ELLIPTIC THREAD OF ANDROSOV-GREBENIUCK Russian patent published in 2010 - IPC F16B33/02 

FIELD: machine building.

SUBSTANCE: elliptic thread consists of projections and recesses alternating on cylinder surface of rotating body; said projections and recesses are made along spiral line formed by pitch and angle of ascent. In axial cross section a projection and recess are formed with two semi-circles conjugated by average diametre of thread; radii of semi-circles correspond to one fourth part of axial thread pitch; centres of their semi-circles are set off relative to each other at value of half-pitch of thread. At normal cross section the projections and recesses are made with conjugated semi-ellipses with radially arranged big semi-axes equal to radius of the said semi-circle. Tangent of angle of ascent of spiral line in axial cross section is determined by ratio of axial pitch to length of circle of average diametre of thread. Dimension of small semi-circle of ellipse is equal to product of radius of the said semi-circle by cosine of angle of ascent of spiral line.

EFFECT: elimination of stress concentrators in thread.

2 dwg