US3427801A - Cast chains - Google Patents

Description

Feb. 18, 1969 c. D. MCLEISH 3,427,801

CAST CHAINS Filed Aug. 11, 1964 32 INVE/V r00. Car p. yfzcow @MgW ATTORNEY.

United States Patent 3,427,801 CAST 'CHAINS Charles D. McLeish, Waterloo, Ontario, Canada, assignor to Indiana General Corporation, Chicago, Ill. Filed Aug. 11, 1964, Ser. No. 388,834 U.S. Cl. 59-1 Int. Cl. B21] 17/00; B2211 25/02 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to cast metal chains and more particularly to a novel chain and the method or process of making same.

In the industry of making cement, lime and similar related products, large rotating kilns are used through which the material flows under relatively high temperatures. In order to keep the material moving, to break up clumps, to keep the material agitated and to transfer heat to the material the inside of the kiln is laced with lengths of chain which hang down from the upper part of the kiln and stack up on the lower sides and bottom of the kiln. As the kiln rotates the links of the chains constantly bump against each other and agitate the material and during part of the rotation cycle absorb heat and during the remainder of the cycle transfer heat. The agitation causes the links of the chains to be subjected to extreme wear. This is caused by the constant abrading action of one link against another, of the links against the sides of the kiln and of the presence of the material being treated which, being powdery in nature, is abrasive to the constantly moving chains.

In the past the links of the kiln chains have generally been made of wrought alloys including stainless steel and carbon steels. Even with these expensive alloys and steels the replacement rate of chain links is fantastic. The links wear both on the inside and outside and erode from the effects of the constant high temperature so that they have to be replaced frequently. The kiln must be taken out of service, cooled down and the chains replaced at great expense.

It is therefore a principal object of this invention to provide an improved chain for use in kilns that will have higher resistance to wear and better temperature characteristics.

It is another object of this invention to provide an improved method of making kiln chain links that will produce links for kiln chains of unusual creep strength.

It is still another object of this invention to provide an improved method of making kiln chain by casting and welding using a different basic material whereby better chains are produced at a cheaper cost.

And yet another object of this invention is to provide a novel method of casting the chain links thereby facilitating assembly of the chains for use.

These and other novel features of the invention will be best understood from the following description when taken together with the accompanying drawings, in which certain embodiments of the invention are disclosed, and in which the separate parts are designated by suitable reference characters in each of the views, and in which:

FIGURE 1 is a plan view illustrating a pattern plate for casting links for my improved kiln chain;

lot:

FIGURE 2 is a plan view of several links of chain such as cast in the pattern of FIGURE 1 in partially assembled relationship;

FIGURE 3 is a view of several links assembled in a ig with one link in position ready for welding;

FIGURE 4 is a cross-sectional view taken on the line 4-4 of FIGURE 2 illustrating one of several advantageous cross-sections for kiln chains.

My invention deals generally with the casting of solid links and split links which can then be joined together in such a way as to produce a chain of improved wear and heat resistant characteristics.

In order to simplify illustration of the invention, somewhat schematic views are employed showing in the least amount of detail the essential features to be included within my invention.

Referring to the drawings wherein similar reference numerals refer to similar parts throughout the several views, 10 represents the lower half of a pattern plate or die box which is adapted to have sand or the like 12 tamped therein with the imprint of a pattern 14 embedded into the sand in the form of two solid links or rings 16 and 18 and two split links or rings 20 and 22 all connected by sprews 24 to a gate 26. An upper half 28 of the pattern plate contains a mirror image of the imprint of a pattern 14 such that when the upper half 28 is placed over the lower half 10 a completed mold is formed ready for casting. It is to be understood that the mold can be made in many different and other well known ways such as by shell molding, and the like.

Casting alloys are then poured into the mold in the usual manner whereupon a casting resembling the impression of the pattern 14 of FIGURE 1 is produced. The sprews and risers are knocked off the links 16, 18, 20 and 22 whereupon said links are cleaned and otherwise prepared for assembling. Two of the solid rings or links 16 and 18 are assemble-d with one split link 20 (or 22) by passing the solid rings through the opening 30 in the split link 20. The split link 20 is then placed in a jig 34 which has a pair of reciprocally spaced jaws 36 and 38. The jaws 36 and 38 are aligned with diametrically opposite sides of the split link 20 with the opening 30 somewhat centrally spaced between the jaws.

The jig is activated and the jaws force the sides of the split link together until the opening 30' is closed. A welding step is then preformed on the ends of the link forming the opening 30 whereupon the split link 20 is welded at 32 into a solid link. The procedure is repeated many times to produce a kiln chain.

The newly formed chain being of alloy cast material is much more resistant to wear and heat and especially to the abrasive type wear occasioned by the constant rubbing and banging of the chains one against the other with the interposed material being processed in the kiln.

Chains made out of wrought or rolled stock are not sufficiently wear resistant to stand the heat and wear created during long and constant use in a kiln.

Cast alloys have high creep strength which is not only necessary but also is essential to successful use of chains for kilns. Creep strength is defined as the constant nominal stress that will cause a specific quantity of strain or creep rate at constant temperature in a given time. By modifications of compositions superior creep strength can be given to casting alloys over wrought alloys.

The cast links of my chain can be made in various cross-section configurations, to give maximum heat radiation surface area with minimum of weight, thus reducing fuel costs and keeping the weight economical. The shape of the links insures greater chain flexibility, reduces chain knotting, increases the scraping action in the kiln and is self-cleaning and prevents the formation of mud clumps.

In FIGURE 4 one cross-section that has been found to be very useful and has contributed to an improved chain is illustrated. The cross-section is essentially a figure 8 such that a greater surface area is exposed in such a way as to improve particularly the heat transfer characteristics. The greater heat transfer of the chains the more efficient the kiln operation, all of which is true with my improved cast chains.

The greater wear resistance of the cast alloy chains effects many savings. The initial chains are cheaper to produce, and since they last longer they save replacement costs and reduce downtime for the kiln. Each time a kiln is taken out of service to repair or replace kiln chains it necessitates flushing the kiln, cooling it down, working on the chains and then refiring and reheating before it is returned to service, all of which takes time and money.

By the improved chain and method of making same, it is possible to produce a better kiln chain, cheaper and more efficiently.

Having thus described my invention, what I claim is:

1. A method of forming a chain which comprises casting closed rings and open rings from an alloy, said alloy being of a composition having substantial creep strength and high wear resistance, assembling two closed rings with each open ring by inserting the open end of the open ring into the centers of the closed rings, forcing the ends of the open ring together and welding said ends together to form another closed ring joining the two cast closed rings.

2. A chain for use in rotating kilns comprising a pair of closed rings, an open ring joining said closed rings and having means for permanently closing the opening in said open ring, all of said rings being formed by casting an alloy into said rings, and said alloy having high creep strength and high wear and heat resistant characteristics.

3. A chain for use in a rotating kiln comprising a plurality of links connected together and having every other link a solid closed link joined by an open link which has been permanently welded closed, all of said links being formed by means of casting of an alloy said alloy having high creep strength and high wear resistant characteristics, and each link having a cross-sectional shape such as to provide a relatively large exposed surface area so as to improve the heat transfer characteristics of said chain.

4. A process of making a chain comprising the steps of preparing a mold, having open links and closed links, pouring into said mold a casting alloy having substantial creep strength and high heat and wear resistance characteristics, assembling an open link between every pair of closed links, welding the opening shut in each open link whereby a cast chain is formed for use in a kiln or the like.

References Cited UNITED STATES PATENTS 354,732 12/1886 Penman 249-57 1,670,758 5/1928 Witherow 59-35 2,820,874 1/1958 Dunn 59-31 3,015,716 1/1962 Pelkey 24957 3,135,504 6/1964 Chisler 263-33 3,176,3 7 4/1965 Nelson 249-57 CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

US. Cl. X.R.

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