U.S. patent application number 10/454401 was filed with the patent office on 2004-04-01 for chain with opposite plane links.
Invention is credited to Briscoe, Terry L..
Application Number | 20040060203 10/454401 |
Document ID | / |
Family ID | 29712029 |
Filed Date | 2004-04-01 |
United States Patent
Application |
20040060203 |
Kind Code |
A1 |
Briscoe, Terry L. |
April 1, 2004 |
Chain with opposite plane links
Abstract
A chain with opposite plane links is disclosed and may be
utilized in connection with an excavator or other heavy-duty
operation. Each opposite plane link includes two discrete loop
portions orthogonally-oriented with respect to each other. The
excavator may be, for example, a dragline excavating operation that
includes a drag rope and a dragline bucket. The opposite plane link
chain forms a portion of the drag system positioned adjacent to the
dragline bucket and secured to the dragline bucket. In operation,
the opposite plane link chain drags against the ground and
experiences wear. By rotating the opposite plane link chain and
reversing the ends of the opposite plane link chain, four discrete
wear surfaces are sequentially positioned to engage the ground.
Inventors: |
Briscoe, Terry L.;
(Portland, OR) |
Correspondence
Address: |
BANNER & WITCOFF
1001 G STREET N W
SUITE 1100
WASHINGTON
DC
20001
US
|
Family ID: |
29712029 |
Appl. No.: |
10/454401 |
Filed: |
June 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60384420 |
Jun 3, 2002 |
|
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Current U.S.
Class: |
37/307 |
Current CPC
Class: |
F16G 13/07 20130101;
F16G 15/12 20130101; F16G 13/12 20130101; E02F 3/58 20130101 |
Class at
Publication: |
037/307 |
International
Class: |
E02F 001/00 |
Claims
That which is claimed is:
1. A chain for a mining operation, the chain comprising a plurality
of interconnected links that each include a first aperture and a
second aperture, a plane of the first aperture being substantially
orthogonal to a plane of the second aperture, and each link being
formed as a rigid, one-piece member.
2. The chain recited in claim 1, wherein loops form the first and
second apertures, and a connector portion extends between the loops
and is integrally-formed with the loops.
3. The chain recited in claim 2, wherein the connector portion is
formed as a single rod member.
4. The chain recited in claim 1, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being approximately eight times the cross-sectional dimension.
5. The chain recited in claim 1, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being at least four times the cross-sectional dimension.
6. A chain for a dragline excavating operation, the chain
comprising a plurality of interconnected links, each said link
having a first end defined by a first closed loop, a second end
defined by a second closed loop, and a central connecting rod
interconnecting the first and second loops, the loops and the
connecting rod being integrally formed, and a plane of the first
loop being non-parallel to a plane of the second loop.
7. The chain recited in claim 6, wherein the plane of the first
loop is generally orthogonal to the plane of the second loop.
8. The chain recited in claim 6, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being approximately eight times the cross-sectional dimension.
9. The chain recited in claim 6, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being at least four times the cross-sectional dimension.
10. A dragline excavating operation comprising: a dragline bucket
for receiving excavated material; at least one line for supporting
the dragline bucket; and a chain secured to the dragline bucket,
the chain including a plurality of interconnected links, each said
link having a pair of closed end loops and a connecting portion,
each said loop lying generally in a plane, and the planes of the
loops being angled relative to each other.
11. The dragline excavating operation recited in claim 10, wherein
the planes of the loops are oriented orthogonally relative to each
other.
12. The dragline excavating operation recited in claim 10, wherein
the connecting portion for each said link is a single rod
member.
13. The dragline excavating operation recited in claim 10, wherein
the links each have a pitch and a cross-sectional dimension, the
pitch of each said link being approximately eight times the
cross-sectional dimension.
14. A chain for heavy-duty operations, the chain comprising a
plurality of interconnected links that each include: a first loop
that forms a first aperture; a second loop that forms a second
aperture, a plane of the first aperture being substantially
orthogonal to a plane of the second aperture; and a central
connecting rod positioned between the first and second loops,
wherein each of the first and second loops and the connecting rod
are one-piece members that are integrally-connected with each other
to form a rigid, one-piece structure for each link.
15. The chain recited in claim 14, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being approximately eight times the cross-sectional dimension.
16. The chain recited in claim 14, wherein the links each have a
pitch and a cross-sectional dimension, the pitch of each said link
being at least four times the cross-sectional dimension.
17. A method of operating a dragline excavating operation, the
method comprising steps of: securing a first end of a chain to a
dragline bucket, the chain having at least one link that defines a
first loop and a second loop for receiving loops of adjacent links,
a plane of the first loop being oriented orthogonally with respect
to a plane of the second loop; after a first side of the first loop
becomes worn from engaging the ground, disconnecting the chain from
the dragline bucket and rotating the chain 180 degrees about a
length thereof, and reconnecting the first end to the dragline
bucket to position a second side of the first loop in engagement
with the ground; after the second side of the first loop becomes
worn from engaging the ground, disconnecting the chain from the
dragline bucket, and connecting a second end of the chain to the
dragline bucket to position a first side of the second loop in
engagement with the ground; and after the first side of the second
loop becomes worn from engaging the ground, disconnecting the chain
from the dragline bucket and rotating the chain 180 degrees about
the length thereof, and reconnecting the second end to the dragline
bucket to position a second side of the second loop in engagement
with the ground.
18. A method of excavating comprising: supporting a dragline bucket
by at least one hoist line; coupling a chain to the dragline
bucket, the chain including a plurality of interconnected links,
each link including a first aperture and a second aperture, wherein
a plane of the first aperture is substantially orthogonal to a
plane of the second aperture; and operatively connecting the chain
to a drag mechanism and operating the drag mechanism to pull the
dragline bucket along the ground via the chain.
Description
CROSS-REFERENCE To RELATED APPLICATION
[0001] This application claims priority to a U.S. Provisional
Patent Application, which was filed in the U.S. Patent and
Trademark Office on Jun. 3, 2002 and accorded Serial No.
60/384,420.
FIELD OF THE INVENTION
[0002] The present invention relates to a chain with opposite plane
links and has application, for example, to mining equipment
utilized in a dragline excavating operation.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] In a mining operation that includes a dragline bucket,
excavation is accomplished by supporting and dragging the dragline
bucket along the ground through the use of drag chains and drag
ropes (e.g., cables). Examples of such mining operations, which are
referred to herein as dragline excavating operations, are disclosed
in U.S. Pat. No. 4,791,738 and U.S. Pat. No. 5,084,990 to Briscoe.
A pair of drag chains are secured to a front of the dragline bucket
to connect the dragline bucket to one or more pulling drag ropes
that are operated (i.e., lengthened or shortened) by a drag
mechanism. As the dragline bucket is pulled across the ground,
these drag chains also engage the ground in the excavation area.
The drag chains, therefore, experience significant wear as various
links of the drag chains slide against the ground. A conventional
chain for a dragline excavating operation includes a plurality of
links with a generally flat and oval configuration. Other chains
proposed for use in dragline excavating operations are disclosed in
U.S. Pat. No. 4,060,978 to McBain et al.; U.S. Pat. No. 6,170,248
to lanello et al.; and U.S. Pat. No. 3,181,257 to Larsen.
[0004] In accordance with the present invention, a chain for a
dragline excavating operation incorporates opposite plane links
that are each formed with first and second discrete loops angled
with respect to each other. In a preferred construction, the loops
of each link are orthogonal to one another. The opposite plane
links have a robust, strong construction and are preferably formed
as one-piece, rigid parts. The loops form apertures that are
preferably oriented orthogonally with respect to each other. Loops
of adjacent links extend through the apertures to interconnect a
plurality of links and form the chain. In addition to the loops,
each link also includes a connector portion that extends between
the loops and is formed integral with the loops. By using a single
connector portion between the loops, the length of each link can be
increased. For example, the pitch dimension of each link can be
twelve times the cross-sectional dimension of the link or more. The
use of such a single rod of metal as the connector portion, which
constitutes the majority of the length of each link, results in a
considerable weight savings as opposed to the conventional links
where opposite ends of each link are connected by a pair of metal
rod portions.
[0005] While chains with opposite plane links are not new per se,
they have not been previously used in connection with a dragline
excavating operation or other similar excavation operation within
an abrasive environment. Rather, such chains have found use in the
making of jewelry and other relatively light duty operations. See,
for example, U.S. Pat. No. 507,346 to Atwood and U.S. Pat. No.
2,807,929 to Gantz. As can be appreciated, these chains lack a
construction that could withstand the rigors encountered in a
dragline excavating operation. Furthermore, such chains have not
had a connector portion between the loops which increases the
overall length of each link and, by extension, decreases the total
weight of the strand of chain.
[0006] The use of the inventive opposite plane chain in a dragline
excavating operation provides a number of advantages that are
unknown in the prior art. These advantages include the following:
(1) The chain can be rotated four times for wear because,
regardless of the quantity of links, the end links are always in
opposite plane; (2) The center portion of each link is in the wear
shadow, therefore this section is lighter as it does not have to
contain wear metal for a high factor of safety; (3) Each link
changes the plane of the chain, therefore flexibility of the chain
is increased as each link acts as a double swivel;
[0007] (4) Better strength to weight ratio than flat and oval link
chain; (5) High wear metal in the bight area; and (6) Lighter
weight per foot than flat and oval link chain.
[0008] The advantages and features of novelty characterizing the
present invention are pointed out with particularity in the
appended claims. To gain an improved understanding of the
advantages and features of novelty, however, reference may be made
to the following descriptive matter and accompanying drawings that
describe and illustrate various embodiments and concepts related to
the invention.
DESCRIPTION OF THE DRAWINGS
[0009] The foregoing summary, as well as the following Detailed
Description of the Invention will be better understood when read in
conjunction with the accompanying drawings.
[0010] FIG. 1 is a perspective view of a dragline bucket and
rigging that incorporates a chain with opposite plane links in
accordance with the present invention.
[0011] FIG. 2 is a top plan view of a portion of the chain with
opposite plane links.
[0012] FIG. 3 is a side elevational view of the portion of the
chain with opposite plane links.
[0013] FIG. 4 is a perspective view of the portion of the chain
with opposite plane links.
[0014] FIG. 5 is a side elevational view of another portion of the
chain with an opposite plane link and a conventional link to
illustrate a difference in pitch length between the two types of
links.
[0015] FIG. 6 is a fragmentary view of the chain with opposite
plane links depicting another system for securing the chain with
opposite plane links to a dragline bucket.
DETAILED DESCRIPTION OF THE INVENTION
[0016] A dragline excavating operation may have a variety of
different constructions. As an example, a dragline excavating
operation may include a housing, a boom, a hoist rope, a dragline
bucket, and a drag rope. The hoist rope is controlled by a hoist
winch. Similarly, the drag rope is controlled by a drag winch,
which is utilized to decrease the effective length of the drag
rope, thereby pulling the dragline bucket across an excavation area
and filling the dragline bucket with earthen material to be removed
from the excavation area. The present invention is a chain in the
dragline excavating operation that has opposite plane links. The
present invention is not limited to this specific kind of system,
however, and the present invention can be used as the chain for
nearly any type of dragline excavating operation.
[0017] An example of a dragline bucket 50 and rigging that includes
a drag system 60 is depicted in FIG. 1. Dragline bucket 50 has a
pair of spaced vertical sides 52 and a rear wall 53 that extend
upward from a bottom surface 54 to form a generally scoop-shaped
structure for receiving the earthen material. A front end 55 of
dragline bucket 50 is open, and bottom surface 54 defines a
horizontal digging edge or lip to which a plurality of excavating
teeth 56 are attached.
[0018] A drag system 60 is secured to dragline bucket 50 and
includes a pair of drag ropes 62 (e.g., cables) and a pair of drag
chains 64, although other arrangements can be used. A pair of
connectors 58 extend forward from sides 52 to provide sites for
securing drag chains 64 to dragline bucket 50. A first end of each
drag rope 62 is secured to the drag winch, and a second end of each
drag rope 62 is secured to one of drag chains 64 at a connection
site 66. Similarly, a first end of each drag chain 64 is secured at
connection site 66, and a second end of each drag chain 64 is
secured to one of connectors 58 on dragline bucket 50. That is, the
forward sides of dragline bucket 50 are equipped with shackles,
which have generally vertical pins 59, to which drag chains 64
attach. As an alternate structure, a generally horizontal pin 59a
is depicted in FIG. 6.
[0019] Drag chains 64 are composed of a plurality of
interconnected, preferably identical opposite plane links. A
portion of one preferred construction of drag chains 64 is depicted
in FIGS. 2-4. Drag chains 64 each include a plurality of
interconnected links 70 that each have a first loop portion 72, a
second loop portion 74, and a connector portion 76 positioned
therebetween. Each first loop portion 72 and second loop portion 74
are generally circular or round in shape and define an aperture,
but could have other shapes. Connector portion 76 is
integrally-formed with each of first loop portion 72 and second
loop portion 74, and connector portion 76 extends between each of
first loop portion 72 and second loop portion 74. Accordingly, each
link 70 includes two loop portions 72 and 74 that form apertures
oriented orthogonally with respect to each other. Each first loop
portion 72 extends through the aperture formed by a second loop
portion 74 of an adjacent link 70. Similarly, each second loop
portion 74 extends through the aperture formed by a first loop
portion 72 of another adjacent link 70. In this manner, the various
links 70 are interconnected to form drag chains 64. Each link 70
may be formed through a casting or forging process such that first
loop portion 72, second loop portion 74, and connector portion 76
are one-piece members that are integrally-connected with each other
to form a rigid, one-piece structure for each link 70.
[0020] As depicted in the alternate configuration of FIG. 6, one of
links 70 may be directly secured to a connector 58a. Since links 70
each include loop portions 72 and 74 in different orthogonally
related planes, drag chain 64 can be attached directly to connector
58a and pin 59a to avoid the mounting rings or pear links that are
used in conventional systems to ensure that the conventional chains
can always be secured to the shackles irrespective of the
orientation of the final link. This elimination of a part also
provides weight reduction to the system. As can be appreciated,
each link 70 is substantially identical to eliminate the need for
the special end loop of the prior art. Instead, a bushing can be
provided in the usual opening. Similar considerations apply to
connector 58 and other connection systems.
[0021] In a conventional chain for dragline excavating operations,
each link has a generally planar configuration. More specifically,
the aperture or apertures that receive portions of adjacent links
are on a single plane. With reference to U.S. Pat. No. 4,060,978 to
McBain et al., for example, each link forms two apertures for
receiving portions of adjacent links, and the apertures are located
on a single plane. In each link 70, however, the aperture formed by
first loop portion 72 is oriented at approximately 90 degrees with
respect to the aperture formed by second loop portion 74.
Therefore, the planes of the apertures formed by first loop portion
72 and second loop portion 74 are substantially orthogonal to each
other. Although the orientation of the apertures preferably 90
degrees to each other, an orientation in the range of 60 degrees to
120 degrees, for example, may also be utilized in one or more links
70.
[0022] According to conventional thinking, in the conventional
chain that has the generally flat and oval link configuration, the
pitch (i.e., the distance from the inside surface at one rounded
end portion to the inside surface at the opposite rounded end
portion of the same link) of each link is approximately four times
the cross-sectional dimension (i.e., the thickness of one of the
two rods forming sides of the conventional chain) to provide
adequate strength. As an example, then, a link with a four inch
cross-section will generally have a sixteen inch pitch. In many
circumstances, tensile forces tend to elongate the link and draw
sides of the link together, thereby deforming the link to have the
general shape of a figure eight. In order to resist the
deformation, some links may incorporate a brace that extends
between opposite sides of the link, as in the McBain et al. patent
discussed above, which further adds to the weight of each link. The
tendency for the sides to draw together increases as the pitch of
the link increases in proportion to the cross-section. For this
reason, the pitch of many links with an oval configuration is
approximately limited to four times the cross-section. FIG. 5
depicts one of links 70 in combination with a generally
conventional link 80 to illustrate a difference in pitch length
between the two types of links.
[0023] In contrast to the conventional chains utilized in dragline
excavating operations, links 70 of the present invention may be
proportioned such that the pitch (i.e., the distance from the
inside surface at the end of first loop portion 72 to the inside
surface at the end of second loop portion 74 of the same link 70)
is most preferably approximately eight times the cross-section or
nominal diameter (i.e., the thickness of link 70 at connector
portion 76) of the chain. Accordingly, a link 70 that has a
cross-section of four inches may have a corresponding pitch of 32
inches, for example. Within the scope of the present invention,
however, the pitch may preferably range from four to twelve times
the cross section, but may have other relationships as well. The
use of orthogonal loops with a single connector rod does not suffer
the same failings as the conventional links described above.
[0024] The increased pitch to cross-section ratio discussed above
reduces the total number of links 70 that are utilized to form a
given length of each drag chain 64. Moreover, by using a connector
portion 76 that is formed as a single rod, instead of as two rods
in a conventional link, (1) the connector portion 76 may exhibit a
much smaller diameter than the sum of the two rod portions of the
conventional link; (2) a lesser amount of material is utilized to
form a given length of each drag chain 64; and (3) the overall
weight of each drag chain 64 is decreased. In comparing one
conventional chain for dragline excavating operations with a drag
chain 64 in accordance with the present invention that would be
designed for the same systems, drag chains 64 may be lighter and
yet provide comparable tensile strength and wear-resistance.
Advantageously, the lesser weight permits links 70 to be formed
with greater dimensions, thereby further increasing tensile
strength or wear-resistance, and/or dragline bucket 50 may have an
increased size. When drag chains 64 are sold with a dragline bucket
50, then the capacity of dragline bucket 50 can be increased to
take advantage of the reduced weight of drag chains 64. This
increased capacity provides increased productivity and decreased
cost to the dragline excavating operation. Alternately, drag chains
64 can be made more robust to provide longer wear life and less
down time to the dragline excavating operation, which also provides
a reduction in overall cost.
[0025] As discussed above, drag chains 64 may be lighter and yet
provide comparable tensile strength and wear-resistance. As an
example, the weight of the link in a conventional chain for
dragline excavating operations that has a 4 inch cross-section may
be approximately 239 pounds, whereas the weight of link 70 having
similar cross-sectional dimensions is 352 pounds. Two links of the
conventional chain have a length that is comparable to the pitch of
link 70. Accordingly, two links of the conventional chain weigh 36%
more than one link 70. Drag chains 64 provide, therefore,
significant weight savings in comparison to a similar length of the
conventional chain. Greater or lesser weight savings may be
realized in other systems with shorter or longer links. Moreover,
weight reduction benefits a dragline excavating operation because
the boom is constructed to excavate and haul a certain total weight
including the weight of the dragline bucket, rigging, and load
(i.e., the excavated material). A reduction in the weight of the
chains, such as drag chains 64, increases the amount of load that
can be gathered with each pass of the dragline bucket.
[0026] In pulling dragline bucket 50 across the excavation area,
links 70 of drag chains 64 will often slide along the ground.
Following repeated use, therefore, many of links 70 wear in areas
that contact the ground. In contrast with links of conventional
chains for dragline excavating operations with flat and oval links,
which have only two wear surfaces, each link 70 has four discrete
wear surfaces that include: a first wear surface 78a positioned on
a side of first loop portion 72; a second wear surface 78b
positioned on an opposite side of first loop portion 72; a third
wear surface 78c positioned on a side of second loop portion 74;
and a fourth wear surface 78d positioned on an opposite side of
second loop portion 74.
[0027] Drag chains 64 may be utilized such that each wear surface
78a-78d sequentially experiences wear during operation of the
dragline excavating operation. In other words, each drag chain 64
may be incorporated into the dragline excavating operation such
that first wear surface 78a initially contacts the ground and
slides against the ground as dragline bucket 50 repeatedly gathers
a load of earthen material. Once first wear surface 78a experiences
a relatively high degree of wear, the manner in which each drag
chain 64 is secured to dragline bucket 50 and drag ropes 62 may be
modified such that second wear surface 78b contacts the ground and
slides against the ground as dragline bucket 50 repeatedly receives
earthen material. Thereafter, third wear surface 78c and fourth
wear surface 78d are subsequently placed into position to contact
the ground and experience wear.
[0028] Drag chains 64 may be initially secured to dragline bucket
50 such that, for example, first wear surfaces 78a of links 70 face
downward toward the ground. Following repeated use of the dragline
excavating operation, drag chains 64 may be inspected to determine
the amount of wear experienced by first wear surfaces 78a. Once a
threshold amount of wear has occurred (i.e., after first wear
surfaces 78a become worn from engaging the ground), drag chains 64
may be disconnected from dragline bucket 50 and drag ropes 62 and
rotated 180 degrees about a length thereof. In other words, drag
chains 64 may be rotated such that second wear surfaces 78b of
links 70 face downward toward the ground. Following further use of
the dragline excavating operation, drag chains 64 may be inspected
once again to determine the amount of wear experienced by second
wear surfaces 78b. Once the threshold amount of wear has occurred,
drag chains 64 may be again disconnected from dragline bucket 50
and drag ropes 62. Rather than merely rotate drag chains 64 about
the length, drag chains 64 are rotated end over end such that the
ends that were secured to drag ropes 62 are now secured to dragline
bucket 50. In this way, the other links can be oriented to attach
to dragline bucket 50.
[0029] By reversing the positions of the ends of drag chains 64
with respect to drag ropes 62 and dragline bucket 50, drag chains
64 may be reconnected to dragline bucket 50 and drag ropes 62 such
that third wear surfaces 78c of links 70 face downward toward the
ground and the general process described above may be repeated.
That is, drag chains 64 may be disconnected from dragline bucket 50
and drag ropes 62 and rotated 180 degrees about the length thereof
once third wear surfaces 78c wear beyond the threshold amount,
thereby positioning fourth wear surfaces 78d to face downward
toward the ground. Once the threshold amount of wear occurs on
fourth wear surfaces 78d, drag chains 64 may be recycled.
Alternately, specific links 70 that are particularly worn may be
replaced or reinforced such that drag chains 64 may be utilized
again.
[0030] While a conventional chain for dragline excavating
operations also has four different wear surfaces (i.e., two on each
pair of adjacent links) each link does not include four different
wear surfaces. Further, since the elongated center connector
portion 76 of the present invention is recessed relative to the
outer loops, it typically does not engage the ground and experience
the same level of wearing. As a result, connector portion 76 need
not be as thick as the side portions of a conventional chain
because it does not slide against the abrasive ground surface.
Moreover, the contact surface is less in the inventive drag chain
64 to reduce the frictional drag loads caused by drag chains
64.
[0031] As discussed above, a conventional chain also has four
different wear surfaces, but each link does not include four
different wear surfaces, as in drag chains 64. The ability to
utilize the conventional chain in a manner that places each of the
four wear surfaces in contact with the ground depends primarily
upon the number of links in the conventional chain. If the
conventional chain has an odd number of links, then reversing the
conventional chain end over end will not change the wear surfaces
that contact the ground, whereas forming the conventional chain
with an even number of links permits a change in the wear surfaces.
In drag chains 64, however, the wear surfaces may be changed
regardless of the number of links in drag chains 64.
[0032] Drag chains 64 are disclosed above as being incorporated
into drag system 60. Chains having the configuration of drag chains
64 may, however, find application in other portions of the dragline
excavating operation. For example, FIG. 1 depicts conventional
flat, oval link chains as supporting dragline bucket 50. A chain
having the configuration of drag chains 64 may also be utilized to
support dragline bucket 50. In addition, a chain having the
configuration of drag chains 64 may be utilized in other types of
heavy-duty operations. For example, an opposite plane link chain
may be utilized as a chain for mooring ships or as a chain in a
conveying operation. Accordingly, a chain having opposite plane
links may be utilized in other portions of the dragline excavating
operation or for other heavy-duty operations.
[0033] The present invention is disclosed above and in the
accompanying drawings with reference to a variety of embodiments.
The purpose served by the disclosure, however, is to provide an
example of the various features and concepts related to the
invention, not to limit the scope of the invention. One skilled in
the relevant art will recognize that numerous variations and
modifications may be made to the embodiments described above
without departing from the scope of the present invention, as
defined by the appended claims.
* * * * *