US2242817A - Manufacture of footwear - Google Patents

Description

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. j g' L W@) Y o) 1 lvwerow" Wrecl 7 5007101! arq Patented May 20, 1941 UNETED STATES FATENE @f'FEQE MANUFACTURE OF FOOTWEAR Alfred W. Donovan, Quincy, Mass.

Application June 23, 1939, Serial No. 280,763

1 Claim.

This invention pertains to the manufacture of footwear, and relates more especially to an improved bottom structure for shoes and to a meth- 0d of making such an improved bottom structure.

Patent No. 2,190,512, issued to Alfred W. Donovan, on February 13, 1940, points out how desirable it is that all shoes made to the same last shall be as nearly identical in fit, size and outward appearance as possible, and suggests a method of treating an outer sole, assembled with other parts of the shoe bottom structure, so as thereby to obtain a more uniform product than has heretofore been possible.

The patent to Donovan No. 2,147,887, dated February 21, 1939 points out (in particular with reference to the manufacture of shoes in which provision is made for metatarsal support) how necessary it is as respects good shoe making practice that the inner bottom structure, that is;

to say, the lasted shoe bottom exclusive of the outer sole, be accurately contoured if the foot of the user is to be properly supported. While such accuracy in inner bottom structure is requisite in shoes of the metatarsal supporting type, it should be recognized that accuracy in the dimensions and contour of such structure is alsoinner bottom structure with which the outer sole contacts.

Patent No. 2,213,066 issued to Alfred F. Donovan on August 2'7, 1940 discloses desirable procedures, in particular the accurate premoulding of the inner sole, as contributing factors in the preparation of an accurately contoured and otherwise desirable inner bottom structure.

One object of the present invention is to provide an improved mode of making shoes such as not only to provide for initial fine appearance and uniformity of shape and dimension, but to ensure the retention of such features during a substan tial period of use.

In the attainment of this object, it is contemplated that the outer sole will be so preshaped before assembly with the inner bottom structure that in the operation of uniting it to the inner bottom structure, for example by sewing it to a welt, no substantial stressing or deformation of the outer sole is necessary in effecting a film and close union of the parts. Thus fortuitous irregularities in the final product due tothe imposition of such stresses on the outer sole (which commonly occur in usual shoe making practice) are avoided, and greater uniformity and durability in the finished product is assured.

At this point it may be observed that, in accordance with the more usual shoe making practice, the outer sole is substantially flat or at least but slightly moulded when it is assembled with the inner bottom structure preparatory to the sole laying operation, and that much difficulty is experienced in closing the outer sole snugly against the inside shank of the inner bottom structure in sole laying, leveling and stitching. In the endeavor to conform the outer sole to the deep inside shank during these operations, there is a tendency to displace the opposite ends of the sole and to impose initial stresses upon the material of the sole or the attaching. means. Such initial stressing of the material tends to cause distortion of the shoe when worn and substantially reduces durability. Moreover, the updrawing of the sole material into the arch of the shank tends to shorten the sole so that it is necessary to use a sole of a size sufficient to allow for this lessening in length resultant from conforming it to the shank.

In accordance with the present invention, the margin only of the sole at the shank (usually only the inner margin) is subjected t. an actual stretching operation, thereby providing a surplus of material at this point capable of fitting snugly against the shank of the inner bottom structure without further stresses or distortion. This stretching is accomplished without robbing material from the opposite side of the sole such as would change the outline of the sole and Without throwing its opposite ends out of alignment, and results in the provision of a surplus of sole material at the margin of the shank which great- 1y facilitates the laying and leveling operations. It further results in a saving in cost, due to the permissive use of a cut sole of a size or sizes shorter than usually necessary, for in accordance with ordinary practice the entire sole is shortened in the operation of closing the sole snugly against the shank. The preshaping of the sole also reduces the cost of cementing prior to sole laying because the material at the shank lies snugly and securely against the welt and inseam and does not require so much cement as usual to hold the sole in place during subsequent rough rounding and stitching.

The invention further contemplates such treatment of the outer sole before it is assembled with the inner bottom structure as to ensure a high degree of flexibility at the forepart of the outer sole, such increased flexibility being obtained without substantial weakening of the material of the outer sole and without removing any of its substance.

Further, with the above object in View, the invention contemplates, at least as an optional feature, the provision of an inner bottom structure whose bottom surface is preshaped and. contoured to be accurately complemental to the upper surface of the finished outer sole so that when the parts are assembled, the shape of the outer sole will not be substantially altered by the configuration of the bottom surface of the inner bottom structure with which it contacts.

Another feature of the invention resides in the employement of a contouring form for imparting the desired surface configuration to the outer sole (and also, if'desired, to the inner bottom structure) the formbeingof a substantially transparentzmaterial, thereby to enable the operator to observe the appearance of. the surface of the shoe with which the form contacts while the form is still in place and thus to determine the degree of perfection of the operation.

While the invention has herein been illustrated by way of specific example as embodied in a Goodyear welt shoe, it isto be. understood that in so far as its broader aspects are concerned it is equally applicable to shoes of other types, for

instance, McKays, stitch-downs, compos, Littleways, etc;

Other and furtherobjects and advantages of.

the invention will be pointed out hereinafter in the following more detailed description and by reference to'the accompanying drawings, wherein Fig. 1 is a;plan view of an outer sole blank; Fig. 2.is a' section onthe line 22 of Fig. 1; I Fig. 3 is a bottom plan view, of, the outer sole as it appears at the completion'of the shank stretching and forepart .flexing operations;

Fig.14 is a section onthe line 44 of Fig. 3;,

. Fig; .5 is a section on the line 5-5 of Fig. 3, indicating the longitudinal contour of the outer sole at the completion of the stretching and flexing operations;

Fig. 6 is a-fragmentary vertical section, taken longitudinally of the outer sole, illustrating the step of stretching the'margin of the sole at the shank;

Figure '7 is'a' fragmentary diagrammatic sectional view taken at right angles to the plane of Fig. 6;

Fig. 8 is a fragmentary diagrammatic vertical section'longitudinal of the outer sole, illustrating thestep of flexing the forepart of the outer sole;

Fig. 9 is'a viewssimilar to Fig. 6, but illustrating the :use of flexing apparatus of a different type;

Fig. 10'is a' planview of an inner sole of the Goodyear welt type such as may be used in shoes made in. accordance with the present invention;

Fig. 11 is a fragmentary transverse section through a lasted shoe of the Goodyear welt type showing thewelt secured to the rib and with a mass. of plastic bottom filler disposed in the central space defined by the rib;

Fig. 12 is a view similar to Fig. 11, but showing thebottom of the lasted shoe as it appears after thebottom has been contoured;

Fig. 13 is a diagrammatic side elevation of a press suitable for contouring the bottom of the inner bottom structure;

nal axis A-A of the sole blank being indicated by a broken line, said axis substantially defining the greatest dimension of the blank. The blank is substantially flat and of appropriate shape and size for the shoe to be made, although, as hereinafter pointed out, the size of this blank may be somewhat less than that of a sole blank intended for the same use but which is handled in accordance, with usual prior methods. While the present invention is particularly useful in the manufacture of shoes having leather outer soles, it is broadly applicable to soles of other materials.

Having provided the blank I as above suggested, the blank may be subjected to any of the usual preliminary operations, for example, to a channeling operation if it be desired to form a Good year type sole. The blank is now tempered, for instance by placing it in a humidifying chamber in which definite moisture conditions are maintained, thereby to make the blank pliable and to some degree plastic.

After tempering, the blank is subjected to a shank stretching operation whereby its marginal portion 2 at the inner edge of the shank 3 (and, if desired, the other margin as, Well) is so elon gated that, when the outer sole is applied to the inner bottom structure, its shank portion will fit snugly against the shank portion of' the insole throughout its entire width and without necessitating any other deformation of the outer sole.

To this end the tempered blank is preferably subjected to the action of stretching dies 5 and 6 or equivalent means. The dies shown have opposed surfaces which are so contoured as to stretch the margin only of the blank at the shank portion without stretching the material substantially at other points and without substantially changing the peripheral contour (in plan) of the blank or sole or displacing its front-to-rear ends relatively to the axis A--A.

As herein illustrated, the lower die 6 has a curved upper surface whose contour is substantially exactly like that which it is desired to impart to the inner margin, for example, of the sole blank, said surface comprising the two low points 1 and 8 and the intermediate high point 9. The upper, relatively movable die 5 has a curved sole-contacting surface including the high portions it and H and the intervening low portion or hollow I 2, it being noted that the concavity represented by this lower portion [2 is somewhat deeper than the elevation 9 of the die 6. Thus, as the dies are brought together with the sole disposed between them, the marginal material of the shank is first bent over the elevation 9 and second is gripped at longitudinally spaced points M and N between the points 1 and I9, and 8 and H, respectively, and third, as the dies continue to approach and compress the material of the stretching takes place after the sole has been firmly gripped at the points M and N, respectively, so that during the stretching the sole cannot change its original peripheral configuration, as viewed in plan, nor twist with respect to the axis AA. The dies are so contoured that the degree of stretch imparted to the sole material progressively increases outwardly from a point to one side of the axial line A-A to the edge of the sole where maximum stretch takes place. Preferably the dies 5 and 6 are so shaped that a pair of soles may be stretched in a single operation, as illustrated in Fig. 7.

While the sole with its stretched shank as just described may now be applied directly to the inner bottom structure, it is preferable to subject the sole to a flexing operation such as to increase the flexibility of its forepart portion and thus impart to the newly completed shoe a degree of comfort which is ordinarily to be found only in shoes which have been subjected to breaking With this in View, the tempered sole is subjected to a severe bowing at its forepart such that the grain side G is stretched and permanently elongated relatively to the flesh side. Such stretching of the close-textured grain side has been found to impart a high degree of flexibility, although without necessitating removal of any of the material of the sole or otherwise appreciably weakening it or lessening its durability,

For stretching the grain side of the sole, apparatus such as illustrated in Fig. 8, for example, may be employed. This apparatus comprises a lower die or matrix 13 having the high points M and i5 and an intervening deep and narrow trough-like depression smoothly curved at its bottom. With this matrix cooperates a die I6 having a smoothly rounded lower end or nose I].

The tempered sole is laid across the high points It and iii of the matrix with the grain side of the sole down and so that the trough-like depression of the matrix extends transversely of the forepart of the sole. The die I6 is now forced downwardly against the flesh side of the sole, thereby forcing the sole down into the depression in the matrix, thus forming a deep concavity in the flesh surface of the sole and imparting a convex contour to the grain surface. In causing the grain surface of the tempered sole to conform to the curved bottom of the depression in the matrix, the grain surface is stretched while the flesh side is concomitantly depressed. The stretching of the grain surface of the tempered sole results in a permanent loosening of the fibers which comprise the grain side, and although the treatment does not apparently rupture the fibers, it nevertheless imparts a degree of flexibility to the sole which is substantially greater than that of the untreated sole.

Instead of the rigid matrix I3 of Fig. 8, a fiexible matrix 13 designed for the application of fluid pressure, may be employed, as illustrated in Fig. 9. The matrix l3 consisting of an inflatable bag of appropriate flexible material, for example rubberized fabric, is conveniently supported in a rigid box-like receptacle I8, and has a fluid admission pipe is leading from a suitable controlled source of pressure fluid. The die 66 is arranged to move toward and from the matrix 13 and has a downwardly directed cylindrically curved nose H The sole is disposed on the matrix i3 and the die Iii is moved downwardly so that its nose l'l contacts and extends transversely across the forepart of the sole blank at its flesh side and presses the latter down into the matrix bag. The die l6 is now held in this position while pressure fluid is admitted to the interior of the matrix bag Ili thereby inflating the latter and forcing the sole blank to curl upwardly about the nose Il thereby permanently stretching the grain surface of the sole.

In accordance with one desired embodiment of the invention, the bottom surface of the-lasted shoe is accurately contoured before the outer sole, prepared as above described, is assembled with it.

While unusually good and uniform results are attained merely by the use of premoulded inner soles such as described in the above patent to Alfred F. Donovan, No. 2,213,066, it is contemplated that even finer effects may be attained if, after the shoe has been lasted, the inner bottom structure is subjected to moulding pressure such as to give it a contour substantially identical with that of the outer surface of the outer sole of the completed shoe.

Thus, referring to a shoe of the Goodyear type for example, but without limitation thereto, Fig.

.11 shows a shoe in transverse section having the upper U and the insole I mounted on the last L, the insole having the sewing rib R to which the welt W is secured by the inseam stitches S. The space at the center of the shoe bottom defined by the closely trimmed rib R, is supplied with a mass of plastic bottom filler B.

. The inner bottom structure thus prepared and with the sewing rib trimmed as smoothly as it is practicable to do, is now subjected to static pressure in a press P (Fig. 13), (for example, a press of the kind more fully described in Patent No. 2,190,512, issued to Alfred W. Donovan on Feb. 13, 1940) wherein the under surface of the inner bottom structure is arranged to rest upon a contouring form of the general type disclosed in the patent just referred to. While the contouring form may be of any of the materials and constructions suggested in said last-named patent, it is preferred to use a form 20 such as herein illustrated in Fig. 16. This form has a smooth, glossy contouring surface 2| and an under surface 22 which may be flat or of any other desired configuration and is of a rigid, tough, but preferably transparent material such, for instance, as the synthetic resin known as Lucite, which is understood to be a polymer of methacrylic acid. This material is capable of withstanding heavy pressure without permanent deformation; takes and retains a high gloss; is readily shaped to the desired contour; and in view of its transparency, enables the user toobserve through its substance the bottom of the shoe with which it engages. Thus, if he so desire the operator can remove the shoe and form from the machine and by looking through the form ascertain whether the shoe bottom has unduly high or low spots, the existence of air bubbles between the form and shoe bottom, etc., thus enabling him to correct defects before the completion of the operation.

The result of this contouring operation as applied to the bottomof the inner bottom structure is to smooth and compact the bottom structure, compressing the filler B and removing irregularities in the sewing rib and welt, and imparting to the bottom an accurate contour which is a substantial replica of that of the outer surface of the outer sole of the finished shoe. The result of this operation is indicated more or less diagrammatically in Fig, 12.

.Theouter sole is-now assembled with the inner bottomstructure and laid, preferably by the use of a fluid-pressure press of the type illustrated in Fig. 13. In thus laying the sole against the' After the outer sole has been laid, the shoe is,

placed in a second press P, which may be substantially like the press P (or it may be returned to the press P for this operation if preferred), and while the outer surface of the outer sole contacts the contouring form 2!], pressure is applied such as to impart to the bottom of the outer sole substantially the final desired shape and finish. i

If the shoe be of the compo or cement type, the laying and final contouring operations may be combined, the sole being assembled with the inner bottom structure with interposed adhesive and then subjected to a single operation in the press P with the outer sole contacting the contouring form 20. 7

Although the process, including all of the several steps above enumerated and in the sequence specified, is very desirable, it is to be understood that in its broader aspects it may include a, lesser number of steps or that it may include a diiferent order of steps, and that any and all such variations in the number or order of steps, or the substitution of equivalent steps, are to be regarded as falling within the purview of the invention as defined in the appended claim.

I claim:

Method of makingshoes of the Goodyear type wherein an inner sole, having a sewing rib at its under side, is first accurately premoulded so as to conform its upper surface to the contour of the bottom of the last with which it is to be used and is then assembled, together with an upper, upon the last and the shoe is lasted, and wherein a welt is then secured to the sewing rib, the inseam is trimmed and a mass of plastic filler is deposited upon the under surface of the inner sole in the space defined by the inseam, and wherein there is provided an outer sole having its inner margin at the shank portion so permanently elongated and shaped that when the outer sole is assembled with the inner bottom structure of the shoe said marginal portion of the outer sole will fit snugly against the shank portion of said bottom structure and wherein, after assembling the outer sole with and attaching it to the welt, the outer surface of the outer sole is subjected to pressure in direct contact with a rigid contouring form whose sole-contacting surface is smooth and glossy and of substantially the exact contour, but in reverse, of the desired finished surface of the outer sole, characterized in that prior to assembly of the outer sole with the inner bottom structure of the shoe the latter is so treated by the application of pressure as to compact it and concomitantly to impart to its exposed surface a contour which is a substantial replica of the contour of the outer sole of the finished shoe.

ALFRED W. DONOVAN.

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