Dust detector for vacuum cleaner

• US 5,163,202 A
• Filed: 08/14/1991
• Issued: 11/17/1992
• Est. Priority Date: 06/15/1988
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Corporation)
• Inventors: Ishii, Mitsuo, Shimada, Sadahiro, Asada, Shuji, Kawakami, Hiroshi
• Primary Examiner(s): Coe, Philip R.
• Assistant Examiner(s): COOLEY, CHARLES E
• Time in patent office: 461 Days
• Field of Search: 15/319, 15/339, 250/239, 250/573, 250/574, 356/438, 356/439, 356/72, 357/17, 357/72-74
• US Class Current: 15/319
• CPC Class Codes: A47L 9/2815 using optical detectors
• CPC Class Codes: A47L 9/2842 Suction motors or blowers
• CPC Class Codes: A47L 9/2857 User input or output elements for control, e.g. buttons, switches or displays

Abstract

A dust detector in a vacuum cleaner includes a light-emitting element exposed into a dust suction passage for emitting a light beam into the dust passage, and a light-detecting element exposed into the dust suction passage for detecting the light beam emitted from the light-emitting element. A detector unit detects the amount of dust flowing through the dust suction passage based on the intensity of the light beam transmitted from the light-emitting element across the dust suction passage to the light-detecting element. The light-emitting element and the light-detecting element are covered respectively by a pair of light-transmissive covers having respective end faces exposed into the dust suction passage and lying flush with an inner wall surface of the dust suction passage.

Claims

1. A dust detector for a vacuum cleaner, comprising:

a dust suction passage for passing dust therethrough;

a light-emitting element for emitting light into said dust suction passage;

a light-emitting element cover disposed perpendicular to an axis of said dust suction passage for covering and holding in place said light-emitting element, said light-emitting element cover substantially enclosing said light-emitting element and being transmissive to said emitted light;

a light-emitting element cover end face exposed to said dust suction passage, said light-emitting element cover end face being flush with an inner wall surface of said dust suction passage and having a diameter equal to or less than the diameter of said light-emitting element;

a light-detecting element disposed to receive light emitted by said light-emitting element for detecting said light;

a light-detecting element cover disposed perpendicular to said axis of said dust suction passage for covering and holding in place said light-detecting element, said light-detecting element cover substantially enclosing said light-detector and being transmissive to said emitted light;

a light-detecting element cover end face exposed to said dust suction passage, said light-detecting element end face being flush with an inner wall surface of said dust suction passage and having a diameter equal to or less than the diameter of said light-detecting element; and

a detector unit, coupled to said light-detecting element, for determining the amount of said dust passing through said dust suction passage, said detector unit being responsive to the intensity of light detected by said light-detecting element.

2. A dust detector according to claim 1, wherein said diameters of said end faces are such that said emitted light is collimated to a desired level.

3. A dust detector according to claim 1, wherein:

said light-emitting element and said light-detecting element are disposed opposite one another in said dust suction passage; and

said element are in direct optical communication with one another.

4. A dust detector according to any one of claims 1-3, wherein:

said inner wall surface of said dust suction passage includes a taper surface becoming progressively smaller in diameter in a downstream direction with respect to a direction in which the dust passes through the dust suction passage;

said taper surface has a downstream terminal end; and

said light-transmissive covers are disposed adjacent to and downstream of the terminal end of said taper surface.

5. A dust detector according to any one of claims 1-3 further comprising:

light absorbing material disposed proximate to said light-emitting element and said light-detecting element.

6. A dust detector according to claim 5, wherein said light-absorbing material is a black material.

7. A dust detector according to claim 5, wherein said light-absorbing material is infrared absorbent.