GB2127127A

GB2127127A - Drive chain

Info

Publication number: GB2127127A
Application number: GB08323803A
Authority: GB
Inventors: Dieter Grundken; Manfred Redder; Reinhold Bruggemann
Original assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Current assignee: Gewerkschaft Eisenhutte Westfalia GmbH
Priority date: 1982-09-15
Filing date: 1983-09-06
Publication date: 1984-04-04
Also published as: GB2127127B; FR2533008B1; GB8323803D0; FR2533008A1; DE3234137A1; DE3234137C3; DE3234137C2

Abstract

A drive chain for a scraper-chain conveyor comprises alternate horizontal links 1 and vertical links 2. Each horizontal link 1 has a constant circular cross-section 3, and each vertical link 2 has a pair of parallel, longitudinally- extending portions 4, each having a flattened (preferably an oval or elliptical) cross-section. The longitudinally- extending portions 4 of each vertical link 2 are connected by a pair of arcuate web portions 6 of circular cross-section. <IMAGE>

Description

SPECIFICATION Drive chain This invention relates to a drive chain for a mineral mining installation such as a scraper-chain conveyor.

Chains are used in mining operations, particularly as drive chains for ploughs and scraper-chain conveyors. Such drive chains have links of circular cross-section, that is to say their links are made from metal of circular cross-section. Thus, throughout this specification, the term "cross-section" whenever used to qualify the shape of a chain link should be construed accordingly. Scraper-chain conveyors used in underground mining operations may have a single, central drive chain, to which the scrapers are attached at their mid-portions (a single, centre-chain conveyor), two parallel drive chains to which the scrapers are attached at their mid-portions (a double, centre-chain conveyor), or two parallel drive chains to which the scrapers are attached adjacent to their ends (a double, outboard-chain conveyor).The increasing lengths of high-output longwall workings lead to constantly increasing power requirements for scraper-chain conveyors, and therefore to drive chains of increasing strength and weight. High power requirements are also imposed in the case of known conveyors for negotiating curves, for example where a scraper assembly has to be deflected through roughly 90 at a roller curve.

The use of drive chains having links of circular cross-section is limited by the dimensions of the conveyor channel sections (pans). Thus, it is inconvenientforthevertical chain links to project too far above the floor of the conveyor. As the drive chain(s) pass beneath the floor on the return run, an excessive vertical chain dimension can lead to the entire conveyor having to be jacked up to provide sufficient space between the lower (return) run of the chain(s) and the conveyor floor to permit passage of the chain(s).

The aim of the invention is to provide a drive chain which has a smaller vertical dimension than known chains, without involving excessive manufacturing costs, and which can provide a considerably increased tractive force, whilst its chain links have the ability to deflect in order to pass round chain sprockets or a roller curve.

The present invention provides a drive chain for a mineral mining installation, the drive chain having a plurality of first links alternating with a plurality of second links, each of the first links having a constant circular cross-section, and each of the second links having a pair of parallel longitudinally-extending portions and a pair of arcuate end portions interconnecting the longitudinally-extending portions, wherein the longitudinally-extending portions of each second link each have a flattened cross-section, and the arcuate end portions of each second link each have a circular cross-section.

When this drive chain is used for a scraper-chain conveyor, the first links are horizontal, and the second links are vertical.

Preferably, the major axis of each longitudinallyextending portion of each second link has a length that is greater than the diameter of the circular cross-section of each first link, and the minor axis of each longitudinally-extending portion of each second link has a length that is smaller than the diameter of the circular cross-section of each first link.

Because of the flattening of the longitudinallyextending portions of its second (vertical) links, such a chain has a high hauling capacity, whilst having a considerably reduced vertical dimension compared with the existing chains having both horizontal and vertical links of circular cross-section. Thus, such a chain can be used as a drive chain for a scraperchain assembly which has an increased haulage capacity, without the need for the channel sections of the conveyor to have increased dimensions.

Preferably, the diameter of the circular crosssection of each arcuate end portion of each second link is equal to the diameter of the circular crosssection of each first link, so that the links of the chain can still deflect to a sufficient extent.

Advantageously, the first and second links have the same overall size. The second (vertical) links can therefore, be made (without excessive cost) from the links of circular cross-section which are used for the first (horizontal) links. Preferably, this is achieved by flattening the parallel longitudinal portions of the second links by means of a pressing or upsetting operation.

Advantageously, the pitch of each second link is the same as that of each first link. Conveniently, the distance between the adjacent surfaces of the longitudinally-extending portions of each second link is approximately equal to, or slightly smallerthan, the distance between the corresponding longitudinallyextending portions of each first link.

The longitudinally-extending portions of the second links may each have an approximately oval, half-oval or elliptical cross-section. Advantageously, the longitudinally-extending portions of the second links are delimited at the outside and inside by parallel planar surfaces, the ends of which are interconnected by arcuate surfaces forming part of the associated arcuate end portions.

Advantageously, the ratio of the length of the major axis of each longitudinally-extending portion to that of the minor axis of that longitudinallyextending portion is between 1.5:1 and 2.5:1. Prefer ably, this ratio is between 1.7:1 and 1.9: 1 1.9:1.Such a chain occupies approximately 20 to 30 % less space than existing chains of this type, whilst providing the same tractive force.

Chains constructed in accordance with the invention are particularly useful as drive chains for scraper-chain conveyors; and especially in centrechain scraper-chain conveyors which can be deflected round roller curves. Moreover, such chains can also be used in underground winning installations, and particularly as plough drive chains which are moved, in the usual manner, in chain-guide ducts associated with a plough guide.

A scraper-chain conveyor drive chain constructed in accordance with the invention will now be described, by way of example, with reference to accompanying drawings, in which: Figure 1 is a perspective view of part of the drive chain; Figure 2 is a cross-sectional view seen in the direction of the arrow Il shown in Figure 1; Figure 3 is a plan view of part of the drive chain of Figure 1; and Figures 4 and 5 show two modified cross-sectional forms of the longitudinally-extending portions of the vertical links of the drive chain shown in Figures 1 to 3.

Referring to the drawings, Figure 1 shows a scraper-chain conveyor drive chain comprising alternate horizontal links 1 and vertical links 2. The horizontal links 1 correspond to those of a normal chain, each having a constant circular cross-section 3.

Each of the vertical chain links 2 has a pair of parallel longitudinally-extending portions 4, and a pair of arcuate end portions 6 interconnecting the longitudinal portions 4. The arcuate end portions 6 have a circular cross-section corresponding to that of the horizontal links 1, whereas the longitudinal portions 4 are of flattened cross-section 5 compared to this circular cross-section. This arrangement can be seen best in Figure 3, which shows the changeover zone 7 from the circular cross-section arcuate end portions 6 to the broader, flattened longitudinal portions 4. As shown in Figure 2, the horizontal axis of each of the flattened cross-sections 5 of the two longitudinal portions 4 has a length L that is greater than the diameter D of the circular cross-section 3 of the horizontal links 1.The vertical axis of the flattened cross-section 5 of each of the longitudinal portions 4, on the other hand, has a length H which is smaller than the diameter D.

Both the horizontal links 1 and the vertical links 2 have the same overall size. Accordingly, the arcuate end portions 6 of the vertical links 2 have the same diameter D as the horizontal links 1. Moreover, the horizontal links 1 and the vertical links 2 have the same pitch t. The internal width b2 of each vertical link 2 is at least approximately equal to the internal width b1 of each horizontal link 1. It may, however, be siightly (for example approximately one to two millimetres) smaller than the latter.

As shown in Figures 1 and 2, the cross-section 5 of the horizontal longitudinal portions 4 of the vertical links 2 is of at least roughly oval shape. It is delimited at its outer and inner faces by parallel flat surfaces 8 and 9, the end of which are interconnected by arcuate faces 10.

It would also be possible for the cross-sectional faces 5 of the horizontal longitudinal portions 4 of the vertical links 2 to be approximately half-oval, as shown in Figure 4, or roughly elliptical, as shown in Figure 5.

The ratio of the length of the horizontal (major) axis of the flattened cross-section 5 of the longitudinal portions 4 to that of its vertical (minor) axis, that is to say the ratio L:H, is expediently between 1.5:1 and 2.5:1 and preferably between 1.7:1 and 1.9:1.

The vertical links 2 of the chain 1 are expediently produced from links of circular cross-section. Consequently, the vertical links 2 can be made by modifying the shape of the horizontal links 1. Such a shaping operation is carried out on the two longitudinal portions 4 of these chain links, so as to provide the required flattened cross-section 5.

Claims

1. A drive chain for a mineral mining installation, the drive chain having a plurality of first links alternating with a plurality of second links, each of the first links having a constant circular crosssection, and each of the second links having a pair of parallel longitudinally-extending portions and a pair of arcuate end portions interconnecting the longitudinally-extending portions, wherein the longitudinally-extending portions of each second link each have a flattened cross-section, and the arcuate end portions of each second link each have a circular cross-section.

2. A drive chain as claimed in claim 1, wherein the major axis of each longitudinally-extending portion of each second link has a length that is greater than the diameter of the circular crosssection of each first link, and wherein the minor axis of each longitudinally-extending portion of each second link has a length that is smaller than the diameter of the circular cross-section of each first link.

3. A drive chain as claimed in claim 1 or claim ?, wherein the first and second links have the same overall size.

4. A drive chain as claimed in any one of claims 1 to 3, wherein the longitudinally-extending portions of the second links each have an approximately oval, half-oval or elliptical cross-section.

5. A drive chain as claimed in any one of claims 1 to 4, wherein the longitudinally-extending portions of the second links are delimited at the outside and inside by parallel planar surfaces, the ends of which are interconnected by arcuate surfaces forming part of the associated arcuate end portions.

6. A drive chain as claimed in any one of claims 1 to 5, wherein the ratio of the length of the major axis of each longitudinally-extending portion to that of the minor axis of that longitudinally-extending portion is between 1.5:1 and 2.5:1.

7. A drive chain as claimed in claim 6, wherein said ratio is between 1.7:1 and 1.9:1.

8. A drive chain as claimed in any one of claims 1 to 7, wherein the diameter of the circular crosssection of each arcuate end portion of each second link is equal to the diameter of the circular crosssection of each first link.

9. A drive chain as claimed in any one of claims 1 to 8, wherein the pitch of each second link is the same as that of each first link.

10. A drive chain as claimed in any one of claims 1 to 9, wherein the distance between the adjacent surfaces of the longitudinally-extending portions of each second link is approximately equal to, or slightly smaller than, the distance between the corresponding longitudinally-extending portions of each first link.

11. A drive chain substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 3, Figures 1 to 3 as modified by Figure 4, or Figures 1 to 3 as modified by Figure 5 of the accompanying drawings.