US2079393A - Core structure - Google Patents

Description

May 4, 1937. BEN 2,079,393 CORE STRUCTURE Filed July 20, 1935 s Sheets-Sheet 3 a?! 1937. F. H. BENGE 2,079,393

CORE STRUCTURE Filed July 20, ,1955 5 Sheets-Sheet 2 EwerzZr Patented May 4, 1937 tartar orrice tinental-Diamond Fibre Company,

Newark,

DeL, a, corporation of Delaware Application July 20, 1935, Serial No. 32,459

12 Claims. (CI. 18-45) This invention relates to hollow articles and, more particularly, to such articles as pipes, pipe fittings and the like. In my prior Patent No. 2,003,232, granted May 23, 1935, there is disclosed and claimed a method of making an article of this class which is composed of fibrous ma terial and an associated binder, and the walls of which form a contiguous, homogeneous, coherent structure free of lines or planes of cleavage and uniformly massed by intermingling and coherence of its constituent fibrous material and the binder. In the method of the said patent, the desired article is formed by first p-reforming at least one part of the article with loose, ragged edges and then building up the remainder of the complete preform of the article in a manner to cause intermingling of the fibrous pieces at the said loose ragged edges so that an article of the character above mentioned is obtained. In my copending application, Serial No. 19,276, filed May 1, 1935, the improved article obtained by the method of my said patent is claimed.

The present invention has for its principal ob ject the provision of a novel method of forming the said article, which method is. in the nature of an improvement over that of my prior patent above mentioned. Ihe present method eliminates the necessity of preiorming the article or any part thereof, which is required in the method of my said patent. By means of the present method, it is possible to mold the material of which the article is to be formed directly about a core, at the same time obtaining uniform distribution and density of the material about the core so that the finished product has the desired characteristics above mentioned. It has been the practice in the past to use a fusible core in the molding of hollow articles, but in all prior methods of which I am aware, it has been necessary to preform parts of the desired article, and in the practice of all such prior methods, except that of my said prior patent, there have been obtained in the finished article undesirable lines or planes of cleavage at the junctiu'e of the preformed parts. This weal:-

ens the article and, in the case of an article such as a pipe fitting which is subjected to excessive stress at the threaded portions, the tendency is for the weakened article to fracture. This led to the invention disclosed in my said patent. By the present method, however, there is provided a novel method and apparatus and a novel knockdown core which conjunctively make practical the molding of the article about the core in a single operation and without the necessity of pre forming any part of the article.

Although the invention is applicable generally to the manufacture of hollow articles, since a pipe fitting is a very good example of the articles which may be made by practicing the invention, I have chosen to illustrate and describe the invention in detail with reference to a T pipe fitting. The invention may be clearly understood, therefore, by reference to the accompanying drawings, in which Fig. l is a perspective view of one of the core parts employed in accordance with the invention;

Fig. 2 is a perspective view of another of the core parts;

Fig. 3 is a perspective View of still another core part;

Fig. 4 is a perspective view of a further core part;

Fig. 5 is a perspective View of one of the parts of the core mold;

Fig. 6 is a sectional view taken through the core H mold and the assembled core therein;

Fig. l is a similar view showing the core after completion thereof;

Fig. 8 is a transverse sectional view taken along line 8-8 of Fig. '7;

Fig. 9 is a perspective view of the completed core;

Fig. 10 is a sectional view of the final mold with the complete core therein illustrating the molding method; and

Fig. 11 is a similar view illustrating the method at a later stage.

The present invention contemplates broadly the use of any fibrous material and an associated binder which may be found suitable. Preferably, however, small pieces of cotton base fabric impregnated with synthetic resin of the phenolic type and, more especially, phenol-formaldehyde resin is used. Other fibrous materials which are applicable for use are asbestos in fibre or paper form, wood pulp, paper, etc. The choice of the particular fibrous filling material will be guided in any instance by the use for which the article is intended. Where the greatest possible strength is the controlling factor, small pieces of fabric are employed. In any case where the finished article is to be subjected to corrosive action such as that of chemical action, there should be associated with the fibrous filling material sufiicient resin to protect the material from the corrosive action and to give a strong unitary article. In the case of cotton base fabric, there is preferably associated with the fabric approximately to of resin. The cotton fabric is preferably the resinimpregnated waste material resulting from the manufacture of laminated! products, out into suitable size. For example, the resin-impregnated fibrous pieces may vary widely in size from A; inch at the smallest Width up to one inch at the greatest width. If in a particular instance the amount of resin associated with the fibrous filling material is not sufficient to bring the resin content up to the desired amount, powdered resin in sufiicient amounts may be added. Regardless of the type of fibrous filler, the resin content of the finished article is preferably in the neighborhood of 45% to 50%.

The type of binder most applicable is a synthetic resin either of the thermo-settin'g or thermo-plastic type. The particular binder chosen is governed by the use for which the article is intended, and in the case of pipes or pipe fittings used to transport corrosive material, a binder may be used which is chemically inert to the material to be transported. While phenol-formaldehyde resins are preferable for the transportation of acids, polybasic-acid-polyhydric-alcohol and urea-formaldehyde resins are applicable for use for special purposes. Anilineformaldehyde resins of the infusible thermoplastic type are especially applicable for the transportation of alkaline solutions. In making the article of the present invention, the temperature, pressure and time conditions are selected which are applicable in conjunction with the particular resin. Hereinafter the invention will be described with the use of phenol-formaldehyde resins as illustrative.

As well known, phenolic resins exist in an initial or soluble and fusible stage and in a final or insoluble and infusible stage. The conversion of the resin from the initial to the final stage may be effected by heat or by heat and pressure.

Referring now to the drawings, Figs. 1 to 4 show the parts of a knock-down core which may be employed in accordance with the present invention in the manufacture of a T pipe fitting.

The parts are shown in such relation to one another that their assembly may be clearly envisioned from the following description. The parts shown in these figures are all formed of some relatively infusible metal or alloy, such as steel. In Fig. 1, there is illustrated a body part I and in Fig. 2, there is illustrated a second body part 2, these parts being adapted to be brought into cooperative relation with one another to for i a T-shaped core body of the proper shape and size for the particular T fitting. The main portion of the body part I is preferably provided with longitudinal corrugations 3 on its outer surface and this portion is of smaller dimension than the desired completed core for a reason which will appear hereinafter. The opposed ends 4 of the body part I are of smaller diameter than the main portion and these ends are adapted to support the threaded,

parts 5, one of which is shown in Fig. 4, it being understood that two of these parts are provided, one for each of the ends *4. The parts 5 are adapted to fit slidably and snugly over the ends t of the body part i. The main portion 6 of each of the threaded parts 5 is threaded as illustrated and conforms in contour with the threaded surface which it is desired to provide internally of the ends of the desired finished product. These threaded parts 5 are each provided with an integral nut portion '1 bymeans oi which the parts may be removed from the acrea e finished article as will be explained hereinafter.

The second body part 2 has one end 8 formed as illustrated to cooperate with the serrated portion 3 of the body part I. To this end, the end 8 of the body part 2 is provided with serrations 9 which are complementary to the serrations 4 so that the two body parts may be interlocked one with another as seen in Fig. 8. It will be seen that the body part 2 may be moved longitudinally of the body part I to obtain the proper relative positions of the two body parts. The portion 8 of the body part 2 is of smaller dimension than the desired complete core for a reason which will be explained presently.

The other end In of the body part 2 is of small diameter and is adapted to receive a threaded part H which is similar in all respects to the threaded parts 5 and is provided to form the third threaded portion of the desired T fitting.

' Referring now to Figs. 5 to 3, in Fig. 5 there is illustrated one of the parts H of a two-part mold, the mold being shown in assembled form in Fig. 8 which shows the other part l3. These two mold parts are similar and are provided with interlocking pins and recesses. The mold part l2 is provided with the tapered pins l4, while the mold part It is provided with recesses 15 adapted to receive the pins Hi. The mold part I3 is also provided with an opening l5 through which fused metal may be poured as described hereinafter.

It will be seen from Fig. 5 that the mold parts; are provided with recesses I? which are adapted to receive the threaded portions of the threadedgl core parts 5 and H, and there are also provided"; recesses l8 which are adapted to receive the nut: portions 1 of the threaded core parts and recesses L! which are adapted to receive the extending;- ends 4 and ill of the body parts of the core.

In practicing the method of the invention, the;

first step is to assemble the core parts illustlzatedi in Figs. 1 to 4 and to place these assembled parts; in the core mold. Obviously, this may be done; by first placing the assembled parts in one-half. of the mold, for example the mold part I! shown; in Fig. 5, and then applying the other half of? the mold. It will be understood that the; two

mold parts may be secured tightly together by/ any suitable means such as a clamp. The; core.- mold with the assembled core parts therein is; shown in Fig. 6. The internal contour ofgthercoreg mold about the portions 3 and 8 of the, core-parts: I and 2 conforms in shape with the; desired: completed core.

A metal of relatively low melting point, for example 450 to 500 R, such as lead, is then poured through the opening l6 into the space 20 surrounding the portions 3 and 8 of the solid core parts. When allowed to harden, this metal builds up the body of the core to the desired shape and dimension and, at the same time, it secures the assembled core parts together. The serrations of the portion 3 hold the lead or like metal securely and prevent this relatively soft metal from sliding off the core parts. The com pleted core prior to removal from the core mold is shown in Fig. 7, the molded or cast metal being I completed core is removed. The completed core is shown, after removal from the mold, in Fig. 9. It will be seen thatthis core conforms in shape with the internal surface or surfaces desired in the finished article.

Referring now to Figs. and 11, there is illustrated the molding of the desired article which, of course, constitutes the essential part of the invention. The mold used for this purpose may comprise a hollow ring or outer casing 22 and a split tapered mold 23, the complementary parts of which are adapted to fit snugly within the ring or casing 22 in Well-known manner. The two part mold 23 is adapted to receive the completed core, as clearly illustrated, and when the core is in place in the mold, there is provided a space 2 which conforms in shape and dimension with the walls of the desired article. It will be seen that the ends 4 of the solid core part I, and the nut portions 1 of the parts 5, are seated snugly in recesses in the mold 23. Thus the end portions of the solid core part I serve to support the completed core in the mold, maintaining the core in proper position throughout the molding recess.

A sleeve 25 is placed over the extended end Iii thus forming an annular reservoir 26 which communicates through a narrow annular opening 27 with the channel-like space 2 3. An annular plug 28 is adapted to fit snugly and slidably into the annular reservoir 25.

Following the method of the invention, after the completed core has been assembled in the mold as illustrated in Fig. 10, the material of which the article is to be formed is placed in the reservoir 26. In the preferred form of the invention, this material may consist of small resin-impregnated fibrous pieces as above mentioned. It will be understood that the resinous binder is in its initial soluble and fusible stage. The resinimpregnated pieces may be placed in the reservoir 26 until the said reservoir is substantially filled. The reservoir may be of such size as to hold sufiicient material to completely form the desired article when it is filled with such material.

Pressure is now applied to the material in the reservoir by means of the annular plug 28 and the material is thus caused to flow through the annular opening 2'! into the space 25 about the core. The restricted annular opening 21 allows only a low rate of flow of material into the space 24 and thus the process comprises a slow flowing of the material into the space 24 and around the core. In this manner, the material is distributed evenly about the core, the small fibrous pieces being interspersed or intermingled with one another, and there results a homogeneous wall structure of even density, as shown in Fig. 11. It is important to note that the provision of the reservoir 26 and the restricted opening 21 enables the successful attainment of the desired object. By the use of these features and the particular core structure, it is possible to completely mold the material about the core in the desired manner without distorting the core. By the use of solid core parts, as above described, the core is strengthened or reinforced and is capable of withstanding the pressure to which it is subjected. At the same time, however, the stress or force to which the core is subjected and which tends to distort the core is maintained at a minimum by reason of the particular method employed.

After the article is completely molded about the core, as shown in Fig. 11, the conversion of the resin to its final or insoluble and infusible stage may be efiected by applying heat in conjunction with the pressure of the mold. The

temperature will depend upon the mold pressure and the time of the conversion process or vice versa, but in general a temperature of about 350 F. will be applied until the phenol-formaldehyde resin is completely cured. Of course, in any case the temperature should not rise to the melting point of the fusible metal of the core. It will be understood, too, that the heating step will vary with various binders that might be used. Preferably, the outer casing 22 is provided with a steam jacket 29 having pipes 30 leading thereto by which the heating medium may be applied. In this manner, the entire mold is very readily heated to the desired temperature. Inasmuch as the mold is of substantial height, it would be impractical to depend upon traversal of the heat by conductivity from one part of the mold to another and it is, therefore, desirable to employ a heating jacket as illustrated.

After the binder has been completely cured and the finished article has thus been produced, the said article with the core therein is removed from the mold. The threaded parts 5 and Il may be readily removed by unscrewing them from the finished article by means of a wrench or the like applied to the nut portions 1. Sufficient heat is then applied to the fusible metal 2| to melt the same. This may be done by simply directing a torch flame onto the fusible metal. This frees the other solid parts of the core and enables their removal from the finished article. It will be seen that the solid core parts, as well as the fusible metal, may be used repeatedly in the manufacture of the desired article.

By means of this method, an article is produced having the desired characteristics above mentioned. It will be seen that the finished article requires no machining or like operation since the article is formed in its entirety including the threaded portions thereof. It will be seen also that the method is simple and inexpensive. It will be understood, of course, that the invention is not limited by the present disclosure but is susceptible to such variations 0r modifications as may occur to persons skilled in the art.

I claim:

1. In a core structure for use in the molding of hollow articles, such as pipe fittings, an inner core part formed of relatively infusible material,

an outer core part formed of similar material re- 1 movably carried upon a portion of said inner part and having an exterior contour similar to the internal surface desired on a portion of said article, and a body formed of relatively fusible material surrounding another portion of said inner part and securing said outer part on said inner part, said body having an exterior surface similar to the interior surface desired on another portion of said article.

2. In a core structure for use in the molding of hollow articles, such as pipe fittings, an inner core part formed of relatively infusible material and having a portion with a fluted surface, an outer core part formed of similar material removably carried upon another portion of said least one internally threaded end, an inner core part formed of relatively infusible material, an outer core part formed of similar material removably carried upon an end portion of said inner part and having an exterior threaded contour similar to the internal threaded surface desired at the end of said article, and a body formed of relatively fusible material surrounding another portion of said inner part and securing said outer part on said inner part, said body having an exterior surface similar to the interior surface desired on another portion of said article.

4. In a core structure for use in the molding of hollow articles, such as pipe fittings, an inner core part formed of relatively infusible material, outer core parts formed of similar material removably carried upon the end portions of said inner part, each of said outer .parts having an exterior contour similar to the internal surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding the intermediate portion of said inner part and securing said outer parts on said inner part, said body having an exterior surface similar to the interior surface desired on an intermediate portion of said article.

6. In a core structure for use in the molding of hollow articles, such as pipe fittings, an inner core part formed of relatively infusible material, outer core parts formed of similar material removably carried upon the end portions of said inner part With the ends of said inner part ex tending beyond said outer parts, each of said outer parts having an exterior contour similar to the internal surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding the intermediate portion of said inner part and securing said outer parts on said inner part, said body having an exterior surface similar to the interior surface desired on an intermediate portion of said article.

6. In a core structure for use in the molding of hollow articles, such as pipe fittings, an inner core part formed of relatively infusible material and having a fluted intermediate portion, outer core parts formed of similar material removably carried upon the end portions of said inner part, each of said outer parts having an exterior contour similarto the internal surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding the fluted portion of said inner part and securing said outer parts on said inner part, said body having an exterior surface similar to the interior surface desired on an intermediate portion of said article.

7, In a core structure for use in the molding of hollow articles, such as pipe fittings, having internally threaded ends, an inner core part formed of relatively infusible material, outer core parts formed of similar material removably carried upon the end portions of said inner part, each of said outer parts having an exterior threaded contour similar to the internal threaded surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding the intermediate portion of said inner part and securing said outer parts on said inner part, said body having an exterior surface similar to the interior surface desired on an intermediate portion of said article.

8. A core structure for use in the molding of hollow articles, such as T pipe fittings, comprising a plurality of complementary inner core parts formed of relatively infusible material, a plurality of outer core parts formed of similar material removably carried upon the end portions of said innerparts, each of said outer parts having an exterior contour similar to the internal surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding the intermediate portions of said inner parts and securing the various parts together as an integral core, said body having an exterior surface similar to the interior surface desired on the intermediate portion of said article. 7 Q

9. A core structure for use in the molding of hollow articles, such as T pipe fittings, comprising a plurality of interlocking complementary iner core parts formed of relatively infusible ma-. terial, at least one of said parts having an intermediate fluted surface, a lurality of outer core end portionof said article, and a body formed of relatively fusible material surrounding the intermediate portions of said inner parts andfse curing the various parts together as an integral core, said body having an exterior surface similar to the interior surface desired on the intermediate portion of said article. i 10. A core structure for use in the moldingof hollow articles, such as T pipe fittings, comprising a pair of interlocking complementary inner core parts formed of relatively infusible material and arranged at right angles to one another, at least one of said parts having an intermediate fluted surface, a plurality of outer core parts formed of similar material removably carried upon the end portions of said inner parts, each of said outer parts having an exterior contour similar to the internal surface desired on an end portion of said article, and a body formed of relatively fusible material surrounding .the intermediate portions of said inner parts and securing the various parts together as an integral core, said body having an exterior surface similar to the interior surface desired on the intermediate portion of said article. j v 11. In a core structure for use in the molding of hollow articles, such as pipe fittings, having at least one internally threaded portion, at least one core part formed of relatively infusible material and having an exterior threaded contour similar to the internal threaded surface desired on said article, and a body formed oflrelatively fusible material secured to said part and having an exterior surface contour complementary to said threaded contour and similar to the internal surface desired on another portion of said article. 12. In a core structure for use in the molding of hollow articles, such-as pipe fittings, having a plurality of internally threaded portions, a plurality of core parts formed of relatively infusible material and having exterior threaded contours similar to the internal threaded surfaces desired on said article, and a body formed of relatively fusible material securing said parts together and having an exterior surface contour complementary to said threaded contours and similar to the internal surface desired on another portion of said article.

FRANK H. BENGE.

Images