US2871535A - Permanent mold and method for making cast chain link - Google Patents

Description

Feb. 3, 1959. J. s. NELSON ,535

PERMANENT MOLD AND METHOD FOR MAKING CAST CHAIN LINK Filed Oct. 2, 1956 2 Sheets-Sheet 1 JOH/V s, NELSO/V BY Zum; /MM

. ATTORNEYS Feb. 3, 1959 J. S. NELSON PERMANENT MOLD AND METHOD FOR MAKING CAST CHAIN LINK Filed Oct. 2. 195:;`

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I 2 Sheets-Sheet 2 E slab/ish Mo/len Metal Provide Permanenf Ma/d l Pre/;ear Permanent Maid and Till /f la 45ang/e Pour/'n Mera! Without fizrbu/ence S/mu/taneausb' Hammer Me Bottom af Ma/d 'lmmed/aIe/y Open the Ma/d and Remove the Casting INVENTOR JOH/V 5, NELSON V ATTORNEYS PERMANENT MOLD AND METHOD FOR MAKING CAST 'CHAIN LINK John S. Nelson, Grand Island, N. Y. Application October Z, 1956, Serial No. 613,412

1 Claim. (Cl. 22-216) This invention relates to a permanent mold and a method for making cast link chain of aluminum or bronze. This application is a continuation-in-part of my prior application Serial No. 366,446 filed July 7, 1953 and now U. S. Patent No. 2,764,790.

Heretofore it has been customary to form the links for a chain from lengths of bar stock each of Which is bent into a ring and then Welding the opposing ends of the ring together. The use of such a method to form aluminum chain is not commercially feasible because of the difficulty and prohibitive cost of Welding aluminum.

It is also known to cast links which are used in chains but this is usually'done by forming the molds of sand which of course are destroyed in order to free the molded link. Such a method is also economically unfeasible and too slow for mass production.

While prior attempts have been made to' employ permanent molds for casting chain links, these attempts have' been singularly unsuccessful from a commercial stand point so that cast aluminum or bronze chain is unavail able on the market today and unheard of although there is a great need therefor.

Aluminum or bronze chain is desirable for use where the conventional iron or steel chain rapidly corrodes and requires frequent maintenance. Further because of its lighter weight aluminum or bronze chain is highly suited for ornamental purposes where the heavier iron chain' is now being used. Also, by using the proper aluminum or bronze alloys link chain having the desired strength properties can be produced.

It is therefore the principal object of the present invention to provide a permanent mold for making a cast aluminum or bronze chainlink interconnected with previously cast links.

Another object is to provide such a mold which can be used to produce commercial quantities of aluminumvor bronze chain in a practical and economically feasible manner.

Another object is to provide a multiple part mold which can be both rapidly assembled preparatory to the casting operation' and also quickly disassembled to free the link after it has been cast, 'the whole procedure taking only a matter ofseconds. b

' Another object is to provide such a mold which forms a chain link which requires little dressing up after being cast to makeit commercially acceptable.

Still another objectjof thejinvention is to providean improved method of making chains using permanent molds as aforementioned.

Other objects and advantages will be apparent from the following description and accompanying drawings in which:

Figure l is an exploded view in perspective illustrating a permanent mold for casting link type chain links, the Complementary mold halves being shown in open position;

Figure 2 illustrates in side elevation a closed mold,

such as shown in Figure 1, which is preheated prior to the pouring thereinto of molten metal;

Figure 3 is a view in elevation and illustrating the angular position of the mold of Figure 2 during pouring of the molten metal into the mold, and illustrating diagrammatically a mold hammer for hammering the mold during filling of the same with metal, the pouring ladle for delivery ofmolten metal being shown partly broken away; Figure 4 is an exploded View in side elevation illustrafi' ing the opening of the mold and removal of the cast chain link, the mold halves being shown in the position after being moved rectilinearly from each other and the cas linkremoved from the mold cavity; and i Figure 5 illustrates by a flow sheet the essential steps of casting chain links utilizing a permanent mold in ac# cordance with this invention.

I An important feature of the invention is the means which'I provide for venting the mold cavity when the molten metal is poured into `the cavity. Heretofore it has been generalpractice to provide 'circular vent holes but ings; the circular vent holes' were so large' that metal 'would flow into them leaving risers or projections on the cast article which sometimes rendered itdiflicult to open the mold and always required additional time for removing the risers or projections. I'have avoided all these ditficulties by providing very shallow but broad vents.

` In Figures l,through,4, I illustrate diagrammatically how the casting of ,chain links is carried out using a permanent mold and such as utilized for making chain links;

A permanent mold, as employed for casting links as shown, is more particularly described in'my copending application Ser. No. 366,446 filed July 7, 1953, now U. S.'

Patent No. 2,786,248.

The essential. steps ;of my process is further illustrated' by the flow sheet in Figure 5, and comprises ;(1) Establishing a source of molten metal from' which the chain link castings are *to be,made;.

(2) ;Providing a permanent mold having complementary mold cavities for forming the cast chain links, and which mold can be quickly opened for removal of the casting; 9 a 'i (3) The'permanent mold is arranged with its pouring gate upward andthe mold tilted atan angle of approximately 45- to the vertical, `and preheated to a temperature of about that of the temperature of the molten metal to be poured thereinto;

(4) Molten metal is then poured into the mold while thus tilted to avoid turbulence, and the'bottom of the mold is hammeredto assist in removal of occluded air' and ;gases fro-m the mold cavities and causedischarge of same through the mold cavity vents;

(5) .immediately thereafter andwithin 3 to 5 seconds after pouring of the' metal into the mold, the mold is opened and the' cast chain link removed to. prevent warping and sticking of the casting in the mold.

In casting chain links using permanent molds in accordance with this invention, it is important to carry out the pouring, solidifying and removal `of the casting in theshortes't' time possible to' produce soundcastings and,

' through 4, the Complementary mold 70, as illustrated in Figure l, comprises the Complementary mold halves 71 and 72 which define a link chain mold cavity 73. A pouring gate 74 is provided for communicating with the Patented Feb. 3, 1959 chain linkcavity as shown in-` Figure 1. Multiple vents 75, are, provided aroundthe mold. cavity on the mold, part 71 to provide for effective venting of air and occluded gases during casting. This use of multiple vents is very essential in: order} to produce sound. chain, link castings. p Complementary mold inserts'76; and: 77:'and can be closed and opened by'movement of the mold. parts .731 and 72 apart rectilinearly, the respective mold partsbeing accurately` positioned together `by the dowel pins 7.8.

After closing of the mold preparatory to making the casting, the, mold is heated as indicate-d, by the resistance heaterso, and the heatedmold then tilted to an the mold and it's solidification, the mold is opened as` by holding mold' part 71 Stationary or fixed and drawing away mold part 72 in a straight line path as indicated Mo-ld parts 71Land: 72 are, also provided with i by the arrow in Figure 4. The cast link 88 is then ejected a from the, mold cavity and thesprue portion removed' to provide afinished chain link.

, An important criterion of the method of casting chain links consists in carrying out the pouring and solidification of the casting in a very short period of time. This time. interval, as illustrated in Figure 5', takes approximately 5-10 seconds to complete Where the time is substantially increased, thereis difliculty in removing the` casting'from the' mold and the production of a sound casting.

i H'ammering 'of thermold while it is tiltedand receives i the molten metal is important to carry out simultaneously as the molten metal is poured into the'mold. Otherwise, there may be gaseous occlusions in the 'casting which would produce an unsatisfactory cast chain link.`

Further, it is necessary to preheat the mold to approximately of the temperature of the molten metal to be received in order to lengthen the life of the permanent mold and' prevent it'from warping or distortiug during successive casting operations.

In the casting of stud chain links using permanent molds in accordance with myinventiomtilting of the mold may be. dispensed with inasmuch as, due to the divided mold cavity construction, spattering and turbulence of the molten metal during' filling of the mold is generally not encountered; It is, however, preferred to tilt: the mold 'along the longitudinal 'axis of the chain link mold'. cavity in. order to allow the molten metal to roll into the mold from the ladle or pouring spout and thus avoid spattering and' the setting up of a turbulent 'flow of molten metal which tends to entrap and hold gases. Furthermore, by pounding or striking the bottom of the mold during the pouring of the metal into the mold, air or other gases in the mold cavity which may tend to be trapped and held by the molten metal is :caused to be discharged through the mold vents upon entry of the metal.

various metals and particularly of the light metals such as aluminum, magnesium and alloys thereof. Such alloy aluminum-.bronzes. may contain from 10 -15%, aluminum and the remainder of copper. Other metals may consist of substantially all aluininum or magnesium with added alloy elements such as nickel, copper, beryllium and the like, the latter alloying elements may be present in about 5-10% and the remainder aluminum or magnesium. Also chain links made of lead may be cast. Also babbitt type castings'may 'be made using alloys of copper and tin.

in accordance with this invention, castings may be made of aluminum or bro'nze or other metals in the production of chains and wherein permanent molds are used throughout the procedure. The casting of such chain links in permanent. molds, and particularly where the casting is made in a very short time and wherein the permanent mold can be opened .quickly following the reception of metal, provides an improved process of casting such products. y p

In this manner cast metal chain links can be produced in relatively large quantities and with suiiicient speed and facility so that themanufacture of such Chains corn- Inercially is now made practical. While the prior art indicates that castings can be made of chains it has not been possible heretofore to cast chain links in permanent molds and wherein. the same is carried out efiiciently and rapidly to produce castings Which are sound and rer quire substantially` little machining to produce a finished chain.

What is claimed is:

A method of making cast link Chains of aluminum' metal Which comprises the steps of' providing a permanent mold having Complementary mold parts formiug a` chain link mold cavity having a pluralityof spaced vents cornmunicating with said mold cavity-and pouring gate` for introducing molten metal thereinto, establishing a source of molten aluminum metal from which the chain linkcastings are to be made, positioning said moid to receive molten metal, preheating the mold, tilting the mold to an angle to the vertical and along the longitudinal axis of said chain link mold cavity, pouring molten aluminum metal into the mold in a quiet undisturbed stream while simultaneously vibrating the mold to assist the molten metal to enter the cavities of the mold and displace occluded gases, thereafter cooling the mold and immediately after solidification of the molten metal opening the mold and removing. the casting.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Gravity. Die-Casting Technique, by George W. Lowe. Preprint February 194.6, Hutchinsons Scientific 8e` Technical Publications, pages 93 and 94 Die castings, by H. H. Doehler, First Edition, 19,51, McGraw-I-Iill Book Co., pages 143-147.

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