US2241996A - Mold - Google Patents

Description

I master surface.

I negative reproductions could e obtained the de- Patented May 13, 1941 UNiTED- STATES PATENT OFFICE MOLD Herbert S. Ingham, Jamaica, N. Y., assignor to Metalllzing Engineering Company, Inc.,'Long Island City, N. Y., a corporation of New Jersey Application January 31, 1940, Serial No. 316,581

1 Claim.

This invention relates to new and useful improvements in molds.

It is possible to make metal molds by spraying.

Metal spraying is carried out as a rule by the use of metal spray guns, 1. e., devices by which 'metal is fed to a heating zone and from which zone metal particles, at least some of which are molten or in a heat plastic condition, are propelled against the surface of a suitable object by a blast of air or other gas. Spray metal molds may be made for instance by first preparing a suitable master, spraying the master with metal in a manner understood in the art to produce a separable spray metal coating on the same and thereafter separating the spray metal coating from the master. A spray metal mold thus comprises a spray metal mold shell and a spray metal mold surface, the latter carrying in negative the design of the master surface to which it was applied. In the spraying of metal by means of a fects attending the spraying at an angle of impingement of lessthan approximately 30 would render the mold projections weak and cracked.

I have discovered that satisfactory spraymetal molds carrying relatively narrow and deep projections as'a constituent part of their-mold surface design may be obtained by providing the.

mold shell with one or more suitable substantially rigid inserts extending to the mold surface so as to form projections thereon as an integral constituent part of the design of the mold surface. In accordance with my invention I first produce for the comparatively narrow and deep crevices of the master (1. e., a substantially accurate dupllcateof an object or part of an ob- Ject to be reproduced) suitable inserts constitutmetal spray gun, ideal spraying conditions are particles of thusly appliedspray metal coatings is not very at. In most cases an angle of approximately 30 at which the particles impinge upon the surface sprayed is the safe limit for the procurement of a satisfactory spray metal coating. When spraying into relatively deep narrow crevices it is only possible to satisfactorily fill the same with spray metal if the surface see- 7 tions of the crevices adjacent the deepest point of such crevices can'be reached by the spray metal particles at an angle of impingement of at least 30 with said surface sections. In the production of spray metal molds, therefore, if the master design includes deep, narrow crevices, holes or the like, which in their relation of depth ing substantially accurate negatives of these crevices and fitting substantially snugly into the same. The inserts are so made that, when'placed into the crevices of the master, they will protrude therefrom. In practicing my invention, the inserts are placed into the corresponding crevices of the master design whereupon the mold metal is sprayed onto the surface of the insert fitted master. The protruding sections of the inserts are preferably roughened, dovetailed, keyed or otherwise treated or constructedto improve the anchorage of the same in the spray metal. After a spray'metal shell of suitablethickness is formed the same is separated from the master and the mold thusly obtained now possesses as an integral part of its projections. V

In the followinga specific embodiment of my invention is set forth by way of example and not by way of limitation and the invention will be more fully understood from the description therertlif read in conjunction with the drawing in whic Fig. 1 is a cross section through an article to be reproduced; I

Fig. 2 shows a cross section through a master of the article shown in Fig. 1 having a recess fitted insertpartly imbedded in a coating of spray metal;

and

. Fig. 3 illustrates 'a cross section through the finished mold; and

to width will not permit the spraying of their deeper portions except at an angle smaller than that required to procure a satisfactory spray metal coating, it is practically impossible to obtain accurate negative reproductions of the Even if substantially accurate Fig. is a cross section through a finished mold having multiple inserts.

In the drawing l designates the article to be reproduced and having as part of its surface design a. narrow and deep crevice 2. A master 3', in

, the form of a substantially accurate duplicate of the article I, is provided with a-suitable insert 4 fitting substantially accurately the contours of surface the desired narrow and deep the design crevice 5. The surface roughened pro- ,truding end 6 of the insert {is imbedded in the spray metal coating i applied in a manner well known inthe metal spraying art .to produce a separable mold shell by means of a gas-blast type spray gun schematically indicated at 8. After separation of the spray metal shell from the master, the former may be suitably machined to represent the finished mold 9 shown in. Fig. 3, possessing the solid metal insert d as an integral part of its surface.

It is of course possible to provide for multiple inserts and such multiple insert mold is for instance illustrated in Fig. 4 in which the machined spray metal mold in has the insert 1! dove-tailed at l2 and the insert 13 roughened at Id.

The material of the master may be any suit?- able metallic or non-metallic material provided the same lends itself to be suitably separated from the spray metal coating thereto applied in accordance with vwell known practices, 'I prefer, however, to use a metal master.

The material of the inserts may be any suitable metallic or non-metallic material. I prefer a material having a high tensile and transverse loading strength. Metal inserts are particularly adapted for use in connection'with my invention.

Depending upon the material of the master, the separation of thevspray metal shell therefrom may be effected in numerous ways. Where the master States'patent to Wm. .0. Reid, No. 2,171,599. If

the master comprises a non-metallic material its separation from the spray metal shell may be accomplished in most cases by suitable stripping from the master.

tion, a master of the article to be reproduced, it

is possible and often of advantage to use the original article itself as a master and where therefore the term master or such equivalent expression is used herein, it is intended to mean any positive of an article to be duplicated irrespective of whether such positive is the original article itself or a substantial duplicate thereof.

The foregoing specific description is for pur poses of illustration and not of limitation, and it is therefore my intention that the invention be limited only by the appended claim or its equivalent wherein I have endeavored to claim broadly all inherent novelty.

I claim:

Method of making a spray metal mold having at least one relatively narrow and deep projection as an integral part of the mold surface, which comprises placing into a relatively narrow and deep crevice on a master surface, which crevice substantially corresponds in configurati'onto the relatively narrow and deep mold projections desired to be obtained, a substantially rigid insert in part substantially fitting said crevice and in part protruding therefrom, spraying metal onto the insert fitted master until a spray metal shell has formed thereon and removing said shell and imbedded insert to recover-a spray metal mold having said insert anchored in said shell and extending to the mold surface to form a relatively narrow and deep projection thereon as an integral constituent part .of said mold surface.

I-ERBmT S. INGHAM;

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