Apparatus and method for capping containers

A capping apparatus adapted to apply caps provided with a thread to the neck of containers, the capping apparatus comprising:

• a first rotatable carousel having circumferentially a first plurality of seats where the containers can be housed with random orientation of their thread, a second rotatable carousel having circumferentially a second plurality of seats where the caps can be housed with random angular orientation of their thread,
• an optical reconstruction station having:
• a first filming means for filming images having a first framing field oriented on the thread of the containers in sequential transit through said first framing field,
• a second filming means for filming images having a second framing field oriented on the thread of the caps in sequential transit through said second framing field,
• a processing and control means adapted to:
• acquire from said first and second filming means at least one current image of the thread of the container in transit through said first filming field and at least one current image of the thread of the cap in transit through said second framing field,
• calculating a current value of an angular position of the thread of said cap in transit through said second framing field and a current value of an angular position of the thread of said container in transit through said first framing field,
• comparing said at least one current image with an optical reconstruction thereof preliminarily learned, and
• programming the operation of the screwing means with the calculated value of the current angular position of the thread of the cap in transit through said second framing field and the calculated value of the current angular position of the thread of the container in transit through said first framing field,
• where the preliminary optical reconstruction of the thread of the cap is learned by said processing and control means by acquiring through said second filming means a number of multiple sequential images of the thread of the cap in 360° rotation on the axis of the cap and in the seat of the cap of the second carousel starting from a random angular orientation, for a number of positions of the cap inside the second framing field while the second carousel is stationary, and
• where for learning the preliminary optical reconstruction of the thread of the container, said processing and control means acquire through said first filming means a number of multiple sequential images of the thread of the container in 360 rotation on the axis of the cap and in the seat the cap of the first carousel starting from a random angular orientation, for a number of positions in which the container s inside the first framing field while the first carousel is stationary, and
• wherein in order to calculate said current value of the angular position of the thread of the container
• in transit, said processing and control means acquire from said first filming means a single current image of the thread of the container in transit while said first carousel rotates, and processes a similarity function between said current image and the preliminary optical reconstruction of the thread of the container.