Abstract: A novel threaded fastener is provided having an elongated shank portion with a first end and a second end opposed to the first end, and a helical thread in the form of a continuous helical ridge that is arranged on an external surface of the shank portion. The helical thread includes an asymmetrical threaded portion that has a progressively increasing axial displacement of a pressure flank of the helical thread between the first end and the second end of the shank portion, and a progressively decreasing axial displacement of a non-pressure flank of the helical thread between the first end and the second end of the shank portion. When assembled, the novel threaded fastener has a clamping force distribution that is evenly distributed on the helical threads along its axis in the direction of force transmission reducing the risk of self-loosening and increasing fatigue resistance.

Abstract: A fastener and a system, apparatus, and method for monitoring a fastener are described. The fastener includes a head portion, a shank portion, a transponder, and a compression spring, wherein the head portion includes a mounting portion, and wherein the transponder is disposed in the mounting portion of the head portion. The transponder is arranged to monitor the shank portion, and includes an ultrasonic sensor and a signal processing circuit. The ultrasonic sensor is affixed to a transducer hosting surface, and is urged against the transducer hosting surface by placement of the printed circuit board in the head portion with the compression spring intervening therebetween. The ultrasonic sensor communicates with the signal processing circuit via the compression spring. The signal processing circuit captures a signal from the ultrasonic sensor and transforms the signal into a parameter corresponding to a tensile force being exerted by the fastener.

Abstract: Screw elements are provided which include a shank having a thread and a head connected to the shank, the head having a tool engagement portion which comprises six corner domes arranged evenly distributed in the peripheral direction of the head and comprising respective flanks, by which the head can be brought into positive cooperation with a hexagon socket of a tool for tightening of the screw element, wherein respective recesses are arranged peripherally between the corner domes, and wherein the flanks of the corner domes are respectively provided at least partially with a radius.

Abstract: Screw elements are provided which include a shank having a thread and a head connected to the shank, the head having a tool engagement portion which comprises six corner domes arranged evenly distributed in the peripheral direction of the head and comprising respective flanks, by which the head can be brought into positive cooperation with a hexagon socket of a tool for tightening of the screw element, wherein respective recesses are arranged peripherally between the corner domes, and wherein the flanks of the corner domes are respectively provided at least partially with a radius.

Abstract: A wire printhead comprising a plurality of electromagnets and a corresponding plurality of armatures, each provided with an actuator arm forming, with the juxtaposed armature to an electromagnet, a lever of first order for actuating an impression wire attached to a free end of the actuator arm, said lever being biased to the rest position by a flexurally pre-loaded leaf spring acting on the lever in a predetermined position with respect to the lever fulcrum, through a resilient element which defines the point of application to the lever of the force from the leaf spring.

Abstract: Needle printing head of the permanent magnet type where the armatures of a plurality of printing actuators are attracted, in rest position, against the poles of a permanent magnet and released in printing position by the "cancellation" of the magnetic flux caused by control windings and where the impact of the armatures against the permanent magnet poles, when they return to the rest position is damped by a multilayer element interposed between armatures and magnetic poles and consisting in two thin sheets of magnetic steel between which a thin film of resilient material such as polyester is interposed.

Abstract: An armature group for mosaic printing head has a plurality of armatures wherein each armature which is part of an actuation electromagnet associated with one of a plurality of printing needles, is fixed to an elastic arm of a spring steel spider having as many arms as there are armatures. The spider, besides performing an armature positioning function allows the armature group to be handled as a unitary element which is easy to assemble. The thrust arm of each armature further has a double bend so that the plane between such arm and the corresponding needle head is perpendicular to the axis of the needle and passes through the fulcrum of the armature. This minimizes the buckling force which the needle has to undergo during the actuation phase. The construction of the armature group can be accomplished by a completely automated manufacturing process.

Abstract: An armature group for mosaic printing head has a plurality of armatures wherein each armature which is part of an actuation electromagnet associated with one of a plurality of printing needles, is fixed to an elastic arm of a spring steel spider having as many arms as there are armatures. The spider, besides performing an armature positioning function allows the armature group to be handled as a unitary element which is easy to assemble. The thrust arm of each armature further has a double bend so that the plane between such arm and the corresponding needle head is perpendicular to the axis of the needle and passes through the fulcrum of the armature. This minimizes the buckling force which the needle has to undergo during the actuation phase. The construction of the armature group can be accomplished by a completely automated manufacturing process.