1344893-A2 is referenced by 34 patents and cites 4 patents.

The invention provides a substantially constant force actuator that is applicable to centralizers, anchors and tractors for use in wells and is applicable to lifting devices such as jacks and load supporting devices. One or more sets of linkage arms are angularly movable by the force of one or more force transmitting members from a minimum angle with the force transmitting members at maximum spacing to a maximum angle with the force transmitting members at minimum spacing to impart a substantially constant force to an object or surface, with the direction of the force being substantially perpendicular to the direction of relative linear movement of the force transmitting members.; With the linkage arms at their minimum angles, movement control elements on at least one of the force transmitting members react with guide surfaces of the linkage arms to achieve angular linkage movement and to develop a substantially constant force during angular linkage movement.

Title
Constant force actuator
Application Number
EP20030251356 20030306
Publication Number
1344893 (A2)
Application Date
March 6, 2003
Publication Date
September 17, 2003
Inventor
Cordera F Joseph
US
Roy Carl J
US
Post Roger A
US
Sheiretov Todor K
US
Assignee
Schlumberger Technology
NL
Schlumberger Holdings
VG
Schlumberger Services Petrol
FR
IPC
E21B 47/08
E21B 23/01
E21B 17/10
E21B 23/04
E21B 47/00
E21B 17/00
E21B 04/00
B66F 07/00
B66F 03/00
E21B 23/00
E21B 47/08
E21B 23/01
E21B 17/10
E21B 04/18
B66F 07/00
B66F 03/22
B66F 03/12
E21B 23/04
View Original Source Download PDF