Filling arrangement for a bulk unloader

The invention concerns a filling arrangement (12) for a bulk unloader having a conveyor belt travelling in an endless path and provided with material receiving pockets (9). The arrangement is characterised by a filler wheel (31) having an essentially horizontal main axis (A) and comprising: two runners (80) which are rotatable about the main axis (A) and against which lateral belt portions (23) of the conveyor belt (10) abut, wherein said pockets (9) are travelling between the runners (80) and are open towards the interior of the filler wheel (31) for receiving material being supplied essentially axially via an inlet opening (39) through a first one of said runners (80), and a tubular wall in the shape of a frusto-conical member (70), which has a symmetry axis extending essentially in parallel with said main axis (A) and which is arranged to rotate about said symmetry axis, said frusto-conical member (70) diverging from the inlet opening (39) towards the pockets (9) disposed between the runners (80), in order to guide the material into said pockets.

The present invention relates to a filling arrangement for a bulk unloader 
having a conveyor belt travelling in an endless path and provided with 
material receiving pockets. 
Unloaders of the kind referred to above are described for instance in SE 
9201558-5, SE 9202034-6 and SE 9302695-3. In SE 9202034-6 is described a 
ship unloader comprising a vertically movable horizontal arm and a 
vertical arm, the latter being supported at the outer end of the 
horizontal arm for pendulum movements, said conveyor belt travelling in an 
endless path along the horizontal and vertical arms. The conveyor belt 
travels around a turning wheel disposed at a lower end of the vertical 
arm, and adjacent said turning wheel is arranged a screw conveyor 
receiving bulk material from the ship hull at its lower end and having a 
peripheral side opening at its upper end, formed in the screw housing, for 
transferring (of) the material to the conveyor belt pockets. This 
prior-art unloader, as well as the unloaders described in the other two 
documents referred to above, is characterised in that the open sides of 
the pockets are turned away from one another, i.e. the bulk material is 
loaded and unloaded on the outwardly facing side of the belt. For this 
reason the material-carrying transportation part of the belt must run 
above the return part in the horizontal arm, and consequently the return 
part pockets open downwards in the horizontal arm. A disadvantage inherent 
in this arrangement is that any remaining material that may be present in 
the incompletely emptied pockets in the belt return part will be shaken 
loose from said pockets as the latter are travelling along the horizontal 
arm, and thus fall down from the unloader. Considering the comparatively 
high capacity of such unloaders considerable quantities of the material 
may fall down from incompletely emptied pockets. 
The subject invention has for its purpose to remedy this disadvantage found 
in the prior-art technology. 
In accordance with the invention a filling arrangement for a bulk unloader 
thus is provided by means of which it becomes possible to turn the 
conveyor belt pockets towards each other and yet achieve efficient filling 
of the material into the belt pockets. Thus, it becomes possible to 
arrange for the transportation part of the belt to travel below the return 
part inside the horizontal arm, with the result that the return part 
pocket will open downwards, towards the upwardly open pockets of the 
transportation part. The advantage of this arrangement is that any 
material that may fall out of any incompletely emptied pockets in the 
return part will be guided into the pockets below in the transportation 
part and be carried by said part to the intended belt discharge station. 
In this manner, undesired emptying of material from the unloader is 
avoided. 
More precisely, the subject invention provides an arrangement whereby it 
becomes possible to fill inwardly-facing pockets of the kind indicated, in 
a safe and efficient manner. 
The arrangement in accordance with the invention is characterised in that 
it comprises a filler wheel having an essentially horizontal main axis and 
arranged to be used specifically but not exclusively as a turning wheel at 
the lower end of a vertical arm in an unloader of the kind defined above. 
However, the filler wheel is generally useful also in other applications 
than in connection with the type of ship unloader described above. 
In accordance with the invention, the filler wheel comprises two runners, 
which are rotatable about the main axis and against which belt edge 
portions of the conveyor belt abut, said pockets travelling between the 
runners with the pockets opening towards the interior of the filler wheel 
for receiving material supplied essentially axially via an inlet opening 
through a first one of said runners. In order to prevent the material 
supplied into the inlet opening from causing undesired clogging of the 
filler wheel and/or build-up of layers of material therein, and also to 
ensure that the material supplied is safely transferred into the pockets, 
the filler wheel comprises a tubular wall shaped as a frusto-conical 
member having a symmetry axis extending essentially in parallel with the 
main axis and being arranged to rotate about said symmetry axis. The 
frusto-conical member diverges in the direction from the inlet opening 
towards the pockets disposed between the runners, in order to guide the 
material into said pockets. By providing a rotating frusto-conical member 
of this kind any problems that might arise because of insufficient angles 
of repose will be eliminated, as will appear from the subsequent 
description of embodiments of the invention. 
The main axis of the filler wheel about which the runners rotate, and the 
cone symmetry axis about which the frusto-conical member rotates, 
preferably coincide but could also be displaced with respect to one 
another. The above expression "essentially in parallel with" is intended 
to encompass both the case in which the axes are entirely parallel and the 
case in which the axes extend somewhat obliquely relatively to one 
another, however only up to a degree ensuring that the intended effect of 
the conical member is achieved. 
It is possible to provide a separate drive means for the rotating 
frusto-conical member but the latter could also be connected to at least 
one of the runners in order to be caused to rotate. In accordance with one 
embodiment the frusto-conical member is rigidly connected to one of the 
runners in order to corotate therewith. 
Preferably, the filler wheel has two frusto-conical members of the above 
kind, both of which are adapted to rotate about the main axis and arranged 
with their bases or larger ends facing one another and spaced axially 
apart, whereby the bulk material supplied through the inlet opening is 
guided down into the pockets by way of a gap formed between the conical 
members. In accordance with this embodiment, the conical members may be 
connected to a respective one of the runners at their small ends in order 
to be caused to rotate. 
For mounting purposes, the filler wheel may comprise a tubular housing 
disposed about the main axis and having two end walls and an intermediate 
peripheral wall connected thereto. The inlet opening will then be provided 
in one of the end walls. The runners are rotatably mounted on a respective 
one of the end walls, and at its lower part the peripheral wall is 
provided with a outlet opening through which the material may pass from 
the conical member or members, down into the pockets. 
Preferably, the filling arrangement in accordance with the invention also 
comprises a screw conveyor arranged for pendulum movements about the main 
axis of the filler wheel, said screw conveyor having a outlet opening at 
its upper end which opens into the inlet opening of the filler wheel and 
having a feed-in device at its lower end for feeding of material into the 
screw conveyor. 
In accordance with a preferred embodiment of the invention the 
frusto-conical member, or members if two are provided, is/are adapted to 
rotate about its/their symmetry axis in a direction opposite to the 
rotational direction of the runners. An advantage obtained by the use of 
counter-rotating frusto-conical members is that the material filling 
operation may take place essentially at the return part of the conveyor 
belt moving into the filler wheel instead of at the exiting transportation 
part of the conveyor belt. In this manner, undesired spilover material 
from the exiting transportation part can be prevented, as will be clearly 
apparent from the subsequent description of embodiments of the invention. 
EP-B1-0 284 154 illustrates extremely schematically (FIG. 9) a filling 
arrangement including double pendulum-movement screw conveyors, the 
discharge ends of which are facing one another towards a "cell belt" the 
pockets of which are said to face one another. However, this document 
provides no information regarding the function or construction of the 
arrangement in the area where the belt turns. More particularly, neither 
rotating runners nor rotating frusto-conical members of the kind described 
above are described or shown, and generally speaking the document does not 
disclose whether a filler wheel or similar device is provided. 
The features of the above and other embodiments of the invention are 
defined in the appended claims.

FIG. 1, to which reference is initially made, schematically illustrates a 
ship unloader 1 for unloading bulk material, such as coal, e.g. from a 
ship hull (not shown). The unloader 1 comprises a travelling bridge crane 
2, a tower 3, a horizontal arm 4 arranged to be vertically raised and 
lowered, a vertical arm 6 suspended from the outer end 5 of the horizontal 
arm, drive means 7 being arranged to actuate the vertical arm 6 for 
pendulum movements about a pendulum axis 8. Furthermore, the unloader 1 
comprises a conveyor belt provided with material-receiving pockets 9 (see 
FIG. 3), said belt designated generally by reference numeral 10 and 
travelling in an endless path along the horizontal arm 4 as well as the 
vertical arm 6, and also an emptying device, not described in closer 
detail herein, adjacent the tower 3. At the lower end of the vertical arm 
6, a filling arrangement 12 in accordance with the invention is provided 
for filling material into the pockets 9 of the belt 10. For a more 
detailed description of the emptying device at the tower 3 reference is 
made to Applicant's Swedish patent application SE 9502337-0, entitled 
"Emptying Arrangement for a Bulk Unloader", the disclosure of which is 
hereby incorporated by reference. 
As indicated by arrows in FIG. 1, the transportation part 13 of the belt 10 
travels along a lower path in the horizontal arm 4 whereas the return part 
14 thereof travels at the top of the horizontal arm 4. This is illustrated 
in greater detail in FIG. 2 wherein the framework forming the horizontal 
arm 4 is indicated by reference numerals 15-19. A housing comprising sides 
walls 20 and 21 and an upper wall 22 encloses and is connected with the 
frame work 15-19. In the interior of the horizontal arm 4, lateral belt 
portions 23 of the conveyor belt 10 rest on free-running belt rollers 24 
with the downwards open pockets 9 of the return belt part 14 being 
positioned straight above the upwardly open pockets 9 of the 
transportation belt part 13. Oblique lateral protective members 28 extend 
along the length of the horizontal arm 4, forming a channel for guiding 
any material that might fall down from incompletely emptied pockets 9 of 
the return part 14. 
FIGS. 2 and 3 in combination illustrate the structure of the belt 10 to be 
used in the unloader 1 in FIG. 1. As already mentioned, the conveyor belt 
10 comprises two lateral belt portions, one of which is illustrated in 
FIG. 3. Intermediate said lateral belt portions 23 extend triangular 
interconnection beams 26 to which the ends of the essentially U-shaped 
pockets 9 are connected. The sides of the pockets 9 are closed by side 
walls (not shown). A belt of this kind is marketed by Trelex Flexowell 
GmbH, Germany. Reference numeral 27 designates the open side of the 
pockets 9 and 28 designates a bottom trough extending in the longitudinal 
direction of the horizontal arm 4 to collect any material falling down. 
A first embodiment of the filling arrangement 12 in FIG. 1 will be 
described in detail with reference to FIGS. 4-11. Reference is initially 
made to FIGS. 4A and 4B and to FIG. 5. It should be noted that for the 
sake of clarity the pockets 9 are not shown in the lateral view in FIG. 
4B. The stand of the vertical arm 6 supports, at its lower end, a filler 
wheel 31 by means of flange connection 30. The filler wheel 31 serves as a 
turning wheel for the conveyor belt 10 at the lower end of the vertical 
arm 6, the open side 27 of the pockets 9 being turned inwards, towards the 
filler wheel 31, as appears from FIGS. 4A and 5. 
At one end wall of the filler wheel 31 a screw conveyor of a kind known per 
se, generally designated by 32, is provided, comprising a feed screw (not 
shown) driven by a motor 33, and a housing 34 enclosing the feed screw. At 
the lower end of the screw conveyor 32 a feed-in device 35, not described 
in any greater detail, is provided to feed bulk material into the screw 
conveyor 32. At its upper end, the screw housing 34 is formed with a 
peripheral outlet opening which is connected to the end wall of the filler 
wheel 31 by means of a short conduit 36. 
The screw conveyor 32 is suspended in the stand of the vertical arm 6 by 
means of a support member 37 and arranged for pendulum movements about a 
main axis A of the filler wheel 31. The pendulum movement, which is 
indicated by double arrows in FIG. 4B and which is accomplished by means 
of a turning device 38, allows the feed-in device 35 to be set in an 
essentially perpendicular position relatively to the hull bottom, 
independently of the pendulum position of the vertical arm 6 relative to 
the vertical. 
As most clearly apparent from FIG. 5 which illustrates the arrangement in 
FIG. 4A on an enlarged scale, an annular gap 4 exists between the outlet 
conduit 36 of the screw conveyor 32 and a material inlet opening in the 
end wall of the filler wheel 31. To this end, the conduit 36 is rotatably 
mounted in a bearing in a second support member 42 projecting downwards 
from the stand of the vertical arm 6. 
The filler wheel 31 will now be described in greater detail, reference 
being firs t made to FIGS. 8-11 illustrating the components of the wheel 
31 in an unassembled condition. 
The filler wheel 31 comprises a tubular housing 50, two wheel holders 60, 
two truncated cones 70 and two runners 80. 
The tubular housing 50 is formed by a cylindrical peripheral wall 51 and 
two end walls 52a, 52b in the form of annular tubular beams, and a beam 
connection means 53 upstanding from the upper side of the peripheral wall 
51 and including an connection flange 54 to produce the flange connection 
30 illustrated in FIGS. 4A and 5. At its bottom, the peripheral wall 51 is 
provided with a circumferentially extending material outlet opening 55 
which, as illustrated in FIG. 8B, extends upwardly on both sides of the 
peripheral wall 51. However, the outlet opening 55 extends to a somewhat 
higher level on the ascending side of the belt as indicated at 56, i.e. on 
the side on which the filled pockets 9 travel. The reason for this 
arrangement is to ensure that any projecting material will be allowed to 
drop back into the filler wheel 31 for reintroduction into another pocket 
9. The end 57 opposite to the outlet opening 55 determines when the 
filling of the pockets may start as the latter are traveling around the 
filler wheel 31. The configuration of the outlet opening 55 may, however, 
be different in accordance with the embodiment of the invention to be 
described below and comprising counter-rotating frusto-conical members. 
In addition, the housing 50 is provided with a protective flange 58a, 58b 
on each one of the end walls 52a, 52b and as will appear from the 
following, said flanges serve to prevent material from reaching wheel 
races in the filler wheel 31. 
Finally, the two end walls 52a, 52b are also provided with bolt apertures 
59 for establishing a bolt connection with an associated wheel holder 60, 
as will be described with reference to FIGS. 9A and 9B. 
A wheel holder 60 comprises a circular ring or flange 61 having essentially 
the same diameter as the end walls 52a, 52b of the housing 50 and 
presenting bolt apertures 62 matching the bolt holes 59 of the housing 50. 
Further, the wheel holder 60 has three symmetrically disposed and freely 
rotatable flanged wheels 63 the peripheries of which project somewhat 
beyond the flanged ring 61 and which are provided with circumferential 
grooves 64. The flanged wheels 63 are rotatably mounted on the flange 61 
with the aid of angle irons 65 and oblique profile sections 66. 
Each cone 70 of the filler wheel 31, one of which is illustrated in FIG. 
10, consists of a tubular wall 71 in the form of a cylindrical 
frusto-conical member the small end 72 of which has a radially projecting 
annular connection flange 73 including a rigidifying element 74 which is 
turned towards the external face of the conical member 71. The height of 
the conical member 71 is so adapted to the axial length of the housing 50 
that in its assembled condition the filler wheel 31 (FIG. 6) presents a 
gap 75 between the bases 76 of the conical members 70. In addition, the 
diameter of the bases 76 of the conical members 70 is slightly smaller 
than the internal diameter of the end walls 52a, 52b and the peripheral 
wall 51 of the tubular housing 50. 
The two runners 80 of the filler wheel 31, one of which is illustrated in 
FIGS. 11A and 11B, on the one hand as an essentially T-shaped transverse 
section formed from a radial rail ring 81 for engagement with the 
circumferential groove 64 of the flanged wheel 63, and also a circular 
outer portion 82 forming the race on which the belt portions 23 run. The 
diameter of the runner 80 is so adapted to the flanged wheels 63 that the 
runner, in a manner similar to the outer race of a roller bearing, runs on 
said flanged wheels 63. In addition, each runner 80 has four triangular 
cone supporting plates 83 which are secured to the outer portion 82 of the 
runner 80 at one of their ends, whereas their radially inwardly directed 
corners are arranged to be connected to a conical member 70 via the 
connection flange 73. The structure including the separate plates 83 is 
advantageous compared to the alternative of using one continuous annular 
plate inasmuch as material that may enter into the wheel holder may be 
efficiently guided outwards through the gaps between the plates 83. 
Reference is now made to FIGS. 6 and 7 illustrating the assembled filler 
wheel 31, seen in a sectional view from the front and in an end view from 
one end wall, respectively. In accordance with its basic embodiment 
illustrated in FIG. 6 the filler wheel 31 has one inlet opening 39 in each 
end wall 52a, 52b. However, in the embodiment in FIGS. 1, 4A, 4B and 5 one 
inlet opening is closed by a plate (not shown) which is mounted at 
reference numeral 44 in FIGS. 4A and 5. These inlet openings 39 thus 
coincide with the small ends 72 of the conical members 70 the facing bases 
76 of which are spaced apart by a distance 75 as mentioned above, whereby 
material supplied through one or both inlet openings 39 may be guided by 
the conical members 70 down into the outlet opening 55 of the housing 50 
and further down into the upwardly open pockets 9 (not shown in FIG. 6). 
For this purpose oblique sealing strips 41 are also provided, which are 
mounted on a respective one of the end walls 52a, 52b, at least at a lower 
part of the outlet opening 55. 
FIGS. 6 and 7 illustrate the manner in which the interconnection flanges 61 
of the wheel holders 60 by means of bolt joints 42 are secured to the end 
walls 52a, 52b of the housing 50, using the holes 59. In addition, these 
Figures illustrate the manner in which the conical members 70 are 
supported by one runner 80 each, with the aid of the star-shaped 
arrangement of the cone supporting plates 83 and the cone connection 
flanges 73 and the bolt joint 43. Owing to this arrangement each conical 
member 70 will rotate together with its associated runner 80. 
FIG. 6 also illustrates the manner in which the protective flanges 58a and 
58b efficiently protect the flanged wheels 63 and the rail rings 81 from 
any dropping material. 
The fact that the conical members 70 rotate inside the filler wheel 31 
ensures that the material supplied by the screw conveyor 32 through the 
inlet opening 39 is satisfactorily guided into the pockets 9. More 
precisely, no problems concerning the angles of repose will arise, since 
material that for any reason does not fall into the pockets by itself will 
be entrained by the rotating conical members 70 and therefore leave the 
latter at least when it reaches the upper part of the filler wheel 31. The 
arrangement makes it possible to provide stationary, interior scraper 
devices (not shown) inside each conical member. 
The primary reason for providing the filler wheel 31 with two conical 
members is the fact that material discharged from the screw conveyor 32 
may enter the filler wheel 31 at different velocities. Low-velocity 
material, which could be said to more or less gush into the filler wheel, 
will be guided by the left-hand conical member 70 as seen in FIG. 4A 
whereas higher-velocity material, which will more or less be thrown into 
the filler wheel 31, will be guided by the right-hand conical member 70 as 
seen in FIG. 4A. 
Reference is now made to FIG. 12 illustrating a second embodiment of the 
filling arrangement 12 according to which both inlet openings 39 are used 
and, to this end, the vertical arm 6 supports two screw conveyors 32a, 32b 
arranged for pendulum movement, each one equipped with its 
pendulum-imparting cylinder 38a, 38b. In this manner it becomes possible 
specifically to pendulate the screw conveyors 32a, 32b in different 
directions to accomplish an efficient unloading. 
FIG. 13 is a schematic representation of the manner in which the material 
is filled onto the conveyor belt 10 by means of the above-described 
embodiments of the filling arrangement in accordance with the invention. 
As a result of the conical members 70 corotating with the runners 80 the 
material present on the conical members 70 will be entrained thereby in 
their rotational direction, i.e. counter-clockwise as seen in FIG. 13, in 
the direction of the movement of the ascending transportation part of the 
conveyor belt 10. The material, indicated by G in FIG. 13, thus will be 
filled into the pockets 9 approximately in the manner illustrated in that 
Figure. Due to the construction of the belt 10 (see FIG. 3) small 
"shelves" 100 will, however, form in the ascending transportation part, on 
top of the triangular interconnection beams 26 of the belt 10. Because the 
material G places itself on top of these shelves 100 it may drop from the 
ascending transportation part of the belt 10 as unwanted spilover 
material. However, this disadvantage may be eliminated, or at least be 
essentially reduced, if the conical member(s) and the conveyor belt 10 are 
caused to rotate in opposite directions. 
If the conical members 70 are caused to rotate in the opposite direction to 
that of the runners 80 the material present on the conical members 70 will 
be entrained thereby obliquely upwards towards the incoming return part of 
the belt 10, i.e. clockwise as seen in FIG. 14. Consequently, in 
accordance with FIG. 14 the filling of material into the pockets will be 
effected essentially in the descending part of the belt 10, where the 
"shelves" 100 referred to above do not exist. The above-mentioned problems 
with spilover material thus is avoided. In this connection it should also 
be noted that the filling of the pockets essentially will become 
independent of the actual pendulum angle of the vertical arm 6 of the 
unloader, i.e. the material will be deposited in each individual pocket 9 
as the latter assumes the correct position relatively to the vertical. 
FIGS. 15 and 16 illustrate a filler wheel including counter-rotating 
frusto-conical members in accordance with a third embodiment of the 
filling arrangement of the invention. Components that are identical with 
or correspond to the components of the filler wheel in accordance with 
FIGS. 4-11 have, for the sake of simplicity, the same reference numerals 
and the description of their function will not be repeated. 
The filler wheel in accordance with FIGS. 15 and 16 is characterised in 
that the cone supporting plates 83 have been omitted, and in that the 
counter-rotating conical members 70 instead are driven by the runners 80 
via the flanged wheels 63. More precisely, the annular connection flange 
73 of each conical member 70 is connected to the radially inner portion of 
an annular external plate 101 by means of bolt joints. At its radially 
outer part the external plate 101 is connected to an interior ring 103 via 
an intermediate ring 102 by means of bolt joints. The interior ring 103, 
which thus is rigidly connected to its associated conical member 70, has 
such a width and external radius that it fits into the flanged wheels 63 
so as to be driven thereby. In practise, only the two lower flanged wheels 
63 will be driving wheels whereas the upper flanged wheel 63 will serve 
merely as a lateral guide. 
In accordance with one embodiment the inner ring 103 is divided to 
facilitate its mounting onto the flanged wheel 63. For instance, it may be 
divided into three parts, extending through 90.degree., 90.degree., and 
180.degree., respectively. By using an unbroken intermediate ring 102 the 
parts of the inner ring 103 may be joined together by means of the 
above-mentioned bolt joints to form a continuous inner ring 103. However, 
it is equally possible to use an unbroken inner ring 103, which may 
however require a different sequence of the component assembly steps. 
FIGS. 17 and 18 illustrate a filler wheel comprising counter-rotating 
frusto-conical members in accordance with a fourth embodiment of the 
filling arrangement of the invention. The filler wheel in FIGS. 17 and 18 
is provided with a separate drive means for the counter-rotating conical 
members 70. For this purpose one inner ring 104 for each conical member 70 
is rigidly connected to the flange 61 of the wheel holder 60, which 
flange, via a bearing 105, runs on an outer ring 106. The outer ring 106 
is in turn rigidly connected to the connecting flange 73 of the conical 
member 70 via an annular plate 107 and bolt joints. In this manner, the 
conical member 70 becomes freely rotatable relatively to the wheel holder 
60, without any driving contact with the flanged wheels 63. A suitable 
motor 108 is provided to drive the conical members 70, as illustrated 
schematically in FIG. 17. The output shaft of the motor 108 is via a chain 
109 connected to a gear 110 rigidly mounted on a drive shaft 111 rotatably 
mounted in a bearing cage 112. In turn, the drive shaft 111 drives two 
gears 113, one at either end of the shaft 111, while said gears in turn 
via a chain 114 drive a respective one of the above-mentioned outer rings 
106, the latter for this purpose being formed with teeth on their external 
faces. 
Obviously, the above separate-drive arrangement could be used also in the 
case of corotating cones. 
FIG. 19 illustrates a modification of the filler wheel in FIGS. 15 and 16. 
During the assembly of the unloader the uppermost flanged wheel 63 in FIG. 
16 is initially supporting, i.e. it supports the weight of the runners 80 
and of the conical members 70. However, after mounting and tightening the 
belt 10 this weight will instead be taken by the belt 10, and the 
uppermost flanged wheel 63 will have a lateral guiding function only. 
Owing to this arrangement it becomes possible to choose a smaller 
diameter-sized upper flanged wheel, alternatively to move it upwards, into 
contact only radially outwards with the rail ring 81 of the runner 80. A . 
modification of this nature is illustrated in FIG. 19. In this case, the 
filler wheel may be supplemented by a second upper wheel 120, which abuts 
against and laterally guides the inner ring 103. As schematically 
illustrated in FIG. 19 this second wheel 120 is mounted on a pivotable 
bracket 121 which by means of a spring means 122 is positively urged 
against the inner ring 103 in order to ensure that correct abutment 
conditions exist between the wheel 120 and the inner ring 103, independent 
of any presence of dirt or other particles on the tread. As illustrated in 
FIG. 19 two additional wheels 120 of this kind may be provided, each 
having its own bracket 121 and its own spring means 122. 
Owing to the above modification including double wheels at the upper 
location, the radial positions of the two upper wheels 63 and 120 may be 
set individually, ensuring correct play. An obvious advantage with the 
provision of double wheels at the top is that the wheels will never will 
be stationary, which prevents jamming, as may otherwise occur, for 
instance because of corrosion. 
Another advantage with the embodiment including double upper wheels is that 
it facilitates assembly. The three flanged wheels 63 may be mounted 
initially in abutment against the rail ring 81. Thereafter, the inner 
rings 103 together with the conical members 70 are put in position 
relatively to the wheels 63, whereupon the second upper wheel 120 is 
mounted. 
The invention has now been described with reference to preferred 
embodiments but the filling arrangement in accordance with the invention 
may be modified in many ways within the scope of the appended claims. 
For instance, the arrangement may be used also in situations where no screw 
conveyor is used for the feed-in. In certain applications one of the 
frusto-conical members may be omitted. In addition, the conical members 
need not necessarily have a cylindrical shape. 
In accordance with one particularly interesting modification the cone 
symmetry axis is displaced relatively to the main axis A of the filler 
wheel in the direction towards the descending return part of the belt 10. 
This may be achieved by choosing a smaller diameter of the lower left-hand 
flanged wheel 63 in FIG. 16. Any dirt that may enter between the belt 10 
and the external face of the conical members 70 will be entrained by the 
belt 10 in the direction towards a space diverging in the direction of 
belt travel. This prevents dirt from being wedged by the belt 10. A very 
minor lateral displacement of the inner ring 103 may be sufficient to 
obtain this advantageous release effect.