TECHNICAL FIELD

[0001] The invention relates to a method for attaching hook and loop material to shoe components, such as an upper and a sole, to allow show components to be attachable and interchangeable, which will allow the use of different soles for the same upper. The method can also be used for an attachable insert between the upper and the sole, which will allow a shoe to convert from a low to a high heel shoe.

BACKGROUND OF THE INVENTION

[0002] A number of shoe manufacturers, and independent inventors, have attempted to develop shoes with changeable or replaceable soles, or soles of varying heights, that are removable and replaceable on the bottom or the shoe upper or upper. In recent years the most common way to attempt to attach these replaceable components is with Velcro® or similar type "hook and loop" material, or modern variations such as "mushroom Velcro" which uses sheets of opposing and paired prongs. One sheet of the Velcro style material is placed on the top side of the sole, and the other sheet is placed on the bottom of the upper, and the components are attached by pressing the two components together.

[0003] Examples of shoes that use Velcro® or hook and loop material include U.S. Pat. No. 7,549,237 to Gallegos, which includes additional shock absorption material attached between the upper and the sole by hook and loop material. Another example is disclosed in U.S. Pub. No. 2003/0200675 to Gross, which discloses a "flip-flop" or sandal style shoe with removable layers that can be stacked to increase the height of the shoe. A third example is PCT/US2012/059655 to Mulholland, one of the inventors of this application, which discloses a convertible shoe that is convertible from a low to a high heel. Mulholland et al. 13 M 06

[0004] One problem encountered in this method is that there are numerous static and dynamic forces at play in the relationship between the upper and the sole of the shoe. When the wearer is walking there are dynamic forces that play out across the connection. Most people step down on their heels, and as they walk their weight shifts and the force on the shoe shifts forward to the toe. Most people don't step uniformly on their heel and transfer their weight in a straight line to their toes; rather there are often sideways forces or twisting forces. Some people are slightly "pigeon toed" and bear more of their weight on the outside of their foot, and hence the shoe. Others are the opposite. Some people push off from their toes squarely, while others impart a slight twist as they step forward. To hold successfully and consistently, the attachment between the upper and the sole must be able to withstand all of these forces.

[0005] There is an additional problem encountered with this type of attachment. When the wearer wants to change the sole they must pull apart the upper and sole portions, and this puts yet another force on the material. In this case the forces are directly on the bond between the Velcro layer and the shoe component. Typically the components are only attached and detached a couple of times a day, at most. Some days they may never be detached, but other days there may be many "attach/detach" cycles. The problem is that not only must the Velcro attachment withstand the forces associated with wearing the shoe and walking in it, but the attachment between the Velcro and the shoe component must also withstand these forces. Additionally this attachment between the Velcro sheet and the shoe component must withstand the forces associated with the "attach/detach" cycle.

[0006] One problem encountered in developing these types of shoes is that older style "hook and loop" Velcro was not sufficiently strong to consistently withstand these forces. There have been a number of prior art shoes with detachable components that were attached by Velcro, but none Mulholland et al. 13 M 06 have reached the market and stayed for any length of time. For example, U.S. Patent Application, Pub. No. 2003/0200675, to Gross, discloses a flat flip-flop style shoe with a number of in intermediate layers that can be added or removed to change the overall height of the shoe. The layers are ostensibly held in place by Velcro, which covers only a portion of the surfaces between the layers (best seen in FIG 1.). Another examples includes U.S. Pat. No. 7,549,237, to Gallegos, which includes an addable shock absorption layer and arch support layer, that is attached by Velcro. Neither shoe is on the market. There are any number of possible

explanations for this, but the difficultly of achieving a successful bond between the Velcro and the shoe components is certainly a possibility.

[0007] A number of modern types of Velcro, however, have sufficient attachment strength to hold the Velcro attachments together and therefore hold the sole component to the upper component. The Velcro that has proven the most successful is "Mushroom" style Velcro. But a new problem has been encountered. The forces of wearing the shoes and attaching and detaching the shoes often causes the attachment between the Velcro sheet and the shoe component to fail. Typically the Velcro, which comes in sheets of material, is cut to conform to the size and shape of the respective shoe component, and simply glued to the shoe component. It is typically glued with the same type of glue used to attach the standard upper to the standard sole portion of the shoe.

[0008] Most expensive or "high end" shoes are stitched or sown for a secure attachment, but less expensive shoes are simply glued. Glue works passably well in this situation, particularly considering that less expensive shoes are not expected to last for more than a couple of seasons, at best. There are a wide variety of glues or adhesives used for attaching shoe components. The most common is Polyurethane, or PU glue. Mulholland et al. 13 M 06

[0009] The addition of the Velcro layer seems to add additional forces. This is probably because there is a slight amount of give or movement caused by the Velcro attachment, which adds to the dynamic forces encountered by the shoe. This has proven unsuccessful, and the attachment has frequently failed. The attachment fails in two related ways. One common attachment failure is for the Velcro sheet to become detached. This causes wobble or looseness in the shoe. In some cases the entire sheet becomes detached and the shoe separates not at the Velcro but at the glued attachment between the Velcro and the shoe component. The other common failure is for part of the Velcro sheet to become detached while others remain attached, which can cause tearing or ripping or breaking of the Velcro sheet. There is a need, therefore, for a way to securely and reliably attach Velcro to a shoe component.

SUMMARY OF THE INVENTION

Technical Problem

[0010] When Velcro is glued directly to the shoe components in a multi-component shoe typically the Velcro will tear and come apart due to the forces encountered during normal wear. Solution to the Problem

[0011] The invention consists of a method of attaching Velcro securely and reliably to a shoe component. The method consists of adding a layer of cloth between the Velcro sheet and the shoe component. The cloth is first glued to the Velcro sheet and cured, and then the Velcro sheet with added cloth layer is glued to the shoe component and cured. The method consists of the type of cloth, the type of glue, and the specific gluing and curing process to ensure that the attachment is consistent and reliable.

Advantageous Effects of the Invention MulhoUand et al. 13 M 06

[0012] The addition of the layer of cloth allows the Velcro sheet to adhere securely and uniformly to the entire shoe component and eliminates any weak spots. This prevents the Velcro sheet from detaching or tearing and ensures a lengthy product life for a multi-component shoe that is attached by Velcro.

DESCRIPTION OF THE DRAWINGS

[0013] FIG 1 is an exploded perspective view showing the cloth layer and the Velcro sheet.

[0014] FIG 2 is an exploded cross section view of the cloth layer and the Velcro sheet.

[0015] FIG 3 is a cross section of the cloth layer attached to the Velcro sheet.

[0016] FIG 4 is an exploded perspective view showing the Velcro sheet and shoe component.

[0017] FIG 5 is an exploded cross section view of the Velcro sheet and shoe component.

[0018] FIG 6 is a cross section of the Velcro sheet attached to the shoe component.

[0019] FIG 7 is a perspective view of the underside attachment surfaces of the MulhoUand invention.

[0020] FIG 8 is a perspective view of the upper attachment surfaces of the MulhoUand invention. DESCRIPTION OF THE EMBODIMENTS

[0021] Detailed embodiments of the present invention are disclosed herein. It is to be

understood, however, that the disclosed embodiments are merely exemplary of the invention and that the invention may be embodied in various and alternative forms. Therefore, specified structural and functional details disclosed herein are not to be interpreted as limitations, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0022] The method consists broadly of gluing a cloth sheet to the back of the Velcro, and then gluing the back of the Velcro with the cloth attached to the shoe component. There are two types Mulholland et al. 13 M 06 of common Velcro. The first type consists of one sheet made of Tefion loops and the paired sheet made of polyester hooks. The second type consists of "mushroom" prongs where the mushroom shaped heads fit between the spaces made by the mushroom bodies. This process works with either conventional type of Velcro.

[0023] Step 1 : Attach fabric to back of the Velcro. The fabric 10 is glued to the back of the Velcro sheets 20. In the preferred embodiment the fabric 10 is standard canvas, which is a heavy woven fabric, typically made of cotton or linen. In the preferred embodiment cotton canvas is used. The canvas 10 is attached to the Velcro sheet 20 by means of hot melt glue. In the preferred embodiment the hot melt glue is ethylene vinyl acetate or EVA. Both canvas and Velcro comes in large spools of material, and in the preferred embodiment the fabric 10 is attached in large sheets of material as they are unspooled. The back 21 of the Velcro material has a relatively rough surface, and the fabric 10 is canvas, which is a relatively rough material. The glue adheres well between the material because the roughness gives plenty of surface for the glue to adhere.

[0024] Step 2: Cut the Velcro 20 with attached fabric 10 into the proper shape. This is done with standard shoe making cutting machinery which is designed to cut shoe components into the proper size and shape. In the preferred embodiment, the material is used with the convertible shoe disclosed in PCT/US2012/059655 to Mulholland. In the Mulholland invention the material is cut to be placed in the attachment field of the shoe components.

[0025] Step 3: Prepare the appropriate shoe surface. In the preferred embodiment the shoe component 40 is made of poured polyurethane (PU) material. The attachment surface 41 of the shoe component 40 is prepared by spreading a thin layer of Methylbenzene or Toluene onto the surface 41. In the preferred embodiment the Methylbenzene is applied by a brush or a cotton Mulholland et al. 13 M 06 swab. Methylbenzene is a solvent that can dissolve polyurethane. The thin layer of

Methylbenzene on the surface 41 will melt the surface 41. Methylbenzene also is an aromatic hydrocarbon with a high vapor pressure at room temperature, which means that it evaporates quickly. Therefore the thin layer of Methylbenzene will melt and crack the PU surface 41, and then evaporate, leaving the surface 41 rough and cracked. This improves the ability of the surface 41 to take glue and securely attach. The Methylbenzene is brushed on to the attachment surface and left to dissolve and evaporate. In the preferred embodiment, with the Mulholland invention, the attachment field is prepared with Methylbenzene.

[0026] Step 4: Clean the attachment surface 41 with alcohol by hand. Alcohol is applied to a clean wiping cloth, and the surface 41 is cleaned of any loose or foreign materials. The presence of dirt or any foreign material will adversely impact the bond between the material 30 and the surface 41.

[0027] Step 5: Apply glue to the surface 41 and the fabric 10 side of the paired material 30. A layer of glue is applied by brush onto both the PU surface 41 and the fabric side of the paired material 30. In the preferred embodiment one of two glues can be used. 3M® Scotch-Weld® Industrial Plastic Adhesive 4475 Clear, or Loctite® Vinyl, Fabric & Plastic Flexible Adhesive 1360694. Both work equally well. The material 30 and shoe component 40 are kept separate at this point.

[0028] Step 6: Place shoe component 40 with the glue in an oven at 60° Celsius (140°

Fahrenheit) for 3 to 5 minutes to allow the glue to become sticky and malleable. Then remove shoe component(s) from oven.

[0029] Step 7. Attach the material 30 to the attachment surface 41 of the shoe component 40. This is done by aligning the material to the attachment surface 41 so that they align properly. In Mulholland et al. 13 M 06 the preferred embodiment, with the Mulholland invention, the material 30 is lined up with the attachment surface. The material 30 is pressed against the attachment surface 41. There is glue on the material 30 and cured glue on the attachment surface 41. In one embodiment the material and shoe component 40 are pushed together with a clamping machine and held in place for one second. In an alternate embodiment the material 30 can be attached to the shoe component 40 by means of clamps placed around the shoe component 40. In an alternate embodiment sponge material can be used to protect the paired material 30 and shoe components 40.

[0030] The shoe components 40 with attached paired material 30 is cured at room temperature for 24 hours to allow bond to cure. Once cured the Velcro is attached with sufficient strength to allow use in shoe components.

[0031] FIGS 7 & 8 depict the Velcro attached to the shoe components of the Mulholland invention disclosed in PCT/US2012/059655. In this invention there is an insole 10, an insert 30, and a sole 50. The underside of the insole 10 and insert 30 have identical configurations, with a perimeter ridge 21 and attachment material 26. The topside of the insert 30 and sole 50 have identical configurations, with a perimeter channel 41 and attachment material 46. As described in the PCT application, the perimeter ridge 21 fits into the perimeter channel 41, and the upper attachment material 26 attaches to the lower attachment material 46 to secure the shoe components together. The method of attaching Velcro disclosed in this application allows the Velcro attachment material to be securely and permanently attached to the shoe components and to withstand the forces of walking in the shoes.

[0032] The present invention is well adapted to carry out the objectives and attain both the ends and the advantages mentioned, as well as other benefits inherent therein. While the present invention has been depicted, described, and is defined by reference to particular embodiments of Mulholland et al. 13 M 06 the invention, such reference does not imply a limitation to the invention, and no such limitation is to be inferred. The depicted and described embodiments of the invention are exemplary only, and are not exhaustive of the scope of the invention. Consequently, the present invention is intended to be limited only be the spirit and scope of the claims, giving full cognizance to equivalents in all respects.