US2216204A - Process of making insoles - Google Patents

Description

' Oct. 1. 1940. H. s. LUMBARD PROCESS OF MAKING INSOLES Filed Feb. 3, 1940 2 Sheets-Sheet 1 Oct. 1, 1940. G LUMBARD 2,216,204

PROCES OF MAKING INSO LES Filed Feb. :5, 1940 2 Sheets-Sheet 2 Patented Oct. 1, 1940 UNITED STATES PATENT OFFICE 2,216,204 raocsss or MAKING msoLEs I as... G. Lumbar-d, Auburn, Maine Application February 3, 1940, Serial No. 317,145

4 Claims. (Cl. 175-146) My invention relates to shoemaking and consists in a novel process for making insoles of ex traordinary flexibility.

Since the best shoe is the one which least 5 makes its presence known to the wearer, it fol lows that the sole structure must be so designed and assembled that it will follow without resistance the movements of the wearer's foot. Combined with this requirement of flexibility is the fact that the ideal shoe is one having suiilcient thickness of sole structure to act as a cushion so that the wearer cannot feel pebbles I and other irregular objects through the sole.

It will be apparent that these factors tend to work against one another, that is to say a sole structure which'is suiflciently'flexible is generally so thin that the wearer can feel objects through the shoe.

An additional problem to be considered arises irom the increased resistance encountered when two flexible members are secured together in face to face contact. If a thin flexible outsole is secured to a thin flexible insole, the resultin sole structure is relatively inflexible because the insole binds against the outsole when the latter is flexed and opposes effective resistance to the action of the outsole. The most important object of my invention is to provide a novel process for rendering an insole not only flexible per se but also capable of being combined with an outsole without offering any resistance to the action of the latter, with. the result that the flexibility of the combined 'sole structure may be measured by the flexibility of the outsole alon. W In my co-pending application Ser. No. 240,987

I have claimed my improved insole in combination with a shoe. In my Patent No. 2,181,787 I have claimed the method of making insoles of this character which comprises providing an intil sole blank of nearly" normal outline and thereafter elongating it by slashing it in a particular manner. The present application relates to a process for ,making insoles wherein the operations are initiated on a strip of insole material and at characterized by the important steps of stretching and releasing the slashed strip before insole blanks are cut .out.

The essence of my invention lies in the fact that an insole which will meet the requirements above discussed can only be produced if the slashing penetrates the entire thickness of the blank and also intersects the edges of the finished sole. In view of the fact that the toe, heel, and shank portions of a shoe should be relatively stiff as compared with that portion lying in-advance I o! the shank and behind the tip line, my novel process can advantageously be applied to insole material of the type disclosed in U. S. Patents Nos. 2,065,405, Sewall and 2,098,502, Leh'ner. These patents disclose sheet insole material 5 characterized by the provision of a relativelyflexible central portion and relatively ,stiflf and inflexible side bands; insoles or midsoles may be cut from such material in such a way that the toe and heel lie in the stiff side bands, whereas 10 the central portion of the insole lies in the flexible central strip or band. My invention may be characterized as an improvement upon the processes and insoles disclosed in these two patents- In one aspect the process of my invention is 15 characterized by the step of providing a strip of. insole material with a plurality of rows of closely spaced, through-and-through slashes. The slashed strip is then stretched at right angles to the direction of the slashes to expand the area 20 of the strip by opening the slashes. The stretching operation is not violent; it may effectively be done by hand; forexample, by grasping one edge of the strip in one hand and 'rubbing the other hand across the strip under some 25' pressure. It will be found that the slashes do not return to their initial condition when the stretching tension is released but assume a permanent intermediate open position. As a result of the slashing and stretching operations, the 30 strip will be found to be considerably wider than before these operations were undertaken. The longitudinal edges of the slashed strip are beveled, preferably before the slashing is done. The next step in the process is to cement solid 36 strips to the beveled edges of the slashed strip so that the latter is then provided with relatively stiff side bands of solid insole material. From the composite sheet thus formed insoles may be died out with their'toe and heel portions in the 40 stiff side bands and their niidportions in the slashed flexible strip.

It will be evident that the operation of attaching the side bands to the central strip may be efiected either before or after the slashing, stretching, and releasing operations. That is to say, a sheet of insole material may be made up of a relatively flexible central strip cemented at its longitudinal edges to side bands of relatively stiif material, the central strip being slightly narrower than ultimately desired. The slashing operation'may then be carried out only on the cen-' tral strip, whereupon the entire sheet is stretched to open the slashes in .the central strip and thereafter released. The total width of the sheet will be increased by reason'of the permanent expansion of the slashed central strip. Furthermore the operations may be carried out on a single broad sheet of insole material, a central portion of the uniform sheet being slashed, stretched, and released in accordance with my invention, the marginal portions being untreated and left in their original condition. The Sewall and Lehner patents disclose the step of slashing the central portion of a sheet of insole material, but they do not disclose slashingof the type which will permit permanent expansion of the central portion or which acts in such a way that upon stretching and releasing the sheet, the central portion is left in a permanent expanded condition with the slashes in an intermediate open position. When the slashing is carried out according to my invention, the stretching opens sheets.

the sheet is released, the slashes do not assume their initial condition but remain partly open, in which state their edges are freely movable and do not bind upon one another. It should be noted that the permanent expansion of the central portion of the sheet results in a saving of material, since the central strip may be initially somewhat narrower than will be ultimately required, the difference being made up by the slashing and stretching operations.

Insoles manufactured according to the process described in the foregoing paragraphs display an extraordinarilyhigh degree of flexibility when incorporated in a shoe, since the edges of the slashes have been separated by the stretching operation with the result that they are free to go and come as the shoe is flexed, thus providing no resistance or limit to the flexibility of the outsole. Broadly speaking, shoes manufactured with insoles of this type can be rated as to flexibility by the flexibility of the outsole, since the resistance of the insole is negligible.

Superior cushion insoles may be manufactured byflrst making a slashed insole blank according to the process described above, and then bonding the'blank to a cushion having the shape of an insole and cut out of resilient cushioning ma terial, such as a composition of ground cork and rubber. An important saving of material may be effected by cutting the insole blank a half size smaller than is required, cutting a cork cushion to the full size rquired and then slightly stretching the slashed blank as it is being bonded to the cork cushion, whereby the slashed blank will be expanded one-half a size. It will be ap arent that this final stretching of the slashe insole does not result in noticeable distortion, because the total length of the insole is only increased Vg".

It will be apparent that I first save material when I stretch the slashed strip, and then if a cushion insole is being made, I may effect a further saving in material by cutting the slashed blank V shorter than is required and stretching it to full size as it is bonded to the ply of cushion material.

It is also possible to make cushion insoles by bonding to a sheet of cushioning material a sheet of insole material which has had a portion thereof slashed, stretched, and released, and thereafter cutting out cushion insoles from the united The sheet with theslashed portion may be again stretched as it is secured to the cushion sheet in order to open the slashes further. However, this process is more expensive than cutting out separate insole blanks from the ion material is not necessarily co-extensive in' areawith the area of, the insole ormidsole to which it is secured. The several objects and features of my inven- ;tion will be readily understood and appreciated from the following detailed description of several preferred ways in which it may be practiced, as illustrated in the accompanying drawings in which;

Fig. 1 is a view in perspective of a strip of insole material slashed according to my invention,

Figs. 2, 3, and 4 are views in perspective of the slashed and stretched strip and the stiff side bands,

Fig. 5 is a view in perspective showing an insole cut from the combined strip and side bands, Fig. 6 is a view in perspective of a complete insole,

Fig.7 is a view in perspective of a cushion for an insole,

Figs. 8 and 9 are views in cross section illustrating the combining of an insole with a cushion,

Fig. 10 is a view in perspective of a fragment of a slashed strip under stretching tension,

Fig. 11 is a view in cross section of an insole embodying a thin tender layer.

In carrying out the process of my invention according to a preferred sequence of steps, I first prepare a strip ID of fibrous insole material with bevelled edges, as shown in Fig. 1, which material may consist of fibre board, paper stock, leather, or any of the materials suitable for making insoles ,The strip I0 is then provided with a number of rows of relatively short, spaced slashes or cuts I! all of which penetrate the entire thickness of the material. The slashing is carried out to intersect the end edges of the strip I0. By grasping one side of the strip 10 and rubbing a hand across it with some pressure in a direction normal to the direction of the slashes, I stretch the strip ill laterally, thus increasing its area by reason of the fact that the slashes open up under tension as shown in Fig 10. This action cannot be obtained unless th slashes penetrate the entire thickness of the strip l0 and also intersect the edges thereof. 4 i I When the stretching tension on the strip I0 is released, the slashes contract and assume an intermediate open position as illustrated inFig.

3. The widthof the slashing in Figs. 3 and 10 is somewhat exaggerated for purposes of illustration. It will be apparent, however, that the edges of the slashesare permanently separated and are therefore freely movable relative to one another.

The bevelled longitudinal edges of the slashed and stretched strip III are cemented to correspondingly bevelled edges of a pairof bands I 4 and I6 of relatively stiff material such as fibre board so that a sheet is formed comprising the slashed and stretched central strip 10 and the stiff side bands I4 and IS. The dimensions of the strip and side bands are dependent upon the desired location in a finished insole of flexible and stiff areas.

After the composite sheet has been formed by the attachment of the side bands l4 and IS, insoles may be cut therefrom. In'Flg. 5 I have shown an insole l8 cut from the sheet so that it has a flexible forepart combined with a stiff toe 22 cut from the material of the band l4 and a stiff shank and heel 20 cut from the band IS. The insole l8 may be used in the manufacture of a shoe according to any of the conventional methods of shoemaking. It will be apparent that the sequence of operations may be varied provided the slashing and stretching precede the cutting out of the insole. For example, the strip lll'may be secured to the side bands [4 and it before the slashing is done. Furthermore it is possible to slash the central portion of a'sheet of homogeneous material wherein the marginal portions are relatively stiffer than the central area merely because they are not slashed and notbecause their composition is diflerent.

My invention is particularly useful in the manufacture of cushion insoles, and in this connection I provide a cushion 24 cut to the shape of an insole and made of ground cork and rubber or other suitable cushioning material. To effect a saving in material I may cut the insole H! a half size smaller than the cushion 24 and stretch it to the size of the cushion while cementing it thereto. In Fig. 8 I have illustrated the insole l8 superposed on the cushion 24, the insole being shorter than the cushion. In Fig. 9 the insole It has been stretched to coincide with the area of the cushion 24. The slashes in the latter case are, as shown, expanded more than in Fig. 8. Therefore I may save half a size of insole material in'each cushion insole. Obviously I may omit the second stretching step and cut the insole full size and bond it to the cushion without stretch-.

, ing it again. The stretching operation which is fects a saving in insole material. It should be I done to increase the insole a half size is not sufficient to distort the insole appreciably. How- A sheet of cushioning material may be bonded by cement to a sheet comprising a slashed and stretched central strip with stiff side bands and flexible cushion insoles cuttherefrom. However, it is more eflicient to cut the blanks separately and so avoid waste of cushion material.

When a cushion is not desired and the cement side lasting process is to be used in the manufacture of the shoe, I prefer to employ a layer 26 of thin, tender paper or cloth which is only stiff enough to pass through a latex coating machine without curling. After the insole 18 has been cut out it is laminated with the layer 26 which has previously been coated with latex. The purpose of the layer is to prevent the cement used in lasting from coming through the slashes l2 and reaching the last bottom. Otherwise the-insole It would be cemented to the bottom of the last, and last pulling would be difllcult if not impossible. In the shoe the material of the layer 26 will break apart or give way in wear where it is bonded to the slashed portion of the insole l8 and thus have practically no stiffening efiect. The layer 26 will not lump up or come adrift in a shoe because it is cemented to the insole l8 and held in place between the insole and outsole. Furthermore the layer 26 may be cut to full size and the insole l8 cut down half a size and then elongated to, full size in the process of laminating the two together as shown in Fig. 11. This efpointed out that the layer 26 will act to stiifen an insole unless the insole is slashed according to my invention. Also use of layer 26 permits the employment of thinner cloth for the insole proper.

I am aware that in British PatentNo. 979 of 1888 and in GermanPatent No. 343,037 of 1920 'is disclosed a process of making soles which comprises cutting out a blank of indeterminate form, slashing the-blank, stretching the slashed blank to distort it into the shape of a sole, and finally filling the slashes with india rubber or other My novel process is an improvement upon the aforementioned process because the insole blank, in my process, is not cut out until after' the stretching operation has been accomplished. Furthermore it is important that the holes formed by slashing the sheet Ill and stretching it be left as free spaces in the body of the insole. The edges of the slashes must be free to move as the sole is flexed in wear, and to press a filler into the slashes would immobilize the edges thereof and greatly diminish the flexibility of the insole.

Although a piece of material is permanently expanded somewhat when it is slashed with a bevelled knife as contemplated herein, the permanent expansion resulting from the stretching operation is greater and has important advan-' tages of flexibility and material saving.

.My invention is not limited tothe manufacture of full size insoles but is well adapted for the manufacture of forepart insoles, midsoles, and insoles having flexible portions in theshank or toe as well as in the forepart. The term insole" as used in the appended claims is specifically. intended to include the variations mentioned above Having thus described my invention what I claim 'as'new and desire to secure by Letters Patent of the United States is:

1. A process for making insoles which comprises providing a strip of fibrous material with a plurality of rows of short spaced through-andthrough slashes some of which intersect the edges of the strip, stretching the slashed strip to open the slashes, releasing said strip to allow the slashes to as ume an intermediate open position, securing so side bands to the longitudinal edges of said strip, and cutting out insoles from the composite sheet thus formed so that the heel and toe portions thereof lie within the solid side band and the central portionlies. within the slashed strip.

2. A process of making an insole, which comprises providing a strip of material with a plurality of rows'pof short, spaced, through-andthrough slashes someof which intersect the ends of the strip, stretchingthe strip laterally to ex pancl the strip and open the slashes, releasing the strip to allow the slashes to assume a permanent partially open position, securing sidebandsof relatively stiff material to the strip, cutting out a short insole from the sheet thus formed so that a portion of the insole includes material cut from the slashed strip, providing a full size cushion, stretching the insole to full size, and then bonding the insole to said cushion.

3. A process of making an insole, which comprises providing a strip of material with a plurality of rows of short, spaced, through-andthrough slashes some of which intersect the ends of the strip, stretching the strip laterally to expand the strip and open the slashes, releasing the strip to allow the slashes to assume an intermediate open position, securing side bands of relatively stiff material to the strip, cutting out an insole from the sheet thus formed so that a portion of the insole includes material cut from the slashed strip, providing a cushion, and bonding' the insole to the cushion.

4. A process of making an insole which comprises providing a strip of material with a plurality of rows of short, spaced, through-andthrough slashes, stretching the strip laterally to expand the strip and open the slashes, releasing the strip to allow the slashes to assume a permanent open position, securing a side band of relatively stiifer material to the strip, and cutting out an insole from the combined strip and band so that a portion of the insole includes material cut from the slashed strip.

HENRY G. LUMBARD.

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