FIELD OF THE PRESENT INVENTION

The present invention relates to a method for manufacturing moulded footwear in different widths.

DESCRIPTION OF PRIOR ART

Skate and boot widths are handled differently in different markets. In the ski and moulded skate market, boots are made with a larger or average width. In the ski industry, many devices are available to accommodate the fit of a boot to feet of different widths such as screw adjusted devices.

However, in the hockey industry, width is adjusted only through different thicknesses of an inside liner. Thus, the segment of the population most affected with respect to performance are those people possessing narrow feet since a plurality of layers of liner must be added to the footwear.

U.S. patent no. 4,353,173 (Paguet) is an illustration of insoles for skate boots. In this particular embodiment, the insole is secured to a conventional last and the boot upper is finally mounted to same.

For the stitched boot, different widths are signified by the following symbols: B-C-D-E-EE. To be able to produce these different widths, a last design must be incorporated into the manufacturing proceiss. This design allows different widths by stitching together pieces of material of different lengths over the last. This produces what we call the "upper* ¹ .

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One example of method available is found in U.S. patent no. 3,613,271 (Geller) , in which it is shown a method to reshape a preformed molded boot to an individual's foot. Despite the fact that this type of method provides adequate fittings, it has certain drawbacks. The main drawback is that, since the temperature required to soften the thermoplastic material is kept relatively low for obvious reasons, the reshaped boot has the tendency to take back its initial shape. Furthermore, this method is time consuming and is thus not easily available on a large basis.

SUMMARY OF THE PRESENT INVENTION

The present invention relates to a method of manufacturing moulded skate and ski boots having different widths.

The process in accordance to the present invention is the manufacture of a thermoplastic moulded footwear (upper) made using the injection moulding method. The upper is made in one piece with the bottom portion having a flange all around and a transverse strap or the like joining the flanges. The idea is to provide the upper and more particularly, the lower portion of same with a weakened area so as to help the thermoforming, therefore a sole with a thin section can be used. The material used is of a thermoplastic elastomer type, which has a specific elasticity and, most importantly, has a thermoforming capability.

The thermoforming process consists of heating the thermoplastic material forming ; the upper to an optimal point of malleability and then cooling it once it has taken on the desired shape.

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Based on this thermoforming process, a boot with a semi open sole (upper) is placed in an oven until the desired malleability is reached. The upper is then slipped onto a metal form (last) possessing the dimensions and width desired. In cooling, the upper takes on the shape of the metal form and, at demoulding, the boot (upper) will have the desired width.

A method for manufacturing moulded footwear having a lower portion and a sole portion to a desired width, said footwear having a sole portion, said method comprising the following steps:

- moulding the structure of said footwear with a thermoplastic material;

providing said sole portion with a weakened area so as to allow lateral movement of the said lower portion;

- forcing the lower portion of said footwear over a width adjusting means so as to conform the lower portion of said moulded footwear to the width of said adjusting means;

- attaching a finishing sole to said sole portion.

OBJECTS OF THE PRESENT INVENTION

It is an object of the present invention to provide a method which will allow the adjustment of a moulded boot to a desired width before the sole is attached thereto.

Another object of the present invention is to provide a moulded boot which will not have the drawbacks of prior art.

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Still another object of the present invention is to provide such a method to adjust to width of a moulded boot, which is economical to use.

Yet another object of the present invention is to provide a method which can easily be adapted to large scale manufacturing.

DESCRIPTION OF DRAWINGS

The foregoing and other objects, characteristics and advantages of the present invention will be more clearly understood from the following detailed description thereof when read in conjunction with the accompanying drawings, in which:

Figures 1 to 7 show the manufacturing process in accordance with a first embodiment of the present invention.

Figures 8 to 11 show the manufacturing method in accordance with a second embodiment of the present invention.

Figures 12 to 14 show the manufacturing method in accordance with a third embodiment of the present invention.

Figure 15 shows examples of the final products.

DESCRIPTION OF A PREFERRED EMBODIMENT

The present invention will be described by means of three (3) embodiments.

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FIRST EMBODIMENT

With reference to figures 1 to 8, the basic elements of the first embodiment are: an already moulded boot 10 (made according to a conventional manufacturing process) , an insole 15, also already moulded or die cut to the desired width by conventional manufacturing processes and finally, a last diagrammatically indicated by reference numeral 20.

More precisely, the moulded boot 10 is provided with a thinned inner area 25 as shown in figure 2 to receive the insole 15 as it will be described hereinafter. The moulded boot 10 is preferably made in one piece and with a thermoplastic material of the elastomeric type which has a specific elasticity and, most importantly, a thermoforming capability.

The insole 15 may also be made of a thermoplastic material. The sole section 30, the front section 35 and the heel section 40 of the insole 15 are designed to define a specific front and heel width. Such insoles of varying widths are much less costly to produce than corresponding boot uppers.

As shown in figure 3, the bottom portion 42 of the moulded boot is provided with a "weakened area" 45 so as to allow lateral movement as it is necessary in accordance to the present invention and as it will be appreciated hereinafter. In this embodiment, the weakened area 45 comprises two openings 50a and 50b separated by a flange 55. The openings 50a and 50b, and the flange 55 are obtained during the manufacturing process of the moulded boot.

It is to be understood that the purpose of the weakened area is to allow movement of the lower portion of the moulded boot 10 so as to adjust the width of same.

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therefore any other type of means can be used for the same result. For example, the bottom portion 42 can be provided with more than two openings and alternatively, the bottom portion 42 may comprise a thinner walled section.

As shown in figure 5, the first step of the manufacturing process is to position the preformed insole 15 and the moulded boot 10 over the last 20. Then, the moulded boot 10 is stretched to fit snugly over the insole.

With reference to figure 6, a side lasting machine (not shown) is used to push the moulded boot 10 against the last 20 to shape the contour and at the same time, nails 60 or other equivalent fixation means are provided on the periphery of the bottom portion 42 of the moulded boot 10.

Finally, a finishing sole 65 is affixed to the bottom portion 42 of the moulded boot. Thermo-glue (not shown) is applied on the bottom portion, preferably said glue should be applied to both surfaces. Thereafter, the glue is reactivated under heat and the boot 10 and the finishing sole 65 are pressed together.

The process described above is mainly used to adjust the moulded boot to a width larger than what has been originally moulded since the boot 10 and the insole 15 are stretched over the last 20. However, the two other methods described hereinafter are used to adjust the moulded boot 10 to a width smaller that what has been originally moulded.

SECOND EMBODIMENT

Now, with reference to figures 8 to 11, the second embodiment of the manufacturing method is shown, wherein 10 is the pre-moulded boot and 70 represents the thin walled bottom or sole portion. In this particular embodiment.

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since a negative pressure is applied to formfit the boot as it will be appreciated hereinafter, the openings 50a and 50b of the first embodiment are not adequate.

The second embodiment uses the following elements, that is the moulded boot 10 and a last 75 provided with a plurality of vacuum holes 80 connected to a channel 85 and to a vacuum pump (not shown) .

The first step of this second embodiment, as shown in figure 8, is to place the moulded boot 10 over the last 75. The combination moulded boot and the last (lasted boot) (Figure 9a) is heated to soften the lower portion 86 of the boot. This heating can be done, for example, by placing the lasted boot in an oven 76 such that onlythe bottom and the sides of the boot 86 are heated (Figure 9b, cross section) . Subsequent to heating, pressure, by means of a vacuum pump (not shown) connected to 85, is applied so as to force the hot thermoplastic of the lower portion 86 to take the configuration of the last 75 (Figure 10) .

To reinforce the boot 10, a finishing sole 65 is affixed to the boot by using the same method as previously described in the first embodiment (Figure 11) .

THIRD EMBODIMENT

Finally, the last manufacturing method hereinafter described is also useful and is considered the preferred embodiment of the present invention. For this third method, illustrated in Figures 12 to 14, different metal lasts, generally referred as number 90, each having a specific width are used with a mould 95. The moulded boot 10 used for this embodiment is .'identical to the one used for the first embodiment, that is, provided with a weakened area such as openings 50a and 50b or having other openings.

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The moulded boot 10 is placed over the last 90 in a snugly- fit fashion (lasted boot) and the lasted boot 100 is placed with its sole surface facing downwards in order to be positioned in a sole mould 95 as shown in figures 13 and 14 (cross section) .

The basic elements of the footwear sole mould 95 are a cavity structure 105, the latter essentially consisting of a bottom plate 110 and a pair of complementary side plates 115 and 120. The side plates 115 and 120 are arranged for horizontal reciprocal movement toward and away from each other, as indicated by the arrow B. The bottom plate 110 and the last 90 is arranged for vertical reciprocal movement, as indicated by the arrow C. The inwardly directed surface 125 of the side plates 115 and 120 are contoured so as to define, when the latter is in the illustrated positions thereof, the side walls of a cavity 130, the dimensions, width and shape of which are those of the moulded boot to be obtained. Suitable heating means (not shown) are preferably provided in or in association with the cavity structure 130 and/or the last 90. It is important to mention that the heating of the footwear 10 should be limited to the lower portion 135 of said moulded boot 10.

When the lasted boot is well positioned in the mould 95, heat is applied to the mould 95 or as mentioned above, heat can be applied to the last 90, in its lower portion thereof, the last and/or the mould are usually made of metal to permit the best heat transmission. Depending of the nature of the thermoplastic material of the footwear, a specific heating time is chosen to obtain an optimal point of malleability. When this point is achieved, the mould 95 and the last 90 will dictate the width of the boot and once said boot has taken the desired shape, plastic is injected therein to form the sole of the boot. The mould is then cooled and the boot demoulded. Throughout this

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thermoforming process, the molecular structure of the elastomeric material is altered under heat but sets up at the room temperature. Figure 15 shows examples of the finished products 140 and 145.

It should be understood that various modifications, changes and variations may be made in the arrangements, operations and details of construction of the elements disclosed herein without departing from the spirit and scope of this invention. Thus, although the invention has so far been described as applying to the skate boot industry, the principles herein disclosed are applicable as well to the manufacturing process of such items as ski boots or other moulded footwear.

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LIST OF ELEMENTS

10 Moulded footwear 75 Last with vacuum holes

15 Insole 80 Vacuum holes

20 Last 85 Channel 25 Thinner sole 86 Lower portion of the

30 Sole section moulded boot

35 Front section 90 Metal last

40 Heel section 95 ^' Mould

42 Bottom portion of the 100 Lasted footwear moulded boot 105 Cavity structure

45 Weakened area 110 Bottom plate

50a & 50b Openings 115 Side plate

55 Flange 120 Side plate

60 Nails 125 Inwardly surface 65 Finishing sole 130 Cavity

70 Thin sole 135 Lower portion

75 Last with vacuum holes 140 Finished product

76 Oven 145 Finished product

80 Vacuum holes

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