GB434476A - Improved grinding machine, more particularly suitable for the precision finishing ofthe nose of armour piercing shells - Google Patents

Abstract

434,476. Grinding armour-piercing shells &c. TERNI SOC. PER L'INDUSTRIA E L'ELETTRICITA, Terni, Italy. Nov. 30, 1933, Nos. 33591 and 33592. Void [Abridged as open to inspection under Sect. 91 of the Acts, June 15, 1934]. [Class 60] The improved grinding-machine is designed particularly for finishing the curved points of armour-piercing shells, but is of general application for work of similar shape. The machine, though primarily concerned with grinding the point to the precise ogival curve required, includes also means for finishing the fore ring to required diameter and a turning necessary for parts of the exterior. Forming part of the grinding equipment are means for setting the grinding tools and means for checking the finished work. A device for handling the shells into and out of position is also included. In view of the lack of clearness of the Specification nothing beyond a bare outline of the machine and its operation can be usefully attempted. Figs. 2, 2a show a longitudinal elevation, Figs. 22, 22a a cross section and Fig. 25 a part plan. The fixed headstock 1 contains motor means for rotating the chuck 4 and for driving the reciprocating and feed mechanism for the main carriage 5 through the medium of the shaft 15. Upon the carriage 5 is mounted the fore-ring grinder 39, Figs. 22a and 25, and the curved-point grinder 27, the carrier of which is mounted for rotation about an axis O which, in the appropriate setting, coincides with the centre line O, Fig. 1, from which the ogival curve Pd of the shell point is struck. The movable headstock comprises an assembly 16, Fig. 2a, consisting of a carriage A supporting a poppet and gauge holder B and, above that, two aligned arms C, each having shell-carrying blades 78. The location of the axis O (about which the carriage of the point grinder 27 moves) in relation, more particularly to the diameter of the fore ring D, Fig. 1, is dealt with at length, as also the procedure for ensuring the removal, in the grinding operation, of a minimum of material. The axis O is located by aid of the ordinates b, a of the point O, Fig. 1, referred respectively to the shell axis X1, X1 and the plane Y1, Y1 passing through the shell tip P at right angles to the axis. For dealing with each of these measurements two alternative gauges are employed. One of these, for the ordinate b, is indicated at F in Fig. 22a, while for the ordinate a a plane surface is employed, defined in part by a disc 73 magnetically positioned at the left hand end of the poppet arm B, Fig. 2a, and moved so as to touch the shell point P, in conjunction with one or other of two length gauges (one of these latter is shown at 50, 51, Fig. 2.) Special gauging means are also employed for obtaining the correct diameter of the fore ring. The shell is secured to the rotary headstock by an axial holder, Fig. 4, fitting its cavity and having a screwed base Q, in conjunction with a lock nut V and packing- rings R, S, T. A finished shell is removed by loosening its connection with the headstock, then running the assembly 16 to the left so that the blades 78 on one of the arms C engage the shell and then rotating the headstock so that the shell unscrews onto the blades, whereupon the assembly 16 is withdrawn and the arms turned through 180‹, thus bringing the finished shell clear for removal and presenting a fresh shell, on the other arm, to the headstock. The machine includes a snap-over reversing mechanism for traversing both the carriage 5 and the rotary carriage for the grinder 27 and means for trueing the grinders without material interruption of the work.