NZ588486A - Improvements in animal tags - Google Patents

Abstract

Disclosed is a tag for attachment to an animal. The tag includes a penetrating component having a pair of spaced apart penetrating members joined by an elongate intermediate portion. The penetrating members extend from respective ends of the intermediate portion. Each penetrating member has a stem with a first end joined to the intermediate portion and a second end terminating in a penetrating head. The penetrating head has a distal point and a base which forms a shoulder around the stem. The tag includes a complementary component, separate from the penetrating component. The complimentary component has a pair of apertures arranged to receive respective penetrating members of the penetrating component so as to provide positive engagement of each respective shoulder of the penetrating heads. Each stem has a bore open at the first end to receive a respective pin of an applicator to assist in piercing the skin of the animal and positively engage the shoulders within the apertures of the complementary component. A section of material of the intermediate portion between each bore and a respective end of the intermediate portion is dimensioned so that there is no overhanging part so as to prevent the penetrating component being dislodged by the animal from the complementary component after positive engagement of the shoulders with the complementary component.

Description

08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 05/29 58 8 4 8 6 *10059723450* No.: Date: NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION IMPROVEMENTS IN ANIMAL TAGS We GOLD RYTHMN PTY LTD of 145 Christies Road, Warragul, Victoria 3820, Australia and KCS Australia Pty Ltd of 25 Industry Court, Lilydale, Victoria 3140, Australia, hereby declare the invention, for which they pray that a patent may be granted to it, and the method by which it is to be performed, to be particularly described in and by the following statement: 1 INTELLECTUAL PROPERTY OFFICE OP N Z -8 OCT 2010 RECEIVED 08/10/2010 14:56 61-3-S8901337.

I PATENT ATTORNEY SERV PAGE 06/29 improvements tn animal TAGS Field of the Invention This invention relates to improvements in tags for attachment to an animal and their manufacture.

Background of the Invention Tagging of animals is done to provide identification of animals as wel t as tracking or monitoring the movement of animals. Recent tag designs have incorporated a pair of penetrating members on a penetrating component joined by a substantially flat joining member. Each of the penetrating members are designed to fit into slots of a j o locking member after penetrating the skin of the animal, through the use of a pin applicator. Once in place., the penetrating component having the penetrating members is designed not to come apart from its corresponding locking member between which the skin of the animal is secured. Identification is usually provided in the form of visual indicia provided on a flag, for example, attached to the locking member or on 15 the joining member of the penetrating component. Electronic components such as transponders can also be used to readily identify and track the animals.

Examples of prior art twin penetrating member animal tags are given in Australian patent Nos. 2007200078,2002248997 and 2003265730.

A particular disadvantage occurs when animals, having such tags fitted, rub the 20 part of its anatomy where the tag is located against an object such as a fence post, fence wire or gate. The joining member, which commonly resides on, for example, the back side of an ear of the animal, gets snagged against the object. The object is lodged between the ear of the animal and the underneath side of the joining member thus providing a point of purchase against which the animal can attempt to dislodge or 25 remove the penetrating members from the corresponding locking member. 2 03/16/2016 i 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 07/29 Once the tag is dislodged or totally removed it becomes very difficult and somewhat impossible to track and/or identify the animal.

Existing manufacturing techniques for manufacturing the locking member of the tag has led to no cap or cover being provided on the end of the bore of the female 5 member which receives the penetrating component. Such an open ended arrangement can potentially lead to infection of the animal where the tag is connected. Other manufacturing processes have provided a cap at the end of the bore to effectively make the receiving section a blind bore but this has generally involved a two-part or two-step manufacturing process. Firstly the bore or bores that act as a receiving 10 component axe formed as part of the female member and in the second step a thin cap is provided over the end of the bore in order to seal the unit, which is usually glued or friction welded over the bore end. This has the disadvantage of providing an additional step in the process which adds to the cost and time involved in such a two-part process.

Another problem in manufacturing such tags, which is primarily done through injection moulding of plastic materia], is that air can be trapped in the mould that forms the tag. If the trapped air is unable to escape from within the mould, it is compressed by the pressure of the incoming plastic material and squeezed into corners or crevices of the cavity of the second receiving part of the mould. This can prevent 20 the complete filling of the cavity with plastic material and lead to other defects as well, such as the air becoming so compressed that it eventually ignites and bums the surrounding plastic material. Thus, there is a requirement to sufficiently remove any trapped air in the moulding process.

Another problem with such a moulding process is that it can in some instances be 25 difficult to remove the male part of the mould through a narrow throat, which is Received at IPONZ on 24 February 2012 formed to provide entry by a penetrating member or stem that forms part of the male part of the tag, without weakening or destroying or otherwise deforming the plastic material around the throat.

The present invention provides an improvement to such tags and to the 5 manufacture of the tags.

The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art in Australia.

Summary of the Invention 10 According to a first aspect of the invention, there is provided a tag for attachment to an animal including: a penetrating component having a pair of spaced apart penetrating members joined by an elongate intermediate portion at respective ends of the intermediate portion, each penetrating member having a stem extending outwardly from the 15 intermediate portion and having a first end of the stem joined to the intermediate portion and a second end of the stem terminating in a penetrating head, the penetrating head having a distal point and a base forming a shoulder around the stem of the penetrating member; a complementary component, separate from the penetrating component, 20 having a pair of apertures arranged to recei ve respective penetrating members of the penetrating component so as to provide positive engagement of each respective shoulder of the penetrating heads with the complementary component; each stem having a bore open at the first end to receive a respective pin of an applicator to assist in piercing the skin of the animal and positively engage the 25 shoulders with the complementary component; 4 Received at IPONZ on 24 February 2012 wherein a section of material of the intermediate portion between each bore and a respective end of the intermediate portion is dimensioned so that there is no overhanging part of the intermediate portion at each end of the intermediate portion to prevent the penetrating component being dislodged by the animal from the 5 complementary component after positive engagement of the shoulders with the complementary component.

In an embodiment, the elongate intermediate portion has first and second ends and the position of the stem bores is such that a thin section of material forming part of the intermediate portion exists between each bore and a respective end of the 10 intermediate portion. A pair of opposed sides of the intermediate portion may be substantially parallel to one another and extend directly between the thin sections of material around each bore. Alternatively, the intermediate portion may have a pair of opposed sides that each taper outwardly from the first and second ends to meet at a mid-point in each side.

In a further embodiment the stem of each penetrating member has a first section of larger diameter than a second section of the stem, such that the second section is adjacent the penetrating head and protrudes through a respective aperture of the complementary component whereas the first section does not protrude through the respective aperture. The first section and second section of each penetrating 20 member may join at a transition area and the transition area can abut against a top surface of the complementary component around said pair of apertures.

The penetrating heads of the penetrating members may each have a pair of opposed flanges having a relatively sharp edge terminating at the distal point of the head, to assist In piercing the skin of the animal.

The shoulder of each penetrating head may be positioned in a locking engagement with the complementary component against a surface around a Received at IPONZ on 1 December 2011 respective aperture of the complementary component to ensure that the penetrating head is unable to detach from the complementary component.

The penetrating component is preferably integrally formed as a single unit. The complementary component is preferably integrally formed as a single unit.

The penetrating component and the complementary component may each be made by an injection moulding process.

In an embodiment of the invention, there is provided a method of manufacturing a component of a tag, the component adapted to receive and retain a penetrating member in a chamber after skin of an animal has been pierced by the penetrating member, the method including the steps of: forming material in the shape of the component using a male mould component and a female mould component; providing a channel in the male mould component to enable the release to atmosphere of air between the male and female mould components as the material is formed.

The method may include providing a reaction area around an opening to the chamber of the component against which a tool abuts in order to assist in withdrawing the male mould component after the formation of the material, the reaction area enabling resilient deformation of the component to enable the withdrawal of the male mould component.

The method may further include providing a shoulder between the chamber and a throat in the component so shaped to enable withdrawal of the male mould component but retain the penetrating member in the chamber, The method may further include producing the component integrally in a single step.

In an embodiment of the invention, there is provided a component of the tag manufactured by the abovementioned method.

Brief Description of the Drawings 08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 11/29 A preferred embodiment of the invention will hereinafter be described, by way of example only, with reference to the drawings in which: Figure la is a perspective view from above of a penetrating component of a tag for attachment to an animal according to an embodiment of the invention; Figure lb is a plan view of the penetrating component of Figure la; Figure lc is a front view of the penetrating component of Figure l a; Figure Id is a side view of the penetrating component of Figure 1 a; Figure 2 is a perspective view from above showing a further embodiment of a penetrating component of a tag ready to be fitted to a complementary component; i o Figure 3 is a perspective view from above showing the penetrating component fitted to the complementary component after the two penetrating members of the penetrating component have pierced a corresponding body portion of the animal; Figure 4 is a perspective view from above showing the penetrating component fitted and locked to the complementary component which has a flag for identification 15 of the animal; Figure 5 is a sectional side view of a mould in the process of producing a complementary female receiving member of a tag for attachment to an animal; Figure 6 is a sectional side view of the complementary female receiving member produced from the mould shown in Figure 5; Figures 7 (a), (b), (c), (d) and (e) are respectively a bottom view, front view, front sectional view, side view and side sectional view of a complementary female receiving member for receiving a pair of penetrating members of a penetrating component; and Figures 8 (a), (b), (c), (d) and (e) are respectively a perspective view, side sectional view, partial side sectional view, partial side sectional view and side view of 7 08/10/2010 _14:56 61-3-98901337 PATENT ATTORNEY SERV p, a tag having a single penetrating member engaged with a complementary female member; and Figures 8(f) and 8(g) are respectively exploded sectional views of Figures 8(b) and 8(c) showing a more detailed engagement of the penetrating member head in a 5 retaining cavity of the complementary female member.

Hftnilerl Description of the Preferred Embodiment With reference to Figures la to Id, there is shown a penetrating component (2) of an animal tag (1) having a pair of spaced apart penetrating members (4) each of which is separately joined or formed integrally with an elongate intermediate portion (6). 1 o Each of the penetrating members (4) has a stem (5) joined at a first end with the intermediate portion (6) and terminating at a distal or second end in a penetrating head (8), which is in the shape of an inverted cone. Other shapes for the penetrating head (8) arc possible, such that the head has a sharp point or apex (10) which is used to assist in protruding through the animal's skin, typically the ear. To assist in 15 penetrating the skin of the animal, a pair of flanges (12) are formed on the periphery of the penetrating head (8) having a relatively sharp edge and terminating at the point 00).

A pair of bores (14), which are preferably blind bores, are formed in the intermediate portion (6) and extend through a portion of the stem (5) of the penetrating 20 members (4) so that the penetrating members (4) are partially hollow. This provides an entry point for a corresponding set of pins of an applicator when inserting the penetrating component (2) into the animal's skin to be locked in the corresponding complementary component (3) shown in Figure 2.

The position of each of the bores (14) within the intermediate portion (6) is such 25 that there is substantially no overhang of material of the intermediate portion (6) 8 08/10/2010 14:56 Sl-3-98901337 PATENT ATTORNEY SERV PAGE 13/29 between the scction where each of the penetrating members are connected or joined to the intermediate portion (6) and the outer ends (18) of the intermediate portion (6). With reference to Figure lb, it can be seen that only a thin portion of material exists between an end (18) of the intermediate portion (6) and a respective bore (14) 5 presenting substantially no overhang that the animal can use as leverage in order to remove or dislodge the tag from the portion of the body to which it is attached. Similarly there is no excess material of the intermediate portion (6) at sides (20) of the intermediate portion (6) as the sides (20) are a continuation substantially in a straight line from where the curved sections of ends (18) cease at points (22). Thus, 10 substantially no overhang of the material of the intermediate portion (6) is present at sides (20). A slight variation is shown in Figure 2 where the intermediate portion (6) has side edges (20) that bow outward slightly to a point (24). Point (24) is the midpoint on each side (20) and each side (20) tapers outwardly from a respective end (18) to meet at the respective mid-point (24) so that the distance between each mid-15 point (24) of each side (20) is greater than the distance of a parallel line taken adjacent each end (18) across the centre of bore (14) and terminating at points (22). This presents substantially no overhang for which an animal can leverage against another object in order to prise free the tag from the animal.

Each stem (5) of the penetrating members (4) has essentially two sections of 20 varying diameter. A first scction (26) has a larger diameter compared to a second section (28) which is joined or formed with the first section (26) at a transition area (27). The first section (26) abuts against a top surface (30) of the complementary component (3) at a transition area (27) at the bores (32), which have a substantially circular cross-section. This is more clearly shown in Figure 4. The second section 25 (28) is sized so as to protrude through the bore (32) so that a shoulder (34) of each 9 .08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 14/29 penetrating head (8) is forced through a respective bore (32) by the application of an applicator. The shoulders (34) are positioned in locking engagement against an underneath surface of the complementary component (3) around the respective bore (32) so that it cannot be pulled back through the bore (32) and detached from the complementary component (3).

The bores (32) are substantially cylindrical in shape as opposed to a slot shape in prior art disclosures. Tt has been found that the slot-shaped locking means, which existed to allow for the growth of an animal, eventually over time made it easier for the penetrating member to be dislodged from the complementary component (3).

The penetrating component (2) is generally made of a hard plastic material such as nylon (nylon 6 or nylon 66) or polyurcthane (particularly TPU). The penetrating component (2) together with the penetrating members (4) have a shore hardness in the range of 70D to 90D, preferably 75D to 80D, or alternatively a Rockwell Hardness in the range (R) R94 to (R) R120. The complementary component (3) has 15a shore hardness in die range 90A to 100A, preferably around 95 A. Each of the penetrating component (2) and complementary component (3) are preferably separately injection moulded to form unitary or integral components. A flag (33) or similar projection can be integrally moulded to the complementary component (3), The greater density of the material of the penetrating component (2) provides added 20 strength to provide durability and robustness and also ensures that there is little flex available in the penetrating members (4) so that the tag (1) stays in place on the animal.

The penetrating component (2) is generally fitted from the back of the ear, but as mentioned previously any other part of the skin of the animal can be used where it 25 can be adequately folded and enable an identification flag, or similar surface area, to 08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV enable easy identification. Thus the component (2) is applied through the back of the ear, preferably between veins in the ear, and fitted to the complementary component (3) where for example a flag (33) is fitted and resides on the inside of the ear. A gap (36) is then produced which is where a portion of the animal's ear (or other part) is 5 located. A raised section (38) formed on a top surface of joining portion (40) between the bores (32) is used to provide a small gap for air to flow against the skin or inside part of the ear in order to assist in the healing of skin around the holes made by the penetrating heads (8).

The tag (2) is applicable to animals such as cattle, sheep, goats, pigs and other 10 livestock. The penetrating component (2) is sized differently depending on what animal the tag is applied to. in general for cattle the centre to centre dimension between the bores (14) is approximately 33mm and for sheep approximately 28mm. The length of the penetrating members (4) from the point (10) up to the top surface of the intermediate portion (6) is approximately 26mm for each of the tags used for 15 cattle and sheep. After the penetrating component (2) and complementary component (3) are applied and locked to one another, the gap between the components (2) and (3) is between 8mm and 11mm to allow for suitable ventilation and promotion of healing.

Shown in Figure 3 is the tag as it would be inserted on an animal with the 20 penetrating component (2) interlocked with the complementary component (3) whereby the shoulder (34) of each penetrating head (8) abuts against an underneath surface surrounding the bore (32) on an underside of the complementary component (3).

In Figure 4 there is shown a flag (33) that forms part of the complementary 25 component (3) and is integrally moulded therewith. n 08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 16/29 Referring to Figure 5 there is shown a male mould component (SO) and a female mould component (52) that are moved adjacent one another, through an injection moulding process, in order to form material (54) which defines a female complementary or receiving portion for a penetrating member of a penetrating 5 component. The material (54) is preferably a plastics material which in a molten form is forced into the female mould (52) and compressed by the force provided by the male mould component (50) to form the shape shown in Figure 5. So that no air is trapped within the space that eventually forms the receiving part from material (54). a groove or channel (56) which is formed in the male mould component (50) l o enables any trapped air to escape along the channel (56) and out to the atmosphere. In this way, the complete volume is filled with plastics material. The process is formed as a one step process in that the receiving portion has a cover or end cap (58) which covers the locking mechanism provided by the interconnection of the penetrating member and the complementary receiving member. The mould is so 15 shaped that the plastics material is formed in one unitary or integral part and provides tampcr-proofing for when the tag is attached to an animal. Furthermore there is no danger of infection as the locking mechanism is not exposed to the atmosphere.

Thus, if an animal owner, such as a farmer, wishes to cut a tag from the animal, with the tag having a flag identifying the animal, but cannot remove the male penetrating 20 member, due to the cap being in place, then the tag cannot be reused. There is therefore added security in the fact that the tag or the ID number on the tag cannot be transferred..

Also shown in Figure 5 is a foot or base region (60) of a tool, such as an ejector plate, which rests on an annular area, called a reaction zone or area (62), of the 25 cooled plastic material to assist in removing the male mould component (50). The 08/10/2010_ 14:5G 61-3-98901337 PATENT ATTORNEY SERV PAGE 17/29 reaction zone or reaction area (62) where the foot (60) of the ejector plate rests is located around the mouth (68) of the female complementary component (54) and can be formed as an annulus having a diameter of, for example, 5mro. The reaction zone (62), against which the ejector plate applies a force, enables resilient deformation of 5 the material surrounding the throat (66) of the female receiving part and around the mouth (68) as the male mould part is "bumped off'. Bumping off is difficult to achieve where there is a narrow throat (66). Bumping off is a process whereby a sliding core, in this case the male mould component (50), is retracted or pulled away from the receiving part but is pulled through a narrow section, being narrow throat 10 (66). The material around the throat (66) and mouth (68) can be deformed to enable the retraction of the head of the male mould part tlirough the narrow section whilst the plastics material is still hot so that, after withdrawal of the male mould component (50), the throat (66) and the retaining chamber (64) are resilient to resume their usual dimensions before the withdrawal of the male mould component 15 (50). The size of the reaction zone or area (62) depends upon the softness of the plastics material of the female complementary portion (54), however an increase in the so ftness of the material (54) requires an increase in the area of the reaction zone (62).

The throat (66) in this example is of a narrower diameter than the prior art so 20 that a smaller diameter pin or penetrating member can be used for the animal which provides less stress to the animal. As the throat (66) is narrower, it makes it harder for the penetrating member to pull out from the chamber (64). The depth of the throat (66) should be sufficient to provide enough strength to resist the retained penetrating member pulling out of the female portion (54). 13 08/10/2010 14:5G 61-3-98901337 PATENT ATTORNEY SERV PAGE 18/29 Various views of a complementary receiving female component (80) of a tag is shown in Figures 7a to 7e. Figure 7a. shows an underneath view of the female complementary component (80) having flag (82) attached, the component (80) formed as a pair of receiving members. Figures 7b and 7c show front views with 5 Figure 7c being a sectional view. Figures 7d and 7e are side views with Figure 7e also being a sectional side view of the female receiving component (80), The injection moulding process can apply to a single female receiving part or alternatively a dual female receiving part as shown in Figure 1.

Figures 8a to 8g show various views and sectional views of a tag having a male 10 penetrating member (90) and a female complimentary receiving component (92). With reference also to Figure 6, the shoulder (70) formed in the female component (58) have a radius that is of a size that will enable the male mould component (50) to be removed but will not allow the penetrating head of the penetrating component to be removed from the receiving part, A force of greater than 25 Newtons is required 15 before failure occurs at the shoulder (70). Typically, the radius of shoulder (70) is between ).3mm and 1,0mm.

As seen in Figures 8f and 8g ideally the shoulder (70) is round and have a radius but the profile or shoulder of the penetrating portion is square or sharp so that it is difficult to dislodge or remove through the throat (66). The male mould component 20 (50) will therefore have round shoulders corresponding to shoulder (70) so that easier withdrawal is possible of the male mould component (50) from the female mould component (52) during the manufacture of the tag component, The female complimentary component may generally be made from plastics material such as TPU which is an injectable polyurethane having a shore hardness of 25 around between 90A and 100A, preferably 95A. The penetrating members (4) of i4 08/10/2010 14:56 61-3-98901337 PATENT ATTORNEY SERV PAGE 19/29 penetrating component (2) may be made from plastics material such as TPU having a shore hardness in the range 70D to 90D, preferably in the range 75D to 80D. Alternatively the penetrating members (4) may be made from plastics material such as TPU having a Rockwell Hardness in the range(R) R94 to (R) R120. Nylon 6 or Nylon 5 66 may also be used as an alternatively to TPU.

The reaction zone (62) has an inner diameter that is greater than the largest diameter of chamber (64) near the shoulder (70).

The particular dimensions of the throat is that the distance between the shoulder (70) is approximately 4.04mm and the diameter of the mouth (68) is about 6.4mm. The ! o greatest diameter of the chamber (64) near the shoul der (70) is 6mm while the thickness of the female component at (71) is about 1.8mm and the thickness of the female component at (73), in other words at the cap, is 1mm. As shown in Figure 7c alternative dimensions for the thickness around the chamber (64) can be used, such as 3.26mm on the outside at (81) and 3.86mm on the inside at (83). Many other combinations of 15 dimensions can be used.

It is to be understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the scope of the invention as defined in the appended claims.

Claims (13)

Received at IPONZ on 24 February 2012 The claims defining the invention are as follows:

1. A tag for attachment to an animal including: a penetrating component having a pair of spaced apart penetrating members 5 joined by an elongate intermediate portion at respective ends of the intermediate portion, each penetrating member having a stem extending outwardly from the intermediate portion and having a first end of the stem joined to the intermediate portion and a second end of the stem terminating in a penetrating head, the penetrating head having a distal point and a base forming a shoulder around the stem 10 of the penetrating member; a complementary component, separate from the penetrating component, having a pair of apertures arranged to receive respective penetrating members of the penetrating component so as to provide positive engagement of each respective shoulder of the penetrating heads with the complementary component; 15 each stem having a bore open at the first end to receive a respective pin of an applicator to assist in piercing the skin of the animal and positively engage the shoulders with the complementary component; wherein a section of material of the intermediate portion between each bore and a respective end of the intermediate portion is dimensioned so that there is no 20 overhanging part of the intermediate portion at each end of the intermediate portion to prevent the penetrating component being dislodged by the animal from the complementary component after positive engagement of the shoulders with the complementary component. 16 Received at IPONZ on 24 February 2012

2. A tag according to claim 1 wherein the intermediate portion has a pair of opposed sides that are substantially parallel to one another and extend directly between the sections of material.

3. A tag according to claim 1 wherein the intermediate portion has a pair of 5 opposed sides that each taper outwardly from the first and second ends to meet at a mid-point in each side.

4. A tag according to any one of the preceding claims wherein the stem of each penetrating member has a first section of larger diameter than a second section of the stem, such that the second section is adjacent the penetrating head and protrudes 10 through a respective aperture of the complementary component whereas the first section does not protrude through the respective aperture.

5. A tag according to claim 4 wherein the first section and second section of each penetrating member join at a transition area and the transition area abuts against a top surface of the complementary component around said pair of apertures. 15

6. A tag according to any one of the preceding claims wherein the penetrating heads of the penetrating members each have a pair of opposed flanges having a sharp edge terminating at the distal point of the head, to assist in piercing the skin of the animal.

7. A tag according to any one of the preceding claims wherein, in use, the 20 shoulder of each penetrating head are positioned in a locking engagement with the complementary component against a surface around a respective aperture of the complementary component to ensure that the penetrating head is unable to detach from the complementary component.

8. A tag according to any one of the preceding claims wherein the penetrating 25 component is integrally formed as a single unit. Received at IPONZ on 24 February 2012

9. A tag according to any one of the preceding claims wherein the complementary component is integrally formed as a single unit.

10. , A tag according to claim 8 wherein the penetrating component is made by an injection moulding process, 5

11. A tag according to claim 9 wherein the complementary component: is made by an injection moulding process.

12. A tag according to claim 3 wherein the distance between each mid-point is between 1 and 2 times greater than the distance between the sides on a line through the respective bore at each end and parallel to a line between each mid-point. 10

13. A tag for attachment to an animal substantially as hereinbefore described with reference to the accompanying drawing Figures 1 to 4. 18