Patent GB-519146-A (GB)
Title: Improvements in and relating to apparatus for trueing surfaces by grinding
IPC: B24B53/04
Filed: 1938-09-30
Abstract: 519,146. Grinding. BREVETS AEROMECANIQUES SOC. ANON. Sept. 30, 1938, No. 28507. Convention date, Aug. 17, 1938. [Class 60] Apparatus for trueing up the internal surfaces of the cartridge chamber of guns, or of nozzles, &c. wherein the surface is formed by two truncated cones of different apex angles, namely, the surfaces A, B which intersect in the plane O, comprises a grinding wheel 3 having a cylindrical surface A<1> and a conical surface B' including the same angle a as do the surfaces A', B<1> the wheel being fed axially into the chamber with the axes' of the' wheel and the gun making an angle # equal to one half the apex angle of the surface A. The wheel is fed axially a predetermined distance and the chamber is then tested by a plug gauge having thereon a mark showing when it has been inserted the correct distance ; if necessary the wheel is given transverse feed and further cuts, made again by axial movement the predetermined distance, are given. The wheel is trued, between cuts if necessary, by removal of material by diamonds 46, 47 so as to retain the angle a between the surfaces A<1>, B<1> and to retain the intersecting' plane O<1> of the surfaces in the same axial position; the wheel is tested for accuracy in the cartridge chamber of a dummy gun having a part cut out to allow of viewing the wheel when in the chamber. A machine for effecting the above operations comprises a frame 5, on which is pivoted at 17 a plate 10 having pivoted thereon, about spindles 9, a support 4 having bearings 4<1>, 4<2> in which the work 2, shown as a gun, is rotatably mounted, a shoulder 2<1> on the gun being pressed against the bearing 4<1> by a spring-pressed thrust ball bearing 6. The gun is rotated by a pinion 11 fitted to the gun and driven by gearing 12-16. The angle # is set by adjustment of the plate 10 -about the pivot 17, a locking pin 18 securing the plate in position, and the support 4 may be swung about the pivots 9 to allow of gauging &c. the work, by a toggle 20, 21 a spring 22 moving the support to grinding position as determined by a micrometer screw 23 on the support and a fixed surface 10, on the plate. The grinding-wheel 3 is mounted on a part 27 rotatable in a support 28 and having a part 27<1> slidably keyed to a pulley 29; the support 28 being adjustable axially by a screw 31 on a plate 30, which is reciprocated axially of the wheel by a cam 34 and a spring 33, the cam being driven from a shaft 40 provided with a clutch permitting of hand or power actuation. The diamonds 46, 47 are respectively carried by parts 48, 49 slidable in guides 50, 51 at an angle a to each other, in a plate 52 pivoted at 53 to a carriage 54 adjustable to and from the wheel 3 by a micrometer screw 55 on a base 54<1> carried by the support 28. The diamonds are reciprocated by a lever 56 pivoted at 57 to the plate 52 and operated by a handle 58 through an eccentric pin 59 and a slot 60 in the link, the link carrying fingers 61, 62 engaging notches 63, 64 in the parts 48, 49. The base 54 is adjustable, parallel to the axis of the wheel 3, by a screw 65.