GB757634A - Improvements in or relating to sheet metal bending or cupping tools - Google Patents

Abstract

757,634. Bending and cupping dies. RUBERY OWEN & CO., Ltd. Feb. 2,1955 [Feb. 6, 1954], No. 3556/54. Class 83 (4). A sheet metal bending or cupping tool including a movable forming punch and a facing concavity of a die is characterized in that the forming punch comprises two separate members, namely, a punch nose to coact with the die to form the metal sheet into channel, trough or other concavity with upstanding edges and a punch body for bearing on the upper faces of the edges of the pressing at an appropriate pressure during the latter part of the forming operation whilst the punch nose partially withdraws into the punch body. The die 10 is secured to the press bed 11 and is provided with a mechanically, pneumatically or hydraulically operated ejector 12. A vertically reciprocable press ram 13 carries a bolster 9 to which is detachably bolted the punch body 14, and the punch nose 15 is slidably mounted for limited vertical movement in the body 14. The nose is held extended from the body 14 during the initial part of the forming operation by hydraulic pressure on a piston 17 which acts on the nose through a sleeve 18. A stripper 19 is arranged coaxially in the punch nose 15 and is hydraulically operated by a piston 20. In operation the stripper 19 first engages the blank 23 and holds it in position until the nose 15 begins the forming operation. Finally the punch body 14 travels downwardly (Fig. 3) and its operative face 25 engages the upper faces 24 of the edges of the formed blank 23a whilst the nose withdraws into the punch body. This pressure on the upper faces neutralizes the stresses which might otherwise cause distortion of the pressing. On withdrawal of the ram the stripper 19 removes the pressing from the punch. Alternatively, the punch nose and stripper are operated pneumatically or by a spring and the operative face 25 of the punch body is bevelled.