Toggle overshot

Abstract

An overshot includes a sleeve. A coupling member having a latched state and an unlatched state is disposed at a first end of the sleeve. A load-responsive toggle mechanism for alternating the coupling member between the latched state and the unlatched state is disposed at a second end of the sleeve.

1 . An overshot, comprising:
 a sleeve;   a coupling member having a latched state and an unlatched state disposed at a first end of the sleeve; and   a load-responsive toggle mechanism for alternating the coupling member between the latched state and the unlatched state disposed at a second end of the sleeve.   
   
   
       2 . The overshot of  claim 1 , wherein the load-responsive mechanism comprises a first rotator for selectively engaging the coupling and a second rotator for selectively displacing and rotating the first rotator. 
   
   
       3 . The overshot of  claim 2 , wherein the load-responsive mechanism further comprises a weight member for applying a load to the second rotator that causes the second rotator to selectively displace the first rotator. 
   
   
       4 . The overshot of  claim 3 , further comprising a first spring member supporting the second rotator, and wherein the load is selected to overcome a biasing force of the first spring member. 
   
   
       5 . The overshot of  claim 4 , further comprising a second spring member supporting the first rotator, and wherein the load is selected to overcome a biasing force of second spring member. 
   
   
       6 . The overshot of  claim 3 , wherein the weight member is selectively movable relative to the sleeve to contact the second rotator and apply the load to the second rotator. 
   
   
       7 . The overshot of  claim 3 , wherein the second rotator is selectively movable relative to the sleeve to contact the weight member and receive the load from the weight member. 
   
   
       8 . The overshot of  claim 3 , further comprising a wireline connector coupled to the weight member. 
   
   
       9 . The overshot of  claim 2 , wherein the first rotator engages the coupling when the coupling is in the unlatched state and disengages from the coupling when the coupling is in the latched state. 
   
   
       10 . An overshot, comprising:
 an outer sleeve;   a coupling member disposed at a first end of the outer sleeve;   a first rotator disposed within the outer sleeve and configured to alternately engage and disengage from the coupling member, thereby toggling the coupling member between an unlatched state and a latched state; and   a second rotator disposed within the outer sleeve and configured to selectively displace and rotate the first rotator in response to an applied load; and   a weight member disposed at a second end of the outer sleeve for applying a load to the second rotator.   
   
   
       11 . The overshot of  claim 10 , further comprising an inner sleeve disposed within the outer sleeve. 
   
   
       12 . The overshot of  claim 11 , wherein the inner sleeve comprises a plurality of keys and the first rotator comprises a plurality of keys, and wherein the keys on the inner sleeve and the keys on the first rotator selectively come into contact to rotate the first rotator relative to the inner sleeve. 
   
   
       13 . The overshot of  claim 11 , further comprising a mechanism for selectively locking the first rotator to the inner sleeve. 
   
   
       14 . The overshot of  claim 13 , wherein the mechanism comprises a plurality of key slots on one of the inner sleeve and first rotator and a plurality of keys on the other of the inner sleeve and first rotator. 
   
   
       15 . The overshot of  claim 13 , wherein the mechanism further comprises at least one stop member coupled to the inner sleeve for selectively restricting motion of the first rotator. 
   
   
       16 . The overshot of  claim 10 , wherein the coupling member comprises a pair of lifting dogs pivotally mounted on an axle. 
   
   
       17 . The overshot of  claim 16 , wherein each of the lifting dogs has a first end for selectively engaging an article and a second end for selectively engaging the first rotator. 
   
   
       18 . The overshot of  claim 17 , wherein the coupling member further comprises a spring disposed between the second ends of the lifting dogs for biasing the second ends in opposing directions. 
   
   
       19 . The overshot of  claim 10 , further comprising a wireline connector coupled to the weight member for coupling the weight member to a wireline. 
   
   
       20 . A method of connecting or disconnecting a wireline from an article, comprising:
 providing an overshot comprising a sleeve, a coupling member having a latched state and an unlatched state disposed at a first end of the sleeve, and a load-responsive mechanism for alternating the coupling member between the latched state and the unlatched state disposed at a second end of the sleeve;   coupling a wireline to the load-responsive mechanism;   aligning the article with the coupling member; and   selectively activating the load-responsive mechanism to alternate the coupling member between the latched state where it engages the article and the unlatched state where it disengages from the article.   
   
   
       21 . The method of  claim 20 , wherein activating the load-responsive mechanism comprises applying or releasing tension from the wireline. 
   
   
       22 . The method of  claim 20 , wherein activating the load-responsive mechanism comprises moving the overshot upwardly.