GB2183350A

GB2183350A - Device for checking overloading of chains

Info

Publication number: GB2183350A
Application number: GB08625674A
Authority: GB
Inventors: Volker Pilz; Anton Muller; Hermann Schinko
Original assignee: Eisen und Drahtwerk Erlau AG
Current assignee: Erlau AG
Priority date: 1985-10-26
Filing date: 1986-10-27
Publication date: 1987-06-03
Anticipated expiration: 2006-10-27
Also published as: DE8530361U1; DE3538118A1; GB8625674D0; BR8605172A; SE8604353D0; SE8604353L; IT1197885B; IT8622041A0; GB2183350B

Abstract

The device may be fitted to an uninterrupted chain and carries no tensile force in use. It comprises two connecting parts eg bolts 7, 8 which secure clamping members 9, 10, 11, 12 within two spaced chain links. An elongate guide plate 4 is secured at one end to clamping members 10 and 11 by bolt 8, but its other end is free to move longitudinally in a slot provided in clamping member 12. One end of another elongate plate 6 is rotatably mounted upon clamping members 10 and 11 by bolt 8 and bush 49. A further elongate plate 5 is rigidly but adjustably secured at one end by bolt 7 to clamping members 9 and 12. The other ends of plates 5 and 6 lie adjacent one another and are connected by a pin 41 housed therein. Excessive strain imposed upon the chain causes relative movement of plates 5 and 6 which disengages connecting pin 41, allowing plate 6 to rotate about bush 49. <IMAGE>

Description

SPECIFICATION Device for checking overloading of chains The invention relates to a device for checking for overloading of chains of the type comprising at least one connecting partwhich maybedetachablycon- nected to the chain and an indicator device which serves to indicate overloading of the chain.

In a known checking device ofthis type, the indicator is formed byan oval member, which hastwo cross-pieces projecting into the opening ofthe link at right angles to the longitudinal direction ofthe chain.

They form parts of the apparatus which face each other, whereof the end faces define a gap in the initial position of the checking device. The oval member is suspended by two insertion locks, which form the connecting members, in the ends ofthe interrupted chain. The chain member lies loosely in the insertion locks parallel with this checking device.

When the chain is overloaded, the oval member is deformed so that the cross-pieces move towards each other and the spacing between them is reduced. From this the competent safety engineer can re cognisethatthe chain is overloaded.

Such checking device has the drawback that as a result of its deformation the oval member can no lon ger be used fora furtherchecking operation and must be exchanged. Furthermore, the length of chain is interrupted by the oval member arranged between the ends of the chain. Expensive chain locks forconnecting the oval membertothe ends ofthe chain are required. This involves considerable manufacturing, assembly and storage costs.

It is the object ofthe invention to construct a check ing device suchthatwith simple indication ithasa simple construction without additional fittings and can be re-used after each measurement.

The invention provides a device for checking for overloading of chains, comprising at least one connecting part adapted to be detachably connected to the chain, and an indicator device operable to indicate the overloading of the chain, wherein the checking device is adapted to be fitted to the uninterrupted, continuous chain so that when the chain is under load, the flow of force passes exclusively through the chain links.

As a result of the construction according to the in ventionithe checking device does not receive any forces when the chain is loaded. Therefore, when the chain is overloaded, the checking device is not deformed and/or damaged. Dueto this there is no nec essity for the checking device according to the invention or parts ofthe deviceto be exchanged,when an overload situation has occurred. The checking device according to the invention may thus be re-used immediatelyforthe next checking operation.

Since the checking device according to the invention is attached to a taut continuous chain section, no expensive chain locks or the like are necessary for connecting the checking device to each end ofthe chain, due to which the manufacturing and assembly costs may be reduced. Moreover, in the case of an overload, the chain is not stressed in a jerky manner, since the checking device receives no forces and is not deformed, which could lead to sudden loading of the chain. On the contrarythefull force acts on the chain from the beginning.

Furtherfeatures ofthe invention will become apparent from the Claims, description and drawings.

The invention is described in detail hereafter with reference to an embodiment illustrated in the drawings, in which: Figure 1 shows a checking device according to the invention in longitudinal section, Figures2 and 3 are each views of the device according to Figure 1 in the direction of arrows II and Ill.

The checking device 1 according to Figures 1 to 3 servesforchecking for overloading of lashing or sling chains. Forth is purpose it is detachably connected to atautchain section 2 ofthe chain 3sothat the checking device does not absorb any forces when the chain 3 is loaded.

The checking device 1 comprises a guide part4 constructed as a cover plate, which is connected by way oftwo connecting parts 7 and 8 to two parts of the apparatus 5 and 6 likewise constructed as cover plates. The cover plates 5 and 6 lie parallel to the guide cover plate 4 and are arranged in alignment one behind the other. They are held by clamping members 9 to 12 at a distance from the guide cover plate 4, which clamping members are arranged on the connecting parts 7 and 8. The checking device 1 according to Figure 1 is connected by its cover plates 4and 6and the clamping members9to 12toform a unit surrounding the chain section 2 in the form of frame.The cover plates 4to 6 are arranged so that they are exposed in the longitudinal direction ofthe chain, whereas the connecting parts 7,8are inserted at right angles thereto through an end chain link 13, 14 of the chain section 2. The spacing ofthe guide cover plate 4from the cover plates 5,6 is slightly greaterthanthewidth ofthechain links 15to 17of the chain section 2 lying at right angles to the long itudinal central plane of the checking device 1.

The guide cover plate 4 extends over the entire length of the checking device 1. It is narrow and has a relatively long construction. In the embodiment, when the checking device 1 is mounted, it extends over more than 5 chain links 15 to 19 and partly over the end chain links 13, l4asfarasfurtheradjoining chain links 20,21. The width ofthe cover plates Sto 6 is less than the width ofthe chain links. At one end, namelythe upperend 22 in the assembled condition (Figure 3),the guide cover plate4comprises an opening 23, through which the end 25 of the connecting member 8 projects. It is constructed as a bolt with a bolt head 24. As shown in Figure 1, when the checking device 1 is mounted, this bolt head 24 bears against the outer side 26 ofthe guide cover plate 4.

The other, lower end ofthe cover plate 27 (Figure 3) comprises a central slot 28 which is open towards the end face 33. By its end 27, the guide cover plate4 is held in a torsion-free manner on the clamping part 12, which has a groove in which the end 27 ofthe cover plate is inserted. The sides 29,30 of the end 27 ofthe cover plate defining the slot 28 bearwith their outer sides againstthe walls of the groove. Tol- erances in the respective chain 3 may be compensa ted forbyway ofthis insertion connection, inthatthe end 27 of the cover plate is inserted to a greater or lesser extent in the groove depending on the size of the chain link.

The connecting part 7, which extends through a central through hole in the clamping member 12, extends in the region of the base 31 ofthe slot 28 (Figure 3) in the guide cover plate 4. The blockshaped clamping member 12 comprises a clamping section 1 2a lying between the cover plates 4 and 5 and a guide section 1 2b located on the outer side 26 ofthe guide cover plate 4.

The cover plates 5 and 6 (Fig u re 2) preferably have the same construction and are half as long as the guide cover plate 4. At its lower end 35 the lower cover plate 5 has an approximately rectangular recess36,which extends in the longitudinal direction ofthe cover plate and receives a head 66 of the connecting part 7. The narrow upper and lower edges 37 ofthe recess36 are rounded-offinthe shape of part ofacircle.

The other end 38 ofthe first cover plate 5 has rounded narrow edges 39,40 and in the flat front face 34a central insertion opening 39a which is open towards the end face, into which the lower half of a positioning part constructed as a bolt 41 projects. The bolt 41 is attached by its other half 42 in a second insertion opening 44a in the second cover plate 6 which opening is on the end face and is in alignment with the insertion opening 39a. Also, the narrow edges 45,46 ofthe end 44 ofthe cover plate are rounded in a corresponding manner, likethe edges 39,40 of the cover plateS. It is thus ensured that at the time of relative movements the cover plates 5,6 are not damaged or cannottiltorbecomejammed.

The cover plates 5 and 6 are ofthesame length and have the same width as the guide cover plate 4.

When the checking device 1 is mounted, the end faces 43 and 47 of the ends 38 and 44 of the cover plates bear against each other, in which case the bolt 41 is counter-sunk in the insertion openings 39a, 44a of the ends 38,44 ofthe cover plates.

At its upper end 48 the cover plate 5 comprises a through hole, in which a bearing bush49forthe cover plate 6 is located. It bears by an annularflange 50 against the outer side 51 of the cover plate (figures 1,2). The bearing bush 49 is seated on one end 52 of the connecting part 8, which projects by a threaded section beyond the annularflange 50. Screwed onto the threaded section is a nut 53, by which the ends 22,48 of the cover plates are braced with respect to each otherwith the interposition ofthe clamping members 10,11.

The clamping members 10,11 have the same construction and are arranged with mirror symmetry with respect to the longitudinal central plane ofthe checking device. They are in the form of a cuboid.

Their length is greater than the width of the cover plates 4to 6 and theirwidth is approximately equal to their height. The clamping members each com- prise a central transverse bore, which align with each other and through which the connecting part8isin- serted. The clamping member 10, 11 project overthe same width beyond the two longitudinal edges 54, 55 or 56,57 ofthe cover plate 4 or 5. (Figures 2,3).

On their facing sides, the clamping members 10, 11 are provided on the upper side and lower side re spectivelywith a concaveshoulder58to 51,against which the two chain links 17 and 21 connected to the end chain link 14 bearin an areal mannerbytheir curved sections.

The lower clamping member 9 and the clamping part 1 2a ofthe clamping member 12 are constructed to correspond to the guide members 10,11 and likewise have concave shoulders 62 to 65, against which the chain links 13 and 20 bearovertheirentiresurface by their curved sections. The connecting part 7 projectsthrough the aligned openings in the clam ping members 9 and 12, in which case it lies with its angular head 66 counter-sunk in the recess 36 in the cover plate 5. The head 66 is at a distance from the upperedge37oftherecess36,duetowhichtol- erances and differences in length ofthe chain links or individual chains can easily be compensated for.The head 66 bears by its surface parallel to the longitudinal central plane of the checking device 1 over its entire surface against the longitudinal edges 36a, 36b of the recess 36, which form guide surfaces for the cover plate 5.

On its outer side the head 66 comprises a circular end disk 67, which is supported by its projecting edge 68 (Figure 2) on the outer side of the cover plate 5a. The connecting part 7 is prevented from loosening by a nut 69 (figure 1 ),which is screwed to the free end 70 ofthe connecting member projecting outwards beyond the guide cover plate 4.

In the unloaded initial position ofthe checking device 1, with the assistance of the clamping members 9to 12 and the connecting parts 7 and 8, the cover plates 4to 6 are connected to form a unit on the loaded chain section 2. In this position the cover plates 5 and 6 are held together and guided in their aligned position bywayofthe bolt41. The coverplates 5,6 bear against each other by their end faces 43,47,so thatthe bolt41 is notvisible. Now ifthe chain 3 should be overloaded during its use, then it expands, but in which case there is not tensile stress on the checking device 1, so that it is not deformed and damaged.This is therefore based on the fact that when the chain 3 is overloaded, as a result oftheir loose connection the cover plates 5,6 are drawn away from each other in opposite directions and the guide cover plate 4 is drawn away from the clamping member 12, in which case the cover plate 4 with its sides 29,30 is guided on the associated walls ofthe groove in the clamping member 12. If chain 3 is excessively expanded, then the upper cover plate 6 is drawn upwards in the direction of arrow Pin Figure 1 or the cover plate 5 is drawn downwards. The bolt 41 attached to the cover plate 6 in this case slides to a greater or lesser extent out ofthe end opening 39a in the cover plateS, depending on the overload. Since the end faces 43,47 ofthe cover plates 5,6 are then at a distance apart, the bolt 41 is clearly visible. When the distance has reached the dimension A 1 (Figure 2), the overload has become inadmissibly high.

Then, since it is arranged to rotate on the bush 49, the cover plate 6 may rotate or swing out with respectto the bush, when it comes free from the other cover plate 5. It twists particularly easily if cover plate 6 is constructed to be asymmetrical with re spect to its weight. Then, even in so-called single strand chains, it may swing out easily after stretching and thus release the bolt41, so that it and thus also the stretching are easily recognisable. Duetothis,no measurements our special checking measures are necessary for the checking operation. After indica ting an overload ofthistype, each of the individual parts ofthe checking device 1 has its original shape, so that the checking device can be brought back into its initial position by simply swinging the cover plate 6 back into its aligned postion with respect to the cover plate 5 and by fitting the cover plates together, in which initial position it is ready for usefora new checking operation.

Claims

1. Adeviceforcheckingforoverloading of chains, comprising at least one connecting part adapted to be detachably connected to the chain, and an indicator device operable to indicate the overloading ofthe chain, wherein the checking device is adapted to be fitted to the uninterrupted, continuous chain sothatwhen the chain is under load, the flow of force passes exclusively through the chain links.

2. A device according to claim 1, having an opening in the longitudinal direction ofthe chain, and at least one part ofthe device is arranged to move relativeto another part of the device.

3. A device according to claim 2, wherein said one part ofthe device is arranged to tilt.

4. A device according to claim 2 or claim 3, wherein, in the initial position ofthe checking device, said parts of the device are held in the connection position by way of a positioning part.

5. A device according to claim 4, wherein the positioning part is a bolt, which projects into aligned openings on end faces of said parts of the device.

6. A device according to any one of claims 2 to 5, wherein said parts of the device are cover plates arranged one above the other in the longitudinal direction ofthechain.

7. A device according to any one of claims 2 to 6, wherein said other part of the device is held in anon- rotary manneron said at least one connecting part.

8. Adevice according to any one of claims 2to7, comprising a pluralityofconnecting parts, wherein said one part ofthe device is arranged on a bush, which is seated on another connecting part.

9. Adeviceaccordingto any oneofclaims2to7, comprising a plurality of connecting parts, wherein said connecting parts are bolts, which project through an opening in a chain link of a chain section.

10. A device according to claim 4, oranyclaim dependent thereon, wherein at its end remote from the positioning part, said other part ofthe device comprises a substantially rectangular recess with guide surfaces lying opposite each other and extending in the longitudinal directionofthechainfora head of said at least one connecting part.

11. Adeviceaccording to claim 10,whereinsaid head lies in the longitudinal direction ofthe chain with clearance in the recess in the other part ofthe device.

12. A device according to any one of claims 2 to 11,wherein the edges ofthe opening in the device extending at right angles to the longitudinal direction ofthe chain are rounded-off.

13. A device according to any one of claims 2to 12, wherein on theirfront sides which are in facing relationship, said parts ofthe device comprise rounded corners and edges.

14. Adeviceaccordingto anyoneofclaims2to 13, wherein a guide part is provided which is substantially parallel with and spaced from said parts of the device.

15. Adeviceaccordingto claim 14,whereinwhen the checking device is mounted on a chain, said guide part and said parts ofthe device lie on different sides of the chain.

16. A device according to claim 14 or claim 15, wherein the guide part is arranged to move long itudinally with respect to said other part of the device.

17. A device according to anyone of claims 14to 16, wherein at one end thereof, the guide partcomprises a slot open on an end face of said guide part, bywhich it is guided to move longitudinally on said at least one connecting part.

18. A device according to anyone of claims 14to 17, wherein with its other end the guide part is held to move longitudinally in a first clamping member.

19. Adeviceaccordingto claim 18whendepen- dent on claim 8, wherein the other connecting part projects th rough aligned openings in the bush and the other end of said guide part.

20. Adeviceaccordingto claim 19,whereinthe first clamping member is located on one connecting part.

21. A device according to claim 20,wherein a second clamping member is located on said one connecting part, which second clamping member is constructed in the same way as a clamping section of said first clamping member located between said guide partandsaid otherpartofthedevice.

22. Adevice according to claim 21,whereintwo adjacent third and fourth clamping members are likewise located on another connecting part.

23. A device according to claim 22, wherein the third and fourth clamping members are constructed substantially in the same way as the second clamping member.

24. A device according to claim 22 orclaim 23, wherein the adjacent clamping members are arranged with mirror symmetry.

25. A device according to anyone ofclaims 21 to 24, wherein at their opposing edges the clamping members have concave shoulders, against which adjacent chain links of a chain bearwiththeircurved sections when the chain is elongated.

26. A device according to any one of claims 21 to 25, wherein the clamping members extend approximately parallel with a longitudinal central plane of a checking device, and project laterally beyond said parts ofthe device and the guide part.

27. A device according to any one of claims 21 to 26, wherein the clamping members are braced bythe connecting parts with respect to associated chain links of a chain.

28. A device for checking for overloading of chains substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.