This invention relates to levels and in particular to water levels.

A water level can comprise a length of plastics tubing with at either end a cylindrical glass or plastics container attached to the tubing. The glass or plastic cylinders are translucent or transparent enabling the water in the tubing to be viewed.

As is well established water will find its own level and therefore water placed in the tubing will enable a user of the level to transfer water level across large distances. At present a datum is used which is marked onto a surface eg a wall of a building. This datum is then used to establish other levels in the building or on the adjacent site. By using the water level it is possible to transfer the datum from place to place by taking the cylinders to the datum and bringing the water level in line with the datum.

At present two people are required to operate such an arrangement with the exception of an electronic water level which is

available. One person holds one of the cylinders to the datum and without moving that cylinder instructs the other person to raise or lower the end of the tubing which they are holding until the water in the cylinder of the first person is in line with the datum. The person at the datum then gives instructions for the other person to mark off the level at their end of the device to the building surface with a marker such as a pencil. The two marks, the original datum and the marked level just placed on the surface should be at exactly the same level.

Certain problems are encountered in the levelling using such a device. Confusion often arises as to whether the person holding the free end of the device should be either raising or lowering their end of the level. In other words the person giving the instructions sometimes gets confused as to the direction that the other person needs to be moving their cylinder. The level is quite commonly used in a noisy environment such as a building site when levels are being struck so that shouted instructions are not heard or misheard and inaccuracy is often the result even after a lot of careful preparation.

If after the water level has been brought in line with the datum and the cylinder is moved inadvertently at the datum a wrong mark will be struck on the building surface. Accumulation of errors is inevitable if a considerable amount of levelling is to be done. The reason for this is that once the full length of the

tubing has been exhausted the person at the original datum will have to move to a datum which has been previously struck by his partner. A wrong mark struck on the later established datum will then be transferred elsewhere and errors will accumulate.

The present invention seeks to provide a water level which can be used by one person to transfer levels accurately from a datum over a range of distances.

Accordingly the present invention provides a water level comprising a flexible housing containing water, the housing having at each end a transparent portion, each end of the housing having closure means to prevent escape of water, one end of the housing being attachable to a structure and the other end having two adjustable markers adjacent to the transparent portion, the markers being settable to indicate a water level and a datum to be transferred.

The flexible housing may comprise a length of plastics tubing.

The transparent portions may comprise toughened glass or plastics cylinders connected to the ends of the tubing and having open ends, which can be closed with screw tops when the level is not in use.

The closure means can comprise a valve to close off the open ends

of the cylinders, when the level is in use.

The valves can comprise a ball located in a cage.

The glass or plastic cylinders can each be mounted on a back plate, one of which can be secured to structures eg walls or other parts of a building by means of, for example, screws, nails or hooks.

The markers can each comprise a bolt and screw located in a slot in one of the backplates.

The present invention will now be more particularly described with reference to the accompanying drawings in which:

Fig. 1 shows a diagrammatic elevation of one end of one form of water level according to the present invention and

Fig. 2 shows the other end of the water level shown in Fig. 1.

Referring to the drawings a water level 10 comprises a length of plastics tubing 12. Glass or plastics cylinders 14 and 16 are attached at each end of the tubing 12 and these cylinders are secured to mounting plates 18 and 20 respectively. The cylinders 14 and 16 have openings 14A and 16A respectively at their ends and these openings can be closed off by ball valves 20 and 22. The ball valves each comprise a ball 20A and 22A mounted in a

cage 20B and 22B, respectively.

The mounting plate 18 has an opening at its upper end enabling the plate to be secured to part of a building, for example by means of a screw 26.

The other mounting plate 20 has a slot 28 in which two screw and nuts assemblies 30 and 32 are slideably located. The assembly 30 is used to mark a water level and the assembly 32 is used to mark a datum level.

When the level is not in use, the ends of the cylinders 14 and 16 can be closed off by screw tops 34 and 36.

In use, the screw tops 34 and 36 are removed, the tubing 12 and cylinders 14 and 16 are filled with water or a similar liquid leaving approximately half of each cylinder empty. It will be appreciated that in use the valves 22 and 24 will prevent water escaping from the level but the presence of the openings 14A and 16A allow the escape of air and the water to move within the level.

It will be appreciated that it is difficult, if not impossible to drill a hole positioned accurately in material with obstacles, ie, concrete or brick under plaster. The provision of the two marker assemblies 30 and 32 allows the plate 18 to be fixed

approximately in position, as will be described below.

The mounting plate 18 is therefore attached to part of a building eg a wall by means of the screw 26 approximately in position relative to the datum to be transferred. The other plate 20 is brought adjacent the plate 18 and the mounting plate 20 is moved so that the water in each cylinder 14 and 16 is at the same level. The assembly 30 is then moved until it is aligned with this water level and is locked in position in the slot 28.

The assembly 32 is then moved in the slot 28 until, it is on a level with the datum which is to be transferred.

The operator moves the plate 20 to the location to which the datum is to be transferred, the plate 18 being left secured in position by means of the screw 26.

The operator then moves the plate 20 in a vertical direction until the water level in the cylinder 16 is adjacent the marker assembly 30. The plate 20 is maintained in this position and a mark can then be placed adjacent the datum assembly 32.

The datum thus marked will be the datum transferred from the location of the mounting plate 18.

The operator can then move around the building or site and

transfer the datum to other positions within the building or site, depending upon the length of tubing 12 available.

If a level to be struck is further away from the original datum than the length of the tubing 12 will allow then one of the transferred levels can be used which is nearer the level to be struck and within the length capability of the tubing 12.

It will be clear that the level can be used by one person to transfer a datum in an accurate manner. Also the level will not spill or lose water because of the valves 22 and 24, and the screw tops 34 and 36 prevent the loss of water when the level is not in use.

The present invention is a simple mechanical device and does not rely on electricity or electronics.

The labour time and cost will be considerably reduced and it is easier and quicker to transfer a datum.

A water level according to the present invention will also considerably reduce the margin of error involved in transferring the datum.

It will also allow the operator to obtain access to most locations in a building or on a building site without reliance

on a second person eg up step ladders or on scaffolding.

The level once filled with water and fixed into position could be kept in use over and over again instead of, as is the present practice, of being put away and reluctantly being used again.