motion 10 are mounted on the free end of a support arm 11 which extends outside the storage drum 1 and parallel to the axis thereof the upper end of the support arm being mounted in the housing 2 mounted on the support arm 11 directly below the withdrawal edge 1a of the storage drum 1 is a hook 13 which is normally in the position shown in fig1 when in this position it engages the area of the running off thread f 39 the hook is open in the direction of rotation p of the storage drum 1 the running off thread f 39 which tends to rotate about the withdrawal edge 1a of the storage drum 1 in the opposite direction of rotation to that of the drum as a result of the tension acting thereon in the direction of withdrawal is therefore inserted into the hook opening and prevented by the hook 13 from moving any further laterally around the withdrawal edge 1a therefore only the same amount of thread can be withdrawn as is released by the drum as a result of its rotation in the direction p the withdrawal speed of the thread is thereby limited to its wind on speed this is the normal mode of operation for the thread feeder which is intended primarily for positive thread delivery alternatively the hook 13 can.