DEVICE WHEREBY A DUCT IN A DEEP BORE HOLE IS SUPPORTED AND MOVED UP OR DOWN BY REACTION AGAINST THE HOLE SURFACE

A duct section or other load to be moved axially along a bore hole has two reciprocating drivers mounted on it and two sets of gripping elements. Each driver reacts axially between the load and a set of gripping elements to move the gripping elements relative to the load through a defined stroke in each axial direction. An endless cable with axially extending straight stretches has one stretch connected to each driver to constrain the drivers always to move in opposite axial directions and to begin and end their strokes simultaneously. The gripping elements are so formed that when engaged with the surface of a bore hole, increasing axial force on the load in one direction increases the radially outward force under which they bite into the surface. At each end of a driver stroke the gripping elements collide with abutment members of a direction control device, whereby gripping elements engaged with the bore hole surface are forced out of such engagement and disengaged gripping elements are forced against that surface. The abutment members are arranged in two sets, one set to coordinate gripping element engagement and disengagement for transporting the load in one axial direction, the other set for transportation in the opposite direction. Positioning the directional control device at one or the other limit of its rotation brings one or the other set of abutment members into use.