Guide assembly for a curved section of a scraper-chain conveyor

A guide assembly for a curved section of a scraper-chain conveyor comprises a housing and two pulley wheels which are rotatably mounted within the housing. The pulley wheels constitute means for guiding the scrapers of a scraper assembly around the curved section. Each of the pulley wheels has an inner wheel part and a two-part scraper-engaging rim detachably connected to its inner wheel part.

BACKGROUND TO THE INVENTION 
This invention relates to a guide assembly for a curved section of a 
scraper-chain conveyor. 
In order to direct the scraper assembly of a scraper-chain conveyor around 
a curve in as friction-free a manner as possible, it is known to use a 
guide assembly having guide means constituted by two vertically-spaced, 
independently-rotatable pulley wheels. The scrapers of the scraper 
assembly bear radially against the upper pulley wheel when in the upper 
(conveying) run, and bear radially against the lower pulley wheel when in 
the lower (return) run. In operation, the pulley wheels are rotated by 
their interaction with the scrapers, and they conduct the scraper assembly 
around the curve with only low friction losses. Typically, an assembly of 
this type is used in an underground mine in the region where a longwall 
working joins a roadway, the assembly being used to guide the run of a 
longwall conveyor into the roadway. 
In this type of assembly, the vertical axle which carries the pulley wheels 
is held within a housing which accommodates the pulley wheels. The pulley 
wheels are circumferentially profiled to correspond to the profiling of 
the inner (scraper-guiding) side walls of the channel sections of the 
conveyor. 
In a known guide assembly of this type, the pulley wheels are rotatably 
mounted on their axle by means of roller bearings, and the pulley wheels, 
the axle and the bearings are removable as a unit from the guide assembly 
housing. This facilitates the fitting and dismantling of the heavy and 
bulky guide assembly to a curved conveyor section, and this is 
particularly important where space is restricted (as is normally the case 
at the longwall/roadway junctions of an undergound mine). A guide assembly 
of this type is described in DE-OS No. 2 817 949. 
The aim of the invention is to provide an improved guide assembly for a 
curved section of a scraper-chain conveyor. 
SUMMARY OF THE INVENTION 
The present invention provides a guide assembly for a curved section of a 
scraper-chain conveyor, the assembly comprising a housing and two pulley 
wheels which are rotatably mounted within the housing, the pulley wheels 
constituting means for guiding the scrapers of a scraper assembly around a 
curved section of a scraper-chain conveyor, wherein each of the pulley 
wheels has an inner wheel part and a multi-part scraper-engaging rim 
detachably connected to said inner wheel part. 
The separation of each pulley wheel into an inner wheel part and a 
multi-part hub enables the pulley wheels (which when fitted together are 
large and bulky) to be transported in bits. Moreover, the outer rims of 
the pulley wheels are easily replaceable, when worn, without the entire 
pulley wheels needing replacement. 
The inner wheel part of each pulley wheel may be of composite one-piece 
construction. This is advantageous from the point of view of stability, 
and it also helps with the mounting of the pulley wheels in the housing. 
Advantageously, the rim of each pulley wheel is constituted by two 
identical parts. Preferably, the rim of each of the pulley wheels is 
provided with a circumferential groove having a profile which matches the 
profile of the ends of the associated scrapers. 
In a preferred embodiment, the rim and inner wheel part of each pulley 
wheel are provided with overlapping flanges, and detachable connection 
means are provided for connecting said flanges to one another. 
Conveniently, the pulley wheels are independently rotatably mounted on an 
axle mounted within the housing. Preferably, the pulley wheels are 
rotatably mounted on a sleeve surrounding the axle by means of respective 
bearing assemblies, the pulley wheels, the bearing assemblies and the 
sleeve being removable from the housing as a unit, and the axle being 
removable from said sleeve. 
In a preferred embodiment, the housing is constituted by a base plate 
arranged beneath the pulley wheels, a cover plate arranged above the 
pulley wheels, and a panel arranged between the pulley wheels. 
Advantageously, the ends of the axle are supported by the base plate and 
the cover plate. 
The housing may be formed in two detachablyconnected parts. Preferably, the 
base plate, the cover plate and the panel are each formed in two parts, a 
common plane separating the two parts of the base plate, the cover plate 
and the panel, said plane of separation passing through the axis of the 
axle. Where the guide assembly is used with a curved conveyor section that 
curves through an arc of 90.degree., the plane of separation is preferably 
inclined at 45.degree. to each end of the curved conveyor section. 
Advantageously, the two parts of the base plate are detachably connected 
together, and the two parts of the cover plate are detachably connected 
together. Preferably, the adjoining edges of the two parts of the base 
plate are provided with downwardly-extending flanges which are detachably 
connected together, and wherein the two parts of the cover plate are 
provided with upwardly-extending flanges which are detachably connected 
together. Conveniently, said flanges are detachably connected together by 
means of joints and/or screw-threaded members. 
Preferably, the upper end of the axle is held within the cover plate by an 
upper end fitting, and the lower end of the axle is held within the base 
plate by a lower end fitting, and wherein each of said fittings is 
constituted by a pair of semi-cylindrical shells. 
The assembly may further comprise an annular connector ring which is 
detachably connected to the two parts of the base plate, the connector 
ring being seated in an annular groove formed in the base plate parts, the 
annular groove being coaxial with an axle. 
Advantageously, the circumferential groove in the rim of each pulley wheel 
has upper and lower inclined faces, said faces defining an included angle 
which is greater than the angle defined by the upper and lower faces of 
the ends of the associated scrapers. 
The invention also provides a curved section and guide assembly arrangement 
for a scraper-chain conveyor, the arrangement comprising a curved conveyor 
section and a guide assembly, the guide assembly being as defined above. 
Preferably, the base plate extends beneath the curved conveyor section, and 
the panel is joined to the floor plate of the curved conveyor section, and 
wherein said floor plate is formed in two parts whose plane of separation 
is the same as that of the panel. Conveniently, each part of the panel is 
connected to its associated floor plate part by means of a 
tongue-and-groove connection, and the two parts of the floor plate are 
detachably connected together. 
The invention further provides a guide assembly for a curved section of a 
scraper-chain conveyor, the assembly comprising a housing and two pulley 
wheels rotatably mounted in the housing, the housing being constituted by 
a base plate arranged beneath the pulley wheels, a cover plate arranged 
above the pulley wheels, and a panel arranged between the pulley wheels, 
wherein the base plate, the cover plate and the panel are each formed in 
two parts, a common plane separating the two parts of the base plate, the 
cover plate and the panel. 
Preferably, the pulley wheels are independently rotatably mounted on an 
axle, the ends of the axle being supported by the base plate and the cover 
plate, and wherein said plane of separation passes through the axis of the 
axle. This feature is advantageous in that the housing parts are separable 
for transportation purposes. Moreover, the pulley wheel units can be 
inserted into, and withdrawn from, the housing when the housing parts are 
unconnected. This facilitates the fitting and dismantling of the pulley 
wheels.

DESCRIPTION OF PREFERRED EMBODIMENT 
Referring to the drawings, FIG. 1 shows a curved conveyor section and guide 
assembly arrangement, indicated generally by the reference numeral 10, of 
a scraper-chain conveyor. The arrangement 10 includes a curved conveyor 
section 13 which serves to connect the end conveyor channel sections 11 
and 12 of two straight conveyor portions. Each of the straight conveyor 
portions is constituted, in a known manner, by a plurality of channel 
sections which are joined together end-to-end in such a manner as to 
permit limited articulation therebetween. The two straight conveyor 
portions lie at right-angles to one another, with the portion containing 
the channel section 11 being positioned in a longwall working (not shown), 
and with the portion containing the channel section 12 being positioned in 
a roadway (not shown). Thus, the curved section 13 curves through 
90.degree.. 
The arrangement 10 includes, in one constructional unit, the curved section 
13 and a housing 14 containing upper and lower pulley wheels 15 and 16 
respectively. The pulley wheels 15 and 16 are independently rotatably 
mounted on a common vertical axle 17 attached to the housing 14. The 
pulley wheels 15 and 16 engage the inner ends of the scrapers of the 
scraper assembly of the conveyor so as to guide the scraper assembly round 
the curved section 13. The housing 14 is of two-part construction, being 
divided into two parts 14A and 14B along the plane M of the section line 
II--II (see FIG. 1). The plane M of division thus lies at 45.degree. to 
each of the straight conveyor portions. The housing 14 is constituted by a 
two-part base plate 18, a two-part panel 19, and a two-part cover plate 
20. The panel 19 separates the pulley wheels 15 and 16, and is joined to 
the floor plate 19' of the curved section 13. The two parts of the base 
plate 18, the panel 19 and the cover plate 20 are firmly, but detachably, 
connected to one another along the plane M. Thus, vertical flanges 21 are 
welded to the adjoining edges of the two parts of the base plate 18, and 
these flanges are detachably connected together by joints 22 and bolts 23. 
Similarly, the two parts of the cover plate 20 are connected together by 
means of welded-on vertical flanges 21, joints 22 and bolts 23. 
The axle 17 is guided and supported in the housing 14 by means of an upper 
fitting 24 associated with the cover plate 20, and by means of a lower 
fitting 25 associated with the base plate 18. These fittings 24 and 25 
take up the forces acting on the pulley wheels 15 and 16. Each of the 
fittings 24 and 25 defines a bore for receiving a free end of the axle 17, 
and each is constituted by a pair of semi-cylindrical shells. Each of 
these shells forms part of, or is attached to, the associated part of the 
base plate 18 or the cover plate 20. 
At the outer portion of the curved section 13, the floor plate 19' is 
connected to the base plate 18 by means of vertical flanges 26. The 
flanges 26 extend upwards from the base plate 18 to the upper edge of the 
outer side wall 27 of the curved section 13. The two flanges 26 are 
detachably connected together by means of joints 22 and bolts 23, and so 
assist with the detachable connection of the two housing parts 14A and 
14B. A further connection between the two housing parts 14A and 14B can be 
effected, in the region of their flanges 26, by means of external 
reinforcement members 26' (see FIG. 1). The two parts of the panel 19 are 
connected to the two parts of the floor plate 19' by means of 
tongue-and-groove joints 53. An access aperture in the parts of the floor 
plate 19' of the curved section 13 is covered by an insert plate 28. This 
insert plate 28 is inset into the floor plate 19', and is screwed to the 
two parts thereof. Consequently, the insert plate 28 also helps to connect 
the two parts of the floor plate 19' and hence to connect the two parts of 
the panel 19. 
As shown in FIGS. 2 and 3, the two parts 14A and 14B of the housing 14 are 
also connected together by means of an annular connector 29. The connector 
29 is seated within an annular recess 30 formed in the underneath side of 
the two-part base plate 18, and is screwed to these base plate parts by 
means of bolts 31. The connector 29 serves to align the two housing parts 
14A and 14B in the region of the lower fitting 25. 
As shown in FIG. 1, each end of the curved section 13 is somewhat Z-shaped 
in plan. Thus, the end face 32 of the floor plate (panel) 19 extends at an 
acute angle to the conveying direction F, whereas the end faces 33 and 34 
of the side walls of the curved section 13 extend, in the usual way, at 
right-angles to the conveying direction. The end faces 33 and 34 are, 
however, off-set with respect to one another in the conveying direction F. 
The adjoining channel sections 11 and 12 of the straight conveyor portions 
are joined to the assembly 10 at these end faces 33 and 34. 
The two parts of the cover plate 20 are also connected together in the 
region of the upper fitting 24. For this purpose, upwardly-extending 
flanges 35 are welded to the adjoining edges of the cover plate parts on 
both sides of the upper fitting 24, and these flanges are detachably fixed 
to one another by means of bolts 23. The flanges 35 are of increased 
cross-section in the region of the fitting 24. 
The two pulley wheels 15 and 16 form a composite unit together with their 
bearings, this unit being sealed from the exterior. Each of the pulley 
wheels 15 and 16 is provided with two tapered roller bearings 37. The 
bearings 37 are made fast axially, inter alia by means of an end ring 38, 
on a sleeve 36 which surrounds the axle 17. The arrangement of the 
bearings 37 results in a large support area for the pulley wheels 15 and 
16. The pulley wheels 15 and 16 each has an inner part 40 and an outer 
part 46. Each inner wheel part 40 has a hub 41 rotatably supported on the 
sleeve 36 by the associated bearings 37. Each inner wheel part 40 also has 
a pair of annular discs 42 and 43 welded to its hub 41, and an annular web 
44 welded to the outer circumferential edges of said discs. Each inner 
wheel part 40, is therefore, a composite unitary member. Each of the 
annular webs 44 is formed with a radially-outwardly-extending flange 45. 
The hubs 41 of the two pulley wheels 15 and 16 (which, in use, rotate in 
opposite directions) are sealed with respect to one another by means of a 
metal slide-ring packing 39 having a labyrinth seal. 
Each outer wheel part 46 constitutes a wheel rim, and is of two part 
construction. The two segments of each rim 46 are identical, and each has 
an inwardly-extending flange 47. The flanges 47 of the rims 46 overlap the 
outwardly-extending flanges 45 of the corresponding inner wheel parts 40, 
and are detachably connected thereto by bolts 48. The adjoining end faces 
of the two segments of each rim 46 are connected together, for example, by 
screw-threaded members (not shown). 
The rims 46 are each formed with a circumferential groove 49. The grooves 
49 are shaped to conform with the profiled ends of the scrapers of the 
scraper assembly; but are slightly larger than these profiled ends, 
thereby permitting a predetermined amount of play. The scrapers, which are 
secured to an endless, central drive chain 50, are indicated (see FIG. 2) 
in dash-dot lines by the reference numeral 51. As shown, the profiled ends 
of the scrapers 51 engage within the grooves 49 as the scraper assembly 
passes round the curved section 13. The angle X between the upper and 
lower inclined walls which define each of the grooves 49 is slightly 
greater than the angle Y between the converging end faces of the profiled 
ends 51' of the scrapers 51. Thus, the scrapers 51 abut the rims 46 
substantially only in the regions of their outer end faces 51'. This helps 
to prevent harmful tilting moments being transmitted to the bearings 37, 
and hence reduces bearing wear. 
The axle 52 is held in the position shown by means of a retaining plate 52 
(see FIG. 2). In order to remove the pulley wheels 15 and 16 from the 
housing 14, it is necessary first to remove the retaining plate 52. When 
this has been done, the axle 17 can be withdrawn upwards, and the pulley 
wheels 15 and 16 (together with the sleeve 36, the bearings 37 and the end 
ring 38) can be removed in the direction of the arrow S (see FIG. 1). Once 
the pulley wheels 15 and 16 are free of the housing 14, their rims 46 can 
easily be removed for repair of replacement. 
Because the pulley wheels are of multi-part construction, they can be 
transported in parts, thereby reducing the size and weight of individual 
parts being moved.