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:
Jul. 21, 1998
Filed:
Jun. 07, 1996
Norihiro Iwamoto, Sagamihara, JP;
Shinobu Kodama, Zama, JP;
Toshiba Kikai Kabushiki Kaisha, Tokyo-To, JP;
Abstract
A method of controlling vacuum in vacuum die-casting and a vacuum control system for performing the same adjusts the time to open a vacuum valve to start degassing in connection with the position of an injection plunger to control vacuum in a cavity so that gases may not be involved in a molten metal injected into the cavity. The method comprises opening the vacuum valve to start degassing the cavity upon the advancement of the injection plunger to a first position. The vacuum in a vacuum system is measured upon the arrival of the injection plunger at a second position immediately before a final position where the injection plunger completes the injection of the molten metal. A measured vacuum is compared with a predetermined reference vacuum. The first position is shifted by a predetermined distance toward the die when the measured vacuum is higher than the reference vacuum or by a predetermined distance away from the die when the measured vacuum is lower than the reference vacuum to set a corrected first position. The vacuum valve is opened when the injection plunger arrives at the corrected first position in the next injection cycle.