U.S. patent application number 14/896570 was filed with the patent office on 2016-05-19 for improvements in & relating to pile and post driving equipment.
The applicant listed for this patent is PROGRESSIVE IP LIMITED. Invention is credited to Rodney Warwick SHARP.
Application Number | 20160138238 14/896570 |
Document ID | / |
Family ID | 52008413 |
Filed Date | 2016-05-19 |
United States Patent
Application |
20160138238 |
Kind Code |
A1 |
SHARP; Rodney Warwick |
May 19, 2016 |
IMPROVEMENTS IN & RELATING TO PILE AND POST DRIVING
EQUIPMENT
Abstract
The present invention is directed to an impact driver, which
relies on multiple connected piston and cylinder assemblies which
sequentially fire; a first auxiliary piston assembly charged to
compress a compressible fluid with a piston rapidly releases the
charge on said piston allowing the compressed fluid, which is
typically a gas, to accelerate said auxiliary piston. This
auxiliary piston is connected to a second travelling primaty piston
assembly which it accelerates. Within the primary piston assembly a
primary piston can be charged to compress a compressible fluid. The
charge on the primary piston can also be rapidly released to
accelerate the primary piston. The primary piston may be connected
to a striking element, or successive travelling piston and cylinder
assemblies which ultimately connect to a striking element.
Inventors: |
SHARP; Rodney Warwick;
(Hamilton, NZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PROGRESSIVE IP LIMITED |
Hamiliton |
|
NZ |
|
|
Family ID: |
52008413 |
Appl. No.: |
14/896570 |
Filed: |
June 9, 2014 |
PCT Filed: |
June 9, 2014 |
PCT NO: |
PCT/NZ2014/000110 |
371 Date: |
December 7, 2015 |
Current U.S.
Class: |
173/206 |
Current CPC
Class: |
E02D 7/02 20130101; E02D
7/10 20130101 |
International
Class: |
E02D 7/10 20060101
E02D007/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 7, 2013 |
NZ |
611704 |
Claims
1-15. (canceled)
16. Impact driving apparatus comprising an auxiliary piston
assembly comprising an auxiliary piston and cylinder, and in which
one side of the auxiliary piston can be charged to pressurise a
compressible fluid on the other side thereof; said auxiliary piston
being connected to a primary piston assembly in turn comprising at
least a primary piston and associated cylinder assembly; said
primary piston being able to be charged to pressurise a
compressible fluid on the other side thereof; and wherein said
primary piston assembly is able to slide within an outer housing;
said primary piston being connected to a striking element for
delivering energy to a target.
17. Impact driving apparatus as claimed in claim 16 in which
charging a piston comprises introducing hydraulic fluid into a
reservoir bounded at least partly by a said piston and its
associated cylinder.
18. Impact driving apparatus as claimed in claim 16 in which the
charge on a piston can be rapidly released.
19. Impact driving apparatus as claimed in claim 18, in which
hydraulic fluid can be released through a port having a relatively
large effective cross-sectional area.
20. Impact driving apparatus as claimed in claim 19 in which a said
port comprises a seated valve under bias towards a closed
position.
21. Impact driving apparatus as claimed in claim 16 in which the
charge on the auxiliary piston is released prior to the charge on
the primary piston.
22. Impact driving apparatus as claimed in claim 16 in which the
charge on the primary piston is released after its associated
cylinder assembly has acquired velocity due to the release of the
charge on the auxiliary piston.
23. Impact driving apparatus as claimed in claim 16 in which the
parameters for timing of charge release, extent of pressurisation
of compressible fluid, and component masses, are selected so that
recoil on the travelling primary piston assembly after release of
the charge on the primary piston causes said primary piston
assembly to any one of slow, stop, and change direction.
24. Impact driving apparatus as claimed in claim 17 which includes
means for slowing the striker element after it has travelled a
predetermined distance.
25. Impact driving apparatus as claimed in claim 24 which comprises
preventing further rapid release of hydraulic fluid acting on the
primary piston.
26. Impact driving apparatus as claimed in claim 16 in which the
compressible fluid is a gas.
27. Impact driving apparatus as claimed in claim 26 in which the
gas is nitrogen, or an inert gas mixture.
28. Impact driving apparatus as claimed in claim 16 in which the
striker element allows different heads to be attached or
substituted.
29. Impact driving apparatus as claimed in claim 16 including
mounting means for a vehicle.
Description
FIELD OF INVENTION
[0001] The present invention is directed to apparatus such as used
for driving posts and piles into the ground, and typically where
the post or pile is impacted. It can also be used for other impact
driving applications such as rock breaking, mining, etc.
BACKGROUND DESCRIPTION
[0002] The present invention is directed to impact and post
drivers, though it should be appreciated that they may find other
applications.
[0003] Typical impact type pile drivers use a falling weight to
impact the top of a post or pile. The degree of impact is dependent
upon the mass and velocity (typically the distance by which the
weight falls) of the impacting weight, and in simple terms this
roughly equates to F=1/2 mv.sup.2, though the mathematics, in
reality, is a little more complex. However it is enough to
illustrate that increasing the height which the weight falls
(increasing the velocity) has an exponential increase in the
resulting applied force, as opposed to the linear increase in force
resulting from increasing mass.
[0004] In practice, pile drivers are limited in both their height
and mass able to be lifted. The consequence is that as heavy a mass
as can be lifted (and supported) reasonably is used, but as high a
height (drop) as possible is used. Hence, most pile and post
drivers are large, bulky, and tall machines and often have to be
disassembled, or require special consideration, for transport. This
does limit their use, which commonly where the expense and
difficulty of getting the pile driver to the site is
justified--such as on large building projects.
[0005] The diesel hammer utilises a falling weight compressing air
and igniting injected diesel fuel to help drive an impact head
against the pile as well as driving the weight back up and drawing
in fresh air for a new cycle (falling/ignition/driving/lifting the
weight). Such devices are relatively efficient once running, but
are noisy and largely continuous. Also, unlike drop hammers, the
height of a drop and frequency of driving cannot be controlled
during the course of driving in diesel hammers. This can cause
problems in certain ground formations, such as where there is
underlying layers of minerals or bedrocks. It has been reported
that the use of a diesel hammer in such situations can cause damage
to the piles when it hits the more compacted layers. It was
necessary to vary the parameters of driving in order to address
this problem, which is beyond the scope of diesel hammers.
[0006] Also, the prior art devices are largely limited to driving
piles vertically. In some instances it is desirable to drive posts
or piles at an angle--such as a fence or strainer post on a
descending ridgeline or slope, where the posts are perpendicular to
the fence wires which are in turn parallel to the contour of the
hill. The prior art devices are not typically suitable for such
applications, even if able to be transported and stabilised in such
a situation.
[0007] In summary, it would be very useful to have pile and impact
driving equipment which allows driving parameters to be altered
readily. This can include driving frequency, and impact force.
[0008] It would also be very useful to have apparatus which is more
compact and transportable than the prior art and able to be used in
a wider range of applications, and mounted on a wider range of
vehicles--such as typical farm tractors, small utility trucks,
trailers, etc. It would be useful if such apparatus could be used
where it is often impractical to use large prior art
equipment--such as in remote or awkward areas, and tight spaces.
Examples can include everything from house piles to fence posts
(including in remote hilly areas), up to full size industrial and
construction applications.
[0009] Accordingly there is a need for improved apparatus able to
be more versatile, compact, and useable than typical large prior
art equipment such as falling weight and diesel hammer drivers.
[0010] Accordingly, it is an object of the present invention to
consider the above problems and propose an alternative.
[0011] At the very least it is an object of the present invention
to provide the public with a useful alternative choice.
[0012] Aspects of the present invention will be described by way of
example only and with reference to the ensuing description.
GENERAL DESCRIPTION OF THE INVENTION
[0013] According to one aspect of the present invention there is
provided impact driving equipment in which there is provided an
outer cylinder housing a primary internal cylinder assembly also
acting as a weight, and wherein this primary internal cylinder
includes an internal primary piston in turn connected to a striker
plate;
[0014] the primary internal cylinder assembly being connected to an
auxiliary piston within a further auxiliary piston and cylinder
assembly, and in which sliding of the auxiliary piston therein is
linked to movement of the primary internal cylinder assembly within
the outer cylinder;
[0015] and wherein there is a fluid reservoir area on one side of
the auxiliary piston in said auxiliary piston and cylinder assembly
which, when fluid is introduced, pushes said piston against gas
which begins to increase in pressure;
[0016] and wherein introducing fluid into said fluid reservoir area
also introduces fluid to within said primary internal cylinder
assembly, thereby pushing the primary internal piston against
pressurized gas therein;
[0017] and wherein the pressure of said introduced fluid can be
rapidly released to allow the pressurized gas to act against said
pistons and consequentially drive the striker plate in a striking
action.
[0018] According to a further aspect of the present invention there
is provided impact driving apparatus comprising an auxiliary piston
assembly comprising an auxiliary piston and cylinder, and in which
one side of the auxiliary piston can be charged to pressurise a
compressible fluid on the other side thereof;
[0019] said auxiliary piston being connected to a primary piston
assembly in turn comprising at least a primary piston and
associated cylinder assembly; said primary piston being able to be
charged to pressurise a compressible fluid on the other side
thereof; and wherein
[0020] said primary piston assembly is able to slide within an
outer housing;
[0021] said primary piston being connected to a striking element
for delivering energy to a target.
[0022] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which charging a piston comprises introducing hydraulic
fluid into a reservoir bounded at least partly by a said piston and
its associated cylinder.
[0023] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the charge on a piston can be rapidly released.
[0024] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which hydraulic fluid can be released through a port
having a relatively large effective cross-sectional area.
[0025] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which a said port comprises a seated valve under bias
towards a closed position.
[0026] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the charge on the auxiliary piston is released
prior to the charge on the primary piston.
[0027] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the charge on the primary piston is released after
its associated cylinder assembly has acquired velocity due to the
release of the charge on the auxiliary piston.
[0028] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the parameters for timing of charge release, extent
of pressurisation of compressible fluid, and component masses, are
selected so that recoil on the travelling primary piston assembly
after release of the charge on the primary piston causes said
primary piston assembly to any one of slow, stop, and change
direction.
[0029] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, which includes means for slowing the striker element after
it has travelled a predetermined distance.
[0030] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, which comprises preventing further rapid release of
hydraulic fluid acting on the primary piston.
[0031] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the compressible fluid is a gas.
[0032] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the gas is nitrogen, or an inert gas mixture.
[0033] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, in which the striker element allows different heads to be
attached or substituted.
[0034] According to another aspect of the present invention there
is provided impact driving apparatus, substantially as described
above, including mounting means for a vehicle.
[0035] There are a number of possible variations of embodiments of
the present invention, and which may have differing features
according to user need. These are envisaged as being within the
scope of the present invention.
[0036] To assist the reader it is probably best to explain the
principles of the invention in simple terms and to elaborate from
there. This will greatly simplify understanding the invention.
[0037] In simple terms one could state that the present invention
relies on two piston assemblies interconnected in series to drive a
striker plate, or the like, for impacting an object--such as a post
or spike to be driven into the ground, rock face, wall, etc., or
for other applications such as rock breaking, battering rams,
etc.
[0038] In the preferred embodiments of the present invention, the
serial arrangement of piston assemblies potentially allow for an
accumulation of kinetic energy which is delivered ultimately via
the striker plate. The potentially realisable advantages include
being able to build a much more compact unit, when compared with
the traditional prior art, for delivering a specific amount of
energy. This then makes the device easier to transport, and to
mount on smaller and more manoeuvrable vehicles.
[0039] Elaborating on the preferred embodiments, we have a
auxiliary piston arrangement, characterised by the fact that it is
able to be charged to pressurise a compressible fluid, typically a
gas. The method of charging the piston against the compressible
fluid is optional, but hydraulic arrangements are preferred in the
preferred embodiments.
[0040] Another characteristic is to be able to release the pressure
or force acting on the piston (to compress the compressible fluid)
relatively quickly so that the piston can be driven and accelerated
quite quickly by the compressed fluid.
[0041] Coupled to the piston is a primary piston assembly including
cylinder and piston. This primary piston assembly also acts as a
mass, being effectively a driven weight accelerated by the release
of the auxiliary piston.
[0042] The primary piston assembly is also characterised by its
piston, i.e. the primary piston in the apparatus, being able to be
charged to compress a compressible fluid, typically also a gas.
Also, the charge causing the compression of the compressible fluid
must also be able to be released relatively quickly. Again, the
preferred method of charging the piston is hydraulically.
[0043] In practice the charge acting on the primary piston is
released after the primary piston assembly has begun accelerating.
While the primary piston could be attached to a third piston
assembly (ad infinitum), in the preferred embodiment it is
connected to the striker plate.
[0044] The striker plate, prior to release of the charge acting on
the primary piston, already has kinetic energy by virtue of the
associated mass (the primary piston assembly) to which it is
connected, and the fact that this mass already has velocity due to
the firing of the auxiliary piston assembly.
[0045] Releasing the charge on the primary piston, then allows the
compressible fluid in the assembly to accelerate the primary piston
and striker plate. We therefore have the rapid release of more
`stored energy` which is converted to kinetic energy.
[0046] We have the sequential release of stored energy acting on
masses, which eventually is transferred to a target via the striker
plate. By storing energy through the compression of a compressible
fluid, we can store much more potential energy than can be obtained
by having a mass falling the equivalent distance as the height of
the compressed fluid chamber. We are effectively converting stored
energy into kinetic energy, rather than relying on gravity, and
this results in a more efficient use of space--allowing not only
for a much more compact unit to be built, but also for it to be
used on an angle, including horizontally or inverted; thereby
opening up many more applications for the invention.
[0047] By sequential energy release, and utilising the mass of the
primary piston assembly as an accelerated weight, we can harness
much more stored energy--two charges instead of one. As these
combine to accelerate the striker plate, we can achieve a much
higher velocity at the striker plate than a falling weight in a
compact unit. Since E.sub.k=1/2 mv.sup.2, velocity is the greater
contributor to energy than mass, which also means we can use less
mass and produce a lighter unit.
[0048] According to Newton's third law of motion, there is an equal
and opposite reaction on the accelerated mass of the primary piston
assembly as the primary piston fires. This results in a recoil
action. If the primary piston assembly was stationary when the
primary piston fired, then this may drive the remainder of the
primary piston assembly in the opposite direction by a distance
`x`. This distance would need to be accommodated into the design of
the apparatus. However, by firing the primary piston when the
primary piston assembly is moving, the recoil energy must first
stop the remainder of the primary piston assembly before it can
move it in the opposite direction. Hence the recoil distance is
less than `x`. This allows the designer to produce a unit which is
more compact. Also, it helps prevent the moving primary piston
assembly from slamming into the opposite end of the apparatus as it
is slowed, or even reversed, according to the precise parameters of
timing, geometries, pressurisation, mass, etc. which skilled reader
may incorporate into a specific design of an embodiment of the
present invention--there is a degree of user choice, and
flexibility of design here to allow a user to optimise the design
of their specific embodiment.
[0049] Hence, most of the energy can be delivered to the striker
plate, from a compact unit which is lighter and smaller than
traditional falling weight apparatus.
[0050] The nature of the invention will be more clearly seen from
the following illustrations, which are given by way of example
only.
DESCRIPTION OF DRAWINGS
[0051] FIG. 1 is a schematic cross-sectional drawing illustrating
one preferred embodiment of the invention, and
[0052] FIG. 2 is a schematic cross-sectional drawing illustrating
the embodiment of FIG. 1 and also illustrating fluid
connections.
DESCRIPTION OF PREFERRED EMBODIMENT
[0053] With reference to the drawings, and by way of example only,
we have a piston (J) able to slide with a cylinder (JJ). This open
ended cylinder is open to a reservoir area (JT) filled with
nitrogen (or other) gas and sealed off by a seal or piston (X).
[0054] Underneath the piston (J) is a fluid (typically hydraulic
fluid) reservoir (H) in communication (not shown) via a non-return
valve with another fluid reservoir (B) under floating piston (D).
The non-return valve allows fluid to travel from (H) to (B) but not
from (B) to (H).
[0055] In operation, and preparing for a strike (impact), hydraulic
fluid is introduced from (H) to (B). This then pushes piston (D)
upwardly acting against nitrogen (or other) gas within reservoir
(DT).
[0056] Reservoir area (B) is also open to the reservoir area (A)
underneath a floating valve (G), which seats (VS) against the
inside contours of middle cylinder (MC), by means of a further
conduit (not shown) incorporating a flow restrictor.
[0057] As valve (G) has a larger surface area exposed to fluid in
reservoir (A) than the surface area exposed to reservoir (B), and
there is also a bias spring (F) pushing it (G) closed against seat
(VS), the fluid in reservoir (B) cannot push valve (G) open.
[0058] By pushing oil from (H) to (B) and (A) the result is that
piston (D) pushes against the nitrogen gas in (DT). Typically the
uncompressed pressure may be around 50-300 Barr, and compressed
around 80 to 400 Barr.
[0059] By pushing oil into reservoir area (H) we not only force oil
into (B) and (A) but also start forcing piston (J) upwardly towards
reservoir area (JT). Piston (J) is connected by rod (L) to the
middle cylinder (MC) which also acts as a floating weight. The gas
in reservoir (JT) may be equalized to that within the outer
cylinder reservoir volume (OR) by virtue of floating piston (X) and
which typically converts (OR) into a large accumulator area. The
pressure within (JT) is typically around 10-20 Barr but may be
increased to 50-70 Barr, which is typically sufficient to support
the weight of everything connected to piston (J) should the device
be used on an angle or even inverted.
[0060] Hence, in preparation for striking we have introduced fluid
into reservoir volume (H) which raises piston (J) against the gas
in the reservoir volume (JT). This also pulls cylinder (MC) and
associated components with it, and also introduces fluid into
reservoir (B), and also into (A) via a conduit with a flow
restrictor, thereby closing valve (G) against its seat (VS). This
then results in piston (D) being forced upwardly against the
pressurized reservoir (DT).
[0061] In turn, piston (D) is connected by rod (M) to striker plate
(N), and thus also raises it.
[0062] Next we shall describe the striking sequence. Ideally the
volume (H) is not too big so that oil can be released rapidly via a
release conduit (not shown).
[0063] As the pressure from reservoir (H) is released, pressure
from within reservoir (JT) then pushes piston (J) down rapidly
along with all the connected components.
[0064] The non-return valve between reservoir (H) and reservoir (B)
prevents fluid from returning from (B) to (H) when the pressure
from reservoir (H) is released. Thus the pressure in reservoir (B)
does not alter.
[0065] As the middle cylinder (and weight) (MC) travels downs
towards gland (S), poppet valve(s) (R) strike the gland (S) and
releases pressure from within reservoir area (A).
[0066] As reservoir (B) is connected to (A) by a restricted
conduit, it can only slowly replenish reservoir (A). Accordingly
the pressure differential ((B) is higher than (A)) then pushes
valve (G) open and opens the valve at the seat (VS). This then
rapidly releases oil from reservoir from (B) into the lower
pressure of the outer casing area. The large opening at the valve
seat is able to release oil faster than a typical conduit porting
into the reservoir are. Consequently there is a very rapid release
of any pressure acting on the underside of piston (D) and thus the
pressurized gas within reservoir (DT) very quickly accelerates
piston (D), and its associated components (including striker plate
(N)), downwardly and so that it ultimately hits sliding plate (T)
resting on top the pile or post (POST).
[0067] However, in this preferred embodiment, we do get some recoil
from the pressure of nitrogen against weight (MC) as piston (D) is
accelerated downwardly, thereby slowing weight (K) so it doesn't
slam into gland (S). This can result in the capture of more energy
as this energy is transferred to striker plate (N) rather than
being wasted on cylinder/weight (MC) impacting gland (S). Also as
the tapered base (DB) of piston (B) starts to overlap with in
restricted cylinder portion (U) we also get reduced flow from
reservoir volume (B) which slows piston (D) and provides some
hydraulic cushioning before it strikes internal components within
the cylinder (MC).
[0068] FIG. 2 illustrates in standard schematic form the main
hydraulic fluid connections including pump connection (PM), tank
connection (TK), restrictor valve (RV) and non-return valve
(NRV).
[0069] For simplicity, the various conduits, for supplying and
controlling hydraulic fluid according to the above description,
have not been shown though it will be anticipated that a skilled
addressee of the art will be able to readily implement these.
[0070] This specification is also based on the understanding of the
inventor regarding the prior art. The prior art description should
not be regarded as being authoritative disclosure on the true state
of the prior art but rather as referencing considerations brought
to the mind and attention of the inventor when developing this
invention.
[0071] Aspects of the present invention have been described by way
of example only and it should be appreciated that modifications and
additions may be made thereto without departing from the spirit or
scope of the present invention as described herein.
[0072] It should also be understood that the term "comprise" where
used herein is not to be considered to be used in a limiting sense.
Accordingly, `comprise` does not represent nor define an exclusive
set of items, but includes the possibility of other components and
items being added to the list.
* * * * *