Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1999-09-21
2001-08-28
Ellis, Christopher P. (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
Reexamination Certificate
active
06279734
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a chain drum arrangement for a drive and/or reversing station of a scraper-chain conveyor, used in particular in mining.
BACKGROUND OF THE INVENTION
Scraper-chain conveyors are frequently used, in particular, in mining as face or gate conveyors and also for debris haulage during tunnel driving. The scraper-chain assembly of the conveyor, typically designed as a centre-strand assembly, is driven continuously through one or two chains connected to spaced-apart scrapers moving along in upper and lower runs in the central region of the conveyor troughs or pans. The scraper-chain assembly is entrained around chain drums which are mounted in machine frames arranged on the conveyor troughs at the ends of the conveyor. The chain drum at the discharge end of the conveyor is usually driven by a main conveyor drive flanged laterally on the machine frame to form a drive station. At the other end of the conveyor, the drum forms a reversing station which can comprise a further (auxiliary) drive, but can frequently also be without a drive, in particular in the case of conveyors with relatively small lengths.
During operation, the chain drums of these arrangements are exposed to very high stresses and therefore wear rapidly. In particular, the sprocket wheels which mesh with the chain or chains wear very rapidly so it is necessary to design the chain drums in such a way that they can easily be removed and exchanged whenever necessary.
A known chain drum arrangement disclosed in DE-OS 42 04 381 has a chain drum which together with its short stub shaft, can be removed from the drive assembly after the release of screw bolts placed transversely through the shaft and holding the drum arrangement in the machine frame. With this arrangement, therefore, the chain drum is always exchanged together with its shaft, and this constructional unit is comparatively heavy and correspondingly difficult to handle. The arrangement has the further drawback that it necessitates time-consuming alterations if only the chain drum is to be replaced by a new one and the chain drum shaft with its bearing is to be retained.
With a chain drum arrangement known from DE-AS 1 756 355, the chain drum can also be removed together with its shaft and the rolling bearings arranged thereon from the machine frame. For this purpose, the rolling bearings are received in the machine with divided carrying rings. One ring half has to be dismantled and removed from each bearing before the drum arrangement can be exchanged. The use of divided carrying rings is disadvantageous in view of the high load stresses which tends to cause premature wear of the bearing carrying rings. The unit composed of the drum, shaft and bearings is also subject to the same disadvantages as described hereinbefore with respect to the high weight of the unit which is to be exchanged and the additional assembly cost for exchanging the bearings in the dismantled state of the chain drum.
DE-OS 195 47 351 discloses a drive station for scraper-chain conveyors with a chain drum coupled to two drive shafts mounted in the machine frame. The chain drum shafts are mounted axially displaceably in the machine frame. At their leading ends projecting from the machine frame, the shafts have teeth with which they engage in an internal bore, provided with mating internal teeth, at the respective end face of the chain drum. For unlocking, the chain drum shafts are displaced axially in the machine frame so that the shaft ends engaging in the chain drum during operation are removed from the internal bore and are moved back into the machine frame so the entire chain drum can then be removed from the machine frame transversely to its axis. Although this known arrangement allows very simple and quick exchange of the chain drum, the displaceable mounting of the chain drum shafts is comparatively complicated and therefore expensive and susceptible to breakdown.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a chain drum arrangement which allows simple exchange of the single-part chain drum without the bearings and/or shafts of the arrangement having to be removed from the machine frame and with which the complicated axially displaceable mounting of the chain drum shafts can be dispensed with.
According to the invention there is provided a chain drum arrangement for a drive or reversing station of a scraper-chain conveyor, in particular for use in mining; said arrangement comprising a releasable chain drum which is connected at its end regions to two mutually aligned chain drum shafts mounted rotatably in a machine frame and, when uncoupled, can be removed from its fitted position in the machine frame or inserted into the fitted position transversely to its longitudinal axis; wherein the chain drum shafts have terminal shaft journals projecting inwardly from the machine frame and the chain drum is provided, at its end regions, with substantially radially extending plug-in elements with which it can be plugged onto the shaft journals and locked non-rotatably thereto.
In a particularly advantageous development of the invention, the plug-in elements are pockets which are open radially at least on the outside and into which the shaft journals engage during assembly and in which they are locked during operation of the conveyor.
It is particularly advantageous if the shaft journals are peripherally flattened and engage positively in the pockets. With this development of the invention, the shaft journals and the drum therefore form interengageable projection-and-recess elements with the pockets than acting as the associated recesses. In contrast to known designs these projections and recesses are not orientated parallel to the shaft axis as with shaft and hub joints but extend transversely thereto.
The pockets preferably possess undercut regions into which the shaft journals fit positively with their radially outer external regions forming locking claws after the chain drum has been plugged onto the shaft journal and rotated about a predetermined rotational angle. This connection between the chain drum shaft journal and the chain drum resembles a bayonet fitting and allows extremely rapid removal and installation of the drum because the positive connections between the shaft journals and chain drum is produced easily by moving the drum transversely to the axis of rotation and subsequent rotation about the set rotational angle, for example about approximately 60°. The chain drum can also be centred via the bayonet-type fitting, for which purpose the locking claws expediently have a curved external face whereas the undercut regions form segments of a circle of which the radius corresponds to the radius of curvature of the external faces of the locking claws. This design ensures that the chain drum rests without backlash and exactly centred on the shaft journal even after rotation about a small rotational angle.
The undercut regions advantageously form radially extending stop faces against which the locking claws rest with contact faces extending radially to the shaft axis after application and rotation of the chain drum. This design ensures that the torque between the chain drum and the chain drum shafts, which normally has to be transmitted only in one rotational direction of the chain drum, is transmitted only via the stop and contact faces, the plane of contact extending through the axis of rotation of the shafts or the drum so that the desirable load of a pure moment exists without additional eccentrically acting forces.
The chain drum can be arrested on the shaft journals by means of a suitable securing means, which does not transmit forces itself but serves merely to prevent unintentional rotation of the chain drum relative to the shaft journals and therefore undesirable release of the connection between the relative rotatable parts. Each shaft journal is expediently allocated a separate securing means which can consist essentially of a closure member inserted into the radial opening of the pocket associated with the jou
Merten Gerhard
Meya Hans
DBT Deutsche Bergbau--Technik GmbH
Ellis Christopher P.
Samuels Gauthier & Stevens
Tran Khoi H.
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