US2151568A - Method of forming brake drums - Google Patents

Description

March 2 939- c. w. SINCLAIR METHOD OF FORMING BRAKE DRUMS Filed Sept. 14, 1936 FIG.

R mm mm NS w s E L R A H c I A rromws 12s FIG.5.

Patented Mar. 21, 1939 UNITED STATES PATENT ()FFI METHOD OF FORMING BRAKE DRUMS Application September 14, 1936, Serial No. 100,784

7 Claims.

The invention relates to the manufacture of brake drums and refers more particularly to the manufacture of composite brake drums.

One of the objects of the invention is to pro- 5 vide an improved brake drum constructed to be of relatively light weight and at the same time making provision for the heat generated by the application of the brake. Another object of the invention is to manufacture the brake drum by an improved and economical method whereby a material saving in metal is effected and at the same time a strong, substantial construction of brake drum is produced.

These and other objects of the invention will become apparent from the following description, taken in connection with the accompanying drawing, in which Figure 1 is a plan view of a blank used in the manufacture of the brake drum;

20 Figure 2 is an end view of the blank of Figure 1;

Figures 3 and 4 are elevations illustrating different steps in the method;

Figure 5 is a section illustrating another step in the method;

Figure 6 is a section illustrating the completed brake drum.

In general, I start with strip stock having a longitudinally extending portion of substantially uniform gauge and an adjacent longitudinally extending portion of a gauge decreasing in a direction from the first mentioned portion. This stock is hooped and its ends are welded together, after which the portion of varying gauge is contracted. During the contraction the metal is upset to a gauge not greater and preferably less than that of the first mentioned portion. Then a web is secured to the free end of the contracted portion to complete the brake drum. By reason of forming the brake drum in this manner, the portion of substantially uniform gauge is at least as thick and preferably thicker .than the remaining portion. Its gauge is suificient to form a sufficiently heavy body which may be used as the brake engaging portion and which will serve to store and distribute and dissipate the heat generated by the application of the brake. By reason of the contracted portion, the size of the web, which may be a fixed flange upon a hub, is reduced to thereby reduce the total weight. The reduction of the total weight is also effected by starting with a blank having a portion of tapered section.

In carrying out my method, I start with the sheet metal blank I, illustrated in Figure 1. This blank is formed from strip stock andis symmetrical with respect to its longitudinal median axis. As shown, it has the edge portions 2 of substantially uniform gauge and the middle portion 3 of a varying gauge, this middle portion decreasing in gauge from the edge portions to the longitudinal median axis of the blank. The blank I is cut to length, after which it is hooped, its ends are Welded together and the weld flash is removed to form the annular member l, illus trated in Figure 3.

The blank I may be severed along its longitudinal median axis 1', either before forming the annular member 4 or after this annular member is formed. In either case, each of the resulting blanks may be flanged at one end to provide the annular flanged member 5, illustrated in Figure 4, the flange 5 extending radially outward- 1y at the free end of the edge portion of substantially uniform gauge.

The annular flanged member 5 is then operated upon by the die 6, which comprises the female die member I and the male die member 8, which cooperate to contract the portion 3 of varying gauge, which portion decreases progressively from the portion 2 of substantially uniform gauge. These die members form the tapered portion 9 having at its free end the approximately cylindrical part it. During the contraction, the metal which forms the tapered portion 9 is upset to a gauge preferably less and, in any event, not greater than that of the portion of substantially uniform gauge.

After the forming of the annular member 5, the web II is located within the approximately cylindrical part iii and fixedly secured thereto. This web ll may be formed of sheet metal and welded in place and adapted to be secured to a wheel hub. Figure 6 illustrates the completed brake'drum.

With this method, it will be seen that a strong, substantial construction of brake drum is secured having a brake flange which is formed from the edge portion 2 of the blank and which is of sufficient body to take care of the heat generated by the application of the brake. It will also be seen that by reason of the tapered portion 9, which is formed from the portion 3 cf the blank of varying gauge, the total weight of the brake drum is reduced, both by reason of the portion 3 being of less gauge and by reason of the decrease in diameter of the web. Furthermore, the construction is such that the brake flange is properly axially offset with respect to the Web.

What I claim as my invention is:

1. The method of forming a sheet metal brake drum, comprising providing a sheet metal tubular blank having an annular brake engaging portion and an annular portion decreasing in gauge from the brake engaging portion, contracting the last mentioned portion and thereby upsetting the metal thereof, during the contracting forming a tapered part and an approximately cylindrical part at the free end of the tapered part, and then securing a web to the approximately cylindrical part.

2. Those steps in the method of forming a brake drum which consist in forming a substantially flat strip of stock with a longitudinal edge portion of substantially uniform gauge and with the opposite longitudinal edge portion varying in gauge from the first portion, fashioning the strip of stock to form a tubular blank, contracting the portion of the tubular blank of varying gauge in a manner to progressively upset the material thereof to form a radially inwardly inclined section provided with a reduced substantially cylindrical portion, and securing a web to the cylindrical portion.

3. Those steps in the method of forming a brake drum which consist in forming a tubular blank with an annular brake flange engaging portion and with an annular portion decreasing in gauge from the brake engaging portion, and upsetting the material of the annular portion of decreasing gauge by contracting said annular portion.

4. Those steps in the method of forming a brake drum which consist in fashioning a tubular blank from a strip of stock having a portion of one longitudinal edge progressively decreasing in gauge from the longitudinal center line of the strip of stock, and upsetting the annular portion of the tubular blank of progressively decreasing gauge by contracting said last named portion.

5. Those steps in the method of forming a brake drum which consist in fashioning a tubular blank from a strip of stock having the opposite longitudinal edge portions respectively of substantially uniform and varying gauge, and contracting the annular portion of the tubular blank of varying gauge to upset the material in the latter portion to a gauge not greater than the substantially uniform gauge of the first named portion.

6. Those steps in the method of forming a brake drum which consist in providing a strip of stock having a portion of one longitudinal edge of uniform gauge and having the portion at the opposite edge decreasing in gauge from the portion of uniform gauge, hooping the strip of stock to form a tubular blank, and progressively contracting the portion of the tubular blank of varying gauge in a manner to progressively upset the material thereof.

'7. Those steps in the method of forming a brake drum which consist in forming a tubular blank from a strip of stock having a portion of one longitudinal edge of substantially uniform auge and having the portion of the opposite edge decreasing in gauge from the portion of uniform gauge, contracting the portion of the blank of varying gauge, and securing a mounting member to the contracted portion.

CHARLES W. SINCLAIR.

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