CA2153082A1 - Injection molded three-layer sole - Google Patents
Injection molded three-layer soleInfo
- Publication number
- CA2153082A1 CA2153082A1 CA002153082A CA2153082A CA2153082A1 CA 2153082 A1 CA2153082 A1 CA 2153082A1 CA 002153082 A CA002153082 A CA 002153082A CA 2153082 A CA2153082 A CA 2153082A CA 2153082 A1 CA2153082 A1 CA 2153082A1
- Authority
- CA
- Canada
- Prior art keywords
- layer
- injectable
- sole
- molded
- molded layer
- 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.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D35/00—Producing footwear
- B29D35/12—Producing parts thereof, e.g. soles, heels, uppers, by a moulding technique
- B29D35/14—Multilayered parts
- B29D35/142—Soles
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/02—Soles; Sole-and-heel integral units characterised by the material
- A43B13/04—Plastics, rubber or vulcanised fibre
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/02—Soles; Sole-and-heel integral units characterised by the material
- A43B13/12—Soles with several layers of different materials
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/02—Soles; Sole-and-heel integral units characterised by the material
- A43B13/12—Soles with several layers of different materials
- A43B13/122—Soles with several layers of different materials characterised by the outsole or external layer
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/02—Soles; Sole-and-heel integral units characterised by the material
- A43B13/12—Soles with several layers of different materials
- A43B13/125—Soles with several layers of different materials characterised by the midsole or middle layer
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
- A43B13/16—Pieced soles
-
- A—HUMAN NECESSITIES
- A43—FOOTWEAR
- A43B—CHARACTERISTIC FEATURES OF FOOTWEAR; PARTS OF FOOTWEAR
- A43B13/00—Soles; Sole-and-heel integral units
- A43B13/14—Soles; Sole-and-heel integral units characterised by the constructive form
- A43B13/22—Soles made slip-preventing or wear-resisting, e.g. by impregnation or spreading a wear-resisting layer
- A43B13/223—Profiled soles
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
Abstract
An injection molded three-layer sole for an article of footwear is disclosed. The three-layer sole comprises a top molded layer formed from an injectable plastics material. An intermediate molded layer is formed from an injectable plastics material in underlying adjoining relation to the top molded layer. The intermediate molded layer has a primary undersurface and at least one integral, downwardly depending plug portion terminating in a first contact patch. A bottom molded layer is formed from an injectable plastics material different from the injectable plastics material of the intermediate molded layer in underlying adjoining relation to the primary undersurface. The bottom molded layer has a second contact patch and at least one interiorly disposed opening through which the downwardly depending plug portion extends, with the first and second contact patches in substantial alignment one with the other. The material of the bottom molded layer is abrasion resistant, while the material of the intermediate layer is shock-absorbing and/or slip-resistant.
Description
r _ ~ 8 2 FIELD OF THE lNv~..lON
The present invention relates to an injection molded three-layer sole for attachment to an article of footwear, and more particularly to such an injection molded three-layer sole wherein the contact patch of the sole comprises more than one type of injectable plastics/rubber material.
BACRGROUND OF THE lNv~..ION
Footwear having injection molded two-layer soles, such as running shoes, winter boots, rain boots, work boots, and so on, is well known. Such injection molded two-layer soles are typically molded automatically through the use of a conventional two colour injection molding machine capable of injecting two different types of injectable plastics/rubber material into a mold, in sequential order, one type of injectable plastics/rubber material after the other, to form a top molded layer and a bottom molded layer. The material of the bottom molded layer is typically selected primarily for abrasion resistance, while the top molded layer may be chosen for other properties, such as flexibility, or shock resistance. The top molded layer may optionally be stitched to a fabric or leather upper to substantially complete the boot or shoe assembly, or may itself be molded so as to form the entire upper of the molded footwear item, as in, for example, children's rain boots.
It is also known to adhere functional or decorative portions to the undersurface of the bottom molded layer for either functional or aesthetic purposes, typically by way of a 2~308~
_ separate and independent gluing operation after the injectable plastics/rubber material has set, or by specific placement of the functional or decorative portion into the mold cavity prior to commencement of the injection process.
It is also known to have footwear, as stated above, having injection molded three-layer soles, such as in athletic shoes, winter boots, and work boots, for example. It is generally desirable with such three-layered sole construction that the bottom molded layer of a sole be highly abrasion resistant so as to not wear out after a short period of use, and that the intermediate molded layer be shock resistant to protect the feet and spine of the wearer from impact damage (particularly with sports or running shoes), and that the top molded layer be flexible for comfort and stitching or other joining to the upper of the footwear item, which upper may be constructed of leather, synthetic leather, or other textile materials.
While high abrasion resistance is desirable for the bottom molded layer, a compromise must typically be made in selecting the material of the bottom molded layer, as increasing the abrasion resistance of an injectable plastics/rubber material tends to reduce its slip-resistant properties. That is, with known plastic or rubber injection moulding materials suitable for use in the production of soles for footwear, the more abrasion resistant a material is, the harder and more slippery it becomes.
Thus, the most abrasion resistant injectable sole materials cannot be generally used for the bottom molded layer, as they are ~15~8~
_ too slippery for most users, particularly if the sole is designed for outdoor or industrial usage or other usage where wet, icy or other slippery surfaces are likely to be encountered. In contrast, injectable plastics or rubber materials exhibiting good slip-resistance properties are typically much softer than would be acceptable for use in a bottom mold layer, exhibiting premature wear. Accordingly, in the case of such three-layer soles, it is recently known to add a separate piece of relatively soft and slip-resistant material to the bottom molded layer of such an injection molded three-layer sole for the purpose of providing a relatively small contact patch that is highly slip-resistant under slippery conditions, such as might be encountered on snow, ice or in an industrial environment where lubricants and the like, might be spilled on a floor. Such a separate piece forms an insertable plug in the bottom molded layer of the sole.
One problem with injection molded three-layer soles having such plugs is that there is inherently an extra manufacturing step, namely positioning the plug into the mold prior to injection, or adhering the extra pieces to the contact patch of the bottom molded layer using an adhesive. Also, the extra pieces must be independently molded or otherwise formed on a separate molding line. The manufacturing process is therefore more lengthy, more complicated, and more costly.
Further, where discrete plugs are adhered to the bottom molded layer, as aforesaid, they can become loose or detached, over a period of time. Moreover, the relative size of the ~1~3~8~
contact patch of the slip-resistant plug relative to the entire area of the footwear sole must be kept relatively small, as the likelihood of detachment increases with increased size of the contact patch.
It is, therefore, an object of the present invention to provide, in a single injection process, an injection molded three-layer sole having a bottom moulded layer which contacts the ground when in use, which bottom moulded layer has both a first lo contact patch moulded from a slip-resistant relatively softer, shock-absorbing plastics material, and second a contact patch molded from a relatively high abrasion resistant plastics material.
It is a further object of the present invention to provide an injection molded three-layer sole as aforesaid, wherein the need for the use of adhesives or special mold inserts to provide for said first contact patch in the bottom moulded layer is eliminated.
It is yet a further object of the present invention to provide an injection molded three-layer sole as aforesaid, wherein the area of the first contact patch relative to the area of the remainder of the sole operatively in contact with the ground, can be relatively large.
2153~82 . _ 8UNMARY OF THE lNv~.llON
In accordance with the present invention there is provided an injection molded three-layer sole for integration into an articlé of footwear. The three-layer sole comprises a top molded layer, an intermediate molded layer and a bottom molded layer, all formed from an injectable plastics or rubber material that is at least different with respect to the bottom and intermediate molded layers. The intermediate molded layer is formed from a plastics/rubber material having a relatively high slip-resistance as compared to the material of bottom molded layer. The intermediate molded layer has a primary undersurface and an integral, downwardly depending plug portion terminating in a first contact patch. The bottom molded layer is formed from an injectable plastics or rubber material in underlying adjoining relation to the primary undérsurface. The bottom molded layer has a second contact patch and at least one interiorly disposed opening through which the downwardly depending plug portion extends, with the first and second contact patches in substantial alignment one with the other.
Other objects, advantages, featuresand characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the 2~53~82 . _ accompanying drawings, the latter of which is briefly described hereinbelow.
Figure 1 is a perspective view from below of a preferred embodiment of the injection molded three-layer sole of the present invention attached to an article of footwear;
Figure 2 is a side elevational view of the injection molded three-layer sole and attached article of footwear of Figure l;
Figure 3 is a bottom plan view of the injection molded three-layer sole of Figures 1 and 2;
Figure 4 is a sectional side elevational view of the injection molded three layer sole of Figure 1, taken along section line 4-4 of Figure 3;
Figure 5 is a sectional view of the injection molded three-layer sole of Figures 1-4, taken along section line 5-5 of Figure 4;
Figure 6 is a sectional view of the injection molded three-layer sole of Figure~ 1-5, taken along section line 6-6 of Figure 4; and, 2~3~82 Figure 7 is an exploded perspective view from below of a portion of the injection molded three-layer sole of Figure 1.
Reference will now be made to Figures 1 - 7, which show a preferred embodiment of the injection molded three-layer sole of the present invention, as indicated by the general reference numeral 20. As shown in Figures 1 - 6, the injection molded three-layer sole 20 is attached to an article of footwear, as indicated by the general reference numeral 22. The three-layer sole 20 comprises a top molded layer 30 formed from an injectable plastics or rubber material. The top molded layer 30 is adapted to be secured to the article of footwear 22, and in the preferred embodiment as shown, the top molded layer 30 is integrally formed with an enclosed toe portion 24. The upper 26 is constructed of leather, synthetic leather, or other textile material, or a combination thereof, and is secured to the top molded layer 30 by means of stitching 27. Other conventional fastening means may be used. A metal or plastic stiffener plate 32 and a metal or plastic stiffener toe cap 34 (see Figure 4) may routinely be provided in the top molded layer 30 for additional structural integrity.
An intermediate molded layer 40 is formed from an injectable plastics or rubber material, in underlying adjoining relation to the top molded layer 30. The intermediate layer 40 has a primary undersurface 42, as can be best seen in Figure 7, - 2~53~
an integral first downwardly depending plug portion 44, (compositely comprised in the preferred embodiment illustrated of six sub-portions 44' together spelling the word "BAFFIN") and an integral second downwardly depending plug portion 45 (compositely comprised as shown of six individual lug members 45'), with each of the first 44 and second 45 plug portions terminating in a first contact patch 46 (compositely comprised of the contact surfaces 46'). The first contact patch 46 is shaped and dimensioned for contact with the ground, when the article of footwear 22 is in conventional use. The first downwardly depending plug portion 44 and the second downwardly depending plug portion 45 are integrally formed with the remainder of the intermediate molded layer 40, as part of the same molding process.
A bottom molded layer 50 is formed from an injectable plastics or rubber material different from the injectable material of the intermediate molded layer 40. The bottom molded layer 50 is formed during the injection process in underlying adjoining relation to the primary undersurface 42 of the intermediate molded layer 40. The bottom molded layer 50 has a second contact patch 56 comprised as shown, of a plurality of generally planar sub-patches terminally defined on variously shaped lugs 60. In this manner the contact patch 56 is shaped and dimensioned for contact with the ground, when the article of footwear 22 is in conventional use.
~15 3 ~82 There is provided at least one interiorly disposed opening in the bottom molded layer 50. In the preferred embodiment shown, there is provided a first interiorly disposed opening 51, and a second interiorly disposed opening 52, as best seen in Figure 7. The first downwardly depending plug portion 44 extends through the first interiorly disposed opening 51, and the second downwardly depending plug portion 45 extends through the second interiorly disposed opening 52. The first contact patch 46 of the first 44 and second 45 downwardly depending plug portions and the second contact patch 56 of the bottom molded layer 50 are in substantial alignment one with the other, such that when the article of footwear 22 is in conventional use, the first contact patch 46 and the second contact patch 56 all generally contact the ground. In this manner, the injection molded three-layer sole 20 of the present invention is able to provide abrasion resistance through specific selection of the injectable plastics/rubber material of the bottom molded layer 50, and also able to provide resistance to slipping through specific selection of the injectable plastics or rubber material of the intermediate molded layer 40, as discussed more fully below.
An insert shank 58 may be integrally molded into the bottom molded layer 50 for purposes of flexural strength or aesthetics.
In the preferred embodiment, the top 30, intermediate 40, and bottom molded layers 50 are each made from a different _ g _ ~15~2 injectabIe plastic or rubber material as are known in the art, with the injectable materials preferably being synthetic butadiene/ styrene rubber compounds.
The top 30, the intermediate 40, and the bottom 50 molded layers are each preferably made from injectable plastics or rubber materials that demonstrate no significant cut growth when subjected to a standardized Ross Flex test of 150,000 flexes performed at 23C., and also that demonstrate that no significant cut growth when subjected to a standardized Ross Flex test of 100,000 flexes performed at -20C
The intermediate molded layer 40 is preferably made from a highly slip-resistant and shock absorbing injectable plastics or rubber material having a Shore "A" hardness of between 24 and 30. The injectable material of the intermediate layer 40 preferably has a density of about 0.95 - 1.00 g/cc, and a tensile strength of about 3.0 - 4.0 MPa. Further, the intermediate molded layer 40 is preferably made from an injectable plastics/rubber material having an elongation at break of about 650 - 750 %, when subjected to a standardized testing method made available by The American Society for Testing and Materials, Philadelphia, Pennsylvania, U.S.A., and identified by the following testing method number: ASTM D-412.
The bottom molded layer 50 is preferably made from an abrasion resistant injectable plastics or rubber material having a Shore "A" hardness of 57 - 63. The injectable material of the 2~3~82 bottom layer 50 preferably has a density of 0.95 - 1.00 g/cc and a tensile strength of about 5.0 - 6.0 MPa. Further, the bottom molded layer 50 is preferably made from an injectable plastics/rubber material having an elongation at break of about 400-600 %, when subjected to a standardized test according to ASTM test method number D-412. The bottom molded layer 50 is preferably made from an injectable plastics/rubber material having a tear strength of 35 - 40 kg/cm, when subjected to a standardized strength test according to ASTM test method number D-624, Die "C". Preferably, the injectable plastics/rubber material of the bottom molded layer 50 is highly abrasion resistant, having a volume loss of less than 200 mm3, when subjected to standardized DIN abrasion test number 53516, 1987, and which highly abrasion resistant injectable plastics/rubber material experiences about a 97% Abrasion Index when subjected to a standardized NBS abrasion test according to ASTM test method number D-1630.
The top molded layer 30 is preferably made from an ozone resistant medium hardness grade injectable plastics/rubber material having a Shore "A" hardness of about 47 - 53. The injectable plastics/rubber material of the top molded layer 30 preferably has a density of 0.90 - 0.95 g/cc, and a tensile strength of about 3.0 - 4.0 MPa. Further, the top molded layer 30 is preferably made from an injectable plastics/rubber material having an elongation at break of over 700% when subjected to a standardized test according to ASTM test method number D-412.
Also, the injectable plastics/rubber material of the top molded 2~53~2 layer 30 has a tear strength of about 20 - 25 kg/cm when subjected to a standardized strength test according to ASTM test method number D-624, Die "C".
The above described injectable plastics/rubber materials for each of the upper 30, intermediate 40 and bottom 50 moulded layers are injected sequentially into the footwear mould (not shown), one each at respective injection stations of a conventional three-colour injection moulding machine, such that the product removed from the mould essentially comprises a finished footwear sole having the slip-resistant contact patches 46 already moulded in place, without the need for separate insertion or attachment.
The present invention relates to an injection molded three-layer sole for attachment to an article of footwear, and more particularly to such an injection molded three-layer sole wherein the contact patch of the sole comprises more than one type of injectable plastics/rubber material.
BACRGROUND OF THE lNv~..ION
Footwear having injection molded two-layer soles, such as running shoes, winter boots, rain boots, work boots, and so on, is well known. Such injection molded two-layer soles are typically molded automatically through the use of a conventional two colour injection molding machine capable of injecting two different types of injectable plastics/rubber material into a mold, in sequential order, one type of injectable plastics/rubber material after the other, to form a top molded layer and a bottom molded layer. The material of the bottom molded layer is typically selected primarily for abrasion resistance, while the top molded layer may be chosen for other properties, such as flexibility, or shock resistance. The top molded layer may optionally be stitched to a fabric or leather upper to substantially complete the boot or shoe assembly, or may itself be molded so as to form the entire upper of the molded footwear item, as in, for example, children's rain boots.
It is also known to adhere functional or decorative portions to the undersurface of the bottom molded layer for either functional or aesthetic purposes, typically by way of a 2~308~
_ separate and independent gluing operation after the injectable plastics/rubber material has set, or by specific placement of the functional or decorative portion into the mold cavity prior to commencement of the injection process.
It is also known to have footwear, as stated above, having injection molded three-layer soles, such as in athletic shoes, winter boots, and work boots, for example. It is generally desirable with such three-layered sole construction that the bottom molded layer of a sole be highly abrasion resistant so as to not wear out after a short period of use, and that the intermediate molded layer be shock resistant to protect the feet and spine of the wearer from impact damage (particularly with sports or running shoes), and that the top molded layer be flexible for comfort and stitching or other joining to the upper of the footwear item, which upper may be constructed of leather, synthetic leather, or other textile materials.
While high abrasion resistance is desirable for the bottom molded layer, a compromise must typically be made in selecting the material of the bottom molded layer, as increasing the abrasion resistance of an injectable plastics/rubber material tends to reduce its slip-resistant properties. That is, with known plastic or rubber injection moulding materials suitable for use in the production of soles for footwear, the more abrasion resistant a material is, the harder and more slippery it becomes.
Thus, the most abrasion resistant injectable sole materials cannot be generally used for the bottom molded layer, as they are ~15~8~
_ too slippery for most users, particularly if the sole is designed for outdoor or industrial usage or other usage where wet, icy or other slippery surfaces are likely to be encountered. In contrast, injectable plastics or rubber materials exhibiting good slip-resistance properties are typically much softer than would be acceptable for use in a bottom mold layer, exhibiting premature wear. Accordingly, in the case of such three-layer soles, it is recently known to add a separate piece of relatively soft and slip-resistant material to the bottom molded layer of such an injection molded three-layer sole for the purpose of providing a relatively small contact patch that is highly slip-resistant under slippery conditions, such as might be encountered on snow, ice or in an industrial environment where lubricants and the like, might be spilled on a floor. Such a separate piece forms an insertable plug in the bottom molded layer of the sole.
One problem with injection molded three-layer soles having such plugs is that there is inherently an extra manufacturing step, namely positioning the plug into the mold prior to injection, or adhering the extra pieces to the contact patch of the bottom molded layer using an adhesive. Also, the extra pieces must be independently molded or otherwise formed on a separate molding line. The manufacturing process is therefore more lengthy, more complicated, and more costly.
Further, where discrete plugs are adhered to the bottom molded layer, as aforesaid, they can become loose or detached, over a period of time. Moreover, the relative size of the ~1~3~8~
contact patch of the slip-resistant plug relative to the entire area of the footwear sole must be kept relatively small, as the likelihood of detachment increases with increased size of the contact patch.
It is, therefore, an object of the present invention to provide, in a single injection process, an injection molded three-layer sole having a bottom moulded layer which contacts the ground when in use, which bottom moulded layer has both a first lo contact patch moulded from a slip-resistant relatively softer, shock-absorbing plastics material, and second a contact patch molded from a relatively high abrasion resistant plastics material.
It is a further object of the present invention to provide an injection molded three-layer sole as aforesaid, wherein the need for the use of adhesives or special mold inserts to provide for said first contact patch in the bottom moulded layer is eliminated.
It is yet a further object of the present invention to provide an injection molded three-layer sole as aforesaid, wherein the area of the first contact patch relative to the area of the remainder of the sole operatively in contact with the ground, can be relatively large.
2153~82 . _ 8UNMARY OF THE lNv~.llON
In accordance with the present invention there is provided an injection molded three-layer sole for integration into an articlé of footwear. The three-layer sole comprises a top molded layer, an intermediate molded layer and a bottom molded layer, all formed from an injectable plastics or rubber material that is at least different with respect to the bottom and intermediate molded layers. The intermediate molded layer is formed from a plastics/rubber material having a relatively high slip-resistance as compared to the material of bottom molded layer. The intermediate molded layer has a primary undersurface and an integral, downwardly depending plug portion terminating in a first contact patch. The bottom molded layer is formed from an injectable plastics or rubber material in underlying adjoining relation to the primary undérsurface. The bottom molded layer has a second contact patch and at least one interiorly disposed opening through which the downwardly depending plug portion extends, with the first and second contact patches in substantial alignment one with the other.
Other objects, advantages, featuresand characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the 2~53~82 . _ accompanying drawings, the latter of which is briefly described hereinbelow.
Figure 1 is a perspective view from below of a preferred embodiment of the injection molded three-layer sole of the present invention attached to an article of footwear;
Figure 2 is a side elevational view of the injection molded three-layer sole and attached article of footwear of Figure l;
Figure 3 is a bottom plan view of the injection molded three-layer sole of Figures 1 and 2;
Figure 4 is a sectional side elevational view of the injection molded three layer sole of Figure 1, taken along section line 4-4 of Figure 3;
Figure 5 is a sectional view of the injection molded three-layer sole of Figures 1-4, taken along section line 5-5 of Figure 4;
Figure 6 is a sectional view of the injection molded three-layer sole of Figure~ 1-5, taken along section line 6-6 of Figure 4; and, 2~3~82 Figure 7 is an exploded perspective view from below of a portion of the injection molded three-layer sole of Figure 1.
Reference will now be made to Figures 1 - 7, which show a preferred embodiment of the injection molded three-layer sole of the present invention, as indicated by the general reference numeral 20. As shown in Figures 1 - 6, the injection molded three-layer sole 20 is attached to an article of footwear, as indicated by the general reference numeral 22. The three-layer sole 20 comprises a top molded layer 30 formed from an injectable plastics or rubber material. The top molded layer 30 is adapted to be secured to the article of footwear 22, and in the preferred embodiment as shown, the top molded layer 30 is integrally formed with an enclosed toe portion 24. The upper 26 is constructed of leather, synthetic leather, or other textile material, or a combination thereof, and is secured to the top molded layer 30 by means of stitching 27. Other conventional fastening means may be used. A metal or plastic stiffener plate 32 and a metal or plastic stiffener toe cap 34 (see Figure 4) may routinely be provided in the top molded layer 30 for additional structural integrity.
An intermediate molded layer 40 is formed from an injectable plastics or rubber material, in underlying adjoining relation to the top molded layer 30. The intermediate layer 40 has a primary undersurface 42, as can be best seen in Figure 7, - 2~53~
an integral first downwardly depending plug portion 44, (compositely comprised in the preferred embodiment illustrated of six sub-portions 44' together spelling the word "BAFFIN") and an integral second downwardly depending plug portion 45 (compositely comprised as shown of six individual lug members 45'), with each of the first 44 and second 45 plug portions terminating in a first contact patch 46 (compositely comprised of the contact surfaces 46'). The first contact patch 46 is shaped and dimensioned for contact with the ground, when the article of footwear 22 is in conventional use. The first downwardly depending plug portion 44 and the second downwardly depending plug portion 45 are integrally formed with the remainder of the intermediate molded layer 40, as part of the same molding process.
A bottom molded layer 50 is formed from an injectable plastics or rubber material different from the injectable material of the intermediate molded layer 40. The bottom molded layer 50 is formed during the injection process in underlying adjoining relation to the primary undersurface 42 of the intermediate molded layer 40. The bottom molded layer 50 has a second contact patch 56 comprised as shown, of a plurality of generally planar sub-patches terminally defined on variously shaped lugs 60. In this manner the contact patch 56 is shaped and dimensioned for contact with the ground, when the article of footwear 22 is in conventional use.
~15 3 ~82 There is provided at least one interiorly disposed opening in the bottom molded layer 50. In the preferred embodiment shown, there is provided a first interiorly disposed opening 51, and a second interiorly disposed opening 52, as best seen in Figure 7. The first downwardly depending plug portion 44 extends through the first interiorly disposed opening 51, and the second downwardly depending plug portion 45 extends through the second interiorly disposed opening 52. The first contact patch 46 of the first 44 and second 45 downwardly depending plug portions and the second contact patch 56 of the bottom molded layer 50 are in substantial alignment one with the other, such that when the article of footwear 22 is in conventional use, the first contact patch 46 and the second contact patch 56 all generally contact the ground. In this manner, the injection molded three-layer sole 20 of the present invention is able to provide abrasion resistance through specific selection of the injectable plastics/rubber material of the bottom molded layer 50, and also able to provide resistance to slipping through specific selection of the injectable plastics or rubber material of the intermediate molded layer 40, as discussed more fully below.
An insert shank 58 may be integrally molded into the bottom molded layer 50 for purposes of flexural strength or aesthetics.
In the preferred embodiment, the top 30, intermediate 40, and bottom molded layers 50 are each made from a different _ g _ ~15~2 injectabIe plastic or rubber material as are known in the art, with the injectable materials preferably being synthetic butadiene/ styrene rubber compounds.
The top 30, the intermediate 40, and the bottom 50 molded layers are each preferably made from injectable plastics or rubber materials that demonstrate no significant cut growth when subjected to a standardized Ross Flex test of 150,000 flexes performed at 23C., and also that demonstrate that no significant cut growth when subjected to a standardized Ross Flex test of 100,000 flexes performed at -20C
The intermediate molded layer 40 is preferably made from a highly slip-resistant and shock absorbing injectable plastics or rubber material having a Shore "A" hardness of between 24 and 30. The injectable material of the intermediate layer 40 preferably has a density of about 0.95 - 1.00 g/cc, and a tensile strength of about 3.0 - 4.0 MPa. Further, the intermediate molded layer 40 is preferably made from an injectable plastics/rubber material having an elongation at break of about 650 - 750 %, when subjected to a standardized testing method made available by The American Society for Testing and Materials, Philadelphia, Pennsylvania, U.S.A., and identified by the following testing method number: ASTM D-412.
The bottom molded layer 50 is preferably made from an abrasion resistant injectable plastics or rubber material having a Shore "A" hardness of 57 - 63. The injectable material of the 2~3~82 bottom layer 50 preferably has a density of 0.95 - 1.00 g/cc and a tensile strength of about 5.0 - 6.0 MPa. Further, the bottom molded layer 50 is preferably made from an injectable plastics/rubber material having an elongation at break of about 400-600 %, when subjected to a standardized test according to ASTM test method number D-412. The bottom molded layer 50 is preferably made from an injectable plastics/rubber material having a tear strength of 35 - 40 kg/cm, when subjected to a standardized strength test according to ASTM test method number D-624, Die "C". Preferably, the injectable plastics/rubber material of the bottom molded layer 50 is highly abrasion resistant, having a volume loss of less than 200 mm3, when subjected to standardized DIN abrasion test number 53516, 1987, and which highly abrasion resistant injectable plastics/rubber material experiences about a 97% Abrasion Index when subjected to a standardized NBS abrasion test according to ASTM test method number D-1630.
The top molded layer 30 is preferably made from an ozone resistant medium hardness grade injectable plastics/rubber material having a Shore "A" hardness of about 47 - 53. The injectable plastics/rubber material of the top molded layer 30 preferably has a density of 0.90 - 0.95 g/cc, and a tensile strength of about 3.0 - 4.0 MPa. Further, the top molded layer 30 is preferably made from an injectable plastics/rubber material having an elongation at break of over 700% when subjected to a standardized test according to ASTM test method number D-412.
Also, the injectable plastics/rubber material of the top molded 2~53~2 layer 30 has a tear strength of about 20 - 25 kg/cm when subjected to a standardized strength test according to ASTM test method number D-624, Die "C".
The above described injectable plastics/rubber materials for each of the upper 30, intermediate 40 and bottom 50 moulded layers are injected sequentially into the footwear mould (not shown), one each at respective injection stations of a conventional three-colour injection moulding machine, such that the product removed from the mould essentially comprises a finished footwear sole having the slip-resistant contact patches 46 already moulded in place, without the need for separate insertion or attachment.
Claims (23)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An injection molded three-layer sole for footwear, said three-layer sole comprising:
a top molded layer formed from an injectable plastics/rubber material;
an intermediate molded layer formed from an injectable plastics/rubber material in underlying adjoining relation to said top molded layer, said intermediate molded layer having a primary undersurface and at least one integral, downwardly depending plug portion terminating in a first contact patch;
a bottom molded layer formed from an injectable plastics/rubber material different from the injectable plastics/rubber material of said intermediate molded layer in underlying adjoining relation to said primary undersurface; and, said bottom molded layer having a second contact patch and at least one interiorly disposed opening through which said at least one downwardly depending plug portion extends, with said first and second contact patches in substantial alignment one with the other.
a top molded layer formed from an injectable plastics/rubber material;
an intermediate molded layer formed from an injectable plastics/rubber material in underlying adjoining relation to said top molded layer, said intermediate molded layer having a primary undersurface and at least one integral, downwardly depending plug portion terminating in a first contact patch;
a bottom molded layer formed from an injectable plastics/rubber material different from the injectable plastics/rubber material of said intermediate molded layer in underlying adjoining relation to said primary undersurface; and, said bottom molded layer having a second contact patch and at least one interiorly disposed opening through which said at least one downwardly depending plug portion extends, with said first and second contact patches in substantial alignment one with the other.
2. The three-layer sole of claim 1, wherein said intermediate and bottom molded layers are each made from different injectable plastics/rubber materials.
3. The three-layer sole of claim 1 wherein said top, intermediate and bottom mold layers are each made from different injectable plastics/rubber materials.
4. The three-layer sole of claim 3, wherein said intermediate and bottom molded layers are each made from synthetic butadiene and styrene rubber compounds.
5. The three-layer sole of claim 4, wherein said intermediate molded layer is made from a highly slip-resistant injectable synthetic butadiene and styrene rubber compound having a Shore "A" hardness of between 24 and 30.
6. The three-layer sole of claim 5, wherein said intermediate molded layer is made from an injectable rubber compound having a density of 0.95 - 1.00 g/cc.
7. The three-layer sole of claim 6, wherein said intermediate molded layer is made from an injectable rubber compound having a tensile strength of 3.0 - 4.0 MPa.
8. The three-layer sole of claim 7, wherein said intermediate molded layer is made from an injectable rubber compound having an elongation at break of 650 - 700%.
9. The three-layer sole of claim 8, wherein said top, intermediate, and bottom molded layers are each made from injectable synthetic butadiene and styrene rubber compounds that demonstrate no significant cut growth when subjected to a standardized Ross Flex test, of 150,000 flexes, performed at 23°C.
10. The three-layer sole of claim 9, wherein said top, intermediate, and bottom molded layers are each made from injectable synthetic butadiene and styrene rubber compounds that demonstrate no significant cut growth when subjected to a standardized Ross Flex test, of 100,000 flexes, performed at -20°C.
11. The three-layer sole of claim 10, wherein said bottom molded layer is made from a generally slip resistant injectable rubber compound having a Shore "A" hardness of 57 - 63.
12. The three-layer sole of claim 11, wherein said bottom molded layer is made from an injectable rubber compound having a density of 0.95 - 1.00 g/cc.
13. The three-layer sole of claim 12, wherein said bottom molded layer is made from an injectable rubber compound having a tensile strength of 5.0 - 6.0 MPa.
14. The three-layer sole of claim 13, wherein said bottom molded layer is made from an injectable rubber compound having an elongation at break of 400 - 600%.
15. The three-layer sole of claim 14, wherein said bottom molded layer is made from an injectable rubber compound having a tear strength of about 35 - 40 Kg/cm.
16. The three-layer sole of claim 15, wherein said bottom molded layer is made from a highly abrasion resistant injectable rubber compound having a volume loss of less than 200 mm3 when subjected to standardized DIN abrasion test number 53516, 1987.
17. The three-layer sole of claim 16, wherein said bottom molded layer is made from a highly abrasion resistant injectable rubber compound experiencing 97% Abrasion Index when subjected to standardized NBS abrasion test according to ASTM test method number D-1630.
18. The three-layer sole of claim 17, wherein said top molded layer is made from an injectable rubber compound having a Shore "A" hardness of about 47 - 53.
19. The three-layer sole of claim 18, wherein said top molded layer is made from an injectable rubber compound having a density of 0.90 - 0.95 g/cc.
20. The three-layer sole of claim 19, wherein said top molded layer is made from an injectable rubber compound having a tensile strength of about 3.0 - 4.0 MPa.
21. The three-layer sole of claim 20, wherein said top molded layer is made from an injectable rubber compound having an elongation at break of over 700% when subjected to a standardized test according to ASTM test method number D-412.
22. The three-layer sole of claim 21, wherein said top molded layer is made from an injectable rubber compound having a tear strength of 20 - 25 Kg/cm when subjected to a standardized test according to ASTM test method number D-624, Die "C".
23. The three-layer sole according to claim 1, wherein a first integral downwardly depending plug portion is provided in the sole region and a second integral, downwardly depending plug portion is provided in the heel region of said intermediate molded member, and corresponding first and second interiorly disposed openings are provided in said bottom molded layer, through which openings said first and second downwardly depending plug portions respectively extend, as aforesaid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002153082A CA2153082A1 (en) | 1995-06-30 | 1995-06-30 | Injection molded three-layer sole |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002153082A CA2153082A1 (en) | 1995-06-30 | 1995-06-30 | Injection molded three-layer sole |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2153082A1 true CA2153082A1 (en) | 1996-12-31 |
Family
ID=4156159
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002153082A Abandoned CA2153082A1 (en) | 1995-06-30 | 1995-06-30 | Injection molded three-layer sole |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2153082A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4298943A1 (en) * | 2022-07-01 | 2024-01-03 | Honeywell International Inc. | Outsole for a footwear article |
-
1995
- 1995-06-30 CA CA002153082A patent/CA2153082A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP4298943A1 (en) * | 2022-07-01 | 2024-01-03 | Honeywell International Inc. | Outsole for a footwear article |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19980630 |