|국가/구분||United States(US) Patent 등록|
|발명자 / 주소|
|출원인 / 주소|
|인용정보||피인용 횟수 : 10 인용 특허 : 0|
A variable intensity whistle is formed by a cylindrical chamber having apertures in opposite ends. The centers of the apertures are off set with respect to the cylinder axis and the chamber is formed in two parts which are rotatable relative to each other to either align the apertures and displace them by predetermined amounts.
A variable intensity whistle comprising wall means forming a chamber having a fixed axis, said wall means comprising spaced opposing first and second wall members, said first wall member having an aperture therein the axis of which is displaced relative to said axis of said chamber and said second wall member having an opening therein the axis of which is also displaced relative to said axis of said chamber, said first and second wall members being relatively movable with respect to each other to selectively provide axial alignment or displacement betwee...