US2076790A - Method of molding - Google Patents

Description

April 13, 1937. H. B. MYERS 2,076,790

METHOD OF' MOLDING Filed July 1, 1955 ATTORNEYS Patented Apr. 13, 1937 PATENT OFFICE METHOD OF MOLDING Henry B. Myers, Cleveland Heights, Ohio, assignor to The Ferro Machine & Foundry Company, Cleveland, Ohio, a corporation of Ohio Application July 1, 1935, Serial No. 29,231

1 Claim.

This invention relates to the art of molding, and more p-articularly to a novel method and apparatus for forming sand molds for the production of cast metal articles.

More specifically, this invention has to do with a novel method and apparatus for forming green sand molds, having one or more undercut recesses or grooves in a Wall thereof, for the production of cast metal articles having one or more corresponding projections thereon such as brake drums having annula'rly extending ridges or iins. Heretofore cast metal brake drums of this form have been provided with the desired ridges or fins by machining grooves in an annular surface of the l5 drum to leave such ribs or fins upstanding. Such machining of the cast metall brake drums has involved considerable additional expense. By my novel method and apparatus, as will be explained more fully hereinafter, the sand mold is formed with one or more undercut recesses or grooves in a wall thereof whereby the desired ridges or ns are cast integral on the surface of the brake drum.

It is therefore an object of the present invention to provide a novel method of molding wherein the cavity of a green sand mold is extended by forming an undercut recess in a wall thereof.

Another object of the invention is to provide a novel method of molding involving the forming of a green sand mold with a cavity therein having substantially the shape of the body of the casting desired, and forming one or more undercut recesses or grooves in-a wall of the cavity to provide the same with extensions corresponding with projections or ns desired on the casting.

Still another object of this invention is to provide a novel method of molding wherein the forming of the undercut grooves or recesses is accomplished by rolling.

A further object of this invention is to provide novel molding apparatus embodying a ridged roller and means for causing relative traversing movement between the roller and a wall of the cavity of a sand mold.

Still another object of this invention is to provide novel molding apparatus, of the type referred to, embodying means for eccentrically mounting the ridged roller.

Other objects and advantages of the invention will be apparent from the following description when taken in conjunction with the accompanying sheet of drawings, wherein Fig. l is a top plan View of molding apparatus embodying my invention.

Fig. 2 is a transverse sectional view thereof taken on line 2-2 of Fig. 1. c

Fig. 3 is a partial transverse sectional view showing the shape of the mold cavity prior to the forming of the vgrooves or recesses in the wall thereof, and

Fig. 4 is a partial transverse sectional view taken through a ribbed brake drum produced by a mold formed according to my invention.

More detailed reference will now be made to the accompanying drawing for the purposeA of describing my novel method and apparatus for making vsand molds. It will be understood, of course, that the apparatus shown in the drawing is to be regarded as illustrative only and that it is subject to variation within the scope of .the appended claim.

In accordance with my novel method, as will be explained more in detail hereinafter, I form a green sand mold with a cavity therein corresponding in shape substantially with the body of the metal article to be cast, and then form one or more recesses, for example grooves or the like, in a side wall of the recess to correspond with projections or fins desired on the article. the recesses or grooves may be formed in the wall of the mold cavity in various ways, my invention contemplates the forming of these grooves by a rolling operation whereby the grooves are formed by pressing the ridges of a ridged roller into the sand of the mold as relative traversing movement takes place between the roller and the mold.

In Figs. 1 and 2 of the drawing I show novel apparatus for carrying out my method, although it should be understood that the method can be practiced with the' aid of various other kinds of apparatus or machinery. As shown in the drawing, my novel apparatus includes a support I0 which is preferably in the form of a metal plate adapted to rest upon the mold box or section II containing the green sand I2 in which the mold cavity I3 is formed. The plate support III may be provided with laterally extending ears I4 corresponding with the ears I4 of the mold section II and having openings I5 in which the dowel pins I6 engage. A roller I8 projects from the underside of the plate support I0 and is adapted to extend into the cavity or recess I3 of the mold when the support rests upon the section I I in the position shown in Fig. 2 of the drawing.

The roller I8 may be formed of metal, or any other suitable material, and has on its outer periphery a plurality of angularly extending ridges or fins 20 corresponding in number, size and cross sectional shape with the ridges or fms desired..

Although' on the cast metal articles to be produced. The ridges or fins may be formed on the roller by machining grooves 2li in the face thereof. The roller I8 cooperates with the side wall 22 of the mold cavity to form a plurality of undercut grooves or recesses 23 in the cavity wall. I find that best results are obtained when the roller I8 is of relatively large diametenand although the size of the roller may be varied somewhat, it may have a diameter as' great, or greater than, the semi-diameter of the mold cavity in which the roller is to operate. Y

For operatively mounting the roller I8 on the plate support I0, I provide the latter with a swinging arm 25 which carries the roller. The arm 25 may be mounted for swinging or rotary movementV relative to the plate support I0 by providing the arm with a shaftor spindle V26 which is rotatable in and extends through a.V

bearing 21 provided on the support. The free end of the arm 25 is provided with aboss or enlargement 28 in which a spindle 29 is rotatably mounted. This spindle projects outwardly from opposite sides of the boss V28 and the projecting be interposed between the eccentric portion 30 A Vand the roller I8. Y

Y VThe gear 32 of the spindle 29 meshes with a vrelatively stationary gear 36 whichzis connected to the plate support I0 by means of screws 31. The gear 36 has an opening therethrough aligned 40 with the bearing opening 2'I so asto accommodate Ythe shaft 26; The Shaft 26 jmaybel prevented 'frorn'dropping downwardly in the.l bearingj21 by means of a collar 38, which is secured to the shaft above the plate support I0 and serves as a thrust bearing. A "hollow cover 39-'may be secured Yto the plate support IU aroundthe thrust bearingv collar 38 to protect the same and to excludesand and other foreign matterrtherefrorn. i

The shaft 26 may be rotatedby any suitable power means, for example by means of the hand lever or crank 40 connected to theU outer end thereofi t Y i From the arrangementgjust described it will be seen that when the crank 40 is rotatedV the shaft 26 will cause the arm 25 to sweep around beneath the plate support I0 and causefthe spindle 29 to revolve around the xed gear 36. Since Vthe gear 32 of the spindle meshes with the fixed gear 36 it will be seen that such revolving of the Vspindle Vwill cause the spindle to rotate in the boss 28 of the arm 25. rI'he revolving offthearm 25 causes the roller I8 to be moved around the wallof the mold cavity, and thefrotation of the 1spindle29 and its eccentric portion 30 causes the roller to be alternately pressed against and moved away from the face of the side wall of the mold cavity. The alternate moving of the roller against and yaway from the side wall of the mold cavity by the eccentric portion 30 as the roller is swung around within the cavity causes the ridges 20 of the roller to press or cut into the sand of the mold with a sweepingf'or slicking action to form the grooves or Yrecesses 23'therein.

The gears 32 and 36 are Yso designed that the relatively fixed gear 36 is of larger pitch dialneter and has a greater number of teeth than the gear 32. Because of the larger number of teeth of the xed gear 36 the revolving of the arm 25 will cause the spindle 29 to rotate somewhat more than two turns during one revolution of the arm 25.' Hence by revolving the crank 40 a suflicient number of times the roller I8 will be pressed against the entire perimeter of the side wall of the mold cavity and will form continuous grooves 23 of the desired crosstsectional shape and depth therein.

In Fig. 4 of Vthe drawing I have shown, by way of example, a cross section through the rim part of a cast metal brake drum 4I havingaY generally cylindrical body portion 4I withv annular ridges or fins 4I thereon. In carrying out my novel methodof making sand molds for producing the brake drums 4I or likeA articles, a mold cavity is first formed. in the mold section II by packing the sandl I2 around a pattern which corresponds` in shape with the cylindrical body portion of the `metal article to be producedY The withdrawing of the pattern from the packed sand` Il and the roller will enter the mold cavity' I3 without scraping'against the side wall thereof.'`

After the plate support has been `thus applied to pins I6 engaging in the openings I5, the Vcrank 40 is revolved to cause the rolle! I8'totraverse the side wall 22 ofthe mold cavity and form. the grooves 23 therein in the manner explained above. After the grooves have been rolled into the wall of the mold cavity the eccentric portion 30 is again brought to a position from that shown in the mold section I I and positioned thereon by the Fig. 2 to disengage the ridges 20 of thevroller from the grooves which have been formed in the cavitywall. The plate support I0 can thenl be lifted from the mold section and the roller I8 therebywithdrawn from the mold cavity without damaging the grooves which have been yformed inV the cavity wall. n t

To facilitate the use ofthe apparatus it may be desirable to provide indicating means for visibly indicatingvto ythe operator the position of the-ec'-V i centric portion 30 of the spindle 29. For this purpose I may provide on the shaft 26 a gearr42 of the same pitch diameter as the relativelyfixed gear 36. 'I'he gear 42 drives a gear 43 which is of the same pitch diameter as the gear 372. The gear 43 carries an indication, such as a mark or projecting pin 44, which is located on the gear to correspond with the angular position of the offset portion of the eccentric 30. A fixed 'reference mark, such as a pointerr45, may be locatedadjacent the gear 43. I'he gear 43 and the pointer 45 may be conveniently mountedV upon a. lug or projection 46 extending above the plate support I0.

When the pin 44 registers with the pointer 45 the Y the Wall of the mold cavity. When the pin 44 f moves to a position diametrically opposite the pointer the operator knows that the roller has been disengaged from the cavity wall and canbe Withdrawn from the mold Without damage thereto.

To protect and support the upper edge of the mold cavity during the rolling operation I may provide the plate support Ill with a ring 48 on the underside thereof which has a contact face for engagement with the sand, corresponding in shape with the contour already given to the sand by the pattern around Which the sand Was packed. Similarly, the bottom Wall of the mold cavity may be protected during the rolling operation by a removable plate 49 applied thereto. As shown in Fig. 2, the roller I8 is in close running cooperation with the ring 48 and the plate 49.

l5 If desired, the plate support I0 may be provided with one or more threaded openings 50 to receive lifting devices, such as screw-eyes, to facilitate the handling of the apparatus and the application of the same to the mold sections I I.

20 From the foregoing description and the accompanying drawing it will now be readily seen that I have provided a novel method of forming green sand molds for the production of cast metal articles having projections thereon such as brake 25 drums having annular ridges or fins. It will be understood further that by my novel method undercut recesses or grooves corresponding With the projections or ridges of the article are formed in a side wall of the mold cavity by a rolling operation Whereby the ridges of a ridged roll are pressed into the sand. It Will also be readily understood that I have provided novel apparatus for forming undercut recesses or grooves in a Wall of green sand molds whereby articles having pro-v jections or fins thereon can be produced more economically than has been possible heretofore by machining the casting.

While I have disclosed the novel method and apparatus of my invention in a somewhat detailed manner, it will be understood, of course, that I do not Wish to be limited to the precise steps of procedure and details of construction herein described, but regard my invention as including such changes and modifications as do not constitute a departure from the spirit of the invention and the scope of the appended claim.

Having thus described my invention, I claim:

'Ihe method of molding which comprises forming a green sand mold having a substantially cylindrical recess therein, and then swinging a ridged roller around in the recess and alternately moving the roller against and away from the Wall of the recess during such swinging and thereby causing the ridges of the roller to be pressed into the Wall with a gyratory slicking action.

HENRY B. MYERS.

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