Mechanical trigger arrangement

Abstract

The present invention relates to an arrangement for the repeated mechanical triggering of various types of downhole equipment, the arrangement comprising a spring element ( 4 ) and a string section ( 1 ). The invention is characterized in that the arrangement comprises a rotary sleeve ( 7 ), with turning faces ( 1′, 1″; 2′, 2″ ) being provided between the string section ( 1 ) and the rotary sleeve ( 7 ), one set of the turning faces ( 1′, 1″ ) having an equivalent slope and the other set of turning faces ( 2′, 2″ ) having a different slope, the arrangement being configured to force a relative rotary movement between the string section ( 1 ) and the rotary sleeve ( 7 ) as a premise for an axial movement, with the amount of rotary movement of the rotary sleeve ( 7 ) depending on the force being applied to the arrangement, the stiffness of spring ( 4 ), as well as the slope of the turning faces ( 1\1″; 2′, 2″ ), the arrangement being configured to release the energy stored therein when the rotary sleeve ( 7 ) has been rotated by an amount causing the abutment face ( 3″ ) of the rotary sleeve ( 7 ) to no longer be axially abutted against the abutment face ( 3′ ) of an end piece ( 6 ), whereupon the rotary sleeve ( 5 ) and the string section ( 1 ) will be displaced relative to the end piece ( 6 ) allowing the spring ( 4 ) to release its stored energy.

1 - 4 . (canceled) 
   
   
       5 . An arrangement for repeated mechanical triggering of an impact hammer, the arrangement comprising a string section ( 1 ) rotationally restrained and axially movable relative to an end section ( 96 ), a rotary sleeve ( 7 ) rotatable around the string section ( 1 ) and a compressible spring ( 4 ) disposed between the end piece ( 6 ) and a pre-tension element ( 3 ,  5 ) on the string section ( 1 ),
 characterized in that the rotary sleeve ( 7 ) comprises
 an abutment face ( 3 ″) along part of its circumference in a plane perpendicular to its axis of rotation, 
 a first turning face ( 1 ″) adapted to a corresponding first turning face ( 1 ′) spiral along a first part of the string section ( 1 ), 
 a second turning face ( 2 ″) adapted to a corresponding second turning face ( 2 ′) spiral along a second part of the string section ( 1 ), 
   that the rotary sleeve ( 7 ) in a first position is oriented such that the abutment face ( 3 ″) engages a corresponding abutment face ( 3 ′) along part of the circumference of the end piece ( 6 ), that the first turning faces ( 1 ′,  1 ″), upon axial displacement of string element ( 1 ) towards the end section ( 6 ), interact to cause a rotation of the rotary sleeve ( 7 ), that the rotary sleeve ( 7 ) in a second position is oriented such that the sleeve abutment face ( 3 ″) is rotated past the extent of abutment face ( 3 ′) on the end piece ( 6 ), thereby triggering release of potential energy from the string ( 4 ) and providing an impact to the end piece ( 6 ),   that the rotary sleeve ( 7 ) in a third position, axially displaced from the second position, is configured to engage the second turning face ( 2 ′) of the string section ( 1 ) along the corresponding turning face ( 2 ″) on the rotary sleeve ( 7 ), and that the second turning faces ( 2 ′,  2 ″), upon being forced together by residual spring force from the spring ( 4 ), interact to cause a further rotation of the rotary sleeve ( 7 ) back to the first position.   
   
   
       6 . The arrangement of  claim 5 ,
 characterized in that the string section  1  and rotary sleeve  7  in the released third position, is freely moveable in both axial directions without causing any significant resistance.   
   
   
       7 . The arrangement of  claim 6 ,
 characterized in that the rotary sleeve  7  in the released third position is freely rotatable around the string section  1  to the first starting position without causing any significant resistance.   
   
   
       8 . The arrangement of  claim 5 ,
 characterized in that the tensioning resistance of the arrangement is determined by the amount of pretension in the spring, the stiffness of the spring ( 4 ), and the slope of the turning faces ( 1 ′,  1 ″;  2 ′,  2 ″).