EP0553071B1

EP0553071B1 - Method for manufacturing moulded footwear in different widths

Info

Publication number: EP0553071B1
Application number: EP90915275A
Authority: EP
Inventors: Icaro Olivieri; René Bourque
Original assignee: Canstar Sports Group Inc
Current assignee: Canstar Sports Group Inc
Priority date: 1990-10-19
Filing date: 1990-10-19
Publication date: 1995-04-05
Anticipated expiration: 2010-10-19
Also published as: WO1992006607A1; EP0553071A1; DE69018485D1; FI931669A0; DE69018485T2; FI931669A; CA2092550A1

Abstract

The present invention relates to a method for manufacturing moulded footwear to a desired width, the method comprising the steps of moulding the structure of a footwear having an upper portion, a lower portion and a sole with a thermoplastic material; of providing the sole of the footwear with a weakened area so as to allow some lateral displacement of the lower portion and finally, of forcing the lower portion of said footwear over a width adjusting means to adjust the lower portion of the moulded footwear to said desired width.

Description

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 (Paquet) 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 process. This design allows different widths by stitching together pieces of material of different lengths over the last. This produces what we call the "upper".
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. FR-A-2 348 665 also shows a method to reshape a complete preformed moulded boot to an individual's foot, the method having similar drawbacks as referred to above.

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.
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.
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.

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, 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, 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 only the 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.
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 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.

LIST OF ELEMENTS

10: Moulded footwear holes
15: Insole
20: Last
25: Thinner sole
30: Sole section
35: Front section
40: Heel section
42: Bottom portion of the moulded boot
45: Weakened area
50a & 50b: Openings
55: Flange
60: Nails
65: Finishing sole
70: Thin sole
75: Last with vacuum holes
76: Oven
80: Vacuum holes
75: Last with vacuum
80: Vacuum holes
85: Channel
86: Lower portion of the moulded boot
90: Metal last
95: Mould
100: Lasted footwear
105: Cavity structure
110: Bottom plate
115: Side plate
120: Side plate
125: Inwardly surface
130: Cavity
135: Lower portion
140: Finished product
145: Finished product

Claims

A method for manufacturing moulded footwear having a lover 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 (45) so as to allow lateral movement of the said lower portion;

- forcing the lower portion of said footwear over a width adjusting means (20) so as to conform the lower portion of said moulded footwear to the width of said adjusting means;

- attaching a finishing sole (65) to said sole portion.
A method as described in claim 1, further comprising the step of applying sufficient heat to said sole portion of said footwear to allow the thermoplastic material to become moldable.
A method according to claim 2, wherein the width adjusting means comprises a last (20).
A method according to claim 3, wherein the weakened area of the moulded footwear comprises a thin sole (70) and said last (75) is provided with a plurality of vacuum holes (80) and the method further comprises the following steps:
- applying a negative pressure to said last (75) so as to conform the heated lower portion to the shape of said last (75);

- cooling of the heated lower portion.
A method for manufacturing moulded footwear to a desired width, said footwear having a lower portion and 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 (50a, 50b) so as to allow lateral movement to the said lower portion;

- inserting a last (90) having the desired width into said moulded footwear;

- placing the combination of the last and the footwear into a mould (95) wherein the lower portion of the footwear is heated so as to force said footwear to reach the desired width;

- injecting a thermoplastic into the mould to form a finishing sole;

- cooling of the heated lover portion and finishing sole.