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1. (WO1991006230) A METHOD OF SHAPING AND A SERIES OF SHAPING IMPLEMENTS FOR SLALOM BOOTS
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A METHOD OF SHAPING AND A SERIES OF SHAPING IMPLEMENTS FOR SLALOM BOOTS

The object of the invention is a method of shaping and a series of shaping implements for slalom boots, in which the slalom boot consists of an outer shell made form hard plastic and an inner boot made from flexible material.

A slalom boot should transfer the movements of the foot precisely as a force directed at the ski. On the other hand, a slalom boot should fit the individual foot of the user without any feeling of cramping. In accordance with the known technique it is as such possible to shape a boot entirely in accordance with the user's foot by first choosing a large outer shell and by fitting the inner boot to the shape of the user's foot with the aid of urethane foam. Operationally a boot of this kind is not, however, optimal, because the excessive flexibility of the inner boot reduces the technical operation of the boot.

In certain slalom boot models there are adjustments to alter the height of the arch of the foot and to tilt the ankle to a limited amount to a desired angle. In any event the boot is not a perfect fit for most users and it is generally believed that a slight cramping by the boot is normal.

Because the costs of the forms used in the manufacture of the outer shell are high, it is not possible to manufacture even different shapes in the same model and size. On the other hand even this would not be sufficient, because there is such an immense number of combinations of different anatomical properties that a solution of this kind is not possible.

A slalom boot and implements to shape it locally in accordance with the user's foot are shown in patent publication US 3,419,974. According to this a piece to be heated is pressed outwards from inside the shell of the boot. In practice shaping of a boot with an implement of this kind is rather limited unless high temperatures are used in heating it, which may then damage the plastic material of the boot. The grades of plastic used at present in boots stick easily to the heating head. On the other hand the publication gives no hint as to how the anatomical form of the foot is transferred to the inside of the boot in the form of directions for shaping.

It is the intention of this invention to create a method of shaping and a series of shaping implements for slalom boots, by means of which a foot with nearly arbitrary properties can be fitted to existing slalom boots. The characteristic features of the shaping method in accordance with the invention are presented in Patent Claim 1 and the characteristics of a series of implements developed to realize this are presented in Patent Claim 4. From the point of view of the invention it is essential that it makes it possible to select a boot of the correct length, after which the outer shell of the boot is given a shape fitting the foot. The shaping is most advantageously carried out with the aid of hydraulic pressing devices, in which wooden pressing heads are used. A wooden pressing head does not adhere to the plastic material, which would hinder the shaping. Other advantages and forms of application of the invention appear later.

In what follows the invention is illustrated with the aid of the accompanying figures, which show one form of application of the invention and an advantageous series of implements.

Figure 1 shows a pattern made in accordance with a foot and in addition the correction of a boot being carried out in accordance with this.
Figure 2 shows a pressing head and corresponding pressing device intended to shape the heel.
Figure 3 shows the principal components of the series of shaping implements.
Figure 4 shows the hydraulic jack unit seen from the side. Figure 5 shows a third pressing device.
Figure 6 shows a cross-section of the pressing device in Figure

5.

The slalom boot consists of a hard plastic outer shell 1 and an inner boot made of flexible material. In Figure 1 the outer boot is cut above the sole and the hydraulic pressing device 5 is placed inside the boot. The hydraulic pressing device 5 includes a pressing head 9 made from birch wood, which forms the desired protrusion.

The shaping of the boot begins, however, with the measuring of the foot. The length of the foot principally determines the initial blank to be selected, which consists of an industrially manufactured slalom boot. In addition to the length of the foot its shape is also recorded by the pattern 2, which generally will not fit into a boot of the correct length. A cut 3 is made in the cardboard pattern 2, by means of which it can easily be bent to such an angle that it fits inside the outer shell 1 of the boot to be shaped. The places to be shaped can then by easily located.

The place to be shaped is heated with a hot-air blower from both inside and out, when the plastic material softens, which makes it possible to shape it. With the aid of the hydraulic pressing device 5 the heated place is pressing by means of the wooden pressing head 9, when a protrusion is created. After this the pattern 2 is once again compared with the shaped outer shell. It may require several shapings before the pattern fits the selected boot.

In addition to the individual sole profile there may be higher individual features in the foot. Among other things the ankle bones require there own corresponding protrusion in the outer shell .

A special device, shown in Figure 2, has been developed for broadening the heel. A pressing pair 10, which is spread with the aid of hydraulic pressing device 6, is made from birch wood. Otherwise the shaping takes place as above.

By means of the series of implements shown in Figure 3 it is possible to make most of the protrusions required in the outer shells of slalom boots. A series of this kind includes a hot-air blower 4, a hydraulic pump unit 13, pressing devices 5, 6, 7, and pressing heads 9 adapted to them. The pressing heads 9 are made from birch or other hard wooden material. Birch wood has been shown to be especially well suited to this purpose, because it is sufficiently hard and on the other hand it does not adhere to the heated plastic.

The pump unit 13 consists of a pump cylinder 12, Figure 4, operated with the aid of lever 11, valve 15 to direct the pressurized oil to one of the two exit connections 14, to which the pressing devices 5, 6, 7 are connected. The pump unit 13 includes in addition an oil reservoir, and counter and shut-off valves.

If the pressing devices in accordance with Figures 5 and 6 are used, the place being shaped is determined in accordance with the heating point. Here the pressing device 8 includes two plates 16, 17 set a distance apart and a flexible bag 18 placed between them, which when compressed pushes the wooden pressing heads 20 set in the outer ring outwards against the inner wall of the boot. The pressing heads 20 are connected to each other by means of the spiral spring 21 threaded through them. Pressurized oil is fed to bag 18 through connection 19. The pressure is equally great in all directions, but a change in shape takes place only at the point of the external heating.

The shaping in accordance with the above is naturally carried out separately on each boot, from the measurement of the foot to the shaping of the boot.