US2349397A - Apparatus for forming bearing metal surfaces on backing metals - Google Patents

Description

May 23, 1944.

, c. M. ANGEL 2,349,397

APPARATUS FOR FORMING BEARING ME TAL SURFACES ON BACKING METALS Original Filed Nov.' 24, 1941 Patented May 23, 1944 UNlTD .STAES i ATENT OFFICE APPARATUS F03 FORMING BEARING METAL SURFACES ON BACKING METALS I Charles M. Angel, Huntington, W. Va.

4 Claims. ,(Cl. 22-423) This invention relates in general to an improved apparatus for forming bearing surfaces or liners of copper alloys or the like on objects made from a different metal such as cast iron, steel or the like. The present application is a division of my co-pending application Serial No. 420,210, filed November 24, 1941.

More specifically, the invention as shown herein is directed to an improved apparatus for forming and reconditioning shoe and wedge faces, hub liners, and journal brasses on locomotive driving boxes, by fusing a copper alloy or other suitable nonferrous metal to a backing of ferrous metal. However, it will be understood that the apparatus may be employed for forming and reconditioning other locomotive and railroad car parts and bearings which are used for other purposes.

Heretofore, it has been the practice to form shoe and wedge and hub liners on locomotive driving boxes, by pouring molten bronze on the backing metal and securing the bronze in place by means of tap bolts and dovetail sections in the steel or other ferrous backing material. Considerable difficulty has been experienced in obtainin satisfactory, durable driving boxes when formed in this manner since it has been found that the metal of the bearing surfaces or liners are not fused to the backing metal and the surfaces crack, separate from the backing material during use or become loose around tap bolts and in dovetail sections, making early replacement necessary.

Accordingly, a principal object of the instant invention is the provision of a means whereby the bearing surfaces or liners are made an integral part of the backing metal and an improved union between the two is obtained.

Another important object of the invention is the provision of improved means whereby the liners may be reconditioned by a building up method, this apparatus being used to predetermine the depth to which the bearing metal will be added so that a substantially accurate bearing formation is obtained by a casting process which requires a minimum amount of skill on the part of the operator.

To attain the foregoing object, I have provided herein a system of spillways which permit excessive amounts of molten metal to be applied to the backing metal or to the worn lining metal, these spillways taking away the excess metal when a predetermined thickness is obtained, and transmitting the same to an ingot mold where it is available for remelting.

I have found that the above recited additive process of forming liners by fusing the same to the backing metal is additionally improved by the application of excessive amounts of molten hearing or liner metal to the backing metal in such a manner that the molten metal flows freely past the surface to which it is to be fused, for a somewhat prolonged period of time, that is throughout the time of the pouring operation. A further important object of the invention is, therefore, the provision of a means for obtaining this prolonged period of flow without necessitating the exercise of great skill on the part of the operator whereby the liners may be formed easily, rapidly, efficiently, and economically.

A further object of the invention is the provision of a means for splitting the hub liner casting to allow for expansion and contraction during thepouring and subsequent cooling of the molten metal, and thus avoid cracking and separation from the backing metal; and also to allow for movement of the driving box under impact in service should strains occur which would cause the liner to crack.

Another object of the invention is the provision in conjunction with the above apparatus, of an improved method of establishing or applying an initial deposit of the bearing alloy on the backing metal to improve the union of the parts.

It will be understood that th apparatus herein described, may be applied for reconditioning worn bearings or liners as well as for the preparation or forming of entirely new surface bearlugs, and that where the surface to be covered by the bearing, driving box surface, or like expressions are used, they are directed to either the actual surface of the driving box proper or to the worn surface of old bearings or liners which are being reconditioned.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the'following description, which,

when taken in" connection with the accompanying drawing, discloses a preferred embodiment thereof.

In the drawing,

Fig. 1 is a top plan View of the apparatus used for forming the hub liner on a locomotive driving box;

Fig. 2 is a side elevational view of the apparatus shown in Fig. 1;

Fig. 3 is a cross sectional view taken on the line 6 -6 of Fig. 1; I

Fig. 4 is a fragmentary cross sectional view of a modified form of the apparatus.

Referring to the drawing, and more particularly to Figs. 1, 2 and 3 thereof, the entire assembly shown rests upon a suitable fireproof plate It]. A locomotive driving box II to be treated in accordance with the instant invention, is placed upon the plate I with the worn hub liner or hub liner surface extending upwardly from the plate IE1. The driving box shown is of standard construction and includes a body I2, attachment flanges l3 and l3a and attachment lugs 14.

Preferably before the bearing parts are cast to the box II as hereinafter described, the box is so treated as to deposit a film of the bearing alloy to the surfaces thereof. One method of accomplishing this is to place copper or copper alloy turnings upon the surfaces to a depth of far" to /8" and fuse the same thereto with a carbon are using approximately 587 amperes at 80 volts. It will be understood, however, that the current used may vary widely under varying conditions of operation and of materials being worked upon. Another method is to use a hearing alloy brazing rod and apply the film with an oxyacetylene torch. Another highly satisfactory method is to electroplate a film of bearing metal such as copper or copper alloy to the surfaces. By so applying a film of the bearing metal to the surfaces, an initial deposit is obtained which is securely fused and united with the driving box surfaces so that the later union of the bearings proper to the driving box H, is facilitated. After this initial layer of bearing metal is formed, the surface thereof is cleansed as by pickling or by bombardment with steel shot, or blasted with an abrasive material, or any other suitable method of cleansing the surface may be employed.

As previously explained, there are two important factors which concern the casting of the bearing metal on the surfaces of the driving box N. First, it is highly desirable that the molten metal be poured in excess of the volume required for the bearing and that the excess metal flow freely past the surface where fusion occurs, thus maintaining the temperature of the surface at that of the molten metal. In using such a method it is of course, necessary that the path of flow of the molten metal be so directed that continuous flow past said surface is obtained throughout the pouring operation and so that the excess metal is properly disposed of without blocking off or damming up the flow. Secondly. it is highly desirable that as the pouring progresses and the approximate dimensions of the desired bearing are reached, further increase of the bearing dimensions cease and that the excess metal poured thereafter be disposed of after passing through the mold cavity. To the end that the above character of flow be obtained. spillways are provided which have predetermined levels and which afford an exit for the excess of molten bearing metal and at the same time determine the path of flow of the metal and insure flow past the surface to which the hearing or liner is to be attached.

The assembly shown in Figs. 1, 2 and 3 is that presently preferred for forming the hub liner on the hub liner surface of the driving box H. A fire-proof plate I 0 of suitable material is employed and the driving box is placed thereon with hub liner surface extending upwardly from the plate ID. The hub liner cavity 32 is formed by the upwardly extending crown surface 33 of the drive bearing cast as hereinbefore described. 78

the inner wall of a casting ring 34 and the inner surfaces of fireproof strips 35.

Since the hub liner bearing is relatively thin, difiiculty has been experienced in the past by the cracking and separation of the hub liner bearing from the backing metal because of the expansion and contraction which occurs while pouring and cooling the bearing metal. To overcome these difiiculties, the hub liner shown herein is divided.

Suitable spillways are provided to prevent the bearing from being formed excessively large, yet to allow an excess amount of metal to be poured into the mold cavity.

In the present instance, a sand core 31 is formed with a lower portion 38 having an ingot mold 39 formed therein. The strips 35 extend downwardly into the sand core for stability and rest on the plate l0. Spillways 35a are provided in the upper ends of strips 35, and the bottoms of said spillways are at the approximate height of the top surface of the cast hub liner. These spillways 35a lead into suitable ducts M! which unite to form a duct 4| leading to the ingot mold 39.

It will be seen from the foregoing that as molten bearing metal is poured into the two parts of the hub liner defined by the strip 36, the ladle being preferably manipulated through the paths shown by the arrow E, F, G and H, it will fill the cavity to the desired depth as defined by the bot toms of spillways 35a. Thereafter, the excess of molten metal will overflow into the ducts 40 and 4| and thence into the ingot mold for remelting.

The path of the molten metal circulates throughout the cavity, but it is to be noted that no hydraulic head is created since the depth of the cavity is not sufficiently great to require the use of such an expedient.

It is also to be noted that since the protruding crown surface 33 of the drive bearing previously cast, serves as one wall of the hub liner cavity, a strong bond is formed between the drive hearing and the hub liner and this provides a much stronger and more durable bearing structure.

In the event that the hub liner, together with the adjacent end of the drive bearing, which forms a coextensive surface therewith, becomes worn, it will be seen that the bearing may be conveniently reconditioned by forming a new layer of the bearing metal on the surface of the hub liner and upon the adjacent end of the hearing, this being accomplished by a single pouring. Preparatory to this operation, it is merely necessary to place the cast ring 34 and strip 36 in the positions shown in Figure 1 after the old surf-aces have been suitably cleaned as earlier described. Additionally, a casting ring 49 is set up against the crown surface of the drive hearing and extends thereabove to the proper height. With such a construction the spillways 35a shown in Figure 1, may be utilized in the manner previously described. (See Figure 4.)

It will be understood that whenever a bearing surface so applied becomes worn, it can be reconditioned and restored to its original size by employing the apparatus herein described. Care should be taken to have the part to be rebuilt cleaned and preheated to proper temperature before applying additional bearing metal.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the devices mentioned herein without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the forms hereinbefore described being merely a preferred embodiment thereof. 1

Iclaim:

1. In apparatus for forming hub liner bearings on a locomotive drive box or the like, a hub liner mold cavity having the driving box hub surface as its bottom wall, a hub liner casting ring for its outer wall, and the drive bearing crown surface for its inner wall, walls of fireproof material at the legs of said surface, spillways which form a dam for molten metal in said fireproof walls, an insert wall of fireproof material, said insert wall resting edgewise on the hub surface and being adapted to divide said hub liner bearing into two sections, a sand core adjacent said fireproof Walls, an ingot mold in said sand core, ducts in said core for conducting molten metal away from said cavities as defined by said insert wall, to said ingot mold.

2. In apparatus for forming hub liner bearings on a locomotive driving box or the like, a hub liner mold cavity having the driving box hub surface as its bottom wall, a hub liner casting ring for its outer wall, and the drive bearing crown surface for its inner wall, walls of fireproof material at the legs of said surface, spillways which form a dam for molten metal in said fireproof walls, an ingot mold associated with said cavity, ducts for conducting molten metal from said spillways to said ingot mold.

3. In apparatus for forming hub liner bearings on a locomotive drive box or the like, a hub liner mold cavity having the driving box hub surface and the adjacent coextensive end surface of the drive bearing as its bottom wall, a hub liner casting ring for its outer wall, an inner wall, said last named wall comprising the surface of a casting ring member positioned flush with the crown of the drive bearing and extending thereabove, and spillways associated with said walls, the overflow levels of said spillways being in the plane of the desired surface height of the hub liner bearing being formed.

4. In apparatus for forming hub liner bearings on a locomotive driving box or the like, a hub liner bearing mold cavity, the hub liner surface of the driving box constituting the bottom wall of said cavity, means for forming the remaining walls of said cavity, spillways in the walls of said cavity, the overflow level of said spillways being in the plane of the desired surface height of the hub liner bearing being formed.

CHARLES M. ANGEL.

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