NZ205077A - Cricket pad or other leg guard with flexible knee zone - Google Patents

Description

2 05077 Priority Dat-3{s): - CompSete Specification Filed: Class: 1.|I0.4? *.

)) Publication Date: ■hk. ' P.O. Journal, No: IT-H Uitc'er the provisions of Rfegif* lation 23 (!) the SpeciP,cation h.'.s be-n ante-dated to &t. i Initials N. Z.No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION "IMPROVEMENTS IN OR RELATING TO LEG GUARDS." We, STAFFORD RUBBER COMPANY LIMITED, a British company of Ringway Industrial Estate, Eastern Avenue, Lichfield, Staffordshire WS 1.37 SF, England I ' 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 : - ~ ^ (Followed by 1A.) 205077 IMPROVEMENTS IN OR RELATING TO LEG GUARDS This invention relates to leg guards, in particular to leg guards for protecting the ankles, shins, knees or other parts of the legs of games players. The invention is concerned particularly with cricket pads, and it is with reference to cricket pads that the following description particularly relates.

The conventional form of cricket pad provides adequate protection for the players but is of a structure whose production is labour-intensive and therefore expensive.

There is, in consequence, a demand for a pad that can be produced simply and cheaply and yet provide satisfactory protection for the player.

Various proposals have been made to manufacture cricket pads from plastics materials but none of these have gone very far in challenging the superiority of the conventional pad, despite the expense of the latter. One of the principal disadvantages of the pads of plastics materials hitherto proposed is that, where they have been of sufficient strength to withstand continual impact with the ball, they have not been sufficiently flexible to permit the user easily to bend his leg, and therefore they have not been comfortable to wear. -lfc- 2050 The present invention now provides a cricket pad or other leg guard which is of sufficient robustness and yet which is flexible enough to permit the user easily to bend his knee and therefore to wear the 5 guard with comfort.

Accordingly, the invention provides a cricket pad or other leg guard which comprises: a lower portion to protect, in use, at least the shin of the user; and an upper portion to protect', in use, at least 10 the lower part of the thigh of the user; and the lower and upper portions are disposed with reference to the overall dimensions of the leg guard so that, in use, the knee o'f the user is behind a flexible knee zone connecting, or comprising contiguous border 15 zones of, said lower and. upper portions, the leg guard having slots or other re-entrant means extending inwardly from the side edges of the guard to permit hinge-like movement of said lower and upper portions.

The leg guard preferably comprises a first, impact 20 resistant layer of a non-cellular plastics material and a second, resilient layer of a plastics material.

In the preferred embodiments of the invention said second layer serves the dual purpose of absorbing energy from the ball when it strikes the pad and also 25 of providing a comfortable surface to bear against the leg of the user.

-A- 205077 Increased flexibility of the pad in the region adjoining the upper and lower portions can be provided, for example, by means of a reduced thickness of pad (for example by having a reduced thickness of the 5 inner layer) in the knee zone of the pad. A further means of providing enhanced flexibility, which can be used, for example, with the feature referred to in the next preceding sentence , is the use of relief lines or other relief zones extending across the pad < in the knee zone (for example between the inner ends of opposed re-entrant means referred to above). These relief zones (which can, for example, be grooves or other areas of reduced thickness in the outer surface of the pad) can, if deep enough, facilitate bending 15 of the pad in the knee zone.

Said first and second layers can be, for example, layers of a laminate of plastics material. These laminates can be of two, three or more layers. In a preferred form of the invention the outer or outermost 20 layer consists of a wear-resistant flexible thermoplastic material. ~3 - 205077 This material is conveniently a polymer of an alpha-olefin, for example a polyethylene or a polypropylene. The material comprising the inner or innermost layer of the pad is conveniently a cellular or foam plastics material; and in one form of the invention this plastics material is a polymer of an alpha-olefin, for example a polyethylene or a polypropylene. In between these two layers, if desired, there can be a further layer or layers, for example a layer of a cellular or foam plastics material (for example of a polyethylene)polypropylene or other polyolefin) securely bonded to each of the other two layers or to the adjacent layers, as the case may be. In a preferred form of the invention this intermediate layer is of a polymer having the same chemical constitution as that of the inner layer.

In a preferred form of cricket pad according to' the present invention the thickness of the outer layer, any intermediate layer and inner layer are of progressively increasing amounts. For example,where the laminate or other multi-ply material consists of two layers, the ratio of thickness of the outer and inner layers is conveniently in the ran~e 1:12 to 1:8, for example 1:11 to 1:9; and where the laminate has three layers, the ratio of the thickness of the inner.laye • to the total thickness of the outer and intermediate layers is preferably in the range 3si to 3:2, for example 2:1 to 3:2, and the intermediate layer is preferably of greater thickness than the outer layer, a suitable ratio being in the range 10:1 to 2:1, for example 6:1 to 3:1.

J. ± O d 2 050 77 There is now described, "by way of example and with reference to the accompanying drawings, a cricket pad according to one embodiment of the present invention.

In the drawings: Figure 1 is a front elevation of the pad shown, for the sake of convenience, in a flat configuration prior to being shaped into a leg-embracing configuration; and Figure 2 is a perspective view of the pad in its leg-embracing configuration.

The pad comprises a laminate of first (outer) and second (inner) layers 10, 11 of thermoplastics material. The pad further comprises lower portion 10a, 11a and upper portion 10b, lib. The lower portion, in use, protects the shin and ankle of the user and the upper portion protects the lower part of his thigh. The outer layer 10, that is the layer facing outermost when the pad is in its leg-embracing configuration, comprises an elongate sheet of polyethylene having an overall shape which is generally rectangular and having two opposed side edges 12, 13, a top edge 14 and a bottom edge 15. The bottom edge has formed therein a centrally disposed recess 16 to receive the upper part of the foot of the user whereby the two adjacent salient 205077 portions 17, 18 can provide protection for his ankle bones. In the side edges 12, 13'thrre are two symmetrically disposed re-entrant slots 19,20 having enlargements 21, 22 at their inner ends. outer TheAayer 10 is of non-cellular polyethylene having a thickness of 1.5 mm, and the inner layer is of cellular or foam polyethylene having a thickness of 15 mm. The laminate providing layers 10 and 11 is one made by a process of flame bonding.

The polyethylene used for the outer layer conveniently has a specific gravity in the range 0.91 to 0.99» Examples of suitable polyethylenes are the low density polyethylene sold under the Trade Mark Lintacell (specific gravity 0.93) and the high density polyethylenes sold under the Trade Mark Frelen (specific gravity 0.96) and Hilex sold by British Celenese limited (specific gravity 0.96 ).

The cellular polyethylene used for the inner layer conveniently is one having a closed cell structure. It can have, for example, a density in the range 30 to 60 kg/m . Examples of suitable cellular polyethylenes are Frelen 30/06 ' (density 30 kg/m^), Frelen 50/06 (density 50 kg/m^), Lintacell 30/06 (density 30 kg/m'5) and Alveolit of the 2000 •2 range, for example 2015 (density 50 kg/m \ * 205077 A summary of the mechanical and physical properties of Alveolit 2000 is given below.

DIN Standard Unit Apparent density 53 420 kg/m^ 50 Tensile strength lengthwise ? 5,6 crosswise 53 571 kp/cm 4,0 (Specimen thickness 3mm) Elongation lengthwise 280 crosswise 53 571 fo 210 (Specimen thickness 3 mm) Tear resistance lengthwise ~ 2,8 crosswise 53 575 kp/cm 1,8 (Specimen thickness 3mm) Compressive strength p $ deflection 53 577 kp/cm 0,45 50$ deflection 1,2 Thermal conductivity at 0°C kcal/m.h.cfa 0,037 Working temperature range " °C -80 up to + 80 Water vapour transmission 53 122 g/m2.24h . 1,2 (Thickness 2mm) 205077 A summary of the mechanical and physical properties of Hilex is as follows.

Test Density - Tensile yield stress ISO R 527 Tensile modulus BS 4618 Izod' notched impact strength BS 2782 Melt index BS 3*12 Unit *2 g/cm kg/cm' kg/c m J/m g./lO mins. 0.96 310 11,200 480 0.6 Another suitable polyethylene for the outer layer is that sold under the trade mark RIGIDEX by B.P. Chemicals Limited. 205077 The shape and dimensions of the inner and outer layers is the same in the embodiment shown in the drawings.

The location of the re-entrant slots 19,20 in relation to the length of the guard is such that,when the pad is fitted to a leg of the user, his knee is in the region of the zone 23 between the two slots. It is, therefore, necessary that the pad should bend in that region, and this bending is facilitated by the re-entrant slots. Bending of the pad is further facilitated by arranging that the curvature of the upper portion of the pad is less than that of the lower portion, thereby permitting the side edges of the upper portion to pass outside the side edges of the lower portion when the user bends his knee. Moreover, the upper pad portion is disposed at an angle to the lower pad portion so that, after thermo forming, the border zones 24, 25 of the upper portion overlie the corresponding border zones 26, 27 of the lower portions. The purpose of this is to ensure that when the knee of the user is bended the upper portion passes over the lower portion without the edges fouling each other.

The contiguous border zones of the lower and upper pad portions have formed therein aligned, spaced apart slots 28, 29 and 30, 31 disposed on opposite sides of the re-entrant slots 19,20. These slots accommodate edge protectors 32, 33, 34, 35 disposed so that adjacent pairs contact each other and prevent wear of the border zones containing them. 205077 The drawings show a single pad suited for a user's right leg. A pair of pads can, for example, comprise two identical pads as shown, for instance,in Figures 1 and 2, or a pair can consist of two like, though not identical, pads having such differences as may "be necessary or desirable to suit right and le't legs.

The pad of the drawings has a series of slots 36, 36a in the respective side margins of the pad to receive straps for securing the pad on the user's leg; and two of the straps 37, 38 are shown, strap 37 being a buckle strap and strap 38 a tongue strap for engagement with buckle strap 37. Figures 1 and 2 are to be regarded as having a buckle strap attached to each of slots 36 and a tongue strap in each of slots 36a.

The straps shown in the drawings are of a novel construction in that, instead of being adapted for attachment to the pad by stitching or by riveting, they are provided with press-studs and associated stud-receiving recesses by means of which they can be fixed in place.

The pad h?.s formed in the surface of outer layer 10 shallow grooves 39 to simulate the stitching of a conventional c.anvas pad. 205077 The pad can be provided with slits or other ventilation means (not shown), preferably passing through both the inner and outer sheets, to enhance the comfort of the user, especially in hot climates.

The cricket pad described above with reference to the drawings can be made by the following method. From a sheet of a flame-bonded laminate of the non-cellular and cellular polyethylene there is cut a pad, the cutting operation providing at the same time the slots 28, 29, 30, 31 , strap-receiving slots 36, 36a and stitching simulating grooves 39. The resulting planar pad is subjected to a thermo-forming process to give it the desired degrees of curvature to provide the leg-embracing shape required of the pad, the radius of curvature of the upper portion of the pad being greater, preferably, than that of the lower portion for the reason given above. The edge protectors 32, 33, 34, 35 and straps 38, 39 can then be fitted in the respective slots to complete the pad.

The pad described above v/ith reference to the drawings has substantial advantages over a conventional canvas pad. a First, it is/weight of about half that of a conventional pad of senior grade. Secondly, it transmits through the pad a much smaller proportion of the force of a cricket ball striking its outer surface.

The following results (expressed in kilo-newtons) have been obtained using the procedure described in the Hprnnrl 2050 Draft British Standard dated June 1980 on leg guards which matured as BS 6183: Part 1: 1981.

Part of pad struck Pad of the Conventional by the ball Invention Canvas pad Instep Shin Knee 0.5 - 0.8 0.5 - 0.8 0.5 - 0.8 1.7 - 1.9 1.3 - 1.4 1.0 - 1.2 ^ 0 D 0 / 7

Claims (6)

WHAT WE CLAIM IS:

1. A cricket pad or other leg guard which comprises: a lower portion to protect, in use, at least the shin of the user; and an upper portion to protect, in use, at least the lower part of the thigh of the user; 5 and the lower and upper portions are disposed with reference to the overall dimensions of the leg guard so that, in use, the knee of the user is behind a flexible knee zone connecting, or comprising contiguous border zones of, said lower and upper portions, the 10 leg guard having slots or other re-entrant means extending inwardly from the side edges of the guard to permit hinge-like movement of said lower and upper portions.

2. A leg guard according to Claim 1, which comprises a first, impact-resistant layer of a non-cellular 15 plastics material and a second, resilient layer of a plastics material.

3. A leg guard according to claim 1 or 2, in which each have an enlargement at their inner end. 20 A.

A leg guard according to claim 1, 2 or 3 in which the curvature of the edge of the upper portion immediately above the re-entrant means is less than that of the edge of the lower portion immediately below said 25 entrant means to facilitate said hinge-like movement. 205077 -14-

5. A leg guard according to claim 4, in which protective means are provided to protect said edges from damage by abrasion between them as a result of said hingelike movement. 5

6. A leg guard according to any J of claims 2 to 5, in which said first layer is of a non-cellular polyethy]me or polypropylene.

7. A leg guard according to claim 6, in which the first layer is of polyethylene having a specific gravity 10 in the range from 0.91 to 0.99.

8. A leg guard according to any y of claims 2 to 7, in which the said second layer is of a cellular polyethylene or polypropylene.

9. A leg guard according to claim - 8, in which said 15 second layer is of polyethylene having a density in the range from 30 to 60 kg/m3 .

10. A leg guard according to any^of claims 2 to 9, in which the ratio of the thickness of said first and second layers is in the range from 1:12 to 1:8. 20 -)H— 205077 -15- .

11. A leg guard according to any 1 of claims 2 to 10, in which the first layer is of non-cellular polyethylene having a specific gravity in . the range from 0.91 to 0.99; the second layer is of closed-cell cellular 5 pdyethylene having a density in the range from 30 to. 60 kg/m3 ; and the ratio of the thickness of the first layer to that of the second layer is in the range from 1:9 to 1:11.

12. A leg guard according to claim 1, substantially 10 as described herein with reference to the accompanying drawings.

13. A cricket pad substantially as described herein . and substantially as shown in Figures 1 and 2 of the accompanying drawings.

1514. A flat precursor for a cricket pad as claimed in Claim 13, substantially as described herein and substantially as shown in Figure 1 of the accompanying drawings. STAFFORD RUBBER COMPANY LIMITED By Their Attorneys HENRY^HUGHES LIMITED