The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 26, 1977
Filed:
Apr. 21, 1976
Klockner-Werke AG, Duisburg, DT;
Abstract
An injection-molding machine has a drive ram with a pressurizable chamber that can be connected either to the high-pressure side or the low-pressure side of a source of fluid under pressure. A control system operating this machine has a pressure-reducing valve with an inlet port connected to the high-pressure side of the source, an outlet port connected through a cut-off valve and a throttle to the chamber of the ram, and a pilot port pressurizable to control the pressure at this outlet port. A pressure-relief valve has an inlet port connected to the pressurizable ram chamber, an outlet port connected to the low-pressure side of the pressure source, and a pilot port pressurizable to control the pressure differential across this pressure-relief valve. A pressure-control valve has an outlet side connected to the low-pressure side of the source and an inlet side and is operable to maintain a first predetermined pressure differential between its inlet and outlet sides in an injection mode and to maintain a certain predetermined pressure differential between its inlet and outlet sides in a clamping mode. A check valve has one side connected to the pilot port of the pressure-reducing valve and another side connected to the pilot port of the pressure-relief valve for fluid flow only from the former to the latter. A function-control valve has a first connection coupled to the inlet side of the pressure-control valve and a second and third connection each coupled to a respective one of the pilot ports. This function-control valve is operable between a filling position connecting the pilot port of the pressure-relief valve to the pressure-control valve and an injecting/holding position connecting the pilot port of the pressure-reducing valve to the pressure-control valve.