U.S. patent application number 11/208090 was filed with the patent office on 2006-04-27 for high energy impact-based material removal apparatus.
Invention is credited to James Richard Kingham.
Application Number | 20060086210 11/208090 |
Document ID | / |
Family ID | 46322478 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086210 |
Kind Code |
A1 |
Kingham; James Richard |
April 27, 2006 |
High energy impact-based material removal apparatus
Abstract
A material removal apparatus for removing a material from a
surface is provided. The material removal apparatus comprises a
frame having distal and proximal frame portions, the proximal frame
portion comprising a handle. A tool shaft is slidably mounted to
the frame, the tool shaft having proximal and distal shaft ends and
a longitudinal shaft axis. The tool shaft is movable between a
first shaft position and a second shaft position distal to the
first position. A tool head attached to the distal shaft end is
adapted for engaging the material to be removed. The material
removal apparatus also comprises an impulse delivery arrangement
attached to the frame. The impulse delivery arrangement is adapted
for selectively applying a discrete impulsive force to the proximal
shaft end.
Inventors: |
Kingham; James Richard;
(Wicomico Church, VA) |
Correspondence
Address: |
HUNTON & WILLIAMS LLP;Riverfront Plaza, East Tower
951 E. Byrd Street
Richmond
VA
23219-4074
US
|
Family ID: |
46322478 |
Appl. No.: |
11/208090 |
Filed: |
August 19, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10972283 |
Oct 25, 2004 |
|
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11208090 |
Aug 19, 2005 |
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Current U.S.
Class: |
81/45 |
Current CPC
Class: |
B25C 11/00 20130101;
E04D 15/003 20130101 |
Class at
Publication: |
081/045 |
International
Class: |
E04D 15/00 20060101
E04D015/00 |
Claims
1. A material removal apparatus for removing a material from a
surface, the material removal apparatus comprising: a frame having
distal and proximal frame portions, the proximal frame portion
comprising a handle; a tool shaft slidably mounted to the frame,
the tool shaft having proximal and distal shaft ends and a
longitudinal shaft axis, the tool shaft being movable between a
first shaft position and a second shaft position distal to the
first position; a tool head attached to the distal shaft end, the
tool head being adapted for engaging the material to be removed;
and an impulse delivery arrangement attached to the frame, the
impulse delivery arrangement being adapted for selectively applying
a discrete impulsive force to the proximal shaft end.
2. A material removal apparatus according to claim 1 wherein the
impulse delivery arrangement comprises an impactor adapted for
selectively contacting the proximal shaft end to apply the discrete
impulsive force thereto and means for accelerating the impactor to
a desired impact velocity with which the impactor contacts the
proximal shaft head.
3. A material removal apparatus according to claim 2 wherein the
impactor has a kinetic energy in a range of about 5 ft-lbf to about
1000 ft-lbf at the impact velocity.
4. A material removal apparatus according to claim 1 wherein the
apparatus is sized for carriage and use by a single human user.
5. A material removal apparatus according to claim 1 further
comprising means for biasing the tool shaft toward the first shaft
position.
6. A material removal apparatus according to claim 1 wherein the
impulse delivery arrangement comprises: an air cylinder having a
closed proximal cylinder end and a distal cylinder end intersected
by a longitudinal cylinder axis, the air cylinder being connectable
to a pressurized air source for fluid communication therewith; a
piston slidably disposed within the air cylinder so as to be
movable along the longitudinal cylinder centerline between a first
piston position and a second piston position distal to the first
position, wherein the piston and the air cylinder are configured so
that movement of the piston may be controlled through selective
introduction of compressed air into the air cylinder and wherein
the longitudinal shaft axis is substantially collinear with the
longitudinal cylinder axis and the first shaft position is
established so that the piston can make contact with the proximal
end of the tool shaft when the tool shaft is in the first position
and the piston is in a position intermediate the first and second
piston positions.
7. A material removal apparatus according to claim 6 wherein the
air cylinder has an inner cylindrical wall and the distal cylinder
end is open and wherein the tool shaft is mounted to the frame by
an annular cylindrical housing having proximal and distal housing
ends, the proximal end being disposed within the air cylinder and
being attached to the inner cylindrical wall so as to extend
distally from the distal cylinder end.
8. A material removal apparatus according to claim 7 wherein a
first portion of the tool shaft is slidably disposed through a
first bushing mounted to the inner cylindrical wall proximal to the
cylindrical housing and wherein a second portion of the tool shaft
is slidably disposed through a second bushing mounted within the
cylindrical housing
9. A material removal apparatus according to claim 7 wherein the
first portion of the tool shaft has a circular cross-section and
the second portion of the tool shaft has a non-circular
cross-section.
10. A material removal apparatus according to claim 7 further
comprising a seal mounted to the first bushing, the seal being
adapted to inhibit fluid leakage into or out of a portion of the
air cylinder proximal to the first bushing.
11. A material removal apparatus according to claim 3 further
comprising a control valve adapted for selectively controlling a
flow of compressed air from the compressed air source to the air
cylinder.
12. A material removal apparatus according to claim 3 further
comprising an air reservoir in selective fluid communication with
the air cylinder and being connectable to the compressed air
source.
13. A material removal apparatus according to claim 12 wherein the
air reservoir is integrally formed with the frame.
14. A material removal apparatus for removing a material from a
surface, the material removal apparatus comprising: a frame having
distal and proximal frame portions, the proximal frame portion
comprising a handle; a tool shaft slidably mounted to the frame,
the tool shaft having proximal and distal shaft ends and a
longitudinal shaft axis, the tool shaft being movable between a
first shaft position and a second shaft position distal to the
first position; a tool head attached to the distal shaft end, the
tool head being adapted for engaging the material to be removed;
impact means for selectively transferring an impact energy to the
proximal shaft head; and means for accelerating the impact means to
a desired impact velocity.
15. A material removal apparatus according to claim 14 wherein the
impact means comprises a piston.
16. A material removal apparatus according to claim 15 wherein the
means for accelerating comprises an air cylinder selectively
connectable to a compressed air source, the piston being slidably
disposed in the air cylinder for acceleration by said compressed
air.
17. A material removal apparatus according to claim 14 wherein the
impact energy is in a range of about 5 ft-lbf to about 1000
ft-lbf.
18. A material removal apparatus according to claim 14 wherein the
apparatus is sized for carriage and use by a single human user.
19. A material removal apparatus for removing a material from a
surface, the material removal apparatus comprising: a frame having
distal and proximal frame portions, the proximal frame portion
comprising a handle; an impulse delivery arrangement attached to
the frame, the impulse delivery arrangement comprising an air
cylinder having proximal and distal cylinder ends intersected by a
longitudinal cylinder axis and being connectable to a pressurized
air source, and a piston slidably disposed within the air cylinder
so as to be movable along the longitudinal cylinder centerline
between a first piston position to a second piston position distal
to the first position, the piston and the air cylinder being
configured so that movement of the piston may be controlled through
selective introduction of compressed air into the air cylinder; a
tool shaft slidably mounted to the frame, the tool shaft having
proximal and distal shaft ends and a longitudinal shaft axis that
is substantially collinear with the longitudinal cylinder axis, the
tool shaft being movable between a first shaft position and a
second shaft position distal to the first position, wherein the
first shaft position is established so that the piston can make
contact with the proximal end of the tool shaft when the tool shaft
is in the first position and the piston is in a contact position
intermediate the first and second piston positions; and a tool head
attached to the distal end of the tool shaft, the tool head being
adapted for engaging the material to be removed.
20. A material removal apparatus according to claim 19 wherein the
air cylinder has an inner cylindrical wall and the distal cylinder
end is open and wherein the tool shaft is mounted to the frame by a
an annular cylindrical housing having proximal and distal housing
ends, the proximal end being disposed within the air cylinder and
being attached to the inner cylindrical wall so as to extend
distally from the distal cylinder end.
21. A material removal apparatus according to claim 19 wherein the
piston has a kinetic energy in a range of about 5 ft-lbf to about
1000 ft-lbf when the piston is in the contact position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-in-Part of U.S.
application Ser. No. 10/972,283 filed Oct. 25, 2004, which is
incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The invention relates to the field of construction
equipment, and in particular relates to powered tools for removing
materials such as shingles or fasteners from surfaces, and for
demolition.
[0003] Shingles are frequently used to protect inclined roofs. The
shingles may be asphalt, or wood, or tiles, and may be attached to
the roof by nails or staples. Asphalt shingles faced with granular
stone are often nailed into overlapping rows, with the upper row
overlapping the lower row in order to keep out water. A layer of
tar paper may be underneath the shingles. The shingles and tar
paper are often attached to a wood roof. The wood roof often
comprises inclined plywood nailed onto rafters.
[0004] Shingles degrade with time and weather, and must be replaced
regularly. Old shingles and tar paper may be removed using many
types of manual tools such as: crowbar, hammer, shovel, and
pitchfork. Many nails are left behind after the shingles are
removed with these manual tools. Any remaining nails must be
removed after the shingles are removed. Thus, removing shingles is
very labor intensive, very expensive, and very slow.
[0005] Numerous attempts have been made to improve the removal of
shingles, felt, and nails from roof surfaces. For example, U.S.
Pat. No. 4,663,995 discloses a machine with a powered lifting plate
to lift the nails out. This machine requires the human operator to
physically push the machine into position before activating the
powered lifting plate. U.S. Pat. No. 4,709,479 discloses a powered
lifting plate to lift the felt and nails out, and also powered
wheels to simultaneously push the machine forward. U.S. Pat. Nos.
4,763,547 and 4,858,503 and 5,001,946 disclose various powered
lifting plates.
[0006] Another approach to the problem is to use a reciprocating
tool to strip materials from the roof surface. U.S. Pat. Nos.
5,076,119; 5,71,047; 5,741,047; and 6,393,948 each disclose a
reciprocating blade. U.S. Pat. No. 5,800,021 also discloses a
reciprocating blade, this time with the blade comprising
wedge-shaped teeth. U.S. Pat. No. 5,906,145 discloses the use of a
vibrating shovel blade.
[0007] None of the above solutions have proven to be completely
satisfactory. Most of the tools that have been used until now have
been bulky and difficult to manipulate. Many of them are usable
only to remove the shingles themselves without regard to the nails
holding them to the surface. In general, vibratory or reciprocating
tools are relatively ineffective for removing shingles and
fasteners from roofing surfaces.
SUMMARY OF THE INVENTION
[0008] An illustrative embodiment of the invention provides a
material removal apparatus for removing a material from a surface.
The material removal apparatus comprises a frame having distal and
proximal frame portions, the proximal frame portion comprising a
handle. A tool shaft is slidably mounted to the frame, the tool
shaft having proximal and distal shaft ends and a longitudinal
shaft axis. The tool shaft is movable between a first shaft
position and a second shaft position distal to the first position.
A tool head attached to the distal shaft end is adapted for
engaging the material to be removed. The material removal apparatus
also comprises an impulse delivery arrangement attached to the
frame. The impulse delivery arrangement is adapted for selectively
applying a discrete impulsive force to the proximal shaft end.
[0009] Another illustrative embodiment of the invention provides
another material removal apparatus for removing a material from a
surface. The material removal apparatus comprises a frame having
distal and proximal frame portions, the proximal frame portion
comprising a handle. The material removal apparatus also comprises
an impulse delivery arrangement attached to the frame. The impulse
delivery arrangement comprises an air cylinder having proximal and
distal cylinder ends intersected by a longitudinal cylinder axis
and being connectable to a pressurized air source. A piston is
slidably disposed within the air cylinder so as to be movable along
the longitudinal cylinder centerline between a first piston
position to a second piston position distal to the first position.
The piston and the air cylinder are configured so that movement of
the piston may be controlled through selective introduction of
compressed air from the pressurized air source into the air
cylinder. The material removal apparatus further comprises a tool
shaft slidably mounted to the frame. The tool shaft has proximal
and distal shaft ends and a longitudinal shaft axis that is
substantially collinear with the longitudinal cylinder axis. The
tool shaft is movable between a first shaft position and a second
shaft position distal to the first position. The first shaft
position is established so that the piston can make contact with
the proximal end of the tool shaft when the tool shaft is in the
first position and the piston is in a contact position intermediate
the first and second piston positions. A tool head attached to the
distal end of the tool shaft is adapted for engaging the material
to be removed.
[0010] Further objects, features and advantages of the invention
will be apparent from the detailed description below taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a graphic comparison of the force applied by
material removal devices according to the invention with the force
applied by a conventional air hammer;
[0012] FIG. 2 is a side view of a material removal apparatus
according to an embodiment of the invention;
[0013] FIG. 3 is a top view of the apparatus of FIG. 2;
[0014] FIG. 4 is a section view of a portion of a material removal
apparatus according to an embodiment of the invention;
[0015] FIG. 5 is a perspective view of a tool head that may be used
in conjunction with material removal apparatus according to an
embodiment of the invention;
[0016] FIG. 6A is a perspective view of a tool head that may be
used in conjunction with material removal apparatus according to an
embodiment of the invention;
[0017] FIG. 6B is a section view of the tool head of FIG. 6A;
[0018] FIG. 7 is a perspective view of a tool head that may be used
in conjunction with material removal apparatus according to an
embodiment of the invention;
[0019] FIG. 8A is a side view of a tool head that may be used in
conjunction with material removal apparatus according to an
embodiment of the invention;
[0020] FIG. 8B is a top view of the tool head of FIG. 8A;
[0021] FIG. 9 is a top view of a material removal apparatus
according to an embodiment of the invention; and
[0022] FIG. 10 is a section view of a portion of a material removal
apparatus according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides a relatively lightweight,
powered material removal apparatus that can be used to remove
materials such as shingles and nails from inclined roofs, and for
other removal and demolition tasks. The material removal apparatus
uses an impactor to deliver discrete high impact pulses to a tool
for removing materials from a surface. The use of a compressed air
driven piston as the impactor allows the delivery of high kinetic
energy and momentum to a tool shaft and tool head through an
impulsive impact. The kinetic energy and momentum from the tool
shaft is then transmitted to the material to be removed in a single
high energy stroke rather than multiple lower energy pulses
delivered through a generally vibrating or reciprocating motion.
The discrete high energy stroke of the removal tool of the
invention serves to force the tool head beneath the materials to be
removed. The tool head may be configured so that it may be
subsequently operated as a lever to lift the material from the
surface.
[0024] As discussed above, existing tools often use reciprocating
action for material removal. FIG. 1 illustrates the conceptual
difference between the material removal apparatus of the invention
and a reciprocating tool such as an air hammer. The material
removal apparatus of the invention applies a single, discrete high
energy impulsive force that may be two orders of magnitude higher
than the repetitive force applied by an air hammer of similar size.
This single, high energy pulse has been found to be more effective
for many material removal applications and, in pneumatic
embodiments, uses significantly less air than an air hammer.
[0025] The main components of a material removal apparatus
according to the invention will now be described. The tool head is
attached to the distal end of a tool shaft slidably mounted to a
housing or frame. The tool head and tool shaft may be separate
parts joined or removably attached to one another or may be formed
as a single integral part. The proximal end of the tool shaft
(i.e., the end nearer the user of the material removal apparatus)
is adapted for receiving an impulse load from a piston or other
actuator body. The frame or housing supports an impulse delivery
arrangement that is adapted for delivering a discrete impulse load
to the proximal end of the tool shaft upon demand. This load is
transmitted to the tool head, which is propelled distally along its
axis until it reaches a maximum stroke length or until it
encounters an obstruction. The energy imparted to the tool head is
transmitted to any materials or objects encountered by the tool
head during its stroke.
[0026] The material removal apparatus may have a stiff,
light-weight frame to which various components may be mounted. The
frame may also form an integral portion of various components, such
as the exterior wall of an air cylinder, or the exterior wall of an
air accumulator. In some embodiments, the frame may be replaced or
supplemented by a housing that serves to protect the working
components from the environment, and to protect the user from
injury caused by moving parts. The housing may also serve as a
portion of the working components. For example, the housing may
serve as the exterior wall of an air cylinder.
[0027] After the tool head is impulsively driven under or into the
material to be removed, the frame and the tool head may be used
together much like a conventional handle or pry bar for lifting up
the material. The frame may have a handle of any suitable shape,
e.g. a D-shaped or T-shaped handle, and may have an additional side
mounted tubular handle for guiding and controlling the material
removal apparatus manually.
[0028] In some embodiments of the invention, the impulse delivery
arrangement includes a compressed air-driven actuator comprising a
piston slidably disposed in an air cylinder. Compressed air may be
selectively introduced into the air cylinder through the use of a
multi-port valve. The air cylinder and piston are arranged and
mounted so that the piston travels along a path axially aligned
with the axis of the tool shaft. The piston and cylinder are
constructed so that a distal portion of the piston makes contact
with the proximal end of the tool shaft when the piston is at or
near the distal end of its stroke. The compressed air-driven
actuator may be a single-acting or double-acting actuator.
[0029] Mounting points may be provided on the frame for mounting
the air cylinder and valve, a trigger for selectively activating
the valve, and associated tubing. Guides incorporated into the
frame may be used to axially align the tool shaft with respect to
the air cylinder. The handle may have a trigger mechanism that
operates the multi-port valve used to control the airflow to the
air cylinder. The frame may have stops for limiting the travel of
the tool shaft.
[0030] Compressed air imparts great kinetic energy and momentum to
the piston. Near the end of its stroke, the piston provides a
hammering impulsive strike to a tool assembly. The hammering
impulsive strike of the piston against the tool assembly transfers
much or all of this kinetic energy and momentum to the tool
assembly. The tool assembly then transmits the hammering impulsive
strike to or under the material to be removed, similarly
transferring much or all of the kinetic energy and momentum to that
material.
[0031] As noted above, the tool assembly may comprise a tool shaft
and a tool head. The tool shaft may be slidably mounted to the
frame or housing using guides that provide axial alignment with the
piston shaft, and that allow movement in the axial direction. The
tool shaft may have a non-circular (e.g., elliptical or square or
other polygonal shape) cross section with the guides shaped in
complementary fashion so as to restrict rotational movement. This
assures that the rotational angle of the tool head may be fixed
relative the frame. The tool shaft may extend from the lower guide
of the frame.
[0032] In some embodiments, the tool head may be removably attached
to the tool shaft by means of pinning or other fastening method.
This allows for easy replacement of the tool head. Alternatively,
the tool head may be permanently attached to the tool shaft or
integrally formed therewith. The tool head may be configured in any
of a variety of forms tailored to particular uses. These may
include, without limitation, the end of a conventional roofing
shovel, a nail removal shovel blade with integral fulcrum, flat
bars, scrapers, wedges, punches, cutting blades, and specialty
application tools such as guided prying wedges or cutting tools
(e.g. a wedge with a channel shaped guide attached to the bottom of
the wedge to guide it along the top of a rafter when removing
sheathing).
[0033] In a particular embodiment, the tool head includes a
mounting tube adapted for receiving the distal end of the tool
shaft. The mounting tube may be fixed to the tool shaft using any
suitable bonding material or fastening mechanism. The distal-most
shaft guide may be configured with a larger diameter than the more
proximal guide(s) in order to accommodate the mounting tube. The
inserting of the tool shaft into the tool mounting tube effectively
increases the moment of inertia of the combined members to resist
bending.
[0034] In alternative embodiments, the impulse delivery arrangement
of the material removal apparatus may use an impactor driven by
sources of energy other than compressed air. These may include, for
example, pressurized liquids (hydraulics), chemical reactions, or
electricity, or other sources of energy. Chemical reactions may
include, without limitation: solid explosive charges similar to
those used in some nail guns, liquid explosive charges (e.g., a
fuel/air mixture). Electrical may include using a battery to
provide electricity. A a small gasoline burning piston engine may
be used provide mechanical power.
[0035] Many sources of energy may provide energy at relatively low
levels of power, and in these circumstances the impulse delivery
arrangement may accumulate the energy before delivering the energy
in an impulse. For example, a small light electric motor may slowly
compress a powerful spring.
[0036] In some embodiments, the material removal apparatus may
include a pressurizable air accumulator, which may be discharged
upon triggering the valve. This may reduce the pressure drop in the
compressed air line when the piston is triggered. The air
accumulator may be a separate vessel attached to the frame or may
be incorporated into the handle. The handle may also serve as a
manifold, routing air to and from the piston. In underwater use,
the exhausted air may be routed to the surface. Also in underwater
use, both sides of a double action piston may be at least slightly
pressurized in order to prevent water intrusion (i.e., operate
under positive pressure with respect to the external water
pressure).
[0037] A single acting piston reduces the number of exposed hoses,
does not need a pressure regulator, and is very reliable. The
single action piston, however, requires a restoring force to return
it to its initial position after delivering an impulse to the tool
shaft. The restoring force may be in the form of a spring, which
serves to bias the piston in its ready position adjacent the
proximal end of the air cylinder. A double acting piston requires
no return spring pressure to overcome and may be shorter and
lighter in weight. The exhaust return pressure can be controlled by
a pressure regulator which may reduce the impact of piston return,
and can be used underwater.
[0038] It will be understood that the bulk of the material removal
apparatus weight may be found near the upper end of the material
removal apparatus to provide the operator with better control and
ease of handling the apparatus.
[0039] Operation of exemplary embodiments of the present invention
will now be described. Any specific dimensions, angular
orientations or configurations depicted in the figures are for
representation of the exemplary embodiments herein and should not
be interpreted as limiting or restrictive to the scope of the
invention.
[0040] With reference to FIGS. 2-4, a material removal apparatus
100 according to an exemplary embodiment of the invention comprises
a frame 3, an impulse delivery arrangement 43, and a tool assembly
44. The frame 3 is structured to support the impulse delivery
arrangement 43 and the tool assembly 44. The frame 3 may be formed
from any type of lightweight structural members. In a preferred
embodiment, the frame is formed from one or more tubular members to
which the other components of the material removal apparatus may be
attached. In the illustrated embodiment, the frame 3 is formed as a
single elongate tubular member having a distal portion to which the
tool assembly 44 is attached, an intermediate portion to which the
impulse delivery arrangement 43 is attached and a proximal portion
40 that forms a handle for the user. The intermediate portion of
the frame 3 may have a curve 19 that serves to align the impulse
delivery arrangement 43 with the tool assembly 44.
[0041] The tool assembly 44 comprises a tool head 15 removably
attached to the distal end of a tool shaft 9. The tool shaft 9 is
an elongate member that is strong enough to receive an impulse load
and transmit it to the tool head 15 without bending and with
minimal energy loss. The tool shaft 9 may have a substantially
square cross-section. The tool head 15 includes a mounting tube 12
adapted for receiving the distal end of the tool shaft 9. The
mounting tube 12 is held in place on the end of the tool shaft 9 by
pins 11 or other removable fasteners. As will be discussed in more
detail below, the tool head 15 may be configured in a variety of
shapes to facilitate material removal.
[0042] The tool assembly 44 is held to the frame 3 by a plurality
of guides through which the tool shaft 9, the mounting tube 12 or
both the tool shaft 9 and the mounting tube 12 are slidably
disposed. In the illustrated embodiment, an upper portion of the
tool shaft 9 is disposed through a proximal guide 10 and the
mounting tube 12 is disposed through a distal shaft guide 16. The
shaft guides 10, 16 are configured to conform to and slidably
accommodate the tool shaft 9 and mounting tube 12 with minimal
friction and minimal play.
[0043] The impulse delivery arrangement 43 of the material removal
apparatus 100 includes an air cylinder 6 a multi-port valve 4, and
a trigger mechanism 2. The air cylinder 6 is an annular tube sealed
at its proximal end by a top cap 17 and at its distal end by a
bottom cap 18. The top cap 17 has a threaded port 20 adapted for
receiving fittings attached to the air supply tubing 5. O-rings 21
serve to seal the cap 17. The air cylinder 6 may also include a
bottom cap 18 that may contain holes 24 to let air in or out and a
shaft guide 25 to seal around and guide a piston shaft 8.
Additional O-rings 21 serve to seal the bottom cap 18.
[0044] A piston 52 may have a piston head 23 with a piston shaft 8
extending distally therefrom. The piston head 23 is adapted for
slidable disposition within the interior of the air cylinder 6 and
for sealing the portion of the air cylinder interior proximal to
the piston head 52. Piston rings 22 may be used to maintain the
seal. The piston head 23 is attached to the proximal end of the
piston shaft 8 which is slidably disposed through the shaft guide
25 so that the piston shaft 8 extends distally from the distal end
of the air cylinder 6.
[0045] The air cylinder 6 and piston 52 are configured and
positioned so that the piston shaft 8 is axially aligned with the
tool shaft 9. When the piston head 23 is in the initial or ready
position shown in FIG. 2, there is a gap between the distal end of
the piston shaft 8 and the proximal end of the tool shaft 9. When
compressed air is introduced through the port 20, the piston 52 is
forced to move rapidly in the distal direction relative to the air
cylinder 6. This causes the distal end of the piston shaft 8 to
make contact with the proximal end of the tool shaft 9 and transmit
an impulse load thereto.
[0046] The air cylinder 6 is attached to the frame 3 using a
plurality of brackets or other suitable mounting hardware. A
proximal mount 13 may be used to mount the top cap 17 to the frame
3 and a distal mount 14 may be used to mount the bottom cap 18.
[0047] The multi-port valve 4 of the impulse delivery arrangement
43 may be any suitable valve assembly that provides rapid cycling
for delivery of air from a compressed air source to the air
cylinder 6 through tubing 5. The multi-port valve 4 may be
electrically controlled by a trigger 2 mounted to the handle 40 or
elsewhere on the frame 3. Air may be delivered to the valve 4 using
any suitable tubing. Alternatively, the handle portion 40 of the
frame 3 may be configured as an air reservoir having an air inlet 1
and an outlet to which the valve 4 is in fluid communication.
[0048] As discussed above, the frame 3 may be configured for use as
a lever to pry up material. To facilitate this action, the material
removal apparatus 100 may include a fulcrum or engagement fixture
26 attached to the distal end of the frame. The engagement fixture
26 may be removably attached to the frame 3 with a fulcrum pin 27
or other removable fastener. Alternatively, the engagement fixture
may be permanently attached to the frame 3 or may be integrally
formed therewith.
[0049] The handle portion 40 of the frame 3 may be formed in a "D"
or "T" shape. The handle portion 40 may be attached to the other
portions of the frame 3 or may be integrally formed therewith.
[0050] As discussed above, the tool head may be formed in any of a
variety of configurations. FIGS. 5-8 are exemplary embodiments of
various configurations for the tool head 15. FIG. 5 illustrates a
crowbar-shaped tool head 15a that is useful for removing single
large nails, and for removing boards. FIGS. 6A and 6B illustrate a
chisel-shaped tool head 15b that is useful for breaking fasteners
such as small bolts. In this configuration, a channel 90 is formed
at the bottom of the tool head 15b for guiding the tool along a
rafter while removing sheathing, or guiding along a stud while
removing drywall. FIG. 7 illustrates a scraper-shaped tool head 15c
that is useful for removing adhesively attached tiles and tar paper
and for scraping ship hull surfaces. FIG. 8 illustrates a pointed
shovel shaped tool head 15d. This tool head 15d has a flat
horizontal component 92 to penetrate under shingles and a vertical
component 94 to act as a wedge to raise the shingles.
[0051] In an alternative embodiment of the invention, a material
removal apparatus uses an impulse delivery arrangement with a
compressed air driven impactor that is particularly well suited to
underwater use. With reference to FIGS. 9 and 10, a material
removal apparatus 200 according to this embodiment includes a frame
203, an impulse delivery arrangement 243, a tool assembly 244 and a
housing 233. As shown in FIG. 9, the frame 203 comprises an air
accumulator 232 that may be integrated into the handle portion 202
of the frame 203. For example, the air accumulator 232 may be a
hollow portion of the frame 203 that defines a chamber 234 that is
sealed to provide a pressurized reservoir for compressed air
introduced through the air inlet 201.
[0052] The chamber 234 of the air accumulator 232 is connected by
tubing 205 to a multi-port valve 204 and by separate tubing 207 to
a pilot valve 231. The multi-port valve 204 is connected to an air
cylinder 206 by an inlet tube 251 and an outlet tube 253. The
multi-port valve 204 is also connected to an exhaust tube 261, the
opposite end of which is open to the atmosphere.
[0053] The air cylinder 206 is an annular cylinder that is open at
its distal end and closed by a cylinder cap 255 at its proximal
end. The inlet tube 251 is connected by a fitting to the cylinder
cap 255 so that air can be passed into the air cylinder through a
cylinder inlet port 257. The outlet tube 253 is connected to the
air cylinder 206 near its distal end so that air can be passed out
of the air cylinder 206 through the cylinder outlet port 259. A
proximal portion of a cylindrical shaft housing 233 is fixedly
disposed within the distal end of the air cylinder 206. The
cylindrical housing is also attached to the frame 203.
[0054] A piston 223 is slidably disposed within the interior of the
air cylinder 206 so that when compressed air is introduced through
the inlet port 257 and/or removed through the outlet port 259 so as
to produce a pressure differential across the piston 223, the
piston 223 is forced to move in the distal direction. Conversely,
if air is introduced into the cylinder through the outlet port 259
and/or withdrawn from the inlet port 257, the piston 223 is forced
to move in the proximal direction. The piston 223 may be provided
with seals 242 to prevent the flow of air around the piston
223.
[0055] The multi-port valve 204 is configured to control the flow
of air into and out of the air cylinder 206 through the inlet and
outlet ports 257, 259. The multi-port valve 204 may be adapted to
control the air flow so that, for an impulse stroke, a large
pressure differential is established across the piston 223 so as to
produce a large acceleration of the piston 223 in the distal
direction. The multi-port valve 204 may also be adapted to control
the air flow so that, for a return stroke, a smaller pressure
differential is established across the piston 223 so as to produce
a smaller acceleration of the piston 223 in the proximal direction.
A pressure regulator (not shown) may be used to limit the pressure
differential on the proximal return stroke.
[0056] The outlet tube 253 may be a separate tube as shown in FIG.
9 or, alternatively, may be integrally formed with or bored into
the wall of the air cylinder 206. The air cylinder 206 may also
serve as a load bearing portion of the frame 203. In other
embodiments, the air cylinder 206 and outlet tube 253 may be
disposed within an outer housing that may be attached to or
included as a load-bearing part of the frame 203.
[0057] The tool assembly 244 includes a tool shaft 209 and a tool
head 215. The tool head 215 may be substantially similar to those
of earlier described embodiments. The tool shaft 209 is configured
and positioned so that its proximal end 260 is disposed within the
interior of the air cylinder 206 with its longitudinal axis aligned
with the air cylinder centerline 258. The tool shaft 209 may have a
broadened contact head 262 at its proximal end 260 to increase the
contact area between the piston 223 and the tool shaft 209 during
an impulse stroke. The tool shaft 209 may have a single
cross-sectional shape that may be circular, elliptical, square or
other geometric shape. In some embodiments, the tool shaft 209 may
have a plurality of shapes. In the embodiment illustrated in FIG.
10, the tool shaft 209 has a proximal portion 290 with a circular
cross-section and a distal portion 292 with a non-circular
cross-section.
[0058] The tool shaft 209 is slidably supported and aligned by a
plurality of bushings sized and shaped to conform to the
cross-section of the tool shaft 209. An air cylinder bushing 270 is
disposed within the interior of the air cylinder 206 distal to the
outlet port 259. The air cylinder bushing 270 is held in place by a
bushing retainer 271, which, in combination with a seal 272, serves
to seal the distal end of the air cylinder 206. The use of a
circular shaft cross-section and a circular air cylinder bushing
270 allows the tool shaft 209 to be selectively rotated relative to
the air cylinder 206.
[0059] One or more additional bushings may be disposed within the
shaft housing 233. In a particular embodiment, there is a proximal
shaft housing bushing 273 and a distal shaft housing bushing 276
fixedly attached to the interior wall of the housing 233. The
proximal shaft housing bushing 273 is held in place by a bushing
retainer 274. An optional seal 275 may be provided, which together
with the bushing retainer 274 seals the proximal end of the shaft
housing 233. The distal shaft housing bushing 276 is held in place
by a bushing retainer 277 and is configured to conform to the
non-circular shaft portion 292. As a result, the tool shaft 209
cannot be rotated relative to the shaft housing 233. The shaft
housing 233, however, may be mounted so that it can be rotated
relative to the air cylinder 206. By virtue of the non-circular
portion 292 of the tool shaft 209, rotation of the shaft housing
233 relative to the air cylinder 206 will also rotate the tool
shaft 209 relative to the air cylinder 206. This allows for easy
adjustment of the rotational angle of the tool head 215 while
maintaining an air-tight and water-tight seal of the air cylinder
206.
[0060] The material removal apparatus 200 may be activated through
the use of a control lever 229, which activates the pilot valve
231. The pilot valve 231 introduces air into the multi-port valve
204 for actuation thereof. Upon activation, the multi-port valve
204 establishes a pressure differential around the piston 223
causing it to accelerate and strike the contact head 262 of the
tool shaft 209 with an impulse load. The tool shaft 209 transmits
this load to the tool head 215 which imparts the impulse to the
material to be removed. Upon release of the control lever 229, the
multi-port valve 204 establishes a return differential pressure
around the piston 223 to cause the piston 223 to return to the
proximal end of the air cylinder 206.
[0061] The tool shaft 209 may be returned to its proximal position
by the action of the user in moving the entire material removal
apparatus 200 in the distal direction. If and when the tool head
215 encounters resistance to the distal movement (e.g., friction or
an obstruction), continued movement of the tool frame 203 in the
distal direction causes the tool head 215 and tool shaft 209 to
move proximally relative to the tool frame 203 and the impulse
delivery arrangement 243 until the tool shaft is in its proximal
position or until an additional impulse is applied.
[0062] In some embodiments, an automatic trigger arrangement may be
used to trigger additional impulse applications whenever the tool
shaft is returned to its proximal position as a result of
encountering resistance to distal movement of the tool head 215.
The trigger arrangement may include any switch mechanism (e.g., a
micro-switch) that closes to trigger the pilot valve 231 when the
tool shaft 209 is in a predetermined position relative to the frame
203 and/or the impulse delivery arrangement 243. When the impulse
is applied, the shaft 209 is moved distally away from this
predetermined position and the switch opens. In some such
embodiments, a biasing mechanism such as a spring may be used to
bias the tool shaft 209 away from the predetermined proximal
position so that the automatic trigger mechanism will only be
triggered upon the tool head 215 encountering a predetermined level
of resistance.
[0063] In alternative embodiments to the above, a biasing mechanism
may be used to bias the tool shaft 209 in the proximal direction.
This may serve to return the tool shaft more quickly to its
proximal position for repeated impulse application.
[0064] Because of its sealed impulse delivery arrangement, the
material removal apparatus 200 is particularly adapted for use in
an underwater environment. In addition, its double action air
cylinder provides for rapid reset of the device for application of
sequential discrete pulses to the material to be removed.
EXAMPLES
[0065] It will be understood that the material removal apparatus of
the present invention may be constructed and scaled to any size for
a particular application. In a typical hand-held, one-man material
removal apparatus according to the invention, the combined weight
of the tool shaft and tool head is in a range of about 1 pound and
to about 5 pounds. A typical impactor weight is also in a range of
about 1 pound and to about 5 pounds. In embodiments in which the
impactor is a compressed air-driven piston, the operating air
pressure may be in a range of about 30 psi to about 175 psi. The
piston diameter is typically from about 1 to about 3 inches and the
piston stroke is typically in a range from about 3 inches to about
9 inches.
[0066] An exemplary embodiment of a compressed air-driven material
removal apparatus according to the invention may be used to
illustrate the energy imparted to the tool head. The exemplary
material removal apparatus has a piston with a diameter of 3.0
inches and a piston stroke of 2.0 inches. The weight of the piston
is 2 pounds, and the combined weight of the tool shaft and tool
head is 2 pounds. The area of the top of the piston is equal to
3.14 times the square of the piston radius, which equals 7.06
square inches. The force acting on the piston equals the
cross-sectional area of the piston times the differential pressure
across the piston. For a differential pressure of 100 psi, the
force on the piston is 706 lbf. As the piston is accelerated
distally, it will have a kinetic energy level equal to the work
done in displacing it from its initial position; i.e.,
K.E.=Work=Force*Distance. Assuming an ideal one dimensional elastic
collision between the piston and the tool shaft, the maximum energy
that could be imparted to the tool shaft ("maximum impact energy")
can be calculated. The maximum impact energy will be achieved if
the collision occurs at the end of the full stroke length of the
piston. For a force of 706 lbf and a stroke of 2.0 inches, the
maximum impact energy is 118 ft-lbf.
[0067] A range of the maximum impact energy for a hand-held removal
tool can be established using the parameter ranges noted above. At
one end of the range, a material removal apparatus has a piston
diameter of 1.0 inch, a piston stroke of 3 inches, a piston weight
of 1 pound and a tool shaft/head weight of 1 pound. For an air
pressure differential of 30 psi, the maximum impact energy is 5.9
ft-lbf. At the other end of the range, a material removal apparatus
has a piston diameter of 3.0 inches, a piston stroke of 9 inches, a
piston weight of 5 pounds and a tool shaft/head weight of 5 pounds.
For an air pressure differential of 175 psi, the maximum impact
energy is 927 ft-lbf.
[0068] It can therefore be seen that a one man material removal
apparatus of the compressed air/piston type can achieve a maximum
impact energy in a range of about 5 ft-lbf to about 1000
ft-lbf.
[0069] It will be readily understood by those persons skilled in
the art that the present invention is susceptible to broad utility
and application. Many embodiments and adaptations of the present
invention other than those herein described, as well as many
variations, modifications and equivalent arrangements, will be
apparent from or reasonably suggested by the present invention and
foregoing description thereof, without departing from the substance
or scope of the invention.
[0070] While the foregoing illustrates and describes exemplary
embodiments of this invention, it is to be understood that the
invention is not limited to the construction disclosed herein. The
invention can be embodied in other specific forms without departing
from the spirit or essential attributes.
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