Dual shiftable needle bars for tufting machine

In a tufting machine having means for supporting a base fabric for longitudinal movement in a feeding direction through said machine, a patterned stitching mechanism comprising:

• (a) a first elongated needle bar having a plurality of first needles spaced along said first needle bar,
• (b) a second elongated needle bar having a plurality of second needles spaced along said second needle bar,
• (c) means supporting said first and second needle bars parallel to each other on one side of the base fabric moving through the machine and transversely of said longitudinal feeding direction, for independent reciprocal movement longitudinally of said needle bars, and for reciprocable movement toward and away from the base fabric to cause said first and second needles to reciprocably penetrate the base fabric,
• (d) pattern-controlled actuator means operatively connected to said first and second needle bars to shift said needle bars independently of each other in predetermined increments transversely of said feeding direction,
• (e) yarn supply means supplying first yarn to said first needles and second yarn to said second needles, and
• (f) needle drive means for reciprocably moving said needle bars toward and away from the base fabric to cause said needles to stitch said yarns through the base fabric in accordance with the pattern determined by said pattern-controlled actuator means.