The usual method is to shake the bottle and guess the quantity remaining. Often these predictions are incorrect and can cause inconvenience when the gas unexpectedly runs out.

There are a few simple gas measuring devices available on the market. They have been found to be impracticable and unreliable and as a consequence have had poor marketing success.

These devices include : A plastic strip which is adhered to the outside of the bottle. The gas level is indicated by a change in colour when boiling water is poured onto it.

A gauge fitted to the gas line with a red and green zone which is too small to accurately-predict gas-levels. The-cost of approximately $A40 also inhibits its marketing opportunity.

These problems are overcome by the present invention which consists of a cylindrical container with resilient chords attached to it and to the weighing plate.

The pointer attached to the plate indicates the gas level as it moves up and down vertically.

The advantage with this invention is that the design is simple, it is reliable and manufacturing costs are low.

The length and configuration of the resilient chords are designed so as to keep the overall height of the device as low as possible. This could be an important factor in situations where the height of the bottle on the weighing device is sometimes restricted as in the case with some domestic barbeques where the gas bottle is usually situated under the burners.

The gas level pointer may be attached or form part of the weighing plate. The weighing plate moves down as the load increases. The plate is at the lowest level in the cylindrical device when the gas bottle is full. The resilient chords attached to the weighing plate and the outside cylinder retract as the gas weight is reduced causing the gas level pointer to rise. The pointer is at the highest level on the measuring scale when the gas bottle is empty.

The elasticity of the resilient chords is in compliance with the manufacturers specifications. The tensile strength, elasticity and number of the chords will depend upon the load carrying capacity of the gas bottle weighing device.

The gas level pointer extends from the weighing plate through the slotted openings in the inner and outer walls of the invention. The pointer extends flush with the exterior surface of the outside cylindrical wall. The gas level pointer moves between the graduations on the outside cylindrical surface. Extra gas level pointers can be used at intervals around the outside cylinder for ease of reading.

The primary marketing target for this invention is to provide an ancillary utility for domestic barbeques. The squat design will allow for the bottle to remain seated on the weighing plate in the usual position beneath the barbeque cooking plates and burners so that the gas level can be readily checked at any time.

This invention can also be used for weighing other objects within the allowable weight scales.

In one form of the invention, the resilient chords consist of elastic rubber.

In its simplest form the gas bottle is placed on the weighing plate when it is empty and the pointer position is marked on the graduation scale. This empty position will be a permanent marking provided the same gas bottle is used. The scale is graduated in kilograms/lbs. When the full, or partly filled bottle is placed on the weighing plate the amount of gas remaining can be easily measured against the scale.

An alternative means of measuring the gas capacity is to mark on the scale the tare weight of the gas bottle. This weight is engraved on all certified gas bottles. When the gas level pointer rises to this marked position the gas bottle is empty.

The resilient chords may be of any cross-section and made of rubber, metal springs or any other elastic material. The springs can be enclosed in plastic tubing or other encasing so that the stretching movement is not restricted.

The invention maybe made from metal, moulded plastic or any other suitable material. The shape of the invention may not necessarily be circular in plan. The base of the invention will be mostly raised and provided with openings to allow easy egress of any water or material that may inadvertently enter the cylinders.

To assist in understanding the invention, reference will now be made to the accompanying drawings which show one example of the invention.

In the drawings: FIG. 1 shows one example of a gas bottle weighing device according to the invention.

It can be seen that the invention comprises elongated resilient chords 1 attached to the underside of the weighing plate 2 by a cir-clip or some other fixture. The resilient chords 1 passes over the smooth surface of the rounded surface 3 in the inner cylinder and fixed to the lower horizontal annular plate 4 attached to the inner and outer cylinders. The slots 5 are located at regular spacings around the perimeter of the inner cylinder. The configuration and length of the chords can be varied. In FIG. 1 the length of the chords 1 are shorter than those illustrated in FIG. 3. The length of the chord determines the extent of the elasticity and consequential degree of movement of the gas level pointer 8.

FIG. 3 shows the ideal configuration for resilient chords providing a longer length of chord and design configuration. This chord arrangement can be extended further if there is a need to increase the gas level pointer 8 movement.

In FIG. 4 one end of the gas level pointer 8 is fixed to the weighing plate. The gas level pointer extends through an opening in the inner cylinder wall 9 with the other end moving vertically along the graduation scale window 11 on the outer cylinder 10. The greater the degree of needle movement the easier it is to accurately read the quantity of gas remaining in the bottle.

Detail'A'on Plan No. RJB/01 shows the resilient chord arrangement over the rounded surface 3 in the slot. Alternatively, the chords may be guided by rotating wheels as shown on Detail'A'-ALTERNATIVE to assist the smooth elongation of the resilient chords. The chords are slightly tensioned when initially fixed at each end to ensure that the weighing plate exerts a slight upward pressure to the capping 6 lugs 7. This ensures that when all the weight is removed from the weighing plate it retracts back to the underside of the lugs.

The capping 6 clips onto the top of the inner and outer cylinder walls and is fixed in place by spring clips or similar attachments.

VIEW A on Plan RJB/02 shows the gas level pointer as seen on the outside cylinder.

This weighing device would be suitable for a gas bottle with a capacity of 4.5 kgs.

The gas bottle should be centrally located on the weighing plate. The outer area of the upper surface of the weighing plate can be painted with alternative colour rings to make it easy to centrally locate the bottle.