Although it is known to stitch an upper directly to a sole, the upper is frequently stitched to a welt, which is then heat-sealed to the sole. This method is commonly used in boots and shoes sold under the"Dr. Martens" (Registered Trade Mark) label. One problem of such a construction, particularly if the stitching is visible outside the upper, is that, in extreme conditions, water can penetrate through the stitching.

An object of the present invention is to provide a method of manufacturing a boot or shoe which hinders the ingress of water at the stitching.

The invention provides a method of manufacturing a boot or shoe as claimed in Claim 1. Thus, a water-tight seal is obtained without heat treatment.

By self-amalgamating material is to be understood a material that becomes homogenous when in contact with itself, frequently, but not always, under pressure, eg modelling clay, putty. Suitable pliable, self-amalgamating, mastic sealing material for use in the method according to the present invention will be described in detail below.

The advantage of using self amalgamating material is that a waterproof/water-resistant seal is obtained without the need to apply heat to soften or melt the material providing the seal.

Although the self-amalgamating material may be applied to any stitching on the upper, it is preferably applied to the stitching adjacent the sole, ie the region most susceptible to water ingress.

Preferably, the upper is stitched to a welt which is subsequently attached to the sole, the strip being arranged between the upper and the welt. The stitching may be visible on the outer surface of the welt, or may be concealed by the welt.

The use of a welt is not essential, thus, for example the upper may be stitched to an inner sole which is subsequently heat-sealed to the sole, the strip being arranged between the upper and the inner sole. If desired. an insole may be arranged between the upper and the inner sole.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein Fig. 1 is a transverse cross-section of part of a boot or shoe manufactured by a first embodiment of the method according to the invention; Fig. 2 is a similar view to Fig. 1 manufactured by a second embodiment of the method according to the invention, Fig. 3 is a view similar to Fig. 1, but manufactured by a third embodiment according to the invention, and Fig. 4 is a similar view to Fig. 3, but manufactured by a fourth embodiment according to the invention.

In Fig. 1 a boot or shoe comprises, a sole 2, an insole 3 having a depending peripheral rib 4, a welt 5 and stitching 6. A strip 7 of pliable, self-amalgamating, mastic sealing material, is arranged between the outer surface of the upper 1 and an inner surface 8 of the welt 5. The strip 7 is first applied to the inner surface 8 of the welt 5 which is then placed around the lower peripheral edge of the upper 1. The welt 5 may be provided with the strip 7 already in place and protected by a peel-off strip, which is removed before stitching. For example, the strip 7 could be directly extruded onto the welt 5 or applied thereto by adhesive.

The insole 3 is placed on the inside of the upper and the welt 5, the strip 7, the upper 1 and rib 4 of the insole 3 are stitched together by stitching 6. The stitching 6 is not visible from outside the upper. The strip 7 of the self-amalgamating material closes and seals around the stitching 6 so as to provide a water-tight seal, and also seals the point at which the two ends (not shown) of the welt 5 meet.

Thus, a waterproof seal, which is both soft and pliable, is formed providing a water- tight joint between the welt 5 and the upper 1, thus hindering the ingress of water through the stitching 6.

A bottom surface 9 of the welt 5 is then attached to the sole 2 by any suitable method, eg by adhesive or heat welding. The sole may be formed of any suitable material, eg PVC.

The strip 7 of self-amalgamating mastic material may be formed from polyisobutylene, polythene, butyl rubber, silicon, rubber or any similar material, usually supplied in the form of a tape. Examples of suitable self-amalgamating mastic tapes as commonly used in the electrical industry, eg for insulating cable joints, electrical components etc, may be obtained for example from 3M (sold under the trade marks ADVANCE, ROTUNDA SCOTCH 23), from Rotunda plc (sold under the trade mark Rotunda 2575), from Preform Sealants Ltd, Ohio, USA (eg PS 1 Specialized Butyl Tapes), from RS Components Ltd, or from Scapa Tapes UK Limited.

The embodiment shown in Fig. 1 is known as a"Plain Welt"construction, in which the stitching is hidden; the method according to the invention may also be applied to a welt construction in which the stitching is exposed, sometimes referred to as a"Z Welt" construction, as shown in Fig. 2.

The construction shown in Fig. 2 is similar to that shown in Fig. 1 except that the stitching 6 extends substantially horizontally through the welt 5 to an outer surface 10 of the welt, whereby the stitching 6 is visible. As in Fig. 1, the strip 7 of pliable, self-amalgamating mastic sealing material, is arranged between the inner surface 8 of the welt and the outer surface of the upper 1.

In Figs. 1 and 2 the space between the insole 3 and the sole 2 preferably contains a resilient insert, eg of foam material.

In the construction shown in Fig. 3, the welt 5 has been omitted, and a through sole 11 has been arranged between the upper 1 and the sole 2 and the insole 3 is arranged between the upper 1 and the through sole 11. The lower peripheral edge of the upper 1 is turned outwardly to form a flange 11, and the insole 3 extends laterally to the outside of the shoe. The strip 7 of pliable, self-amalgamating mastic sealing material, is inserted between the flange I'of the upper 1 and the upper surface of the extended insole 3.

The flange 1'of the upper 1, the strip 7, the insole 3 and the through sole 11 are all stitched together with stitching 6, which extends substantially in the upright direction.

The through sole 11 is then attached to the sole 2 in any suitable way, eg by adhesive or heat-welding, so that the lower end of the stitching 6 is hidden and protected. The stitching 6 is only exposed at its upper end, and water ingress here is hindered by the adjacent strip 7 of self-amalgamating material.

The construction of Fig. 3 shows the typical"Dr. Martens" (Registered Trade Mark) children's construction of the PVC sole 2, which has a recess 12 accommodating an insert 13 of soft resilient material, eg foam material.

In a further prefen ed embodiment, the outer periphery of the sole 2 may be extended outwardly and upwardly as shown in broken line in Fig. 3 to enclose the peripheral edges of the through sole 11, the insole 3, the strip 7 and the flange 1'of the upper 1 to which it may be heat welded to prevent water ingress at the peripheral edges.

In the construction of Figs. 1 to 3 the peripheral surface of the sole and welt or sole and inner sole, respectively, may be grooved to provide the usual"Dr. Martens" (Registered Trade Mark) look.

The embodiment shown in Fig. 4 is similar to that of Fig. 3 and shows a typical "Moccasin"construction. Here the upper 1 is turned inwardly at the bottom and is stitched to the through sole 11 with the strip 7 of pliable, self-amalgamating, mastic sealing material therebetween. The through sole 11 is then attached to the sole 2, eg by adhesive or heat welding. The sole 2 may contain a foam insert, as shown in Fig. 3.