Note: Descriptions are shown in the official language in which they were submitted.
2~78~
Title: C~ PRO~C~ION ANODE AN~) ~ETHOD
~LQ~
Tbis i~lVentjOn relates generally to an allode, and more pc~rticuLarly to a
smooth ec3ged valve metal ~esh strip ele~ent whic~ may be fabricated into
S cathodic protection anodes for protecting, for exa~ple, storage tank bottoms or
steel In steeI reinforced concrete.
The preserlt inven~ion comprises certain impro~ements in fabricated
anodes such as shown in copending applic~tion of Michael K. Baach and l;~av~d
Kroon, Serial No. û7/6~9,~34 filed ~arch 15, 1991, entitled "Cathodic ProtectionSystem and ~ethod for Above Grolmd Storage ~ank Bottoms" The invention
also compnses certain improve~ents in tbe coiled o~ rolled valve metal mesh
disclosed in prior ~J.S. Patent No. 4,900,410.
In such prior U.S. patent, rolls or coils of valve metal mesh ~re employed
1~ to fabricate the allode. The coiled or rolled n~esh has several drawbacks, some
of w~ich are described in tbe patent. Por example, prior to fabric~tion or fixing
the LIlLrolled mesh is preferably stretched longitudinally and/or laterally to
improve its flatness and avaid bulges. Such stretching cbanges the dirnensions of
the mesb ~nd f.atness is not really acl~ievable. Because of tl~e lack of flatness the
ion conductive overlay of polymer modified concrete, whicll m~y be quite thin,
may h~e to be applied in se~eral layers. ~e tnesh may be only substantially
e~bedded by the first ~ayer. Any protruding sections are ~lattenecl an~/or
trimnled before applying the next layer or layers. Tbis makes the overla~ step atirne consuming and expensive project.
~5 ~Iak~'ng tbè above indicated problem ~40rse is the fact that coils or rolls of
mesh are usually slit f~om larger rollsl in much the same fashion as a steel coil is
slit. ~ider coils are uncoiled, slit ~nd then recoiled. ~c slitting process, even
OII steel sheet formf, burrs, but on Inesh, the edges beconle erose, sharp and
jagged~ and tend to catch on j~lst ab~ut anything such as workers' clothing, shoes,
boots, etc.
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Paving machines for dccks or slabs or spreaders used to form the oYerlay
of polynler ~nodifiecl concrete v~te~ use powered rollers alld a~ ers to distIibute
smooth ~nd texture the wet concrete. An exan~ple of such machine is the well
known Bl~-WELL~ paver sold ~ LL, a divisio~ of ¢MI Co~poration of
Canton, South ~)~lcota. I~ the roller o~ auger catches on something it can wrap
around the roller or alIger very quic~dy creating a real birds nest, all in a matru
of wet concrete. If ~he part ca~l~ht is ~ reticulate anodc grid for a cathodic
prote~tion systern, the erltire carefully prepared and fabricated anode may be
pulled apart and disinte~rate ~n very short order. ~ rernedial ~easures arc not
talcen quickly the entire cast se~ment of deck or paving ~ay need to be replaced.
~t hns been remarked tbat watcbin,~ a concrete placement crew take such action
has real e~tertainmellt va~ue because of the sl~eér fren~y inv~lved.
Coiled rnesh str~p5 havmg a curvature ~et are di~icllIt to weld to each other
because of the lack of flatness. They won't readily lay flAt over one another.
They usually re4u~re a clamp or at least the top ~nesh strip to be pressed down
before a tack or spot veld c~ be made. Evell then a mesh-to-m~sh spot or tac1c
weld connection is not as strong as two spot welded non mesh strips
~nother major problem with coiled mesl~ strips used ~s anodes is that the
lack of flatness carl creat~ a short b~tween the anode and the metal to b~
protected, thus rendering ~he entire cathodic protection system inoperative. Such
shorts discovered after an overlay has been poureà or after a storage tal~ has
bcen built abo~e tbe anode can create very e~p~nsive corrective requ~rements.
As indicated in the lloted prior copendin~ application, it is important tbat theallode not touch the bottom of the tanlc which is constructed closely thereover.Tn steel rei~orced concrete bridge deck rep~irs, for exarnple. ~e spalled
or broken concrete ;s removed and chipped away before tbe anodc is pl~ced OI1
the deck to thén be embedded in an ion conductive overlay of polyn~er modified
concrete which becornes the new sufface of tl~e bridge deck. In the pleparation
of the bridge ~eck some of the steel reint`orcing may be exposed so that the allode
~0 mesh must be elevated above the exposed steel. ~or coiled, culve set, mesh
strips, this is difficult and any required spacing is problematical. This is
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p lr~i~ularly true since during the fal:~ic~tion ~Id subsequent pouring or pavillg
yrocess workers will out of necessity be ~alkin~ ver the anode.
It is therefore i~nportant and desirable to provide an ~ode n~esl, strip
from which a w~de variet~ of anodes rnay readily be ~bricated whicll does not
haYe either thç &urve set or ja~ged edge proble~s of coile~ mesll s-trip. It is also
important that the valve ~letal mesh strips be of low cost, easily packagecl ~ndshipped~ and easily handled arld fa~ricated or joirLed at the construction site to
fonn a reliable cathodic pro-tection anode.
~ .
In its preferred forrn, the elon~a.ed llat anode strips o~ the presellt
invention are formed of annealed titanium strips. The strips bave at least one
narrow longitudinal section that is not expanded with the balance of the strip
being expanded mesh. The unexpanded section may be at oIle or both edges, or
in the m~ddle. The lateral edges of the strip are ei~er tl~e unexpa~lded
L longitudinal solid section or a mesh section that is not cut or sheared. In the
latte~ configuration the edge presen~s a shallow yet srnooth scallop. Although
titanium is preferred, other suitable valve base metals may be used such as
aluminu~n, taIltalum, ~ircorlium, niobium, or alloys thereoP The strips after the
mesh e~pansion are coated with an ele~trochemically active coating which
~0 prevents passivatio~ of the valve metal s~lrface. The coati~g may for example be
a noble metal sucb as platinum or mixed metal oxides.
The unexpanded longitudinal section of the strip may be about 1 crn in
width or more so that two overlying and juxtaposed strips m~y readily be tack
welded to each other. ~e total strip expanded Inay be ~-12 cm in width, as an
ex~uple and the strip is cut into nom~nal un~fortn length~ sudl as 2 meters for
stacking, packaging and shippin~ to the anode construction site.
Th~ strip has sufficient~au~e or t~ickness to be able to be stacke~ e
boards and sbipped for f~bri~ation and assembly. The une~panded se~rncnts of
the strip contribute to ehe handleability and stiffness of ehe s~ips. ~he thickness
of tbe strip may ~e from abou~ 0 25 to 2.0 mr~.
~7~fi~ ~
The strip is expanded by ~ormin~ lon~itlldi~ ly exten~ g brickwork s]its
of equal le~gtll in ~e ~rea to ~e expanded and thell plllling the st~ip ~ridtllwise
to ~orrn a u~form dialnond pattern mesh. Cut or f~achlrçd later~ eclges are
avoided.
S The strip in fabrication has sufficient ~latness ~d stiffi:lcss to be readily
joined to other strip, and yet caIl readily be bent to go around corners or cut with
tin snips. ~Iore innportantly t~e strip can be courlted on to stay where it is
supposed to stay in the noImally chaotic and abusive environment of heavy
construction.
To the accomplishrnent of the fore,~oing and related ends the invention,
then, comprises the features hereinafter fully described and particu~arly pointed
out in the claims, the follow~ng description alld the anne~ed drawings setting forth
in detail certain illustrative embodiments of the inventioIl, these being indicative,
however, of but a few of the various ways in which the principles of the invention
may be employed.
Ill said annexed drawings:
Fi~lre 1 is a, schematic illustration of a steel reinforced concrete slab or
bridge dec3c wi~h a fal~ric~ted anode in accordance with the present irlvention
prior to the application of an overlay;
Pi~ure ~ is a fia,gmentary plan view of a preferred forrn of ~node strip in
accordance 4itl~ the present invention;
~i~ure 3 is a sirnikar plan view of another i~orm of anode strip;
Fi~ure 4 is ~ similar view of yet another form of anode strip;
ZS ~i~ure S is a view showin~ the strip of ~i~ure 4 t~ck welded to a traI~sversc
conductor ribbon or bar;
Pigure ~ is a view showing the strip of ~igure 3 tacl; welded to such ribbon
nr bar;
~igure 7 is a view sim~lar to Figure S but showing the strip/bar conIlection
supported on an el~vatin~ shim w~th the aid of a "christInas tree" fastener;
Figure 8 is A similar view but w~th the strip of ~i~ure ~;
2 ~
Figure ~ is a vertieal section through the steel re~nforce(l coI1crete
illustrating how the shims and ~asteners suppo~ the anode strip grid above any
exposed steel rei~forcing in the concrete;
Fi~ure lO is a view similar lO Figu*e 7 but showing the fastener and 5hirn
S offset from the ribbon or bar;
Figure 11 is a 6imil~ i11ustration of an of~set cormection and support ~ith
a mesh strip o:P the type seen in Fi~u~e 3;
Pigure 12 is a somewhat enlar~ed horizorltal section t~ken from t~e ~ine
1~-12 of Figure ~ sllowing the fastener in section and the s~im in top plan;
1~ Figure 13 is a top plan vievv of a crossing intersection o~ strips as seen in
Figure 4;
Figure 14 is an inte~sectiQr~ of the strips of Fi~ure 3;
~igure 15 is a~ intersection of the strips of Pig~re 2;
~igure 16 is a top pIan view of an anode for a ta~lc bottom, for example
~vhich may be constructed with strips of the present invention:
~igure 17 is a top plan v~ew of a corner which ~ay be &onstructed by flat
folding the strip of Pigure 4, the co~ner bein~ supported on a fastener an~l shim;
~igure 18 illustr~tes how arl obtuse an~gle bend is ~ormed;
Figure ~9 ill~strates how an acute angle bend is formed:
~0 Fig~re 20 is a ri~ht an~le corner formed by the strip of Figllre 3; and
Figure 21 is a sirnilar corner formed by the strip of ~igure 2.
Nrrs
R~fe~rirl~g initially to ~igure 1 there is illustrated a steel reinforced
co:~crete slab or deck 30 which is reirlforced by reinforcin~ steel sho~n ~enerally
~5 at 31 and which bas positioned on the top surface thereof a grid ~pe overlay
allode shown gen~rally at 3~, fabrieated in accordance with the present invention
The grid anode is illustrated before it is bul~ed by tbe ioll conductive overl~y. In
the illustration of Figure 1 the grid is formed by positioning ~onductive ribbons
Ol bars seen. at ~4 and 35, then placing the mesh strips 36 tra~lsversely thereof
E~ch strip is tack or spot welded to the conductor ba~ to forrn a reticulate grid
or pattern, such welding not only securing the components of the grid to~e~er but
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also providin~ a low resistance electric~l connection between each of the
CO:t}lpOllelltS, Befole the overl~y is po~red, the ~rid may be electrically connected
to rectifier 3g which is connectecl at 39 to the bar 34 a~d at 40 to the reinforc~n~
steel. The connection may also take place after the pouring of the overlay. In
S thi~ m~ner a cathodic proteetion current is impressed between the anode grid
and the reinforc~ng steel to abate corrosion and the well lalown deleterious effects
such ~ corrosion has on steel rei~orced con~et~ b~idges and deck~.
Either ribbons or bars may be utilized as the tran~verse con~uctors
i~lustrated in Figure 1 T~e term "~ibbon" simply denotes a bar of ~ ler
dimension. J3oth the ribbon and bar have a titamum substrate which m~y h~ve
a coating of one of the noble metals or of mixed metal oxides. For both the
ribbon and bar, the colnposition of the substrate iç preferably ASTM ~65;
titanium gr~de one or two. The ribbon is preferably 0.25 ~nch in width, 0.0~5 inch
in thicl~ess, having a ~,veight of 6 pounds per 500 feet ancl a resistance of 0.042
ohms per foot. ~ anode ribbon with a titanium substrate and a TIR ~000 m~xed
n~etal oxide coating, i5 available from a materials protection company of Houston,
Texas. The ribbons come i~ 500 ft reels.
The conductor bar may be of the same substrate. The conductor bars or
rib~ons are use~ to form the grid pattem and thereby reduce the voltage drop
~0 along the mesh strips. The conductor bars may be preferably 0.5 inch ill width,
0 0~0 inch in thiclcness, have a weight of 10 pou~ds per 250 feet, and have a
resistance of 0.013 ohms p~r foot. S~lch conductor bars are avail~le in 250 ft
~oils.
Referring now additionally to ~i~ures ~-4 it will be secn that the mesh
~5 strips 36 may take several fornls. In each form the strip i5 pr~m~r~ly open mesh
and includes at least one solid longitudinal section which is of a width to facilitate
the t~ck welding of strips either to the~nselves or to the conductor bar or ribbon.
In Fi~ure ~ there is illustrated a mesh strip 40 which includes a ~enter
longitudinally extending solid section 41 with raesh sections 42 an~ 43 on both
sides.
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The forl~l of strip in ~i~ure 3 in~icated at 45 has one solid longitlldir~al
section 46 which forms one lateral ed~e. ~n expancled or mesh sect;on 47 forms
the adJacent lateral ed~e.
In Figure 4 there is illustr~ted the ~esh s~rip 3b which is seen in Figure
1. The mcsh strip 36 includes solid lateral borders 4g ~nd 50 with a mesh sectioS1 therebetween.
All t~ree fo~ns of mesh strip may ~se fonned by forr~g r~latively short
lorlgitudinal brickwork slits in titar~um metal 5trip. Suçh siits will IlOt be formed
in the solid sections 41, 4~, 49 or 50. ~fter ~e slits are formed the stnp is
expanded laterally literally by p~ g at the edges to form the open me~h
neh~orl;. rn conr~ection with the embodimellts of Figures ~ and 3, care is takenIlOt to fra~ture or cut the lateral edges of the mesh strip seen ~t S~ and 53 in the
Fig~re ~ embodiment, and 54 in the ~igure 3 ernbo~iment. Thus even though
scalloped in the diamond pattern formed, the lateral edges ~e uncut or
unsheared ~nd do not form a jagged ed~c which can catch on work:ers' clothing
sueh as gloves, boots, or the like. The embodiments of Figures ~ and 3 form
smootb no~jaggecl lateral ed~es even ~ough on the mesh side those cdges are
not linear. In the embo~iment of ~i~ure ~ the lateTal ed~es are smooth and
linear.
?0 Althou~gh titan~um i9 iIldicated to be the preferred valve metal, ;t w~ll be
appreciated that other valve metals may be employed such as aluminum,
tantalu~, ~ircor~um or niobium, and alloys thereo
After the strip is expanded to the form~ sllown in Pigllres 2-4, it is then
coated with an electrochemica~ly active coating wb~ch prevents passivatiotl of the
?~ valve Ihetal surface. The coatin~ may be a mLxed metal oxide coa~ g such as tbat
note~ above for ~he titanium ribbon or bar. ~e coating also may be of ~ noble
lllet~l. A wide varie~ of electrochemically active coatings Inay be employec~ and
reference may be had to prior ~J.S. Patent~ 4,51~,886, or 4,331,528, or U.K.
Pub]ication 896912, published ~ay ~3, ~962, all of which ~how titanium anodes
with a va~e~ of mLl~ed me~al oxide coat~ngs OI Iloble metal coatiIIgs.
The mesh strips after being coated are flat ~ld c-lt to len~th for p~ck~ging
alld shippi~g, ~ nominal shipping len~th r:lay be on the order of 2 to 4 nleters.
While the dimensions of the mesh st~ips may vary widely, it is important
that the strips be flat, have smooth or nonja~ged lateral ed~es, and ~e rel~tively
stiff. ~o achieve the latter the thickness of the s~r~p rna~f, for exanlple, be from
about 0.25 to 2.0 rnm. The mes~l strip may also vary considerably in ~idth ~d
a preferred overall w~dth may be on the order of 6 to 1~ cm,
As will be explained, tlle purpose of th~ unexpanded or solid longitudinal
sections of the strip is to facilitate tack or 5pot welding of the strips, both to each
other a~d to the underlying conductor bar or ribbon. To fa~ilitate this spot
weldi~g, the unexpanded or solid sections should be on the order of at least 0.5Clll and preferably on the order of approxlmately 1 cm. Wider sections may be
employed.
Referring now to Figure 5 there is illustrated a mesh strip 3~ overlying a
1~ conductor bar or ribbon 34 with the mesh strip secured to the conductor bar or
ribbon by two tack ~r spot welds shown at 56 and 57. Aïtbough tack welds are
sllowII at both lateral ed~es of the mesh strip 36, it wi~l be appreciated that for
fabrication and electrical purposes, only a single tack weld need be employed,
In Fi~ure 6 there is illustrated the mesh strip 45 tack welded at 59 to the
~0 conductor bar or rib~on 34. A~ain the snlid unexpanded edge 46 facilitates the
tack weldin~ of the mesh strip to the conductor bar or ribbon.
Re,ferr~g now to l:;igure 7 there is illustrated an intersection of a Inesh
strip 36 and a conductor bar or ribbon 34, with the intersection and connection
bein~ supported in an elevated or spaced condition froln the rein~rced concrete
structure. 'rhe connected intersection is supported on a shim showll at 62. The
sh~m is bene~th the intersection and the shim, mesh strip an~l conductor bar or
ribboll are all anchored to the concrete structure at the location shown by a
fastener ~3 which extends throu~h all three. Similarly, in Figure 8 the n~esh strip
40 and the conductor bar or rib~on ~4 ~re interconnected and supported in
elevated position by the shim fi5 and fastener 66.
~9~ ~ ~.3 P~
The rcason for s~lpporting tlle grid of the anode in a spaced or ele~at~d
~osition with r~gard to ~e steel reinfo~ced çoncrete struçt~re is s~en more clearly
itl Figure 9. In a typical repair or replacement of a ~teel reinforced concrete
decl~, the sp~lled or loose con~rete f~olII the corrosioll of the steel rei~orcing bars
S is ~emoved providing a relatively ~at yet solid top surface indicated a~ 68. The
spalled coxl~rete is usually r~moved with a j~ckham~er or other equ~lly less
exacting instru~ent. In the removal process, some of the steel reinforcin~ bar
may be left exposed as indicated at 6~ and 70. If the expose~ reinforcing steel
contacts the anode grid, a short will occur ma~cing the system inoperative.
As seen additionally in ~i~ure 12 the spacing shims ~5 may be circular clie
cut forms of ~ fairly thick plastic rnesh and the fastener 66 simply ext~Ilds throu~h
an ope~ing in the mesh. The fasteners ma~ be of the "christmas tree" type
pro~ded wit~ fingers indicated at 72 which whell inserted in drilled holes 73 lock
the fastener in pl~ce. The shi~ is sirnply placed over the hole, and the fastener
is inserted through a hole whiçh may be drilled or punched in the so]id portion
of the mesh strip, ~nd the conductor barl the intersection of whiçh is supportedon top of the shim. A washer S~OWIl at 74 nlay be provided under the head of
the fasteneI, if desired. Both the fasterler ~d shim are plastic or non-çonductive
and may readily be encased in the ion conductive overlay which is formed over
~0 the top of the fabricated grid. The solid portion of the mesh strip may be tacl~
welded to the ribbon or b3r on either side of tbe drilled hole accomlnodatin~ the
stem of the ~stener.
Tn ~i~res 10 and 11 there is illustrated an intersection which is supported
~n elevated or space~ colldition by fasteners and shi~s vhich are ~fset from the
tack weld interconne~tion of the mesh and collductor bar. ~n Figure 20 the
fastener extends through a hole punched in the mesh section 51 (~f the strip with
~he shim nonetheless extencling beneath tlle conductor bar or ribbon 34. II
Fi~ure 11 the mesh strip 45 is tack welded to the b~r or ribbo~ 34 as iudic~ted
at 5~ and the shim ~5 extends bene~th the ribbon at the ~ntersectiorl w~th the
fastener ~ extendin~ through the expanded mesh section. The dia~nond shape
openings in the mesh ~e~tion are of sufficient size tbat the steIn of the f~stener
~10-
2 ~ 3
fits through the opening witho~t requiritlg a drilled or punched hole. 'ln any evel1t
as seen in Fi~lres 7-1~ tlle el~va~ed or ~paced auchoring of the intelsectioIls uf
the mesh strip ~d/or mesh strip and bar enable the grid o~ the allode to be
spaced fror~ ally expos~d steel in the structure and the fasteners are of sufficient
streIl~th that if someone steps on the mesh ~rid as in Figure 9, there is enou~htensioII in the ilat ~nd stiff mesh strip to cau~e it to spri~g back to its spaced or
elevated position.
It will be appreciated that the Inesh strips may be joitled to each oLher as
easily as they are joine~ to the ribbons o~ conductor bars. They may also be
supported in the elevated or spac~d condition seen ~n Figure ~ at such
intersections by the employment of the shims a~d fasteners. Figure 13 illustrates
a right angle intersection between two rnesh strips 36 of the ype seen in Figure4. The intersection of the solid bo~ders may each be tack welded as ~een at 80,
81, 82 and 83. It will be appreciated that normally four such welds will not be
reg,uired. The fabricator however has a number of options in making the
connectiou and intersectio~.
In Fi~ure 14 the~e is i~lustrated a31 intersection of t,wo mesh strips 45 of thetype seen in Figure 3. A sirl~le tac~ weld 8S is employed join~ng the two solid
sections of the mesh strips. ~n Figure 15 there is illustrated a ri&ht ~ngle
intersection of two mesh strips 40 of the type seen in Figure 10 and again a single
ta~k weld is employed at 87 join~ng the respective solid longitlldinal sections of
the overlying mesh strips. It will be appreciated that the intersection need not be
a right angle intersection and that the layout or fabrication of the ~rid may call
for other angular connection~. ~t will also be appreciated that the strip may betack welded end-to-end to form the cut to length sections into much longer
sections, a~ain using the solid longitudinal sections overlying each oth~r to
facilitate the tack weld~n~.
Fi~ure 16 illustrates ~ fabric~ted allode ~rid of the type which m~y be used
to protect new or reconstructed circular tank bottoIns such ~s described ~n -the~0 aforenoted copending application Se~ial No. 66g,934. The anode grid of Fi~lre
16 may be constructed on a layer of comp~ted sand and is designed to protect
2 ~
a tank bottom which would be constructed rnostly above the anode grid. ~'he
circlllar tank 90 util~zes an anode grid shown generally at gl which is formed of
chordal conductor bar 9~, diametral conclucto~ bar ~3, and symmetrically disposed
chor~al conductor b~r 94. Extendi~g no~nal to s~ch conductor bars Oll
S approximately 4-foot centers are anode ~esh strips ~6 in ~ccord~ce with the
present invention. ~n ~ddition to the Inajor conductor bars 9~, ~3 a~d ~4,
relatively short curre~t distribut~r bars may ~e prov~ded ~or the shortest mesh
strips as illdicated at 98, 99, 100 and lO1. Power lead co~ections from the
r~ctifier are provided at 103, 104, 105 and 10~ while the trian~ular symbols
indicate the locations of reference electrodes as seen at 108 and 10~. ReferenceIhay be had to the noted copendin~ applicatiorl for a wide variety OI grids ~vhich
may be constructed for the protection of tank bottoms ~tili~ing the mesh strip of
tlle present invention. ~rid type ano~es co~stnlcted urlder tank bottoms ar~
subject to the same type of chaotic and abusive environment as ~rid ~pe anodes
which are to be encased on a concrete stn~ct-ure or deck with aIl overlay.
~Ioreover, both requi~e care and precisior~ in construction in or~er to functionproperly.
~eferring now to Figures 17~0 it will be seen that the mesh strips of the
present invention may be flat folded at certa~n angles to create bends, either at
a right an~le, or at the acute or obtuse angles illustrated. In Fi~e 17 a mesll
strip of the type seen in Figure 4 is bent to a flat fold at a 45 an~le to form the
right a4gle ~end sl~ow~ he interio~ crotch of the bend may be s~pported on a
spaci~g shim indicated at 65 and anchored in place with fastener ~. ~ Figure
18 an obtu~e angle bend is for~ed. To keep the mesh ~trip in tlle flat stiff
~5 condition at the bend the two solid edges m~y be tack welded together as
il~dicated at 112,
In Fi~ure 1~ ~ acute angle bend is formed and ag~in the opposite solid
edges may be tack welded to~ether as seen at 114. In Fi~e 20 a ~esh ~trip of
the type ~een in Figure 3 is flat folded to forrn a right ~ngle bend. Figure ~1
illustrates a nght an~le bend ~th a mesh s~ip of the l;ype see~ in ~igure ~. ~3oth
are simply folded a~ a 45Q angle to create the right angle bend. A flat fold w~th
~ ~ 7 ~
the mesl1 strip of th~ pres~nt inventioll ~ay readily be acbieved, If necessaly a
pair of pliers may be employ~d to form the crease. Also in the embodiments of
~'igures 20 and 21 a tack weld may be formed at 114 or 116 to ma~n~aill the meshstrip in its ~at ~olded conditioll.
S It can now be seen that the mesh strip af t~e present ~nvention has
sufficient flatlless and stiffness readily to ~e jo~lled to olher str~p, and yet c~
readily be bent to go around corners or to be cut v.~t:~ tin sn~ps and rejoined at
any ~ngle. More importantly the strip can be counted on ~o stay where it is
supposed to stay in the no~nally chaotic a~d abnsive environment of heavy
coIls~ction.
~Ithou,~h the iIIvention has been shown and ~escribed wi~ respect to
certain preferred embod~ments, it is obvious tbat equivalent altera~ions alld
modifications ~Ivill occur to others sl~lled in tlle art upon the reading and
understandin~ of t~i~ specification. ~e p~esent invention iilc~udes all such
e~quivalent alterations and modifications, and is lir~ited only by the scope of the
claims,
