the vertical position each screw 21 is positioned coaxial with a respective housing 55 of a rotary push device 56 for feeding as explained in detail below an orderly succession of subgroups 18 from accumulating station 26 to input portion 37 of conveyor 28 of belt conveyor 27 for this purpose housings 55 rotate in opposite directions and each comprise on the side facing respective screw 21 a respective number of peripheral axial pins 57 equally spaced about relative axis 22 and projecting from housing 55 towards accumulating station 26 each pin 57 moves through accumulating station 26 in time with a relative pin 57 on the other housing 55 to transfer subgroups 18 successively from accumulating station 26 to belt conveyor 27 on cartoning machine 1 transfer of packets 4 from belt conveyor 27 to packing device 14 along plate 38 a is controlled by a push device 58 comprising a linear electric motor 59 in turn comprising a stator which is defined by a rail 60 extending parallel to output portion 38 of conveying branch 30 and located below output portion 38 and plate 38 a and to the side of belt conveyor 27 and a movable assembly 61 mounted to slide along rail 60 movable assembly 61 comprises an upright 62 and a rail 63 integral with the top of upright 62 extending crosswise to direction 17 and along which runs a slide 64 of a powered l shaped pusher 65 comprising a paddle 66 as slide 64 moves along rail 63 paddle 66 is moved between a withdrawn position of non interference and a forward position of interference with path p 1 along which packets 4 are fed in feed direction 17 to packing device 14 in a variation not shown paddle.