COMBINATION OF FASTENING ELEMENT WITH SLOTTED HEAD AND SCREWDRIVERS Russian patent published in 2018 - IPC F16B23/00 

FIELD: instrument engineering.

SUBSTANCE: invention relates to a fastening element and is aimed at improving the reliability of torque transmission. Fastening element comprises a head, a slot with a central recess in the head, further comprising three radially extending grooves terminating in the head of the fastening element, the central recess comprising a lobed inner zone, having three lobes with a maximum circumscribed circumference, located on the same axis as the imaginary center of the radial grooves; Radial grooves are formed from a truncated cone, the central axis of which extends at an angle to an axis parallel to the axis of the fastening element and forms an inner tapering angle of the slot that tapers inward, which leads to the appearance of elliptical and narrowing inward sections with the deepening of radially extending grooves in the head of the fastening element; and an additional central part of the recess, made in the form of a truncated cone, which terminates on the inscribed circumference of the lobe inner zone.

EFFECT: invention is aimed at increasing the reliability of torque transmission.

12 cl, 13 dwg