| 摘要 |
A guard means for machines, more particularly pressbrakes, guillotines, stamping machines and the like in the case of which a first machine part (10) performs working movements toward a second machine part (11). Between the machine parts a photoelectric detector arrangement {19 and 20) is positioned and is attached to the moving machine part (10), a stop means being adapted to halt working motion of the moving machine part on interruption of a light beam. A control means for the working movement of the moving machine part (10) reduces the speed immediately prior to light beam interruption by the other machine part (11) to below a threshold limit speed.By means of a speed measuring means (25 and 26) the working speed is measured and the stop means is deactivated below the predetermined threshold limit speed at least partially in order to be able to complete the working movement even in the case of interruption of the light beam by the other machine part (11). Such a speed measuring means may be also fitted externally to existing plant in a simple manner. |
