Abstract: A triangular, sharp projection is formed in the surface of a key handle, the projection being directed into the interior of a key ring opening formed therein. This key ring projection includes edge recesses formed proximate the base thereof thereby providing a shape forcing the segments of a collapsed helical key ring apart, the recesses then maintaining the ring segments separated for insertion or removal of additional keys. In an alternative implementation the similar key ring separation projection may be formed on articles other than keys that can thus be carried on the key ring for convenience in key removal.

Abstract: A two-piece outer casing encloses a volume with a central divider plate which extends the length of the casing. The two portions of the casing are bolted or otherwise clamped about the divider plate. Each half of the outer casing has angled inner ribs or diverters. The diverters in one casing extend at an opposite angle to the longitudinal axis of the central plate as do the diverters of the other outer casing. The inner edges of the diverter seal against the surface of the central plate. The transverse dimension of the central plate is less than the transverse dimension of the diverters and the outer casing such that an exchange aperture is defined between the central plate and the inner surface of the outer casing between adjacent pairs of diverters. The casing has an exhaust input port and an exhaust outlet port at opposite ends and opposite sides.

Abstract: A sound damping apparatus has a resilient wall that defines a first volume and rigid wall defining a second or third volume. One rigid wall may be a part of the device muffled. A gas entry communicates with the volume defined by the resilient wall. The resilient wall and the rigid walls are in contact such that gas pressure separates the walls and the wall to intermittently define gas passages between volumes. Fluid within the wall surrounding the resilient wall dampens resilient wall vibration.

Abstract: A sound damping apparatus has a resilient wall that defines a first volume and rigid walls defining a second or third volume. A gas entry communicates with the volume defined by the resilient wall. The resilient wall and the rigid walls are in contact such that gas pressure separates the walls and the wall to intermittently define a gas exit between volumes within the wall.