Method and apparatus for monitoring a press

PCT No. PCT/SE82/00175 Sec. 371 Date Jan. 12, 1983 Sec. 102(e) Date Jan. 12, 1983 PCT Filed May 17, 1982 PCT Pub. No. WO82/04010 PCT Pub. Date Nov. 25, 1982.In a method and an apparatus for safe-guarding a press (1) by monitoring the press motion, use is made of the fact that the force exerted by the press is an almost invariable function of the position of the upper press platen in relation to the lower press platen. The force exerted by the press is continuously sensed during each pressure stroke by means of transducers (6). The instantaneous value of the force is compared in a monitoring unit (10) with a reference force value, calculated during the first pressure stroke, at each one of the subsequent positions of the upper press platen of the press in relation to the lower press platen thereof. This comparison is repeated for each such position during the pressure stroke. The monitoring unit (10) directly interrupts the press motion if, on comparison, the sensed force value in any position deviates from the reference force value by more than a predetermined amount. As a criterion for directly interrupting the press motion, also the off-line position of the upper press platen may be utilized.