DEVICE FOR RETENTION, SCREWING AND UNSCREWING OF SELF-TAPPING SCREW Russian patent published in 2020 - IPC B25B23/10 F16B25/02 

FIELD: devices for retention.

SUBSTANCE: invention relates to devices for retention, screwing and unscrewing of self-tapping screw with tetrahedral head, diagonal of which coincide with direction of longitudinal axes of symmetry of slots. Proposed device comprises screwdriver, shell and spring. Inner surface of the shell is tetrahedral and can interact with the sides of the tetrahedral head of the self-tapping screw. In the bottom of the shell there is a square or hexagonal hole, in which a screwdriver is located, wherein the screw driver is equipped with two locking elements, one of which is located inside the shell, and the second one – outside the shell, between which there is a spring between the second locking member and the shell. And between the first and second lock elements the screw-driver is made as four-sided or hexagonal shape with the sizes ensuring its reciprocating movement in the square or hexagonal hole of the shell. Device is equipped with at least one resilient element located in a groove made on one of the sides inside the shell, wherein one end of the resilient member is rigidly connected to the shell, and other is made with C-shaped bend towards head of self-tapping screw for possibility of interaction with head of self-tapping screw, shell is provided with device to adjust resilient element pressing force against self-tapping head made up of bolt with lock nut arranged in shell threaded hole to interact with resilient element.

EFFECT: increased convenience of use, reduced efforts applied to a screwdriver at screwing and unscrewing of a self-cutter, possibility of unscrewing the self-tapping screw in case of falling into a knot and reduction of damageability of grooves of the self-tapping head.

1 cl, 4 dwg