Plumb bob

A Lot ( also plumb, plumb, plumb or plumb bob ) is a tool to determine the vertical.

A traditional solder consists of a symmetrical metal part (lead) that is attached to a thin cord. For higher accuracies there own Lotinstrumente, and for the measurement of zenith distances, the built- in theodolite dragonflies or Lotsensor ( compensator ).

In construction and renovation work, such as wallpapering, the plumb line is often provided with colored chalk dust to highlight by plucking the taut plumb vertical lines on walls ( see chalk line ).

Construction

The metal piece is ideally of high specific gravity ( " hard " ), it was formerly made up lead. The reason for this is the lower sensitivity to air currents, but also means a slower attenuation of an initial unintended movement of the solder. Version: pointed and round, sometimes cylindrical. Axisymmetric of the cord attachment to the tip, which serves as a pointer under the anchorage. The attention drawn by the metal piece of string runs exactly along the vertical. With a longer plumb base points can be abgelotet, but today usually done visually.

Geodesy

In geodesy, the solder used to centric setting up of older theodolites and ranging poles on the measurement points, surveying or fixed points. Newer devices have to perform this operation a range pole, an optical plummet or laser plummet.

• The range pole
• The plumb bob is now rarely in use. Previously it was used by almost all of the ranging pole set up perpendicular to the instrument tripod. The cord solders used are made ​​of iron or brass, pear-shaped or oblong, 200-500 grams in weight and have a Lotschnurlänge of approximately 2.5 meters.
• The optical plummet is an additional device for accurate centering of the measuring instrument over a ground point. It can be prepared as a separate instrument, to be installed in a tripod or theodolite. One located in the eyepiece of the solder target is deflected on a Umschaltprisma exactly to the zenith or nadir for and brought to the ground point (or a zenith point ) to cover.
• The laser plummet is an independent accessories. It replaces the optical plummet by a laser beam. The brightness of the laser is adjustable, a built- tube level enables precise leveling of.

The rough leveling of the instrument is done with the circular bubble and the fine leveling with the tubular level.

Centering accuracy of the individual Lotarten ( With zero wind and 1.5 m instrument height ):

• Range pole: 1.0 ... 2.0 mm
• Plumb: 3.0 ... 5.0 mm
• Optical plummet: < 0.5 mm
• Plummet: <0.8 mm ( with a laser diameter of 2.5 mm)