The present invention relates in general to safety devices and in particular to a safety device for a roll space of a calender or similar roll machine having a beam in front of the roll space that is transverse to the rolls on the calender and substantially parallel to the roll space.
A prior art safety device is described in DE 37 19 305 C1. In such a device, the beam consists of a carrier provided with protection bars that can be moved closer to the individual rolls that form the roll space in order to satisfy applicable safety standards. Accordingly, the space between the safety device and the rolls that define the roll space should not exceed 8 millimeters (mm).
Another prior art safety device is described in DE 40 30 150 C1. In that device, the bars need not be moveable with respect to the carrier, but rather may be fixedly connected to the carrier or integrally formed therewith.
Prior art safety devices tend to undergo undesirable oscillations during start-up periods or during normal operation when the rotational frequency of the rolls coincide with the resonant frequency of the devices. The magnitude of the oscillation in the middle of the beam can approach or exceed 10 mm. Therefore, safety problems in the work place may result due to the increased clearance between the rolls and the beam.
It is an object of the present invention to improve the safety effectiveness of a safety device for a roll machine.