A receiving unit including an operational amplifier having a fixed gain receives an electromagnetic signal, from which a voltage divider with a variable resistance generates an input voltage for the amplifier. The amplifier's output voltage is compared with a reference voltage. The variable input resistance is adjusted to vary the amplifier's input voltage, until the amplifier's output voltage lies within a defined range around the reference voltage. This adjusted resistance value is compared wi...

A method detects relaying of a contactless data communication by a radio amplifier for intercepting and manipulating the communication to achieve an unauthorized authentication. The method involves transmitting an electromagnetic field successively from at least two spatially separated antennas of a transmitting unit, receiving the transmitted fields in a receiving unit, determining field strength vectors of the received fields allocated to each antenna, and comparing actual values of the vector...

A method of manufacturing concentric machine elements from flat steel strips by permanently bending a flat steel strip of limited length along its longitudinal axis, and burring the concave surface of the strip, while supported, through the application of a force on the convex surface of the strip, so that a concentrically shaped casing is formed.

A headphone earpiece for wearing on a person's ear, comprises an annular pad adapted to engage around the ear and a sound transducer having a transducer diaphragm supported within said pad so as to define a coupling space between the transducer diaphragm and the person's ear. The support means includes a rigid plate between the diaphragm and the pad which has frictional resistances distributed thereover and which may advantageously comprise the material of the plate itself or a plurality of open...

A dispenser for a retractable safety belt, to be used by the driver of a vehicle, comprises a holder in which a roller loaded by a retraction spring is journaled. The belt, anchored to the roller and partly wound around it, coacts with an insert in the form of a resilient ribbon which is coiled with the belt about the roller during at least an initial phase of a pull-out stroke and about a collateral axis alongside the belt during at least a final phase of that stroke of exert upon the belt a su...

The connecting duct which directs the flock-laden air stream into the chute is provided with a restriction as well as with a ring duct for directing air impulses into the duct via openings on opposite sides of the duct. The restriction causes the air stream to accelerate and, since the air flow is closer to one opening, rather than the other, a reduced pressure is created on that side. This, in turn, causes a pulse of air to travel from one end of the ring duct to the other. The air pulse contin...

A commutator structure for use on the rotor of a dynamo-electric machine includes a cylindric assembly of commutator segments held together by shrink rings. The commutator segment assembly is mounted on a cylindric support part such as a bush or the rotor shaft itself, there being established between the commutator segment assembly and support part an annulus with an elastic layer. Preferably the elastic layer is constituted by absorbant material such as fiber glass impregnated with a thermo-set...

A method of manufacturing concentric machine elements from flat steel strips by permanently bending a flat steel strip of limited length along its longitudinal axis, and burring the concave surface of the strip, while supported, through the application of a force on the convex surface of the strip, so that a concentrically shaped casing is formed.

A device for measuring rotational angles of a rotating shaft of a machine, and comprising transducers signals of which being released by one or several reference angle signs or a machine characteristic phenomenon respectively, and being input to a processing unit. The processing unit comprises a frequency multiplier circuit and a counter the frequency multiplier circuit multiplying the signal of one or several reference angle signs, with the counter counting the multiplied signals and being rese...

A continuously variable, conical disk transmission including a torque-transmitting member in the form of a plate-link chain or a thrust link band. The chain includes plate links that are interconnected by pairs of rocker members that extend transversely relative to the chain movement direction. The thrust link band includes a number of thrust links that are in face-to-back contact and that extend transversely relative to the band movement direction. Each of the rocker members and the thrust link...