the yarn guiding the yarn onto and off of the pin by using pivoting or sliding guides that are worked by yarn tension and the yarn is displaced in a manner to shorten the yarn path thus displacing the measuring device until a point of entanglement is reached the distance between point of insertion and point of entanglement may be read out and the measuring process repeated many times without painstaking hand guiding operations application_number US 85042477 A description in accordance with this invention an apparatus and method has been created for performing a series of repetitions of an entanglement test very similar to the hook drop test but for performing the test much more rapidly than the hook drop test could be performed manually as instructed by bunting amp nelson the device is much less elaborate than those of hitt u s pat no 3 290 932 and rothschild but is much less expensive it may be less fully automated if desired it yields test results for bulked entangled carpet yarns consistent with reasonable expectation in controlled experiments e g making several sample tubes holding all variables constant except air pressure and on successive testings of the same tubes it may be made to provide greater measurement accuracy and to extend applicability of the device to very fine deniers the tester in accordance with this invention uses the length between sites rather than the number of sites per unit length principle the former is preferable not only because it permits calculation of more detailed information e g site distance variation as expressed by u03c3 and cv over a shorter yarn length than the latter principle but also because it is the principle employed by the manual hook drop method to users of.