, as required to drive the pile in a desired
direction. Movement of drive mechanism 5 in this manner may be
referred to as a power stroke.
[0039] Once hydraulic cylinder 7 has reached the end of its
movement in its first direction away from pile 2, the flow of
hydraulic fluid may be reversed to allow the piston to be drawn
outwardly from the cylinder toward the pile thereby relieving the
tension in drive chain 8. As the tension in the drive chain is
relieved, drive mechanism 5 will proceed to a disengaged
configuration where chain 8 is released from its gripping contact
with the exterior surface of helical pile 2. The chain will then be
pulled or slid in an opposite direction (ie with second end 10
moving away from the pile) through the operation of tensioning
device 11. With the extension of hydraulic cylinder 7 and the
movement of drive chain 8, the operation of tensioning device 11
causes the drive mechanism to return to a disengaged configuration
while the drive chain slides loosely around the exterior surface of
helical pile 2. This movement may be referred to as a return stroke
and occurs without rotating the pile.
[0040] It will be appreciated by those skilled in the art that the
reciprocal movement of drive mechanism 5 between the power and
return strokes described above will cause drive mechanism 5 to
repeatedly engage and disengage the exterior surface of the helical
pile, effectively causing the pile to be ratchetted into the ground
through the application of successive, spaced apart, power strokes.
Depending upon the hardness and characteristics of the ground
through which helical pile 2 is to be driven, the relative strength
of tensioning device 11 may have to be adjusted to prevent slippage
of chain 8 about the pile's surface. Where tensioning member 11 is
a spring, the spring may be replaced with a stronger string having
a greater spring constant. In addition, a spring tensioner 14 (see
FIG. 11) may be used to place the spring in a constant state of
tension. Alternatively, where tensioning device 11 is a hydraulic
or pneumatic cylinder or an electric solenoid, adjustments may be
made to increase the amount of tension that hydraulic cylinder 7
must apply to drive chain 8 before the chain is permitted to move.
The portions of the links of drive chain 8 that contact the
exterior surface of helical pile 2 may also be fitted with small
gripping teeth or coated with an abrasive substance to help enhance
the friction between the chain and pile 2 and to prevent slippage
during the power stroke. In still a further embodiment drive chain
8 may be wrapped around the exterior of the helical pile a number
of times to increase the surface to surface contact between the
drive chain and the pile.
[0041] The drive mechanism described above will permit helical pile
2 to be rotated and screwed into the ground without the need to
attach a large high torque motor to the upper end of the pile.
Drive mechanism 5 may also be mounted in close proximity to the
ground avoiding the need for large boom trucks when driving lengthy
piles. It will also be appreciated that drive mechanism 5 does not
require the welding or bolting of drive couplings onto the surface
of the helical pile, and does not present a hindrance to
maintaining the pile in a desired orientation. In one preferred
embodiment of the invention hydraulic cylinder 7 and tensioning
device 11 are rotatably attached to the frame 12 to allow both
devices to be displaced in a generally vertical plane so that they
may be tipped in a downward direction as the pile is screwed into
the ground during a power stroke. On the return stroke hydraulic
cylinder 7 and tensioning device 11 will tend to swing in an upward
direction until they are approximately horizontal once again.
Accordingly, the described structure allows helical pile 2 to move
in a vertical direction as it is rotated without interference from
drive mechanism 5.
[0042] It should also be noted that each successive power stroke
will entail the application of force to a different portion of the
exterior surface of helical pile 2 as the pile slowly moves
downward into the ground. Any tendency for the walls of the pile to
become damaged through contact with chain 8 is therefore minimized.
Further, depending upon the speed at which it is desired to turn
the pile a single drive mechanism 5 may be utilized (see FIG. 11)
or, alternatively, two drive mechanisms may be installed on
apparatus 4 as shown in FIG. 2. Where two such drive mechanisms are
utilized they are preferably synchronized with their power strokes
opposite to one another so that while one drive mechanism is
undergoing a power stroke the other drive mechanism is undergoing a
return stroke. In this manner pile 2 will effectively be
continuously rotated.
[0043] It should be appreciated by those skilled in the art that a
variety of other reciprocating drive mechanisms could be utilized
in place of the chain drive mechanism described above. Three such
alternate embodiments of the invention are shown in FIGS. 12, 13
and 14. In each of these Figures drive mechanism 5 includes a pair
of jaw members 15 that have an engaged configuration, where they
grip the exterior surface of helical pile 2, and a disengaged
configuration where they are released from the exterior surface of
the pile. As in the case of drive chain 8, when jaw members 15 grip
the exterior surface of the pile movement of cylinder 7 (i.e., the
power stroke) will cause the pile to rotate. Movement of the piston
in cylinder 7 in the opposite direction (ie the return stroke)
disengages the jaws from the exterior surface of pile 2 allowing
the jaws to be rotated back in an opposite direction without
rotating the pile.
[0044] In the embodiments shown in FIGS. 12 and 13, drive mechanism
5 preferably includes a tensioner 16 to engage jaw member 15 about
surface of pile 2. Tensioner 16 may be a spring, hydraulic or
pneumatic cylinder, or an electrical solenoid. In FIG. 12 tensioner
16 is shown as comprising a hydraulic cylinder that is used to
rotate jaw members 15 about a pin 17 to allow the jaws to either
engage or disengage pile 2. It will be noted that depending upon
sequencing of the operation of cylinders 7 and 16 the helical pile
may be caused to rotate in either a clockwise or counterclockwise
direction.
[0045] FIG. 13 is a variation of FIG. 12 wherein the pile is
generally square in cross-sectional shape, and wherein jaw members
15 effectively comprise a generally hook-like portion 18 with a
rotatable gate 19. In this embodiment tensioner 16 is preferably a
spring 20 that urges gate 19 toward the exterior surface of helical
pile 2. The power stroke occurs when the piston in cylinder 7 is
retracted, resulting in a clockwise rotational movement of the
pile. During the return stroke the piston is extended outwardly
from cylinder 7 and spring 20 will allow gate 19 to effectively
ride over the surface of the pile to permit hook-like portion 18 to
be rotated in a counterclockwise direction without a corresponding
rotation of helical pile 2.
[0046] The embodiment of the drive mechanism shown in FIG. 14
functions in a generally similar fashion to that shown in FIGS. 12
and 13, however, through the use of a significantly different
structure. In FIG. 14 jaw members 15 effectively comprise a first
jaw portion 21 and a second jaw portion 22. Second jaw portion 22
is connected at one end to first jaw portion 21 through a pin 23.
The opposite end of second jaw portion 22 is secured to a
connecting rod 24 by means of a pin 25. Connecting rod 24 is
attached to the piston of cylinder 7 and provides a means to impart
movement to jaw portions 21 and 22. The end of first jaw portion 21
adjacent to cylinder 7 contains a first leg 26 and a second leg 27.
First leg 26 is fixed to connecting member 24 by way of a bolt or
pin 28. Second leg 27 is loosely fixed to connecting rod 24 by
means of pin 29 that is attached to the connecting rod 24 but
received through an oversized bore 30 extending through second leg
27. Situated about the interior of first and second jaw portions 21
and 22 is a series of grippers 31 that are designed to engage and
firmly grasp the exterior surface of helical pile 2.
[0047] In operation, when the piston of cylinder 7 is retracted the
loose connection between pin 29 and bore 30 will effectively cause
first jaw portion 21 to rotate about pin 28 driving grippers 31
into the exterior surface of the helical pile until bore 30
prevents any further movement of the jaw members relative to
connecting rod 24. At that point further retraction of the piston
into cylinder 7 will effectively result in a rotational force being
applied to helical pile 2 through grippers 31. When the movement of
cylinder 7 is reversed, with the piston extracted from the
cylinder, first jaw portion 21 will rotate slightly in a
counterclockwise direction about pin 28 until further movement of
the jaw member relative to connecting rod 24 is halted by
engagement of pin 19 with the side of bore 30. However, the small
counterclockwise rotation is sufficient to disengage grippers 31
from the exterior surface of helical pile 2 such that further
withdrawal of the piston from cylinder 7 enables the jaw members to
be rotated in a counterclockwise direction about the exterior
surface of the pile without rotation of the pile itself. In this
manner the reciprocal movement of cylinder 7 will effectively be
transformed into a clockwise rotational movement of pile 2.
Reversing the relative positions of pins 28 and 29 so that pin 28
is a smaller pin received within a larger diameter bore, will
permit the embodiment of drive mechanism 5 shown in FIG. 14 to
effectively drive the pile in a counterclockwise direction.
[0048] Yet a further embodiment of drive mechanism 5 is shown in
FIGS. 16 and 17. In this embodiment drive mechanism 5 includes at
least two actuating cylinders 58 and 59 having reciprocating
pistons 60 and 61, respectively, that are connected to a drive gear
62. In the structure that is shown in the enclosed Figures the
attachment of pistons 60 and 61 to drive gear 62 is offset by 90
degrees such that alternating reciprocal movement of the pistons
will cause rotation of drive gear 62 about a centrally disposed
shaft 63. In a similar fashion to that as described above with
respect to the embodiment shown in FIG. 2, drive chain 8 is wrapped
around the exterior surface of helical pile 2 so that movement of
the drive chain is capable of imparting rotational movement to the
pile. In the case of the structure shown in FIGS. 16 and 17 the
ends of the drive chain are connected and the chain forms a
continuous loop that both encompasses the exterior surface of the
pile and engages drive gear 62. Accordingly, reciprocal and
alternating movement of pistons 60 and 61 will cause drive gear 62
to rotate in a continuous fashion, which in turn will impart a
continuous rotational movement to helical pile 2. In order to
maintain and/or adjust the tension of drive chain 8 it may be
desirable to include a tensioning device (not shown) which may take
the form of any one of a wide variety of devices commonly used to
maintain tension in a chain.
[0049] As the helical pile is continuously rotated the drive chain
will engage the exterior surface of the pile and be rotated in
unison therewith around the pile in a generally helical or
screw-like path. As portions of the chain come into contact with
the surface of the pile other portions will be released permitting
both the pile and the chain to be rotated, while at the same time
permitting vertical movement of the pile (in either an upward or
downward direction) without appreciable or significant movement or
displacement of the drive mechanism in a direction generally
parallel to the longitudinal axis of the pile. To help facilitate
the relative movement of the chain and the pile, particularly in
instances where the pile is rapidly advanced into or out of the
ground, drive gear 62 may be inclined relative to the axis of
helical pile 2. It should also be noted that while the embodiment
shown in FIGS. 16 and 17 includes the use of two actuating
cylinders, through mechanical modification of the drive structure
and the control mechanism operating the drive mechanism, one, two
or more cylinders could be utilized.
[0050] Referring again to FIGS. 2 and 4, in one preferred
embodiment of the invention apparatus 4 includes at least one pile
guide 32 that engages the exterior surface of helical pile 2 to
assist in maintaining the pile at a desired degree of inclination.
Pile guide 32 is received about the exterior surface of pile 2 and
includes a series of rollers 33 spaced apart about the exterior
surface of the pile to effectively confine the pile therebetween.
Preferably rollers 33 are positioned in a generally vertical
configuration such that they do not interfere with the rotational
movement of the pile in the event that they come into contact with
its exterior surface. In addition, pile guide 32 includes a gate
member 34 that may be opened or closed to allow for the pile guide
to be received about helical pile 2. In the embodiment shown in
FIG. 4, gate 34 is held in place through a pair of pins or bolts
35. Pile guide 32 is preferably secured to frame 12 of apparatus 4.
In cases where lengthy piles are to be driven, both an upper and a
lower pile guide may be utilized. In such instances (see FIGS. 2
and 3) the upper pile guide may be secured to a vertical column
portion 36 of frame 12.
[0051] Apparatus 4 may further include a soil extractor situated
above the end of pile 2. In FIGS. 2 and 3 the soil extractor is an
auger 37 that is operatively connected to a rotary drive member 38.
Rotary drive member 38 is preferably a hydraulic motor, but may
also be pneumatic or electrically operated. The rotary drive member
is slidably received upon vertical column 36 enabling it to be
moved in a vertical plane to allow for auger 37 to be inserted into
and retracted from helical pile 2. In the embodiment shown,
vertical movement of rotary drive member 8 is accomplished through
operation of a jack screw 39, however, it will be understood that
many other manners of moving rotary drive member 38 and auger 37 in
an upwardly or downwardly direction may be utilized. Such alternate
methods include the use of hydraulic cylinders, pneumatic
cylinders, electric solenoids, chain drives, and other similar
mechanisms.
[0052] Since helical piles are generally hollow structures with a
cylindrical bore extending through them, as they are rotated into
the ground their centre cavities tend to become filled or partially
filled with soil. Soil within the pile tends to increase the
resistance of the pile to rotational movement which has a
corresponding increase in the amount of torque required to rotate
the pile into or out of the ground. In addition, as soil builds up
within the interior of the pile the soil tends to plug the pile's
internal bore such that as the lower end of the pile is rotated
further into the ground the surrounding soil can no longer enter
the hollow interior of the pile and must be laterally displaced.
For small diameter piles in soft formations, displacing the soil at
the tip of the pile may not present much difficulty. However, for
large diameter piles and in hard soil formations laterally
displacing the soil at the tip of the pile can have a very
significant impact on the amount of torque required to drive the
pile into the ground. The presence of soil or other debris within
the internal bore through pile 2 also has little effect on the
weight bearing capacity of the pile. Accordingly, through inserting
auger 37 into the hollow interior of helical pile 2 at least a
portion of any soil or other debris situated within the pile can be
removed, effectively reducing the overall weight of the structure
and enhancing the ability of the pile to be driven into the ground
through providing a space into which additional soil may be
displaced as the pile is driven downwardly. The result is that less
energy and less torque is required to drive the pile into the
ground. In addition, extending the lower end of the auger down to
the bottom tip of the pile provides the ability to loosen the soil
as the pile is rotated, further reducing the amount of torque
required to set the pile.
[0053] An alternate embodiment of the invention where the soil
extractor is a vacuum tube 55 and a vacuum head 56 is shown in FIG.
15. In this embodiment, rather than augering soil from within the
interior of pile 2 a vacuum tube 55 may be used to remove soil and
other debris from the pile. To assist in loosening and extracting
the soil inside the pile the vacuum tube 55 may include a water jet
57. Water expelled through jet 57 not only loosens the soil within
the pile but may be used to fluidize the soil making it easier to
extract under suction. In addition to auger 37 and vacuum tube 55,
it should be understood that various other means of removing and or
loosening the soil within the hollow interior or helical pile 2 may
be utilized.
[0054] In accordance with another one of the preferred embodiments
of the invention, apparatus 4 further includes a vertical loading
head 40. As indicated in FIGS. 2 and 3, vertical loading head 40 is
mounted upon vertical column 36 of frame 12 and is moveable in an
axial direction along the length of column 36, generally parallel
to the longitudinal axis of helical pile 2. Where vertical column
36 is a standard I-beam vertical loading head 40 maybe secured
thereto through the use of a pair of plates 41 that form a channel
within which the flange portion 42 of column 36 maybe received (see
FIG. 6). In this manner the vertical loading head will be secured
to vertical column 36, but at the same time permitted to slide
axially along the length of the column. In the embodiment of the
invention shown in FIGS. 2 and 3, vertical positioning and movement
of loading head 40 is accomplished through the use of a cylinder 43
which may be hydraulic, pneumatic or electrically operated. It
will, of course, be appreciated that very wide variety of other
methods of attaching vertical loading head 40 to column 36 may be
used in conjunction with an equally wide variety of methods of
positioning and moving the vertical loading head along the length
of the column. Other methods of imparting vertical movement to
loading head 40 include the use of jack screws, drive belts, drive
chains, and various gear drive systems powered by electric,
hydraulic or pneumatic motors.
[0055] Referring to FIGS. 6 through 10, vertical head 40 includes
generally symmetrical jaws 44 and 45 which having pile engaging
members 46 and 47 that are releasably securable about the exterior
surface of helical pile 2. Jaws 44 and 45 are typically secured to
a frame 48 of loading head 40, which in turn is secured to vertical
column 36 through the use of plates 41 as described above. A piston
49, positioned between jaws 44 and 45, provides the means to open
and close the jaws about the exterior surface of the pile. Through
operation of piston 49 vertical loading head 40 is provided with an
engaged position with pile engaging members 46 and 47 releasably
secured about the exterior surface of helical pile 2 (see FIG. 6),
and a disengaged position with pile engaging members 46 and 47 free
from contract with the exterior surface of the pile (see FIG. 7).
When jaws 44 and 45 are in their disengaged position they are
preferably separated by distance large enough to allow for the pile
to be received between the jaws. The engagement of the jaw members
with the surface of the pile permits the application of a vertical
or longitudinal (relative to the axis of the pile) force to be
applied to the pile. The ability to apply such a longitudinally
oriented force can be of assistance in helping to urge the pile
downward where the pile is being installed in a clay or hard ground
formation. Alternately, a vertically upward directed force can be
of use when trying to extract a pile from the ground.
[0056] While vertical loading head 40 is applying a longitudinally
oriented force to the pile it must also permit the pile to freely
rotate. To this end, in the embodiment of the invention shown in
FIGS. 6 through 10 pile engaging members 46 and 47 are equipped an
internal semi-circular groove 50 into which are received a series
of bearing plates 51. Bearing plates 51 contain grippers 52 on
their interior surface that firmly grasp the exterior surface of
helical pile 2 when a clamping force is applied to the bearing
plates through movement of jaws 44 and 45 to their engaged
position. That is, as jaws 44 and 45 are moved toward the exterior
surface of helical pile 2, pile engaging members 46 and 47 will
drive bearing plates 51 inwardly toward the pile until grippers 52
firmly engage the pile's exterior surface. At that point a vertical
load (which may be in either the upward or downward direction)
applied to loading head 40 will be transmitted directly to the pile
through bearing plates 51 and grippers 52. At the same time, since
bearing plates 51 are received within grooves 50 in pile engaging
members 46 and 47, the pile will be free to rotate under the
influence of drive mechanism 5. Grease or various other lubricants
may be applied between bearing plate 51 and groove 50 to reduce the
frictional contact therebetween. It should also be noted that while
bearing plates 51 are shown as generally plate-like elements, a
variety of other bearing structures could equally be employed.
[0057] With a complete and thorough understanding of the preceding
description of apparatus 4, it will be understood that the
apparatus presents a means to rotate and to assist in the
installation of a helical pile through the use of a drive mechanism
that may be mounted close to the ground without the need for large
boom trucks or derricks. The apparatus also allows for the rotation
of the pile without the use of couplings or drive members that must
be welded, bolted or otherwise fixed to the pile. The described
apparatus provides a simple, efficient and cost effective manner of
rotating the pile and turning it into the ground. Through the use
of one or more pile guides 32, the vertical orientation of the pile
can be maintained at virtually any desired angle. The incorporation
of vertical loading head 40 into apparatus 4 provides an operator
with the ability to apply a vertical load to the pile (in either an
upward or downward direction) to assist in either installing or
extracting a pile. In situations where hard or wet ground
formations are encountered, auger 37 may be operated to extract a
portion of the dirt or other debris within the hollow interior of
the pile to further aid in its installation or removal.
[0058] As discussed, apparatus 4 may include one, two or more drive
mechanisms that may be operated in unison to increase the amount of
rotational force available to be applied to the pile. Alternatively
the drive mechanisms may be operated sequentially so that the
combined reciprocal movement of each individual drive member
results in a constant rotation of the pile. Furthermore, relatively
simple adjustments to drive mechanism 5 allows the drive mechanism
to rotate the pile in either a clockwise or counterclockwise
direction as may be necessary to install or extract a pile. Where
the drive mechanism is a chain drive, reversing the direction of
pile rotation is as simple as wrapping the chain around the pile in
the opposite direction. Where tensioning device 11 is a hydraulic
cylinder, a pneumatic cylinder, an electric solenoid or similar
device, reversing the direction of pile rotation can be achieved
through reversing the stroke on cylinder 7 and device 11. In the
case where the tensioning device is a hydraulic or pneumatic
cylinder reversing the operation of the cylinders could be
accomplished through the use of reversing values on the cylinder
supply and return lines.
[0059] The described structure also presents the ability to
construct a compact device that can easily fit on the back of a
truck or that could be independently mounted on a skid having a
dedicated power source. The embodiment shown in FIGS. 2 and 3
represents but one example of a vehicle that may be used for
purposes of transporting and operating apparatus 4. In this
instance the apparatus is attached to the end of a boom 53
containing a series of cylinders 54 that can be operated to adjust
the positioning of frame 12, and hence the vertical inclination of
helical pile 2.
[0060] It is to be understood that what has been described are the
preferred embodiments of the invention and that it may be possible
to make variations to these embodiments while staying within the
broad scope of the invention. Some of these variations have been
discussed while others will be readily apparent to those skilled in
the art.
* * * * *