GB779465A - Apparatus for bulging hollow metal blanks to shape in a mold and control mechanism therefor - Google Patents

Abstract

779,465. Stamping. AMERICAN RADIATOR & STANDARD SANITARY CORPORATION. May 5, 1955, No. 13077/55. Class 83 (4). A machine for bulging tubular metal blanks comprises a two part die, runners in said die parts for receiving the ends of a blank, means for moving the movable die part to or from the other die part, means for holding the movable die part against the other die part when the parts are closed, hollow sealing members having tapered ends spaced to align with said runners, means for actuating the tapered ends of the sealing members into the respective ends of the blank, means for supplying liquid into said blank through one of the sealing members and discharging the liquid through the other sealing member to scavenge air from the blank and sealing members, timing means for shutting off said discharge when the liquid has flowed a predetermined length of time through said blank, and means for displacing volumes of said liquid into the blank to effect the bulging operation. The machine comprises a base 4 supporting a platen 5 which adjustably carries the lower part 6 of the die. The upper die part 8 is carried by a platen 7 secured to the pistonrod 9 of a piston 10 which clamps the die parts together. A piston 20 working in a cylinder 15 is connected to the rod 9 and is operated to move the platen 7 to or from its closed position. The upper portion of cylinder 15 is housed in a tank 29 which contains liquid sufficient to fill, through a valve 291, the space above piston 10 as it is being moved downwardly by piston 20. When piston 10 has reached its die closing position the valve 29<SP>1</SP> closes, whereupon only a small volume of fluid is required to effect the die clamping. To open the die parts fluid pressure is applied to the underside of piston 20. The bulging fluid is supplied to the blank through tubular sealing members 32 and 33 having tapered ends for inserting into the ends of the blank. Shoulders 321 and 331 on the sealing members abut the ends of the blank and the sealing members are simultaneously actuated by pistons 36 and 37 respectively. Valves 46 and 47 mounted on rams 34a and 35a respectively provide for scavenging the workpiece of air. Valves 46 and 47 contain spring-loaded fluted valves 51 and 69 respectively, the valve 69 being capable of being unseated by a piston 70 (Fig. 6). When the workpiece has been scavenged and filled with liquid the operating pressure to piston 70 and the supply pressure to inlet part 66 of valve 46 are cut off and the closed valves trap the liquid in the workpiece, ram 34a and the sealing members. The bulging pressure is supplied by the ram 75 working in the hollow ram 34a. When a predetermined volume of liquid has been displaced into the workpiece pressure is applied to part 40 of cylinder 38 to feed a predetermined length of workpiece lying in the runner 30 into the die. Bulging and infeed may be carried out in stages with intermittent heat treatment. The above described cycle is effected by a control system [Group XXIX].