Magnetic material detection device and mobile object detection system

• US 20070188161A1
• Filed: 03/19/2004
• Published: 08/16/2007
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Asa Electronics Industry Co., Ltd. (VOXX International Corporation)
• Original Assignee: Asa Electronics Industry Co., Ltd. (VOXX International Corporation)
• Inventors: Asa, Yukihiro
• Granted Patent: US 7,791,336 B2
• Time in Patent Office: Days
• US Class Current: 324/207.110
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

The purpose is to achieve size reduction, weight reduction and thickness reduction of a magnetic material detecting device (1). The device comprises a liearly displaceable magnet (12) and a Hall IC (14) for detecting the displacement of the magnet (12). When an iron piece (28) is positioned within a predetermined distance from the main body of the magnetic material detecting device (1), the iron piece (28) is strongly magnetized to attract the magnet (12) so that the latter is displaced toward the iron piece (28). Therefore, when the displacement of a magnet (14) is detected by the Hall IC (14), it is possible to detect the fact that the iron piece (28) has been positioned within the predetermined distance from the main body of the magnetic material detecting device (1).

Claims

1. A magnetic material detection device

wherein a magnet displaceable in the direction of magnetic poles and detecting means for detecting displacement of the magnet are set such that the boundary of north and south poles of said magnet crosses the operating point of said detection means after displacement, and

wherein the magnetic material detection device detects that a magnetic material located outside the magnetic material detection device body is located within a predetermined distance from said magnetic material detection device body.

2. A magnetic material detection device according to claim 1 comprising returning means for returning the magnet to the position before displacement, when it is located far from the predetermined distance after the magnetic material is located to the predetermined distance.

3. A magnetic material detection device according to claim 1 comprising an elastic body whose one end is connected to the magnet side and whose other end is connected to the magnetic material detection device body.

4. A magnetic material detection device according to claim 1 wherein a supporting member whose one end is connected to the magnet side and whose other end is connected to second magnet which is different from said magnet, such that the second magnet locates near a path of the magnetic material.

5. A magnetic material detection device according to claim 1 wherein the configuration of the magnet is any one of a cube, a rectangular solid, a cylinder or a pipe.

6. A mobile object detection system comprising the magnetic material detection device according to claim 1 and an mobile object comprising the magnetic material.