Aluminum Cable Presses for Billet Extrusion

In the manufacture of rubber-insulated cables or rubber hoses the lead sheath is applied for the vulcanizing process only. The sheathed cable or hose is coiled on drums which are placed in a steam-heated tank which is closed tightl3 with a lid. During vulcanization the hoses must be forced from their inside against the lead sheath. To achieve this, they are filled with hot water which at the vulcanizing temperature of 140 to 150 °0 attains a pressure of 4 to 5 atm. Upon completion of the vulcanization, the cable or hose is wound off the drum and passed through a stripp- 

The vulcanized hose retains the curvature of the drum after having been wound off and that is why this method is rarely employed in Germany at the present time. The method preferred now is that in which 

Requirements to be met by this kind of lead sheathing are very low as compared with lead sheathing as used for cables. In order to eliminate defects, the sheathing is furthermore extruded with a greater wall thickness as is usual for cable sheathing, as the lead is remelted. Should there be any defects, though, these may easily be remedied by soldering. 

On account of what has been said in the foregoing, these presses destined for the production of rubber-insulated cable and rubber hoses, may be charged with solid cylindrical lead billets instead of molten lead. Thus the solidification periods are eliminated and a substantial increase in production is achieved. 

The press of about 2,000 tons capacity is capable of extruding billets of 250 mm diameter and 1,100 mm length. The sequence of the charging operations may be automated by very simple means. A belt conveyor feeds the lead pigs into the melting kettle. The molten lead flows into two cylindrical molds from which the billets are alternately ejected through the top by a hydraulic ram. The billet is then placed in the container by a gripper which pivots with its arm round a column mounted at the side of the press. All of these operations are performed electrically and initiated from a control desk. 

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