A pneumatic device for continuously varying the pressure of compressed air for feeding pneumatic actuators, comprising a pressure regulation device, which is adapted to receive in input an unregulated pressure line and to provide in output a regulated pressure; an error amplifier, which is adapted to drive an actuation device, which in turn is adapted to actuate the pressure regulation device; and a pressure transducer, which is adapted to detect a pressure value downstream of the pressure regulation device and to feed it back to the error amplifier, for closed-loop control of the pressure regulation device.

The machine for machining edges, particularly of glass plates, includes, on a supporting structure, mutually opposite conveyors which extend continuously and are suitable for moving the plates to be machined at machining heads. At least one of the conveyors has a plurality of adjacent sliding blocks each of which includes an elongated supporting body on which a covering is provided which has blocks for gripping the plates being machined. The elongated supporting body has, inside it, a T-shaped seat for slidingly retaining and guiding a rod-like element to which a pad is connected; the pad can be arranged at a presettable distance from the blocks, which have a fixed vertical placement with respect to the machining surface.