Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE
"MOUNTING FOR A CONVEYOR BELT SCRAPER"
FIELD OF THE INVENTION
This invention relates to a mounting for a
conveyor belt scraper.
SUMMARY OF THE INVENTION
According to the invention, there is provided a
mounting for a belt scraper of composite construction
comprising an assembly of components to permit displacement
of the scraper during normal running movement of the belt in
one direction when an obstruction projecting from the belt
strikes against the scraper, the mounting including biasing
means adapted to bias the scraper towards the belt, and
further including displacement means adapted to pivotally
displace the scraper against the bias of the biasing means
away from the belt when an obstruction projecting from the
running belt strikes against the scraper, the biasing means
being provided at the pivot axis of the displacement means.
The obstruction may be an object held fast with
the belt and protruding therefrom, e.g., a piece of rock, or
a belt joint, or a bolt or screw, etc.
The displacement means may include a lever arm
having at its one end, a formation in which a shaft
supporting the scraper may be secured, and being pivotally
mounted, at its other end, so that the lever arm can execute
an arcuate movement about its pivotal mounting.
The member for securiny the shaft of the scraper
may be of annular configuration so as to receive the shaft
therei~. Screw-threaded bolts may be provided to be screwed
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through the annul ar formation onto the shaft to secure the
shaft therein.
The biasing means may be an assembly including a
shaft of angular cross-section mounted within an angular
sleeve with pads of elastic material, such as natural or
synthetic rubber, interposed between the shaft and the
sleeve. Thus, when the shaft is turned inside the sleeve,
the elastic pads are compressed, thereby generating bias in
the form of torque tending to return the shaft to a neutral
position.
Alternatively, the biasing means may comprise a
spring, e.g., a lever spring or a torque spring.
The biasing means is provided at the pivot axis at
the pivotally mounted end of the lever arm. Thereby the
bias stored in the biasing means is transmitted through the
lever arm to the scraper by applying torque to the lever arm
at its pivot axis.
The bias generated in the biasing means may have a
predetermined value of a sufficient magnitude to ensure that
the scraper is only displaced when an obstruction of a
predetermined size or rigidity on the running belt strikes
against the scraper.
A removable and adjustable stop may be provided
for adjusting and limiting the arcuate travel of the lever
arm, when predetermined blade wear has taken place.
The mounting may further include a sleeve to which
the biasing means may be secured. By means of the sleeve,
the mounting may be fitted in an operating position. It may
for e~ample be fitted by sliding the sleeve over a shaft and
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screwing nuts onto the shaft against each axial end of the
sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is now described with reference to
the accompanying drawings in which:-
Figure 1 shows an elevational front side view of amounting device for a belt scraper (also in partial phantom)
in accordance with the invention;
Figure 2 shows a top plan view of the scraper
mounting (also in partial phantom) shown in Figure 1;
Figure 3 shows an elevational rear side view of
the mounting shown in Figure 1;
Figure 4 shows a perspective view of the mounting
device shown in Figure 1 fitted in an operating position
below a belt scraper;
Figure 5 shows an elevational side view of the
mounting device and cooperating scrapers of Figure 4;
Figure 6 shows on an enlarged scale the
scraper of Figures 4 and 5 during striking of an obstruction
on the running belt against the scraper blade; and
Eigure 7 shows an alternative belt scraper
configuration in which the scraper blade trails the scraper
mounting.
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DETAILED DESCRIPTION OF THE INVENTION
Referring to Figures l, 2 and 3 of the drawings,
numeral 10 generally indicates the blade mounting device.
It is of a composite construction oomprising a lever arm 12,
which has at its one free end an annular ring-like formation
14 defining an aperture 16. At its other end, the lever arm
12 is mounted to pivot about a pivot axis 18.
The mounting 10 further includes a biasing means
i.n the form of a torque - generating means 20 located at the
pivot a~is 18 and which comprises a tubular sleeve 22
conveniently of square cross-section. It further includes a
solid shaft 24 preferably of square cross section (Fig. 3)
mounted inside the sleeve 22 by means of four pads 26,
chosen of an elastic material, such as natural or synthetic
rubber, which are interposed between the sleeve 2~ and the
shaft 24. When the shaft 24 is turned, the pads ~6 are
compressed, and thereby torque is qenerated which resists
the rotation of the shaft 24 and tends to return it to a
neutral position.
The mounting 10 further includes a vertical sleeve
28 having a substantial axial bore 30 The sleeve 22 of the
torque generating means 20 is secured abutting to the sleeve
28 by means of an attachment 32, for example, in the form of
welding, with or without a gusset. The angular disposition
of the lever arm 12 is adjustable by means of a basing screw
34 which can be screwed into or out of a fixed position nut
36 held fast with the sleeve 28. A lock nut 37 secures the
screw 34 once placed in a desired position.
Referring further to Figure 1, the arm 12 is shown
in dotted lines in its neutral position. It can be
displaced through an angle 38 from its ~eutral position, and
this angle is about 55. In order to pre-stress the torque,
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generating means 20, the lever arm 12 is displaced ~!rom
its neutral position through an angle 40 which may be about
25, and the screw 34 is screwed to the desired position and
locked by the lock nut 37. This serves to retain the lever
arm in this position to ensure that the belt scraper
assembly tracks the belt. It also permits the scraper
assembly to be arcuately displaced via the lever arm 12 when
an obstruction projecting from the belt strikes against the
scraper assembly. When the mounting lO is thusly pre-
stressed, it is ready for installation in its operating
position as is shown in Fi~ures 4 and 5.
Referring now to Figures 4 and 5, the mounting
device lO is shown installed in its operating position on a
belt scraper assembly generally 42, so that the assembly is
biased to track and scrape a belt 44. The assembly 42
includes a carrier in the form of a scraper mounting shaft
46, and a plurality of scraping ~lades 48 mounted via a
pivotal link 50 and a line 51 on the shaft 46. The shaft 46
extends through the annular formation 14 (Fig. l) of the
lever arm 12 of the mounting device 10. The annular
formation 14 is clamped to the shaft 46 by means of clamping
screws 52. The mounting lO is fitted in its operating
position by means of a screw-threaded, vertical shaft 54
(fig. 4) which extends through the bore 30 of the sleeve 28.
The sleeve ~8 is secured in an axial position on the shaft
54 by means of upper and lower locknuts 56 and 58. The
shaft 54 is secured at its topmost end to a frame assembly
60 which is parallel to the upper run of the conveyor belt.
During normal operation, the belt drum 62 rotates
in the direction of arrow 64 and the belt 44 is driven in
the direction of arrow 66. The scraper assembly 42 is
biased against the lower belt 44 by means of the pre-set
torque provided in the torque generating means 20 of the
mounting 10, and also by means of torgue generated in
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elastic pads 45 provided around a scraper unit pivotal solid
shaft 43, which functions similar to the torque generating
means 20 on device 10. By referring to Figure 5, it will be
seen that the scraper assembly 42 can thus be arcuately
displaced along an arcuate path 68 about the pivotal axis 18
of the lever arm 12, the radius of the arcuate path 68 being
indicated by reference numeral 70.
Referring further to Figure 5 (and also to Figure
6,) when an obstruction 72 projecting from the under running
belt 44 strikes against the scraper blade 48, the blade is
forced away from the belt to the position 48.1 shown in
phantom view. It does so by displacing the bar link 51 to
the position 51.1 shown in phantom, and the lever arm 12 to
the position 12.1 shown in phantom, around the pivot axis
18, against the preset torque - generated in the torque
generating means 20. Thereby, the scraper blade 48 can
clear the moving obstruction 7~ without any damage to the
blade, whereafter the blade is forced back against the
running belt 44, because of means 20.
Referring to Figure 7, there is shown an
alternative embodiment. A belt scraper 74 in which the
scraper blade 48 trails the pivot axis 18 device 10, instead
of leading it, as is shown in Figure 5. In this embodiment,
a vertical line 76 passes through the extreme face 78 of
the scraper blade 48, closest to or in contact with the belt
44, and also through the carrier shaft 46. It is at an
angle 80 to the surface of the belt 44, the angle 80 being
from 85 to 95, and preferably at 90.
