EXPANDER Russian patent published in 2017 - IPC E21B7/28 

FIELD: mining.

SUBSTANCE: invention relates to drilling equipment and is designed for wellbore enlargement under the casing string shoe. The expander comprises a housing with through grooves where blades set with hard alloy are positioned on the axes, spring-loaded piston with a central rod and the expanding taper at the end which coacts with blades, provided with a casing with longitudinal slots designed symmetrically to the through grooves of the housing and connected to them with thread, taper surface is provided with aring lug facing the annular cavity in the body of the housing and with longitudinal grooves on the taper surface designed symmetrically to the longitudinal slots of the casing. The taper surface position is fixed by retaining mechanism connected to the central rod. The blades are designed with a projection and mounted for its butt contact with the taper surface in the longitudinal grooves and the casing in the extreme position of the blades.

EFFECT: invention provides reliability improvement of drilling equipment operating.

3 dwg