GB2399635A

GB2399635A - Illuminated spirit level

Info

Publication number: GB2399635A
Application number: GB0304929A
Authority: GB
Inventors: Robin William Thatcher
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-03-05
Filing date: 2003-03-05
Publication date: 2004-09-22
Also published as: GB0304929D0

Abstract

A spirit level comprises light emitting diodes to illuminate vials 3 and an electrical power supply. The electrical power supply comprises a dynamo generator which is driven manually via a rotatable handle 4. The rotatable handle may be folded away such that it does not extend beyond the body of the level or alternatively the handle may be detachable. The body of the level houses a rechargeable storage cell coupled to the generator. A switch to turn the light emitting diodes on and off further includes a time delay feature arranged to break the battery circuit after a predetermined time interval. The dynamo generator, storage cell and switch may be constructed as a single sealed water resistant unit. The device incorporates a generator to reduce problems associated with battery deterioration.

Description

ILLUMINATED SPIRIT LEVEL

This invention relates to an illuminated spirit level. It relates particularly to a builders spirit level which carries its own light source to enable the necessary visual reading to be made by a user even when the instrument is needed in a dark corner.

A spirit level is usually only used infrequently by the amateur or professional builder and often this use is required in a corner or place where the natural lighting is low.

T here can therefore be a difficulty found in observing the reading of the level indication given by the glass vials of the instrument. There have already been proposals to provide the spirit level with its own light source such as a light-emitting diode (LED) device with a dry battery power supply. One example of this construction is disclosed in patent

specification Not GB2371863.

Whilst a battery powered spirit level having glass vials illuminated by LED devices can be a robust and useful instrument, there is the usual problem that the battery can become discharged even when the instrument is not being used. With an instrument that is only being used infrequently like the spirit level, this can mean that if it is used and then put aside for a few weeks, then next time it is required for use the battery will be found to have become discharged. This situation can be irritating to the user particularly since a battery can leak a corrosive fluid material when allowed to remain in a discharged condition.

I have now found an alternative construction of spirit level which has LED illumination and which enables the problems associated with battery shelf life deterioration to be reduced. This can enable the construction of a spirit level which is quickly made ready for use even after it has been laid aside for a several weeks.

According to the invention, there is provided a builders spirit level having one or more vials with LED device illumination, in which an electrical power supply unit for the light source includes a manually operable dynamo generator. The generator may be operated by means of a rotatable handle. The handle may be arranged to fold so that when folded it does not extend much beyond a basic body outline of the spirit level. A recess may be provided in a body of the spirit level to accommodate the said handle when the handle is out of use.

In a different embodiment, the handle may be made to be detachable from a generator drive shaft.

Preferably, the spirit level includes a rechargeable storage cell which is coupled to the generator. The spirit level may include an ON/OFF switch arranged to control operation of the LED devices. The switch may have a time delay feature arranged to move the switch contacts to an OFF position after a predetermined time interval. An operating button for the switch may be located in a recess on the spirit level body.

By way of example, a particular embodiment of the invention will now be fu ther described with reference to the accompanying drawings, in which: Figure 1 is a front view of the spirit level, Figure 2 is a top view, Figure 3 is a rear view, Figure 4 is a view from one end, and, Figure 5 is an electrical circuit diagram.

As depicted in Figure 1, the spirit level 1 is of a conventional shape having a hollow rectangular body 2 with three transparent glass vials 3. Each vial 3 is provided wi h its own LED illumination device (not shown). The spirit level front side includes a vet,.der l andlc 4 which is located directly on a drive shaft of a dynamo generator ac omrnodated within the body 2.

Figure 2 is a top view from which can be seen one of the glass vials 3 located on an upper edge of the spirit level. The handle 4 on the front of the body 2 is also shown.

Figure 3 is a rear view. This shows a flexible membrane 6 mounted on the side of the spirit level. The membrane 6 is located over a Push On/ Push Off type of switch which is accommodated within the body 2 so that a switch operating button will be protected against the entry of water or dust.

I:igure 4 is an end view.

To igure 5 is a simple electrical diagram which shows that the electrical power supply is provided by an output coil 7 of the dynamo generator which is connected across the terminals of a rechargeable storage cell 8. In turn, the storage cell 8 is arranged to power three LED devices 9 when a switch 11 has been closed. The switch 11 is located beneath the membrane 6 on the body 2.

In use of the spirit level, this can just be taken in the hand by the builder and the generators handle 4 can be given a few turns in order to charge the storage cell 8. The spirit level can then be placed on, for example, a picture frame edge the horizontal correctness of which is required to be checked. The builder can then press the switch operating button on the body of the spirit level this button being located beneath the membrane 6 and the three vials 3 ill become illuminated by their built-in LED devices 9. The builder will be able to inspect immediately the relevant vial to enable the reading to be noted. The vial reading can be seen easily even if the spirit level should be used in a dark corner. After having been bright for a predetermined number of seconds, the time interval function will operate to open the switch 11 and break the LED device circuit. This will cause the devices 9 to go dark. They may be illuminated again when required by a renewed pressure on the switch operating button.

The spirit level can be used to make further readings during the course of some hours before it becomes necessary to put another charge into the storage cell. After use, the instrument may be put aside and it can then be used later in a reliable manner because the construction has avoided the use of a battery storage device which has only a limited shelf life.

The spirit level of the invention has been found to be comparatively inexpensive to construct and it can enable a robust instrument to be made with an extremely reliable light source. The dynamo generator used for the construction can be similar to those available at present in some portable radio receivers. Since the storage cell is intended to be a permanent part of the instrument construction, this can be a higher quality component that the ordinary disposable battery. The risk of any accidental escape of liquid from the cell can thus be substantially reduced. Even if the spirit level has been put aside with other tools in a builders tool bag, the level can be expected to work well when it is next required because the use of fragile and prematurely ageing components have been excluded from the construction.

The main spirit level components of the dynamo generator, the storage cell 8 and the switch 11 may conveniently be constructed as a single sealed water resistant unit. This can enable the spirit level to be made in a very robust form so that it will be able to tolerate rough handling and the presence of some moisture which are the conditions that might be expected in an area where building work is being done.

The foregoing description of an embodiment of the invention has been given by way of example only and a number of modifications may be made without departing from the scope of the invention as deemed in the appended claims. For instance, instead of being located directly on the generator shaft, the handle may be arranged to drive the shaft indirectly through a gearing mechanism.

Claims

Claims 1 A builders spirit level having one or more vials with LED device

illumination, in which an electrical power supply unit for the light source includes a manually operable dynamo generator.
2 A spirit level as claimed in Claim 1, in which the generator is operable by means of

a rotatable handle.
3 A spirit level as claimed in Claim I or 2, in which the handle is arranged to be foldable so that when folded it does not extend much beyond a basic body outline of the spirit level.
4 A spirit level as claimed in Claim 2 or 3, in which a recess is provided in a body of the spirit level to accommodate the said handle when the handle is out of use.
A spirit level as claimed in Claim 1, in which the dynamo generator has a drive shaft to which a detachable handle may be connected.
6 A spirit level as claimed in any one of Claims 1 to 5, in which a body of the level houses a rechargeable storage cell coupled to the generator.
7 A spirit level as claimed in any one of Claims 1 to 6, in which a spirit level body includes an ON/OI7F switch arranged to control operation of the LED devices.
8 A spirit level as claimed in Claim 7, in which the switch has a time delay feature arranged to break the battery circuit to the LED devices after a predetermined time interval.
9 A spirit level as claimed in Claim 7 or 8, in which an operating button for the switch is located in a recess on the spirit level body.

A spirit level substantially as hereinbefore described with reference to the accompanying drawing.