GB1601211A

GB1601211A - Footwear

Info

Publication number: GB1601211A
Application number: GB78677A
Authority: GB
Original assignee: Clarks Ltd
Current assignee: Clarks Ltd
Priority date: 1978-03-22
Filing date: 1978-03-22
Publication date: 1981-10-28

Description

(54) IMPROVEMENTS IN OR RELATING TO FOOTWEAR (71) We, CLARKS EXITED, a British Company, of Street, Somerset, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to footwear.

According to this invention there is provided an article of footwear having an upper with a peripheral lasting margin, an insole which extends in the toe area but not in the middle part of the length of the article, the lasting margin being inlasted to the insole where the latter extends, and a polymeric sole unit which is moulded on to the upper and insole the hanging parts 9f the lasting margin where the insole does not extend being embedded in the sole unit.

The invention also provides a method of making an article of footwear comprising the steps of forming an upper with a peripheral lasting margin, inlasting the toe region of the lasting margin of the upper to an insole which extends in the toe area but not in the middle parts of the length of the article, and moulding a polymeric sole unit on to the upper and insole, the sole unit forming an adhesive bond with the insole and the lasting margin where the insole extends and having the hanging parts of the lasting margin where the insole does not extend embedded in the sole unit.

The insole may include a heel section formed separately from the toe section and having the lasting margin in the heel region of the article inlasted thereto.

The invention will now be described in more detail with reference by way of example to the accompanying diagrammatic drawings in which: Figure 1 shows a conventional shoe in longitudinal section, Figure 2 shows in longitudinal section a shoe according to the invention, Figure 3 is a view of the underside of the shoe of Figure 2 prior to formation of the sole unit, Figure 4 is a longitudinal sectional view of another form of shoe according to the invention, Figure 5 is a view of the underside of the shoe of Figure 4 prior to formation of the sole unit, and Figure 6 shows the underside of a last used in one method according to the invention.

Referring to Figure 1 of the drawings, in a common method of making a shoe or boot, an upper 10 has its lasting margin 11 drawn under and secured to the underside of an insole 12 which covers the whole of the bottom of the inside of the shoe. Subsequently a sole unit 13 is moulded on to the underside of the lasting margin and insole.

The presence of the insole, which is relatively stiff, detracts materially from the flexibility of the finished shoe in the - area where the shoe should ideally be very flexible, namely in the middle parts of the length of the shoe, not only by reason of the insole's own stiffness but also by reason of the laminated construction which results when the sole unit is bonded directly to the insole.

This disadvantage is avoided in the construction illustrated in Figure 2. In this construction. the insole 15 extends only in the toe region of the shoe. In making the shoe a thin layer 14 of a very flexible material is temporarily secured to the bottom surface of the making last, as by pins protruding from that surface, and covers the last bottom. Adhesive may be applied to at least the parts of the thin layer 14 of material which are to contact the insole section, so as to assist in bonding the material to the insole. The back part of the shoe (with or without a stiffener) is premoulded, and the closed upper is then placed on the making last together with the insole 15. The toe portion 16 of the lasting margin of the shoe is inlasted to the insole in the manner well known to those skilled in the art. The remainder 17 of the lasting margin hangs down below the last.The lasted upper shell formed by these two operations is now transferred to a mould of the kind equipped with side closing knives, which nip the upper to the last at the feather edge. A sole unit is cast or injected directly on to the upper shell and the thin layer 14 of material covering the moulding last bottom. In so doing, the hanging portions 17 of the lasting margin become securely embedded in the sole unit 13.It will be clear that since the sole unit is cast or injected directly on to the thin layer 14 of material covering the moulding last bottom except in the toe region, the surface provided by the thin layer ~ 14 of material and the underlying top of the sole unit can by careful selection of the material of the thin layer 14 and shaping of the bottom surface of the last be shaped to correspond more accurately to the contours of the bottom of the foot than is practicable where a full insole is used. For the sake of comfort and appearance a sock is then adhesively secured to the upper surface of the layer of flexible material.

Polyurethane has been found to be a very suitable material for use in injection moulding or casting the sole unit, but any other suitable material may be employed for the purpose. However, where polyurethane is used as the material of the sole unit, some difficulty has been encountered in providing a reliable adhesive bond between the sock and the upper surface of the polyurethane sole unit and it is for this reason that the thin intermediate layer of ffexible material is provided. The thin layer of fabric separates the sock and the sole unit and is securely bonded to both.Leather, or woven or non-woven fabrics may be used for said thin layer of material and indeed any very flexible sheet material can be used which has one surface capable of forming an edhesive bond with the polyurethane during curing of the latter and to the other surface of which the sock can be securely attached by adhesive. One specific example of a material we have found particularly suitable for this purpose is a needled non-woven fabric made from man-made fibres and sold under the trade name "Aquiline" by British United Shoe Machinery Co. Ltd.

In an alternative construction illustrated in Figures 4 and 5 of the drawings, the insole comprises a toe section 20 and a heel section 21 to which the appropriate sections of the lasting margin of the upper are inlasted, but again the lasting margin in the middle parts of the length of the shoe is not secured to an insole but is embedded in the sole unit 22 moulded on to the shoe whilst the latter is on a last. Again, a thin intermediate layer 14 of a very flexible material is first temporarily secured to the bottom surface of the last.

In this case, the thin layer of sheet material is positioned on the undersurface of the last and located by pins as before, and two D-shaped insole parts are placed over it at the toe and heel ends respectively and are held on the last, each by a simple tack. Further tacks may secure the sheet material to the last in the waist region. The upper is now placed over the last and is heel-and-toe inlasted to the insole sections 20 and 21 using conventional machinery.

A sole unit is then moulded on to the lasted upper using a mould equipped with sideclosing knives as described above, and a sock is adhesively secured to the exposed surface of the thin layer of material after the shoe has been removed from the last.

An incidental advantage of the method is that, during moulding of the sole unit the thin layer of material covers the "break" of the last and prevents polyurethane from penetrating between the various sections of the last.

The use of the same last for the two purposes, i.e. making and moulding, reduces substantially the amount of labour used in the method.

A shank and/or a heel block/filler may be incorporated in the sole unit. The tank and/or filler are placed on the last bottom and held by suitable means before injection of the polyurethane into the sole mould cavity. The shank may have holes in it through which the polyurethane can pass to form a mechanical bond so as to provide additional security against movement of the shank within the sole unit.

Preferably the moulding of the sole unit is carried out with the upper shell on the original (making) last.

The last 23 may be provided with pins or studs as shown in Figure 6 for enabling the waist section of the upper to be held temporarily in place whilst the sole unit is moulded about the hanging lasting margin.

Where certain combinations of materials are employed for the upper and sole unit, it may be desirable to do additional preparatory work on the upper shell, for example grain skiving in the area to be attached to or embedded in the sole unit and possibly the application of an adhesive to the edge of the upper.

WHAT WE CLAIM IS: 1. An article of footwear having an upper with a peripheral lasting margin, an insole which extends in the toe area but not in the middle part of the length of the article, the lasting margin being inlasted to the insole where the latter extends, and a polymeric sole unit which is moulded on to the upper and insole the hanging parts of the lasting margin where the insole does not extend being embedded in the sole unit.

2. An article of footwear as claimed in claim 1, wherein the insole includes a heel section formed separately from the toe section and having the lasting margin in the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. closing knives, which nip the upper to the last at the feather edge. A sole unit is cast or injected directly on to the upper shell and the thin layer 14 of material covering the moulding last bottom. In so doing, the hanging portions 17 of the lasting margin become securely embedded in the sole unit 13. It will be clear that since the sole unit is cast or injected directly on to the thin layer 14 of material covering the moulding last bottom except in the toe region, the surface provided by the thin layer ~ 14 of material and the underlying top of the sole unit can by careful selection of the material of the thin layer 14 and shaping of the bottom surface of the last be shaped to correspond more accurately to the contours of the bottom of the foot than is practicable where a full insole is used.For the sake of comfort and appearance a sock is then adhesively secured to the upper surface of the layer of flexible material. Polyurethane has been found to be a very suitable material for use in injection moulding or casting the sole unit, but any other suitable material may be employed for the purpose. However, where polyurethane is used as the material of the sole unit, some difficulty has been encountered in providing a reliable adhesive bond between the sock and the upper surface of the polyurethane sole unit and it is for this reason that the thin intermediate layer of ffexible material is provided. The thin layer of fabric separates the sock and the sole unit and is securely bonded to both.Leather, or woven or non-woven fabrics may be used for said thin layer of material and indeed any very flexible sheet material can be used which has one surface capable of forming an edhesive bond with the polyurethane during curing of the latter and to the other surface of which the sock can be securely attached by adhesive. One specific example of a material we have found particularly suitable for this purpose is a needled non-woven fabric made from man-made fibres and sold under the trade name "Aquiline" by British United Shoe Machinery Co. Ltd. In an alternative construction illustrated in Figures 4 and 5 of the drawings, the insole comprises a toe section 20 and a heel section 21 to which the appropriate sections of the lasting margin of the upper are inlasted, but again the lasting margin in the middle parts of the length of the shoe is not secured to an insole but is embedded in the sole unit 22 moulded on to the shoe whilst the latter is on a last. Again, a thin intermediate layer 14 of a very flexible material is first temporarily secured to the bottom surface of the last. In this case, the thin layer of sheet material is positioned on the undersurface of the last and located by pins as before, and two D-shaped insole parts are placed over it at the toe and heel ends respectively and are held on the last, each by a simple tack. Further tacks may secure the sheet material to the last in the waist region. The upper is now placed over the last and is heel-and-toe inlasted to the insole sections 20 and 21 using conventional machinery. A sole unit is then moulded on to the lasted upper using a mould equipped with sideclosing knives as described above, and a sock is adhesively secured to the exposed surface of the thin layer of material after the shoe has been removed from the last. An incidental advantage of the method is that, during moulding of the sole unit the thin layer of material covers the "break" of the last and prevents polyurethane from penetrating between the various sections of the last. The use of the same last for the two purposes, i.e. making and moulding, reduces substantially the amount of labour used in the method. A shank and/or a heel block/filler may be incorporated in the sole unit. The tank and/or filler are placed on the last bottom and held by suitable means before injection of the polyurethane into the sole mould cavity. The shank may have holes in it through which the polyurethane can pass to form a mechanical bond so as to provide additional security against movement of the shank within the sole unit. Preferably the moulding of the sole unit is carried out with the upper shell on the original (making) last. The last 23 may be provided with pins or studs as shown in Figure 6 for enabling the waist section of the upper to be held temporarily in place whilst the sole unit is moulded about the hanging lasting margin. Where certain combinations of materials are employed for the upper and sole unit, it may be desirable to do additional preparatory work on the upper shell, for example grain skiving in the area to be attached to or embedded in the sole unit and possibly the application of an adhesive to the edge of the upper. WHAT WE CLAIM IS:

1. An article of footwear having an upper with a peripheral lasting margin, an insole which extends in the toe area but not in the middle part of the length of the article, the lasting margin being inlasted to the insole where the latter extends, and a polymeric sole unit which is moulded on to the upper and insole the hanging parts of the lasting margin where the insole does not extend being embedded in the sole unit.

heel region of the article inlasted thereto.

3. An article of footwear as claimed in claim 1 or claim 2, wherein a thin layer of flexible material is secured to the upper surfaces of the sole unit and insole section or sections, the material becoming bonded to the sole unit during curing of the polymeric material, and wherein a sock is adhesively secured to the upper surface of the said thin layer of flexible material.

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4. A method of making an article of foot- wear comprising the steps of forming an upper with a peripheral lasting margin, inlasting the toe region of the lasting margin of the upper to an insole which extends in the toe area but not in the middle parts of the length of the article, and moulding a polymeric sole unit on to the upper and insole, the sole unit forming an adhesive bond with the insole and the lasting margin where the insole extends and having the hanging parts of the lasting margin where the insole does not extend embedded in the sole unit.

5. A method as claimed in claim 4, wherein the polymeric sole unit is moulded on to the lasted upper whilst the upper is on a last on the bottom surface of which is first detachably secured a thin layer of flexible material which is selected to form an adhesive bond with the polymeric material of the sole unit during curing of the material, where the insole does not extend.

6. A method as claimed in claim 5, wherein the lasting of the upper to the insole is carried out on the said last after the said thin layer of flexible material has been attached to the bottom surface of the last.

7. A method as claimed in any one of claims 4 to 6, wherein the insole includes a heel section formed separately from the toe section and having the lasting margin in the heel region of the article inlasted thereto.

8. An article of footwear substantially as hereinbefore described with reference to and as illustrated in Figures 2 and 3 or in Figures 4 and 5 of the accompanying draw ings.