Swing arm for actuating magnetic head and casting mold for the same

Abstract

A swing arm for actuating a magnetic head having a multiplicity of extremely thin blade of 0.9 mm in thickness that has been difficult to produce in a conventional casting may be produced by die-casting. Fixed cores and movable cores are disposed in a casting space provided in a parting line between a fixed core and a movable core. A body casting space and a blade casting space are set. A cross-sectional area of an overflow gate provided at an end of the blade casting space is greater than a cross-sectional area of a runner gate for connecting a runner and the body casting space. At the same time, a weight of the overflow material overflowed from the overflow gate to the molten material storage portion is set to be greater than a weight of a product portion filled in the casting space. The flow of the molten material to the blade casting space that is narrow is made smooth.

What is claimed:  
     
         1 . A casting mold for casting a swing arm for actuating a magnetic head in which a plurality of plate blades for supporting magnetic heads are provided around a sleeve-shaped member pivoted about a pivot in a multiplicity of stages, wherein the swing arm is die-cast of aluminum alloy and the blades have a thickness of less than 1.05 mm; and 
 a cross-sectional area of an overflow gate provided at a terminal of a blade casting space is set to be greater than a cross-sectional area of a runner gate provided in a body casting space and a volume of a molten material storage portion connected to the overflow gate is set to receive the overflow of a greater weight of the molten material than a weight of a product portion.    
     
     
         2 . The casting mold for casting the swing arm according to claim  10 , wherein the overflow molten material storage portion is in communication with a chill vent in communication with an evacuation means.  
     
     
         3 . The casting mold for casting the swing arm according to claim  10 , wherein a heating circuit for causing thermal medium to flow is provided in and around the body casting space and the blade casting space.  
     
     
         4 . The casting mold for casting the swing arm according to claim  10 , wherein the thickness of the blades of the swing arm is in the range of  0 . 85  to  0 . 95  mm; and 
 a cross-sectional area of an overflow gate provided at a terminal of a blade casting space is set to be greater than a cross-sectional area of a runner gate provided in a body casting space and a volume of a molten material storage portion connected to the overflow gate is set to receive the overflow of a greater weight of the molten material than a weight of a product portion.  
 
     
     
         5 . The casting mold for casting the swing arm according to claim  13 , wherein the overflow molten material storage portion is in communication with a chill vent in communication with an evacuation means.  
     
     
         6 . The casting mold for casting the swing arm according to claim  11 , wherein a heating circuit for causing thermal medium to flow is provided in and around the body casting space and the blade casting space.  
     
     
         7 . A The casting mold for casting the swing arm according to claim  14 , wherein a heating circuit for causing thermal medium to flow is provided in and around the body casting space and the blade casting space.