The invention is directed to a safety device for a machine that includes a first transceiver unit for emitting a first light beam in a first time slot and for receiving a second light beam. The safety device includes a second transceiver unit arranged for emitting the second light beam in a second time slot that is different from the first one. The safety device also includes an evaluation unit for determining a reflecting object between the first transceiver unit and the second transceiver unit, only if the first light beam is received by the first transceiver unit in the first time slot or the second light beam is received by the second transceiver unit in the second time slot. Additionally, a non-reflecting object may be detected, if by neither of the two transceiver units in both time slots one of the two light beams is received.
B21B 33/00 - Safety devices not otherwise provided forBreaker blocksDevices for freeing jammed rolls
B21B 38/00 - Methods or devices for measuring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
B26D 5/00 - Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
F16P 3/14 - Safety devices acting in conjunction with the control or operation of a machineControl arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine the means being photocells or other devices sensitive without mechanical contact
G05B 19/406 - Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
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