A pressure generating device having a piston and cylinder unit including a piston acting on both sides, which separates two working spaces (3a, 3b) within the cylinder from one another in a sealing manner, wherein the piston has two, in particular differently dimensioned effective areas (A1, A2), and each effective area (A1, A2) of the piston respectively delimits one working space (3a, 3b), wherein each working space (3a, 3b) is in communication with a hydraulic circuit (K1, K2) via a hydraulic line (H3, H4), wherein at least one hydraulic chamber of a load (V1, V1K1, V1K2, V2K, V3K, V4K) is connected to each hydraulic circuit (K1, K2), wherein a drive drives the piston of the piston and cylinder unit, characterized in that either - each working space (3a, 3b) is in communication with a reservoir for a hydraulic medium by means of a hydraulic line (H1, H2), wherein at least one switching valve (PD1, PD2) is arranged in each hydraulic line (H1, H2) for optionally blocking or opening the hydraulic line (H1, H2), wherein the pressure from a hydraulic circuit (K1, K2) is released into the reservoir via the respective working space (3a, 3b) and the respective hydraulic line (H3, H4), when the switching valve (PD1, PD2) is open; or - one or both working space/s (3a, 3b) is or are in communication with a reservoir for a hydraulic medium by means of a hydraulic line (H1, H2), wherein in one or in both hydraulic line(s) (H1, H2), a switching valve (PD1, PD2) is arranged for optionally blocking or opening the hydraulic line (H1, H2), and wherein the pressure from a hydraulic circuit (K1, K2) is released into the reservoir via the respective working space (3a, 3b) and the respective hydraulic line (H3, H4), when the switching valve (PD1, PD2) is open; and/or one or more hydraulic chamber(s) of the loads each has or have an outlet valve (AVi) assigned for directly releasing pressure from the respective chamber into the reservoir, and that the pressure spaces (3a, 3b) and/or the hydraulic lines (H3, H4) are in communication with one another via a connecting line, wherein a switching valve (ShV) for optionally opening or blocking the connecting line is arranged within the connecting line. - each working space (3a, 3b) is in communication with a reservoir for a hydraulic medium by means of a hydraulic line (H1, H2), wherein at least one switching valve (PD1, PD2) is arranged in each hydraulic line (H1, H2) for optionally blocking or opening the hydraulic line (H1, H2), wherein the pressure from a hydraulic circuit (K1, K2) is released into the reservoir via the respective working space (3a, 3b) and the respective hydraulic line (H3, H4), when the switching valve (PD1, PD2) is open; or - one or both working space/s (3a, 3b) is or are in communication with a reservoir for a hydraulic medium by means of a hydraulic line (H1, H2), wherein in one or in both hydraulic line(s) (H1, H2), a switching valve (PD1, PD2) is arranged for optionally blocking or opening the hydraulic line (H1, H2), and wherein the pressure from a hydraulic circuit (K1, K2) is released into the reservoir via the respective working space (3a, 3b) and the respective hydraulic line (H3, H4), when the switching valve (PD1, PD2) is open;