COMBINED DRILL BIT WITH MECHANICAL FASTENING OF ROCK DRILLING UNIT ELEMENTS Russian patent published in 2019 - IPC E21B10/14 E21B10/20 

FIELD: soil or rock drilling; mining.

SUBSTANCE: group of inventions relates to combined drill bits and method of their production. Combined drill bit comprises: housing with several blades, each of which contains several rock-destructing elements; at least one pocket for a rolling assembly located between adjacent blades in the housing and comprising a first mechanism responsive to torque; at least one roller assembly comprising a blade to which a cutting element is movable and which comprises a second mechanism responsive to torque and capable of functionally engaging a first torque response mechanism; and several holes for mechanical fasteners. Bit comprises also: several mechanical fasteners made for reliable and detachable connection of at least one roller assembly to the pocket; a fixing joint made on a part of at least one fastening element and capable of providing interference fit between the locking joint and the fastener element associated with it in the leg; several fixing covers, each of which is capable of engaging with the protruding part of the corresponding fastening element to prevent relative turn between the fastening element and the cover; and a number of welded parts catching at least part of each fixing cover and capable of preventing each locking cover displacement relative to the corresponding fastening element and preventing relative turn between each cover and body. Each of the welded parts is located between adjacent fixing covers to connect them.

EFFECT: technical result consists in improvement of bit reliability by means of welding exclusion with blade or bit body to prevent fastening elements loosening.

24 cl, 5 dwg