To warn nearby people of danger, for example when a train is approaching a railway crossing, or when an abnormal situation arises in a factory or the like, in general a warning sound is produced using a siren, a bell or the like. More recently, a speaker or a piezoelectric buzzer has been used for producing the warning sound.
With such a conventional warning apparatus wherein a dangerous situation is notified by producing a warning sound, the warning apparatus is only driven to produce the warning sound when the dangerous situation arises, while at normal safe times, it is not driven so that the warning sound is not generated.
However, in particular at factories and the like, dangerous situations wherein the warning apparatus is operated seldom arise. Hence, it cannot be known if there is a fault in the warning apparatus. It is therefore uncertain if the warning apparatus can normally produce a warning sound when a dangerous situation actually arises, so that there is extreme danger to nearby personnel in the case of a fault such that the warning sound is not sounded.
The present invention takes into consideration the above situation with the object of providing a highly reliable warning apparatus which can verify if a warning sound can be produced, even at normal safe times where it is not necessary to warn personnel.
USPTO Backgrounds
USPTO Backgrounds