PRESS FOR MOLDING PIPES OF A LARGE DIAMETER SUBSTANCES Russian patent published in 2004 - IPC

FIELD: presses for molding pipes of a large diameter.

SUBSTANCE: the invention is dealt with the press for forming pipes of a large diameter from U-shaped molded sheets in a cylindrical preform with a spline. The press contains some presses, located in a row in one unit corresponding to the length of the molded pipes of a large diameter. Each press of the indicated row contains the lower instrument and the upper instrument mounted with a capability of a vertical reciprocating motion by means of a hydraulic cylinder. Each press of the row is made as a single-rack-mount. The hydraulic cylinder is made as a cylinder of a speeded up run and has a body, a main piston and a guided elongated auxiliary piston directed a body positioned in the center or in the main piston. The main piston has a diameter exceeding the diameter of the auxiliary piston and has a blind hole. The mentioned auxiliary piston and the main piston are made with the channels for feeding of a pressure-flow. The channels are located correspondingly on the piston surface of the auxiliary piston and on the ring surface of the basic piston free from the auxiliary piston. The auxiliary piston is installed with one its setting end placed in the mentioned blind hole of the basic piston and linked with the latter by a brace rod. The press is supplied with an additional container, which is linked with the channels of the main piston used for feeding of a pressure flow. In result it allows to reduce dimensions of the press and the oil consumption.

EFFECT: the invention ensures a reduction of dimensions of the press and decrease of the oil consumption.

3 cl, 1 dwg