Pre-rounding element on a rounding apparatus

摘要

A pre-rounding element (14) is used in a rounding apparatus (4) for rounding can body blanks from sheet metal blanks. The lower element part (22) of the pre-rounding element (14) is displaceable by an actuation element (23). This allows the adjustment of the pre-rounding element even during operation of the rounding apparatus. Preferably a measurement of sheet metal blank properties takes place. The measurement may include a thickness measurement and/or a strength measurement of blanks. The pre-rounding element is controlled in dependency of the measurement result. This allows a constant rounding result even with varying sheet metal properties.

主权项

1. A method of rounding sheet metal blanks in a rounding apparatus in which each blank to be rounded is pressurized by a pre-rounding element, said pre-rounding element comprising a fixed element upper part with fixation elements for fixation to the rounding apparatus, or said upper element part being provided by a fixed part of said rounding apparatus, a lower element part being provided for acting on the sheet metal blanks, a joint or hinge, respectively, joining said element upper part with said element lower part, at least one actuator by which said element lower part is displaceable controlled by a signal and wherein said signal is based on a measurement of a sheet metal property of the sheet metal blanks to be rounded,
wherein said sheet metal property is a rounding property of said sheet metal blank which is measured during operation of said rounding apparatus on consecutive blanks without destruction of said blanks, and wherein said rounding property is measured electrically by detecting said passing blank at a first position, pre-rounding said blank, detecting said blank at a second position dependent from the rounding and measuring the time of travel of said blank between said first and said second position.