U.S. patent application number 15/145927 was filed with the patent office on 2016-08-25 for seat assembly with counter for isolating fracture zones in a well.
The applicant listed for this patent is UTEX Industries, Inc.. Invention is credited to Derek Carter, Mark Henry Naedler.
Application Number | 20160245043 15/145927 |
Document ID | / |
Family ID | 49547757 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160245043 |
Kind Code |
A1 |
Naedler; Mark Henry ; et
al. |
August 25, 2016 |
SEAT ASSEMBLY WITH COUNTER FOR ISOLATING FRACTURE ZONES IN A
WELL
Abstract
A specially designed rotary indexing system and associated
operational methods are incorporated in a downhole control device,
representatively a sliding sleeve valve, having an outer tubular
member in which an annular plug seat is coaxially disposed. The
plug seat is resiliently expandable between a first diameter and a
larger second diameter and is illustratively of a circumferentially
segmented construction. The rotary indexing system is operative to
detect the number of plug members that pass through and
diametrically expand the plug seat, and responsively preclude
passage of further plug members therethrough when such number
reaches a predetermined magnitude. Such predetermined magnitude is
correlated to the total rotation of an indexing system counter ring
portion rotationally driven by axial camming forces transmitted to
the rotary indexing system by successive plug member
passage-generated diametrical expansions of the plug seat.
Inventors: |
Naedler; Mark Henry;
(Cypress, TX) ; Carter; Derek; (West Fork,
AR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UTEX Industries, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
49547757 |
Appl. No.: |
15/145927 |
Filed: |
May 4, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13887779 |
May 6, 2013 |
9353598 |
|
|
15145927 |
|
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|
61644887 |
May 9, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 2200/06 20200501;
E21B 33/13 20130101; E21B 43/261 20130101; E21B 33/128 20130101;
E21B 43/14 20130101; E21B 33/134 20130101; E21B 34/14 20130101 |
International
Class: |
E21B 34/14 20060101
E21B034/14; E21B 43/14 20060101 E21B043/14; E21B 33/128 20060101
E21B033/128; E21B 33/134 20060101 E21B033/134; E21B 43/26 20060101
E21B043/26; E21B 33/13 20060101 E21B033/13 |
Claims
1. A control apparatus operably positionable in a wellbore,
comprising: a tubular member extending along an axis; an annular
seat structure coaxially supported within the tubular member and
being diametrically expandable by a plug member passing axially
therethrough from a first diameter small enough to block passage of
the plug member through the annular seat structure to a second
diameter permitting the plug member to pass through the annular
seat structure, and then being contractible to the first diameter;
and a counter apparatus operative to lock the annular seat
structure at the first diameter in response to a predetermined
number of plug members having passed through and diametrically
expanding the annular seat structure to the second diameter, the
counter apparatus including: a first portion rotationally indexable
about the axis; a second portion operative, in response to a
diametric expansion of the annular seat structure to the second
diameter, to engage and rotationally index the first portion
through a predetermined angle about the axis; and a third portion
separated from the first portion by an axially extending separator
that separates and prevents one of the first and third portions
from displacing toward the other of the first and third portions,
one of the first and third portions having a separator receiver
that receives the axially extending separator when the separator
receiver aligns with the axially extending separator in a manner
that one of the first and third portions displaces towards the
other of the first and third portions and lock the annular seat
structure at the first diameter.
2. The control apparatus of claim 1, wherein the axially extending
separator is an axially extending male protrusion, and wherein the
separator receiver is an axially extending female recess in an edge
of one of the first and third portions.
3. The control apparatus of claim 1, wherein the axially extending
separator is a first separator, the control apparatus comprising a
second axially extending separator disposed between the first and
third portions.
4. The control apparatus of claim 1, wherein the separator receiver
is an axially extending female recess, and the axially extending
separator is an axially extending male protrusion, the first
portion rotationally indexable about the axis until the male
protrusion aligns with and enters the female recess so that one of
the first and third portions displaces towards the other of the
first and third portions.
5. The control apparatus of claim 1, wherein the first portion
comprises a first end region including a plurality of first cam
surfaces and an opposing second end region including a plurality of
second cam surfaces, the first portion being rotationally indexable
as a result of a pin structure engaging either of the plurality of
first cam surfaces or the plurality of second cam surfaces.
6. The control apparatus of claim 1, further comprising a radially
extending pin carried on the second portion that engages the first
portion and rotationally indexes the first portion about the
axis.
7. The control apparatus of claim 1, wherein the control apparatus
is a sliding sleeve valve.
8. The control apparatus of claim 1, wherein the annular seat
structure is resiliently expandable from the first diameter to the
second diameter.
9. The control apparatus of claim 8, wherein the annular seat
structure is of a circumferentially segmented construction.
10. The control apparatus of claim 9, wherein, the annular seat
structure includes a series of rigid circumferential segments
carrying an elastomeric material resiliently biasing the annular
seat structure radially inwardly toward the first diameter
thereof.
11. The control apparatus of claim 1, further comprising a first
biasing element biasing the second portion in a first axial
direction and a second biasing element biasing the third portion in
an opposing axial direction.
12. The control apparatus of claim 1, wherein the second biasing
member comprises a pocket arranged to receive the annular seat
structure when it expands to the second diameter.
13. A control apparatus operably positionable in a wellbore,
comprising: a tubular member extending along an axis; an annular
plug seat coaxially disposed within the tubular member and being
diametrically expandable from a first diameter to a larger second
diameter by a plug member passing axially therethrough in a
downstream direction; and a rotationally indexable counter
apparatus functioning, during an operational cycle of the control
apparatus, to limit to a predetermined number the number of times
the annular plug seat can be diametrically expanded from the first
diameter to the second diameter by plug members sequentially
passing through the annular plug seat in the downstream direction,
the rotationally indexable counter apparatus comprising a counting
ring rotationally indexable about the axis, the counting ring
having at least one cam surface therein for incrementally rotating
the counting ring about the axis; a locking ring separated from the
counting ring by an axially extending male protrusion that
separates and prevents the counting and locking rings from
displacing toward each other, and one of the counting and locking
rings having an axially extending female recess formed therein that
receives the axially extending male protrusion when the female
recess aligns with the male protrusion in a manner permitting the
counting and locking rings to displace towards each other and lock
the annular plug seat at the first diameter.
14. The control apparatus of claim 13, comprising an upper piston
arranged to be axially displaced when the annular plug seat expands
to the second diameter and to simultaneously rotate the counting
ring.
15. The control apparatus of claim 14, wherein the upper piston
comprises a radially extending pin that engages the cam surface to
incrementally rotate the counting ring about the axis.
16. The control apparatus of claim 14, further comprising a first
biasing element biasing the counting ring in a first axial
direction and a second biasing element biasing the upper piston in
an opposing axial direction.
17. The control apparatus of claim 13, wherein the counting ring
comprises a first end region including a plurality of first cam
surfaces and an opposing second end region including a plurality of
second cam surfaces, the counting being rotationally indexable as a
result of pin structures alternatingly engaging both of the
plurality of first cam surfaces and the plurality of second cam
surfaces.
18. A control apparatus operably positionable in a wellbore,
comprising: a tubular member extending along an axis; an annular
plug seat coaxially disposed within the tubular member and being
diametrically expandable from a first diameter to a larger second
diameter by a plug member passing axially therethrough in a
downstream direction; and a rotationally indexable counter
apparatus functioning to limit the number of times the annular plug
seat can be diametrically expanded from the first diameter to the
second diameter by plug members sequentially passing through the
annular plug seat, the rotationally indexable counter apparatus
comprising: a counting ring rotationally indexable about the axis;
a piston ring operative, in response to a diametric expansion of
the annular seat structure to the second diameter, to engage and
rotationally index the counting ring through a predetermined angle
about the axis; a first spring biasing the piston ring away from
the counting ring; a locking ring separated from the counting ring
by an axially extending male protrusion that separates and prevents
the counting and locking rings from displacing toward each other,
one of the counting and locking rings having an axially extending
female recess formed therein that receives the axially extending
male protrusion when the female recess aligns with the male
protrusion in a manner permitting the counting and locking rings to
displace towards each other and lock the annular plug seat at the
first diameter; and a second spring biasing the locking ring toward
the counting ring.
19. The control apparatus of claim 18, comprising an upper piston
arranged to be axially displaced when the annular plug seat expands
to the second diameter and to simultaneously rotate the counting
ring.
20. The control apparatus of claim 18, wherein the upper piston
comprises a radially extending pin that engages the cam surface to
incrementally rotate the counting ring about the axis.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation application of
U.S. patent application Ser. No. 13/887,779 filed May 6, 2013,
which claims the benefit of the filing date of provisional U.S.
patent application No. 61/644,887 filed May 9, 2012, each of which
is incorporated herein by reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to a fracture plug seat
assembly used in well stimulation for engaging and creating a seal
when a plug, such as a ball, is dropped into a wellbore and landed
on the fracture plug seat assembly for isolating fracture zones in
a well. More particularly, the present invention relates to a
fracture plug seat assembly that includes a mechanical counter
allowing plugs to pass through the seat then locking to a rigid
seat position after a designated number of plugs from the surface
have passed through the seat. The locking mechanism disengages when
flow is reversed and plugs are purged.
BACKGROUND
[0003] In well stimulation, the ability to perforate multiple zones
in a single well and then fracture each zone independently,
referred to as "zone fracturing", has increased access to potential
reserves. Zone fracturing helps stimulate the well by creating
conduits from the formation for the hydrocarbons to reach the well.
Many gas wells are drilled for zone fracturing with a system called
a ball drop system planned at the well's inception. A well with a
ball drop system will be equipped with a string of piping below the
cemented casing portion of the well. The string is segmented with
packing elements, fracture plugs and fracture plug seat assemblies
to isolate zones. A fracture plug, such as a ball or other suitably
shaped structure (hereinafter referred to collectively as a "ball")
is dropped or pumped down the well and seats on the fracture plug
seat assembly, thereby isolating pressure from above.
[0004] Typically, in ball drop systems a fracture plug seat
assembly includes a fracture plug seat having an axial opening of a
select diameter. To the extent multiple fracture plugs are disposed
along a string, the diameter of the axial opening of the respective
fracture plug seats becomes progressively smaller with the depth of
the string. This permits a plurality of balls having a
progressively increasing diameter, to be dropped (or pumped),
smallest to largest diameter, down the well to isolate the various
zones, starting from the toe of the well and moving up.
[0005] A large orifice through an open seat is desired while
fracing zones below that seat. An unwanted consequence of having
seats incrementally smaller as they approach the toe is the
existence of pressure loss across the smaller seats. The pressure
loss reduces the efficiency of the system and creates flow
restrictions while fracing and during well production.
[0006] In order to maximize the number of zones and therefore the
efficiency of the well, the difference in the diameter of the axial
opening of adjacent fracture plug seats and the diameter of the
balls designed to be caught by such fracture plug seats is very
small, and the consequent surface area of contact between the ball
and its seat is very small. Due to the high pressure that impacts
the balls during a hydraulic fracturing process, the balls often
become stuck and are difficult to purge when fracing is complete
and the well pressure reverses the flow and produces to the
surface. If a ball is stuck in the seat and cannot be purged, the
ball(s) must be removed from the string by costly and
time-consuming milling or drilling processes.
[0007] FIG. 1 illustrates a prior art fracture plug seat assembly
10 disposed along a tubing string 12. Fracture plug seat assembly
10 includes a metallic, high strength composite or other rigid
material seat 14 mounted on a sliding sleeve 16 which is movable
between a first position and a second position. In the first
position shown in FIG. 1, sleeve 16 is disposed to inhibit fluid
flow through radial ports 18 from annulus 20 into the interior of
tubing string 12. Packing element 24 is disposed along tubing
string 12 to restrict fluid flow in the annulus 20 formed between
the earth 26 and the tubing string 12.
[0008] FIG. 2 illustrates the prior art fracture plug seat assembly
10 of FIG. 1, but with a ball 28 landed on the metallic, high
strength composite or other rigid material seat 14 and with sliding
sleeve 16 in the second position. With ball 28 landed on the
metallic, high strength composite or other rigid material seat 14,
fluid pressure 30 applied from uphole of fracture plug seat
assembly 10 urges sliding sleeve 16 into the second position shown
in FIG. 2, thereby exposing radial ports 18 to permit fluid flow
therethrough, diverting the flow to the annulus 20 formed between
the earth 26 and the tubing string 12.
[0009] As shown in FIGS. 1 and 2, the metallic, high strength
composite or other rigid material seat 14 has a tapered surface 32
that forms an inverted cone for the ball or fracture plug 28 to
land upon. This helps translate the load on the ball 28 from shear
into compression, thereby deforming the ball 28 into the metallic,
high strength composite or other rigid material seat 14 to form a
seal. In some instances, the surface of such metallic, high
strength composite or other rigid material seats 14 have been
contoured to match the shape of the ball or fracture plug 28. One
drawback of such metallic, high strength composite or other rigid
material seats 14 is that high stress concentrations in the seat 14
are transmitted to the ball or fracture plug 28. For various
reasons, including specific gravity and ease of milling, balls or
fracture plugs 28 are often made of a composite plastic or
aluminum. Also, efforts to maximize the number of zones in a well
has reduced the safety margin of ball or fracture plug failure to a
point where balls or fracture plugs can extrude, shear or crack
under the high pressure applied to the ball or fracture plug during
hydraulic fracturing operations. As noted above, when the balls 28
extrude into the metallic, high strength composite or other rigid
material seat 14 they become stuck. In such instances, the back
pressure from within the well below is typically insufficient to
purge the ball 28 from the seat 14, which means that an expensive
and time-consuming milling process must be conducted to remove the
ball 28 from the seat 14.
[0010] Other prior art fracture plug seat assembly designs include
mechanisms that are actuated by sliding pistons and introduce an
inward pivoting mechanical support beneath the ball. These designs
also have a metallic, high strength composite or other rigid
material seat, but are provided with additional support from the
support mechanism. These fracture plug seat assembly designs can be
described as having a normally open seat that closes when a ball or
fracture plug is landed upon the seat. Such normally open fracture
plug seat assembly designs suffer when contaminated with the heavy
presence of sand and cement. They also rely upon incrementally
sized balls so such systems suffer from flow restriction and
require post frac milling.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a prior art fracture plug seat assembly
positioned in a well bore.
[0012] FIG. 2 illustrates the prior art fracture plug seat assembly
of FIG. 1 with a ball landed on the seat of the fracture plug seat
assembly.
[0013] FIG. 3 illustrates a cross-section of a fracture plug seat
assembly incorporating an embodiment of the present invention with
a cam driven rotating counter in the unlocked position.
[0014] FIG. 4 illustrates a cross-section of the fracture plug seat
assembly illustrated in FIG. 3 with a ball passing through the
assembly and actuating an expandable seat.
[0015] FIG. 5 illustrates a side view of an embodiment of a
counting mechanism of the present invention for use in a fracture
plug seat assembly with a semi-translucent counting ring.
[0016] FIG. 6 illustrates an isometric view of an embodiment of a
counting ring of the present invention for use in a fracture plug
seat assembly.
[0017] FIG. 7 illustrates a side view of the embodiment of a
counting mechanism of the present invention illustrated in FIG. 5
with the components in position to actuate the counter.
[0018] FIG. 8 illustrates a side view of the embodiment of a
counting mechanism of the present invention illustrated in FIG. 5
with a locking ring in a locked position.
[0019] FIG. 9 illustrates a cross-section of the fracture plug seat
assembly illustrated in FIG. 3 with a locking ring in a locked
position.
[0020] FIG. 10 illustrates a cross-section of the fracture plug
seat assembly illustrated in FIG. 9 with a ball plugging the
seat.
[0021] FIG. 11 illustrates a cross-section of the fracture plug
seat assembly illustrated in FIG. 9 with a ball purging to the
surface.
[0022] FIG. 12 is a cross-section of a fracture plug seat assembly
of the present invention.
DETAILED DESCRIPTION
[0023] The method and apparatus of the present invention provides a
fracture plug seat assembly used in well stimulation for engaging
and creating a seal when a plug, such as a ball, is dropped into a
wellbore and landed on the fracture plug seat assembly for
isolating fracture zones in a well. The fracture plug seat assembly
has a fracture plug seat that includes an expandable ring that
enables the seat to expand when a ball passes through and actuates
a counting mechanism so that balls are allowed to pass until the
counting mechanism reaches a predetermined position which will
enable the actuation of a locking mechanism. When actuated, the
locking mechanism prevents expansion of the seat when the next ball
lands on the seat and pressure is applied from the upstream
direction. When flow is reversed, the seat is free to disengage
from the locking mechanism and allow expansion and hence, balls
that had previously passed through the seat pass through from
downstream and return to the surface.
[0024] According to the fracture plug seat assembly of the present
invention, all balls have the same size and, therefore, flow
restriction is greatly reduced at the lower zones, since the seat
orifices do not become incrementally smaller. Also, according to
the fracture plug seat assembly of the present invention, when
dropping balls from the surface, it is not required to drop
sequential ball sizes which eliminates a potential source of
errors. Moreover, only one size of seat assembly and ball must be
manufactured, instead of sometimes 40 different sizes, making
manufacturing more cost effective. Finally, according to the
fracture plug seat assembly of the present invention, the resulting
production flow from the string can eliminate the need to mill out
the seats.
[0025] FIG. 3 illustrates a cross-section of a fracture plug seat
assembly incorporating an embodiment of the present invention.
Specifically, sliding sleeve assembly 40 is illustrated in a
position to receive balls which will pass through and be counted.
Sliding sleeve 41 is sealably retained within a tubing string. A
segmented expandable seat assembly 42 is in a first closed position
and positioned between a lower seat nut 43 and an upper piston 44.
The lower seat nut 43 is threadably connected to and does not move
relative to the sliding sleeve 41. The upper piston 44 is biased in
the downstream direction 51 against the seat assembly 42 by a
spring 46. The spring 46 engages a shoulder 45 on the sliding
sleeve 41.
[0026] FIG. 4 illustrates the fracture plug seat assembly of FIG. 3
with a ball 50 passing through the sliding sleeve assembly 40 in
the direction 51 with the direction of flow moving upstream to
downstream. In FIG. 4, the ball 50 is engaged with the expandable
seat assembly 42 and has driven the seat radially outward into a
pocket 52 of a locking ring 53. The upper piston 44 is wedged to
move in the upstream direction 54 and further compresses the spring
46. When the upper piston 44 moves in the upstream direction 54 it
actuates a counting ring 55 via radial pins 56 which are rigidly
connected to the upper piston 44 by engaging a cam surface 57
located on the end of the counting ring 55. FIG. 5 illustrates an
embodiment for actuating the counting ring 55. As the radial pins
56 move axially in the upstream direction 54 and into the counting
ring 55, the counting ring 55, which is shouldered axially to the
sliding sleeve 41 is forced to rotate as the radial pins 56 slide
along the cam surface 57. When the ball 50 has passed through the
expandable seat assembly 42, the spring 46 forces the upper piston
44 to return to the position shown in FIG. 3. According to the
counting mechanism embodiment illustrated in FIG. 5, a second set
of radial pins 58 engages a cam surface 59 on the upstream end of
the counting ring 55 and force further rotation of the counting
ring 55 by sliding across the cam surface 59. As shown in FIG. 7,
axial pin(s) 61 prevent the counting ring 55 from moving in the
downstream direction since they are rigidly connected to the
locking ring 53 which is biased in the upstream direction 54 by
spring 63 (FIG. 3).
[0027] FIG. 6 illustrates an isometric view of the downstream side
of counting ring 55. As depicted, counting ring 55 has two
synchronized sets of cam surfaces 57, each set spanning nearly 180
degrees. Two holes 60 are located in the downstream face of the
counting ring 55. As shown in FIG. 7, a partially translucent
counting ring 55 is shown in a side view with a radial pin 56
engaging a cam surface 57. Also, as shown in FIG. 7, yet another
radial pin 64 keeps the locking ring 53 from rotating relative to
the upper piston 44. FIG. 7 is consistent with the position shown
in FIG. 4. Further, as shown in FIG. 7, an axial pin 61 is fixed to
the locking ring 53 and slides across the smooth surface 62 of
counting ring 55 (FIG. 6). An additional axial pin is diametrically
opposite the axial pin 61 and is fixed to the locking ring 53 and
slides across the smooth surface 62 of counting ring 55. When a
predetermined number of balls have passed through the seat assembly
42 and have thus rotated the counting ring 55 in relation to the
locking ring 53, the pin(s) 61 engage hole(s) 60 and a spring 63
(FIG. 3) forces the locking ring 53 in the upstream direction 54,
as shown in FIG. 8. FIG. 9 shows the sliding sleeve assembly 40 in
the position where the locking ring 53 has shifted upstream and is
in contact with the counting ring 55. The pocket 52 is no longer in
a position to allow expansion of the expandable seat assembly 42
from a ball passing in the direction 51. FIG. 10 illustrates the
sliding sleeve assembly 40 with a ball 70 that has landed on the
expandable seat assembly 42 when the locking ring 53 is in the
locked position. The expandable seat assembly 42 is restricted from
expanding due to the locking ring 53 and hence the ball 70 cannot
pass in the downstream direction 51. A seal 71 can assist in
preventing fluid from passing by the ball 70 in the downstream
direction 51 and a seal 73 prevents fluid from passing between the
upper piston 44 and the sliding sleeve 41. Pressure applied to the
ball in the downstream direction 51 results in the force necessary
to actuate the sliding sleeve assembly 40 to an opened position so
its corresponding zone can be fractured.
[0028] When pressure in the downstream direction is relieved, the
ball 70 is purged to the surface in the direction 54 by accumulated
pressure from downstream. FIG. 11 illustrates a ball 72 that had
previous passed through the sliding sleeve assembly 40 in the
downstream direction 51 and actuated the counting ring 55. Now
pressure from the downstream side of the ball 72 forces the
expandable seat assembly 42 to slide in the upstream direction 54
until it reaches the pocket 52. Ball 72 can now pass through the
expandable seat assembly 40 and freely purge to the surface.
[0029] FIG. 12 is a cross-section of a fracture plug seat assembly
of the present invention in a position ready to count a ball. As
shown in FIG. 12, an upper wave spring 83 which helically spirals
around axis 84, biases an upper piston 81 in the downstream
direction 51. A wave spring 85 similar to the upper wave spring 83
biases a locking ring 82 in the upstream direction 54. An
expandable seat assembly 94 is clamped by the biased upper piston
81 and a lower seat nut 93 into a cinched position. The expandable
seat assembly 94 is free to expand into a pocket 95 when a ball
passes through. When a ball actuates the expandable seat assembly
94, the upper piston 81 carries radial pins 96 into a cam profile
of counting ring 97 to initiate rotation of the counting ring 97.
After the final ball to be counted passes through the expandable
seat assembly 94, an axial pin 98 falls into a mating hole in
counting ring 97 and the locking ring 82 is free to be pushed in
the upstream direction 54 by the wave spring 85.
[0030] Also illustrated in FIG. 12 are an upper wiper seal 86, a
lower seal 87 and a nut seal 88. According to the embodiment shown
in FIG. 12, both upper wiper seal 86 and lower seal 87 engage the
upper piston 81 at the same diameter so there is no change in
volume in annulus 89 when the upper piston 81 is actuated. While
not essential to the function of this embodiment of the fracture
plug seat assembly, this embodiment resists the accumulation of
dirty fluid in the annulus 89. Also, the nut seal 88 guards against
the incursion of debris into the space 91. Expandable seat assembly
94 may be formed from any suitable material such as a segmented
ring of drillable cast iron. Those of ordinary skill in the art
will understand that the expandable seat assembly 94 may also be
encapsulated in rubber so as to guard against the entry of
contaminants into pocket 95 and to shield the cast iron from the
abrasive fluid passing through the expandable seat assembly 94.
[0031] It is to be understood that the means to actuate the counter
could be a lever or radial piston that is not integrated into the
expandable seat. It is convenient to use the expandable seat as the
mechanism to actuate the counter. It is also to be understood that
the counter could actuate a collapsible seat.
[0032] It is understood that variations may be made in the
foregoing without departing from the scope of the disclosure.
[0033] In several exemplary embodiments, the elements and teachings
of the various illustrative exemplary embodiments may be combined
in whole or in part in some or all of the illustrative exemplary
embodiments. In addition, one or more of the elements and teachings
of the various illustrative exemplary embodiments may be omitted,
at least in part, and/or combined, at least in part, with one or
more of the other elements and teachings of the various
illustrative embodiments.
[0034] Any spatial references such as, for example, "upper,"
"lower," "above," "below," "between," "bottom," "vertical,"
"horizontal," "angular," "upwards," "downwards," "side-to-side,"
"left-to-right," "left," "right," "right-to-left," "top-to-bottom,"
"bottom-to-top," "top," "bottom," "bottom-up," "top-down," etc.,
are for the purpose of illustration only and do not limit the
specific orientation or location of the structure described
above.
[0035] In several exemplary embodiments, while different steps,
processes, and procedures are described as appearing as distinct
acts, one or more of the steps, one or more of the processes,
and/or one or more of the procedures may also be performed in
different orders, simultaneously and/or sequentially. In several
exemplary embodiments, the steps, processes and/or procedures may
be merged into one or more steps, processes and/or procedures. In
several exemplary embodiments, one or more of the operational steps
in each embodiment may be omitted. Moreover, in some instances,
some features of the present disclosure may be employed without a
corresponding use of the other features. Moreover, one or more of
the above-described embodiments and/or variations may be combined
in whole or in part with any one or more of the other
above-described embodiments and/or variations.
[0036] Although several exemplary embodiments have been described
in detail above, the embodiments described are exemplary only and
are not limiting, and those skilled in the art will readily
appreciate that many other modifications, changes and/or
substitutions are possible in the exemplary embodiments without
materially departing from the novel teachings and advantages of the
present disclosure. Accordingly, all such modifications, changes
and/or substitutions are intended to be included within the scope
of this disclosure as defined in the following claims. In the
claims, any means-plus-function clauses are intended to cover the
structures described herein as performing the recited function and
not only structural equivalents, but also equivalent
structures.
* * * * *