U.S. patent application number 15/333797 was filed with the patent office on 2017-02-16 for combination capacitive and resistive obstacle sensor.
The applicant listed for this patent is Magna Closures Inc.. Invention is credited to Liviu Bolbocianu, Allan Corner, Timothy Dezorzi, Thomas Mellary, Anjan Nayani, Alex Porat, Mirko Pribisic, Erik Schattenmann.
Application Number | 20170044813 15/333797 |
Document ID | / |
Family ID | 51538213 |
Filed Date | 2017-02-16 |
United States Patent
Application |
20170044813 |
Kind Code |
A1 |
Pribisic; Mirko ; et
al. |
February 16, 2017 |
COMBINATION CAPACITIVE AND RESISTIVE OBSTACLE SENSOR
Abstract
An obstacle sensor for a closure panel of a vehicle includes an
elongate non-conductive case which encloses a first, second, and
third elongate conductive electrodes. The first and second
electrodes are separated by a portion of the case, with a
capacitance between the first and second electrodes changing when
an obstacle approaches the first electrode. The changed capacitance
of the obstacle sensor provides a proximity indication of the
obstacle to the obstacle sensor. The second and third electrodes
are separated by an air gap formed in the case, with a resistance
between the second and third electrodes changing when the second
and third electrodes come into contact upon compression of the case
by the obstacle. The changed resistance of the obstacle sensor
provides a contact indication of the obstacle with the obstacle
sensor.
Inventors: |
Pribisic; Mirko; (North
York, CA) ; Bolbocianu; Liviu; (North York, CA)
; Porat; Alex; (Thornhill, CA) ; Mellary;
Thomas; (East Gwillimbury, CA) ; Dezorzi;
Timothy; (South Lyon, MI) ; Corner; Allan;
(Aurora, CA) ; Schattenmann; Erik; (Toronto,
CA) ; Nayani; Anjan; (North York, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Magna Closures Inc. |
Newmarket |
|
CA |
|
|
Family ID: |
51538213 |
Appl. No.: |
15/333797 |
Filed: |
October 25, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14766937 |
Aug 10, 2015 |
9477003 |
|
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PCT/IB2014/001117 |
Mar 14, 2014 |
|
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15333797 |
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61791472 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01V 3/08 20130101; H03K
17/9645 20130101; G01D 5/24 20130101; H03K 2217/96054 20130101;
E05Y 2400/52 20130101; H03K 2217/96078 20130101; E05Y 2400/10
20130101; E05Y 2800/73 20130101; E05F 15/46 20150115; H03K 17/955
20130101; E05Y 2900/532 20130101; E05Y 2400/44 20130101; G01D 5/16
20130101; B60J 5/101 20130101; G01R 27/02 20130101; E05F 15/44
20150115; H03K 17/962 20130101 |
International
Class: |
E05F 15/46 20060101
E05F015/46; H03K 17/96 20060101 H03K017/96; G01D 5/24 20060101
G01D005/24; G01V 3/08 20060101 G01V003/08; G01D 5/16 20060101
G01D005/16 |
Claims
1. An closure system for a motor vehicle comprising: a closure
panel pivotably mounted to a body of the vehicle for movement
between open and closed positions; and an obstacle sensing system
including an obstacle sensor having an elongate non-conductive case
enclosing a first, second, and third elongate conductive
electrodes, said first and second electrodes being separated by a
portion of said case, a capacitance between said first and second
electrodes changing when an obstacle approaches said first
electrode to provide a proximity indication of the obstacle to the
obstacle sensor, and said second and third electrodes being
separated by an air gap formed in the case, a resistance between
said second and third electrodes changing when the second and third
electrodes come into contact upon compression of the case by the
obstacle to provide a contact indication of the obstacle with the
obstacle sensor, wherein said second and third electrodes are
bounded by compressible spring side walls of said case to allow
said second and third electrodes to contact one another when the
obstacle sensor is contacted by the obstacle.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. Ser. No.
14/766,937 filed Aug. 10, 2015, now U.S. Pat. No. 9,477,003 issued
Oct. 25, 2016, which is a National Stage of International
Application No. PCT/IB2014/001117 filed Mar. 14, 2014, which claims
the benefit and priority to U.S. provisional patent application
Ser. No. 61/791,472 filed on Mar. 15, 2013. The entire disclosures
of each of the above applications are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] This invention relates to the field of obstacle sensors, and
more specifically, to a combination capacitive and resistive
obstacle sensor for use in vehicles and other devices.
BACKGROUND
[0003] In motor vehicles such as minivans, sport utility vehicles
and the like, it has become common practice to provide the vehicle
body with a large rear opening. A liftgate (also referred to as a
tailgate) is typically mounted to the vehicle body or chassis with
hinges for pivotal movement about a transversely extending axis
between an open position and a closed position. Typically, the
liftgate may be operated manually or with a power drive mechanism
including a reversible electric motor.
[0004] During power operation of a vehicle liftgate, the liftgate
may unexpectedly encounter an object or obstacle in its path. It is
therefore desirable to cease its powered movement in that event to
prevent damage to the obstacle and/or to the liftgate by pinching
of the obstacle between the liftgate and vehicle body proximate the
liftgate hinges.
[0005] Obstacle sensors are used in such vehicles to prevent the
liftgate from closing if an obstacle (e.g., a person, etc.) is
detected as the liftgate closes. Obstacle sensors come in different
forms, including non-contact or proximity sensors and contact
sensors (e.g., pinch sensors) which rely on physical deformation
caused by contact with an obstacle. Non-contact or proximity
sensors are typically based on capacitance changes while contact
sensors are typically based on resistance changes.
[0006] Non-contact sensors typically include a metal strip or wire
which is embedded in a plastic or rubber strip which is routed
along and adjacent to the periphery of the liftgate. The metal
strip or wire and the chassis of the vehicle collectively form the
two plates of a sensing capacitor. An obstacle placed between these
two plates changes the dielectric constant and thus varies the
amount of charge stored by the sensing capacitor over a given
period of time. The charge stored by the sensing capacitor is
transferred to a reference capacitor in order to detect the
presence of the obstacle.
[0007] Contact sensors are typically applied in the form of a
rubber strip which is routed along and adjacent to the periphery of
the liftgate. The rubber strip embeds two wires which are separated
by an air gap. When the two wires contact one another, the
electrical resistance therebetween drops, and a controller
connected to the two wires monitors the drop in resistance,
detecting an object when the drop exceeds a predetermined
threshold. One problem with such contact sensors, however, is that
they have a limited activation angle typically on the order of
about thirty five degrees. Thus, in the event the pinch force is
applied obliquely rather than head on, the wires may not contact
one another.
[0008] A need therefore exists for an improved obstacle sensor for
use in vehicles and other devices. Accordingly, a solution that
addresses, at least in part, the above and other shortcomings is
desired.
SUMMARY OF THE INVENTION
[0009] According to one aspect of the invention, there is provided
an obstacle sensor, comprising: an elongate non-conductive case
enclosing first, second, and third elongate conductive electrodes;
the first and second electrodes being separated by a portion of the
case, a capacitance between the first and second electrodes
changing when an obstacle approaches the first electrode to provide
a proximity indication; and, the second and third electrodes being
separated by an air gap formed in the case, a resistance between
the second and third electrodes changing when the second and third
electrodes come into contact upon compression of the case by the
obstacle to provide a contact indication.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Features and advantages of the embodiments of the present
invention will become apparent from the following detailed
description, taken in combination with the appended drawings, in
which:
[0011] FIG. 1 is rear perspective view illustrating an obstacle
sensing system for a liftgate of a vehicle in accordance with an
embodiment of an aspect of the invention;
[0012] FIG. 2 is a block diagram illustrating the obstacle sensing
system of FIG. 1 in accordance with an embodiment of an aspect of
the invention;
[0013] FIG. 3 is a cross sectional view illustrating an obstacle
sensor in accordance with an embodiment of an aspect of the
invention;
[0014] FIG. 4 is a wiring diagram illustrating connection of an
obstacle sensor to a controller in accordance with an embodiment of
an aspect of the invention;
[0015] FIG. 5 is a cross sectional view illustrating an obstacle
sensor mounted on a liftgate in accordance with an embodiment of an
aspect of the invention; and,
[0016] FIG. 6 is a flow chart illustrating operations of modules
within an obstacle sensing system for detecting contact with or
proximity of an obstacle, in accordance with an embodiment of an
aspect of the invention.
[0017] It will be noted that throughout the appended drawings, like
features are identified by like reference numerals.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0018] In the following description, details are set forth to
provide an understanding of the invention. In some instances,
certain circuits, structures and techniques have not been described
or shown in detail in order not to obscure the invention.
[0019] FIG. 1 is rear perspective view illustrating an obstacle
sensing system 10 for a liftgate 12 of a vehicle 14 in accordance
with an embodiment of an aspect of the invention. And, FIG. 2 is a
block diagram illustrating the obstacle sensing system 10 of FIG. 1
in accordance with an embodiment of an aspect of the invention. The
obstacle sensing system 10 is shown operatively associated with a
closure panel 12 of a motor vehicle 14. According to one
embodiment, the closure panel is a liftgate 12. It will be
understood by those skilled in the art that the obstacle sensing
system 10 may be used with other closure panels and windows of a
vehicle or other device.
[0020] The liftgate 12 is mounted to a body 16 of the motor vehicle
14 through a pair of hinges 18 to pivot about a transversely
extending pivot axis with respect to a large opening 500 (see FIG.
5) in the rear of the body 16. The liftgate 12 is mounted to
articulate about its hinge axis between a closed position where it
closes the opening 500 and an open position where it uncovers the
opening 500 for free access to the vehicle body interior and
assumes a slightly upwardly angled position above horizontal. The
liftgate 12 is secured in its closed position by a latching
mechanism (not shown). The liftgate 12 is opened and closed by a
drive mechanism 20 with the optional assist of a pair of gas
springs 21 connected between the liftgate 12 and the body 16. The
drive mechanism 20 may be similar to that described in PCT
International Patent Application No. PCT/CA2012/000870, filed Sep.
20, 2012, and incorporated herein by reference. The drive mechanism
20 may be or include a powered strut as described in U.S. Pat. No.
7,938,473, issued May 20, 2011, and incorporated herein by
reference.
[0021] According to one embodiment, the obstacle sensing system 10
includes two obstacle sensors 22, a mounting channel or track 24
for each of the sensors 22, and a controller 26. The pair of
sensors 22 are positioned proximate to laterally opposing sides 28
and 30 of the liftgate 12. Both of the sensors 22 include an upper
end in close proximity to an upper lateral edge 32 of the liftgate
12. The sensors 22 extend downwardly from their upper ends along a
substantial portion of the liftgate 12. The sensors 22 are both
electrically attached to a wire harness 430 adapted to plug into
the controller 26. The controller 26 controls the drive mechanism
20 to open the liftgate 12 in the event it receives an electrical
signal from one or more of the sensors 22.
[0022] According to one embodiment, each of the sensors 22 is
mounted to the liftgate 12 through a mounting track 24. The
mounting tracks 24 may be substantial mirror images of one another.
For this reason, only one of the mounting tracks 24 needs to be
described herein. The mounting track 24 provides a mounting surface
for the sensor 22 which can deflect after the sensor 22 compresses
and sends a control signal to the controller 26. This deflection
allows the controller 26 sufficient time to reverse the drive
mechanism 20 without damaging the obstacle, the liftgate 12 or the
drive mechanism 20. The mounting track 24 also provides a gradually
changing surface to which the sensor 22 may be mounted. According
to one embodiment, the sensors 22 are mounted to the mounting
tracks 24, which are in turn attached to the liftgate 12.
Alternatively, it will be understood that in certain applications
it may be desirable to mount the sensors 22 and their associated
tracks 24 on the body 16 of the vehicle 14 adjacent to the liftgate
12.
[0023] In operation, when the liftgate 12 contacts or approaches an
obstacle proximate to the sensor 22 as it is articulated towards
its closed position, the sensor 22 is activated. The activation of
the sensor 22 is detected by the controller 26. In response, the
controller 26 reverses the drive mechanism 20 to articulate the
liftgate 12 to its open position.
[0024] The drive mechanism 20 is controlled in part by the obstacle
sensing system 10. The obstacle sensing system 10 includes elongate
sensors 22 that help prevent the liftgate 12 from pinching or
crushing an obstacle such a person's finger (not shown) that may be
extending through the opening 500 when the liftgate 12 lowers
towards or nears its closed position. It will be appreciated by
those skilled in the art that the obstacle sensing system 10 may be
applied to any motorized or automated closure panel structure that
moves between an open position and a closed position. For example,
a non-exhaustive list of closure panels includes window panes,
sliding doors, tailgates, sunroofs and the like. For applications
such as window panes or sun roofs, the elongate sensors 22 may be
mounted on the body 16 of the vehicle 14, and for applications such
as powered liftgates and sliding doors the elongate sensor 22 may
be mounted on the closure panel itself, e.g., at the leading edge
of a sliding door or the side edges of a liftgate 12.
[0025] FIG. 3 is a cross sectional view illustrating an obstacle
sensor 22 in accordance with an embodiment of an aspect of the
invention. FIG. 4 is across sectional view illustrating an obstacle
sensor 22 mounted on a liftgate 12 in accordance with an embodiment
of an aspect of the invention. And, FIG. 5 is a wiring diagram
illustrating connection of an obstacle sensor 22 to a controller 26
in accordance with an embodiment of an aspect of the invention.
[0026] The obstacle sensor 22 is a hybrid three electrode sensor
that allows for both a resistive mode and a capacitive mode of
obstacle detection. In general, the resistive mode operates through
the middle (second) and lower (third) electrodes 2, 3. The
capacitive mode operates through the upper (first) and middle
(second) electrodes 1, 2 and/or with all three electrodes 1, 2, 3.
In capacitive mode, the upper and middle electrodes 1, 2 function
in a driven shield configuration (i.e., with the middle electrode 2
being the driven shield) with the lower electrode 3 being an
optional ground. The case 300 positions the three electrodes 1, 2,
3 in an arrangement that facilitates operation of the sensor 22 in
both a capacitive mode and a resistive mode.
[0027] In capacitive mode, the upper electrode 1 (optionally
comprising a conductor 1a embedded in conductive resin 1b) acts as
a capacitive sensor electrode, and the middle electrode 2
(optionally comprising a conductor 2a embedded in conductive resin
2b) acts as a capacitive shield electrode. A dielectric 320 (e.g.,
a portion 320 of the case 300) is disposed between the middle
electrode 2 and the upper electrode 1 to isolate and maintain the
distance between the two. The controller (or sensor processor
("ECU")) 26 is in electrical communication with the electrodes 1, 2
for processing sense data received therefrom.
[0028] In resistive mode, the middle electrode 2 acts as an upper
resistive element and the lower electrode 3 acts as a lower
resistive element. As best shown in FIG. 4, the middle and lower
electrodes 2, 3 are connected at one end of the sensor 22 to a
pre-determined resistor 421 and at the other end to a wire harness
430 and the controller 26. The middle and lower electrodes 2, 3 are
separated by an air gap 330 formed within the case 300 and bounded
by compressible or deflectable spring side walls 301, 302 of the
case 300. When an obstacle contacts the sensor 22 with enough force
and within the activation angle range of the sensor 22, it deflects
the upper portion of the sensor 22 and brings the middle and lower
electrodes 2, 3 into contact. This lowers the resistance of the
sensor 22 to a level that is detectable by the controller 26 which
is in electrical communication with the middle and lower electrodes
2, 3 for processing sense data received therefrom.
[0029] According to one embodiment, the obstacle sensor 22 includes
an elongate non-conductive case 300 having three elongate
conductive electrodes 1, 2, 3 extending along its length. The
electrodes 1, 2, 3 are encapsulated in the case 300 and are
normally spaced apart. When the sensor 22 is compressed in a
direction substantially parallel to its length by an obstacle, the
middle and lower electrodes 2, 3 make contact so as to generate an
electrical signal indicative of contact with the obstacle. When an
obstacle comes between the tailgate 12 and the body 16 of vehicle
14, it effects the electric field generated by the upper electrode
1 which results in a change in capacitance between the upper and
middle electrodes 1, 2 which is indicative of the proximity of the
obstacle to the liftgate 12. Hence, the middle and lower electrodes
2, 3 function as a resistive contact sensor while the upper and
middle electrodes 1, 2 function as a capacitive non-contact or
proximity sensor.
[0030] According to one embodiment, the upper (first) electrode 1
may include a first conductor 1a embedded in a first partially
conductive body 1b, the middle (second) electrode 2 may include a
second conductor 2a embedded in a second partially conductive body
2b, and the lower (third) electrode 3 may include a third conductor
3a embedded in a third partially conductive body 3b. The conductors
1a, 2a, 3a may be formed from a metal wire. The partially
conductive bodies 1b, 2b, 3b may be formed from a conductive resin.
And, the case 300 may be formed from a non-conductive (e.g.,
dielectric) material (e.g., rubber, etc.). Again, the upper
electrode 1 is separated from the middle electrode 2 by a portion
320 of the case 300. The middle electrode 2 is separated from the
lower electrode 3 by an air gap 330 formed in the case 300.
[0031] According to one embodiment, the obstacle sensor 22 is
mounted on the liftgate 12 as shown in FIGS. 1 and 5. The sensor 22
may be fastened to the liftgate 12 by an adhesive tape 340 provided
along the base of the sensor's case 300.
[0032] According to one embodiment, the case 300 may be formed as
an extruded, elongate, elastomeric trim piece with co-extruded
conductive bodies 1b, 2b, 3b and with the conductors 1a, 2a, 3a
molded directly into the bodies 1b, 2b, 3b. The trim piece may be
part of the liftgate water sealing system, i.e., form part of a
seal, it may form part of the decorative fascia of the vehicle 14,
or it may form part of the interior trim of the liftgate 12.
[0033] As shown in FIG. 4, a capacitive sensor circuit 410 is
formed by the capacitive sensor electrode 1, a first terminal
resistor 411, and the capacitive shield/upper resistive sensor
electrode 2. In addition a resistive sensor circuit 420 is formed
by the capacitive shield/upper resistive sensor electrode 2, a
second terminal resistor 421, and the lower resistive sensor
electrode 3. The resistors 411, 421 are diagnostic resistors for
the sensor circuits 410, 420. Both the capacitive sensor circuit
410 and the resistive sensor circuit 420 are coupled to and driven
by the controller 26.
[0034] With respect to resistive sensing, the air gap 330
electrically insulates the middle electrode 2 and the lower
electrode 3. However, the spring side walls 301, 302 of the sensor
case 300 are flexible enough to enable the outer surfaces 2c, 3c of
the partially conductive bodies 2b, 3b of the two electrodes 2, 3
to touch one another when the sensor 22 is compressed (e.g., as a
result of a pinch event). The flexibility of the sensor 22 may be
controlled by its cross sectional configuration, including
controlling the thickness of the side walls 301, 302 of the case
300 and the thickness of the partially conductive bodies 2b, 3b.
The outer surfaces 2c, 3c of the partially conductive bodies 2b, 3b
are shaped to increase the activation angle (i.e., the angle from
the normal at which a compressive or pinch force is applied to the
sensor 22) of the sensor 22. According to one embodiment, the outer
surface 2c of the middle electrode 2 may have a ball shape and the
outer surface 3c of lower electrode 3 may have a socket shape as
shown in FIG. 3.
[0035] The controller 26 measures the resistance (or resistance
value) between the middle electrode 2 and the lower electrode 3.
The resistance will be large in magnitude when the partially
conductive bodies 2b, 3b are separated from each other by the air
gap 330, and will reduce in magnitude if a portion of the partially
conductive bodies 2b, 3b contact one another when the sensor 22 is
compressed. This drop in measured resistance is indicative of
contact with an obstacle (i.e., a pinch event).
[0036] With respect to capacitive sensing, a portion 320 of the
case 300 electrically insulates the upper electrode 1 and the
middle electrode 2 so that electrical charge can be stored
therebetween in the manner of a conventional capacitor. According
to one embodiment, the inner surface 2d of the middle electrode 2
may be shaped to improve the shielding function of the middle
electrode 2. According to one embodiment, the inner surface 2d may
be flat as shown in FIG. 3.
[0037] The sensor 22 is used by the controller 26 to measure a
capacitance (or capacitance value) of an electric field extending
through the opening 500 under the liftgate 12. According to one
embodiment, the middle electrode 2 functions as a shielding
electrode since it is positioned closer to the sheet metal of the
liftgate 12. As such, the electric field sensed by the upper
electrode 1 will be more readily influenced by the closer middle
electrode 2 than the vehicle sheet metal. To improve signal
quality, the liftgate 12 may be electrically isolated from the
remainder of the vehicle 14. A powered sliding door, for example,
may be isolated through the use of non-conductive rollers.
[0038] The capacitance (or capacitance value) of the sensor 22 is
measured as follows. The capacitive sensor electrode 1 and the
capacitive shield/upper resistive sensor electrode 2 are charged by
the controller 26 to the same potential using a pre-determined
pulse train. For each cycle, the controller 26 transfers charge
accumulated between the electrodes 1, 2 to a larger reference
capacitor (not shown), and records an electrical characteristic
indicative of the capacitance of the sensor 22. The electrical
characteristic may be the resultant voltage of the reference
capacitor where a fixed number of cycles is used to charge the
electrodes 1, 2, or a cycle count (or time) where a variable number
of pulses are used to charge the reference capacitor to a
predetermined voltage. The average capacitance of the sensor 22
over the cycles may also be directly computed. When an obstacle
enters the opening 500 under the liftgate 12, the dielectric
constant between the electrodes 1, 2 will change, typically
increasing the capacitance of the sensor 22 and thus affecting the
recorded electrical characteristic. This increase in measured
capacitance is indicative of the presence of the obstacle (i.e.,
its proximity to the liftgate 12).
[0039] FIG. 6 is a flow chart generally illustrating 600 a method
of operating a resistance module and a capacitance module within an
obstacle sensing system 10 for detecting contact with or proximity
of an obstacle, in accordance with an embodiment of an aspect of
the invention. According to one embodiment, as shown in FIG. 6, the
obstacle sensing system 10 may use both capacitive and resistive
sensing modes to detect contact with or proximity of an obstacle.
Software modules within the controller 26 may toggle between
resistive and capacitive sensing operations. For example, the
method beings by 602 initializing the sensor 22 or sensors 22 of
the obstacle sensing system 10, followed by an 604 initiation of a
sample timer. The sample time can include a predetermined cycle
time, such as seconds, in which to check the capacitive and sensing
modes of the sensor(s) 22. Once the sample timer has been
initiated, the method proceeds by 606 checking the resistive sensor
mode of the sensor 22. If a change in the resistance between the
second and third electrodes 2, 3 is detected, the method proceeds
to 608 initiate a "REVERSAL COMMAND" to the drive mechanism to
cease a closing movement of the closure panel. If no change in the
resistance between the second and third electrodes 2, 3 is
detected, the method proceeds by 610 checking the capacitive sensor
mode of the sensor 22. If a change in a capacitance between the
first and second electrodes 1, 2 is detected, the method proceeds
to 608 initiate a "REVERSAL COMMAND" to the drive mechanism to
cease a closing movement of the closure panel. If no change in the
capacitance between the first and second electrodes 1, 2 is
detected, the method proceeds to 602 re-initiate the sample
timer.
[0040] The above embodiments contribute to an improved obstacle
sensor 22 and provide one or more advantages. First, by detecting
proximity of an obstacle by capacitive sensing, overloading of the
sensor 22 and the pinched obstacle during the time lag encountered
by the powered opening of the liftgate 12 is reduced. Second, the
sensor 22 allows for the use of resistive contact sensing as a
back-up to capacitive proximity sensing.
[0041] The foregoing description of the embodiments has been
provided for purposes of illustration and description. It is not
intended to be exhaustive or to limit the disclosure. Individual
elements or features of a particular embodiment are generally not
limited to that particular embodiment, but, where applicable, are
interchangeable and can be used in a selected embodiment, even if
not specifically shown or described. The same may also be varied in
many ways. Such variations are not to be regarded as a departure
from the disclosure, and all such modifications are intended to be
included within the scope of the disclosure.
* * * * *