U.S. patent number RE33,003 [Application Number 07/197,761] was granted by the patent office on 1989-08-01 for joint system.
This patent grant is currently assigned to Adolph Coors Company. Invention is credited to Larry M. Dugan.
United States Patent |
RE33,003 |
Dugan |
August 1, 1989 |
Joint system
Abstract
A joint for connecting a driving means to a driven means for
reciprocating movement wherein a confined deformable,
non-compressible material is in contact with a surface area of the
driving means and with a surface area of the driven means and when
a force is applied to the driving means to move the driving means
toward the driven means, the deformable, non-compressible material
deforms to compensate for any misalignment between the driving
means and the driven means until is reaches it non-compressible
state so that a uniform force is then transmitted across the
surface area of the driven means in one direction to move the
driven means.
Inventors: |
Dugan; Larry M. (Boulder,
CO) |
Assignee: |
Adolph Coors Company (Golden,
CO)
|
Family
ID: |
26893132 |
Appl.
No.: |
07/197,761 |
Filed: |
May 23, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
804628 |
Dec 5, 1985 |
04719845 |
Jan 19, 1988 |
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Current U.S.
Class: |
92/84; 92/170.1;
403/291; 403/360; 464/106; 277/434; 403/335; 403/377; 277/642;
277/644; 277/910; 277/944 |
Current CPC
Class: |
F04B
53/147 (20130101); F16J 1/12 (20130101); Y10T
403/54 (20150115); Y10T 403/7077 (20150115); F16B
2200/50 (20180801); Y10T 403/7037 (20150115) |
Current International
Class: |
F04B
53/14 (20060101); F04B 53/00 (20060101); F16J
1/10 (20060101); F16J 1/12 (20060101); F16J
001/10 (); F01B 011/02 (); F16B 007/10 () |
Field of
Search: |
;92/84,129,170,171,249
;277/188A ;74/110 ;464/87,92,106,147,158
;403/2,132,133,225,276,291,335,345,360,361,376,377 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Garrett; Robert E.
Assistant Examiner: Kapsalas; George
Attorney, Agent or Firm: Klaas & Law
Claims
What is claimed is:
1. Apparatus for increasing the working life of an oil well mud
pump having a ceramic cylinder liner wherein the force applied to
drive the piston operating in the ceramic cylinder lining is
relatively high and which piston is reciprocated at relatively high
rates with each stroke moving through a substantial distance
comprising:
a pump means for use as an oil well mud pump;
said pump means having a cylinder;
a ceramic cylinder liner secured to said cylinder;
a piston mounted for reciprocation in said ceramic cylinder liner
at relatively high rates with each stroke moving through a
substantial distance;
a piston rod having one end thereof fixedly connected to said
piston;
said piston rod having a longitudinal axis and an other end;
a cavity having a generally cylindrical inner surface and a
generally planar bottom surface formed in the other end of said
piston rod;
a solid, deformable, non-compressible material having a generally
cylindrical outer surface and generally planar end surfaces, which
are continuous in all directions, located in said cavity;
said solid, deformable, non-compressible material having a diameter
slightly less than but substantially equal to the diameter of said
inner surface of said cavity;
reciprocating driving means for applying forces to said piston rod
so as to reciprocate said piston rod and therefore said piston in
said ceramic cylinder liner;
said driving means having a longitudinal axis;
coupling means for connecting said driving means to said other end
of said piston rod so that reciprocal movement of said driving
means causes reciprocal movement of said piston rod;
said coupling means having a plug having a generally cylindrical
outer surface having a diameter slightly less than but
substantially equal to said diameter of said inner surface of said
cavity and having a generally planar end surface located in said
cavity and adapted to contact one of said generally planar end
surfaces of said solid, deformable, non-compressible material to
deform said solid, deformable, non-compressible material until it
reaches its non-compressible state so that said driving force from
said driving means is distributed evenly across said generally
planar bottom surface of said cavity of said piston rod, including
those instances wherein said longitudinal axes of said piston rod
and said driving means are not in alignment so as to move said
piston rod in one direction;
an annular recess formed in said outer surface of said plug and
said end surface of said plug;
retaining means in said annular recess for preventing extrusion of
said solid, deformable, non-compressible material out of said
cavity when a relatively high force is applied thereto by said
driving means; and
movement permitting means for permitting limited relative movement
between said plug and said solid, deformable, non-compressible
material so as to allow for the formation of a separation
therebetween.
2. Apparatus for increasing the working life of an oil well mud
pump having a ceramic cylinder liner wherein the force applied to
drive the piston operating in the ceramic cylinder lining is
relatively high and which piston is reciprocated at relatively high
rates with each stroke moving through a substantial distance
comprising:
a pump means for use as an oil well mud pump;
said pump means having a cylinder;
a ceramic cylinder liner secured to said cylinder;
a piston mounted for reciprocation in said ceramic cylinder liner
at relatively high rates with each stroke moving through a
substantial distance;
a piston rod having one end thereof fixedly connected to said
piston;
said piston rod having a longitudinal axis and an other end;
a cavity having a generally cylindrical inner surface and a
generally planar bottom surface formed in the other end of said
piston rod;
a solid, deformable, non-compressible material having a generally
cylindrical outer surface and generally planar end surfaces located
in said cavity;
said solid, deformable, non-compressible material having a diameter
slightly less than but substantially equal to the diameter of said
inner surface of said cavity;
reciprocating driving means for applying forces to said piston rod
so as to reciprocate said piston rod and therefore said piston in
said ceramic cylinder liner;
said driving means having a longitudinal axis;
coupling means for connecting said driving means to said other end
of said piston rod so that reciprocal movement of said driving
means causes reciprocal movement of said piston rod;
said coupling means having a plug having a generally cylindrical
outer surface having a diameter slightly less than but
substantially equal to said diameter of said inner surface of said
cavity and having a generally planar end surface located in said
cavity and adapted to contact one of said generally planar end
surfaces of said solid, deformable, non-compressible material to
deform said solid, deformable, non-compressible material until it
reaches its non-compressible state so that said driving force from
said driving means is distributed evenly across said generally
planar bottom surface of said cavity of said piston rod, including
those instances wherein said longitudinal axes of said piston rod
and said driving means are not in alignment so as to move said
piston rod in one direction;
an annular recess formed in said outer surface of said plug and
said end surface of said plug;
retaining means in said annular recess for preventing extrusion of
said solid, deformable, non-compressible material out of said
cavity when a relatively high force is applied thereto by said
driving means;
movement permitting means for permitting limited relative movement
between said plug and said solid, deformable, non-compressible
material comprising:
an annular recess formed in said coupling means and surrounding
said plug and having at least one cylindrical wall concentric with
and facing said generally cylindrical outer surface of said
plug;
said recess having a bottom wall located between said at least one
cylindrical wall and said generally cylindrical outer surface;
a flange formed on said other end of said piston rod and projecting
radially outwardly therefrom, said flange being located in said
recess; and
means for preventing removal of said flange from said recess.
3. Apparatus as in claim 2 wherein said means for preventing
removal of said flange from said recess comprises:
an annular slot formed in said at least one cylindrical wall of
said recess;
a retaining ring having a portion thereof seated in said annular
slot and a portion thereof extending into said recess; and
said portion extending into said recess having an inner diameter
less than the outer diameter of said flange and being located so as
to confine said flange in said recess.
4. Apparatus as in claim 3 wherein:
the distance between said retaining ring and said bottom wall of
said recess is greater than the thickness of said flange so as to
allow limited relative movement between said plug and said solid,
deformable, non-compressible material.
5. Apparatus as in claim 4 wherein:
said force is in excess of 80,000 pounds.
6. Apparatus as in claim 5 wherein:
said driving means and said driven means are reciprocated at rates
of at least 100 strokes per minute.
7. Apparatus as in claim 5 wherein:
said solid deformable, non-compressible material comprises
urethane.
8. Apparatus as in claim 5 and further comprising:
an annular recess in said outer surface of said solid, deformable,
non-compressible material. .Iadd.
9. Apparatus for increasing the working life of a pump having a
cylinder and a piston comprising:
a pump;
said pump having a cylinder;
a piston mounted for reciprocation in said cylinder;
a piston rod having one end thereof fixedly connected to said
piston;
said piston rod having a longitudinal axis and an other end;
a cavity having a generally cylindrical inner surface and a
generally planar bottom surface formed in said other end of said
piston rod;
a solid, deformable, non-compressible material having a generally
cylindrical outer surface and generally planar end surfaces, which
are continuous in all directions, located in said cavity;
said solid, deformable, non-compressible material having a diameter
slightly less than but substantially equal to the diameter of said
inner surface of said cavity;
reciprocating driving means for applying forces to said piston rod
so as to reciprocate said piston rod and therefore said piston in
said cylinder;
said driving means having a longitudinal axis;
coupling means for connecting said driving means to said other end
of said piston rod so that reciprocal movement of said driving
means causes reciprocal movement of said piston rod;
said coupling means having a plug having a generally cylindrical
outer surface having a diameter slightly less than but
substantially equal to said diameter of said inner surface of said
cavity and having a generally planar end surface located in said
cavity and adapted to contact one of said generally planar end
surfaces of said solid, deformable, non-compressible material to
deform said solid, deformable, non-compressible material until it
reaches its non-compressible state so that said driving force from
said driving means is distributed evenly across said generally
planar bottom surface of said cavity of said piston rod, including
those instances wherein said longitudinal axes of said piston rod
and said driving means are not in alignment so as to move said
piston rod in one direction;
an annular recess formed in said outer surface of said plug and
said end surface of said plug;
retaining means in said annular recess for preventing extrusion of
said solid, deformable non-compressible material out of said cavity
when a relatively high force is applied thereto by said driving
means; and
movement permitting means for permitting limited relative movement
between said plug and said solid, deformable, non-compressible
material so as to allow for the formation of a separation
therebetween..Iaddend. .Iadd.
10. Apparatus as in claim 9 wherein said movement permitting means
comprises:
an annular recess formed in said coupling means and surrounding
said plug and having at least one cylindrical wall concentric with
and facing said generally cylindrical outer surface of said
plug;
said recess having a bottom wall located between said at least one
cylindrical wall and said generally cylindrical outer surface;
a flange formed on said other end of said piston rod and projecting
radially outwardly therefrom;
said flange being located in said recess; and
means for preventing removal of said flange from said
recess..Iaddend. .Iadd.
11. Apparatus as in claim 10 wherein said means for preventing
removal of said flange from said recess comprises:
an annular slot formed in said at least one cylindrical wall of
said recess;
a retaining ring having a portion thereof seated in said annular
slot and a portion thereof extending into said recess; and
said portion extending into said recess having an inner diameter
less than the outer diameter of said flange and being located so as
to confine said flange in said recess..Iaddend. .Iadd.12. Apparatus
as in claim 11 wherein:
the distance between said retaining ring and said bottom wall of
said recess is greater than the thickness of said flange so as to
allow limited relative movement between said plug and said solid,
deformable, non-compressible material..Iaddend. .Iadd.13. Apparatus
as in claim 12 wherein:
said solid deformable, non-compressible material comprises
urethane..Iaddend. .Iadd.14. Apparatus as in claim 12 and further
comprising:
an annular recess in said outer surface of said solid, deformable,
non-compressible material..Iaddend.
Description
FIELD OF THE INVENTION
This invention relates generally to a joint for connecting two rods
together for reciprocation along aligned longitudinal axes and more
particularly to a joint for connecting two rods together for
reciprocation along aligned longitudinal axes and designed to
compensate for any misalignment while transmitting the
reciprocating forces particularly where large forces are
involved.
BACKGROUND OF THE INVENTION
In many types of equipment, such as in pumps, it is desirable to
reciprocate a piston through a cylinder to perform work. The piston
is connected to a piston rod which in turn is connected to a
cross-head rod by a suitable joint. The cross-rod is driven by a
motor driven crank and is mounted in guides so that it reciprocates
along a longitudinal axis. In such type of equipment, it is
essential that the piston runs true so as to avoid excessive wear.
This is particularly so where the cylinder of the equipment has a
ceramic liner. Pumps having ceramic cylinder liners have superior
abrasion and corrosion resistance compared to conventional metal
cylinder liners. However, even minor misalignment problems between
the ceramic cylinder liner and the pump's metal piston can cause
excessive abrasion of the ceramic cylinder liner and result in a
substantial reduction in the life of the ceramic cylinder liner.
The misalignment can result from angular offset between the
reciprocal axis of the piston rod relative to the cross-head rod or
lateral offset in that the reciprocal axis of the piston rod is
parallel to but laterally offset from the reciprocal axis of the
cross-head rod. One solution to this problem is set forth in U.S.
Pat. No. 2,639,172 to Leonard, Jr., wherein a cavity is formed
between one end of a piston rod and the associated end of a
cross-head rod. The cavity is filled with a fluid and is sealed by
a bellows. One of the problems associated with equipment disclosed
in Leonard, Jr., as set forth in column 4, lines 21-39, is that it
is not suitable for use in transmitting large forces. Also, the
structure in Leonard, Jr., is designed so that any misalignment
results in movement of the plunger.
BRIEF DESCRIPTION OF THE INVENTION
This invention provides a joint for connecting a driving means to a
driven means for reciprocating movement wherein a confined
deformable, non-compressible material is in contact with a surface
area of the driving means and with a surface area of the driven
means and when a force is applied to the driving means to move the
driving means toward the deformable, non-compressible material, it
deforms to compensate for any misalignment between the driving
means and the driven means until it reaches its non-compressible
state so that a uniform force in one direction is then transmitted
across the surface area of the driven means.
In a preferred embodiment of the invention, the driving means
comprises a cross-head rod connected to a suitable means so that
the cross-head rod is reciprocated along a longitudinal axis. The
driven means comprises a piston rod having a piston connected
thereto which piston is mounted for reciprocating movement in a
cylinder having a ceramic liner. The longitudinal axis of the
piston rod is in alignment with the longitudinal axis of the
cylinder. The piston rod is connected to the cross-head rod so that
movement of the cross-head rod moves the piston rod and therefore
the piston in the cylinder. The joint for connecting the cross-head
rod to the piston rod comprises a cylindrical cavity formed in one
end of the piston rod and a cylindrical plug formed on the
associated end of the cross-head rod. The plug has a diameter
slightly smaller than the diameter of the cavity so that the plug
may be inserted into the cavity and allow for slight axial and/or
lateral misalignment. A solid, deformable, non-compressible
material is located in the cavity and is in contact with a surface
area of the plug and with a surface area of the cavity. Means are
provided for preventing movement of the solid, deformable,
non-compressible material out of the cavity. When a force is
applied to the cross-head rod to move it toward the piston rod and
there is some degree of misalignment between the cross-head rod and
the piston rod, the cross-head rod will deform the solid,
deformable, non-compressible material until it reaches its
non-compressible state so that a uniform force in one direction
will be transmitted across the surface area of the cavity of the
piston rod. Thus, there will be no force tending to change the
alignment of the longitudinal axis of the piston rod with the
longitudinal axis of the cylinder.
In another embodiment of the invention, the piston is provided with
means to extend to life of the ceramic cylinder liner. In this
embodiment, the piston comprises a generally cylindrical metallic
base having a sealing means secured thereto. An annular recess is
formed in the metallic base adjacent to the sealing means. A ring,
formed from PEEK, is seated in the recess so as to provide a more
compatible material from the ceramic liner in the event of
excessive wear of the sealing means.
It is an object of this invention to provide a joint for connecting
a driving means to a driven means which joint compensates for any
misalignment between the driving means and the driven means so that
a uniform force in one direction will be applied across a surface
area of the driven means.
It is another object of this invention to provide means for
providing protection for a ceramic cylinder liner against excessive
abrasive forces.
Additional objects, advantages and novel features of the invention
are set forth in part in the description which follows which will
be understood by those skilled in the art upon examination of the
following or may be learned by practice of the invention. The
objects and advantages of the invention may be realized and
obtained by means of the instrumentalities and combinations
particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view with parts in section of one embodiment of this
invention;
FIG. 2 is an enlarged view of a portion of another embodiment of
this invention; and
FIG. 3 is an enlarged view of a portion of another embodiment of
the invention.
DETAILED DESCRIPTION OF THE INVENTION
In FIG. 1, there is illustrated the principal portions of one
embodiment of the invention described in this application. An end
portion 2 of a cross-head rod 4 has an end surface 6 and an annular
groove 8 spaced a short distance from the end surface 6. The
annular groove 8 has a perpendicular side wall 10 and a sloping
side wall 12. A member 14 has an opening 16 defined by a projecting
annular side wall 18. Means are provided for securing the member 14
to the end 2 of the cross-head rod 4. A split ring clamp 20 is
positioned in the annular groove 8 and has a sloping surface 22 in
contact with the sloping surface 12. The split ring clamp 20 has an
annular recess 24 having a sloping wall 26 and a perpendicular wall
28. A plurality of bolts 30 are threadedly mounted in the annular
side wall 18 and are provided with heads 32 having sloping
surfaces. As the bolts 30 are tightened, the sloping heads 32 will
act against the sloping surface 26 which will cause the sloping
surface 22 to act against the sloping surface 12 so as to pull the
surface 34 of the member 14 into contact with the end surface 6 of
the end portion 2 so as to secure the member 14 onto the end
portion 2 of the cross-head rod 4. An O-ring 36 seated in a recess
38 in the annular side wall 18 contacts a sloping surface 40 on the
end portion 2 to seal against contaminating materials. The
cross-head rod 4 is connected to suitable means (not shown) which
reciprocate the cross-head rod along the longitudinal axis 42.
An annular recess 44 is provided in the end surface 46 of the
member 14 and is defined by two spaced apart walls 48 and 50
extending generally in an axial direction and a wall 52 extending
generally in a radial direction. The portion of the member 14
inside of the wall 50 comprises a plug 54 for a purpose described
below.
An end portion 56 of a piston rod 58 has a cavity 60 defined by an
inner side wall 62 of a hollow annular projection 64. The cavity 60
has a bottom surface 66. A solid, deformable, non-compressible
material 68 is positioned in the cavity 60. In assembling the
joint, the annular projection 64 is inserted into the recess 44
until the surface 70 of the plug 54 is almost in contact with the
surface 72 of the solid, deformable, non-compressible material 68.
The annular projection 64 is retained in the recess 44 by a
retaining ring 74 seated in a groove 76 in the wall 48 and bearing
against a lip 78 on the annular projection 64. As illustrated in
FIG. 1, the distance between the retaining means 74 and the bottom
wall 52 of the recess .[.4.]. .Iadd.44 .Iaddend.is greater than the
thickness of the flange 77 having a lip 78 to allow limited
movement between the plug 54 and the solid, deformable,
non-compressible material 68. An O-ring 80 seated in a groove 82 in
the wall 48 is in sealing engagement with a wall 84 of the annular
projection 64 to seal against entry of contaminants. The plug 54 is
provided with an annular recess 86 in which is seated an O-ring 88
in sealing engagement with the walls of the recess 86 and the wall
62 of the cavity 60 to prevent movement of the solid, deformable,
non-compressible material 68 out of the cavity 60.
The other end 90 of the piston rod 58 terminates in a piston 92
having a generally cylindrical metallic base 94 and a sealing means
96 secured thereto. The sealing means 96 is in contact with the
inner wall 98 of a ceramic cylinder liner 100 which is mounted in
the cylinder 102 having a longitudinal axis 103. In the preferred
embodiment, the cylinder 102 is part of a pump. The piston rod 58
and the piston 92 reciprocate along the longitudinal axis 104. The
longitudinal axis 103 of the cylinder 102 and the ceramic cylinder
liner 100 is in alignment with the longitudinal axis 104 of the
piston rod 58 and piston 92.
In operation, a driving force is applied to the cross-head rod 4 by
suitable means, such as a motor (not shown), to move the cross-head
rod 4 toward the piston rod 56. The movement of the cross-head rod
4 moves the plug 54 into contact with the solid, deformable
non-compressible material 68. If there is any misalignment of the
longitudinal axis 42 of the cross-head rod 4 relative to the
longitudinal axis 104 of the piston rod 58, the surface 70 of the
plug 54 will be canted relative to the surface 66 of the piston rod
58. As the plug 54 moves into contact with the solid, deformable
non-compressible material 68, it will deform the solid, deformable,
non-compressible material 68 to fill whatever shape of space exists
between the surface 70 and the surface 66 until the solid,
deformable, non-compressible material 68 reaches its
non-compressible state. When the non-compressible state has been
reached, the driving force applied to the cross-head rod 4 will be
transmitted to the piston rod 58 uniformly and in one direction
across the surface area 66. The one direction will be parallel to
the longitudinal axis .[.58.]. .Iadd.104 .Iaddend.of the piston rod
.[.104.]. .Iadd.58.Iaddend.. Because of this operation, there will
be substantially no force tending to change the alignment of the
longitudinal axis of the piston rod with the longitudinal axis of
the cylinder.
In the embodiment of the invention illustrated in FIG. 2, the
annular surface 106 of the solid, deformable, non-compressible
material 68 is provided with a recess 108 so as to form a cavity
110 between the annular surface 106 and the side wall 62 of the
projection 64. With this cavity less force is required to deform
the solid, deformable, non-compressible material until it reaches
its non-compressible state so that the uniform force in one
direction will be applied to the surface area.
In FIG. 3, there is illustrated an embodiment of the invention
which provides for wear of the sealing material in the piston. In
the embodiment of the invention illustrated in FIG. 1, the metallic
base 94 is machined so that the outer side wall 112 is spaced an
absolute minimum distance from the inner wall 98 of the ceramic
liner 100. This construction is necessary so that the material in
the sealing means will not be able to extrude into any space
between the inner wall 98 and the outer side wall 112. When the
material in the sealing means wears, there is a tendency for a
portion of the metallic base 94 to come into contact with the inner
surface 98. This creates an abrasive force acting on the ceramic
liner 100 to substantially reduce the life of the ceramic liner
100. In the embodiment illustrated in FIG. 3, a recess 114 is
machined into the outer side wall 112 of the metallic base 94. An
annular ring 116 is seated in the recess 114 and is dimensioned so
that the outer surface 118 thereof is spaced an absolute minimum
distance from the inner surface 98 for the same purpose as
described above. The annular ring 116 is formed from PEEK which is
a polyester ether ketone. The PEEK material is substantially more
compatible with the ceramic liner than the metallic base material.
Therefore, when the material in the sealing means 96 wears, the
ceramic liner 100 will not deteriorate as rapidly so that the pump
may continue to operator for a substantial period of time.
In one embodiment of the invention, the joint is used in
association with an oil well mud pump having a ceramic cylinder
liner. The cross-head rod 4 is driven by a motor driven crank so
that the cross-head rod reciprocates along a longitudinal axis. A
member 14 is connected to the cross-head rod 4 and has a plug 54
having an effective diameter of about 4.5 inches. A piston rod 58
is connected to the member 14 through a flange 48 and has a cavity
66 having an effective diameter of about 4.5 inches. A generally
cylindrical urethane pad 68 is located in the cavity 66 and has an
effective diameter of about 4.5 inches and a thickness of about
0.44 inches. The piston rod 58 is connected to a piston 92 having a
metallic base 94 having an effective diameter of in the range from
about 4 to 7 inches. The sealing means 96 comprises rubber or
similar materials having an effective diameter of about 4 to 7
inches and a length of about 1.7 inches. A recess 114 is provided
in the metallic base 94 and has a length of about 0.5 inches and a
depth of about 0.12 inches. An annular ring 116, formed from PEEK,
is seated in the recess 114 and has an outer diameter of about 4 to
7 inches, a length of about 0.5 inches and a thickness of about
0.12 inches. A ceramic cylinder liner 100 having an inner
cylindrical surface having an effective diameter of about 4 to 7
inches is secured to the cylinder 102. The cross-head rod 4, piston
rod 58 and piston 92 are reciprocated at a rate of about 120
strokes per minute so as to have a stroke of about 10 to 12 inches
and a max cycle loading of about 112,000 pounds. The max force
applied to the surface 66 of the cavity 62 is about 7,000 psi. The
urethane pad 68 is capable of deforming to correct misalignment
problems wherein the angular misalignment of the longitudinal axes
of the cross-head rod to the piston rod is up to about 0.15 degrees
and the lateral misalignment is about 0.042 inches. It is
understood that the foregoing description of one embodiment of the
invention is for illustrative purposes only and that the invention
may be used in other environments and be constructed of different
operating parameters.
It is contemplated that the inventive concepts herein described may
be variously otherwise embodied and it is intended that the
appended claims be construed to include alternative embodiments of
the invention except insofar as limited by the prior art.
* * * * *