Grid element and an apparatus incorporating the grid element for assisting in the stacking and destacking of products from a surface

An apparatus for lifting one or more objects by means of suction, which apparatus comprises a vacuum chamber, a grid element forming the floor of the vacuum chamber, and means for creating a vacuum in the vacuum chamber, the grid element comprising a two-dimensional array of cells each of which opens directly onto each opposite major surface of the grid element, each cell having at least one valve member for closing and opening of the cell, the valve member(s) normally assuming a first position wherein the cell is open to provide direct communication through the cell between the opposite major surfaces of the grid element but being movable by a sufficient flow of air through the cell into a second position wherein the cell is substantially closed against such communication, wherein each valve member comprises a flap valve pivoted for rotation between the first position and the second position, and means for supporting the grid element within the vacuum chamber,

• wherein each flap valve is biased into the first position solely by its weight.

An apparatus for lifting one or more objects by means of suction, which apparatus comprises a vacuum chamber, a grid element forming the floor of the vacuum chamber, and means for creating a vacuum in the vacuum chamber, the grid element comprising a two-dimensional array of cells each of which opens directly onto each opposite major surface of the grid element, each cell having at least one valve member for closing and opening of the cell, the valve member(s) normally assuming a first position wherein the cell is open to provide direct communication through the cell between the opposite major surfaces of the grid element but being movable by a sufficient flow of air through the cell into a second position wherein the cell is substantially closed against such communication, wherein each valve member comprises a flap valve pivoted for rotation between the first position and the second position, and means for supporting the grid element within the vacuum chamber,

• wherein each cell has a pair of flap valves so that, in use, both flap valves may be simultaneously in the first position or simultaneously in the second position or one of the valves may be in the first position while the other one may be in the second position.