| 摘要 |
PURPOSE: To save on human energy and time to be consumed for detecting a defective foldable mandrel by using a monitoring unit to detect the undesirable deformation of the foldable mandrel and assigning an error signal to the foldable mandrel having such a deformation. CONSTITUTION: When a deformation occurs which increases a distance between a foldable mandrel 11 and induction tracers 14, 15 the induction tracer 14 suffers no reaction by edges 18, 19 in the longitudinal direction. Consequently this induction tracer 14 has no switching action and therefore, a monitoring unit 13 generates an error signal. When the deformation occurs which reduces the distance between the foldable mandrel 11 and the induction tracers 14, 15, the edges 18, 19 in the longitudinal direction pass through the magnetic field of the second induction tracer 15, both induction tracers 14, 15 generate a signal. Thus the monitor unit 13 generates an error signal, so that the defective foldable mandrel 11 is easily specified. |
