GB2071989A - Protective toe caps for footwear - Google Patents

Abstract

A protective or safety toe cap 10 is made of plastics material. The toe cap consists of a single moulding having a top portion 11, end wall 12, side wall 13 and a flange 14 extending inwardly around the side walls 13 at the bottom of the toe cap. The edge of the toe cap may be thinned towards its open end 17 to facilitate the formation of footwear incorporating the toe cap. A method of forming the toe cap is described and preferred materials, properties and thicknesses are specified. <IMAGE>

Description

SPECIFICATION Protective toe caps This invention relates to protective toe caps or safety toe caps.

Known protective toe caps are made of steel and they are therefore both heavy and uncomfortable to wear, particularly in cold environments, such as cold stores. They are also subject to corrosion and expensive to manufacture.

It is an object of the present invention to provide a cheaper and lighter toe cap.

From one aspect the invention consists in a protective or safety toe cap for footwear made principally of non-metallic material.

Preferably the toe cap is formed as a moulding of plastics material, for example from polycarbonate, polyvinylchloride, nylon, polypropylene or polyester. The material may be reinforced, for example, by at least one of the following; glass, limestone, talc, cellulose or carbon powder or fibres, metallic straps, sheets, powders or nets. The material, when moulded, may have Poisson's ratio in the range 0.3 to 0.44, a sheer modulus in the range of 60 x 109 to 110 x 109 N/m2, and/or a Young's modulus in the range 2 x 109 to 30 x 109 N/m2. The toe cap may have a Vickers hardness number in the range 50 to 80.

The thickness of the toe cap may be in the range 1.5 mm to 5 mm, but preferably the cap has a thickness in the range 2 mm to 3.5 mm. The thickness of the toe cap need not be uniform and thickening may occur along at least part of a line passing longitudinally through the toe end of the cap or at the join between the upper part and the side walls. Preferably at least a section of the upper part of the toe cap is thicker than the rest of the toe cap and the toe cap may be thickest at or adjacent the toe end. Conveniently the thickest part of the toe cap is between twice and four times the average thickness of the cap and the area of increased thickness may extend over between 5 per cent and 30 per cent of the total area of the toe cap.

The toe cap may further comprise an inwardly extending flange formed integrally with or connected to the lower edge of the side walls of the cap.

The flange may have a width in the range 0.5 mm to 1.5 cm.

The weight of the toe cap may lie in the range 10 x 103 and 50 x 10-3kg. The toe cap may be higher on one side than the other side and it may be thinned or chamfered adjacent its open end. The lower edges of the side walls may be interconnected by a web or base. The web or base may leave between 10 and 90 per cent of the bottom of the toe cap open.

The toe cap may pass at least one of the 40, 80, 120, 160 or 200 joule drop test defined in British Standard No. BS 953:1979. Alternatively the material, thickness, dimensions and shape of the toe cap may be such that a vertical impact of between 40 and 200 joules will not distort the upper wall of the cap by more than 20 mm.

The invention also includes an article of footwear including a toe cap as defined in any one of the preceding paragraphs..

The article may have a sole of polyvinylchloride or one made from a polyurethane/fibrous mixture material. The upper and/or the sole may be made from plastics material or leather. The article of footwear may comprise a heat insulating upper and sole and a plastics material toe cap.

In any of these cases the article may satisfy at least the mandatory requirements of British Standards Nos. BS 953:1979, BS 1870 Part 1:1979 or BS 1870 Part 2:1976 in as much as they relate to toe caps and other than any requirement that the toe cap be made of steel.

From a further aspect the invention may include a method of manufacturing a toe cap as defined above, including injection moulding the-toe cap and stress relieving the moulded toe cap.

The stress relieving may be performed by heating and/or water absorption processes. The material is preferably injected in the moulding process such that there is no material discontinuity or weakness in the upper part of the toe cap.

The invention may be performed in a number of ways, a specific embodiment of which will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a view from below of a protective toe cap; Figure 2 is a cross sectional view of the toe cap of Figure 1 along the line ll-ll; Figure 3 is a cross sectional view along the line lil-lil; and Figure 4 is a vertical section through a toe of a shoe incorporating the toe cap of Figures 1 to 3.

Figures 1 to 3 show a protective or safety toe-cap 10 made of plastics material. The toe-cap consists of a single moulding having a top portion 11, end wall 12, side walls 13 and a flange 14 extending inwardly around the side walls 13 at the bottom of the toe cap.

The top portion 11 and end wall 12 are thickened at 15 and 15a to strengthen the toe cap. The edge of the toe cap may be thinned towards its open end 17 for reasons set out below.

The flange 14 is provided to partly restrain the side wall 13 against the lateral movement which otherwise occurs when the top portion 11 receives an impact from a falling object and partly to spread the load of the impact before transmitting it to the sole.

Such lateral movement is dangerous because it causes the top portion 11 to be at least temporarily lowered under the impact. If the top portion comes into contact with the wearer's toes the force of the impact is transmitted to the toes.

In an alternative form the flange may be extended to form a web or base. However a part of the bottom is preferably open to aid force dissipation. The open portion may extend across 10 per cent to 70 per cent of the area of the bottom of the toe cap. Alternatively it may extend across 10 per cent to 90 per cent of the area of the bottom.

Alternatively the base 14 can extend across the whole of the bottom, but in this case the majority of the force of the impact must be disssipated in the toe cap 10 alone and thus the toe cap must be correspondingly stronger.

Preferably the toe cap 10 is made as a single moulding, but it will be appreciated that the web 14 could be replaced by a metal strap embedded in andfor encircling the toe cap. In this case the strap could be used to strengthen the upper part of the toe cap 10.

Preferably the plastics material of the toe cap is reinforced. Typically the reinforcing material may be glass, limestone, talc or carbon fibre, but other suitable materials may be used.

The plastics material may typically be polycarbonate, polyvinylchloride, nylon, polypropylene or polyester, but other suitable material may be used.

Preferably the toe cap passes at least one of the 40, 80, 120, 160 or 200 joule drop test defined in paragraph 4.1 to 4.5.4 of British Standard No. BS 953:1979.

The toe cap is preferably made by injection moulding. In the injection moulding process the flow rate of the material and the gate size and location are chosen so as to ensure that any moulding discontinuity or weakness does not occur in the upper portion of the toe cap. Once the moulding process is completed the toe cap is subjected to a stress relieving process such as heating or boiling. Heating may be carried out in a humidifier.

Figure 3 shows the toe of an article of footwear, such as a boot, which is generally indicated at 18.

The boot 18 comprises a sole 19 on which are mounted an insole 20 and a toe cap 21. A plastics material upper 22 is secured to at least a part of the sole and extends over the toe cap 21 encapsulating it. It will be noted that the thinning of the open end of the toe cap provides a gradual transition between the supported and unsupported sections of the upper 22. This transition prevents the edge of the toe cap 21 showing through the upper 22. Similar advantages occur when the toe cap 21 is used with a leather upper. A lining 23 extends around the inside of the boot 18. Typically the lining is made of split leather or, cloth or a synthetic material such as cambrelle.

The sole should be preferably made of a shock absorbing material such as polyvinylchloride.

Steel toe caps are subject to corrosion and thus the use of non-metallic toe caps will extend the life of the product Instead of plastics material the toe cap 10 may be made of leather or other suitable non metallic materials.

Preferably the footwear hereinbefore described satisfies at least the mandatory requirements of British Standard No. BS 953:1979 and in the case of footwear incorporating safety toe caps, of British Standards Nos. BS 1870 Part 1:1979 or BS 1870 Part 2; 1976 other than any requirement that the toe cap be made of steel.

It will be appreciated that the weight of a protective boot or other article of protective footwear having the toe cap of Figures 1 and 2 is considerably lighter than that of one including a traditional steel toe cap.

In the case of protective insulating footwear for use in cold environments the toe cap of Figures 1 and 2 is considerably more comfortable to wear because the toe cap serves to insulate the wearer's toes from the cold whereas a steel toe cap rapidly becomes cold greatly reducing the length of time the wearer can stay in that environment.

Claims (36)

1. A protective or safety toe cap for footwear made principally of non-metallic material.

2. A toe cap as claimed in claim 1, formed as a moulding in plastics material.

3. A toe cap as claimed in claim 2, wherein the material is one of polycarbonate, polyvinylchloride, nylon, polypropylene or polyester.

4. A toe cap as claimed any one of the preceding claims, wherein the material is reinforced.

5. A toe cap as claimed in claim 4, wherein the material is reinforced by at least one of the following; glass, limestone, talc, cellulose or carbon powder or fibres, metallic straps, sheets, powders or nets.

6. A toe cap as claimed in any one of the preceding claims, wherein the material, when moulded, has a Poisson's ratio in the range 0.3 to 0.44.

7. Atoe cap as claimed in any one of the preceding claims wherein the material, when moulded, has a sheer modulus in the range 60 x 109 to 110 x 109 Elm2.

8. A toe cap as claimed in any one of the preceding claims, wherein the material has a Young's modulus in the range 2 x 109 to 30 x 109 N/m2.

9. A toe cap as claimed in any one of the preceding claims, wherein the thickness of the toe cap is in the range 1.5 mm to 5 mm.

10. A toe cap as claimed in claim 9, wherein the toe cap has a thickness in the range 2 mm to 3.5 mm.

11. A toe cap as claimed in any one of the preceding claims, wherein the thickness of the toe cap is not uniform.

12. A toe cap according to claim 11, including a generally upright peripheral wall joined to a general lyhorizontal upper wall, the thickness of the cap over the major part of the upright and upper walls being less than the thickness at the join.

13. A toe cap as claimed in claim 11, wherein the toe cap is thickest on at least part of a line passing longitudinally through the toe end of the cap.

14. Atoe cap as claimed in anyone of claims 11 to 13, wherein at least a section of the upper part of the toe cap is thicker than a the rest of the toe cap.

15. A toe cap as claimed in any one of claims 11 to 14, wherein the toe cap is thickest at or adjacent the toe end.

16. A toe cap as claimed in any one of claims 11 to 15, wherein the thickest part of the toe cap is between twice and four times the average thickness of the cap.

17. Atoe cap as claimed in any one of claims 11 to 16, wherein there is an area of increased thickness which extends over between 5 per cent and 30 per cent ofthetotal area of the toe cap.

18. Atoe cap as claimed in any one ofthe preceding claims, further comprising an inwardly extending flange formed integrally with or connected to the lower edge of the side walls of the cap.

19. Atoe cap as claimed in claim 17, wherein the width of the flange is between 0.5 mm and 1.5 mm.

20. A toe cap as claimed in any one of the preceeding claims having a weight lieing in the range10x 10~3and 50 x 10-3 kg.

21. Atoe cap as claimed in any one of the preceding claims, wherein one side of the toe cap is higher than the other side.

22. A toe cap as claimed in any one of the preceding claims, wherein the toe cap is thinned or chamfered adjacent its open end.

23. Atone cap as claimed in any one of the preceding claims including a web or base interconnecting the lower edges of the side walls.

24. A toe cap as claimed in claim 22, wherein the web or base leaves between 10 per cent and 90 per cent of the bottom of the toe cap open.

25. A toe cap as claimed in any one of the preceding claims, which passes at least one of the 40,80, 120, 160 or 200 joule drop test defined in British Standard No. BS 953:1979.

25. A toe cap according to any one of the preceding claims, in which the material, its thickness, the dimensions and shape of the toe cap are such that a vertical impact in the range 40 to 200 joules will not distort the upper wall of the cap by more than 20 mm.

26. A toe cap of non metallic material substantially as hereinbefore defined with reference to the accompanying drawings.

27. A toe cap as claimed in any one of the preceding claims having a Vickers Hardness number in the range 50 to 80.

28. An article of footwear including a toe cap as claimed in any one of the preceding claims.

29. An article as claimed in claim 28 having a sole of polyvinylchloride.

30. An article as claimed in claim 28, having a sole made of a polyeurethane/fibrous material mixture.

31. An article as claimed in claim 28, wherein the upper and/or the sole are made from plastics material or leather.

32. An article of footwear comprising a heat insulating upper and sole and a plastics material toe cap.

33. An article as claimed in any one ofthe preceding claims, which satisfies at least the mandatory requirements of British Standards Nos. BS 953:1979, BS 1870 Part 1:1979 or BS 1870 Part 2:1976 in as much as they relate to toe caps and other than any requirement that the toe cap be made of steel.

34. A method of manufacturing a toe cap as claimed in any one of claims 1 to 27, comprising injection moulding the toe caps and stress relieving the moulded toe cap.

35. A method as claimed claim 34, wherein stress relieving is performed by heating and/or water absorption processes.

36. A method as claimed claim 34 or 35, wherein the material is injected in the moulding process such that there is no material discontinuity or weakness in the upper part of the toe cap.