includes a housing 3 of which the latter possesses several here a total of two housing parts 5 and 25 the second housing part 25 is pivotable by means of a swinging arm 7 on a hinge 9 linked to the first housing part 5 forming thereby a cover by means of a hand grip 11 affixed to the second housing part 25 this second housing part 25 is pivotable upward out of its closed position which is designated with solid lines into an open position represented in fig1 by dotted lines the interlacing apparatus 1 includes moreover a yarn conduit 13 which penetrates the housing 3 which as said is comprised of the components 5 and 25 when the second housing component 25 is placed in its closed position then the yarn conduit 13 is circumferentially closed with the exception of the cross section of the opening of a not shown jet nozzle arrangement under these conditions only on the entry and exit openings of the yarn conduit 13 is the said conduit open in order to introduce a not shown in fig1 multifilament yarn into the yarn conduit 13 or to be able to take the same out without cutting it then the second housing part 25 is swung up so that the yarn conduit throughout its entire length is exposed the jet nozzle arrangement is connected by means of a feed piping line 14 with a source of the medium from which source the jet nozzle is supplied with a compressed medium preferably air the multifilament yarn is subjected to a flow of said medium that entwines its filaments together.