Nohmi Bosai Ltd.

Nohmi Bosai Kabushiki Kaisha

Yasuo Ariga

Yoshinori Igarashi

Ichirou Kobayashi

Kazuyuki Koganemaru

Toru Sasaki

Makoto Yasukawa

Eiji Hirooka

Ichiro Kobayashi

Kentaro Higashi

Satoru Horiuchi

A photoelectric type fire detector has: a detector body; a printed circuit board disposed on the upper side of the detector body; conductive connecting members provided on the lower side of the detector body; terminal screws for simultaneously fixing the printed circuit board and the conductive connecting members to the detector body; an optic base directly placed on the upper side of the printed circuit board and having a labyrinth formed on the upper side thereof; hooks for fixing the optic base to the upper side of the printed circuit board; a light-emitting element and a light-receiving element arranged in a pair for detecting smoke; a bug screen provided on the outer periphery of the labyrinth of the optic base; an optic base cover covering the upper side of the optic base; and a protective cover covering the printed circuit board, the optic base, the bug screen and the optic base cover. The protective cover has a plurality of smoke inlet windows and is provided with hooks on the lower end thereof, the hooks engaging the detector body to fix the protective cover to the upper side of the detector body. The invention is also applicable to a heat-photoelectric type fire detector in which a heat sensing element connected to the printed circuit board is combined with the photoelectric fire detecting function. The heat sensing element is securely fixed by a protective cover of the device.

Fire detector having optic base clamping optic elements to a circuit

A fire detector includes both a detector unit and a detector base including a base block to which the detector unit is mounted. The detector unit has an outermost peripheral wall, an engaging portion located inwardly of the outermost peripheral wall, and connecting members of a bayonet coupling. The detector base includes coupling members of a bayonet coupling engaged with the coupling members of the detector unit. The bayonet coupling is locked in place by a locking spring of the base block of the detector base, which locking spring engages the engaging portion of the detector unit. A pair of spaced apart connecting terminals for connection with a power and signal line are fixed on the base block. These terminals have small holes, respectively. A jumper spring having a main portion and bent ends is connected to the terminals by inserting the bent portions of the spring into the small holes, to thereby produce a short-circuit which allows the detector base to be inspected prior to the mounting of a detector unit to the base block. The jumper spring may be readily pulled from the terminals even once the base block has been mounted to the ceiling.

Fire detector having bayonet coupling and locking mechanism for base and

A fire detector includes both a detector unit and a detector base including a base block (1) to which the detector unit (4) is mounted. The detector unit has an outermost peripheral wall (4a), an engaging portion (5) located inwardly of the outermost peripheral wall, and connecting members (17,18,19) of a bayonet coupling. The detector base includes coupling members (7,8,9) of a bayonet coupling engaged with the coupling members of the detector unit. The bayonet coupling is locked in place by a locking spring (3) of the base block of the detector base, which locking spring engages the engaging portion (5) of the detector unit. The engaging portion of the detector unit may define a recess (5b), in which case the locking spring has a projection (6) which will snap into the recess (5b) in the detector unit during rotation of the detector unit relative to the detector base to secure the bayonet coupling. The entire portion of the locking spring is disposed within the recess (2) in the base block of the detector base such that a tool must be used to release the locking spring thereby preventing an unauthorized disconnection of the detector unit from the detector base.

Detector base

Smoke detector

A light-scattering-type smoke detector is disclosed which comprises a base portion to be secured to a ceiling, a head part forming one of the parts of a detecting portion to be detachably mounted to the base portion through setscrews passed therethrough, and a dark box forming the other of the portions of the detecting part to be detachably connected to the head part by screwing the setscrews thereto, the dark box comprising a body portion and a cover portion put one upon another. The body portion has a printed circuit board integrally secured thereto on its upper surface and the dark box is surrounded by a labyrinth around its outer periphery that is internally provided with a light projection element and a light receiving element. The smoke detector allows the dismounting of the head part from the base portion, and the dark box from the head part so that maintenance and repair of the smoke detector can be carried out quite easily.

Light-scattering-type smoke detector

Growing community of inventors

Tokyo, Japan

Yasuo Ariga