Sealing apron device for the loading trough of a belt conveyor

Sealing apron device for a moving conveyor belt or loading trough of a belt conveyor, has at least one mounting plate which is fitted above the belt and which has a vertically adjustable sealing apron on a side wall. The underside of the apron interacts with the belt for sealing, and the sealing apron comprises a number of adjacent sections which are vertically slidable relative to each other on the mounting plate by means of slide guides on the mounting plate and the apron sections respectively. Each apron section is so fixed to the mounting plate with a clamping plate or bracket and fixing members that an apron section is clamped between the clamping plate and the mounting plate. A friction element between the clamping plate and sealing apron sections permits a downward movement of the section relative to the mounting plate, but impede an upward movement thereof.

The invention relates to a sealing apron device or conveyor skirt board for 
a moving conveyor belt or loading trough of a belt conveyor, provided with 
at least one mounting plate which is to be fitted above the belt and which 
bears a sealing apron in a vertically adjustable manner on a side wall, 
the underside of which apron can interact with the belt for sealing, and 
which sealing apron is made of a number of adjacent sections which are 
vertically slidable relative to each other on the mounting plate by means 
of slide guide means on the mounting plate and the apron sections 
respectively. 
Such a sealing apron device is known from the British Patent Specification 
GB 2,208,838. 
The known sealing apron device has a sealing apron which is made up of a 
number of adjacent sections which are fixed so that they can slide in the 
vertical direction on a mounting plate. Each apron section is preferably 
slotted and individually bolted at a predetermined torque by bolt and nut 
assembly to the mounting plate. A disadvantage of this method of fixing is 
that the friction between a clamping plate and the corresponding skirt 
board section changes very sudden what makes it very difficult to fix each 
skirt board section with a predetermined torque to the mounting plate. Due 
to trembling the tension of the predetermined torque changes in time. 
Another disadvantage is that in order to be able to change the sections, 
they have to be moved in the vertical direction, i.e. upwards or downwards 
by means of a hammer. In the downward direction this causes the problem 
that the predetermined torque changes, while for the vertical movement of 
the apron sections in the upward direction the disadvantage is that the 
nut has to be loosened and then fixed to a predetermined torque. Removing 
the sections forwards, i.e. out of the vertical plane of the mounting 
plate, is very difficult, and for this three apron sections havae to be 
loosened, due to the fact that the sections are interconnected to each 
other by tongues. 
Such a sealing apron device is known from American Patent Specification 
U.S. Pat. No. 4,236,628. 
The known sealing apron device has a sealing apron which is made up of a 
number of adjacent sections which are fixed so that they can slide in the 
vertical direction on a mounting plate. Each apron section is preferably 
fixed by means of dovetail-type guides on the mounting plate. A 
disadvantage of this method of fixing is that, in order to be able to 
change the sections, they have to be moved in the vertical direction, i.e. 
upwards or downwards. In the downward direction this causes the problem 
that the conveyor belt is situated below the sections, while during the 
vertical movement of the apron sections in the upward direction the 
disadvantage is that a toothing is present which is for the very purpose 
of preventing the sections from being able to move upwards in the vertical 
direction. Removing the sections forwards, i.e. out of the vertical plane 
of the mounting plate, is very difficult, and for this an apron section 
has to be more or less broken out, which means that the apron section in 
question is more or less destroyed and the chance of damage to the 
remaining apron sections is very great. Another disadvantage is that, if 
the separate sealing apron sections are adjusted too far downwards, great 
wear occurs because the pressure of the apron sections on the conveyor 
belt becomes too great, because the sections cannot be set back up again 
since the toothing present prevents this. The only way of correcting this 
faulty setting is to break out the apron sections in the same way as 
during their replacement and to insert them into their guides again from 
the top. The chance of damaging the apron section in question and/or the 
sections lying next to them is very great here. 
The object of the invention is a sealing apron device in which a number of 
apron sections are fixed on a mounting plate, and in which each apron 
section can be changed in a simple way independently of the other apron 
sections and if the adjustment is too deep, the faulty setting can easily 
be corrected. 
This object of the invention is achieved with a device through the fact 
that each apron section can be fixed in such a way to the mounting plate 
with the aid of a clamping plate or bracket and fixing means that an apron 
section is clamped between the clamping plate and the mounting plate. The 
advantage of such a method of composing a sealing apron device is that the 
clamping plate can be removed in a simple manner, following which the 
apron section can be removed very easily between the other apron sections. 
A new apron section can then be fixed in a simple manner on the vacant 
position, and the new apron section is then fixed tightly on the mounting 
plate with the aid of the same clamping means. 
In a preferred embodiment of the sealing apron device according to the 
invention, friction means are fitted between the clamping plate and the 
sealing apron sections, which friction means permit a downward movement of 
the section on the mounting plate, but impede an upward movement thereof. 
These measures ensure that the apron sections cannot make an upward 
movement, which would cause the seal of the sealing apron device to be 
inadequate. 
The clamping plate of the sealing apron device according to the invention 
is preferably U-shaped in cross-section with legs which extend downward on 
either side in the direction at right angles to the cross-section and can 
be accommodated in grooves on either side of the longitudinal hole in each 
apron section, and the two legs of the U-shaped plate and/or the grooves 
in an apron section are provided with friction means. It has been found 
that such a clamping plate holds the apron section very well in a tight 
fit in the correct position, which prevents the apron sections from being 
able to turn and any cracks from being able to occur between the different 
apron sections. Such a U-shaped clamping plate can also be provided very 
simply with friction means consisting of teeth which are directed in such 
a way that they permit only a downward movement of the section relative to 
the mounting plate. Such preferred embodiments make it possible to release 
a clamping plate fully or partially by undoing the fixing means, with the 
result that the sealing apron section clamped under it is then also 
adjustable in the upward direction, because the pressure of the friction 
elements is removed through the release. This is very useful if, for 
example, an apron section has been moved too far down, so that too great 
pressure is being exerted on the conveyor belt. 
Making each apron section of the sealing apron device preferably 
symmetrical both in the longitudinal direction and in the transverse 
direction means that when one end of such an apron section is worn out it 
can be turned over and the other end can be used. An apron section is 
consequently used more efficiently, for the centre part, which is no 
longer of any use after the apron section is worn out, now lasts twice as 
long. 
In another preferred embodiment of the device, the mounting plate is 
flanged in the lengthwise direction near the underside, and each apron 
section is provided with a recess near the underside, so that it can 
interact with the raised edge of the mounting plate. Such an edge not only 
strengthens the mounting plate, but also prevents the apron sections from 
being worn more than is efficient, otherwise the sealing of the apron 
sections will no longer be adequate. This flanged edge also prevents the 
accumulation of material between the apron sections and the mounting 
plate. 
The distance between the U-shaped legs of the clamping plate is preferably 
at least half the width of an apron section, which means that the 
different apron sections can be fixed well so that they are flat and 
sturdy. In a preferred embodiment the mounting plate can, if desired, be 
provided with several guide strips which can interact with several 
recesses in an apron section, which means that each apron section can be 
moved only in the vertical direction, and twisting of an apron section can 
no longer occur at all.

FIG. 1 shows a belt conveyor 1 with a moving conveyor belt or loading 
trough 2 on which the materials 3 to be conveyed are deposited through a 
chute 4, and are conveyed from there, the conveyor belt 2 being supported 
by a number of rollers 5. A U-shaped sealing apron device 6 according to 
the invention is fitted near the position where the chute 4 deposits the 
materials 3 on the moving belt 2. The sealing apron device 6 comprises a 
mounting plate 7 consisting of a rigid flat metal plate of which the 
underside is flanged, thereby forming a flange 8. The device shown in FIG. 
1 comprises a mounting plate 7 which is in this case welded to the plates 
9 forming the end of the chute 4. 
FIG. 2 shows another embodiment of the mounting plate 7 together with a 
vertically movable apron section 10 of the sealing apron device. In this 
case the mounting plate 7 is flanged both at the underside, producing a 
flange 8 at the underside, and at the top, forming a flange 11. A number 
of guide strips 12 are fitted, for example welded, at equal intervals on 
the mounting plate 7, on which strips a spacer 13 provided with a threaded 
hole 14 is fitted. With the aid of a U-shaped clamping bracket 15, a 
sealing apron section 10 can be fixed in the correct position on the 
mounting plate 7 by means of a bolt 16. The distance between the guide 
strips 12 with spacer 13 corresponds exactly to the width of a sealing 
apron section 10. 
FIG. 3 shows the various parts before they are fixed on the mounting plate. 
The sealing apron section 10 is made of rubber, polyurethane or another 
soft material. The guide strips 12 are preferably made of steel, but they 
can also be made of other materials, for example of a smooth plastic, in 
order to obtain a lower friction. When steel guide strips are used, they 
are preferably welded onto the mounting plate, and when plastic or other 
materials are used, screws or pop rivets can, for example, be used for the 
fixing. The sealing apron sections 10 are provided with two grooves 17 
into which the legs 18 of the U-shaped clamping bracket 15 fit. The legs 
18 of the clamping bracket 15 are provided with one or more 2 sawteeth 19 
which are directed in one direction, with the result that the sealing 
apron section 10 can be hammered only downwards with a hammer, while the 
sawteeth 19 at the same time prevent an upward movement of the sealing 
apron section. The sealing apron sections 10 are also provided with an 
elongated aperture or longitudinal hole 20 through which said section can 
move over the spacer 13 in the vertical direction. At the rear side each 
sealing apron section is provided with a space 21 having on either side 
projecting parts 22, said space 21 being exactly the same width as the 
guide strips 12. The projecting parts 22 do not run entirely to the 
bottom, with the result that when the sealing apron sections are fixed on 
the mounting plate 7 they can be moved in the vertical direction only 
until the projecting parts 22 come against the flanged edge 8 of the 
mounting plate 7. The movement distance of each sealing apron section is 
also determined by the elongated aperture 20. 
FIGS. 4, 5 and 6 show another example of an embodiment of a sealing apron 
section 10, which in this case comprises a sealing apron section which is 
symmetrical both in the lengthwise direction and in the transverse 
direction, which means that both sides of the sealing apron sections can 
be used.