General Signal Corporation

Charles Berns

Jacob Neuhof

Vaclav Oldrich Podany

A buzzer structure, of the type comprising a housing having a coil unit therein and an armature mounted for vibratory movement adjacent the coil unit, includes in one embodiment an integral portion of the housing which is bent inwardly into engagement with the coil unit to fix the spacing between the coil unit and housing, thereby to determine the dimensions of the gap between the coil unit and armature. In a further embodiment, the coil unit is mounted directly to a deformable, integral part of the housing which is bent inwardly to fix the spacing between the coil unit and an adjacent diaphragm. The spacing and gap dimensions are adjusted, after the buzzer elements are assembled, by energizing the coil unit, applying a force to a portion of the housing to progressively deform it to displace the coil unit in engagement therewith, and monitoring the magnitude of current flow through the coil unit while simultaneously monitoring the sound output of the buzzer to determine when a proper operating point has been reached, at which time the progressive deformation of the housing and displacement of the coil unit are immediately terminated.

Buzzer construction and method of adjusting the same

Smoke detection apparatus including a pair of photoelectric cells which receive illumination selectively from a very low level light source. One of the cells is termed the 'direct' cell because it is in the direct path or on the axis of a narrow conical beam of light emanating from the source, the other cell being termed the 'reflected' cell because it receives a significant part of its light input upon reflection of light from smoke particles or the like as such particles are drawn into the path of the light beam. Under predetermined smoke conditions, i.e., when there is smoke obscuration of the light of 2% per foot (.01 optical density), an alarm signal is triggered. The very low level light source is a light-emitting diode which sensitively monitors the smoke obscuration; only a slight change in the illumination to the pair of photocells, connected in a sensing circuit, is required to produce the triggering signal. Accordingly, the smoke detection apparatus is highly sensitive to the presence of either so called 'white' smoke or 'black', i.e. non-reflective smoke, and either or both will trigger the alarm signal.

Smoke detector

An electronic circuit including a transistor which is biased to conduction is provided to initiate actuation of an electromagnetic transducer. The transducer has first and second coils one of which actuates the sounder. A potential is induced in the other coil and this induced potential is used to cut off the transistor. The next cycle of operation is initiated when the induced potential falls below a predetermined value in response to the reduction of the magnetic flux which, in turn, was the result of the transistor having been cut off.

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New Milford, CT, United States of America

Charles Berns