Scott C Ferguson

US Patent:

43412700, Jul 27, 1982

Filed:

Jun 16, 1980

Appl. No.:

6/160048

Inventors:

Scott M. Ferguson - San Francisco CA

Assignee:

Great American Development Co. - San Francisco CA

International Classification:

B23Q 500
E21C 500
B23B 5027

US Classification:

173151

Abstract:

Improved means for suspending a drill string using a pair of hydraulically actuated belts is disclosed. A derrick or tower is mounted to a base to overlie a standard rotary drill table. The drill string (comprising a number of drill pipes and a drill collar) and a drill bit are suspended within the hole being drilled by a hook. A hook support rides between a pair of vertical guide rails and supports the hook between the rails via a pair of belts which engage the hook support. The belts extend from the hook support, to the stationary pulleys at the top of the tower, and down to an alternating series of stationary and movable pulleys which define a variable length path along which the belts are guided. When it is desired to raise or lower the hook, and therefore the drill string therefrom, the hydraulically actuated, movable pulleys are either raised or lowered to change the length of the variable length path and consequently the length of belt along the path.