GB2162947A - Level - Google Patents

Abstract

A builders level having at least one levelling tube (2, 3, 4, 5) containing a leveling bubble (6), characterised by having a source of illumination (10, 11, 12, 13) adjacent the levelling tube to render the levelling bubble readily visible. The source of illumination is preferably optical fibres which transmit light from a light source (9) and terminate adjacent each levelling tube. <IMAGE>

Description

SPECIFICATION Level This invention relates to a level, used for determining horizontal, vertical and levelling at all angles in buildings and structures.

Levels generally comprise a straight member, which may be made of wood, plastics or .metal, and contain at least one tube partly filled by liquid so as to contain an air bubble.

When the tube is exactly horizontal, the bubble lies between two marks on the tube. A common type of level has three such levelling tubes, one coaxial with the straight member and approximately half way between its ends (for determining horizontal structures) and one tube at each end having their axes perpendicular to the axis of the straight member (for determining vertical structures).

Levels are frequentiy used in locations where there is inadequate lighting, for example inside partly completed buildings where there is no electricity supply, inside cupboards etc. In such locations it can be particularly difficult to see the bubbles in the levelling tubes. Indeed, it can sometimes be difficult to see these bubbles even in normal lighting, because of reflection of light from the tubes at particular angles. Attempts are made in practice to deal with this problem by holding a lighted match or a torch next to the levelling tubes. This involves the use of two hands instead of one, is particularly awkward in practice, and still does not enable the bubbles to be satisfactorily seen as the light source is not kept stationary with respect to the levelling tubes. An object of the present invention is to remedy this situation.

This invention provides a builders level having at least one levelling tube containing a levelling bubble, characterised by having a source of illumination adjacent the levelling tube to render the levelling bubble readily visible.

In a preferred aspect of the invention, the source of illumination is optic fibres which transmit light from a light source and terminate adjacent each levelling tube, the light from the end of the optic fibre being sufficiently concentrated to render the levelling bubble readily visible.

Reference is now made to the accompanying drawing which diagrammatically illustrates a preferred embodiment of the invention.

The level shown in the drawing comprises an elongated straight member 1 having four levelling tubes, 2 and 3 at each end and 4 and 5 in the middle. As in conventional levels, each levelling tube is partly filled with liquid so that it contains a levelling bubble 6 which, when the tube is exactly horizontal, lies between two marks 7 on the tube. The axes of the tubes 2 and 3 are perpendicular to the longitudinal axis of the member 1. Thus, when the bubbles in the tubes 2 and 3 are between the respective marks 7, then the member 1 is exactly vertical. The axes of the tubes 4 and 5 are parallel to the longitudinal axis of the member 1. Accordingiy, when the bubbles 6 in the tubes 4 and 5 are between the respective marks 7, then the member 1 is exactly horizontal.

An electrical power pack 8 is attached to the member 1. This powers a light source 9 which may be a conventional torch bulb, which is covered to concentrate the light into four optic fibres 10, 11, 1 2, 1 3 leading respectively to the levelling tubes 2, 3, 4, 5.

The optic fibres may be flexible piastics fibres of the kind manufactured by Mitsubishi Eska Extra EH4001. The optic fibres transmit light from the source 9 to the levelling tubes, and terminate adjacent the sides of the respective tubes so that the light emitted fcom the ends of the fibres, although faint, is perfectly sufficient to render the bubbles readily visible. An on/off switch can be incorporated in the power pack so that the source of illumination is only operative when the level is actually in use.

1. A builders level having at least one levelling tube containing a levelling bubble, characterised by having a source of illumination adjacent the levelling tube to render the levelling bubble readily visible.

2. A builders level according to claim 1, wherein the source of illumination is an optical fibre which transmits light from a light source and terminates adjacent the or each levelling tube.

3. A builders level substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Level This invention relates to a level, used for determining horizontal, vertical and levelling at all angles in buildings and structures. Levels generally comprise a straight member, which may be made of wood, plastics or .metal, and contain at least one tube partly filled by liquid so as to contain an air bubble. When the tube is exactly horizontal, the bubble lies between two marks on the tube. A common type of level has three such levelling tubes, one coaxial with the straight member and approximately half way between its ends (for determining horizontal structures) and one tube at each end having their axes perpendicular to the axis of the straight member (for determining vertical structures). Levels are frequentiy used in locations where there is inadequate lighting, for example inside partly completed buildings where there is no electricity supply, inside cupboards etc. In such locations it can be particularly difficult to see the bubbles in the levelling tubes. Indeed, it can sometimes be difficult to see these bubbles even in normal lighting, because of reflection of light from the tubes at particular angles. Attempts are made in practice to deal with this problem by holding a lighted match or a torch next to the levelling tubes. This involves the use of two hands instead of one, is particularly awkward in practice, and still does not enable the bubbles to be satisfactorily seen as the light source is not kept stationary with respect to the levelling tubes. An object of the present invention is to remedy this situation. This invention provides a builders level having at least one levelling tube containing a levelling bubble, characterised by having a source of illumination adjacent the levelling tube to render the levelling bubble readily visible. In a preferred aspect of the invention, the source of illumination is optic fibres which transmit light from a light source and terminate adjacent each levelling tube, the light from the end of the optic fibre being sufficiently concentrated to render the levelling bubble readily visible. Reference is now made to the accompanying drawing which diagrammatically illustrates a preferred embodiment of the invention. The level shown in the drawing comprises an elongated straight member 1 having four levelling tubes, 2 and 3 at each end and 4 and 5 in the middle. As in conventional levels, each levelling tube is partly filled with liquid so that it contains a levelling bubble 6 which, when the tube is exactly horizontal, lies between two marks 7 on the tube. The axes of the tubes 2 and 3 are perpendicular to the longitudinal axis of the member 1. Thus, when the bubbles in the tubes 2 and 3 are between the respective marks 7, then the member 1 is exactly vertical. The axes of the tubes 4 and 5 are parallel to the longitudinal axis of the member 1. Accordingiy, when the bubbles 6 in the tubes 4 and 5 are between the respective marks 7, then the member 1 is exactly horizontal. An electrical power pack 8 is attached to the member 1. This powers a light source 9 which may be a conventional torch bulb, which is covered to concentrate the light into four optic fibres 10, 11, 1 2, 1 3 leading respectively to the levelling tubes 2, 3, 4, 5. The optic fibres may be flexible piastics fibres of the kind manufactured by Mitsubishi Eska Extra EH4001. The optic fibres transmit light from the source 9 to the levelling tubes, and terminate adjacent the sides of the respective tubes so that the light emitted fcom the ends of the fibres, although faint, is perfectly sufficient to render the bubbles readily visible. An on/off switch can be incorporated in the power pack so that the source of illumination is only operative when the level is actually in use. CLAIMS

1. A builders level having at least one levelling tube containing a levelling bubble, characterised by having a source of illumination adjacent the levelling tube to render the levelling bubble readily visible.

2. A builders level according to claim 1, wherein the source of illumination is an optical fibre which transmits light from a light source and terminates adjacent the or each levelling tube.

3. A builders level substantially as hereinbefore described with reference to and as shown in the accompanying drawing.