US3536805A - Method of making shoes with shapeholding supporting frame - Google Patents

Description

0:1.27, 1970 B. ROMEN v ,5 6,80

" METHOD OF MAKING SHOES WITH SHAPE-HOLDING SUPPORTING FRAME Original Filed June 27, 1967 i 2 Shets-Sheet 1 INVENTOR .EBvu no R om an YM/Zmm &

Rhizome/5s B. ROMEN 3,536,805

METHOD OF MAKING SHOES WITH SHAPE-HOLDING SUPPORTING FRAME Oct. 27, 1970 Original Filed June 27, 1967 2 Sheets+Sheet 2 INVENTOR Bruno Rom? BY &

Hzovuess United States Patent Office Patented Oct. 27, 1970 3,536,805 METHOD OF MAKING SHOES WITH SHAPE- HOLDING SUPPORTING FRAME Bruno Romen, 12 Guaitastrasse, Kronberg, Taunus, Germany Original application June 27, 1967, Ser. No. 649,265, now Patent No. 3,393,460, filed July 23, 1968. Divided and this application May 7, 1968, Ser. No. 749,894 Claims priority, application Germany, Apr. 19, 1967,

Int. Cl. A43b /00; A43d 65/00; B29b 7/08 US. Cl. 264-244 4 Claims ABSTRACT OF THE DISCLOSURE A method of producing a shoe includes the steps of placing a full length sole having a heel region and a flexible front part into a mold having an appropriate shape for forming a heel cap extending substantially to the arch portion of the shoe, holding a portion of an upper surface of the sole in the heel region against an upper part of said mold and spaced from a lower part and side parts of the mold and injecting plastic into the mold while the sole is so held so as to mold a heel cap having lower parts extending around the lateral sides of said heel region and overlapping the lower side thereof and molded thereto.

BACKGROUND OF THE INVENTION This application is a division of application Ser. No. 649,265, filed June 27, 1967, now Pat. No. 3,393,460 dated July 23, 1968.

The present invention relates to a method of constructing shoes which provides the shoe with a built-in shapeholding frame which consists of a molded part of plastic which is produced by injection molding and comprises a rigid insole part which extends between the heel and ball areas of the shoe, and a heel cap which is integrally connected to this insole part and extends forwardly approximately to the arch portion of the shoe. The outer side of the supporting frame is then covered by the material of the upper of the shoe.

The supporting frame of a shoe of this type which may be produced in a simple manner, for example, by injection molding or casting, not only forms the shape-holding body of the shoe but also serves as a shape-holding support for the leather of the upper. The shaping of the rear part of the upper which in previous shoe constructions had to be carried out on a heel forming machine may therefore now be omitted. This not only renders the manufacture of a shoe considerably more simple and less expensive, but it also permits such a shoe to be made of a thinner leather of a lower quality without requiring the use of an intermediate lining. Since the supporting frame may be made as a molded part of plastic, a shoe which is provided with such a frame will have and retain the shape of the last on which it is made much more accurately than a shoe the shape of which depends primarily upon the stability of the material of the upper, for example leather.

In pursuing the invention, it was found that difliculties may occur in making the supporting frame of a shape in accordance with the last if the insole part of this frame has a considerably greater thickness than the heel cap. Due to the difference in the length of time in which the different parts of the supporting frame solidify, the danger occurs that the frame may be distorted by unequal shrinking of these parts.

SUMMARY OF THE INVENTION According to the invention, these difficulties may be substantially overcome by molding the supporting frame in such a manner upon a sole which extends along the entire length of the shoe and will practically not shrink as the result of the molding operation that the supporting frame overlaps the lower side of the sole, While the part of this sole which projects forwardly from the supporting frame forms a flexible lasting sole. Aside from reducing the shrinkage, this full-length sole therefore has the further object to provide the shoe bottom with a flexible front part which is important for permitting a proper rolling motion of the foot. The supporting frame together with the full-length sole therefore forms a single prefabricated component.

BRIEF DESCRIPTION OF THE DRAWING to FIG. 2;

FIG. 6 shows a bottom view of the built-in part according to FIG. 2; while FIG. 7 shows a cross section which is taken along the line VIIVII of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated in the drawings, the shoe structure according to the invention comprises a full-length sole 1 which consists of a flexible but shape-holding material, for example, a fibrous synthetic-resin molded compound, which may be easily glued together with the inner lining of the upper, not shown. The sole 1 is provided within the heel area with an aperture 2 by stamping out a tongue 3 which is still connected at its front end to the sole 1. This sole is placed into the mold in the position as illustrated in FIG. 1 so that the tongue 3 is bent downwardly and the aperture 2 is open so that it can be filled with the plastic which forms the supporting frame.

The upper side of tongue 3, that is, the side facing the foot, is reinforced by a strip 4 of spring steel which is secured thereto and braces the arch of the foot. When the supporting frame consisting of the heel cap 5 and the insole part 6 is being molded together with the sole 1, the plastic material forming this frame will flow over the steel strip 4 and thereby cover the same completely in the manner as illustrated in FIGS. 3 and 7.

By bending the tongue 3 downwardly, it may be pressed so firmly against the wall of the mold during the molding of the supporting frame that the lower side of this tongue will not be covered by plastic. The lower side of sole 1 is therefore covered with the plastic of the supporting frame only within the area of the marginal strip 1' which surrounds the aperture 2.

For keeping the upper side of this marginal strip 1' of sole 1 free of plastic, this part of the sole is pressed firmly against the wall of the mold while the supporting frame is being molded. The pins which are provided in the mold to hold the tongue 3 and the marginal strip 1 in the desired position during the molding operation leave small apertures 7 in the molded product as indicated in FIGS. 5 and 6.

If the full-length sole 1 consists of a material which may be easily glued together with the inner lining of the shoe, the upper side of the marginal strip 1 which is not covered with plastic will form a very suitable gluing surface for securing the supporting frame to the inner lining of the shoe.

By the feature of the invention of providing the rear part of sole 1 with the aperture 2, the result is attained that the plastic of the supporting frame may also flow over the arch portion of sole 1. The coating 8 of plastic which is thus formed ends near the center of sole 1 at a short distance from the line which forms the axis about which the sole is bent during the natural rolling motion of the foot. This prevents the sole 1 from breaking within this area. The coating of plastic within the arch portion on the upper side of sole 1 has the advantage that, due to the shrinking of the plastic while cooling, a dished recess is formed which is very suitable for adapting the sole to the shape of the foot. If the coating of plastic would not be provided on the upper side but on the lower side on sole 1, this would result in a bulging of the sole in the upward direction in deviation from the shape of the foot.

As illustrated in FIGS. 2 and 5, the front end of the plastic coating 8 forms a concave are 9. The marginal parts of the plastic coating 8 therefore extend farther toward the flexible part of sole 1 and thereby improve the stability of the foot by considerably increasing the resist ance of the sole against bending in the lateral directions.

As shown particularly in FIG. 4, the ball area of the sole 1 in front of the are 9 is likewise molded so as to have a dished shape in accordance with the shape of this part of the bottom of the foot and the corresponding last. This dished shape is preferably molded in the same operation with the molding of the supporting frame upon the sole 1 by employing the heat and pressure of molding the latter parts also for molding the sole 1 to the desired shape.

The operation of molding the supporting frame also serves for providing the lower side of the tongue 3 with a projection 10 to which a heel, not shown, may be subsequently secured. For producing this projection 10, tongue 3 is provided with an aperture 11 through which the plastic may flow into a recess in the wall of the mold which has a shape in accordance with the projection 10 so that the latter will be formed therein. This projection 10 is preferably made of an angular blockshape so that when the heel is fitted thereon, it will also be properly centered.

The aperture 11 in tongue 3 coincides with an aperture 12 in the steel strip 4 so as to permit the plastic to flow through both apertures into the recess in the mold.

The supporting frame according to the invention preferably consists of high-pressure polyethylene which possesses the desired physical characteristics of this frame.

The plastic for producing the supporting frame is preferably injected into the mold near the rear end of sole 1, preferably at a point in front of the apex of the sole. The molecules will thereby be oriented in the longitudinal direction of the supporting frame so that the shrinkage of the cooling plastic will have the least effect upon the desired size and shape of the molded article.

When employing the insert consisting of the full-length sole 1 and the supporting frame 5, 6, there will be a change in the conventional manner of producing the upper of the shoe insofar as the material of the upper is now drawn over the last at first at the heel area and the shoe is therefore lasted from the rear toward the front rather than vice versa as it was done previously.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim 15:

1. A method of producing a shoe comprising the following steps, in combination:

'(a) placing a full length sole having a flexible front part and a heel part which has cut into it a longitudinal tongue thus leaving a marginal strip surrounding the tongue, and which full length sole is made of a material that is substantially non-shrinking under the effects of molding plastic to the sole into a mold of an appropriate shape for forming a heel cap extending substantially to the arch portion of the shoe;

(b) holding the sole in the mold in a position wherein the lateral edge of the heel part of the sole is spaced from the inner surface of the mold and the lower surface of the tongue and the upper surface of the marginal strip are pressed firmly againt the inner surface of the mold; and

(c) injecting a plastic into the mold, in consequence of which the lower surface of the tongue and the upper surface of the marginal strip are kept free of plastic and there is obtained a heel cap having lower parts extending around the lateral edges of said heel part of the sole and Overlapping the lower side thereof and molded thereto.

2. The method of claim 1 including the step of forming, in the process of molding the heel cap to said sole, a ball portion on the upper surface of said sole by means of the action of the heat and pressure of the molding operation so as to form a dished part in accordance with the shape of a last.

3. The method of claim 1 including the step of injecting said plastic into the mold at a point near the rear end of said sole.

4. The method of claim 1 wherein, during plastic injection, said sole is held to the mold with pins.

References Cited UNITED STATES PATENTS 2,483,004 9/1949 Gregg 1221 X 2,607,061 8/1952 Leahy et a1 264244 X 2,764,768 10/ 1956 Ashley et al 264244 X 2,912,772 11/1959 Harrison 3668 X 3,035,291 5/1962 Bingham 264244 X 3,068,872 12/1962 Brody 3668 X 3,026,573 3/1962 Ciaio 264-244 X ROBERT F. WHITE, Primary Examiner R. H. SHEAR, Assistant Examiner

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