GB2154686A

GB2154686A - Hook or shackle assemblies for chain slings

Info

Publication number: GB2154686A
Application number: GB08503147A
Authority: GB
Inventors: Victor Toubi
Original assignee: LIFTING GEAR PRODUCTS
Current assignee: LIFTING GEAR PRODUCTS
Priority date: 1984-02-20
Filing date: 1985-02-07
Publication date: 1985-09-11
Also published as: GB8404370D0; GB8503147D0

Abstract

A load pin 16 is held captive in aligned bores 18 in the forked end of the hook or shackle by fitting a dished retaining disc 22 within one of the bores 18 against an end of the load pin 16 and inwardly deforming it by means of a hammer and punch to bring it to a flat condition whereby its edge is caused to enter an undercut groove 20 in the bore 18. The central hole 24 in the load pin 16 allows the retaining disc to be punched into it to release the load pin 16. <IMAGE>

Description

SPECIFICATION Hook or shackle assemblies for chain slings and the like The invention relates to hook or shackle assemblies for chain slings and the like.

Items of load lifting apparatus frequently employ lengths of chain from which the load is to be suspended, the ends of the lengths of chain usually being provided with either a hook or with a shackle assembly. Load lifting hooks, and shackles if they are to be perma nently connected to the length of chain concerned rather than readily removable, are usually connected to the chain by respective load pins which for reasons of safety are no longer than the overall widths of the forked ends of the hooks or shackles concerned. The object of the invention is to provide a method of fixing such a load pin in position which will be both safe and of a neat appearance but will be relatively inexpensive.

According to the invention, there is provided a method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle, the method including the step of machining an undercut groove in one of the aligned bores, fitting the pin in the aligned bores and aligning an outer end surface of the pin with an inner side surface of the undercut groove, fitting a dished retaining disc in the end of the bore to abut the outer end surface of the pin, and inwardly deforming the disc so that in being brought to a flat or substantially flat condition its peripheral edge is caused to spread radially outwards into engagement with the undercut groove.

The step of fitting the pin in the aligned bores so that its outer end surface is aligned with the inner side surface of the undercut groove may be effected by causing the inner end surface of the pin to abut against an abutment surface within the bore in which that end of the pin is fitted. The method may include the forming of the outer end surface of the pin with a central hole or depression so that, if it should subsequently be required to remove the load pin from the load lifting hook or shackle, the retaining disc can be inwardly deformed to bring it back to a dished condition and to cause its peripheral edge to be drawn radially inwards and out of engagement with the undercut groove. The retaining disc may be made of any highly ductile material such as copper or copper alloy or aluminium.

However, the retaining disc could be made of mild steel, and in this case the method may include the further step of providing the periphery of the disc with a plurality of radial slits or crimps.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a chain sling embodying the invention, Figure 2 is a partly sectioned side view of the load pin and shackle assembly thereof, drawn to a much larger scale than Fig. 1, and Figure 3 is a view which will be referred to when describing a possible modification.

Referring now to Fig. 1 of the drawings, the chain sling there illustrated includes a length of chain 10, a load pin and hook assembly generally indicated 1 2 and a load pin and shackle assembly generally indicated 14.

In Fig. 2 there is illustrated the method by which the load pin 1 6 has been secured in the aligned bores 18, 18 in the forked end of the shackle. The method has involved the machining of an undercut groove 20 in one of the aligned bores 18, fitting the load pin in the aligned bores and aligning an outer end surface of the pin with an inner side surface of the undercut groove, fitting a dished retaining disc 22 in the end of the bore to abut the outer end surface of the pin, and inwardly deforming the disc so that in being brought to a flat or substantially flat condition its peripheral edge has been caused to spread radially outwards into engagement with the undercut groove. It will be observed that when drilling the aligned bores in the forked end of the shackle, the drill has not been allowed to fully break through.There has therefore been formed an abutment surface for the end of the load pin, this being at a position such that the outer end surface of the pin has been aligned with the inner side surface of the undercut groove when the load pin has been fully inserted in the aligned bores.

It has been found that the load pin has been very firmly and therefore safely secured in position by the method described. When the retaining disc has been hammered flat there is virtually no risk whatever of it ever dropping out by inadvertence. If it is observed that the disc is substantially flat this can be taken as proof positive that the load pin has been safely located in the assembly. It will be seen that that the appearance of the finished article is also very neat and pleasing. The cost of this method of assembly is also very low.

When it is desired to remove the load pin from the shackle this can very quickly and easily be effected. It will be seen that the outer end surface of the load pin has been formed with a central hole 24 (this being a good deal smaller in diameter than th'e load pin and relatively shallow, being less than half the effective bearing width of the pin in that part of the shackle, so that the strength of the assembly is not affected). Consequently, it will be understand that by the use of a hammer and punch the retaining disc can be inwardly deformed to bring it back to a dished condition and to cause its peripheral edge to be drawn radially inwards and out of engagement with the undercut groove. The load pin can then be extracted, pushing the deformed disc before it.

When securing the load pin in position it will be preferable to use a flat ended punch of the same diameter as the load pin to bring the retaining disc to the flat or substantially flat condition. In this way there will be no danger of the disc being inwardly deformed beyond the flat condition and the assembly thereby being rendered unsafe.

The retaining disc will preferably be made of any relatively ductile metal such as copper or copper alloy or of aluminium. In this case it may be in the region of 2 m.m. thick. The undercut groove 20 in which the retaining disc is to be engaged need be only fractionally wider than the thickness of the disc. The depth of the undercut groove may for example be between 1 m.m. and 2 m.m. The diameter of the retaining disc need be only of the same nominal diameter as the diameter of the undercut groove. However, it is not essential for the retaining disc to be made of a ductile metal as soft as copper or aluminium. For example, the disc could be made of a socalled deep drawing mild steel. In this case the disc will require to be made somewhat thinner and its outer periphery may be provided with radial slits or crimps 26 as shown in Fig. 3. It will of course be understood that in the chain sling illustrated by way of example in Fig. 1, the load pin in the hook assembly will have been secured in position in exactly the same manner as the load pin in the shackle assembly.

The invention can be used in connection with various other items, for example, socalled shortening clutches for shortening the effective lengths of chains, turnbuckle ends and connectors for lengths of chain.

Claims

1. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle, the method including the step of machining an undercut groove in one of the aligned bores, fitting the pin in the aligned bores and aligning an outer end surface of the pin with an inner side surface of the undercut groove, fitting a dished retaining disc in the end of the bore to abut the outer end surface of the pin, and inwardly deforming the disc so that in being brought to a flat or substantially flat condition its peripheral edge is caused to spread radially outwards into engagement with the undercut groove.

2. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle, in which the step of fitting the pin in the aligned bores so that its outer end surface is aligned with the inner side surface of the undercut groove is effected by causing the inner end surface of the pin to abut against an abutment surface within the bore in which that end of the pin is fitted.

3. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle according to either one of the preceding claims, including the forming of the outer end surface of the pin with a central hole or depression so that, if it should subsequently be required to remove the load pin from the load lifting hook or shackle, the retaining disc can be inwardly deformed to bring it back to a dished condition and to cause its peripheral edge to be drawn radially inwards and out of engagement with the undercut groove.

4. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle according to any one of the preceding claims, in which the retaining disc is made of a highly ductile material such as copper or copper alloy or aluminium.

5. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle according to any one of claims 1 to 3, in which the retaining disc is made of mild steel, including the further step of providing the periphery of the disc with a plurality of radial slits or crimps.

6. A load lifting hook or shackle assembly, in which the load pin has been secured in the aligned bores in the hook or shackle by the method claimed in any one of the preceding claims.

7. A method of securing a load pin in the aligned bores in the forked end of a load lifting hook or shackle, substantially as hereinbefore described with reference to the accompanying drawings.

8. A load lifting hook or shackle assembly, substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.