Suction pads

Claim 2

A flat suction pad of substantial dimension for lifting large flat articles, said pad comprising: A flexible elastomer holding surface for engagement with an upper surface of said article, a flat backup member disposed behind said holding surface opposite said article to prevent substantial concave deformation of said surface away from said article, an evacuatable chamber in communication with said surface, inlet means for connection with a vacuum source, partition means dividing said chamber into a plurality of subchambers each associated with a particuLar region of said surface, and valve control means in the backup member for effectively connecting different ones of said subchambers of the pad with said inlet means thereby changing the part of said surface which is effective at any instant for the application of a lifting force on said article by applying said lifting force to the said particular region of said surface associated with said different ones of said subchambers.

Claim 3

A suction pad for lifting an article, said pad comprising: a flexible holding surface comprising an apertured membrane for engagement with said article, an evacuatable chamber in communication with said surface, inlet means for connection with a vacuum source, partition means dividing said chamber into a plurality of subchambers each associated with a particular region of said surface, and control means comprising a plurality of vertically displaceable members, each of which in its lowest position depresses said membrane to define a respective downwards projection in the lifting surface of the associated region of the pad and wherein said control means is adapted to connect different subchambers of the pad with said inlet means thereby to determine which part of said surface is effective at any instant for the application of a lifting force on said article.

Claim 4

A suction pad for lifting an article, said pad comprising: a flexible holding surface comprising an apertured membrane for engagement with said article, an evacuatable chamber in communication with said surface, inlet means for connection with a vacuum source, partition means dividing said chamber into a plurality of subchambers each associated with a particular region of said surface, and control means comprising a plurality of vertically displaceable members, each of which in its lowest position depresses said membrane to define a respective downwards projection in the lifting surface of the associated region of the pad and wherein said control means is adapted to connect different subchambers of the pad with said inlet means thereby to determine which part of said surface is effective at any instant for the application of a lifting force on said article.

Claim 5

A suction pad as claimed in claim 2, comprising a first chamber adapted for connection to a vacuum source, an apertured membrane adapted to provide said holding surface, a second chamber in communication with the upper surface of said membrane, an apertured partition means separating said first chamber from said second chamber, a plurality of imperforate members located between said partition means and said membrane, said partition members being arranged to divide said second chamber into two or more subchambers such that each subchamber is associated with one or more apertures of said partition means and with a particular region of the holding surface, each of said vertically displaceable valve members being arranged in its lowest position to close a respective one of the said apertures thereby to isolate the associated subchamber from said first chamber, whereas when that portion of the membrane which is associated with the particular subchamber concerned is brought into contact or partially into contact with the surface of an article to be lifted, the valve member associated with the subchamber is moved upwards from its lowest position so as not to prevent the membrane from assuming the same contours as those of the surface of the article to be lifted, this movement of the valve member being effective to unseat the valve member from its associated aperture and to provide a connection between the associated region of the holding surface and said first chamber.