bobbin doffing position of the bracket when the required yardage has been wound on the bobbin the machine as a whole is signalled to decelerate e g by means of a yardage counter microprocessor and a brake motor 94 see fig1 when a positioner 69 see fig7 on the heart cam gear wheel 53 reaches a proximity switch 66 the brake motor 52 is signalled to stop at which point the cam follower 55 is in the dwell of the heart cam and the bobbin carriage 23 is therefore in its lowest winding position wherein the sliver is wound around the bobbin at the topmost part of its barrel the rest of the machine which is driven independently of the brake motor 52 but which is synchronized with it continues to decelerate the signal from the proximity switch 66 also starts a further brake motor 67 to rotate the screw 59 in a direction such that the bracket 58 which is threaded on to it is driven downwardly the pivot end of the traverse lever 56 is lowered and its opposite end raised this causes the lifting brackets 24 and bobbin carriage 23 to move downwardly below their lowest traverse position until a positioner 65.