the way when desired as while changing the warp beam and instantly and accurately retured to said optimum operating position by means of a positive stop which positions the warp stop motion mechanism in said optimum operative position automatically without further attention by the operator except to tighten the few bolts necessary to hold the warp stop motion mechanism in said optimum operating position application_number US 12910580 A description referring more specifically to the drawings a weaving loom generally designated by the reference numeral 10 includes a frame 11 which supports a warp beam 12 extending transversely across the rear of the loom 10 individual ends of warp yarn only one of which is indicated at y for purposes of illustration are drawn from the warp beam 12 across a whip roll 19 and through a stop motion mechanism broadly indicated at 13 enroute to the weaving instrumentalities not shown on the loom 10 the stop motion mechanism 13 includes a drop wire 14 for each warp yarn y supported about electrodes 15 and between separator bars 16 the electrodes 15 and separator bars 16 extend transversely across the rear of the loom and are supported between spacer blocks 17 there being a block 17 of desired thickness between adjacent electrodes 15 and separator bars 16 fig7 to maintain them in desired spaced relation each spacer block 17 has an opening 18 therethrough to slidably receive a threaded rod 20 having a free end 21 over which the blocks 17 are threaded preparatory to clamping the electrodes 15 and separator bars 16 between the blocks 17 end blocks 22 are also threaded on the threaded rods 20 to support the.