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1. WO1993018370 - DISPOSITIF DE NIVELLEMENT

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

1. A levelling device comprising a casing having at least one exterior reference surface, and at least one light emitting element visible externally of the casing, the arrangement being such that, in use, if the reference surface or one of the reference surfaces is placed against a surface of an object, said at least one light emitting element provides a visual indication as to whether or not said reference surface is at a
predetermined angle to the vertical or horizontal.

2. A device as claimed in Claim 1, comprising an array of light emitting elements, a central one alone emitting light, in use, when said reference surface is at said predetermined angle.

3. A device as claimed in Claim 2, wherein as least a further light emitting element of said array, at one side of said central light emitting diode, emits light, in use, if said reference surface is not at said
predetermined angle.

4. A device as claimed in Claim 2 or Claim 3, wherein a signal or signals for the operation of the light emitting elements is or are produced by passing
electromagnetic radiation through a bubble vial from one side thereof and sensing the amount of electromagnetic radiation received at the opposite side thereof, the amount depending on whether it passes solely through liquid in the vial or through the bubble also, sensing means sensing said amount received producing said signal or signals.

5. A device as claimed in Claim 4, comprising two pairs of electromagnetic radiation emitters and sensors, one emitter and associated sensor being aligned axially of the vial and spaced axially therealong from the other emitter and associated sensor aligned axially of the vial by the axial extent of the bubble, so that when the device is at said predetermined angle to the vertical or horizontal the bubble is centrally positioned between the emitter/sensor pairs, and a balance signal is produced causing said central light emitting element alone to emit light.

6. A device as claimed in Claim 5, wherein an audio indication is produced each time the balance condition is reached.

7. A device as claimed in Claim 1, comprising a bubble vial, and means responsive to electromagnetic radiation for sensing at least one edge of the bubble of said vial, said at least one light emitting element being responsive to a signal or signals provided by the means responsive to electromagnetic radiation to provide said visual indication.

8. A device as claimed in any one of Claims 4 to Claim 7, comprising two of said bubble vials, disposed parallel and at 90° respectively to the or one reference surface, electromagnetic radiation being continuously passed through both vials during use of the device, with the bubble of the vial which is non-horizontal or
substantially non-horizontal during such use being clear of the area of said sensing so that said signal or signals are related solely to the position of said bubble of the other vial.

9. A device as claimed in Claim 8 , wherein each vial has, at one of its sides, a pair of axially spaced diodes for sensing said electromagnetic radiation, the diodes of one pair being electrically connected to the diodes of the other pair respectively in inverse parallel to maintain a low impedance .state for said diodes.

10. A device as claimed in any one of Claims 4 to 7, wherein at least one bubble vial is disposed in said casing so as to be visible externally thereof, and means are provided so that, in use, ambient light is not sensed in the production of said signal or signals.

11. A device as claimed in Claim 10, wherein to exclude the effect of ambient light the supply of said electromagnetic radiation is pulsed on and off at a high frequency and only the pulsed output of the sensing means responsive to electromagnetic radiation is used to provide said signal or signals.

12. A device as claimed in any one of the preceding claims, comprising a power supply and means for supplying power to an electrical circuit of the device from said power supply.

13. A device as claimed in Claim 12, wherein the power supply automatically ceases supplying power to said circuit after a predetermined period of time.

14. A device as claimed in Claim 13, wherein the time period is set by the capacitance of a capacitor which charges when the power is initially supplied to the circuit and thereafter discharges through a resistor.

15. A device as claimed in any one of the preceding claims, wherein the or each light emitting element is a light emitting diode.