AU2011200865B2 - Metatarsal guards for footwear - Google Patents

Abstract

A moulded metatarsal guard for a gumboot which is integral with the gumboot, comprises a moulded polymeric material and includes a number of 5 impact absorption zones which are at least transversely compressible. duwm A0116759764v1 120137844 -10 -22 16

Description

AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Invention title: METATARSAL GUARDS FOR FOOTWEAR The following statement is a full description of this invention, including the best method of performing it known to us: duwm A0116759764v1 120137844 METATARSAL GUARDS FOR FOOTWEAR This is a divisional application divided out of Application No 2004231162, the entire 5 contents of which are incorporated by reference FIELD OF THE INVENTION This invention relates to metatarsal guards for footwear and in particular gumboots. 10 BACKGROUND OF THE INVENTION Legislation has placed the onus on management in industry to ensure the safety of workers and protect them from injury. Protective footwear is well-known and traditionally involved the inclusion of steel toe caps, mainly in lace-up shoes and boots. However it became apparent that the 15 metatarsal zone of the foot also requires protection and accordingly attempts were made to provide guards which are capable of being fitted to lace-up boots, usually being secured by means of the laces. These guards are however of no use for gumboots. Several strap-on metatarsal guards have been developed for gumboots, but these have a number of disadvantages. Not least of these is durability in that leg straps do not last 20 and under-foot straps are easily severed. An example of such a metatarsal guard is found in US Patent No. 3,995,382 - Smith, which is an external toe-cap and metatarsal guard assembly that is adapted for installation externally of a boot. Besides possible durability problems that might arise with this boot, it will be appreciated that stones and the like can easily become trapped between the guard and the boot leading to 25 discomfort. Accordingly there is a need for a gumboot with an integral metatarsal guard. In this regard, USA Patent No. 4,366,629 - Scherz and its European equivalent, European - 1 patent application no. 0 030 839 - Scherz describes a boot incorporating such an integral metatarsal guard. In this instance, the guard is made of steel. The steel guard is welded to a steel sole plate and the guard and sole plate assembly is then moulded integrally into the boot during moulding of the boot. It will be appreciated that this 5 process of manufacture is complex and expensive. In addition, the use of a steel metatarsal guard and sole plate assembly results in a very rigid boot. The development of modem polymeric materials enables manufacturers to move away from metal guards and instead use hardened polymeric materials, for example polycarbonate. These still need to bend however and one of the major difficulties 10 facing manufacturers is the trade-off between strength and flexibility. An example of such a boot is US Patent No. 4,102,062 - Adams, which describes a safety boot in which a metatarsal guard of hard, non-brittle synthetic plastics material is moulded integrally into the material of the boot with cushion layers above and below the metatarsal guard. Notwithstanding the use of plastics for the guard, the integral 15 moulding of the guard into the material of the boot will nevertheless yield a relatively rigid boot that would be unsuitable for use in most work situations involving kneeling and crouching and which therefore call for a more flexible forefoot in a boot. Even with the inherent flexibility of such materials, bonding a rigid guard to a gumboot remains an extremely difficult task. A typical example of this problem is illustrated in 20 French Patent No. 77 30049 - Phoenix Gummiwerke AG, which describes a gumboot that seeks to overcome these difficulties by attaching the metatarsal guard in-mould, during the manufacture of the boot, in effect moulding the protector rigidly to the exterior of the instep area of the boot. The metatarsal guard is said to be of a resiliently deformable material, but the integration thereof with the gumboot and the complete 25 attachment to the boot necessitated by the in-mould attachment process will render the boot relatively inflexible and unsuitable for use in occupations requiring a substantial amount of kneeling or crouching. One method of increasing flexibility without loss of strength is by the use of softer polyvinylchloride moulded into a web pattern which is designed to permit flexibility as 30 well as absorb shock. Unfortunately, much of the flexibility is lost once such guards are bonded onto a gumboot. -2- The flexibility of these webs is improved if the external covering layer is removed, as illustrated in UK Patent No. 2 098 456 -Foldvar Gumiipari Szovetkezet, but this leaves the web open for dirt and stones to clog the web. US Patent No. 6,389,715 - Krajcir seeks to overcome this apparent difficulty by 5 providing a metatarsal guard that is intended for integral installation in a boot. This patent publication describes the use of a plurality of rigid plastics arches that are intended to extend over the toecap and instep portions of the boot. The arches are interconnected by means of a flexible connector and notwithstanding the use of separate arches, the mere integration of the metatarsal guard arches into the material of the boot 10 will result in a relatively rigid and inflexible boot. US Patent No. 2001/0022039 describes a boot that seeks to overcome the problem of inflexibility by the provision of an integral metatarsal guard made of relatively flexible plastics material, the guard being intended for integration into the material of the boot over the instep portion of the boot. This metatarsal guard is nothing more than a thin, 15 impact absorbing insert. Similarly, an armadillo type overlapping arrangement works well but allows entrapment of stones. Whilst not immediately relevant to safety boots, German patent application no. 32 34 086 Al - Berta Frey & S6hne Schuhfabrik describes such a boot. This is a motorcycle boot in which the shin and instep portions of the boot are covered with an 20 extra layer of material arranged in raised folds. In this boot, no impact absorption is intended or provided. It is an object of this invention to provide a gumboot with a metatarsal guard which at least ameliorates these problems, can be permanently affixed to the gumboot, and is impact resistant and flexible. 25 SUMMARY OF THE INVENTION According to the invention, there is provided a metatarsal guard for a gumboot, the guard being of moulded polymeric material and including a plurality of impact absorption zones that are compressible at least transversely relative to the longitudinal 30 axis of the gumboot, the impact absorption zones being spaced apart and separated by at -3 least one zone of diminished impact absorption to permit flexion of the guard during walking, the guard including a plurality of spaced apart recesses and at least one raised zone when viewed from the underside thereof, the recesses constituting the impact absorption zones and the or each raised zone constituting a zone of diminished impact 5 absorption that spaces the recesses constituting the impact absorption zones apart from one another, each recess including one or more formations for absorbing impact. The zones of diminished impact absorption are preferably dimensioned such that, during flexion, the zones of impact absorption are aligned in close proximity to one another. In the preferred form of the invention, the guard comprises a generally arcuate 10 structure both longitudinally and transversely, the guard being dimensioned to extend from a point midway up the shin portion of a gumboot to a point at or near the point at which a reinforced toe cap of the gumboot ends, and which, when attached to a gumboot, spans the convex metatarsal and instep portions of the gumboot. The guard comprises a moulded, resiliently deformable polymeric material, preferably 15 polyvinylchloride and includes a series of recesses and raised zones when viewed from the underside thereof, the recesses including one or more formations for absorbing impact. These formations may comprise integral ridges which are preferably zigzag transversely across the width of the recesses. Other formations may also be effective, but the zigzag formations have been found to permit flexibility without loss of 20 protection. The raised zones comprise the zones of diminished impact absorption and when viewed from the upper side of the guard, comprise channels separating the impact absorption zones which appear in this view, as ridges. The series of zones is bordered by a bonding zone which forms the zone of attachment 25 during manufacture of the gumboot. The guard is bonded directly to the gumboot using a heat setting adhesive to render it integral with the gumboot and incapable of removal. In the one form of the invention, the impact absorbing formations (in the recesses constituting the impact absorption zones) comprise a plurality of complementally 30 shaped formations arranged in predetermined, spaced apart locations permitting compression of the zones in use. -4- In this form of the invention, the impact absorbing formations may comprise at least one integral ridge which zigzags transversely across the width of the each recess. In a preferred embodiment of this form of the invention, the complementally shaped formations comprise spaced apart rows of zigzag fins. 5 Also in the preferred form, the guard comprises a bonding zone, one or more impact absorption zones and an integral cover element. The bonding zone preferably comprises a peripheral strip bordering the absorption zone. The cover element may comprise a layer of polyvinylchloride over the absorption zones, the layer including one or more ridges and/or grooves which alternately provide 10 reinforcing and flexibility. According to a second aspect of the invention, a gumboot is provided that includes a metatarsal guard either bonded thereto or integrally formed therewith, the guard including one or more impact absorption zones, the zones being compressible at least transversely relative to the longitudinal axis of the gumboot, as described above and in 15 this specification. The metatarsal guard may include any one or more of the features of the metatarsal guard defined in the first aspect of the invention above. DETAILED DESCRIPTION OF THE INVENTION 20 Some example embodiments of the invention are described below with reference to the accompanying drawings in which: Figure 1 is a side view of a gumboot having metatarsal guard according to the invention with the guard shown partly in cross section; Figure 2 is a perspective view of the boot and the guard of Figure 1; 25 Figure 3 is an upper perspective view of the guard and boot of Figure 2 and also showing a guard detached from the boot that has been turned upside down; -5- Figure 4 is a side view of a gumboot and guard in accordance with another embodiment of the invention with the guard shown partly in cross section; Figure 5 is a side view of a gumboot and a guard in accordance with another embodiment of the invention with the guard shown partly in cross section; 5 Figure 6 is an upper perspective view of the guard and boot of Figure 5; and Figure 7 is an upper perspective view of the guard shown in Figure 5 with the guard turned upside down to show an underside thereof. In Figure 1, a gumboot 10 includes an integral metatarsal guard 12 of moulded 10 polyvinyl chloride bonded thereto. The guard in this preferred from of the invention comprises a series of alternating zones of impact absorption 14 and diminished impact absorption 16 which take the form of ridges and channels respectively when viewed from above. The impact absorption zones are recessed on the underside 18 thereof and include 15 transverse zigzag ridges 20 spanning the width of the recesses. The height of the absorption zone (or the depth of the recess) permits compression of the zone to disperse the force of any impact, while the zigzag ridges 20 are, like the entire guard, inherently compressible to further absorb and disperse the force of impact, thereby offering a two step impact absorption action. The inherent elasticity of the guard also further assists 20 in deflecting glancing impacts thereon. The ridges preferably have defined wall 22 and edges 24 as opposed to being arcuate to increase rigidity. The channels 16 are designed and dimensioned to permit flexion of the gumboot during walking, without reducing protection. This arrangement permits a degree of comfort 25 and wearability not possible with rigid metatarsal guards which are not formed integrally with the gumboot. In Figure 4, a gumboot 10 includes a metatarsal guard 12 of moulded polyvinylchloride bonded thereto. -6- The guard comprises a bonding zone 26 in the form of a peripheral strip of PVC bordering a series of four internal impact absorption zones 28. A cover element 30 (also integrally moulded PVC) prevents the ingress of dirt and particulates into the absorption zones. 5 In Figures 5 and 6, the guard includes a single absorption zone 32 comprising a series of complementally shaped, spaced apart, zig-zagging fins 34 (Figure 7) which can be compressed together to retain flexibility during bending of the guard. This arrangement is more clearly illustrated in Figure 7. Reinforcing ridges 36 are provided for increased strength. 10 The word 'comprising' and forms of the word 'comprising' as used in the description and in the claims does not limit the invention claimed to exclude any variants or additions. -7-

Claims (14)

1. A metatarsal guard for a gumboot, the guard being of moulded polymeric 5 material and including an integrally moulded cover element and a plurality of impact absorption zones that are compressible at least transversely relative to the longitudinal axis of the gumboot, the impact absorption zones being spaced apart and separated by at least one zone of diminished impact absorption to permit flexion of the guard during walking, the guard including a plurality of spaced apart recesses and at least one raised 10 zone when viewed from the underside thereof, the recesses constituting the impact absorption zones and the or each raised zone constituting a zone of diminished impact absorption that spaces the recesses constituting the impact absorption zones apart from one another, each recess including one or more formations for absorbing impact. 15

2. A metatarsal guard according to claim 1, in which the zones of diminished impact absorption are dimensioned such that, during flexion, the zones of impact absorption abut or are at least aligned in close proximity.

3 A metatarsal guard according to either of claim 1 or claim 2, which comprises a 20 generally arcuate structure both longitudinally and transversely, the guard being dimensioned to extend from a point midway up the shin portion of a gumboot to a point at or near the point at which a reinforced toe cap of the gumboot ends and to span the convex metatarsal and instep portions of the gumboot. 25

4. A metatarsal guard according to any one of the preceding claims, in which the polymeric material comprises polyvinylchloride. -8-

5. A metatarsal guard according to any one of the preceding claims, in which the impact absorbing formations within the recesses constituting the impact absorption zones comprise a plurality of complementally shaped impact absorbing formations arranged in predetermined, spaced apart locations, the formations being adapted to 5 permit compression of the impact absorption zones in use.

6. A metatarsal guard according to claim 5, in which the impact absorbing formations within the recesses constituting the impact absorption zones comprise integrally moulded ridges which zigzag transversely across the width of the recesses. 10

7. A metatarsal guard according to claim 6, in which the complementally shaped formations include spaced apart rows of zigzag fins.

8. A metatarsal guard according to any one of the preceding claims, in which the 15 zones of impact absorption and reduced impact absorption are bordered by a bonding zone which is adapted to form a zone of attachment by means of which, during manufacture of the gumboot, the guard may be bonded directly to the gumboot using a heat setting adhesive to render it integral with the gumboot. 20

9. A metatarsal guard according to claim 8, in which the bonding zone comprises a peripheral strip bordering the absorption zone.

10. A metatarsal guard according to claim 8, in which the cover element comprises an integrally moulded layer of polyvinylchloride over the absorption zones, the layer 25 including one or more ridges and/or grooves which alternately provide reinforcing and flexibility. -9-

11. A gumboot including a metatarsal guard according to any of the preceding claims which is bonded to the gumboot.

12. A gumboot including a metatarsal guard according to any one of claims 1 to 10 5 which is integrally formed with the gumboot.

13. A metatarsal guard substantially as described in any one of the embodiments in the detailed description of the invention with reference to the accompanying drawings. 10

14. A gumboot substantially as described in any one of the embodiments in the detailed description of the invention with reference to the accompanying drawings. - 10-