A bolt includes a head portion on which a recess is formed. The recess has a bottom surface and a sidewall extending from a periphery of the bottom surface. The sidewall has a lower end defined by the bottom surface and includes an increased diameter portion and a reduced diameter portion. The increased diameter portion has an inner diameter larger than an inner diameter of the lower end of the side wall. The reduced diameter portion has an inner diameter smaller than the inner diameter of the increased diameter portion. The reduced diameter portion is located opposite to the bottom surface across the increased diameter portion.

A screw includes a threaded shank and a head with a first surface. Communicating sockets formed in the first surface include a Pozi-type socket and a drive socket. The drive socket includes rounded portions, arched portions alternating with the rounded portions, and a conical portion connected to the rounded portions and the arched portions to define a first reference line and a second reference line parallel to a central axis of the head. The rounded portions are inclined outwardly from the first reference line, and the arched portions are inclined outwardly from the second reference line. Thus, a first room enclosed by the rounded portions and the arched portions increases gradually towards the first surface. By a combination of the above sockets, the head cooperates with different driving tools for delivering driving force efficiently and is more convenient to use.

Fasteners, drivers, and fastener systems constructed wherein example fasteners have driver engageable surfaces on or within a shank tip of the fastener. Example embodiments are included where at least one of the installation and removal surfaces are configured to define a segment of a spiral. Some example embodiments are also included where the installation and removal drive surfaces intersect an enlarged core diameter in an inner transitional surface that extends between the installation and removal surfaces of adjacent wings. Embodiments include fasteners with installation and removal drive surfaces on or within a shank tip of fasteners.

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 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.

A fastener system includes a fastener and a driver, each of which have three alternating lobes and troughs that define the drive surfaces. Each alternating lobes and troughs is 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 a 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 method for connecting a screw and a rotary tool in a rotationally fixed manner, wherein the drive surfaces of the driving profiles have a constant inclination relative to their profile axis, which is the same for all drive surfaces of both components. In the component with the outer driving profile, the drive surfaces are all concave or all convex, and in the component with the inner driving profile, the drive surfaces are curved complementary to the drive surfaces of the outer driving profile, in such a way that, in the plugged-together state, the drive surfaces of the two components, viewed in the circumferential direction, come into surface contact/engagement with one another on both sides of the apex of the concave/convex curvature. The driving profiles are designed in such a way that they do not come into contact with each other in the transition regions located between the drive surfaces.

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 torque transmission driver has a first end portion adapted to receive and transmit torque from a torque generation source, and a second end portion including a shaped tapered bit having drive surfaces with an alternating series of five or six lobes and troughs about a rotational axis, having a taper angle between 15 and 45° from the rotational axis operable to engage corresponding drive surfaces in a plurality of at least two size fasteners, the tapered drive surfaces of the bit comprising a first tapered portion operable to engage drive surfaces of a first sized fastener and a second tapered portion operable to engage drive surfaces of a second sized fastener, the drive surfaces of the second sized fastener being larger than the drive surfaces of the first sized fastener.

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.