COMMISSIONER'S DECISION
Obviousness: Conveyor Belt Cleaning Device
Applicant claimed a belt-cleaning device in the form of a pulley which
comprises a shaft having two auger flights or spirals for cleaning the
belt, wound about the shaft and secured thereto. The rejection was
reversed because the cited art did not teach what was claimed, nor was
the device obvious from that art.
Rejection: Reversed
****************
Patent application 274,857 (Class 198-89), was filed on March 28, 1977
for an invention entitled "Conveyor Belt Cleaning Device." The inventor
is James R. Stoddard, assignor to Stoddard (J.) & Sons Limited. The
Examiner in charge of the application took a Final Action on February 22,
1979, refusing to allow it to proceed to patent.
The application relates to an endless conveyor system including a pulley
arrangement for removing particulate material from the inner face of an
endless belt in the conveyor system. The pulley comprises a shaft having
two auger flights (spirals) wound about the shaft and secured thereto.
More on this system later.
In the Final Action the Examiner refused the application in view of the
following patents because, in his view, the claim fails to define patentable
subject matter.
United States
2,886,169 May 12, 1959 Calder
British
954,741 Apr. 8, 1964 Pates
Canadian
432,607 Jan. 22, 1946 Bevan
In that action he argued that there is no patentable merit in stipulating that
the flights are supported away from the shaft by a plurality of support members.
He went on to say that it is held that the mere use of plural auger flights
over a single auger arrangement is a matter of design expediency only,
and it involves no inventive ingenuity.
In response to the Final Action the Applicant cancelled the claims on file and
submitted new claims 1 to 5. In that response he argued that the amended
claims are properly allowable and not open to the objections made by the
Examiner. He went on to say that the embodiment defined in the amended claims
overcomes the problem of "poor cleaning" of the belts used in the cited art.
He overcomes this problem by providing more than one spiral flight and by
supporting the flights away from the pulley shaft so that there is no trough
formed between adjacent turns of the spiral in which material may build up.
He went on to say:
...
The two main claims submitted with this response for consideration,
are restricted to a plurality of flights of the same hand and it is
believed that the Examiner may well give consideration to these new
claims because the invention disclosed and claimed is a considerable
practical improvement over the previously proposed arrangement.
Although United States patent 2,886,169 shows the basic concept
of the belt cleaning pulley, the new construction now claimed leads
to improved performance and it is respectfully submitted that the
improvements defined in the new claims of record are not obvious
from a reading of British patent 954,741.
...
The consideration before the Board is whether or not the application is directed
to a patentable advance in the art.
As mentioned, the application relates to an endless conveyor including a pulley
arrangement for removing particulate material from the inner face of an endless
belt in the conveyor. Figures 1 and 2, below, show that arrangement:
(See formula 1)
The endless belt is shown at 10, while Figure 2 shows an arrangement which
replaced a normal pulley and illustrates a multi-flight embodiment mounted on
struts 5. It is the object of the device to provide a special pulley
arrangement which presents a leading edge to the belt, and which has an
area directed inwardly for driving dislodged particulate material to one end
of the pulley and away from the system. More specifically, the special pulley
device, for an endless belt conveyor, comprises a shaft having two flights wound
spirally about the shaft and secured thereto. The flights include an
outwardly directed leading edge 20 for supporting a belt and an inwardly
directed surface portion for driving dislodged material towards one end of the
pulley. Amended claim 1 reads:
A pulley for an endless conveyor comprising a rotatable
shaft and a plurality of flights of the same hand wound
helically about the shaft and starting at different
angular positions about the shaft, the flights each being
in strip form supported away from the shaft so as to define
a substantially unrestricted annular clearance about the
shaft, and having a surface portion and a narrower edge
portion, the edge portion being outwardly directed for
supporting a belt of the conveyor during use and the surface
portion projecting inwardly from the edge portion for
driving material dislodged from the belt towards an end of the
pulley.
The patent to Calder describes and shows a pulley for an endless conveyor
comprising a rotatable shaft 2, an auger flight 6 wound helically about
the shaft, the flight being in strip form having a surface portion and a
narrow edge portion, the edge portion being outwardly directed for support-
ing a conveyor belt 10. The surface portion projects inwardly from
the edge portion for driving material dislodged from the belt towards
the ends of the pulley. Figure 1, below, shows that arrangement:
(See formula 1)
Claim 1 of that patent reads:
A belt roller comprising, an elongated shaft having spaced
portions adapted to be supported to permit rotational move-
ment of said shaft,scroll means secured to said shaft to
extend longitudinally thereof between said spaced portions
with at least one end thereof being spaced from said portion
of said shaft adjacent thereto, means secured to said shaft
between said one end of said scroll means and said adjacent
portion of said shaft, and said last mentioned means
comprising a separate paddle extending outwardly beyond
said shaft a greater distance than said scroll means extends
to engage dirt accumulations adjacent said one end of said
scroll means.
Pates describes and shows a conveyor belt pulley comprising a shaft with
helical flights wound about the shaft and supported away from the shaft by
a plurality of support members.
The patent to Bevan shows the concept of incorporating plural helical flights
in a material conveying auger in plows used for removing snow.
On a complete study of the application we find that the combination of the
instant device is clearly novel. For example, the Applicant provides
more than one spiral flight and by supporting the flights away from the
pulley shaft so that there is no trough formed between adjacent turns
of the spiral in which material may build up. The only question remaining
is whether or not there is ingenuity in the invention. It is clear that
the basic concept of a belt cleaning pulley is shown by the Calder patent
and the Applicant has recognized this. The Applicant argues that the
"improved performance" of his device is a patentable improvement and the claims
properly define the scope of monopoly of an invention described in his
application.
We have no reason to disagree with the Applicant when he points out that
a pulley consisting of more than one spiral at any one point gives the belt
much greater peripheral support while moving dislodged material quickly
to the sides of the belt. The Calder patent shows the use of left and
right hand single spiral blade which are secured directly to the pulley shaft.
This, he maintains, tends to allow a build up of material in a "spiral
trough-shaped zone defined by adjacent sections of the spiral blade and the
shaft." The Applicant also argues that, at any point along the pulley
disclosed in Calder, the belt is only supported by one spiral. This is,
as opposed to the present arrangement,which provides for more than one
spiral flight at any one point and by supporting the flights away from the
pulley shaft so that there is no trough formed between adjacent turns of the
spiral. The Pates patent works on a different principle in that the greater
proportion of the circumferential surface of the pulley is presented by the
faces of the strip which confronts the belt whereby particulate material
may be trapped between the face of this strip and the belt.
The Applicant has amended his claims to include the point that the helical
flights start at a different angular position about the shaft. While
this may roughly be shown by Bevan in use with a snow plow, it is new
in the present combination and for a totally different use. Another
feature of the claims is that the flights define an unrestricted annular
clearance about the shaft. This is not shown by the cited art.
To summarize, it is clear that the combination is novel and we are satisfied
that the claims properly define the scope of monopoly of an invention des-
cribed in the disclosure and illustrated in the drawings. It is our
view that the several elements of the claimed combination cooperate to
produce a highly desirable improved result which we believe is not obvious
from the cited references.
We recommend that the decision in the Final Action to refuse the application
be withdrawn.
J.F. Hughes
Assistant Chairman
Patent Appeal Board, Canada
I have reviewed the prosecution of this application and considered the
recommendation of the Patent Appeal Board. I concur with the reasoning
and findings of the Board. Accordingly, I withdraw the Final Action
and return the application to the Examiner for resumption of prosecution.
J.H.A. Gariepy
Commissioner of Patents
Dated at Hull, Quebec
this l5th.day of April, 1980
Agent for Applicant
Ade, Kent & Assocts.
302-211 Portage Ave.
Winnipeg, Man.