GB190809741A - Improvements in Sound Producing Devices. - Google Patents

Abstract

9741. Northey, J. P. May 5. Sirens.-In a siren or like sound-producing device, two resonators are combined to obtain synchronous vibrations by arranging them back to back with a single instrument or two separate instruments supplied from one source. The resonators may be of the reciprocating type having fixed and moving parts with similar orifices as described in Specification No. 25,268, A.D. 1905, or it may be of the rotating type. In the arrangement shown in Fig. 1, the sound-producing air or steam enters at a and passes through a slotted cylinder b, and through a double slotted piston c, divided by a partition d, into the resonators e. The pistons are reciprocated by steam or air entering at g, passing through a semicircular inlet passage h, and an annular port 1, thus moving the piston head i away from the cylinder head j, and allowing the fluid to pass through annular ports 2, 3, holes 4, and an annular port 5, to the other side of the piston head, so that the piston head is driven in the opposite direction, the inlet port 1 being closed. The position of the ports 5, 1 causes cushioning on each side of the piston head. The fluid exhausts through the port 5, holes 4, port 3, annular space 7, annular port 8, holes 9, semicircular exhaust passage h<1>, chambers 10, 11, and thence to slots n in an extension n' of the cylinder and through corresponding slots o in the piston, thus being utilized to reinforce the sound-producing air. The chamber 11 may be closed by a partition, this portion of the piston head being opened to the air. The piston c has a prolongation c<2> to guide it, and to prevent escape of the driving-fluid. Fig. 2 shows a modified form with a fluid entrance a', and a slotted cylinder b<1>, in which is a second slotted cylinder c<1> rotated on a spindle f by the action of the fluid on the slots. The cylinder c' is divided into two parts by a partition d'.