US3165794A

US3165794A - Apparatus for forming foundry molds

Info

Publication number: US3165794A
Application number: US118001A
Authority: US
Inventors: Loyal L Johnston
Original assignee: Herman Pneumatic Machine Co
Current assignee: Herman Pneumatic Machine Co
Priority date: 1961-06-19
Filing date: 1961-06-19
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19

Description

Jan. 19, 1965 5 Sheets-Sheet l Fi] .ed June 19, 1961 ig. l.

INVENTOR.

his ATTQRNEYS Jan. 19, 1965 L. L. JOHNSTON 3,165,794

APPARATUS FOR FORMING FOUNDRY MOLDS Filed June 19, 1961 5 Sheets-Sheet 2 INVENTOR.

LOYAL L. JOHNSTON his ATTORNEYS Jan. 19, 1965 L. JOHNSTON 3,165,794

" APPARATUS FOR FORMING FOUNDRY MOLDS Filed June 19, 1961 5 Sheets-Sheet 3 Fig.3.

\ 3 i INVENTOR. R LOYAL L. JOHNSTON BY his ATTORNEYS Jan. 19, 1965 L. JOHNSTON 3,165,794

APPARATUS FOR FORMING FOUNDRY MOLDS Filed June 19, 1981 5 Sheets-Sheet 4 Fig. 4.

Ilc

INVENTOR.

LOYAL L. JOHNSTON his ATTORNEYS Jan. 19, 1965 JOHNSTON APPARATUS FOR FORMING FOUNDRY MOLDS 5 Sheets-Sheet 5 Filed June 19, 1961 Fig.5.

INVENTOR.

LOYAL L. JOHNSTON his ATTORNEYS United States Patent 3,165,794 APPARATUS FUR FGRMING FOUNDRY MOLDS Loyal L. .iohnston, Zelienople, Pa., assignor to Herman Pneumatic Machine Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed June 19, 1961, Ser. No. 118,901 1 Claim. (Ci. 22-17) This invention relates to apparatus for forming foundry molds. .It relates more particularly to apparatus for forming foundry molds adapted for the centrifugal casting of elongated hollow articles such as pipe.

My Patents Nos. 2,449,900 and 2,559,161 disclose a method and apparatus for forming molds for centrifugal casting and centrifugally casting elongated hollow articles in such molds. Those patents contemplate the formation of a mold and'the centrifugal casting of an elongated hollow article therein at a single station, i.e., by the use of a duplex apparatus in which both the mold is formed and the centrifugal casting in the mold is carried out.

The method and apparatus of my above mentioned patents have proved highly successful and a large proportion of the cast iron soil pipe made in the United States and Canada is made on such apparatus by the use of such method. However the apparatus is relatively costly. Also, soil pipe is now in demand in ten foot lengths instead of the five foot lengths in which soil pipe was made substantially exclusively a few years ago. The building of an apparatus such as that disclosed in my above mentioned patents for the centrifugal casting of ten foot lengths of pipe would further greatly increase the cost of the apparatus.

I have devised comparatively simple and inexpensive apparatus for forming foundry molds adapted for the centrifugal casting of elongated hollow articles. My apparatus is Well adapted for the formation of long lengths of pipe, i.e., lengths of ten feet and longer. Also my apparatus is equally well adapted for the formation of molds for the centrifugal casting of soil pipe and pressure pipe. My apparatus may be rapidly and expeditiously adapted for the formation of molds for the centrifugal casting of elongated hollow articles of different lengths and diameters.

I form a mold out of finely divided mold forming material in a flask by apparatus quite different than that specifically disclosed in my above mentioned patents and I provide for removal of the mold to a separate station for casting instead of performing the mold forming and casting steps at the same station. I form the mold with the flask disposed generally upright rather than with its axis generally horizontal as in my above mentioned patents. The mold i formed and the finely divided mold forming material is compacted while the flask is stationary in cont-radistinction to the apparatus of my above mentioned patents in which the flask is rotated while the mold is being formed and the mold forming material compacted. I find that by use of my present apparatus I can form .a mold of high and uniform quality which produces superior centrifugally cast pipe, either soil pipe or pressure pipe. V

In use of my apparatus in forming a mold I fill the flask with finely divided mold forming material and form a cavity through the mold forming material and compact the mold forming material to the optimum extent for casting by forcing a former through the mold forming material 'm-the flask. The extent to which the mold forming material is compacted is determined'at least partially by the relationship between the external transverse dimension of the former and the internal transverse dimension of the flask. Formers of different trans- 3,165,794 Patented .Ian. 19, 1965;

V vision being made for changing formers without necessarily changing flask size. However, changes in flask size may also be made easily and quickly.

Also, molds of different sizes may be made in the same flask with the mold forming material compacted to optimum extent by providing for removal from the flask during formation of the mold of some of the mold forming material initially introduced 'into the flask.

Still further, additional compacting force maybe exerted on the mold forming material in the flask atone or *both ends of the incipient mold by auxiliary com verse dimension may be used with the same flask, pro- 7 e 7 ends.

pacting means. Any tendency for the mold forming material at either end of the flask to be less tightly compacted than the mold forming material at the mid portion of the flask may thus be overcome.

I provide apparatus for forming a foundry mold comprising an elongated flask having openings at both ends, means for mounting the flask with its longitudinal dimension generally vertical, an elongated former initially dis posed with its longitudinal dimension generally parallel to the longitudinal dimension of the flask, adjacent the lower portion of the flask and in position to move upwardly through the flask when the flask is mounted in the mounting mean-s and means for moving the former upwardly through the flask to form a cavity extending longitudinally of the flask in finely divided mold forming material in the flask and compact the mold forming material to form a mold for casting. Preferably the former has an operative portiontapered in the upward direction from relatively great to relatively small transverse cross section. The former may have a passageway therein receiving and removing from the flask a predetermined quantity'of the mold forming material while the former moves through the flask whereby to insure compacting the mold forming material to optimum hardness as a cavity of predetermined transverse dimension is formed. The passageway in the former preferably has its mouth at the upper end of the former whereby most effectively to receive and remove mold forming material.

I provide guide means for the formerat the bottom and top of the flask to insure movement of the former through the flask in a predetermined path. 'The means for moving the former upwardly through the flask may be disposed generally below the flask when the flask is mounted in the mounting means, or the former may have a portion of smaller cross section extending upwardly and connected with means which pull the former upwardly through the flask.

I also preferably provide auxiliary means which cooperate with the former to compact the mold forming material at at least one end of the flask. Such means may comprise an auxiliary compacting head which surrounds the former at an end of the flask and is movable.

inwardly of the flask about the former to cooperate with the former to compact the mold forming materialat that end of the flask. Such auxiliary compacting heads may be provided at both ends of the flask. The auxiliary compacting head or heads cooperates or cooperate with the former in compacting the mold forming material at one or both ends of the flask to a shape diflerent from the shape of the mold forming material at the mid portion of the flask for casting an end portion or portions of an elongated article. Preferably such means are provided at both ends of the flask so that a mold may be formed for the centrifugal casting of pipe having a hub at one end and a spigot at the other end or hubs atboth -More specifically, I preferably provide two heads, one at each end of the flask, whichsurrountl the former and engage the mold forming material in the flask and coopera ate with the former in compacting the mold forming material at the ends of the flask to shapes different from the shape of the mold forming material at the mid portion of the flask for casting the end portions of an elongated article, at least one and preferably both of the heads being movable inwardly of the flask about the former to apply additional compacting pressure to the mold forming material.

I desirably form the lower portion of the flask at about the zone which is traversed by the leading end of the former as the former initiates its upward movement so that such portion of the flask is tapered in the upward directionfrom relatively great to relatively small transverse cross section to assist in compacting the mold form ing material as the former moves upwardly therethrough. When an auxiliary compacting head is provided at at least one end of the flask, which head surrounds the former at that end of the flask and is advance-able inwardly of the flask about the former to cooperate with the formore to compact the mold forming material at that end of the flask, a portion of the flask in advance of the zone traversed by the auxiliary compacting head is preferably tapered in the direction or" advance of such head from relatively great to relatively small transverse cross section to assist in compacting the mold forming material as the auxiliary compacting head advances.

I further provide apparatus for forming a foundry mold comprising an elongated flask having openings at both ends, a base upon which the flask is mounted with its longitudinal dimension generally vertical, a superstructure disposed generally above the base, an elongated former initially disposed with its longitudinal dimension generally parallel to the'longitudinal dimension of the flask, adjacent the lower portion of the flask and in position to move upwardly through the base and flask when the flask is mounted on the base, positioning means including means on the base and superstructure for predeterminedly positioning the flask relative to the former and means for moving the former upwardly through the base and flask to form a cavity extending longitudinally of the flask in finely divided mold forming material in the flask and compacting the mold forming material to form a mold for casting. The superstructure preferably carries means cooperating with the upper end of the flask and comprising guide means for the former. Preferably the base has positioning means for predeterminedly positioning the fiask relative to the former and the superstructure carries means lowerable when the flask is in place upon the base to engage and position the upper end of the flask. The base may have guide means-for the former including a removable bushing sleeve which may be replacedby a bushing sleeve of different internal diameter to fit a former of different external diameter.

The. means carried by the superstructure adapted to co operate with the upper portion of the flask preferably has an opening therethrough through which finely divided mold forming material may be introduced into the flask. Desirably such opening is' of such transverse dimension as to guidingly receive the upper portion of the former.

Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof proceeds.

In the accompanying drawings I have shown certain present preferred embodiments of the invention in which all of the figures are diagrammatic central vertical crosssectional views through apparatus for forming foundry molds, FIGURE 1 showing apparatus for forming a mold for the centrifugal casting of single hub pipe, FIGURE 2 showing apparatus for forming a mold for the centrifugal casting of double hub pipe, FIGURE 3 showing apparatus for forming a mold for the centrifugal casting of single hub pipe with provision for removing through the former some of the finely divided mold forming material during formation of the mold, FIGURE 4 showing apparatus for forming a mold for the centrifugal casting of single hub pipe in which the former is drawn upwardly through the flask from above and FIGURE 5 showing apparatus for forming amold for the centrifugal casting of single hub pipe in which a flask tapered adjacent its ends is utilized.

Referring first to FIGURE 1, there is shown a flask designated generally by reference numeral 2 which is open both top and bottom, the flask shown being a plain hollow cylinder with spaced apart flanged steel tires 3 applied exteriorly thereto, the tires being employed in the handling and spinning of the flask is subsequent operations which are not here involved.

The foundry floor is designated by reference numeral 4, having a pit 5 therein, the pit having a main portion 5a and a central downward extenions 5b of reduced transverse dimension. Fastened to the floor 4 and spanning the pit 5 is a base designated generally by reference numeral 6 having upright supporting means 7 carrying at the top thereof a ring 8 having a annular upward pro- 'ection 9 serving as positioning and centering means for the flask 2 which sets upon the ring concentrically therewith as shown in FIGURE 1.

Mounted within the base 6 is a vertical cylinder 10 within which operates a piston 11. The cylinder 10 has at its upper and lower extremities inwardly projecting rings 12 constituting in essence integral portions of the cylinder and cooperating with reduced portions of the piston 11 as shown in FIGURE 1, the piston being sealed to the cylinder for vertical movement relative thereto by rings 13. When in its lowermost position as shown in FIG- URE 1 the piston 11 seats on the lower ring 12 of the cylinder It) at 14. Fluid under pressure may be admitted to the space 15 below the body 11 of the piston 11 to raise the piston 11 in the cylinder 10. Fastened to the lower extremity of the piston 11 by screws 16 is a ring 17 carrying set screws 18 equipped with lock nuts 19 which may be adjusted as desired and which limit upward movement of the piston 11 in the cylinder 10 by engagement with the bottom surface of the lower ring 12 of the cylinder.

The piston 11 has therethrough a vertical bore 20 within which is disposed a cylindrical bushing sleeve 21 which may be of bronze or other suitable material to serve as a guide bearing for the former now to be described. Disposed within the busing sleeve 21 for vertical guided movement relative to the piston 11 is a former 22 made of steel or other suitable material which is of solid cylindrical form but having a conical hose 23 at its upper extremity as shown in FIGURE 1. At its bottom the former 22 has a downwardly extending externally threaded projection 24 which threads into the upper end of a piston 25 operating in a guide 26 carried by a plate 27 mounted in the pit 5, the guide 26 extending downwardly from the portion 5a of the pit into the portion 5b thereof. The guide 26 is through the plate 27 sealed to a casing 28 so that the guide 26 and the casing 28 together form a cylinder in which the piston 25 operates. Fluid under pressure may be admitted to the space 29 within the cylinder beneath the piston 25 to raise the piston in the cylinder. Such raising of the piston causes upward movement of the former 22 within the bushing sleeve 21.

There is provided a superstructure 30 comprising a cylinder 31 in which operates a piston 32 having therethrough an opening 33 and carrying at its lower portion a generally inverted cup-shaped centering member having a downwardly projecting annular flange 61 internally tapered 'as shown at 62. The internal diameter of the flange 61 above the taper 62 is such as to snugly and guidingly receive the upper end of the flask 2, the taper 62 facilitating movement of the centering member 60 down over the upper end of the flask so as to center and position the flask. A circumferential series of set screws 34 are threaded through the centering member 60 and are adapted to be maintained in adjusted position bylock nuts 63. Their lower ends are adapted to ena3 gage and seat atop the upper end surface of the flask as shown in FIGURE 1. The centering member 60 also carries a plate 35 adapted to enter the top of the flask 2 and a downward extension 35 below the plate 35 having a downwardly projecting annulus 37 constituting a pattern for shaping the mold for the casting of the spigot end of a pipe.

Mounted atop the piston 11 is a ring 38 carrying a hub pattern 39 as shown in FIGURE 1.

At the beginning of a cycle the piston 25 is in its lowermost position seated upon the bottom of the casing 28 as shown in FIGURE 1, the piston 11 is also in its lowermost position as shown in FIGURE 1 and the piston 32 is in its uppermost position with the enlarged portion 40 thereof in engagement with the upper head 41 of the cylinder 31. The flask 2 is positioned atop the base 6 and centered by the annular upward projection 9 as shown. Fluid under pressure is then admitted above the enlarged portion d of the piston 32 which lowers the piston until the set screws 34 engage the top of the flask 2, the plate 35 and the extension 36 therebelow entering the flask and the flange 61 embracing the upper end of the flask as shown. This positions the flask for formation of the mold. The setting of the set screws 34 determines the extent to which the plate 35, extension 36 and annulus 37 enter the flask which of course determines the extent to which the finely divided mold forming material in the flask is compacted or in other words the hardness of the mold.

A measured quantity of finely divided mold forming material such as specially prepared foundry sand is then introduced downwardly through the opening 33 inthe piston 32 to substantially fill the flask 2, the former at that time being in the position shown in FIGURE 1.

ternatively, the measured quantity of finely divided mold forming material may be introduced into the flask 2 when the piston 32 is in its uppermost position so that direct access may be had to the flask to introduce the mold forming material directly into the upper end of the flask instead of through the opening 33. Indeed, the superstructure 39 may, if found necessary or desired, be mounted for movement out of the way'of the flask to facilitate setting the empty flask in place on the base and removing the flask with the formed and compacted mold of finely divided mold forming material therein and also to facilitate introduction of the mold forming material into the initially empty flask.

Next fluid is admitted into the cylinder 26-28 below the piston 25 and the former 22 is moved upwardly through the finely divided mold forming material 42 in the flask 2, the former forming a generally vertically elongated cavity in the mold forming material and compacting the mold forming material between the former and the inner wall of the flask. The diameter of the opening 33 in the piston 32 is such that when the former enters that opening it is guided thereby. When the former has moved up until the cylindrical portion thereof substantially reaches the annulus 37 upward movement of the former is stopped. When the former reaches that position the conical nose 23 thereof is disposed entirely Within the opening 33 in the cylinder 32 and the cylindrical portion of the former below the conical nose completely closes the opening 33 so that the mold forming material in addition to having been laterally compressed by the former during formation of the cavity therein is completely enclosed within the flask 2.

Fluid under pressure is admitted to the space below the body 11' of the piston 11 to raise the piston in the cylinder It). This causes upward movement into the flask of the ring 38 carrying the hub pattern 39 and additionally compresses the mold forming material 42. This completes formation of the mold of finely divided mold forming material 42 in the flask 2, the mold having at its upper end a depression formed by the annulus 37 for formation of a spigot on one end of the pipe to be centrifu gally cast in the mold and the hub pattern 39 forming an enlarged cavity at the oppoiste end of the mold in which the pipe hub is cast. The ring 38 forms in the lower end of the mold a seat for the core used information of the hub when the pipe is cast.

The former 22 may be replaced with a former of different transverse dimension. Iffor example a former of smaller transverse dimension is to be used the former 22 is unscrewed from the piston and the new smaller former is screwed in place and the bushing sleeve 21 is replaced by a bushing sleeve having the same outside diameter but a thicker wall so as to properly guide the smaller size former. Also the piston 32 may be replaced by a similar piston having an opening therethrough of smaller diameter than the opening 33 or a sleeve may be inserted into the opening 33 of the piston 32 whose internal diameter is such as to snugly receive the cylinrical portion of the smaller former.

After the mold has been formed the

pistons

25, 11 and 32 are moved back to the positions which they occupied at the commencement of the cycle, freeing the flask and mold for removal to a casting station. After removal of the flask with the finished mold therein an empty flask is set in place and the cycle is repeated.

Referring now to FIGURE 2, the apparatus shown therein while of somewhat different form than the apparatus of FIGURE 1 is generally identical thereto in function except that the apparatus of FIGURE 2 as shown forms a mold for the casting of double hub pipe while the apparatus of FIGURE 1 forms a mold for the casting of single hub pipe. The apparatus of FIGURE 2 may be easily converted to form single hub pipe by replacing the hereinbelow referred to hub pattern 37a by an annulus like the annulus 37 of FIGURE 1. Double hub pipe has hubs at both ends whereas single hub pipe has a hub at one end and a spigot at the opposite end. 1

In FIGURE 2 the piston 32a which is analogous to the 2 nated 25a and the piston or carrier carrying the lower.

hub pattern 39a is designated 11a. In the specific structure shown in FIGURE 2 the former 22a is shown as being integral with the piston 25:: although the former:

may be made removale as in FIGURE 1 if desired. Also in FIGURE 2 adjustable set screws 43 are provided on the former for engaging a downwardly projecting portion 44 of the carrier 11a to move the carrier upwardly when the former 22a has reached the position with its cylindrical portion within the upper hub pattern 37a. The former will move the carrier 11a upwardly, compressing springs 45. Upward movement of both the former 22a and the carrier 11a is stopped when the piston 25a reaches the top of cylinder 28a. When the piston 25a moves downwardly the springs 45 draw the hub pattern 39a out of the mold. Thus the form of apparatus of FIGURE 2 utilizes one less cylinder than the form of FIGURE 1 although accomplishing the same result. Also, of course,

the mold formed by the apparatus of FIGURE 2 produces a double hub pipe whereas the mold formed by the apparatus of FIGURE 1 produces a single hub pipe.

There is one further difference between the possible operation of the apparatus of FIGURE 1 and that of FIGURE 2. With the apparatus of FIGURE lthe upward movement of the piston 11 can be started at any time during the movement of the former 22 which may be found desirable. In certain instances it may be desirable to initiate the upward movement of the piston 11 when the former 22 has traversed, say, between one-half and three-quarters of its full stroke upwardly. This can be done with the apparatus of FIGURE 1 since in'that ap- 3 piston or carrier 11a is operated by the piston a by means of the former 22a and the set screws 43 as above described.

FIGURE 3 discloses apparatus which is the functional equivalent of the apparatus of FIGURE 1 except that in FIGURE 3 the former 22b is hollow. The hollow former 22b has a conical nose 231), but the-nose is cut oil at 45 so'that the leading end of the former as it moves upwardly through the mold forming material in the flask 2b presents an open mouth into which some of the mold forming material in the flask enters. The mold forming material which enters the mouth at the upper end 45 of the former 22b passes down through the former and out through openings 47 at the bottom of the former into the pit 5b.

The conical nose of the former may be made removable and replaceable so that a conical nose may be selected which has a mold forming material receiving opening or mouth of desired size whereby the quantity of mold forming material passing downwardly through the former may be predetermined. Thus the quantity of mold forming material remaining the flask may be predetermined with the result that rather precisely controlled compacting of the mold forming material may be attained. Since the motions of the pistons are fixed for any particular adjustment the controlled quantity of mold forming material in the flask as determined by the selection of the conical nose of the former will be compacted to the extent desired. Ths feature increases the flexibility of the apparatus; for example, use of a conical nose with a mouth of s and 3 a deep pit of substantial size has to be provided for receiving the cylinder in which operates the piston which carries the former. In certain instances'the provision of such a pit may be undesirable. The apparatus shown in FIGURE 4 makes possible the use of a considerably shallower pit of smaller transverse dimension which, moreover, need not be internally finished The former 22a of FIGURE 4- has a conical nose 230 which, however, does not extend to a point but terminates in a flat face 48. Threaded thereinto at 49 is a stem 59 which extends upwardly through the opening 330 in the piston 32c and through a guide 51 where it is connected with a cable 52 which. passes over a sheave 53 to a drum 54 upon which the cable is adapted to be wound up and from which it may be payed out.

Connected with the bottom of the former 220 at 55v is a guide stem 56 which operates in a bushing sleeve 21c in the piston 11c. Thus the former 220 is guided both by the bushing sleeve 21c and through the stem 56 by the guide 51, and operative movement of the former is effected through the cable 52 rather than by a piston in a cylinder below the former as in FIGURES l, 2 and 3, such piston and cylinder being rendered unnecessary. The pit 50 need be only deep enough to receive the guide stem 56 and may also be of considerably smaller transverse dimension than a pit required to house a cylinder as in FIGURES 1, 2 and 3. Upward movement of the former 22c is brought about by winding up the cable 52 on the drum 54, and when the drum 54 is turned in the counterclockwise direction viewing FIGURE 4 the former 22c moves-downwardly by gravity to its lowermost position as shown in that figure. Downward movement of the former 220 of FIGURE 4 is limited by the seating of the former in the upper portion of the piston He at 57.

The stem 50 may be replaced by a stem of ditferent transverse dimension if desired. The stem displaces a predetermined volume in the flask 2c when the elements of the apparatus are positioned as shown in FIGURE 4-, thus limiting the quantity of mold forming material which may be introduced into the flask. By substituting a stem of different transverse dimension the. quantity of .mold

forming material which the flask will receive is altered with the result that the extent to which the fold is compasted in operation of the apparatus of FIGURE 4- may be controlled. In other words, the removable and replaceable stem 59 of FIGURE 4 provides a control factor analogous to that of the removable and replaceable nose 23b of the former of FIGURE 3.

As is apparent from FIGURE 4, upward movement of the piston lie with the former 22c seated thereon at 57 causes upward movement together of the former 22c and the ring and hub pattern atop the piston and with which the former interfits and, of course, the piston itself. Such movement at the beginning of a mold forming cycle causes optimum compression of the mold forming material at the bottom of the flask 2c as the former starts upward so that after upward movement of the piston has stopped and the former advances upwardly by itself through winding up of the cable 52 on the drum 54 the then compacted mold forming material acts to guide the former by the cylindrical portion thereof which was initially disposed within the ring and hub pattern. This renders unnecessary prolonged guiding of the former by the guide stem 56 and the guide stem may be made very short or eliminated altogether since the former is guided by the ring and hub pattern until the trailing bottom end of the cylindrical portion of the former emerges from the hub pattern, by which time the mold forming material ahove the hub pattern is sufficiently compacted to guide the former.

FIGURE 5 shows apparatus similar to that of FIG- URE 3 except that the flask 2d of FIGURE 5 has tapered

portions

58 and 59 adjacent its upper and lower ends respectively and provision is made for compacting the mold forming material at the upper portion of the flask as well as at the lower portion of the flask in addition to the compacting aflorded by the former 22d. The tapered portion 59 of the flask is shown as being disposed at substantially the zone at which the conical nose 23d of the former 22a is positioned when the former is in its lowermost position so that when the former starts to move upwardly with the flask filled with finely divided mold forming material any tendency of the conical nose 23d of the former to push mold forming material upwardly will result in compacting of the mold forming material to a greater extent than if the tapered portion 59 of the flask were not provided; this is because any upward movement of the mold forming material at the tapered portion 59 of the flask causes the mold forming material to occupy a smaller space than it occupied before the upward move, the result being compacting of the mold forming material to an extent to which it would not be compacted in a plain cylindrical flask.

The tapered portion 59 of the flask 2d also cooperates with the piston 11d carrying the ring 38d and the hub pattern 39d to quite materially compact the mold forming material in the flask when the piston 11d moves upwardly to an extent greater than that to which the mold forming material would be compacted by upward movement of the piston in a plain cylindrical flask as the mold forming material is bodily forced upwardly at the zone of the tapered portion. 59 of the flask and hence squeezed into a smaller space than it previously occupied.

The apparatus of FIGURE 5 also differs from the apparatus of FIGURES 14 in that the downwardly projecting annular flange such as the flange 61 of FIGURE 1 and the set screws such as the set screws 34 of FIGURE 1 are eliminated and the plate 35d carrying the downward extension 36d with the annulus 37d is free to move without restriction downwardly into the upper end of the flask. The plate 35d serves the dual purpose, as the piston 32d moves downwardly, of centering or positioning the upper portion of the flask and compacting the mold forming material 42d at the upper portion of the flask. The plate 35d would compact the mold forming material at the upper portion of the flask whether or not the flask were provided with the tapered portion 58, but the provision of the tapered portion 58 brings about compacting of the mold forming material to a materially greater extent than would be the case in a plain cylindrical flask, the action in the zone of the tapered portion 58 being the same as that in the Zone of the tapered portion 59 as just explained.

In normal operation the piston 32d will initially be moved downwardly only far enough to position the plate 35d within the upper end of the flask to center or guide the flask. Thereupon the mold forming material will be delivered into the flask through the opening 33d in the piston 32d if it has not already been introduced directly into the flask as above described instead of through the opening 33d. Next the former 22d will be moved upwardly through the mold forming material until its cylindrical portion enters the opening 33d which causes the mold forming material to be completely enclosed within the flask. Preferably at that time the piston 11d will be moved upwardly and the piston 32d will be moved downwardly to finally compact the mold forming material in the-flask about the former.

Features of the methods herein disclosed are claimed in my copending application, Serial No. 118,002, filed June 19, 1961, now abandoned.

While I have shown and described certain present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claim.

I claim:

Apparatus for forming a foundry mold comprising an elongated flask having openings at both ends, means for mounting the flask with its longitudinal dimension generally vertical, an elongated former initially disposed with its longitudinal dimension generally parallel to the longi- I 1 0 tudinal dimension of the flask, adjacent the lower portion of the flask and in position to move upwardly through the flask when the flask is mounted in the mounting means and means for moving the former upwardly through the flask to form a cavity extending longitudinally of the flask in finely divided mold forming material in the flask and compact the mold forming material to form a mold for casting, the former having a passageway therein receiving and removing from the flask a predetermined quantity of the mold forming material while the former moves through the flask whereby to insure compacting the mold forming material to optimum hardness as a cavity of predetermined transverse dimension is formed.

References Cited by the Examiner UNITED STATES PATENTS 181,368 8/76 Smith 22-17 349,461 9/ 86' Schickle 22-17 806,329 12/ 05 Dimmick 22-17 878,471 2/08 Swift 22-17 1,079,959 12/13 Swif-t 22-17 1,134,404 4/15 Ogden 22-17 1,768,451 6/30 Hume 25-36 1,977,257 10/34 Williams 25-36 2,143,449 1/ 39 ORourke 25-36 2,757,424 8/56 Daniel 22-10 2,791,013 5/57 Demrnler 22-10 2,879,563 3/59 Ewing 22-17 3,060,539 10/62 Norton 25- 34 FOREIGN PATENTS 423,349 2/11 France. 544,822 10/3 0 Germany.

- MICHAEL v. BRINDISI, Primary Examiner.

ROBERT F. WHITE, MARCUS U. LYONS, Examiners.