US2160645A - Foundry mold and the like - Google Patents

Description

May 30, 1939. w. w. COOPER 2,160,645

FOUNDRY MOLD AND THE LIKE Filed Juiy 2, 1957 PateatedMay 30,1939 .l

*PATENT oFFlcl.

v 2,160,645 Pomar Mom ANn'rnn una wmiim w'. cooper, naumburg, rs., signor to Bethlehem Steel Company, a corporation of Pennsylvania Application July z, 1937, serial No. 151,559

' s claim. (ci. zz-im fIhis invention relates to improvements in molds for; metal castings, and particularly to molds which are formed of a mixture of sand and a hydraulic cement.` y The casting of certain' metal shapes, such as pipes, whichV have flangedl or belled ends, is attended by kdiilicuities not met with in casting other shapes. When a lshape such as a pipe having flanged ends is cast, there is the danger l0 that in cooling and contracting, the anges will break oif, due to the great pressure exerted on them by the 'contraction of 'the main body of the casting. Attempts have been made in the past to avoid this difliculty by placing some sort of destructible insert, usually `combustible, in back of the anges. The hot metal'would destroy the insert, leavingvroom for longitudinal contraction of the casting.

Since the advent of sand and cement molds, this problem of breakage has been even more diiilcult to cope with. Sand and cement molds,

because of their great rigidity, oifer more resist-l ance to contraction than the sand or sand and clay molds of the prior art.

25 It is an object of this invention to construct a sand-cement mold for casting flanged and belled shapes which, while possessing the strength and economy of sand-cement,molds, will eliminate the danger of broken castings.

It is a further object to provide such a mold in which allowance is made for longitudinal contraction of a casting, and the amount of such allowance is governed by and varies with the force exerted by the flanged ends of a casting moving toward each other during contraction of the casting.

The novel features of my invention will be more fully understood from the following description and claims, taken with the drawing, in which Fig. 1 is a side plan view of a mold embodying my invention;

Fig. 2 is a section along the line 2-2 of Fig. 1 and Fig. 3 is a section similar to Fig. 2, showing a modification.

As is well known to those versed in the art,

sand-cement Vmolds do not require the heavy.

flasks needed to support ordinary sand molds. That is, the sand-cement mold may be built up with boxes and patterns, and after the cement has set the mold has sumcient structural strength to stand by itself without external support.

Referring now to the drawing, I have shown a mold intended for use in casting shapes, whether solid or hollow, having a general I-shape. The

mold I0 comprises an upper half and a lower half, each of which is made up of end portions II and I2 and intermediate portions I3. Referring to Figs. 1 and 2, it will be seen that the intermediate portions or inserts I3 are of a gen- 5 eral wedge-shape, and that the faces I4 of end portions II and I2 are disposed at an angle to coincide with and t against the faces I5 of ln serts I8. y

Molten metal is poured into mold III in any of -10 the usual ways, as through runners I 6. Mold III may also be provided with the usual heads or risers I1. As the` molten'metal cools and solidii'les, it` begins to contract longitudinally, and great pressure is exerted on anges I8 of casting l5 I9. Were mold II) of solid, one piece construction considerable strain would be put on the ilanges I8, and in many cases flanges I8 would be broken off from the main body of the casting. However, with my construction, the faces I4 and 20 I5 are slidably movable relative toeach other. As the casting contracts, the pressure or pull exterted on anges I8 will tend to draw end portions I I and I2 ofmold III towards each other. The shape of insert I3 permits such a movement 25 to take place, insert I3 being wedged or squeezed out by end portions I I and I2, as shown in dotted lines in Fig. 2. This permits the casting to contract as far as necessary without unduly straining its flanges. In some cases it may be desirable 30 to remove insert I3 as soon as lthe casting has solidied. 'I'his of course may be done readily, as thev shape of the insert permits its removal without danger of binding between the end portions, and without disturbing the other parts of 35 the mold.

In the modification of my invention shown in Fig. '3, instead of making inserts 28 of a wedge shape, I construct them with straight or vertical faces 2l. However, inserts 20 will be constructed 40 of thin shells 20' of sand andv cement, their interiors 20" being of loose plain sand. As the end portions 22 and 23 of mold 24 are drawn towards each other by the force of the contracting casting, inserts 20 will be crushed, the material of the 45 inserts 20 being moved or forced outwardly, and thus allowing the casting to contract without any undue force being exerted upon the casting.

The advantages of this type mold will be apparent to any one skilled in foundry practice. 50

The danger of cracked castings is great1y.re duced. It is not necessary to gauge beforehand what allowance must be made for contraction. My construction is such that just as much allowance will be made for contraction as is need- 55 ed-no more and no less--for the simple reason that'the amount of contraction allowance is determined directly by the casting itself in contracting. In short, my invention consists in a multi-part mold for casting metal articles, in which the intermediate portions of the mold are automatically dispiaceable in whole or in part to -permit free contraction of the casting.

While I have described my invention in considerable detail, I do not wish to be limited to the exact and speciilc details thereof as herein described, as it will be apparent that numerous variations thereof might be constructed `without departing from the 'spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters- Patent is:

1. A sand and cement mold for casting ilanged metal articles, said mold comprising end portions and intermediate portions, said end portions being adapted to move towards each other in response to' pressure exerted by the flanges during contraction of a. casting, said intermediate portions being movable relative-to said end portions to permit movement of said end portions towards each other.

2. A sand and cement mold for casting anged. metal articles, said mold' comprising end portions and wedge-shaped intermediate portions, said intermediate portions being adapted to .be displaced by movement of said end portions towards each other during contraction of a casting.

3..A sand and cement foundry moid i'or casting metal ai'ticles, said mold comprising end portions and wedged-shaped intermediate portions,

said intermediate portions being automatically responsive to pressure ezxerted by contraction of a casting to permit movement oi' said end' portions towards each other during contraction of a casting. ,v

4. A sand and cement foundry mold for casting metal articles, said mold comprising end portions and wedge-shaped intermediate por'- tions, said intermediate portions being displaceable at least in part to permit movement of said end portions towards each other responsive to pressure exerted by contraction of a casting.

5. A sand and coment mold for casting flanged metal articles comprising an upper portion and a lower portion, each of said portions comprisi118 two end sections and an intermediate section, each oi said end sections having one face inclined towards the center line of the mold, said intermediate section having two inclined faces registering with the inclined faces o! said end sections, said intermediate section and said end sections being slidably movable relative to each other in response to pressure exerted by contraction of a casting.

6. A sand and cement mold for casting flanged metal articles comprising an upper portion and a lower portion, each of said portionscomprising two end sections and an intermediate section, said endsections being movable towards each other in response to pressure exerted by contraction oi a casting, said intermediate section being slidably movable relative to said end sections to permit movement o! said end sections toward each other.

WILIJAM W. COOPER.

Images