GB2156943A - Sprocket/barrel assembly for a scraper chain conveyor - Google Patents

Abstract

A sprocket/barrel assembly 1 for a scraper chain conveyor 32, comprising at least one outer barrel 4, a coaxial, inner shaft 8, located at least partially within the barrel(s) 4, at least one sprocket ring 7, carried either by the shaft 8, or by the barrel 4, and bearing means 11 located between the barrel(s) 4, and the shaft 8, whereby one is rotatable with respect to the other one. The invention also includes a head or tail frame for a scraper a chain conveyor incorporating such an assembly, and also a scraper chain conveyor incorporating such a head frame. <IMAGE>

Description

SPECIFICATION Sprocket/barrel Assembly, Frame and Conveyor This invention relates to a sprocket/barrel assembly, to a frame incorporating such an assembly, and to a scraper chain conveyor incorporating such a frame.

Such conveyors are used extensively in coal mining operations, and may be of a kind having twin, outboard strands of round link chain, across which strands transversely extending scraper blades or flight bars are attached, or alternatively may be of the single or twin centre strand type, again with transverse flight bars. With either arrangement, the conveyor is built up to the desired length by securing together, end-to-end, a plurality of line pans of unit length, with respective ends of the conveyor, e.g. a head end and a tail end, defined by a head frame and a tail frame, each incorporating a sprocket/barrel adapted to engage the chain(s), with at least the sprocket/barrel of the head frame usually being driven.Conventionally, each frame comprises a pair of upstanding sidewalls which are spaced apart by the width of the particular conveyor involved, with each sidewall provided with a drilled hole in which a bearing is fitted for rotatably supporting a shaft (being a drive shaft in the case of a driven sprocket/barrel assembly) of the sprocket/ barrel, to which shaft a chain-engaging, sprocket/ barrel is attached. Bearing maintenance, lubrication or servicing is nottoo difficult a problem in respect of the goaf side sidewall (i.e. the sidewall that is located remotely from the mineral face involved), for limited access is available, but failures frequently occur at the bearing of the face side sidewall, and it is difficult, if not impossible to gain adequate access to this bearing.Furthermore, demands to provide ever increasing horsepowers has led to bearing sizes necessarily being increased for specific frame size, but again as far as the face side bearing is concerned, projection of that over sized bearing beyond the sidewall frequently results in the bearing fouling movements of the mineral winning machine, or of any ranging arm/cutting head of the mineral winning machine. Consequently, a frequently used solution, in the case of a twin outboard strand conveyor, to avoid an over sized bearing projecting beyond the face side sidewall, is to have the bearing project inwardly, and to provide space for such projection by coring out the adjacent sprocket ring, but this results in loss of strength of the sprocket ring.With the constraints placed upon the space available to accommodate bearings, an increase in the axial dimension of a bearing correspondingly reduces the space available for the conventionally provided bearing seals, resulting in less efficient seals being employed than would otherwise be the case. In addition, the deliberate weakening of a sprocket ring to accommodate a projecting bearing frequently leads to premature sprocket ring failure, especially if the sprocket ring is already subject to a high rate of wear because worn chain(s) is being used on the conveyor, and a failed sprocket results in halting of the conveyor and total loss of mineral production until such time as repair can be effected, this being an extremely tedious operation, especially in a mining environment.

According to a first aspect of the present invention, there is provided a sprocket/barrel assembly for a scraper chain conveyor, comprising at least one barrel, a co-axial, inner shaft located at least partially within the barrel(s), at least one co-axial sprocket ring carried either by the shaft or by the barrel(s), and co-axial bearing means located between the barrel(s) and the shaft, whereby one is rotatable with respect to the other one.

According to a second aspect of the present invention, there is provided a head or tail frame for a scraper chain conveyor, provided with a sprocket/ barrel assembly as defined above.

According to a third aspect of the present invention, there is provided a scraper chain conveyor incorporating a head frame in accordance with the second aspect of the invention at a head end of the conveyor, and/or a tail frame in accordance with the second aspect of the invention, at a tail end of the conveyor.

Thus, the sprocket/barrel assembly, head or tail frame, and conveyor in accordance with the various aspects of the invention provide a construction in which bearings are no longer carried by the spacedapart sidewalls of the head or tail frame, but on the contrary are provided inboard of these sidewalls, by being located between the barrel(s) and the shaft.

Such a construction is free of the space constraints placed upon sidewall-housed bearings and consequently enables bearings of relatively large dimensions, which can comfortably accommodate the loads involved, to be incorporated. Similarly, adequately dimensioned seals may also be provided. It follows that with the construction in accordance with the various aspects of the invention, firstly there is no projection of any bearing beyond the face side sidewall and secondly there is no need to core and thereby weaken a sprocket ring to accommodate a projecting portion of the bearing.

In a first embodiment, the assembly may comprise two spaced apart sprocket rings and one central barrel interposed between the rings so that one ring is located adjacent each barrel end. In a second embodiment, the assembly may comprise two spaced apart barrels, with a central sprocket ring (for either single or twin centre strand chains) interposed between the barrels, so that one barrel is located adjacent each sprocket side. It will be appreciated that the first embodiment is intended for a conveyor of the twin outboard strand type and the second embodiment is intended for a conveyor of the centre strand (single or twin) type. Preferably, the bearing means is one or more roller bearing(s).

Thus, in the first assembly embodiment, whether intended to be driven or non-driven, a roller bearing is provided towards each end of the barrel, between the barrel and the shaft. In the second assembly embodiment, whether intended to be driven or non-driven, a roller bearing is provided between each barrel and the shaft. In the case of a driven assembly, the shaft is a drive shaft and the sprocket ring(s) is drivably carried by the drive shaft, while the barrel(s) is non-rotatable, in contrast to all prior art proposals where the barrel rotates with the sprocket ring(s). Thus, the external periphery of the barrel constitutes a slide surface or guide track for the flight bars as they pass from the conveying run into the return run of conveyor, and preferably has the same external diameter as, or of smaller external diameter than, a conventional rotary barrel.

In the case of a non-driven assembly, the shaft is a non-driven shaft, while either the shaft or the barrel(s) carries the sprocket ring(s) and is rotatable with the sprocket ring(s).

Conventionally, it is usual for the conveyor head end to be driven, while the tail end may be driven or free-running, but irrespective of whether the assembly is a driven or non-driven, a two-part bearing seal is preferably provided adjacent the bearing means with one bearing seal half carried by the rotatable member (shaft, sprocket ring or barrel) and the other bearing seal half carried by the stationary member (shaft or barrel), with portions of the seal halves in rotatable, sealing engagement with one another.

With some sprocket/barrel assemblies in accordance with the invention, it is also preferred for the shaft to be hollow, so as to define a reservoir for lubricating oil, with oil conveying passageways extending from the reservoir to the bearings.

The head or tail frame preferably comprises a pair of spaced-apart, parallel sidewalls, wherein each end of each sidewall is provided with a recess to receive end portions of the shaft (whether driven or non-driven) orthe barrel(s). In detail,fora driven shaft, each recess may be constituted by a slot of width slightly exceeding the diameter of a portion of the shaft to be received in the slots. For a non-driven shaft, the recess may be semi-circular, with a releasable clamp, also having a semi-circular recess, serving to clamp the shaft portion to the sidewall.

For an assembly with a non-rotatable barrel, the barrel(s) is releasably attached to, and supported from, the frame. In detail, the frame may be provided with two or more spaced apart, arcuate surfaced, location recesses, of curvature corresponding to that of the external periphery of the barrel(s), and the latter may be urged into seating relationship with the recesses by attaching to the barrel(s) a stud, or a pair of spaced apart studs, e.g. by welding or screwing the stud(s) to the barrel(s), with the stud shanks passing through plain holes in a transverse bearing plate of the frame, and with a nut on the or each stud shank beyond the bearing plate to react on the latter to pull the barrel(s), via the stud(s), into firm seating engagement with the location recesses.With a stationary barrel(s), deck plate portions of the frame may, if required, be attached to, or at least abut against, the barrel(s).

A drivable shaft conveniently has a portion which projects beyond one sidewall. The projecting portion may, in the case of a driven assembly carry a portion of a gear coupling for connection to a drive transmission. If it is required to use "driven" components in a non-driven mode, the projecting shaft portion may be obscured by a dished cover attached to the adjacent sidewall.

It is of course necessary in the case of a scraper chain conveyor incorporating a frame having a driven sprocket/barrel assembly, to support the barrel(s), or in the case of a non-driven sprocket/ barrel assembly to support the either the barrel(s) or the shaft, from the frame from within the "loop" of the conveyor chain(s).

The invention will now be described in greater detail, by way of examples, with reference to the accompanying drawings in which: Figure lisa part sectional plan view of a first embodiment of driven sprocket/barrel assembly; head/tail frame and conveyor in accordance with the invention; Figure 2 corresponds to Figure 1, but shows a second embodiment; Figure 3 is a side elevation of both Figures 1 and 2; Figure 4 corresponds to Figure 1, but show a first embodiment of non-driven sprocket/barrel assembly and head/tail frame, in which the barrel(s) is non-rotatable; Figure 5 corresponds to Figure 2 but shows a second embodiment of non-driven sprocket/barrel assembly and head/tail frame, in which the barrel(s) is non-rotatable; and Figure 6 corresponds to Figure 4 but shows an embodiment in which the shaft is non-rotatable.

In all the Figures is illustrated a sprocket/barrel assembly 1, constituting the first aspect of the invention, mounted in a head or tail frame 2, constituting the second aspect of the invention, to form part of a scraper chain conveyor 3, constituting the third aspect of the invention.

In Figure 1, the assembly 1 is for a twin, outboard strand scraper chain conveyor and consequently the assembly comprises one central barrel 4 having a circular external periphery 5 and ends 6, the barrel 4 being interposed between two spaced-apart sprocket rings 7. The latter are drivably mounted e.g., by a splined or keyed connection, on a shaft8 rotatable about a longitudinal axis 9 by means of a conventional gear coupling 10 (the coupling ring not being illustrated), one half 10A of the coupling being shown in Figure 1 and both halves 10A, 10B being shown in Figure 2, the half 10B being mounted on an output shaft, also rotatable about axis 9, of a gearbox of a drive transmission from a power source e.g., an electric motor. As indicated in the drawing, the shaft 8 is machined to different diameters along its length to suit different requirements. Towards each end 6 of the barrel 4 a roller bearing 11 is located between the barrel 4 and the shaft 8, so that the shaft 8, and consequently the sprocket rings 7, are rotatable with respect to the non-rotatable barrel 4. In the embodiment of Figure 1, the barrel 4 is provided with a pair of spaced apart studs 12, with ends 13 of the studs being screw threaded to receiving a nut 14 and washer 15.

Adjacent each bearing 11 is located a two-part face seal 16.

The frame 2 is a head or tail frame depending on whether the frame is located at the head end ortail end of the conveyor 3, the frame 2 comprising a pair of parallel, spaced apart sidewalls 17, each end 18 of each sidewall being provided with a slot 19 with a semi-circular end profile 19A, each slot 19 being of width slightly exceeding the diameters of portions 8A of the shaft 8 to be located in each slot, so that, during installation into, or removal from, a frame 2, the assembly 1 can be rolled along the slots 19. The sidewalls 17 are inter-connected by a transverse plate 20, which carries a pair of spaced apart, parallel plates 21 projecting towards the axis 9 and each provided with an arcuate surfaced, location recess 22 of curvature corresponding to that of the external periphery 5 of the barrel 4.The plates 21 are inter-connected by a transverse bearing plate 23 provided with two spaced apart plain holes 24 of dimensions capable of receiving a stud 12 so that, with the studs 12 passed through the holes 24 and the washers 15 and nuts 14 applied, the barrel periphery 5 is brought into tight seating engagement with the arcuate surface recesses 22, upon tightening of the nuts 14 against the bearing plate 23. Between each plate 21 and adjacent sidewall 17 is located a transverse plate 25 provided with a slot 26 to receive a support stud 27 of a chain stripper 28 of each sprocket ring 7. With the driven embodiment of Figure 1, the barrel 4 is stationary, and as best seen in Figure 3, upper and lower deck plate portions 29 and 30 respectively of the frame 2 are carried by the plates 20,21, and abut against the barrel periphery 5.

In the embodiment of Figure 2 is indicated an assembly for use with a twin centre strand chain, and comprises a central sprocket ring at 7, to each side of which is provided a stationary barrel 4. The barrel periphery 5 is supported against a location recess 22 in a pair of parallel plates 21A, which are welded to a bearing plate 23A. One bearing 11 is provided within each barrel 4, between the barrel 4 and the shaft 8. Each barrel 4 is provided with a single stud 12 passed through a hole 24 in a bearing plate 23A.

As best seen in Figure 3, the sprocket/barrel assembly 1 is supported in the frame 2 within the "loop" of chain(s) 31 of the conveyor 3, the chain lines being indicated at 32 in all embodiments, the "loop" being defined between the upper conveying run 33 of the conveyor 3, and the lower return run 34 of the conveyor 3, after the chain(s) 31/32 is looped around the sprocket(s) 7 and barrel(s) 4.

The embodiments of Figures 1 to 3 illustrate sprocket/barrel assemblies 1 intended to be driven.

However, at conveyor tail ends, it is sometimes a requirement that the assembly be non-driven, i.e. be free-wheeling. This may readily be achieved with the assemblies and frames in accordance with the invention. Thus, to keep manufacturing costs to a minimum, the Figure 1 and Figure 2 embodiments could be modified quite simply to a free-wheeling mode, by removing the gear coupling half 1 OA and applying a cover plate 10C illustrated in chain dotted line in Figure 1, thereby using in a non-driven mode the same components as are used in a driven assembly/frame.

However, in Figure 4 is illustrated a non-driven arrangement, with specially constructed components. Thus, shaft 8 does not pass beyond a sidewall 17 but end caps 35, secured by screwed studs 36, are applied to each end of the shaft to retain the adjacent sprocket ring 7 on the shaft, while cover plates 37 are inserted into the slots 19, and secured, the end caps 35 also being used for the roll-in, roll-out facility, along the slots 19.

In the embodiment of Figure 5, removeable end caps 35 of the barrels 4 are formed with projecting circular portions 38, to provide the roll-in, roll-out facility.

In the embodiment of Figure 6, the shaft 8 is non-rotatable and is located in semi-circular profiles 19A in the sidewalls 17, being secured in the holes by clamping plates 39, also provided with a semicircular recess 40, and secured by bolts to the adjacent sidewall 17. Each sprocket ring 7 is secured e.g. by welding to a central barrel 4, with the barrel, and hence the sprocket rings, rotatably mounted on the shaft 8 by means of roller bearings 11, one towards each end 6 of the barrel 4.

Claims (39)

1.A A sprocket/barrel assembly for a scraper chain conveyor, comprising at least one barrel, a co-axial, inner shaft located at least partially within the barrel(s), at least one sprocket ring carried either by the shaft or by the barrel(s), and bearing means located between the barrel(s) and the shaft, whereby one is rotatable with respect to the other one.

2. An assembly as claimed in Claim 1, comprising two spaced apart sprocket rings and one, central barrel interposed between the rings so that one ring is located adjacent each barrel end.

3. An assembly as claimed in Claim 1, comprising two spaced apart barrels, and a central sprocket ring interposed between the barrels, so that one barrel is located adjacent each sprocket side.

4. An assembly as claimed in any preceding Claim, wherein the bearing means is one or more roller bearing(s).

5. An assembly as claimed in Claim 4, when appendantto Claim 2, comprising a roller bearing towards each end of the barrel, between the barrel and the shaft.

6. An assembly as claimed in Claim 4, when appendantto Claim 3, comprising a roller bearing between each barrel and the shaft.

7. An assembly as claimed in any preceding Claim, wherein the shaft is a drive shaft and the sprocket ring(s) is drivably carried by the drive shaft, while the barrel(s) is non-rotatable.

8. An assembly as claimed in any one of Claims 1 to 6, wherein the shaft is a non-driven shaft, while either the shaft or the barrel(s) carries the sprocket ring(s) and is rotatable with the sprocket ring(s).

9. An assembly as claimed in any preceding Claim, wherein, a two-part bearing seal is preferably provided adjacent the bearing means, with one bearing seal half carried by the rotatable member and the other bearing seal half carried by the stationary member, with portions of the seal halves in rotatable, sealing engagement with one another.

10. An assembly as claimed in any preceding Claim, wherein the shaft is hollow, so as to define a reservoir for lubricating oil, with oil conveying passageways extending from the reservoir to the bearings.

11. A head or tail frame for a scraper chain conveyor provided with a sprocket/barrel assembly as defined in any preceding Claim.

12. A frame as claimed in Claim 11, comprising a pair of spaced-apart, parallel sidewalls, wherein each end of each sidewall is provided with a recess, to receive end portions of the shaft.

13. Aframe as claimed in Claim 12, wherein the recess is a slot of width slightly exceeding the diameter of a portion of the shaft to be received in the slots.

14. A frame as claimed in Claim 12, wherein the recess is semi-circular, with a releasable clamp, also having a semi-circular recess, serving to clamp the shaft portion to the sidewall.

15. Aframe as claimed in Claim 12 or Claim 13, wherein, for an assemblywith a non-rotatable barrel(s), the barrel(s) is releasably attached to, and supported from, the frame.

16. A frame as claimed in Claim 15, provided with two or more spaced apart, arcuate surfaced location recesses, of curvature corresponding to that of the external periphery of the barrel(s).

17. A frame as claimed in Claim 16, wherein the barrel(s) is urged into seating relationship with the recesses by attaching to the barrel(s) a stud, or a pair of spaced apart studs, with the stud shanks passing through plain holes in a transverse bearing plate of the frame.

18. Aframe as claimed in any one of Claims 11 to 17, wherein deck plate portions oftheframe are attached to, or abut against, the barrel(s).

19. A frame as claimed in any one of Claims 1 to 18, wherein the shaft has a portion which projects beyond one sidewall.

20. Aframe as claimed in any one of Claims 1 to 19, wherein the projecting shaft portion carries a portion of a gear coupling connectable to a drive transmission, in the case of a driven frame.

21. A frame as claimed in Claim 20, wherein the projecting shaft portion is obscured by a dished cover attached to the adjacent sidewall, in the case of an assembly employing driven components in a non-driven mode.

22. A scraper chain conveyor incorporating a head frame as defined in any one of Claims 11 to 21, at a head end of the conveyor.

23. A scraper chain conveyor incorporating a tail frame as defined in any one of Claims 11 to 21, at a tail-end of the conveyor.

24. A scraper chain conveyor as claimed in Claim 22 or Claim 23, wherein the sprocket/barrel assembly is supported within the "loop" of the conveyor chains.

25. A sprocket/barrel assembly substantially as hereinbefore described with reference to Figures 1 and 3 of the accompanying drawings.

26. A sprocket/barrel assembly substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

27. A sprocket/barrel assembly substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.

28. A sprocket/barrei assembly substantially as hereinbefore described with reference to Figures 3 and 5 of the accompanying drawings.

29. A sprocket/barrel assembly substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.

30. A frame for a scraper chain conveyor, substantially as hereinbefore described with reference to Figures 1 and 3 of the accompanying drawings.

31. A frame for a scraper chain conveyor, substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

32. A frame for a scraper chain conveyor, substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.

33. A frame for a scraper chain conveyor, substantially as herein before described with reference to Figures 3 and 5 of the accompanying drawings.

34. Aframe for a scraper chain conveyor, substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.

35. A scraper chain conveyor substantially as hereinbefore described with reference to Figures 1 and 3 of the accompanying drawings.

36. A scraper chain conveyor substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

37. A scraper chain conveyor substantially as hereinbefore described with reference to Figures 3 and 4 of the accompanying drawings.

38. A scraper chain conveyor substantially as hereinbefore described with reference to Figures 3 and 5 of the accompanying drawings.

39. A scraper chain conveyor substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.