Apparatus for measuring the amount of yarn withdrawn from a warp beam of a warp knitting machine

An apparatus for measuring the amount of yarn withdrawn from a warp beam of a warp knitting machine having a frame supporting the warp beam, and comprising a support arm pivotally mounted on the frame, a lever arm pivotally mounted on the support arm and extending toward the warp beam, a pressure roller rotatably supported on the lever arm for engaging peripheral yarns wound on the warp beam and rotating with the warp beam as the yarn is withdrawn, a signal generator operatively connected to the pressure roll so that as the pressure roll rotates, pulses are generated representative of the length of yarn withdrawn from the warp beam, a limit switch mounted on the support arm and adapted for electrical connection to a main drive mechanism of the warp knitting machine, said limit switch having a first position and a second position and adapted for controlling operation of knitting machine so that when the switch is in the second position the knitting machine is operative and when the switch is in the first position the knitting machine is inoperative, and wherein said support arm is pivotally movable into

• a) a biased, operative position pivoted toward a warp beam in which the pressure roll is engaged with the warp beam and the limit switch is in the second position;
• b) an intermediate position in which the support arm is pivoted away from the warp beam, the limit switch is in the first position, and the pressure roll is engaged with the warp beam;
• and
• c) an inoperative position in which the support and lever arms are pivoted rearwardly from the warp beam and the pressure roll is disengaged from the warp beam and the limit switch is in the first position;
• wherein upon movement of the support arm from the inoperative position to the operative position the pressure roll engages the warp beam before the limit switch is switched to the second position, and wherein upon movement of the support arm from the operative position to the inoperative position the pressure roll continues to engage the warp beam after the limit switch is switched to the first position.