Patent ID: 7831331

Claim:
An apparatus for detecting the position of a knife on a tufting machine, said apparatus comprising: (a) a grounded needle, said grounded needle being adapted to be moved between a penetrating position and a non-penetrating position; (b) an electrically-insulated knife, said electrically-insulated knife being adapted to be moved between a cutting position and a non-cutting position and being adapted to send a knife signal when the knife is in the cutting position and the needle is in the penetrating position; (c) a solenoid, said solenoid being adapted to receive a pattern signal prescribing either the cutting position or the non-cutting position for the electrically-insulated knife and being adapted to cause the electrically-insulated knife to move between the cutting position and the non-cutting position in response to the pattern signal and; (d) a programmable logic controller, said programmable logic controller being adapted to: (1) send the pattern signal to the solenoid; (2) receive the knife signal from the electrically-insulated knife; (3) compare the knife signal to the pattern signal; and (4) determine if the electrically-insulated knife is in the position prescribed by the pattern signal.