Dumpy level

Dumpy level
Automatic level in use on a construction site
Leveler for use by hand

A dumpy level, builder's auto level, leveling instrument, or automatic level is an optical instrument used to establish or check points in the same horizontal plane. It is used in surveying and building to transfer, measure, or set horizontal levels.

The level instrument is set up on a tripod and, depending on the type, either roughly or accurately set to a leveled condition using footscrews (levelling screws). The operator looks through the eyepiece of the telescope while an assistant holds a tape measure or graduated staff vertical at the point under measurement. The instrument and staff are used to gather and/or transfer elevations (levels) during site surveys or building construction. Measurement generally starts from a benchmark with known height determined by a previous survey, or an arbitrary point with an assumed height.

A dumpy level is an older-style instrument that requires skilled use to set accurately. The instrument requires to be set level (see spirit level) in each quadrant, to ensure it is accurate through a full 360° traverse. Some dumpy levels will have a bubble level ensuring an accurate level.

A variation on the dumpy and one that was often used by surveyors, where greater accuracy and error checking was required, is a tilting level. This instrument allows the telescope to be effectively flipped through 180°, without rotating the head. The telescope is hinged to one side of the instrument's axis; flipping it involves lifting to the other side of the central axis (thereby inverting the telescope). This action effectively cancels out any errors introduced by poor setup procedure or errors in the instrument's adjustment. As an example, the identical effect can be had with a standard builder's level by rotating it through 180° and comparing the difference between spirit level bubble positions.

An automatic level uses a swinging prism to compensate for small inclination deviations.

An automatic level, self-levelling level or builder's auto level, includes an internal compensator mechanism (a swinging prism) that, when set close to level, automatically removes any remaining variation from level. This reduces the need to set the instrument truly level, as with a dumpy or tilting level. Self-levelling instruments are the preferred instrument on building sites, construction and surveying due to ease of use and rapid setup time.

A digital electronic level is also set level on a tripod and reads a bar-coded staff using electronic laser methods. The height of the staff where the level beam crosses the staff is shown on a digital display. This type of level removes interpolation of graduation by a person, thus removing a source of error and increasing accuracy.

The term dumpy level endures despite the evolution in design.

See also

External links


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Look at other dictionaries:

  • Dumpy level — Dump y lev el (Surv.) A level having a short telescope (hence its name) rigidly fixed to a table capable only of rotatory movement in a horizontal plane. The telescope is usually an inverting one. It is sometimes called the {Troughton level},… …   The Collaborative International Dictionary of English

  • dumpy level — n. a surveyor s level with a telescope fixed to a spirit level that rotates in a lateral plane …   English World dictionary

  • Dumpy level — noun a surveyor s level having a short telescope fixed to a horizontally rotating table and a spirit level • Hypernyms: ↑surveyor s level * * * noun Etymology: dumpy (II) : a surveyor s level with a short usually inverting telescope that is… …   Useful english dictionary

  • dumpy-level — dumpˈy levˈel noun A surveyor s level with rigid connection of the telescope to the vertical spindle • • • Main Entry: ↑dumpy …   Useful english dictionary

  • dumpy level — noun Date: 1838 a surveyor s level with a short telescope rigidly fixed and rotating only in a horizontal plane …   New Collegiate Dictionary

  • dumpy level — Survey. an instrument consisting of a spirit level mounted under and parallel to a telescope, the latter being rigidly attached to its supports. [1830 40] * * * …   Universalium

  • dumpy level — /ˈdʌmpi lɛvəl/ (say dumpee levuhl) noun a surveying instrument consisting of a spirit level mounted under and parallel to a telescope, the latter being rigidly attached to its supports …  

  • Dumpy — may refer to: Dumpy level, an optical instrument used in surveying and building to transfer, measure, or set horizontal levels Dumpy s Rusty Nuts British rock band founded by Graham Dumpy Dunnell Scots Dumpy, a breed of chicken from Scotland… …   Wikipedia

  • Level — or levels may refer to: Contents 1 Places 2 Engineering related 3 Science and mathematics …   Wikipedia

  • Gavatt level — Dumpy level Dump y lev el (Surv.) A level having a short telescope (hence its name) rigidly fixed to a table capable only of rotatory movement in a horizontal plane. The telescope is usually an inverting one. It is sometimes called the {Troughton …   The Collaborative International Dictionary of English

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