GB939040A - Drilling apparatus - Google Patents

Abstract

939,040. Drilling machine details. T. D. WILLIAMSON Inc. Dec. 29, 1960 [Jan. 14, 1960; Oct. 13, 1960], No. 44613/60. Class 83 (3). [Also in Group XXIV] Apparatus for drilling a hole in a fluid pressure main without interrupting the flow, comprises a housing mountable on the main, a drilling spindle in the housing, means for feeding the spindle in response to relative rotation between the spindle and housing, which includes a slipping coupling to allow a greater rate of feed during movement of the spindle towards the work, than the actual drilling feed. The apparatus comprises a housing 10, Fig. 2, a drilling spindle 11 connected to a bush 17 rotatable in the housing, having a drill 12 secured thereto, a non-circular driving shaft 15 carried in a similar shaped bore 16 in the spindle and a feed nut 19 rotatable on the spindle. Nut 19 carries spring-urged balls 25 at 24 which engage in dimples in a member 22 keyed to spindle 11, thus forming a friction clutch. In operation, housing 10 sealed at 32, 33 against escape of fluid from the main, is screwed into a flange 10a, Fig. 1, and the latter is bolted to a valve 35 carried by a branch 36 on main 37. Shaft 15, along with spindle 11 is rotated by e.g. a motor 38, and clutch 22, 24, rotates feed-nut 19 at the same speed, thus feeding drill 12 up to main 37. As drilling commences, the clutch will slip, thus reducing the feed rate. Balls 25 may be replaced by projections fixed to clutch part 24, and parts 22, 24, can be made to reciprocate relative to each other. An adaptor for securing the apparatus to different sized valves may be provided for connecting to housing 10. In a modification, Fig. 5, spindle 11 has a thread 50 which engages with spring- urged balls 51, to provide the drill feed or the balls may be provided in the spindle, with the thread in housing 10. In a further modification, Fig. 7, spindle 11 is rotated by a handle 70 carried by a non-circular portion 71 on the spindle and a sleeve 73 screwed to housing 10, is axially fixed relative to the spindle by a thrust bearing 74, and a nut 72. An adjustable spring- urged plunger 76 in the handle engages depressions 75 in the sleeve so that on rotation of the handle, sleeve 73, and drill 12 will be axially fed until the drill engages the main, whereupon handle 70 will slip, and the feeding rate will be reduced. Housing 10 has a scale 79, which, when read in conjunction with the end of sleeve 73, indicates the depth of cut. The depth of cut is indicated in Fig. 2, by a graduated dip-stick 40.