US594584A - Apparatus for forming sand molds - Google Patents

Description

2 Sheets Sheet 1.

(No Model.)

Patented'Nov. 30,1897.

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APPARATUS FOR FORMING SAND MULDS. No. 594,684.

Patented Nov. 30, 1897.

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NITED STATES PATENT EEicE,

STEPHEN JARVIS ADAMS, OF PITTSBURG, PENNSYLVANIA.

APPARATUS FOR FORMING SAND MOLDS.

SPECIFICATION forming part of Letters Patent No. 594,584, dated November 30, 1897. Application filed March 21, 1895. Serial No. 542,615. (No model.)

To all whom it may concern.-

Be it known that I, STEPHEN JARVIS ADAMS, a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented anew and useful Improvement in Ap paratus for Forming Sand Molds; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to the making of sand molds, and relates more particularly to the compacting of sand molds by moving the pattern and its stripping-plate in such manner as to compress the same.

The invention relates generally to the same class of mold-making as described in an application filed by me May 11,1894, Serial No. 510,846, which described the mechanism for confining the sand within the flask and forcing the pattern upwardly into the body of sand, so as to compact it, that invention being illustrated more particularly in connection with the making of molds for brakeshoes and the formation of both mold-faces at the one operation, and though this invention is not illustrated for the making of the same class of molds and is not confined to the same it is well adapted for the purpose. In the pressing of sand molds Where the mold has considerable depth of wall around its mold-cavity-that is, a considerable body of sand to compact toform the side walls of the mold-cavityi'n order to bring the body of sand to the proper degree of compactness it is necessary that this part of the mold ,be compacted with a longer stroke than the thinner part of the mold, such asthatabove the.

mold-cavity, the custom has been to move the two pressing parts separatelyfor example, either to first advance the pattern and then the pattern-plate, or to first advance the pat-' tern-plate and then the pattern, or to advance them so that they reach their final positions at different times. In such methods of pressing it has been found that the union between the two bodies of sandnamely, that compressed by the pattern and that compressed by the plate-is strained and insome cases is broken by a shearing action between the two bodies of sand, which leads to the breaking of the ,mold when the pattern is withdrawn or afterward, because there is not sufficient hold or bond between the sand above parts for forming the same, and, though the custom has been to make the pattern in one piece, if the movement as heretofore applied to pattern and pattern-plate were applied to respective pattern parts the same difficulties would be encountered, while where the patternis made in a single piece, as at present practiced, there cannot be the even compacting of the sand above the respective parts of the pattern which is desirable, while in pressing molds it is practically impossible tovary the amount of pressure in compacting any particular part thereof, which is often desirable for venting and other purposes. I have discovered that by giving to the pattern-plate and to the respective pattern parts a different movement in the compacting of the sand these difficulties may be overcome; and my invention, which relates to this subject, comprises, generally stated, an apparatus for forming such molds in which the sand is filled over the pattern-plate and respective pattern parts and compressed by different compressing strokes of the plate and the respective pattern parts, said strokes traveling regularly together, but at diiferent speeds, and stop- :ping at the same time, so that the desired compressing action can be obtained in any part of the mold-body whether it requires a long or a short stroke, and yet, as all are moving regularly together, the sand is so compacted that each body or portion is moving with the body next to it and the shearing action above referred to does not occur, and therefore a much more homogeneous and a stronger mold is produced.

To enable others skilled in the artto practice my invention, I will describe the same more fully, referring to the accompanying drawings, in which- Figure 'l is a vertical cross-section of a sand mold ill ustrating my invention, the parts being in position to receive the sand and the eam-yokes being omitted, so that the shapes of the cams may more clearly appear; and Fig. 2 is a longitudinal vertical section showing the finished position of the parts when the mold is completed.

Like letters indicate like parts in each of the figures.

The mold illustrated in the drawings might be termed an ideal mold, illustrating the principle to be carried out, which when understood can be applied to practically all molding apparatus acting to compress the sand by regular pressing strokes.

The apparatus has the table A, supported on suitable iron frames, between which extend one or more cross-beams (1,, which also act as guides for the cam-bars. On the table is the llask-supporting plate I), on which the flask c rests, said plate I) being guided to place by any suitable lips or lugs c, the plate Z) having a central opening the inner faces of which correspond to the inner-faces of the flask, and depending from the plate around such opening the llange 0 which forms a pocket (I of the desired depth below the flask, into which the sand above the stripping-plate enters. Fitting within said pocket is the pattern F, the pattern forming the inner wall of the pocket:- (I, while the stri 'ming or pattern plate y forms the base thereof. Extcnd ing over the top of the flask c is a confiningplatc E, which is held to place during the pressing operation by any suitable means. In the pattern shown in the drawings I have illustrated three di Il'erentpattern parts,these parts being separate from each other and being marked f, and f For the purposes of the ease the pattern parts ff may be considered annular. The said several pattern parts are, as shown by the drawings, of different heights and extend up within the flask for different heights before the compressing action takes place, while their stroke to linished position is illustrated by dotted lines in Fig. 1 and shown in full lines in Fig. 2.

The principle on which the pattern and the strippingplate are arranged will now be stated. Molding sand requires a certain amount of compression to bring itfrom its mealy unpacked condition to about the proper compactness for retaining the metal and yet permit the escape of the gases through the body of sand, that compression being about one-third of the original body of sand, or to two-thirds of its original bulk. The pattern parts are therefore so arranged that the stroke of each respective part will be sufficient to give this compression to the sand above it, and therefore the higher pattern part will have a shorter stroke as compared with the lower pattern part, and so on through any number employed, while the stripping-plate will have the longest stroke of all. As it is always dosirable that the sand around the mold-cavity and forming the side walls thereof be compacted more than that above the same forming the end wall thereof, the stripping-plate is required to have a somewhat longer stroke than the others in proportion to the body of sand to be compacted, so to pack the sand above it harder than that above the pattern proper. The pattern and the stripping-plate illustrated in the drawings are arranged on this principle, and the respective strokes of the same are illustrated by the dotted lines above the stripping-plate and pattern parts. For imparting these strokes to the different parts any suitable mechanism may be cmployed,that illustrated in the drawings being, so far as the apparatus is concerned, substantially the same as thatin the application above referred to and being well suited for the purpose. The stripping-plate g is supported on a skeleton frame 1 by means of blocks at the ends thereof, and the cam-bars 1 operating the plate,arc connected to said skeleton frame g and extend down through guideways on the cross-beams (1 In like manner the outer pattern part 1" is connected to a skeleton frame 76, from which cam-bars 7t depend, moving in guides 7L2 on the cross-beams a, and the pattern partfis supported by a like frame 1', from which cam-bars it depend and pass through bearings t in the cross-beams. The central pattern part 1 can be provided with a like frame,but it is generally only found necessary that such a part have its cam-bar 7.: connected directlyto it, the cam-bar passing through guideways 7.3 in the cross-beams. The pattern parts can be thus arranged together according to the number of pattern parts having the different movements, and therefore the number to have different frames.

Extending below the line of cam-bars is the cam-shaft m, which carries a series of cams or eccentrics, all of which are arranged to give the necessary movements to the several bars. For example, the cam-bars are operated by the cams the cam-bars h are operated by the cams la, the cambars are operated by the cams t, and the central cambar 7; is operated by the cam it". The arrangement of these cams with relation to each other is shown in Fig. 2, the cams having such throw as to give the necessary stroke to the stripping-plate and pattern parts, the cams, as shown, being so constructed that the movements of the several parts commence together and proceed by regularstrokcs, but at different speeds, according to the lengths of the strokes, and reach the ends of their strokes at the same timcthat is to say, that the stripping-plate and pattern or its parts are mov ing regularly upward at the same time and reach their final positions at the same time and proceed with regular strokes, according to their respective lengths of strokes between said positions. Indeed, the operating pressing-faces of the cams for these strokes are preferably simple eccentric faces, and except and enabling it to travel in true vertical line.

above the patterns and the stripping-plate,

that a more rapid withdrawal of the patterns is desired simple eccentrics of different throws might be employed.

In the operation of the apparatus, as the cams are traveling always in one direction, the friction on the bases of the cam-bars causes them to press and wear on one side of the lower bearings more than on the other, which by' enlarging the lower bearings permits the lower ends of the cam-bars to swing laterally and cause a like side movement of the patterns at the other ends thereof. This causes the binding and wear of the patterns and in the end affects the molds formed thereby. To overcome this difficulty, as shown in Fig. 1, I secure to each cam-bar below its bottom guide-bearing an arm 19, carrying a roller 19, which travels over a vertical guide 0", secured to the machine-frame, so sustaining the lower end of the cam-bar against the lateral strain The guide 0" may be made adjustable, such as by means of set-screws r, passing through the bracket o supporting the guide.

Though the above apparatus may be varied in construction, it well illustrates the principle of the invention desired to be covered, and I will now describe the operation in connection therewith. The patterns being in their lowest position, as shown in Fig. 1, sand is filled within the flask, and after the striking off of the sand the confining-plate E is placed thereon and secured in position. It will be noticed that the sand fills the space and for the patterns to reach their respective final positions, as illustrated by dotted lines in Fig. l and full lines in Fig. 2, each has a stroke for about one-third the thickness of the body of sand aboveit, the stripping-plate, however, having alittle longer stroke to compact the sand above it somewhat harder than the rest of the sand, for the reasons above stated. The apparatus is then started and the stripping-plate and the respective pattern parts move at regular speeds upwardly and end their upward strokes at the same time, and such upward strokes are preferably regulated at different respective speeds, according 1 to the required travel of each pattern part. As a result of such movement of the parts all of the sand is under compressing action at the same time, and its particles are all acted upon in such way that they move into each other and unite to form a proper bond between the respective parts above the different patterns, because they are all under mold evenly compacted and yet practically' homogeneous throughout. In this way another important advantage can be obtained namely, that the amount of compression imparted to the different bodies of sand can be accurately determined, depending upon the throw of the particular pattern part operating on the same or the adjustment of the pattern; and the skilled constructor can easily form an apparatus which will give the desired packing of sand in any part of the mold through the application of the principles thus illustrated.

What I claim as my invention, and desire to secure by Letters Patent, is

In sand molding apparatus for forming molds having different depths in the moldcavity, the combination of a pressing-pattern composed of several independent upwardlymovable pattern parts of different height, and a series of cams operating on the respective pattern parts, and having different lengths of strokes respectively and set so that their pressing action will commence at the same time and end at the same time, substantially as set forth.

In testimony whereof I, the said STEPHEN JARvIs ADAMS, have hereunto set my hand.

STEPHEN JARVIS ADAMS.

Witnesses:

J. M. BOSSERT, ROBERT C. TOTTEN.

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