Magnetic switch capable of performing normal detection for a long period of time

• US 6,784,774 B1
• Filed: 02/18/2004
• Issued: 08/31/2004
• Est. Priority Date: 02/24/2003
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Okumura, Hirofumi
• Primary Examiner(s): Barrera, Ramon M.
• Application Number:
  US10/782,089
• Publication Number:
  US 20040164826A1
• Time in Patent Office: 195 Days
• Field of Search: 335/151-154, 335/205-207, 280/735, 324/207.11, 324/207.2, 324/207.24, 324/207.25, 324/207.26
• US Class Current: 335/205
• CPC Class Codes: B60N 2/0244 with logic circuits
• CPC Class Codes: B60N 2/0268 using sensors or detectors for adapting the seat or seat part, e.g. to the position of an occupant
• CPC Class Codes: B60N 2/0705 omega-shaped
• CPC Class Codes: B60N 2/0715 C or U-shaped
• CPC Class Codes: B60N 2002/684 the back rest being mounted or joined with an easy attachment system to the seat
• CPC Class Codes: B60N 2210/14 Inductive; Magnetic field
• CPC Class Codes: B60R 21/01554 Seat position sensors
• CPC Class Codes: B62H 1/02 Articulated stands, e.g. in the shape of hinged arms B62H1/10 takes precedence
• CPC Class Codes: H03K 17/9502 Measures for increasing reliability
• CPC Class Codes: H03K 17/9517 using galvanomagnetic devices

Abstract

A magnetic switch hardly affected by an external magnetic field even if a cheap magnet is used and capable of performing magnetic detection for a long period of time is provided. A first magnetic path L1 and a second magnetic path L2 in which a stationary rail 13 and a movable rail 14 lead magnetic fluxes are formed in a non-shielding state where magnetism shielding 18 is not interposed in a gap G between a magnet M and a Hall element H to secure the number of magnetic fluxes that pass through the Hall element H. Therefore, it is not necessary to use a costly rare earth magnet having a large number of generated magnetic fluxes. In n shielding state where the magnetism shielding 18 is interposed in the gap G, the first magnetic path L1 is shielded. As a result, the number of magnetic fluxes that pass through the Hall element H is almost zero. Since the magnet M and the Hall element H are covered with the stationary rail 13 and the movable rail 14, the magnetic switch is hardly affected by the external magnetic field.

Claims

1. A magnetic switch, comprising:

magnetism detecting means having a Hall element that faces a magnet through a gap; and

magnetism shielding means provided so as to freely enter and exit the gap,

wherein the external surface of the magnetism detecting means is covered with a case made of a magnetic material.

2. The magnetic switch according to claim 1,

wherein the magnetism shielding means is made of a magnetic material.

3. The magnetic switch according to claim 1, further comprising:

a stationary rail fixed to a floor;

a movable rail guided by the stationary rail and provided so as to be freely movable; and

a seat fixed to the movable rail and capable of being moved back and forth along with the movable rail,

wherein the magnetism detecting means is provided in either the stationary rail or the movable rail, and the magnetism shielding means is provided in the other.

4. The magnetic switch according to claim 1, further comprising:

a vehicle body; and

a stand for supporting the vehicle body,

wherein the magnetism detecting means is provided in either the vehicle body or the stand, or the magnetism shielding means is provided in the other.

5. The magnetic switch according to claim 1,

wherein the magnet and the Hall element are integrally received in the case.