AU2007231855B2 - Marking device - Google Patents

Abstract

MARKING DEVICE A bowl marking device suitable for use in lawn bowls consisting of a body member having a hollow elongate chamber adapted to house a chalk stick, and having an upper and lower opening, the upper opening being adapted to allow the chalk stick to protrude upwards from the upper opening, an adjustable means for adjusting the 10 longitudinal movement of the chalk stick within the body member so that, in use, the chalk stick end may be adjusted to extend beyond the upper opening of the body member, a sealing means adapted to seal the upper opening of the body member, wherein the sealing means is in the form of a cap with a top and circumferential walls that provide a vapour sealing fit to the body member when located over the upper opening, and wherein the chalk 15 stick is formed in situ in the body member and wherein the chalk stick is prepared by combining an aqueous slurry comprising a settable chalk powder, a water miscible volatile solvent, water and an essential oil.

Description

AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION INVENTION TITLE: MARKING DEVICE The following statement is a full description of this invention, including the best method of performing it known to me:- MARKING DEVICE Field of the Invention This invention relates to a marking device for applying an erasable or removable mark to objects, especially bowls. 5 Background of the Invention Lawn bowls is an international sport with many participants throughout the world. The majority of participants live in Commonwealth countries such as England, Scotland, Wales, Ireland, Australia, New Zealand and South Africa. In the sport of lawn bowls the rules provide that in certain situations it is 10 necessary to mark a bowl. The most common situation is where a bowl contacts the jack after the bowl is bowled. To distinguish this bowl from the other bowls that have not contacted the jack, an indicator mark is applied to the surface of the bowl. As the bowl will be used on the next end or in a further game, it is important that the mark be easily removable or erasable. On the other hand, the mark is required to have sufficient 15 mechanical integrity or be sufficiently adherent so that the marked bowl will retain its mark after the marked bowl has been rolled and moved over the green and into the ditch. Two methods of marking bowls are conventionally used. The first method involves using a chalk stick. To improve the adherence of the chalk mark, some bowlers moisten the chalk end with their saliva. This can obviously lead to hygiene problems and 20 the potential transmission of bacteria and viruses from bowler to bowler. The second method involves the use of an aerosol container within which is a pigment combined with a binder and a propellant. Propellants are typically hydrocarbons or halogenated hydrocarbons and their use can cause problems for the users. A further problem is that the propellant is flammable and transport on aircraft can be inconvenient. 25 Additionally, the aerosol markers are relatively expensive based on the number of uses one can obtain from an aerosol pack. Typically only a hundred or so uses are obtained from the one pack. It would be desirable to have a marking device that overcame some of the problems associated with the prior art markers, particularly bowl markers. 30 Summary of the Invention This invention provides in one form a bowl marking device comprising: a body member having a hollow elongate chamber adapted to house a chalk stick, and having an upper and lower opening, the upper opening being adapted to allow the chalk stick to protrude upwards from the upper opening, an adjustable means for adjusting the longitudinal movement of the chalk stick within the body member so that, in use, the chalk stick end may be adjusted to extend beyond the upper opening of the body member, a sealing means adapted to seal the upper opening of the body member, 5 wherein the sealing means is in the form of a cap with a top and circumferential walls that provide a vapour sealing fit to the body member when located over the upper opening, and wherein the chalk stick is formed in situ in the body member and wherein the chalk stick is prepared by combining an aqueous slurry comprising a settable chalk powder, a water miscible volatile organic solvent, water and an essential oil. 10 Preferably, the body member is in the form of a hollow cylinder. Preferably, the adjustable means comprises a rotatable member that is adapted to seal the lower opening of the body member and to move the chalk in a longitudinal direction by rotation of the rotatable member. Preferably, the essential oil is tea tree oil. 15 Preferably, the water miscible organic solvent is ethanol. Preferably, the chalk stick ingredients are (w/w): settable chalk powder 30 - 50% water 30-50% ethanol 5- 15% 20 tea tree oil 0.5 - 2% Brief Description of the Drawings Figure 1 is a cross-sectional view of a marking device according to the invention. Detailed Description of the Invention 25 The invention will be further described by reference to a preferred embodiment illustrated in the accompanying drawing. Referring to Figure 1, the bowl marking device I consists of hollow cylindrical body member 2 with upper and lower openings 3,4. Disposed within the body member 2 is a chalk stick 5 which is located on a plate 6. The plate 6 is affixed to the upper end of a 30 helical externally threaded rod 7. The threaded rod 7 is located in a rotatable tube 8 with a mating internal thread 16. The rotatable tube 8 has an annular flange with peripheral slots (not shown) which engage in longitudinal spine members 9 located in a rotatable bottom member 11. The upper end 3 of the body member 2 is sealable by a removable cap 12. The sealing is improved by an annular protrusion 13 on a neck portion 14 of the body member 2. The walls of the cap 12 and body member 2 are typically made of plastic and have some small amount of deformation such that a moisture seal is provided with the annular protrusion 13 when the cap 12 is pushed onto the neck portion 14. The cap 12 is shown above a sealed position and would need to be lowered to form a seal. 5 The chalk stick 5 may be propelled upwards by rotation of the rotatable bottom member 11 in one direction, and it may be retracted by rotation in the opposite direction. The plate 6 has two circumferential opposed recesses that slidably fit into a pair of longitudinal protrusions 15 that are formed integrally with the body member 2. The apparatus described above for moving the chalk stick are known from other uses, such as 10 lip balm applicators. It will be appreciated that there are various modifications of this apparatus that may be made. For example, simpler mechanisms as used for glue sticks may be used. In its simplest form, the apparatus could dispense with the use of a mechanism for moving the chalk stick and simply have a fixed chalk stick. Preferably the adjustable means for adjusting the longitudinal movement of the 15 chalk stick within the body member is adapted to form a vapour seal of the lower opening. The chalk stick is prepared in situ by forming an aqueous slurry of settable chalk powder, water and an ethanolic solution of tea tree oil. In a preferred composition the weight ratios of the settable chalk powder, the water and the ethanolic solution of tea tree oil is 4:4.4:1. The ethanolic solution of tea tree oil is preferably 20% w/w. This 20 provides a weight ratio of settable chalk powder, water, ethanol and tea tree oil of 20:22:4:1. The chalk stick sets in a matter of minutes. It may take several hours to cure and is slidable within the body member 2 by rotation of the rotatable bottom member 11. The term "essential oil" has its ordinary technical meaning as in Hawley's Condensed Chemical Dictionary (Twelfth Edition) and is "a volatile oil derived from 25 leaves, stem, flower or twigs of plants, and usually carrying the odours or flavours of the plant. They are often prepared by steam distillation but may also be prepared by pressing, solvent extraction or other techniques. Examples are tea tree oil, eucalyptus oil, lavender oil, lemon oil, orange oil, peppermint oil and rosemary oil. Especially preferred is tea tree oil. This oil has been found to have anti-bacterial and preservative properties as well as a 30 pleasant odour. Suitable tee tree oil is available from Eureka Oils as a 20% solution in ethanol. The settable chalk powder is of known kinds and, in a preferred form, usually consists of a mixture of calcium carbonate and plaster of Paris. Plaster of Paris is calcium sulfate. These powders are settable by the addition of water to form a pourable slurry.

-5 However, other binding agents may be used provided the chalk is settable by the addition of water. The water miscible volatile organic solvent is preferably a lower alkyl alcohol, and more preferably ethanol. The solvent is regarded as volatile if the 5 solvent evaporates to a substantial extent after the mark has been applied. The relative proportions of the settable chalk ingredients contributes to the physical and mechanical properties of the chalk stick. The chalk stick is prepared in situ by pouring a slurry of the chalk stick ingredients into the body member 2 with the plate 6 in the lowest position. After the 10 chalk stick has set and cured, it may be moved upwards and used to mark objects. In use, it has been found that the marking device can be used many times for marking bowls, sometimes in excess of one thousand times. One of the benefits of the marking device according to the present invention is that the mark may be easily applied. The mark develops or becomes more conspicuous and opaque after a 15 few seconds. This is believed to be due to an effect known as "dry hiding" on the evaporation of the volatile components of water and ethanol. While the marking device of the present invention is primarily intended for marking lawn bowls, it has a number of other applications. An example is the marking of glass. One of the features of the marking device of the present invention 20 is that the mark is removable by the application of friction from a hand or a cloth. It thus provides a temporary mark which is easily removed when no longer required. 02/09/10jb16161 pages 5 & 7.doc,5

Claims (7)

1. A bowl marking device comprising: a body member having a hollow elongate chamber adapted to house a chalk 5 stick, and having an upper and lower opening, the upper opening being adapted to allow the chalk stick to protrude upwards from the upper opening, an adjustable means for adjusting the longitudinal movement of the chalk stick within the body member so that, in use, the chalk stick end may be adjusted to extend beyond the upper opening of the body member, 10 a sealing means adapted to seal the upper opening of the body member, wherein the sealing means is in the form of a cap with a top and circumferential walls that provide a vapour sealing fit to the body member when located over the upper opening, and wherein the chalk stick is formed in situ in the body member and wherein the chalk stick is prepared by combining an aqueous slurry comprising a settable chalk powder, a water 15 miscible volatile solvent, water and an essential oil.

2. A bowl marking device as defined in claim I wherein the adjustable means for adjusting the longitudinal movement of the chalk stick within the body member is adapted to form a vapour seal of the lower opening. 20

3. A bowl marking device as defined in claim I or claim 2 wherein the chalk stick is prepared by forming an aqueous slurry wherein the water miscible volatile solvent is ethanol and the essential oil is tea tree oil. 25

4. A bowl marking device as defined in claim 3 wherein the aqueous slurry comprises (w/w): settable chalk powder 30 - 50% water 30 - 50% ethanol

5- 15% 30 tea tree oil 0.5-2% 5. A bowl marking device as defined in claim 4 wherein the weight ratios of settable chalk powder, water, ethanol and tea tree oil is approximately 20:22:4:1. -7

6. A bowl marking device as defined in any one of claims 1 to 5 wherein the settable chalk powder comprises a mixture of calcium carbonate and plaster of Paris.

7. A bowl marking device substantially as herein described with reference to 5 the accompanying illustration. 02/09/10jb16161 pages 5 & 7.doc,7