Plastic and nonmetallic article shaping or treating: processes – Shaping or treating luminescent material
Reexamination Certificate
2001-01-05
2002-10-15
McDowell, Suzanne E. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Shaping or treating luminescent material
C264S515000, C264S516000, C264S535000, C264S536000, C264S540000, C264S541000
Reexamination Certificate
active
06464907
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to protective boots, and particular, to boots constructed for environmental protection and outdoor winter sports usage. The invention is intended to greatly reduce the weight to enhance winter athletic performance at greatly reduced cost.
2. Prior Art
The modern winter boot, particularly those used for hunting, ice fishing, snow shoeing, winter hiking, snow boarding, skiing, dog sledding, in-line skating and serious climbing are made up of a combination of many elements that have specific functions, all of which must work together for the support and protection of the foot. Winter sport boots today are varied in both design and purpose. Ski boots, Snowboard boots, winter hikers, snow shoeing boots, hunting boots, ice fishing boots, dog sledding boots, etc. all are designed to be used in very specific, and very different ways. They are also designed to provide a unique and specific combination of traction, warmth, water proofness, support and environmental protection to enhance performance. Not only are boots designed for specific sports, they are also designed to meet the specific characteristics of the user. For example, boots are designed differently for heavy duty usages than for light duty usages. The sport of skiing, versus ice fishing, impose totally different structural loads on the boot shell construction. It is therefore important to be able to adjust the characteristics of the various possible structural shell designs of the boot to accommodate these factors. It is also desirable to be able to minimize the weight of such structural shell designs so as to enhance outdoor winter performance (as well as summer usages.)
Generally, a protective boot is divided into 3 or 4 parts; the traction system, the shell, the upper, and the insulation or liner system (if applicable.) The traction system is generally natural rubber or a variety of synthetics (such as polyurethane) or co-polymers of both natural and synthetic elastomers. The insulation (if applicable) is produced as a “hung lining” inside the upper and shell, or consists of a removable liner or “bootie.” The “upper” may be of leather or synthetic materials (in the case of “Pac Boots”) or plastic (in the case of a Ski Boot “Cuff”.) Various upper constructions are possible, and in use at this time.
It is the shell, that we are most interested in exploring herein. Basically, five different types of shells exist today; an injection molded plastic shell (ski boots, in-line skates, serious climbing boots, etc.) an injection molded rubber (or synthetic) shell (pac boots, cycling boots, etc.), a vulcanized rubber shell (pac boots, waders, etc.), dipped rubber (or synthetic) shell footwear (ice fishing, waders), and injected polyurethane foam shell footwear (pac boots, etc.) Centrifugally molded footwear is scarce to non-existent in today's marketplace.
The function of the shell is the most crucial of all of the components that make up protective boots, particularly for outdoor sports usage. For ice fishing, the shell must be wind proof and waterproof. For skiing, the shell must be wind proof, water/snow proof, and also highly structural (stiff.) Abrasion and cut/tear resistance is also important Sunlight/UV protection and chemical resistance must be also considered. Cold crack flexibility and heat resistance are also required.
The integration of the shell to the other components of the boot (upper, midsole—if applicable and outersole) are also key considerations. For example, Pac Boots require that the shell contain a stitch flange (for sewing through) to enable attachment of the upper. Ski boots require that the shell be able to anchor and secure rivets for attachment of the (ankle) cuff. In-line skates require the same, of their shell. Bonding is also required for attachment of uppers as well as outersoles, Some pac boots incorporate “textile fibre knit socks” attached to the inside surface to reduce the surface friction within the shell assembly.
To achieve adequate shell functionality, as well as integration into the various end usages of the completed boots, is a daunting task. There are many limiting factors faced by today's designer. Among them are the following process limitations (with all currently used processes:)
Injection Molding
1. The thickness of the shell is too great at all of the “minimum desired thickness” areas (most of the whole shell.)
2. The shell is too heavy to achieve enough weight reduction for highly active sports usage.
3. The costs of finished parts as well as molds is very very high.
4. Mold series production time is too long.
Vacuum Forming
1. The shell must be produced in two parts, rather than one.
2. Thermoplastic welding is required to integrate the shell halves.
3. Weld reliability is always suspect, especially for cold weather impact and flexibility requirements.
4. Very few available materials exist in sheet form, for this process.
5. Parts are too expensive.
Centrifugal (Rotational) Molding
1. All corners of parts are too thick, due to process.
2. Pars are too heavy, due to above.
3. Parts are too expensive.
RF (FLOW) MOLDING
1. Deep 3D shape of parts is not achievable at all.
2. Proper materials are not sensitive to RF.
Injection molded boot shells are well known to the art. For example, U.S. Pat. No. 4,253,251, to Salomon, describes a rigid shelled ski boot containing an internal foot restraint system. The shell itself is too thick, too heavy, and too expensive for any sport except skiing. U.S. Pat. No. 4,279,044, to Colquaud, describes a polyurethane molding process which involves a 3 step “insert molding” process for sandals. This process cannot produce truly functional cold weather outdoor boot shells.
U.S. Pat. No. 5,647,150, to Romanato et al., describes an injection molding process for footwear shells, whereby a fabric sock becomes molded to the inside surface of the boot shell. Again, since the shell is injection molded, it is too thick, too stiff, and too expensive for anything but alpine ski boot usage. Additionally, U.S. Pat. No. 5,575,091, to Mattiuzzo, describes another injection molded ski boot application, this time employing a boot cuff with a rigidizing insert. Once again, an ultra stiff, heavy, and expensive boot shell results. U.S. Pat. No. 4,266,750, to Gallizia, describes a process for producing elastomeric boot shells but not plastic. Three separate shells are molded together, via an internal expandable bladder. This process produces boots far too heavy and expensive, only from non-plastic (elastomeric material.)
Additional prior art references relevant to this invention are:
U.S. Pat. No. 4,255,825, to Rigon, describes another injection molding process for plastic boots with rigid high heels.
U.S. Pat. No. 4,302,889, to Negrin, describes a boot to be worn after skiing. The novel feature here, seems to be the internally suspended lining system, within a shell.
U.S. Pat. No. 4,286,936, to Hustedt, describes an injection casting apparatus for shoe soles only. This process cannot produce a completed boot shell.
U.S. Pat. No. 4,224,708, to Becka, describes a machine for molding and flanging only the uppers of shoes. Again, this machine cannot produce a completed boot shell.
U.S. Pat. No. 4,266,314, to Londner espouse Ours, describes a method of manufacture of sports shoes involving two overlapping portions of plastic material overmolded onto a lining material, formed into the shape of a slipper. Adding a sole comprises a third step of this operation. This invention is far to labor intensive to be competitive in today's markets.
Furthermore, U.S. Pat. No. 4,301,564, to Dalebout, describes a novel method for producing inner boots that fit within an outer shell, but falls short of defining a process which produces the shell itself.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of this invention to provide a method for producing outdoor boot shells that can be as thin as 0.25 mm. Currently, no other method can produce them less than 1.0 mm thick on a consistent basis
Foley & Lardner
McDowell Suzanne E.
Wisconsin Alumni Research Foundation
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