GB1126944A - Valve for sound attenuating device - Google Patents

Abstract

1,126,944. Helmets; ear protectors. L. P. FRIEDER. 13 May, 1966 [2 June, 1965], No. 21474/66. Heading A3V. [Also in Divisions A5 and H4] A sound attenuating device comprises an ear cup adapted to receive an ear of a wearer and having an aperture spaced from the rim of the cup, a valve movable between a closed position withinthe aperture and an open position completely outside the aperture, and means connecting the valve to the ear cup in all positions of the valve. As illustrated in Fig. 2, an ear cup 14 comprises a wall 30 from the rim of which extends an annular flange 33 to which is fixed a ring 34 of resilient material, for example sponge rubber, having a cover 35 of pliant material, for example leather; extending radially about the wall of the cup are annular flanges 36 and 37 which retain an endless cord 38 about which are looped straps, such as 15, by means of which the cup may be secured by screws, such as 17, to a helmet. Disposed within the cup is resilient sound absorbing material in the form of a body 40 and a layer 42 which are shaped to define a pocket 41 for receiving telephonic equipment, for example a receiver, and a passageway 43 for providing communication from the outside of the cup via an aperture 49 formed in the wall of the cup to a space 32 defined within the cup by the sound absorbing material. The aperture is formed in a boss 48 which is integral with the wall of the cup and which provides a valve seat 47 formed by the cylindrical surface 49a defining the aperture and by planar annular boss surfaces 49b and 49c which surround the aperture. As illustrated in Fig. 9, the valve includes a valve plug 46 formed of a resilient non- porous material, for example a plastics material, and comprising a drum 46a to one end of which is joined a flange 46b, the drum being adapted to be received in the aperture in the wall of the cup and the flange being adapted to engage the outer surface of the cup in the closed position of the valve. The flange is formed with the first tab 50 forming a flexible hinge, which connects the valve to the ear cup, and with a diametrically opposed second tab 51 forming graspable means for moving the valve between the open and closed positions; to facilitate grasping, the rib 51a may project transversely from the surface of the second tab. A screen, for example a fine wire mesh, may extend across the inner end of the aperture to prevent ingress of foreign objects into the cup when the valve is open. The drum defines a closed chamber filled with a gas, a liquid or a particulate solid material, preferably a fluent sound absorbing material, for example lead oxide. Two constructions of the drum and associated flange are fully described and illustrated in the Specification.