GB566442A - Improvements in or relating to adjustable reamers and like tools - Google Patents

Abstract

566,442. Reamers. ENGLISH STEEL CORPORATION, Ltd., and ARCHER, J. Aug. 12, 1943, No. 13042. [Class 83 (iii)] In an adjustable reamer of the type having an open-ended socket with' slotted walls in which cutter blades are radially adjustable by conical surfaces on a plug movable axially in the socket and wherein the blades are locked by bevelled surfaces or abutments associated with the socket engaging similar surfaces on the blades, a rear abutment is movable axially but not rotatably relative to the socket by a differentially screwed sleeve engaging threads of different pitch on the' abutment and the socket. In one form, the socket 11, Fig. 2, has axial slots 16 for the blades 15, the bases of the slots being bridged by portions 17 which form a cylindrical bearing for the plug 18, having conical portions 19, 20 engaging similar projections 21, 22 on the blades. The socket is slidably keyed on a shank 12 by a transverse pin 13 engaging axial slots 14 therein and has a screw-thread 25 engaging an internal thread on a sleeve 26 which is also internally threaded to engage a screw 28 on the shank of different pitch from the screw 25. In operation, the sleeve 26 is rotated to move the socket axially until bevelled surfaces 23 on the bridges 17 are in position to engage similar surfaces on the blades when these have been adjusted to the required diameter as indicated by scales on the sleeve and shank, the plug 18 then being screwed by its stem 18<1> into the shank to force the blades against the surfaces 23 and also against an abutment surface 24 on the end of the shank. In another form, which is similar to the reamer described in Specification 552,077, the socket 11, Fig. 4, is formed integral with the shank 12 and the bases of the slots for the blades 15 are bridged by two axially displaced portions 17, 17a. An abutment sleeve 31 is slidably keyed at 33 to the shank and is moved axially thereon by a differentially screwed sleeve 26 engaging threads 25, 28 of different pitch on the sleeve 31 and shank 12 respectively, until a bevelled abutment surface 30 on the sleeve 31 is situated at the correct distance from bevelled surfaces 29 on the socket to locate the blades at the desired diameter as indicated by the scale on the sleeve 26. The plug 18 is then screwed into the shank to force the blades outwardly against the bevelled surfaces and so lock them in the required position. The blades may be arranged with their medial planes coincident with radii of the reamer or displaced from these positions, or the blades may be arranged helically.