GB2037217A

GB2037217A - Method of making boot with shaped shaft

Info

Publication number: GB2037217A
Application number: GB7932844A
Authority: GB
Original assignee: Wright & Co Ltd F
Current assignee: Wright & Co Ltd F
Priority date: 1978-09-29
Filing date: 1979-09-21
Publication date: 1980-07-09
Also published as: ZA795050B; FR2437174A1; GB2037217B; AU5118879A; DE2939131A1

Abstract

The foot of the boot is of conventional construction but the shaft of the boot is made of thermoplastic sheet which is stretched on a form and heated to shape the shaft. After stitching of the cut thermoplastic sheet to the leather upper, a last piece 18 is inserted in the toe and a split boot-tree consisting of parts 16 and 17 is placed in the shaft. A slider 20 running in a groove in part 17 has wedges 21 which engage cam blocks 22 and force parts 16 and 17 apart to stretch the shaft while it is heated. Alternatively, the shaft may be shaped before being attached to the rest of the boot. <IMAGE>

Description

SPECIFICATION Method of making boot with shaped shaft The present invention relates to boots with a shaped shaft, for example riding boots which have a shaft shaped to fit the leg of the wearer and fashion ankle boots which have a shaft shaped to give a special appearance to the boot.

Commonly the boot will have a foot portion with the upper extending to a region below the ankle and the shaft will be joined to the upper in the said region. The invention is, however, equally applicable when the shaft is joined to the foot portion at a different position.

At present riding boots are made in leather and the shaping of the shaft to fit the leg is a skilled craft operation which adds substantially to the cost of manufacture.

In accordance with the invention there is provided a method of making a boot with a shaped shaft wherein the shaft is made from a synthetic thermoplastic sheet material which is cut to shape, assembled and fastened to the upper of the boot, and the shaft is subjected to heat treatment while stretched on a form to cause the material to adopt the shape of the form.

The cutting and assembly of the thermoplastic sheet material may create an approximation to the required final shape of the shaft. Any wrinkling or rucking of the material which occurs during assembly is smoothed out by the heat treatment and thereafter the material tends always to return to its new shape. The details of the heat treatment will vary according to the materials employed but essentially it consists in heating the material to soften it, allowing it to remain at high temperature for a period until all stress has been relieved, and then cooling. This replaces the traditional hand-shaping or machine-shaping of a leather shaft and is clearly much simpler and cheaper. The shape will be retained and this obviates the need for boot trees.

The synthetic thermoplastic sheet material may be reinforced or laminated with textile materials provided that these do not prevent the shaping of the sheet when softened by heat.

Conveniently the whole of the boot undergoes the heat treatment together with the last and the form.

The latter may be inserted before or after assembly of the shaft, which may be made in one or more pieces.

The invention will be described in more detail with the aid of an example illistrated in the accompanying drawings, in which Figure 1 is a side view, Figure 2 is a back view of a shaped leg boot made in accordance with the invention, Figure 3 is an exploded view of the last and form used in making the boot of Figures 1 and 2, Figure 4 shows the last and form in the assembled condition, and Figure 5 is a section on the line V-V of Figure 4.

The boot shown in the drawing has a sole 10, heel 11, and upper 12 forming a foot of conventional materials and construction. Attached to this is a shaft 13 composed of a synthetic thermoplastic material.

This shaft material may be a homogeneous sheet of one material or it may be a laminated or textile reinforced material or a poromeric material. It is necessary only that it should soften when heated and thus take up a new shape readily. The shaft material is cut to shape from a flat sheet or sheets and after the completion of the foot part of the boot the shaft is stitched to the upper 12 along the seam line 14 and joined to form a back seam 15. This back seam 15 is preferably covered with a back strip. The junction between the shaft and the upper along the seam line 14 may be a two-row single or twin lap seam and the back seam may have two single rows of stitching attaching the back strap or may be stuck or welded.

The shape of the shaft is determined by a shaped form or insert which in this instance is a split boot-tree. As shown in Figure 3 to 5 this boot-tree comprises a front member 16 and a back member 17. The drawings also show a last member 18 for the forward part of the boot upper 12. As seen in Figure 5 the back member 17 has a T-section groove 19 in which is disposed a slider 20 with projecting wedgepieces 21. The wedge-pieces 21 are intended to cooperate with cam blocks 22 fixed in a groove 23 in the rear face of the front member 16. After insertion of the last member 18, front member 16 and back member 17 into the assembled boot the slider 20 is driven downwards so that the wedge pieces 21 ride over the cam blocks 22 and force the members 16 and 17 apart. In this way the last member 18 is pushed into the toe of the boot and the shaft is stretched by the members 16 and 17.

The shaft of the boot is now heated with the shaped insert in place until the thermoplastic material begins to soften and adopt the contour of the insert. It may be necessary to keep the shaft at the high temperature for a period of time to ensure that all stress is releived and the new shape is fully established. The shaft is then allowed to cool or subjected to forced air cooling, after which the shape of the shaft is permanently set and there will be a tendency for the shaft to return to this shape if deformed or damaged during use.

In one example of the process of the invention as applied to the manufacture of a riding boot a conventional boot with a lined leather upper is provided with a shaft and back strap made of black KD84"Chamolux P.V.C. code 131 supplied by Broadleys. This is a P.V.C. compound coated textile material. A top band is incorporated of matt polyurethane code C338 supplied by British United.

The whole boot, together with the last and shaft form, is raised to a temperature of 128' for 12 minutes and then cooled with air at 0'for 10 minutes.

It will be appreciated that whereas the method has been described primarily in relation to the manufacture of a riding boot, it is equally possible to produce shaped shafts whose shaping is decorative rather than functional. For example a full length "baggy" boot with a series of loose folds encircling the shaft or an ankle boot with a similar formation can be produced by use of the method of the invention.

For purposes of decoration and to strengthen the material against distortion it is possible before assembly of the shaft to mould ribs or other patterns of varying thickness on the synthetic sheet material.

Such patterning may allow the use of lighter material with resulting economies. The patterning can be applied, especially to those areas which are subject to the greatest stresses during use of the boot. In one instance, using the materials specified above, the shaft material, before assembly, had patterning applied over an area of 11.75 x 17.375 inch by means of electrically heated dies applied at a pressure of 45 Ibs. per square inch for 12 secs. at 150 C.

Whereas in the method described the shaping of the shaft is effected after it has been attached to the upper of the boot. This has the advantage that stresses created during the stitching of the shaft to the upper can be relieved during the heat treatment However it is also possible to shape the shaft before it is attached to the rest of the boot.

The shaping of the shaft after attachment to the boot is also preferred because cooperation between the front member 16 of the boot-tree and the last member 18 at their mating surfaces ensures correct orientation of the shaped shaft relative to the foot of the boot.

Claims

1. A method of making a boot with a shaped shaft wherein the shaft is made from a synthetic thermoplastic sheet material which is cut to shape, assembled and fastened to the upper of the boot and the shaft is subjected to heat tretment while stretched on a form to cause the material to adopt the shape of the form.

2. A method as claimed in claim 1 in which the shaft is fastened to the upper along a line passing below the ankle.

3. A method as claimed in claim 1 or 2 in which the shaft is assembled with a single seam running down the back of the shaft.

4. A method as claimed in any of claims 1 to 3 in which the shaft is stitched to the upper.

5. A method as claimed in any of claims 1 to 4 in which the sheet material from which the shaft is made is reinforced or laminated with a textile material.

6. A method as claimed in any of the preceding claims in which the form is composed of two parts which are forced apart by a wedge member to stretch the shaft.

7. A method as claimed in claim 6 in which the wedge member is slidable in a groove in one of the parts.

8. A boot with a shaped shaft of synthetic thermoplastic sheet material produced by the method of any one of the preceding claims.