GB462257A - Improvements in and relating to devices for gripping tubes or pipes in well drilling operations - Google Patents

Abstract

462,257. Supporting tubes &c. in wells. NATIONAL SUPPLY CORPORATION, and OIL WELL ENGINEERING CO., Ltd. Sept. 5, 1935, No. 24738. Convention date, March 5. [Class 85] A device for gripping a tube or pipe in well drilling operations comprises slips 2, 3 movably arranged in a body 1 and retractable to release the tube or pipe and means for yieldingly maintaining said slips in either the gripping or retracted position. The slips are pivoted at 9 to arms 8 integral with sleeves 7 journalled on shafts 5, 6 and integral with arms 11, 12 pivoted to a link 13. The arm 12 has an actuating handle 14 and springs 17, 20 are mounted between stationary abutments 16, 19 and pivot pins 15, 18 respectively connecting the parts 11, 13 and 12, 13, the springs being so positioned with respect to the centres 22, 21 of the shafts 5, 6 that the effective line of tension of the springs passes over such centres during movement from the gripping to the retracted position. The slip engaging seat 4 of the body 1 comprises parts 4a, 4b engaging seating portions 33a, 33b of the slips in the gripping position and recesses 34, 35 to receive the portions 33a, 33b in the retracted position. The lower parts of the slips have substantially point-engagement at 39a with the part 40 of the seat during movement and the arms 8 are of such length and are so positioned that the slips are maintained substantially vertical during movement. In a modification, Fig. 7, the lower parts of the slips have point contact at 101 with the part 102 of the seat. In a further modification, Fig. 8, links 103 are provided to ensure that the slips remain vertical during movement. Specification 287,889, [Class 85], is referred to.