| 摘要 |
1351298 Forging dies M P FABREGAT 19 April 1971 [4 April 1970] 26214/71 Heading B3H [Also in Division F2] A wiper ring assembly for a piston comprising a split metal wiper ring 7 urged outwardly by a split annular expander spring 9 housed in a groove 8 in its inner periphery is made by diepressing a split metal ring, one die section being arranged to restrain the external periphery of the ring and the other having a disc portion 5 provided with an annular outwardly extending projection 14 which, when the die assembly is closed as in Fig. 1, forms the groove 8, removing the split ring 7 from the die assembly and housing the spring 9 in the groove. The die assembly comprises an upper platen 1, to which the disc 5 is attached, a lower platen 3, a die ring 2 and a centring ring 4. The ring 7 is formed prior to die-pressing from copper or copper alloy bar which is rolled or drawn to size, cut into required lengths and curved to form a split ring. When the die sections are separated, the ring 7 remains attached to the projection 14 and is then removed manually. The groove 8 may be of semicircular, triangular or rectangular cross-section and the spring 9, which is of steel, may be of circular, triangular or rectangular cross-section. In a modification the platen 3 is provided with radial recesses 18, Fig. 12, to form radial oil passages in the ring. |
