FIXING DEVICE FOR EARTH DRILL AND EARTH DRILL SYSTEM WITH SPECIFIED FIXING DEVICE Russian patent published in 2013 - IPC E21B25/02 E21B23/02 

FIELD: mining.

SUBSTANCE: fixing device comprises at least one latch made as capable of detachable retention of an insert device in a substantially fixed axial position relative to an outer pipe, a cam and a tracking element designed to control radial position of the latch. Besides, the latch at its first longitudinal edge is equipped with an engagement surface adapted for engagement of the latch seat, has the second longitudinal edge opposite to the first longitudinal edge, and is made as capable of rotation around the axis of rotation on the first end of the latch, and a cam is installed on a substantially opposite second end of the latch in the axial direction and has a withdrawal surface, along which the tracking element may move to withdraw the latch in order to unfix the insert device from the external pipe. Besides, the withdrawal surface stretches from the near section of the cam to the far section of the cam, and the tracking element is made as capable of displacement relative to the withdrawal surface from the first end of the cam nearest to the axis of rotation to the second end of the cam, the furthest from the axis of rotation. The withdrawal surface on the second end of the cam is arranged closer to the first longitudinal edge than in any other point on the cam, and the cam and the tracking element are arranged so that the highest value of the ratio between substantially transverse force acting for movement of the latch from the fixation position and substantially axial force acting to move the insert device in the axial direction relative to the external pipe, is achieved in the start or near the start of movement substantially in axial direction between the cam and the tracking element.

EFFECT: possibility to move displacement and withdrawing force on latches.

22 cl, 8 dwg