| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a safety device for easily and safely determining over-travel in a machine with cost effectiveness, and to provide its method. <P>SOLUTION: The safety device is provided for a press brake 10 in which upper tools 12, 20 execute working motion 18 toward lower tools 14, 24. It comprises a first optical barrier 32 and a second optical barrier 33. Two optical barriers 32, 33 are moved together with the upper tools 12, 20 during the working motion 18, and the first optical barrier 32 extends first distances d<SB>1</SB>, d<SB>2</SB>ahead of the upper tools 12, 20 and the second optical barrier 33 is arranged second distances d<SB>8</SB>, d<SB>9</SB>apart from the first optical barrier 32. When the first optical barrier 32 is shut off, the working motion 18 of the upper tools 12, 20 is stopped. When the upper tools 12, 20 are stopped once, whether the second optical barrier 33 is shut off or not is checked. Depending on the result of the check, the working motion is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
