GB1498522A - Pressure die casting - Google Patents

Abstract

1498522 Die casting apparatus FISHER GAUGE Ltd 6 Jan 1975 [31 Jan 1974] 410/75 Headng B3F In pressure die-casting apparatus, a locking member pivoted to the frame of the apparatus is engageable with the means effecting closure of the die to prevent movement of the die caused by the pressure of metal. The apparatus includes vertical and horizontal die closing units relating to the upper and lower parts of the die. The end plate 53 of cylinder 52 of die closing unit 17 carries a locking plate 94 having bearing pads 96 which are engaged by faces 336 of locking arms 306. The arm 306 is provided with a spring-loaded follower 342 engaging eccentric portion 310 of shaft 300. When the upper part (36) of die (26) (Fig. not shown) is in position, jack 324 is actuated to retract piston rod 322 which rotates shaft 300 and hence arm 306, the follower being located in a recess in the eccentric 310. When the stop 339 engages the side of the locking plate 94, further rotation of the shaft 300 forces the follower out of the recess and urges arm 306 towards the bearing pads 96 thus preventing upward movement of unit 17. Vertical die closing unit (Fig. 3).-The unit 17 comprises a cylinder 52 and rod 56 which has an annular piston 72 provided with a shoulder 78. With the upper die part held by flange 60, fluid is introduced through port 80 to lower the rod 56 (fluid escaping through ports 82, 64) until the shoulder engages recess 79 where fluid can only escape through smaller port 82, thus providing a cushioning effect in closing the die. Horizontal die closing unit (Fig. 6).-The lower die part is carried by bracket 212 attached to rod 210 of piston 204. With auxiliary piston 214 as shown, fluid enters port 230 passes through passages 234, surge chamber 226 and passage 238 to chamber 206, the fluid on the other side of piston 204 leaving through duct 237, chamber 216 and port 220. When piston 204 is fully advanced (as shown), fluid is introduced through port 218 to move piston 214 rearwardly, thus taking passages 234 out of alignment with port 230 and locking piston rod 210 in its fully-advanced position. The lower die part is held on bracket 212 by a rack and pinion mechanism (244, 246) (Fig. 7, not shown). A hydraulic sprue ejection mechanism (Fig. 5, not shown) also forms part of the apparatus.