GB613486A - Improvements in or relating to a dimpling tool - Google Patents

Abstract

613,486. Dimpling. MARTIN CO., G. L. June 20, 1946, No. 18570. Convention date, June 26, 1945. [Classes 83 (iii) and 83 (iv)] [Also in Group XXV] Spinning ; drills.-A tool for forming a dimple about a hole in sheet metal comprises a pressure member for initially engaging the work, axially movable rotary dimpling means adapted to spin over the edge of the hole, means carried by the dimpling means for removing burrs and means controlling the extent of axial feed of the dimpling means relatively to the said pressure means. A shank 7 adapted to be gripped in the chuck 8 of a drilling machine has a lower internally threaded hole into which is screwed the dimpling or spinning element 14, surrounded by sleeve 17 formed with cutters 18 for removing burrs thrown up by the spinning operation. The element 14 has a pilot pin 16 and radial ribs 15 which serve to spin over the edge of the metal into an opening in a former or anvil 9. Supported on the shank by means of thrust bearings 32, 30 is a hollow body 30 urged towards the forming element 14 by a spring 24 and carrying at its lower end a pressure pad 22 with a lower concave surface adapted to operate with the upper convex surface of the anvil to grip and slightly flex the sheet before it is engaged by the spinning tool. The extent of the dimpling is controlled by means of a stop nut 26 on the upper part of the shank which is adapted to engage a thrust bearing 35 carried in a depression at the top of the body 30. The nut may be accurately adjusted by the aid of a scale 39 on the shank and is split so that it can be clamped on to the shank in adjusted position. The position of the forming element 14 relatively to the shank may be adjusted by means of shims 19.