Mold For Ski Boots And The Like

Abstract

Boot mold comprises separable outer parts and a core. Oblique strips extend downwardly from the core to the outer parts so as to form ankle-high slits at the front and back of the boot formed in the mold.

Description

SUMMARY OF THE INVENTION

This invention relates to the manufacture of molded boots and especially ski boots. It is conventional to make ski boots by molding an elastomeric material, a plastic, or a mixture of the two, in an appropriate mold. However, because of the stiffness of the material required for such boots they have the disadvantage of being difficult to flex at the level of the ankles, which impedes the skier in his movements, especially in his flexing movements, and makes his progress uncomfortable.

To overcome this disadvantage, ski boots are often made in two parts, with the upper part attached to the lower part by pivotal means at the level of the ankle bones. This construction is efficacious, but has the disadvantage of being expensive to manufacture since the molding operations have to be carried out twice, and the upper and lower parts must then be subsequently assembled.

The object of the invention is to provide a mold which eliminates these disadvantages by making it possible to produce in a single molding step a boot having an upper part which is adapted to pivot from front to back with respect to the lower part about an axis positioned approximately at the level of the tibio-carpal joint.

The invention consists of a mold of a conventional type in which the outer wall is defined by two vertical parts and a sole plate and which comprises a core, with one or more strips attached to the front and back of the core and extending obliquely to the inner surface of the two vertical parts, to which it is connected in such a manner as to produce after molding, a boot leg which slightly overlaps the foot at the back and possibly at the front, while leaving at the two sides of the boots continuous flat zones which connect the foot of the boot with the lower part of the leg and permit articulation of these two parts.

The lower part of the strips is connected to the inner surface of the vertical mold parts either directly or through a short projection carried by the two vertical mold parts and adapted to form in the boot a stop angularly limiting the pivotal movement of the leg of the boot. Alternatively, the projection carried by the vertical mold parts may have transverse grooves on those of its edges coming in contact with the strip carried by the core so as to accommodate a certain number of elastic cords connecting the upper and lower parts of the boot and serving as a draw spring.

In order that the object of the invention may be better understood, one embodiment thereof will not be described, purely by way of illustration and example, with reference to the accompanying drawings, on which:

FIG. 1 is an axial cross-section through the mold;

FIG. 2 is a transverse cross-section taken along the line II--II of FIG. 1;

FIGS. 3 and 4 show on a larger scale fragments of the boot leg utilizing two different types of connection; and

FIG. 5 shows in perspective and on an enlarged scale a fragment of the mold carrying the projection in one of the embodiments disclosed.

A conventional mold comprises two vertical parts 1 and 2 and a sole plate 3. The mold has an inner surface 4 adapted to mold the outer surface of the boot. Inside the mold is a core 5 consisting of a solid form having the volume of the inside of the boot. By injecting the plastomeric or elastomeric material 6 into the space between the core 5 and the outer parts of the mold, a boot having the desired shape is obtained in one step. However, when molding a ski boot in this manner it is necessary to use a relatively stiff material and form fairly thick walls so that the boot remains substantially inflexible and in particular does not flex in a transverse direction. It follows that the boot is difficult to flex in the longitudinal direction which is a disadvantage for this impedes the movements of the skier and in particular his flexing movements and is uncomfortable during travel.

In order to overcome this disadvantage it is common to make boots in which the upper part of the leg is molded separately from the lower part and to then assemble these two parts by means of two joints situated on opposite sides of the boot at the level of the tibio-carpal joint. This is a burdensome procedure.

In order to avoid it the invention resides in using metallic strips such as 7 and 8. Each plate is attached by its upper edge 9 to the core 5 and extends obliquely toward the bottom in the space between the core and the wall 4 so as to engage the wall at its lower edge 10.

This contact between the lower end 10 of the plate and the wall 4 may be made indirectly through a projection 11 carried by this wall, or directly against the wall as in the case of the strip 8. The strips 7 and 8 leave between themselves, on each side of the mold, a zone 12 in which there are no strips. The mold may also comprise suitable means of molding the opening in the leg at the top of the instep. In this case, the strip 8 at the front may be transversely divided into several parts to permit molding of the opening in the leg.

After opening of the mold and removal of the molding a boot is obtained which, while it is made in one piece, comprises an upper part and a lower part which are locally separated by spaced 14 corresponding to the positions of the strips 7 and 8, and possibly by a space 15 corresponding to the position of the projection 11. For example, as in the embodiment described, there may be on the back of the boot the engagement shown in FIG. 3 and, on the front, the one shown in FIG. 4. In addition to these zones of separation, the two upper and lower parts of the leg are connected by two zones corresponding to the zones 12 of the mold, which constitute a truly articulated joint.

In effect, this zone has a relatively short dimension between the front and back which permits the material, despite its thickness and stiffness, to flex so as to permit pivotal movement. During this movement the lips 16 and 17 on opposite sides of the space 14 as shown in FIG. 4 may slide upon each other, for example during forward flexing. In the same manner, the lips 18 and 19 may slide upon each other during this forward flexing. In the case of backward flexing the same thing happens. However, the effect of the movement is to reduce the width of the space 15 up until the moment at which the end 20 of the lip 18 strikes the base 21 of the lip 19. This limits the rearward articulation of the boot.

When it is desired to also limit forward flexing by means of an elastic resistance instead of a stop, the means shown on FIG. 5 may be used. This consists simply in forming in the projection 11 fixed to each vertical mold part 1 and 2 a series of slots 22 which are transversely positioned in the part of this projection at which the lower edge 10 of the blade 7 is connected to that projection. The communication thus established between the upper part and the lower part of the mold permits the formation of a certain number of strips connecting the end 20 of the lip 18 to the base 21 of the lip 19. By using an elastic material, for example an elastomer such as rubber, to make the boot, a certain elastic stretchability may be imparted to these strips so as to permit pivotal forward movement as has been hereinbefore described while elastically limiting the amplitude of this movement by providing elastic resistance thereto.

It will of course be appreciated that the embodiment which has just been described has been given purely by way of example and may be modified as to detail without thereby departing from the basic principles of the invention.

In particular it would be possible to use only one strip 7 toward the back while eliminating the strip 8, with the articulation of the front part of the boot being eliminated or otherwise provided for.

In addition to ski boots, the invention provides a means for manufacturing protective or safety boots of various types, while improving in like manner their front and backward flexing.

Claims

What is claimed is:

1. Mold for a ski boot or the like comprising two separable outer parts and a core part and characterized by the fact that it also comprises at least one strip which extends obliquely from the core part to the inner wall of an outer part with its lower edge in contact with said outer part and its upper edge in contact with the core, and one of said edges attached to the part against which it bears.

2. Mold as claimed in claim 1 in which the upper edge of the strip is attached and its lower end rests directly on the wall of the outer part.

3. Mold as claimed in claim 1 in which the upper end of the strip is attached to the core while its lower end rests on a projection from one of said outer parts.

4. Mold as claimed in claim 3 which comprises slots extending transversely through the projection against which the lower edge of the strip bears.

5. Mold as claimed in claim 1 comprising a first strip situated in a part of the mold corresponding to the back of the leg of the boot and a second strip situated in a part of the mold corresponding to the front of the leg of the boot.

6. Mold as claimed in claim 5 characterized by the fact that the strip situated at the front of the boot is divided into several parts.

7. Mold as claimed in claim 5 which comprises a plurality of said strips in the part of the mold which forms the front of the boot.

8. Mold as claimed in claim 1 comprising two strips and in which the lower edge of each strip is attached to an outer part while its upper edge rests on the core.