Surveying instrument incorporating a magnetic incremental rotary encoder
AssigneesPENTAX Corporation, Pentax Precision Co., Ltd.
InventorsMasami Shirai, Katsuhiko Kenjo
Life of this patent
Estimating the term…
Abstract
A surveying instrument which incorporates a magnetic incremental rotary encoder includes a rotary magnetic drum provided on an outer peripheral surface thereof with a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions, a pair of magnetic sensors located on opposite sides of said rotary magnetic drum so that each of said pair of magnetic sensors faces said multi-pole magnetized layer, and at least one magnet, positioned in the vicinity of at least one of said pair of magnetic sensors, for reducing an error in detection of said magnetic incremental rotary encoder.
Claims12
A surveying instrument which incorporates a magnetic incremental rotary encoder, comprising:
- a rotary magnetic drum having, on an outer peripheral surface, a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions;
- at least one magnetic sensor located so as to face said multi-pole magnetized layer;
- and
- at least one magnet, positioned in the vicinity of said at least one magnetic sensor, said at least one magnet being configured to reduce an error in detection of said magnetic incremental rotary encoder;
- wherein said at least one magnet is configured and positioned so that primary lines of magnetic force develop substantially parallel to a sensor surface of a corresponding magnetic sensor, and substantially orthogonal to lines of a magnetic field of said multi-pole magnetized layer.
A surveying instrument comprising:
- a leveling board;
- a pedestal coupled to said leveling board to be rotatable about a vertical axis relative to said leveling board;
- a collimating telescope coupled to said pedestal to be rotatable about a horizontal axis relative to said pedestal;
- a horizontal-angle measuring device for measuring an angle of rotation of said pedestal relative to said leveling board;
- and
- a vertical-angle measuring device for measuring an angle of rotation of said collimating telescope relative to said pedestal,
- wherein at least one of said horizontal-angle measuring device and said vertical-angle measuring device comprises a magnetic incremental rotary encoder,
- wherein said magnetic incremental rotary encoder comprises a rotary magnetic drum having, on an outer peripheral surface, a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions;
- at least one magnetic sensor;
- and at least one magnet, positioned in the vicinity of said at least one magnetic sensor, said at least one magnet being configured to reduce an error in detection of said magnetic incremental rotary encoder;
- wherein said at least one magnetic sensor comprises a plurality of magnetoresistor elements and is positioned so as to face said multi-pole magnetized layer;
- and
- wherein said at least one magnet is configured and positioned so that primary lines of magnetic force develop substantially parallel to a sensor surface of a corresponding magnetic sensor, and substantially orthogonal to lines of a magnetic field of said multi-pole magnetized layer.
Dependencies are inferred from the claim text.