BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for making an article of footwear, more particularly to a method for making an article of footwear that has an outsole including a thermoplastic skin and a filler pad surrounded by and bonded to the thermoplastic skin.
2. Description of the Related Art
A conventional method for making an article of footwear normally involves thermal molding of an assembly of an upper, an insole or a midsole, and an outsole in a mold such that the midsole or the outsole is softened during the molding operation for bonding to the upper. The conventional method is disadvantageous in that the time required for softening the midsole or the outsole is relatively long by virtue of the relatively large thickness of the midsole or the outsole.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a method for making an article of footwear that is capable of overcoming the aforementioned drawback.
According to the present invention, there is provided a method for making an article of footwear. The method comprises the steps of: preparing an upper that has a bottom peripheral edge; preparing a thermoplastic skin that has a base wall and a peripheral wall which extends from a periphery of the base wall in a transverse direction relative to the base wall and which confines an inner space therein, the peripheral wall having a shape that conforms to that of the bottom peripheral edge of the upper; preparing a filler pad that has a shape conforming to that of the base wall; mounting the upper on a last; preheating the thermoplastic skin to a softened state; and thermal molding the softened thermoplastic skin together with an assembly of the filler pad and the upper in a mold in such a manner that the peripheral wall of the thermoplastic skin is patterned and is bonded to the bottom peripheral edge of the upper and that the filler pad is fittingly received in the inner space and is bonded to the base wall and the peripheral wall of the thermoplastic skin.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate embodiments of the invention,
FIG. 1 is a block diagram illustrating consecutive steps of the first preferred embodiment of a method according to this invention for making an article of footwear;
FIG. 2 is a sectional view to illustrate how a filler pad is enclosed in a space between an upper and a skin of the article of footwear according to the first preferred embodiment of this invention;
FIG. 3 is a sectional view showing the filler pad of FIG. 2, which is made from two different materials;
FIG. 4 is a sectional view showing a wear-resistant pad, which is attached to a bottom of the skin of FIG. 2;
FIG. 5 is a block diagram illustrating consecutive steps of the second preferred embodiment of the method according to this invention;
FIG. 6 is a sectional view to illustrate how the skin is connected to the upper of the article of footwear according to the second preferred embodiment of this invention;
FIG. 7 is a sectional side view showing an article of footwear, which is modified from that of FIG. 6, and which includes reinforcing ribs formed on the skin;
FIG. 8 is a sectional bottom view showing the reinforcing ribs of FIG. 7; and
FIG. 9 is a sectional view to illustrate how the skin is connected to the upper of the article of footwear according to the third preferred embodiment of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
For the sake of brevity, like elements are denoted by the same reference numerals throughout the disclosure.
FIG. 1 is a block diagram showing consecutive steps of the first preferred embodiment of a method of this invention for making an article of footwear.
With reference to FIG. 2, the method includes the steps of: preparing an upper 10 that has a bottom peripheral edge 12 confining a bottom opening 14; applying an adhesive to a peripheral wall of the upper 10; binding an insole 13 to the bottom peripheral edge 12 of the upper 10; preparing a thermoplastic skin 22 that has a base wall 221 and a peripheral wall 222 which extends from a periphery of the base wall 221 in a transverse direction relative to the base wall 221 and which confines an inner space 223 therein, the peripheral wall 222 having a shape that conforms to that of the bottom peripheral edge 12 of the upper 10; preparing a filler pad 21 that has a shape conforming to that of the base wall 221; mounting the upper 10 on a last 30; attaching a tape 40 on the peripheral wall of the upper 10 above the bottom peripheral edge 12 of the upper 10 for preventing formation of flash on the peripheral wall of the upper 10; preheating the thermoplastic skin 22 to a softened state; thermal molding the softened thermoplastic skin 22 together with an assembly of the filler pad 21, the insole 13, the upper 10 and the tape 40 in a mold 100 in such a manner that the peripheral wall 222 of the thermoplastic skin 22 is patterned and is bonded to the bottom peripheral edge 12 of the upper 10 and that the filler pad 21 is fittingly received in the inner space 223 and is bonded to the base wall 221 and the peripheral wall 222 of the thermoplastic skin 22 so as to cooperate with the thermoplastic skin 22 to form an outsole 20 of the article of footwear; cooling the mold 100; removing the resultant article of footwear from the mold 100; trimming the article of footwear; and removing the tape 40 from the article of footwear. The preheating operation of the thermoplastic skin 22 can be carried out in the mold 100 so as to reduce the manufacturing time.
The thermoplastic skin 22 is preferably made from ethylene vinylacetate copolymer or thermoplastic urethane. The filler pad 21 can be made from plastic waste, such as polyurethane, ethylene vinylacetate copolymer, or rubber. FIG. 3 illustrates the structure of the filler pad 21 that includes a heel portion 24 and a toe portion 23 which are made from different materials that differ in elasticity.
With reference to FIG. 4, a wear-resistant pad 70 can be attached to a bottom surface of the base wall 221 of the thermoplastic skin 22 in the mold 100 during the molding operation.
FIG. 5 is a block diagram showing consecutive steps of the second preferred embodiment of the method of this invention. With reference to FIG. 6, unlike the method of the previous embodiment, a positioning block 111 is placed in the inner space 223 in the thermoplastic skin 22 during the molding operation, and is removed from the mold 100 after the molding operation for insertion of the filler pad 21 through the bottom opening 14 into the inner space 223. The insole 13 is subsequently laid on an upper surface of the filler pad 21 and is connected to the bottom peripheral edge 12 of the upper 10 after the molding operation according to the method of this embodiment.
FIGS. 7 and 8 illustrate the structure of the thermoplastic skin 22 that further includes a plurality of reinforcing ribs 224 formed on and projecting from the base wall 221 into the inner space 223. The filler pad 21 is formed with a plurality of grooves 211 for fittingly receiving the reinforcing ribs 224 so as to enhance the strength of the outsole 20.
FIG. 9 illustrates the third preferred embodiment of the method of this invention. Unlike the second preferred embodiment, the bottom peripheral edge 12 of the upper 10 extends to the base wall 221 of the thermoplastic skin 22, and the positioning block 111 is laid on the bottom peripheral edge 12 of the upper 10 and the base wall 221 of the thermoplastic skin 22. Similar to the previous embodiment, a wear-resistant pad can be attached to the bottom surface of the base wall 221 of the thermoplastic skin 22.
Since the outsole 20 of the article of footwear is divided into the thermoplastic skin 22 and the filler pad 21, and since the thermoplastic skin 22 is relatively thin as compared to the filler pad 21 and is the only one that is required to be preheated prior to the molding operation, the manufacturing time of the article of footwear can be reduced as compared to the aforementioned conventional method of the prior art. In addition, the filler pad 21 made from plastic waste is advantageous and offers much benefit to the reduction of plastic waste.
While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.
Patent Application
20050273948
