Bar finder

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Bar finder; indicates steel pipe under a wooden plate

A beam finder , also known as a beam finder , is a device used to find wooden or metal beams in walls.

Types

There are main types of this device:

  • The first type uses a small magnet that detects nails or screws in the beam that were used to attach the wall during the making of the wall.
  • The second type uses an internal capacitor to detect changes in the permittivity (dielectric conductivity) of the wall as the user moves the device over the surface of the wall. A significant change in dielectric conductivity indicates a dense object behind the wall, usually a stud framing beam. Bar finders with an internal capacitor are very common.

Bar finders with an internal capacitor are divided into two classes:

  • Edge finders register the edges of the beam or other targets behind the wall. The sensor in an edge finder detects when it is directly over a change in density, like the edge of a bar. Edge finders must be moved across the wall from both the right and left to find both edges so that the center can be determined. The first bar finder with an internal condenser was an edge finder, and most budget models still are.
  • Center seekers recognize the center of the bar. These tools register the dielectric conductivity by means of several sensors and use the various readings to determine the position of the center of the target. Unlike edge finders, these bar finders only need to be moved in one direction to display the center of the bar. This type of bar finder is also called one step finder.

Internal capacitor bar finders can also have functions that allow them to find metal and live wires.

Development of models with an internal capacitor

The internal condenser bar finder was first designed by Robert Franklin in 1977. After patenting this device, he tried to sell the manufacturing rights to several large tool manufacturers, all of whom rejected the idea. He took his prototype to Zircon Corporation, an electronics manufacturer in Campbell , California , which agreed to manufacture and market the device. For the duration of the patent period (until 1998), Zircon was the only manufacturer of bar finders with internal capacitors. Then the patent expired and other companies were allowed to manufacture this device.

literature

  • Peter Barusche: Locating Devices : Search Engines . In: Self is the man . January 2010, p. 68–72 ( Selbst.de [PDF]).
  • Siegfried W. Best: Locating device: Bosch PDO Multi: With calibration-free inductive sensor . In: electronics industry . No. 8/9 , 2007, pp. 100-101 ( all-electronics.de [PDF]).
  • Peter Kübler: Drilling without surprise . In: The carpenter . No. 1/2011 , p. 14-15 ( hilti.de [PDF]).

Web links

Individual evidence

  1. ↑ Bo Hanus: The easy entry into mechatronics. Franzis Verlag, 2005, ISBN 978-3-7723-4604-0 , p. 169
  2. ^ Larry K. Baxter: Capacitive Sensors: Design and Applications . John Wiley & Sons, 1996, ISBN 0-7803-5351-X , p. 231