Hydrolux S.a.r.l.

Husky Injection Molding Systems Limited

Bernd Lanfermann

Arsene Bourkel

Karl Tratberger

Karl-Heinz Post

Pierre Mailliet

Karl H Post

A closing unit for an injection moulding machine has a movable closing die and a fixed matching die, as well as several hydraulic cylinders mounted on the fixed matching die to generate the closing force. The closing die has a drawbar for each hydraulic cylinder. The piston of each hydraulic cylinder is mechanically linked to a rotary locking bushing. The drawbars extend through hydraulic cylinders and locking bushings. A servo-drive allows the locking bushings to swivel up to a first and second angular position. First locking elements located along a section of the drawbars cooperate with second locking elements in the locking bushings so that in the first angular position the drawbars may be axially pushed through the hydraulic cylinders and the locking bushings, and in the second angular position the closing force may be transmitted from the hydraulic cylinders to the closing die.

Closing unit for injection moulding machine

Pilot-operated servo-valve

A two-port cartridge type seat valve has a valve sleeve with a stepped guide bore for a poppet. The poppet includes a piston flange that divides the second step of the guide bore axially into an end-face first pilot chamber and an annular second pilot chamber. A first connection channel through the valve sleeve connects the annular second pilot chamber with an annular chamber into which a lateral main flow port opens. The free cross-section of a valve seat and of an axial main flow bore correspond approximately to the cross-section of the first step of the guide bore.

Two-port cartridge seat valve

A pilot stage for pressure control valves includes an axially displaceable valve piston which bounds a valve chamber axially on one side and includes a valve seat for a closure cone therein. Valve piston has an actuating surface in a pressure chamber that is substantially larger than the free cross section of the valve seat. By pressurization of this pressure chamber, a large hydrostatic force is exerted on the valve piston which opposes the closing force of the pressure-setting spring. A housing stop fixes a first axial end position of the valve piston in the direction of this hydrostatic force. The pilot control stage has improved properties for both manually adjustable pressure control valves and proportional pressure control valves.

Pilot stage for pressure control valves

A pilot-operated servo valve design for efficient mounting in a control block has at least three main-stream ports. An opening into a control sleeve for a first main-stream port is disposed opposite an end surface of a main control piston. The main control piston has a pressure-equalizing surface disposed in a pressure-equalizing chamber, which is fluidically coupled by a pressure-equalizing duct in the main control piston to the first main-stream port. A return spring urges the main control piston toward a first axial end stop to clearly define a safety position. The valve exhibits good dynamic properties.

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Rees, Germany

Bernd Lanfermann