US2138974A - Method of making inner molds for shoes - Google Patents

Method of making inner molds for shoes Download PDF

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US2138974A
US2138974A US4740A US474035A US2138974A US 2138974 A US2138974 A US 2138974A US 4740 A US4740 A US 4740A US 474035 A US474035 A US 474035A US 2138974 A US2138974 A US 2138974A
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Prior art keywords
foot
mold
last
cast
molds
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US4740A
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Clifford K Macdonald
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United Shoe Machinery Corp
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United Shoe Machinery Corp
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00Producing footwear
    • B29D35/0009Producing footwear by injection moulding; Apparatus therefor
    • B29D35/0018Moulds
    • B29D35/0036Moulds with displaceable sole plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00Producing footwear
    • B29D35/0054Producing footwear by compression moulding, vulcanising or the like; Apparatus therefor
    • B29D35/0063Moulds
    • B29D35/0081Moulds with displaceable sole plates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29DPRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D35/00Producing footwear
    • B29D35/12Producing parts thereof, e.g. soles, heels, uppers, by a moulding technique
    • B29D35/128Moulds or apparatus therefor
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S264/00Plastic and nonmetallic article shaping or treating: processes
    • Y10S264/30Use of anatomy in making a mold or using said mold
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S29/00Metal working
    • Y10S29/028Magnetic recording digest

Description

C. K. M DONALD METHOD OF MAKING INNER MOLDS FOR SHOES Dec. 6, 1938.

Filed Feb. 4, 1955 7 Sheets-Sheet l R a /N Dec. 6, 1938. c, MacDONALD METHOD OF MAKING INNER MOLDS FOR SHOES 7 Sheets-Sheet 2.

Filed Feb. 4, 1955 Dec. 6, 1938. c. K. M DONALD 2,133,974

METHOD OF MAKING INNER MOLDS -FOR SHOES Filed Feb. 4, 1935 v 7 Sheets-Sheet 3 A/VEA/ TUE;

Fi 7 g Dec. 6, 1938.' c. K.. M DONAL D 2,138,974

METHOD OF MAKING INNER MOLDS FO R SHOES Filed Feb. 4, 1935 7 Sheets-Sheet 4 Dec. 6, 1938. c. K. M DONALD METHOD OF MAKING INNER MOLDS FOR SHOES Filed Feb. 4, 1955 7 Sheets-Sheet 5 Fig? 13 y [VVENTUFF Deg. 6, 1938.

Fig 18 Dec. 6, 1938. c. K. MacDONALD 2,138,974

METHOD OF MAKING INNER MOLDS FOR SHOES Filed Feb. 4, 1935 7 Sheets-Sheet 7 Patented Dec. 5, 1&3?

WEARING HNNER P/IOLDS FGR SHQES @iiiford K. IvIacB cnald,

Bro clrtcn, Mass, assign- Application 4, 1935, Serial No. 1,740

This invention relates to the manufacture of shoes and inner molds for shoes and is illustrated herein with reference to improved methods of making such inner molds.

In order to position and support even tively normal foot properly in shoe the surface which engages the bottom of the footshould conform as accurately as possible to the shape which the bottom surface of the foot assumes when the foot is located a shoe and supporting its share of the weight of the body. in other words, to obtain the most beneficial results it is not enough that the supporting surface of the shoe conform substantially to the shape of the bottom of the foot w en the latte" is relaxed or is located in the position it assumes when not in a shoe but, on the contrary, the actual position that the bottom of the foot assumes when it is placed in a shoe should be duplicated, if possible, with the foot expanded or distorted as it is under the weight of the body. If theabove conditions are obtained, as by the use in a shoe of an inner mold or filler piece which conforms sub stantially to the shape of the bottom of the foot under such conditions, the foot will receive the best possible support. It will be obvious that the above facts, which are true with respect to relatively normal feet, are equally true when considering abnormal feet having defects or deformities which prevent them from properly supporting the weight of the body.

An important point to keep in mind, however, in constructing inner .molds, shank pieces or other devices for supporting feet in shoes is that the lower or bottom surface of the inner mold or other such device should, in order to secure the best results, conform exactly to the upper surface of the insole of the shoe. For example, if the lower surface of a supporting memb or inner mold differs in shape from the insole against which it is located, the weight of the body will gradually force the inner mold into conformity with the insole and the original shape of the upper or supporting surface of the inner mold will be lost. Moreover, differences in shape between the upper surface of the insole and the adjacent surface of the inner mold may cause the latter to slip or rub heightwise of the shoe, which will tend to wear away the lining of the shoe and the edges of the inner mold, thereby causing a looseness which will materially reduce the effectiveness of the inner mold as a support for the foot.

While various methods have been utilized in the past for constructing inner molds or filler rela- (El. l -55) pieces for supporting feet in shoes, none of them have,'so far as is known, been adapted to produce an article which will completely overcome the difficulties set forth above.

An object of the present invention is to provide 5 an improved method of making inner molds for supporting feet in shoes which is particularly adapted to produce an inner mold which will fit the foot properly when the latter is in the position it assumes in a shoe while supporting the 10 weight of the body, and which will be so constructed as to retain its shape and thus prevent any undesired slipping or rubbing relatively to the shoe.

To the attainment of this object and in accord- 15 ance with one aspect of the invention, the bottom surfaces of a persons feet, whether normal or otherwise, are reproduced in detail and the reproductions are utilized as dies for conforming or shaping plastic material to form the foot engaging surfaces of inner molds for the feet. As illustrated herein, each reproduction is identical in shape to the bottom surface of the foot when the latter is in the position it assumes in a shoe while supporting the weight of the body. Consequently, the upper surface of the inner mold will be complemental to said bottom surface and will engage all portions of the bottom of the foot when the person is standing in a normal position, thus providing the best support it is possible to obtain.

In accordance with another aspect of the invention, the illustrated method contemplates the production of a member having a surface formed thereon which conforms longitudinally to the bottom of a foot when the latter is in the position referred to, this surface, however, being curved less than the foot widthwise. This surface is used, in cooperation with the bottom surface of the reproduction mentioned in the preceding paragraph, to shape the inner mold. The member upon which the cooperating surface is formed, as illustrated herein, is conformable or moldable lengthwise under sufficient pressure but is constructed and arranged to remain in a substantially flat condition widthwise. The cooperating surface is formed by pressing the reproduction against the conformable member and thereafter rendering the member to permit the surface formed thereon to be utilized for shaping one side of the inner mold. The side of the inner mold which is shaped by the conformed surface will thus have a longitudinal contour identical with the bottom surface of the foot but will be flatter than such surface widthwise, thereby sub- 55 V stantially corresponding in shape to the upper surface of an insole of a shoe appropriate for said foot.

In another aspect the invention comprises the pressing or molding of an inner mold the thickness of which is determined by the positions of the pressing members relatively to each other. As illustrated, the reproduction is maintained throughout the process in precisely the same angular position relatively to a plane of reference such, for example, as the horizontal as that in which it was located when made so that the conformed surface which is produced with the aid of the reproduction will be located in a corresponding angular position. Since the resulting inner mold contains the characteristics of the respective surfaces on its opposite sides it has a maximum thickness determined by the differences in shape between such surfaces, plus a minimum thickness at relatively normal portions of the foot, which is determined by the condition of the foot, this minimum thickness preferably being relatively small.

In accordance with still another aspect of the invention, the present method contemplates the production of inner molds for use in shoes made on conventional or stock lasts suitable for relatively normal feet, these inner molds conforming on their upper or foot engaging surfaces to the shapes of the feet when positioned in such shoes and supporting the weight of the body, and conforming on their opposite or tread surfaces to the upper surfaces of the insoles of such shoes. As herein illustrated, an inner mold of this type is obtained by forming a cast of the lower portion only of a relatively normal foot. The foot is first fitted to a proper shoe. The shoe is then removed and the foot is located in a molding box in the position it assumes in the shoe when bearing the weight of the body, thereby forming an impression in which a cast may be made. A conventional last, preferably that upon which the shoe was constructed, is utilized for producing in a bed or plate an impression of the bottom portion of the last. In making this impression the last is maintained relatively to a plane of reference such as the horizontal in the same angular position as that in which the foot was located when the impression of the foot was made. The cast is held in its original position and is pressed against plastic material in the impression in the bed while the bed is also maintained in its original angular position, thereby producing an inner mold having the same characteristics as the inner molds referred to above and adapted to be in serted in the shoe to which the foot was previously fitted.

While the inner molds are rigid and firm enough to afford the desired support for the feet without the use of shank pieces or stiffeners, the invention also provides, in cases where it is advantageous or desirable to provide additional support at the shank portion of the foot, an improved inner mold of the type referred to having a shank stiffener of suitable material incorporated therein, thereby rendering the inner mold less flexible at its shank portion so that the longitudinal arch of the foot will be supported firmly in proper weight-bearing position.

With the above and other objects and aspects in view, the invention will now be described in connection with the accompanying drawings and thereafter pointed out in the claims.

In the drawings,

Fig. 1 is a side elevation partly in section of a molding device or magnetic box and mechanism used therewith for obtaining a mold of the entire foot, the foot being shown positioned in the device to form an impression;

Fig. 2 is a perspective view of a measuring device for determining the heightwise positions of different portions of a shoe bottom, the device being shown measuring the forepart of a shoe;

Fig. 3 is a view similar to Fig. 1 showing in section a cast of the foot being formed in the mold and illustrating also a device which locates a bushing in the cast;

Fig. 4 is a perspective view of the cast after it has hardened;

Fig. 4a is a perspective view of the cast with its upper surface cut at right angles to the bushing, the cutter being shown in operative position in the bushing;

Fig. 5 is a front elevation partly in section of a pressing device in which the cast is mounted to form an inner mold, the cast being shown positioned in the device and having plastic material added to its toe end;

Fig. 6 is an end elevation partly in section of the device shown in Fig. 5;

Fig. '7 is a View of the cast after it has been shaped to the form of a last;

Fig. 8 shows the cast of Fig. 7 being utilized to form a pair of molds, the molds being shown in section;

Fig. 9 is a view of a Woods metal model produced from the molds shown in Fig. 8;

Fig. 10 is a View of a wood last reproduced from the Woods metal model and illustrates the manner in which a hole is bored in the heel portion of the last to receive the last thimble;

Fig. 11 is a view of the completed wood last;

Fig. 12 is a view of the wood last mounted in the pressing device and being pressed against the upper surface of a flexible profile bed which is supported on the table of the pressing device;

Fig. 13 is a longitudinal section of the flexible profile bed in the pressing device, illustrating the operation of pressing an inner mold between the bed and the last bottom;

Fig. 14 is a transverse section taken on the line X[VGV of Fig. 13;

Fig. 15 is a fragmentary view on an enlarged scale of a portion of a flexible fence used in pressing the inner mold;

Fig. 16 is a view of the completed inner mold resting on a plate to dry;

Fig. 1'? shows the inner mold tacked to the bottom of the wood last illustrated in Fig. 11;

Fig. 18 is a longitudinal sectional view of the magnetic box being utilized to form a cast of the lower portion only of a foot;

Fig. 19 shows a conventional last mounted in a molding box to produce a bed or plate containing an impression of the lower portion of the last, the box being shown in section;

Fig. 20 is a transverse sectional view taken through the forepart of the last shown in Fig. 19;

Fig. 21 is a view partly in section illustrating the manner of pressing an inner mold for a relatively normal foot;

Fig. 22 is a perspective View of the completed inner mold; and

Fig. 23 is a longitudinal sectional view of an inner mold provided with a shank piece or stiffener.

In making inner molds for shoes, in accordance with one aspect of the method illustrated herein. a plaster cast is first made of a foot which may be normal or abnormal and defective with re spect to the positions of its arches so that the foot is unbalanced and the weight of the body is not distributed evenly on the three weight bearing points of the bottom surface of the foot. In making this cast the foot A (Fig. l) is located as nearly as possible in the position it assumes when supporting the weight of the body in a shoe appropriate for the foot. A convenient way of making casts of this type is disclosed in United States Patent No. 2,657,039, granted October 13, 1936, on my application, Serial No. 672,861, filed May 25, W33, in which an apparatus referred to as a magnetic box is utilized for making a cast of objects such as the lower portion of a foot which is supporting the weight of the body.

As shown in the patent referred to, the magnetic box comprises an electromagnet 20 controlled by a rheostat 22, shown diagrammatically in Fig. 1, and provided with pole pieces 24 having grooves at their upper ends forming a guideway 25 in which is mounted a rectangular container 26, the sides of the container which engage the pole pieces being composed of magnetizable material such as iron or steel, and the other two sides being formed of non-magnetizable material.

Mounted inside the container is a supporting member 28 comprising three relatively adjustable sections pivoted to the sides of the container and carrying on their upper surfaces a mass of loose magnetizable particles or balls 30 which are adapted to conform readily to the shape of an object pressed against them. As described in the patent mentioned, the supporting member 28 may be adjusted before an impression is made in the particles by means of a hand wheel 32 and mechanism 83 associated therewith to position the difierent sections of the support 28 in accordance with the longitudinal contour of the bottom surface of the foot to be operated upon or, if desired, in accordance with the heel height and toe spring of a last or a shoe appropriate for such foot. The foot is held in a position which is as near to the correct position as it is possible to attain and is then pressed into the magnetizable particles with about half the weight of the body to form an impression of the lower portion of the foot after which an electric current is passed through the magnet. The magnetic flux passes into the magnetizable side walls of the container 26 and sets up a magnetic field in the space occupied by the particles 33 to magnetize the latter and thus render them immobile so that the impression will be retained. The device is preferably mounted on a base 3| provided with a supporting table 3 which surrounds the device and is adjustable heightwise relatively thereto,

In order tolocate the foot A exactly in the po sition it assumes in a finished shoe, it is advantageous when making the impression in the magnetizable particles to take measurements directly from a shoe which has been worn by the individual or from one which is considered proper for his foot. The measurements are taken at the forepart or ball portion of the insole of the shoe and at the heel-seat portion and are transferred to the impression in the magnetic box to permit adjustments to be made to bring corresponding portions of the impression into the same horizontal plane relatively to the table 34.

The transferring of these measurements may be accomplished with the aid of a device illustrated in Fig. 2 and comprising a base 35 having a standard or post 38 mounted perpendicularly therein. At its upper end the standard is enlarged and supports a shaft 4% which is located at right angles to the standard and is rotatable therein, a screw Mi being provided for locking the shaft 4!! against rotation should it be desired to set the device to retain a particular measurement. I At its outer end the shaft 4!] carries a relatively long rod 56 which is adjustable lengthwise and is retained in position by a set screw 48. The lower end of the rod 46 forms an indicator for engaging the upper surface of an insole of a shoe and measuring the heightwise positions of its forepart and heel portions, as shown in Fig. 2. A small depending rod 50 is fastened by a collar 5! to the rotatable shaft 48 adjacent to the standard 38 and is provided at its lower end with a pointer which passes over a stationary scale marked on an arcuate plate 52 secured by screws 54 to one end of the base 36 so that the heightwise positions of the forepart and heel portions of the shoe will be indicated on the scale.

The procedure followed in bringing the bottom surface of the impression into the same horizontal plane as the upper surface of the insole is as follows: When the measurement of the forepart of the insole of the proper shoe B has been taken, as shown in Fig. 2, the end of the ind1cator rod 46 is placed against the bottom of the forepart of the impression in the magnetic box and the table 3 3 is raised or lowered until the pointer 50 indicates on the scale 52 that the impression is located in exactly the same horizontal plane relatively to the table 34. A measurement is then taken of the upper surface of the heel-seat portion of the insole and the indicator is placed over a corresponding portion of the impression. If this portion is not located in the same horizontal plane relatively to the table the rear section of the support 28 is adjusted by the hand-wheel 32 until the scale shows that the heel portion of the impression is positioned in such plane. The individual then places his foot again in the impression and the current of the magnet is turned off to permit the particles or balls 3!! to be readjusted or positioned again in conformity with the foot, the latter now being positioned as it will be in a shoe. After the impression has been perfected the current is turned on and the foot is removed from the box.

The impression is next lined with a thin sheet of limp flexible material such, for example, as rubber or silk cloth dipped in wax, this lining material being indicated in Fig. 1 by the reference numeral 56. The foot is coated up to the ankle with Vaseline or any suitable grease and is placed in the impression to conform the lining 55 to all portions of the impression. The lining material which extends out of the impression is spread smoothly over the top surface of the particles adjacent to the impression.

A molding box or hood is now placed around the foot A in order to obtain a mold of all portions of the foot which extend above the impression, the bottom of the molding box resting on the flexible sheet of lining material 56. As shown in Fig. 1 the molding box or hood is made in two main parts, a front section 58 which is substantially triangular in shape, as seen in side elevation, and is arranged to enclose the upper portion of the forepart of the foot back substantially to the ankle bone, and a rear section 60 for surrounding the heel portion of the foot rearwardly of the ankle bone, each ofthese sections being made in two separate pieces. The sections 58 and B0 meet approximately at opposite sides of the ankle bone to form the complete cover or hood. The heel section 66 of the hood is provided at one side with an outwardly projecting flange 6| formed thereon adjacent to the section 58. Passing horizontally through this flange are a pair of screws 62 which project beyond the flange and are surrounded by compression springs 64 which bear at one end against the heads of the screws and at the other end against the flange 6|. The screws 62 are threaded into a vertical plate 63 which is substantially equal in dimensions to the flange 6|, this construction permitting the flange and the plate 63 to be spread apart to receive between them another plate 66 which may be slid inwardly to within one-quarter of an inch of the foot, thus forming a break or parting line upon which the plaster mold may be separated after it has hardened. The construction at the opposite side of the section 60 is substantially the same as has just been described, the outer portions of the slide plates 66 being bent at right angle to provide convenient means for adjusting them toward or away from the foot. The two parts of the heel section 68 are yieldingly secured together at the rear end of the section in the manner similar to that described above by horizontal screws 68 passing through rearwardly projecting flanges 69, a third slide plate 10 being inserted between the flanges and extending toward the heel of the foot to form a dividing line at the back end of the mold.

The hood section 58, covering the forepart of the foot, is likewise formed in two parts, one of them having an upstanding flange 12 extending lengthwise of its central portion which is yieldingly secured through similar screw and spring arrangements 13 to a narrow plate 74 clamped to the opposite member of the section 58 by wing nuts 15 bearing against small angle plates 18 formed on the upper side of said opposite member, the wing nuts 15 being forced against the angle plates by compression springs (not shown) surrounding the screws 16 and bearing against their heads. The flange 12 and plate 74 can be separated to receive between them a plurality of slide plates (shown herein as three), the inner edges of which are shaped or conform substantially to the longitudinal contour of the instep and toe portions of a fairly normal foot. The plates are slid toward the foot after it has been positioned in the impression until they are located about one-half to one-quarter of an inch away from the foot and thus serve to form a dividing line upon which the plaster mold which is to be formed over the forepart of the foot may be readily broken and separated. It will be seen that the above construction permits the various slide plates to be adjusted inwardly toward the foot any desired amount and the springs between the heads of the screws and the plates or flanges on the different sections will exert sufl'lcient pressure to hold the plates in their adjusted positions. Moreover, the plates 80 over the forepart of the foot can be changed readily when operating on feet which vary in shape.

The forward section 58 of the hood is also provided at each side, adjacent to the section 60, with a movable segment 82 which is pivoted at the lower portion of the section on a pin 84 and is arranged to be rotated into engagement with the adjacent edge of the section 68 to close the opening formed between that section and the section 58 when the latter is positioned at such an angle as to leave an opening between the two sections, for example, when the heel height of the foot, as determined by the shoe, is great enough to cause the forward section 58 to slant downwardly at a considerable angle. The size of this segmental opening will of course vary with the shapes of different feet and with the heights of the heels desired on the finished shoes. cordingly, the segment 82 is made large enough to cover any opening that may possibly occur.

Plaster of Paris is now poured around the foot through the opening at the top of the hood sections. The foot is covered with plastic material well above the ankle bone so that the molds will contain an impression of the entire upper portion of the foot. After the plaster of Paris has set the slide plates of the hood section 58 are slid away from the foot and that section is removed. In order to insure that the forepart mold will be repositioned in the box in exactly the same position after the foot is removed therefrom, the usual practice is to break the mold on the parting line at the ankle bone and on the line that extends over the instep portion of the foot to form two mold sections 84 (Fig. 3). These two sections are then removed to permit removal of the foot after which the two pieces may be placed back again in their original positions against the heel mold 86 which has remained in position in the box inside the heel section 60 of the hood.

The plaster of Paris molds are shown in section in Fig. 3 in a proper position for forming a cast of the entire foot. The forepart mold 84 registers perfectly with the impression. in the magnetized balls and meets the heel mold 86 on the line 88 upon which it was separated therefrom. The reason for forming a parting line at the rear end of the heel mold 86 is to permit this mold to be easily removed from the heel portion of the cast of the foot after the cast has set so that this mold may be used again should it be desired to make more than one cast of the foot from the same molds. Before pouring the plaster or Paris into the mold to form the cast the inside of the mold is greased in the usual manner.

An important part of the present method of making inner molds is the maintaining of the cast of the foot precisely in the same position throughout all steps of the process. In other Words, the position in which the foot was originally placed when making the impression, which corresponds to the position which it will assume in a shoe when supporting the weight of the body, should be retained throughout the entire procedure in order to obtain the most satisfactory results. In order, therefore, to insure that the cast can be subsequently positioned in exactly the same position as when it was made, a bushing is molded into the heel portion of the cast, this bushing being located absolutely vertical to a predetermined plane of reference herein disclosed as the horizontal and thus bearing a definite angular relation to the bottom surface of the cast. The bushing Bil may be positioned in the mold by a device similar to that shown in Fig. 3, this device comprising a base plate 92 arranged to rest on the table 34 and having an upwardly extending hollow post 94 in which is telescopically mounted a shaft 96 which is ad justable relatively to the post and is held in adjusted position by a set screw 98 threaded into a boss on the post. The upper portion of the shaft 95 carries a rotatable rod I66 positioned at right angles to the shaft and adjustable lengthwise relatively thereto, a set screw I62 being provided for securing the rod in adjusted position.

At one end the rod I00 is provided with ears I04 between which is pivotally mounted on a pin I06 another rod I08- the upper portion of which is flattened ofi at opposite sides to engage the ears I04. -The lower portion of the rod I08 is cylindrical in shape and is arranged tohold the bushing 90 which can be slid on the rod with sufficient friction to hold it temporarily thereon. At its upper end the rod I08 carries a spirit level III) of any suitable type for determining the exact angular position of the rod relatively to the horizontal plane of reference. The adjustments provided by the rotatable mounting of the rod I00 and the pivotal arrangement of the rod I8 permit a universal adjustment to be obtained by which the bushing 90 can be located in the mold absolutely vertical with the aid of the spirit level IIO. As. shown in Fig. 3, the bushing 9i? is of sufficient length to extend a substantial distance into the mold which is to be filled with plastic material to form the cast, the lower portion of the bushing being split and flared outwardly to cause it to become embedded in the plastic material and. thereby prevent it from subsequently turning or dropping. out.

When the. bushing 90 is located in the proper position in the opening in the molds, plaster of Paris H2 is poured in to fill the mold substantially to the top. The plaster of Paris is allowed to set suflici'ently to permit the cast to be removed from the molds after which the separate sections of the upper molds are carefully removed and the cast is lifted out of the impression in the magnetic box. Fig. 4 shows the cast I20 as it appears at this stage of the process with the bushing 90 permanently embedded in its heel portion and positioned so that it bears a definite angular relation to the bottom surface I24 of the cast.

The plastic material at the top of the cast is leveled off before the cast has completely set to form a smooth flat surface thereon which is perpendicular to the bushing 91* and therefore exactly horizontal when the cast is located so that the bushing is vertical. One convenient way of forming this flat surface on the cast so that it will be perpendicular to the bushing 90 is illustrated in Fig. 4a. A cutter H4 is rotatably mounted on the cast by means of a pilot I I6 which enters the bushing 90, the pilot being located at right angles to a transverse blade II! which is secured in a slot in the shank portion of the cutter by a binding screw H8. The upper end of the shank of the cutter carries a handle I2I by which the blade may be rotated to cut the plastic material while it is still in a semi-plastic condition, thus forming on the upper side of the cast a smooth flat surface I22 which is perpendicular to the bushing 90. The surface I22 on the cast may of course be formed in other ways, for example, the plastic material at the top of the opening in the molds may be leveled off at right angles to the bushing While the material is still in a plastic condition with a trowel or. other suitable. instrument. The method illustrated herein, however, is believed to be preferable because of its simplicity and accuracy.

The cast I20 is next shaped to the form of a last by adding plastic material to its toe end, reducing the height of its heel portion, and smoothing 01f the irregularities at the ankle bone, instep and heel portions without, however, altering the shape of the bottom surface of the cast. In order to add material to the toe portion ofv the cast without altering the; shape of. its bottom surface or varying the angular relation of that surface to the horizontal, the cast is mounted in a pressing device illustrated in Figs. 5 and 6, and constructed and arranged to hold the cast rigidly in the position in which it was made. The pressing device comprises a rectangular base I20 supported by legs I28 and having bolted to its upper side a supporting plate I30. Adjacent to the four corners of the supporting plate are upstanding posts or standards I32 the lower ends of which pass through holes in the plate and are threaded to receive nuts I34 which bear against the under surface of the plate and clamp the posts rigidly in upstanding. positions.

At their upper ends the posts I32 support another plate I36 which is secured thereto by nuts I38 and has a pair of ribs I30 projecting upward- 1y adjacent to its opposite lateral edges to increase its strength. Secured to the under side of the plate I36 by screws are two L-shaped members I42 which extend widthwise of the plate at right angles to its longitudinal median line and form a. guideway for a slide member I44. The slide I44, as shown in Fig. 5, is positioned transversely of the plate in the guideway M2 by a springpressed pin I46 mounted in a collar or bushing I48 threaded into an opening in the slide, the pin being urged upwardly by a compression spring I50 housed in the bushing so that the pin will be caused to snap into a hole in the plate I35 when the slide is moved widthwise until the pin registers with the hole.

The slide I44 has a boss I52 projecting downwardly near its right-hand end, as viewed in Fig. 5, this boss being located on the longitudinal median line of the plate and having a vertical opening into which is threaded a hollow stud or spindle I54 the lower portion of which projects downwardly for a considerable distance at right angles to the plate I38 and is split radially to permit it to be spread or enlarged, thus increasing its diameter. The inside of the spindle I54 is also threaded and a tapered draw bolt I56 is mounted therein, the inner end of the bolt being provided with a transverse pin which is arranged to be engaged by ears formed on the shank portion of a hand-wheel I58 which may be inserted in the opening in the boss I52 through a transverse slot I60 in the plate I35 and then rotated to thread the draw bolt farther into the spindle and thus cause the thick end of the bolt to spread the lower portion of the spindle. Before the spindle is enlarged by the draw bolt it fits inside the bushing 90 in the cast IZE. The cast is positioned in the machine, therefore, by pressing the bushing 90 over the spindle I54 and spreading the latter with the draw bolt I56 until the cast is locked rigidly in position.

Near the opposite end of the slide M4, as viewed in Fig. 5, is a pair of L-shaped strips I62 Which are secured by screws to the bottom surface of the slide and extend lengthwise of the central portion thereof to provide a guideway in which is slidably mounted a small T-shaped slide I64 having a cylindrical projection I66 extending downwardly therefrom. The projection I86 is bored vertically and threaded to receive the shank portion Iii? of a last engaging abutment or toe rest I63 (Figs. 5 and 6) which is adjustable heightwise by means of the threads and is adjustable longitudinally of the pressing machine with the slide upon which it is mounted. The slide I64 is secured in adjusted position in the guideways I62 by a pair of binding screws I'IIl threaded into opposite ends thereof. The last engaging abutment 563 is connected to the shank 16'! by a ball and socket joint, as shown in Fig. 6, so that the abutment can accommodate itse'" readily to the shape of the toe portion of a last. The abutment is also curved transversely to conform more closely to the transverse convexity of the last and is preferably covered with a layer of felt and/ or leather to prevent it from scarring the last. The last engaging abutment is not used when material is being added to the forepart of the cast 255 but is utilized later in the process, as will appear hereinafter.

Slidably mounted on each of the four uprights or standards E32 is an elongated sleeve i'i2 the lower end of which is enlarged and provided with a shoulder for supporting a rectangular plate or table H t, the table having a hole formed at each of its four corners to fit the smaller portions of the sleeves I72. Set screws il'ii threaded into the opposite ends of the table secure it rigidly to the sleeves. A pair of longitudinal reinforcing ribs H76 project downwardly from the under side of the table to strengthen it and prevent bending or warping under substantial pressure.

The table H4 is raised and lowered on the standards i32 by means of a hydraulic jack, indicated in Figs. 5 and 6 by the numeral this jack being of any suitable or conventional type and having a handle E88 by which it is operated. The jack actuates a relatively large shaft 58?: which extends upwardly and at its upper end engages the under side of the table li t, thus supporting the table and the sleeves H2 which slide on the standards i32. vided with suitable mechanism (not shown) for reversing the direction of movement of the actu ated shaft 582.

The sleeve M2 on the forward post 132 at the left-hand side of the machine, as viewed in Fig. 5, carries a collar 58! which is adjustably secured thereto by a thumb screw lBS and has a lateral projection 183 which is bored vertically and carries a bushing I96 in which is mounted a contact pin i92. The lower portion of the pin 682 is connected by a wire E94 to an electric bell E98 located under the base'of the machine, the bell being connected to batteries 1183 which, in turn, are wired to the base at 255, thus completing the circuit. The left-hand post I32 has secured to its upper end by the nut lSS a stationary arm 262 which has a downwardly extending boss in which is adjustably secured by a thumb screw 2% a measuring rod 2M having a scale formed on its forward side, the scale being graduated into eighths of an inch. The mechanism just described does not enter into the present part of the process and accordingly a full explanation of its mode of operation will be given her inafter.

The cast i520 is mounted on th spindle and the hand-wheel W8 is inserted and rotated to spread the spindle and thus lock the cast rigidly in position, as shown in Figs. 5 and 6. A half insole pattern 256 approp late for the foot from which the cast was made is next cut from heavy paper or cardboard and placed on the table ii i so that it lies in the proper position under the forepart of the cast, thus determining the length and shape of the forepart of the last which is to be made. The table is raised by the jacl: 5333 until the pattern 2w contacts with the ball portion of the cast and the toe end of the pattern is elevated slightly to bring it into engagement with the cast by inserting thin wedges 2 S2 of felt or leather between the pattern and the table. A fence of Plasteline or modeling clay El i is The jack is pro' now formed around the paper pattern, as shown in Figs. 5 and 6, and plaster of Paris 216 is poured into the enclosure until it just covers the tops of the toes. The plaster of Paris is allowed to set and the table lid is lowered to permit the removal of the cast from the pressing machine.

The plastic materia 2H3 which has been added to the toe portion of the cast is now smoothed up and shaped to the form of a last, the paper pattern Bill, which has adhered to the bottom surface the cast, being used as a guide for det' th hape and length of the toe end of ca t. In the material to the cast the pattern Zie hould be positioned on the table FM so that it or approximately one inch beyond the out" o :e toes, thereby adding substantially ti shoe sizes to the length of the cast before it is shaped to the form of a last. As stated above, the cast is also smoothed. up at other portions to eliminate irregularities such as those at the ankle bones and the instep portion but the original shape of the bottom surface of the cast i retained. The rear portion of the cast is reduced in height to approximately three inches is causing it to conform more closely to the drape of a conventional last. In reducing the of the cast, the flat surface 522 at the top of the cast may be placed against a fiat surface or late which will act as a gage relatively to which a cutter such, for example, as a circular saw, may be passed through the rear portion of the cast approximately three inches from the bottom surface of its heel and and parallel to the surface of the plate against which the cast is positioned. In this way a new surface 258 is formed on reduced cast (shown in Fig. 7) wll ch is located at right angles to the bushing 93 and bears the same angular relation to the bottom surface of the last-shaped cast as the flat surface of the original cast bore to said surface.

The last-shaped cast is now utilized in the forming of a pair of plaster molds from which is produced a last model suitable for use in a last lathe to reproduce a wood last. The last 22s is *st coated t 1 shellac in order to cause Plasteline or modeling clay to adhere more readily its outer surface. A parting line (Fig. 8) is formed around the widest portion of the cast by placing one arm of a carpenters square or other suitable instrument against the side of the cast while the latter is located in an upright position on a fiat surface and then moving the square around the priphery of the cast while keeping the other arm of the square in contact with the flat surface, thus scratching a mark around the widest portion of the cast to establish the proper parting line for upper and lower molds. A fence is formed around the cast with the modeling clay, the lower side of the fence coinciding with the parting line The portion of the cast below the fence is then greased to prevent plastic materialfrom adhering thereto and the cast is supported in a molding box or flash 2% while plaster of Paris is poured in to form a lower mold 226. After the mold 223 has set, the modeling clay is scraped off the last, its upper portion and the upper parts of the side walls of the mold are greased, and plaster of Paris is poured over the cast while it is resting in the lower mold 226 to produce an upper mold When the upper mold 228 has hardened the model 226 is removed and the molds are utilized to produce a Woods metal duplicate 239 ap propriate for use as a model in a last lathe. The

material known as Woods metal is commonly used for such purposes and comprises a composition containing four parts tin, eight parts lead, fifteen parts bismuth and three parts cadmium. It has a melting point of about 158 F. In forming the Woods metal model 230, which is illustrated in Fig. 9, the molds 226, 228 are placed in a revolving frame or box and rotated rapidly while the material is setting, thus causing the model to have a hollow interior 232 which greatly reduces its weight. The model 236 is now utilized as a model in turning a wood last in the usual manner in a last turning lathe, the wood last 234 being illustrated in Fig. 10. The wood last 234 is provided with a hingle 236 and, with the exception of its peculiar shape and the omission of a last thimble at its heel portion, generally resembles conventional lasts in common use.

In order that the girth measurements of the wood last will be somewhat less than measurements taken from corresponding portions of the foot, it is customary in turning the last from the Woods metal model to reduce or shrink the girth measurements of the wood last in the last lathe or in some other suitable manner from oneeighth to one-quarter of an inch, the length of the last, however, being kept the same as that of the last model. In order to locate a thimble in the wood last in the proper position relatively to its bottom surface E24, which, it will be noted, has been maintained substantially unaltered throughout the preceding steps, the fiat surface 218 at the top of the last may be placed against a flat gage plate or collar 238, as shown in Fig. 9. A drill 246 of the proper size and located perpendicularly to the surface of the gage plate 238 may be utilized for boring a hole in the heel section of the last into which a thimble 244 may then be secured. To insure that the wood last 234 will be held securely against the plate 238 during the boring operation a clamping screw 242 may be forced against the heel-seat portion of the last, as shown in Fig. 10. Fig. 11 illustrates the wood last 234 with the thimble 244 secured in proper position in the heel portion thereof, the thimble being located at right angles to the flat surface "2H8 at the top of the last, and bearing the same angular relation to its bottom surface I24 as the bushing 96 bore to the bottom surface of the original cast I26.

The wood last 234 is now ready for use in forming the inner mold which is to be made for the foot. Accordingly, the last is located on the spindle 154 of the pressing machine described above, and the last engaging abutment I68 is adjusted longitudinally until it engages the fore part of the last, as shown in Fig. 12. A device hereinafter referred to as a flexible profile bed, is mounted on the table I14 of the machine and the hydraulic jack or pump H6 is operated to elevate the table and move the bed into engagement with the bottom surface I24 of the wood last.

Before proceeding further with the description of the process, a description of the flexible profile bed will be given. This bed is best illustrated in Figs. 12, 13 and 14, and comprises a rectangular frame 2 ,6 of substantial height which is open at the top, bottom and right-hand end, as viewed in Fig. 12. Mounted inside the three-sided frame 246 is a base or bed plate 248 of plaster of Paris or similar material, the upper surface of which conforms lengthwise to the longitudinal contour of a regular last of the same size as. the last 234 and having an 8/8 heel. A number of these bed plates may be constructed having surfaces which conform to the contours of lasts of different shapes and that bed which is closest in shape to the last being operated should be used. Mounted on the bed plate 248 is a relatively thick layer of yieldable material 250 such, for example, as sponge rubber and resting on the sponge rubber is a plurality of thin profile plates or gage members 252 which are substantially rectangular in cross-section, as shown in Figs. 13 and 14, and have upper edges which are fiat widthwise. The profile plates 252 are preferably about one-eighth of an inch thick and are provided with three vertical slots 254, 256 and 256. The left-hand end of the three-sided frame 236, as viewed in Figs. 12 and 13, is provided with a pair of deep grooves (not shown) which line up with the outside slots 258, 268 in the plates 252. Secured in these grooves by screws 259 are relatively thick horizontal bars 286, 262 (Fig. 14) which extend lengthwise of the device and pass through the outside slots 254, 258 in the profile plates. The opposite ends of the bars are supported in similar grooves formed in the'upper portion of a rectangular clamping plate 264 mounted on the right-hand end of the frame 246 and arranged for sliding movement longitudinally thereof to clamp the plates 252 against heightwise movement. The opposite lateral portions of the clamping plate 264 are reduced in thickness, as shown in Fig. 12, and are provided with openings whereby this member is slidably mounted on a pair of short horizontal pins 266 secured by set screws in opposite sides of the frame. A pair of compression springs 268, 210, seated in openings in the forward side wall of the frame and a similar pair in the opposite side Wall bear against the reduced side portions of the clamping member 264 and hold this member normally at the outer limit of its lengthwise movement. A rod 212, secured against rotation in a boss on the left-hand end of the frame by a taper pin 2Y3, and extending longitudinally of the device through the central slots 256 in the. profile plates 232, has threaded on its opposite end a hand-wheel 214 which bears against a projection on the clamping plate 264 and determines the lengthwise position of that member on the supporting pins 266, a ball bearing 216 being interposed between the clamping member and the hand-wheel to reduce friciton. As shown in Fig. 13, the central or thicker portion of the clamping plate 264 extends inwardly between the opposite side walls of the frame 246. and engages the profile plates 252 so that tightening of the hand-wheel 214 clamps the plates ri idly between the left-hand end of the frame and the central portion of the clamping plate,

thereby locking them against heightwise move-' ment. Reverse movement of the hand-wheel will unlock the plates and permit them to be moved heightwise of the device when sufficient pressure is exerted against their upper edges.

The flexible profile device is mounted on the table 514 of the pressing machine and the handle 214 is loosened to release the profile plates. A thin sheet of conformable material 218 such as lead is laid on the surface formed by the upper edges of the plates, as shown in Fig. 12. The table H4 is then raised by the jack I18 to bring the thin sheet into engagement with the bottom surface of the last, thereby forcing the plates to adjust themselves on the rubber support until their upper edges conform longitudinally to the contour of the last bottom, the surface thus formed, however, being fiat widthwise. It will be seen in Fig. 13, that the surface formed by the upper edges of the plates conforms to some extent to the longitudinal contour of the last bottom even before the table is raised, on account of the bed 248 resting on the table. The sponge rubber layer 250 provides a sufiicient yield to allow the plates to move heightwise until their upper edges conform the lead sheet 218 exactly to the lengthwise contour of the last bottom. The profile plates 252 are then locked in position by the clamping plate 264.

While the profile bed is engaging the last bottom in the position shown in Fig. 12, the scale 208 and the contact pin I92 in the collar i8 1 are adjusted in the arm 202 and on the sleeve H2 to determine the thickness of the inner mold which is about to be pressed on the profile bed. At those portions of the foot which are in a substantially normal or balanced condition the inner mold may be made one-eighth of an inch thick although in cases of leg shortage the thickness may be made as great as is necessary to overcome such shortage. Consequently, while the profile bed is contacting with the bottom surface of the last 234, the scale 208 and contact pin I92 are brought into engagement with each other, as shown in Fig. 1.2. This indicates the relative heightwise positions of the last and bed when the two are contacting without an inner mold between them. The collar I84 is firmly secured to the sleeve I12 by the thumb screw I86 and the table is lowered to permit the scale to be adjusted downwardly an amount which corresponds to the thickness of inner molds desired at substantially normal portions of the bottom of the foot.

Figures 12 and 13 illustrate the manner of setting the scale and contact pin to produce an inher mold having a thickness of one-eighth of an inch at substantially normal portions of the foot. When the table is raised again during the pressing operation the bell I98 will ring when the pin 592 contacts with the lower end of the scale 268, thus notifying the operator that the table should be raised no farther.

When the profile bed has been conformed to the contour of the last bottom in the manner described, the table I'M is lowered to permit the material which is to form the inner mold to be placed on the lead plate 273 under the wood last 232. This material comprises ground cork mixed with an adhesive binder such as pyroxylin cement to form a plastic pliable mass 280 which can be readily molded into any desired shape when in a plastic condition and which will dry out to form a firm but somewhat resilient member that will retain its shape indefinitely and accordingly is well adapted for supporting a foot. After the ground cork composition has been spread fairly evenly over the lead plate 278, the table is elevated again until the cork is located only a short distance from the bottom surface of the last. A flexible profile fence 282 is placed on the lead plate 278 and is wrapped around the last to confine the ground cork within an area which conforms to the periphery of the widest portion of the last.

This flexible profile fence, as illustrated on an enlarged scale in Fig. 15, comprises a plurality of thin narrow plates 284 of substantial height provided with centrally located slots 2% through which is threaded a long strip 288 of conformable material, such, for example, as lead, the

thickness or height of the strip being considerably less than the heights of the slots 286 so as to permit a substantial heightwise movement of the plates relatively to the strip. The fence 282 is of sufficient length to wrap around the largest last to be operated upon and, when once conformed to the periphery of the last and to the shape of the upper surface of the profile bed, will tend to retain such shape until force is exerted to straighten the lead strip 288.

After the flexible fence 282 has been arranged around the last, the profile bed is again elevated to press the ground cork composition between the last bottom and the lead plate resting on the upper surface of the bed. As stated above, upward movement of the table is continued until the sale 208 contacts with the pin I92 and rings the bell N35 to indicate that the desired thickness of inner mold has been formed Lmder those portions of the last which correspond to the substantially normal portions of the bottom of the foot. The inner mold pressing operation is illustrated in Figs. 13 and 14, Fig. 14 illustrating how the inner mold appears in cross section at the shank portion of the last and how the edges thereof are confined within the periphery of the last by the flexible profile fence 282. It will also be noted in this figure that, while the upper surface of the pressed plastic material is curved in exactly the same manner as the last, its bottom surface is flat widthwise.

The ground cork composition is allowed to set under pressure for several minutes to insure that it will hold its shape and the profile bed is then lowered from the last and the lead plate 218 is removed from the profile bed with the pressed inner mold 290 (Fig. 16) resting thereon. The lead plate may then be placed on a table or shelf 292 and left for about twenty-four hours to permit the ground cork composition to set thoroughly. After the inner mold has completely dried out so that it will retain its shape permanently, the lower or transversely flat surface thereof is covered with a layer 294 or Celastic (Fig. 17) which is composed of relatively thick fabric material impregnated with a solution of cellulose or a derivative thereof, as more fully described in United States Letters Patent No. 1,256,240, granted February 12, 1918, on an application filed in the name of Stanley Lovell. The Celastic layer 294 is cut to the outline of an insole pattern corresponding in shape to the bottom of the last from which the inner mold was pressed except at the shank where it is preferably cut wider to wrap around the side portion of the inner mold as shown in Fig. 1'7. It is painted with acetone to soften the fibers of the fabric and is then positioned' on and pressed against the bottom surface of the inner mold 290'. When the Celastic layer hardens again through the evaporation of the acetone, it will conform to the shape of the bottom surface of the inner mold and be cemented securely thereto.

The inner mold 298 is now completed except for whatever slight trimming may need to be done at its edges to conform the cork body portion accurately to the outline of the Celastic layer 294 which is cemented thereto. After the trimming operation has been performed the innor mold is mounted on the bottom of the wood last 234, as shown in Fig. 17, and is secured thereto by tacks 295. The upper surface of the inner mold will, of course, fit the bottom of the wood last perfectly since it was pressed from this last. Moreover, the plastic composition from which it position.

has been formed will harden sufficiently to permit the inner mold to remain on the last while the latter is utilized in making a shoe.

Fig. 17 illustrates the last with the inner mold 290 mounted thereon and it will be noted that while the last-engaging surface of the inner mold conforms perfectly to the last bottom, the exposed surface 298 covered by the Celastic 294 is substantially flat widthwise to conform to the shape of the upper surface of an insole in the shoe which is to be made on the combined last and inner mold.

It has been found in some cases that an unbalanced foot will be supported more satisfactorily if the exposed surface 298 of the inner mold is not left perfectly flat and this surface is there fore sometimes rounded slightly by scraping the marginal portions of the inner mold before the Celastic is applied to make it slightly convex. In either case the surface 238 of the inner mold will conform exactly to the upper surface of the insole of the shoe made on the last and thus will prevent any movement of the inner mold relatively to the shoe bottom which would cause discomfort to the wearer or wear out the lining of the shoe. After the shoe has been constructed on the combined last and inner mold, the latter is removed from the last bottom and is ready to be inserted in the shoe to support the foot of the wearer.

As indicated above, the present method also contemplates the production of inner molds for supporting relatively normal feet in stock shoes made on conventional lasts as well as inner molds for supporting unbalanced feet in shoes produced on special lasts made for the feet. This modification of the process is illustrated in Figs. 18 to 22, inclusive. In making an inner mold for a stock shoe the foot is located in a substantially normal weight-bearing position and is pressed into the magnetizable particles 30 in the container 23 of the magnetic molding device to form an impression 299 (Fig. 18) of the lower portion only of the foot. The proper adjustments are made in the supporting member 28 in the manner already described to position the impression in accordance with the position of the upper surface of the insole of a stock shoe which has been properly fitted to the foot. The impression is then lined with a sheet of thin flexible material 56' and the foot is inserted again to conform the lining material to the shape of the impression, after which the power of the electromagnet is turned on full to hold the impression.

In order that the cast of the lower portion of the foot may be subsequently positioned in the pressing device in the same position as that in which it was located when made, a rectangular frame 306 is placed over the impression 299, the opposite sides of the frame extending laterally beyond the side walls of the container 25 and having mounted thereon a pair of adjustable screws 3OI which engage said side walls and may be adjusted to locate the frame 330 in a vertical The forward side of the frame is hinged, as shown in Fig. 18, so that it may be opened to permit the frame to be lifted off the container after a cast has been formed, a pin 392 being inserted through a projection on the hinged wall of the frame and passing through a similar projection on a fixed portion thereof to secure the hinged wall in operative position. The left-hand end of the frame 303, as viewed in Fig. 18, has a lateral projection 334 which carries a spirit level 336 for indicating the exact position of the frame relatively to the horizontal. After the impression has been made in the particles 30 and has been lined with the flexible sheet, the frame is placed over the impression and the screws 3lll are adjusted until the spirit level indicates that the upper edges of the frame are horizontal.

Plaster of Paris is now poured into the impression 233 to fill the latter and the rectangular space above the impression formed by the frame 388, as shown in Fig. 18. The resulting product comprises a cast I20 of the lower portion of the foot having formed on its upper side a rectangular projection 308 the four sides of which will be located in vertical planes when the bottom surface of the cast is positioned in exactly the same position relatively to the horizontal as it was located when made. In other words, the rectangular projection 333 bears a definite relation to the angular position of the bottom surface of the cast I 20 and provides the means whereby the cast bottom may again be located in exactly the same position.

The last upon which the stock shoe was made is indicated in Fig. 19 by the numeral 3H]. A fence of modeling clay 3I2 is formed around the cast in a manner similar 'to that described above to determine the depth of an impression of the lower portion of the last which is to be made in a plaster bed and which is to serve as a bed plate against which to press the inner mold for the shoe. As shown in Fig. 19, the last 3H! is positioned in a molding box or flask 3M by means of three pins 3H3, M8 and 320 located respectively at points corresponding to the normal weightbearing points of the bottom surface of the foot, these points being at opposite sides of the ball portion of the foot and at the central part of its heel portion. The pins 3E6 and 3I8 are equal in length so that the last 3H3 will be balanced at the forepart in the same position as the foot was positioned when the impression was made in the magnetic box. The pin 323, supporting the heel portion of the last, is of sufficient length to support the heel end of the last in the same position as the foot will be supported in the stock shoe, the heel height of the shoe having been previously measured by means of the measuring device 36 illustrated in Fig. 2. Plastic material 322 is now poured into the flask to cover the lower portion of the last up to the clay fence (H2. The plastic material is allowed to set and the last is then removed. The resulting mold or bed plate 324 is illustrated in Fig. 21, it being shown in that figure positioned on the table I14 of the pressing device with the cast I29 of the lower portion of the foot located in operative position relative thereto. The cast I20 is held in the pressing device by means of a slide 326 mounted in the guide- Ways I42 and located transversely thereof by means of a spring-pressed pin I48. The lower side of the slide 323 has projecting therefrom a pair of arms 328, 329 which support on their lower ends a flat horizontal plate 330 having a rectangular flange or frame 332 projecting downwardly from its bottom surface. The downward- L ly projecting frame 332 is adapted to fit over the rectangular projection 398 on the cast I20 and is provided at its opposite sides with binding screws 334 for clamping the projection rigidly in the frame. In this way the cast of the lower portion of a foot may be mounted in the pressing device so that its bottom surface bears exactly the same relation to a plane of reference such as the horizontal as the impression in the magnetic box boreto such plane when made. Moreover, the

bottom of the cast is also located in the same angular position as the impression of the lower portion of the last 3H1 in the bed plate 324 is located.

The scale 208 and the contact pin I92 are adjusted to bring them into engagement with each other while the bottom surface of the cast is engaging the impression in the bed plate. The table is then lowered and the scale is moved downwardly an amount sufficient to produce an inner mold of the desired thickness at the three normal weight-bearing points of the bottom surface of the foot. The impression is next lined with a layer of Celastic material 336 and ground cork mixed with pyroxylin cement to form a plastic composition 338 is spread over the Celastic layer. The table H4 is elevated to cause the bottom surface of the cast I20 to press against the plastic composition to form the inner mold. The parts are left in this position for a period of time sufficient to permit the material of the inner mold to set so that it may be removed .from the bed plate, after which the table I'M is lowered and the inner mold with the Celastic layer adhering thereto is removed. Fig. 22 illustrates the inner mold 340 which has been formed in the manner shown in Fig. 21 and shows the Celastic covering the side portion of the inner mold at its shank portion.

The inner mold 340 is now complete except for such trimming or finishing operations as may be necessary to remove any projecting edges of the Celastic material and to smooth off that portion of the toe end of the inner mold which extends beyond the end of the cast I20 in Fig. 21. After the finishing operations have been performed the inner mold is placed on a shelf or rack to dry for about twenty-four hours before it is used in the shoe. The present inner mold, like that produced from a full sized cast of a foot, has a bottom surface which conforms in shape to the upper surface of the insole in the shoe in which it is to be used. Since the upper side of the inner mold was shaped from a reproduction of the bottom of the foot, this side will be identical with the shape of the foot when the latter is in the position it assumes in the shoe while supporting the weight of the body. Consequently, the inner mold will have no tendency to slip either heightwise or longitudinally to cause discomfort to the wearer. Moreover, since all portions of the inner mold contact with the shoe bottom, the weight of the body will not distort the shape of the upper surface of the inner mold and thus reduce its effectiveness as a support for the foot. As stated above, inner molds of this type are adapted to be inserted in shoes which have been made on regular or conventional lasts. If desired the upper or foot-engaging surface of the inner mold may be covered with a thin layer of fabric material to prevent the stocking from contacting directly with the ground cork composition although such a covering is not necessary since the composition drys out thoroughly and is not noticeably affected by heat or moisture.

In cases where the longitudinal arches of the feet may require more rigid supportto hold them in proper position, for example, where a foot has been unbalanced or defective. in this respect for a long period of time so that the returning of its arches into a properly balanced position may require an inner mold which is relatively inflexible at the shank portion, a shank piece or stiffener may be molded into the inner mold during the pressing operation, thereby causing the shank portion of the inner mold to become considerably stiffer than the heel and toe portions thereof so that it will afford the desired support for that portion of the foot.

Fig. 23 illustrates in section how a shank stiffener 342 of metal, fiber or other suitable material may be incorporated in an inner mold 344 which corresponds in all other respects to the inner mold shown in Fig. 22. The shank stiffener 342 is preferably bent into approximately the desired shape longitudinally and is located in the proper position in the ground cork composition 338 before the latter is pressed between the supporting bed and the cast I20 or, in cases where it is used, against the wood last 234. When the material of the inner mold has completely dried out, the shank piece 342 will be permanently embedded in its shank portion, as shown in Fig. 23, thereby rendering that portion more rigid longitudinally than the heel and toe portions of the inner mold and providing a firmer support for the shank portion of the foot.

Having described the invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. That improvement in methods of making inner molds for shoes which comprises locating a molding member at a predetermined angle to a plane of reference, said member having a molding surface thereon which is an exact reproduction 'of the bottom surface of a foot when the foot is expanded under the weight of the body, locating a second molding member in a predetermined relation to the first, placing plastic material between said molding members, and forcing one of said molding members toward the other while so located and thereby molding said plastic material to a shape appropriate for supporting a foot, the proper weight bearing position of which is the same as the position in which the first-mentioned molding member is located relatively to the plane of reference.

2. That improvement in methods of making inner molds for shoes which comprises locating a molding member relatively to the horizontal in accordance with the natural position of a particular foot when the foot is supporting the weight of the body, said molding member being an accurate reproduction of the bottom surface of the foot when the foot is expanded under the weight of the body, locating a second molding member in a predetermined angular relation to the first molding member, said second molding member conforming lengthwise to the longitudinal contour of the first molding member but being relatively flat widthwise, and, while maintaining the angular relation between said molding members, pressing plastic material therebetween to produce an inner mold adapted to support said foot in its proper weight bearing position.

3. That improvement in methods of making inner molds for shoes which comprises providing a pair of solid molds having coacting surfaces thereon shaped to produce an inner mold of predetermined shape and dimensions, locating said molds so that said surfaces bear a predefined angular relation to each other, placing plastic material on one of said molds, and, while maintaining said predefined angular relation between said surfaces, moving them toward each other to compress the plastic material to form an inner mold.

4. That improvement in methods of making inner molds for supporting feet in shoes which comprises providing a pair of molds of solid material, one of said molds having a molding surface thereon which conforms accurately to the shape of the bottom surface of a foot when the foot is expanded under the weight of the body, and the other of said molds having a molding surface thereon which conforms to the shape of the upper surface of an insole in a shoe appropriate to said foot, locating said molds in a predetermined angular relation to each other, depositing plastic material on one of said molds, and, while maintaining said angular relation between said molds, moving them toward each other a predetermined distance to press the plastic material to produce an inner mold.

5. That improvement in methods of making inner molds for shoes which comprises initially locating a foot relatively to the horizontal in a correct weight bearing position and placing the foot under the weight of the body, locating a mold the molding surface of which is identical to the shape of the bottom surface of said foot when the foot is expanded under the weight of the body in a corresponding position, locating a second mold in a predetermined angular relation to the first mold, the molding surface of said second mold conforming accurately to the inner surface of an insole of a shoe appropriate for said foot, depositing plastic material on said second mold, and moving said second mold toward the first mold while maintaining said predetermined angular relation between said molds to compress the plastic material and thereby produce an inner mold appropriate for supporting the foot in its correct weight bearing position in said shoe.

6. That improvement in methods of making inner molds for shoes which comprises locating a last relatively to the horizontal in a position corresponding to that in which a foot should be located relatively to the horizontal in a shoe when in correct weight bearing position and when supporting the weight of the body, said last having a bottom surface identical in shape with the bottom surface of said foot in weight supporting condition, locating a molding member in a predetermined angular position with respect to the bottom surface of said last, said member having a molding surface thereon which conforms longitudinally to the contour of the last bottom but is flatter widthwise, placing plastic material on said molding member, and, while maintaining the predetermined angular relations of the last and molding member, moving them toward each other to compress the plastic material and thereby produce an inner mold having an upper surface which is complemental to the bottom surface of said foot when the foot is supporting the weight of the body, and having alower surface complemental to the insole in a shoe.

CLIFFORD K. MACDONALD.

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2530737A (en) * 1945-10-16 1950-11-21 Sherwin Frank Shoe molded to shape of foot
US2581489A (en) * 1948-04-09 1952-01-08 United Shoe Machinery Corp Apparatus for making casts
US2667237A (en) * 1948-09-27 1954-01-26 Rabinow Jacob Magnetic fluid shock absorber
US2708773A (en) * 1951-08-06 1955-05-24 Herman W Richter Method for making molds
US2711558A (en) * 1951-01-23 1955-06-28 United Shoe Machinery Corp Molding apparatus
US2973529A (en) * 1955-02-16 1961-03-07 Jack J Silverman Technique for making shoes
US2979808A (en) * 1957-01-31 1961-04-18 Orenda Engines Ltd Method and apparatus for securing skin to a core
US3497892A (en) * 1968-06-03 1970-03-03 Usm Corp Contoured insoles
US4327046A (en) * 1979-12-07 1982-04-27 Southern Research Institute Method for producing a rigid, shaped mass support system

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2530737A (en) * 1945-10-16 1950-11-21 Sherwin Frank Shoe molded to shape of foot
US2581489A (en) * 1948-04-09 1952-01-08 United Shoe Machinery Corp Apparatus for making casts
US2667237A (en) * 1948-09-27 1954-01-26 Rabinow Jacob Magnetic fluid shock absorber
US2711558A (en) * 1951-01-23 1955-06-28 United Shoe Machinery Corp Molding apparatus
US2708773A (en) * 1951-08-06 1955-05-24 Herman W Richter Method for making molds
US2973529A (en) * 1955-02-16 1961-03-07 Jack J Silverman Technique for making shoes
US2979808A (en) * 1957-01-31 1961-04-18 Orenda Engines Ltd Method and apparatus for securing skin to a core
US3497892A (en) * 1968-06-03 1970-03-03 Usm Corp Contoured insoles
US4327046A (en) * 1979-12-07 1982-04-27 Southern Research Institute Method for producing a rigid, shaped mass support system

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