Pneumatic sound source

Claim 1

A PNEUMATIC SOUND SOURCE COMPRISING: HOUSING MEANS COMPRISING A SUBSTANTIALLY LONGITUDINAL STRUCTURE OPEN AT ONE OF ITS LONGITUDINAL-AXIS ENDS AND HAVING AN EXCISED CENTRAL CHAMBER ENCLOSED BY A WALL AND A CEILING OPPOSITE THE OPEN END, SAID STRUCTURE BEING FORMED WITH A SECOND CHAMBER ENCLOSED SAID CEILING, SAID TWO CHAMBERS COUPLING WITH EACH OTHER, AND THE TRANSVERSE CROSS-SECTIONAL AREA OF SAID SECOND CHAMBER BEING LESS THAN THAT OF SAID CENTRAL CHAMBER, SAID STRUCTURE ALSO BEING FORMED WITH AN UPPER, A LOWER AND A MIDDLE PORT IN SAID WALL; PISTON MEANS LOCATED WITHIN SAID CENTRAL CHAMBER AND COMPRISING A CENTRAL SHANK BEARING THREE ENCIRCLING FLANGES, AN UPPER FLANGE AT ONE END, A LOWER FLANGE AT THE OTHER END, AND A MIDDLE FLANGE BETWEEN THE OTHER TWO, THE SIDES OF SAID FLANGES BEARING AGAINST SAID HOUSING MEANS WALL TO FORM A LOWER CHAMBER AND A MIDDLE CHAMBER WHICH IS INTERMEDIATE SAID LOWER CHAMBER AND SAIDS SECOND CHAMBER, THE SURFACE OF SAID UPPER FLANGE SEALING OFF SAID SECOND CHAMBER IN A FLUID-TIGHT MANNER WHEN SAID SURFACE IS PRESSED AGAINST THE INTERNAL SURFACE OF SAID CEILING, SAID CENTRAL SHANK BEING FORMED WITH A CONDUIT THEREIN COUPLING SAID LOWER CHAMBER WITH SAID SECOND CHAMBER, SAID UPPER PORT BEING LOCATED CLOSE TO THE INTERNAL SURFACE OF SAID CEILING, SAID MIDDLE PORT COUPLING WITH SAID MIDDLE CHAMBER AND SAID LOWER PORT COUPLING WITH SAID LOWER CHAMBER; AND SEALING MEANS FOR SEALING SAID CHAMBERS AGAINST THE PASSAGE OF FLUID THEREBETWEEN, SAID SEALING MEANS PERMITTING SAID PISTON MEANS TO SLIDE WITHIN SAID HOUSING MEANS, SO THAT SAID LOWER CHAMBER IS COMPLETELY SEALED FROM THE OUTSIDE ENVIRONMENT WHEN SAID UPPER FLANGE IS PRESSED AGAINST SAID CEILING AND IS EXPOSED TO THE OUTSIDE ENVIRONMENT WHEN SAID PISTON MEANS IS MOVED DOWNWARDS.