Method and apparatus for the production of frusto-pyramidal can bodies
AssigneeElpatronic AG
InventorHerwig Schmidt
Life of this patent
Estimating the term…
Abstract
Circular cylindrical bodies (2) are formed from rectangular sheet-metal blanks by rounding and longitudinal seam welding. These are widened oval-conically over their whole length in a first expanding operation and then relaxed again. Then the bodies (2) are widened in a second expanding operation so that they acquire their polygon-like, particularly rectangle-like, cross-sectional shape over their whole length. As a result, the bodies are stressed at their marginal regions at the ends in such a manner that these marginal regions do not become undulatory and can therefore be satisfactorily joined with a can cover or bottom.
Claims16
A method of producing frustopyramidal can bodies from welded can bodies of a cylindrical shape comprising:
- forming a welded can body of cylindrical shape oval-conically over its whole length in a first forming operation which expands the body at one end and then relaxing the body again and then
- forming the oval-conical can body in a second forming operation so that it acquires a frustopyramidal shape with a polygon-like, particularly rectangle-like, cross-sectional shape over its whole length.
An apparatus for producing a frusto-pyramidal can body from a generally cylindrical body, said apparatus comprising:
- first forming means having a first mandrel for receiving said generally cylindrical body with said body generally overlying and circumscribing the first mandrel, said first mandrel being expandable and having a non-expanded state to receive said generally cylindrical body and an expanded state in which said generally cylindrical body is formed into an oval-conical shape;
- second forming means with a second mandrel for receiving said oval-conical body with the oval-conical body generally overlying and circumscribing the second mandrel, the second mandrel also being expandable and having a non-expanded state to receive the oval-conical body and an expanded state in which the oval-conical body is formed into a generally frusto-pyramidal shape, and
- transfer means for moving the body in the oval-conical shape from the first forming means to the second forming means for forming the body into the frusto-pyramidal shape.
A method for producing a frusto-pyramidal can body from a generally cylindrical can body, said method comprising the steps of:
- receiving the generally cylindrical body on a first expandable mandrel so that the body generally overlies and circumscribes the first mandrel;
- expanding the first mandrel to form the generally cylindrical body into an oval-conical shape;
- transferring the oval-conical body from the first mandrel to a second expandable mandrel so that the oval-conical body generally overlies and circumscribes the second mandrel, and
- expanding the second mandrel to form the oval-conical body into a frusto-pyramidal shape.
Dependencies are inferred from the claim text.