An operating wheel of a packing machine (1), having an annular drum (3); a number of through pockets (8) carried by the annular drum (3) and each for receiving a relative product (21); first drive means (18) for rotating the annular drum (3) in steps to feed the pockets (8) along an annular path (P) extending through a loading station (23) and an unloading station (25); first and second push means (53, 44) for engaging respective pockets (8) at the loading station (23) and the unloading station (25) respectively; second electric drive means (56, 47) for imparting to the push means (53, 44) respective substantially radial reciprocating movements to and from respective withdrawn rest positions inside the annular drum (3) and through the respective pockets (8); a first safety device (58) for preventing the annular drum (3) from rotating when at least one of the push means (53, 44) engages a respective pocket (8); and a second safety device (59; 80) for preventing the push means (53, 44) from moving from the respective withdrawn positions when the annular drum (3) is rotating.