U.S. patent application number 13/557806 was filed with the patent office on 2013-05-02 for urea solution pump structure.
This patent application is currently assigned to Hyundai Motor Company. The applicant listed for this patent is Pil Seon Choi, Junhyuck Jang, Jongman Lee, Jong-Sang Noh, Dong Myoung Ryoo, Buyeol Ryu. Invention is credited to Pil Seon Choi, Junhyuck Jang, Jongman Lee, Jong-Sang Noh, Dong Myoung Ryoo, Buyeol Ryu.
Application Number | 20130108484 13/557806 |
Document ID | / |
Family ID | 48084473 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130108484 |
Kind Code |
A1 |
Ryoo; Dong Myoung ; et
al. |
May 2, 2013 |
UREA SOLUTION PUMP STRUCTURE
Abstract
A urea solution pump structure may include a housing portion
connected to an external connector and covering an upper portion of
the pump structure, a motor portion disposed at a lower portion of
the housing portion and including a rotor and a stator, a case
portion receiving the motor portion therein, and a pump portion
disposed at a lower portion of the case portion and fluid-isolated
from the motor portion, wherein the pump portion may be formed with
an inlet and an outlet for a fluid, wherein a hollow cover may be
provided at a lower portion of the case portion for separating the
pump portion and the motor portion, and an oil seal unit may be
mounted at a lower portion of the hollow cover for sealing a
rotating shaft of the rotor which penetrates through the hollow
cover.
Inventors: |
Ryoo; Dong Myoung;
(Yongin-si, KR) ; Ryu; Buyeol; (Hwaseong-si,
KR) ; Choi; Pil Seon; (Anyang-si, KR) ; Noh;
Jong-Sang; (Ulsan, KR) ; Lee; Jongman;
(Yangsan-si, KR) ; Jang; Junhyuck; (Pohang-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ryoo; Dong Myoung
Ryu; Buyeol
Choi; Pil Seon
Noh; Jong-Sang
Lee; Jongman
Jang; Junhyuck |
Yongin-si
Hwaseong-si
Anyang-si
Ulsan
Yangsan-si
Pohang-si |
|
KR
KR
KR
KR
KR
KR |
|
|
Assignee: |
Hyundai Motor Company
Seoul
KR
Dong Hee Industrial Co., Ltd.
Ulsan
KR
Kia Motors Corporation
Seoul
KR
|
Family ID: |
48084473 |
Appl. No.: |
13/557806 |
Filed: |
July 25, 2012 |
Current U.S.
Class: |
417/410.1 |
Current CPC
Class: |
F04C 11/008 20130101;
F01C 21/104 20130101; F04C 15/0038 20130101; F01C 19/005 20130101;
F04C 2210/1083 20130101; F01C 21/007 20130101; F04C 2/18
20130101 |
Class at
Publication: |
417/410.1 |
International
Class: |
F04B 35/04 20060101
F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2011 |
KR |
10-2011-0113265 |
Claims
1. A urea solution pump structure, comprising: a housing portion
connected to an external connector and covering an upper portion of
the pump structure; a motor portion disposed at a lower portion of
the housing portion and including a rotor and a stator; a case
portion receiving the motor portion therein; and a pump portion
disposed at a lower portion of the case portion and fluid-isolated
from the motor portion, wherein the pump portion is formed with an
inlet and an outlet for a fluid, wherein a hollow cover is provided
at a lower portion of the case portion for separating the pump
portion and the motor portion, and an oil seal unit is mounted at a
lower portion of the hollow cover for sealing a rotating shaft of
the rotor which penetrates through the hollow cover.
2. The urea solution pump structure of claim 1, wherein the oil
seal unit includes: a fixed element mounted under the hollow cover
and enclosing the rotating shaft of the motor portion; a rotating
element fixed to the rotating shaft to rotate with the rotating
shaft; a pressing element disposed under the rotating element and
elastically biased toward the rotating element.
3. The urea solution pump structure of claim 2, wherein a damping
space is formed between an interior circumference of the pump
portion and the rotating element of the oil seal unit.
4. The urea solution pump structure of claim 1, wherein the oil
seal unit is a mechanical seal.
5. The urea solution pump structure of claim 4, wherein a damping
space is formed between an interior circumference of the pump
portion and an exterior surface of the mechanical seal.
6. The urea solution pump structure of claim 5, wherein the pump
portion includes a gear box being a main body of the pump portion,
a gear pump mounted at a groove formed on a lower portion of the
gear box, and a lower panel covering a lower surface of the gear
box and formed with the inlet and the outlet, and the damping space
is formed between an interior circumference of the gear box and the
mechanical seal.
7. The urea solution pump structure of claim 6, wherein a filler is
provided in the damping space for absorbing expansion of a urea
solution.
8. The urea solution pump structure of claim 6, wherein the filler
is compressible.
9. The urea solution pump structure of claim 7, wherein a drain
hole is formed or a relief valve is mounted at a lower surface of
the damping space in the gear box close to the inlet for preventing
overpressure of the fluid.
10. The urea solution pump structure of claim 9, wherein the drain
hole or the relief valve is formed between the damping space and
the inlet and connected to the inlet.
11. The urea solution pump structure of claim 1, wherein a bearing
is provided at an upper portion of the case portion for supporting
the rotation of the rotating shaft.
12. The urea solution pump structure of claim 5, wherein the pump
portion includes a main body portion which forms the damping space,
a gear pump portion which is engaged at a lower portion of the main
body portion and of which a gear pump is provided with therein, and
a lower panel covering a lower surface of the gear pump portion and
connecting to the gear pump portion being formed with the inlet and
the outlet.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2011-0113265 filed in the Korean Intellectual
Property Office on Nov. 2, 2011, the entire contents of which is
incorporated herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a urea solution pump
structure. More particularly, the present invention relates to a
urea solution pump structure used in a urea-SCR system in which a
motor portion can be protected by effectively preventing a leakage
of urea.
[0004] 2. Description of Related Art
[0005] A vehicle can be classified by the type of the vehicle such
as a sedan, bus, and truck. On the other hand, the vehicle can be
classified by the type of fuel such as a gasoline vehicle using
gasoline as fuel, a diesel vehicle using diesel as fuel, and a
liquefied petroleum gas (LPG) vehicle even if the type of vehicle
is the same.
[0006] It is more difficult to eliminate NOx in a diesel vehicle
than a gasoline vehicle because diesel is burned in an excess
oxygen state such as a lean burn state, and as a result, a lot of
NOx is generated. Therefore, a urea selective catalytic reduction
(urea-SCR) system is being developed as a main technology for
eliminating NOx.
[0007] The urea-SCR system supplies urea (NH.sub.2--CO--NH.sub.2)
as a type of aqueous solution, the urea solution is pyrolyzed into
ammonia (NH.sub.3) and isocyanic acid (HNCO) by a high temperature
exhaust gas, and the isocyanic acid (HNCO) is hydrolyzed into
ammonia and carbon dioxide by water of the exhaust gas. The ammonia
generated by the above-mentioned method is used as a catalyst for
changing NOx into N.sub.2+O.sub.2.
[0008] The urea-SCR system generally has an injector for injecting
urea, a pump for supplying a urea solution in the urea tank to the
injector, and a CPU for controlling an injecting pressure and an
injecting time.
[0009] It is difficult to use a gasoline fuel pump or a diesel fuel
pump used for a vehicle engine as a pump for supplying urea.
Because the urea solution is a strong alkaline material (Ph 9-11),
suit corrodes almost every metal except an SUS material.
[0010] As shown in FIG. 1, a conventional brushless direct current
motor within a fuel pump (BLDC fuel pump) has a structure in which
a fuel is pressurized by the pump rotation and the pressurized fuel
is discharged from an upper end of a motor portion after passing
through the motor portion.
[0011] Therefore, if the conventional fuel pump is used for a urea
solution pump, a motor of the pump formed with copper or steel may
be seriously damaged by the highly corrosive urea solution. An
actual test showed that the conventional pump malfunctioned because
of corrosion caused by the urea solution after 4 to 6 hours of
operation.
[0012] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
general background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art already known to a person skilled in the
art.
BRIEF SUMMARY
[0013] Various aspects of the present invention are directed to
providing a urea solution pump structure having advantages of
preventing corrosion caused by urea solution leakage, reducing
manufacturing cost, and reducing noise.
[0014] In an aspect of the present invention, a urea solution pump
structure may include a housing portion connected to an external
connector and covering an upper portion of the pump structure, a
motor portion disposed at a lower portion of the housing portion
and including a rotor and a stator, a case portion receiving the
motor portion therein, and a pump portion disposed at a lower
portion of the case portion and fluid-isolated from the motor
portion, wherein the pump portion is formed with an inlet and an
outlet for a fluid, wherein a hollow cover is provided at a lower
portion of the case portion for separating the pump portion and the
motor portion, and an oil seal unit is mounted at a lower portion
of the hollow cover for sealing a rotating shaft of the rotor which
penetrates through the hollow cover.
[0015] The oil seal unit may include a fixed element mounted under
the hollow cover and enclosing the rotating shaft of the motor
portion, a rotating element fixed to the rotating shaft to rotate
with the rotating shaft, a pressing element disposed under the
rotating element and elastically biased toward the rotating
element.
[0016] A damping space is formed between an interior circumference
of the pump portion and the rotating element of the oil seal
unit.
[0017] The oil seal unit is a mechanical seal.
[0018] A damping space is formed between an interior circumference
of the pump portion and an exterior surface of the mechanical
seal.
[0019] The pump portion may include a gear box being a main body of
the pump portion, a gear pump mounted at a groove formed on a lower
portion of the gear box, and a lower panel covering a lower surface
of the gear box and formed with the inlet and the outlet, and the
damping space is formed between an interior circumference of the
gear box and the mechanical seal.
[0020] A filler is provided in the damping space for absorbing
expansion of a urea solution.
[0021] The filler is compressible.
[0022] A drain hole is formed or a relief valve is mounted at a
lower surface of the damping space in the gear box close to the
inlet for preventing overpressure of the fluid.
[0023] The drain hole or the relief valve is formed between the
damping space and the inlet and connected to the inlet.
[0024] A bearing is provided at an upper portion of the case
portion for supporting the rotation of the rotating shaft.
[0025] The pump portion may include a main body portion which forms
the damping space, a gear pump portion which is engaged at a lower
portion of the main body portion and of which a gear pump is
provided with therein, and a lower panel covering a lower surface
of the gear pump portion and connecting to the gear pump portion
being formed with the inlet and the outlet.
[0026] The urea solution pump structure according an exemplary
embodiment of the present invention may reliably protect the motor
portion from the urea solution by separating the motor portion from
the pump portion and sealing the joint part of the motor portion
and the pump portion by a mechanical seal.
[0027] Further, the present invention may prevent damage to the
pump portion by forming a damping space between the mechanical seal
and the pump portion.
[0028] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a perspective view of a urea solution pump
structure according to the conventional art.
[0030] FIG. 2 is an exploded perspective view of a urea solution
pump structure according to an exemplary embodiment of the present
invention.
[0031] FIG. 3 is a combined cross-sectional view of a urea solution
pump structure according to an exemplary embodiment of the present
invention.
[0032] FIG. 4 is a perspective view of an essential part of a urea
solution pump structure according to an exemplary embodiment of the
present invention.
[0033] FIG. 5 is a perspective view of an inner part of a urea pump
structure according to an exemplary embodiment of the present
invention.
[0034] FIG. 6 is a perspective view of an inner part of a urea pump
structure according to another exemplary embodiment of the present
invention.
[0035] FIG. 7 is a cross-sectional view of an inner part of a urea
pump structure according to another exemplary embodiment of the
present invention.
[0036] FIG. 8 is a perspective view of an inner part of a urea pump
structure according to another exemplary embodiment of the present
invention.
[0037] FIG. 9 is an exploded perspective view of a housing portion
according to an exemplary embodiment of the present invention.
[0038] FIG. 10 is an exploded perspective view of a stator of a
motor portion according to an exemplary embodiment of the present
invention.
[0039] FIG. 11 is an exploded perspective view of a rotor of a
motor portion according to an exemplary embodiment of the present
invention.
[0040] FIG. 12 is an exploded perspective view of a case portion
according to an exemplary embodiment of the present invention.
[0041] FIG. 13 is an exploded perspective view of a pump portion
according to an exemplary embodiment of the present invention.
[0042] FIG. 14 is a cross-sectional view of a pump portion
according to another exemplary embodiment of the present
invention.
[0043] It should be understood that the appended drawings are not
necessarily to scale, presenting a somewhat simplified
representation of various features illustrative of the basic
principles of the invention. The specific design features of the
present invention as disclosed herein, including, for example,
specific dimensions, orientations, locations, and shapes will be
determined in part by the particular intended application and use
environment.
[0044] In the figures, reference numbers refer to the same or
equivalent parts of the present invention throughout the several
figures of the drawing.
DETAILED DESCRIPTION
[0045] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that the present description is
not intended to limit the invention(s) to those exemplary
embodiments. On the contrary, the invention(s) is/are intended to
cover not only the exemplary embodiments, but also various
alternatives, modifications, equivalents and other embodiments,
which may be included within the spirit and scope of the invention
as defined by the appended claims.
[0046] An exemplary embodiment of the present invention will
hereinafter be described in detail with reference to the
accompanying drawings.
[0047] FIG. 2 is an exploded perspective view of a urea solution
pump structure 10 according to an exemplary embodiment of the
present invention, FIG. 3 is a combined cross-sectional view of a
urea solution pump structure 10 according to an exemplary
embodiment of the present invention, FIG. 4 is a perspective view
of an essential part of a urea solution pump structure 10 according
to an exemplary embodiment of the present invention, and FIG. 5 is
a perspective view of an inner part of a urea pump structure 10
according to an exemplary embodiment of the present invention.
[0048] As shown in FIG. 2 to FIG. 5, the urea solution pump
structure 10 according to an exemplary embodiment of the present
invention may include a housing portion 100 connected to an
external connector and covering the upper portion of the pump
structure, a motor portion 200 disposed at a lower portion of the
housing portion and including a rotor 220 and a stator 210, a case
portion 300 receiving the motor portion 200 therein, and a pump
portion 400 disposed at a lower portion of the case portion 300 and
formed with an inlet 441 and an outlet 442 for a fluid.
[0049] A hollow cover 310 is provided at a lower portion of the
case portion 300 for separating the pump portion 400 and the motor
portion 200, and an oil seal unit 320 is mounted at a lower portion
of the hollow cover 310 for sealing a rotating shaft 221 of the
rotor 220 which penetrates through the hollow cover 310.
[0050] The present invention protects the motor portion from
corrosion by providing the hollow cover 310 and sealing the
rotating shaft 221 of the rotor 220.
[0051] Further, the urea pump structure according to an exemplary
embodiment of the present invention protects the motor portion 200
from the urea solution by separating the motor portion 200 and the
pump portion 400, and forming both the inlet 441 and the outlet 442
at the pump portion 400 for making the urea solution pass through
the inlet 441 and the outlet 442.
[0052] The housing portion 100 is an upper cover of the urea
solution pump structure 10 and is connected to an external
connector.
[0053] As shown in FIG. 9, the housing portion 100 may include a
housing 110 forming a main body of the housing portion 100 and
receiving the external connector therein, a printed circuit board
(PCB) 120 mounted in the housing 110 and switching power, a first
ring seal 130 for preventing leakage through the housing portion
100, and a terminal 140 applying an electric current and inserted
into the external connector.
[0054] The housing 110 may be made with a PBT+GF30% material which
has excellent insulation resistance and chemical resistance, the
PCB 120 may be made with an FR-4 material which has heat
resistance, moisture resistance, and high safety by layering glass
fibers with an epoxy resin, the first ring seal 130 may be made
with an H-NBR material having heat resistance, ozone resistance,
and oil and fuel resistance, and the terminal 140 may be made with
brass (C2680) having corrosion resistance, machinability, and easy
plating ability.
[0055] The motor portion 200 may be composed of the stator 210 and
the rotor 220.
[0056] The stator 210, as shown in FIG. 10, may include upper and
lower insulators 211 and 214 for insulating, a magnet wire 213 for
generating a magnetic field, and a stator core 212 with the magnet
wire 213 wound around it as a laminated core.
[0057] The upper insulator 211 and the lower insulator 214 may be
made with a PBT+GF30% material which has excellent insulation
resistance and chemical resistance, the stator core 212 may be made
with an S18 material having excellent relative permeability and
that is generally used in a motor, and the magnet wire 213 may be
made with an AIW material having ozone resistance and chemical
resistance.
[0058] The rotor 220, as shown in FIG. 11, may include the rotating
shaft 221, a magnet 222 disposed at the outside of the rotating
shaft 221, a magnetic detector 223 for measuring a position of a
hall sensor, and a push nut 224 for fixing the magnetic detector
223.
[0059] The rotating shaft 221 may be made with an SUS304 material
which has corrosion resistance, machinability, and easy plating
ability, the magnet 222 may be an ND-bonded magnet which has
corrosion resistance and high safety, the magnetic detector 223 may
be made with a plastic magnet material having machinability and
shock resistance, and the push nut 224 may be made with stainless
steel used for a spring.
[0060] The case portion 300, as shown in FIG. 12, may include the
hollow cover 310 provided at a lower portion of the case portion
300, the oil seal unit 320 mounted at a lower portion of the hollow
cover 310 for preventing leakage of a fluid, and a bearing 330
provided at an upper portion of the case portion 300 for supporting
the rotation of the rotating shaft 221.
[0061] The hollow cover 310, as shown in FIG. 6 and FIG. 7,
separates the pump portion 400 and the motor portion 200 by being
mounted at the upper position of the pump portion 400. A second
ring seal 340 may be adapted at the joint part of the hollow cover
310 and the pump portion 400 for preventing leakage.
[0062] In one or a plurality of exemplary embodiments, as shown in
FIG. 6 and FIG. 7, the lower surface of the cover 310 may have a
concave structure, and the oil seal unit 320 may be inserted into
the concave structure of the cover 310.
[0063] The oil seal unit 320 prevents leakage of a urea solution
between the motor portion 200 and the rotating shaft 221 by being
closely formed to the exterior circumference of the rotating shaft
221
[0064] The oil seal unit 320 prevents the urea solution from
flowing into the motor portion 200 from the gap between the motor
portion 200 and the rotating shaft 221 by being closely disposed to
the exterior circumference of the rotating shaft 221.
[0065] In one or a plurality of exemplary embodiments, the oil seal
unit 320 may be a mechanical seal.
[0066] A mechanical seal is generally used to prevent leakage of a
fluid from a rotating shaft at a high temperature and high
pressure. In general, the mechanical seal has a rotating element
for rotating with a shaft and a fixed element fixed at a body, and
the rotating element and the fixing element are closely formed with
each other so as to move with respect to each other while
maintaining an airtight and watertight seal at the contact
surface.
[0067] In one or a plurality of exemplary embodiments, as shown in
FIG. 6 and FIG. 7, the mechanical seal 320 may include a rotating
element 321 rotating with the rotating shaft 221 of the motor
portion 200, and a fixed element 322 fixed at the hollow cover 310.
A pressing element 323 such as a coil spring may be provided at the
back of the rotating element 321 so as to contact the rotating
element 321 and the fixed element 322 evenly by pressing the
rotating element 321 toward the fixed element 322, such that
leakage between the rotating element 321 and the fixing element 322
may be effectively prevented by the force of the pressing element
323 and a force of hydraulic fluid in the mechanical seal.
[0068] As shown in FIG. 3 and FIG. 5, the bearing may be provided
at the upper portion of the case portion for supporting the
rotation of the rotating shaft. As shown in FIG. 3, the magnetic
detector 223 of the motor portion 200 may be disposed at the upper
portion of the bearing 330.
[0069] In one or a plurality of exemplary embodiments, as shown in
FIG. 13, the pump portion 400 may include a gear box 420 being a
main body of the pump portion 400, a gear pump 430 mounted at a
groove formed on a lower portion of the gear box 420, and a lower
panel 440 covering a lower surface of the gear box 420 and formed
with the inlet 441 and the outlet 442.
[0070] The motor portion 200 is protected from corrosion by the
urea solution since both the inlet 441 and the outlet 442 are
formed at the lower panel 440 of the pump portion 400 such that the
urea solution cannot flow into the upper side of the pump portion
400.
[0071] A damping space 410 may be formed between the interior
circumference of the gear box 420 and the mechanical seal 320.
[0072] If the urea solution leaks from a gap between the rotating
shaft 221 and the pump portion 400 following the arrow direction
shown in FIG. 3, the damping space 410 receives the urea solution
having leaked from the gap. The urea solution having leaked from
the gap has no place to be received if the damping space 410 is not
formed between the interior circumference of the gear box 420 and
the mechanical seal 320 such that the pump portion 400 may be
damaged by freezing distension of the urea solution when the
temperature drops. Therefore the damping space 410 plays a role in
preventing damage to the pump portion 400.
[0073] As shown in FIG. 6, a compressible filler 411 such as
silicon may be spread or attached in the damping space 410 for
absorbing the expansion of the urea solution. If the filler 411 is
provided in the damping space 410, the pump portion 400 may be
protected by the filler since the filler 411 makes room for
absorbing the freezing distension of the urea solution even when
the urea solution is filled in the damping space 410.
[0074] A drain hole 421 may be formed or a relief valve may be
mounted at a lower surface of the gear box 420 of the side where
the inlet 441 is located for preventing overpressure caused by
pumping the urea solution. As shown in FIG. 8, if the urea solution
is excessively pressurized, the urea solution is discharged toward
the B direction by passing through the drain hole 421 or a relief
valve. Therefore, the pump portion 400 is protected from an
excessively high pressure by the drain hole 421 or the relief
valve.
[0075] As shown in FIG. 13, the gear pump 430 may be mounted in a
groove which is formed at the bottom of the gear box 420. The gear
pump 430 may be a pump that inversely discharges a fluid by counter
rotation. An internal gear pump, an external gear pump, a roller
cell pump, or a geroter pump may be used as the gear pump 430
according to a situation.
[0076] As shown in FIG. 5, a third ring seal 450 and a fourth ring
seal 451 may be provided between the gear box 420 and the lower
panel 440 for preventing leakage of fluid pumped by the gear pump
430.
[0077] FIG. 14 is a cross-sectional view of the pump portion
according to another exemplary embodiment of the present
invention.
[0078] As shown in FIG. 14, the pump portion 400 a according to
another exemplary embodiment of the present invention includes a
main body portion 460 which forms the damping space 410, a gear
pump portion 470 which is engaged at a lower portion of the main
body portion 460 and of which a gear pump 430 is provided with
therein, and a lower panel 440 covering a lower surface of the gear
pump portion 470 and connecting to the gear pump portion 470 being
formed with the inlet 441 and the outlet 442.
[0079] The main body portion 460 forms the damping space 410 and
the mechanical seal 320 is provided with therein.
[0080] The gear pump portion 470 of which the gear pump 430 is
provided with therein is separated from the main body portion 460,
as a result a size of the gear pump portion 470 can be easily
changed according to a type or a size of the gear pump 430.
[0081] As shown in FIG. 14, the gear pump portion 470 may be formed
in shape of a plate of which the gear pump 430 is provided with
therein. As a result the pump portion 400 is divided into three
layers and it becomes easy to change a size or a gap of the pump
portion 400.
[0082] The urea solution pump structure 10 according the exemplary
embodiment of the present invention may reliably protect the motor
portion from the urea solution by separating the motor portion 200
from the pump portion 400 and sealing the joint part of the motor
portion 200 and the pump portion 400 by the oil seal unit 320 such
as a mechanical seal.
[0083] Further, the present invention may prevent damage to the
pump portion 400 by forming the damping space 410 between the
mechanical seal 320 and the pump portion 400.
[0084] While this invention has been described in connection with
what is presently considered to be practical exemplary embodiments,
it is to be understood that the invention is not limited to the
disclosed embodiments, but, on the contrary, is intended to cover
various modifications and equivalent arrangements included within
the spirit and scope of the appended claims.
[0085] For convenience in explanation and accurate definition in
the appended claims, the terms "upper", "lower", "inner" and
"outer" are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0086] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described in order to explain certain principles of
the invention and their practical application, to thereby enable
others skilled in the art to make and utilize various exemplary
embodiments of the present invention, as well as various
alternatives and modifications thereof. It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *