in their projecting positions or by providing a cam operated mechanism to draw the pins in the thread may be sprung over the ends of the pins 42 as they are retracted if it is held by hooks or notches 44 such as are shown in fig4 it may be desired however to rotate the pins eg by a cam mechanism operating on an arm 78 fig4 of each pin at the moment of transfer to facilitate the release of the looped thread from the third roller whatever way the transfer is effected it is preferable to ensure that by this stage the thread has been drawn taut into the loop pattern assumed in the finished tea bag it is particularly desirable to locate as precisely as possible the ends 8a 8b that pass through the passages 16 in the upper edge seal 14 in order to keep the width of the passages to a minimum forming the loop patterns with the thread may require significant variations of velocity of the thread as it emerges from the wand it is desirable to ensure that accelerations imposed on the thread do not lead to excessive tension loads fig6 illustrates a thread feed mechanism for limiting thread tension which comprises a motorised drive device 80 drawing the thread 8 from a bobbin 82 through an entry guide eyelet 84 downstream of the drive device the thread runs in an open loop 8 39 depending into the outer end of a suction tube 86 a central barrier.