US2973530A - Method of manufacturing shoes - Google Patents

Method of manufacturing shoes Download PDF

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Publication number
US2973530A
US2973530A US810807A US81080759A US2973530A US 2973530 A US2973530 A US 2973530A US 810807 A US810807 A US 810807A US 81080759 A US81080759 A US 81080759A US 2973530 A US2973530 A US 2973530A
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United States
Prior art keywords
leather
moisture
shoes
uppers
heat
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US810807A
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English (en)
Inventor
Morton S Bromfield
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Individual
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Individual
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Filing date
Publication date
Priority to GB24225/58A priority Critical patent/GB857012A/en
Application filed by Individual filed Critical Individual
Priority to US810807A priority patent/US2973530A/en
Priority to GB31973/60A priority patent/GB975936A/en
Priority to GB31596/59A priority patent/GB933183A/en
Priority to CH382460A priority patent/CH391511A/de
Application granted granted Critical
Publication of US2973530A publication Critical patent/US2973530A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A43—FOOTWEAR
    • A43D—MACHINES, TOOLS, EQUIPMENT OR METHODS FOR MANUFACTURING OR REPAIRING FOOTWEAR
    • A43D95/00—Shoe-finishing machines
    • A43D95/12—Devices for conditioning, tempering, or moistening
    • A—HUMAN NECESSITIES
    • A43—FOOTWEAR
    • A43D—MACHINES, TOOLS, EQUIPMENT OR METHODS FOR MANUFACTURING OR REPAIRING FOOTWEAR
    • A43D11/00—Machines for preliminary treatment or assembling of upper-parts, counters, or insoles on their lasts preparatory to the pulling-over or lasting operations; Applying or removing protective coverings
    • A43D11/14—Devices for treating shoe parts, e.g. stiffeners, with steam or liquid

Definitions

  • the most important object of my invention is to improve the efliciency of shoemaking.
  • Another object of my invention is to improve the quality of shoes.
  • the most important feature of my invention resides in a combination of process steps comprising moistening only the surface zones of upper stock, such as leather, lasting the shoe shortly after the moistening step, while the stock is in a condition of maximum flexibility and prior to permeation of the stock by moisture, and then quickly removing the moisture from the surface zones, thereby simultaneously causing maximum shrinkage of th; sftock upon the last and also achieving optimum stress re re
  • moistening only the surface zones of upper stock, such as leather, lasting the shoe shortly after the moistening step while the stock is in a condition of maximum flexibility and prior to permeation of the stock by moisture, and then quickly removing the moisture from the surface zones, thereby simultaneously causing maximum shrinkage of th; sftock upon the last and also achieving optimum stress re re
  • Lasting is more easily accomplished, not only because the upper stock is at maximum flexibility but also because uppers may be sequentially mulled continuously and uniformly, thus minimizing variations in the force and stroke required of the lasting instrumentalities.
  • the moisture content of the several uppers within a single lot is not uniform. Moreover, the moisture content throughout each upper is not uniform because of the nesting characteristics of the uppers. While some parts of each upper are in contact with parts of adjacent uppers and are thus insulated from the heat and moisture of the miller, other parts of the uppers are spaced from the adjacent uppers and exposed to the muller atmosphere. The lack of uniformity is further aggravated by the fact that some case lots remain in the muller for but a few hours, while others remain in the muller for twenty-four hours or more, and when the uppers are lasted, the moisture in some will have dispersed throughout the material while in others a moisture gradient may yet exist. In an effort to compensate for the nonuniform moisture conditions many lasting operators employ steam boxes disposed beside their benches to remull a part or all of each upper handled by them.
  • the water droplets not only mar certain leather finishes but also exaggerate the stretch characteristics of different portions of the skin.
  • the soft fleshy areas of the skin which normally are more stretchable than the bony areas, absorb moisture more rapidly.
  • the stretch differential of these portions is exaggerated.
  • Superheated steam mullers have not been adopted by the industry because of the necessity for close time control to minimize the shrinkage and shrivelling effects.
  • Another feature of my invention resides in the utilization of the drying heat to help develop a heat reservoir in the overlasted margin of the upper before sole attaching cement is applied to the margin.
  • the established heat reservoir co-operates with additional heat applied to the exposed surface of the cement to condition the cement for receiving the sole.
  • Figure l is'a graph illustrating the effects of moisture dispersion on the stiffness of leather
  • Figure 2 is a cross sectional view of a piece of leather
  • Figure 3 is a graph illustrating the effects of rapid drying on total shrinkage of leather --with workable amounts of moisture present;
  • Figure 4 is a diagrammaticview in perspective of an assembly line which may be used to practice the method of my invention.
  • FigureS is agraph showing the moisture content and relative flexibility of the upper throughout the manufacturing cycle practiced on the line of Figure 4.
  • the graph of Figure 1 illustrates the effect of moisture upon leather described above, when the total moisture content of the leather remains constant. The time values minutes after moisture is applied to its surface. It will be "appreciated that if the total moisture content of the leather uppers remains approximately constant, maximum workability of the leather is available to lasting operators only iftheir operations are performed before the moisture intro- ,duced by mulling disperses throughout the leather. The graph of Figure 1 suggests that the lasting operations :Should'be performed within approximately twenty-five minutes after-the initial application of moisture to the surface of the leather.
  • the grain layer rup- The mucoid layer 14 is primarily a bonding film between the grain and the corium and is a negligible factor when considering the structural properties of leather. While the corium has greater tensile strength than the grain, the usual splitting of a hide into at least two separate skins results in splaying open the corium fiber bundles, much likecutting the end of a rope crudely,
  • the grain side of asplit skin used unlined'or unfinished as a shoe upper has its workability limited by the grain layer both because'of its inherent physical properties and because it is "the outer fiber area in bending beam theory. As the grain limits the workability of leather, the application of "moisture to that area enhances the bendability and stretchability of the material.
  • the tensile strength and elongation properties of leather finishes vary widely but most are thermoplastic.
  • the efiects of heat upon mulling of leather should be considered. Heat lowers the viscosity and surface tension of liquid and enables it to more readily penetrate the surface. Not only does the heat quicken the rate at which the moisture is absorbed into the surface areas of the leather but it also acts upon the thermoplastic fat liquors in leather to soften them. Thus, heat is an important adjunct of moisture in improving the workability and stretchability of leather.
  • Dispersion may occur both into the atmosphere and into the leather. Dispersion into either avenue adversely affects workability but dispersion into the leather alone markedly limits the drying rate and the shrinkage possible. Greater shrinkage of leather occurs in response to rapid drying when the moisture content and concentration in the leather initially is relatively high. The combination of heat and adequate moisture allows for maximum fiber movement.
  • the combination of moisture and heat also performsa stress relieving action inleather.
  • suflicient moisture present in the leather to lubricate the least ductile grainfibers heat is able to reach the moisture and soften the fat liquors and the relatively stiff grain fibers within and beyond the moisture laden area to allow maximum
  • the heat causes the fat liquors and fibers to yield to the accelerated shrinkage induced by rapid moisture removal.
  • thestress relieving effects 'a shrinkage in the slack areas of the upper and a relief of tension in the taut areas for an intimate l'astfit. 'If the stresses of the leather are not relieved in thismanner before the last is pulled, they will cause flattening of the lines of the upper after the last is pulled.
  • the assembly line shown in Figure 4 is provided to carry the various shoe parts to the several operators disposed about it and also serves to carry the shoe parts through a muller and several heaters whose functions are described in detail below.
  • the conveyor 16 travels an endless course about the several operators stationed adjacent to it.
  • An operator 18 positioned intermediate the ends of the run 20 of the conveyor 18 takes stitched uppers one at a time from a rack 22 and places them in a muller 24 disposed above the conveyor.
  • a conveyor (not shown) travels through the muller 24 and transports the uppers to an operator 26 stationed at the discharge end of the muller.
  • the warm moist atmosphere of the muller may be maintained by bubbling steam through a water filled trough.
  • the actual manner in which the desired atmospheric conditions are created is not part of this invention and is not shown.
  • the outer surfaces of the upper are exposed to this moist atmosphere and absorb water.
  • Uppers when placed in the muller have a moisture content of approximately eleven percent by weight and upon leaving the muller the moisture content of the surface zones leather is approximately 18 to 22%.
  • moisture content and flexibility are plotted against time and this increase in the moisture content is illustrated. Approximately three minutes are required for the uppers to travel through the muller, and maximum moisture content is shown to occur in Figure 3 three minutes after the beginning of the manufacturing cycle. It will also be noted in Figure 5 that when the upper leaves the muller it has approximately maximum relative flexibility.
  • the temperature of the muller atmosphere is main tained at approximately 140 F.180 F., a range close to steam temperature and well above normal mulling temperatures which are usually below the melting temperature of leather fibrils, 130 F.
  • the relatively high temperature of the muller gives it a capacity many times greater than conventional mullers, and the muller is able to provide accelerated moisture absorption comparable to that provided by steam but without the uncontrolled shrinkage that can result.
  • the additional heat of vaporization that would pass from the steam into the leather with condensation would unnecessarily raise the leather temperature and reduce the leather-atmosphere temperature differential so important in mulling rate.
  • the operator 18 places the uppers on the conveyor in the muller 24, he also places an outsole and a matching counter on the conveyor 16. As the upper reaches the end of the muller and is drop-delivered to the operator 26, the matching outsole and counter arrive on the conveyor 16 at his station. After inserting the counter,
  • the operator 26 assembles the upper on the last and then surface zones to evaporate.
  • Thepull-over operator 28 ideally pulls the shoes in pairs on conventional machinery and then places the lasts on the transport posts 30 carried by the conveyor 16.
  • the conveyor 16 carries the shoes to the side lasters 32 and 34, who side last the left and right shoes respectively, and thereafter replace them on the transport posts 30.
  • the conveyor transports the shoes to the forepart laster 36 who wipes in and secures the forepart of each upper and places the shoes on a secondary conveyor (not shown) which'carries them over a perforated plate which emits steam.
  • a secondary conveyor (not shown) which'carries them over a perforated plate which emits steam.
  • the secondary conveyor the shoes are disposed in an upright position and the steam is directed to the underside of the leather through the downwardly extending rabbit ears which are formed between the pull-over tacks. This application of steam softens the box toe of the upper which isnormally thermoplastic.
  • the secondary conveyor carries the shoes to the bedlasters 38 and 40 who last the toes of the shoes and replace them on the transport posts carried by the conveyor 16.
  • the conveyor 16 next brings the shoes to the heel seat laster 42 who removes the insole tacks and nails the heel seat in place on each shoe.
  • a heater 44 in the form of a shroud sur rounding the conveyor is provided for this purpose.
  • the heater 44 may be provided with any form of heat source such as infrared lamps or quartz heaters directing heat to the exposed surface of the leather. During the approximately one minute period required for the uppers to travel through the heater 44, the moisture content of the surface or grain of the leather drops from approxi mately 16 to 20%, to 11%.
  • leather that is,'with more moisture'injthe interior'zone than in the grains
  • leather wet throughout dries through a series of pulses of moisture transfer; surface evaporation, and shrinkage reversal vorswelling. ;As a result, the shoemaker cannot derive the maximum shrinkage which is obtained by rapid removal of high moisture concentration at the grain area.
  • the high concentration of moisture throughout the cross section'fights Furtherrnore if the drying heat levaporates the moisture at the surface zone vfaster 'thanthe interior can release moisture to replace that which has evaporated, overheating, embrittlement, case "hardening, and scorching may result.
  • the muller applies moisture to the surface zones of the upper where it isrequired for maximum workability.
  • The'lasti'ng operations are performed immediately after mulling when the relative stiifness of the leather is .at a minimum.
  • i moisture is removed from the leather by thelheater before it has an opportunity to pervade the center zone of the upper, that is, whilethe moisture gradient is substantially at a maximum, and thus maximum shrinkage and stress relieving action are acquired.
  • y 1 p The three minute mulling period, the eight 'm inute lasting period, and the one minute force drying period are particularly suitable. for uppers made of leather splits of a weight commonly used in womens shoes. Just as in the relative stiffness graphvof Figure -'l, with heavier stock the time required tolast as well as the times requiredto deposit adequate moisturein the surface areas and thereafter withdraw it will vary by some determinable scale'factor. 7
  • the operator 52 may also perform necessary odd crowning operations.- After completing his work, the operator 52 replaces the shoe on the transport post of the conveyor and the shoe is .carriedto operator 54 who pounds the overlasted margin of the upper and roughs it in preparation for the application of a 'co atingof; cement. lfrhigh heel shoes are'in process, an operator 55 is employed to place the shauk on each shoe.--'If flattiesare being manufactured, the. operator .55 is unneces-;
  • the shoes are placed in the rack 76 by the sole layer approximately thirty seconds after they reach his station on the conveyor, to complete the twentyin the manufacture of shoes to leave-uppers on the last I for several hours or more after the shoemaking operations are completed.
  • the shoes are left on the-lasts for several days .afterassembling is completed.
  • All shoe manufacturers have recognized that only by sacrificing shoe quality can the lasts be pulled from the shoes in less than several days.
  • thelasts maybe pulled almost immediately after the force drying period. and the quality of the shoesis the equivalentof those left on the lasts a week or more after being manufactured in accordance standard practices.
  • the work in process maybe reduced to approximately 168 shoes, about 3% of the number of shoes in
  • the flash drying permits the lasts to be process customarily necessary to achieve a rate of production comparable to that realized from the practice of my invention.
  • the controlled shrinkage of the upper allows the lasting operators to ut lize the full lasting allowance before premature shrinkage takes place.
  • the controlled shrinkage also allows for the tighter cutting of patterns which may result in approximately a 3 saving of leather.
  • the intimacy and durability of the fit which are the result of maximum leather shrinkage and stress relieving action provide the manufacturer with an improved product. Furthermore, the original last shape is maintained and the finish of the leather is preserved.
  • the uniform and controlled mulling also enable the lasting machine tensions to be properly set for a given amount of fight in leather uppers to minimize over or under pulling of variably conditioned uppers. Moreover, the uniformity and control of the mulling enable shoe manufacturers to employ certain automatic lasting equipment which is available but which has not been used in the past, due to the relatively wide variations in the tolerances hitherto encountered in the workability of uppers in the lasting process.
  • a method of Shoemaking including the steps in sequence of subjecting an outer surface of a leather upper to a water treatment to introduce into an outer surface zone only sufiicient water to increase the flexibility of said surface zone, lasting said upper before said Water can pervade the center zone of the upper, and subjecting the lasted shoe to heat to remove said water from said surface zone before it pervades the center zone of said upper.

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  • Treatment And Processing Of Natural Fur Or Leather (AREA)
  • Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
US810807A 1958-07-28 1959-05-04 Method of manufacturing shoes Expired - Lifetime US2973530A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB24225/58A GB857012A (en) 1958-07-28 1958-07-28 Improvements in and relating to the manufacture of shoes
US810807A US2973530A (en) 1959-05-04 1959-05-04 Method of manufacturing shoes
GB31973/60A GB975936A (en) 1958-07-28 1959-09-16 Improvements in and relating to conveyor systems for shoe making assembling operations
GB31596/59A GB933183A (en) 1959-05-04 1959-09-16 Method of manufacturing shoes
CH382460A CH391511A (de) 1959-05-04 1960-04-05 Verfahren zur Fabrikation von Schuhen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US810807A US2973530A (en) 1959-05-04 1959-05-04 Method of manufacturing shoes

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US2973530A true US2973530A (en) 1961-03-07

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US810807A Expired - Lifetime US2973530A (en) 1958-07-28 1959-05-04 Method of manufacturing shoes

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CH (1) CH391511A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161898A (en) * 1961-04-28 1964-12-22 Morton S Bromfield Shoe making apparatus
US3176333A (en) * 1963-09-17 1965-04-06 United Shoe Machinery Corp Methods of conditioning shoe uppers
US3217345A (en) * 1961-08-18 1965-11-16 B W Footwear Company Method of making shoes
US3220033A (en) * 1962-03-06 1965-11-30 Morton S Bromfield Apparatus for treating shoe uppers
US3220036A (en) * 1962-03-06 1965-11-30 Morton S Bromfield Process for mulling shoe uppers
US3237227A (en) * 1964-04-10 1966-03-01 Formulast Corp Directionally shrinking lasted shoe uppers
US3374496A (en) * 1965-11-03 1968-03-26 Stubbings Robert Method of lasting leather uppers
US20130299492A1 (en) * 2012-05-10 2013-11-14 Preco, Inc. Odor reduction in laser processed material with curl reduction

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1825191A (en) * 1931-03-20 1931-09-29 Henry G Lumbard Method of tempering shoe uppers
US1919464A (en) * 1931-09-24 1933-07-25 Claude H Daniels Method of manufacturing boots or shoes
US2294481A (en) * 1940-07-29 1942-09-01 United Shoe Machinery Corp Method and apparatus for use in shoemaking employing heat
US2633583A (en) * 1950-03-16 1953-04-07 United Shoe Machinery Corp Shoe conditioning apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1825191A (en) * 1931-03-20 1931-09-29 Henry G Lumbard Method of tempering shoe uppers
US1919464A (en) * 1931-09-24 1933-07-25 Claude H Daniels Method of manufacturing boots or shoes
US2294481A (en) * 1940-07-29 1942-09-01 United Shoe Machinery Corp Method and apparatus for use in shoemaking employing heat
US2633583A (en) * 1950-03-16 1953-04-07 United Shoe Machinery Corp Shoe conditioning apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161898A (en) * 1961-04-28 1964-12-22 Morton S Bromfield Shoe making apparatus
US3217345A (en) * 1961-08-18 1965-11-16 B W Footwear Company Method of making shoes
US3220033A (en) * 1962-03-06 1965-11-30 Morton S Bromfield Apparatus for treating shoe uppers
US3220036A (en) * 1962-03-06 1965-11-30 Morton S Bromfield Process for mulling shoe uppers
US3176333A (en) * 1963-09-17 1965-04-06 United Shoe Machinery Corp Methods of conditioning shoe uppers
US3237227A (en) * 1964-04-10 1966-03-01 Formulast Corp Directionally shrinking lasted shoe uppers
US3374496A (en) * 1965-11-03 1968-03-26 Stubbings Robert Method of lasting leather uppers
US20130299492A1 (en) * 2012-05-10 2013-11-14 Preco, Inc. Odor reduction in laser processed material with curl reduction
US10179378B2 (en) * 2012-05-10 2019-01-15 Preco, Inc. Odor reduction in laser processed material with curl reduction

Also Published As

Publication number Publication date
CH391511A (de) 1965-04-30

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