Screw for introducing into an underground, comprising a screw shaft and a screw head which is adjoining the screw shaft, in which a drive is formed for rotary driving the screw by a drive element, wherein the drive comprises a hollow wing section at an outer side of the screw with a circular hollow core and hollow wings which are provided along the circumference, wherein the drive comprises a hollow recess section at an inner side of the screw, and wherein the drive at a transition between the hollow wing section and the hollow recess section comprises a chamfer section whose outer surface is angled with respect to an outer surface of the hollow wing section and with respect to an outer surface of the hollow recess section.

A fastener system includes a fastener and a driver, each of which have three alternating lobes and troughs that define the drive surfaces. The three alternating lobes and troughs are each defined by an outer radius portion, a drive side transition, an inner transition radius, and a reverse drive portion. The fastener recess and the driver each also have a side wall defined by the outer transition radius that tapers at a taper angle relative to the rotational axis. The fastener side wall may taper at about 60?. The driver side wall may taper at about 60?. Alternatively, the driver side wall may taper at an angle at least 10? less than the taper angle of the recess side wall, such as 42?. The drive side transition defines a drive angle which may be between 0? and 5?.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

The invention relates to a screwing tool with a longitudinal axis X comprising a first, drive part, which can receive torque, and a second, transmission part, which is designed to cooperate with a screw, in order to re-transmit to it the torque received, the second part having a conical peripheral envelope with three longitudinal concavities with conical generatrices, defining three identical radial transmission lobes, each of which has, in a cross-section perpendicular to the longitudinal direction, a distal tangential portion which extends according to an arc of a circle, and is extended on both sides by two connection portions, each of which is defined by a curve comprising a substantially radial main part, and having a point of inflection before re-joining a proximal joining region which ensures the joining with an adjacent connection portion. The joining regions have a cone angle which is smaller than the cone angle of the tangential portions, and is substantially less than 5, preferably less than 3.

A balancing device for a rotating part of a turbomachine, includes a ferrule pierced with a plurality of ports, a balancing screw passing through each port, each balancing screw including a body and a head, the head of each balancing screw being pierced with a recess, the balancing screws being of at least one first type, the recess of the screws of the first type being formed by a driving recess from which an additional recess extends.

Embodiments of the present invention provide a screw and driver system comprising a range of screws and a driver for said range. Each screw comprises a head having a driving recess in its surface for engagement by said driver. Each recess has a recess longitudinal axis. The recess of larger screws in the range has a plurality of superimposed recess-tiers of decreasing size with increasing depth from said surface, each recess-tier except the smallest having substantially parallel driving surfaces substantially parallel said recess longitudinal axis. The driving head of the driver has a driver longitudinal axis and a plurality of superimposed drive-tiers of decreasing size towards a tip of the driver, each drive-tier except the smallest having substantially parallel driving surfaces substantially parallel said longitudinal axis. The driver and recess are shaped so that, when the driver is engaged with the recess of any screw in said range, torque applied to the driver is transmitted to the screw through said driving surfaces. The smallest recess-tier of larger screws has a mouth in a floor of an adjacent recess-tier and has recess flanks that are all tapered from the mouth towards the recess longitudinal axis at a recess taper angle between 1.91 and 6.85. The smallest drive-tier of the driver has a root in a base of an adjacent drive-tier and has drive flanks that are all tapered from the root towards the driver longitudinal axis at a tier taper angle between minus 1.5 and plus 2.5 difference with respect to said recess taper angle. The diameter of the drive-tier at the root and the diameter of the recess-tier at the mouth are such that, on insertion of said driver head in the screw recess, said drive and recess flanks inter-engage to deform and stick together through frictional engagement before said base engages said floor.

The invention relates to a screw and corresponding screw driver for driving the screw into a dental implant at an angle from the longitudinal axis of the implant. The screw has a polygonal interface and the screw driver has a matching interface for driving the screw to rotate.

The invention relates to a screw (10; 70) with a shank (12), a thread (14) on at least one portion of the shank (12), wherein the thread (14) defines a screwing-in direction about a centre longitudinal axis of the shank (12), and with a drive formation (18; 78) at one end of the shank (12), wherein the drive formation (18; 78) has a depression (20; 80) in a screw head (16) or a projection at the end of the shank (12), wherein the depression (20; 80) or the projection in each case has a circular-cylindrical or frustoconical main body (22; 82), arranged concentrically with respect to a centre longitudinal axis (26) of the shank (12), and a number of protuberances (24; 84) which extend away from the main body (22; 82), wherein the protuberances (24; 84) are of rounded configuration at their radially outer ends, characterized in that the protuberances (24; 84) extend with a radial component with respect to the centre longitudinal axis (26), and with a component which is oriented tangentially and counter to the screwing-in direction.

A hollow screw and related process of making is provided, wherein the hollow screw is formed from a generally circular corrosion resistant stainless steel disk cut from flat roll stock. The hollow screw includes a head and an elongated and hollow shaft having a wall thickness between about 0.2 to about 0.7 millimeters extending therefrom and defining a shank portion and a threaded portion having a plurality of threads thereon with a rotational drive mechanism configured to facilitate tightening via the threads. The process involves annealing to soften the stamped hollow screw, followed by thread rolling, and then age hardening the hollow screw. As such, the resultant hollow screw is relatively lightweight, about 50% the mass of a solid core screw made from the same material, with a sufficient thread strength to meet most aerospace applications and contributes to important aircraft fuel economy.

A security fastener for installation on a wheel having a recess hole extending from a recess entrance of a first diameter comprising an end portion concentric with a longitudinal axis of the fastener, the end portion configured to mate with a corresponding element of the recess hole, an intermediate skirt portion having a side wall region with a diameter within about 6 millimeters of the diameter of the recess entrance, a drive portion having a tapered outer surface and a plurality of circumferentially spaced longitudinally extending key-receiving grooves in the tapered outer surface arranged in a lock pattern to which a driving torque may be applied, the tapered outer surface sloping downward and outward away from the longitudinal axis of the fastener from a top surface to the skirt portion at a taper angle of at least 11 degrees.