GB2089756A

GB2089756A - Chain drive system

Info

Publication number: GB2089756A
Application number: GB8135491A
Authority: GB
Original assignee: Mining Supplies Minsup Pty Ltd; Mining Supplies Ltd
Current assignee: Mining Supplies Minsup Pty Ltd; Mining Supplies Ltd
Priority date: 1980-12-16
Filing date: 1981-11-25
Publication date: 1982-06-30
Also published as: GB2089756B

Abstract

A drive and tensioning/relieving arrangement 1 for a chain drive system comprises a multi-speed electric motor housed in a casing 12 connected at one side 13 thereof to a speed reduction gearbox 19 via a flexible coupling to drive at least one chain 10 at operating speed via an output shaft of the speed reduction gearbox 19, with a chain tensioning/relieving unit 25 located at the opposite side 24 of the electric motor to the flexible coupling and gearbox 19, to drive at least one chain 10 e.g. at creeping speed during chain tensioning/relieving operations, also via the output shaft of the speed reduction gearbox 19. <IMAGE>

Description

SPECIFICATION Chain drive system This invention relates to a drive and tensioning/ relieving arrangement for a system incorporating a chain drive e.g. a scraper chain conveyor or a chain of a mineral winning plough. The conveyor may be of the single strand type or of the twin strand type, with the strands inboard or outboard, the tensioning/ relieving arrangement being operable in the wellknown manner to adjust tension in the chain(s) to obviate the effect of stretch and wear that occur in service.

Conventionally, such arrangements for their drive mode have consisted of an electric motor drivably connected to a speed reduction gearbox via a fluid coupling. Demands for increased motor horsepower lead however to relatively large sized fluid couplings and the attendant disadvantages in the limited confines of a mineral face. Furthermore, should any change in the speed of the conveyor be required, it is usually necessary to remove the existing speed reduction gearbox and replace this with a gearbox having the newly required reduction ratio. For the tensioning/relieving modes, a tensioning device, incorporating a hydraulic motor, has been interposed between the motor and gearbox.

According to the present invention, a drive and tensioning/relieving arrangement for a chain drive system comprises a multi-speed electric motor connected at one side thereof to a speed reduction gearbox via a flexible coupling to drive at least one chain at operating speed via an output shaft of the speed reduction gearbox, with a chain tensioningl relieving unit located at the opposite side of the motor to the flexible coupling and gearbox to drive at least one chain during chain tensioning/relieving operations, also via the output shaft of the speed reduction gearbox.

Thus the drive and tensioning/relieving arrangement in accordance with the present invention provides for multiple operating speed drives whilst eliminating the presence of a fluid coupling, and whilst so locating the tensioning/relieving unit for ready attachment/detachment of the latter without affecting the operation of the arrangement in the drive mode.

Preferably, the electric motor is a two-speed electric motor. Conveniently, the motor output shaft is extended at the side of the motor remote from the flexible coupling and gearbox to provide a drive connection for association with the chain tensioning/ relieving unit. The latter may comprise a hydraulic motor operable on the electric motor shaft via a speed reduction gear train. In detail, a splined male/female interconnection may be provided between the extension of the electric motor shaft and an output shaft of the speed reduction train. Furthermore, a brake unit e.g. of the hydraulicallyoper- able multi-disc type, may be interposed between the hydraulic motor and the speed reduction gear train.

The chain tensioning/relieving device is operated as and when required for chain tensioning/relieving purposes, and may be brought into use by a manually displaceable device, e.g. a dog clutch, whereby a slow speed drive may be transmitted from the hydraulic motor via the speed reduction gear train, the electric motor shaft, the flexible coupling, and the speed reduction gearbox beyond that coupling, to drive the chain involved at a creeping speed for chain tensioning/relieving operatins to be effected.

The invention will now be described in greater detail, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a side elevation of a drive and tensioning/relieving arrangement applied to a drive frame of a twin outboard chain, scraper chain conveyor; and Figure 2 is a plan view of Figure 1.

In the drawing, a drive and tensioning/relieving arrangement 1 for a chain drive system in the form of a scraper chain conveyor 2 is shown mounted alongside a drive frame 3 of the conveyor. The drive frame 3 is at one end 4 attached in a conventional manner to a first line pan 5 of a series of line pans making up the desired length of the conveyor 2. At its other end 6 the drive frame 3 rotatably carries a sprocket barrel 7 rotatable about an axis 8 and having twin sprockets 9 for driving twin outboard chains 10 across which are connected scraper blades or flight bars 11 adapted to displace the coal etc.

along the conveyor.

The drive and tensioning/relieving arrangement 1 comprises a two-spaced electric motor housed in a casing 12 having at one side 13 a first output shaft 14 connected to one side of a flexible coupling 15 contained within a housing 16 which is bolted through flanges 17 to the motor casing 12 and through flanges 18 to a speed reduction gearbox 19, the other side of the flexible coupling 15 being connected to an input shaft 20 of the gearbox 19, the shaft 20, flexible coupling 15 and first output shaft 14 being rotatable about a common axis 21. In a conventional manner, the gearbox 19 is provided with a pair of bevel gears whereby the drive may be turned through 90" to drive an output shaft 22 about an axis 23 co-incident with the axis 8 of the sprocket barrel 7, the shaft 22 being drivably connected to the sprocket barrel 7.

At the other side 24 of the motor casing 12 there is mounted, by means of bolts (not shown), a chain tensioning/relieving unit 25 and the electric motor has a splined, male shaft 26, also rotatable about axis 21, extending into a correspondingly splined female transmission member (not shown) of the unit 25. The transmission member forms part of a spur gear train extending from an output sprocket 27 of a hydraulic motor 28 with a hydraulically operable, multi-disc brake unit 29 interposed between the hydraulic motor 28 and the unit 25.The hydraulic motor 28 is also provided with a directional control valve block 30 and an operating handle 31, while the unit 25 has an operating handle 32 to operate a dog-clutch (not shown) or other clutch device, to drivably connect (or disconnect) the output sprocket 27 to the shaft 26 at times when drive to the gearbox output shaft 22 from the hydraulic motor 28 is required (or is not required). Such drive is necessary occasionally to enable the chain(s) 10 of the scraper chain conveyor 2, to be tensioned and/or relieved of tension, as is necessary for instance for the repair of a broken chain 10 or broken or damaged flight bar 11. Normally howeverthe motor 28 would be inactive, and the dog clutch disengaged, with drive to the conveyor 2 being effected by the electric motor. It is obviously desirable to incorporate an interlock arrangement whereby the electric motor is isolated when the hydraulic motor 28 is required for use, and vice versa. The presence of the two-speed motor within the casing 12 ensures that the gearbox 19 need only be of a speed reduction kind rather than of the more expensive, speed change kind.

Claims

1. A drive and tensioning/relieving arrangement for a chain drive system comprising a multi-speed electric motor connected at one side thereof to a speed reduction gearbox via a flexible coupling to drive at least one chain at operating speed via an output shaft of the speed reduction gearbox, with a chain tensioning/relieving unit located at the opposite side of the motor to the flexible coupling and gearbox to drive at least one chain during chain tensioning/relieving operations, also via the output shaft of the speed reduction gearbox.

2. An arrangement as claimed in Claim 1, wherein the electric motor is a two-speed electric motor.

3. An arrangement as claimed in Claim 1 or Claim 2, wherein the motor output shaft is extended at the side of the motor remote from the flexible coupling and gearbox to provide a drive connection for association with the chain tensioning/relieving unit.

4. An arrangement as claimed in any preceding Claim, wherein the chain tensioning/relieving unit comprises a hydraulic motor operable on the electric motor shaft via a speed reduction gear train.

5. An arrangement as claimed in Claim 4, wherein a splined male/female interconnection is provided between the extension of the electric motor shaft and an output shaft of the speed reduction train.

6. An arrangement as claimed in Claim 4 or Claim 5, wherein a brake unit is interposed between the hydraulic motor and the speed reduction gear train.

7. An arrangement as claimed in Claim 6, wherein the brake unit is of the hydraulically operable multi-disc type.

8. An arrangement as claimed in any preceding Claim, wherein the chain tensioning/relieving device is operated as and when required for chain tensioning/relieving purposes by a manually displaceable device.

9. An arrangement as claimed in Claim 8, wherein the manually displaceable device is a dog clutch.

10. A drive and tensioning/relieving arrangement for a chain drive system, substantially as hereinbefore described with reference to the accompanying drawings.