Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 15~9
This invention relatcs to railway vehicle structure and in particu-
lar to a ~ear member for use between a pair of relatively moveable componenLs
of such structure.
It is ~oown ;n ~ e art ~o pl-ov;cle a weai- member ro~ )ri ~d of a
tal s~ >ol-t ~ ?~ by .~t l~:~t (~lle ~f ~ ir o~ l-(l.~;i\~ly l~,o~ hle
I O I I 1l ~ ?"'.'`' f r, O i. U I j 11 g 1 1-~ e ~ C !1-1) 011~-` n ~ S
fIom wear.
For e~ample, a wear member has previously been provided compr;sing
a metal support having a con~ uous planar supporting surrace, a po]y.neric
material, and means attaching the polymeric material to the support and
supporting same against tlle continuous supporting surface for the purpose
of providing a substantia]ly structurally self supporting wear member. That
wear melllber util;zes a reinforcing material in the form of a metal struc-
ture having openings therein. Such metal structure is welded directly
against the metal support whereupon a polymeric material is formed around
the metal structure on one side of the metal support resulting in the poly-
meric material being reinforced only along its inside portion while defin-
ing an exposed outside portion which is basically unreinforced.
It has also been proposed, in Vnited States Patent No. 4,188,888
issued Feb. 19, 1980, to provide a so-called wear member or liner for the
center plate structure of a railway vehicle which has a reinforcing
material, also in the form of an e~panded metal structure, embedded sub-
stantially centrally between opposed wa]]s or surfaces of a polymeric ma-
terial wll;ch serves as a m~trix for the metal structure.
Howe\er, the first-mentioncd wear member is deficient because
its outside unreinforced portion of polyn.eric nnaterial is the one subjected
to wear and Imder normal pressure during use has tlle tendel~cy to "cold f]ow".
The second-mentioned wear m.mber for center plate structure has-apertured
1 156189
reinforcing metal structure centrally embedded in polymeric material there-
of whereby the polymeric material has minimum tendency to cold flow; how-
ever, it is also deficient because it has minimum self supporting struc-
tural strength and basically must be used between confining bearing sur-
faces which it serves to lubricate.
An object of one aspect of this invention is to provide an im-
proved wear member for use between a pair of relatively moveable components
of a railway vehicle.
An object of another aspect of this invention is to provide an im-
proved method for making such improved wear member.
By one aspect of this invention an improvement is provided in awear member for a railway vehicle wherein the vehicle comprises a pair of
relatively vable components and the wear member is adapted to be supported
by one of the components and protects the components from wear during
relative movement thereof, the wear member comprising a metal support
adapted to be supported on the one component, a liner attached to the metal
support, the liner having opposed surfaces comprising an inner surface
thereof disposed adjacent the metal support and a smooth antifriction outer
wear surface engageable by the other component, the liner comprising an
ultra high molecular weight polymeric material defining the opening sur-
faces, and a metal structure embedded substantially centrally between the
opposed surfaces of the polymeric material which serves as a matrix for and
substantially completely surrounds the metal structure, the metal structure
having openings therein which receive the polymeric material completely
therethrough and provide better embedment of the metal structure, the
structure providing reinforcement and preventing cold flow of the polymeric
material, the improvement comprising: a plurality of metal members extend-
ing between the metal structure and the metal support through polymeric
-- 3 --
1~5B189
material disposed between the metal structure and metal support and its
associated one of the opposed surfaces, and weld means welding the metal
mem-ers in position between the metal structure and the metal support.
By a variant thereof, the metal members are defined as a part of
one of the metal support and the metal structure.
By another variant, the metal members are defined as an integral
part of the metal structure, the metal members having terminal outer ends
extending transversely of the metal structure through the polymeric mater-
ilal for contact with the metal support, and the weld means comprises a
plurality of welds welding the terminal outer ends to the metal support.
By yet another variant, the metal structure is a single-piece
expanded metal structure having a main body defined in a grid-like pat-
tern consisting of interconnected integral portions and the metal members
consist of selected detached end portions extending transversely from the
main body through the polymeric means in contact with the metal support,
the weld means comprising a plurality of welds welding the end portions
to the metal support.
By still another variant, the metal support, metal structure, and
metal members are made of the same type of metal.
By a variation thereof the weld means consist of electric resis-
tance type welds.
By another variant, the metal members are separate members dis-
posed between and contacting the metal structure and the metal support,
and the weld means comprises a plurality of welds welding opposite ends of
the metal members to the metal structure and the metal support.
By a variation thereof, each of the metal members has a main body
provided with a knife-like edge on at least one end thereof, the knife-
like edge piercing the polymeric material and contacting the metal support.
1 156~i89
By yet another variant, the ultra high molecular weight polymeric
material has a molecular weight of at least 2 million.
By a variation thereof, the ultra high molecular weight polymeric
material is polyethylene.
By another aspect of this invention, an improvement is provided in
a method of making a wear member for a railway vehicle including the steps
of providing a metal support adapted to be carried by one component of the
railway vehicle, attaching polymeric material to the support which defines
an antifriction wear surface which is slideably engageable by another com-
ponent of the railway vehicle, the attaching step comprising the steps of
fixing a metal structure having openings therein to the metal support and
forming the polymeric material in surrounding relation around the metal
structure to define a matrix for and to embed the metal structure therein
with the polymeric material extending through the openings, the antifric-
tion wear surface being defined by an outermost surface of the polymeric
material disposed opposite from the metal support,the improvement in the
method wherein the forming step is achieved before the fixing step and in
which the fixing step comprises: extending a plurality of metal members in
mechanical and electrical contact between the metal structure and the metal
support and through the thickness of polymeric material disposed therebe-
tween; operatively connecting an electrical welding system oetween the
metal structure and metal support while holding the metal members in the
mechanical and electrical contact; and electrically welding the metal mem-
bers in position between the metal structure and the metal support with the
electrical welding syste~.
By still another aspect of this invention, an improvement is pro-
vided in a method of making a wear member for a railway vehicle wherein the
vehicle comprises a pair of relatively moveable components and the wear
1~56i89
member is adapted to be supported by one of the components and protects the
components from wear during relative movement thereof, the method including
the steps of providing a metal support adapted to be supported on the one
component, forming a reinforced antifriction liner having one surface there-
of which is adapted to be disposed adjacent the metal support and having a
smooth antifriction wear surface engageable by the other component the form-
ing step comprising defining a plurality of openings in a metal structure
and embedding the metal structure in an ultra high molecular weight poly-
meric material which serves as a matrix for and substantially completely
surrounds the metal structure while simultaneously defining opposed surfaces
of the polymeric material, the openings receiving the polymeric material
completely therethrough during the embedding step resulting in better em-
bedment of the metal structure, the structure providing reinforcement and
preventing cold flow of the polymeric material, the improvement in the
method comprising the steps of: extending a plurality of metal members in
mechanical and electrical contact between the metal structure and the metal
support through the thickness of polymeric material disposed between the
metal structure and metal support and its associated one of the opposed sur-
faces of the polymeric material; operatively connecting an electrical weld-
ing system between the metal structure and the metal support, holding the
metal members in the mechanical and electrical contact; and electrically
welding the metal members in position between the metal structure and the
metal support with the electrical welding system, thereby resulting in the
liner of the wear member maintaining the smooth antifriction surface thereof
yet being fixed to the metal support in a high strength manner.
By a variant thereof, the plurality of metal members are defined
as an integral part of the metal structure, the metal members having termin-
al outer ends extending transversely of the metal structure through the
, - 6 -
1 ~56~89
polymeric material for contact with the metal support, and the weld means
comprises a plurality of welds welding the terminal outer ends to the metal
support, and wherein the extending step comprises: extending the portions
through the thickness of polymeric material during the embedding step.
By another variant, the metal structure is a single-piece expanded
metal structure having a main body defined in a grid-like pattern consisting
of interconnected integral portions having opposite terminal ends the metal
members consist of selected detached end portions extending transversely
from the main body through the polymeric means in contact with the metal
support, the weld means comprising a plurality of welds welding the end
portions to the metal support, and therein the extending step comprises:
cutting one of the terminal ends of selected ones of the integral portions
away from the main body; bending each selected portion about its opposite
terminal end so that it extends transversely from the main body; and ex-
tending the selected ones of the integral portions through the thickness of
polymeric material during the embedding step.
By still another variant, the plurality of metal members are
separate members disposed between and contacting the metal structure and the
metal support, and wherein the extending step comprises: extending the mem-
bers through the thickness of polymeric material after the embedding step.
By a variation thereof, each of the metal members has a main bodyprovided with a knife-like edge on at least one end thereof, the knife-like
edge piercing the polymeric material and contacting the metal support, and
wherein the extending step comprises: piercing the knife-like edge of each
of the metal members through the thickness of polymeric material following
the embedding step; and wherein the holding step comprising: holding the
metal support, the metal structure, and the metal members in the mechanical
and electrical contact with associated holding means during the electrical
~: I ~ - 7 -
1156:L89
welding step.
By another variant, the step of holding the metal members in the
mechanical and electrical contact comprises: holding the metal members with
associated holding means.
By still another variant, the step of holding the metal members
in the mechanical and electrical contact comprises: holding the metal mem-
bers with components of a standard press.
By a still further variant, the extending step comprises: extend-
ing the metal members made of ferrous metal.
By yet a still further variant, the electrically welding step
comprises: resistance welding employing high electric current flow through
the metal structure, the metal support, and the metal members.
In the accompanying drawings,
FIG. 1 is a fragmentary top plan view of an end portion of a
railway freight car showing a coupler and a coupler carrier thereof and
- 7a -
1 ~56~89
illustrating one exemplary embodiment of an aspect of this invention in a
form of a coupler and coupler carrier and wherein such wear member consists
of a metal support and an attached liner;
FIG. 2 is a fragmentary cross-sectional view taken essentially on
line 2-2 of FIG l;
FIG. 3 is a fragmentary portion of a perspecLive view showing the
metal structure which is embedded within the liner of the wear member of
FIG. 1 prior to embedment thereof;
FIG. 4 is a perspective view with parts in cross section and parts
broken away illustrating the member of FIG. 3 embedded within polymeric ma-
terial to define the liner portion of the wear member of FIG. l;
FIG. 5 is a fragmentary view with parts in cross section and
parts shown schematically particularly illustrating the manner of fixing
the liner of FIG. 4 to a metal support employing an electrical welding sys-
tem,
FIG. 6 is an enlarged perspective view of the wear member of FIG.
1 after fixing of the reinforced liner shown in FIG. 5 to the metal support
thereof and showing support brackets fixed to the exposed surface of such
metal support;
FIG. 7 is a view similar to FIG. 5 illustrating another exemplary
embodiment of another aspect of a wear member during welding of a liner
thereof to an associated metal support --using initially independent metal
members;
FIG. 8 is a view illustrating a typical one of the metal members
which are disposed between the reinforced liner and metal support prior to
welding of such metal members in position.
Reference is now made to FIGS. l and 2 of the drawings which illus-
trate a fragment of an end portion of an exemplary railway vehicle 20. Such
vehicle has a coupler assembly 21 and a coupler carrier 22. As is known in
. .. _ . .. .. . . . . . .. . . ..
.
-- 8 --
: .
, .
1 1561~9
the art, the coupler assembly 21 and coupler carrier 22 are relatively
moveable and thus define what may be considered relatively moveable compo-
nents of the vehicle 20. A wear member in accordance with the teachings of
an aspect of this invention is provided and designated generally by the re-
ference numeral 23. Such wear member is supported by one of the components
21-22 and in this example Lhe ~ear member 23 is supported by the coupler
carrier 22. The wear member 23 protects the components 21 and 22 and in
particular the shank portion 24 of the coupler assembly 21 and coupler
carrier 22 from wear during relative sliding movement thereof.
As seen in FIG. 6 the wear member 23 comprises a metal support,
in the form of a high strength metal plate 25, which is adapted to be sup-
ported on the coupler carrier 22 and a liner 26, as also shown in FIG. 4,
which is attached or fixed to the metal support 25. The liner 26 comprises
an ultra high molecular polymeric material and is attached to the metal sup-
port 25 in accordance with the teachings of an aspect of this invention.
The liner has opposed surfaces 27 and 30 (FIG. 5) wherein the surface 27 is
disposed adjacent the metal support 25. In this example the surface 27 is
disposed against the metal support 25. The surface 30 is a smooth anti-
friction outer wear surface-which is engageable by the shank portion 24 of
the coupler assembly 21. The ultra high molecular weight polymeric material
of the liner is designated by the reference numeral 32 and may be of any
suitable type known in the art. However, preferably such polymeric is an
ultra high molecular weight synthetic plastic material having a molecular
weight of at least two million. Satisfactory results have been obtained
using ultra high molecular weight polyethylene which has a molecular weight
within the range of four to six million.
The liner 26 has a metal structure which is designated generally
by the reference numeral 31 which is embedded substantially centrally, as
shown at 33 in FIG~ 5, between the opposed surfaces 27 and 30. The poly-
1156~89
meric material 32 serves as a matrix for and substantially completely sur-
rounds the Tnetal ST ructure. As will be readily apparent from FIG. 4
- 9 a -
1~56~89
of the drawings, the metal structure 31 has openings 34 therein which
receive the polymeric material 32 completely therethrough as shown at 35.
The openings 34 provide optimum embedmellt of the metal structure 31. Such
structure 31 provides re-inforcement ror and prevcnts cold flow of the poly-
meric material 32.
In ~ccol-(hlnce witll ~he teachill~s of a~ sp(ct of ~his in~cll~ion
the exemplary wear member 23 of FIG. 5 has a plura]ity of metal members
each designated by the same reference numeral 36 which extend between the
metal structure 31 and the metal support 25 through a thickness 37 of poly-
meric material disposed between such metal structure 31 and metal support25 and its associated one of the opposed surfaces. In this example, members
36 extend through surface 27. The wear member 23 has weld means shown as
a plurality of welds 40 welding the metal members 36 in position between the
metal structure 31 and the metal support 25. The welds 40 assure the pro-
vision of a high strength attachment of the liner 26 to the metal support
25. Further, the embedment of the metal structure 31 substantially cen-
tra]ly in the liner 26 provides optimum reinforcement and prevents cold flow
of the polymeric material 32 as described earlier. In addition the manner
in which the welds are provided assures that the surface 30 is a smooth an-
tifriction surface which remains undisturbed and ~mdamaged throughout theattaching operation thereby assuring optimum performance of such surface.
The metal members 36 of the wear member 23 may be defined as part
of either the metal support 25 or the metal structure 310 In this example,
the metal members 36 are defined as part of the metal structure 31. The
metal structure 31 is a single-piece expanded metal structure of a type
known in the art and has a main body 41 which is disposed substantially in
one plane. The main body consists of a grid-like pattern having intercon-
nected integral portions (FIG. 3) with a representative few of such integral
portions being designatéd by the reference numeral 42. The metal members 36
-- 10 --
1 ~56~89
consists of selected ones of the integral portions, sllown at a few typical
locations 43 in FIG. 4, whereby the members 36 may be considered integral
members. Each integral member 36 has one end port~on 45 attached to the
main body 41 and has an opposite end port-ion 44 which cxtends transverse the
main body 41. In this example, each end por~ion 44 extends perpendicular
to the plcnlar main body 41 and as seen in ~TG. 5 welds hO ~eld the terminal
end of each end portion 44 to the metal support 25.
~ le metal structure 31 of this example is shown as an expanded
metal structure having openings 34 therein for receiving polymeric material
therethrough; however, it will be appreciated that the metal structure need
not necessarily be expanded metal structure but may be any suitable metal
structure having openings therein for receiving polymerîc material there-
through to enable better embedment thereof while preventing cold flow of the
polymeric material and with such structure having projections, or the like,
extending therefrom which may be welded to metal support 25, as described.
The wear member 23 is preferably madé in accordance with the
method of an aspect of this invention. Such method comprises certain co-
operating steps which will now be described in detail. In particular, the
method comprises the steps of providing a metal support 25 which is adapted
to be supported; i.e., detachably fastened, on the coupler carrier 22 and
forming the reinforced antifriction pol~rmeric liner 26 with opposed sur-
faces 27 and 30. The surface 27 is adapted to be disposed adjacent (against
in this example) the metal support 25 while surface 30 is a smooth anti-
friction wear surface which remains undisturbed and serves as an antifric-
tion wear surface.
The forming of the liner 26 comprises defining a plurality of
openings 34 in the metal structure 31. In the case of expanded metal
structure, this is achieved by the usual cutting or slitting of a metal
. sheet to define a plurality of spaced parallel slits disposed in a predc-
termined geometric pattern and then pulling opposite side portions of the
1 156~89
sheet perpendicul.ar to the parallel relation of the slits to define the ex-
panded metal structllre. The metal structure 31 is then embedded in ultra
high mol.ecul.ar weight polymeric material e.g. ultra lligh molecular weight
polyethylene havillg moleclllar weigllt of at lteast 2 mill;on using a su:itablemold dev;ce, or the like, as is knowll in the ~irt. T]-~e p~l.yeLhylene serves
.lS a in.ltr:ix ror ~-lnd subs~alltlally completely sul-ro~ ds t-he mtetal structure
31 and simultaneously the walls of the mold device define the opposed sur-
faces 27 and 30 of the polymeric material and liner 26. During the embedding
step the openings 34 receive the polymeric material 32 completely there-
through resulting in better embedment of the metal structure whereby the
structure 31 provides reinforcement and prevents cold flow of the polymeric
material during use of the liner 26 and wear member Z3.
The method of an aspect of this invention includes extending a
plurality of metal members 36, which are an integra]. part of the structure
31, in mechanical and electrical contact between the metal structure 31
and the metal support 25 and through the thickness 37 of polymeric material
32 disposed between such metal structure 31 and meta]. support 25. A suita-
ble elec.trical system, which is designated generally by the reference
numeral 47 in FIG. 5, is operatively connected between the metal structure
31 and metal support 25. The system 47 is operatively connected employing
an electrical cable assembly 50 which has one end thereof suitably connected
to the system 47 and its opposite end mechanically and electrically connec-
ted to the expanded metal structure 31, and as shown at 52, an electrical
cable assembly 51 which has one end thereof suitably connected to the
system 47 and its opposite end mechanically and electrically connected to
the metal support 25, as shown at 53. The electrical system 47 may be of
any suitable type knwon in the art and operates to provide a high electrical
welding current between metal support 25 and a metal structure 31, with the
terminal ends of the end portions 44 of integral members 36 held in
mechanical and electrical contact welds 40 which are provided wllere such
- 12 -
1 156~89
terminal ends engage the metal support 25.
The electrical system 47 is operated to provide the above
described welding action while holding the metal support 25 and reinforced
liner 26 urged together employing suitable holding means. Such holding
means is indicated schematically by arrows 54 and 55 in FIG. 5 of the draw-
ings. Tn es~ence, the holding means 54 and 55 urge the L-erminal ends of the
end portions 45 of the integral mcmbers 36 against ~lle metal support 25
with a predetermined mechanical force or pressure so as to provide a weldillg
action once high current flow is provided by the electrical apparatus 47.
Although the holding means may be any suitable type of device or apparatus
known in the art, such holding means may comprise cooperating components of
a standard press, or the like, which are electrically insulated from the
liner 26 and the metal support 25.
The metal structure 31 is a single- piece expanded metal structure
defined in a grid-like pattern and consisting of interconnected integral
portions having opposite terminal ends. Selected ones of the integral por-
tions are cut away from the main body and each selected integral portion is
bent away from such main body about its opposite terminal end so that it ex-
tends transversely from its main body and preferably perpendicular thereto.
Each of the integral portions 36 is extended through a thickness 37 of tlle
liner 26 and this is preferably achieved while the expanded metal structure
is being embedded during the embedding step.
Another exemplary embodiment of a wear member of other aspects of
this invention is illustrated in FIGS. 7-8 of the drawings. The wear member
illustrated in FIGS. 7-8 is very similar to the wear member 23. Therefore,
such wear member will be designated by the reference numeral 23A and repre-
sentative parts of such wear member which are simi]ar to corresponding parts
v the wear member 23 will be designated in the drawings by the same refer-
ence numeral as in the wear member 23 (whether or not such representative
`- - 1156~89
parts are mentioned in the specification) followed by the letter designa-
tion A. Only those component parts of the wear member 23A which are
different from corresponding parts of the wear member 23 will
- 14 -
1 156189
be designated by a new reference numeral also followed by the letter
designation A and aescribed in detail.
As illustrated in FIG. 7, the wear member 23A consists of a
metal support 25A and a liner 26A which has an e~spanded metal structure
31A suitably embedded therein substantially centrally as shown at 33A
and for sijilar reasons as previously described in connection with the
structure 31 of the wear member 23. The main difference between the wear
member 23A and the wear member 23 is that the wear member 23A has members,
each designated by the same reference numeral 57A, which are used to hold
10 the components 25A and 26A together. The members 57A were initially inde-
pendent members and are disposed between the metal structure 31A and the
metal support 25A and weld means comprising welds 60A are provided at
opposite ends of each of the members 57A to weld the metal components 25A,
31A, and 57A in a high strength manner.
As best seen in FIG. 9 of the drawings, each metal member 57A
has a main body 61A provided with a knife-like edge 62A on at least one
end thereof and the knife-like edge is pierced through the thickness 37A
of polymeric material (FIG. 7) disposed between the metal structure 31A
and the metal support 25A. The liner 26A is made with optimum simplicity
20 by molding or otherwise forming the polymeric matrix 32A around the metal
structure 31Aso that such metal structure is disposed substantially mid-
way or centrally in the polymeric matrix and while defining the planar
parallel surfaces 27A and 30A on opposite sides of the liner 26A.
Once the liner 26A is formed it is suitably disposed in aligned
relation above the metal support 25A as shown in FIG. 8 with the inde-
pendent members 57A disposed therebetween. The previously described
holding means 54 and 55 are then employed as shown in FIG. 7 to urge the
~-15-
1 ~56~89
components 25A and 26A toward each other whereby the knife-like edges 62A
of the metal members 57A pierce through the thickness of polymeric mater-
; ial, as shown. The holding means
- 15 a -
1 ~56189
54 and 55 hold the components 25A and 26A together and thereby hold the
metal support 25A, metal structure 31A, and metal members 57A in mechani-
cal and electrical contact to enable welding thereof. The welding is
achieved in a similar manner as described in connection with the welding
of the liner 23 and it will be seen that the electrical system 47 is em-
ployed for this purpose.
Thus, it is seen that the members 57A are initially independent
members which are extended through the thickness 37A of polymeric material
on the associated side of the expanded metal structure 31A after the liner
26A is formed whereby with this method it is not necessary to provide
cutting and bending of selected integral portions of the expanded metal
structure as was described in connection with the wear member 23. In-
stead, the only requirement in the forming of wear member 23A is the dis-
posal of the members 57A in a predetermined pattern which assures engage-
ment thereof with the metal portions of the expanded metal structure 31A.
In this disclosure of aspects of this invention, the reinforcing
metal structure of each liner 26 and 26A is shown and described as an ex-
panded metal structure; however, as previously indicated such reinforcing
metal structure may be any suitable structure having openings therein
capable of receiving polymeric material therethrough for the purposes
previously described. Further, the reinforcing metal structure should be
such that it provides optimum reinforcement centrally between opposed
planar surfaces of its liner.
FIGS. 5, 6, 7, and 8 of the drawings show expanded metal struc-
ture which is embedded within polymeric material and in each of these
FIGS. a portion of the expanded metal structure extends outwardly from the
end of the polymeric material. This presentation has been made merely
~- - 16 ~
1 ~56~89
to highlight that the expanded metal structure is to be connected with
an electrical welding system. In addition, it is to be understood that
a flat metal plate or sheet used to define the metal support 25 or 25A
may be welded in the manner
- 16 a
1 ~ 56~89
described herein to a sheet of reinforced liner having a corresponding
size and shape whereupon the final configuration of the wear member may be
cut from the above described welded components.
In any event, once the welding action in accordance with this in-
vention has been achieved, expanded metal structure such as shown at the
right hand side of each of FIGS. 5, 6, 7, and 8 is suitably cut away to de-
fine a smooth side edge portion for the resulting wear member, either 23
or 23A.
The wear member of aspects of this invention are preferably pro-
vided with suitable means to enable attachment thereof on the coupler car-
rier 22 and a pair of brackets 63 (FIG. 6) may be provided for this purpose.
In addition, at least one of the brackets 63 may be provided with a locat-
ing projection 65, or the like, for locating the wear member on the coupler
carrier.
The metal support 25 or 25A is preferably a metal plate or sheet
of uniform thickness throughout and free of holes, apertures, or the like.
In addition each support 25 and 25A may be made of ferrous or aluminous
metal. Similarly, the metal structure 31 and 31A and the metal members 57A
may also be made of ferrous or aluminous metal. However, it will be
appreciated that the metal components being welded are preferably the same
type of metal. For example, ferrous metal is preferably welded to ferrous
metal.
The polymeric material has been described herein as being polymer-
ic material of an ultra high molecular weight of at least two million and
preferably such molecular weight is in the range of four to six million.
me preferred technique for determining molecular weight is referred to as
the intrinsic viscosity test and is widely used in the United States.
- 17 ~
