US2961714A - Process of manufacturing molded shoes contoured to fit the feet and product produced thereby - Google Patents

Description

n Nav. 29, 1960 A. E. MURRAY 2,961,714 PROCESS 0F MANUFACTURING MOLDED SHOES CDNTOURED To FIT THE FEET AND PRODUCT PRDDUCEDA THEREBY Filed April 5, 1957 2 Sheets-Sheet 1 INVENTOR Mdm Il wd ATTORNEYS Nov. 29, 1960 A. E. MURRAY PRocEss oF MANUFACTURING MOLDED saoes coNTouREn T0 FIT THE FEET AND PRODUCT PRODUCED THEREBY Filed April 5. 1957 2 Sheets-Sheet 2 'fllllllll INVENTOR ,glam [f/Waring @al MMD( .Zaag

ATTORNEYS v ground `sole are applied to complete the shoe.

United States Patent rO` IIROCESS OF MANUFACTURING MOLDED SHOES `CONTOURED TO FIT THE FEET AND PROD- UCT'PRODUCED THEREBY Alan E. Murray, '844 Colorado Ave., Bridgeport 5, Conn.

Filed Apr. s, 1951, ser. No. 650,924

'6 claims. (ci. lts-55.05)

l This invention relates to the manufacture of molded shoes contoured to fit the feet.

The art of molding shoes to the feet has only recently been developed during the past ten years on a commercial scale and each shoe is hand-made to fit individual characteristics of the wearers feet. The molding process is carried out by wetting fabric material with liquid rubber latex in uncured form and layers of wet fabric `are then carefully molded and built up on a last which reects the contours of the wearejrs feet. The molded fabric shoe form remains on the last until the rubber latex hasv cured suiciently to retain the contours of the last and then an outer leather coveringand a curedV rubber Thereafter the shoe is removedffrom the last and given a final finishing treatment. t

AIn order to provide a molded shoe that truly fits the wearers foot it is necessary to form a last which reproduces the shape and attitude which the foot assumes in a weight'bearing condition as in walking and the accuracy of the last inturn depends upon the process usedn in forming a negative cast of the foot. Taking a cast of the foot is a very difcult and critical operation and many suggestions have heretofore been made of how to take a negative cast but none of these has proven entirely `satisfactory because the cast is made on the naked foot-and even though the foot may be articially arranged in a weight-bearing positionjthe fleshy portions of the foot alongthe sides which are unsupported tend to sagvdown and give a deformation lwhich is lreproduced in the cast. This deformation is especially pronounced in Vadult feet. As a result, it frequently happens that the shoes are too wide and they fail to give adequate supportalongthe sides of the foot so that the shoe has to be reworkedkand at times completely remade starting with a new cast of the foot..

. In working with this problem, the applicant has now developedl a method for taking a negative cast of the foot wherein `the entire'foot is fully supported and contained within an`elastic support member which uniformly distributes the eshy portions of the foot about the bony structureand'prevents the Adeformations encountered with the prior art processes. The use of an elastic support member-for the foot is important because the elasticity of the support member permits itto yield and adjust itself to provide uniform andfeven pressure Afor distributionl of the fleshy portion of the foot around the bony structure just as if the foot were in a hydraulic bath under pressure. Such uniform containment of the foot can not be achieved with non-elastic materials which can not adjust and apply uniform pressure to the footand the uneven pressure of the non-elastic materials have in practice only resulted in an increased distortion of the foot.

In'accordancewith the present invention once the foot is contained within applicants elastic support member an aqueous slurry of plaster of Paris or other suitable molding material is applied to the exterior of the molded foot foform'a negative cast 'and any of the known casting techthemolded shoes ofthe prior art, in addition providecontainment and actively support the fleshy portions along the sides of the feet. Many shoes have already been manufactured in accordance with applicants principle of containment and up until now none of the shoes have had to be reworked because of a poor t.

The details of the method and structures formed in carrying out the present invention along with additional advantages thereof may be readily understood by reference to the accompanying drawings in which Fig. 1 is a side view of-a foot'having an elastic containment support member thereon which is partially in section to'bette'r illustrate the structure; Fig.v 2 is a view taken from the rear of the Fig. 1;. t t

Fig. 3 is a side view of a foot which illustrates another forrn of support member;

Figs.V 4 and 5 illustrate one way in which a plaster cast may be formed on the molded foot of Fig. l; and

Figs'. 6 through l() illustrate one way in which a shoe may be `molded Vto the foot of Fig. l within its elastic support member. f

Turning now to the drawings, Figs. 41 and 2 illustrate one form'of elastic support member 10 in place on a foot vwhich is about to be cast in plaster of Paris. Support member 10 may be formed by wrapping the foot with a strip of elastic material such as a strip of thin sheet rubber or elastic fabric material 12 such as jersey or other textile material of elastic weave which may includethreads of foot of rubber to 'increase ther elasticity of the cloth. The Wrap-- ping is started at the ball of the foot and care is taken to avoid covering the cavity which lies in front of the ball of thefoot under the toes for the reason that this cavity as later described must be reproduced in the last so that the last will properly reect the weight bearing attitude of the foot in action. The turns of elastic material are applied to the foot in overlapping relationship 'and itlis irnportant to have the material stretched out while it is beingV atpos'ition. The strip is held in place on top with a tab of Scotch tape or with metal clips (not shown) in known manner. After the wrapping of elastic fabric material is in place a second elastic wrapping is preferably applied over the rst and the second wrapping is preferably formed with a strip of thin sheet rubber 16. The advantage of sheet rubber is that it is waterproof and the plaster of Paris slurry which is later applied will not penetrate or stick to the rubber. The second wrapping of sheet rubber is applied right over the first wrapping and the strip of rubber is preferably stretched out and applied under tension following the method employed in forming the first wrapping. The second wrapping may be` fastened at the top in the manner described for the rst Wrapping. 1 f, .v

The drawings illustrate some of the beneficial `effects achieved when'my elastic support member is applied to an adult foot. The eshy portion of the unsupported Patented Nov. 29, 1960` 3 adult foot along each side tends to sag and flatten out against the ground as shown in the dot and dash lines in Figs. l and 2 and this occurs in an adult foot even though the metatarsal arch may be all right. In a sense a foot may be considered to be a bag of watery tissue and as best shown in the drawings the elastic support meniber 10 of the present invention redistributes sagging tissue and the elasticity of the member and equality of pressure applied over the entire surface of the foot effects such uniform distribution of tissue that the adult foot appears to have the well rounded symmetry of the foot of a healthy child. As shown in Fig. 2 my elastic support member rnay also help in bringing the ankle of the foot back into proper alignment with the bony structure of the foot and this reorientation of the bony struc-` ture assists in achieving proper redistribution of watery tissue.

After elastic support member 10 is in place on the foot a slurry of plaster of Paris or other material capable of forming a cast is applied to cover the entire foot up to line 14. The cast may be formed in known manner but I prefer to form the cast in accordance with the teaching in my copending application Serial No. 621,226 tiled November 9, 1956 and entitled Method of Taking Cast of Feet in Dynamic Position and Product Thereof. As set forth in my copending application the foot is arranged in weight-bearing condition with the heel raised so that the weight bears against the ball of the foot and toes. The effect of this is to slightly elongate the toes and tense the muscles in the foot so that the foot is in the dynamic weight-bearing condition which it assumes in walking. A plaster of Paris slurry is then applied over the top of the foot and down in under the raised portion so that the entire foot is covered with the plaster of Paris slurry except that portion at the front which is resting on the support. Fig. 4 shows this top portion of the plaster of Paris cast 18 in position on the foot of Fig. 1 which as previously described is contained within its elastic support member 10.

As shown in Fig. 4 a plurality of rods 20 positioned between the toes are arranged to provide vent holes in cast 18. After the plaster of Paris has set enough to hold its form but while it is still soft, a dividing line is cut into the front and back of the cast by means of a dull knife blade 22. The plaster is then allowed to set and after it is set the foot with the cast on it is removed from support 24 and some grease or other separating material is rubbed on the bottom of cast 18. Thereafter as described in my copending application and shown in Fig. 5 of the drawings of the instant application rods 20 are removed from the cast and the foot with cast 18 thereon is pressed down into a pan 32 containing a second plaster of Paris slurry 34 to obtain a negative cast of the bottom exposed front portion of the foot. Removal of rods 20 allows trapped air to escape from cast 18 and as a result the plaster of Paris is free to flow up into the cavity under the toes to form a pyramid in the base of the cast which will of course be reproduced in molded shoes built up on the last which is subsequently formed.

After the plaster of Paris 34 of the bottom half ofthe cast sets, the foot along with the top portion of cast 18 is removed from the bottom portion of the cast and the two halves will readily separate without sticking because of the grease previously applied to the bottom of the' cast 18. Thereafter cast 18 is sharply tapped so that it will separate into two halves along the dividing lines cut into it with knife 22. This releases the foot which is readily removed from the cast since the outer rubber wrapping 16 does not stick to the plaster ofParis. The elastic support member is now removed from the foot. The negative cast is thereafter reassembled and a shoe last is made in the negative cast in known manner and a molded shoe is built up on the last. y

While I have described my invention in connection with an elastic support member made up of a tirst wrapping of an elastic fabric material covered with a second wrapping of a strip of thin sheet rubber, it will be understood that the wrapping may be formed with elastic fabric material alone or on the other hand it may be formed entirely of sheet rubber. If elastic fabric material is used alone I prefer to coat the exterior of the fabric wrapping with grease to prevent it from sticking to the plaster of Paris cast, In the case of the strip of rubber sheeting some advantage is gained by positioning a plurality of notches (pinking not shown) along both sides of the rubber strip as this tends to prevent the strip from gathering up when it is applied to the foot. l The rubber strip 16 is most conveniently formed by cutting a thin sheet of highly elastic rubber up into strips and for best results I prefer `to use rubber sheeting used by dentists in forming a dental darn. The thickness of such sheeting is about that of a good grade of bond paper. The width of the strips of elastic material is not especially critical but best results are achieved with a strip about 11/2 to 31/2 inches wide. The thickness of the iinal wrapping is not critical but -it should not be more than about 1A; inch thick and for best results I strive for a thickness of about 1,/64 of an inch and this is about the thickness of 2 layers of jersey cloth covered with two layers of thin rubber sheeting.

Another way in which the foot may be contained in an elastic support member is shown in Fig. 3. As` there shown the elastic support member for the foot comprises a sock 26 which is made of a single sheet of rubber and as in the case of the elastic support member of Fig 1 the sock is made of such size that it will extend from a line 28 situated well above the ankle down to a line 30 which marks the area of the ball of the foot and the elastic sock is completely open in front and is short enough so that it does not cover the cavity under the toes at the front of the foot. The sock of course must be small enough so that it will be stretched out when applied to the foot to give the required tension for applying positive but equal pressure over the entire surface of the foot. Proper tension may be achieved by having a plurality of socks 26 of different sizes and different size socks may be tried on until the proper tension is achieved for redistribution of watery tissue of lthe foot as described in connection with the structure of Fig. 1. If desired, the sock may of course be made of elastic fabric material without departing from the spirit and scope of my invention. While the benefit of containment and redistribution of watery tissue of the foot is achieved with sock 26 the results achieved are not nearly as satisfactory as in the case of the structure of Fig. l.

While my invention has been described in connection with forming a last for the manufacture of molded shoes it will be obvious to those skilled in the art that a molded shoe may be built up directly on the foot in its containment wrapping. The shoe may be built up on the molded foot of Fig. l or Fig 3 in accordance with known methods and the containment wrapping of Fig. 1 or sock of Fig. 3 then becomes an inherent part of the shoe.

One preferred way of building up a molded shoe on the containment wrapping of the foot of Fig. 1 is described in detail in my copening patent application Serial No. 542,708 filed October 25, 1955 and entitled Footwear and Process of Producing Same. As there described and as illustrated in Figs. 6 through 10 herein akmolded shoe is made by first placing a fabric mat 36 preferably a terry cloth mat on a support 38. The mat preferably comprises a plurality of layers of terry cloth which have been wet with liquid rubber latex in uncured form and care is taken to prevent the mat from sticking to the support. A separating sheet made of vinyl plastic (not shown) may be used for this purpose. The foot of Fig. 1 with its elastic support member 10 thereon is pressed down -into the wet terry cloth mat to form an impression 40 of the bottom of the foot therein. The elastic support member is preferably coated with grease to prevent it from sticking to the mat and after the latex in the mat has set enough to retain the foot impression therein the foot is removed and the terry cloth mat is trimmed away along the outline of the foot yimpression to form a foot platform 41. If desired, plaster orf Paris may be lightly dusted over the latex to speed up curing.

An ordinary sock 42 of cotton or other suitable fabric is now pulled over the elastic support member on the foot and the exterior of the sock is Wet with liquid rubber latex in uncured form. The foot with sock thereon is pressed do-wn on the foot platform 41 (Fig. 8) tosecure the platform to the sock on the bottom of the foot. The foot is then lifted with the platform attached and a second sock 44 is pulled over the first sock so that the foot platform Iis firmly secured between the socks (Fig. 9). If desired, additional latex may be applied to the exterior of sock 42, and also to the exposed surface of the foot platform to establish a firm bond with sock 44. The exterior of sock 44 is then coated with uncured liquid rubber latex and co-vered with monks cloth and then an outer covering of leather 45 wet with latex may be applied to complete the side wall of the shoe. (Monks cloth not shown.) After the latex has set sufliciently to maintain the shoe in its molded form the shoe is cut from the foot as described in my copending application Serial No. 542,708 and a ground sole such as a cure rubber ground sole 46 is applied with liquid rubber latex to form the finished shoe 48 of Fig. 10.

Modifications of the way in which foot platform 41 is made will be obvious to those skilled in the art. For example the foot platform may also be made as described in my copending application Serial No. 542,273, filed October 24, 1955 entitled Foot Supporting Platform and Process of Making Same.

It Will be understood that I intend to cover all changes and modifications of the preferred form of my invention herein chosen for the purpose of illustration which do not constitute departures from the spirit and scope of my invention.

What I claim is:

1. In the manufacture of molded shoes contoured to a shoe last of the type having individual characteristics of the wearers foot therein, the method of taking a nega tive cast of the foot which comprises the steps of applying one end of a strip of elastic material to the foot, stretching out the elastic strip to put it under tension, applying overlapping turns of elastic material to the foot While maintaining tension on the Strip, applying such overlapping turns to the foot to cover the area from a line across the ball of the yfoot located adjacent to the cavity under the toes up to a line positioned above the ankle, fastening the second end of the strip to preserve tension in the elastic wrapping so formed whereby the entire surface of the wrapped portion of the foot is subjected to uniform pressure to effect redistribution of watery tissue therein and then applying a moldable material to the exposed portion of the foot and to the exposed portion of the elastic support member which moldable mater-rial is adapted to set and harden and form a negative cast of the molded foot for the manufacture of a shoe last of the type having individual characteristics of the wearers foot therein.

2. The method specified in claim 1 in which the wrapi ping is formed by applying a strip of fabric with elastic weave to the foot.

3. The method 4specified in claim 1 in which the wrapping is formed by applying a strip of thin sheet rubber to the foot.

4. The method specified in claim 2 which includes the stepof applying a strip of sheet rubber over the elastic fabric material to lform a second outer elastic wrapping thereon.

5. The method specified in claim l which includes the steps of holding the foot with elastic support thereon in weight-bearing position with the heel raised and weight supported by the toes and ball of the foot, applying the moldable material to the exposed portion of the foot and to the exposed portion of the elastic support member and then after the moldable material has set lifting the foot up and then applying a second mas-s of moldable mate:- rial to the bottom exposed portion of the toes and ball of the foot to complete the negative cast.

6r. The method as specified in claim 1 in which the negative cast of the foot is formed -by applying an aqueous slurry of plaster of Paris to the exposed portion of the foot and to the exposed portion of the elastic support member.

References Cited in the file of this patent UNITED STATES PATENTS 290,652 Sturmer Dec. 18, 1883 1,404,896 Rowley Jan. 3l, 1922 1,647,639 Larson Nov. 1, 1927 2,547,419 Sugarman et al. Apr. 3, 1951 2,593,742 Friedman Apr. 22, 1952 2,606,333 Murray Aug. l2, 1952 2,668,304 Murray Feb. 9, 1,954

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