Futaba Denshi Kogyo Kabushiki Kaisha

Futaba Corporation

Yasuo Ishiwata

Hiroaki Kawasaki

Chisato Akinari

Yutaka Hiroshima

Sho Sekiguchi

A sensor installed into a mold including a cable insertion member having a fixing portion with a fitting recess is provided. The sensor includes an optical fiber a part of which is bendable, and a fiber holder having a fiber insertion portion through which the optical fiber is inserted and a to-be-fixed portion extending from the fiber insertion portion. Further, the to-be-fixed portion is fixed to the fixing portion while being fitted to the fitting recess.

Sensor

An abnormal mold detector is provided that can previously detect the breakage of a mold tool with an ejector plate. A pressure sensor is attached to the ejector pin of a mold to detect the mold internal pressure. The operation status of the mold is detected by the sensor attached to the mold piece of the mold. An abnormality detector, formed of a CPU, processes the detected pressure signal and the mold working state indicating signal. The abnormality detector sets a reference value D exceeding a normal sticking resistance of the ejector pin. As a material is injected, the mold internal pressure increases during one cycle (A and B) in the molding step. After the molding process, the ejection process is carried out by the ejector pin during the value C. When a sticking resistance exceeding the value D is confirmed during the monitoring operation (FF), the abnormality detector decides that there may be the possibility that an abnormal state occurs in the mold tool. Thus the abnormality detector issues an alarm signal to the operator to halt the operation of the molding machine.

Abnormal mold detector

An ejector pin with a pressure sensor is provided, of which the sensor output can be utilized without any correction even in different diameter thereof, so that no design changes are required according to loads to the ejector pin. The ejector pin has a bar portion for extruding a molded component and a sleeve portion slidably housing the bar portion. The end of the bar portion faces the cavity from the opening at the end of the guide portion. A housing room is defined by the step portion at the lower end of the sleeve portion. A strain producing portion with an U-shaped cross section fixed on the base end of the bar portion is disposed inside the housing room. A strain sensor is attached on the lower surface of the beam of the strain producing portion. Only the area of the end of the bar portion is related to the pressure detection. When the pressure of a resin is applied on the end of the bar portion, the downward load on the bar portion bends the beam down. The strain sensor outputs a signal corresponding to the load and the pressure is worked out. By separately preparing plural kinds of sleeve portions with different outer diameters, the thickness of an ejector pin can be arbitrarily set according to conditions.

Growing community of inventors

Mobara, Japan

Yasuo Ishiwata