| 摘要 |
The invention relates to a device (10) for producing and/or processing plastic material mixtures comprising a mixing head (11) which has one or several inlets (15) for the mixture constituents and in which a mixer (17) provided for mixing the constituents is rotationally driven. An outlet (22) is provided in the mixing head for ejecting the finished mixture. Said outlet can be closed or opened by the head of the mixer in the manner of a nozzle needle. To this end, the mixer is arranged in the housing (12) of the device such that it can be axially displaced. In order to prevent an abrupt opening or closing of the outlet, which can thus lead to losses in quality when using sensitive plastic materials, the invention provides that the raising and lowering of the mixer in the mixing head is effected via a mechanical cam drive (40) comprising at least one actuating cam (42) which interacts with a lifting element (60) that acts upon the mixer (17) or the shaft thereof (24). Since the actuating cams can be fabricated and used in any desired contour, the invention makes it possible, when opening the outlet (22), to firstly lift the mixer slowly from the opening and then to continuously increase the opening speed, whereby the plastic material mixture in the mixing chamber can immediately fill,the mixing chamber volume which increases during opening. In addition, reductions in pressure are prevented thus avoiding consequential losses in the quality of the mixture. |
