Note: Descriptions are shown in the official language in which they were submitted.
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~'IEI,D OF q'fIE INVENTION
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~ his invention relates to an endless conveyor
including a pulley -for removing particula-te ma-terial
from the inner face of an endless belt conveyor and to ~.
a pulley for such an endless conveyor.
The term "endless conveyor" includes hori~on-tal and
angled conveyors, belt and bucke-t conveyors and any o-ther
like conveyor from which p~rticulate material is to be
removed.
BRIEF DISCUSSION OF TM~ PRIO~ ~T
Thc sil~p:Lest'belt convcyor cons:Lsts o:t' a l~lat endless '.
bc:l.t :lO whlcll passes around two dr~ulls or pu'Lleys known as .,
the head and ta:Ll pul'leys :L:I. an~l ovcr sma:l.:l id.lers 12 as
shown in Flgure :L, The two d:rums have centrally ~ixed
shafts -to allow them to ro-tate9 one of which is rotated
by a source of~power. In use damp or dry particulate
material is carried along the outer-face o~.the top laye:r of
the belt, and material falling to the inner,~ace of the belt
inter~eres with operation and stony material tends to
puncture 'belts and lt ~ets trapped betwoen the belt and
drum.
A pulley'for a conveyor belt adapted -to remove
particulate material from the belt was previously proposed
in prior British Patent Specifica-tion No. 910,801l, In that
prior speci-fication two metal strips are wound spirally
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towards one another about a frame consisting of a central
shaft and a plurality of longitudinal and radial vanes.
However in that proposal the greater proportion of the
circumferential surface of the pulley is represented by
the faces of the strips which confront the belt and there-
1 fore there is a continued danger of part:iculate matexial
béing trapped between the face of a strip and the belt
; causing damage thereto. Moreover, once material is dis-
lodged from the belt, the edges of the strips are too thin
to move material to the outer ends of the pulley in an
efficient manner and the strips tend to slice through the
dislodged material.
SUMM~RY_OF THE P~ESENT INVENTION
In the present invention it is an object to pro-
vide a pulley which presents a leading edge to the belt and
has an area directed inwardly for driving dislodged particu-
late material to an end of the pulley.
According to the present invention we provide a
pulley for an endless belt conveyor comprising a shaft and
a flight wound spirally about the shaft, the 1ight includ-
ing an outwardly directed leading edge or supporting a
belt and an inwardly directed surface portion for driving
dislodged material towards an end of the pulley.
The invention also includes an endless conveyor
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comprising a first and a second pulley abou-t which an
endless conveyor belt may be arranged to pass, the
first pulley consisting of a flighted rotatable element
adapted in use to remove particulate material from the
inside face of a belt. The or each helical flight is
mounted about the rotatable shaft in the manner of a
screw thread.
Preferably the device is located at a position
where the direction of travel of the belt turns throuyh
approximately 180. In such a case the device itself
will form one of the outer pulleys over which the belt
of an endless belt conveyor passes.
The or each flight of the pulley is concentrlc
with the shaft forming the axis of rotation of the pulley
and may be secured directly to the shaft, or on a pipe
mounted concentric with the shaft or on struts spacing
the or each flight away from the shaft. If desired the
periphery of the flight when viewed in a direction per-
pendicular to the axis of the pulley may be convex to :
help centralise the belt on the pulley.
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BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described by way ofexample with reference to the remaining accompanying draw-
ings in which:
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Figure 1 is an isometric view of a simple, con-
ventional belt conveyor.
~`Figure 2 illustrates a three flight embodiment
mounted on struts.
Figure 3 is a side elevation of part of an end-
less conveyor. -
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DESCRIP~ION OF THE PREFERRED EMBODIMENTS
As explained above it is preferable that the de-
vice in accordance with the invention replace an outer pul-
ley of a conventional belt conveyor as shown in Figure 1.
In the drawings a belt cleaning device comprises
more than one helical flight 1 which is mounted about a ro-
tatable shaft 2 in the manner of a screw thread. The number
of helical flights 1 used determines whether the device has
two starting points and is dependent upon the pitch of the
helical flights. The or each flight 1 is wound spirally
about the shaft 2 and includes an outwardly directed lead-
ing edge 20 for supporting a belt and an inwardly directed `
surface portion 21 for driving dislodged material towards
an end of the pulley. The plane of the flight may be at
right angles to the axis of rotation of the pulley or may
be at an angle thereto.
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'Where the pitch of a helical flight is too great
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to support a conveyor belt without distortion to the belt, ~ -
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then more helical flights are added to give sufficient
support to the belt.
In the preferred form of the invention shown in
Figure 2 the flights are supported away from the shaft 2
by struts 5 so that the driving surface portion 21 is re- -
moved from the shaft. Although not illustrated the helical
flights may be mounted on a pipe concentric with the shaft
2-
Figure 3 illustrates a side elevation of part of
a preferred embodiment where particulate material 6 is car-
ried by the upper face o the belt 7. Particulate material
which has been deposited on the inner face of the belt falls
by gravity and i9 led towards an end of the pulley by the
surface portion 21. It will be understood that particulate
material, on reaching the pulley, is kept by gravity between `
the flights the surfaces of which move it in a direction
parallel to the shaft of the pulley until it alls off the
edgé of the belt. The pulley 8 is mounted on a shaft in
bearings 4 (one of which is shown in Figure 3), the bearings
are supported by a frame 9 which also supports idlers 12
one of which is shown.
In use the device replaces a pulley in a conveyor
and as part of a conveyor belt moves upwards around such a
device, any particulate material flows along the heIical -~
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parts in a line parallel to the axis of rotation of khe
device, in a space bounded by a curvecl portion of the belt
and two adjacent sections of the helical flights.
The helical shaped flights can be right or left
handed , to move the particulate material from the belt to
one particular side, or the helical flights of half of the
device on one side of a plane perpendicular to the axis of
rotation can be opposite handed to the helical flights on
the other side of the plane, to move the particulate mater-
ial from the belt to the closest side.
Although not illustrated in the drawings it is
preferred to have the periphery of the pulley Eorming the
cleaning device convex when viewed in the direction per-
pendicular to the axis o the Eirst pulley. The reason
for this is khat the convex shape helps centralise the
belt on the pulley. This may be achieved by providing
spacers (not shown) of different sizes on the pipe to sup-
port the flights in such a way as to give a convex shape.
Alternatively with the supporting struts may increase in
length from the ends to the centre.
In order to avoid the pulley becoming jammed the
gap between adjacent turns of the flight should be greater
than the coarsest particle of the material being conveyed.
Preferably the pulley is about 3" longer than the width of
the conveyor belt so that 1 1/2" of pulley protrudes at
each end.
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Figure 3 to support the flight or flights in such a way
as to give a convex shape. Alternatively wi-th the
embodimen-t of ~igure 4 the supporting struts may increase
in length from -the ends to the centre.
In order to avoid the pulley becoming ja~med the
gap between adjacent turns o-f the flight should be greater
than the coarsest par-ticle of the material being conveyed.
Preferably the pulley is about 3" longer than the width of
the conveyor belt so that 12" of pulley pro-trudes at each
end.
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