Machine press

摘要

In a machine press having a lower and an upper tool carrier, a hydraulic drive acting on the upper tool carrier comprises at least one closed hydraulic drive system that can be switched between rapid motion and press motion, the drive system having at least one hydraulic cylinder piston unit. The hydraulic liquid of the at least one hydraulic drive system is stored in a pressure accumulator fanning the storage container, supplying the entire associated hydraulic drive system. permanently with at least a base pressure above the ambient pressure. There is no hydraulic connection whatsoever between the working chamber on the piston rod side and the working chamber on the piston side of at least one hydraulic cylinder piston unit. The upper tool carrier is pre-stressed into its upper position by a spring unit.

主权项

1. A machine press (1), especially a folding press, comprising:
a machine structure (3), a lower tool carrier (4) disposed in fixed spatial relationship to the machine structure and an upper tool carrier (7), which can be moved linearly up and down (A) by an operating stroke (H) relative to the lower tool carrier, and with a hydraulic drive (10), which acts on the upper tool carrier and causes the downwardly directed movement of the upper tool carrier, and which is provided with at least one closed, independent hydraulic drive system (8; 9), which in turn comprises at least one hydraulic cylinder-piston unit (12; 12′A, 12′B) and at least one hydraulic assembly (15, 15′, 15″) pressurizing it and supplied from a storage container; wherein the at least one hydraulic drive system (8; 9) can be changed over between rapid motion, in which a first effective piston area (27; 45) is pressurized by the at least one hydraulic drive system, and press motion, in which the at least one hydraulic drive system pressurizes a second effective piston area (48; 47) that is substantially larger than the first effective piston area; wherein the hydraulic fluid of the at least one hydraulic drive system of the hydraulic drive which applies force to cause the downwardly directed movement of the upper tool carrier is stored in a pressure accumulator (19), which constitutes the storage container and constantly imposes at least a base pressure higher than the ambient pressure on the entire hydraulic drive system in question; wherein no hydraulic communication of any kind exists between a working chamber (22; 22′B) on a piston-rod side and a working chamber (24; 24′B) on a piston side of at least one hydraulic cylinder-piston unit (12; 12′B) of the at least one hydraulic drive system; and wherein the upper tool carrier (7) is forced into its upper end position by means of a spring device (21), which overcompensates the weight of the upper tool carrier, of the tool mounted thereon and of the components of the hydraulic drive associated with the upper tool carrier as well as the closing force implied by the base pressure prevailing in the at least one hydraulic drive system.