STEM HOLDER Russian patent published in 2010 - IPC B23B31/22 B23B51/12 

FIELD: process engineering.

SUBSTANCE: device allows connection of drill bit to drill revolving part and comprises socket and stem. Said socket can be attached to revolving part. Socket and stem can be interjointed, while stem can be secured to drill bit. The latter retainer engages with lock grooves made on stem side surface, when stem is jointed to socket, to stop its axial travel from the socket. First engaging part made on socket engages with first part to be engaged with made on the stem to transmit torque from the socket to stem. Note that stem stays in contact with socket to stop its axial travel to the socket. Socket comprises fastening shaft jointed to drill revolving part. Fastening shaft tail top has larger-diametre part jointed with socket base body by screw. Stem can be jointed to socket via hole. Drill bit centering hole communicated with stem fastening hole is made on socket base body. Locking screw hole runs from outer peripheral surface of base body to centering drill bit outer peripheral surface in direction perpendicular to centering drill bit fastening hole. Locking screw engages with locking screw holes. Note that its top end penetrates into centering drill bit joint hole. Larger-diametre part covers, at least, a section of locking screw to prevent its falling out toward base body outer side.

EFFECT: transmission of higher torque at reduced sizes.

5 cl, 9 dwg