US2620529A - Pattern and pattern making - Google Patents

Description

Dec. 9, 1952 K. T. RINDERLE PATTERN AND PATTERN MAKING 2 SHEETS-SHEET 1 Filed July 1, 1949 R. mm M me n e, VM 0 mm [wr r E ve r m n 4 Q. f6 5 7.,.

J l -A f6 Dec. 9, 1952 K. T. RINDERLE 2,620,529

y l, 1949 2 SHEETS-SHEET 2 IU Il INVENTOR.

KAR/ 7'. E/NDEELE.

Patented Dec. 9, 1952 UNITED STATES PATENT OFFICE Brown Industries Incorporated,

Sandusky,

Ohio, a corporation of Ohio Application July 1, 1949, Serial No. 102,610

9 Claims.

This invention relates to patterns and pattern making and more particularly to a novel method of forming fillets in the angles of such patterns and the provision of a smooth and wear-resistant surface thereon.

Dead sharp inside corners are not permissible on any portion of a pattern, whether constructed of metal, wood, or other material, where such pattern is to be employed in the shaping of a sand mold. The usual molding sand is, of course, granular in form and obviously cannot be rammed completely into such corners. There will always be interstices between the grains of sands which leave weak and unsupported corners in the finished mold easily damaged in handling and subject to erosion and penetration by the molten iron or other metal during pouring. By rounding such inside corners of the pattern, however, it becomes possible to fill the same completely With properly packed sand so that the resultant edge or corner of the finished mold is reinforced and self-supporting. Additionally, there are various metallurgical reasons for avoiding a sharp sand :fe-entrant angle in a mold. These factors are Well understood in the art, and it is consequently a universal practice to provide fillets in such pattern angles and also in the angle Where the pat- 'tern joins the pattern plate. Such fillets are ordinarily formed to provide a slightly concave contour between the planes of the angle, the radius of the fillet required varying with the size of the grains of the molding sand or other medium, a relatively small radius being satisfactory when fine sand is to be employed and a larger radius being necessary when a coarser grade of sand is used. Such fillets are regularly provided on wood or plaster master patterns and, where metal patterns are cast integrally on a plate, a llet is provided at the joint by the pattern founder. On the other hand, when metal patterns are mounted on a separate metal plate, the mating surfaces require to be machined, resulting in a dead sharp corner at the joint. The foundrymen therefore add a fillet at such joint using such materials as beeswax mixed with aluminum powder, sealing wax, lacquer, various liquid sol- When wooden patterns are made, the necessary fillets have been provided in a variety of ways: by carving the same from the solid block of wood of which the pattern is formed; glueing in preformed wooden fillets; melting in wax and then forming the fillet by application of a hot metal rod; glueing in a preformed fillet consisting of an outer cloth covering and an inner Wax filler; rubbing in a shaped wax fillet; glueing in a shaped leather or plastic fillet; forming a iillet of plastic wood or crack filler; building up a llet with paint, shellac, lacquer, metal spray, glue, and liquid solder; forming the fillet of "caulking compounds; putty, or molding clay. None of the foregoing expedients has proven satisfactory in practice although each method is currently employed in one foundry or another. Such fillets rapidly deteriorate in use and before long it is found that the molder in the foundry repairs the same with such materials as clay dug from the floor or taken from a cupola mud box. Inferior castings and scrap are the ultimate result.

The reasons for failure of these various expedients include expansion and contraction of the pattern components in use and storage which tearV the applied fillets loose and crack the carved ones. Moisture may cause the edges of such applied fillets to curl back, while wax fillets tend to harden in cold weather and drop off or get soft and sticky in warm weather. causing sand to adhere thereto. Fillets of paint, lacquen'crack filler, etc.. also fail due to expansion and contraction of the pattern parts, jolting ofthe mold on the molding machine and the vibration or rapping usually employed to facilitate the draw.

It is therefore a primary object of this invention to provide a novel fillet which will have none of the lforegoing disadvantages but which can normally be expected to last for the life of the pattern.

Another object is to provide a method of forming such fillet which is equally applicable to both wooden and metal patterns.

Where a large number of identical castings are to be produced, it is the usual practice to employ metal patterns since the same naturally outlast wooden patterns and are more accurate in their dimensions and smoother of surface, On the other hand, Where the number of castings to be made is insufiicient to justifyr the higher cost of such metal patterns and it is not necessary to hold to such precise dimensions, wooden patterns are customarily employed. It has been appreciated by workers in the industry that a wooden pattern surfaced with applied metal or other equivalent smooth and wear-resisting material Would be highly desirable as providing the advantages of the more expensive metal patterns at a much reduced cost. Attempts have accordingly been made to spray various molten metal alloys on the usual wooden patterns but such attempts have achieved but indifferent results. In the r'st place, the applied thin film of metal has failed to adhere satisfactorily to the underlying pattern, particular difficulty arising at the llets. In the second place, such fillets still tend to break down in use despite the thin metal coating applied thereover. It is therefore a further object of my'invention to provide a metal surfaced wooden patternlwhich will have all of the advantages of the usual metal patterns and in Which the applied metalcoating will Vbe permanently bonded to the underlying pattern.

Still another object is to provide such metalcoated pattern having llets which will not loosen or otherwise deteriorate in use.

Other objectsv of :the invention `will appear .as the `description proceeds.

To the accomplishment .of the foregoing rand related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and vthe annexed drawing setting forth in detail certain .illustrative embodiments `of the invention, these being indicative, however, of but a fewof the various Ways in which the principle of the invention may-be employed.

In said annexed drawing:

Fig. 1 is a top plan view of a 4pattern plate formed in accordance with myV invention for mounting of an appropriate pattern thereon;

Fig. 2 is a side elevational lview of such Ipattern plate;

Fig. 3 is a top plan View of such pattern plate showing a pattern mounted thereon together with the means which I employ to form an appropriate fillet at the juncture of such pattern and pattern plate; v

Fig. 4 Vis a side elevational View of the assembly of Fig. 3;

Fig. 5 is an end elevational View of the assembly of Fig. 3

Fig. 6 is a fragmentary sectional view taken through such assembly along the line 6-.6 on Fig. 3; i

Fig. '7 is a similar fragmentarysectional view taken on the line 'I-"I on Fig. 3;

Fig. 8 is a vertical sectional view taken on the line 8-8 on Fig. 3;

Fig. 9 is a top plan view of the pattern plate and pattern mounted thereon after formation of such fillet; and

Fig. 10 is a fragmentary vertical sectional view taken along the line Ill-I on Fig. 9, also showing the metal surface coating applied to such pattern and pattern plate.

Referring noW more particularly to said drawing, I illustrate the formation of a 'fillet in the joint between the pattern and pattern plate, although it will be appreciated that fillets may similarly be applied in other pattern angles. The pattern I is placed upon the pattern plate 2 in the position it is to occupy thereon and aline is traced thereabout on such pattern plate. A groove 3 is then routed out in the upper surface of the pattern plate with` such .line constituting the approximate center line of the groove. The edges of the groove will preferably be undercut much like a keyway.

The pattern is then secured to the pattern 4 plate by means of dowels 4 inserted in holes 5 in the pattern and corresponding holes 6 in the pattern plate. An adhesive may also be applied to the mating surfaces if desired.

Referring now more particularly to Figs. 3-8 inclusive, I next place a length of ordinary leather belting 'I having a circular cross-section closely around the pattern in the vangle between the latter and the patternplate, the radius of such belting being the same as that desired in the fillet to be produced. As shown in Fig. 8, the belting closes that portion of groove 3 left exposed by pattern I. Such belting is secured in place by coveringxthesame with an oil base modeling cla-y A8 which has been worked sufficiently soft that -it may be applied with a single stroke of the thumb. Such clay need not be applied with great care since its function is merely to hold the `belting tightly in position.

At the mid-point 9 of the belting an instrument .such as a lead pencil is now inserted between the shown in Figs. 3 and 4.

A similar funnel-shaped opening Il will now .be formed at I2 where the ends of the belting are brought together. f y

I now melt an alloy of bismuth, lead, tin and cadmium lweighing approximately 4.35 pound per cubic inch, which alloy begins to melt at F. and is completely molten at 190 F. Such alloy should not be heated over 250 F. This molten alloy is now pouredinto the funnel-shaped opening or gate ,IIJ in a steady stream. After allowing a few minutes for cooling, the belt 'I may be stripped from the assembly. carrying most of the clay with it and the alloy Will be found to have rcompletely filled groove 3 and to have formed a llet corresponding to the radius of the belting. A metal rod is warmed and the end applied to the juncture of the gate and the llet to soften and remove such gate. It is undesirable to heat the metal fillet to a temperature Where it will actually melt since the surface tension of the molten metal acts to round on the otherwise sharp juncture of the llet edge with the pattern.

The same process may be employed in the case of 'a metal pattern but such pattern should nrst be heated yuntil it is Warm to the touch, on the order .of 11,50 F., for example. This may be done quite easily by submerging the pattern in hot water and then drying the same.

The above-described alloy, which is commercially available andy sold under the trade-name of Cerrosafe, expands slightly about one day after casting so that the fillet is `firmly and permanently gripped in the undercut cavity t. It will not loosen in use and it is unaffected by liquid parting, kerosene, water, vibration and rough handling. In the event of damage the fillet can usually be quickly and easily repaired in the Afoundry with the end of a warm metal rod.

As above indicated, such novel metal llet I5 has been found to be particularly advantageous when employed in conjunction with a thin metal coating I3 subsequently applied to the surface of the wooden pattern and pattern plate.Y The usual mahogany pattern after being thoroughly cleaned will have a glue or cement I4 applied thereto which should be spread quite thinly and permitted to become slightly tacky. A preferred adhesive for this purpose is a plastic glue having a high rubber latex content. Other types of adhesive such as shellac have been rfound to be generally unsatisfactory. The same metal alloy used for the fillets is now sprayed' on the pattern and pattern plate, using ar low temperature alloy spray gun which is preferably of a type wherein the compressed air is preheated to hold'the particles of atomized metal at the proper temperature. The thin metal coating I3 thus applied cools immediately and adheres strongly to the pattern and pattern plate including the metal llets l5 previously provided thereon (Fig.

Such metal surfaced wooden patterns not only last much longer in use but also give a superior surface to the molds formed thereby. The usual liquid parting fluids which are'regularly employed with metal patterns may likewise be employed with the same and the metal surface becomes smoother the more the pattern is used. If after a long period of use the metal surface should begin to wear through in spots, a new coating may be applied. The plastic adhesive which was applied prior to spraying on the metal, however, becomes quite hard when set and itself provides a hard smooth surface in any minor areas where the metal may thus eventually be worn away. Such metal surfaced wooden patterns are, of course, much less expensive than the all-metal patterns. Important factors in the production of a satisfactory metal surfaced wooden pattern include the employment of my new metal fillet, the use of a plastic adhesive rather than shellac or the like, and the use of a low temperature alloy spray rather than the high temperature metal sprays sometimes employed for other purposes. .v

It will, of course, be understood that the principles of my invention are equally applicable to the production of core boxes, for example, and the term pattern as used herein and in the claims is intended to include all such similar molding means. While the grooves formed to receive the metal llet will desirably be underout as shown, this is not always absolutely essential nor is it always essential that the edge of the pattern piece overlie one edge cf such groove. A considerably stronger lock for the fillet is, however, obtained by following such latter practice, and its use is much preferred.

The pattern (including pattern plate) may comprise a plurality of separate parts joined together and thereby forming reentrant angles in which I cast my novel fillet. Since such fillet is thus formed in situ, a very perfect fit is obtained and the mechanical interlock is permanently tight. The pattern parts may be of wood or metal, or combinations of the same, and changes may be made in my new patterns with a minimum of trouble and expense. The low temperature metal alloy is easy to handle and does no damage to the wooden parts to which the fillet is applied.

As above indicated, a preferred adhesive for the sprayed-on metal coating is a rubber latexsynthetic resin glue, and I have found a glue marketed under the trade-name Liqui-Plastic by Wellman Products Company, Cleveland, Ohio, to be excellent for the purpose. Under some circumstances the use of an adhesive may notl be absolutely essential although it will ordinarily be highly desirable.

Other modes of lapplying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In the manufacture of patterns for the production of sand molds and the like, the steps of routing out a groove in the surface of a fiat wooden pattern plate following the general peripheral contour of a pattern to be mounted thereon, such groove having undercut edges, mounting such pattern upon such plate with the edge of such pattern overlying the inner edge of such groove, thereby forming an inside corner angle between such pattern and plate, placing a flexible elongated member of circular cross-section in the angle between such pattern and plate and in contact with the same, such member having a radius equal to the radius of a desired fillet, securing such member in place with oil-base modelling clay, forming a pouring sprue of such clay for admission of molten metal behind such member to such groove, forming an air vent between such member and pattern diametrically opposite such sprue, pouring a sumcient quantity of an alloy of bismuth, lead, tin, and cadmium fully molten at F. in such sprue to ll such groove and form a metal llet, removing such clay and flexible member after hardening of such fillet, coating such pattern and pattern plate with a thin layer of a plastic adhesive containing rubber latex, and spraying a thin coating of the above-identied alloy on suchpattern and pattern plate after such adhesive has become tacky.

2. In the manufacture of patterns for the production of sand molds and the like, the steps of forming a groove having undercut edges in the `surface of a flat wooden pattern part following the contour of a smaller pattern part, mounting such smaller pattern part upon such first part with its edge overlying an edge of such groove 'but leaving a portion of the width of such groove exposed, removably securing an elongated member of circular cross-section having a radius equal to the desired fillet radius in the angle between such parts and in contact with the same, pouring a low melting metal alloy in `such groove and behind such elongated member to form such llet, removing such member after hardening of such fillet, coating such parts with a thin layer of a plastic adhesive containing rubber latex, and spraying a thin coating of low melting metal alloy on such parts after such adhesive has become tacky.

3. In combination with a wooden pattern plate and wooden pattern for foundry molding mounted thereon to form an inside corner angle therebetween, a metal fillet of low melting alloy and desired radius cast in the angle between plate and pattern, said fillet having an integral portion filling an undercut groove in the surface of such plate following the contour of such pattern with with such pattern overlying an edge of such groove, a thin hard plastic coating on the exposed surface of such plate, fillet and pattern, and a thin sprayed coating of a low melting alloy of bismuth, lead, tin, and cadmium on said rst coating.

4. A metal surfaced wooden pattern comprising a pattern part having a groove in its surface corresponding generally to the contour outline of a second pattern part, such groove having undercut edges, a second pattern part mounted on said ufirst part with its edge overlying an edge ofs'uchfg'roove, therehyiorrning Yan inside corner angle between such parte a metaillet @111.119 such groove andvforminga desired'radius in the angle between' Vsaid. parts, 'anfadhesive 4coatingon the exposed surface of'said parts' aridfnilet, and a thin'metalcoatng'adheredto said r'st Icoatlne.

5. A Vmetal surfaced V Wooden'pattern comprisin'fga pattern part 'having 'agroove in its surface corresponding Fgenerally to -the contour outline 4 of a v second pattern part, such"'groove having undercut edges, 'a secQnd pattern part'mounted. `0,11 saidrst part jvvithits edge'adjac'ent such groove, thereby forming an inside corner Yangle between such parts, a metal fillet filling such groove and forming a desired 'radius in theangle between said parts, means independent of said lletjoining said Vpattern parts together, anda thinmet'al coating adhered to the exposed surfaces of said Pattern partsand llet. y

`v6. A nietal surfacedwooden pattern 'comprising 'apattern part having a 'groove in jits snrface corresponding 'generallywto the contour outline'of a second pattern par' t, aJ second pattern part mounted on'sai'd r'st part with its edgeloverlyingan edge of such groove,`a metal viijllet lling suchgroove and forming a desired radius in the anglejbetween said parts, means independent of said fillet joining said pattern parts together,

andja thin metalcoating adhered to the exposed surfaces of'said pattern parts and fillet.

7. In combination, a pattern part k having a groove in its surface corresponding generally to the contour outline of a second pattern part.

such groove lhaving.undercut Edges, a second patternw part mounted on said nrst part with its edge overlying an edge of such `r1C, QY\2, thereby forming an inside corner vangle between such parts, a metal fillet lling 'such groove and forming a desired radius in the .angle between said parts, said fillet `being thereby mechanically locked in place, and means independent of said llet joining the patternparts together.

8. In combination, a pattern part having a groove in its surface corresponding generally to the contour 'outline of a second pattern part, such groove having undercut edges, 'a second pattern part mounted on said rst part with its edge adjacent auch, elQve. thereby forming.. an maiden her angle between such Darts; a 'mtal llet' .ne suchgfroove and, ,forming a Ydesired radius 'in the angle betwen'said parts, said'llet being thereby.mechancallvflocked inplae, and means'independent of said fillet' joining the pattern ,partstQeether-- '9. .Anattern for use'rifoundrv moldingand the like 'having 'a groove in one pattern surface correspondingjgenerally 'to the contour outline of a 'second'p'attern surface, "such groovehavingundercut edges, said secqndjpattern surface overlying an ed'gebfisucngraove thereby' forming'an inside corner 'angle between suchsurfaoes, and a rnet'al fillet filling such groove and'formin'g'a desired'radius in the angle between said surfaces, saidv fillet being thereby mechanically locked in place.

KARL T. RINnERLiE.

A :REFERNCES CITED The refollowingdfreferences are of record inthe le of this patent: e

UNITED STATES PATENTS 972,473 isbr'idger et al. Oct. v11, 1910 1,050,201 Bellf, Jan. 14, 1913 1,303,430 Washburn e't al. May .13, 1919 1,438,949 Dean 1 Dee. 19, 1922 1,857,526 Burnifsh May 10, 1932 2,097,850 Wallace Nov. f2, 1937 2,280,864 s tosse1 Apr. 2s, -1942 2,351,919 Bright June 20, 1944 2,394,394 Mi11er 1 Feb. i5, V19216 2,479,598 Barber et al. Ag. 23, 1949 FOREIGN PATENTS `143,738 :Great Britain June 3, 192D

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