Multiple casting apparatus and method

Abstract

Apparatuses and methods of forming battery parts are disclosed herein. In one embodiment, a method of forming a battery part includes receiving a flowable material into a cavity, and reducing a volume of the cavity while a pin extending through at least a portion of the cavity remains at least generally stationary therein. The method further includes sealing the cavity by slidably engaging at least a portion of the pin with a recess in the piston proximate the end face of the piston.

I/we claim: 
     
         1 . An apparatus for die cast battery part when the molten lead is in either the liquid, solid or mush state to form a finished battery part:
 a mold having a set of faces for defining a portion of an outer surface of a battery part cavity;   a pin having a face thereon, said pin extending through the battery part cavity to form an inner face of a battery part cavity;   an inlet for delivering lead in a molten state into the battery part cavity;   a heater for maintaining the lead in a molten state when the lead in a molten state is not being delivered into the battery part cavity;   a retractable piston, said retractable piston having a battery part face thereon for forming the battery part cavity into a closed volume, said battery part face extending in a side-to-side condition to adjoin the set of faces in the battery part cavity, said retractable piston positionable in a first condition to allow the lead in a molten state to flow into the battery part cavity, said retractable piston driveable toward the battery part cavity to close the volume of the battery part cavity to thereby shut off the flow of the lead in a molten state into the battery part cavity and to decrease the closed volume of the battery part cavity by bringing the battery part face toward the battery part cavity to shrink the volume of the battery part cavity without disrupting a faces on a solidifying battery part solidifying therein to produce the battery part with an exterior finished surface.   
     
     
         2 . The apparatus of  claim 1  wherein the retractable piston has a cavity for sliding along a pin and the pressure of the lead within the battery part cavity is increased sufficiently to thereby form a battery part whereupon solidification is substantially free of tears and cracks. 
     
     
         3 . The apparatus of  claim 1  wherein the battery part face comprises an annular face. 
     
     
         4 . The apparatus of  claim 3  wherein the entire battery part face extends along a single plane. 
     
     
         5 . The apparatus of  claim 1  wherein the lead in a molten state is a lead alloy. 
     
     
         6 . The apparatus of  claim 1  the heater extends around the inlet to maintain the lead in the inlet in a molten state when the extendible piston is in an extended condition. 
     
     
         7 . The method of die casting a finished battery part while inhibiting the formation of cracks and tears comprising the steps of:
 directing a first charge of lead in a molten state into a battery part cavity having at least one open face;   extending a retractable piston having a battery part face into the charge of molten lead in the battery part cavity to shut off the supply of molten lead to the battery part cavity; and   continuing to extend the piston to form a closed battery part cavity and to reduce the volume of lead in the battery part cavity to a sufficient volume so that upon solidification of the lead in the battery part cavity it inhibits the formation of cracks and tears in the battery part.   
     
     
         8 . The method of  claim 7  wherein the lead in the battery part cavity is in either a liquid, mush or solid state. 
     
     
         9 . The method of  claim 8  wherein the molten lead solidifies along the surface faces of the battery part cavity with at least one of the battery part faces is forced inward to reduce the volume of the battery part cavity. 
     
     
         10 . The method of  claim 9  including the step of heating the first mold part with a heater to maintain the mold in a runner in a molten state. 
     
     
         11 . The method of  claim 7  wherein a portion of the lead in a runner is back flowed therein to bring the molten lead in the battery part cavity to an intensification condition. 
     
     
         12 . The method of die casting a finished battery part comprising the steps of:
 injecting a molten lead containing metal into a battery part cavity having a first volume defined by a set of mold faces; and   decreasing the first volume of the battery part cavity by forcing at least one of the mold faces toward the battery part cavity to decrease the peripheral surface area while the molten lead in the battery part cavity is at least partially in an unsolidified state; and   maintaining the decreased volume during a solidification of a battery part in the battery part cavity to thereby inhibit the formation of cracks and tears in a die cast battery part.   
     
     
         13 . The method of  claim 12  wherein the battery part cavity is formed with a cylindrical interior surface and an annular end face.