U.S. patent application number 10/715946 was filed with the patent office on 2005-05-19 for grinding apparatus for blending defects on turbine blades and associated method of use.
Invention is credited to Moeller, David B., Moeller, Dieter, Moeller, Heinz D..
Application Number | 20050107001 10/715946 |
Document ID | / |
Family ID | 34574314 |
Filed Date | 2005-05-19 |
United States Patent
Application |
20050107001 |
Kind Code |
A1 |
Moeller, Dieter ; et
al. |
May 19, 2005 |
GRINDING APPARATUS FOR BLENDING DEFECTS ON TURBINE BLADES AND
ASSOCIATED METHOD OF USE
Abstract
A grinding apparatus for use with an endoscope for viewing and
blending defects on a turbine engine blade is provided. In one
preferred embodiment air pulses from an air supply cause a grinding
head on the end of a grinding tool to reciprocate at a
predetermined speed. The position of the grinding head is fixed via
the operator via a trigger on the grinding tool which articulates
an outer portion of a support tube of the grinding tool. In another
preferred embodiment, fluid is used to reciprocate the grinding
head.
Inventors: |
Moeller, Dieter; (Mason,
OH) ; Moeller, Heinz D.; (Goshen, OH) ;
Moeller, David B.; (Goshen, OH) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER
441 VINE STREET
CINCINNATI
OH
45202
US
|
Family ID: |
34574314 |
Appl. No.: |
10/715946 |
Filed: |
November 18, 2003 |
Current U.S.
Class: |
451/6 |
Current CPC
Class: |
B24B 19/14 20130101;
B24B 27/027 20130101; F01D 5/005 20130101 |
Class at
Publication: |
451/006 |
International
Class: |
B24B 049/00 |
Claims
We claim:
1. A grinding tool for use with an endoscope for blending a defect
on a turbine blade inside a casing having an observation port, said
grinding tool comprising: a base unit having a trigger; a support
tube extending forwardly from said base unit and being sized to fit
through said observation port in said casing; an extension member
hingedly connected to said support tube and operatively coupled to
said trigger, wherein said trigger is used to change the position
of said extension member; a reciprocating piston located at least
partially in said extension member; and a grinding head coupled to
said reciprocating piston.
2. The grinding tool of claim 1 wherein said grinding head
reciprocates upon activation.
3. The grinding tool of claim 2 further comprising a motorized
driver for reciprocating said piston.
4. The grinding tool of claim 1 wherein said wherein said support
tube has an opening therethrough.
5. The grinding tool of claim 1 further comprising a spring
surrounding a portion of the piston.
6. A grinding tool for blending a defect on a turbine blade, said
grinding tool comprising: a base; a support tube extending
forwardly from said base, said support tube having a first portion
and a second portion fixed at an angle relative to said first
portion; and a reciprocating grinding head coupled to a piston at
least partially located in said second portion of said support tube
which is activated by an air source.
7. The grinding tool of claim 6 further comprising a trigger
connected to said base, said trigger being operatively coupled to
said second portion of said support tube so that movement of said
trigger causes movement of said second portion of said support
tube.
8. The grinding tool of claim 6 wherein said second portion of said
support tube is hingedly connected to said first portion of said
support tube.
9. A grinding tool for use with an endoscope for blending a defect
on a turbine blade inside a casing having an observation port, said
grinding tool comprising: a base unit; a support tube extending
forwardly from said base unit and being sized to fit through said
observation port in said casing, said support tube having an
opening therethrough at a forward end of said support tube through
which a portion of said endoscope may pass; an extension member
hingedly connected to said support tube and operatively coupled to
said base unit; means to change the position of said extension
member; a reciprocating piston located at least partially in said
extension member; and a grinding head coupled to said reciprocating
piston.
10. The grinding tool of claim 9 wherein said grinding head
reciprocates upon activation.
11. The grinding tool of claim 9 wherein said grinding head
reciprocates via a mechanical driver.
12. An apparatus for use with an endoscope for blending a defect on
a turbine blade located in a casing having an observation port,
said apparatus comprising: an air supply; a grinding tool
operatively coupled to said air supply, said grinding tool
comprising a base unit having a trigger; a support tube extending
forwardly from said base unit, said support tube having an opening
therethrough at a forward end of said support tube, said endoscope
being able to pass through said support tube and out said opening
in said support tube; an extension member hingedly connected to
said support tube and operatively coupled to said trigger, wherein
said trigger is used to change the position of said extension
member; and a grinding head coupled to a reciprocating piston at
least partially in said extension member, wherein said grinding
head is reciprocated via air pulses from said air supply.
13. The apparatus of claim 12 wherein the frequency of said air
pulses may be varied to change the speed of the reciprocation of
the grinding head.
14. The apparatus of claim 12 wherein said air supply is coupled to
said base unit of said grinding tool via an air supply line.
15. In combination, a grinding tool and an endoscope for blending a
defect on a turbine blade inside a casing having an observation
port, said combination comprising: a grinding tool having a base
unit including a trigger; a support tube extending forwardly from
said base unit, said support tube having an opening therethrough;
an extension member hingedly connected to said support tube and
operatively coupled to said trigger, wherein said trigger is used
to change the position of said extension member; a reciprocating
piston located in said extension member; a grinding head coupled to
said piston; and an endoscope having a portion extending through
said support tube of said grinding tool and out said opening in
said support tube.
16. The combination of claim 15 wherein said piston reciprocates in
response to air pulses from an air supply.
17. The combination of claim 15 further comprising a spring
surrounding a portion of said piston.
18. A method of blending a defect on a turbine blade inside a
casing having an observation port with a grinding apparatus
including a grinding tool, an endoscope and an air supply, said
method comprising: providing a grinding tool comprising a base and
trigger connected to said base, a support tube extending forwardly
from said base, said support tube having an opening therethrough at
a forward end of said support tube, an extension member hingedly
connected to said support tube and operatively coupled to said
trigger, wherein said trigger is used to change the position of
said extension member, a piston at least partially in said
extension member and a grinding head coupled to said piston;
passing a portion of said endoscope through said support tube of
said grinding tool and out said opening in said support tube;
passing said support tube through said observation port in said
casing; locating said defect on said turbine blade with said
endoscope; positioning said grinding head proximate said defect on
said turbine blade; and activating said air supply to supply air
pulses to reciprocate said piston and said grinding head.
19. The method of claim 18 wherein positioning said grinding head
proximate said defect on said turbine blade comprises moving said
extension member of said grinding tool via said trigger.
20. A method of blending a defect on a turbine blade inside a
casing having an observation port with a grinding apparatus
including a grinding tool, an endoscope and a air supply, said
method comprising: providing a grinding tool comprising a support
tube extending forwardly from a base, a piston adapted to move in
said support tube and a grinding head secured to said piston;
passing a portion of said endoscope through said support tube of
said grinding tool and out an opening in said support tube; passing
said support tube and portion of said endoscope through said
observation port in said casing; locating said defect on said
turbine blade using said endoscope; positioning said grinding head
proximate said defect on said turbine blade; and supplying air
pulses from said air supply to reciprocate said grinding head.
21. The method of claim 20 wherein said air pulses pass through an
air supply tube operatively coupled to said grinding tool.
22. The method of claim 20 wherein positioning said grinding head
proximate said defect on said turbine blade comprises moving a
portion of said support tube of said grinding tool via a trigger on
said grinding tool.
23. A method of blending a defect on a turbine blade inside a
casing having an observation port with a grinding apparatus
including a grinding tool and an endoscope, said method comprising:
providing a grinding tool comprising a base, and a trigger
connected to said base, a support tube extending forwardly from
said base, said support tube having an opening therethrough at a
forward end of said support tube, an extension member hingedly
connected to said support tube and operatively coupled to said
trigger, wherein said trigger is used to change the position of
said extension member and a grinding head coupled to said extension
member; passing said support tube and a portion of said endoscope
through said observation port in said casing; locating said defect
on said turbine blade using said endoscope; positioning said
grinding head proximate said defect on said turbine blade; and
supplying fluid to reciprocate said grinding head.
24. The method of claim 23 wherein positioning said grinding head
proximate said defect on said turbine blade comprises moving said
extension member of said grinding tool via said trigger.
25. A method of blending a defect on a turbine blade inside a
casing having an observation port with a grinding apparatus
including a grinding tool and an endoscope, said method comprising:
providing a grinding tool comprising a base unit having a trigger,
a support tube extending forwardly from said base unit, said
support tube having a first portion and a second portion
operatively coupled to said trigger; adjusting the position of said
second portion of said support tube relative to said first portion
of said support tube; passing said second portion of said support
tube through said observation port in said casing; locating said
defect on said turbine blade; positioning said grinding head
proximate said defect on said turbine blade; and reciprocating said
grinding head.
26. The method of claim 25 wherein positioning said grinding head
proximate said defect on said turbine blade comprises moving said
second portion of said support tube with said trigger.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to apparatus for blending
defects on turbine blades such as, for example, nicks and notches.
More particularly, this invention relates to a grinding apparatus
for blending defects on turbine blades using an endoscope to view
the defects through observation ports in an engine casing.
BACKGROUND OF THE INVENTION
[0002] Conventional gas turbine engines, such as those used in
aircraft, are enclosed in an engine casing and include a plurality
of turbine blades secured to a drum. Such gas turbine engines,
typically mounted on the wing of an aircraft, are frequently
damaged by foreign objects, such as sand particles, stones, or
other objects ingested by the engine during takeoff. These foreign
objects ingested by the air turbine engine often cause generally
V-shaped nicks or chips on impact along the leading edge of the
affected turbine blades. The process of replacing a turbine blade
is very expensive, so repair in place is desirable when compared to
replacement.
[0003] In order to prevent such notches or nicks from becoming more
pronounced and potentially cracking the turbine blade, it is
desirable to detect the nicks or notches early and, if possible,
repair or blend the defects in the turbine blades. In general the
term blending is used in the art for the process of smoothing a
V-shaped notch or nick into a more U-shaped configuration.
[0004] The detection process involves a visual inspection of each
turbine blade through a borescope or endoscope passed through
observation ports or holes in the engine casing. The borescope, a
fiber optic cable connected to a light source, is inserted through
borescope openings within the engine case and into the engine. The
small borescope openings are disposed throughout the engine case.
If a turbine blade having excessive damage is observed, the engine
must be removed from the wing of the aircraft, and then
disassembled to expose the damaged blade. Only then can the blade
be accessed and repaired or replaced. This procedure is
time-consuming and extremely expensive. Consequently, more
practical techniques for repairing or blending notches or defects
on an aircraft turbine blade have been developed.
[0005] One type of apparatus used to blend defects on turbine
blades in the manner described above uses a rotary grinding head or
tool located at the end of a blending tool. The tool may be passed
through the observation ports in the engine casing. U.S. Pat. Nos.
5,644,394; 5,803,680 and 5,475,485 disclose such apparatus. One
difficulty with tools using rotary heads is that the rotational
speed required to blend the defect is so high that the surface of
the turbine blade becomes very hot due to friction. Because most
turbine blades are made of titanium, the integrity of the titanium
may be compromised at high temperatures. The titanium metal may
actually melt or deform at high enough temperatures.
[0006] An alternative to a tool which rotates a grinding head is
disclosed in U.S. Pat. No. 5,102,221. This patent discloses an
apparatus for repairing or blending defects on a turbine blade
using a reciprocating motion, as opposed to a rotary motion. Again,
this apparatus is used with an endoscope. The apparatus disclosed
in this patent is difficult to use and subject to failure due to
the configuration and operation of the apparatus. Therefore, there
is a need for a grinding apparatus to blend defects on turbine
blades which is user-friendly and utilizes a reciprocating motion,
as opposed to a rotary motion.
SUMMARY OF THE INVENTION
[0007] One preferred embodiment of the present invention comprises
a grinding apparatus including two principal components: an
endoscope and a grinding tool operatively coupled to the endoscope.
Any commercially available endoscope may be use with the present
invention. One type of commercially available endoscope which has
proven to work satisfactorily with the present invention is
manufactured by Machidascope under model FBA-2.4-100 and may be
ordered at wwwv.machidascope.com.
[0008] In one preferred embodiment, the grinding tool is coupled to
a compressed air supply via an air supply line. Air pulses provided
by the air supply reciprocate a grinding head operatively coupled
to the grinding tool. In another preferred embodiment, fluid is
transported to the grinding tool via a supply line and functions to
reciprocate the grinding head. In yet another preferred embodiment,
a motorized driver is coupled to the grinding head and upon being
activated mechanically reciprocates the grinding head.
[0009] The grinding tool is adapted to be used with an endoscope
for blending a defect on a turbine blade inside a casing. The
grinding tool comprises a base unit having a base, a handle
extending downwardly from the base proximate the rear of the base,
and a trigger located in front of the handle and extending
downwardly from the base also. Although one configuration of base
unit is illustrated, the base unit may assume numerous other
configurations without departing from the spirit of this
invention.
[0010] The grinding tool further comprises a support tube extending
forwardly from the base unit and being sized to fit through an
observation port in the casing. The support tube in one preferred
embodiment has an opening at the forward end of the support tube,
so that an articulated end of the endoscope may pass through the
support tube and out the opening in the support tube.
[0011] In one preferred embodiment, an extension member is hingedly
connected to the forward end of the support tube and operatively
coupled to the trigger. Because the extension member is
mechanically connected to the trigger, an operator may change the
position of the extension member by moving the trigger, thereby
flexing the hinge. The extension member has a hollow interior in
which is located a piston and a spring surrounding a portion of the
piston. No matter what the position of the extension member, air
passes through the support tube and hinge to reciprocate the piston
in the extension member.
[0012] A cylindrical grinding head is coupled to a forward end of
the piston and upon activation reciprocates at a predetermined
speed. Pulses of air supplied by the source of compressed air and
pushed through an air supply line to the grinding tool push the
piston against the bias of the spring in the extension member,
causing the spring to compress. When the burst or pulse of air is
exhausted, the spring forces the piston back to its original
position. In this manner, the spring goes through a cycle of
compression and noncompression as the piston reciprocates in
response to the air pulses. Other means of reciprocating the
grinding head may be used if desired.
[0013] In another preferred embodiment of the present invention,
the support tube comprises a first linear portion having an opening
therein so that the forward end of the endoscope can pass through
the opening in the support tube and enable the operator to view the
turbine blade. The support tube further comprises a second linear
portion hingedly connected to the first portion and operatively
coupled to the trigger so that movement of the trigger causes
movement of the second portion of the support tube. A piston and
spring arrangement like the one described above are located in the
second movable portion of the support tube. A reciprocating
grinding head is coupled to the piston.
[0014] Although the present invention preferably has a hinge
incorporated into the support tube, it is within the contemplation
of the present invention that the support tube lack a hinge. In
such an embodiment, the support tube is preferably bent but may
assume any desired configuration. In this situation, a second
portion of the support tube is fixed at an angle, preferably an
acute angle, relative to the first linear portion of the support
tube.
[0015] In use, a defect on a turbine blade may be blended or
smoothed using the grinding apparatus of the present invention. The
first step in utilizing the grinding apparatus of the present
invention is to couple a commercially available endoscope to the
grinding tool. This is accomplished by passing a portion of the
endoscope, including the lens end, through the base of the grinding
tool, through the support tube of the grinding tool and out an
opening in the support tube. When coupled to a light source, the
endoscope enables the operator to view inside the engine
casing.
[0016] Then the support tube of the grinding tool, with the
endoscope passing therethrough, is passed through an observation
port or hole in the engine casing. Using the endoscope, the
operator locates a defect on the turbine blade by visual scanning.
The operator then uses the trigger on the grinding tool to position
the grinding head proximate to the defect on the turbine blade.
Then a driver is activated to supply air pulses to the grinding
tool via the air supply line. The air pulses pass through the
support tube of the grinding tool and contact the piston, causing
the piston and grinding head of the grinding tool to reciprocate at
a desired speed. The frequency of the air pulses may be varied as
desired by any known means to change the speed of reciprocation of
the grinding head. If desired, the air pulses may be used to rotate
rather than reciprocate the grinding head.
[0017] In another preferred embodiment of the present invention,
fluid is used to reciprocate the grinding head. The fluid is
provided via a fluid supply and passed through a supply tube to the
grinding tool to reciprocate the grinding head. Any means such as a
motorized pump may be used to supply fluid to the grinding
tool.
[0018] In another preferred embodiment of the present invention, a
wire is used to reciprocate the grinding head. The wire is
operatively coupled at one end to a motorized driver such as a
variable speed motor, passed through the grinding tool and coupled
to a piston which is secured to the grinding head. Activation of
the motorized driver reciprocates the grinding head. Any means such
as a cam driven by a motor may be used to reciprocate the wire
operatively coupled to the grinding tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of the grinding apparatus of
the present invention used in conjunction with an endoscope;
[0020] FIG. 1A is a cross-sectional view taken along the line 1A-1A
of FIG. 1;
[0021] FIG. 2 is a side elevational view of one preferred
embodiment of the grinding tool of the present invention; and
[0022] FIG. 3 is a side elevational view partially in cross section
of a portion of the grinding tool of FIG. 2;
[0023] FIG. 3A is a cross-sectional view taken along the line 3A-3A
of FIG. 3;
[0024] FIG. 4 is a perspective view of an alternative embodiment of
grinding apparatus of the present invention used in conjunction
with an endoscope; and
[0025] FIG. 5 is a perspective view of another alternative
embodiment of grinding apparatus of the present invention for use
with an endoscope.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring to the drawings and particularly to FIG. 1, there
is illustrated a grinding apparatus 10 including an air supply 12,
an air supply line 13 and a grinding tool 14 for use with an
endoscope 16. The endoscope 16 has an eyepiece 17 at the end of a
tube 19 and an articulated lens end 20 moveable via movement of a
lever 18 on the eyepiece 17, as is known in the art. Any other sort
of viewer such as a video viewer may be used in place of the
eyepiece 17 to view or display data. Preferably, the endoscope 16
is used with a light source 22. Although one type of endoscope is
illustrated and described, the grinding apparatus 10 may be used
with many different types of endoscopes.
[0027] The grinding apparatus 10 of the present invention is used
for blending or retouching a defect, notch or nick 24 along the
leading edge 26 of a turbine blade 28 secured to a drum 30 (only
partially shown) in a manner known in the art. The drum 30 and
turbine blades 28 attached thereto are mounting in an engine casing
32 having a plurality of observation ports 34, as is known in the
art.
[0028] As best illustrated in FIG. 1, the air supply 12 may include
any known means to provide air pulses and push them through the air
supply line 13 to the grinding tool 14.
[0029] As best illustrated in FIG. 1, the grinding tool 14
comprises a base unit 36 including a base 38, a handle 40 and a
trigger 42. The base 38 is preferably made of metal but may be made
of any material. The base 38 has a top wall 44, a bottom wall 46, a
front wall 48, a rear wall 50 and a pair of opposed side walls 52.
The handle 40 extends downwardly from the bottom wall 46 of the
base 38 proximate the rear wall 50 of the base 38. Similarly, the
trigger 42 extends downwardly from the bottom wall 46 of the base
38 in front of the handle 40. Although one configuration of base
and base unit are illustrated and described, other configurations
of bases and base units may be utilized without departing from the
present invention. For example, the handle and/or trigger may be
located at a different location. Alternatively, the handle may be
omitted and/or the trigger replaced with other apparatus.
[0030] The grinding tool 14 further comprises a support tube 54
extending forwardly from the base 38. As shown in FIG. 1A, the
support tube 54 has a circular wall 56 having an outer surface 58
and an inner surface 60. The interior 62 of the support tube 54 is
hollow and divided into an upper portion 5 and a lower portion 6 by
a divider or guide 7. As shown in FIG. 1A, the endoscope tube 19
passes through the lower portion 6 as shown in FIG. 1A. As
illustrated in FIG. 2, the support tube wall 56 has an opening 64
at a forward end 66 of the support tube 54. The articulating end 20
of the endoscope 16 protrudes through this opening 64 in a manner
shown in FIG. 1 to enable the operator to view inside the engine
casing wall 32. To couple or join the endoscope 16 with the
grinding tool 14 of the present invention, the articulating lens
end 20 of the endoscope 16 is passed through a hole 68 in the rear
wall 50 of the base 38, through the base 38 and then through the
lower portion 6 of the support tube 54 before exiting the opening
64 in the support tube wall 56.
[0031] In a first preferred embodiment, an extension member 70 is
coupled or joined to the support tube 54 via hinge 72. The hinge 72
pivots about an axis 73 and is coupled or joined to the support
tube 54 and the extension member 70. See FIG. 1. FIG. 3 illustrates
in detail one form of hinge 72; however, any other type of suitable
hinge may be used in accordance with the present invention.
[0032] In one preferred embodiment of the present invention, the
extension member 70 is preferably a linear piece of tubing, made of
metal, plastic or any other suitable material. As seen in FIG. 3,
the extension member 70 has a circular wall 74 having an outer
surface 76 and an inner surface 78. However, the extension member
70 may assume other configurations without departing from the
spirit of the present invention. If desired, the extension member
70 may be considered a second portion of the support tube hingedly
connected to a first linear portion of the support tube. If
desired, the hinge may be omitted and the second portion of the
support tube fixed in position relative to the first portion of the
support tube.
[0033] The extension member 70 is operatively coupled to the
trigger 42 so that the operator may move the extension member 70 by
moving the trigger 42. In one preferred embodiment, at least one
wire 80 (shown in cross section in FIG. 1A) is secured at one end
82 to the extension member 70 via welding or any other suitable
method and secured at the other end (not shown) to the trigger 42.
See FIG. 3. The wire 80 extends the length of the support tube 54
on the inside thereof. Although this is one mechanical way of
coupling the trigger 42 and extension member 70 so that the
extension member 70 may be mechanically moved to its desired
position, other methods of coupling the trigger and extension
member may be utilized. As shown in FIG. 2, the trigger 42 may be
moved from a first position shown in dashed lines to a second
position shown in solid lines which causes the extension member 70
to move from an extended or first position shown in dashed lines in
FIG. 2 to a bent or second position shown in solid lines in FIG.
2.
[0034] As shown in FIG. 3A, the hinge 72 has an outer wall 71
inside which wire 80 passes. In addition, an air tube 92 passes
through the hinge 72 inside the hinge outer wall 71. The air tube
92 is a flexible piece of tubing having an outer tube wall 93,
preferably made of plastic, which extends from an air stop 55 in
the support tube 54 to a piston 86 in the extension member 70. See
FIGS. 3 and 3A.
[0035] As shown in FIG. 1A, the support tube 54 has an air stop 55
at the forward end 66 of the support tube 54 which reduces the
diameter through which the air flows as air passes through the
hinge 72. The air stop 55 has an opening 94 through which the air
tube 92 passes and another opening 96 through which the wire 80
passes. See FIG. 1A. If desired, two or more wires or other
structures may be used in accordance with the present
invention.
[0036] As shown in FIG. 3, a piston 86 is located at least
partially inside the extension member 70 and moveable therein in
reaction to the pulses of air from the air supply 12. The piston 86
has a base portion 100 and an finger portion 102 extending
forwardly from the base portion 100. The base portion 100 of the
piston 86 has a diameter approximately equal to the inner diameter
of the extension member 70 so that air may not get through the
extension member 70 without moving the piston 86. A spring 104
surrounds the finger portion 102 of the piston 86 inside the
extension member 70 as shown in FIG. 3. The spring 104 extends
between a stop 106 at the forward end 108 of the extension member
70 and the base portion 100 of the piston 86. When a pulse of air
passes through the tube 92, the air exerts force or pressure on the
base portion 100 of the piston 86, moving the base portion 100 of
the piston 86 forwardly against the bias or force of the spring
104, thereby compressing the spring 104 against the stop 106 in the
extension member 70. Once the pressure from the air pulse is
relaxed or extinguished, the spring 104 pushes the piston 86 back
to its original position in which the base portion 100 of the
piston 86 abuts a stop 110 in the extension member 70. In this
manner the spring 104 cycles between a compressed position and a
relaxed position in response to the air pulses generated in the air
supply 12 and passed through the air supply line 13 to the grinding
tool 14.
[0037] A grinding head 112 is coupled to the finger portion 102 of
the piston 86 outside of the extension member 70 in a manner shown
in detail in FIG. 3. The grinding head 112 is preferably
cylindrical but may be other shapes or configurations. Any suitable
means of securing the grinding head 112 to the finger portion 102
of the piston 86 may be used.
[0038] In use, the endoscope 16 is coupled or joined to the
grinding tool 14 by passing the lens end 20 of the endoscope 16
through the opening 68 in the base 38 of the endoscope, through the
base 38 of the grinding tool 14, through the support tube 54 of the
grinding tool 14 and out the opening 64 in the support tube wall
56. A light source 22 is coupled to the endoscope 16 in a manner
known in the art either before or after the endoscope 16 is coupled
to the grinding tool 14. The operator then passes the support tube
54 of the grinding tool 14 with a portion of the endoscope 16
therethrough through one of the observation ports 34 in the engine
casing 32. The operator then uses the endoscope 16 to locate a
defect 24 along the leading edge 26 of a turbine blade 28. The
operator then positions the grinding head 112 proximate the defect
24 and activates the air supply to provide air pulses to the
grinding tool 14. The operator uses the trigger 42 to move the
extension member 70 and grinding head 112 via the hinge 72 in the
manner described above. The air pulses reciprocate the piston 86 in
the extension member 70 of the grinding tool 14. The reciprocation
of the piston 86 causes the grinding head 112 to reciprocate
because the piston 86 and grinding head 112 are joined
together.
[0039] An alternative preferred embodiment of the present invention
is illustrated in FIG. 4. For the sake of simplicity, like numerals
will be used to describe like parts but with a letter "a"
designation. In this preferred embodiment, fluid is used rather
than air to reciprocate a grinding head 112a secured to the end of
an extension member or portion of a support tube 70a. Any method of
securing the grinding head 112a to the end of the extension member
70a may be used. A piston 114 pushes and pulls fluid from a fluid
supply 116 through tube 118 to the grinding tool 14a. The fluid
passes through the support tube 54a including hinge 72a to a piston
(not shown). The back and forth movement of the fluid in the
grinding tool 14a reciprocates the piston (not shown) to which is
connected grinding head 112a. In many respects, the grinding tool
14a is similar to the grinding tool 14 described above, except
fluid rather than air is used to reciprocate the grinding head.
[0040] An alternative preferred embodiment of the present invention
is illustrated in FIG. 5. For the sake of simplicity, like numerals
will be used to describe like parts but with a letter "b"
designation. In this preferred embodiment, a mechanical driver is
used rather than air or fluid to reciprocate a grinding head 112b
hingedly secured to the end of an extension member 70b or portion
of a support tube 54b with hinge 72b. Any method of securing the
grinding head 112b to the end of the extension member 70b may be
used. A motorized driver 118 pulls a wire 120 extending through the
support tube 54b of the grinding tool 14a around a pulley 124 and
secured to a piston 86b located in extension member 70b. Extension
member 70b is hingedly connected to the support tube 54b in any
operable manner. A grinding head 112b is secured to the piston 86b
in any suitable manner or fashion. A spring 122 located inside the
extension member 70b pushes the piston 86b back outwardly after the
tension on the wire 120 is partially relaxed. The back and forth
movement of the piston 86b due to the motorized driver 118, wire
120 and spring 122 causes the grinding head 112b to reciprocate. In
many respects, the grinding tool 14b is similar to the grinding
tool 14 described above, except a motorized driver in concert with
a spring causes the grinding head to reciprocate.
[0041] It is to be understood that various changes and
modifications may be made to the preferred embodiments discussed
above without departing from the scope of the present invention,
which is defined by the following claims and equivalents thereof.
For example, with any of the embodiments described herein, the
grinding head may be rotated rather than reciprocated.
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