IT1289394B1 - Hydraulic press for forming sheet metal plates or blanks by deep-drawing and bending - has arrangement which compensates the oil level by ensuring the constancy of the volume of the oil container by expelling or feeding fluid out of or into the container - Google Patents

Abstract

The hydraulic apparatus consists of a first chamber 2/10 for the compression of the hydraulic fluid, a second chamber for the expansion of the same hydraulic fluid, and a sealed conduit 2/4 connecting the inner volumes of the two chambers with each other. There is a piston 2/11 slidably arranged within the first chamber, adapted to slide hermetically relative to the inner walls of it and tightly compress the hydraulic fluid contained in it. There is a thrust element (2/12) adapted to press upon the outer perimeter of the piston, and a container adapted to delimit the surfaces containing the hydraulic fluid that is put under pressure. The container has an aperture (2/16) that enables the inner volume of it to communicate with the outside ambient, or with a tightly sealed expansion chamber (2/200). Shutting device (2/28) are provided that are capable of shutting the aperture. The shutting device are linked with motion transmission device (1/13) comprising move-away device (2/26) adapted to automatically keep the shutting device open when the device are disengaged from the thrust element, the motion transmission device being adapted to transfer the positions that can be taken by the piston to the shutting device until the latter eventually tightly shut the aperture.