US3445893A

US3445893A - Apparatus for compacting a metal powder brake track

Info

Publication number: US3445893A
Application number: US629732A
Authority: US
Inventors: Charles Robert Talmage
Original assignee: Motor Wheel Corp
Current assignee: Motor Wheel Corp
Priority date: 1967-04-10
Filing date: 1967-04-10
Publication date: 1969-05-27
Anticipated expiration: 1986-05-27

Description

APPARATU OR COMPACT y 1969 c. R. TALMAGE 3,445,893

ING A META P ER BRAKE TRACK Original Filed Feb. 5, 1964 Sheet of 4 FI6.7 (86 0 222% a If uo g r g 24 FIG. 3

321 F a L100! 3e INVENTOR. CHARLES ROBERT TALMAGE j:

ATTORNEYS y 1969 c: R. TALMAGE 3,445,893

APPARATUS FOR COMPACTING A METAL POWDER BRAKE TRACK Original Filed Feb. 3, 1964 Sheet 2 of 4 ALL {I H H II 4/\H 74 INVENTOR. CHARLES Rosam- TALMAGE ATTORNEYS y 1 C. R. TALMAGE APPARATUS FOR COMPACTING A METAL POWDER BRAKE TRACK Original Filed Feb. 5, 1964 Sheet 3 of 4 ATTORNEYS United States Patent 3,445,893 APPARATUS FOR COMPACTING A METAL POWDER BRAKE TRACK Charles Robert Talmage, New Canaan, Conn., assignor to Motor Wheel Corporation, Lansing, Micl1., a corporation of Michigan Continuation of applications Ser. No. 342,159 and Ser. No. 342,121, Feb. 3, 1964. This application Apr. 10, 1967, Ser. No. 629,732

Int. Cl. B21d 53/50 US CI. 18-36 9 Claims ABSTRACT OF THE DISCLOSURE For purposes of summarizing this disclosure and not by way of limitation, a steel brake drum shell is lined with sintered iron by compacting ferrous powders directly into the shell. The shell with the compact therein is then heated to sinter the ferrous powders and bond the track to the shell. The shell has a cylindrical body open at the front end thereof. The back end of the shell may be either open, partially closed by a radial flange to which a drum back is to be attached, or substantially closed by an integral back portion of the shell. The ferrous powders are compacted into the shell by a press having an upper die that retains the shell therein with the front open end of the shell opening downwardly. A lower set of dies includes a core die axially movable into the shell to form a brake track mold. The press is constructed so that the core can either move through the back or bottom thereon depending on whether the back is open, partially closed or substantially closed. The lower dies are arranged to form an annular receptable for receiving ferrous powders to be compacted into the shell. The bottom of the receptacle is closed by an annular punch movable relative to other parts of the lower die. When the press is operated, the punch transfers the ferrous powders from the receptacle to the mold and compacts the powders therein in direct contact with the shell.

This application is a continuation of my copending applications Ser. No. 342,121 and 342,159, both of which were filed Feb. 3, 1964 and originally entitled Method and Apparatus for Compacting a Metal Powder Lining and are now abandoned.

This invention relates to apparatus for making an article having a sintered metal lining and in particular to apparatus for making a brake drum having a sintered metal brake track secured in a brake drum shell of the type referred to hereinabove.

This invention contemplates lining such shells with a sintered metal sloove by apparatus that are economical and efiicient; that decrease the likelihood of fracturing the metal powder sleeve prior to the sintering operation; and that assure intimate contact between powder in the sleeve and the shell being lined.

In the drawings:

FIG. 1 shows a finished brake drum looking into the cavity thereof, the brake drum having a sintered metal brake track secured in an open-ended shell;

FIG. 2 is an enlarged fragmentary section taken through line 22 of FIG. 1;

FIG. 3 is a fragmentary view illustrating an openended brake drum shell of the type shown in FIG. 2 where metal powder has been compacted directly within the shell;

FIG. 4 is a fragmentary vertical section illustrating an exemplary tool set of the type used in fabricating the article illustrated in FIG. 3 by compacting metal powder directly within the brake drum shell;

ICC

FIG. 5 is a fragmentary view illustrating a portion of the tool set shown in FIG. 4 just before the metal powder is compacted;

FIG. 6 is a fragmentary view showing a portion of the tool set illustrated in FIG. 4 after the metal powder is compacted within the brake drum shell;

FIG. 7 is a fragmentary view illustrating the general applicability of the instant invention in lining any openended cavity with sintered metal;

FIG. 8 is a fragmentary view illustrating another embodiment of the instant invention where the upper die is modified to accommodate a different form of brake drum shell;

FIG. 9 shows another embodiment wherein the brake drum has a sintered metal brake track secured in a closedend shell;

FIG. 10 is an enlarged fragmentary section taken through line 1010 of FIG 9;

FIG. 11 is a fragmentary view illustrating a brake drum shell of the type shown in FIG. 10 where metal powder has been compacted directly within the shell;

FIG. 12 is a fragmentary vertical section taken through the tool set of a press used to form the article illustrated in FIG. 11 by compacting metal powder directly within a shell or cavity;

FIG. 13 is a fragmentary view illustrating the tool set shown in FIG. 12 just prior to compacting the metal powder;

FIG. 14 is a fragmentary view showing the tool set illustrated in FIG. 12 after the metal powder is compacted within the shell; and

FIG. 15 is a fragmentary view illustrating the general applicability of the instant invention in lining any closedended cavity with metal powder.

By way of description and'not for puropses of limitation, FIGS. 1 and 2 show a finished brake drum 6 comprising a generally cylindrical steel shell 8, a brake track 10 that lines the inner cylindrical surface 11 of shell 8, and a drum back 12 which is welded to a radially inward extending flange 13 on shell 8. The radially inward edge 14 of flange 13 forms a circular aperture having a diameter equal to the diameter of the inner cylindrical surface 15 of brake track 10. Shell 8 also has an outwardly flared portion 16 that forms a dust seal when drum 6 is assembled with other brake parts. Back 12 is provided with a central aperture 17 and bolt holes 18 for assembling drum 6 on other wheel parts. Brake track 10 is composed of a sintered ferrous powder blend, primarily iron powder, together with graphite and a suitable lubricant.

In accordance with this invention, brake drum 6 is fabricated by compacting a sleeve 20 (FIG. 3) of ferrous powder blend in direct contact with flange 13 and the inner cylindrical surface 11 of shell 8.

FIG. 4 is a fragmentary vertical section illustrating a tool set for use in a press to compact sleeve 20 (FIG. 3) within shell 8. An upper female die 22 is mounted on a die shoe 24 which is carried on a. ram (not shown) of the press. Die 22 has a generally cylindrical cavity 26, a counterbore 28 and an annular shoulder 29 formed between cavity 26 and a bore 30 that extends throughdie 22. Cavity 26, counterbore 28 and shoulder 29 conform closely to the contour of shell 8 so that shell 8 is retained within cavity 26. Bore 30 has a diameter equal to the dimeter of the aperture bounded by edge 14 of flange 13. A plurality of slideable pins 31 are provided to eject shell 8 from cavity 26. The lower tools include an annular confining die 34 and a cylindrical core 36 spaced concentrically and radially inward of die 34 to form an annular receptacle 38 therebetween. Receptacle 38 is closed at its lower end by an annular compacting punch 40. Receptacle 38 and punch 40 have radial thicknesses corresponding to 1 radial thickness of sleeve 20. Core 36 is dimensioned fit closely but slideably in the aperture in shell 8- boundby flange 13 and also fit closely but slideably within re 30. Die 34 has an integral annular boss 41 having an ter contour adapted to fit snugly within the outwardly red portion 16 of shell 8. An inner cylindrical surface of die 34 and an outer cylindrical surface 43 of core are vertically aligned, respectively, with the inner lindrical surface 11 of shell 8 and the edge 14 of nge 13. Die 34 is mounted on a vertically movable platen 44 rich, in turn, is supported on a vertically movable platen by a plurality of vertical rods 48. Platen 46 also suprts core 36 through a vertical post 50, a vertically movle platen 52 and a power cylinder 54 having a fluid tuated piston 56 for moving core 36 upward relative both platen 52 and die 34 into engagement with shoe Rods 48 and post 50 are vertically movable through itable dimensioned apertures 58 and 60, respectively,

a stationary platen 62. Punch 40 is mounted directly platen 62. Platen 46 is arranged to float with respect platen 62 and punch 40. To this end a plurality of ver- :al rods 64, each of which is secured to platen 46, exnd downward through respective openings 66 in a stamary lower platen 68. Compression springs 70 surroundg respective rods 64 each engage the lower surface of aten 46 and the upper surface of platen 68 to urge aten 46 upward. Nuts 72 are threaded on the lower [d8 of rods 64 and engage platen 68 to limit upward avel of platen 46. With this arrangement, platen 46 can moved downward toward platen 68- against the action springs 70 so that die 34 and core 36 move downward :lative to punch 40 which is stationary.

With the press open as shown in FIG. 4, shell 8 may inserted into die 22 and retained therein by friction r suitable die holders (not shown). Receptacle 38 is then larged with a quantity of a ferrous powder blend 74 lfficient to be compacted into a sleeve (FIGS. 3 and having a height equal to the height of shell 8. The comacting operation is initiated by lowering the ram (not town) of the press which carries die 22 downward. Die 2 descends until it bottoms on die 34. Core 36 is then loved upward by piston 56, past flange 13 and through ore into engagement with shoe 24. FIG. 5 shows to position of the dies after die 22 has bottomed on die 4 and core 36 has bottomed on shoe 24. The space be- :veen the outer cylindrical surface 43 of core 36, flange 3, and the inner cylindrical surface 11 of shell 8 along 11th the inner cylindrical surface 42 of boss 41, forms an nnular mold 76. As the ram continues downward, die 22 nd shoe 24 push die 34 and core 36 downward relative o punch which is stationary so that iron powder 74 s compacted within mold 76 by punch 40 to form sleeve .0 in tight assembly with shell 8 (FIG. 6). Suitable stops tre provided in the press to terminate the downward novement of the ram when punch 40 has formed sleeve .0 to the proper height. During the compacting operation, .prings 70 are compressed to maintain die 34 and core 56 in tight engagement with die 22 and die shoe 24, re- .pectively. After the compacting operation is completed, lie 22 is raised away from die 34 and core 36 so that $11611 8 having sleeve 20 therein may be ejected from die 22 by pins 31.

Shell 8 with sleeve 20 therein is then heated to a tem- Jerature of approximately 2050 F. to sinter the ferrous powder in sleeve 20. Sleeve 20 may be formed of a growthtype ferrous powder blend to insure a tight joint between shell 8 and sleeve 20. Alternatively, sleeve 20 may be infiltrated and also brazed to shell 8 during the sintering operation with copper, copper alloy or other material having a melting temperature within the sintering temperature range of the ferrous powder.

By way of example, a ferrous powder blend primarily iron powder sieved through a 100 mesh per inch screen, together with graphite and a suitable lubricant, may be compacted at approximately 60,000 pounds per square inch. Depending on the density of the powders, the vertical height of receptacle 38 will be in the range of two to two and one-half times the height of shell 8 in order to accommodate a quantity of loose powder sufl'icient to form sleeve 20.

The invention described hereinabove also contemplates compacting a metal powder lining within shells having various shapes so long as one end is open and the other end is substantially open. FIG. 7 is a fragmentary view illustrating a generally cylindrical shell 80 having a radially inward extending flange 82 at one end thereof. An annular sleeve 84 of ferrous powder blend may be compacted tightly within shell 80 in direct contact with flange 82 and the inner cylindrical surface 86 of shell 80 in accordance with the method hereinbefore disclosed. The radially inner surface 88 of sleeve 84 is aligned with the radially inner edge 90 of flange 82. The shape of the cavity in the upper female die must conform closely to the outer contour of shell 80 so that radial and longitudinal distortion of shell 80 is restrained during the compacting operation. The core is suitably dimensioned so as to be movable through the opening bounded by edges 90 of flange 82.

In the embodiment illustarted in FIG. 8 brake drum shell is in the form of a straight cylinder. An upper female die 102, corresponding to die 22 in FIGS. 4 through 6, has a vertical annular recess 103 which receives the upper end portion 104 of shell 100. Die 102 is also formed with an annular shoulder 106 which registers with bore 108 that corresponds to bore 30 in FIGS. 4 through 6. Suitable pins 110 may be provided to eject shell 100. When core 36 bottoms on shoe 24, shell 100, shoulder 102, and core 36 define an annular mold corresponding to mold 76 in FIG. 5. With this arrangement, the end portion 104 of shell 100 can be formed to final shape after the brake track has been sintered and firmly bonded to shell 100. For example, portion 104 can be formed into a flange corresponding to flange 13 in FIGS. 1 through 3 or into various forms of dust seals corresponding generally to the outwardly flared portion 16 in FIGS. 1 through 3.

Although for purposes of illustration, die 34 has been disclosed as having boss 41 adapted to flll the outwardly flared portion 16 of shell 8, it will be apparent that portion 16 could be filled by a number of suitable devices. For example, as disclosed hereinafter in connection with FIGS. 9 through 15, boss 41 could be formed on the top portion of a separate inner ring. The upper tip of the inner ring is flush with an outer confining ring that floats with respect to the inner ring so that the outer ring can move down relative to the inner ring until the inner ring bottoms on portion 16.

Although the apparatus of the invention described hereinabove has been disclosed as having a core 36 which is moved upward with respect to die 34 by a piston 56, a core identical to core 36 could be fixed relative to die 34 in a position extending above die 34 so that die 22 and shoe 24 would bottom simultaneously on die 34 and the fixed core, respectively. The core 36 and die 34 would then move downward in unison with die 22 and shoe 24. Alternatively, core 36 could float with respect to die 34 so that after die 22 bottoms on die 34, core 36 would remain vertically fixed until it bottomed on shoe 24. Further downward movement of die 22 and shoe 24 would push core 36 and die 34 downward in unison relative to punch 40. In either situation, core 36 could be positioned within bore 30 and preferably in engagement with shoe 24 before any significant compaction of powder 74 occurs.

Referring to the embodiments of FIGS. 9 through 14, a finished brake drum 206 comprises a generally cylindrical steel shell 208, a back 210 formed by a radially inward extending flange integral with shell 208, and a sintered metal brake track 212 that lines the inner cylindrical surface 213 of shell 208. Back 210 is provided with a central aperture 214 and a plurality of bolt holes 216 for assembling drum 206 on other wheel parts. Shell 208 also has an outwardly flared portion 218 which forms a dust seal when the drum is assembled with other brake parts. Except for the integral back 210 and corresponding modifications in the press for making drum 206, the embodiments to be described are similar in many respects to those described hereinabove in connection with FIGS. 1 through 8.

Brake drum 206 is fabricated by compacting a sleeve 220 (FIG. 11) of ferrous powder blend in direct contact with back 210 and the inner cylindrical surface 213 of shell 208. FIG. 12 is a fragmentary vertical section illustrating the tool set and the actuators of a press such as might be used in compacting sleeve 220 (FIG. 11) directly within shell 208. An upper female die 230 is mounted on a die shoe 232 which is carried on a ram (not shown) of the press. Die 230 has a generally cylindrical cavity 234 conforming closely to the contour of shell 208 so that shell 208 is retained within cavity 234. A plurality of ejector pins 235 communicate with cavity 234. The lower tools include a two-piece die member having a confining ring 236 and an annular die 237. A cylindrical core 238 is spaced concentrically and radially inward of die 237 to form an annular receptacle 240 therebetween. Receptacle 240 is closed at its lower end by an annular punch 242. Die 237 has a radially inward cylindrical surface 241 in vertical alignment with the inner cylindrical surface 213 of shell 208. The radial thickness of receptacle 240 and punch 242 are substantially equal to the radial thickness of sleeve 220.

A plurality of compression springs 243 yieldably support ring 236 on a vertically movable platen 246. Die 237 is fixed on platen 246 so that ring 236 can be pushed downward relative to die 237 by die 230 to position the upper end 244 of die 237 in the outwardly flared portion 218 of shell 208. Platen 246 is in turn supported on a vertically movable platen 248 by a plurality of vertical rods 249. Platen 248 also supports core 238 through a vertical post 250, a vertically movable platen 252 and a power cylinder 254 having a fluid actuated piston 256 for moving core 238 upward with respect to platen 248 and die 237. Rods 249 and post 250 are vertically movable through suitably dimensioned apertures 260 in a stationary platen 262. Punch 242 is mounted directly to platen 262. Platen 248 is arranged to float with respect to platen 262 and punch 242. To this end a plurality of vertical rods 266 are secured in platen 2 48 and extend downward through openings 268 in a lower stationary platen 270. Compression springs 272 surrounding respective rods 266 engage the lower surface of platen 248 and the upper surface of platen 270 to urge platen 248 upward. Nuts 274 are threaded on the lower ends of rods 266 to engage platen 270 and thereby limit upward travel of platen 248. By this arrangement, platen 248 can be moved downward toward platen 270 against the action of springs 272 so that ring 236, die 237 and core 238 move downward relative to punch 242 which is stationary.

With the press open (FIG. 12), shell 208 may be inserted into die 230 and retained therein by friction or suitable holders (not shown). Receptacle 240 is then charged with a quantity of ferrous powder blend 280 sufficient to be compacted into a sleeve 220 (FIGS. 11 and 14) having a height equal to the height of shell 208. The compaction operation is initiated by lowering the ram (not shown) of the press which carries die 230 downward. Die 230 descends until it bottoms on ring 236 and continued downward movement of die 230 pushes ring 236 downward against the action of springs 243 until ring 236 bottoms on platen 246. Downward movement of ring 236 relative to platen 246 and die 237 positions the upper end 244 of die 237 in the outwardly flared portion 218 of shell 208. Simultaneously, core 238 may be moved upward by piston 256 into engagement with back 210. FIG. 13 shows the position of the dies after die 230 has bottomed on ring 236,

ring 236 has bottomed on platen 246, and core 238 has bottomed against back 210. The spacing between core 238 and the radially

inward surfaces

213 and 241 of shell 208 and end 244, respectively, forms an annular mold 284. As the ram continues downward, die 230 pushes ring 236, die 237 and core 238 downward relative to punch 242 which is stationary so that the powder 280 contained in receptacle 240 is compacted within mold 284 to form sleeve 220 in tight assembly with shell 208 (FIG. 14) Suitable stops are provided in the press to terminate the downward movement of the ram when punch 242 has formed sleeve 220 to the proper height. During the compacting operation, springs 272 are compressed to maintain ring 236, die 237 and core 238 engaged with die 230 and back 210, respectively. Die 230 is raised away from ring 236, die 237 and core 238 so that shell 208 having sleeve 220 therein may be ejected from die 230 by pins 235.

Shell 208 with sleeve 220 therein (FIG. 11) is then heated to sinter the ferrous powder as described in connection with FIGS. 1 through 6. The characteristics of powders 280 together with the conditions and variations during compacting and sintering also correspond to those previously described.

This invention also contemplates an apparatus for compacting a metal powder lining within any cavity having one end open and one end closed or substantially closed. FIG. 15 is a fragmentary view illustrating a cup-shaped shell 286 having a bottom 288 and cylindrical side wall 290. A sleeve 292 of metal powder may be compacted tightly within shell 286 in direct contact with the inner cylindrical surface 294 of side wall 290 by the methods hereinbefore disclosed. However, the shape of the cavity in the upper female die 230 must be modified to conform closely to the outer contour of shell 286 so that radial and longitudinal distortion of shell 286 is restrained during the compacting operation.

Although the apparatus (FIGS. 12 through 14) of the invention has been disclosed as having a core 238 which is moved upward with respect to ring 236 and die 237 by a piston 256, it is to be understood that a core similar to core 238 could be fixed relative to die 237 in a position extending above die 237 so that ring 236 would bottom on platen 246 at the same time that the core bottoms on back 210. Alternatively, core 238 could float with respect to ring 236 and die 237 so that after die 230 has bottomed on ring 236, and ring 236 has bottomed on platen 246, core 238 would remain vertically fixed until it bottomed on back 210 during the downward descent of die 230, die 237 and ring 236. In either situation, core 238 should be engaged with back 210 before any significant compacting of powder 280 occurs.

I claim:

1. Apparatus for use in making a brake drum having a sintered metal brake track by compacting metal powders in a cylindrical brake drum shell having one end open and the other end at least partially closed by a radially inwardly extending flange, comprising first and second vertically aligned and opposed die means, said first die means being spaced above said second die means to receive and retain said shell with the open end thereof facing downwardly toward said second die means, said second die means comprising an outer confining die means, a cylindrical core die and an annular punch, said outer confining die means having an inner cylindrical wall vertically aligned with the inner cylindrical surface of said shell, said core being spaced radially inwardly and concentrically of said wall on said confining die means to form a receptacle therebetween dimensioned to accommodate in the second die means a full charge of metal powders suflicient to form said track, said core having an outer peripheral surface corresponding to the inner peripheral surface of said brake track, said punch being positioned to close a lower end of said receptacle and mounted to move in the space between said core and said confining die, the upper end of said eptacle being open to receive said charge of metal wders, means for moving said first die means and said nfining die means into engagement with each other while d wall of the confining die means is vertically aligned th the inner peripheral surface of the shell, means for )ving said core into said shell to form an annular cylinical mold defined by said shell, said core and at least an nular zone of said flange, and means for moving said nch relative to said first die means so that said punch )ves toward said flange to transfer substantially all of said arge from said receptacle through said open upper end ereof and into said mold and to compact said metal )WdGlS into said mold in direct contact with said shell lCl. said flange.

2. The apparatus set forth in claim 1 wherein said inch is stationary, said outer confining die and said core "e mounted to float relative to said punch and said means Ir moving said punch causes the punch to move relave to said confining die means, said core and said first e means.

3. The apparatus set forth in claim 1 wherein said ange substantially closes said one end of said shell to )rm a drum back integral with said shell, said core die has top face dimensioned to abut a radial face on said drum ack and said means for positioning said core within said lell causes said top face on said core to abut said radial 166 on the drum back.

4. The apparatus set forth in claim 1 wherein said ange defines a circular aperture at said one end of said hell, said core and said aperture each having a diameter ubstantially equal to the inside diameter of said brake rack, said first die means has a bore therein communicatrlg with said cavity and registering with said aperture vhen said shell is retained in said first die means, and vherein said means for positioning said core within said hell is constructed to move said core into said shell and hrough said aperture into said bore in close-fitting relation said flange to form said mold.

5. An apparatus for use in making a brake drum having a. sintered metal brake track by compacting metal powders n a brake drum shell which has a generally cylindrical Jody portion, a radially inwardly extending flange at one end of said body portion and a circular aperture in said Flange, the other end of said body portion being open, comprising first and second vertically opposed die means, said first die means having a cavity therein which opens downwardly and is constructed to receive and retain said shell with the open end of said body portion facing downwardly toward said second die means, said first die means further having a bore communicating with said cavity and registering with said aperture when said shell is retained in said first die means, said second die means comprising outer confining die means, a cylindrical core die and an annular punch, said outer confining die means having an inner cylindrical wall vertically aligned with the inner cylindrical surface of said body portion, said core being spaced radially inwardly and concentrically of said wall of said confining die means to form a receptacle therebetween, said receptacle being open at its upper end to receive a charge of metal powders, said core and said aperture each having a diameter substantially equal to the inside diameter of said brake track, said punch being mounted in said lower die means to close the lower end of said receptacle and to move vertically in the space between said core and said confining die, said punch having a cross section which corresponds to the cross section of the brake track, means for moving said first die means and said confining die means into engagement with each other so that said wall of said confining die means is vertically aligned with the inner peripheral surface of said body portion, means for moving said core into said shell and through said aperture into said bore in close-fitting relation to said flange to form a brake track mold defined by said cylindrical body portion, said flange and said said punch relative to said first die means so that said punch moves toward said flange to transfer said metal powders from said receptacle and compact said powders into said mold in direct contact with said shell and said flange.

6. The apparatus set forth in claim 5 wherein said punch is stationary, said outer confining die and said core are mounted to float relative to said punch and said means for moving said punch causes the punch to move relative to said confining die means, said core and said first die means.

7. An apparatus for use in making a brake drum having a sintered metal brake track secured in a generally cylindrical brake drum shell, comprising a female die having a generally cylindrical cavity therein for receiving and retaining said shell, a core adapted to be positioned within said cavity in spaced concentric reation to said shell when said shell is retained in said cavity to thereby form an annular mold, a receptacle for containing a charge of metal powders, said receptacle having an opening therein adapted to register with said annular mold, and means for transferring said powders from said receptacle to said mold and for compacting said powders therein in direct contact with said shell and wherein said shell has a back portion substantially closing one end thereof, said back portion having a radial dimension substantially greater than the radial thickness of said track, and wherein said apparatus further comprises means for moving said core into said shell with a top face of said core abutting said back portion to form said mold.

8. An apparatus for use in making a brake drum having a sintered metal brake track secured in a generally cylindrical brake drum shell, comprising a female die having a generally cylindrical cavity therein for receiving and retaining said shell, a core adapted to be positioned within said cavity in spaced concentric relation to said shell when said shell is retained in said cavity to thereby form an annular mold, a receptacle for containing a charge of metal powders, said receptacle having an opening therein adapted to register with said annular mold, and means for transferring said powders from said receptacle to said mold and for compacting said powders therein in direct contact with said shell and wherein said shell has a radially inwardly extending flange at one end thereof defining a circular aperture at said one end, said core and aperture each having a diameter substantially equal to the inside diameter of said brake track, said female die has a bore therein communicating with said cavity and registering with said aperture when said shell is retained in said female die and means for moving said core into said shell and through said aperture into said bore in close-fitting relation to said flange to form said mold.

9. Apparatus for use in making a brake drum having a sintered metal brake track by compacting metal powders in a cylindrical brake drum shell having one end open, comprising first and second vertically aligned and opposed die means, said first die means being spaced above said second die means to receive and retain said shell with the open end thereof facing downwardly toward said second die means, said second die means comprising an outer confining die means, a cylindrical core die and an annular punch, said outer confining die means having an inner cylindrical wall vertically aligned with the inner cylindrical surface of said shell, said core being spaced radially inwardly and concentrically of said wall on said confining die means to form a receptacle therebetween dimensioned to accommodate in the second die means a full charge of metal powders suflicient to form said track, said core having an outer peripheral surface corresponding to the inner peripheral surface of said brake track, said punch being positioned to close a lower end of said receptacle and mounted to move in the space between said core and said confining die, the upper end of said receptacle being core, and means for moving open to receive said charge of metal powders, means for moving said first die means and said confining die means into engagement with each other while said wall of the confining die means is vertically aligned with the inner peripheral surface of the shell, means for moving said core into said shell to form an annular cylindrical mold between said shell and said core, and means for moving said punch relative to said first die means so that said punch moves toward said first die means to transfer substantially all of said charge from said receptacle through said open upper end thereof and into said mold and to compact said metal powders into said mold in direct contact with said shell.

References Cited UNITED STATES PATENTS Calkins et a1 75-208 X Hettel 25-103 X Tormyn 75-208 X Smith 18-16.5X Maritano 18-165 Van Bakel et a1 18-165 Wellman 75-208 US. Cl. X.R.