Electronic caliper using a reduced offset induced current position transducer

US5901458A · kind A · utility

Assignee

• Mitutoyo Corporation · JP

Inventors

• Nils Ingvar Andermo · Kirkland, US
• Karl G. Masreliez · Stockholm, SE

Key dates

• Filing date: Nov 21, 1997
• Grant date: May 11, 1999
• Expiry date: Nov 21, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B3/205
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An electronic caliper having a reduced offset position transducer that uses two sets of coupling loops on a scale to inductively couple a transmitter winding on a read head on a slide to one or more receiver windings on the read head. The transmitter winding generates a primary magnetic field. The transmitter winding is inductively coupled to first loop portions of first and second sets of coupling loops by a magnetic field. Second loop portions of the first and second sets of coupling loops are interleaved and generate secondary magnetic fields. A receiver winding is formed in a periodic pattern of alternating polarity loops and is inductively coupled to the second loop portions of the first and second sets of coupling loops by the secondary magnetic fields. Depending on the relative position between the read head and the scale, each polarity loop of the receiver winding is inductively coupled to a second loop portion of either the first or second set of coupling loops. The relative positions of the first and second loop portions of the first and second sets of coupling loops are periodic and dependent on the relative position of the coupling loops on the scale.