Patent Number: 
Section: claims

1. An electron beam sterilization unit for processing food packaging material, the unit comprising:a frame;at least one electron beam emitter fitted to the frame, along a path of material for processing, the at least one electron beam emitter having a flange for connection to the frame; anda locking device fitted to the frame to lock the emitter with respect to the frame in a work position, the locking device comprising a thrust system configured to exert a lock force on said flange in a first direction perpendicular to a second direction along which the flange is inserted into the frame, and an actuation system configured to activate the thrust system, the actuation system comprising a rotatable toggle actuating system rotating at least a portion of the thrust system forward with respect to the frame to lock the flange of the emitter to the frame. 2. The unit as claimed in claim 1, wherein the frame comprisesat least one fixed guide extending in the second direction perpendicular to said first direction, anda channel along which the material for processing travels, and which communicates with the outside through at least one opening bounded outwards by a flat rim crosswise to said first direction,wherein the flange comprises a connecting system configured to engage said guide in sliding manner, and configured to allow the emitter to translate in the second direction to and from an idle position, in which the flange is positioned facing said opening and at a given distance from said rim. 3. The unit as claimed in claim 2, wherein the flange comprises a center portion and two end portions, said connecting system being configured so that, when the emitter is in the idle and work positions, the flange rests on the guide solely by said end portions. 4. The unit as claimed in claim 2, wherein, when the emitter is in the idle position, the connecting system engages the guide in a transversely sliding manner, to allow the flange to translate, parallel to itself, in the first direction, and to move the emitter from the idle position to the work position, in which the flange is sealed to said rim. 5. The unit as claimed in claim 1, wherein the thrust system comprises a plurality of pressure members, andthe toggle actuating system comprises a plurality of toggle mechanisms, each of the toggle mechanisms being associated with a respective pressure member and movable between a rest position, in which the pressure member does not engage the flange, and a work position, in which the pressure member exerts a force in the first direction on the flange. 6. The unit as claimed in claim 5, wherein the toggle mechanisms divided into two groups located on opposite sides of the flange to cooperate, in use, with respective peripheral portions of the flange, the actuating system comprising, for each group of toggle mechanisms, a control member configured to activate the respective toggle mechanism. 7. The unit as claimed in claim 6, wherein each toggle mechanism comprisesa crank that rotates about a fixed first axis crosswise to the first direction, anda rocker arm interposed between the crank and the frame, the rocker arm comprising a first arm and a second arm arranged in a V-shape, and being hinged about a second axis, parallel to the first axis, to oscillate in a plane parallel to the first direction, the first arm being connected by a hinge pin to a free end of the crank to define a toggle with the crank, and to oscillate about a third axis parallel to the first axis, the second arm having a free end portion, which extends towards the frame and defines said pressure member for the respective toggle mechanism. 8. The unit as claimed in claim 7, wherein each control member is defined by a respective shaft coaxial with the second axis, the rocker arm comprising a center hub connected angularly to said shaft with an amount of rotational slack. 9. The unit as claimed in claim 7, wherein the rest position and work position of the respective toggle mechanism are located on either side of a dead center position, in which said toggle is extended and the pressure member exerts maximum thrust. 10. The unit as claimed in claim 7, wherein the pressure member and the first axis are located on opposite sides of the second axis, the crank being hinged on a pin rotatable about the first axis and comprising at least one lever, which has a first end portion engaging in an axially sliding manner a radial hole through said pin, and a second end portion connected to the first arm by said hinge pin,wherein an elastic system is interposed between said first end portion and the second end portion to exert on said hinge pin a preselected amount of thrust directed perpendicularly to the third axis. 11. An electron beam sterilization unit for processing food packaging material, the unit comprising:a frame;at least one electron beam emitter fitted to the frame along a path of the food packaging material, the at least one electron beam emitter comprising:a casing housing a gun that accelerates electrons;a flange connectable to the frame; anda foil extending across a window in the flange; anda locking device fitted to the frame to lock the emitter relative to the frame in a work position, the locking device comprising an arm mounted on a rotatable shaft to rotate together with the shaft, the arm possessing an end adjacent the flange, the arm including a pressure finger at the end of the arm adjacent the flange to contact the flange as the shaft and flange are rotated and to urge the flange of the emitter into sealing contact with the frame. 12. The unit as claimed in claim 11, wherein the locking device comprises a plurality of arms mounted on the shaft to rotate together with the shaft, each arm possessing an end adjacent the flange, each arm including a pressure finger at the end of the arm adjacent the flange to contact the flange and urge the flange of the emitter into sealing contact with the frame. 13. The unit as claimed in claim 11, wherein the flange includes two sides and comprises a pair of runners, each runner being positioned along one of the sides of the flange, each flange being fitted in and movable along a respective guide on the frame. 14. The unit as claimed in claim 11, wherein the locking device includes a crank mounted to oscillate about an axis, the arm being a first arm of a rocker arm that also includes a second arm, the crank including an end portion that directly contacts the second arm. 15. The unit as claimed in claim 14, wherein the locking device comprises a plurality of arms mounted on the shaft to rotate together with the shaft, the plurality of arms constituting a first group of arms located along one side of the flange, the locking device further comprising a second group of arms located on an opposite side of the flange and each including a pressure finger to contact the flange and urge the flange of the emitter into sealing contact with the frame. 16. The unit as claimed in claim 11, wherein the locking device includesa rod mounted to oscillate about an axis and a head at one end of the rod, the rod being slidingly fitted in a pin so that the rod is slidable relative to the pin, anda spring surrounding the rod and positioned between the head and the pin,wherein the arm is a first arm of a rocker arm that also includes a second arm, the head directly contacting the second arm. 17. The unit as claimed in claim 11, wherein the arm rotates about an axis of the rotatable shaft to rotate together with the shaft. 18. An electron beam sterilization unit for processing food packaging material, the unit comprising:a frame;at least one electron beam emitter fitted to the frame, along a path of material for processing, the at least one electron beam emitter having a flange for connection to the frame; anda locking device fitted to the frame to lock the emitter with respect to the frame in a given work position, the locking device comprising a thrust system configured to exert a lock force on said flange in a first direction, and an actuation system configured to activate the thrust system, the actuation system comprising a toggle actuating system including at least one toggle mechanism comprisinga crank that rotates about a fixed first axis crosswise to the first direction, anda rocker arm interposed between the crank and the frame, the rocker arm comprising a first arm and a second arm arranged in a V-shape and being hinged about a second axis, parallel to the first axis, to oscillate in a plane parallel to the first direction, the first arm being connected by a hinge pin to a free end of the crank to define a toggle with the crank, and to oscillate about a third axis parallel to the first axis, the second arm having a free end portion, which extends towards the frame and locks the flange to the frame.