AU646366B2

AU646366B2 - Chain link construction

Info

Publication number: AU646366B2
Application number: AU38364/93A
Authority: AU
Inventors: Glen John Ogden
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-06-04
Filing date: 1993-04-30
Publication date: 1994-02-17
Anticipated expiration: 2013-04-30
Also published as: AU3836493A; ZA936793B

Description

I 646366 P/00/009 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ,r C cr t, cc It r t c r cc c Name of Applicant: Actual Inventor: Address for Service: Invention Title: Details of Associated Provisional Applications: GLEN JOHN OGDEN GLEN JOHN OGDEN

AHEARNS

Patent Trade Mark Attorneys National Bank House 255 Adelaide Street BRISBANE QLD 4000 (GPO Box 185, Brisbane, 4001) "CHAIN LINK CONSTRUCTION" No. PL2784, filed 4 June 1992 No. PL4153, filed 17 August 1992 The following statement is a full description of this invention, including the best method of performing it known to me: i I s i 2 THIS INVENTION relates to chain link construction, and it particularly relates to heavy duty metal chain links, being directed to such links having sacrificial inserts for the purpose of improving the life expectancy of the chain links.

S 5 Considerable use is currently made in the mining industry of heavy chain for linear movement of heavy objects e uch as dragline buckets where the operating conditions preclude the use of wire rope. The severity of the operating conditions ultimately leads to wear in each inner end or crutch of the j1O chain link. It is generally considered not practical to S, lubricate the chain to reduce this wear condition. In S consequence, considerable time is lost and expense incurred through the need to repair the chain by labour intensive metal arc welding processes.

My present invention has been devised to overcome the disadvantages currently experienced with chain links becoming worn, and it has for its principal object the provision of a novel form of chain link as well as a novel method of and means for providing a fitted insert of metal of extreme hardness which may be readily replaced when necessary, obviating the requirement of repairing the chain by the arc welding processes as aforementioned.

Another object of the invention is to provide such a sacrificial insert and fitting method whereby its location and securement into the area of severe wear may be accomplished without undue difficulty or cost. Other objects and advantages of the invention will be hereinafter apparent.

With the foregoing and other objects in view, nry i invention resides broadly in a metal chain link of the type having spaced parallel side arms interconnected by integral looped end arms the inner surfaces of which coact with looped end arms of adjacent links to be subject to frictional wear, the longitudinal medial line of the link midway between the parallel side arms extending between the respective end extremities of the link at the respective looped end arms, characterised in that the inner surface of each looped end arm of the link is formed with a major recess extending from one 0 side of said medial line of the link to the other and acting to reduce the thickness of the end arm at the respective end extremity of the link, and there is provided a sacrificial metal link insert of substantially greater hardness fitted in said major recess and retained therein, the insert being thicker where it fits the reduced thickness of the end arm and being curved on its inner surface to approximate the customary surface which it replaces.

Suitably the insert may be retained in the major recess at least partly by registering weld locations on the insert S and the link body. Also, or alternatively, the major recess may have one or more tapered projections or recesses to coact in cam-like manner with corresponding recesses or projections on the metal link insert when the latter is moved longitudinally into place, thus preventing relative lateral movement.

Preferably the sacrificial insert has two substantially semicircular surfaces arranged as outer and inner surfaces respectively, the outer one fitting closely within the 4 similarly shaped major recess and the inner one providing the frictional engagement surface for the link end. It is also preferred that the outer surface of the insert be grooved or recessed peripherally to receive a locating ridge or lug of the looped end arm. Other features of the invention will be noted from the descriptions of the preferred embodiments which are given by way of example only.

In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, whereintt Fig. 1 shows in plan view an assembly according to my invention in which each end of a chain link is fitted with a sacrificial insert; Fig. 2 is a side elevation of the assembly shown in I 15: IFig. 1; C. t Fig. 3 is an end elevation of the assembly shown in Figs. 1 and :2; c. IFigs. 4 and 5 are sectional views on the lines 4-4 and 5-5 respectively in Fig. 1; t 21CJ: Fig. 6 is an exploded isometric view of one end of the chain link and showing the sacrificial insert in separated relationship, and Fig. 7 is similar to Fig. 6 but showing a slightly modified form of chain link.

The assembly shown in the drawings comprises a chain link shaped at each end to accommodate a fitted sacrificial insert 11. The link 10 has a pair of spaced elongated side arms 12 in parallel relationship and interconnected in closed i Ia form by integral looped end arms 13 which are provided at their inner surfaces 14 each with a major recess 15 which extends to each side of the medial longitudinal line of the link at its major axis, so that the end arm 13 is of reduced thickness at the end extremity 16 on the said major axis.

However, as shown in Fig. 6, the end extremity 16 of the end arm 13 is more recessed at top and bottom in the illustrated disposition, separated by a locating ridge or lug 17 extending peripherally around the inner face of the arm 13 and indicated b in dotted outline in the assembled plan view of Fig. 1.

t .Each sacrificial insert 11 is adapted to be fitted into Sand retained within the respective major recess 15 and has its thickest portion 18 where it fits the reduced thickness at the end extremity 16 of the link, the insert being curved on its l inner surface 19 to approximate the customary chain link surface which it replaces. The inner surface 19 is substantially semicircular, as also is the outer surface which fits within the respective major recess, while the outer surface 20 is also grooved or recessed peripherally as indicated at 21 in the drawings to receive the locating ridge or lug 17 of the looped end arm 13. The two semicircular surfaces 19 and 20 have their centres of curvature at spaced positions along the medial line. At each side of the insert 11, there are three weld recesses 22 as illustrated to register with recesses 23 similarly placed around the end arms 13 for the welding together of the assembled parts for further prevention of the detachment.

The chain link 10 may have longer or shorter parallel

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6 side arms 12 and other design details as required or customary, including the form having opposite end openings separated by a transverse dividing bar (not shown). It will be noted that the chain links have the same general appearance as conventional links and may be made in the usual range of sizes, including 400kg for example. Also the usual internal length of opening or openings will be retained. Current chain links tend to wear out in a set period of time regardless of size, under severe wear conditions, and the present invention allows for the use of throw-away wear-resistant inserts which are heat treated to desired super hardness. It will be appreciated that the same treatment cannot be given to the Snormal links because they become more and more brittle.

Whereas current links are thus made with a compromise hardness factor of say 410B, in my new links I envisage the use of softer metal, such as 360B.

Each link 10 is made to appropriate shape to accommodate c and retain the insert 11 at each end, being cast with appropriate openings at one end, bearing in mind that in 2 o normal chains every second link must in any event be cut to allow hinged engagement with the next. Standard compositions may be used in casting, notably high grade steel alloys, while suitably a 100 ton press (for example) may be used to crush fit each insert in the link recess, the link being softer and thus suitably tending to open up for that purpose. i In fitting the replaceable crutch or insert at each end of the link, it will be noted that the locating lug 17 in the central recess or groove 21 ensures rigidity against movement

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in all directions other than towards the opposite end, while the weld recesses 22 and 23 in the respective parts constitute mating apertures to receive and retain welding material without undesirable protrusion, each having a ccmbined dimension of 0.75 inch or 1.00 inch for example.

To supplement the effectiveness of the welds in recesses 23 and 23, or in order to avoid the need for welds I may prefer to provide at each side of each end arm 13 at each end of the link a tapered integral ridge or projection 24 as shown in Fig. 7 where there is also shown a tapered groove 25 at .*each side of the medial longitudinal line of the insert 11, the grooves 25 acting to receive the projections 24 in a sliding cam-like action with locking resulting from the tapered configurations. The grooves 25 are at corresponding "T positions lengthwise of the link and insert and at equal 9r99 distances on each side of the centre line. While the projections 24 could be replaced by grooves to accommodate projections on the inserts, it is preferable to have the projections on the chain link so as not to reduce strength and 2b also for ease of manufacture since the grooves 25 are provided without difficulty at the positions shown in Fig. 7 on the insert 11.

It will be noted that the illustrated link will achieve the desired results without having any undue bulk or appearing different from normal links, but of course greater thickness of material may be used where desired, the back being suitably strengthened in that manner if and where it is thought appropriate to do so. The embodiments shown and described has Ei 8 been given by way of illustrative example only and may be subject to many modifications of constructional detail and design as will be readily apparent to persons skilled in the art, without departing from the broad scope and ambit of the invention as defined by the appended claims.

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Claims

1. A metal chain link of the type having spaced parallel side arms interconnected by integral looped end arms the inner surfaces of which coact with looped end arms of adjacent links to be subject to frictional wear, the longitudinal medial line of the link midway between the parallel side arms extending between the respective end extremities of the link at the respective looped end arms, characterised in that the inner surface of each looped end arm of the link is formed with a major recess extending from one side of said medial line of the link to the other and acting to reduce tbe *i thickness of the end arm at the respective end extremity of the link, and there is provided a sacrificial metal link insert of substantially greater hardness fitted in said major recess and retained therein, the insert being thicker where it fits the reduced thickness of the end arm and being curved on t i its inner surface to approximate the customary surface which it replaces.

2. A metal chain link according to Claim 1, and further characterised in that each insert is retained in its respective major recess at least partly by registering weld locations on the insert and the link body.

3. A metal chain link according to either of Claims 1 or 2, and further characterised in that each major recess is provided with one or more tapered projections or recesses to coact in cam-' ike manner with corresponding recesses or projections on the metal link insert when the latter is moved longitudinally into place, thereby preventing relative lateral movement. i i P B i 'I i ill a i

4. A metal chain link according to Claim 3, and further characterised in that the tapered projections are provided on the end arms and the tapered grooves are provided on the inserts, said projections and grooves extending in the direction lengthwise of the chain link. A metal cha,. link according to any one of the preceding claims, and further characterised in that each insert has two substantially semicircular surfaces arranged as outer and inner surfaces respectively, the outer one fitting closely within the similarly shaped major recess, and the inner one providing the frictional engagement surface for the link end.

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6. A metal chain link according to claim 5, and further characterised in that the substantially semicircuilar surfaces of each insert have their centres of curvature disposed on the S medial longitudinal line of the link and spaced from one another when the insert is in place.

7. A metal chain link according to any one of the preceding claims, and further characterised in that the outer surface of each insert is grooved or recessed peripherally to receive a0 corresponding locating ridge or lug of the respective looped end arm.

8. A metal chain link according to any one of the preceding claims, and further characterised in that the thickness of each insert in the direction at right angles to the plane through the side arms is equal to the maximum thickness of the chain link body remote from each insert.

9. A method of making a metal chain link of the type having spaced parallel side arms interconnected by integral looped L 1 spaced parallel side arms interconnected by integral looped end arms the inner surfaces of which coact with looped end arms of adjacent links to be subject to frictional wear, the longitudinal medial line of the link midway between the parallel side arms extending between the respective end extremities of the link at the respective looped end arms, said method comprising the steps of forming a major recess in '.he inner surface of each looped end arm and inserting therein a sacrificial metal link insert of substantially greater hardness, the insert being replaceable after a period of wear.

10. A metal chain link substantially as hereinbefore described with reference to the accompanying drawings. Dated this 29th day of October, 1993. GLEN JOHN OGDEN t| By his Patent Attorneys SAHEARNS I t >s T Lj J o; \QSS ,A 1 ABSTRACT The invention provides a metal chain link (10) of the type having spaced parallel side arms (12) interconnected by integral looped end arms (13) the inner surfaces of which coact with looped end arms of adjacent links to be subject to frictional wear, the longitudinal medial line of the link midway between the parallel side arms (12) extending between the respective end extremities (16) of the link (10) at the respective looped end arms characterised in that the inner surface (14) of each looped end arm (13) of the link is formed with a major recess (15) extending from one side of said medial line of the link to the other and acting to reduce the thickness of the end arm (13) at the respective S end extremity (16) of the link, and there is provided a S sacrificial metal link insert (11) of substantially greater hardness fitted in said major recess (15) and retained therein, the insert (11) being thicker where it fits the reduced thickness of the end arm (13) and being curved on its inner surface (19) to approximate the customary surface which it replaces. Si t: