GB747245A - Improvements in folding gin poles for oil well masts - Google Patents

Abstract

747,245. Raising derrick masts. MOORE CORPORATION, L. C. July 26, 1954 [Jan. 20, 1954], No. 21788/54. Class 78 (4). A gin pole 8, 13 automatically unfolds from the position shown in broken lines in Fig. 1 as it is raised by force applied to a portion of the leg 8 extending below its pivot 7. As illustrated, the unfolding is effected by tension links 23 connected between points 24 on the shoes 3 and members 19 secured to the legs 13 and embracing the legs 8. A pin-and-slot connection 20, 22 between the legs 19 and the links 23 ensures that unfolding starts only after the legs 8 have been raised to an angle of about 45 degrees. The gin pole is raised by a sling 26 secured to the lower ends of the legs 8 and passing around vertical and horizontal pulleys 27, 28 to the travelling block 5 which is drawn towards the crown by a drilling line 30 which passes over a central pulley 31 on the gin pole and so restrains its final movement into engagement with shoes 16. Movement of the gin pole past this position is prevented by engagement of the lower ends of the legs 8 with plates 37 on the shoes 3. The mast 1 is subsequently raised about pins 2 on the shoes 3 by a sling 32 which passes from the travelling block 5 over pulleys 34, 35 in the mast and over spaced pulleys 33 on the gin pole to be secured to the mast.