Abstract: A gas mask is provided which includes a facepiece including a front portion of semi-rigid rubber highly resistant to chemical agents and a sealing skirting of soft rubber having a high mechanical resistance, co-vulcanized with the front portion of the facepiece. A nozzle, connected to a half mask situated inside the facepiece, is tightly fastened to the front portion of the facepiece. An inflow opening and an outflow opening are provided which are substantially coaxial and are located in the lower portion of the nozzle. The inflow opening places the interior of the facepiece into communication with the external atmosphere and the outflow opening places the interior of the half mask into communication with the external atmosphere through an inflow chamber and an outflow chamber which are separated by a partition. The inflow chamber communicates bilaterally with a space located between the half mask and the facepiece.

Abstract: A device is provided for preventing the inflow of air into a gas mask during the substitution of its filter in the presence of a contaminated atmosphere. The device includes a small plate having a central stem which passes through the support for a check valve admitting air to the respiratory tract of the user and a spring which pushes the small plate against the diaphragm of the check valve when the filter is removed from the mask to prevent inflow of air into the mask.

Abstract: A commutator feeding device for a demand valve, comprising a transducer adapted for controlling the movement of a shutter element for feeding predetermined quantities of air into a chamber of said demand valve in response to a pressure variation taking place inside said chamber, said transducer being activated following the shifting of a deformable membrane. The device comprises a spring, disposed inside a small piston, adapted for resting on said membrane, said small piston being provided with radial stakes or spokes, each one of which is adapted to rest on the active surface of a corresponding helicoidal profile cam, with manually operable actuating means being predisposed for controlling the rotation of said small piston around its own axis, and hence the axial shifting of the small piston itself in the spring-compressing sense.

Abstract: An elastomeric or plastomeric power transmission belt is reinforced with longitudinally extending wires or threads which are flexible and substantially inextensible. Longitudinally uniformly spaced rigid members which are embedded cross-wise in the belt with one surface adjacent to the longitudinally extending reinforcing members support the wires or threads during vulcanization or curing of the elastomer or plastomer and resist transversal deformation of the belt during use.

Abstract: An electrical device for signaling a change in physical conditions within a vehicle pneumatic tire mounted on a rim has a sensing element containing at least two electrical contacts which are closed or open to the flow of an electrical current depending upon the physical conditions in the tire, a pair of electrodes connected to the contacts and passing through the wall of the rim, an electrical signaling circuit disposed outside the rim, connected with the electrodes and controlled by the position of the two contacts, the electrical circuit being enclosed in a mass of cross-linked synthetic resin to protect it from excessive wear due to dust, rain and mud.