GB2224839A

GB2224839A - Level-indicating device

Info

Publication number: GB2224839A
Application number: GB8924408A
Authority: GB
Inventors: Douglas Wade
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-11-10
Filing date: 1989-10-30
Publication date: 1990-05-16
Also published as: GB8826302D0; GB8924408D0

Abstract

In a level indicating device having a vial 8 containing a bubble 10, illumination means 18 are provided to facilitate viewing of the bubble 10 with respect to the reference marks 12. The illumination means 18 may be operated by a manual switch or a level-sensitive switch 22 and an over-ride or master switch may be provided. Timing means may also be provided to reduce the risk of inadvertent drain on a battery 20. <IMAGE>

Description

LEVEL-INDICATING DEVICE The invention is concerned with improvements in or relating to level indicating devices. The invention relates particularly but not exclusively to the type of indicating device commonly referred to by the term "spirit-level".

The type of level indicating device in conventional use by "do-it-yourself" handymen or in the construction industry commonly comprises a body member including at least one straight-edge at a lower surface thereof in use, and, at an upper surface thereof, at least one recess in which is positioned a sealed capsule or vial partially filled with a liquid so as to leave a bubble.

Conveniently such a liquid may be coloured. The vial is elongate and presents a general convex surface to the viewer, the bubble rising to the highest point of the convex surface at whatever orientation the device is positioned in use. Reference marks on the vial surface indicate where the bubble will be situated whenever the vial, and therefore the level indicating device, is in an exactly horizontal orientation. Many such devices also incorporate a means for indicating accurate vertical orientation.

However, it is often difficult, due to inaccessibility of working areas or poor levels of illumination, to view the vial reference marks or the bubble in the liquid.

The invention provides a level indicating device comprising a body portion including at least one planar surface adapted to be placed on, or in substantial contact with, a surface the horizontal or vertical orientation of which is to be checked or adjusted, said device further comprising a vial mounted in a recess in the body portion, said vial having an upwardly facing convex wall and containing a sufficient quantity of liquid sealed therewithin to form a bubble, wherein there are provided means within the body portion to illuminate the recess in which the vial is mounted.

Preferably the illumination means is a light bulb or other small light-emitting device such as a light-emitting diode (L.E.D.), operable from a battery or power source by means of a switching means.

Conveniently the switching means may comprise a manually operated switch. Advantageously, for example in the case of a horizontal level indicating device, the switching means may, when energised, operate automatically by means of a level-sensitive device such as a mercury tilt switch, as an indication that a horizontal or near-horizontal orientation has been at least approximately achieved, to enable fine adjustment of horizontality to be made under improved viewing conditions.

There will now be described an example of a device according to the invention. It will be understood that the description, which is to be read with reference to the drawing, is given by way of example only and not by way of limitation.

The drawing shows a sectional view through a level indicating device according to the invention and adapted to indicate horizontal orientation.

A body portion 2 of the device is provided with a lower surface 4 which is accurately planar and adapted to be positioned upon a substrate, the horizontality of which is to be checked. A recess 6 is formed in the body portion 2 in which is mounted a curved vial 8 containing liquid 7 and entraining a bubble 10. As in conventional devices of this kind, the location of the bubble between two reference marks 12 in a viewing aperture 14 formed in a recess covering plate 16, indicates that the device is level with the horizontal and therefore the substrate is "level".

A bulb 18 is provided below the central portion of the vial which, when lit, assists in the viewing of the relationship between the bubble 10 and the reference marks 12. The bulb is powered by a battery 20 and, in the present example, is operated by a mercury tilt switch 22 in which the associated circuit 24 is only able to be completed when the device is in a position at least approaching horizontal. A master switch (not shown) may be used to render the circuit inoperative when the device is not in use or operative irrespective of orientation of the device.

If desired, the device may also be provided with a timing device (not shown) which operates after the elapse of a desired period of time to render the circuit inoperative and avoid unnecessary drain on the battery 20.

Various modifications may be made within the scope of the invention as defined in the following claims.

Claims

CLAIMS:

1. A level indicating device comprising a body portion including at least one planar surface adapted to be placed on, or in substantial contact with, a surface the horizontal or vertical orientation of which is to be checked or adjusted, said device further comprising a vial mounted in a recess in the body portion, said vial having an upwardly facing convex wall and containing a sufficient quantity of liquid sealed therewithin to form a bubble, wherein there are provided means within the body portion to illuminate the recess in which the vial is mounted.

2. A device as claimed in claim 1, wherein the illumination means is a light bulb.

3. A device as claimed in claim 1, wherein the illumination means is a light emitting diode.

4. A device as claimed in either one of claims 2 and 3, wherein the illumination means is operated by a manually operated switch means.

5. A device as claimed in either one of claims 2 and 3, wherein the illumination means is operated by a level sensitive switching means, the construction and arrangement being such that the illumination device is operated only when the desired horizontal or vertical orientation is at least approximately achieved to act as an indication prior to fine adjustment of the substrate orientation.

6. A device as claimed in claim 5, wherein the switching means is a mercury tilt switch.

7. A device as claimed in any one of claims 4 to 6, wherein there is further provided an over-ride or master switch to render circuitry associated with the illumination means inoperative when the device is not in use.

8. A device as claimed in claim 7 insofar as it is dependent on claims 5 and 6, wherein the over-ride or master switch is capable of rendering the illumination means operative irrespective of the orientation of the device.

9. A device as claimed in any one of the preceding claims wherein timing means are provided in association with the illumination means so as to cease operation thereof after the lapse of a predetermined period of time.

10. A level indicating device, constructed and arranged substantially as hereinbefore described with reference to and as shown in the drawing.