US2487965A

US2487965A - Manufacture of shoe lasts

Info

Publication number: US2487965A
Application number: US757383A
Authority: US
Inventors: Frank G Dresser
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-06-27
Filing date: 1947-06-27
Publication date: 1949-11-15
Anticipated expiration: 1966-11-15

Description

Nov. 15, 1949 F. e. DRESSER 2,487,965

MANUFACTURE OF SHOE LASTS 3 Sheets-Sheet 2 F'i] .d June 27, 1947 ATTORNEY Nov. 15, 1949 F. G. DRESSER 2,487,965

MANUFACTURE OF SHOE LASTS Filed June 27 1947 s Sheets-Sheet s INVENTOR ATTORN EY Patented Nov. 15, f.

UNITED STATES/PATENT "OF CE. il

" mass) MANUFACTURE OF SHOE LASTS Frank G. Dresser, Providence, R. 1.

Application June 27, 1947, Serial No. 757,383

1 Claim.

My present invention relates to the manufacture of a shoe last. More especially it has to do with an improved method and means for making a metal last which substantially duplicates the shape of a relaxed foot and is adapted for use in a last-making machine as a templet or pattern for making the desired wood last to be used in the subsequent manufacture of a shoe.

So far as I am aware shoe lasts are made to correspond to the shape of a foot when it is supporting its share of the body weight. Under this condition both the longitudinal and transverse arches are usually depressed, inasmuch as the whole foot assumes a more fiat shape than when it is not Supporting any weight. As a result, shoes made from such made lasts give no particular support to the arches and because of this, tend to allow the arches to be further depressed.

'I have found from my own experience that if a last is made like the shape of the foot when it is not carrying anyweight at all but is fully relaxed, then the shoe made on that last does aid in the support of the arches and gives a desired foot-ease while the shoe is being worn.

It is accordingly a principal object of my invention to provide a method of producing a shoe last which correspond-s substantially with the shape of a foot when in a suspended or relaxed condition. Another object is to provide apparatus which enables a foot to be easily held in such relaxed condition within a sectional mold box having insertable and removable partitions which permit the sections of the box and the molds formed therein to be easily separated. Still another object is to provide a plurality of adjustable guides adapted to keep the foot motionless and in proper position during the initial molding process. And a still further object is to provide a metal reproduction of a plaster cast having a metal core entirely covered by a thin fusible metal skin. These and other objects and .advantageous features are more fully disclosed in the accompanying drawings, specifications and appended claim.

It has been found desirable, in the manufacture of a shoe last, to provide a new way for making the templet or master shoe last, to which end I have devised a method which comprises molding a negative impression of a suspended and relaxed foot, and then using this impression as a mold to produce a plaster cast which is the exact duplicate of the relaxed foot. The cast is suitably elongated and shaped at its forward end to provide the desired shape of the toe of the shoe and then from this cast a second negative impression 55 is made. Within this second impression is suspended a metal core of less dimension than the impression so as to provide a hollow space about the core. Fusible metal is then poured between the core and the surface of the said impression to produce the templet or master shoe last of the foot in relaxed condition.

In the drawings:

Fig. 1 is a front elevation of my invention, showing the carriage, chair, leg support and mold box;

Fig. 2 is a side elevation of Fig. 1 showing a supported leg and foot in dotted outline;

Figf3 is a top perspective view of the mold box;

Fig.4 is a top plan view of the mold box filled with molding material, the foot outline being shown by dotted lines;

Fig. 5 is a vertical sectional view taken on line 5-5 of Fig. 4;

Fig. 6 is a plan view of the mold box with the sections thereof and the molding material therein in separated relation;

Fig. l is a vertical sectional view of the plaster cast with its forward portion extended and shaped as desired;

Fig. 8 is a top plan view of the mold box filled with molding material about the plaster cast shown in dotted lines;

Fig. 9 is a vertical sectional view taken onthe line 9-9 of Fig. 8 showing a metal core in the impression;

Fig. 10 is a vertical sectional view similar to Fig. 9 after the fusible metal has been poured; and

Fig. 11 is a front perspective view of the finished metal templet or master last.

Referring to the drawings, my present invention comprises a movable frame 10 mounted on grooved wheels I! which run on tracks H of an intermediate carriage l6 which in turn is mounted on grooved wheels I8 which run on tracks of a base 22. The two sets of tracks are disposed at right angles and thus the frame Hi can be adjusted to any desired position by the handwheels 24 and 26, one of which effects movement of the frame with respect to the intermediate carriage and the other causes travel of the frame and carriage with respect to the base. A chair 2B ismounted on a post which can be moved vertically by means of a handle 32, and gears 38. The chair may be aligned with a U-shaped leg support mounted on a fixed frame 38. The support 36 and its supporting rod 40 are vertically movable by suitable adjusting means 62. Two angle iron steps 44 are secured one on either side of frame 38 to permit ready access to the chair.

A sectional m'old box 4| is positioned on the frame 38 in line with the leg support 36 and comprises two separable forward sections 48, I and two separable rear sections 82, 64. (See Fig. 8.) These sections are provided with abutting flanges 48a, Illa, 52a, and 54a, whereby the several sections may be removably secured together by C clamps 5B. Mounted on the base plateof each separable section is an adjustable foot guide 58 pivotally mounted as at B0. A longitudinal partition 62, in two parts 820 and 62b, with curved cut-out portion He is clamped between the flanges at the ends of the mold box sections and a cross cooperating partition 64,111 two parts 64a and 84b, with cut-out portion 640, is similarly' clamped between the flanges at the sides of the mold box.

The subject is seated in the chair 28 with the leg resting on the support 36 and the foot 68 suspended centrally in the mold box 48. With the foot thus suspended the guide elements 58 are adjusted to abut the sides of the foot and hold it motionless without interfering with its relaxed condition. The parts 82a and 62b of the longitudinal portion 62 are placed as close as possible to the foot and the end clamps 56 tightened. Similarly the parts 64a and 8422 are set in against the sides of the foot and the side clamps 56 tightened.

A hardening compound 88 (see Fig. 5), preferably plaster-of-Paris, is poured into the mold box, all around the foot and allowed to harden. This produces a mold with an impression exactly the same shape as the relaxed foot. The two rear sections 52 and 54 are unclamped together from the front sections 48 and 50, and these half portions of the mold, together with sections 62a and 62b of the longitudinal partition 62, are withdrawn from the foot. As this occurs, the sections 64a and 641) are also freed from the foot.

The mold box portions with the plaster mold therein are again clamped together and plaster,

of Paris is poured into the cavity or impression previously formed by the foot, thus forming a plaster cast exactly the same shape as the relaxed foot. This cast is then removed and the forward portion of it formed and elongated a desired length with paraflin or other suitable material, as at 10a (see Fig. '7), to give the desired shape to the toe of the shoe.

The plaster cast H1 is now placed in the mold box which in the meantime has been cleaned. This time the cross partition 64 may be omitted and only the longitudinal partition 62 used. Fresh molding compound is poured into the box to form a second mold 12 (see Fig. 9) about the plaster cast 10. When this has set one pair of the side sections are together separated from the other pair of side sections to provide a half longitudinal mold 14. With the cast 10 removed each half mold 14 therein is placed on its side and a sheet of asbestos 16 is clamped over the top of the mold half (now in the normal position of a side) closing the half-ankle opening.

A metal half core 18 smaller by about over-all than the half cavity 14 is suspended in the cavity and held in place by a metal strap 80 secured to the flat surface of the core and clamped to the end flanges of the mold box. Thus a narrow space 82 is formed between the metal core 18 and the mold 14.

A fusible alloy 84, such as cadmium, lead and tin, is poured into the space 82, and adheres to the surface of the half core 18, thus forming a thin metal skin on the half core. (See Fi 10.) If desired, the curved surface of the half core 1a may be studded with the heads of spaced flat-headed screws, slightly projecting, to insure adhesion of the metal skin 84 to the half core 18.

The outer surface of the skin 84, which is now a part of the whole metal half core, is substantially the same size and shape as one half of the plaster cast 10, which, except for the added toe portion 10a, is exactly the shape of the relaxed foot. This uniformity of shape and size is made possible by using the thin fllm of fusible metal 84 because its shrinkage is negligible.

When a like procedure has been completed with the other half mold both halves are bolted together as at 86 (see Fig. 11) to form a metal last 88 which duplicates the subject's suspended and relaxed foot except for the elongation of the toe portion. The finished metal last is placed on a last lathe and used as a guide to make a duplicate wooden last.

I have devised an improved method for the manufacture of a shoe last wherein a metal last is made to duplicate a foot in a relaxed and suspended condition. By covering an approximate sized metal core with a thin fusible metal skin, the problem of shrinkage of the metal on cooling is overcome and the flnal shape of the metal last is substantially that of the relaxed foot.

So far as I am aware, it is a novel procedure to make a last corresponding to the shape of a foot when the latter is in its relaxed condition. Then the bones of the foot are not carrying the weight of the body and so both the longitudinal and transverse arches are at their highest point and not spread out; By making a last corresponding to this relaxed shape of the foot then when the foot is placedin a shoe made on such a last, the shape of the insole and the upper along the sides of the shoe will resist the usual deformation of the arches that normally occur when the body weight is imposed on the feet.

I claim:

A method of making a metal pattern for a wooden shoe last which comprises supporting a foot by the leg alone and in a relaxed condition in an assembled mold box having four removable sections with vertically disposed parting partitions arranged at right angles to one another and extending from the adjacent vertical edges of the said sections to close by the surface of the foot below the ankle joint, pouring a charge of fluid molding compound into the mold box about the entire foot up to the ankle joint to form an exact impression of the foot in the compound when the latter has hardened, separating the removable sections and parting partitions and removing the foot, re-assembling the said sections and said partitions to provide in the hardened composition a cavity the exact shape of the said foot, pouring another charge of the fluid molding compound into the said cavity to form an exact cast of the foot when the compound hardens, separating the mold box sections and parting partitions and removing the said cast therefrom, adding semi-plastic material to the toe end of the cast and shaping it to the desired interior shape of the ultimate shoe to be made, cleaning the mold box and re-assembling the sections thereof about the said shaped cast supported in the box with a parting partition vertically disposed along the middle of the mold box from the toe to the heel end thereof, pouring a third charge of the fluid molding compound into the mold box about the said shaped cast to form a cavity corresponding thereto, separating the ace-1,005

ing said partitions and the shaped cast there-' from placing the two halves of the mold box on their sides with the half cavity in each open- 5 ing upward, placing a temporary flat cover along each half cavity at the ankle joint, supporting a metal half core in each half cavity so as to leave a narrow space between the metal core and the adjacent surface of the cavity, filling the said narrow space with metal in the fluid state capahie of hardening and bonding with the halfmetal core with no appreciable shrinking of the said metal filling from the said adjacent surface or the cavity, thus forming a halt metal pattern corresponding with the exact shape oi. half of the foot plus the shaped toe end, followed by joining the said half patterns together to providethecompietedmetflpattemiorusecn-a last-making machine. 7

FRANK G. DRESER.

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

UNITED STATE PATENTS Number Name Date i 45,178 Riliot Nov. 22, 1864 384,448 Keller June 12,1888} 1,259,224 Guibert Mar. 12', 1918 1,504,822 Hess Aug. 12, 1924 1,556,802 Page Oct. 13,1925 1,715,507 Kyle June 4, 1928 1,934,239 sch Nov. '2, 1933 .1 1,981,941 Baxter Nov. 27,1934 2,120,987 Murray June 21, 1938