GB661517A - Improvements in or relating to an oil well derrick - Google Patents

Abstract

661,517. Masts for portable oil-well derricks. MOORE CORPORATION, L. C. Aug. 11, 1949. [Sept. 25, 1948] No. 20908/49. Class 78 (iv). The mast of an oil-well derrick comprises a lower section 18 pivoted at 8 to a substructure 1, and an upper section 17 which, when the mast has been lowered, may be disconnected at 19 from the lower section and telescoped into it. The mast is wider at the front than at the back and the front, at least of the lower section, is open so that the upper and lower sections may be nested, as shown in Fig. 9, by movement of rollers 23 on the lower section along tracks 21 on the back of the upper section. After its front legs have been removed the mast is swung, with the aid of the usual gin pole 16, to the prone position shown in Fig. 3 with the upper section resting on a truck. A bridle line passing over pulleys 31 on the upper section is connected at 28 to the lower section and to a line 32 from a winch 33. The truck is then backed toward the substructure 1 with the winch 33 in operation so that the rollers 23 pass up an inclined track 26 (Fig. 8) leading to the straight tracks 21 on the upper section. In the final position the front faces of both sections rest on the truck. A hook 27 at the end of the track 26 limits the movement of the rollers 23 when the mast is being assembled. The pivot 8 is mounted on a pair of arms 6 pivoted at 7 to the substructure and normally flush with its upper surface. A platform on the substructure and near the points of attachment 12 of the front legs may be removed to leave a well for receiving parts of the prone mast.