GB2034269A

GB2034269A - Scraper Chain Conveyors

Info

Publication number: GB2034269A
Application number: GB7936648A
Authority: GB
Original assignee: Wheway Watson Holdings Ltd
Current assignee: Mann and Hummel Wheway Ltd
Priority date: 1978-11-09
Filing date: 1979-10-23
Publication date: 1980-06-04
Also published as: GB2034269B

Abstract

In a scraper bar chain conveyor, a scraper bar assembly (10) comprises a scraper bar (10a) and a clamping block (21) between which a link (17) of a chain (15) to which the scraper bar assembly (10) is to be attached, is entrapped. The clamping block (21) is secured to the scraper bar (10a) by elongate coupling pins (23) which extend parallel to the scraping face (28) of the bar (10a). <IMAGE>

Description

SPECIFICATION Improvements Relating to Scraper Bar Chain Conveyors This invention relates to scraper bar assemblies of the type hereinafter referred to as the type described for use in scraper bar chain conveyors of the kind hereinafter referred to as of the kind specified, comprising a conveyor surface and a plurality of scraper bar assemblies in scraping relationship with said surface, said scraper bar assemblies being carried on one or more chains and extending transversely of the chain or chains and being spaced longitudinally thereon, and wherein each scraper bar assembly of the type described has a scraper bar with a recess formed therein to receive a link of a length of continuous chain to which the scraper bar is to be secured and a clamping block and fastener means to clamp said link in said recess to secure the scraper bar rigidly to said link, the arrangement being such that the scraper bar and the clamping block provide a substantially continuous scraping face when the clamping block is in clamping position.

The invention is particularly, but not exclusively, concerned with scraper bar assemblies of the type described, for use in scraper bar chain conveyors of the kind specified and of the centre strand type i.e., wherein the recess to receive the chain or chains is substantially central of each scraper bar assembly and the chain or chains is or are intended to run along the centre of a trough along which in use, the scraper bar assemblies pass.

Hitherto, the clamping block has been bolted to the bar by bolts which are received in passages in the scraper bar which extend normal to the scraping face of the bar.

Due to the recess, such bars are inherently weak in the region of the clamping block and the passages in this region which receive the bolts weaken the bar still further. In our previous Patent No. 1,362,552, it is sought to overcome this weakness by providing on each side of the bar a strengthening part which, over the longitudinal region of the bar in which the recess is formed, projects transversely outwardly relative to the adjacent and longitudinal region of the bar in which the recess is not formed.

It is an object of the invention to provide an improved scraper bar assembly of the type described in which the above described weakness is overcome or reduced.

According to a first aspect of the invention, we provide a scraper bar assembly of the type described wherein the scraper bar has an abutment surface which extends parallel or substantially parallel to the scraping face and the fastener means comprises an elongate coupling member adapted to be in abutting relationship with said abutment surface and to engage a retaining formation of the clamping block whereby in use, the clamping block is engaged in aaid recess in clamping relationship with said link.

Thus, whereas, previous scraper bar assemblies of the type described having passages for bolts extending normal to the scraping face have the above mentioned problem of weakness of the bar due to the passages, in the present invention this problem is overcome as there are no such passages provided in the bar. Of course, the weakness due to the recess remains, and if still greater strength is required, strengthening parts in accordance with our previous Patent No.

1,362,552 may be provided.

The abutment surface and the retaining formation may comprise passages formed in the scraper bar and clamping block respectively. The passages may be circular in cross section and are preferably cylindrical.

The bar in the region adjacent to the recess may be provided with bifurcated parts between the limbs of which, tongue parts of the clamping block may be received, the limbs and the clamping block having aligned passages which are adapted to receive the elongate coupling member.

The recess may be provided with a pair of parallel grooves each having a surface of generally part cylindrical configuration, said grooves being adapted to receive and locate a link of the chain.

The leading and trailing edges of the scraper bar may be formed with recesses in which the end portions of the links of the chain adjacent to said link to which the scraper bar is secured are accommodated.

Shallow rebates may be formed in the grooves and/or the clamping block to accommodate any irregularity of the chain such as a weld formed on the link of the chain.

The scraper bar may have side parts which slide on the conveyor surface, the side parts having edges formed with notches to facilitate the removal of debris from the surface as the bar slides.

According to a second aspect of the invention we provide a scraper bar chain conveyor of the kind specified having at least one scraper bar assembly according to the first aspect of the invention.

The invention is particularly useful in conveyors of the kind specified of the centre strand type.

According to a third aspect of the invention, we provide a method of making a scraper bar assembly according to the first aspect of the invention, comprising the steps of placing a member of substantially similar cross-sectional configuration but of slightly smaller dimension than a link of a chain to which the scraper bar assembly is to be attached in use, in the recess of the scraper bar, placing said clamping block over the member to hold the member captive, and temporarily attaching the clamping block to the scraper bar, and forming the abutment surfaces and retaining formations in the scraper bar and clamping block whilst they are temporarily attached.

By forming the abutment surfaces and retaining formations in this way, when the link of a chain is placed in the recess and the clamping blockis placed over the link, it is necessary to push the clamping block into tight engagement with the link to engage each of the elongate coupling members with the abutment surfaces and retaining formations. Consequently the link will be clamped very tightly.

Further, should the link be as small as the maximum tolerance of the chain permits, it will still be firmly clamped by the clamping block.

The invention will now be described in more detail with reference to the accompanying drawings in which: Figure 1 shows a fragmentary underneath plan view of a scraper bar chain conveyor having a scraper bar assembly embodying the invention with the conveyor trough shown in ghost outline with part of the chain cut away and the clamping block omitted for clarity; Figure 2 shows a fragmentary underneath plan view of a central portion of the scraper bar assembly of the conveyor of Figure 1 with a clamping block holding a link of chain captive; Figure 3 is a section along the line 3-3 of Figure 2, and Figure 4 shows an underneath plan view of a modified scraper bar embodying the invention.

Referring to Figure 1 of the drawings, there is shown a scraper bar chain conveyor comprising a trough 7 having a horizontal plane base part providing a conveyor surface 8 and upstanding sigma section side walls 9. A plurality of scraper bar assemblies 10 are moved along the trough 7 by a continuous chain 1 5.

Each scraper bar assembly 10 comprises a scraper bar 1 Oa having a scraping face 28 engaged with the surface 8 and an enlarged central chain engaging portion 12.

In Figure 1, the central portion 12 is shown with a link 14 of the chain 15 engaged in a pair of longitudinally spaced parallel grooves 13 formed in a recess 11, with part of the chain link 14 cut away. The central portion 12 has curved surfaces 1 6 (Figure 2) which abut and receive further links 17 of the chain 15.

Bifurcated parts 18 are provided on the central portion 12, the parts 18 having limbs 1 9 with aligned passages 20 formed therein extending parallel to the scraping face 28. An upper part of the walls of the passages 20 provide an abutment surface for engagement by a coupling member as hereinafter to be described.

Referring to Figures 2 and 3, a clamping block 21 is shown having tongue parts 21 a received between the limbs 1 9 of the bifurcated parts 18, to hold the link 14 of the chain 1 5 captive, the clamping block 21 having a retaining formation formed at each end. The formations comprising passages 22 in the tongue parts which extend parallel to the scraping surface 28 and are in alignemt with the passages 20 in the limbs 1 9 of the bifurcated parts 1 8 to receive elongate coupling members in the form of locking pins 23.

The links of a chain are usually formed by joining together two ends of a single piece of metal by welding and thus often where it has been welded, the link has a slightly raised portion such as shown at 25 in Figure 1 of the drawings.

The central portion 12 of the scraper bar 1 Oa and the clamping block 21 are formed with shallow rebates 26 to accommodate the raised portions 25.

Previously, clamping blocks have been attached to scraper bars by passing bolts through the clamping block into passages in the scraper bar which extend normal to the scraping face and are provided in the region of the recess. In use, this region is highly stressed and thus the recess and the passages considerably weaken the bar.

In the present invention however, the problem due to the passages is overcome as the locking pins 23 are received in passages 20 in bifurcated members 1 8 which are formed of additional material of the scraper bar.

Although the recess 11 weakens the bar in the region 24 at the side of the central portion 12, the central portion is enlarged to give extra strength in these regions.

The end edges 30 of the scraper bar 1 Oa are provided with notches 31 to facilitate the removal of debris which has become deposited on the outwardly facing sliding surfaces of the trough.

The clamping block 21 and grooves 13 are so dimensioned that the link 14 of the chain 1 5 is rigidly clamped in the grooves 1 3.

The passages 20 in the limbs of the bifurcated members and the passages 22 in the ends of the clamping block 21, are preferably formed in the following manner to ensure that the link 14 is clamped rigidly.

A member of substantially the same configuration as the link 14 of the chain 1 5 but of slightly smaller cross-sectional dimension, is placed in the grooves 13 of the scraper bar 1 Oa.

A clamping block 21 is then clamped in position over the member thus holding it captive.

The passages 20 and 22 are then drilled each in turn.

Thus when a link 14 of the chain 15 is placed in the grooves 13, the clamping block 21 will need to be firmly pushed into engagement with the link to align the passages 20 and 22 to allow the locking pins 23 to be located in the passages.

Therefore the link 14 will be clamped tightly even if it is as small as the maximum tolerance of the chain permits.

Thus the upper parts of the walls of the passages 20 provide an abutment surface for the coupling member. Preferably the passages 20 and 22 are drilled such that the clamping block 21 can only be received in one position i.e. it is not reversible.

Referring now to Figure 4 of the drawings, there is shown a scraper bar assembly 32 similar to that shown at 10 in Figures 1 to 3 but in which the central portion 35 of the scraper bar 32a engages and holds captive links 38 of two spaced parallel chains 36 and 37. The links 38 are each received in one of two pairs of spaced parallel grooves 40 and 41 and are held captive by a clamping block (not shown).

Again, shallow rebates 44 and 45 are formed to accommodate raised parts 46 of the links 38 and similar rebates are provided in the clamping block Bifurcated parts 47 are provided to receive the ends of the clamping block, and the limbs 48 of the bifurcated parts 47 have apertures 49 and 50 to receive locking pins (not shown). The apertures 49 and 50 are formed by a similar method as described with references to Figures 1 to 3.

Small other respects, the scraper bar assembly 32 shown in Figure 4 is identical to that shown at 10 in Figures 1 to 3.

Although the means of attaching the clamping block to the scraper bar has been described in each embodiment as being locking pins which are received in aligned passages in the clamping block and the scraper bar, it will be appreciated that the clamping block may be fixed to the bar by any other means in which a coupling member extends parallel or substantially parallel to the scraping face of the bar.

For example, the coupling means may comprise split pins, or bolts, part or all of the aligned passages being formed with an internal thread to receive the bolts.

The clamping block need not be formed with passages in each end, but may be formed with a recess of corresponding configuration to a locking pin.

The locking pin will engage the recess when it is located in the passages in the bifurcated part, thus clamping the block to the bar. The block will be constrained from movement in a direction parallel to the chain by the limbs of the bifurcated parts.

Although in both embodiments described above it is essential that the abutment surface of the bar and the elongate coupling member extend parallel or substantially parallel to the scraping face, it will be appreciated that the retaining formation of the clamping block need not extend parallel to the scraping face.

For example, the coupling member may be attached to an element, such as a bolt retained in a passage in the clamping block which extends normal to the scraping surface of the bar.

Claims

1. A scraper bar assembly of the type described wherein the scraper bar has an abutment surface which extends parallel or substantially parallel to the scraping face and the fastening means comprises an elongate coupling member adapted to be in abutting relationship with said abutment surface and engage a retaining formation of the clamping block whereby the clamping block is engaged in said recess in clamping relationship with said link.

2. A scraper bar assembly according to Claim 1 wherein the abutment surface and the retaining formation comprise passages formed in the scraper bar and clamping block respectively.

3. A scraper bar assembly according to Claim 2 wherein the passages are circular in crosssection.

4. A scraper bar assembly according to any one of the preceding claims wherein the bar, in the region adjacent to the recess, is provided with bifurcated parts between the limbs of which, tongue parts of the clamping block are received, the limbs and the clamping block having aligned passages which are adapted to receive the elongate coupling member.

5. A scraper bar assembly according to any one of the preceding claims wherein the recess is provided with a pair of parallel grooves each having a surface of generally part cylindrical configuration, said grooves being adapted to receive and locate a link of the chain.

6. A scraper bar assembly according to any one of the preceding claims wherein the leading and trailing edges of the scraper bar are formed with recesses in which the end portions of the links of the chain adjacent to said link to which the scraper bar is secured are accommodated.

7. A scraper bar assembly according to Claim 5 or Claim 6 where dependent on Claim 5, wherein shallow rebates are formed in the grooves and/or the clamping block to accommodate any irregularity of the chains such as a weld formed on the link of the chain.

8. A scraper bar assembly according to any one of the preceding claims wherein the scraper bar has side parts which slide on the surface of the conveyor, the side parts having edges formed with notches to facilitate the removal of debris from the surface as the bar slides,

9. A scraper bar assembly substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

1 0. A scraper bar assembly substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.

11. A scraper bar chain conveyor of the kind specified having at least one scraper bar assembly according to any one of the preceding claims.

12. A conveyor according to Claim 11 which is of the centre strand type.

13. A conveyor substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

14. A conveyor substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.

1 5. A method of making a scraper bar assembly according to any one of claims 1 to 11 including the steps of placing a member of substantially smaller dimension than a link of a chain to which the scraper bar assembly is to be attached in use, in the recess of the scraper bar, placing said clamping block over the member to hold the member captive, and temporarily attaching the clamping block to the scraper bar, and forming the abutment surfaces and retaining formations in the scraper bar and clamping block whilst they are temporarily attached.

16. A method of making a scraper bar assembly substantially as herein described with reference to Figures 1 to 3 of the accompanying drawings. ~~~~~~~~~~~~~~~

17. A method of making a scraper bar assembly substantially as herein described with reference to Figure 4 of the accompanying drawings.