Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
goo5
~ACKG~UN~ OF THE IN~NTI_N
Numerous industrial mass production processes utilize
long coils of narrow width thin ga~e metal or alloy strip
material. For example, long coils of narrow width thin gage
copper alloy strip material frequently find use in the
electronics industry in con~inuous mass production of con-
tacts and in continuo~s for~.ation of connectors from moving
strip material. It is frequently required, therefore, to
provide long lengths of strip material of uniform geometry
which are adapted to readily pass through mass production
forming, stamping and assembling machinery.
In order to form such long coils of metal or alloy narrow
width thin gage strip material, it is necessary to join a
succession of lengths of strip material end to end and to
subsequently wind the continuously-ioined strip ma~erial onto a
large spool or storage reel. While the desire to quickly,
efficiently and economically carry cut such joining is
apparent, it nevertheless is essential that the ~oints between
strip segments be uniform with the remainder of the strip
material so that the stamping or other mass production
machinery utilized in forming contacts and other products can
operate without interruption and/or jamming due to cross-
sectional variations in strip cross section.
While the welding of thick strips, that is strips
~reater than about 0.012 in. gage, poses no particularly
excessive problem.s, the welding of narrow rridth thin ga~e
strip, that is strips less than about 0.012 in. gage, poses
several particularly troublesome problems. These problems
include burn-through of the strip material while welding,
explosion of the strip material, alignment and overlap
9005-~B
problerns associated with the hblding and heating of the
narrGw width thin strip material, and the need for expensiYe
welding equipment and/or welders possessing a high order of
skill for operating the equipment and carrying out the
welding processes.
Accordingly, it is the principal ob~ect of the present
invention to provide a process and means for rapidly, simply,
and efficiently joining a multiplicity of lengths of narrow
width thin gage strips end to end to form a substantial
continuous strip.
It is still a further object of the present invention
to provide a process for rapidly and efficiently joining a
muitiplicity of lengths of narrow width thin gage strips end
to end to form a substantial continuous strip which process
may be carried out by an inexperienced operator with a
minimum of training.
It is still a further object of the present invention to
provide a process for forming a continuous strip from a
plurality of narrow width thin gage strips which eliminates
the need for the use of expensive and/or complex apparatus in
carrying out the joining process.
Finally, it is yet a further ob~ect of the present
invention to provide a process and means for rapidly, simply,
and efficiently joining a multiplicity of lengths of narrow
width thin gage strips into a continuous strip whereby,
although the joints between the lengths of stri~ ma~erial
comprise or include a different material than the strip
segments, the Joints are of the same gage and geometry of
the continuous strlp elements, and are strong er.ough not to
break when placed on a TWR (transverse winding reel).
9005-liB
. ~
Further objects and advantages will appear hereinbelow.
P~IO~ ~T STA`TE~NT
It is known to form a continuous coil from thlck gage
strip, i.e. strip formed from materials greater than about
0.012 in. gage, by resistance butt welding a series of
relatively short length coils of strip and traverse winding
these onto a large spool. This butt welding process is time-
consuming and has frequently to be repeated to obtain a single
Joint. Adhesion is often marginal, and application of tension
and/or flexure to these joints often causes failure.
In thinner gage materials, that is strip material less
than about 0.012 in., resistance butt welding is generally not
useful since the application of welding current can cause
arcing and expulsion of molten metal and/or will, because of
the inability of the heated metal to support its own weight,
lead to folded or excessively overlapped joints. The 12tter
conditions are undesirable since in most cases the Joined
coils are often required to pass between dies whose clearance
is typically such that metal passing through the die cannot
vary by more than + 0.0005 in.
TIG welding has been used to successfully join narrow
width thin gage materials, but the capital outlay for this
t~-pe of equipment is high. An even greater problem and
limitation with this type of welding is that a relatively high
order of skill is required to achieve successful joints.
Uni~ed States Patent No. 3,421J676 to Jenkins et al.
discloses a process of joining thin metal sheets wherein end
portions of the sheets are cut, cleaned and held in butting
relation. After butting the sheets together, the joint is
sprayed with hot molten metal particles which are allowed to
9005~ 3
cool and solidify after which the joint is heated to proYide
a fused ~oint. The joining of the sheets is f~llowed by a
compressirg or planishing operation, preferably by planishing
roll means. Such a process when utilized for the ~oining of
narrow width thin gage metal st.ips suffers from several
Zrawbacks. Wnen thin sheets are placed in butting relatior,
they expand upon being heated, thereby causing foldover of
the joint or severe overlap at the ~oint. When it is attempted
to overcome such an overlap or foldover by compressing, severe
metal flow causes doglegging of the strip and requires exces-
sive effort ~nd time to overcome. In addition, spraying of
molten metal particles along the joint leads to an overlap of
material and high points across the area of the strips bridging
the ~oint which again requires excessive and time-consuming
wo~k to remove or reform in order to get the joint to the
same geometry of the strips. Finally, compression by plan-
ishing rolls tends to cause local inhomogeneity of deformation
which can result in "oil can" effects and doglegging of the
~oined strip.
The establishing of a predetermined gap between strip
ends prior to welding is shown in United States Patent Nos.
3,403,833 to Wheeler et al. and 3,771,215 to Williams et al.
The t 833 patent discloses a complex strip clamp assembly which
is utilized to establish a predetermined spacing between
trimmed ends of two strips to be joined. The '215 patent
- utilizes an indexing means in conjunction with a gauge bar
located at a welding station, the gauge bar and indexing
means ser~ing to establish a predete-rmined gap bet~een the
ends of the strips to be joined in the welding station.
Both these patents disclose complex and expensive spacing
5QC5--ilB
and weldin~ apparatuses, the need of which it is the purpose
of the present invention to obviate. In addition, neither
patent is directed specifically ro the joining of narrow
width thin gage strips, which as stated hereinabove, are not
economically and readily susceptible to welding operations.
The Metals Handbook, Volume 6 (T~elding ~nd Brazing) 3 8th
.
Edition, describes in part the cost benefits of ~lanual torch
brazing of parts and establishes typical joint clearances for
use with filler metals commonly employed in jGining copper
and copper alloys. ~hile such clearances might be of
importance in the jcining of certain metal parts, no con-
sideration has been given ro coefficients of expansion and
consequent joint o-~erlap or curling in the joining of strips
in end to end relation. Moreover, clearances which relate
to the filler metal utilized do not recognize considerations
and problems which relate to the joining of narrow width thin
gage strip material.
United States Patent Nos. 2,761,208 to ~itchell and
3,110,101 to Kieffer et al. disclose reducing welded joints
between joined strips by mechanical processing. The '208
patent teaches cold working an overlapped-welded joint,
preferably by drawing the joined strip through finishing
dies, while the 'lQl patent teaches high frequency hammering
of the welded junction between two strips consisting of a
metal selected from the group consisting of molybdenum,
tungsten and alloys thereof. Neither of these two patents
sol~Je any of the problems enumerated in the background section
hereinabove, and deal with a treatment of joints which
effects excessi~e metal deformation unsuitable for reduction
of joints in narrow width thin gage strip products.
9005-~B
~$~
The present.invention overcomes the deficiencies
described aboYe and pro~ides an efficient, speedy, and
economical process for joining narrow width thin gage metal
or alloy strips which can be carried out without the need for
expensive apparatus and/or highly skilled operators.
SU~MARY OF TH~ INVENTION
The process of this invention ~s unique in that butt
joining of narrow width thin gage strip material is accom-
plished via a brazing process which enables quick, efficient,
and inexpensive joining of the strip material into a
continuous coil of geometrically uniform narrow width thin
gage strip material.
In practicing the instant joining process, metal buildup
at ~oints is minima~ and joint strength has been found to be
approximately 80% that of the annealed parent metal strips.
Because of the heating required to braze the uoint, softening
of the strip occurs on either side of the brazed joint and
thus in flexing, the bending forces are not concentrated at
the brazed ~unction. In a further aspect of the present
invention, any excess braze metal present at the ~oint can
be readily reduced to the parent gage of the strip by a
specific hammering operation which takes into account the
fact that the braze metal is typically softer than the parent
metal.
In accordance with the present invention, cooperating
end portions of two n.~rrow width thin gage strip segments are
cut, aligned and held together with a predetermined gap
therebetween, and ~oined by a brazing operation forming a
~oint therebetween. The brazed ~oint is subsequently reduced
so as to have substantially the same geometric cross section
9005-.T~B
as the parent metal strip segments.
BRIEF_~ESCRIPTIO~ OF_THE DRAWINGS
Figures l(a) and l(b) are partial top and side views,
respectively, showing a finished brazed joint between two
narrow width thin gage s~rips joined together in accordance
with the process Gf this invention.
Figure 2 is a partial perspectiYe view of a guillotine-
type cutter adapted to carry out a strip cutting step in
accordance with this invention.
Figure 3 is a perspective view of a brazing fixture
adapted to carry out multiple strip segment gaging, holding,
and aligning steps in accordance with the process of the
present invention.
~ igure 4 is a partial side view illustrating another step
in the process of the present invention wherein a torch is
shown melting braze ma-terial placed in the joint between two
narrow width ~hin gage strips.
Figure 5 is a perspective view of a ha~mering device
utilized in hammering the joint area of two narrow width thin
gage strips to gage in accordance with another aspect of the
present invention.
~ igure 6 is a partial view in section of a completed
joint produced in accordance with the process of the present
invention.
Figures 7(a) and 7(b) are partial views, respectively, in
section of an undesirable brazed and hammered joint formed
when brazing of the joint is carried out on excessively over-
lapped narrow width thin gage strip end~ and excessive
hammering of the ~oint is required to reduce the joint to
parent metal or alloy gage.
7-
9005-MB
~$Z~
DETAILED DESCPIIPTION OF ~REF~R~ED EMBCDIMENT
While Yarious features of this invention are described
herein as being adaptable for joining of copper and copper
alloy narrow width thin gage strips, it is to be understood
that the various features of this ~nvention can be utilized
singly or in any combination thereof to join other metal and
alloy strip elements-as desired.
Figures l(a) and l(b) are top and bottom views showing
portions of a continuous narrow wi~th thin gage strip 1 made
up in part of strip segments 4 and 5. The strip segments 4
and 5 are joined together at a joint 7 via a brazing material
8. The joint 7 is shown to be of the same geometrical cross
section as that of the parent metal of strip segments 4 and
5. It is, of course, to be understood that any number of
strip segments may be ~oined end to end to make up a continuous
strip 1 of any desired length.
The term narrow width thin gage s~rip is used herein to
include any metal or alloy strip material which has a width
of about 3 in. or less and a thickness of about 0.012 in. or
less.
In one aspect of the present invention, the strip segments
~ and 5 have their respective ends 10 carefully cut or trimmed
so as to insure that the cut ends 11 (shown as dotted lines in
Figure 2) will match on subsequent brazing. Figure 2 depicts
one suitable apparatus for carrying out the strip segment end
preparation in accordance with the brazing process of the
present invention. In Figure 2, strip segments 4 and 5 are
aligned on base elements 12. To facilitate lateral alignment
of the strip segments 4 and 5, base elements 12 are provided
w th vertical guide walls 13. When an operator has placed the
gO O 5-~B
~$~7
strip ele~,ents 4 and 5 upon b~se elements' 12 in abutting
~elationship with guide walls _3,-he 'need merely activate
guillotine cutter 15 to shear off respective ends 10 and
~hereby assl~re that the now cut ends 11 of strip segments 4
and 5 match on subseauent brazing.
After providing cut ends''ll on strip segments 4 and 5,
the segments are aligned in abutting relationship with a pre-
determined gap therebetween for subsequent brazing of the
~oint 7. Figure 3 depicts a brazing fixture 20 particularly
suitable for alignment and securing of the strip segments 4
and 5 for subsequent brazing operations. Brazing fixt~re 20
is shown provided with alignment steps 22 having machined
faces 24 for providing alignment of the edges of strip
segments 4 and 5. Also secured to or forming part of the
brazing fixture is a pair of clamps 26. ~lamps 26 are
utilized to hold strip segments 4 and 5 via clamping screws 27
down on the upper surface 28 of anvils 29. The anvlls 29 are
machined so tnat the upper surfaces 28 thereof provide
effective alignment of the strip segments 4 and 5 in a single
plane at least in the area of the joint to be brazed.
Also mounted to the body of brazing fixture 20 is a
movable feeler gage 32. Feeler gage 32 is shown between the
cut ends 11 of strip segments 4 and 5 which abut flush
therewith, and is adapted via shaft 34 to be rotated out of
the Joint area during actual brazing operations.
Various modifications could, of course, be made to
holding fixture 20. For example, flat platens could be
provided at the tip of clamping screws 27 so as to prevent
dama~e to secured strip segments 4 and 5. Moreover, any of
a variety of clamping devices could be used, as for example
_g _ ,
9005-
$ ~ ~
spring activated, single action, and other types of clamps.
While anvils 29 might be constructed of various materials such as
for example transite, anvils constructed of a fired ceramic material such
as "Lava" manu~actured by 3M Company have been found to be more suitable
for use in conjunction with the process of the present invention, exhibi-
ting excellent wear characteristics while simultaneously functioning to
limit the heat transferred from the brazing zone.
A gap of approximately 9/16 in. between the anvil edges 30 has been
found to be quite suitable, being small enough to provide sufficient
support for the overhanging end portion of the strip segments 4 and 5
while at the same time being wide enough to permit the carrying out of
the gap setting and brazing steps of the present invention.
Figure 4 shows the use of a torch 36 to apply heat to a brazing
paste or material 8 located in the joint between the two strip segments 4
and 5~ It has been found that for some alloys and gages, such as o.oo8
in. gage copper alloy C26000 strip, a simple hand-held propane torch with
a wide cone tip was ade~uate to carry out brazing. However~ an air-
acetylene or similar hotter flame might be more versatile if a varlety
of metal alloys and gages are to be joined. Strip widths of about 1 in.
or less are preferred when utilizing hand-held propane torches since it
becomes more difficult to apply uniform heat across the width of the
strip segments as the width increases.
~ eferring now to Figure 5, there is depicted therein a vertically-
mounted pneumatic hammer 40 provided with a striker head 42 specifically
designed to uniformly reduce the joint 7 with minimal distortion of the
adjacent strip areas. The striker head 42 and anvil 44 present flat
faces to the strip so reduction becomes self-limiting as base metal gage
is approached. Pneumatlc hammer 40 is connected to a source of high
pressure air (not shown) via inlet _.
--10--
soos~
~z~
~ xcessiYe hammering and metal flow when reducing a
brazed and dressed ~oint to parent metal gage will often
result in metal cracking, doglegging, excessive wcrk hardening,
and "oil can" effects. Thus, excessiYe hammering and the use
of opposed convex hammer/anvil faces in reducing brazed ~oints
in narrow width thin gage strip is highly undesirable. It
has been found in accordance with another aspect of the
present invention that by establishing the diameter of striker
head 42 to be approximately twice the width of the metal strip
and by controlling the hammer pressure in accordance with the
properties of the strip material a self-shimming effect takes
place upon hammering of the joint.
~ pon brazing, the areas of the strip segments adjacent
the joint are subjected to a moderate annea~ and both these
areas and the joint are softer than the parent metal of the
remainder of the strips. When hammering is carried out for
short periods of time at pressures lower than would deform the
parent metal of the strip segments and striker head 42 extends
to the parent metal areas, excessive work hardening and metal
flow is avoided and a self-shimming effect takes place--with
the parent metal of the strip segments acting as ~ shim.
It should be apparent that striker head 42 need not be of
a round configuration, the only requirements being that the
face thereof be flat and of a longitudinal dimension or
extent approximately twice the strip width. The aforementioned
striker head geometry and size relatiQnship has been found to
eliminate ~ost of the inhomogeneity of deformation which often
resulted in "oil can" effects.
Another important aspect of the present invention lies
in the establishing of an appropriate gap bet~een the cut
~005-r;~B
~$~;~7
ends 11 of strip segments 4 and 5 prior to bra~ing of the
~oint. During heating of the braze material the metal cr
alloy strip segments being ~oined will expand. If the gap
between the strip segment ends is too great, brazing becomes
quite d~fficult and excessive amounts of braze material would
be required. If the gap is too small, excessive overlap of
the strips occurs~ requiring excessive reduction ope-ations
which cause doglegging and "oil can" effects in the metal or
alloy strip as discussed hereinabove. These problems are
particularly severe in joining of narrow widt~. thin gage strip
material since it is intended to carry out the brazing opera-
tion as quickly, inexpensively, and efficiently as possible.
When using a hand-operated torch on thin gage strip, excessive
heating would occur rapidly where a wide gap exists, and
difficulty in completing an effective joint would occur.
Excessive reduction problems would exist where too narrow a
gap and resultant overlap of strip segment ends exist.
Since it is not precise as to ~ust exactly what amount of
heat will be applied to just what total area and for how long,
it is necessary to approximate by calculation a gap size which
for a particular metal or alloy strip will be most likely to
result in successful ~oints. A sample calculation in accordanoe
with the present invention for copper alloy C26000 follows:
(1) The coefficient of thermal expansion ~ for alloy
C26000 is about 2 X lO 5/ C.
~ 2) Utilizing the equation
t QO (l + ~T), where
Qt is length at final temperature in cm;
QO is original length in cm;
T is final temperature, C.
-12-
9005-i~B
~23~7
(3) Assuming that the heated area of the strip segments
ad~acent the ~oint to be approximately 1.5 cm C9/16 in.) and
that the te~per~ture within this re~ion to exceed the melting
point of braze metal, typically 600-650C by approximately
100C. Therefore, the average final temperature can be taken
as about 700 C. Hence:
Qt = unknown
QO = 1.5 cm
T = 700C
Using the equation above,
Qt = 1.5 (1 + 2 X 10-5 (700C))
~t = 1.52, and
~t - QO = 0.02 cm or.2 mm = desired gap
Figure 6 depicts a joint wherein upon the setting of a
gap in accordance with the above calculation the cut ends of
strip segments 4 and 5 just "kiss'1 after brazing and reduction.
This is the ideal ~oint inasmuch as a minimum amount of brazi~
material 8 is required for ~oining and excessive metal removal
or deformation to reduce the ~oint to parent metal gage is
unnecessary. Figures 7(a) and 7(b) on the other hand depict
a resulting joint where no gap or an insufficient gap between
strip segments 4' and 5' was provided. As can be seen from
Figure 7(a), excessive amounts of braze material were required
to fill the interspace between the strip segments 4' and 5'
rendering the brazing process more difficult and expensive.
Moreover, as can be readily seen from Figure 7(b) excessive
metal and braze material flow has resulted from the reduction
operation carried out to reduce the ~oint to parent metal
gage. This excessive hammering typically results in
unacceptable product processing, poor strip edge geometry,
9005-i~B
S~7
dog legs, splits, etc.
Having thus described the various aspects of and means
which collld be utilized to carry out the process of the
present invention, such a process will be described for
joining a particular strip m~terial:
(1) Assuming the two strip segments to be jGined to be
3/4 in. X o.oo8 in. copper alloy C26000, a desired gap of
0.02 cm is established in accordance with the hereinabove
calculation.
t2) 5ach strip segment is placed in the cutting device
depicted in Figure 2. This involves placing each strip
against guide walls 13 and flat on the upper surface of base
elements 12 so that ends 10 project into the cutting zone of
guillotine cutter 15. The str~p segments 4 and 5 are cut by
lowering cutter 15 to produce matched cut ends 11.
(3) A 0.02 cm feeler gage (32) is selected and placed on
shaft 34 of brazing fixture 20 and rotated midway into the
gap between edges 30 of anvils 29.
(4) One strip segment is clamped in fixture 20 (Figure 3)
on one side of feeler gage 32 using surface 28 of anvil 29
and machined faces 24 of alignment steps 22. The end of this
strip should abut flush against feeler gage 32. Similarly,
the second strip segment is clamped into place on the other
side Or and butting against feeler gage 32. Clamping is
carried out by rotating screws 27 till they secure the strip
segments against surface 28 of an~vil 29.
(5) Feeler gage 32 is then rotated out of the joint area
bet~een the two butting strip segments.
(6) A strip of brazing paste is applied across the gap
bet~Jeen strip segment cut ends 11 being sure to get material
-14-
~005~
2387
into the gap using a minimum of paste. (One preferred way o~
applying brazing paste in such a Joint would be ~ith the use
of a syringe which results in a somewhat precise amount of
paste being laid into the gap between the butted strip ends
without the need for skilled labor or expensive devices.)
(7) Flame from a torch (preferably har.d-held) is applied
from the underside of the butting strip segments. The flame
is played along the ~oint or braze line only long enough to
assure complete melting of the braze material.
(8) The joined strip material is unclamped and flux from
the brazed joint is wiped off. The ~oint is inspected for
complete attachment. If incomplete oining has occurred, the
st~ip may be reclamped after which a small amount of brazing
paste can be applied to the open area and gently torched till
melted. If the ~oint is bad, the entire section can be cut
out and the process repeated.
(9) Both sides of the Joint are dressed with a flat file
paying attention to remove only excess braze. To facilitate
dressing, the joined coil section can be clamped to any
s~itable dressing fixture. This operation serves to minimize
the hammering needed to achieve parent metal thickness at the
~oint area.
~ 10) Hammer the ~oint area to gage by placing the strip
~oint on anvil 44 and activating hammer 40 with a foot pedal
or the like (not shown) while at the same time moving the
joint back and forth under striker head 42. Movement should
be in the longitudinal direction of the coil, and hammering
should preferably be carried out for a duration in the range
of about 5-10 seconds. In hammering narrow width thin gage
copper alloy strips, hammer air pressures in the range of about
900,-i~B
20-4Q psi have been found to ~e satisfactory. ~ny increase
cr slight widening of the strip at the ~oint loca~ion can
easily be eiiminated by edge filing of the joined strip.
Various means and methods can, of course, be utilized to
carry out the various steps of the afore~entioned process of
brazing s'rip segments end to end. For example, instead of
placing a braze paste in the jo nt between the strip se~ments
it would be possible to paint the strip segment ends with a
suitable flux and then heat to brazing temperature. Upon
attaining brazing temperature, a thin wire of brazing alloy
can be touched to the joi~t in order to accomplish joining of
the two strip segments. This particular method of applying
braze material provides for very good control of the actual
amount of braze material applied to the ~oint and helps to
avoid the need for excessive hammerirg or metal reduction of
the brazed joint.
In accordance with the concepts of the present invention~
pairs of brass strip 0. oo8 in. gage by 1/2 in. l~ide were placed
end to end in a clamping fixture with a separation between
the strips governed as disclosed herein by the linear
coefficient of expansion of brass. Both ends of the strip
segments were painted with a fluxing agent and heated with an
oxy-acetylene torch. Upon attaining a suitable temperature,
a thin wire of brazing alloy was touched to the joint in order
to accomplish ~oining of the strip scgments. Tensile prop-
erties of a group of such brazed ~oin's using several brazing
alloy types are shown in Table I and compared with the
tensile strength of the parent metal strip in bcth the as-
rolled and the annealed conditionsO
~3~5Z;~B7
TABLE I
TENSILE PROPERTIES OF ~UTT BRAZED
0.008" GAGE ALLOY 260 BRASS STRIP
0.2% Ultimate
Yield Tensile Elongation
Strength Strength in 2"
_ Sample (ksi) (ksi)(Pct.) Notes
A 24 48 6 Cu-Sn-P braze
metal
B 21 44 6 Cu-Sn-P braze
metal
C 23 49 7 Cu-~n-P braze
metal
D . 20 30 9 Ag-Cd-Cu-~n
braze metal
E 22 33 7 Ag-Cd-Cu-Zn
braze metal
F 24 37 4 Ag-Cu-P braze .
metal
Alloy 260 103 109 2 Parent metal for
extra spring above samples
Alloy 260 22 45 . 40 Typical values
annealed-
Several additional brazed ~oints were made in accordance
with the process utilized in production of the samples in
Table I with the difference that the brazed joints ~ere
purposefully made using excess braze metal and then hammered
in order to reduce the joint thickness to that of the parent
metal strip. Tensile properties of these additional samples
are shown in Table II.
-17-
9005-i;lB
TABL~ II
TENSILE PROPERTIES ~F BUTT BRAZED AND HAi~MERED
TO RAGE 0.008" ALLOY 260 BRASS STRIP
0.2% Ultimate
Vield Tensile Elongation
Strength Strength in 2"
S.~mpIe (ksi) (ksi) ~ ) Notes
G 27 52 9 Cu~Sn-P braze metal
H 32 54 8 Cu-Sn-P braze metal
I 29 53 6 5u-Sn-P braze metal
J 47 55 8 Ag-Cd-Cu-Zn br~ze
metal
K -- 40 2.5 Ag-Cu-P braze metal
It is apparent that there has ~een provided with this
invention a novel process for economical, efficient~ and fast
~oining of narrow width thin gage strip segments which fully
satisfy the objects, means, and advantages set forth herein
before. While the invention has been described in combination
with specific embodi~.ents thereof, it is evident that many
alt.ernatives, modifications, and variations will be apparent
to thcse skilled in the art in ligh~ of the foregoing
description. Accordingly, it`is intended to embrace all such
alternatives, modifications, and variations as fall wi~hin
the spirit and broad scope of the appended claims.
-18-
