U.S. patent application number 15/434386 was filed with the patent office on 2018-08-16 for object with tear-shaped suspension for annular bodies.
The applicant listed for this patent is General Electric Company. Invention is credited to Heath Michael Ostebee, Timothy James Purcell, Lucas John Stoia.
Application Number | 20180231253 15/434386 |
Document ID | / |
Family ID | 63104534 |
Filed Date | 2018-08-16 |
United States Patent
Application |
20180231253 |
Kind Code |
A1 |
Purcell; Timothy James ; et
al. |
August 16, 2018 |
OBJECT WITH TEAR-SHAPED SUSPENSION FOR ANNULAR BODIES
Abstract
An object includes an annular outer body having an interior
surface; and an annular inner body disposed inside the annular
outer body, the annular inner body having an exterior surface
defining an annular passage with the interior surface of the
annular outer body. A plurality of suspension elements connects the
interior surface of the annular outer body to the exterior surface
of the annular inner body, each suspension element configured to
substantially rigidly locate a position of the annular outer body
relative to the annular inner body in axial and lateral directions
while permitting controlled deflection in a radial direction. Each
suspension element has an at least partially tear-shaped
cross-section.
Inventors: |
Purcell; Timothy James;
(Centerville, OH) ; Ostebee; Heath Michael;
(Easley, SC) ; Stoia; Lucas John; (Taylors,
SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
63104534 |
Appl. No.: |
15/434386 |
Filed: |
February 16, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 3/283 20130101;
F23R 2900/00018 20130101; F23D 11/38 20130101 |
International
Class: |
F23R 3/28 20060101
F23R003/28 |
Claims
1. An object, comprising: an annular outer body having an interior
surface; an annular inner body disposed inside the annular outer
body, the annular inner body having an exterior surface defining an
annular passage with the interior surface of the annular outer
body; and a plurality of suspension elements connecting the
interior surface of the annular outer body to the exterior surface
of the annular inner body, each suspension element configured to
substantially rigidly locate a position of the annular outer body
relative to the annular inner body in axial and lateral directions
while permitting controlled deflection in a radial direction, and
wherein each suspension element has an at least partially
tear-shaped cross-section.
2. The object of claim 1, wherein each suspension element includes
a first end coupled to the annular inner body and a
circumferentially spaced, second end coupled to the annular outer
body.
3. The object of claim 2, wherein the first end couples to the
annular inner body at a first angle between 85.degree. and
95.degree., and the second end couples to the annular outer body at
a second angle between 85.degree. and 95.degree..
4. The object of claim 2, wherein the annular outer body extends
parallel to a centerline axis and each suspension element has an
S-shape viewed in the direction of the centerline axis.
5. The object of claim 4, wherein each suspension element extends a
distance parallel to the centerline axis.
6. The object of claim 4, wherein the first end of each respective
suspension element is within 5.degree. of the circumferentially
spaced, second end of an adjacent suspension element as measured
relative to the centerline.
7. The object of claim 1, wherein the plurality of suspension
elements are circumferentially spaced between the interior surface
of the annular outer body and the exterior surface of the annular
inner body.
8. The object of claim 1, wherein the annular inner body includes
an outer, combustible fuel carrying element of a fuel nozzle, and
the annular outer body includes a heat shield for the fuel nozzle,
and wherein a space between the interior surface of the annular
outer body and the exterior surface of the annular inner body
carries a coolant therethrough.
9. A fuel nozzle, comprising: an annular outer heat shield having
an interior surface; an annular inner body disposed inside the
annular outer heat shield, the annular inner body having an
interior for delivering a combustion material and an exterior
surface defining an annular passage with the interior surface of
the outer heat shield; and a plurality of suspension elements
connecting the interior surface of the outer heat shield to the
exterior surface of the annular inner body, each suspension element
configured to substantially rigidly locate a position of the outer
heat shield relative to the annular inner body in axial and lateral
directions while permitting controlled deflection in a radial
direction, and wherein each suspension element has an at least
partially tear-shaped cross-section.
10. The fuel nozzle of claim 9, wherein each suspension element
includes a first end coupled to the annular inner body and a
circumferentially spaced, second end coupled to the outer heat
shield.
11. The fuel nozzle of claim 10, wherein the first end couples to
the annular inner body at a first angle between 85.degree. and
95.degree., and the second end couples to the outer heat shield at
a second angle between 85.degree. and 95.degree..
12. The fuel nozzle of claim 10, wherein the outer heat shield
extends parallel to a centerline axis and each suspension element
has an S-shape viewed in the direction of the centerline axis.
13. The fuel nozzle of claim 12, wherein each suspension element
extends a distance parallel to the centerline axis.
14. The fuel nozzle of claim 12, wherein the first end of each
respective suspension element is within 5.degree. of the
circumferentially spaced, second end of an adjacent suspension
element measured relative to the centerline.
15. The fuel nozzle of claim 9, wherein the plurality of suspension
elements are circumferentially spaced between the interior surface
of the outer heat shield and the exterior surface of the annular
inner body.
16. The fuel nozzle of claim 9, wherein a space between the
interior surface of the outer heat shield and the exterior surface
of the annular inner body carries a coolant therethrough.
17. The fuel nozzle of claim 16, wherein the at least partially
tear-shaped cross-section includes a leading edge facing a
direction of flow of the coolant.
18. A non-transitory computer readable storage medium storing code
representative of an object, the object physically generated upon
execution of the code by a computerized additive manufacturing
system, the code comprising: code representing the object, the
object including: an annular outer body having an interior surface;
an annular inner body disposed inside the annular outer body, the
annular inner body having an exterior surface defining an annular
passage with the interior surface of the annular outer body; and a
plurality of suspension elements connecting the interior surface of
the annular outer body to the exterior surface of the annular inner
body, each suspension element configured to substantially rigidly
locate a position of the annular outer body relative to the annular
inner body in axial and lateral directions while permitting
controlled deflection in a radial direction, wherein each
suspension element has an at least partially tear-shaped
cross-section.
19. The storage medium of claim 18, wherein each suspension element
includes a first end coupled to the annular inner body and a
circumferentially spaced, second end coupled to the annular outer
body.
20. The storage medium of claim 18, wherein each suspension element
extends a distance parallel to the centerline axis.
Description
BACKGROUND OF THE INVENTION
[0001] The disclosure relates generally to manufacturing annular
bodies, and more particularly, to an object with a tear-shaped
suspension for annular bodies such as those used in fuel
nozzles.
[0002] Annular bodies are used in a wide variety of industrial
settings in which the bodies must be positioned relative to one
another and withstand a range of environmental changes. One
application in which such structures are employed are fuel nozzles
such as those employed on gas turbines. In this setting, a number
of generally concentric annular bodies create passages therebetween
to deliver combustion materials such as fuel(s) and/or air to a
combustion chamber. In order for the fuel nozzle to remain
thermally compliant, i.e., maintain positioning, physical
integrity, etc., an annular outer heat shield is oftentimes formed
about the outermost annular body of the fuel nozzle. Typically, the
fuel nozzle annular bodies are configured to be stiff axially
relative to a centerline thereof, but radially pliant.
BRIEF DESCRIPTION OF THE INVENTION
[0003] A first aspect of the disclosure provides an object,
comprising: an annular outer body having an interior surface; an
annular inner body disposed inside the annular outer body, the
inner body having an exterior surface defining an annular passage
with the interior surface of the annular outer body; and a
plurality of suspension elements connecting the interior surface of
the annular outer body to the exterior surface of the inner body,
each suspension element configured to substantially rigidly locate
a position of the annular outer body relative to the inner body in
axial and lateral directions while permitting controlled deflection
in a radial direction, and wherein each suspension element has an
at least partially tear-shaped cross-section.
[0004] A second aspect of the disclosure provides a fuel nozzle,
comprising: an annular outer heat shield having an interior
surface; an annular inner body disposed inside the outer heat
shield, the inner body having an interior for delivering a
combustion material and an exterior surface defining an annular
passage with the interior surface of the outer heat shield; and a
plurality of suspension elements connecting the interior surface of
the outer heat shield to the exterior surface of the inner body,
each suspension element configured to substantially rigidly locate
a position of the outer heat shield relative to the inner body in
axial and lateral directions while permitting controlled deflection
in a radial direction, and wherein each suspension element has an
at least partially tear-shaped cross-section.
[0005] A third aspect of the disclosure provides a non-transitory
computer readable storage medium storing code representative of an
object, the object physically generated upon execution of the code
by a computerized additive manufacturing system, the code
comprising: code representing the object, the object including: an
annular outer body having an interior surface; an annular inner
body disposed inside the annular outer body, the inner body having
an exterior surface defining an annular passage with the interior
surface of the annular outer body; and a plurality of suspension
elements connecting the interior surface of the annular outer body
to the exterior surface of the inner body, each suspension element
configured to substantially rigidly locate a position of the
annular outer body relative to the inner body in axial and lateral
directions while permitting controlled deflection in a radial
direction, and wherein each suspension element has an at least
partially tear-shaped cross-section.
[0006] The illustrative aspects of the present disclosure are
designed to solve the problems herein described and/or other
problems not discussed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] These and other features of this disclosure will be more
readily understood from the following detailed description of the
various aspects of the disclosure taken in conjunction with the
accompanying drawings that depict various embodiments of the
disclosure, in which:
[0008] FIG. 1 shows a block diagram of an additive manufacturing
process including a non-transitory computer readable storage medium
storing code representative of an object according to embodiments
of the disclosure.
[0009] FIG. 2 shows a perspective view of an illustrative object
including a suspension elements, according to embodiments of the
disclosure.
[0010] FIG. 3 shows a cross-sectional view of the illustrative
object of FIG. 2 along line 3-3.
[0011] FIG. 4 shows an enlarged cross-sectional view of the object
of FIG. 3.
[0012] FIG. 5 shows a perspective view of an end of an object
including suspension elements, in accordance with embodiments of
the disclosure.
[0013] FIG. 6 shows an end view of an object including suspension
elements, in accordance with embodiments of the disclosure.
[0014] FIG. 7 shows a cross-sectional view of one illustrative
suspension element including an at least partially airfoil
cross-section, according to embodiments of the disclosure.
[0015] It is noted that the drawings of the disclosure are not to
scale. The drawings are intended to depict only typical aspects of
the disclosure, and therefore should not be considered as limiting
the scope of the disclosure. In the drawings, like numbering
represents like elements between the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0016] As an initial matter, in order to clearly describe the
current disclosure it will become necessary to select certain
terminology when referring to and describing relevant machine
components within an object, illustrated as a fuel nozzle herein.
When doing this, if possible, common industry terminology will be
used and employed in a manner consistent with its accepted meaning.
Unless otherwise stated, such terminology should be given a broad
interpretation consistent with the context of the present
application and the scope of the appended claims. Those of ordinary
skill in the art will appreciate that often a particular component
may be referred to using several different or overlapping terms.
What may be described herein as being a single part may include and
be referenced in another context as consisting of multiple
components. Alternatively, what may be described herein as
including multiple components may be referred to elsewhere as a
single part.
[0017] In addition, several descriptive terms may be used regularly
herein, and it should prove helpful to define these terms at the
onset of this section. These terms and their definitions, unless
stated otherwise, are as follows. As used herein, "downstream" and
"upstream" are terms that indicate a direction relative to the flow
of a fluid, such as the working fluid through the fuel. The term
"downstream" corresponds to the direction of flow of the fluid, and
the term "upstream" refers to the direction opposite to the flow.
The terms "forward" and "aft," without any further specificity,
refer to directions, with "forward" referring to the front or fluid
receiving end of the fuel nozzle, and "aft" referring to the
rearward or discharge end of the fuel nozzle. It is often required
to describe parts that are at differing radial positions with
regard to a centerline or center axis. The term "radial" refers to
movement or position perpendicular to an axis. In cases such as
this, if a first component resides closer to the axis than a second
component, it will be stated herein that the first component is
"radially inward" or "inboard" of the second component. If, on the
other hand, the first component resides further from the axis than
the second component, it may be stated herein that the first
component is "radially outward" or "outboard" of the second
component. The term "axial" refers to movement or position parallel
to the centerline or axis. Finally, the term "circumferential"
refers to movement or position around the centerline or axis. It
will be appreciated that such terms may be applied in relation to
the centerline of the fuel nozzle.
[0018] As indicated above, the disclosure provides an object
including suspension elements for positioning annular bodies
relative to one another, e.g., concentrically. A method for
manufacturing a metallic object is also described. In one example,
the object may take the form of fuel nozzle such as those used for
gas turbines, and may be formed using additive manufacturing.
[0019] To illustrate an example of an additive manufacturing
process, FIG. 1 shows a schematic/block view of an illustrative
computerized additive manufacturing (AM) system 100 for generating
an object 102. In this example, system 100 is arranged for DMLM, a
metal powder additive manufacturing process. It is understood that
the general teachings of the disclosure are equally applicable to
other forms of additive manufacturing. Object 102 is illustrated as
a fuel nozzle 103 including, as will be described, a number of
annular bodies 150A-D (FIG. 3); however, it is understood that the
additive manufacturing process can be readily adapted to
manufacture any object including spaced, annular bodies. AM system
100 generally includes a computerized AM control system 104 and an
AM printer 106. AM system 100, as will be described, executes code
120 that includes a set of computer-executable instructions
defining object 102 to physically generate the object using AM
printer 106. Each AM process may use different raw materials in the
form of, for example, fine-grain metal powder, a stock of which may
be held in a chamber 110 of AM printer 106. In the instant case,
object 102 may be made of metal or a metal alloy. As illustrated,
an applicator 112 may create a thin layer of raw material 114
spread out as the blank canvas from which each successive slice of
the final object will be created. In the example shown, a laser or
electron beam 116 fuses particles for each slice, as defined by
code 120. Various parts of AM printer 106 may move to accommodate
the addition of each new layer, e.g., a build platform 118 may
lower and/or chamber 110 and/or applicator 112 may rise after each
layer.
[0020] AM control system 104 is shown implemented on computer 130
as computer program code. To this extent, computer 130 is shown
including a memory 132, a processor 134, an input/output (I/O)
interface 136, and a bus 138. Further, computer 130 is shown in
communication with an external I/O device/resource 140 and a
storage system 142. In general, processor 134 executes computer
program code, such as AM control system 104, that is stored in
memory 132 and/or storage system 142 under instructions from code
120 representative of object 102. While executing computer program
code, processor 134 can read and/or write data to/from memory 132,
storage system 142, I/O device 140 and/or AM printer 106. Bus 138
provides a communication link between each of the objects in
computer 130, and I/O device 140 can comprise any device that
enables a user to interact with computer 130 (e.g., keyboard,
pointing device, display, etc.). Computer 130 is only
representative of various possible combinations of hardware and
software. For example, processor 134 may comprise a single
processing unit, or be distributed across one or more processing
units in one or more locations, e.g., on a client and server.
Similarly, memory 132 and/or storage system 142 may reside at one
or more physical locations. Memory 132 and/or storage system 142
can comprise any combination of various types of non-transitory
computer readable storage medium including magnetic media, optical
media, random access memory (RAM), read only memory (ROM), etc.
Computer 130 can comprise any type of computing device such as a
network server, a desktop computer, a laptop, a handheld device, a
mobile phone, a pager, a personal data assistant, etc.
[0021] Additive manufacturing processes begin with a non-transitory
computer readable storage medium (e.g., memory 132, storage system
142, etc.) storing code 120 representative of object 102. As noted,
code 120 includes a set of computer-executable instructions
defining object 102 that can be used to physically generate the
object, upon execution of the code by system 100. For example, code
120 may include a precisely defined 3D model of object 102 and can
be generated from any of a large variety of well-known computer
aided design (CAD) software systems such as AutoCAD.RTM.,
TurboCAD.RTM., DesignCAD 3D Max, etc. In this regard, code 120 can
take any now known or later developed file format. For example,
code 120 may be in the Standard Tessellation Language (STL) which
was created for stereolithography CAD programs of 3D Systems, or an
additive manufacturing file (AMF), which is an American Society of
Mechanical Engineers (ASME) standard that is an extensible
markup-language (XML) based format designed to allow any CAD
software to describe the shape and composition of any
three-dimensional object to be fabricated on any AM printer. Code
120 may be translated between different formats, converted into a
set of data signals and transmitted, received as a set of data
signals and converted to code, stored, etc., as necessary. Code 120
may be an input to system 100 and may come from a part designer, an
intellectual property (IP) provider, a design company, the operator
or owner of system 100, or from other sources. In any event, AM
control system 104 executes code 120, dividing object 102 into a
series of thin slices that it assembles using AM printer 106 in
successive layers of powder. In the DMLM example, each layer is
melted or sintered to the exact geometry defined by code 120 and
fused to the preceding layer. Subsequently, object 102 may be
exposed to any variety of finishing processes, e.g., minor
machining, sealing, polishing, assembly to another part, etc.
[0022] FIGS. 2-3 show object 102 including annular bodies 150A,
150B (FIG. 3) capable of employing a plurality of suspension
elements 160 (FIG. 3) according to the teachings of the disclosure.
FIG. 2 shows a perspective view, and FIG. 3 shows a cross-sectional
view of object 102 along line 3-3 in FIG. 2. Object 102 is
illustrated in the form of fuel nozzle 103. It is emphasized that
object 102 in the form of fuel nozzle 103 is merely illustrative of
an object including annular bodies 150 requiring a plurality of
suspension elements 160, and the teachings of the disclosure can be
applied to any object similarly structured. Object 102 (fuel nozzle
103) can be manufactured using additive manufacturing such as a
metal power additive manufacturing system 100 (FIG. 1) or other
additive manufacturing system, depending on material used.
[0023] With reference to FIGS. 3-6, details of embodiments of
object 102 will be described. FIG. 4 shows an enlarged
cross-sectional view, FIG. 5 shows a perspective view and FIG. 6
shows an end view of object 102 (FIGS. 5 and 6 from a proximal end
of fuel nozzle 103). Object 102 may include an annular outer body
150A having an interior surface 162, and an annular inner body 150B
disposed inside annular outer body 150A. Inner body 150B has an
exterior surface 164 defining an annular passage 154A with interior
surface 162 of annular outer body 150A. Where object 102 is a fuel
nozzle 103, it may also include additional annular bodies 150C, D
(4 total shown, 150A-D) that extend to deliver their respective
fluids, e.g., air or fuel, to or near an end 152 (FIG. 2) of fuel
nozzle 103. Generally, each annular body 150B-D, including annular
outer body 150A, extends parallel to a centerline axis C, i.e.,
with some variations. Annular bodies 150B-D create concentric or
near concentric annular passages 154B-D for fuel and air. In the
example shown, annular inner body 150B may include an outer,
combustible fuel carrying element 166 (FIG. 4) of fuel nozzle 103,
i.e., an outer element of the parts of fuel nozzle 103 that carry
fuel or air for combustion outside of fuel nozzle 103. Here,
annular outer body 150A may take the form of a heat shield 168 for
the rest of fuel nozzle 103. In this setting, a space between
interior surface 162 of annular outer body 150A and exterior
surface 164 of annular inner body 150B provides an annular passage
154A for carrying a coolant 170, e.g., air, to cool fuel nozzle
103. Coolant 170 may not be used in the combustion process
occurring near end 152 (FIG. 2).
[0024] In accordance with embodiment of the disclosure, a plurality
of suspension elements 160 connect interior surface 162 of annular
outer body 150A to exterior surface 164 of annular inner body 150B.
Each suspension element 160 is configured to substantially rigidly
locate a position of annular outer body 150A relative to annular
inner body 150B in axial (along centerline C) and lateral
(circumferentially about centerline C) directions while permitting
controlled deflection in a radial direction (perpendicular to
centerline C). To this end, as shown in FIGS. 5 and 6, each
suspension element 160 may include a first end 180 coupled to
annular inner body 150B and a circumferentially spaced, second end
182 coupled to annular outer body 150A. As shown in FIG. 4, each
suspension element 160 extends a distance D parallel to centerline
axis C to create a structure capable of resisting axial and lateral
movement. Further, as shown in FIGS. 5 and 6, first end 180 may
couple to annular inner body 150B at a first angle .alpha.1 between
85.degree. and 95.degree. (e.g., 90.degree.), and second end 182
couples to annular outer body 150A at a second angle .alpha.2
between 85.degree. and 95.degree. (e.g., 90.degree.). In this
fashion, each suspension element 160 may have an S-shape viewed in
the direction of the centerline axis C (see FIG. 6). Any number of
suspension elements 160 deemed necessary to provide the desired,
limited movement may be employed. In FIGS. 5 and 6, seven (7)
elements 160 are employed.
[0025] In embodiments of the disclosure, suspension elements 160
may be circumferentially spaced within annular passage 154A. That
is, plurality of suspension elements 160 may be circumferentially
spaced between interior surface 162 of annular outer body 150A and
exterior surface 164 of annular inner body 150B. In this fashion,
suspension elements 160 provide even absorption of stresses. It is
understood that elements 160 may be unevenly spaced, e.g., if other
mounting structure couples to annular outer body 150A, to provide
an imbalanced suspension capable of addressing an imbalanced
loading. In one embodiment, first end 180 of each respective
suspension element 160 may be within 5.degree. (angle .beta.) of a
circumferentially spaced, second end 182 of an adjacent suspension
element 162 as measured relative to centerline C. The
circumferential arc (CA) (FIG. 6), i.e., the amount each element
160 extends arcuately about centerline C, may vary depending on the
number of elements 160 employed and the desired spacing, if any,
between adjacent ends 180, 182 of adjacent suspension elements
160.
[0026] In order to reduce a pressure drop of coolant 170 within
annular passage 154A, as shown best in FIGS. 3, 4 and 5, each
suspension element 160 has an at least partially tear-shaped
cross-section. In one embodiment, the tear-shape may be
airfoil-shaped. As shown in a cross-section of a suspension element
160 in FIG. 7, the at least partially airfoil-shape can take the
form of any desired airfoil such as but not limited to those
promulgated by the National Advisory Committee for Aeronautics
(NACA). The tear-shaped cross-section may include a leading edge
184 facing a direction of flow of coolant 170 (See FIG. 4).
[0027] A fuel nozzle 103 in accordance with embodiments of the
disclosure may include annular outer heat shield 150A having
interior surface 162. Annular inner body 150B may be disposed
inside outer heat shield 150A. Inner body 150B has an interior 154B
for delivering a combustion material, e.g., fuel and/or air, and
exterior surface 164 defining an annular passage 154A with interior
surface 162 of outer heat shield 150A. Plurality of suspension
elements 160 connect interior surface 162 of outer heat shield 150A
to exterior surface 164 of inner body 150B. Each suspension element
160 is configured to substantially rigidly locate a position of
outer heat shield 150A relative to inner body 150B in axial and
lateral directions while permitting controlled deflection in a
radial direction. As noted, each suspension element 160 may include
an at least partially tear-shaped cross-section.
[0028] As noted, object 102 and fuel nozzle 103 may be formed using
the AM processes described herein, providing a one-piece
construction that is tolerant to thermally induced radial growth
and relatively large axial forces, but also provides a low pressure
drop for coolant. The teachings of the disclosure are applicable to
any situation in which annular bodies need to be positioned within
one another, and limited movement caused by, for example, thermal
stress, is required.
[0029] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
"Optional" or "optionally" means that the subsequently described
event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0030] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about," "approximately"
and "substantially," are not to be limited to the precise value
specified. In at least some instances, the approximating language
may correspond to the precision of an instrument for measuring the
value. Here and throughout the specification and claims, range
limitations may be combined and/or interchanged, such ranges are
identified and include all the sub-ranges contained therein unless
context or language indicates otherwise. "Approximately" as applied
to a particular value of a range applies to both values, and unless
otherwise dependent on the precision of the instrument measuring
the value, may indicate +/-10% of the stated value(s).
[0031] The corresponding structures, materials, acts, and
equivalents of all means or step plus function elements in the
claims below are intended to include any structure, material, or
act for performing the function in combination with other claimed
elements as specifically claimed. The description of the present
disclosure has been presented for purposes of illustration and
description, but is not intended to be exhaustive or limited to the
disclosure in the form disclosed. Many modifications and variations
will be apparent to those of ordinary skill in the art without
departing from the scope and spirit of the disclosure. The
embodiment was chosen and described in order to best explain the
principles of the disclosure and the practical application, and to
enable others of ordinary skill in the art to understand the
disclosure for various embodiments with various modifications as
are suited to the particular use contemplated.
* * * * *