Optical smoke detector

Claim 2

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light excluding and smoke transmissive entry to the dark chamber, an optical block assembly forming means to position an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, the block comprising means to shield the photocell from direct light from the lamp, guide means on the base slidingly receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define a dark chamber, and a light excluding cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and operational assembly of the smoke detector, the cover and sidewall having integral telescopingly interengaging portions positively positioning the cover on the base.

Claim 3

A detector according to claim 1 wherein a lamp and photocell respectively are mounted in said support means, the lamp emitting a light beam into the dark chamber and the cell sensing light scattered by smoke from the beam.

Claim 4

A detector according to claim 1 wherein a lamp and photocell are mounted in said respective support means of the block, and the block comprising an open ended socket adjacent to the lamp and a light pipe held in the socket, and an aperture in the cover aligned with the socket through which the light pipe extends to the exterior of the cover to indicate operation of the lamp.

Claim 5

A detector according to claim 1 wherein the cover comprises two mating parts, an inner cover fitting the optical block and having an aperture opening into the dark chamber, and an outer cover fitting over the aperture and including means passing smoke and excluding light from the aperture.

Claim 6

A detector according to claim 4 wherein the base side wall comprises a porous material excluding light and passing smoke and cooperating with the cover aperture to circulate amoke through the dark chamber in various installed orientations of the detector.

Claim 7

A detector according to claim 2 wherein the optical block assembly comprises a planar circuit board mounting the electronic components of an alarm circuit, the board having parallel edges at opposite ends, and the guide means on the base comprising grooved means receiving the parallel edges.

Claim 8

A detector according to claim 6 wherein the cover engages the board to secure it in place.

Claim 9

A detector according to claim 6 wherein the optical block and circuit board are physically joined, and a lamp and photocell are mounted in the support means of the base and are electrically, operationally connected to the alarm circuit and responsive to sensing of smoke by the cell to indicate a predetermined smoke density.

Claim 10

A detector according to claim 1 wherein said cover comprises a keyhole shaped aperture and the optical block assembly includes a pair of spaced electrical terminals, the detector further comprising a face plate overlying the cover, the face plate having a key snapfitting in the keyhole and a spring detent snapfitting between the terminals electrically to connect the terminals and secure the face plate to the detector.

Claim 11

A detector according to claim 9 wherein the detector iNcludes an electronic alarm circuit operatively connected through said terminals and detent.

Claim 12

A smoke detector according to claim 1 wherein the base sidewalls and cover form smoke passages communicating with the dark chamber on at least three substantially divergent solid angles.

Claim 13

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light excluding and smoke transmissive entry to the dark chamber, an optical block assembly forming means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, the optical block comprising two substantially symmetrical mating halves with semi-annular recesses receiving the photocell and forming the passages and spaced openings, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and assembly of the smoke detector.

Claim 14

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light excluding and smoke transmissive entry to the dark chamber, an optical block assembly forming means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, the optical block comprising two substantially symmetrical mating halves with semi-annular recesses receiving the photocell and forming the passages and spaced openings, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and assembly of the smoke detector.

Claim 15

A detector according to claim 12 wherein the optical block includes a second photocell with a photosensitive surface the block forming a third passage therefrom to the lamp passage, and the third passage mounting at least one diffuser disk and at least one pin hole apertured disk aligned with the second cell to diffuse a controlled amount of light over its photosensitive surface.

Claim 16

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light exclusing and smoke transmissive entry to the dark chamber, an optical block assembly forming means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and operational assembly of the smoke detector, wherein said one side of the optical block comprises a track slidingly receiving a flexible strip over the cell opening thereby to mask the cell, the base side wall having an outlet therethrough adjacent to one end of the track, and a flexible strip in said track including means extending through said outlet, whereby the detector may be assembled while maintaining the cell in the dark, whereafter the strip may be withdrawn from the track unmasking the cell for operational sensing of light in the dark chamber.

Claim 17

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light exclusing and smoke transmissive entry to the dark chamber, an optical block assembly forming means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and operational assembly of the smoke detector, wherein said one side of the optical block comprises a track slidingly receiving a flexible strip over the cell opening thereby to mask the cell, the base side wall having an outlet therethrough adjacent to one end of the track, and a flexible strip in said track including means extending through said outlet, whereby the detector may be assembled while maintaining the cell in the dark, whereafter the strip may be withdrawn from the track unmasking the cell for operational sensing of light in the dark chamber.

Claim 18

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light excluding and smoke transmissive entry to the dark chamber, an optical block assembly forning means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and operatonal assembly of the smoke detector, wherein the optical block assembly comprises a planar circuit board mounting the electronic components of an alarm circuit, a portion of the board forming with the base side wall a passage to the dark chamber, the circuit including an ohmic component heating air in the passage to promote smoke circulation.

Claim 19

An optical smoke detector structure comprising: a base forming a bottom wall and a side wall partially surrounding a dark chamber and having a light excluding and smoke transmissive entry to the dark chamber, an optical block assembly forning means to support an exciter lamp and a photocell and passages respectively leading from the lamp and cell to spaced openings at one side of the block, means on the base receiving the optical block assembly and positioning said side of the block opposite the base side wall thereby to define the dark chamber, and a cover for the dark chamber fitting over the block and side wall to complete enclosure of the dark chamber and operatonal assembly of the smoke detector, wherein the optical block assembly comprises a planar circuit board mounting the electronic components of an alarm circuit, a portion of the board forming with the base side wall a passage to the dark chamber, the circuit including an ohmic component heating air in the passage to promote smoke circulation.

Claim 20

A detector according to claim 15 wherein said circuit board portion and the side wall converge in a funnel toward the dark chamber.

Claim 21

A detector according to claim 16 wherein the lamp and cell passages are aligned with an intersection zone and the funnel converges toward the zone.