US2641033A - Molding apparatus - Google Patents

Description

Filed Feb. '7L/1,8950 /0 2 Sheets-Sheet 2 /zx I V .ff l 1 I /z /0 '/,z /0

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Afm/'new Patented June 9, 1953 UNITED STATES ATENT OFFICE MOLDING APPARATUS of `Ohio Application February '7, 1950 Serial No; 142,877

1 Claim. 1

This invention relates to molding apparatus and more particularly to an improved means for establishing `and maintaining alignment between a plurality of elements of a separable ,foundry flask during assembly, use, and disassembly.

Such aligning means are particularly applicable to a separable foundry flask made up of separable portions known as cope and drag elements which are .adapted to be used cooperatively in surmounting relation'. In some Cases the drag element comprises a hollow box-like member while in others it comprises a pattern plate, but in either case, it is desirable to establish and maintain a constant alignment 'between the individual elements during assembly into .a foundry flask, during the molding operation, and during the disassembly or separation of the ask.

Tn the use of separable foundry flasks as commonly employed, various attempts have been made to establish and maintain operating alignment. Perhaps the commonest vform is the use of a solid pin and complementary bushing at each end of the assembled foundry flask, the pin at one end being a solid round pin cooperating with its complementary bushing in a snug manner and the pin at the other end being non-circular in cross section and cooperating with a complementary non-circular bushing to form Ya snug Ilit in a sidewise direction and a loose fit in a direction extending longitudinally of the flask. This arrangement prevents sidewise movement and allows for a certain amount of longitudinal shift of one separable element of the foundry ask with respect to the `other to aid in their separation.

In normal use however, the foundry flask will tend to expand due to the heat of the metal which is poured into the mold, thus tending to bind the solid pins in their sockets. This binding may be further enhanced by a difference in volumes of the metal in the respective separable elements or sections. `As a result it is common practice to increase the clearance or tolerance between the pins and the complementary bushings. Suc-h increased tolerances however, allow small grains of sand to lodge between the pins and bushings, thereby causing further binding and accelerating the wear. Furthermore, if a cope element is placed or rammed on the side of the tolerances and then removed and closed on the other side of the tolerance and then poured, it will show the .double amount of shift in the castings and also result in an increased tendency to rock lbetween the cope, drag, and pattern which causes breaking and crushing of the sand.

This binding action, excessive shift, vand tendency ofthe elements to rock results in scrap castings and excessive wear on the aligning means and is Ione 4of the principal problems in the highly vcompetitive foundry industry. The problem is of particular significance in the case of so-called finished castings which are not machined after the molding operation and as a result the amount of yundesirable shift becomes a controlling factor in the quality of the end product.

Various attempts have been made to offset these disadvantages by employing other types of alignment means such as rsingle round pins, double round pins, V-pins, and W-shaped pins on the ends of the drag with half round V and Jv-shaped pins on the ends of the cope element.

Although such arrangements tend to minimize some of Ythe binding and rocking motion when lifting the cope element off the flask or pattern plate, there are certain inherent disadvantages in that the vpins are put in rigid and the guides on the cope element are -adjusted to the pin,

` thereby rendering it difficult to arrive at the correct tension on the pins and correct alignment between the pins, guides, pattern plate, and the cope and drag elements. The jolt and squeeze of the molding machine is usually sufficient to disrupt the adjustment and if the guide members are tightened sufficiently to arrive at and maintain the correct fit and alignment, the wear is so great that a number of adjustments may be required 'in any one day. Such adjustment must be done 'by an experienced mechanic to properly align the flask. Otherwise, the adjusta'bility of the guide members is an invitation to the molder to make his own adjustment and thereby throw everything out of line causing shifted and scrapped castings.

The primary object of the present invention therefore is to provide an improved arrangement for establishing and maintaining a satisfactory alignment ,between the elements of a separable foundry flask during assembly, molding, and disassembly.

It is a further object of this .invention to provide complementary alignment means for a separable foundry flask which will maintain a snug t at all times and which -will automatically take up the wear between the respective complementary alignment means, and which does not require adjustment `of the aligning means.

These and other `objects ,and advantages `of the invention will `be further understood from the following description, when considered in connection with the accompanying drawings, and in scope as pointed out in the appended claim.

In accordance with the invention we provide a slotted pin which is preferably mounted in a solid center at each end of a separable element of a foundry flask and which is adapted to cooperate with a guide bushing mounted at each end of a coacting separable element. The spring tension of the pin arms maintains a snug fit with the inner wall of the cooperating bushing so as to hold the flask elements together and yet facilitates removal in an expeditious manner.

In the drawings, Fig. 1 is a top view of a foundry flask embodying the improved alignment means; Fig. 2 is a vertical section on the line 2-2 through the foundry flask showing in detail the cooperating arrangement between the slotted pins and complementary bushings; Fig. 3 is a vertical section showing the improved alignment means as applied to a pattern plate; Fig. 4 is a detail of the slotted pin showing part of the guide bushing and retaining nut in cross section and also showing in dotted lines the taper of the slotted pin with the bushing riding at the base of the taper; Fig. 5 is a top View of the slotted pin of Fig. 4 showing in dotted lines the increased area at the top due to the taper; Fig. 6 is an alternative embodiment of the invention showing a diametric transverse slot at the base of the longitudinal slot in the pin; Fig. '7 is a top view of the pin of Fig. 6; Fig. 8 is another form of the invention showing a vertical sinuous spring member disposed within the longitudinal slot; Fig. 9 is a top view of the pin of Fig. 8; Fig. 10 is still another embodiment of the pin illustrated in Fig. 8 but showing the use of a hairpin spring seated in the top of the slot of the pin; and Fig. l1 is a top view of the pin of Fig. 10.

Referring now to Fig. 1 and Fig. 2, element I is a cope and element 2 a drag, both being separable elements or snap flasks of the type to which the invention may be applied. The cope and drag elements may be each vertically parted at diagonally opposed corners, and the sides may be aligned and secured at the parting lines by bolts or filler members, or, as shown at 3, by means of the bolt, cam, and handle arrangement disclosed and described in U. S. Patent 2,289,269 issued on July '7, 1942.

The cope element I is preferably provided with a laterally extending external lug 4 at each end and the drag element 2 may be provided with a pair of laterally extending external lugs at each end designated as 5 and 6 respectively. Each of these lugs may be provided with apertures "I, 8 and 9 respectively so arranged that when the cope element surmounts the drag element as shown in Fig. 2, the apertures on each end of each of the extending lugs are in substantial axial alignment with those of the adjacent lugs respectively and are adapted to receive the pin Ill and bushing I I.

The pin I0 is a solid pin having a diameter slightly less than the inner diameter of the bushing II and is slotted in a direction parallel to its longitudinal axis as shown at I2. This slot extends substantially the greater part of the length of the pin and is cut while the pin is held in a fixture. The fixture presents the arms from springing apart during the cutting operation, but upon being released from the fixture the free ends of the arms automatically spring away from each other as shown by the dotted lines in- Figs. 4 to 11 respectively. The extent of such deviation is sufficient to require a compressive action of the arms toward each other to admit them into the coacting bushing, whereupon the inherent tension therein maintains a firm frictional engagement with the bushing, and compensates automatically for any Wear therebetween.

In the assembly of Figs. 1 and 2, each slotted pin I0 is first inserted through the aperture 8 in the lug 5 and is abutted against the lower lug 6. A threaded extension I3, of lesser diameter than the pin, extends through the aperture 9 in the lowermost lug 6 and may be secured in this position by a lock nut I4 which is threaded thereto.

The cope element I carries the bushings or guide members II in the apertures 'I of the lugs 4. Each bushing II may have a shoulder which abuts one side of the coacting lug 4 to restrict axial movement of the bushing in one direction, while a cooperating lock washer I6 and nut II act on the other side of the lug to restrict axial movement of the bushing in the opposite direction. The cope element I with its bushings II may then be mounted on the drag element 2 in surmounting relation by sliding the bushings II over the respective slotted pins I0. To facilitate such assembly operation the head of each pin is tapered.

The pair of arms resulting from the slot I2 in the pin I0 provides inherent spring-like characteristics due to the increased diameter or area at the top of the pin, and when cooperating with the complementary bushing II in the assembled condition, results in friction between the inner wall of the bushing and pin. This friction is sufficient to hold the cope and drag elements in optimum alignment and to take up wear automatically between the pins and the complementary bushings.

Referring now to Fig. 3, wherein like numerals designate like parts, the foundry flask element I8 is shown mounted upon a pattern plate I9 by means of the slotted pin I0 and complementary bushing II aligning means of the present invention. Other forms, modifications, and applications of this invention will be evident to those skilled in the art.

Referring now to Fig. 4, which is a detailed showing of the alignment means of this invention and also of a cut-away section of the bushing II and the pin retaining nut I4, we have found that the tension on the spring-like arms resulting from the diametric slot I2 in the pin I0 can be determined by the length of the slot. Thus, depending upon the extent of friction desired between the pin and complementary bushing, the slot may be made deeper or shorter accordingly. The inherent spring-like characteristic and the tendency of the arms to expand is shown in the dotted lines in Figs. 4 and 5, wherein it will be seen that when the complementary bushing I I is positioned upon the pin I0, its ultimate position will be near the base of a taper resulting from this spring-like tendency. We have found that in the assembly of Fig. 2 best results are obtained when the base of the slot I2 terminates beneath or approximately in the region of the upper lug 5.

Referring now to Figs. 6 and '7, we show a modied form of our slotted pin having an enlarged slot 2U disposed diametrically transversely to the longitudinal axis of the pin I0 at the base of the slot I2. The presence of the slot 20 provides another condition of control over the tension of the spring arms of the pin by varying the diameter or cross section oi the opening in the transverse slot.

In Figs. 8 and 9, we show another form of our alignment means which embodies the use of a sinuous spring 2i disposed within and extending the length of the slot Iii. The use of the sinuous spring 2l provides a still further condition on the control of the tension ci the spring arms oi the pin lll and may be used whenever a greater degree of friction between the pin il? and bushing i i is desired than can be obtained with the slotted pin arrangement shown in 4. and 5.

A further modied form ci the arrangement shown in Fig. 4 is illustrated in l0 and 1l wherein a concentric hole 22 extends axially from the free end of the pin and is iitted with a U- shaped or hair-pin type spring member 2t. The modified form in Figs. and 11 provides further conditions of tension control of the aforementioned spring arms by reason of the spring 23 and by varying the diameter and depth of the hole 22.

In the preferred form. we iind that satisfactory results are derived from the alignment means of this invention when the slot of one oit' the pins extends transversely to the longitudinal axis of the flask while the slot of the other pin, installed at the other end of the flask, extends parallel with the longitudinal axis of the ask as shown in 1. That arrangement however is not necessary to a successful operation of the assembly, but is merely suggested as a satisfactory plan. Thus in the preferred arrangement, we have found that the pin which is so placed that its slot extends transversely to the longitudinal axis of the flask compensates for and eliminates side play and rocking motion of the ask, while the pin having its slot extending parallel to such axis compensates for and eliminates binding and shifting in the longitudinal direction. The result is such that upon assembly of the elements there is optimum alignment which is maintained under tension throughout the molding operation and during subsequent separation of the foundry flask.

Although We have shown the application of the invention to a separable foundry mold flask, it may also be applied to any composite assembly of a similar nature wherein an initially established alignment is desired to be maintained through subsequent operations. Among the advantages of the improved alignment means is the substantial elimination of scrap castings due to the elimination of shift between the separable elements of a separable foundry iiask, the automatic taking up of Wear between the complementary aligning elements, and lthe automatic correction of imperfections in the manufacture of the pins and bushings of such an arrangement.

While we have shown and described what we consider the preferred embodiment of the invention along with similar modified forms, it will be obvious to those skilled in the art that other changes and modifications, particularly with respect to the structure and manner of controlling the tension inherent in the slotted pin and of its applications, may be made without departing from the scope of the invention as defined by the appended claim.

We claim;

In a foundry flask having a mating pair of separable hollow members adapted to be assembled in surmounting relation, means for establishing and maintaining alignment between said hollow members including a pin having a progressively increasing cross-sectional area from one end towards the other and having means for permitting the large area end to be resiliently squeezed together for insertion into a guide bushing, said last-mentioned means consisting of the axial portion of said pin having an open split extending along its longitudinal axis from the large area end throughout the maj or portion of its length and terminating short of the other end to form an integral base having a pair of outwardly diverging ringer portions freely extending therefrom, each of said hollow members having external apertured lugs extending laterally therefrom, means for securing the integral base of said pin in the lug on one of said members whereby the split end of said pin extends towards a lug on the second of said members, a tubular guide bushing having an external thread with a head at one end and adapted to be carried in the lug aperture of said second member with the head engaging one side of the lug to restrict relative movement in one direction therein, said tubular guide bushing adapted to receive the extended split end of said pin therethrough in compressed snug-ntting engagement to retain said hollow members in aligned surmounting relation, and a nut adapted to engage the external bushing thread on the other side of the corresponding lug to restrict relative movement in the other direction therein.

RUSSELL J. HINES. ARTHUR C. HINTZ.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,376,602 Cannon May 3, 1921 1,438,633 Byerlein Dec. 12, 1922 1,556,368 Sperry Oct. 6, 1925 FOREIGN PATENTS Number Country Date 5,799 Great Britain Mar. 7, 1912 663,837 France Apr. 15', 1929 528,173 Germany June 26, 1931

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