Magnetic coupling assembly for conveyor rollers

A magnetic coupling assembly to selectively couple a drive element of a longitudinal conveyor to at least one conveyor roller;

• said coupling assembly comprising:
• a driving portion configured and sized to be mounted to the conveyor;
• said driving portion being so configured as to be rotatably driven about a rotation axis by the drive element of the conveyor;
• a driven portion so linked to said driving portion as to rotate about said rotation axis;
• said driven portion including an external surface configured and sized to be brought in contact with at least one conveyor roller;
• an axially movable element mounted to one of said driving and driven portions;
• said axially movable element being provided with a first friction surface;
• the other of said driving and driven portions including a second friction surface facing said first friction surface;
• wherein one of said axially movable element and the other of said driving and driven portions is provided with a magnetic field generating element;
• the other of said axially movable element and the other of said driving and driven portions being provided with an element made of magnetic material;
• and
• wherein said first and second friction surfaces are brought into constant contact by a an adjustable magnetic force present between said magnetic field generating element and said element made of magnetic material, and wherein an increase or decrease in said magnetic force is translated into a corresponding increase or decrease in a frictional force between said first and second friction surfaces.