Note: Descriptions are shown in the official language in which they were submitted.
CA 0221018~ 1997-07-10
SPLITTING APPARATUS FOR SPLITTING COILS OF METAL
SUCH AS STEEL AND ALUMINUM AND COILS OF OTHER
MATERIALS INTO STRIPS
BACKGROUND OF THE l~V~NlION
1. Field of the Invention:
This invention relates to a cutter assembly or cutter
assembling means for ~litting of material coils or strips of
relatively large width to either one strip of desired width
or to several strips.
2. Background Information:
The strip for slitting is preferably made of metal, for
example steel or aluminum, but strips of other material can
be used. The invention is useful for strong and thick
material but can also be used for weak and soft material.
Slitting of coils of large width to one or several
coils of desired width, often in connection with edge
cutting, is favorably performed in a cutter assembling means.
Such means are described for instance in U.S. Patent No.
4,183,273 and European Patent No. 0 444 047 Bl. The strip
is directed in between two arbors equipped with dish or disc
shaped cutters and spacers. The arbors are mutually parallel
disposed above each other and joined in bearings to two
frame portions. In other words, the two arbors are disposed
mutually parallel to one another and are positioned one
above the other. In one end of the a is a driving
means for rotating the arbors.
OBJECT OF THE l~v~NlION
It is preferable to be able to have the other end of
the arbors free. In this way it will be very easy
reassembling and assembling the cutters and spacers when
changing the material for slitting and/or changing the width
of the desired strips. The sets of cutters and spacers are,
when reassembled, pushed over to other arbors, and then
docked to the ends of the arbors on the slitter. In the
same way new sets of cutters and spacers are pushed over to
the arbors of the slitter.
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SUMMARY OF THE lNv~ ION
The present invention teaches that, to free the ends of
the arbors, one of the frame portions is disposed to revolve
sideways around a vertical shaft. But this assembly is
often too weak. When slitting there will sometimes be forces
5 that are not directed in an imaginary plane through the
longitll~; n~l center lines of the two arbors. These forces
will tilt the movable frame portion. The slitting operation
will therefore not be sufficiently good.
In other words, one portion of the frame can be disposed
in a rotatable manner, substantially transverse to a vertical
shaft. In this configuration, it is possible that forces
generated during the slitting process will tilt the movable
frame position away from the desired position, resulting in
a product that is not within acceptable tolerances.
Sets of cutters and spacers are fixed to the arbors in
that a hydraulic piston, adapted on the movable frame
portion, force the sets against a fixed ring round the
periphery in the end of the arbor. That will naturally
cause, that the cooperating frame portions will be bent away
from each other and the forces on the trust or thrust
bearings, placed on the frame portion, will increase. The
best way is preferably to keep the forces within the arbors
in question-
Stated another way, different sets of cutters andspacers are affixed to the arbors in a manner so that when
the arbors assume a certain position, the sets of cutters
and spacers are forced against a fixed ring, which fixed
ring is set around the periphery of an end of the arbor.
The connecting assembly within the movable arbor contains a
piston which presses a thrust ring toward the fixed ring.
A~ a result, the portions of the frame will be forced away
from each other and the forces on the thrust bearings will
increase.
When slitting, where you carry out even numbers of
cuts, the axial forces will be in balance. But by uneven
cuts it will be forces, that are not in balance. In this
situation, wherein there are uneven numbers of cuts, axial
forces will increase in the thrust bearings of the arbors.
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When slitting, the deflection of the arbors may not be
allowed to be too big. In other words, the deflections of
the arbors must be kept within certain tolerances during the
slitting process. In that case, or the case when the
5 deflection of the arbors exceeds the tolerances, the edges
of the strips will not be sufficiently good or of sufficient
quality, especially depending on that the plane surfaces of
the cutters will be obliquely or obtusely angled in relation
to each other. In other words, the edges of the strips may
not be of an acceptable quality if the plane surfaces of the
cutters are obliquely angled with respect to one another.
That can also cause the edges to graze against each other,
in which case, the edges will likely be damaged.
By common mounting of bearings on the arbors it is
generally believed, that the arbors will be, from the bending
point of view, freely fitted to the frame portions. If you
were able to fit the arbors in the frame portions in that
way that you could find them really fixed from the bending
point of view, the bending of the arbors will decrease to
one fifth.
To get an acceptable overlaying of the cutter edges
between the over and under arbors, the distance between the
respective cutter edges must be adjustable. The change of
distance will be performed by moving one or both of the
cooperating arbors vertically. Because of the resilience,
it will be difficult to adjust the distance and also keep
the correct distance between the respective arbors.
Surprisingly it has appeared a way to make a slitter
for strips and for sheets, where you are successfully able
to slit for instance stainless steel having a thickness of
up to 15 mm, also foils of aluminum having a thickness down
to 0.1 mm. The invention will be described more precisely
in the enclosed claims.
One aspect of the invention resides broadly in a slitter
for cutting strips of coils, said slitter comprising: a
frame; said frame comprising two portions; said two frame
portions being substantially parallel to one another; a
first arbor and a second arbor; two cutter sets, one of said
two cutter sets being disposed about said first arbor, and
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the other of said two cutter sets being disposed about said
second arbor; each of said two cutter sets comprising: at
least one cutter; and at least one spacer; said first and
second arbors being disposed between said two frame portions,
substantially transverse to said two frame portions; a drive
to rotate said first and second arbors; said drive being
disposed adjacent to one of said two frame portions; the
other of said two frame portions being movable with respect
to said first and second arbors; said first and second arbors
each having first and second ends; said first and second
arbors each comprising a cylindrical shaft disposed at said
first end of each of said first and second arbors; said
first and second arbors each comprising a fixed ring disposed
at said second end of each of said first and second arbors;
at least one assembly to connect one of said first and second
arbors to said movable frame portion; said at least one
connecting assembly comprising: a bearing assembly to connect
said one of said first and second arbors to said movable
frame portion; a first sleeve having first and second ends;
said first sleeve having an outside diameter; the outside
diameter of said first sleeve being greater at said first
end of said first sleeve than at said second end of said
first sleeve; said first sleeve for being disposed about
said cylindrical shaft of one of said first and second
arbors; said first end of said first sleeve being disposed
adjacent to said one of said first and second arbors; a
second sleeve having first and second ends; said second
sleeve being disposed about said first sleeve; said second
sleeve having an inside diameter; the inside diameter of
said second sleeve being greater at said first end than at
said second end; the inside diameter of said second sleeve
at said first end of said second sleeve being substantially
equal to the outside diameter of said first sleeve at said
first end of said first sleeve; the inside diameter of said
second sleeve at said second end of said second sleeve being
substantially equal to the outside diameter of said first
sleeve at said second end of said first sleeve; a collar
disposed about said first end of said second sleeve; a
thrust ring disposed adjacent to said collar; and said
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thrust ring being disposed and configured to tension said
cutter set between said thrust ring and said fixed ring.
The above discussed embodiments of the present invention
will be described further hereinbelow with reference to the
accompanying figures. When the word "invention" is used in
this specification, the word "invention" includes
"inventions", that is, the plural of "invention". By stating
"invention", the Applicants do not in any way admit that the
present application does not include more than one patentably
and non-obviously distinct invention, and maintains that
this application may include more than one patentably and
non-obviously distinct invention. The Applicants hereby
assert that the disclosure of this application may include
more than one invention, and, in the event that there i8
more than one invention, that these inventions may be
patentable and non-obvious one with respect to the other.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be disclosed in more details below
with reference to the accompanying drawings, wherein:
Fig. 1 is a side view of a slitter;
Fig. lA shows additional detail of the view shown in
Fig. 1; and
Fig. 2 is a longitudinal section through the bearing of
the arbors fixed to the movable frame portion.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The slitter, as shown in Fig. 1, is used where slitting
is executed between two arbors 2, 3. The arbors 2, 3 are
equipped with cutters 4 and intermediate spacers 5. The
width of the spacers 5 corresponds to the width of the
desired strips.
The arbors 2, 3 are fixed in the ends to two frame
portions 6, 7. The driving of these arbors 2, 3 is driven
by driving means contAi n; ng a driving unit 1, a gear
reduction set 8 and two universal driving shafts or Schmidt-
engagements 9 that are joined to the corresponding ends of
the arbors 2, 3. The driving unit 1 may be an electric
motor. In other words, the driving system for the arbors 2,
3 consists of the driving unit 1, connected to the gear
reduction set 8, with the two universal driving shafts 9
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connected to the ends of the arbors 2, 3. In one advantageous
embodiment, in order to get an extremely good stability the
two frame portions 6, 7 of the ~litter can be joined together
on the same base plate 11. One of the frame portions 6 will
be quite stiffly or rigidly fixed or affixed to the base
plate 11. The other frame portion 7 must be movable to
expose the non driven end 10 of the arbors 2, 3. Doing so
will make it relatively easy to change the sets of cutters 4
and spacers 5.
One movement is made in a direction parallel to the
center line of the arbors 2, 3 to lay the ends of the arbors
2, 3 quite free. The following movement is made
perpendicular to the previous movement. The movable frame
portion 7 is placed on two parallel guide rolls 13 that in
turn are fixed to the base plate 11. The two parallel roll
guides or rail guides 13 shall be mounted parallel to the
center lines of the arbors 2, 3 and in distance from each
other. To get increased stability it will be very good to
part or separate the roll guides 13 as much as possible.
The top parts of the rail guides 13 are fixed to the under
side of the frame portion 7. The play in the roll guides 13
and the friction is negligible. The top part 14 of the
guide roll is namely parted from the bottom part 15 by
spheres. The transverse movement is made in essentially the
same way. After the front portion 7 has been moved away
from its ordinary place or normal position to such an extent
that the ends of the arbors 2, 3 are quite free, the front
portion 7 has at the same time entered a sledge or sled 16,
which sled 16 is movable perpendicular to the previous
movement as far as it will be possible to dock a movable
carriage to the ends of the arbors 2, 3. The sled 16 is in
turn movable on rail guides 17 that are fixed to the bottom
plate 11.
Usually the change of sets 4, 5 will be made by help of
any kind of carriage. The carriage is movable in the
direction of the center lines of the arbors 2, 3. To the
carriage is fixed a vertical, turning post. To this post
are fixed in pairs above each other a number of arbors in
different directions. When changing of sets 4, 5 these must
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get free from or clear the arbors 2, 3. The movable frame
portion 7 is moved backwards and then sideways. The carriage
is docked to the free ends 10 of the arbors 2, 3. The sets
4, 5 can then be pushed over to the carriage. Another pair
of arbors, equipped with new sets 4, 5 are docked to the
~litter and pushed onto the arbors 2, 3.
Figure 2, described below, indicates greater detail of
the connection between the arbors 2, 3 and the moveable
frame portion.
Bringing the arbors 2, 3 together to the frame portions
6, 7 is aimed to get the play as small as possible both in
radial and axial direction. The best way is to use paired
bearings 18. The use of paired bearings 18 means that two
or more roller bearings are especially selected and tested
to work together very well and with small play. It will
also be favorable to increase bending resistance of the
arbors 2, 3, by hand clamping them to the bearing housings
24. That will be done by not allowing any bending inside
the bearing housing 24. Practically it will be made by
using at least two paired bearings 18 side by side. By
extremely bad circumstances it is a favor to part them away
a distance of at least one width of the used bearings 18.
From this point of view and of other circumstances as will
be shown below, the shafts 12 may be cylindrical.
In other words in case of extremely poor conditions, it
is preferable to part or separate the bearings 18 by about
one width of one of the bearings 18.
By providing pairs of bearings 18 on opposite sides of
the shaft 12, which bearings are separated by a small space,
the invention can provide a more stable arrangement with
regard to motion transverse to the axial direction. In
other words, the shaft will be less inclined to wobble around
the axis.
The vertical position of at least one of the arbors 2,
3 must be adjustable to adjust for the overlapping of the
edges. The bearing housings 24 of the adjustable arbors 2,
3 are guided by guides in the oblong windows of the frame
portions 6, 7. Vertical rail guides are fitted to the
vertical insides of the windows. The vertical position will
CA 0221018~ 1997-07-10
continuously be adjusted by hydraulic jacks below the bearing
housings 24. The hydraulic jacks get the hydraulic power
from a servomotor, which servomotor is adjusted by a micro-
computer, getting impulses from level indicators.
Figure lA, depicts schematically a level indication
system to track the position of the arbors 2, 3 relative to
the bottom plate 11. Connected to the level indicator is a
computer control system to process the information received
from the level indication system. The computer control then
connects to a servomotor, also ~hown schematically, which
servomotor then adjusts the vertical position of the arbors
2, 3.
It is very important to make all parts of the slitter
very stiff or firm or rigid. For this reason it is favorable
to use rail guide~ mounted at the four vertical edqes of the
oblong window.
The set 4, 5 is fit to the arbor 2, 3, between a fixed
ring 19 and a movable hydraulic trust or thrust ring 20.
The fixed ring 19 is seated at the driving end 9 of the
arbor 2, 3.
The thrust ring 20 is axially movable and is similar to
the outer cylinder of a jack. The piston 21 of the jack is
movable compared to or in relation to the thrust ring 20.
The piston 21 is a part of a collar 22 on a moreover or
substantially cylindric sleeve 23. The sleeve 23 is movable
and located on a hollow arbor 25 on the shaft 12 of the
arbor 2, 3.
The roller bearings 18 are fit to the mantle of the
sleeve 23. The bearings 18 are joined to the movable frame
portion 7 by bearing housings. A hollow arbor 25 is located
between the sleeve 23 and the cylindrical shaft 12 of the
arbor 2, 3. The hollow arbor 25 can be considered to be a
sleeve with an end part 26 in the gable side. In this part
26 is located a hydraulic piston or hydraulic chamber 27.
In the center of the hollow arbor 25 is a centric or central
cavity. The bore diameter shall with slip fit match the
diameter of the shaft 12. In other words, the bore diameter
iB substantially the same as the diameter of the shaft 12,
with just enough variance in diameters to allow a slip fit
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of the shaft 12 in the bore. The outer surface of the hollow
arbor 25 is tapered to a smaller diameter in the end part
26. The inner surface of the sleeve 23 is adjusted to be in
contact to the outer surface of the hollow arbor 25 but to
also allow some pushing up on the hollow arbor 25. The
pushing up of the sleeve 25 is limited to the piston stroke
of the hydraulic piston 27 or of a fixed lip. The pushing
up movement will also initiate a force between the shaft 12
and the sleeve 23. The location of bearings 18 will also be
at relatively the same place on the arbor 2, 3.
From the end part 26 of the hollow arbor 25 are drilled
three holes 29, 30, 31 in axial directions. The first one
29 leads to the thrust ring 20. The first hole 29 is also
connected to a spring-loaded accumulator (not shown) to
prevent fall of pressure depending on leakage. The second
hole 30 is connected to ring-shaped cut-in portions 32 in
the inner surface of the piston 27 located at the end part
26 of the hollow arbor 25.
All three holes 29, 30, 31 are also separately connected
to a turnable or rotatable or movable hydraulic oil connection
33. The hydraulic oil is led to this connection from a
force pump (not shown) by a flexible tube 34.
In this way the clamping of the set 4,5 is kept within
the arbor 2, 3 and essentially no influence on the axial
bearing occurs.
Another advantage of this process to fix connect the
arbors 2, 3 to the bearing housings 24 and to fix connect
the bearing housings 24 to the frame portions 6, 7, is that
it builds up a very stiff frame structure of the arbors 2,
3, the frame portion and the base plate 11.
In one embodiment of the present invention, the slitter
is placed in operating position by applying hydraulic oil
through the axial hole 29. The hydraulic oil then flows
into the piston or hydraulic chamber 21 and forces the thrust
ring 20 toward the fixed ring 19. This holds the cutters 4
and spacers 5 in the correct place. During operation, the
hollow arbor 25 and the sleeve 23 are slip fit onto one
another and held by pressure in the hydraulic piston or
piston chamber 27. Due to the design of the end part 26 and
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the outer sleeve 23, the pressure in the piston chamber 27
pushes the outer sleeve 23 over the hollow arbor 25 and then
pushes the assembly of outer sleeve 23 and hollow arbor 25
onto the cylindrical shaft 12.
It is advisable to make the change of the sets 4, 5 in
the following way:
1. The hydraulic pressure to the thrust ring 20 (which
is normally pressurized) is discharged to essentially zero.
2. The hydraulic pressure to the hydraulic piston 27
is increased a little to block the sleeve 23 up on the shaft
12.
3. The hydraulic pressure is increased to the cut-in
portions 32 to get an oil film between the hollow piston 25
and the sleeve 23.
4. The pressure in the hydraulic piston 27 is gradually
reduced until the sleeve 23 is loose from the hollow arbor
25. The hydraulic pressure to the oil connection 33 is
unloaded.
The movable frame portion 7 is now free to be moved
backward and sideways. The sets 4, 5 are now also free to
be moved backward and away from the arbors 2, 3.
New sets 4, 5 can now be pushed onto the arbors 2, 3.
Stated another way, the method of disassembly involves
first discharging the hydraulic pressure to the piston 21 to
release the pressure on the thrust ring 20. Following this
release of pressure, the pressure to the piston chamber 27,
is increased slightly, by increasing the supply of hydraulic
oil to the piston 27 through the hole or passage 31. This
application of pressure will force the sleeve 23 to move
toward the arbors 2, 3.
Following the pressurization of the piston 27, additional
hydraulic oil can also be supplied through the hole 30 to
the cut-in portions 32. Hydraulic oil supplied to the cut-in
portions 32 will then go through the cut-in portion 32 to
form a thin film between the hollow arbor 25 and the sleeve
23. This can allow the hollow arbor 25 and the sleeve 23 to
be movable with respect to one another. In other words, the
integrity of the slip fit between the hollow arbor 25 and
the sleeve 23 will be decreased.
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Once this 81ip fit has been weakened, the hydraulic oil
supply to the piston 27 can be decreased, until the sleeve
23 becomes loose or free with respect to the hollow arbor
25. At this time, the movable frame portion 7 can be moved
away from the arbors 2, 3 and the cutters 4 and spacer~ 5
can be changed.
The reassembly of the slitting device can proceed as
follows:
5. The movable frame portion 7 is turned and put in
position .
6. The hydraulic pressure is increased in the cut-in
portions 32. An oil film will diverge between the hollow
arbor 25 and the sleeve 23.
7. The hydraulic pressure is increased in the hydraulic
piston 27 and the sleeve 23 is moved onto the hollow arbor
25.
8. The hydraulic pressure to the cut-in portions 32
will be unloaded. Now a stiff clamping will be obtained
between the sleeve 23 the hollow arbor 25 and the shaft 12.
In other words, the reassembly of the slitter involves,
first, returning the movable frame portion 7 to the operating
position. After this, hydraulic pressure is applied, through
hole 30, to the cut-in portions 32. This again allows an
oil film to form between the hollow arbor 25 and the sleeve
23. At this time, hydraulic pressure is again applied to
the piston chamber 27. By applying pressure to this piston
27, a force is applied to the hollow arbor 23 and a force in
the opposite direction is applied to the sleeve 25. This
again force fits the hollow arbor 25 and the sleeve 23
together.
Subsequent to the sleeve 25 and hollow arbor 23 being
forced together, hydraulic pressure is released to the cut-in
portions 32. This allows the oil film formed between the
sleeve 25 and the hollow arbor 23 to be forced out back
through the cut-in portion 32 and helps to secure the fit
between the sleeve 23 and the hollow arbor 25. At this
point, the sleeve 23, the hollow arbor 25 and the cylindrical
shaft 12 will be securely held together. Hydraulic oil can
CA 02210185 1997-07-10
again be applied to the piston 21 to secure the thrust ring
20 and the slitter can return to normal operation.
In one embodiment of the present invention, once the
fit between the sleeve 23 and the hollow arbor 25 has been
qecured, the sleeve 23 and hollow arbor 25 are fixed not
only with respect to one another, but also with respect to
the cylindrical shaft 12. In other words, the 81ip fit
connects not only the hollow arbor 25 and sleeve 23, but
also the shaft 12. This solid connection between the sleeve
23, the hollow arbor 25 and the shaft 12, minimizes forces
applied in the axial direction. This then means that a
minimal axial force, if any, will be applied to the bearings
18 and the bearing housings 24 where they connect to the
movable frame portion 7.
Similarly, during the removal process described above,
the release of the slip fit between the sleeve 23 and the
hollow arbor 25, also allow them to move relative to the
cylindrical shaft 12.
Following these steps, it is now possible to restart a
slitting operating.
All this above mentioned movements can be executed from
a central control panel or by a computer.
One feature of the invention resides broadly in the
slitter for strips, comprising two frame portions 6, 7 two
parallel arbors 2, 3 extending between the frame portions 6,
7, one of the frame portions 6 comprising driving means 1
for rotating the arbors 2, 3 the opposite frame portion 7
being movable to permit sets 4, 5 of cutters 4 and spacers 5
to be assembled and disassembled on each arbor 2, 3
characterized in that a hollow arbor 25, whose outside
diameter is a little tapered, is with slip fit pushed onto
the cylindrical shaft 12 of the arbor 2, 3 a sleeve 23 fit
with a collar 22, on the outside diameter have bearings for
joining the arbors 2, 3 to the movable frame portion 7 and
whose inner surface has the same tapering as the outer
surface of the hollow arbor 25 and by pressing it onto the
hollow arbor 25 will clamp it and at the same time clamp the
hollow arbor 25 with the shaft 12 of the arbor 2, 3 and a
movable hydraulic thrust ring 20, is fit to the collar 22
12
CA 0221018~ 1997-07-10
for pressing the sets 4, 5 of cutters 4 and spacers 5
together between this thrust ring 20 and a fixed ring 19 on
the opposite side of the arbor 2,3.
Another feature of the invention resides broadly in the
slitter characterized in that a hydraulic piston 27 is
centrally fit to the end part 26 of the hollow arbor 25 and
with hydraulic pressure i8 able to move the sleeve 23 onto
the hollow arbor 25.
Yet another feature of the invention resides broadly in
the a slitter characterized in that joining of the arbors 2,
3 to the frame portions 7 is made by help of at least two
paired bearings 18 side by side.
Still another feature of the invention resides broadly
in the slitter characterized in that the distance between
the bearings 18 is at least the axial width of the bearings
18.
A further feature of the invention resides broadly in
the slitter characterized in that the movable frame portion
7 is pushed away from the end shafts 12 of the arbors 2, 3
on at least two horizontal rail guides 13.
Another feature of the invention resides broadly in the
slitter characterized in that the movable frame portion 7 is
pushed sideways on other horizontal rail guides 17 after
that the frame portion has been moved quite away from the
ends of arbors 2, 3.
Yet another feature of the invention resides broadly in
the a slitter characterized in that the bearing housings 24
on the arbors 2, 3 are guided up and down by vertical guide
rails, fit to the two vertical opposite surfaces inside the
frame portions 6, 7 near the vertical edges of the surfaces.
Still another feature of the invention resides broadly
in the slitter characterized in that the vertical position
of the arbors 2,3 are continuously adjusted by hydraulic
jacks.
A further feature of the invention resides broadly in
the slitter characterized in that the hydraulic jack gets
power from a microcomputer adjustable servomotor that gets
impulses from level indicators.
CA 0221018~ 1997-07-10
The components disclosed in the various publications,
disclosed or incorporated by reference herein, may be used
in the embodiments of the present invention, as well as,
equivalents thereof.
The appended drawings in their entirety, including all
dimensions, proportions and/or shapes in at least one
embodiment of the invention, are accurate and to scale and
are hereby included by reference into this specification.
All, or substantially all, of the components and
methods of the various embodiments may be used with at least
one embodiment or all of the embodiments, if more than one
embo~ime~t is described herein.
Examples of arbors which may be used in embodiments of
the present invention may be found in the following U.S.
Patents: No. 5,383,263; No. 5,406,870; No. 5,427,482; No.
5,429,457; and No. 5,447,397.
Examples of devices for cutting metal strips which may
be used in conjunction with embodiments of the present
invention may be found in the following U.S. Patents: No.
5,406,865; and No. 5,433,563.
Examples of metal cutting blade which may be used in
conjunction with embodiments of the present invention may be
found in the following U.S. Patents: No. 5,381,342; No.
5,384,957; No. 5,402,693; No. 5,413,521; No. 5,417,132; No.
5,425,259; No. 5,438,819; and No. 5,464,164.
Examples of metal strips and devices for making metal
strips which may be used with embodiments of the present
invention, may be found in the following U.S. Patents: No.
5,379,829; No. 5,380,378; No. 5,381,342; No. 5,390,726; No.
5,394,722; No. 5,399,060; No. 5,409,653; No. 5,421,535; No.
5,425,259; No. 5,435,164; No. 5,437,089; No. 5,445,212; No.
5,447,802; No. 5,456,308; No. 5,461,770; No. 5,462,109; No.
5,468,914; No. 5,472,515; and No. 5,472,528.
Although only a few exemplary embodiments of this
invention have been described in detail above, those skilled
in the art will readily appreciate that many modifications
are possible in the exemplary embodiments without materially
departing from the novel teachings and advantages of this
invention. Accordingly, all such modifications are intended
14
CA 0221018~ 1997-07-10
to be included within the scope of this invention as defined
in the following claims. In the claims, means-plus-function
clause are intended to cover the structures described herein
as performing the recited function and not only structural
equivalents but also equivalent structures.
The invention as described hereinabove in the context
of the preferred embodiments is not to be taken as limited
to all of the provided details thereof, since modifications
and variations thereof may be made without departing from
lo the spirit and scope of the invention.
