AU729395C - Toe and metatarsal protectors for safety footwear - Google Patents

Description

Toe and Metatarsal Protectors for Safety Footwear

Technical Field

This invention is concerned with improvements in or relating to toe and/or metatarsal protectors as used in safety footwear, namely boots and shoes that are worn in locations where there is danger of impact or compression forces being applied to and injuring the feet of the wearer.

Background Art

Many industries now require that workers wear safety footwear to protect their feet against injury caused, for example, by blows from above by falling objects, or crushing such as may be caused by a vehicle wheel rolling over the foot. Almost all safety footwear currently available comprise a toe protector, usually a steel box toe (sometimes called a toe box) providing a protective arch above the toes through which any impact or crushing force applied to its top surface is transmitted to the insole on which it rests, and through the insole to the outsole and the ground. It is a requirement for official certification (details of which are given below) that the box toe shall be incorporated into the footwear during construction and shall be an integral part of the footwear. Also, provision is now commonly made to protect the metatarsus, namely the five long bones of the instep extending from the toes to the remainder of the bones of the foot. Many of the prior proposals for metatarsal protection comprise a guard that is applied to the exterior of the boot or shoe, but increasingly the protector is incorporated into the footwear, it also being arranged to transmit any forces applied to it through the insole and outsole to the ground.

The Occupational Health & Safety Association (OHSA) specifies test and performance standards that have been established by American National Standards Inc. (ANSI) which safety footwear must pass if they are to be certified by them. The Canadian Standards Association (CSA) have adopted equivalent standards . The test procedure for impact force resistance involves dropping a standard weight on to the toe portion of a specimen boot (size 9D for men's footwear and 8B for women's footwear) at a point 2.5cm (l.Oin) from the outside tip of the toe under conditions such that it exerts a nominal impact force of specified value at a specified impact velocity. Three values of force are used, namely 101.7 Joules (75 foot pounds), 67.8 Joules (50 foot pounds), and 40.7 Joules (35 foot pounds) and footwear meeting one of these standards is certified with the designation 1/75, 1/50 or 1/35 respectively. In the crushing force test procedure the toe protector is subjected to a crushing force of l,134Kg (2,500 lbs; 11,121 Newtons) , or 795Kg (1,750 lbS; 7,784 Newtons) , or 455Kg (1,000 lbs; 4,448 Newtons), and depending upon the level of force that the footwear withstands it is certified with the designation C/75, C/50 or C/35 respectively. With both tests the boot is not certified if either of these forces depresses the toe portion so that the clearance inside is less than 1.27cm (0.5in) for a men's boot and 1.19cm (0.468in) for a women's boot.

The equivalent impact force test for a metatarsal protector (there is no compression test) requires the force to be applied at a point 8.9cm (3.5in) from the outside tip of the 9D boot toe (8.6cm or 3.375in for the 8B boot) and be of nominal value 101.7 Joules (75 foot pounds), or 67.8 Joules (50 foot pounds), or 40.7 Joules (30 foot pounds), the required minimum clearance remaining after the test being 2.5cm (l.Oin) for the 9D boot and 2.4cm (0.94in) for the 8B boot. Footwear meeting one of these standards is certified with the designation Mt/75, Mt/50 or Mt/35 respectively.

Box toes of plastics materials are available, but they are significantly thicker than the commonly used steel box toe, so that it is more difficult to incorporate them into the boot construction without the resultant boot toe appearing much more bulky, especially in side elevation. Moreover, most safety footwear is manufactured by molding the outsole to the remainder of the boot and the thicker box toe makes it impossible to use existing molds that have employed steel box toes, so that expensive new molds are required for each style of boot . Metatarsal protectors of plastics material, e.g. high density polyethylene or polypropylene (HDPE or HDPP) , ABS and various proprietary nylons, are also available and again, if the standards for impact forces are to be met, the protector is such thickness that, even if the more expensive high modulus plastics materials are used, it is difficult to incorporate in safety footwear of standard sizes. The manufacture of both box toes and metatarsal protectors from plastics material has the advantage that even if of complex shape they can be molded in a single relatively inexpensive operation. There is also the possibility that protectors that are lighter in weight can also be produced. Manufacturers of safety footwear face an inherent marketing problem that whether the footwear is supplied by the employer at cost, or with a subsidy, or whether it is purchased directly by the wearer, it is basically a product for which a relatively low purchase price is required by the customer, so that minimization of manufacturing cost is of primary importance .

Disclosure of invention

It is therefore the principal object of the invention to provide a toe protector, or a metatarsal protector, or a combination toe and metatarsal protector, that can readily be molded from plastics material and meet the test requirements for certification as described above.

It is another object to provide a toe protector, or a metatarsal protector, or a combination toe and metatarsal protector, that can be readily molded relatively inexpensively from plastics material.

It is a further object to provide a toe protector, or a metatarsal protector, or a combination toe and metatarsal protector, molded from plastics material that is able meet the test requirements for certification as described above while being sufficiently thin that it can be incorporated by molding in safety footwear using molds previously employed for steel box toes.

In accordance with the present invention there is provided a toe protector for safety footwear that comprise an upper and a sole joined to one another, the upper and sole each having respective outer and inner surfaces and having respective registering toe regions; wherein the toe protector comprises a generally U-shaped body molded from plastics material, having a top portion constituting a base of the U and two side portions constituting respective sides of the U; wherein the toe protector when incorporated into safety footwear is interposed between the upper and sole toe regions, and when so interposed has an outer surface convex toward the inner surface of the upper and an inner surface concave toward the inner surface of the sole; wherein the toe protector also comprises a force receiving part having respective upper and lower surfaces and overlying the central part of the top portion outer surface with its lower surface spaced from the said central part, the force receiving part being of concave shape toward the said central part and having two spaced junctions with the toe protector body; whereby crushing and impact forces applied to the force receiving part are operative to attempt to press the force receiving part toward the said central part of the top portion with conversion of such crushing and impact forces to corresponding longitudinal forces distributed along the junctions.

Also in accordance with the invention there is provided a metatarsal protector for safety footwear that comprise an upper and a sole joined to one another, the upper and sole each having respective outer and inner surfaces and having respective registering metatarsal regions,- wherein the metatarsal protector comprises a generally U-shaped body molded from plastics material, having a top portion constituting a base of the U and two side portions constituting sides of the U; wherein the metatarsal protector when incorporated into safety footwear is interposed between the metatarsal regions, and when so interposed has an outer surface convex toward the inner surface of the upper and an inner surface concave toward the inner surface of the sole; wherein the metatarsal protector also comprises a force receiving part having respective upper and lower surfaces and overlying the said central part of the top portion outer surface with its lower surface spaced from the said central part, the force receiving part being of concave shape toward the said central part and having two spaced junctions with the metatarsal protector body; whereby crushing and impact forces applied to the force receiving part are operative to attempt to press the force receiving part toward the said central part of the top portion with conversion of such crushing and impact forces to corresponding longitudinal forces distributed along the junctions.

Further in accordance with the invention there is provided a toe and metatarsal protector that is a combination of the toe and metatarsal protectors of the invention. Brief Description of Drawings

Toe protectors, metatarsal protectors and combination toe and metatarsal protectors that are particular preferred embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein:

Figure 1 is a side elevation of a safety boot having a combination toe and metatarsal protector that is a first embodiment of the invention incorporated therein, shown in broken lines, each protector being an integrally molded body;

Figure 2 is an exploded perspective view of the combination protector of Figure 1, taken from above one side and to the rear;

Figure 3 is a cross-section on the line 3-3 of Figure 2, showing the protector assembled into a safety boot, and illustrating some possible modifications to the toe protector structure;

Figure 4 is an exploded perspective view of a second embodiment from the front and slightly to one side, in which force receiving parts for the toe and a forward part of the metatarsal protectors are separate from the protector bodies;

Figure 5 is a cross-section similar to Figure 3 taken on the line 5-5 in Figure 4;

Figure 6 is a transverse cross-section through the toe protector part of Figure 4 taken on the line 6-6 of Figure 4;

Figure 7 is a transverse cross-section through the metatarsal protector part of Figure 4 taken on the line 7-7 of Figure 4; and

Figures 8 and 9 are part cross-sections showing different ways in which a separate force receiving part of the embodiment of Figure 4 can engage with its protector body part. Modes for Carrying Out the Invention

Although for convenience the safety footwear shown in the drawings and described below is a safety boot, the invention is applicable equally to safety shoes, and both types of safety footwear are within the scope of the language of the claims. Footwear usually comprise an upper attached to a composite sole structure comprising as a minimum an insole and an outsole; other structural elements such as a midsole and, in the case of safety footwear a steel plate protecting against penetration by nails and similar sharp objects, may be interposed between the insole and outsole. For convenience in the language used in the claims any such composite sole structure is referred to simply as the footwear sole whatever its actual structure. For convenience the outer surface of an element is referenced using the same reference number as the element with the subscript A, while the corresponding inner surface reference employs the subscript B.

Figure 1 shows in side elevation a safety boot comprising a typical boot upper 10 having respective outer and inner surfaces 10A and 10B, and an outsole 12 having respective outer and inner surfaces 12 and 12B, the upper and the outsole having respective toe regions that register with one another and respective metatarsal regions that register with one another. A combination toe and metatarsal protector of molded plastics material is incorporated into the boot between the inner surface 10B of the boot upper and the inner surface 12B of the outsole. In this embodiment the combined protector comprises, in order from the toe, a toe part 14 between the two toe regions, a forward metatarsal part 16 between the two corresponding forward metatarsal regions, and a rearward metatarsal part 18 between the corresponding rearward metatarsal regions, the two metatarsal parts being of approximately the same length. In this embodiment each of the three parts is molded separately and attached to one another for storage and installation by a thin strip connector 19 of highly flexible material, such as a strip of synthetic fabric, glued or cemented to the inner surfaces of the protector parts. An insole 20 lies against the inner surface 12B of the outsole and extends into the interior of the toe part. An inner lining 21 of a soft material is fitted against the inner surfaces of the protector parts and the upper. The boot may comprise other functional parts, such as a midsole between the insole and outsole, and a metal or plastics material plate covering the instep to protect against penetration by spikes, but such other parts are not pertinent to the present invention and are not illustrated, the manner in which they may be incorporated into footwear being well known to those skilled in this particular art.

The toe protector part 14 comprises a generally U-shaped body having a top portion constituting the base of the U and two approximately parallel side portions constituting the sides of the U, the part therefore having an outer surface 14A that is convex toward inner surface 10B of the boot upper and an inner surface 14B that is concave toward the inner surface 12B of the outsole. In this embodiment the free ends of the toe protector side portions immediately adjacent to the outsole inner surface 12B are connected together by an integrally molded bottom connecting portion 22 that butts against the outsole inner surface, the corresponding part of the insole 20 resting on the inner surface of the bottom portion 22. Thus, impact or crushing forces applied to the toe protector top portion are, as with the prior art steel box toe protectors, transmitted through the protector body to the boot outsole 12 and thus to the ground. A toe protector structure with such an integral bottom connecting portion 22 provides maximum resistance to spreading apart of the side portion free ends under the downward acting forces to which it is subjected. However, the presence of such a connecting portion makes it impossible to employ some methods of boot and shoe fabrication, such as goodyear welts, and in such cases it must be omitted; its omission does give the advantages that the resultant protector is lighter, less expensive, and of lower height in side profile. In such a structure the side portion free ends terminate in a narrow inturned rim 23, the inner boundary of which is indicated in Figure 2 by a broken line, this rim providing a surface of increased area butting against the outsole inner surface 12B. The downward acting forces are transmitted through the rim to the outsole, and in its absence there is danger that the relatively narrow edge would cut deeply into the sole, reducing the safety clearance available for the wearer's toes.

The two parts of the metatarsal protector each also comprise a generally U-shaped body having respective top portions forming a base of the respective U and two side portions forming respective sides of the U, each protector part also having a respective outer surface 16A or 18A convex toward the inner surface 10B of the boot upper and a respective inner surface 16B or 18B concave toward the inner surface 12B of the boot outsole. The free ends of the side portions extend downwards at least sufficiently to engage the inner surface of the insole 20, and perhaps to engage the inner surface 12B of the outsole if the insole is sufficiently narrow at this location. It usually is not necessary, or even feasible, to connect the free ends together by a connector 22, as with the toe protector.

In this embodiment the central part of the top portion of the toe protector part 14 and the central part of the top portion of the forward metatarsal protector part 16 are each provided above its respective outer surface with a respective curved force receiving part 24 and 26 having respective outer surfaces 24A and 26A and inner surfaces 24B and 26B. No corresponding force receiving part is provided for the rearward metatarsal protector part 18, as will be explained below. The combined protector as incorporated into a safety boot thus comprises a toe protector force receiving part 24 overlying the outer surface 14A of the toe protector top portion and a metatarsal protector force receiving part 26 overlying the outer surface 16A of the top portion of the forward metatarsal protector part . Each force receiving part overlies, and is of concave shape toward, the central part of its respective protector part. Each force receiving part is integrally molded with its respective protector part and each has two transversely spaced longitudinally extending side junctions 28 and 30 respectively therewith, the lower surfaces 24B and 26B being spaced from the respective central parts so as to leave an arcuate air space 32 between them. In this embodiment the two toe protector side junctions 28 are joined at their ends nearer to the toe end by an end junction 34 to form a continuous junction that is generally U-shaped in plan from above. The free ends of the side portions of the two metatarsal parts are provided with respective inturned contact area increasing rims 35, as with the toe protector part.

The usual application point for the toe impact and crushing tests is indicated in Figure 1 by the arrow 36, while that for the metatarsal impact test is indicated by the arrow 38. The downward slope of the rearward metatarsal protector part 18 is sufficiently steep that heavy objects impacting thereon or crushing downward on the metatarsus are deflected downward onto the forward metatarsal protector part 16, and in particular onto the corresponding force receiving part 26. Moreover, it is possible to make the rearward part somewhat thicker while maintaining a satisfactory side profile, so that it is better able to withstand the applied forces without need to provide a force receiving part corresponding to that of the forward part . Any such downward acting crushing and impact forces are applied to the upwardly convex force receiving parts and are operative to attempt to press them toward the respective central part in the direction to increase their radius of curvature and to reduce the height of the arcuate air space 32, with the result that such downward crushing and impact forces are converted, at least initially, to corresponding outwardly acting longitudinal forces distributed principally along the two side junctions 28 and 30 and to a lesser extent along the end junction 34. These longitudinal forces are in turn converted, at least to some extent, to compression forces applied to the sides of the body which act as columns to withstand them, so that the impact and compression forces applied to the centre portion of the relatively unsupported arch are directed to the portions of the body more able to withstand them. Moreover, the structure permits advantage to be taken of the somewhat higher modulus generally available in compression for these materials. It has been found that the provision of such centrally disposed, vertically spaced force receiving plates makes it possible to reduce substantially the overall thickness of the upper portions of the protectors required to enable them to meet the test requirements, so that the height of their side profiles can be kept within limits such that they can successfully be incorporated into a safety shoe or boot without making the shoe or boot appear unacceptably bulky, and with the possibility that existing boot-manufacturing molds, as used with the prior-used steel toe boxes, can also be used with the plastics material protectors of the invention.

The resistance of each protector part to the applied impact and crushing forces is of course adjusted by adjustment of the thickness of different parts of the respective body. The resistance is also determined by the thickness of each force receiving part, and further by its effective radius of curvature, as compared to the radius of curvature of the body part top portion, a smaller radius resulting in a higher arcuate air space 32 and a corresponding increase in resistance, since the force receiving part must collapse further before it can contact the protector body and moves downward in contact with the body. Although in the embodiment described above only the forward part of the metatarsal protector is provided with a force receiving part and an accompanying air space 32, in other embodiments both parts can be so provided, the two parts being flexibly connected so that they can flex with the remainder of the protector. Although a combined toe and metatarsal protector has been illustrated, it will be apparent that the invention is equally applicable to separate toe and metatarsal protectors . The toe protector will usually not require longitudinal flexibility, and therefore will not be divided, while the metatarsal protector will usually require such flexibility, and can be made with more than two connected parts, especially in footwear and shoes of the larger sizes.

It usually is possible to tell immediately by visual inspection when a steel-toed safety boot or shoe has been so heavily impacted as to deform the toe box, since the metal does not recover once stressed beyond its yield point. Many high impact plastics materials employable in the invention have much higher resilience than metals, and a boot or shoe in which the protector has been so highly stressed as to be no longer fully effective may appear from a visual inspection to still be sound. Such a possibility can be avoided with the boots and shoes of the invention by providing a crush and impact detector means within one or all of the air spaces 32, the device being activated by a stress sufficient to reduce the air space height by more than a predetermined amount . A suitable simple, inexpensive device is, for example, a small, sealed pouch or capsule 39 of plastics material containing a distinctively colored ink or dye. If the capsule is squeezed too hard it will rupture under the internal pressure thus generated and discharge its contents on to the soft, and usually quite porous, lining 29, producing an instantly recognisable stain that will alert the user to the fact that the footwear has been subjected to such an excessive stress.

The integral molding of each protector part and its respective force receiving part has the advantage that it can be produced by a single operation, but does impose the limitation that the same material must be used throughout if a simple, one-stage molding process is to be employed. In commercial practice a number of molds are required to produce the range of sizes of footwear that must be available, and the molds required for manufacture of any integral embodiment will generally be more complex, and therefore more expensive, than those required when the components are separate, owing to the need to employ a retractable tongue, or similar device, to form the arcuate spaces 32, which would otherwise become filled with the molding material.

Figures 4 to 9 illustrate embodiments in which each protector body is formed separately from its respective force receiving part and this does have the advantage that different materials can be used for the two major components, making maximum use of the different mechanical properties usually available with different materials. They also provide the possibility of molding the toe protector body and one or both of the metatarsal protector bodies as a single component, which is then used in combination with a unitary force receiving part combining the two parts 24 and 26. In such an embodiment the integrally molded toe and forward metatarsal protector parts may be joined together by a relatively flexible narrow central connecting portion 40 that remains when two arcuate slots 42 are formed during the molding operation, or alternatively are formed by sawing through the molded part. The metatarsal protector part 16 is connected to the rearward part 18 in the same manner by a narrow central connecting portion 44 that remains from the formation of two arcuate slots 46 extending from the central portion, these slots also being formed either during the molding operation, or by sawing through the molded part. The relatively flexible connecting portions 40 and 44 permit longitudinal flexing of the protector to conform to the flexing of the boot under the action of walking.

In these embodiments the air spaces 32 in the protectors are formed by respective depressions 48 and 50 (see Figure 4) molded into the upper surfaces 14A and 16A of the respective protector part, each depression being shaped to provide two respective mutually facing, transversely spaced, longitudinally extending side surfaces 52 and 54 which respectively bound between themselves the central part of the respective top portion outer surface, these side surfaces extending outward from their central parts toward the inner surface 10B of the boot upper. The resultant combined protector is provided with a single upwardly convex curved force receiving plate member divided transversely into two connected parts 56 and 58 by arcuate slots 60 leaving a narrow central relatively flexible connection 62 between them, the plate member thus constituting the force receiving parts for both the toe and the forward metatarsal protector parts . Each plate member part has respective upper and lower surfaces and each has two transversely spaced longitudinally extending side edges 64 and 66, which in this embodiment are engaged respectively with the two side surfaces 52 and 54 of the respective protector body part.

In this embodiment the side surfaces 52 of the toe protector body part and the side edges 64 of the corresponding plate member part 56 are joined at their ends nearer to the toe end by an end surface and an end edge respectively to form respective continuous surfaces and edges that are generally U-shaped in plan from above. Also in this embodiment, to facilitate assembly of the protector into the boot the force receiving force receiving part is retained by outwardly extending pins 68 on the toe protector body part engaging in respective apertures 69 in the force receiving plate, preferably of the same plastics material as the protector body and molded therewith, these pins serving also to connect the force receiving part to the forward metatarsal protector part, so that separate connecting means are not required. Such connecting pins can also be provided for the metatarsal protector part or parts, although such a structure is not illustrated. Alternatively the protector body and force receiving part can be held together for storage and assembly by adhesive, either applied as spots or lines at strategic locations or as a continuous line around the peripheries of the depressions 48 and 50 and the plate member.

Any such crushing and impact forces applied to the force receiving part are operative to attempt to press the respective force receiving part toward the respective central part in the direction to flatten the force receiving part and to reduce the height of the arcuate air space 32, thereby forcibly butting its side edges 46 against the two cooperating side surfaces 52 and 54 with conversion of such crushing and impact forces to corresponding butting forces distributed principally along the side surfaces and to a lesser extent along the curved end surface. As with the embodiment of Figures 1-3, these butting forces are in turn converted at least to some extent to compression forces applied to the sides of the body which act as columns to withstand them, so that the impact and compression forces applied to the centre portion of the relatively unsupported arch are directed to the portions of the body more able to withstand them. Although in the embodiments illustrated the force receiving part edges 46 and 52 are butted against the corresponding side and end surfaces 36, 38 and 50, in other embodiments a small clearance may be provided between the edges and surfaces so that some flattening of the force receiving part takes place before the edges and surfaces engage. The force receiving part can be of molded plastics material or of sheet steel, since such a simple component can be produced relatively inexpensively by stamping. Figure 7 illustrates a structure which may be employed with both the toe and metatarsal protectors to increase their resistance to spreading apart of the side portions under the applied forces in the absence of a connecting portion 22. Such resistance is necessary to ensure that these forces are maintained as much as possible as compression forces. Figure 7 shows the metatarsal protector side rims 35 provided as close as possible to the side portions inner surfaces with apertures 74 into which are inserted downward extending double headed pins 76, which subsequently are molded securely into the sole during its formation by the molding operation. The rims 23 of the toe protector may be similarly provided with such apertures 74 and pins 76.

Another way of providing some additional resistance to such spreading forces is illustrated in Figure 2, comprising several complete wraps of a flexible tape 78 tightly encircling the toe protector body, as shown in broken lines. The tape is of the type that is particularly resistant to longitudinal stretching under tension, such as one with glass or carbon fibres extending longitudinally and attached to or embedded in a suitable matrix material . A number of such tapes are available commercially and a typical tape employing glass fibres is of width 12.5mm (0.5in) and thickness 0.125mm (0.005in) .

As will be seen from Figures 4 and 5, the surfaces 52 and 54 are inclined inward toward one another as they protrude from the central part of the upper surface of the top portion of the respective protector body part, so that the resultant corners are less than a right angle, and the edges of the force receiving parts are correspondingly chamfered to the same angle, so that as the downward acting forces increase the edges of the force receiving parts are wedged even more firmly into the corners. Instead, to facilitate the molding operation and to simplify the production of the force receiving plate, the surfaces may protrude perpendicularly from the central parts of the respective upper surface of the top portions of the protector body parts, as shown for example in Figure 8, and chamfering of the plate part edges is not required.

In the embodiments described the edges of the force receiving parts engage two transversely spaced longitudinally extending surfaces and a connecting end surface of the toe protector part body, and two transversely spaced longitudinally extending surfaces of the metatarsal protector part body. In other embodiments not specifically illustrated the force receiving part edges may, particularly with one which is solely a toe protector, instead engage two longitudinally spaced transversely extending surfaces of the body, or the force receiving part may have both its longitudinally extending edges and its transversely extending edges engageable with cooperating surfaces of the protector body, the force receiving part having a generally domed shape; in such embodiments it will be usually be necessary to provide separate force receiving parts for the toe protector and the part or parts of the metatarsal protector.

In the embodiments so far described the surfaces 52 and 54 are provided by forming corresponding depressions in the central portions of the protector bodies, but instead a structure such as is illustrated by Figure 9 can be used in which the side surfaces are provided by outward extending ridges 72 molded into the upper surfaces of the protector body parts.

There is a wide range of moldable materials that can be used in the production of the protectors, such as high density polyethylenes, high density polypropylenes, epoxies polyurethanes , polycarbonates, ABS resins, polyesters, high impact nylons, and composites and alloys of such resins, all of which may be reinforced with glass or carbon fiber. Specific materials are polycarbonates sold under the trademarks "MAKROLON 9415" (Bayer-Mobay) , " EXAN 500-BL2176" (G.E. Plastics) and "NERLON" ; polyurethanes sold under . "ISOP AST-202-lgf40" (Dow), "BAYFLEX 257/954/and 956" (all by Bayer) ; polycarbonate/polyurethane alloys sold under "TEXIN 4210 and 4215 (Bayer) ; polybutylene terephthalate polycarbonate sold under "XENOY 5720-BK1066" (G.E. Plastics) ; polyamide sold under "DURETHAN BC402" (Bayer) ; polyesters sold under "HYTREL" and "RYNITE"; high impact nylons sold by Bayer with designations "BC303", "BC402" and "9415Z", and those sold under the trade mark "ZYTEL" with designations "Nylon 66", "Supertough Nylon Sl-66" and "Nylon 612. As with any commercial product, and particularly one that is so price sensitive as explained above, there are a number of factors that must be balanced in making the choice, including the cost of the chosen material and of its fabrication, and the width and height that can be tolerated in the final product .

In a particular preferred embodiment as illustrated by Figure 3, for an 8D size boot, employing the material sold under "MAKROLON-9415" (glass fiber reinforced) , the thickness of the side walls of the protectors 12 and 16 was 3.5mm (0.140in), that of the part of the protector bodies below the spaces 32 was 3.4mm (0.135in), and that of the force receiving parts 24 and 26 was 2.5mm (O.lOOin) . The arcuate spaces 32 had a width of 5.0cm (2ins) and a maximum height of 3.0mm (0.120in) . In an embodiment as illustrated by Figures 4-7, employing a glass fiber filled polyester the overall thickness of the side and top portions of the body of the toe protector 14 was 3.125mm (0.125in), increasing to 4.7mm (0.1875in) in the neighbourhood of the side and end surfaces 52, so that this overall thickness is maintained at the location of the depression 48, while the thickness of the bottom portion was 1.56mm (0.0625in) . The vertical height of the side surfaces 52 was also 1.56mm (0.0625in), while the thickness of the force receiving part 56, which was of uniform thickness, was the same so that its edges that butt the surfaces 52 were also of the same dimension. The force receiving part was of a polycarbonate resin and its curvature relative to that of the toe protector body top portion was such that at its centre the arcuate air space 32 was 1.25mm (O.OSOin) in height. Increase of this air space dimension will increase the resistance of the protector to the applied forces but with an increase in the profile height of the protector; the specific value will therefore depend upon the size of the shoe or boot, the material from which the protector has been made, and the level of the certification that is required.

The dimensions of the body part and force receiving part for the metatarsal protector forward part 16 were the same as for the toe protector, while the thickness of the top portion of the metatarsal protector rearward part was somewhat thicker, namely 4.375mm (0.175in), the rear arcuate edge of the rearward part being tapered so that the protector will merge smoothly with the shoe and boot layers between which it is incorporated.

List of Reference Numbers

10. Shoe or boot upper

10A. Shoe or boot upper outer surface

10B. Shoe or boot upper inner surface

12. Shoe or boot outsole

12A. Shoe or boot outsole outer surface

12B. Shoe or boot outsole inner surface

14. Toe protector part

14A. Toe protector part outer surface

14B. Toe protector part inner surface

16. Metatarsal protector forward part

16A. Metatarsal protector forward part outer surface

16B. Metatarsal protector forward part inner surface

18. Metatarsal protector rearward part

18A. Metatarsal protector rearward part outer surface

18B. Metatarsal protector rearward part inner surface

19. Flexible strip connecting toe and metatarsal protectors

20. Shoe or boot insole

21. Inner lining for upper

22. Toe protector part connecting bottom portion

23. Toe protector bottom edge inturned rim

24. Toe protector force receiving part

26. Metatarsal protector force receiving part

28. Toe protector side junctions

30. Metatarsal protector side junctions

32. Arcuate spaces between force receiving parts and protector top portions

34. Toe protector end junction

35. Metatarsal protector bottom edges inturned rims

36. Impact point for toe protector impact test

38. Impact point for metatarsal protector impact test

39. Impact detector in spaces 32

40. Connection between toe and metatarsal protector parts 42. Slots forming connection 40

44. Connection between metatarsal protector parts

46. Slots forming connection 44 48. Depression in toe protector top portion

50. Depression in metatarsal protector top portion

52. Side surfaces in toe protector depression

54. Side surfaces in metatarsal protector depression

56. Force receiving part for toe protector

58. Force receiving part for metatarsal protector

60. Slots separating common force receiving plate into parts

62. Connection between force receiving parts 56 and 58

64. Side edges of toe protector force receiving part 56

66. Side edges of metatarsal force receiving part 58

68. Securing pins holding force receiving plate to toe protector body 70. Apertures receiving securing pins 68 72. Outward extending ridges forming surfaces 52 and 54 74. Apertures in rims 23 and 35 receiving retaining pins 76 76. Pins in apertures 74 to oppose spreading of side portions 78. Tape wrapped around toe protector to oppose spreading of side portions

Claims (44)

I Claim :

1. A toe protector (14) for safety footwear that comprise an upper (10) and a sole (12) joined to one another, the upper and sole each having respective outer and inner surfaces (10A, 10B, 12A and 12B) and having respective registering toe regions,- characterised in that the toe protector (14) comprises a generally U-shaped body molded from plastics material, having a top portion constituting a base of the U and two side portions constituting respective sides of the U; wherein the toe protector (14) when incorporated into safety footwear is interposed between the upper and sole toe regions, and when so interposed has an outer surface (14A) convex toward the inner surface (10B) of the upper and an inner surface (14B) concave toward the inner surface (12B) of the sole,- wherein the toe protector (14) also comprises a force receiving part (24) having respective upper and lower surfaces and overlying the central part of the top portion outer surface (14A) with its lower surface spaced from the said central part, the force receiving part (24) being of concave shape toward the said central part and having two spaced junctions (28) with the toe protector body; whereby crushing and impact forces applied to the force receiving part (24) are operative to attempt to press the force receiving part (24) toward the said central part of the top portion with conversion of such crushing and impact forces to corresponding longitudinal forces distributed along the junctions (28) .

2. A toe protector (14) as claimed in claim 1, characterised in that the protector body and the force receiving part (24) are molded integrally with one another to provide respective integral junctions (28) between the force receiving part (24) and the protector body.

3. A toe protector (14) as claimed in claim 1 or 2, characterised in that the junctions (28) of the protector body and the force receiving part (24) are joined at their ends nearer to the toe end respectively by an end junction (34) to form a continuous junction that is generally U-shaped in plan.

4. A toe protector (14) as claimed in any one of claims 1 to 3, characterised in that the two side portions of the toe protector body have free ends adjacent to the sole and the two free ends are connected by an integrally molded bottom portion (22) that butts against the sole (12) .

5. A toe protector (14) as claimed in any one of claims 1 to 4, and comprising a crush and impact indicating means (39) interposed between the force receiving part (24) and the remainder of the protector body.

6. A toe protector (14) as claimed in any one of claims 1 to 5, characterised in that the crush and impact indicating means (39) comprise a capsule of ink or dye that is ruptured by a crush or impact force to discharge its contents into the footwear.

7. A toe protector (14) as claimed in any one of claims l to 6, characterised in that the side portions are provided with respective apertures (74) receiving pins (76) that are molded into the footwear sole (12) to resist spreading apart of the side portions under the effect of the crushing and impact forces .

8. A toe protector (14) as claimed in claim 1, characterised in that the toe protector body is provided at its top portion outer surface with two mutually facing, spaced surfaces (52) extending outward from the outer surface toward the inner surface (12B) of the upper, the surfaces (52) bounding between them the central part ot the top portion outer surface; wherein the toe protector (14) also comprises a separate force receiving part (56) having respective upper and lower surfaces and overlying the central part with its lower surface spaced from the said central part, the force receiving part (56) being of concave shape toward the said central part and having two spaced edges (64) engageable at respective junctions (28) with the two surfaces (52) of the protector body; whereby crushing and impact forces applied to the force receiving part (56) are operative to attempt to press the force receiving part (56) toward the said central part and to forcibly butt its edges (64) against the two cooperating surfaces (52) with conversion of such crushing and impact forces to corresponding butting forces distributed along the surfaces (52) .

9. A toe protector (14) as claimed in claim 8, characterised in that the two spaced surfaces (52) of the protector body are transversely spaced longitudinally extending side surfaces and the two spaced edges (64) of the force receiving part (56) are corresponding transversely spaced longitudinally extending side edges .

10. A toe protector (14) as claimed in claim 8 or 9, characterised in that the surfaces (52) of the toe protector body are provided by a depression (48) molded into the upper surface of the protector body.

11. A toe protector (14) as claimed in any one of claims 8 to 11, characterised in that the surfaces (52) of the toe protector body are provided by outward extending ridges (72) molded into the upper surface of the protector body.

12. A toe protector (14) as claimed in any one of claims 8 to 11, characterised in that the force receiving part (56) comprises a thin molded sheet of plastics material.

13. A toe protector (14) as claimed in any one of claims 8 to 11, characterised in that the force receiving part (56) comprises a thin formed sheet of metal.

14. A toe protector (14) as claimed in any one of claims 8 to 11, characterised in that the force receiving part (56) is mounted on pins (68) protruding from the toe protector body.

15. A metatarsal protector (16, 18) for safety footwear that comprise an upper (10) and a sole (12) joined to one another, the upper and sole each having respective outer and inner surfaces (10A, 10B, 12A and 12B) and having respective registering metatarsal regions,- characterised in that the metatarsal protector (16, 18) comprises a generally U-shaped body molded from plastics material, having a top portion constituting a base of the U and two side portions constituting sides of the U; wherein the metatarsal protector (16, 18) when incorporated into safety footwear is interposed between the metatarsal regions, and when so interposed has an outer surface convex toward the inner surface (10B) of the upper and an inner surface (16A, 18A) concave toward the inner surface (12B) of the sole; wherein the metatarsal protector also comprises a force receiving part (26) having respective upper and lower surfaces and overlying the said central part of the top portion outer surface with its lower surface spaced from the said central part, the force receiving part being of concave shape toward the said central part and having two spaced junctions (30) with the metatarsal protector body,- whereby crushing and impact forces applied to the force receiving part (26) are operative to attempt to press the force receiving part (26) toward the said central part of the top portion with conversion of such crushing and impact forces to corresponding longitudinal forces distributed along the junctions (30) .

16. A metatarsal protector (16, 18) as claimed in claim 15, characterised in that the protector body and the force receiving part (26) are molded integrally with one another to provide respective integral junctions (30) between the force receiving part (26) and the protector body.

17. A metatarsal protector (16, 18) as claimed in claim 15 or 16, and comprising a crush and impact indicating means (39) interposed between the force receiving part and the remainder of the protector body.

18. A metatarsal protector (16, 18) as claimed in any one of claims 15 to 17, characterised in that the crush and impact indicating means (39) comprise a capsule of ink or dye that is ruptured by a crush or impact force to discharge its contents into the footwear.

19. A metatarsal protector (16, 18) as claimed in any one of claims 15 to 18, characterised in that the side portions are provided with respective apertures (74) receiving pins (76) that are molded into the footwear sole to resist spreading apart of the side portions under the effect of the crushing and impact forces .

20. A metatarsal protector (16, 18) as claimed in any one of claims 15 to 19, characterised in that the metatarsal protector body is provided at its top portion outer surface with two mutually facing, spaced surfaces (54) extending outward from the outer surface toward the inner surface (12B) of the upper, the surfaces (54) bounding between them the central part of the top portion outer surface,- wherein the metatarsal protector (16, 18) also comprises a separate force receiving part (58) having respective upper and lower surfaces and overlying the central part with its lower surface spaced from the said central part, the force receiving part (58) being of concave shape toward the said central part and having two spaced edges (66) engageable at respective junctions (30) with the two surfaces of the protector body,- whereby crushing and impact forces applied to the force receiving part (58) are operative to attempt to press the force receiving part (58) toward the said central part and to forcibly butt its edges (66) against the two cooperating surfaces (54) with conversion of such crushing and impact forces to corresponding butting forces distributed along the surfaces (54) .

21. A metatarsal protector (16, 18) as claimed in claim 20, characterised in that the two spaced side surfaces (54) of the protector body are transversely spaced longitudinally extending side surfaces (54) and the two spaced edges (66) of the force receiving force receiving part are corresponding transversely spaced longitudinally extending side edges (66) .

22. A metatarsal protector (16, 18) as claimed in claim 20 or 21, characterised in that the surfaces (54) of the metatarsal protector body are provided by a depression (50) molded into the upper surface of the protector body.

23. A metatarsal protector (16, 18) as claimed in claim 20 or 21, characterised in that the surfaces (54) of the metatarsal protector body are provided by outward extending ridges (72) molded into the upper surface of the protector body.

24. A metatarsal protector (16, 18) as claimed in any one of claims 20 to 23, characterised in that the separate force receiving part (58) comprises a thin molded sheet of plastics material .

25. A metatarsal protector (16, 18) as claimed in any one of claims 20 to 24, characterised in that the separate force receiving part (58) comprises a thin formed sheet of metal .

26. A metatarsal protector (16, 18) as claimed in any one of claims 20 to 25, characterised in that the force receiving plate member (58) is mounted on pins (68) protruding from the metatarsal protector body.

27. A metatarsal protector (16, 18) as claimed in any one of claims 20 to 26, characterised in that the protector body and the separate force receiving part (58) are each divided along its length by respective transversely extending slots (46, 60) to increase the longitudinal flexibility of the protector and facilitate corresponding flexing of footwear in which it is incorporated under the action of walking.

28. A combined toe and metatarsal protector (14, 16, 18) for safety footwear that comprise an upper (10) and a sole (12) joined to one another, the upper and sole each having respective outer and inner surfaces (10A, 10B, 12A and 12B) and having respective registering toe and metatarsal regions; wherein the combined protector comprises a toe protector part (14) and a metatarsal protector part (16, 18) molded from plastics material attached to one another, each of said parts comprising a generally U-shaped body having a top portion constituting a base of the U and two side portions constituting sides of the U; the toe and metatarsal protector (14, 16, 18) when incorporated into safety footwear being interposed between the toe and metatarsal regions, and when so interposed each having an outer surface convex toward the inner surface (10B) of the upper and an inner surface concave toward the inner surface (12B0 of the sole; and wherein the toe and metatarsal protector (14, 16, 18) also comprises for each of its parts a respective force receiving part (24,26) having respective upper and lower surfaces and overlying the respective central part of the respective top portion outer surface with its respective lower surface spaced from the respective central part, each force receiving part (24, 26) being of concave shape toward the respective central part and having two spaced junctions (28, 30) with the respective protector body part; whereby crushing and impact forces applied to each force receiving part (24, 26) are operative to attempt to press the force receiving part (24, 26) toward the respective central part with conversion of such crushing and impact forces to corresponding longitudinal forces distributed along the junctions (28, 30) .

29. A toe and metatarsal protector (14, 16, 18) as claimed in claim 28, characterised in that each protector body part and the corresponding force receiving part (24, 26) are molded integrally with one another to provide respective integral junctions (28, 30) between the force receiving parts (24, 26) and the protector body parts.

30. A toe and metatarsal protector (14, 16, 18) as claimed in claim 28 or 29, characterised in that the side junctions (28) of the toe protector body part are joined at their ends nearer to the toe end by an end junction (34) to form a continuous junction that is generally U-shaped in plan.

31. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 30, characterised in that the two side portions of the toe protector part (14) have free ends adjacent to the sole and the two free ends are connected by an integrally molded bottom portion (22) that butts against the sole .

32. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 31, characterised in that the toe protector body part (14) and the metatarsal protector body part (16, 18) are connected together for storage and/or installation by a longitudinally extending thin piece (19) of flexible material.

33. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 32, and comprising a crush and impact indicating means (39) interposed between the force receiving part (24, 26) and the remainder of the protector body.

34. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 33, characterised in that the crush and impact indicating means (39) comprise a capsule of ink or dye that is ruptured by a crush or impact force to discharge its contents into the footwear.

35. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 34, characterised in that the side portions are provided with respective apertures (74) receiving pins (76) that are molded into the footwear sole to resist spreading apart of the side portions under the effect of the crushing and impact forces .

36. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 28 to 35, characterised in that each protector body is provided at its top portion outer surface with two mutually facing, spaced surfaces (52, 54) extending outward from the outer surface toward the inner surface (12B) of the upper, the surfaces (52, 54) bounding between them the central part of the respective body; wherein each protector also comprises a separate force receiving part (56, 58) having respective upper and lower surfaces and overlying the respective central part with its lower surface spaced from the said central part, the force receiving part (56, 58) being of concave shape toward the said central part and having two spaced edges (64, 66) engageable at respective junctions (28, 30) with the two surfaces (52, 54) of the protector body; whereby crushing and impact forces applied to the force receiving part (56, 58) are operative to attempt to press the force receiving part (56, 58) toward the said central part and to forcibly butt its edges (64, 66) against the two cooperating surfaces (52, 54) with conversion of such crushing and impact forces to corresponding butting forces distributed along the surfaces (52, 54).

37. A toe and metatarsal protector (14, 16, 18) as claimed in claim 36, characterised in that the two spaced surfaces (52, 54) of each protector body are transversely spaced longitudinally extending side surfaces (52, 54) and the two spaced edges (64, 66)) of the respective force receiving part are corresponding transversely spaced longitudinally extending side edges (64, 66) .

38. A toe and metatarsal protector (14, 16, 18) as claimed in claim 36 or 37, characterised in that the side surfaces (52, 54) of the toe protector body part and the side edges (64, 66) of the respective force receiving part (56, 58) are joined at their ends nearer to the toe end respectively by an end surface and an end edge to form respective continuous surfaces and edges that are generally U-shaped in plan.

39. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 38, characterised in that the side surfaces (52, 54) are provided by depressions (48, 50) molded into the upper surface of the respective protector body part .

40. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 38, characterised in that the side surfaces (52, 54) are provided by outward extending ridges (72) molded into the upper surface of the respective protector body part.

41. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 40, characterised in that each force receiving part (56, 58) comprises a thin molded sheet of plastics material.

42. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 40, characterised in that each force receiving part (56, 58) comprises a thin formed sheet of metal .

43. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 42, characterised in that each force receiving part (56, 58) is secured by pins (68) to the respective protector body part .

44. A toe and metatarsal protector (14, 16, 18) as claimed in any one of claims 36 to 43, characterised in that the protector body part (14, 16 , 18) and the respective force receiving part (56, 58) are each divided along its length by respective transversely extending slots (42, 60) to increase the longitudinal flexibility of the protector and facilitate corresponding flexing of footwear in which it is incorporated under the action of walking.