US3309722A - Apparatus for preshaping uppers - Google Patents

Description

March 21, 1967 A. A. STADEN www@ APPARATUS FOR PRESHAPING UPPERS Original Filed Feb. 4, 1965 2 Sheets-SheG/rl l March 21, 1967 A, A, STADEN APPARATUS FOR PRESHAPING UPPERS 2 Sheets-Sheet 2 Original Filed Feb. 4, 1965 United States Patent htice 3,309,722 Patented Mar. 21, 1967 3,39,722 APPARATUS FOR PB ESHAPENG UlPElS Alfred Alexander taden, Wellingborough, England, as-

signor to The British Boot, Shoe and Allied Trades Research Association, Kettering, Northamptonshire, England, a British association Original application Feb. 4, i965, Ser. No. 439,327. Bi-

vided and this application Oct. 4, 1965, Ser. No. 692,322 Claims priority, application Great Britain, Feb. 16, 1964, 5,410/ 64 9 Claims. (Cl. 1254.1)

This invention relates to the treatment of leather with a view to pre-forming the same, whereby the leather may more readily be shaped to a desired contour as, for example, in making an upper part of a shoe. This application is a division of my co-pending application Ser. No. 430,327 tiled Feb. 4, 1965.

The conventional method of shaping an upper forepart depends upon the application of force to draw the upper material over a last and to fasten it by mechanical means in this stretched condition. A measure of setting to the desired shape is achieved either by the mere lapse of time or by the application of means, such as heat treatment, to hasten this result. However, the leather is not always as amenable as might be desired to this deforming treatment, and powerful forces are often required to pull the leather into shape, which may cause a deterioration in the properties of the leather as well as apparent damage.

lt is an object of the present invention to provide a method and apparatus for preshaping leather, so that the l leather may more readily assume the required contour. Another object of the invention is to provide `apparatus whereby the stretching of the leather which is entailed in causing the leather to assume a desired contour, may be accomplished more satisfactorily than by pulling the leather edgewise into contact with a last. Yet another object is to provide means whereby leather pieces may be lasted without having to sud-er the application of unduly high tension.

The invention consists, broadly, in a method of preshaping a piece of leather in which the leather, supported in a generally flat condition at spaced positions at or adjacent its periphery, is subjected to localized stretching by lateral displacement between said positions. Generally, this displacement will be accomplished by relative movement between the supports for the leather and a plurality of mould parts. These mould parts may be arranged for separate movement, but may more conveniently fbe arranged for movement in unison, and may represent portions of an undulating mould surface.

ln forcing a leather piece to assume a desired contour, such as the forepart of a shoe upper, the leather is conventionally held at its periphery and pulled against a mould surface (last), the mould or last surface protruding as a whole and displacing the main body of the leather laterally of the plane, corresponding generally to the last sole plate, where the leather is gripped at its periphery, However, it is found that the leather is not stretching uniformly, and in some places may even be subjected to slight compression. The stretching of the leather is to a large extent localised and occurs in separate regions situated between predetermined parts of the leather periphery. It is found that the leather may be stretched in the desired manner and thus preshaped, much more eiiiciently, that is to say, more uniformly and/ or with a lesser pull, if the leather is held at those positions where it is to be stretched least or not at all, and the stretching displacement then brought about by a mould which bears little resemblance to the contour which is ultimately required. However, if this preshaped leather part is now lasted or otherwise moulded in substitution for a leather part which has not been given this treatment, far readier conformity with the last or other mould is achieved.

In this connection it will be understood that the expression preshaped does not mean that the leather necessarily assumes and retains some predetermined shape, but that the leather is stretched selectively in certain regions, corresponding to those regions where the maximum stretch is required in the ultimate shaping of the leather, so that the leather is no longer flat but exhibits predetermined regions of distension, through retention of part at least of the stretch to which it has been subjected.

In what is perhaps the Amost important application 0f the invention, an upper lforepart is preshaped. The toe, the inside Waist and the outside waist portions of a footwear upper forepart form three corners of a triangle. Analysis of lthe distortions undergone by the leather in the course of normal lasting indicates that the material between the corners of this triangle should be stretched, whilst the centre part of the triangle should if anything be slightly compressed. In this case, therefore, the generally triangular leather piece will be gripped at its apices and held in a generally flat condition, and then displaced by a mould having three mould parts in the form of lobes which together suggest a clover leaf, the surface contours being such that the lobes will -cause the material between the gripped positions to stretch when the mould is forced between them, whilst leaving the material at the centre of the triangle relatively undisturbed.

Optionally, provision may be made for retractive movement of the jaws or other gripping devices for holding the leather at its periphery, for imparting additional stretch.

Whilst a mould for preshaping shoe upper oreparts will generally have three lobed mould parts as just described, it may have only two (for stretching the regions between the toe and waist), or it may have `four if provision is made for forming a bulge at the toe.

It will in general be desirable to incorporate some provision for increasing the retention of the localized distension of the leather. This will generally entail the application of heat, and to this end, provision may be made for heating the mould parts. Alternatively, the mould parts may -be used as an electrode of a dielectric heating device, or provision may be made for passing steam or hot air through the mould parts, which in this case will remain permeable. In addition, or instead, an application of moisture may be made. Thus, the upper may be preformed in a mulled condition and dried, to some extent, on the mould.

Where the mould is heated, the temperature employed may..well exceed C. for normal full chrome leathers. The leather may in this case be wetted on the ilesh or innerside with water (with or without wetting agent) before tting to the mould, or alternatively, a membrane .of a suitable substance such as paper, gauze or fabric may be pre-wetted with water with or Without wetting agent andY interposed between the upper material and the heated mould. In yet another alternative, the leather is stretched over the heated mould, and the leather surface not in contact with the mould is wetted. These do not of course represent all the variants which will be apparent to those skilled in the art; for example, the leather when stretched over the mold (whether heated or not) may be heated on its exposed face, or a heated, complementary mould member may be pressed down over the exposed leather face.

Normally the mould parts will make contact with the flesh side of the leather, although similar results may be obtained if contact is made with the grain side.

By stretching a shoe vamp in flat form between three .jaws holding the leather at its apices, whilst the leather is deformed by pressure applied from a mould designed to stretch the material along the sides of the triangle, and especially by using this same apparatus to set the deformation so produced, a preformed forepart may be obtained which is enormously improved as regards its lasting properties.

Whilst apparatus of the invention has special significance in relation to leather, other materials such as plastic uppers may be pre-stretched in a like manner.

The location and extent of strains which need to be applied to a shoe upper to cause it to conform to the surface of a last can be determined by flattening shells of the last made from suitable material such as tape or plastic material. Such shells which will be familiar to those acquainted with the art, are made by covering the whole or part of the last surface with a suitable material which is afterwards removed to provide a representation of the surface contours of the last. In order to achieve the flattening of the shell, the material must of course be shrunk in various regions, and this can be accomplished for example by pleating it. The extent of the required shrinkage can then be measured, and in this way a pattern can be prepared showing the starting contour and the location and degree of stretch required so to pre-shape the initially flat upper material that it will conform to the last with a minimum of strain. To achieve this, however, it is necessary to strain the upper in a manner which is not achieved by existing lasting machinery, but which is readily achieved by the method and apparatus of this invention.

The invention will be described further with reference to the accompanying drawings, of which:

FIGURE 1 is a plan view of a leather vamp showing the magnitude and direction of required stretch;

FIGURE 2 is a view similar to FIGURE l but of a different pattern;

FIGURE 3 is a view of a simple machine for preforming uppers by means of an undulating mould;

FIGURE 4 is a View of the upper part of the machine with a pre-heated mould fitted in position, and

FIGURE 5 is a view similar to FIGURE 4 but showing the machine in operation.

The vamp shown in FIGURE l comprises a tongue 1, tab points 2, a toe portion 3 and marginal side portions generally indicated by the reference numeral 4. The feather line, that is to say the line along which the lasting margin is folded under the last, is indicated by the dotted line 5. A forepart pattern such yas that shown in FIGURE 1 can in considerable measure be generated by forming a skin or shell of exible material on the last over the required area, removing the skin or shell and flattening it. In order to accomplish this attening, it will be found that extensive pleating or wrinkling of theV flexible material is necessary. This corresponds in effect to a compression of the material, and the direction and extent of the :more important lines of compression are indicated by reference numerals 6 and 7 in FIGURE 1. Correspondingly, to generate the original shell, a leather pattern cut to the shape shown in FIGURE 1 requires to be stretched in the corresponding direction and to the corresponding extent. Similarly in FIGURE 2, where the same numerals identify corresponding parts of the vamp, which in this case has no tongue, the marginal portions 4 are stretched over the region indicated from an initial length of 4 inches to a nal length of 41/2 inches, whilst the region of the tab points is given a stretch of the order of 1%2 of an inch, in a direction at right angles to the centre line of the vamp. These two directions of stretch are not, of course, by any means precisely at right angles to one another but they are generally transverse to one another. Where the vamp has a tongue, this may be stretched at right angles to its centre line to a degree increasing towards the free end of the tongue. The stretch referred to in the vicinity of the tab points may be localised as shown, as more generally distrib-uted along a line transverse to the vamp centre line.

In stretching a vamp such as shown in FIGURE l or FIGURE 2, it may be found advantageous not to stretch the lasting margin itself to the extent indicated, or at least to arrange that the stretch is not retained to the same extent as it is above the lasting margin.

The machine of FIGURES 3-5 comprises a table-like frame 3) incorporating a shelf 3l carrying a ram or jack 32. The jack incorporates an extensible rod 33 and a rocker 34, operation of which in an up and down direction causes the rod 33 to extend in a well known fashion. The frame 30 also incorporates a top 35 carrying three sets of jaws 36, 37 and 38. The jaws 36 and 37 are supported by blocks 39' and 4t) respectively and each associated with a handle and screw mechanism 41 and 42 respectively whereby the jaws 35 and 37 may be moved. Each of the jaws points towards a generally central position above the rod 33.

A mould member 43 detachably rests on the top of the rod 33. This mould member is of undulating form, comprising three rounded lobes 44, 45 and 45 arranged, as shown in FIG. 4, in trefoil form, the lobes being reduced in height from the outer edges toward the center. A handle 47 is also provided, whereby the mould member may be conveyed from an oven to the top of the jack 32. In use, a leather upper forepart 4S, similar to the forepart illustrated in FIGURE 2, is gripped at its apices by the jaws 36, 37 and 38. Jaws 3S grip the toe part, whilst jaws 35 and 37 grip the waist portions. The pre-heated mould member 33 is positioned as shown in FIGURE 4, before fitting the leather forepart, and afterwards the jack rocker 34 is operated to lift the mould 43 and press it against the leather as illustrated in FIG- URE 5.

To facilitate stretching the leather it may be in an already moistened or mulled condition prior to fitting in the jaws. To increase retention of the stretch imparted to the leather, the latter may if desired be additionally moistened after it has been stretched by the mould member 43. In either case, the heat of the mould member 43 dries the leather, and when it is deemed sufficiently dry it is removed from the machine.

Generally', it will be found sufficient to position the leather manually in the jaws, the screw mechanism 41 and 42 serving to adjust the machine for different sizes of vamp. If desired, however, these mechanisms may also be used to stretch the leather additionally after the jaws have been closed.

The machine shown in FIGURES 3-5 illustrates the principles involved. In a factory machine, the actuation of the jaws and movement of the mould would be by pneumatic, hydraulic or other driven and automatically regulatable means.

1 claim:

1. Apparatus for preshaping an upper forepart blank comprising spaced clamps for engaging the blank adjacent its toe and waist manginal areas and positioned to support the blank in a taut substantially flat condition; a mould having a plurality of lobes positioned to engage selected `marginal areas of the blank between said spaced clamps; and means for lpressing the lobes against one face of the blank to stretch the marginal areas of the blank between said clamps.

2. Apparatus, according to claim 1, in which the mould has a lobe arranged for engagement against the marginal portions of the blank along one lateral edge thereof between the toe portion and the waist portion, and another lobe for engagement against the marginal portion of the blank along the other lateral edge of the blank between the toe portion and the waist portion.

3. Apparatus according to claim 1 in which the mould has three lobes arranged for engagement against the blank, one between the toe portion and waist portion of one side, the second between the toe portion and waist portion at the other side, and the third along the region between the Waist portions.

4. Apparatus, according to claim 1, in which the lobes decrease in height from their outer edges to their inner edges, respectively, so as to leave the center portion of the blank relatively unstretched.

5. The invention, as defined in claim 3, in which the lobes decrease in height from their outer edges to their inner edges, respectively, so as to leave the center portion of the blank relatively unstretched.

o. Apparatus, according to claim l, in Which said lobes constitute the sole means for preshaping the blank.

7. A mould for preshaping an upper forepart blank comprising a body having three lobes in approximately trefoil formation, the outer edges of lobes having predetermined heights, each lobe decreasing in height toward the center of the body.

8. A mould, as delined in claim 7, which also includes means for manipulating the mould into position against one face of a blank with the outer edges of the lobes adjacent marginal portions of the blank.

9. Apparatus for preshaping a substantially triangular forepart blank comprising a plurality of clamps for e11- gaging the marginal portions of the blan'k, one clamp being positioned at each apex of the triangular blank to support the blank in substantially at stretched-out condition; a mould having a plurality of lobes, each positioned to engage a marginal portion of the blank between adjacent clamps; and means for pressing the mould against the stretched-out blank to preform the same.

References Cited by the Examiner UNTTED STATES PATENTS PATRICK D. LAWSON, Primary Examiner.

Claims (1)

1. APPARATUS FOR PRESHAPING AN UPPER FOREPART BLANK COMPRISING SPACED CLAMPS FOR ENGAGING THE BLANK ADJACENT ITS TOE AND WAIST MARGINAL AREAS AND POSITIONED TO SUPPORT THE BLANK IN A TAUT SUBSTANTIALLY FLAT CONDITION; A MOULD HAVING A PLURALITY OF LOBES POSITIONED TO ENGAGE SELECTED MARGINAL AREAS OF THE BLANK BETWEEN SAID SPACED CLAMPS; AND MEANS FOR PRESSING THE LOBES AGAINST ONE FACE OF THE BLANK TO STRETCH THE MARGINAL AREAS OF THE BLANK BETWEEN SAID CLAMPS.

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