US2418551A - Hollow article and method of making the same - Google Patents

Description

April 1947- L. L. GRENEKER v 2,418,551

HOLLOW ARTICLE AND METHOD OF MAKING THE SAME I Filed May 19, 1945 v 2 Sheets-Sheet l 5. &

1 INVENTOR.

April L. GRENEKER 2,418,551

HOLLOW ARTICLE AND METHOD OF MAKING THE SAME Filed May 19, 1945 2 Sheets-Sheet 2 x6244 z. MW

A 7 TOA /VA Y5 Patented Apr. 8, 1947 UNITED HOLLOW ARTICLE AND METHOD OF MAKING THE SAME Lillian L. Greneker, New York, N. Y.

Application May 19, 1945, Serial No. 594,773

Claims. 1

This invention relates to hollow articles and methods of making the same, and particularly to structures of display devices such as manikins, and methods of making the same.

The shells of such hollow articles are now usually made of papier mach in molds which cletermine the outside contour thereof. A method commonly used consists in building up a plurality of layers, usually four, of absorbent paper torn into pieces which are laid in overlapping relation against the walls of the mold and are pasted to one another. When the paper and paste has partially dried, the papier mach shell thus formed is removed from the mold and completely dried, after which the outside is smoothed and finished in various ways. This method of making the papier maoh shells of manikins or other articles is laborious; and it requires rather skilled labor, since otherwise soft and thin spots are likely to occur and cause trouble later in the finishing of the surface of the shell. Furthermore, such papier mach shells often change their forms during drying and thereafter with changes in atmospheric conditions.

The present invention results in the saving of labor, and makes possible the employment of less skilled labor than heretofore, in the making of the shells of manikins and other articles, and improves the quality thereof. The resulting product is a shell which is thin, strong and yet slightly flexible, and substantially free of warping and distortion during drying and thereafter.

The invention will be understood from the following description, taken in conjunction with the accompanying drawings, in which Fig. 1 is a perspective view of a part of a mold which has been partly lined with pieces of paper arranged in overlapping relation and pasted to one another; Fig. 2 is a plan View illustrating how the material for the sandwiches of plaster between sheet material may be made; Figs. 3 and 4 are plan views of sandwiches cut out of the material shown in Fig. 2; Fig. 5 is an enlarged sectional elevation on the line Ei-5 of Fig. 3; Fig. 6 is similar to Fig. 1, showing sandwiches of plaster between sheet material applied in overlapping relation to a portion of the paper lining of the mold; and Fig. 7 is a sectional elevation on an enlarged scale illustrating the structure of a shell made in accordance with the present invention.

In practicing the invention, the following materials are suitable: Heavy pulp-paper which is highly water absorbent; liquid paste of a kind commonly used for uniting pieces of paper; a sheet material, preferably a fabric such as cambric or cheesecloth which has been preshrunk, or paper or other sheet material having when wet a fair amount of strength; and a plaster of the slow-drying type, which may be mixed with water and which in drying does not shrink substantially. Such plasters are commonly sold in paint stores and by suppliers of building materials for, the patching of plastered walls and surface coatings, and it is commonly believed that they are generally composed of plaster of Paris, whiting and a retarder such as acetic acid. Such a, slow-drying plaster has been for many years and is still extensively sold under the name Spackle" by The Muralo Company, Inc., of Boston, Mass, Chicago, Ill., and Los Angeles, Calif.

Hollow articles of the kind to which the present invention relates are made in molds which determine the outside contours of the article. For example, the torso, head, arms and legs of manikins are separately made in molds'having two or more parts. It is customary to build up on the insides of the parts of such molds the material of which the shell of the article is made; and after the material has set the parts of the mold are removed and the shell is dried. Then the outside surface of the shell is subjected to various finishing treatments. The present invention relates only to the fabrication of the shell within the parts of the mold, and not to any treatments to which the shell is afterwards subjected.

In practicing the invention, the inside surfaces of the parts of the mold in which the article is to be formed are cleaned and prepared in the usual way. Then the inside surfaces of the mold are lined in the usual way with pieces of pulp paper torn from a sheet which has been moistened with water and smeared with paste on one side. These pieces of paper are laid in overlapping relation to one another over the inside surfaces of the mold parts, with the moist but pastefree side of the paper in contact with the mold, and the paste serves to unite the pieces of paper at their overlapping portions. Owing to their Wet condition, the pieces of paper are readily pressed against the convex and concave surfaces as well as the fiat surfaces of the mold, thereby insuring that the completed article will conform to the contours of the mold. In Fig. 1, a portion of the inside surface it of a mold part 52 is shown as having been partially lined with pieces of paper I4 laid in overlapping relation in the manner described. This paper lining serves to prevent the shell (the construction of which is hereinafter described) from sticking to the surfaces of the mold parts, and to provide the article with an outside surface to which the finishing treatments may be conveniently and satisfactorily applied.

After the inside surfaces of a mold part have been lined with pieces of paper in the manner above described, the rest of the shell is built up thereon according to the methods and constructions of the present invention, employing for that purpose sheet material and slow-drying laster, of the kinds hereinbefor described. In practicing the invention, sandwiches composed of wet plaster enclosed between pieces of a sheet material, such as a pre-shrunk fabric are employed. The material for such sandwiches is conveniently prepared by interposing wet plaster between layers of sheet material, preferably a pre-shrunk fabric, and pressing said layers of sheet material toward one another so as to expel air bubbles from the space between the layers of sheet material and give the wet plaster a substantially uniform thickness. This may be easily accomplished by laying a piece of sheet material on a flat surface, distributing over and brushing or rubbing into the sheet material a thin layer of liquid plaster, spreading over this wet plaster another piece of sheet material, and then rubbing the outside of the top sheet with the hands or any other suitable way so as to substantially eliminate creases and air bubbles and distribute the plaster substantially evenly in the space between the pieces of sheet material. This sandwich material is then cut up into strips, rectangular pieces and any other shapes by any suitable means such as a pair of shears. The sandwiches of wet plaster between layers of fabric or other suitable sheet material thus made should not be too large; and it has been found in the making of manikins that strips having a width of from two to three inches and rectangular pieces having dimensions of from two to three inches are most satisfactory. Fig. 2 shows layers of fabric l6 and I8 having wet plaster 28 interposed between them; and Figs. 3 and 4 show sandwiches in the form of strips 22 and squares 26 which have been cut from this composite material; As may be imagined, these sandwiches 22 and 24 are soggy, and easily distorted so that they conform to contours of any surfaces upon which they may be laid; although they are sufficiently coherent to permit handling and their use in the manner about to be described. Before applying the sandwiches to the paper-lined insides of the mold parts, the operator dips the sandwiches in a liquid mixture of the slow-drying plaster. Then the operator applies the plaster-smeared sandwiches to the paper lining of the mold parts, in overlapping relation to one another as shown in Figs. 6 and 7, and presses said sandwiches against the paper and against one another. During this operation, the sandwiches may be distorted as may be necessary or desirable in covering the various contours of the paper-covered mold surfaces. In using sandwiches in strip form, such as those shown at 22 in Fig. 3, it willscmetimes be found advantageous to apply them in pleats, particularly along the edges of the mold parts where strengthening of the shell may be desirable; and other ways of using the sandwiches to build up the composite shell structure will occur to the operator. The operator soon acquires the skill necessary to apply the sandwiches to the paper lining and press them into close contact with it throughout all of the contours of the paper lining. As will be obvious, this application of the plaster-smeared sandwiches to the paper results in producing portions of the shell where there are four fabric layers along the overlapping portions of adjacent sandwiches; and spots where there are eight layers of fabric where the corners of four adjacent sandwiches overlap. In effect, therefore, the shell is not only reinforced throughout by two layers of fabric, but i reinforced along various lines by four layers of fabric and is reinforced at spots by eight layers of fabric, which contributes greatly to the strength of the shell. Of course, the pattern just described is rather irregular, but that fact does not materially interfere with its effectiveness. The composite structure of paper, fabric and plaster which has just been described is more or less conventionally shown in cross section in Fig. 7 in which the overlapping pieces of paper are indicated at M, the sandwiches of fabric and plaster are indicated at 2t and the plaster which bonds the sandwiches to one another and to the paper pieces I4 is indicated at 26.

After a composite structure of paper pieces and sandwiches of fabric and plaster has been built up in this way, the shell is allowed to remain within the mold until it has set, which will require some hours. The parts of the mold are then separated, and the composite shell is removed and dried, after which it is ready for finishing in the usual way. This composite structure of paper, sheet material and plaster has the advantageous characteristics of drying without warping or distortion, and of being thin, light and strong, and yet slightly flexible around the openings in the various parts of a manikin or other article in which fittings must be inserted. Also, after drying, the shells of the hollow articles so made are substantially unaffected by changes in atmospheric conditions.

What is claimed is: v

1. A hollow article the shell of which comprises on its outside pieces of paper arranged in overlapping relation and pasted to one another, on its inside sandwiches of plaster enclosed between pieces of sheet material which sandwiches are in overlapping relation to one another, and plaster bonding the sandwiches together and to said paper.

2. A hollow article the shell of which comprises on its outside pieces of paper arranged in overlapping relation and pasted to one another, on its inside sandwiches of plaster enclosed between pieces of fabric which sandwiches are in overlapping relation to one another, and plaster bonding the sandwiches together and to said paper.

3. The method of making the shell of a hollow article, in a mold which determines the outside contours of the article, which includes lining the mold with pieces of paper arranged in overlapping relation to one another and pasting together the overlapping portions of said pieces of paper, and laying and pressing against said paper in overlapping relation to one another sandwiches of wet plaster enclosed between pieces of sheet material smeared externally with wet plaster, whereby said paper and pieces of sheet material are bonded together by the plaster when it dries;

4. The method of making the shell of a hollow article, in a mold which determines the outside contours of the article, which includes lining the mold with pieces of paper arranged in overlapping relation to one another and pastin together the overlapping portions of said pieces of paper, and laying and pressing against said paper in overlapping relation to one another, sandwiches of wet plaster enclosed between pieces of fabric smeared externally with wet plaster, whereby said paper and-pieces of fabric are bonded together by the plaster when it dries.

5. The method of making the shell of a hollow article, in a mold which determines the outside contours of the article, which includes lining the mold with pieces of paper arranged in overlapping relation to one another and pasting together the overlapping portions of said pieces of paper, preparing sandwiches by interposing wet plaster between layers of fabric and pressing said layers of fabric toward one another and then cutting-up this composite material, smearing said sandwiches with wet plaster, and then laying and pressing said sandwiches in overlapping relation to one another against said paper, whereby said paper and pieces of fabric are bonded together by the plaster when it dries.

LILLIAN L. GRENEKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTs

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