U.S. patent number 3,915,426 [Application Number 05/412,771] was granted by the patent office on 1975-10-28 for blowout preventer with variable inside diameter.
This patent grant is currently assigned to Hydril Company. Invention is credited to Robert K. LeRouax.
United States Patent |
3,915,426 |
LeRouax |
* October 28, 1975 |
Blowout preventer with variable inside diameter
Abstract
A variable inside diameter blowout preventer capable of sealing
off a bore or around an object against high well pressures, and
which may be either a ram-type preventer or an annular preventer,
and wherein a plurality of upper and lower anti-extrusion members
are each disposed in two overlapping layers and are mounted for
radial movement to and from a sealing position and an open
position, with the anti-extrusion members inhibiting extrusion of a
resilient sealing member therewith throughout a predetermined range
of variable inside diameters of the sealing member and
anti-extrusion members.
Inventors: |
LeRouax; Robert K. (Houston,
TX) |
Assignee: |
Hydril Company (N/A)
|
[*] Notice: |
The portion of the term of this patent
subsequent to July 29, 1992 has been disclaimed. |
Family
ID: |
26985655 |
Appl.
No.: |
05/412,771 |
Filed: |
November 5, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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326965 |
Jan 26, 1973 |
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Current U.S.
Class: |
251/1.1; 277/324;
251/1.2 |
Current CPC
Class: |
E21B
33/06 (20130101); E21B 33/062 (20130101) |
Current International
Class: |
E21B
33/06 (20060101); E21B 33/03 (20060101); E21B
033/06 () |
Field of
Search: |
;251/1
;277/73,126,127,129,181,185,188,235 ;166/81,82,84,86,88 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schwadron; Martin P.
Assistant Examiner: Gerard; Richard
Attorney, Agent or Firm: Pravel & Wilson
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent
application Ser. No. 326,965 filed Jan. 26, 1973, copending
herewith, and now abandoned.
Claims
I claim:
1. A blowout preventer adapted to seal with a pipe or other object
in a well bore or to close same in the absence of any object in the
well bore, comprising:
a resilient sealing member having an inner curved surface adapted
to engage a pipe or the like in a well bore;
means for urging said sealing member radially inwardly for
effecting a seal with a pipe or the like in a well bore or with
itself for closing a well bore; and
first anti-extrusion means mounted with said sealing member and
movable radially therewith in response to radial inward movement of
said sealing member for preventing extrusion of the sealing member
longitudinally when fluid pressure acts on said sealing member,
said first anti-extrusion means comprising:
a first set of anti-extrusion members circumferentially disposed
with respect to each other and mounted for radial movement;
a second set of anti-extrusion members, mounted below said first
set and staggered circumferentially with respect to said
anti-extrusion members in said first set to close radial spaces
therebetween; and
separate connector means connecting said first set of
anti-extrusion members to said second set for effecting radial
movement thereof together.
2. The blowout preventer set forth in claim 1, wherein:
said sealing member is substantially semi-cylindrical and is
adapted to be mounted as a part of a blowout preventer ram.
3. The blowout preventer set forth in claim 1, wherein said sealing
member is annular.
4. The blowout preventer set forth in claim 1, including:
second anti-extrusion means mounted with said sealing member on the
opposite side longitudinally of said sealing member from said first
anti-extrusion means and movable radially relative to said sealing
member in response to radial inward movement of said sealing member
for inhibiting extrusion of the sealing member longitudinally when
fluid pressure acts on said sealing member from either longitudinal
direction.
5. The structure set forth in claim 4, wherein said second
anti-extrusion means includes:
a first set of anti-extrusion members circumferentially disposed
with respect to each other and mounted for radial movement;
a second set of anti-extrusion members mounted below said first set
and staggered circumferentially with respect to said anti-extrusion
members in said first set to close radial spaces therebetween;
and
said anti-extrusion members in such first and second sets having
overlapping surfaces, the extent of overlap of which increases as
the anti-extrusion members move radially inwardly.
6. The structure set forth in claim 5, wherein:
each of said anti-extrusion members in said second set of
anti-extrusion members of said second anti-extrusion means is
bonded to said sealing member and is movable therewith; and
connector means connecting said first set of anti-extrusion members
in said second anti-extrusion means to said second set for
effecting radial movement thereof together.
7. The structure set forth in claim 6, wherein said connector means
includes:
a connector plate secured to each of said anti-extrusion members in
said second set for movement therewith; and
circumferential slide connection means connecting said connector
plate to each of two of the anti-extrusion members in said first
set above the anti-extrusion member in said second set to which
said plate is secured for thereby providing limited circumferential
movement of said connected members relative to each other as they
move together radially.
8. The structure set forth in claim 1, wherein:
said anti-extrusion members in said first and second sets having
overlapping surfaces, the extent of overlap of which increases as
the anti-extrusion members move radially inwardly.
9. The structure set forth in claim 8, wherein:
each of said anti-extrusion members in said second set of
anti-extrusion members of said first anti-extrusion means is bonded
to said sealing member and is movable therewith.
10. The structure set forth in claim 1, wherein said separate
connector means includes:
a connector plate secured to each of said anti-extrusion members in
said second set for movement therewith; and
circumferential slide connection means connecting said connector
plate to each of two of the anti-extrusion members in said first
set above the anti-extrusion member in said second set to which
said plate is secured for thereby providing limited circumferential
movement of said connected members relative to each other as they
move together radially.
11. The structure set forth in claim 10, wherein said
circumferential slide connection means includes:
a circumferential slot in each said connector plate for each of
said two anti-extrusion members in said first set; and
a pin with each of said two anti-extrusion members in said first
set extending through said slot and having a head thereon to force
the anti-extrusion members in said first set to move radially with
the anti-extrusion members in said second set while permitting
relative circumferential movement during such radial movement.
Description
BACKGROUND OF THE INVENTION
The field of this invention is blowout preventers for oil wells and
the like.
Annular blowout preventers made by the Hydril Company, an example
of which is shown on page 2742 of the "Composite Catalog" for
1970-71, have been in extensive commercial use for a number of
years. Such blowout preventers provide a fully-open bore
therethrough so that drill bits, reamers, casing hangers and other
large diameter tools can freely pass therethrough, but when
actuated to the closed position, the packing of each such preventer
is forced inwardly to reduce its bore and automatically adjust its
size and shape in sealing contact with whatever object happens to
then be in the bore of the preventer, thereby closing off the
annular space around such object to prevent a blowout of well
pressure from below. If no tool is in the well, the bore of the
preventer can be fully closed to prevent a blowout.
Although such Hydril blowout preventers are very satisfactory for
relatively low well pressures in the range of from about 2,000
p.s.i. to 5,000 p.s.i., it is generally desirable to use a ram type
blowout preventer above such pressures, and above 10,000 p.s.i.
well pressure, it has heretofore been considered essential to use a
ram type blowout preventer of a predetermined opening size because
of the inability to satisfactorily prevent extrusion of the rubber
of the preventers at such higher pressures.
SUMMARY OF THE INVENTION
The present invention relates to blowout preventers wherein a
resilient sealing member or members are provided for closing a well
bore or sealing with a pipe or other object disposed in the bore
and wherein anti-extrusion means are mounted with the sealing
member or members to prevent extrusion thereof over a relatively
large variable range of bore diamters for the preventer, and
wherein the blowout preventers of this invention may be of the ram
type or the annular type, and are yet capable of sealing off much
higher well pressures than with prior known annular blowout
preventers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical sectional view illustrating one embodiment of
the blowout preventer of this invention in the retracted or opened
position;
FIG. 2 is a view similar to that of FIG. 1 illustrating the blowout
preventer in the closed or sealing position with a pipe in the well
bore;
FIG. 3 is a view taken on line 3--3 of FIG. 1 to illustrate in
particular the anti-extrusion means of the blowout preventer of
this invention;
FIG. 4 is a view taken on line 4--4 to further illustrate the
anti-extrusion means of FIG. 3 when in the contracted position with
the sealing means in sealing contact with the well pipe;
FIG. 5 is a view taken on line 5--5 of FIG. 3;
FIG. 5A is a view taken on line 5A--5A of FIG. 4;
FIG. 6 is an isometric view of the upper anti-extrusion means used
with the blowout preventer of this invention in the annular or
cylindrical form thereof;
FIG. 7 is a vertical sectional view of the blowout preventer of
this invention in the ram type preventer;
FIG. 8 is a view taken on line 8--8 and illustrating a portion of
the blowout preventer of this invention in the ram type; and
FIG. 9 is an isometric view, partly exploded, illustrating the
upper anti-extrusion means used with the ram type blowout preventer
of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, the letter B refers generally to the form of the
blowout preventer of this invention shown in FIGS. 1-6.
Briefly, the preventer B includes a housing H which has a central
longitudinal bore 10 through which a pipe P or other object is
adapted to extend in the known manner for well operations. The
housing H is constructed so that it is positioned in a stack of
blowout preventers or in a string of well casing or pipe in any
suitable manner, as will be understood by those skilled in the art.
The blowout preventer B has a replaceable assembly A, the details
of which will be described hereinafter, which has a central bore 11
which is preferably at least as large as the central opening or
bore 10 and which is likewise substantially the same size or at
least as large as the bore of the casing or pipe above and below
the preventer B so that a full opening bore 11 is available for the
passage of the pipe P and other well tools during normal
operations.
Considering the details of the blowout preventer B, the housing H
may take numerous forms, but as illustrated in the drawings, it
includes a lower housing section 12 having a housing recess 12a for
receiving the blowout preventer assembly A and an annular piston 14
formed of rubber or similar material, as will be further explained.
The recess 12a is further defined by a housing section or cover 15
which is secured to the housing section 12 by bolts 15a (FIG. 1) or
other suitable securing means. A fluid line 12b and a fluid relief
line 15b communicates through the housing H with the recess 12a for
the inlet and relief of hydraulic or other fluid pressure with
respect to the resilient piston 14 to control the opening and
closing of the blowout preventer B, as will be more evident
hereinafter. For connecting the housing H in a stack of blowout
preventers, or to suitable flanges of the well pipe or casing above
and below the blowout preventer B, connecting threaded studs 12c
and 15c are preferably provided, although any other suitable
connecting means may be employed. Connecting studs 15c are
preferably disposed longitudinally in alignment with the connecting
studs 12c, although this is not essential.
The replaceable assembly A includes an annular resilient yieldable
sealing element or member 30 formed of rubber or other similar
yieldable material and preferably having a dished out or concave
inner annular surface 30a. An upper anti-extrusion means M is
provided with the seal member 30, and a lower anti-extrusion means
M' is also provided with the seal member 30, as will be more fully
explained. The upper anti-extrusion means M is preferably identical
to the lower anti-extrusion means M' in the preferred form of the
invention, except that they are upside down with respect to each
other. Therefore, the details of the anti-extrusion means M will be
hereinafter explained and the same parts will be identified with
the same numerals and/or letters followed by a prime mark for the
lower anti-extrusion means M'.
The upper anti-extrusion means M is illustrated in detail in FIGS.
3-6. Such anti-extrusion means M includes an upper or first set of
anti-extrusion members 35 which together form an annular or
cylindrical assembly (FIG. 6). In fact, the members 35 may be cut
or otherwise formed from a single solid cylindrical member or ring.
The radial edges or sides 35a of each of the members or segments 35
are disposed radially and if extended would all converge at a
single point in the center of the bore or opening defined by such
segments 35. The inner surfaces 35b of the segments or members 35
form the inner bore of the upper or first set of the anti-extrusion
members 35, which bore may vary from its smallest diameter (FIG. 6)
to a larger retracted diameter (FIGS. 1 and 3).
The outer surface 35c of each of the members or segments 35 is
likewise formed in a cylindrical surface with the other surfaces
35c and in the preferred form of the invention, a pair of threaded
openings 35d are provided in such surface 35c of each segment 35
for a purpose to be hereinafter explained.
The upper anti-extrusion means M also includes a second or lower
set of anti-extrusion members or segments 36 which are likewise
formed in a substantially cylindrical or annular shape as a ring
when assembled in their innermost contracted position (FIG. 6) and
which are adapted to move outwardly to a larger inner bore diameter
as shown in FIGS. 1 and 3. The members 36 are staggered or are
spaced alternately with respect to the members 35 so that the
radial edges 35a of the segments 35 are disposed substantially
midway of the segments or members 36 when the segments 35 are in
their retracted position of FIG. 6. The sides or edges 36a of the
segments 36 extend substantially radially although they are also
preferably inclined as shown in the drawings since the lowermost
surface 36d of each segment 36 is bonded or is otherwise secured to
the rubber or other material of the sealing element 30, and such
inclined surfaces 36a provides room for some distortion of the
rubber of the sealing element 30 without binding the movements of
the members 36. The inner surfaces 36b of the segments 36 are
preferably disposed coextensively with the surfaces 35b so as to
form a bore which is of the same diameter as the bore formed by the
surfaces 35b. Also, as will be explained, the surfaces 35b and 36b
remain vertically aligned during the radial movement of the
segments 35 and 36 from the open position to the closed position of
the blowout preventer B and vice versa. Each of the segments 36 has
an outer surface 36c which is formed with one or more openings 36e,
the purpose of which will be hereinafter explained.
The segments 35 and 36 are connected together so that they may move
radially from the enlarged or retracted position of FIGS. 1 and 3
to the maximum closed position of FIGS. 4 and 6 by connectors 40.
Each connector 40 also serves to prevent extrusion of the ring 14
and/or the sealing member 30 radially and horizontally between the
edges 35a of adjacent segments 35. Each connector 40 is secured to
one of the segments 36 by a screw or other fastener 41 which
extends into the threaded opening 36e. Each connector 40 is
connected to a pair of segments or anti-extrusion members 35
disposed above the segment 36 with which the connector 40 is
secured, by a slidable connection which includes lateral or
circumferential slots 40a in the connector 40 through which
connector screws or pins 42 are disposed. Each connector pin 42
extends into one of the openings 35d on the outer surface of one of
the segments 35, and each pin 42 has a head 42a which is larger
than the slot 40a so that the segments 35 are forced to move
radially with the segments 36 while permitting relative
circumferential movements of the members 35 with respect to the
member 36 with which it is connected, within the limits provided by
the length of the slots 40a.
In the operation or use of the blowout preventer B of FIGS. 1-6 of
this invention, the normal undistorted shape of the sealing member
30 is illustrated in FIG. 1 and in that position, the segments 35
are circumferentially spaced from each other so that there is a
space between the sides 35a of the adjacent segments 35. The
segments 36 below the segments 35 cover the gap thus present
between the edges 35a of the segments 35 and prevent extrusion of
rubber upwardly into the spaces between the segments 35. When it is
desired to seal with the pipe P or other object in the well bore,
hydraulic pressure or the like is introduced through the line 12b
to urge the annular piston 14 inwardly to thus force the sealing
element 30 into a smaller diameter and finally into sealing contact
with the external surface of the pipe P. During such inward
distortion of the sealing element 30 to its sealing position with
the pipe P, the segments 36 are carried with the rubber or other
material of the sealing element 30 and they thus move radially
inwardly to reduce the inner bore diameter of the inner surfaces
36b until they engage the pipe P. The connectors 40 urge the
segments 35 radially inwardly with the segments 36 and permit them
to move closer to each other to close the gap between their side
edges 35a until the surfaces 35b engage the pipe P also. It will be
understood that the surfaces 35b and 36b remain substantially
vertically aligned at all times and normally are also substantially
vertically aligned with the inner bore 30a of the sealing member or
element 30 so that extrustion of the sealing element 30
longitudinally of the pipe P is prevented by the overlapping
segments 35 and 36 at all times.
The lower anti-extension means M' has segments 35' and 36' which
correspond with the segments 35 and 36 and they are connected
together by connectors 40' in the same manner as the connectors 40
serve to connect the segments 35 and 36 as previously explained.
The lower anti-extrusion means M' functions in the same manner as
the upper anti-extrusion means M and both work simultaneously above
and below the sealing element 30 to thus confine the sealing
element 30 against extrusion in either longitudinal direction with
respect to the pipe P.
When it is desired to retract the blowout preventer B from its
sealing position (FIG. 2) to its open or retracted position (FIG.
1) the pressure in the recess 12a is relieved through the relief
line 15b or other suitable means so that the annular piston 14
returns to its normal undistorted condition by its own inherent
resiliency or other suitable means. Likewise, the sealing element
30 returns to its normal undistorted position of FIG. 1, carrying
with it the segments 36 and 36', which through connectors 40 and
pins 42 carry with them the segments 35 and 35', respectively, so
that they move to their fully open position (FIGS. 1 and 3).
In the modified form of this invention illustrated in FIGS. 7-9, a
blowout preventer B-1 of the ram type is illustrated, utilizing the
same anti-extrusion means M and M' and modified only to accommodate
the semi-cylindrical configuration of the rams R of the blowout
preventer B-1 rather than annular shape of the preventer B.
The blowout preventer B-1 has a housing H-1 of any suitable
construction which is adapted to be connected in a stack of blowout
preventers or in a string of well casing or pipe in the
conventional manner. Thus, the housing H-1 has a longitudinal
central bore 50 therethrough for the passage of the pipe P or other
well tools in the known manner. The housing H-1 also has upper and
lower flanges 51 with bolt openings 51a or other suitable means for
connecting the preventer B-1 in the stack of the preventers or in
the well casing. The rams R are adapted to fit within lateral
recesses 50a in the housing H which communicate with the
longitudinal bore 50 in the known manner.
A conventional head or bonnet 52 is connected to each side of the
housing H, and each of such heads or bonnets 52 has a recess 52a
(one of which is shown in FIG. 7) and each of which is aligned with
the lateral openings 50a in the housing H-1, so as to form a
continuation thereof. The rams R are received in their respective
recesses 52a when they are in the retracted position (FIG. 8). A
piston rod 54 extends through a suitable seal 52b in the bonnet 52
and is connected to a piston 56 disposed in the cylinder 57 in the
known manner. The cylinder 57 is closed by a cap 58 having a fluid
inlet line 58a therewith for the introduction of hydraulic fluid or
other fluid for operating the piston 56. Another fluid line 52c is
provided for communicating with the opposite side of the piston 56
for introducing hydraulic fluid or other fluid to move the piston
56 to the right or outwardly from the position shown in FIG. 7. It
will be understood that the piston 56 is merely exemplary of any
suitable power means for moving the rams R, and a similar power
means is provided for each of the rams R, although only the piston
56 is illustrated for the right-hand ram R in FIG. 7.
To facilitate the description, the details of only one of the rams
R will be described hereinafter, and only wnen it is necessary to
show the interaction of the two rams will the other ram be
specifically identified. However, it will be understood that the
two rams R are preferably made in the same manner and bear like
numerals and/or letters for identification purposes.
Thus, each ram R has a ram carrier 60 which is connected to the
piston rod or stem 54 preferably in the conventional releasable
manner, utilizing a button 54a on the rod 54 fitting into a
suitable slot in the ram carrier 60. The ram carrier 60 is
preferably formed of steel or other relatively rigid material and
is substantially semi-cylindrical in cross-sectional shape (FIG.
8). The ram carrier 60 is provided with an internal recess or
surface 60a which is likewise substantially semi-cylindrical in
cross-sectional shape and which is adapted to receive a seal
element 61 formed or rubber or other suitable resilient material
and preferably having an external convex surface 61a which
substantially conforms with the internal surface of the recess 60a
(FIG. 8). Side anti-extrusion plates 62 formed of steel or other
metal are disposed so as to engage the inside surface of an
inwardly extending lip 50b on the housing H-1. During movement of
the carrier 60 from the position of FIG. 8 to the stop position of
FIG. 7, there is a sliding movement between the carrier 60 and the
side plates 62 as the seal element 61 deforms and urges the
semi-cylindrical sealing member S into sealing contact with the
pipe P.
The seal member 61 is confined at its upper end between the ram
carrier 60 and an upper ram confining and alignment plate 64 which
is also preferably semi-cylindrical (FIG. 1) which plate 64 is
secured to the carrier 60 by one or more cap screws 66 or other
suitable securing means. It is to be noted that the upper surface
60b of the ram carrier 60 engages and slides relative to the upper
surface of the recess 50a and the recess 52a. The upper surface 61b
of the seal member 61 engages and seals with the upper surface of
the recess 50a.
Each ram R also has a lower ram confining and alignment plate 65
which preferably extends for the full depth of the ram and which is
provided with a shoulder 65a or other suitable engaging means for
enabling the carrier 60 to retract the plate 65 outwardly therewith
but permitting inward movement of the carrier 60 relative to the
plate 65 after inward movement of the plate 65 is stopped by
engagement with the opposite plate 65 on the other ram R.
It is to be noted that the vertical or longitudinal area between
the upper alignment plate 64 and the lower alignment plate 65, and
inwardly of the seal member 61, forms a pocket or recess which is
generally semi-cylindrical for receiving the parts of the ram R
which are normally the primary replaceable parts. Such parts may be
preassembled and inserted initially into position as will be more
evident hereinafter.
Also, replacement assemblies including such parts may be used when
necessary.
Such replaceable assembly of the ram R includes the yieldable
sealing element or member S formed of rubber or other similar
resilient yieldable material. The upper anti-extrusion means M
shown in FIGS. 7-9 is provided above the sealing element S for each
of the rams R and likewise, the lower anti-extrusion means M' is
provided below the sealing element S for each of the rams R.
As best seen in FIG. 9, the anti-extrusion means M for each ram R
includes the segments or anti-extrusion members 35 and 36 which are
disposed in the two layers in the same manner as described
heretofore in connection with FIGS. 1-6, the only difference being
that the segments 35 are arranged in a semi-circular or
semi-cylindrical form when used with the rams R of FIGS. 7 and 8.
It should also be noted that the end segments 135 in the upper
anti-extrusion means M for each ram R are modified so as to be only
partial segments as compared to the other segments 35 so that the
semi-cylindrical configuration is obtained for the entire assembly
of the segments 35 (FIG. 9). The segments 35 and 36 as well as the
special segments 135 are connected together by the same connectors
40 and the connector screws 41 and pins 42 as heretofore described
in connection with FIGS. 1-6. The construction of the lower
anti-extrusion means M' for each ram R is identical to that
heretofore described for the anti-extrusion means M, except that
they are upside down with respect to each other as is evident from
FIG. 7.
In the operation or use of the form of the invention shown in FIGS.
7-9, the rams R are operated in the conventional manner, utilizing
hydraulic pressure supplied to the line 58a for moving the piston
56 for each ram R inwardly from the open or retracted position
(FIG. 8) to the inner or sealing position (FIG. 7). When the rams
contact each other at the radial surfaces 64a and 65a, the inward
momvement of the confining plates 64 and 65 is prevented, but the
carrier can still exert an inward radial force on the seal member
61 and the sealing element S for each of the rams R. Such
distortion of the sealing member S continues until it is in full
sealing contact with the external surface of the pipe P.
During the inward radial movement or distortion of the sealing
element S, the segments 36 and 36' are moved with the material of
the sealing element S radially inwardly so as to constantly
maintain a metallic barrier to prevent longitudinal extrusion of
the flexible material of the sealing element S. The extrusion
members 35 move with the elements S by reason of the connectors 40
and likewise the segments 35' move with the segments 36' by reason
of the connectors 40' so as to avoid any extrusion of the rubber or
other material of the sealing element S between the segments 36 and
36', respectively. Ultimately, the segments of the extrusion means
M and M' also contact the external surface of the pipe P and thus
block longitudinal extrusion of the sealing element S in either
longitudinal direction relative to the pipe P. Upon a release of
the pressure acting on the piston 56 and the application of
pressure to move same outwardly for each of the rams R, the rams R
are retracted and are moved to the position of FIG. 8 so as to
provide the full open bore corresponding to the bore 50 of the
housing H-1 in the known manner.
Instead of the dished out or concave surface 30a, the shape of the
surface 30a or other portions of the sealing member 30 may be
modified, or recesses or the like in the member 30 may be provided,
the purpose of which is to compensate, or partially compensate, for
the smaller volume of the space available for the rubber of the
member 30 when it is in its sealing position (FIG. 2) as compared
to the volume of the space available for such member 30 in its
retracted position (FIG. 1).
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape, and materials as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *