US2643439A - Method of making plow bottom parts, particularly plowshares - Google Patents

Description

June 30, 1953 w. E. RUSKA 3,

METHOD OF MAKING PLOW BOTTOM PARTS, PARTICULARLY PLOWSHARES Filed Jan. 12, 1951 EICrzL 20d. 20a 20 20 20d Q 109 q ICrlO INVENTOR. i8

William E. Rus (la.

ATTORNEY Patented June 30, 1953 UNITED STATES ATENT OFFlCE METHOD OF MAKING PLOW BOTTOM PARTS, PARTICULARLY PLOWS-HARES Application January 12, 1951, Serial No. 205,769

3 Claims.

This invention relates to a method of making plow bottom parts, particularly plowshares, and has for an object the provision of improvements in this art.

One of the particular objects of the invention is to provide a method of making plow bottom parts, particularly plowshares, with a hardened surface which requires the least possible surface finishing work after hardening, whereby to leave a hardened surface covering of uniform depth.

Another object is to provide a method of making small plow bottom parts in pairs with an adequate holding and guiding element for handling the stock for a certain number of operations.

Another object is to provide a method of making plow bottom parts, especially plowshares, from stock having adequate holding and guiding means which also contributes to an improved procedure for severing the parts from each other and leaving a finished surface for each part and without improperly bending or distorting the parts.

Another object is to provide a method of making plow bottom parts which promotes improved and more uniform annealing of the stock.

Another object is to provide a method of making plow bottom parts which gives greater economy and facility of handling in the process as a whole.

The above and other objects and advantages of the invention will be apparent from the following description of an illustrative embodiment thereof, reference being made to the accompanying drawings, wherein:

Fig. 1 is a perspective view of a double-width rolled strip from which the parts are to be cut;

Fig. 2 shows a stack of fiat strips during annealing after hot rolling;

Fig. 3 is a plan showing how duplex or doublewidth single-length blanks are cut from the strip, the holes being punched in the same operation;

Fig. 4 shows the surface finishing or polishing operation on the double-width fiat stock;

Fig. 5 shows the press die bending operation on the double-width stock;

Fig. 6 shows the blanks being cut apart in the groove bottom by a milling cutter;

Fig. '7 shows the heat-treating operation in a case-forming atmosphere, such as a carburizing furnace;

Fig. 8 shows a quenching operation for harden- 111g;

Fig. 9 shows a finished part; and

Fig. 10 shows finished parts assembled on a plow bottom.

The method may be followed by reference to the accompanying drawings. The specific plow bottom part which is taken for illustration and to which the method can be applied with outstanding economy is a simple curved plowshare it having bolt holes It with squared countersunk portions for bolt heads, an upper joint edge I! adapted to fit against a moldboard, and a sharpened lower edge 18. It is desired that this part will have a hard jacket all over to resist wear and a soft core to provide resistance to breakage.

The original stock from which the parts are made consists of a flat rolled double-width strip 26 comprising identical sides 2%, 28b having a longitudinal center groove 26c defined by a flat bottom and convergent fiat sides. The bottom and sides join in an abrupt angle, thus providing a good line of securement for the strip in subsequent operations. The strip from opposite edges is tapered on one surface, as at 29d to form the lower bottom portion of the final share. The outer edges may be irregular due to varying amounts of metal in the strip fed to the rolls, hence cannot be depended upon for accurately guiding the stock in subsequent operations. The angular central groove does provide an accurate guide. The irregularities of the side edges are indicated in Fig. 1 but it is assumed that the strip is trimmed immediately after rolling or that it will be trimmed before the sides are out apart. The center groove also provides an accurate guide for this trimming operation.

After rolling (hot-rolling being understood) and while still hot, the flat strips are stacked for annealing (Fig. 2). If necessary, the strips may be reheated to a uniform temperature for annealing.

Next, the strip is out, as on lines 22 and 23 (Fig. 3) to form twin blanks 15a, E512 of unit length; In the same operation which cuts pairs of blanks from the stripwhich may consist of a single stroke of a press die-the holes l6 may be punched.

In another operation the holes are countersunk while the metal is still soft.

Next, and while the stock is still flat and soft, the surfaces are ground or polished, or both, to provide the final dimensions. This is very economical, due to the fact that the stock is still soft and still fiat (Fig. 4). Plow bottom shapes are usually very irregular, from a geometrical standpoint, and it is very difficult and expensive to grind and polish the surfaces after the parts are formed. to final shape. It is especially difiicult after the parts have been hardened. Finishing at the early stage is especially economical because two parts are finished at one and the same operation.

The parts are bent to final shape. This could be done after treatment for hardening (to be described) and with the same heat before final cooling to harden; but for greater economy and because the final parts are small and non-symmetrical, it is preferable to bend the parts to shape immediately after polishing. This may be performed by the single stroke of a press die. The metal is still soft and easily bent and two parts are cold-shaped at a single operation (Fig 5).

The twin blanks are next cut apart. This may be done by a milling cutter which cuts out the bottom of the groove to separate the parts and at the same time form the upper joint line of the share. The groove provides an accurate guide for this operation. The milling operation makes so smooth 2. surface at the joint edge that no further surfacing operation i necessary here (Fig. 6).

Next, the blanks are placed on edge in a tray and heated in a suitable atmosphere to give them a hardenable outer jacket completely surrounding a soft core. In the present instance the blanks are given a carburizing treatment, as in a carburizin furnace 25, a number of blanks being carried by each tray 26 (Fig. 7)

Subsequent to the penetrating furnace treatment the blanks are placed in a suitable bath to harden them. A salt bath, as in a tank 2! has been used with good results (Fig. 8)

The earth-engaging edge is ground to sharpen it and the part is then ready to secure on a plow bottom along with a moldboard and landsicle. The saddle or frog to which the parts are secured is not shown. After assembly, the entire front may be given a finish polishing which, at the same time, smooths the joint line.

It will be seen that the method, especially in the preferred form for plowshares, is very efficient and economical. By using double-width stock, each operation serves two parts; by working on flat stock as far as possible, the surface finishing operations are made accurately and inexpensively; by using an angular medial groove the double-width parts are held accurately regardless of edge irregularities; and by shaping to proper curvature before subjecting the parts to a heating and quenching operation to provide a hard jacket, it is possible to handle the articles in large numbers in carrying trays, whereas they would have to be handled individually if they were shaped to contour after the jacket-forming operation.

It will thus be seen that the invention provides a simple, convenient and economical process for forming hard-jacketed soft-core parts of complex shape, as for plow bottoms; also, an improved product results because there is substantially no cutting into the surface of the hard jacket after it is formed.

While one embodiment of the invention and certain modifications have been described for purposes of illustration, it is to be understood that there may be various modifications within the general scope of the invention.

What is claimed is:

1. The method of making plow bottom parts of curved shape with bolt holes and a finished joint edge, which comprises, rolling a double width strip in the flat with a deep fiat-bottomed angular-cornered groove down the middle on one side, annealing the strips in the flat in a stack, cold-cutting double width blanks in the flat from the annealed strip stock, forming bolt holes and bringing the blanks accurately to final surface shape, bending the stock to final curvature, cutting the blanks apart and finishing the joint edge by a milling cutter while holding and guiding the stock by the center groove, oven treating and hardening the shaped and surface-finished parts to give them a hard jacket all over and a soft core, and finally light grinding and polishing the parts.

2. The method of making plowshares of curved shape with bolt holes and a finished upper joint edge, which comprises, rolling a double width strip in the fiat with a deep angular-cornered groove down the middle on one side, annealing the fiat strips in a stack, forming the holes and exterior surface to finished shape in the flat double width, bending the double width stock to final curved shape, cutting the finished blanks apart by a milling cutter which cuts out the full width of the bottom, treating the finished shares to give them a deep hard jacket over a softer core, and finish polishing the hard jacketed shares without materially thinning the hard jacket at any place.

3. The method of making a curved plow bottom part, which comprises, providing a fiat annealed double-width rolled strip with a deep angularcornered groove down the middle on one side, cutting double width pieces from the flat stock. finishing the surfaces to final shape and forming bolt holes in the pieces if required while in the fiat, cutting the pieces apart by milling out the bottom of the groove, forming a hard jacket on all surfaces with a soft interior core, bending the parts to final shape after the parts are cut in double width from the strip stock and before final cooling to harden, and finally polishing the parts without appreciably thinning the hard jacket at any place.

WILLIAM E. RUSKA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,603,199 Erickson Oct. 12, 1926 2,306,996 Altgelt Dec. 29, 1942

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