GB851124A - Cup-shaped articles and process of forming same - Google Patents

Abstract

851,124. Making pistons; extruding; jointing by forging. BENDIX AVIATION CORPORATION. Oct. 23, 1958 [Nov. 29, 1957], No. 33986/58. Classes 83 (2) and 83 (4). [Also in Groups XVII and XXVI] A method of manufacturing a bimetallic cupshaped article, e.g. a piston for use in the hydraulic brake systems of automobiles, from a metal slug and a metal insert of less ductile metal than the slug comprises placing and aligning said insert on said slug, confining 9 'the-bottom- and sides of said slug and pressing said insert into said slug to cause the metal of the slug to flow outwardly at right-angles with respect to the direction of applied pressure and also parallel with respect to said direction to form a cylindrical side wall and to embrace the marginal portion of said insert. The discshaped steel insert 16 is strengthened by an annular rib 22 on its upper surface and a corresponding annular groove 24 on its lower surface. A central recess 26 engages with a protrusion 40 on the plunger 34 to assist in centring the insert on the aluminium blank 44 placed over the extrusion die cavity 32. In operation, the metal of the blank 44 is extruded upwardly between the edge of the insert and the diecavity and flows inwardly above the insert until arrested by the plunger to secure the insert in the bottom of the extruded cup-shaped article. An ejector 42 is raised to remove the workpiece from the die. In a modification, a flat disc-shaped insert is used with only a central recess corresponding to the recess 26.