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[1995] ZASCA 78
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Roman Roller CC and Another v Speedmark Holdings (Pty) Ltd. (502/93) [1995] ZASCA 78; 1996 (1) SA 405 (SCA); (22 August 1995)
CASE NO 502/93
IN THE SUPREME COURT OF SOUTH AFRICA (APPELLATE DIVISION)
In the matter between:
ROMAN ROLLER CC
1st Appellant
GYULA
LASZLO ROMAN
2nd Appellant
and
SPEEDMARK HOLDINGS (PROPRIETARY)
LIMITED
Respondent
CORAM
: CORBETT CJ, E M GROSSKOPP, NESTADT, VAN DEN HEEVER et SCHUTZ
JJA
DATE OF HEARING
: 5 May 1995
DATE OF JUDGMENT
: 22 August 1995
JUDGMENT
/
CORBETT CJ
:
2
CORBETT CJ
:
This is a patent case with a difference. In 1985 and on
the application of a company known as F A Pressings (Pty) Ltd ("FA Pressings")
patent no 84/3606, entitled "Conveyor Roller and Method of Assembly Thereof"
("the patent"), was registered. The inventor was stated
in the application to
have been Gyula Laszlo Roman. He is now the second appellant and in these
proceedings the admitted infringer
of the patent. In the original application
for a provisional specification made by second appellant (at the time a
shareholder in
and director of F A Pressings) on 13 May 1983 he subscribed the
usual declaration that to his best knowledge and belief, if a patent
were to be
granted on the application, there would be no lawful ground for its revocation.
As I shall show, he now contends that
the patent is invalid and seeks its
revocation. It is common cause that the priority date of the patent is 13 May
1983.
In 1986 the patentee's rights under the patent were
3
assigned to Process Plant (Pty) Ltd, which in turn assigned them to Brelko
Manufacturing CC in 1988. In 1989 and effectively from
8 December 1988 the
latter assigned its patent rights to Speedmark Holdings (Pty) Ltd (respondent on
appeal).
In 1989 the respondent became aware of the fact that a close
corporation, Roman Roller CC (of which the second appellant was the sole
member
and which is the first appellant in this appeal) was manufacturing and disposing
of conveyor rollers which fell within the
scope of certain of the claims of the
patent and thereby infringed the patent. Consequently the respondent instituted
action in the
Court of the Commissioner of Patents, citing first and second
appellants as defendants and claiming interdicts and certain ancillary
relief.
The action was defended by the appellants, who admitted infringement of certain
of the claims in the patent, but (somewhat
remarkably) denied the validity of
the patent and counterclaimed for its revocation on the grounds that the
"invention" was not new,
that it was obvious, and
4
consequently did not involve an inventive step, and that its claims were not
clear.
The case was tried by MacArthur J, sitting as a Commissioner of
Patents. At the inception of the trial the appellants formally abandoned
the
defence and ground of revocation based on lack of novelty. MacArthur J found
against the appellants on the remaining issues of
obviousness and clarity,
granted the relief prayed by the respondent and dismissed the counterclaim with
costs. He further granted
leave to appeal to this Court. (The judgment of
MacArthur J has been reported: see
Speedmark Holdings (Pty) Ltd v Roman
Roller CC and Another
1993 BP 397.)
On appeal counsel appearing on behalf of the appellants advanced the same two
grounds of invalidity and revocation. Before dealing
with them, I shall describe
the patent in more detail.
5
The Patent
Under the heading "Background to the Invention", the
body of the specification opens with the words -
"THIS INVENTION relates to conveyor tellers or rollers of the type adapted to
support conveyor belts used in mining, industrial and
like applications."
As this quotation indicates - and as was confirmed in evidence -"idlers" and
"rollers" are alternative terms for the same thing. The
specification then
proceeds (I have for convenience of reference numbered the quoted passages from
the specification):
"1. Conveyor rollers generally comprise a rigid sleeve or drum which is
rotatably mounted by means of suitable bearings on a shaft,
the shaft being
supported in a cradle or frame which in turn is mounted to a foundation.
Generally the sleeve is formed from a steel
tube. Problems with steel or metal
sleeves occur when the idler jams due to . bearing seizure or for other reasons.
When this
6
occurs, the belt runs over a stationary idler causing
the steel sleeve to heat up and wear away, resulting
in the belt being damaged.
2. Other problems arise when the conveyor is carrying uneven loads which form a
protuberance on the underside of the belt which impinges
on the conveyor idler
as the protuberance passes over the idler. This can cause denting of the sleeve
as well as jolting and possible
damage to the bearing assembly.
3. Further problems with conventional rollers occur because the outer surface of
the sleeve is not absolutely concentric with the
axis of rotation. Rotation of
an eccentric roller causes rapid deterioration of the bearing assembly as well
as the setting up of
harmonic vibrations in the belt. Also, because the steel
sleeve is smooth, the belt will tend to 'wander' relative to the idler which
is
considered undesirable."
The
specification then describes attempts to alleviate "at least some" of these
problems. These attempts have consisted in the
7
development of conveyor idlers formed of or having an outer cover
of
rubber or soft plastics, which absorbs some of the shocks to which
the
idlers are subjected. In this connection certain British patents
are
referred to, more particularly British patent no 1076499 which
describes a roller having a cylindrical drum covered with a "rubber
sleeve". But with rubber or "like synthetic plastics materials such as
polyethelene" there are, according to the specification, other problems
in that -
"4. . . . once the roller jams, the relative movement between belt and
stationary roller causes rapid breakdown of the cover, eventually
leading to
damage to the belt. Also, such materials tend not to be dimensionally stable,
and as soon as an eccentricity occurs in
the roller, further rotation causes
rapid deterioration of the eccentric condition."
The specification states that the object of the invention is to provide a
conveyor roller which runs smoothly and which has
8
superior wear or operational characteristics "in at least some applications".
The invention is described thus:
"5. According to the invention there is provided a conveyor roller comprising
a drum rotatably supported on a shaft by a bearing assembly,
the drum comprising
a right circular cylindrical tubular inner sleeve formed of metal, and a coaxial
right circular cylindrical outer
sleeve formed of a hard, wear resistant,
plastics material.
Preferably the hard plastics sleeve will be self supporting and the metal
sleeve will be formed of thin steel tube.
6.
Further there is provided
for the plastics material to have self lubricating characteristics. Specifically
it is envisaged that the
plastics material will have physical characteristics
similar to that of rigid polyvinyl chloride (rigid PVC), polypropylene, or high
density polyethelene.
7.
Further there is
provided for the outer surface of the drum to be machine turned such that the
axis of the outer surface is concentric
with the axis of rotation of the roller.
During turning a
9
fine helical groove or a plurality of concentric circular grooves may be cut
into the outer surface of the plastics sleeve, along
substantially the entire
length of the sleeve. The fine groove will not materially affect frictional
resistances to movement tangentially
to the sleeve but will increase frictional
resistance to movement parallel to the axis of rotation of the idler.
8.
The bearing assembly by
means of which the drum is supported on the shaft may comprise a pair of roller
bearings preferably mounted
in end caps formed of a hard plastics material. The
plastics material of the end caps may be a nylon 66 derivative and will
preferably
be moulded to the required shape. The shape may include a ribbed
formation.
9.
It is envisaged that the
plastics material of the sleeve will have characteristics substantially as
follows:
Mass density: 1350 - 1460 kg/m3
heat reversion: less than 3.0%
specific heat capacity: 0,85-2.10 kJ/kg
0
C
vicat softening point: 82 - 85
10
tensile strength @ 20° C: 56 MPa (at yield) modulus of elasticity: 3,2
GPa comprehensive strength: 80 MPa"
(It was common cause that the word "comprehensive" was an error and should
read "compressive".)
"10. Further there is provided for the polymeric sleeve to comprise a length
of rigid PVC piping which during assembly of the idler
is heat shrunk onto the
metal sleeve. This material is suitable as it has a low coefficient of friction
with a conveyor belt.
11.
It will also be possible
for the plastics sleeve to have electrically conductive particles interspersed
therethrough which will assist
in reducing electrostatic buildup on the roller
in use.
12.
The end caps may be press fitted
into the drum or alternatively may be screwed into thread formations formed on
the inner surface
of the drum."
The
specification then proceeds to describe a method of
11 assembling such a conveyor roller. This consists essentially of what
is referred to as heat-shrinking (see passage 10 above). The plastic
outer
sleeve is heated to a condition of "slight plasticity"; the inner
(steel)
sleeve and the outer sleeve are placed end-to-end in a coaxial
relationship;
the outer sleeve is urged over the inner sleeve so that
they form a single
composite drum; and the composite drum is then
allowed to cool. Other methods described relate to the shaving of the
outer surface of the outer sleeve to achieve concentricity; the cutting
of circular or helical grooves into the outer surface of the outer
sleeve;
and an hydraulic ram for urging the outer sleeve over the inner sleeve.
The specification includes certain drawings, which are fully described in the
body of the specification and descriptions of preferred
embodiments of the
invention. I shall return to some of these descriptions later.
The specification concludes with 20 claims, of which seventeen are product
claims and three are method claims. The
12
claims in issue in this case are nos 1,7,8 and 15. The attack upon the
validity of the patent is concentrated on claim 1. Claims 7,
8 and 15 are
dependent on claim 1 and consequently they stand or fall by the validity of
claim 1.
Claim 1 (as amended in September 1989) reads as follows:
"A conveyor roller comprising a drum rotatably supported on a shaft by
bearing assemblies near respective ends of the shaft, the drum
comprising a
right circular cylindrical tubular inner sleeve formed of metal, and coaxial
right circular cylindrical outer sleeve
formed of a hard, wear resistant,
plastics material, each bearing assembly being mounted in an end cap which is
fitted into the drum,
each end cap comprising a cylindrical body within which a
bearing assembly is received and having a radially extending lip which
overlies
the end of the inner sleeve."
As I have indicated, the attack upon the validity of
the
13
patent is two-pronged: (1) obviousness and (2) lack of clarity. I shall deal
with these in turn. At this stage it is appropriate to
point out that the onus
of establishing invalidity on either of the grounds alleged rests on the
appellants (
Gentiruco A.G. v Firestone S.A. (Pty) Ltd
1972 (1) SA 589
(A), at 629 E - F).
Obviousness
Sec 25(1)
of the
Patents Act 57 of 1978
("the
Act")
>provides that, subject to certain limitations and exclusions (none of
which is here relevant), a patent may be granted -
"... for any new invention which involves an inventive step and which is
capable of being used or applied in trade or industry or
agriculture."
According to
sec 61(l)(c)
of the
Act a
person may apply for the revocation of
a patent on the ground, inter alia -
. . . that the invention concerned is not patentable
14
under
section 25".
And, in terms of
sec
65(4)
of the
Act, in
any proceedings for infringement the defendant may
counterclaim for the revocation of the patent and, by way of defence, rely upon
any ground on which a patent may be revoked.
One of the requirements of
patentability prescribed by
sec 25(1)
is that the new invention must involve "an
inventive step". The meaning of this term is defined by
sec 25(10)
, the relevant
portion of which reads:
"... an invention shall be deemed to involve an inventive step if it is not
obvious to a person skilled in the art, having regard
to any matter which forms,
immediately before the priority date of any claim to the invention, part of the
state of the art by virtue
only of subsection (6). . . "
Subsection (6) provides:
"The state of the art shall comprise all matter
15
(whether a product, a process, information about either, or anything else)
which has been made available to the public (whether in
the Republic or
elsewhere) by written or oral description, by use or in any other way."
As
sec 25(1)
indicates, an invention is deemed to involve an inventive step
if it is not obvious to a person skilled in the art, having regard
to the state
of the art at the relevant time. Conversely, if the invention is obvious to such
a person, then the invention is deemed
not to involve an inventive step and to
be invalid on the ground of obviousness.
In order to apply these provisions to a particular case it; is necessary
first to determine (i) what the art is to which the invention
relates, (ii) what
the state of this art was at the relevant time and (iii) who is to be regarded
as a "person skilled in the art".
These were matters in dispute, both before the
Commissioner and before us.
16
The Relevant Art
At this point it is pertinent to make some reference to the evidence adduced
in the Court a quo. Three witnesses testified. They were,
in order of
appearance, Mr Frittella, an expert called by appellants, Mr Roman (the second
appellant), the original inventor, and
Mr H W Read, respondent's expert.
Although an expert summary in respect of second appellant was filed, his
evidence was mainly factual
and consisted of description of how he came to hit
upon the invention which he patented in 1983 and of an explanation (given, it
would seem, with a measure of embarrassment) of his later viewpoint (i e after
receiving a summons for patent infringement) that
the patent was invalid. His
description of how the invention came about merits repetition. At the time he
was engaged in the manufacture
of steel rollers and was seeking business with
"the mines". A visit to a mine revealed to him quantities of steel rollers, some
of
them still "brand new", which had been scrapped. Someone at the mine told him
that
17
if he could "do something which is better" he would be "in business". He went
back to his workshop and began experimenting with different
types of materials.
In his own words, he first of all -
"took an ordinary steel roller and ask a person to cover it with fibreglass.
We have it tested and it did not work. Then I see a water
pipe lying just around
in my workshop and I thought about that you know, if I could get these in
different sizes, I could use it
as a coat for the steel roller. So I looked
around and I find a suitable water pipe which we called at the time, made out of
plastic
that I shrink onto the steel pipe. Then it put it to tests and it did
work for a short time. Then I went to John and Kemick and I
wanted to get some
advice if this idea of mine can be patentable or protected or something to
protect it with. There they advised
me to patent the thing first or take a
provisional out and then we will deal with the rest"
As to the scope of the art in question, Messrs Read and Fritella disagreed
with one another. Mr Read drew a distinction
18
between what he termed "belt conveyor rollers", i e rollers which supported
and propelled a conveyor belt (upon which the goods to
be moved were placed),
and "cargo rollers", i e rollers upon which cargo is conveyed without the
intervention of a belt; and he expressed
the view that the relevant art was
confined to belt conveyor rollers. In this connection he pointed to various
design considerations
which differentiated between these two types of rollers;
and also to the fact that the opening words of the specification make it
clear
that the invention relates to rollers of the type adapted to support conveyor
belts (see quotation above). Mr Frittella, on
the other hand, expressed the view
that this distinction was not a valid one. According to him the functions
performed by belt conveyor
rollers and cargo rollers might differ, but the basic
engineering concepts required in both their design and their manufacture were
similar. He defined a roller as a cylindrical element which by its rotating
motion allows the actual movement of a load. In his expert
summary (which he
confirmed in
19
evidence) Mr Frittella defined the art in question thus:
"The art involves rollers with or without belts and includes for example,
rollers for conveying material in the mining industry and
rollers, with or
without belts, for the conveyance of materials in other industries, e.g. cargo
conveying."
He conceded, under cross-examination, that the patent related only to belt
conveyor rollers, but contended that this did not contradict
his evidence about
the scope of the art.
In the Court below the Commissioner dubbed the distinction an "artificial"
one and investigated the state of the art on the basis
that it included both
belt conveyor rollers and cargo rollers (see reported judgment pp 404 G - 405 B,
406 G-407F).
On appeal respondent's counsel sought to persuade us that the Commissioner's
findings in this regard were incorrect and that the art
was confined to belt
conveyor rollers. I am not so persuaded. It seems to me that respondent's
contention fails to distinguish the
art to
20
which an invention relates and a particular application within the scope of
that art. At all events, as I shall show, this dispute
is not of crucial
importance in this case.
The State of the Art
In order to establish the state of the relevant
art immediately before the priority date, viz 13 May 1983, the appellants
pleaded
and produced some fourteen published documents. It is not in dispute
that these documents were available to the public before the
priority date. Only
ten of these documents were referred to in evidence and I do not think that the
remaining four take the appellants'
case any further. Apart from one (a pamphlet
referred to as Hewitt-
Robins), the ten documents are all patent specifications emanating from
various countries - Germany, the United Kingdom, the Republic
of South Africa
and the United States of America. One of these specifications (referred to as
Agfa) relates to rollers used in
21
photographic development tanks. These are not conveyor rollers and it
seems to me that the Agfa document falls outside the scope of
the art. (Cf the
reported judgment of the Commissioner, p 409 F-G.) , The same would seem to
apply to the document referred to as
Wittler, a German patent for the
broad-drawing of flexible continuous sheet materials, particularly textiles.
This leaves the following
documents which do relate to either belt conveyor
rollers or cargo rollers: the McCullagh, Halbron, Thompson, Fyson, Vom Stein and
Gruber specifications. In addition, in argument before us the appellants relied
on another transport roller specification, referred
to as Fototechnik (though
this was not referred to in the evidence adduced by appellant). The
Hewitt-Robins pamphlet was also relied
upon by the appellants, but from the
limited information contained in this document it is not possible to say what
the purpose of
the roller depicted therein is and I leave it out of account.
22
The Skilled Addressee
Appellants contend that the notional person skilled in the art to whom the
specification should be taken to be addressed is a fitter
and turner or artisan.
The respondent, on the other hand, though initially contending that the skilled
addressee is an engineer,
indicated in the course of argument (through its
counsel) that it was prepared to abide by the conclusion of the Court a quo
which
was as follows (see reported judgment, at 406 D-G):
"As far as the present matter is concerned, the alleged invention does not
appear to be particularly sophisticated. Having heard the
evidence of Fritella
and Read, I would assess it as being fairly low down in the technology scale and
certainly not requiring skills
of a graduate engineer to comprehend and
understand it. However, the characteristics of the plastics material from which
the outer
sleeve of the roller is made may make it difficult for a skilled
journeyman to understand fully. The physical properties of the plastics
material
set out in the specification and claims are
23
elaborate and consequently, my inclination is to say that the skilled
addressee in this case is slightly more qualified than the ordinary
artisan. I
would categorise him as a designer-draughtsman who is acquainted with workshop
techniques but such a person does not necessarily
have to be a professional
engineer"
I am broadly in agreement with this. As I shall show, a central feature of
the invention in this case is the hard plastic outer sleeve
which encases the
roller and it seems to me that the skilled addressee should be someone whose
expertise includes a knowledge of
plastics technology.
A Step Forward?
I turn now to the question whether,
in the light of the
state of the art as it was immediately prior to 13 May
1983, the
invention claimed in the patent constituted a step forward. In
order to
answer this question it is necessary to analyse the invention and
to
24
compare it with the state of the art as revealed by the documents to
which I have referred. Essentially the enquiry relates to claim 1, which, it
was agreed, comprises the following integers:
(a)
A conveyor
roller
(b)
comprising a
drum
(c)
rotatably supported on a
shaft
(d)
by bearing
assemblies
(e)
near respective ends of the
shaft
(f)
the drum comprising a right circular
tubular inner sleeve
(g)
formed of
metal
(h) and a coaxial right circular cylindrical
outer sleeve
(i) formed of a hard, wear resistant, plastics material
(j) each bearing assembly being mounted in an end cap
(k) which (end cap) is fitted into the drum
(1) each end cap comprising a cylindrical body
(m) within which a bearing assembly is received
25 (n) and having a
radially extending lip
(o) which overlies the end of the inner sleeve.
It is, I think, common cause that none of the state of the
art documents relied on by the appellants describes a conveyor roller
with
all the above-listed integers. It is also common cause that, apart
from
integers (f), (g), (h) and (i), all the above integers are to be
found
individually in one or more of these documents. According to
respondent, what
is new about the invention in suit is the combination
of (i) a right circular tubular metal inner sleeve (integers (f) and (g)
)
and (ii) a coaxial right circular cylindrical outer sleeve formed of
a
hard, wear resistant plastics material (integers (h) and (i)) to form
the
drum component of the roller. In the context of these integers "right"
means that the end of the tube or cylinder is at right angles to the axis
thereof; and "co-axial" I take to mean having a common axis of
rotation. There was much debate concerning the meaning of the word
"sleeve", appearing in integers (f) and (h). I shall come to this later.
26 ' Of the state of the art documents, those referred to
as
McCullagh, Halbron, Fyson and Vom Stein do not
disclose a drum
consisting of an inner and outer sleeve. Thompson describes
an inner
metal tube and an outer "tire" of elastomeric or plastic material,
which
has been injection-moulded onto the inner tube. Gruber, which
is
referred to in the body of the patent in suit, describes an outer
sleeve
of rubber which is pulled onto the roller. And Fototechnik, which
was strongly relied upon by appellants in oral argument before us,
reveals a transport roller comprising a metal pipe having a synthetic
material "sleeve". The body of this specification indicates that this
"sleeve" should be composed of -
"a thermoplastic synthetic material, eg of rigid PVC, compact grained
polyamide, polypropylene, polyethylene, or a mixture of the
said materials;
it
,may be extruded, cast or injection-moulded on to said roller".
Appellant's reliance on Thompson and Fototechnik raises the question
27
of the meaning of the word "sleeve" in the patent in suit and whether it can
consist of a layer which is superimposed by, for example,
extrusion, casting,
coating or injection-moulding. Reference was made by the expert witnesses to the
Chambers Dictionary of Science and Technology
. This work defines "sleeve"
(in the engineering context) as -
"a tubular piece, usually one machined externally and internally".
This accords with other dictionary definitions:
"A tube, or hollow shaft, fitting over or enclosing a rod, spindle, etc., and
designed to protect or strengthen it, or to connect
one part with another
(Oxford English Dictionary,
sv "sleeve", meaning 7.b.)
"A tubular part designed to fit over another part".
(Webster's Third New
International Dictionary,
sv "sleeve", meaning 2a.)
28
If reference be made to the body of the specification, it, in my opinion,
provides a clear indication as to what is meant in claim
1 by the word "sleeve".
This is to be found particularly in the passage 10 (quoted above) which
describes the polymeric sleeve as
comprising "a length of rigid PVC piping"
which during the assembly of the roller is "heat shrunk" onto the metal sleeve;
and in
the directions given in regard to the assembly of the roller, involving
heating, the placing of the inner steel sleeve and the outer
plastic sleeve
end-to-end and the urging of the latter over the former to form a single
composite drum. Indeed, once one has separate
tubes to be asssembled coaxially,
a method of the kind described is necessarily implicit in claim 1 of the
patent.
In evidence (given mainly with reference to Thompson) Mr Fritella tried
valiantly to substantiate the proposition that in relation
to a conveyor roller
a "sleeve" just meant "a covering of sorts", including a coating or lagging or a
sheath. Under cross-
29
examination, however, he was forced to concede that this definition of his
did not accord with either the definition in
Chambers
or the definition
to be deduced from the patent specification itself. MacArthur J rejected Mr
Fritella's evidence on this point (see
reported judgment, at 408 D-G); and, in
my opinion, he was correct in doing so.
It is true that Fototechnik speaks of a synthetic material "sleeve", which is
extruded, cast or injection-moulded onto a metal pipe
to form the drum of the
roller. But this document was not properly considered in evidence. The
appellants did not refer to it at
all (until it came to oral argument on
appeal): and in his evidence Mr Read referred to it only in connection with
integers (n) and
(o). The original document is in German and uses the word
"Ummantelung", which has been rendered "sleeve" in the English translation
before us. Because the matter was not canvassed it is not possible to say how
accurate this translation is. In any event, the point
at issue is the
30
meaning of "sleeve" in the patent in suit and I fail to see how this can be
materially influenced by the wording of another patent.
Mr Read adopted the
dictionary meanings of "sleeve" and, in so far as his evidence is admissible in
this regard, it would seem to
be acceptable. Accordingly it is clear that
neither Thompson nor Fototechnick establishes that integers (f), (g), (h) and
(i) - and
more particularly (n) and (i) - were part of the state of the art in
1983. And indeed Mr Fritella conceded that, giving "sleeve"
this meaning, a hard
plastic outer sleeve over a steel inner sleeve was "not to be found in the
documents".
In all the circumstances, I am, therefore, of the opinion that the patent
does disclose a step forward.
An Inventive Step?
The next and final question in regard to the issue
of obviousness is whether the patent involves an inventive step. This
31
must be judged by asking oneself whether, in the light of the state of
the art at the time, the step forward taken by the invention
would have been
obvious to the skilled addressee. Simplicity is no obstacle. Experience has
shown that a number of simple inventions
have, constituted patentable subject
matter. Moreover, one must guard against the snare of hindsight, while at the
same time not
over-compensating for this factor.
In this regard relevant evidence was given by Mr Read, an engineer with some
twenty years experience in the mining industry. He had
been intimately involved,
in the course of his employment by several different mining corporations, with
the operation, maintenance,'
design, procurement and construction of conveyor
systems, including the conveyor belts and the rollers comprising them. In 1986
he
left his then employer, Gencor Limited, and formed his own company, but
continued to be involved with conveyor systems.
Mr Read stated in evidence that prior to 13 May 1983
32
there were a number of problems relating to belt conveyor rollers. Rollers
with all-metal drums were heavy and had high inertia; they
were subject to wear
and corrosion; in the event of the failure of an individual roller, there was
the danger of damage to the belt,
an expensive component of the conveyor system;
and the machining of metal drums to achieve concentricity was expensive and
rarely
done. (Cf passages 1, 3 and 4 of the specification in suit quoted above.)
An attempt was made to overcome these problems by providing
a rubber outer
sleeve, but this did not work. (Cf passage 4 above.) There were numerous
products on the market with coatings, but
they became delaminated and did not
last. Eventually in about 1985 he encountered the rollers made under the patent
by, presumably,
F A Pressings. Asked about his reaction to this product Mr Read
stated:
"When we looked at it we thought it had possibilities. We then tried it and
we were really over the moon with the results. It worked
very
33
well."
Mr Read elaborated by explaining how reliable the plastic sleeve was, how
well it lasted and how it did not come loose. On the longer
belts the lower
inertia was important and reduced belt tensions. The outer sleeve protected the
roller from corrosion; there was
superior concentricity and grooves machined in
the plastic surface of the drum helped to prevent wander. (Cf passages 5 and 7
above.)
Mr Fritella did not really dispute this evidence. He in fact had never
worked on the mines.
It would seem, too, from the evidence that the use of PVC or other forms of
wear resistant plastic piping, which is manufactured for
other purposes as well,
would be cheaper than a process involving injection moulding.
Under cross-examination it was suggested to Mr Read that the invention was
obvious. He replied:
34
"If it was so obvious, why did we have to wait so long before somebody did
it? We battled and we had major problems."
On the issue of inventiveness the Commissioner expressed his conclusion thus
(see reported judgment, at 411 E-G):
"The invention, albeit simple in concept, is a commercial success and the
hard sleeve does overcome many of the problems encountered
in these rollers and,
at the priority date, namely 13 May 1983, no-one had ever produced a roller with
this combination of integers
including an outer sleeve of hard, wear resistant
plastics material. The submission that all this is obvious is, I believe, a case
of being wise after the event. I am satisfied that the step forward was
inventive and this ground of opposition must fail not only
in respect of claim 1
but also for the other claims."
I agree. Appellants' attack upon the validity of the patent on the ground of
obviousness accordingly fails.
35
Lack of Clarity
It is a ground for the revocation of a patent, and
also a defence in an action for infringement -
"... that the claims of the complete specification concerned are not . . .
clear . . ."
(See 61(l)(f)(i), read with
sec 65(4)
, of the
Act.) This
ground of
invalidity/revocation is sometimes referred to as "ambiguity". It is the duty
of a patentee to state clearly and distinctly the nature
and limits of his
claim: to define his monopoly. Only if this is done will others know exactly
what they may do and what they may
not do. The degree of clarity required is
that which leads to "reasonable certainty".
In determining whether a patent claim stakes its monopoly with a sufficient
degree of clarity, the Court must view the patent through
the eyes of the
skilled addressee in the relevant art; and the
36
Court must take into account that such addressee is expected to use
reasonable skill and intelligence in interpreting the language
of the patent. He
is not required to struggle unduly with it, but he must make the best of it and
not adopt an attitude of studied
obtuseness. If words or expressions in a claim
are affected or defined by what is said in the body of the specification, the
language
of the claims must be construed accordingly. Moreover, uncertainty or
ambiguity in a claim may be resolved by what appears in the
body of the,
specification, which may be thus resorted to not only when the language in
question has been expressly defined in the
body of the specification, but also,
in the absence of such definition, where there is material in the body from
which the intention
of the draftsman can be gathered. Where the words permit it,
an interpretation should be adopted which is consistent with the description
of
the problem to be overcome and the method of doing so described in the body of
the specification. Another source of elucidation
of apparently unclear
37
language may be the prior art itself. (See generally
Helios Limited v
Letraset Limited
(1970) BP 495 (T), at 498 G - 499 B, 500 B - G, 503 B -C;
Letraset Ltd v Helios Ltd
1972(3) SA 245 (A), at 249 H - 251
B.)
Sometimes a patentee uses general or flexible language where he could
have set forth mathematical limitations to define his claim,
or one or more of
the integers thereof. Here I agree with Colman J (delivering the judgment of the
Full Bench of the Transvaal Provincial
Division in
Helios Limited v Letraset
Limited,
supra) when he said (at p 499 C-F) that a claim whose integers are
defined in terms of mathematical limits may be circumvented by
a person who
varies his dimensions so as to take his article outside the inventor's
prescribed limits, but who makes substantially
what is claimed in the patent;
and that consequently the use of flexible language may be justified even where
it is possible to impose
mathematical limits. As Colman J put it (at 499 D):
38
"It is . . . often possible for an inventor to limit the scope of one or more
of the integers in his claim by setting forth mathematical
limitations; but in
some cases the adoption of that expedient will leave doors open which the
inventor is entitled to close."
(See also remarks of Lord Shaw of Dunfermline in
British Thomson-Houston
Company Ld v Corona Lamp Works Ld
(1922) 39 RPC 49
(H.L.), at 90, lines 8 -
26.) Moreover, the mere fact that simple, non-inventive test trials or
experiments may be necessary in order
to ascertain whether a particular item
falls within the ambit of a patent or not, will not invalidate the patent
(Helios Limited v Letraset
Limited, supra, at 502 A; cf
British
Thomson-Houston
case, supra, at 81, lines 8-16).
With these principles in mind, I turn to the patent in
suit.
Appellants' attack upon its validity focused on the use of the
word
"hard" in integer (i); and it was argued that this introduced a
fatal
39
measure of ambiguity in claim 1, and consequentially in claims 7, 8 and
15 as well.
The ordinary dictionary meaning of "hard" is -
"That does not yield to blows or pressure; not easily penetrated or separated
into particles; firm and resisting to the touch; solid,
compact in substance and
texture"
(Shorter Oxford English Dictionary,
sv "hard", meaning 1.1.)
Thus, in a general sense there is no difficulty about the meaning of "hard".
More specifically, however, there is because "hard" is
a relative term: there
are different degrees of hardness. Does this pose a real problem in the present
case? I do not think that
it does.
There are, in my opinion, two sources from which the skilled addressee (who,
it will be recalled, is endowed with a knowledge of plastics
technology) would
be able to ascertain with' reasonable certainty what integer (i) means when it
speaks of -
40
"... a hard, wear resistant, plastics material. . ."
The first of these sources is the body of the specification itself. Here a
clear indication is given of the type of plastics material
which is regarded as
"hard" and "wear resistant". I refer in this connection to passage 6 (quoted
above) which states that it is
envisaged that the plastics material will have
physical characteristics similar to rigid polyvinyl chloride (PVC),
polypropylene
or high density polyethelene. In passage 10 there is again a
reference to rigid PVC piping. In the portion of the specification devoted
to a
detailed description of the drawings it is again stated that it is envisaged
that the outer sleeve -
"... will be formed of a rigid polyvinyl chloride (uPVC), high density
polyethelene, or polypropelene. Other materials which may be
used are a suitable
Zytel (a Dupont product). Preferably the outer sleeve will be formed of a
plastics material which is sufficiently
wear resistant
41
to withstand the rigours of use as a conveyor roller, and will not be
brittle."
The physical qualities referred to in passage 9 do not apparently measure or
reflect hardness; or at any rate it was not shown that
they did.
The second
source which the skilled addressee would be able to utilise in interpreting
integer (i) would be hardness tables, referred
to as the Rockwell hardness test
and the Shore hardness test. These were referred to in Mr Read's expert summary;
and also dealt
with in evidence by both Mr Fritella and Mr Read. Mr Fritella
testified that a fitter and turner would not know these tests, but
in view of
the finding that the skilled addressee would not be a mere fitter and turner
this evidence is beside the point. Under
cross-examination he agreed, with
reference to the Rockwell and Shore scales, that there were accepted engineering
principles with
regard to the testing of plastics for hardness. Read dealt
extensively in his evidence with the
42
Rockwell and Shore scales and the recognised tests for measuring
hardness of plastic materials.
In his oral argument in reply appellants
counsel submitted that respondent was not entitled to rely upon these hardness
scales because,
so he said, it had been agreed between the parties that there
were no words or phrases used in the specification which bore "a special
technical meaning". Appellants' counsel made a statement to this effect in his
opening address and it was not at that stage contested
by counsel for the
respondent. There is no substance in this point. Appellant's counsel fully
canvassed the hardness scales in the
Court a quo. I am not persuaded that
respondent's counsel agreed to anything which would preclude reference to the
hardness scales.
And, in any event, I do not think that it is a question of
giving a word a special technical meaning. The hardness scales simply
represent
part of the , technical equipment and know-how which the skilled addressee would
have when called upon to interpret and
apply claim 1 of the patent.
43
I do not propose to go into detail with reference to the application of the
hardness scales. Suffice it to say that the plastic materials
referred to in the
body of the specification figure on these scales and that I am satisfied that,
armed with these scales and, if
necessary, with the benefit of some simple
testing or experimentation, the skilled addressee would have little difficulty
in deciding
the meaning of "hard" (in the context of claim 1) in relation to
other plastic materials. This is a typical case where the adoption
of
mathematical limitations could have left the doors wide open to the patentee's
competitors and the failure to define "hard" in
mathematical terms is, in my
opinion, not fatal to the validity of the patent.
For these reasons, I hold that the appellants have failed to establish that
claim 1 is lacking in clarity.
The appeal is dismissed with costs.
M M CORBETT E M
GROSSKOPF JA)
NESTADT JA) VAN DEN HEEVER JA) CONCUR SCHUTZ JA)