US3729843A

US3729843A - Soft-soled foorwear

Info

Publication number: US3729843A
Application number: US00146885A
Authority: US
Inventors: D Greenblatt; A Greenblatt
Original assignee: D Greenblatt; A Greenblatt
Current assignee: NEW AMERICAN SHOE COMPANY Inc
Priority date: 1971-05-26
Filing date: 1971-05-26
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

An article of footwear and method and apparatus for making the same are disclosed. The footwear article consists of a unitary upper and an integral one-piece bottom, substantially the same thickness as the upper and preferably formed of injected molded thermoplastic composition. The bottom is provided with an integral upwardly extending peripheral sidewall portion overlying and bonded to a lower portion of the upper. The sidewall portion has an outer surface merging substantially continuously in rounded manner into the tread surface of the bottom. The mold assembly consists of a one-piece cavity mold having an inwardly directed edge formed along at least a portion of the outer periphery of the cavity.

Description

[451 May 1, 1973 United States Patent Greenhlatt et al.

'54] sorr somn FOOTWEAR Inventors: David Greenblatt, 135 Redwood 5:32 2; g gzgtzgz fig Lawson Allan Greenblatt, 5 Hickory Drive, Great Neck, N.Y. 11021 May 26, 1971 Dr., Roslyn, N.Y. 11576;

[22] Filed:

gral one-piece bottom, substantially the same thickness as the upper and preferably formed of injected molded thermoplastic composition. The bottom is provided with an integral upwardly extending peripheral sidewall portion overlying and bonded to a lower portion of the upper. The sidewall portion has an outer surface merging substantially continuously in rounded manner mw v 5 M4M "A "4 ".6 m m m d "H e un .n mmm C n S H e a m 8 m m e "m" .m 6 m h e M In R 3 n .e 0 ms qu m. .M 0. MR A UIF ll] 1 l. 2 8 6 2 555 5 l. ,lrLrL rt UNITED STATES PATENTS into the tread surface of the bottom. The mold assembly consists of a onepiece cavity mold having an inwardly directed edge formed along at least a portion of the outer periphery of the cavity.

.36/4 11 Claims, 5 Drawing Figures w t Hm 336 WW 2,498,437 2/l950 LHollier..,............................. 2,838,854 6/1958 Dosmann 3,27 l ,887 9/l966 Werman...... 3,293,494 12/1966 P atented May 1, 1973 2 Sheets-Sheext 1 FIG. 1

FIG. 2

FIG. 3

INVENTORS DAVID 'GREENBLATT ALLAN GREENBLATT ATTORNEYS Patent ed May 1, 19 73 2 Sheets-Sheet 2 FIG. 4

FIG. 5

ALLAN GREENBLATT ATTORNEYS soar-some FOOTWEAR BACKGROUND OF THE INVENTION The invention relates to articles of footwear and to a method and apparatus for applying integral sole-heel units to lasted uppers, and more particularly to a method and apparatus for injection molding to an appropriately styled upper, an integral sole-heel unit having the characteristic appearance of the soft-sole shoe.

The traditional soft-sole shoe is generally characterized by the absence of a distinct edge or edges formed in the outer sole portion. The outer sole is normally made from a reasonably soft and easily deformable and pliable composition, preferably the same material as the upper. This outer sole has heretofore been attached to the upper by stitching. The presence or appearance of such stitching tends further to characterize the footwear as being of the soft-sole variety.

Heretofore the manufacture of a soft-sole shoe has been a complicated, highly skilled and expensive operation. In particular, the method of forming and attaching the sole and heel portions to the upper portion has heretofore involved a plurality of time-consuming steps. At one assembly station, a first stitching operation involves connecting a spring heel, or wedge cover, to the pre-formed upper. The upper with attached spring heel is then passed to another station at which the outer sole is stitched to the spring heel and toe portion. Padding, such as a heel wedge or sole padding, may then be placed in position along the inner face of the outer sole and secured to the shoe by means of a sock lining, the attachment of which requires a third stitching operation. Since the edges of the various seams are concealed, each required seaming operation is performed with the outer, or right, faces of the material together such that the assembled shoe will be arranged with its inside facing out.

The assembled shoe must then be everted. Where leather and like materials are used to form the shoe, this eversion process requires a prior softening of the material of the shoe sufficiently to allow the accompanying deformation. Accordingly, the shoe is steamed for a period of time. The final step is to place the saturated shoe on a last for drying and shaping.

It may be seen that this prior method for making the soft-sole shoe involves a plurality of stitching operations and the time-cunsuming steaming, everting and shaping procedures. The performance of these various manufacturing steps has involved the expenditure of large amounts of time, effort and money with respect to personnel and equipment. Accordingly, the ability of shoe manufacturers to meet, at a reasonable price, the existing commercial demand for shoes of the soft-sole variety has heretofore been severely circumscribed.

Furthermore, it has been found that the utility of the traditional soft-sole shoe has been somewhat limited, owing to the composition of the chacteristic outer sole. The outer sole is typically of the same material as the upper portion of the shoe. Accordingly, such prior shoes have been unsuited for use out-of-doors where they would be subject to inclement conditions resulting in relatively severe wear and tear. Sharp and otherwise abrasive objects such as sticks or stones have frequently abused both shoe and wearer. Consequently, the attractive style and comfort of the traditional soft-sole shoe has been unduly limited to a shoe which serves essentially as an indoor slipper.

The effective life of the prior soft-sole shoe has been abridged by such traditional use of the same material for both the outer sole and the upper. Such an outer sole has simply not had sufficient strength or durability to absorb the punishment inherent in constant use, even within the relatively favorable indoor environment.

Accordingly, the present invention provides for a soft-sole having a one-piece composition outer sole, and a method and apparatus for injection molding such outer sole to a lasted upper. According to the invention, the outer sole may be attached to the upper in a single molding step. The invention, therefore, makes possible a significant saving in time, effort and expense in the manufacture of soft-sole shoes. The invention provides for a rigid one'piece cavity mold, the cavity of which has been sculptured or contoured to produce a sole having the soft-sole appearance. The one-piece mold eliminates the mold lines inherently produced by multi-pi ece molds having rings movable back and forth to engage the uppers in a sealing relationship. Such mold lines would blight the appearance of the shoe. Since the previously required stitching has been eliminated, the mold is preferably formed with appropriately positioned stitch marks so as to provide the cured sole-heel unit with the traditional appearance.

The molding apparatus is provided with a base member having a cavity formed therein and usual means for moving a lasted upper into the cavity. The mold may also be provided with sealing means integral with the base and engageable with a portion of the upper to form the molding cavity. Such sealing means preferably consists of a very slight lip at the perimeter of at least the toe portion of the sides of the mold for engaging the upper in a sealing relationship. The peripheral edge of the mold cavity may also suffice for this purpose. Conventional injection molding apparatus may be connected for filling the cavity with a bottomforming material after the upper is engaged by the sealmg means.

It is one object of the present invention to provide a soft-sole shoe having a unitary upper and an integral one-piece sole-heel unit.

Another object of the present invention is to provide a soft-sole shoe having a unitary upper and an injected molded one-piece sole-heel unit formed of thermoplastic material.

Still another object of the present invention is to provide a method and apparatus for making a soft-sole shoe.

Still another object of the present invention is to provide an injection-molding method and apparatus for making soft-sole shoes.

A further object of the present invention is to provide a method and apparatus for forming and attaching the sole of a soft-sole shoe in the single step of molding an integral sole-heel unit to a lasted upper.

A still further object of the present invention is to provide a one-piece molding apparatus for molding to lasted uppers, integral sole-heel units having the characteristic appearance of the sole of a soft-sole shoe.

Yet another object of the present invention is to provide molding apparatus for making soft-sole shoes which apparatus does not leave a mold line in the molded sole.

Another object of the present invention is to provide a shoe having the characteristic appearance of the softsole shoe, consisting of an integral sole-heel unit molded to a preformed upper.

BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of the present invention, reference may be had to the accompanying drawings, in which:

FIG. l is a perspective view of a mold apparatus employed in the method of the present invention for the molding of soles to a shoe;

FIG. 2 is a sectional elevation of a shoe and shoe mold in sole-molding relation;

FIG. 3 is a view taken along the line 33 of FIG. 2; and

FIG. 4 is a side elevation of a completed soft-sole shoe with integral sole-heel unit molded thereon;

FIG. 5 is a view taken along the line 5-5 of FIG. 4.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawing, and in particular to FIG. 1, there is illustrated a mold, generally indicated by reference numeral 10, particularly adapted for forming and molding an intergral sole-heel unit to a conventional prefabricated upper. The mold preferably includes a base member 11 having a shaped cavity, or recess, 12 formed therein. The bottom surface 13 of the recess may be shaped to form tread patterns 14, as desired, on the material to be molded therein. The bottom surface 13 includes a forward or toe portion 16 and a rear or heel portion 17, the latter being depressed below the general level of the toe. The bottom surface of the heel portion 17 may be designed to provide the same or a different type of heel tread pattern.

The continuous sidewall portion 18 of the recess 12 is contoured to conform to the desired shape of the sole to be molded. As described above, one of the characteristics of the soft-sole shoe is that the outer sole is formed without a distinct edge or edges. Accordingly, the sidewall 18 is somewhat curved, especially in the forward portion 16, as indicated by reference numeral 19, and meets the bottom surface 13 in a smooth continuous curve corresponding to the shape of the sole to be molded. This juncture between the sidewall 18 and the bottom surface 13 of the mold recess is somewhat more sharply defined within the depressed heel portion 17. Nevertheless, there is a relatively smooth and continuous transition from the sidewall to tread areas of the heel. It has been found that the appearance of the traditional soft-sole shoe is most closely realized by providing that the radius of curvature of the sidewalls 19a, at the heel portion of the sole, be substantially larger than the radius of curvature of the sidewalls 19 at the toe portion of the sole.

Referring now to FIGS. 2 and 3, there is illustrated the base member 11 with its recess 12 and sidewalls 19 in molding relation to an appropriately styled and preformed upper U of suitable material, such as leather, a woven fabric or a synthetic sheet material. The upper U is illustratively string lasted on a preferably metal last, generally indicated by reference numeral 21.

The rounded sidewall 19 preferably merges at its periphery into a very slight sealing nose or lip 23. In FIGS. 2 and 3, the curved sidewall 19 has been exaggerated somewhat in order readily to distinguish the lip 23, but it will be understood that the radius of curvature must be determined with respect to the particular type of material chosen to form the sole andheel unit of the shoe. For example, if the sides of the sole or heel unit would extend radially outwardly beneath too large a protrusion or lip 23, damage may result to the bottom-forming material upon withdrawal of the last 21 and upper U from the mold. Accordingly, the extent of protrusion of the lip 23 is preferably limited to correspond both to the shape of the sole of a traditional soft sole shoe and the degree of compressibility of the bottom-forming material. The lip 23 is preferably less distinct at the heel portion 17 of the mold.

In the preferred embodiment, the lateral dimensions of the last 21 relative to those of the perimeter of the recess 12 are such that when the last is moved into the recess, any clearance between the peripheral lip 23 and the last is less than the thickness of the upper U. The result is that when a lasted upper is brought toward the recess 12, the peripheral edge or lip 23 comes into contact with the upper U at a predetermined position on the sidewalls of the upper. Sufficient pressure may then be applied to the last 21 effectively to force the peripheral edge 23 into a sealing relationship with the upper.

With attainment of the sealing relationship, the clearance between the forward sole portion 16 of the recess and the bottom of the last 26 is preferably substantially equal to the thickness of the upper. The bottom-forming composition will consequently have the pliable characteristics inherent in the sole of the traditional soft-sole shoe.

As illustrated best in FIG. 1, the bottom-forming composition is injected into the cavity beneath the last 21 through an aperture 27 preferably located in the rear portion 17 of the recess 12. This aperture 27 is preferably arranged to be in the tread surface of the heel so that its imprint in the cured sole composition cannot be easily detected when the shoe is being worn.

The last 22 may be provided with a plurality of projections 24 which extend downwardly from the bottom 26 and into the cavity 12. The purpose of these projections is to mold a corresponding plurality of cavities or core holes into the bottom-forming composition which forms the heel portion of the sole-heel unit. Such molded cavities facilitate setting of the injected composition and provide a preferable spring action in the heel which tends to soften the transmission of impact forces to the wearer. If desired, a cavity 25 may be molded into the heel portion and subsequently provided with a suitably supportive heel wedge or the like.

It should be noted that a mold similar to the mold apparatus 10 may be provided having sidewalls which extend upwardly and slightly outwardly from the bottom surface 13. When the lasted upper U is inserted in such a mold, the sidewalls of the upper will engage the sloping sides of the mold at a predetermined point to form a sealed joint.

In operation, the pre-formed upper U is attached to the last 21, preferably by string-lasting techniques involving a drawstring which is arranged to form an inturned lasting margin at the bottom of the last. The last with upper attached is then moved toward the recess or cavity E2 of the mold base member 1111. As described above, this movement toward the recess 12 is terminated by sealing engagement, preferably between the peripheral edge or lip 23 and predetermined points along the side portion of the lasted upper. A molding cavity 28 of predetermined thickness is thereby formed beneath the last.

An appropriate thermoplastic bottom-forming composition is then injected through the aperture 27 into the cavity 28 under conditions of pressure and temperature suitable for injection molding. The injection pressure forces the composition to spread evenly throughout the cavity 28 until it rises over the inturned lasting margin up to the point of contact between the peripheral lip 23 and the side portions of the upper. After curing, the last 22 with its completed shoe is withdrawn from the mold.

Preferably the peripheral lip 23 is small enough so that the hardened sole-heel unit will undergo only slight compression from contact with the lip, so that the footwear may be withdrawn from the mold without any resultant damage. It should be noted that if the cured sole-heel unit were too hard, of if it were provided with an exaggeratedly protruding portion, any attempt to extract the completed footwear would result in the soleheel unit being damaged, if not torn completely away from the upper U. This problem is avoided in soft-sole shoe construction, since the sole-heel unit is characteristically reasonably soft and easily deformable.

Soft-sole footwear produced by the mold constructed according to the present invention is relatively free from mold flash or spew and, therefore, when the footwear is withdrawn from the mold, it is in excellent condition and may be dispatched to customers immediately after packing and without further processing. The present molding method, therefore, significantly reduces trimming and other manicuring requirements. There is, accordingly, a considerable saving in time, effort and expense over other injection-molding techniques.

FIGS. 4 and 5 illustrate a particular style of soft-sole shoe, constructed in accordance with the present invention and generally indicated by reference numeral 29. This shoe consists essentially of an appropriate preformed unitary upper U having an integral one-piece sole-heel unit or bottom 31 molded thereto. The upper U is preferably string lasted, thereby forming the inturned lasting margin 3% at the bottom of the last. The sole-heel unit 31, which is produced in accordance with the invention (FIG. 5) includes a tread portion 33 and an upwardly extending peripheral sidewall portion, indicated by reference numeral 32. The sidewall portion 32 overlies and is molded to the inturned lasting margin and a lower portion of the upper and has an outer surface which merges in a substantially continuous curve or rounded manner into the sole or tread portion 33. Preferably, the sole or forepart of the one-piece bottom 31 is substantially the'same thickness as the upper U.

Referring to FIG. d, the bottom is further provided with a sloping ramp portion 34 at the breast line of the heel. This ramp portion joins the respective tread surfaces of the sole and heel portions of the bottom in a continuous, smooth and attractive manner.

A rounded bead portion 36 is preferably provided at the boundary between the tread surface of the heel portion and sidewall portion of the bottom. The bead 36 extends around the periphery of the heel portion and along the lower marginal edges of the ramp portion 34 until it merges into the sidewall portion 32. Imitation stitching may be provided by molding, further to provide the characteristic appearance of the traditional soft-sole shoe. Such imitation stitching may be achieved by providing a plurality of tiny wedge-shaped promontories 37 spaced evenly along the boundary line between the sidewall portion 32 and the upper U. Preferably, the bottom 31 is further provided with a plurality of similar wedge-shaped promontories 38 spaced evenly along the line forming the boundary between the bead portion 36 and the sidewall portion 32. The only distinct edge line of the sole-heel unit 31 is the terminal line which forms the boundary between the unit 31 and the upper U. Preferably, this terminal or boundary line lies substantially within a lateral plane of the upper.

It should be noted that the sole-heel unit 31 may be molded onto an upper of any desired design, and that the present invention is not to be limited to the particular line or style of upper illustrated.

While the invention has been described by way of reference to the particular embodiments illustrated, it is apparent that modification may be made therein without departing from the scope of the following claims.

What is claimed is:

1. An article of footwear comprising:

an upper piece;

an integral one-piece outer sole unit including a heel tread portion and a sole tread portion and having an integral upwardly extending peripheral sidewall portion overlying and molded to a lower portion of said upper piece, said sidewall portion having an outer surface merging substantially continuously in rounded manner into the tread portions of said unit, the heel of said unit having an upwardly sloping ramp portion at its breast line for substantially continuously merging said heel tread portion with said sole tread portion; and

a rounded bead portion forming the boundary between said heel tread portion and said upwardly extending sidewall, said bead extending along the edge of said ramp portion to merge with said sidewall substantially adjacent said sole tread portion.

2. An article as in claim 1 wherein said outer sole unit further comprises a plurality of substantially wedge-shaped projections adjacent said bead portion and evenly spaced around and substantially perpendicular to the boundary line between said bead portion and said sidewall.

3. An article of footwear comprising:

an upper piece having a toe portion, a heel portion and an opening for reception of a foot, said upper piece including a depending sidewall portion having a maximum lateral periphery and a lower portion extending below said sidewall portion and converging to a smaller lateral periphery; and

a one-piece bottom having a tread surface and an upstanding peripheral sidewall portion extending smoothly and roundedly upwardly from said tread portion, said upstanding sidewall portion overlying and being integrally bonded to said lower portion of said upper piece along a line extending around said depending sidewall portion below the points of maximum lateral periphery, the maximum lateral periphery of said upstanding sidewall portion being substantially coextensive with a vertical plane tangent to said depending sidewall portion at its points of maximum lateral periphery.

4. An article as in claim 3 further comprising a sole portion forming the entire tread surface in the forepart of said article, and a heel portion forming the entire tread surface in the rear part of said article.

5. An article as in claim 4 wherein said sole portion is of substantially the same thickness as that of the material of said upper piece.

6. An article of footwear as in claim 5 wherein said heel portion has a thickness greater than that of said sole portion.

7. The article of claim 3 wherein the peripheral bonding edge of said upstanding sidewall portion lies substantially within a horizontal plane of the article of footwear spaced above said tread surface.

8. The article of claim 6 wherein said heel portion further comprises an upwardly sloping ramp portion at its breast line for substantially continuously merging the tread surface of said heel portion with the tread surface of said sole portion.

9. The article of claim 8 wherein said heel portion further comprises a rounded bead portion forming the boundary between the tread surface of said heel portion and said upstanding sidewall, said bead extending along the edge of said ramp portion to merge with said upstanding sidewall substantially adjacent said sole portion.

10. The article of claim 3 wherein said bottom further comprises a plurality of substantially wedgeshaped projections, evenly spaced around and substantially perpendicular to at least the peripheral bonding edge of said upstanding sidewall thereby to provide said bottom piece with the appearance of having been stitched to said upper piece.

11. An article as in claim 9 wherein said bottom further comprises a plurality of substantially wedgeshaped projections adjacent said bead and evenly spaced around and substantially perpendicular to the boundary line between said bead and said upstanding sidewall.

Claims

1. An article of footwear comprising: an upper piece; an integral one-piece outer sole unit including a heel tread portion and a sole tread portion and having an integral upwardly extending peripheral sidewall portion overlying and molded to a lower portion of said upper piece, said sidewall portion having an outer surface merging substantially continuously in rounded manner into the tread portions of said unit, the heel of said unit having an upwardly sloping ramp portion at its breast line for substantially continuously merging said heel tread portion with said sole tread portion; and a rounded bead portion forming the boundary between said heel tread portion and said upwardlY extending sidewall, said bead extending along the edge of said ramp portion to merge with said sidewall substantially adjacent said sole tread portion.

3. An article of footwear comprising: an upper piece having a toe portion, a heel portion and an opening for reception of a foot, said upper piece including a depending sidewall portion having a maximum lateral periphery and a lower portion extending below said sidewall portion and converging to a smaller lateral periphery; and a one-piece bottom having a tread surface and an upstanding peripheral sidewall portion extending smoothly and roundedly upwardly from said tread portion, said upstanding sidewall portion overlying and being integrally bonded to said lower portion of said upper piece along a line extending around said depending sidewall portion below the points of maximum lateral periphery, the maximum lateral periphery of said upstanding sidewall portion being substantially coextensive with a vertical plane tangent to said depending sidewall portion at its points of maximum lateral periphery.

10. The article of claim 3 wherein said bottom further comprises a plurality of substantially wedge-shaped projections, evenly spaced around and substantially perpendicular to at least the peripheral bonding edge of said upstanding sidewall thereby to provide said bottom piece with the appearance of having been stitched to said upper piece.

11. An article as in claim 9 wherein said bottom further comprises a plurality of substantially wedge-shaped projections adjacent said bead and evenly spaced around and substantially perpendicular to the boundary line between said bead and said upstanding sidewall.