Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – With electromagnetic field
Reexamination Certificate
1999-02-11
2001-09-25
Oda, Christine (Department: 2862)
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
With electromagnetic field
C324S144000
Reexamination Certificate
active
06294907
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
The present application is based on and claims priority from Japanese Patent Applications Hei 10-99358 filed on Apr. 10, 1998, Hei 10-127683 filed on May 11, 1998, and Hei 10-127684 filed on May 11, 1998, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cross-coil type indicating instrument for use in a vehicle or a general industrial apparatus.
2. Description of the Related Art
As shown in JP-Y2-7-14902, a common cross-coil type indicating instrument has a hollow cylindrical bobbin and a cup-shaped shield casing. The bobbin is composed of upper and lower bobbin members, and the lower portion thereof is covered by the shield casing. Upper end of the upper bobbin member has a center cylinder extending from the upper surface of a cross-coil unit disposed around the bobbin, thereby forming a dead space. The bobbin rotatably supports a pointer shaft at upper and lower bearing portions thereof. The permanent magnet rotor and the pointer are fixed to be driven by the cross-coil unit when it is energized.
In order to make the indicating instrument more compact, it is necessary to reduce the dead space and friction force between the bearing portions and pointer. Friction force necessitates to increase the size of the cross-coil unit and permanent magnet rotor.
SUMMARY OF THE INVENTION
A main object of the invention is to provide a compact cross-coil type indicating instrument.
Another object of the invention is to provide an improved bobbin having bearings of a pointer shaft that reduces the friction between the bearings and the pointer shaft. The friction force is reduced by providing a maximum span of the bearings available to a cross-coil type indicating instrument.
In a cross-coil type indicating instrument according to a main aspect of the invention, an upper center cylinder extends from a bobbin to be flush with the upper surface of a cross coil unit, and a lower center cylinder extends through a magnetic shield casing to a portion in a dead space at the back of the magnetic shield casing.
In the cross-coil type indicating instrument as stated above, the shaft inclines to the horizon at an angle about 20°. Preferably, the lower bearing is located 2 to 8 mm back from the magnetic shield casing.
REFERENCES:
patent: 4758784 (1988-07-01), Baker et al.
patent: 5550465 (1996-08-01), Yamamoto et al.
patent: 5686832 (1997-11-01), Ayres et al.
patent: 3-39169 (1991-04-01), None
patent: 3-40567 (1991-04-01), None
patent: 7-14902 (1995-04-01), None
Koumura Takashi
Miyagawa Isao
Ogawa Naoto
Andersen Henry S.
Denso Corporation
Oda Christine
Pillsbury & Winthrop LLP
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