Sensor For Locating Metallic Objects, And Measuring Device with Such a Sensor

• US 20080084212A1
• Filed: 11/21/2005
• Published: 04/10/2008
• Est. Priority Date: 01/18/2005
• Status: Abandoned Application

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Wieland, Christoph
• Application Number:
  US11/576,925
• Publication Number:
  US 20080084212A1
• Time in Patent Office: Days
• US Class Current: 324/329
• CPC Class Codes: G01V 3/107 using compensating coil or loop arrangements

Abstract

The invention relates to a sensor for locating metallic objects, especially an inductive metal sensor (110) for construction materials, said sensor comprising at least one emission coil (20) and at least one receiving conductor looping system (26) which are inductively coupled to each other. According to the invention, the at least one emission coil (20) is mounted in series with the primary side (30) of a compensation transformer (28). The invention also relates to a measuring instrument, especially a hand-held measuring instrument comprising one such sensor.

Claims

1. A sensor for locating metallic objects, in particular an inductive metal sensor (110) for building materials, having at least one transmission coil (20) and at least one reception conductor loop system (26) that are inductively coupled to each other,

wherein the at least one transmission coil (20) is connected in series with the primary side (30) of a compensation transformer (28).

2. The sensor as recited in claim 1,

wherein the numbers of turns of the primary side (30) and secondary side (32) of the compensation transformer (28) have the same ratio to each other as the numbers of turns of the transmission coil (20) and the reception conductor loop system (26).

3. The sensor as recited in claim 1,

wherein the compensation transformer (28) has a ferrite toroidal core (40).

4. The sensor as recited in claim 1,

wherein at least one winding system of the windings of the compensation transformer (28) is embodied in the form of a printed conductor strip structure on a printed circuit board.

5. The sensor as recited in claim 1,

wherein the compensation transformer (28) is embodied in the form of a printed transformer on a printed circuit board.

6. The sensor as recited in claim 1,

wherein the secondary side (32) of the compensation transformer (28) is connected in series with the reception conductor loop system (26).

7. The sensor as recited in claim 6,

wherein the secondary side (32) of the compensation transformer (28) is wound in the opposite direction from the winding direction of the reception conductor loop system (26).

8. The sensor as recited in claim 1,

wherein a subtraction circuit is provided, which subtracts the voltage U_E that is induced in the reception conductor loop system (26) and the voltage U_K that is detectable on the secondary side of the compensation transformer (28) from each other.

9. The sensor as recited in claim 1,

wherein magnetic fields in the frequency range of less than 1 MHz, preferably magnetic fields in the frequency range from 100 Hz to 200 kHz, are used.

10. A measuring device, in particular a hand-held locating device 210, having at least one sensor as recited in claim 1.