Antitheft device preventing injection of foam in siren housing - has movable wall part(s) operating alarm switch

摘要

The anti-foam protecting arrangement described is equipped with a housing (1), with at least one movable wall-component. Movement of this component (2) activates a reed switch (8) releasing the alarm. The housing is made in the form of a box or case closed on all sides, with a wiper arrangement (2) fitted on one side and designed to sweep across it. For stability against pressure it is pref. of metal or hard plastics material. USE/ADVANTAGE - Any attempt to project foam into housing can be reliably detected. Suitable for security and defence installations.