Differential Hall-effect gear measure feeler

• US 4,703,261 A
• Filed: 12/11/1984
• Issued: 10/27/1987
• Est. Priority Date: 12/15/1983
• Status: Expired due to Fees

• Current Assignee: MAAG Gear-Wheel & Machine Company Limited
• Original Assignee: MAAG Gear-Wheel & Machine Company Limited
• Inventors: Berchtold, Nikolaus
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Snow, Walter E.
• Application Number:
  US06/680,363
• Time in Patent Office: 1,050 Days
• Field of Search: 324/207, 324/208, 324/251, 338/32 H, 33/558, 33/561, 307/309
• US Class Current: 324/207.2
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

The measuring system of the gear measuring feeler contains, as a Hall-effect sensor, two Hall-effect sensor elements which are arranged in opposing relationship to each other in the magnetic field. The differential output signal of this dual Hall-effect sensor is processed in a matching circuit which is designed as a differential amplifier circuit, to yield a measuring voltage with respect to zero volt. This measuring voltage is twice as high as in the case where only one Hall-effect sensor element is used as the Hall-effect sensor. Furthermore, the matching circuit is of a simpler structure and the measurement is substantially more precise since there is not required any reference voltage source in the matching circuit.

Claims

1. A gear measuring feeler comprising:

a housing;

a feeler rod pivotably mounted in said housing and deflectable from a predetermined position;

said feeler rod having a first end and a second end;

a feeler probe provided at said first end of said feeler rod;

a measuring system comprising two members which are movable relative to each other;

one of said two members being supported at said second end of said feeler rod;

said two members comprising means for generating a static magnetic field and a Hall-effect sensor;

said Hall-effect sensor containing two Hall-effect sensor elements and having a differential output;

said measuring system generating electrical signals proportional to the deflection of said feeler rod from said predetermined position thereof;

a matching circuit operatively connected to said measuring system to receive and standardize said electrical signals and having an input side and an output side; and

said matching circuit having said input side connected with said differential output of said Hall-effect sensor and containing a differential amplifier circuit which is mounted at said housing and which receives the sum of the absolute values of the output voltages generated by said two Hall-effect sensor elements and delivers at said output side a corrected signal.

2. The gear measuring feeler as defined in claim 1, wherein:

said two Hall-effect sensor elements are spatially arranged in opposing relationship to each other with respect to said static magnetic field.

3. The gear measuring feeler as defined in claim 2, wherein:

said two Hall-effect sensor elements constitute two separate, mechanically fixedly interconnected elements.

4. The gear measuring feeler as defined in claim 2, wherein:

each one of said two Hall-effect sensor elements comprises a predetermined side thereof; and

said two Hall-effect sensor elements possessing identical predetermined sides and said two Hall-effect sensor elements being secured to each other at said identical predetermined sides thereof.

5. The gear measuring feeler as defined in claim 1, wherein:

said matching circuit contains an inverter circuit interconnecting one of said Hall-effect sensor elements and said differential amplifier circuit.

6. A gear measuring feeler comprising:

a housing;

a feeler rod pivotably mounted in said housing and deflectable from a predetermined position;

said feeler rod having a first end and a second end;

a feeler probe provided at said first end of said feeler rod;

a measuring system comprising two members which are movable relative to each other;

one of said two members being supported at said second end of said feeler rod;

said two members comprising means for generating a static magnetic field and a Hall-effect sensor;

said Hall-effect sensor containing two Hall-effect sensor elements and having a differential output for delivering a differential output signal;

said measuring system generating electrical signals proportional to the deflection of said feeler rod from said predetermined position thereof;

a matching circuit operatively connected to said measuring system to receive and standardize said electrical signals and having an input side and an output side;

said matching circuit being devoid of a reference voltage source; and

said matching circuit having said input side connected with said differential output of said Hall-effect sensor and containing a differential amplifier circuit which is mounted at said housing and which received the sum of the absolute values of the output voltages generated by said two Hall-effect sensor elements and delivers at said output side an output signal substantially corresponding to said differential output signal of the Hall-effect sensor.