| 摘要 |
This invention relates to a self-contained and therefore portable battery powered levelling device. The device has a housing with at least one planar surface for placement on the surface to be levelled. The device contains a pendulum having an electrically conductive shaft and at least a set of four electrical contacts mutually arranged around and spaced from the pendulum's conductive shaft. Each of the electrical contacts is connected to a indicator light which is illuminated when the shaft makes electrical contact with one or more of the spaced contacts, thus providing an indication of an off-levelcondition. Furthermore, the device includes means for incrementally adjusting the distance between the electrical or conductive contacts and the conductive shaft of pendulum. The device also includes an audible indicator, such as a buzzer which may be selectively enabled to indicate an on-level condition. In a preferred embodiment of the invention, the levelling device includes a pair ofgravitational pendulums each associated with a pair of adjustable contacts arranged on either side of their respective pendulum. The two pendulums define a horizontal plane which is parallel to the base of the device such that an indication of a level base (or top) reflects the level condition.
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