Hydraulic stretching
AssigneeKrones AG
InventorUlrich Lappe
Life of this patent
Estimating the term…
Abstract
A stretching system for stretch-blow molding machines for stretch blow molding containers from preforms, having at least one stretching unit which is hydraulically actuated for stretching a preform, with a hydraulic pressure tank which is at least partially filled with a hydraulic medium, for example water, and which is at least partially filled with a gaseous medium, for example compressed air; and wherein the stretching unit includes a stretching cylinder and a stretching piston, the stretching system being designed to conduct the hydraulic medium out of the hydraulic pressure tank to the stretching cylinder of the stretching unit, whereby the stretching piston in the stretching cylinder can be moved hydraulically.
Claims23
A stretching system for stretch-blow molding machines for stretch-blow molding containers from preforms, comprising at least one stretching unit which is hydraulically actuated for stretching a preform, with a hydraulic pressure tank which is at least partially filled with a hydraulic medium, and which is at least partially filled with a gaseous medium, the stretching unit comprising a stretching cylinder and a stretching piston, the stretching system designed to conduct the hydraulic medium out of the hydraulic pressure tank to the stretching cylinder of the stretching unit, whereby the stretching piston can be hydraulically moved in the stretching cylinder;
- further comprising a second tank for accommodating the hydraulic medium which is conducted out of the stretching cylinder when the stretching piston is moved in the stretching cylinder, wherein the second tank is provided in at least one line for returning the hydraulic medium and further comprising a pump, the pump being provided between the second tank and the hydraulic pressure tank.
A method of stretching preforms by a stretching system having at least one stretching unit, wherein the stretching unit comprises a stretching cylinder and a stretching piston, and with a hydraulic pressure tank which is at least partially filled with a hydraulic medium, and at least partially filled with a gaseous medium, the stretching comprising at least one supply line, and at least one line for returning the hydraulic medium to the hydraulic pressure tank, the method comprising:
- stretching a preform by hydraulic actuation of the stretching unit;
- supplying the hydraulic medium to the stretching cylinder of the stretching unit through the at least one supply line;
- and
- moving the stretching piston in the stretching cylinder via the supplied hydraulic medium;
- wherein the stretching system furthermore comprises a pump, the pump being provided in the at least one line for returning the hydraulic medium, wherein the stretching system further comprises a second tank for accommodating the hydraulic medium which is conducted out of the stretching cylinder when the stretching piston is moved in the stretching cylinder, wherein the second tank is provided in the at least one line for returning the hydraulic medium, and wherein the pump is provided between the second tank and the hydraulic pressure tank.
A method of retrofitting blow molding stations of stretch-blow molding machines, comprising:
- replacing at least one pneumatic stretching system with a pneumatic stretching unit by a stretching system for stretch-blow molding machines for stretch-blow molding containers from preforms, comprising at least one stretching unit which is hydraulically actuated for stretching a preform, with a hydraulic pressure tank which is at least partially filled with a hydraulic medium and which is at least partially filled with a gaseous medium wherein, the stretching unit comprising a stretching cylinder and a stretching piston, the stretching system designed to conduct the hydraulic medium out of the hydraulic pressure tank to the stretching cylinder of the stretching unit, whereby the stretching piston can be hydraulically moved in the stretching cylinder;
- furthermore comprising a second tank for accommodating the hydraulic medium which is conducted out of the stretching cylinder when the stretching piston is moved in the stretching cylinder, wherein the second tank is provided in the at least one line for returning the hydraulic medium, and further comprising a pump, the pump being provided between the second tank and the hydraulic pressure tank.
Dependencies are inferred from the claim text.