CA2377082C - Method for making a footwear having a midsole surrounded by a cover sheet - Google Patents
Method for making a footwear having a midsole surrounded by a cover sheet Download PDFInfo
- Publication number
- CA2377082C CA2377082C CA002377082A CA2377082A CA2377082C CA 2377082 C CA2377082 C CA 2377082C CA 002377082 A CA002377082 A CA 002377082A CA 2377082 A CA2377082 A CA 2377082A CA 2377082 C CA2377082 C CA 2377082C
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- Canada
- Prior art keywords
- cover sheet
- mold
- inner cavity
- outsole
- midsole
- 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.)
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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
- B29D35/10—Producing footwear having preformed soles or heels joined on to preformed uppers using a moulding technique, e.g. by feeding or injecting plastics material between the parts to be joined
-
- 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
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Footwear And Its Accessory, Manufacturing Method And Apparatuses (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
Abstract
A method for making a footwear includes the steps of preparing an outsole, an upper and a cover sheet interconnecting the outsole and the upper via the cover sheet to form an inner cavity thereamong, placing the assembly of the outsole, the upper and the cover sheet in a mold, and filling a foamable material into the inner cavity and permitting the foamable material to expand to form a midsole and the cover sheet to expand to press against an inner wall of the mold.
Description
METHOD FOR MAKING A FOOTWEAR HAVING A MIDSOLE
SURROUNDED BY A COVER SHEET
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate an embodiment of the invention, Fig. 1 is a cross-sectional side view to illustrate a conventional method for making a shoe;
Fig. 2 is a cross-sectional side view to illustrate another conventional method for making a shoe ;
Fig. 3 is a block diagram to show consecutive steps of a method embodying this invention for making a footwear;
Figs. 4 and 5 illustrate how a midsole of the footwear is formed in a mold according to the method of this invention;
Fig. 6 is a fragmentary cross-sectional side view to illustrate cushioning pads which can be optionally embedded in the midsole of Fig . 5 according to the method of this invention;
Fig. 7 is a fragmentary cross-sectional side view to illustrate the cushioning pads of Fig. 6 in the form of air bag units that can be exposed from the footwear;
Figs. 8 to IO illustrate how a sandal is made according to the method of this inverition.
SURROUNDED BY A COVER SHEET
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate an embodiment of the invention, Fig. 1 is a cross-sectional side view to illustrate a conventional method for making a shoe;
Fig. 2 is a cross-sectional side view to illustrate another conventional method for making a shoe ;
Fig. 3 is a block diagram to show consecutive steps of a method embodying this invention for making a footwear;
Figs. 4 and 5 illustrate how a midsole of the footwear is formed in a mold according to the method of this invention;
Fig. 6 is a fragmentary cross-sectional side view to illustrate cushioning pads which can be optionally embedded in the midsole of Fig . 5 according to the method of this invention;
Fig. 7 is a fragmentary cross-sectional side view to illustrate the cushioning pads of Fig. 6 in the form of air bag units that can be exposed from the footwear;
Figs. 8 to IO illustrate how a sandal is made according to the method of this inverition.
BACKGROUND OF THE INVENTION
1. Field of the invention This invention relates to a method for making a footwear, more particularly to a method for making a footwear having an outsole, an upper, and a midsole that is surrounded by a cover sheet:
2. Description of the related art Fig. 1 illustrates a conventional method for making a shoe including an upper 4 , an outsola 3 , and a midsole 5 interconnecting the upper 4 and the outsole 3. The midsole 5 has a base portion 51 in contact with and bonded to the outsole 3, and an upper flange portion 52 extending upwardly from the base portion 51 and banded to a bottom portion 41 of the upper 4. The method employs a mold 10 including an upper mold part with a last 12, a bottom mold part 11, and side mold parts, which define a mold cavity 13. The midsole 5 is formed by filling a foamable material into an inner cavity 130 that is confined by the outsole 3, the upper 4, and inner walls of the side mold parts.
The midsole 5 normally includes filler (not shown) in the form of pellets which are disposed on the outsole 3 in the mold. cavity 13 :before the closing of the mold parts and which are enclosed by the midsole 5 during the formation of the same.
The aforesaid method for making the shoe is disadvantageous in that the pellets of the filler tend to move in the inner cavity 13 during filling of the foamable material. As a consequence, some of the pellets may protrude outwardly from an outer surface of the upper flange portion 52 of the midsole 5, thereby adversely affecting the appearance of the shoe. Moreover, since the upper flange portion 52 of the midsole 5 is exposed, it tends to deteriorate and discolor.
Fig. 2 illustrates a shoe prepared by a method that is disclosed in European Patent No. 0830935. The method uses an outsole 6 that has a flange portion 601 extending to and cooperating with a peripheral side wall 701 of an upper 7 to confine an inner cavity 60 therebetween. The upper 7 and the outsole 6 are placed in a mold 10. A midsole is formed in the inner cavity 60 by filling a foamable material into the inner cavity 60. A sealing member 8 is employed to press a tip portion 602 of the flange portion 601 against the peripheral side wall '701 of the upper 7 so as to prevent formation of flash on an exterior of the inner cavity 60. The conventional method is disadvantageous in that a precise match between an inner wall of the mold 10 and an outer surface of the flange portion 601 is needed prior to the formation of the midsole in order to permit t:he flange portion 601 of the outsole 6 to have a shape conforming to the inner wall of the mold 10. Moreover, it is relatively difficult to form a precise pattern on the outer surface of the flange portion 601 of the outsole 6 according to the conventional method.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a method for making a footwear that is capable of overcoming the aforementioned drawbacks.
According to the present invention, a method for making a footwear. comprises the steps of : preparing an out sole having a peripheral side wall; preparing an upper that is vertically aligned with and that is spaced apart from the outsole and that has a peripheral side wall; preparing a flexible elongated cover sheet that is disposed between and that interconnects the peripheral sides walls of the out sole and the upper so as to confine an inner cavity among the outsole, the upper, and. the cover sheet, the cover sheet being expandable outwardly of the inner cavity when an inner pressure in the inner cavity is increased; preparing a mold that has an inner wall defining a mold cavity, an upper mold part with a last, a bottom mold part opposite to the upper mold part, and at least two opposite side mold parts;
placing an assembly of the outsole, the upper, and the cover sheet in the mold cavity such that the out sole is mounted on the bottom mold part, that the S
upper is fittingly sleeved on the last, and that the cover sheet confronts the side mold parts; and filling a foamable material into the inner cavity and permitting curing and expansion of the foamable material to take place and to form a midsole bonded to the upper, the outsole, and the cover sheet, which, in turn, increases the inner pre~;sure in the inner cavity to result in expansion of the cover sheet, and which permits the cover sheet to press against the inner wall of the mold and to form into a shape that conforms to the inner wall of the mold.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. 3 shows consecutive steps of a method embodying this invention for making a shoe . Figs . 4 to 6 illustrate how a midsole 40 of the shoe is formed according to the method of this invention. The method includes the steps of : preparing an outsole 20 having a peripheral side wall 202 ; preparing an upper 3 0 that is vertically aligned with and that is spaced apart from the outsole 20 and that has a peripheral side wall 301; preparing a flexible elongated cover sheet 21 that is disposed between and that interconnects the peripheral side walls 202, 301 of the outsole 20 and the upper 30 so as to confine .an inner cavity 90 among the outsole 2 0 , the upper 3 0 , and the cover sheet 21, the cover sheet 21 being expandable outwardly of the inner cavity 90 when an inner pressure in the inner d cavity 90 is increased; preparing a mold 100 that has an inner wall 101 defining a mold cavity 102 , an upper mold part 111 with a last 110, a bottom mold part 112 opposite to the upper mold part lll, and at least two opposite side mold parts 113; placing an assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 such that the outsole 20 is mounted on the bottom mold part 112, that the upper 30 is fittingly sleeved on the last 110, and that the cover sheet 21 confronts the side mold parts 213 ; and filling a foamable material into the inner cavity 90 by injecting the foamable material from a feeding device 200 through a feeding channel 130 and permitting curing and expansion of the foamable material to take place and to form the midsole 40 bonded to the upper 30, the outsole 20, and the cover sheet 21, which, in turn, increases the inner pressure in the inner cavity 90 to result in expansion of the cover sheet 21, and which permits the cover sheet 21 to press against the inner wall 101 of the mold 100 and to form into a shape that conforms to the inner wall 101 of the -mold 100. It is noted that the air in the inner cavity 90 is simultaneously evacuated through vent-holes (not shown ) and is discharged to an exterior of the mold 100 in such. a manner that the inner pressure in the inner cavity 90 is sufficient to press the cover sheet 21 against the inner wall 101 of the mold 100 during the expansion of the foamable material.
Preferably, the peripheral side walls 202 , 301 of the outsole 20 and the upper 30 are adhesively bonded to the cover sheet 21 so as to be interconnected by the same before placing the same in the mold cavity 102. More preferably, the peripheral side wall 202 of the outsole 20 is adhesively bonded to the cover sheet 21, and the peripheral side wall 301 of the upper 30 is stitched to the cover sheet 21 . A pair of sealing strips 140, 150 are used to surround the tip portion of the cover strip 21 so as to seal a seam between the tip portion of the cover sheet 21 and the upper 30.
The cover sheet 21 can be made from ethylene vinylacetate copolymer, polyurethane, rubber, resilient cloth, leather, and the like. Preferably, the cover sheet 21 is made from ethylene vinyl acetate copolymer, and has a thickness in a range of from 0 . 5mm to 8.Omm, and more preferably in a range from l.Omm to S.Omm. The foamable material preferably is a mixture of polyo:ls and isocyanate so as to form the midsole 40 of polyurethane.
The mold 100 is preferably operated at a molding temperature in a range of from 40 to 120°C for forming the midsole 40 of polyurethane with the cover sheet 21 made from ethylene vinylacetate copolymer. The inner wall 101 of the mold 100 can be patterned so that when the cover sheet 21 is p~:essed against and is heated by the mold 100 upon foaming of the foamable material in the mold 100, the cover sheet 21 can be patterned as well. Since the cover ;sheet 21 is pressed S against the inner wall 101 of the mold 100, the pattern formed on the cover sheet 21 can precisely conform to that of the inner wall 101 of the mold 100.
Preferably, an inert gas is filled into the inner cavity 90 prior to the injection of the foamable material into the inner cavity 90 so as to enhance the pressing of the cover sheet 21 against the inner wall 101 of the mold 100 during the forming of the midsole 40 in the inner cavity 90.
The method of this invention can further include a step of loading a filler 45 (see Fig. 6) in the inner cavity 90 before placing the assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 so that the filler 45 will be embedded in the midsole 40 after formation of t:he midsole 40. The filler 45 can be in the form of pellets; and can be made of a plastic material selected from a group consisting of ethylene vinylacetate copolymer, rubber, and polyurethane.
Referring now to Fig . 7 , in combination with Fig .
6, the method of this invention can further include a step of disposing a plurality of cushioning pads 50, such as air bag units, in the inner cavity 90 before placing the assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 so that the cushioning pads 50 can be embedded in the midsole 40 after formation of the midsole 40. Each cushioning pad 50 can have extensions 51 extending through the cover sheet 21 so as to be exposed from the cover sheet 21. As such, the inner wall 101 of the mold 100 is provided with positioning holes 10:3 for receiving the extensions 51 during the formation of the midsole 40.
Preferably, the extensions 51 a re provided with sleeves 62 which are received in the positioning holes 103 during the formation of the midsole 40.
Thefollowing Examples illustrate the advantage of using the cover sheet 21 according to the method of this invention.
Example 1 Material of the cover sheet: ethylene vinylacetate copolymer.
Thiclmess of the cover sheet: 2.0 mm.
Shape of the inner wall of the nbld: concave with shallow pattern.
Foamable material: polyols and isocyanate Arr~unt of the foarnable material: 133 grams.
Molding temperature: 50~C.
Molding time: '7 minutes.
Result: Density of the midsole is 0.:34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 2 Material of the cover sheet: ethylenevinylacetate copolymer.
Thicl~ess of the cover sheet: 5.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature: 70°C.
Molding time: '7 minutes.
Result: Density of the midsole is 0.:34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 3 Material of the cover sheet : ethylene vinylacetate copolymer.
Thicl~.ess of the cover sheet: 8.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature: 120°C.
Molding time: S minutes.
Result: Density of the rnidsole is 0.34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 4 Material of the cover sheet: ethylene vinylacetate copolymer.
Thicl~.ess of the cover sheet: 5.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature : 12 0 °C .
Molding time: 5 minutes.
Result: Density of the midsole is 0.34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
The inventor of this application found that when the thickness of the cover sheet of ethylene vinylacetate copolymer is less than 0.5 mm and the molding temperature is above room temperature, the cover sheet tends to break, which leads to the formation of flash on the seam between the cover sheet and the upper, and that when the thickness of the cover sheet of ethylene vinylacetate copolymer is greater than 9 . Omm; the cover sheet is dif f icult to be shaped during the molding process even at a molding temperature of about 120°C. Moreover, when molding proceeds at room temperature, poor~profile of and obscure pattern on the cover sheet of ethylene vinylacetate copolymer result dueto poorflexibility of the ethylene vinylacetate copolymer under room temperature. The drawback can be overcome by using polyurethane film as the cover sheet, which is relatively soft and flexible under room temperature.
Figs. 8 to 10 illustrate how a sandal is made according to the method of this invention. The sandal includes an outsole 20' , an upper 30' with an upper flange 21' disposed over and connected to the out sole 20' , a midsole 40' formed according to the method of this invention and enclosed by th.e outsole 20' and the upper 30' , and a strap unit 31' having four end portions 32'. The function of the upper flange 21' is similar to that of the cover sheet 21 shown in Fig. 4.
The outsole 20' is provided with a pair of linking straps 24' having end portions which are stitched onto the end portions 32' of the strap unit 31' . The upper 30' is formed with four slits 411' for passage of the end portions of the linking straps 24' .
Before the formation of the midsole 40', the upper 30' and the outsole 20' are respectively mounted on the upper mold part 111' and the bottom mold part 112' , and four positioning sleeves 26' and four support sleeves 25' are provided and are disposed in a manner that the four positioning sleeves 26' extend through the upper mold part 111' and respectively into the slits 411', that the four support sleeves 25' are disposed between the outsole 20' and the upper 30' at the slits 411' and respectively receive the end portions of the linking straps 24' , and that the end portions of the linking straps 24' extend outwardly of the upper mold part 111' through the positioning sleeves 26' . After the formation of the midsole 40' , the positioning sleeves 26' can be removed from the upper mold part 111', and the end portions of the linking straps 24' can be stitched onto the end portions 32' of the strap unit 31' after removal of the upper and bottom mold parts 111' , 112' . It is noted that the end portions 32' of the strap unit 31' can be stitched onto the end portions of the linking straps 24' and the thus formed assembly is then disposed in the mold cavity 90' for subsequent processing steps for the formation of the midsole 40' .
By using the cover sheet 21 according to the method of this invention, the aforesaid drawbacks as encountered in the prior art can be eliminated.
With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention. It is therefore intended that the invention be limited only as recited in the appended claims.
1. Field of the invention This invention relates to a method for making a footwear, more particularly to a method for making a footwear having an outsole, an upper, and a midsole that is surrounded by a cover sheet:
2. Description of the related art Fig. 1 illustrates a conventional method for making a shoe including an upper 4 , an outsola 3 , and a midsole 5 interconnecting the upper 4 and the outsole 3. The midsole 5 has a base portion 51 in contact with and bonded to the outsole 3, and an upper flange portion 52 extending upwardly from the base portion 51 and banded to a bottom portion 41 of the upper 4. The method employs a mold 10 including an upper mold part with a last 12, a bottom mold part 11, and side mold parts, which define a mold cavity 13. The midsole 5 is formed by filling a foamable material into an inner cavity 130 that is confined by the outsole 3, the upper 4, and inner walls of the side mold parts.
The midsole 5 normally includes filler (not shown) in the form of pellets which are disposed on the outsole 3 in the mold. cavity 13 :before the closing of the mold parts and which are enclosed by the midsole 5 during the formation of the same.
The aforesaid method for making the shoe is disadvantageous in that the pellets of the filler tend to move in the inner cavity 13 during filling of the foamable material. As a consequence, some of the pellets may protrude outwardly from an outer surface of the upper flange portion 52 of the midsole 5, thereby adversely affecting the appearance of the shoe. Moreover, since the upper flange portion 52 of the midsole 5 is exposed, it tends to deteriorate and discolor.
Fig. 2 illustrates a shoe prepared by a method that is disclosed in European Patent No. 0830935. The method uses an outsole 6 that has a flange portion 601 extending to and cooperating with a peripheral side wall 701 of an upper 7 to confine an inner cavity 60 therebetween. The upper 7 and the outsole 6 are placed in a mold 10. A midsole is formed in the inner cavity 60 by filling a foamable material into the inner cavity 60. A sealing member 8 is employed to press a tip portion 602 of the flange portion 601 against the peripheral side wall '701 of the upper 7 so as to prevent formation of flash on an exterior of the inner cavity 60. The conventional method is disadvantageous in that a precise match between an inner wall of the mold 10 and an outer surface of the flange portion 601 is needed prior to the formation of the midsole in order to permit t:he flange portion 601 of the outsole 6 to have a shape conforming to the inner wall of the mold 10. Moreover, it is relatively difficult to form a precise pattern on the outer surface of the flange portion 601 of the outsole 6 according to the conventional method.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a method for making a footwear that is capable of overcoming the aforementioned drawbacks.
According to the present invention, a method for making a footwear. comprises the steps of : preparing an out sole having a peripheral side wall; preparing an upper that is vertically aligned with and that is spaced apart from the outsole and that has a peripheral side wall; preparing a flexible elongated cover sheet that is disposed between and that interconnects the peripheral sides walls of the out sole and the upper so as to confine an inner cavity among the outsole, the upper, and. the cover sheet, the cover sheet being expandable outwardly of the inner cavity when an inner pressure in the inner cavity is increased; preparing a mold that has an inner wall defining a mold cavity, an upper mold part with a last, a bottom mold part opposite to the upper mold part, and at least two opposite side mold parts;
placing an assembly of the outsole, the upper, and the cover sheet in the mold cavity such that the out sole is mounted on the bottom mold part, that the S
upper is fittingly sleeved on the last, and that the cover sheet confronts the side mold parts; and filling a foamable material into the inner cavity and permitting curing and expansion of the foamable material to take place and to form a midsole bonded to the upper, the outsole, and the cover sheet, which, in turn, increases the inner pre~;sure in the inner cavity to result in expansion of the cover sheet, and which permits the cover sheet to press against the inner wall of the mold and to form into a shape that conforms to the inner wall of the mold.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. 3 shows consecutive steps of a method embodying this invention for making a shoe . Figs . 4 to 6 illustrate how a midsole 40 of the shoe is formed according to the method of this invention. The method includes the steps of : preparing an outsole 20 having a peripheral side wall 202 ; preparing an upper 3 0 that is vertically aligned with and that is spaced apart from the outsole 20 and that has a peripheral side wall 301; preparing a flexible elongated cover sheet 21 that is disposed between and that interconnects the peripheral side walls 202, 301 of the outsole 20 and the upper 30 so as to confine .an inner cavity 90 among the outsole 2 0 , the upper 3 0 , and the cover sheet 21, the cover sheet 21 being expandable outwardly of the inner cavity 90 when an inner pressure in the inner d cavity 90 is increased; preparing a mold 100 that has an inner wall 101 defining a mold cavity 102 , an upper mold part 111 with a last 110, a bottom mold part 112 opposite to the upper mold part lll, and at least two opposite side mold parts 113; placing an assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 such that the outsole 20 is mounted on the bottom mold part 112, that the upper 30 is fittingly sleeved on the last 110, and that the cover sheet 21 confronts the side mold parts 213 ; and filling a foamable material into the inner cavity 90 by injecting the foamable material from a feeding device 200 through a feeding channel 130 and permitting curing and expansion of the foamable material to take place and to form the midsole 40 bonded to the upper 30, the outsole 20, and the cover sheet 21, which, in turn, increases the inner pressure in the inner cavity 90 to result in expansion of the cover sheet 21, and which permits the cover sheet 21 to press against the inner wall 101 of the mold 100 and to form into a shape that conforms to the inner wall 101 of the -mold 100. It is noted that the air in the inner cavity 90 is simultaneously evacuated through vent-holes (not shown ) and is discharged to an exterior of the mold 100 in such. a manner that the inner pressure in the inner cavity 90 is sufficient to press the cover sheet 21 against the inner wall 101 of the mold 100 during the expansion of the foamable material.
Preferably, the peripheral side walls 202 , 301 of the outsole 20 and the upper 30 are adhesively bonded to the cover sheet 21 so as to be interconnected by the same before placing the same in the mold cavity 102. More preferably, the peripheral side wall 202 of the outsole 20 is adhesively bonded to the cover sheet 21, and the peripheral side wall 301 of the upper 30 is stitched to the cover sheet 21 . A pair of sealing strips 140, 150 are used to surround the tip portion of the cover strip 21 so as to seal a seam between the tip portion of the cover sheet 21 and the upper 30.
The cover sheet 21 can be made from ethylene vinylacetate copolymer, polyurethane, rubber, resilient cloth, leather, and the like. Preferably, the cover sheet 21 is made from ethylene vinyl acetate copolymer, and has a thickness in a range of from 0 . 5mm to 8.Omm, and more preferably in a range from l.Omm to S.Omm. The foamable material preferably is a mixture of polyo:ls and isocyanate so as to form the midsole 40 of polyurethane.
The mold 100 is preferably operated at a molding temperature in a range of from 40 to 120°C for forming the midsole 40 of polyurethane with the cover sheet 21 made from ethylene vinylacetate copolymer. The inner wall 101 of the mold 100 can be patterned so that when the cover sheet 21 is p~:essed against and is heated by the mold 100 upon foaming of the foamable material in the mold 100, the cover sheet 21 can be patterned as well. Since the cover ;sheet 21 is pressed S against the inner wall 101 of the mold 100, the pattern formed on the cover sheet 21 can precisely conform to that of the inner wall 101 of the mold 100.
Preferably, an inert gas is filled into the inner cavity 90 prior to the injection of the foamable material into the inner cavity 90 so as to enhance the pressing of the cover sheet 21 against the inner wall 101 of the mold 100 during the forming of the midsole 40 in the inner cavity 90.
The method of this invention can further include a step of loading a filler 45 (see Fig. 6) in the inner cavity 90 before placing the assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 so that the filler 45 will be embedded in the midsole 40 after formation of t:he midsole 40. The filler 45 can be in the form of pellets; and can be made of a plastic material selected from a group consisting of ethylene vinylacetate copolymer, rubber, and polyurethane.
Referring now to Fig . 7 , in combination with Fig .
6, the method of this invention can further include a step of disposing a plurality of cushioning pads 50, such as air bag units, in the inner cavity 90 before placing the assembly of the outsole 2 0 , the upper 3 0 , and the cover sheet 21 in the mold cavity 102 so that the cushioning pads 50 can be embedded in the midsole 40 after formation of the midsole 40. Each cushioning pad 50 can have extensions 51 extending through the cover sheet 21 so as to be exposed from the cover sheet 21. As such, the inner wall 101 of the mold 100 is provided with positioning holes 10:3 for receiving the extensions 51 during the formation of the midsole 40.
Preferably, the extensions 51 a re provided with sleeves 62 which are received in the positioning holes 103 during the formation of the midsole 40.
Thefollowing Examples illustrate the advantage of using the cover sheet 21 according to the method of this invention.
Example 1 Material of the cover sheet: ethylene vinylacetate copolymer.
Thiclmess of the cover sheet: 2.0 mm.
Shape of the inner wall of the nbld: concave with shallow pattern.
Foamable material: polyols and isocyanate Arr~unt of the foarnable material: 133 grams.
Molding temperature: 50~C.
Molding time: '7 minutes.
Result: Density of the midsole is 0.:34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 2 Material of the cover sheet: ethylenevinylacetate copolymer.
Thicl~ess of the cover sheet: 5.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature: 70°C.
Molding time: '7 minutes.
Result: Density of the midsole is 0.:34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 3 Material of the cover sheet : ethylene vinylacetate copolymer.
Thicl~.ess of the cover sheet: 8.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature: 120°C.
Molding time: S minutes.
Result: Density of the rnidsole is 0.34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
Example 4 Material of the cover sheet: ethylene vinylacetate copolymer.
Thicl~.ess of the cover sheet: 5.0 mm.
Shape of the inner wall of the mold: concave with shallow pattern.
Foamable material: polyols and isocyanate Amount of the foamable material: 133 grams.
Molding temperature : 12 0 °C .
Molding time: 5 minutes.
Result: Density of the midsole is 0.34 g/cm3, profile of the cover sheet is consistent with that of the inner wall of the mold, clear pattern is formed on the cover sheet, and no flash is formed on the seam between the cover sheet and the upper.
The inventor of this application found that when the thickness of the cover sheet of ethylene vinylacetate copolymer is less than 0.5 mm and the molding temperature is above room temperature, the cover sheet tends to break, which leads to the formation of flash on the seam between the cover sheet and the upper, and that when the thickness of the cover sheet of ethylene vinylacetate copolymer is greater than 9 . Omm; the cover sheet is dif f icult to be shaped during the molding process even at a molding temperature of about 120°C. Moreover, when molding proceeds at room temperature, poor~profile of and obscure pattern on the cover sheet of ethylene vinylacetate copolymer result dueto poorflexibility of the ethylene vinylacetate copolymer under room temperature. The drawback can be overcome by using polyurethane film as the cover sheet, which is relatively soft and flexible under room temperature.
Figs. 8 to 10 illustrate how a sandal is made according to the method of this invention. The sandal includes an outsole 20' , an upper 30' with an upper flange 21' disposed over and connected to the out sole 20' , a midsole 40' formed according to the method of this invention and enclosed by th.e outsole 20' and the upper 30' , and a strap unit 31' having four end portions 32'. The function of the upper flange 21' is similar to that of the cover sheet 21 shown in Fig. 4.
The outsole 20' is provided with a pair of linking straps 24' having end portions which are stitched onto the end portions 32' of the strap unit 31' . The upper 30' is formed with four slits 411' for passage of the end portions of the linking straps 24' .
Before the formation of the midsole 40', the upper 30' and the outsole 20' are respectively mounted on the upper mold part 111' and the bottom mold part 112' , and four positioning sleeves 26' and four support sleeves 25' are provided and are disposed in a manner that the four positioning sleeves 26' extend through the upper mold part 111' and respectively into the slits 411', that the four support sleeves 25' are disposed between the outsole 20' and the upper 30' at the slits 411' and respectively receive the end portions of the linking straps 24' , and that the end portions of the linking straps 24' extend outwardly of the upper mold part 111' through the positioning sleeves 26' . After the formation of the midsole 40' , the positioning sleeves 26' can be removed from the upper mold part 111', and the end portions of the linking straps 24' can be stitched onto the end portions 32' of the strap unit 31' after removal of the upper and bottom mold parts 111' , 112' . It is noted that the end portions 32' of the strap unit 31' can be stitched onto the end portions of the linking straps 24' and the thus formed assembly is then disposed in the mold cavity 90' for subsequent processing steps for the formation of the midsole 40' .
By using the cover sheet 21 according to the method of this invention, the aforesaid drawbacks as encountered in the prior art can be eliminated.
With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention. It is therefore intended that the invention be limited only as recited in the appended claims.
Claims (9)
1. A method for making a footwear, comprising the steps of:
preparing an outsole having a peripheral side wall;
preparing an upper that is vertically aligned with and that is spaced apart from said outsole and that has a peripheral side wall;
preparing a flexible elongated cover sheet that is disposed between and that interconnects said peripheral side walls of said outsole and said upper so as to confine an inner cavity among said outsole, said upper, and said cover sheet, said cover sheet being expandable outwardly of said inner cavity when an inner pressure in said inner cavity is increased;
preparing a mold that has an inner wall defining a mold cavity, an upper mold part with a last, a bottom mold part opposite to said upper mold part, and at least two opposite side mold parts;
placing an assembly of said outsole, said upper, and said cover sheet in said mold cavity such that said outsole is mounted on said bottom mold part, that said upper is fittingly sleeved on said last, and that said cover sheet confronts said side mold parts; and filling a foamable material into said inner cavity and permitting curing and expansion of said foamable material to take place and to form a midsole bonded to said upper, said outsole, and said cover sheet, which, in turn, increases the inner pressure in said inner cavity to result in expansion of said cover sheet, and which permits said cover sheet to press against said inner wall of said mold and to form into a shape that conforms to said inner wall of said mold.
preparing an outsole having a peripheral side wall;
preparing an upper that is vertically aligned with and that is spaced apart from said outsole and that has a peripheral side wall;
preparing a flexible elongated cover sheet that is disposed between and that interconnects said peripheral side walls of said outsole and said upper so as to confine an inner cavity among said outsole, said upper, and said cover sheet, said cover sheet being expandable outwardly of said inner cavity when an inner pressure in said inner cavity is increased;
preparing a mold that has an inner wall defining a mold cavity, an upper mold part with a last, a bottom mold part opposite to said upper mold part, and at least two opposite side mold parts;
placing an assembly of said outsole, said upper, and said cover sheet in said mold cavity such that said outsole is mounted on said bottom mold part, that said upper is fittingly sleeved on said last, and that said cover sheet confronts said side mold parts; and filling a foamable material into said inner cavity and permitting curing and expansion of said foamable material to take place and to form a midsole bonded to said upper, said outsole, and said cover sheet, which, in turn, increases the inner pressure in said inner cavity to result in expansion of said cover sheet, and which permits said cover sheet to press against said inner wall of said mold and to form into a shape that conforms to said inner wall of said mold.
2. The method of Claim 1, wherein said cover sheet is made from ethylene vinylacetate copolymer.
3. The method of Claim 2, wherein said cover sheet has a thickness in a range of from 0.5mm to 8.0mm.
4. The method of Claim 3, further comprising the step of heating said mold to a molding temperature in a range of from 40 °C to 120 °C.
5. The method of Claim 1, further comprising the step of filling a gas into said inner cavity so as to increase the inner pressure in said inner cavity before the step of filling said foamable material into said inner cavity, thereby enhancing the pressing of said cover sheet against said inner wall of said mold during the forming of said midsole in said inner cavity.
6. The method of Claim 1, wherein said cover sheet is made from ethylene vinylacetate copolymer, and said midsole is made of polyurethane.
7. The method of Claim 1, further comprising the step of loading a filler in said inner cavity before the formation of said midsole.
8. The method of Claim 1, further comprising the step of disposing a plurality of cushioning pads in said inner cavity before the formation of said midsole.
9. The method of Claim 8, wherein each of said cushioning pads is an air bag unit.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002377082A CA2377082C (en) | 2002-03-15 | 2002-03-15 | Method for making a footwear having a midsole surrounded by a cover sheet |
| JP2002112272A JP2003304908A (en) | 2002-03-15 | 2002-04-15 | Producing method of shoe with foamed midsole |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002377082A CA2377082C (en) | 2002-03-15 | 2002-03-15 | Method for making a footwear having a midsole surrounded by a cover sheet |
| JP2002112272A JP2003304908A (en) | 2002-03-15 | 2002-04-15 | Producing method of shoe with foamed midsole |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2377082A1 CA2377082A1 (en) | 2003-09-15 |
| CA2377082C true CA2377082C (en) | 2005-05-24 |
Family
ID=32313418
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002377082A Expired - Fee Related CA2377082C (en) | 2002-03-15 | 2002-03-15 | Method for making a footwear having a midsole surrounded by a cover sheet |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2003304908A (en) |
| CA (1) | CA2377082C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1902269B (en) * | 2004-01-06 | 2010-09-15 | 巴斯福股份公司 | Method for the production of shoes |
| CN104886876A (en) * | 2015-03-11 | 2015-09-09 | 江文宏 | Plastic shoe material setting method and device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3711919B1 (en) * | 2019-03-19 | 2021-01-06 | DESMA Schuhmaschinen GmbH | Method and system for manufacturing a shoe sole with a foil applied to the lateral surface of the sole |
-
2002
- 2002-03-15 CA CA002377082A patent/CA2377082C/en not_active Expired - Fee Related
- 2002-04-15 JP JP2002112272A patent/JP2003304908A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1902269B (en) * | 2004-01-06 | 2010-09-15 | 巴斯福股份公司 | Method for the production of shoes |
| CN104886876A (en) * | 2015-03-11 | 2015-09-09 | 江文宏 | Plastic shoe material setting method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2377082A1 (en) | 2003-09-15 |
| JP2003304908A (en) | 2003-10-28 |
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| EEER | Examination request | ||
| MKLA | Lapsed |