US2520995A - Manufacture of shoes - Google Patents

Description

Sept 5-, 1950 J. J. BROPHY 2,520,995

MANUFACTURE OF SHOES Filed Dec. 22, 1948 2 Sheets-Sheet 1 Sept. 5, 1950 J. J. BROPHY 2,520,995

MANUFACTURE OF SHOES Filed Dec. 22, 1948 2 Sheets-Sheet 2 Patented Sept. 5, 1950 E D S TAT ES PAT ENT ()"FF l C E MANUFACTURE OF SHOES John J.- Brophy, Salem, Mass., assignor to United Shoe Machinery Corporation, Fle'mington', N. J'., a; corporation of New Jersey Application-December 22, 1948, Serial No. 66,607

Claims. I

Thisinvention relatesto the manufactureof shoes and particularly to an improvement in methods of making. shoes. However, in other aspects the invention contemplates a novel apparatus for use in practicing this improvement in methods of makingshoes, as well as a novel product which results therefrom.

In the manufacture of shoes, it is of great importance-that every tack, temporarily employed to, hold-the insole .on the last, be withdrawn or removed from the-insoleand last before an out- .sole .is applied, because thereafter a tack cannot be pulled out and the tack, left extending into the inside of the shoe, may only be partially remo.ved,.after the lastis pulled, by the time-consuming job of s ipping the point off fromthe insideof the shoe as close tothe insole as possible. Suchashoe is likely. to render but short .service. to the wearer before the remainder of .the tackwill work higher into the shoeand eventually penetrate the sock lining.

Heretofore, it. hasbeen necessary to withdraw each ofthe. insole positioning tacks individually, either by a hand toclor by atack pulling ma- .chindand, in spite ofv all practical precautions off the tack, leaving the embedded point diffi- ,cult todetect and extract until after the last has been pulled.

Another objectionable feature of the present manner .of removing tacks is that permanent damage. may be occasioned to the insole by the tack puller which, inorder to grasp and with- .draw a.d.eeply embedded tack, frequently has to .bite .deeply into the texture of the insole, thus producinglarge gouged out areas which weaken the ultimate shoe construction and necessitate sebsequent doctoring with bottom filler in .order.,to insure. an even treading surface for the foot.

It is-an, object of this invention to provide an improvementin methods of making shoes which will result in. theelimination of the difficulties .Whichhave just been mentioned. More specifically,- thisv improvementcomprises temporarily securing an insole toa last-by means of fasten- .ings. which, after the upper. has been attachedto .the insole and, before the outsole is applied, may be easily and certainly removed without damaging the insole. For this purpose, and in accordancewith a-.-feat ure of the invention, the fastenings.for example tacks, ,are madeof read- 2. ily fusible material so that they may be easily removed by melting atrelatively low temperatures which will have no adverse effect on the insole itself. In the herein illustratedv embodiment of the invention, two different. types of fastening materials are suggested, namely, low melting point metals and plastics, the former of which may be melted by the action of inductionheating, while the latter may be melted by means of dielectric heating.

Another object of the invention. is to provide anovel apparatus for melting andremoving. fastenings of the kinds setforth above from the bottom of a shoe. For this purpose, there is. provided a table for supporting a shoe by engagement with itsbottom and having meansfor heat,- ing insole fastenings to melt them and cause them to drop out of theshoe bO-ttom. Preferably, means are also provided for imparting a vibratory movement to the table for the purpose of dislodging the melted fastenings and thus facilitatingtheir removal.

A still further object of the invention is to provide a novel product for use in the manufacture of shoes. Thus, invention will also be recognized in the novel intermediate product comprising a last having an insole secured thereto by means of readily fusible fastenings which maybe easily removed, after an upperhas been attached to the insole and before an outsol-e has been applied, bymelting at arelatively low temperature without damag t the insole.

These and other novel features and objects of the invention will be apparent from the accompanying drawings and hereinafter described and claimed.

Referring to the drawings,

Fig. 1 illustrates an insole temporarily tacked upon a last;

Fig. 2 shows a shoe, comprising an upper and insole assembled on a last, with the lasting margin of the upper permanently secured to the Fig. 0 shows a modified apparatus, partially brokenaway, for removing tacks in accordance with another mode of operation;

Fig. '7 is a sectional view of the apparatus of Fig. 6, taken along the line VIIVH and viewed in the direction of the arrows, to further illustrate features of the invention; and

Fig. 8 illustrates still another modified apparatus for carrying out the invention in accordance with a further mode of operation.

According to one aspect of the improvement in methods of making shoes, and as illustrated in the drawings, Figs. 1 through 5, an insole 20 is spotted and temporarily tacked in proper position upon a last 22 using the customary arrangement of tacks except that the tacks 24 employed are formed of a metallic alloy, such for example, as Rose or Woods Metal, characterized by a low melting point, a relatively high specific gravity and being capable of electrical conductivity. Then, after the usualopenations, such as upper assembling, pulling over, side, heel and toe lasting, have been performed to attach the lasted up- ,per 26 permanently to the insole, as by the staples 25, the temporary insole .fastening tacks 24 are removed by melting, the heat being generated throughout the tacks by high frequency electrical induction. 7

This operation may be accomplished by holding the shoe of Fig. 2 bottom down upon the novel tack removing apparatus as shown in Figs. 3 and '4, where for the sake of brevity, only so much of the apparatus as includes means for melting the tacks in the forepa-rt of the shoe has been illustrated; it is however to be understood that the tacks in the shank and heel portions may be simultaneously removed by similar melting means associated with the broken away portion of the apparatus and concentrically located with the respective tacks.

through the table, the resilient layer and the base r plate. The edges 29, 2c of this opening approximate the peripheral shape of a shoe bottom but are of a smaller dimension so that when a shoe is operatively pcsitioned above the opening the peripheral bottom margins of the shoe will extend over the edges 29 and be supported upon the upper surface of the table 28. Within this opening and slightly below the supporting surface of the table are a series of electrical induction heating coils 36 arranged in a predetermined pattern so that each coil may be in approximate concentric alinement with one of the tacks 24. As an aid to properly positioning the shoe to locate the tacks above the coils, the table 28 is shown provided with a plurality of edge guides 35. The coils may be joined in an electrical series as illustrated, having their terminal leads 32 and 3 connected to a suitable source of high-frequency alternating current, not shown. Preferably, the conductor material for these coilsis formed of a continuous tube so that a cooling medium, such as Water, may be circulated throughout the coils to prevent them from becoming so overheat-ed as to adversely affect the texture of shoe leather in close proximity thereto. 7

It will be seen that when the shoe is held bottom down upon the (work table the insole tacks will be directly exposed to the heating coils. When thus subjected to the high-frequency magnetic fields surrounding the coils the tacks are rapidly heated and become fluid in "a, very short time. Their melting speed, if desired, may be increased by the addition of a small amount of copper or iron to the constituent alloy of the tacks.

In order to assure that no residue is left in the apertures 31; formed in the insole and last by the tacks, Fig. 4, the entire shoe may be rapidly and vigorously vibrated during the melting out process. This may be accomplished by imparting reciprocal up and down movement to the work table 28 b the force of the rapidly rotating cam 40 striking against and elevating the under surface of the table, thereby upwardly distending the resilient layer 38. As the point of the cam moves downward the table, drawn by the resiliency of the layer 38 and the force of gravity, descends to a level where it is once more engaged and elebe shaken freely from out the holes 3'1, and to fall through the central openings of the coils 3t and down through the cutout portion of the except that the method of removingthe plastic tacks and the apparatus therefor is essentially different.

In the case of plastic tacks, they likewise may all be removed simultaneously by melting out, the heat being uniformly generated throughout the tacks by high frequency dielectric heating. After the shoe has been lasted as shown in Fig. 2, the subsequentmelting out operation isperformed by holding the shoe down upon an apparatus similar to that of Fig. 3exceptthat the electrical induction heating coils are not employed because the plastic tacks are non-conductors of electricity. Instead of the coils 36, the central cutout portion of the work table 23 may be provided either with a number of wav guide tubes of conventional construction, as illustrated in Figs. 6 and 7, or with an arrangement Of electrodes as shown in Fig. 8. h

' Referring to the apparatus of Figs. 6 and '7, the wave guide tubes 44. should each be centrally positioned beneath one of the plastic tacks 46 so 'as to direct its dielectric forces upwards into the tack. The electrical operating frequency for this apparatus will in each case be dependent upon the size, shape and composition of the tacks employed. The tubes 44 should be so selected as to obtain the minimum of reflection back into the tube, and as to provide the most directional and concentrated fields of dielectric forces into the tack. This directional concentration of the dielectricfields is an important factor for two reasons; first, if the area of the insole encompassed by the field isexcessive it may cause an arcing over to adjacent metallic objects such as the staples 25, and secondly, since any leather containing moisture may have a relatively high factor of dielectric loss, this area may be deleteriously affected by overheating, thus weakening the structure of the shoe.

It will be noted that in the illustrated tube arrangement, the waves are guided from a suitable common generating source not shown, through a branch tube 48 leading into the several outlet tubes M and lta, the latter tubes when extended being operatively positioned beneath the tacks in the shank and heel portion of the insole. These guide tubes beneath each tack have a downward opening 45 so that the residue from the melted tacks may drop down and pass out through the bottom of the tubes.

When using th dielectric melting means shown in Fig. 8, the electrodes 56 should be arranged in pairs beneath each tack and the faces of the electrodes in each pair should be so positioned as to produce a dielectric field which extends outward as far as the point of the tack. Here again it is important to restrict the area of insole leather strongly affected by the field because of the danger of scorching the leather and of arcing over onto metallic fastenings such as staples or tacks.

While the herein disclosed novel method of temporarily fastening a sole to the last has been exemplified in the drawings as employed in the manufacture of a cement type of shoe construction, it is to be clearly understood that the invention and claims thereto are equally applicable to all types of shoe constructions wherein a sole is attached to a last by fastenings which penetrate through the sole and into the last.

It is also to be understood that in the illustrations of the apparatuses for removing the tacks the specific electrical arrangements are only shown by way of example. Since the choice of the best electrical heating elements and their arrangement as to size, configuration, and position may vary according to the chemical, electrical and physical characteristics of the particular fastenings employed, and since this choice may be readily ascertained by one skilled in the arts of induction or dielectric heating, the scope of the present invention is not intended to be limited to the specific arrangements disclosed in the drawings.

The temperatures, which must necessarily be produced within the fastenings in order to efiect a complete melting thereof, will vary according to the material of which the particular fastening is composed. This invention contemplates the employment of such materials as will have a relatively low melting point, so that complete fusion will take place below 400 F.

Having thus described my 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 shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last with readily fusible fastening means, and, after an upper has been secured to the insole, removing the temporary fastening means by subjecting them to heat sufficient to cause them to melt out from the last and insole.

2. That improvement in methods of making shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last by means of readily fusible fastenings, and, after an upper has been secured to the iii 6 insole, removing said fastenings by subjecting them to a high frequency field until the internal heat thus produced throughout the fastenings causes them to melt out from the last and insole.

3. That improvement in methods of making shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last by means of readily fusible fastenings formed of an electrically conductive alloy, and, after an upper has been secured to the insole, removing fastenings by subjecting them to high frequency electro-magnetic fields until the internal heat thus produced throughout the fastenings causes them to melt out from the last and insole.

4. That improvement in methods of making shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last by means of fastenings formed of a readily fusible electrically conductive alloy, and, after an upper has been secured to the insole, removing said fastenings by subjecting them to high frequency induction heating until the internal heat thus produced throughout the fastenings causes them to melt out from the last and insole.

5. That improvement in methods of making shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last by means of fastenings formed of readily fusible dielectric plastic material, and, after an upper has been secured to the insole, removing said fastenings by subjecting them to high frequency electric fields until the internal heat thus produced throughout the fastenings causes them to melt out from the last and insole.

6. That improvement in methods of making shoes which comprises the steps of positioning an insole upon a last, temporarily securing said insole to the last by means of fastenings formed of a readily fusible material having a high dielectric loss, and, after an upper has been secured to the insole, removing said fastenings by subjecting them to high frequency dielectric heating until the internal heat thus produced throughout the fastenings causes them to melt out from the last and insole.

7. A step product for use in the manufacture of shoes comprising a last and a sole member secured to the bottom of the last by readily fusible fastenings.

8. A step product for use in the manufacture of shoes comprising a last and a sole member secured to the bottom of the last by readily fusible metallic fastenings.

9. A step product for use in the manufacture of shoes comprising a last and a sole member secured to the bottom of the last by readily fusible plastic fastenings.

10. A step product for use in the manufacture of shoes comprising a last and sole member secured thereto by fastening means which may thereafter be melted out by fusion at a temperature below 400 F.

JOHN J. BROPHY.

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

UNITED STATES PATENTS Number Name Date 1,790,19'1 Winkley Jan. 27, 1931 1,825,206 Rivas Sept. 29, 1931 2,383,992 Sherman Sept. 4, 1945 2.415.025 Grell et a1. Jan. 28, 1947

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