Patent ID: 8545139
Filing Date: 2013-10-01
Classification: B25H,Y10T

Abstract:
1. A magnetic drilling stand comprising: a base; a drilling unit received on said base; an electromagnet received on said base for fixing said magnetic drilling stand on a component, said electromagnet having a rated current I N ; an controller for controlling operation of said electromagnet and of said drilling unit; a voltage source controlled by said controller and coupled to said electromagnet; a sensor for monitoring a current through said electromagnet and for generating a current signal I indicative of a current flowing through said electromagnet and for outputting said current signal to said controller; wherein said controller first powers said electromagnet for a certain test phase of a duration T, before operating said drilling unit and generates either an OK signal indicative for a sufficient magnetic holding force or a fault F signal indicative for insufficient magnetic holding force, depending on the current level signals at different times within said test phase; wherein said controller generates said OK signal when, after 30% of the duration T of said test phase has elapsed, a current level of said electromagnet of at most 85% of said rated current I