Sealing arrangement for a movable insert for a die casting mold having a retractable core

#This invention relates to movable inserts for a die-casting mold and more particularly to such inserts which incorporate a movable core and still more particularly to sealing between the movable insert and the retractable core.

#An earlier invention, as described in U.S. Pat. No. 5,862,853 which issued on Jan. 26, 1999, comprises a movable insert for a die-casting mold having a cavity in which a core is mounted and slidable between a retracted position in the cavity and an extended position in which the core extends from the movable insert.

#FIG. 1 is a sectional view through a prior art die-casting mold assembly, generally indicated by reference 10 for casting a part 12 having an opening or boss 14 extending therethrough which is non-parallel to a “machine direction” indicated by arrows 16. The opening 14 is narrower at a point 16 part way along its length than it is toward either end.

#Preferred embodiments of the present invention are described below with reference to the accompanying drawings in which:

#FIG. 1 is a sectional view through a prior art die-casting mold assembly;

#FIG. 2 is a sectional view through a prior art movable insert having a retractable core which is illustrated in a retracted position;

#A movable insert for a die-casting mold according to the present invention is generally indicated by reference 50 in FIGS. 4 and 5. The movable insert 50 includes a cavity 52 having substantially parallel sides. In most cases the cavity sides 54 will be cylindrically disposed however this is not an absolute requirement.

#A retractable core 56 is slidably mounted in the cavity 52 for movement between a retracted position, as illustrated in FIG. 4, and an extended position, as illustrated in FIG. 5. In the retracted position, the retractable core 56 is substantially housed within the movable insert 50 and does not extend therefrom. In the extended position the retractable core 56 extends from the movable insert 50 to present a mold face 58.

#A connector 60, described in more detail below, is provided on the retractable core 56 for releasably connecting the retractable core 56 to a locator 62 which moves the retractable core 56 between its extended and its retracted positions.