| 摘要 |
The invention relates to an injection mould designed to shape thin-walled plastic pieces with an elongated opening, e.g. pieces in the form of a sleeve with a through opening or an opening plugged at one end.The study called "Construction of Injection Moulds for Thermoplastic Materials" by H. Zawistowski and D. Frenkler (Wyd. Naukowo-Techn., Warsaw, 1984) at page 298 and further presents a variety of construction solutions for moulds equipped with devices to flip off moulded pieces from a punch. Chapter 10.2.5 of that study discusses sleeve strippers designed to remove thin-walled pieces from a mould. A stripper of that kind is shaped as a sleeve built on a knock-out plate, its inner surface corresponding to the shape of a punch. After opening a mould a power transmission system causes a stripper to move along a punch and slip pieces off the mould.If oblique pins are used for power transmission, their length is limited by the height of a mould, which means that they cannot be used for removing pieces from long punches. On the other hand, application of hydraulic or pneumatic power transmission systems makes construction of a mould much more complicated and costly.The aim of this invention is to remove the above-mentioned disadvantages of known injection moulds by developing a new mechanically powered device for stripping moulded pieces from punches designed particularly to enable production of relatively long thin-walled pieces.According to the invention, a mould is equipped with a slidably mounted stripper placed on a punch. The stripper is connected through a reversible tension member with a rotary lever set on a bearing. The lever has an opening shaped as an obtuse angle, with one of its arms parallel to the axis of a closed mould. A pin, whose one end is slidably mounted on a knock-out plate, is placed in the opening. The knock-out plate is equipped with...
|
