US1779763A - Apparatus fob and method of fobming castings - Google Patents

Description

Oct. 28, 1930. H. c. CARTER ET AL APPARATUS FOR AND METHOD OF FORMING CASTINGS Filed April 25, 1929 2 Sheets-Sheet l FIT l .llllllll.w lllllll 1 TTUFQNE/ H. c. CARTER ET L 1,779,763

APPARATUS FOR AND METHOD OF FORMING CASTINGS Filed April 23, 1929 2 Sheets-Sheet 2 5 Fry. /5

/NL/E/\/ THEE HLCARTER & H.EI.5PIETH E w flTTU/ NE/ Patented Oct. 28, 193% PA TE N orrlca HASKELL C. CARTER AND HARRY E. SIE'IETHI, F PORTLAND, OREGON, ASSIGNOBS 'I'O IRON FIREMAN MANUFACTURING COMPANY, OF PORTLAND, OREGON Application filed April 23,

This invention relates generally to the Y foundrymens art, and especially to the casting of steel helical conveyers.

The main object of this invention is to provide a method of and apparatus for forming molds in which may be cast helical objects.

The second object is to so form the molds that the riser castings will not show a parting line or any undue roughness which must oth-, erwise be removed by expensive grinding operations.

The third object is to reduce to a minimum the losses occasioned by imperfect castings and the necessity of repairing molds made in the'ordinary manner before a casting can be made from same. I

The fourth object is to make it possible to form a mold by this process in a fraction of the time required under existing methods.

The fifth object is to make it possible to se-' cure a high grade of workmanship from workmen having only a fair amount of skill. V

These, and other objects, will become more apparent from the specification following as illustrated in the accompanying drawings, in which a Figure 1 is a side elevation of a typical form of helical conveyer pattern with the midsection brokenaway for shortening puroses. 1 I Figure 2 is an end elevation of the stripper ox.

Figure 3 is a longitudinal section through the stripper box.

Figure 4 is a perspective View of a flask.

Figure 5 is a perspective View of the pattern supporting box.

FigureG is a perspective view of the flask cover. y

Figure 7 is a perspective view of the core for forming the end of the mold.

Figure 8-is a longitudinal section through the mold showing the sand being packed around the pattern.

Figure 9 is a transverse section taken along the line 99 in Figure 8. I

Figure 10 is a view similar to Figure 9 but showing the flask inverted and the pattern supporting box removed.

1929. Serial N0. 857,406.

Figure llshows the pattern being withdrawn from the mold.

Figure 12 is a side elevation of the mold with the end portions broken away to disclose the riser and showing the core block in position.- I

Figure 13 is a fragmentary side elevation of a perfect helix;

Figure 14 is a section taken along the line I 14 -14 in Figure 13 showing the smooth lines of a screw, cast by this method.

Figure 15 is a similar view taken through a worm by the ordinary split mold showing the fins and uneven parting lines, taken along the line,l515 in Figure 16.-

Figure 16 is a fragmentary side elevation of the worm cast imperfectly as in Figure 15.

. 7 Similar numbers of reference refer to similar parts throughout the several views.

Referring in detail to the drawings, in Figure 1 there is shown a pattern for a representative form of screw 'conveyer consisting of a helix 20 formed on a stem 21 having a projecting end 22 at one end thereof and another projecting end 23 at the opposite end thereof which is preferably provided with a flattened portion 24 to which may be attached a pneumatic vibrator 25 for rapping purposes.

There is also shown a flask consisting of the handled sides 26, a closed end 27 and an end 28 which is provided with an opening 29,v on

the upper and lower sides of which are formed the loops or straps 30 for the insertion of wedges 31. There is also shown a flask cover 32 similar to those now in-use. Upon the flask cover 32 is placed a pattern-supporting V- shaped box 33 which is held upright by the blocks 34. Toward one end of the flask cover 32 (that is nearest the closed end 27 of the flask) are formed the dowel holes 35 which receive-the dowel pins 36 of the-supporting member 3'7 whose rounded end 38 is provided 39 which receives the end 22 withan' opening of the stem'21. I I

On the, fl 'sk cover 32 is placed a stripper box 40 whose ends 41 and 42 are provided with slots 43 adaptedto receive the helix 20 of" the pattern." One side of each slot 43 is provided with a scraping edge 44 which pre- Vents loose sand from, clinging to thepattern and becoming deposited within the box 40. The box 40 has been introduced through the opening 29 and is prevented from escaping from same by the wedges 31.

. The function ofthe box 40 and its end 41 (which in this instance is the end touchingthe sand of the mold) is to serve as a stripper when the pattern is withdrawn longitudinally from the mold.

In Figure 12 is illustrated a core block 45 which is substituted for the stripper box 40 after the pattern is removed, and in the same view is also shown a riser core 46 which is introduced after the member 37 is withdrawn. There is also illustrated the usual form of pouring cup 47 which communicates with the riser core 46.

In Figure 12 it can be seen that the long end 23 of the pattern stem 21 is replaced by a sguare shouldered end 48 by the substitution 0 the core block 45.

The method of forming castings by the use of the apparatus thus far described is as follows: Upon the flask cover 32 is placed the flask and within same is placed the pattern supporting box 33 and the supporting member 37. The pattern itself, which is preferably of aluminum and carefully machined to a true helix, is now putinto place through the opening 29, after which the stripper box 40 is threaded upon the end of the helix and the pattern is pushed into the flask to the proper position and the wedges 31 are put into place to prevent the subsequent tamping of the sand 49 from pushing it outwardly.

It will be seen in Figure 9 that the outer portion of the helix 20 rests upon the supporting box 33. Sand 49 is now carefully tamped around the upper side of the pattern (as shown in Figure 8) which operation is continued until the top side of the flask is completely filled. A second cover 32 is then clamped on top of the flask which is then inverted to the position shown in Figure 10, after which the first cover 32 is removed and then the box 33 is removed exposing a portion of the helix 20 of the pattern. Sand is then carefully packed around the exposed parts, after which the flask is completely filled and tamped.

The next operation, namely that of removing the pattern from the mold, (which has always been a diflicult task) is performed by fastening the pneumatic vibrator 25 to the flattened end 24 of the pattern stem 21 and imparting a vibrating action to the pattern, which actually causes the pattern to rotate and emerge from the mold in most instances, although sometimes it is desirable to assist this action by a slight pull on the protruding end 22 of the pattern.

After the pattern is removed the stripper box 40 is withdrawn and the core block 45 substituted therefor and locked in place by means of the wedges 31. In place ofthe supporting member 37, which is now also withdrawn, there is substituted a riser core 46 above which is formed the pouring cup 47. The casting 50 which in this instance is of steel, may now be poured in the usual manner. Naturall when steel castings are made it is desirab e to employ special sand for immediate contact with the molten metal, as is commonly understood. The resulting casting 50 will be found to be as truly helical as is the pattern from which the mold is made, the outermost portion thereof being cylindrical and the flights themselves being perfectly continuous instead of offset, as is ordinarily the case with split molds, as illustrated in Figures 15 and 16.

By this method it is possible to not only economize greatly-on the time consumed, but there is an appreciable increase in the number of perfect castings produced and a decided decrease in the number of unusable castings produced as compared with existing is nothing else than an air hammer and that the inertia thereof is suflicient to cause an unbalanced vibratory action, causing the blow gitudinally for the purpose-of rotating same while removing same spirally from said sand.

2. A method of forming molds for steel Worms consisting of placing the pattern in a flask and completely surrounding same with sand, then subjecting said pattern to a vibratory action for the purpose of spirally withdrawing said pattern from the mold, and then closing the open end of said mold from which said pattern has been withdrawn.

3. A method of forming helical conveyers consisting of supporting the pattern therefor in a fla'sk, a core print forming a support for one endof said pattern and a stripper box forming a support for the opposite end of said pattern, then tamping sand all around said pattern and on both sides of said core print, then spirally rotating said pattern for the urpose of withdrawing same from the mold, then replacing said stripper box with a core block for the purpose of closingthe end of v for said core print.

' to rest uponthe lowermost cover,a core print the mold from which the pattern has been pose of Scraping any molding sand that may withdrawn, and then substituting a riser core cling to the pattern from same and prevent- 4. A method of forming steel worms consisting of tamping sand completely. around the pattern of said worm, then drawing said pattern through a stripper box which temporarily forms the end of the mold by means of a longitudinal, unbalanced, vibratory action, and then closing said mold by substituting a core block for said stripper box;

5. A method of forming steel worms consisting of tamping sand around one side of the worm pattern, then inverting said pattern and tamping sand around the remaining side 7 thereof, then removing the pattern from the mold by means of a vibratory action parallel with the axis of the pattern provlding a spiral movement, andthen closing the end of-the mold from which the pattern hasbeen made and forming a riser at the opposite end 7 thereof.

consisting of a flask having'an opening at one end thereof, a cover for each side of'said flask, a V-shaped pattern supporting box adapted at one end of said V-shaped box forming a support for one endof the pattern, a stripper box at the opposite end of said V-shaped support forming a support for the opposite end of said pattern, a core block for replacing said stripper box, a riser core for replacing said core print, and means for drawing a patof saidtern through said stripper box out mold.

7. In a mold the combinationofaflongiing its entry int tudinal flask member having a pair of closed sides and one closed end and having a pair? open sides and one end having an openi g formed therein through which a stripper box can be passed, a stripper-box adapted to be passed through said last mentioned end, said stripper box having slots formed therein through which a helical pattern can be passed, a flask cover upon which said flask rests, a core print mounted on said cover opposite said stripper box, a V-shaped pattern supporting box mounted on said flask cover between said stripper box and core print, means for vibrating said pattern to assist in the withdrawal of same, a core block which may be substituted for said stripper box, a riser core which may be substituted for said core print, and means for inverting said-mold for the purpose of removing said pattern sup porting box and completely filling and tamping said flask.

8. A strip r box for molding steel worms consisting o a box-like structure having slots 0 said stripper box. HASKELL C. CARTER. HARRY E, SPIETH.

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