Improvements in or relating to jars for use in well-boring

摘要

224,398. Vickers, Ltd., and Vickers, D. Dec. 19, 1923. Bore-hole apparatus.-Jars for use in well-boring have one member A formed with a number of longitudinal slots a and the other member B formed with a number of longitudinal projections b1 registering with the slots. The member A is preferably tubular and is suitably provided with a bell mouth a2, Fig. 7, to permit insertion of the part B, the bell mouth being then closed into sliding engagement with the cylindrical part b2 of part B. The tubular part A may have an extension A3, Fig. 7, forming a guide for a cylindrical lower extension of the part B: apertures a4 permit escape of accumulated material.