Method and device for deep drawing blanks made of sheet metal into flangeless moulded blanks
AssigneeSaeta GmbH & Co. KG
InventorThomas Haar
Life of this patent
Estimating the term…
Abstract
A method for deep drawing blanks, which are punched out of sheet metal that is painted or coated with film material, for example made of steel or aluminum, into flangeless molded blanks, wherein the blanks are formed to a crucible-shaped part, with a flangeless cylindrical edge, around a drawing core by means of a drawing bell of a drawing die, and a predetermined spring force is applied to the side of the edge opposite to the drawing bell during the forming of the edge of the blanks by means of a blank holder, characterized in that the spring force applied to the blank holder is spontaneously reduced substantially to zero shortly before the end of the drawing process.
Claims14
A drawing die for deep drawing blanks which are punched out of sheet metal that is painted or coated with film material into flangeless moulded blanks comprising a drawing bell, a drawing core, a blank holder and a pneumatic spring which applies a spring force to the blank holder, wherein the pneumatic spring is formed by a gas volume in a chamber (30), which is sealingly closed by a piston (28), wherein the piston bears against the blank holder (22) by way of force transmission elements (24), and a venting valve (38) is associated to the chamber (30), wherein the venting valve (38) is actuated when the piston (28) arrives in a predetermined position, whereby the chamber (30) is suddenly vented.
An apparatus for forming flangeless molded blanks from sheet metal that is painted or coated with film material, said apparatus including:
- a) a drawing bell;
- b) a drawing core;
- c) a blank holder;
- and
- d) a pneumatic spring that applies a spring force to said blank holder, said pneumatic spring being formed by a gas volume in a chamber, which chamber is sealingly closed by a piston;
- said piston being in engagement with said blank holder via force transmission elements;
- a venting valve is associated to said chamber which is actuated when said piston moves to a predetermined position whereby the chamber is suddenly vented such that the spring force on the blank holder is substantially eliminated.
A drawing die for deep drawing blanks which are punched out of sheet metal that is painted or coated with film material into flangeless moulded blanks comprising a drawing bell, a drawing core, a blank holder and a pneumatic spring which applies a spring force to the blank holder, wherein the pneumatic spring is formed by a gas volume in a chamber (30), which is sealingly closed by a piston (28), wherein the piston bears against the blank holder (22) by way of force transmission elements (24), and a venting valve (38) is associated to the chamber (30), wherein the venting valve (38) is actuated when the piston (28) arrives in a predetermined position, whereby the chamber (30) is suddenly vented such that the spring force applied to the blank holder is reduced to substantially zero.
An apparatus for forming flangeless molded blanks from sheet metal that is painted or coated with film material, said apparatus including:
- a) a drawing bell;
- b) a drawing core;
- c) a blank holder;
- and
- d) a pneumatic spring that applies a spring force to said blank holder, said pneumatic spring being formed by a gas volume in a chamber, which chamber is sealingly closed by a piston;
- said piston being in engagement with said blank holder via force transmission elements;
- a venting valve is associated to said chamber which is actuated when said piston moves to a predetermined position whereby the chamber is suddenly vented such that the spring force on the blank holder is substantially eliminated, and wherein, just before the completion of the drawing process, the blank is positioned on the blank holder substantially without pressure.
Dependencies are inferred from the claim text.