Patent ID: 6183608
Filing Date: 2001-02-06
Classification: C01B

Abstract:
An electrode positioning mechanism, comprising:a reversible electric motor having a rotating drive shaft, said motor mounted on a support frame;a worm gear mounted on a gear shaft for rotation therewith, the gear shaft connected to said drive shaft for rotation therewith;said gear shaft mounted between a pair of supports on said frame for rotational movement on a rotational axis and axial slidable movement along the rotational axis;biasing means interposed between the supports and the worm gear for biasing the worm gear to a central location between the supports;a spur gear in operative engagement with said worm gear;an internally threaded collar having an axis affixed to said spur gear;an externally threaded sleeve coaxial with said internally threaded collar and having an axial opening therethrough and received by said internally threaded collar wherein rotation of said internally threaded collar about said axis causes the axial lengthwise movement of said externally threaded sleeve;an electrode positioned in said opening in said externally threaded sleeve for movement therewith;switching means connected to said reversible electric motor for reversing the direction of rotation of said drive shaft; andposition sensing means mounted on said frame, for detecting axial movement of the worm gear and shaft in first and second directions along the gear shaft axis;said position sensing means connected to said switching means to reverse the motor upon detection of movement of the gear shaft in the first or second directions.