Spacing device for objects conveyed through an operating machine, in particular for cardboard box closing/and or sealing machines

Device for spacing of objects conveyed through an operating machine, in particular for cardboard box closing and/or sealing machines, said device comprising means sensitive to the passage of a first object and at least one retaining member placed upstream from said sensitive means in the direction of travel of the objects and caused by said sensitive means to move tranversely to said direction of travel to achieve a retaining engagement with a second object until achievement of a desired distance from the first object characterized in that said sensitive means comprises a belt entrainment unit having a spreading section, a lever having a first portion pivoted on the spreading section engaging with the sides of the objects conveyed to cause travel through the machine and said retaining member comprises a passive stopping means mounted on a second portion of said lever so as to be moved toward the interior of the machine when said first portion is moved outward by the passage of a first object and vice versa, there being provided first elastic means acting on said spreading section of said entrainment unit to stress it in a yielding manner toward a condition of alignment with the remaining part of said unit and second elastic means acting on said lever to stress it in a yielding manner into a waiting position in which said first portion is moved toward the interior of the machine and said second portion is moved toward the outside of said machine.