US3283375A

US3283375A - Method and apparatus for casting tubular members embodying flat plane surfaced flanges, and product

Info

Publication number: US3283375A
Application number: US455920A
Authority: US
Inventors: Bert M Campbell; George B Miller; Earle W Deeble
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-05-14
Filing date: 1965-05-14
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08

Description

Nov. 8, 1966 B. M. CAMPBELL ETAL 3,233,375

METHOD AND APPARATUS FOR CASTING TUBULAR MEMBERS EMBODYING FLAT PLANE SURFACED FLANGES, AND PRODUCT 2 Sheets$heet 1 Filed May 14, 1965 L y M 5., PMEN MM a mw u .Bmw. 0, MM W25 "M m 1966 BhM. CAMPBELL ETAL 3,283,375

METHOD AND APPARATUS FOR CASTING TUBULAR MEMBERS EMBODYING FLAT PLANE SURFACED FLANGES, AND PRODUCT Filed May 14, 1965 2 Sheets-Sheet 2 17 154236 45 E; 6'. f x I M d 8527M. CAMPBELL GEO/P65 3. 44/45? E4245 W [755545 .Z/VVEA/TOES.

M zf WM United States Patent METHOD AND APPARATUS FOR CASTING TUBU- LAR MEMBERS EMBGDYING FLAT PLANE SUR- FACED FLANGES, AND PRODUCT Bert M. Campbell, Lynwood, George B. Miller, Bellflower, and Earle W. Deeble, Fullerton, Calif., assignors to Frank E. Dayton, doing business as Dayton Foundry, South Gate, Calif.

Filed May 14, 1965, Ser. No. 455,920 7 Claims. (Cl. 22-131) This invention relates to the casting of tubular members, as for example, T pipe fittings, which embody at least one terminal flange for attachment to a mating flange or other connection.

Heretofore tubular members of this character were formed by the conventional sand casting or permanent mold processes and necessarily came out of the mold with a draft or taper on the face as well as on the back of the flange. This resulted from the fact that in producing a cavity by ramming green sand around a pattern in the drag and cope, a pattern with a plane parallel surfaced flange cannot be withdrawn from the sand without damaging the cavity surface. In the case of permanent molds, it is diflicult, if not impossible, to withdraw the cast product unless it has a draft.

The objection to having the flange come out of the mold with a draft is twofold. First, the face in most cases has to be machined down into a flat plane, and in many cases should be formed with annular serrations, which also have to be machined in; and, second, when a bolt is used to secure the flange to a mating connection the head of the bolt or the nut will not lie flat against the tapered back surface of the flange and must either be wedged against a fraction of the surface or a tapered washer be employed, or the back surface be machined down.

It is a primary object of the invention to provide a method and apparatus for casting tubular members, as for example, a T pipe fitting, with one or more flanges thereon, wherein at least the face, and preferably both surfaces of the flange, are in finished condition, namely, lying in flat planes and parallel to one another, and if desired with annular serrations on the front surface.

This is accomplished basically by employing what may be designated a secondary (flange forming) mold within a primary mold. The secondary mold is formed with the required external draft so that the pattern which has initially prepared the cavity may be readily removed from the green sand, and the secondary mold readily inserted, and the secondary mold contains the cavity for the pipe flange in its finished form. The secondary mold is associated with and is for practical purposes a part of a core body, and is made of a material, like that of the remainder of the core body, which will break down after the poured metal has solidified. Shell sand is a good example of such material, being sand held together by a phenolic resin binder, and baked after forming.

In the drawings:

FIGURE 1 is a top plan view partly in section of a T pipe fitting made according to the invention;

FIGURE 2 is a side elevation of the same;

FIGURE 3 is a top plan view of a core body assembly which includes a secondary (flange forming) mold here tofore referred to;

FIGURE 4 is a top plan view of the drag of the primary mold, and in which a cavity has been formed by a suitable pattern for reception of the core body assembly of FIGURE 3; the pattern need not be illustrated because it embodies an external configuration identical to the surface of the cavity;

FIGURE 5 is a top plan view of the drag of the primary mold shown in FIGURE 4, with the core body assembly of FIGURE 3 (shown in section) installed;

FIGURE 6 is a vertical section taken on the line 6-6 of FIGURE 5 showing the cope and drag of the primary mold assembled with the core body assembly in place, as in FIGURE 5; I

FIGURE 7 is an enlarged sectional view of the secondary mold;

FIGURE 8 is a fragmentary section taken on the line 88 of FIGURE 7;

FIGURE 9 is a fragmentary sectional view of the cast flange area of the pipe fitting, such as corresponds to the mold portion illustrated in the upper part of FIGURE 7.

By way of a preliminary summary, reference is made to FIGURE 6, showing a mold which is ready for a pouring operation, comprising a drag 10 and a cope 11. These make up a conventional flask 12 packed with green sand 14, and within the green sand the core body 15 reposes, which core body includes a secondary (flange forming) mold 16. The core body, including the secondary mold, is preferably formed of shell sand.

Molten metal is introduced through a sprue 17 and gate 17a to the space 18 between the core body and the inner surface 19 of cavity 19a which space continues into the secondary mold 16.

The shell sand of the core body withstands the heat of the molten metal for a time sufficient for the metal to set, and this shell sand thereafter breaks down due to a burning out of the phenolic resin binder, or at least one or nrlire of its components, and is of course readily remova e.

When the primary mold is broken and the resulting casting 20 (FIGURE 1) is removed, it is in the finished form illustrated in FIGURES 1 and 2, in which flange 21 incorporates flat plane parallel front surface 22 and rear surface 23, as well as serrations 24 and bolt holes 25- The steps preliminary to the pouring of the metal may be outlined as follows:

A pattern of any suitable material (not shown) but having the external configuration of the cavity 19:: illustratcd in FIGURE 4 is employed in the conventional manner to form this cavity in the drag and cope of the primary mold. The pattern embodies draft in the secondary mold as seen in the outline of the cavity.

The core body 15 embodies a T section 26 and the secondary mold 16. The T section may be made in a conventional manner by introducing shell sand into a suitable cavity and baking it. This T section 26 includes anchor plates 27 which co-operate to properly position the core body in the cavity 19a, a reduced diameter surface 28 to provide the space 18, and a plug 29 (preferably tapered) for receiving the secondary mold 16. This plug 29 is formed with an annular shoulder 30.

The secondary mold 16 which contributes one of the principal features of novelty of the invention, is made up of two

parts

31 and 32. They are formed separately of shell sand introduced into molds or forms of the proper internal configuration and are baked. Either before or after baking they are assembled by mutual engagement of interlocking

annular members

33 and 34.

The external configuration of the assembled

sections

31 and 32 is such as to fill the complementary portion of the cavity 19a and thus aid in properly positioning the entire core body in the cavity 19a. Internally the section 32 is formed with a hollow taper 32a which engages the plug 29 and it also has an annular shoulder 35 which stops against the shoulder 30.

The internal design of the

sections

31 and 32 is such as to mutually provide an annular cavity 36, preferably with grooves 37 to form serrations, and an annular cavity 38 which joins and is essentially a continuation of cavity 18. The cavity 36 includes opposite walls which are plane faced and parallel.

This cavity 36 enables molten metal to form the flange 3 21 without any machining or other alteration after removal from the mold.

In all cases where it is desired to provide bolt holes 25 through the flange 21, the secondary mold may include posts 40 (see FIGURES 7 and 8) around which the molten metal flows in the annular cavity 36.

An incident of the invention is the tapering of the external

annular surfaces

42 and 43 of the

sections

31 and 32 which make up the secondary mold. These in conjunction with the taper 32a on the section 32 enable an easy withdrawal of these'sections from the forms in which they are prepared.

The

sections

31 and 32 may be solid, as shown, or may be made hollow for lightness.

Reference to the various materials used in the molds and the core body are by way of example only and not of limitation. Various types and structures of. primary molds may be employed including permanent molds instead of sand type. It is obvious also that various materials may be utilized for the core body including the secondary mold. It is essential, however, that this core body assembly be sufliciently rigid and stable for handling, but susceptible of disintegration or easy destruction after the metal of the casting has set.

An important thing is the formation and utilization of what we have termed the secondary mold associated with and functioning as a part of the core body wherein taper or draft is shifted from the old form of tapered flanges to the external surface of the secondary mold, whereby the flanges of the tubular cast member come out in finished form with their front and rear surfaces in flat planes and parallel. The section 31 could be modified, if desired, to provide a taper on the rear surface of the flange, while still producing the flat plane front surface, Moreover, the invention can be practiced to form flanges with short necks, by utilizing a core body assembly made up of the secondary mold filled up in the center as by the plug 29 or equivalent.

Although we have herein shown and described our invention in what we have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the inventiomwhich is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent methods and apparatus.

What we claim as new and desire to secureby Letters Patent is:

1. Apparatus for casting tubular members with flanges thereon having as removed from the mold substantially flat plane front faces, said apparatus comprising a core body assembly embodying a peripherally drafted flange forming mold unit having a flange forming cavity therein with a substantially flat plane wall to define the front face of the flange, and a primary casting receptacle with a cavity therein conforming to the external size and shape of the flange forming mold unit and otherwise defining the outside surface of the tubular member to be cast which is not provided by said unit, the flange forming mold unit comprising complementary sections separately formed and when united having a parting line on a plane normal to the axis of the flange forming cavity.

2. An apparatus as defined in claim 1 in which the flange forming mold unit has a tapered hollow center and the core body assembly includes a T sect-ion in which the stem of the T is tapered and fits in the tapered hollow center of the flange forming mold unit.

3. An apparatus as defined in claim 1 in which posts are provided in the flange forming mold unit for casting bolt holes in the flange.

4. Apparatus for casting tubular members with flanges thereon having as removed from the mold substantially flat plane front faces, said apparatus comprising a core body assembly embodying one section generally defining the inside surface only of the tubular member to be cast, and a flange forming mold unit having a flange forming cavity constituted entirely within the unit with a first substantially flat plane wall to define the front face of the flange and a second wall spaced from the first to define the rear face of the flange, said mold unit being externally peripherally drafted and united with said one section, and, a primary casting receptacle with a cavity therein conforming in part to the external size and shaped the mold unit and snugly enclosing the latter and otherwise defining the outside surface of the tubular member to be cast which is not provided by said mold unit.

5. A destructible core body assembly for employment in the cavity of a primary mold to cast a tubular member embodying a flange with a substantially flat plane 1 front surface, said core body assembly comprising ,onem section generally defining the inside surface only of the tubular member to be cast, and a flange forming mold 1 unit having a flange forming cavity constituted entirely therein with a first substantially flat plane wall to define. the front face of the flange and a second wall spaced from a the first to define the rear face of the flange, said mold 1 unit being externally peripherally drafted and united with said one section, said assembly being formed of material which will retain its shape during pouring of molten metal but can be readily broken down metal solidifies.

6. A method of casting a tubular flanged member in which at least the front face of the flange is without any draft, comprising the steps of: forming a major cavity in a primary mold with a first part of the cavity defining the exterior surface of the tubular member excluding the flange, and a second part of the cavity wherein the flange is to be cast made substantially larger than the exterior of such flange and with a draft, forming a destructible core assembly with a first part to define the interior of the tubular portion and excluding the flange of the member to be cast, and a second part to provide a complete secondary cavity for the flange, shaping the exterior of the second part with a draft and of shape and size to snugly repose in the second part of the cavity in-the primary mold, uniting the two parts, placing the core assembly made up of the united parts in the major cavity, and introducing molten metal into the major cavity as restricted by the core assembly and into the secondary cavity.

7. A method of casting as defined in claim 6 in which the step of forming a major cavity in the primary mold is accomplished by preparing a pattern defining the exterior of a portion of the tubular member to be cast, and also the exterior of the second part of the core assembly; ramming sand around the patternin the drag and cope of a flask making up the primary mold, then separating the drag and cope .and removing the pattern.

References Cited by the Examiner UNITED STATES PATENTS J. SPENCER OVERHOLSER, Primary Examiner. E. MAR, Assistant Examiner.

when the cast

Claims

6. A METHOD OF CASTING A TUBULAR FLANGED MEMBER IN WHICH AT LEAST THE FRONT FACE OF THE FLANGE IS WITHOUT ANY DRAFT, COMPRISING THE STEPS OF: FORMING A MAJOR CAVITY IN A PRIMARY MOLD WITH A FIRST PART OF THE CAVITY DEFINING THE EXTERIOR SURFACE OF THE TUBULAR MEMBER EXCLUDING THE FLANGE, AND A SECOND PART OF THE CAVITY WHEREIN THE FLANGE IS TO BE CAST MADE SUBSTANTIALLY LARGER THAN THE EXTERIOR OF SUCH FLANGE AND WITH A DRAFT, FORMING A DESTRUCTIBLE CORE ASSEMBLY WITH A FIRST PART TO DEFINE THE INTERIOR OF THE TUBULAR PORTION AND EXCLUDING THE FLANGE OF THE MEMBER TO BE CAST, AND A SECOND PART TO PROVIDE A COMPLETE SECONDARY CAVITY FOR THE FLANGE, SHAPING THE EXTERIOR OF THE SECOND PART WITH A DRAFT AND OF SHAPE AND SIZE TO SNUGLY REPOSE IN THE SECOND PART OF THE CAVITY IN THE PRIMARY MOLD, UNITING THE TWO PARTS, PLACING THE CORE ASSEMBLY MADE UP OF THE UNITED PARTS IN THE MAJOR CAVITY, AND INTRODUCING MOLTEN METAL INTO THE MAJOR CAVITY AS RESTRICTED BY THE CORE ASSEMBLY AND INTO THE SECONDARY CAVITY.